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Objective: To study the effect of a modified alar base cinch suture (ABCS) based on nasal musculature anatomy on the three-dimensional morphology of nasolabial region in patients after Le Fort Ⅰ osteotomy., Methods: In the study, 30 patients[11 males and 19 females, with an average age of (23.23±2.98) years]with skeletal Class Ⅲ malocclusion underwent orthognathic surgery between August, 2019 and January, 2020 to have the maxilla advanced no more than 4 mm in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology were involved and were divided into the test and control groups based on the random number table.In the test group, the nasal musculature was identified and labeled before dissection and the ABCS was according to the label, while in the control group, the nasal musculature was directly sutured and knotted in the midline of nose without prepend labeling.All the patients underwent three-dimensional facial photos preoperatively and 6 months postoperatively by using 3dMD face system.On the three dimensional image, soft tissue landmarks of nasolabial region was identified by the same examiner.Fourteen measurements including straight distance, curve distance, angle and ratio were measured.Statistical analysis was done by using SPSS 22.0., Results: There were significant differences between the two groups in cutaneous height of upper lip ( P =0.023) and in nasal tip protrusion-alar width ( P =0.012).The increase rate of cutaneous height of upper lip and the decrease rate of nasal tip protrusion-alar width in the control group were significantly higher than that in the test group.The alar width and alar base width of the both groups were significantly increased compared with the preoperative level ( P < 0.05).The nasolabial angle in the control group was significantly higher compared with the normal value, while there was no significant difference between the test group and the normal value., Conclusion: Compared with the conventional suture method, this modified alar base cinch suture is more favorable for the postoperative nasal coordination and nasolabial morphology in patients who need mild to moderate maxillary advancement, and it has certain advantages in operability and objective accuracy.So it could become a modified and accurate method of alar base cinch suture and be widely applied in clinical practice.

Objectives: Breast surgery requires a high aesthetic outcome and should be individualized according to anthropometric breast and body characteristics. This study aimed to measure the anthropometric parameters and volume of Vietnamese female breasts and their application in breast surgery., Subjects and Methods: A cross-sectional descriptive study enrolled 240 women treated at Vietnam National Cancer Hospital aged 18 to 78 years old. The measurements were obtained with the patient sitting upright in the anatomic position based on key landmarks and breast volume was also assessed. Differences in breast anthropometric measurements and breast volume were compared between groups of age, BMI, and the number of children. The correlation between breast volume calculated by anthropometric method and surgical specimen volume was evaluated to determine the accuracy of this method., Results: The mean values of the right and left breast volumes are less statistically different. Mean breast volume of the right breast and left breast were 396.1±182.3ml and 399.4±182.2ml, respectively. The proportion of breast ptosis increased with age (p=0.027), Body mass index (p<0.0001), and the number of children (p=0.004). The most important factor affecting the size and shape of the breast was body mass index (BMI). Mastectomy specimen volume and breast volume calculated by the anthropometric method are highly correlated with r=0.966., Conclusions: The results of this study should be applied in clinical practice in breast surgery for Vietnamese women., .

Background: Occipital artery (OA)-posterior inferior cerebellar artery (PICA) bypass is a challenging procedure and is not frequently performed owing to the difficulty of OA harvest. To facilitate harvest, the intersection between the sternocleidomastoid and splenius capitis (the OA triangle) is used as the anatomical landmark to identify the OA segment that carries the highest risk of damage. This clinical study aimed to demonstrate efficacy and safety of OA harvest using this landmark., Methods: The study included 18 patients who underwent OA harvest using the OA triangle as a landmark for treatment of vertebral artery and PICA aneurysms. Patients were retrospectively evaluated for safety and patency of OA after harvest and OA-PICA bypass., Results: Of 18 patients with ruptured and unruptured vertebral artery and PICA aneurysms, 13 (72.2%) underwent OA-PICA bypass and 5 (27.8%) did not undergo bypass. The OA was completely harvested without damage in all patients. After harvest, the OA was patent in 17 patients (94.4%) and was occluded in 1 patient owing to vasospasm; this patient then underwent recanalization resulting in good patency of the OA-PICA bypass. The patency rate of the OA-PICA bypass was 100%., Conclusions: The OA triangle, which is the anatomical landmark of the proximal end of the transitional segment of the OA, facilitated OA harvest using the distal-to-proximal harvest technique with safety and good patency. To the best of our knowledge, this is the first study of OA harvest in clinical cases., (Copyright © 2021 Elsevier Inc. All rights reserved.)

For proximal femoral nailing, choosing the proper entry point with the aid of C-arm imaging is crucial. Therefore, obtaining accurate radiological views that facilitate sound identification of the tip of the greater trochanter (GT) is of utmost importance. The aim of this study was to define a radiological view characterised by reproducible radiographic landmarks which will allow the reliable identification of the tip of the GT in the anteroposterior view. Anatomical and radiographic features of 16 cadaveric femurs were analysed. The cortical overlap view (COV), characterised by the radiological overlap of the density line of the piriform fossa and the intertrochanteric crest, was identified. It marks the rotation of the proximal femur at which the GT can be accurately identified and used to determine the desired entry point for a proximal femoral nail. Trainees and fully qualified orthopedic trauma surgeons were asked to identify the correct COV in radiological imaging series. Mean internal rotation of the femur to achieve a COV was 17.5° (range 12.8°-21.8°). In the COV the tip of the GT is the highest visible point and the mean distance from the cortical overlap line to the tip of the GT is 4.45 mm. Intra- and inter-rater reliability was high with ICC(2,k) = 0.932 and ICC(2,k) = 0.987 respectively. Trainees achieved higher rates of correct COV identification than specialists. There was no significant correlation between the internal rotation of the femur to achieve the COV and femoral antetorsion. In conclusion, the COV is a highly reproducible radiological view that is characterised by radiographic landmarks easy to recognise. It allows for accurate identification of the tip of the GT, which can be used by the surgeon as a reference to determine the desired entry point for an intramedullary nail., (© 2021. The Author(s).)

Background: Previous CT and cadaver studies have suggested that the external obturator footprint might be used as a landmark for stem depth in direct anterior THA. Instructions on where to template this structure with small variability in height have been developed but have not been tested in daily clinical practice., Questions/purposes: In this study we sought to investigate the (1) usability, (2) accuracy, and (3) reliability of the external obturator footprint as a landmark for stem depth in direct anterior THA., Methods: The distance between the superior border of the external obturator tendon and the shoulder of the stem was measured intraoperatively in all patients (n = 135) who underwent primary THA via a direct anterior approach performed by the senior author between November 2019 and October 2020. The landmark was considered useful when two of thre`e evaluators agreed that the intersection of the vertical line comprised of the lateral wall of the trochanteric fossa and the oblique line formed by the intertrochanteric crest was clearly visible on the preoperative planning radiograph, and when the landmark was furthermore identified with certainty during surgery. Accuracy was defined as the degree of agreement (categorical for thresholds of 2 and 5 mm, the latter representing the threshold for developing unphysiological gait parameters) between the intraoperative distance and radiographic distance as measured on intraoperative fluoroscopy images or postoperative radiographs, which were calibrated based on femoral head sizes in a software program commonly used for templating. Intrarater reliability was defined as the degree of agreement (categorical for thresholds of 1 mm, which we considered an acceptable measurement error) between the ratings of one observer, who measured the radiographic distance on two different occasions separated by a washout period of at least 2 weeks. Interrater reliability was defined as the degree of agreement (categorical for thresholds of 1 mm, which we considered an acceptable measurement error) between the ratings of three observers with varying levels of experience (a fellowship-trained hip surgeon, a hip surgery fellow, and a medical student)., Results: The landmark was considered useful in 77% (104 of 135) of patients who underwent direct anterior THA based on the observations that the trochanteric fossa was clearly visible on the planning radiograph in 117 patients and that the tendon was identified with certainty during surgery in 118 patients. There was good-to-excellent accuracy (intraclass correlation coefficient 0.75-087), and intrarater reliability (ICC 0.99) and interrater reliability (ICC 0.99) were both excellent., Conclusion: This clinical study showed that the external obturator footprint is a useful, accurate, and reliable landmark for stem depth in direct anterior THA., Clinical Relevance: The external obturator landmark allows the surgeon to position the stem within a range of the templated depth that is beneath the threshold for the development of unphysiological gait parameters. Although strictly speaking it was found useful in 77% of patients in this study, we found that this percentage of usability can easily be improved to around 90% by providing the radiology lab technician with instructions to correct external rotation of the foot during the taking of the planning radiograph. Future studies could compare the established (in)equality in leg length in patients using the external obturator landmark with computer-assisted surgery., Competing Interests: Each author certifies that neither he or she, nor any member of his or her immediate family, has funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the Association of Bone and Joint Surgeons.)

Objectives: The aim of this study is to investigate the scutum-cochleariform process (CP) and scutum-promontorium distances according to the mastoid pneumatization condition., Methods: Two hundred temporal multidetector computed tomography scans (90 males and 110 females) were evaluated retrospectively. The scutum-CP and scutum-promontorium distances were measured. Facial canal dehiscence (FCD) in the tympanic segment and mastoid pneumatization were also evaluated., Results: The distances between scutum-CP and scutum-promontorium were not different between males and females and between right and left sides. Facial canal dehiscence in the tympanic segment was detected: 5.6% (right) and 7.8% (left) in males and 5.5% (right) and 10.0% (left) in females. Grade 4 (100%) pneumatization was detected mainly in 55.6% to 57.8% of the patients in both genders. Grade 0 (0%) pneumatization (sclerosis) was detected in 22.2% to 28.2% of both males and females. In more pneumatized mastoids, the scutum-CP and scutum-promontorium distances increased. In sclerotic mastoids, the scutum-CP and scutum-promontorium distances decreased. Facial canal dehiscence rates were not related to the mastoid pneumatization levels., Conclusion: Cochleariform process is an important landmark to localize the tympanic segment of the facial canal. In sclerosed mastoids, scutum-CP and scutum-promontorium distances decreased. There was no relationship between FCD rates and mastoid pneumatization levels. It may be due to the development of FCD that occurs during the intrauterine period. In endoscopic and classic ear surgeries, mastoid pneumatization must be evaluated preoperatively to avoid facial nerve injuries.

Objective: We aim to describe the parotid fascia as a landmark that can help identify the immediately underlying facial nerve trunk., Methods: Dissection of the parotid fascia and identification of the facial nerve trunk were carried out on 8 fresh cadaveric parotid glands. The attachments and arrangement of the parotid gland and its fascia were evaluated and histologically assessed, with special attention to the fascia overlying the facial nerve trunk., Results: The parotid fascia envelops the posterior aspect of the parotid gland in an open-book fashion. Posteriorly, it connects to the anterior and medial aspect of the mastoid tip. Posterosuperiorly, it attaches to the inferior aspect of the tragal pointer. Directly medial to the fascia lies the facial nerve trunk., Conclusion: The parotid fascia, particularly the parotid-mastoid segment overlying the facial nerve trunk, can be utilized as an additional landmark of depth to help identify the facial nerve trunk during a parotidectomy in conjunction with other commonly used standard anatomic landmarks. The parotid fascia sling spans from the mastoid and tragal pointer to the parotid gland and can be easily palpated intraoperatively. Once the fascia is removed, the facial nerve trunk is identified.

Objectives: Persistent or recurrent disease following excision of a thyroglossal duct cyst/sinus (TGDC) is often found in the suprahyoid region. Cadaver dissections were performed to identify and name important surgical landmarks in the suprahyoid area; a histopathologic analysis of surgical specimens was completed to determine the incidence and extent of microscopic disease; and clinical outcomes were compared to determine the efficacy of a specific anatomic dissection., Study Design: Retrospective case series., Methods: Standardized dissections of four adult cadavers were performed. Consecutive surgical specimens were examined for evidence of microscopic TDGC disease in the suprahyoid region, measuring the greatest width and length of disease. A retrospective review of all consecutive TGDC procedures was completed., Results: The important surgical landmarks in the suprahyoid area were identified in all cadavers. Microscopic disease in the suprahyoid area was found in 79% (37 of 47) of surgical specimens. The mean greatest length and width of microscopic disease was 12.4 mm and 1.4 mm, respectively. Following identification of these landmarks, the incidence of recurrent or persistent disease decreased (P = .02) from 5% (8 of 159) to 0% (0 of 112)., Conclusion: The majority of pediatric patients with a TGDC will have microscopic disease in the suprahyoid area. The surgical landmark of the fascial plane between the geniohyoid and genioglossus muscles demarcates the anterior and lateral borders of resection in the suprahyoid area. This approach can be used as a reliable and easily reproducible technique in TGDC surgery to increase confidence of achieving complete removal of disease in the suprahyoid area, avoiding persistent or recurrent disease and a revision procedure., Level of Evidence: 4 Laryngoscope, 131:553-558, 2021., (© 2020 The American Laryngological, Rhinological and Otological Society, Inc.)

Gold standard colonoscopy in the UK demands a 90% cecal intubation (CI) rate. Endoscopists must provide photographic evidence of CI, which can include images of the terminal ileum, appendix orifice, anastomosis or ileocecal valve. Whilst photographic proof of intubation should be obtained for all complete colonoscopies, this is not routinely audited. Three hundred and ninety-six complete colonoscopies were analyzed, 200 in an initial audit, and 196 in a second audit. Photos taken during colonoscopy were reviewed for evidence of successful CI, as well as whether these photographs had been marked as "proof of intubation" (POI). Results were shared at departmental governance meetings in order to assess any improvement in practice. Initial audit revealed 70% of colonoscopies had provided sufficient proof of CI but only 50% provided photographs that were described as such. Twenty percent of colonoscopies provided sufficient images, but these were not identified as POI. Thirty percent of all colonoscopies provided insufficient proof of CI. Upon repeat audit, 71% of colonoscopies met best practice standards, with the remaining 29% showing insufficient evidence of CI. In the modern era of digital technology, lack of photographic evidence should be seen as unacceptable and may raise important clinical and medicolegal concerns. We recommend that audits such as this become standard practice to ensure best practice.

Objectives: In 2009, the Food and Drug Administration approved the use of the surgical robotic system for removal of benign and malignant conditions of the upper aerodigestive tract. This novel application of robotic-assisted surgery, termed transoral robotic surgery (TORS), places robotic instruments and camera system through the mouth to reach recessed areas of the pharynx and larynx. Over the successive decade, there was a rapid adoption of TORS with a surgical growth rate that continues to increase. Despite the rapid clinical acceptance, the field of TORS has not yet seen substantive changes or advances in the technical shortcomings, the lack of which has restricted objective TORS-specific surgical skills assessment as well as subsequent skills improvement efforts. One of the primary technical challenges of TORS is operating in a confined space, where the robotic system is maneuvered within the restrictive boundaries of the mouth and throat. Due to these confined boundaries of the pharynx, instruments can frequently collide with anatomic structures such as teeth and bone, producing anatomic collisions. Therefore, we hypothesized that anatomic collisions negatively impact TORS surgical performance. Secondarily, we hypothesized that avoidance of unwanted anatomic collisions could improve TORS surgical proficiency., Methods: Design and fidelity testing for a custom TORS training platform with an integrated anatomic collision-sensing system providing real-time tactile feedback is described. Following successful platform assembly and testing, validation study using the platform was carried through prospective surgical training with trial randomization. Twenty otolaryngology-head and neck surgery residents, each trainee performing three discrete mock surgical trials (n = 60), performed the initial system validation. Ten of the 20 residents were randomized to perform the surgical trials utilizing the real-time feedback system. The remaining 10 residents were randomized to perform the surgical trials without the feedback system, although the system still could record collision data. Surgical proficiency was measured by Global Evaluative Assessment of Robotic Skills (GEARS) score, time to completion, and tumor resection scores (categorical scale ranging 0-3, describing the adequacy of resection)., Results: Major anatomic collisions (greater than 5N of force) negatively affected GEARS robotic skills. A mixed model analysis demonstrated that for every additional occurrence of a major collision, GEARS robotic skills assessment score would decrease by 0.29 points (P = .04). Real-time collision awareness created significantly fewer major (> 5 N) anatomic collisions with the tactile feedback system active (n = 30, mean collisions = 2.9 ± 4.2) as compared with trials without tactile feedback (n = 30, mean collisions = 12.53 ± 23.23) (P < .001). The second assessment measure of time to completion was unaffected by the presence of collisions or by the use of tactile feedback system. The third proficiency assessment was measured with tumor resection grading. Tumor resection scores was significantly (P = .02) improved with collision awareness system activated than trials without collision awareness., Conclusion: In order to test our primary hypothesis, a novel TORS training platform was successfully developed that provides collision force measurements including frequency, severity, and duration of anatomic collisions. Additionally, the platform was modulated to provide real-time tactile feedback of the occurrence of out-of-field collisions. Utilizing this custom platform, our hypothesis that anatomic collisions during TORS diminishes surgical performance was supported. Additionally, our secondary hypothesis that subsequent reduction of anatomic collisions improves TORS proficiency was supported by the surgical trial. Dedicated investigation to characterize the effect size and clinical impact is required in order to translate this finding into training curriculums and into clinical utilization., Level of Evidence: II (Randomized trial) Laryngoscope, 130:S1-S17, 2020., (© 2020 American Laryngological, Rhinological and Otological Society Inc, "The Triological Society" and American Laryngological Association (ALA).)

Objectives: At our institution, in vivo facial nerve mapping (FNM) is used during vascular anomaly (VAN) surgeries involving the facial nerve (FN) to create an FN map and prevent injury. During mapping, FN anatomy seemed to vary with VAN type. This study aimed to characterize FN branching patterns compared to published FN anatomy and VAN type., Study Design: Retrospective study of surgically relevant facial nerve anatomy., Methods: VAN patients (n = 67) with FN mapping between 2005 and 2018 were identified. Results included VAN type, FN relationship to VAN, FNM image with branch pattern, and surgical approach. A Fisher exact test compared FN relationships and surgical approach between VAN pathology, and FN branching types to published anatomical studies. MATLAB quantified FN branching with Euclidean distances and angles. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) analyzed quantitative FN patterns amongst VAN types., Results: VANs included were hemangioma, venous malformation, lymphatic malformation, and arteriovenous malformation (n = 17, 13, 25, and 3, respectively). VAN FN patterns differed from described FN anatomy (P < .001). PCA and HCA in MATLAB-quantified FN branching demonstrated no patterns associated with VAN pathology (P = .80 and P = .91, one-way analysis of variance for principle component 1 (PC1) and priniciple component 2 (PC2), respectively). FN branches were usually adherent to hemangioma or venous malformation as compared to coursing through lymphatic malformation (both P = .01, Fisher exact)., Conclusions: FN branching patterns identified through electrical stimulation differ from cadaveric dissection determined FN anatomy. This reflects the high sensitivity of neurophysiologic testing in detecting small distal FN branches. Elongated FN branches traveling through lymphatic malformation may be related to abnormal nerve patterning in these malformations., Level of Evidence: NA Laryngoscope, 130:2708-2713, 2020., (© 2020 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: The acetabular index and center-edge angle are widely used radiographic parameters. However, the exact landmarks for measuring these parameters are not clearly defined. Although their measurement is straightforward when the lateral osseous margin of the acetabular roof coincides with the lateral end of the acetabular sourcil, where these two landmarks disagree, recommendations have differed about which landmark should be used. Using a radiographic parameter with high reliability for predicting residual hip dysplasia helps avoid unnecessary treatment., Questions/purposes: We aimed to (1) compare two landmarks (the lateral osseous margin of the acetabular roof and the lateral end of the acetabular sourcil) for measuring the acetabular index and center-edge angle with respect to intraobserver and interobserver reliability and the predictability of residual hip dysplasia in patients with developmental dysplasia of the hip (DDH) and (2) evaluate longitudinal change in the acetabular edge's shape after closed reduction with the patient under general anesthesia., Methods: Between February 1985 and July 2006, we performed closed reduction with the patient under general anesthesia as well as cast immobilization in 116 patients with DDH. To be included in this study, a patient had to have dislocated-type DDH. We excluded patients with a hip dislocation associated with neuromuscular disease, arthrogryposis, or congenital anomalies of other organs or systems (n = 9); hips that underwent osteotomy within 1 year since closed reduction (n = 8); hips that underwent open reduction because of re-dislocation after closed reduction (n = 4); and hips with Type III or IV osteonecrosis according to Bucholz-Ogden's classification (n = 4). Ninety-one patients were eligible. We excluded 19% (17 of 91) of the patients, who were lost to follow-up before they were 8 years old, leaving 81% (74 of 91 patients) with full preoperative and most-recent data. Ninety-seven percent (72 patients) were girls and 3% (two patients) were boys. The mean ± standard deviation age was 14.0 months ± 6.4 months (range 3-40 months) at the time of closed reduction and 12.1 years ± 2.3 years (range 8.0-16.0 years) at the time of the latest follow-up examination, the duration of which averaged 11 years ± 2.2 years (range 6.5-15.4 years). To investigate whether longitudinal change in the acetabular edge's shape differed among hips with DDH, contralateral hips, and control hips, we identified control participants after searching our hospital's database for patients with a diagnosis of congenital idiopathic hemihypertrophy from October 2000 to November 2006 who had AP hip radiographs taken at 3 years old and then at older than 8 years. From 29 patients who met these criteria, we randomly excluded two male patients to match for sex because girls were predominant in the DDH group. We excluded another female patient from the control group because of a hip radiograph that revealed unacceptable rotation. Eventually, 26 patients were assigned to the control group. Control patients consisted of 24 girls (92%) and two boys (8%). The demographic characteristics of control patients was not different from those of 67 patients with unilateral DDH, except for laterality (left-side involvement: 64% [43 of 67] in the DDH group versus 38% [10 of 26] in the control group; odds ratio 1.7 [95% confidence interval, 1.0-2.8]; p = 0.035). The acetabular index and center-edge angle at 3 years old were measured using the lateral osseous margin of the acetabular roof (AIB and CEAB) and the lateral end of the acetabular sourcil (AIS and CEAS). The treatment outcome was classified as satisfactory (Severin Grade I or II) or unsatisfactory (Grade III or IV). The intraclass correlation coefficient (ICC) was used to compare the intraobserver and interobserver reliability of each method. We compared the predictability of residual hip dysplasia of each method at 3 years old as a proxy using the area under the receiver operating characteristic (AUC) curve. To evaluate longitudinal change in the acetabular edge's shape, we compared the proportion of hips showing coincidence of the two landmarks between 3 years old and the latest follow-up examination. To investigate whether the longitudinal change in the acetabular edge's shape differs among hips with DDH, contralateral hips, and control hips, we compared the proportion of coincidence among the three groups at both timepoints., Results: Intraobserver and interobserver reliabilities were higher for the CEAB (ICC 0.96; 95% CI, 0.94-0.98 and ICC 0.88; 95% CI, 0.81-0.92, respectively) than for the CEAS (ICC 0.81; 95% CI, 0.70-0.88 and ICC 0.69; 95% CI, 0.55-0.79, respectively). The AIB (AUC 0.88; 95% CI, 0.80-0.96) and CEAB (AUC 0.841; 95% CI, 0.748-0.933) predicted residual hip dysplasia better than the AIS (AUC 0.776; 95% CI, 0.67-0.88) and CEAS (AUC 0.72; 95% CI, 0.59-0.84) (p = 0.03 and p = 0.01, respectively). The proportion of hips showing coincidence of the two landmarks increased from 3 years old to the latest follow-up examination in hips with DDH (37% [25 of 67] to 81% [54 of 67]; OR = 8.8 [95% CI, 3.1-33.9]; p < 0.001), contralateral hips (42% [28 of 67] to 85% [57 of 67]; OR = 16.5 [95% CI, 4.2-141.9]; p < 0.001), and control hips (38% [10 of 26] to 88% [23 of 26]; OR = 14 [95% CI, 2.1-592.0]; p = 0.001). The proportion of coincidence in hips with DDH was not different from that in the contralateral hips and control hips at both timepoints., Conclusions: Measuring the acetabular index and center-edge angle at 3 years old using the lateral osseous margin of the acetabular roof has higher reliability for predicting residual hip dysplasia than that using the lateral end of the acetabular sourcil in patients with DDH treated with closed reduction. Measuring the acetabular index and center-edge angle at an early age using the lateral end of the sourcil may lead to overdiagnosis of residual hip dysplasia and unnecessary treatment., Level of Evidence: Level III, diagnostic study.

Background: We sought to determine the prevalence of common anatomic landmarks around the gallbladder that may be useful in orienting surgeons during laparoscopic cholecystectomy., Methods: The subhepatic anatomy of 128 patients undergoing elective cholecystectomy was recorded. We searched and recorded the presence of five anatomic landmarks: the bile duct (B), the Sulcus of Rouviere (S), the left hepatic artery (A), the umbilical fissure (F), and the duodenum (E). These are the previously described B-SAFE landmarks., Results: We found that the duodenum and umbilical fissure were present reliably in almost all patients. The position of the left hepatic artery could be reliably determined by its pulsation in 84% of patients. A portion of the bile duct could be seen in 77% and the Sulcus of Rouviere was present in 80%. Furthermore, the hepatobiliary triangle was always found superior or at the same level as the Sulcus of Rouviere., Conclusions: We found that these five anatomic landmarks were reliably present. This suggest that using the B-SAFE landmarks may allow a surgeon to more easily orient before and during laparoscopic cholecystectomy and prevent bile duct injuries.

Introduction: Percutaneous dilational tracheostomy (PDT) is a common and increasingly used procedure in the intensive care unit (ICU). It is usually performed with bronchoscopy guidance. Ultrasound has emerged as a useful tool in order to assist PDT, potentially improving its success rate and reducing procedural-related complications., Objective: To investigate whether the ultrasound-guided PDT is equivalent or superior to the bronchoscopy-guided or anatomical landmarks-guided PDT with regard to procedural-related and clinical complications., Methods: A systematic review of randomized clinical trials was conducted comparing an ultrasound-guided PDT to the control groups (either a bronchoscopy-guided PDT or an anatomical landmark-guided PDT) in patients undergoing a PDT in the ICU. The primary outcome was the incidence of major procedural-related and clinical complication rates. The secondary outcome was the incidence of minor complication rates. Random-effect meta-analyzes were used to pool the results., Results: Four studies fulfilled the inclusion criteria and they were analyzed. The studies included 588 participants. There were no differences in the major complication rates between the patients who were assigned to the ultrasound-guided PDT when compared to the control groups (pooled risk ratio [RR]: 0.48; 95% confidence interval [CI]: 0.13-1.71, I 2 = 0%). The minor complication rates were not different between the groups, but they had a high heterogeneity (pooled RR: 0.49; 95% CI 0.16-1.50; I 2 = 85%). The sensitivity analyzes that only included the randomized controlled trials that used a landmark-guided PDT as the control group showed lower rates of minor complications in the ultrasound-guided PDT group (pooled RR: 0.55; 95% CI: 0.31-0.98, I 2 = 0%)., Conclusion: The ultrasound-guided PDT seems to be safe and it is comparable to the bronchoscopy-guided PDT regarding the major and minor procedural-related or clinical complications. It also seems to reduce the minor complications when compared to the anatomical landmark-guided PDT.

Aim: Denonvilliers' fascia is thought to be a multilayered fascial structure, based on its embryological development with the neurovascular bundle embedded within it. Recently, this theory had been proven histologically and by confocal microscopy in many published articles. However, the literature does not report on how surgeons can identify these structures. We aimed to determine the optimal surgical approach for preserving these critical structures., Method: Eighteen cadavers (13 male/five female) were included and treated according to the ethical considerations stated in the donation consent of our institution. Dissection was performed with the assistance of binocular loupes for better anatomical detail. The compositions of the prerectal fascia and the neurovascular bundle were observed and recorded at different levels of dissection using a high-definition camera., Results: The theoretical multilayered fascia was found in male specimens as three fascial layers originating from the perineal body, seminal vesicles and posterior bladder neck. The first layer merged posterolaterally and fused with the rectosacral fascia (Waldeyer's fascia). The neurovascular bundle in male specimens was observed piercing the second and third layers, while the first layer acted as a protective cover. Dissection of female specimens demonstrated only one layer in the prerectal space., Conclusion: Intiating anterior rectal mobilization by incising the peritoneum posterior to its reflection seems to be anatomically correct to preserve DVF. However, its applicability may be difficult in a narrow chanllenging pelvis. The lateral rectal ligaments and Waldeyer's fascia should be dissected from their attachments to the proper fascia of the rectum., (Colorectal Disease © 2019 The Association of Coloproctology of Great Britain and Ireland.)

Aim: Continuity of the mesentery has recently been established and may provide an anatomical basis for optimal colorectal resectional surgery. Preliminary data from operative specimen measurements suggest there is a tapering in the mesentery of the distal sigmoid. A mesenteric waist in this area may be a risk factor for local recurrence of colorectal cancer. This study aimed to investigate the anatomical characteristics of the mesentery at the colorectal junction., Method: In this cross-sectional study, 20 patients were recruited. After planned colorectal resection, the surgical specimens were scanned in a MRI system and subsequently dissected and photographed as per national pathology guidelines. Mesenteric surface area and linear measurements were compared between MRI and pathology to establish the presence and location of a mesenteric waist., Results: Specimen analysis confirmed that a narrowing in the mesenteric surface area was consistently apparent at the rectosigmoid junction. Above the anterior peritoneal reflection, the surface area and posterior distance of the mesentery of the upper rectum initially decreased before increasing as the mesentery of the sigmoid colon. These anatomical properties created the appearance of a mesenteric 'waist' at the rectosigmoid junction. Using the anterior reflection as a reference landmark, the rectosigmoid waist occurred at a mean height of 23.6 and 21.7 mm on MRI and pathology, respectively., Conclusion: A rectosigmoid waist occurs at the junction of the mesorectum and mesocolon, and is a mesenteric landmark for the rectum that is present on both radiology and pathology., (Colorectal Disease © 2019 The Association of Coloproctology of Great Britain and Ireland.)

Introduction: The aim of our study was to elucidate the impact of patients' physical characteristics on the movement of target organs and anatomical landmarks by comparing supine and lateral CT images., Methods: This study consisted of 55 patients who underwent laparoscopic surgery in the lateral position. CT images of the area between the abdomen and pelvis were taken preoperatively with patients in both supine and lateral positions. We measured the moving distance of target organs and anatomical landmarks on the body surface used for access port settings. We investigated which covariates from patients' body composition most affected moving distance in correlation analysis. Then, using multiple linear regression analysis, we examined whether we could predict the movement of target organs and anatomical landmarks solely based on information obtained from supine CT images., Results: The moving distance of both the hilum of the kidney and the outer edge of the rectus abdominis muscle were significantly associated with some physical characteristics. Multiple regression analysis showed that a larger visceral fat area could be a useful index for predicting the movement of the kidney toward the counter side. Lower CT density of back muscles and higher BMI could be useful indexes for predicting the movement of the rectus abdominis muscle., Conclusion: Our results suggested that body composition characteristics obtained from preoperative CT images can help predict the movement of target organs and anatomical landmarks used to determine proper port-site placement for laparoscopic surgery performed with the patient in the lateral position., (© 2019 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.)

Objective: To assess the effect of tranexamic acid on intra-operative bleeding and surgical field visualisation., Methods: Fifty patients undergoing various endoscopic ear surgical procedures, including endoscopic tympanoplasty, endoscopic atticotomy or mastoidectomy, endoscopic ossiculoplasty, and endoscopic stapedotomy, were randomly assigned to: a study group that received tranexamic acid or a control group which received normal saline. The intra-operative bleeding and operative field visualisation was graded using the Das and Mitra endoscopic ear surgery bleeding and field visibility score, which was separately analysed for the external auditory canal and the middle ear., Results: The Das and Mitra score was better (p < 0.05) in the group that received tranexamic acid as a haemostat when working in the external auditory canal; with respect to the middle ear, no statistically significant difference was found between the two agents. Mean values for mean arterial pressure, heart rate and surgical time were comparable in both groups, with no statistically significant differences., Conclusion: Tranexamic acid appears to be an effective haemostat in endoscopic ear surgery, thus improving surgical field visualisation, especially during manipulation of the external auditory canal soft tissues.

Objectives/hypothesis: Augmented reality (AR) allows for the addition of transparent virtual images and video to one's view of a physical environment. Our objective was to develop a head-worn, AR system for accurate, intraoperative localization of pathology and normal anatomic landmarks during open head and neck surgery., Study Design: Face validity and case study., Methods: A protocol was developed for the creation of three-dimensional (3D) virtual models based on computed tomography scans. Using the HoloLens AR platform, a novel system of registration and tracking was developed. Accuracy was determined in relation to actual physical landmarks. A face validity study was then performed in which otolaryngologists were asked to evaluate the technology and perform a simulated surgical task using AR image guidance. A case study highlighting the potential usefulness of the technology is also presented., Results: An AR system was developed for intraoperative 3D visualization and localization. The average error in measurement of accuracy was 2.47 ± 0.46 millimeters (1.99, 3.30). The face validity study supports the potential of this system to improve safety and efficiency in open head and neck surgical procedures., Conclusions: An AR system for accurate localization of pathology and normal anatomic landmarks of the head and neck is feasible with current technology. A face validity study reveals the potential value of the system in intraoperative image guidance. This application of AR, among others in the field of otolaryngology-head and neck surgery, promises to improve surgical efficiency and patient safety in the operating room., Level of Evidence: 2b Laryngoscope, 129:S1-S11, 2019., (© 2019 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: Flexor zone II is defined as the region spanning the proximal aspect of the A1 pulley to the insertion of the flexor digitorum superficialis (FDS) tendon. Descriptions of the FDS insertion are inconsistent in the literature, but zones of injury are frequently determined with reference to superficial landmarks. The purpose of this study was to describe the footprint of the FDS insertion and define its relationship to the proximal interphalangeal (PIP) skin crease., Methods: The FDS insertion on the index, middle, ring, and small fingers was dissected in 6 matched pairs of fresh-frozen cadaveric hands. A Kirschner wire was used to mark the level of the PIP skin crease on bone before measurements of the FDS footprint and its position relative to the PIP skin crease were made using digital calipers., Results: The radial and ulnar FDS slips inserted a mean distance of 3.22 mm from the distal aspect of the PIP skin crease and varied by digit. The mean distal extent of the FDS insertion was 8.29 mm. The mean length of the insertion of each FDS slip was 5.15 mm and the mean width was 1.9 mm., Conclusions: The radial and ulnar FDS slips insert on average 3.22 mm distal to the PIP skin crease and vary by digit. Knowledge of the FDS insertion is clinically relevant when differentiating between flexor zone I and zone II injuries, planning surgical approaches to the finger, and in guiding patient expectations for surgery given the variability in outcome based on zone of injury.

Purpose: The purpose of the present study is to compare newer designs of various symmetric and asymmetric tibial components and measure tibial bone coverage using the rotational safe zone defined by two commonly utilized anatomic rotational landmarks., Methods: Computed tomography scans (CT scans) of one hundred consecutive patients scheduled for total knee arthroplasty were obtained pre-operatively. A virtual proximal tibial cut was performed and two commonly used rotational axes were added for each image: the medio-lateral axis (ML-axis) and the medial 1/3 tibial tubercle axis (med-1/3-axis). Different symmetric and asymmetric implant designs were then superimposed in various rotational positions for best cancellous and cortical coverage. The images were imported to a public domain imaging software, and cancellous and cortical bone coverage was computed for each image, with each implant design in various rotational positions., Results: One single implant type could not be identified that provided the best cortical and cancellous coverage of the tibia, irrespective of using the med-1/3-axis or the ML-axis for rotational alignment. However, it could be confirmed that the best bone coverage was dependent on the selected rotational landmark. Furthermore, improved bone coverage was observed when tibial implant positions were optimized between the two rotational axes., Conclusions: Tibial coverage is similar for symmetric and asymmetric designs, but depends on the rotational landmark for which the implant is designed. The surgeon has the option to improve tibial coverage by optimizing placement between the two anatomic rotational alignment landmarks, the medial 1/3 and the ML-axis. Surgeons should be careful assessing intraoperative rotational tibial placement using the described anatomic rotational landmarks to optimize tibial bony coverage without compromising patella tracking., Level of Evidence: III.

Introduction: Lateral node dissection in rectal cancer has been routinely performed in Eastern countries. Technical and anatomical challenges and potential significant postoperative morbidity associated with the procedure have prevented its implementation into clinical practice in Western countries. However, the minimally invasive approach may offer the opportunity of performing this complex procedure with precise anatomical dissection and minimal intraoperative blood loss. In this setting, proper training and standardization of technical steps is highly warranted for surgeons not fully acquainted with the procedure., Technique: Access to the lateral nodes along the obturator and internal iliac vessels is described by using specific anatomical landmarks. Opening of the peritoneum along the ureter provides access to the region of interest. Dissection of the medial limit is performed preserving the neurovascular bundle and ureter. The lateral dissection is performed along the external iliac vein to provide access to the obturator muscle. Identification of the obturator nerve with blunt dissection of the fat is a critical part of the procedure. Once the lymphatic connections between the inguinal and iliac nodes are transected, dissection is performed along the internal iliac vessels, and branches are separated from the lymphadenectomy specimen., Results: Evidence supports that lateral node dissection performed for highly selected patients with minimally invasive access leads to less intraoperative blood loss and similar oncological outcomes. Technical steps illustrated in the present video may aid surgeons in performing this procedure with precise anatomical landmarks and minimal risk for intraoperative complications., Conclusions: Lateral node dissection for rectal cancer is a procedure that may follow standardized technical steps by using precise anatomical landmarks with the use of minimally invasive approach.

Background: A well-reduced femoral neck fracture is more likely to heal than a poorly reduced one, and increasing the quality of the surgical exposure makes it easier to achieve anatomic fracture reduction. Two open approaches are in common use for femoral neck fractures, the modified Smith-Petersen and Watson-Jones; however, to our knowledge, the quality of exposure of the femoral neck exposure provided by each approach has not been investigated., Questions/purposes: (1) What is the respective area of exposed femoral neck afforded by the Watson-Jones and modified Smith-Petersen approaches? (2) Is there a difference in the ability to visualize and/or palpate important anatomic landmarks provided by the Watson-Jones and modified Smith-Petersen approaches?, Methods: Ten fresh-frozen human pelvi underwent both modified Smith-Petersen (utilizing the caudal extent of the standard Smith-Petersen interval distal to the anterosuperior iliac spine and parallel to the palpable interval between the tensor fascia lata and the sartorius) and Watson-Jones approaches. Dissections were performed by three fellowship-trained orthopaedic traumatologists with extensive experience in both approaches. Exposure (in cm) was quantified with calibrated digital photographs and specialized software. Modified Smith-Petersen approaches were analyzed before and after rectus femoris tenotomy. The ability to visualize and palpate seven clinically relevant anatomic structures (the labrum, femoral head, subcapital femoral neck, basicervical femoral neck, greater trochanter, lesser trochanter, and medial femoral neck) was also recorded. The quantified area of the exposed proximal femur was utilized to compare which approach afforded the largest field of view of the femoral neck and articular surface for assessment of femoral neck fracture and associated femoral head injury. The ability to visualize and palpate surrounding structures was assessed so that we could better understand which approach afforded the ability to assess structures that are relevant to femoral neck fracture reduction and fixation., Results: After controlling for age, body mass index, height, and sex, we found the modified Smith-Petersen approach provided a mean of 2.36 cm (95% confidence interval [CI], 0.45-4.28 cm; p = 0.015) additional exposure without rectus femoris tenotomy (p = 0.015) and 3.33 cm (95% CI, 1.42-5.24 cm; p = 0.001) additional exposure with a tenotomy compared with the Watson-Jones approach. The labrum, femoral head, subcapital femoral neck, basicervical femoral neck, and greater trochanter were reliably visible and palpable in both approaches. The lesser trochanter was palpable in all of the modified Smith-Petersen and none of the Watson-Jones approaches (p < 0.001). All modified Smith-Petersen approaches (10 of 10) provided visualization and palpation of the medial femoral neck, whereas visualization of the medial femoral neck was only possible in one of 10 Watson-Jones approaches (p < 0.001) and palpation was possible in eight of 10 Watson-Jones versus all 10 modified Smith-Petersen approaches (p = 0.470)., Conclusions: In the hands of surgeons experienced with both surgical approaches to the femoral neck, the modified Smith-Petersen approach, with or without rectus femoris tenotomy, provides superior exposure of the femoral neck and articular surface as well as visualization and palpation of clinically relevant proximal femoral anatomic landmarks compared with the Watson-Jones approach., Clinical Relevance: Open reduction and internal fixation of a femoral neck fracture is typically performed in a young patient (< 60 years old) with the objective of obtaining anatomic reduction that would not be possible by closed manipulation, thus enhancing healing potential. In the hands of surgeons experienced in both approaches, the modified Smith-Petersen approach offers improved direct access for reduction and fixation. Higher quality reductions and fixation are expected to translate to improved healing potential and outcomes. Although our experimental results are promising, further clinical studies are needed to verify if this larger exposure area imparts increased quality of reduction, healing, and improved outcomes compared with other approaches. The learning curve for the exposure is unclear, but the approach has broad applications and is frequently used in other subspecialties such as for direct anterior THA and pediatric septic hip drainage. Surgeons treating femoral neck fractures with open reduction and fixation should familiarize themselves with the modified Smith-Petersen approach.

When cochlear implantation was first introduced, the mastoidectomy and posterior tympanotomy approach was the most frequently used technique to gain access to the middle ear and the cochlea. Since 2000, several authors have routinely used a non-mastoidectomy nonposterior tympanotomy technique, which has undergone several modifications. Alternative surgical techniques for cochlear implantation have recently been introduced, such as endomeatal-alone or suprameatal-alone and combined posterior tympanotomy/endomeatal approaches. The goal of this study was to describe another modification of this less invasive technique to perform cochlear implantation. Cochlear implantations were performed between January 1, 2002, and December 31, 2012, in 220 patients through the posterior suprameatal approach. In reviewing our experiences, we have concluded that this approach, which eliminates the need for mastoidectomy, is considered safe, time-efficient, and minimally invasive. The possible pitfalls and the microsurgical relevance of anatomic structures of this technique are discussed in detail. Using this technique, not all classical anatomic orientation points are identified. However, certain landmarks predict the depth and the three-dimensional location of invisible anatomic structures.

Introduction: This study was designed to quantify the important anatomical landmarks and the path of the inferior alveolar nerve (IAN) within the human mandibular body and ramus, in particular with reference to the bilateral sagittal split osteotomy (BSSO)., Materials and Methods: Four hundred and eleven CT scans were studied, 299 of these were involved in determining the position of lingula; and 230 were involved in determining the course of IAN in the mandibular molar region, namely from the mesial of the mandibular first molar to the distal of the mandibular second molar; 118 were involved with both measurements., Results: On average, the lingula was located 17.0 ± 2.2 mm from the external oblique ridge; 11.6 ± 2.0 mm from the internal oblique ridge; 17.2 ± 2.7 mm from the sigmoid notch; and 15.6 ± 1.9 mm from the posterior border of the mandible. The course of the IAN in the mandibular molar region was found to descend vertically from the distal of the mandibular second molar (7) to reach its lowest point between the first and second molars (6 and 7), and then ascend towards the mesial of the first molar (6). Horizontally, the IAN was found to traverse medially between the distal of the 7 and the middle of the 7, and then changes its path laterally towards the mesial of the 6., Conclusion: Precise knowledge of the individual's position of the IAN will help surgical planning.

Background: A critical step in the far lateral approach (FLA) is exposure of the V3 segment of the vertebral artery, located deep in the suboccipital triangle (SOT). Safe exposure of the SOT is achieved by means of a plane-by-plane dissection, which carries the risk of devascularization. A suitable alternative is to lift a cutaneous muscle flap including the 3 first muscle planes and leave the deepest plane (SOT) attached to the skull base. To achieve this, it is necessary to have superficial anatomic landmarks to help identify the cleavage site. We describe the use of the nuchal lines as a safe, effective, and reproducible method to dissect the muscles to expose the SOT and vertebral artery., Methods: Eight adult cadaveric heads, fixed with formaldehyde and injected, were studied. On both sides, FLA was simulated by using the nuchal lines as anatomic landmarks to expose the SOT. This technique was later applied on 10 patients requiring FLA., Results: Anatomic dissections confirmed identification, by means of the nuchal lines, of a cleavage site, which made it possible to separate the deepest muscle plane from the rest of the flap. This technique was successfully applied in 10 patients undergoing FLA., Conclusions: The nuchal lines allow dissection of muscles in 2 groups, one superficial and the other deep (SOT), which remains attached to the skull base. The V3 segment of the vertebral artery is easily exposed., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Intraosseous access is a method for providing vascular access in resuscitation of critically ill and injured patients when traditional intravenous access is difficult or impossible. There is a lack of detailed description for the landmark for the insertion point in the literature. The aim of this study was to determine the exact location for intraosseous access. Radiographic computed tomography (CT) images of a total of 50 dry tibia bones were obtained. With 5-mm intervals, for all transverse images and by selecting transverse section, measurements were taken from the thickness of the cortex at anterior margin and mid-line medial surface, distance from anterior margin, and mid-line medial surface of the tibia to the posterior wall of medullar cavity, distance from anterior margin and mid-line medial surface of the tibia to the posterior surface of the tibia. The thinner part of the cortex of the tibia and the larger width of the medullar cavity is at 0.5 cm below the tibial tuberosity in the midline of the medial surface. The application region for proximal tibia access and landmark and most suitable insertion point for intraosseous infusion should be at level 0.5 cm below the tibial tuberosity in the midline of the medial surface. It was recommended that standard length for intraosseous canule should be 17 mm except for the thickness of skin. In conclusion, presented study provides certain localization for intraosseous access and standard length for intraosseous canule and this will be more effective in using this technique. Clin. Anat. 31:593-597, 2018. © 2017 Wiley Periodicals, Inc., (© 2017 Wiley Periodicals, Inc.)

Study Design: Comparison, in terms of insertion accuracy and biomechanical performance, between an increased cortical purchase and straightforward pedicle screw trajectory., Objective: This study aims to compare a trajectory with increased cortical purchase to the more common straightforward trajectory in terms of strength and insertion accuracy using real-time navigation., Summary of Background Data: In previous studies, it was suggested that pedicle screw pullout strength is strongly correlated with bone mineral density, and using a more cortical tract allows a greater portion of the denser bone, the cortex, to be in contact with the screw. In light of this advantage, an insertion technique has been proposed more recently, to increase the cortical purchase to maximize screw thread contact with cortical bone. It is performed inserting the screw with reduced transverse inclination and results in cortical bone purchase in the lateral portion of the pedicle., Methods: Eight T1 and eight T3 vertebra models were reconstructed in Mimics Suite (Materialise, Leuven, Belgium) using CT data obtained with a Medtronic O-arm. Using a previously developed computer algorithm, we calculated all achievable safe trajectories for pedicle screw placement ensuring a minimal distance of 0.5 mm between screw and pedicle edges. For both vertebrae, among these, the straightest and the most convergent trajectories with the calculated insertion region greater than 15% of the total were selected to safely instrument the vertebrae, respectively, as ICP and straightforward techniques. The straightforward technique was planned with a transverse angle of 22.50° in both vertebrae whereas the ICP was planned with a transverse angle of 12.50° for T1 and 2.5° for T3. The screws were implanted by a surgeon experienced in straightforward insertion, and other independent investigators measured placement accuracy and mechanical performance., Results: The transverse screw angles for T1 and T3 with straightforward technique had average values of 24.93° ± 2.96° and 23.53° ± 2.70°, respectively. For the ICP technique, the average values were 15.60° ± 2.95° for T1 and 2.29° ± 1.55° for T3. The resultant errors associated with screw placement for T1 and T3 were not significantly different (p > .05). The pullout failure loads with straightforward techniques ranged from 756 ± 164 N in T1 to 703 ± 74 N in T3 and were not significantly different (p > .05) from the values of 699 ± 84 N for T1 and of 732 ± 113 N measured for the ICP., Conclusions: For the upper thoracic vertebrae tested, despite the use of shorter screws, the insertion technique with increased cortical purchase, in biomechanical terms, is comparable with the straightforward trajectory. Using guidance, the proposed ICP technique was performed with the same accuracy as the popular straightforward technique., Level of Evidence: Level V., (Published by Elsevier Inc.)

Background: Diseases of the orbit represent a surgical challenge, particularly those compromising the orbital apex. Optimal surgical access should provide the best possible exposure, allowing to identify certain key anatomical structures, called landmarks., Objective: Describe the endoscopic anatomy of the structural unit formed by the Inferior Orbital Fissure (IOF) and the Müller’s muscle (MM) at the orbital apex (OA), thus generating a new endoscopic anatomical landmark., Materials and Methods: A bone-descriptive analysis of the IOF in dry craniums, was followed by dissection and endoscopic study of six heads (twelve sides), colored and fixed in formaldehyde. In ten dry craniums (twenty sides), distances and angles of OA foramina were measured (optic foramen [OF] and foramen rotundum [FR]). Statistical analysis was performed with SPSS 17.0 statistical software (SPSS, Inc. Chicago, IL)., Results: The structural unit IOF-MM was identified in all endoscopic dissections, verifying its intimate relationship with the OA. From the morpho-metric standpoint, OF and FR were found at an average distance of 65.19 mm and 60.16 mm, respectively. The average angle of the OF was 13.32 degrees, whereas the one for FR was 19.31 degrees. We found a significant correlation between OF and FR only on the left side (left hemi-crane) (Kendall Tau b 0.69, p=0.006). There were no anatomical or morphological differences between both sides., Conclusion: The unit IOF-MM is a constant anatomical landmark, useful and safe under endoscopic technique, which allows the recognition of the OA and its contiguous areas.

Background: The V2 segment of the vertebral artery (VA) typically runs through the transverse foramen of C2-C6. V2 injury may occur during anterior approaches to the cervical spine and can cause significant morbidity. We describe landmarks and microsurgical V2 repair techniques through the standard anterolateral cervical diskectomy approach., Methods: Five silicone-injected cadaveric heads (necks-C7) were dissected bilaterally. An anterolateral approach with C3-4, C4-5, and C5-6 diskectomies and an ipsilateral VA injury were simulated. VA approach and repair were performed using microdissection techniques. Landmarks to the VA were identified, and distances from landmarks to the VA were measured in horizontal and vertical planes. Operative photographs of stepwise approach and repair techniques were processed for stereoscopic illustration. An illustrative case describes microsurgery to successfully repair an inadvertent VA injury during a C3-C6 diskectomy and fusion procedure., Results: The anatomic landmarks delineated were the intervertebral disk, uncinate apices, and anterior tubercles of C4-C6 transverse processes. After temporary hemostasis with packing, VA exposure and repair included dissection of the longus colli muscle, removal of the anterior root of the transverse processes above and below the injury level, intertransversarii muscle removal, vertebral plexus opening, VA handling, and microsuturing. In 30 dissected cadaver intertransverse intervals, 13 medial, 7 lateral, and 3 anterior branches of the V2 were encountered at C3-C6 levels., Conclusion: Familiarity with relevant vascular surgical anatomy allows neurosurgeons to be prepared in cases of VA injury and may facilitate repair when the VA is injured during anterior cervical spine surgery., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Residual impingement resulting from insufficient resection of bone during the index femoroplasty is the most-common reason for revision surgery in patients with cam-type femoroacetabular impingement (FAI). Development of surgical resection guidelines therefore could reduce the number of patients with persistent pain and reduced ROM after femoroplasty., Questions/purposes: We asked whether removal of subchondral cortical bone in the region of the lesion in patients with cam FAI could restore femoral anatomy to that of screened control subjects. To evaluate this, we analyzed shape models between: (1) native cam and screened control femurs to observe the location of the cam lesion and establish baseline shape differences between groups, and (2) cam femurs with simulated resections and screened control femurs to evaluate the sufficiency of subchondral cortical bone thickness to guide resection depth., Methods: Three-dimensional (3-D) reconstructions of the inner and outer cortical bone boundaries of the proximal femur were generated by segmenting CT images from 45 control subjects (29 males; 15 living subjects, 30 cadavers) with normal radiographic findings and 28 nonconsecutive patients (26 males) with a diagnosis of cam FAI based on radiographic measurements and clinical examinations. Correspondence particles were placed on each femur and statistical shape modeling (SSM) was used to create mean shapes for each cohort. The geometric difference between the mean shape of the patients with cam FAI and that of the screened controls was used to define a consistent region representing the cam lesion. Subchondral cortical bone in this region was removed from the 3-D reconstructions of each cam femur to create a simulated resection. SSM was repeated to determine if the resection produced femoral anatomy that better resembled that of control subjects. Correspondence particle locations were used to generate mean femur shapes and evaluate shape differences using principal component analysis., Results: In the region of the cam lesion, the median distance between the mean native cam and control femurs was 1.8 mm (range, 1.0-2.7 mm). This difference was reduced to 0.2 mm (range, -0.2 to 0.9 mm) after resection, with some areas of overresection anteriorly and underresection superiorly. In the region of resection for each subject, the distance from each correspondence particle to the mean control shape was greater for the cam femurs than the screened control femurs (1.8 mm, [range, 1.1-2.9 mm] and 0.0 mm [range, -0.2-0.1 mm], respectively; p < 0.031). After resection, the distance was not different between the resected cam and control femurs (0.3 mm; range, -0.2-1.0; p > 0.473)., Conclusions: Removal of subchondral cortical bone in the region of resection reduced the deviation between the mean resected cam and control femurs to within a millimeter, which resulted in no difference in shape between patients with cam FAI and control subjects. Collectively, our results support the use of the subchondral cortical-cancellous bone margin as a visual intraoperative guide to limit resection depth in the correction of cam FAI., Clinical Relevance: Use of the subchondral cortical-cancellous bone boundary may provide a method to guide the depth of resection during arthroscopic surgery, which can be observed intraoperatively without advanced tooling, or imaging.

Objective: The anatomic area exposed through exposure of Trautmann triangle may not be sufficient. We studied the additional exposure provided by skeletonizing the sigmoid sinus (SS)., Methods: In 5 human cadaveric heads, thin-cut computed tomography images of 2 sides of the temporal bone were obtained for a total of 10 sides. The estimated surgical working angle was calculated based on the relationship of the SS to the posterior semicircular canal (PSC), superior petrosal sinus, and jugular bulb on imaging. Mastoidectomy was performed, and heads with and without SS skeletonization were remeasured., Results: Working angle calculated on computed tomography was 56° ± 11.3. Skeletonization of the SS increased the distance between the PSC and SS by 5 mm (P = 0.01) and between the lateral semicircular canal and SS by 4 mm (P = 0.01). Skeletonization and retraction of the SS significantly increased the distance between the PSC and lateral semicircular canal to the SS. On images obtained after mastoidectomy, skeletonizing the SS helped improve anterior visibility on most samples that had an SS that was lateral to the PSC on axial imaging. In samples in which the SS was medial to the PSC or had only minimal lateral displacement, skeletonizing the SS did not markedly improve visibility of the retrolabyrinthine space., Conclusions: Working area and visibility improved as the PSC and SS approached the same plane on axial imaging. Preoperative evaluation of the laterality of the SS to the PSC may assist a surgeon in determining the need for skeletonizing the SS and avoiding possible vascular injuries., (Copyright © 2017 Elsevier Inc. All rights reserved.)

The authors performed cadaveric dissections to investigate the existence of an anatomical structure creating and maintaining the cervical mental angle, aiming to understand the anatomical bases of the cervico-mental angle and its modifications over time. Six fresh cadaver dissections were performed; four were done in the Caen University anatomy laboratory one in Paris XV University and one in the Coventry University hospital, England. At the end of this investigation, the authors were able to demonstrate the existence of an anatomical structure in the neck, the cervico-mental angle suspensory ligament. This ligament that fixates the platysma and skin to deeper structures originated from the second branchial arch and seems to play a key role in the formation of the cervico-mental angle and in the anatomical alterations in the ageing process., Level of Evidence V: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

This is a commentary and discussion in response to a cadaveric study entitled, "Cervico-mental angle suspensory ligament: The keystone to understand the cervico-mental angle and the aging process of the neck." While highlighting the cervico-mental angle suspensory ligament has the potential to give rise to new surgical technique in neck rejuvenation surgery, the authors caution readers of the study's major limitation. Without well-documented results aligning with aesthetic ideals or reports of the safety and longevity of the procedure, it seems too early to consider this ligament the keystone to understand the aging neck. An actual surgical technique must be described and further clinical studies need to be performed before this ligament can be included in the armamentarium of neck rejuvenation surgery. As the goal of surgery should be a natural result that restores aesthetic ideals of the youthful neck, regardless of the significance that this ligament will carry, its application should be tailored to the patient to avoid overly aggressive treatment. Level of evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Objective: The looped thread carpal tunnel release (TCTR) procedure is a minimally invasive percutaneous technique performed under ultrasound (US) to transect the transverse carpal ligament in patients with carpal tunnel syndrome. Study objectives were to evaluate the accuracy of identifying key US landmarks, safety, effectiveness, and technical difficulty of TCTR., Design: Fourteen lightly embalmed cadaveric distal forearm-hand specimens were subject to US identification of key landmarks, TCTR procedure, and post-TCTR dissection. Outcome measures of interest were (1) correspondence between key landmarks (median nerve and 4 bony pillars of transverse carpal ligament) identified on US and anatomical structures exposed by dissection, (2) percentage of the transverse carpal ligament transected and location of the transection, (3) frequency of damage to adjacent structures, (4) time to complete procedure, and (5) operator assessment of technical difficulty of each TCTR procedure (0 = extremely easy, 10 = extremely difficult)., Results: (1) Skin markings delineating the position of US-visualized landmarks corresponded almost perfectly to anatomical dissection. (2) Nine (64.2%) of 14 specimens had complete division of the transverse carpal ligament. In the remaining 5 specimens, an average of 68.8% of the ligament was transected. (3) No adjacent structures were damaged. (4) Time to complete the procedure was on average 9.9 ± 4.6 minutes. (5) Average procedural difficulty was 4.3/10., Conclusions: Thread carpal tunnel release is potentially a safe, quick, and effective procedure to transect the transverse carpal ligament. Future clinical investigation is recommended.

Purpose: The purpose of our study was to compare the accuracy of the rotational position of the femoral component in total knee arthroplasty aligned with patient individualized jigs (PSJ) to a gap balancing technique (GBT)., Methods: A consecutive series of 21 osteoarthritic patients were treated with 22 cruciate-retaining total knee prostheses. During surgery, the rotation of the femoral component pinholes was recorded for all knees using PSJ and GBT and transferred to computer tomograms (CT). The rotational differences between PSJ and GBT relative to the transepicondylar axis were analysed., Results: The medium rotation of the femoral component pinholes was 1.3° ± 5.1° (min = -6.3°; max = 14.4°) for PSJ and 0.1 ± 1.4° (min = -1.6°; max = 3.4°) for GBT. Outliers of more than 3° were found more frequently with PSJ in 12 cases but only in one for GBT., Conclusion: Based on our study, we would not recommend relying intra-operatively solely on the CT-based PSJ without the option to adjust or control femoral rotation., Level of Evidence: II.

The risk of urethral injury during transanal total mesorectal excision (taTME) is delineated, and potential risk factors for iatrogenic transection are reviewed. A variety of applied and theoretical techniques can be used by surgeons to diminish the risk of injury in males undergoing this operation. Many of the approaches utilize non-optic media and wavelengths beyond the visible light spectrum which can enhance the surgeon's frame of reference. The aim of the present study was to assess the techniques and theoretical approaches to urethral localization during taTME. Future directions in surgical imaging are also discussed, including the use of organic dyes, quantum dots, and carbon nanotubes; collectively, technology that could someday provide surgeons with an ability to identify anatomic structures prone to injury.

Objective To define relationships between the frontal sinus opening, ostia of other frontal recess cells, and endoscopic landmarks and to develop a clinically useful framework to guide frontal sinus surgery. Study Design Retrospective review. Setting Tertiary care academic referral center. Methods Adult patients with computed tomography (CT) without sinonasal pathology were included. Virtual endoscopy (using OsiriX) and corresponding CT reconstructions were used to identify all visible ostia in the frontal recess and characterize their positions in spaces between the uncinate/agger nasi (U), bulla ethmoidalis (EB), and middle turbinate (MT). Results Two hundred sides in 100 patients (median age 51 years, 62% female) were analyzed. The "center" of each map was defined as the intersection of spaces between U, EB, and MT. The frontal sinus opening was in the "center" in 53% of frontal recesses, lateral to this position in 29%, and anterior in 11%. When the frontal sinus opening was at the "center," anterior ostia drained frontal Kuhn T cells in 51% and intersinus septal cells in 23%. The skull base attachment of the apical strut of the uncinate process demarcated medial and lateral within the space between U and EB, with the opening to the frontal sinus medial in 68% and lateral in 31%. Left-right asymmetry in frontal sinus openings was noted in 46% of patients. Conclusion Combining preoperative imaging and knowledge of these anatomic relationships may facilitate more efficient frontal outflow tract identification and instrumentation. This represents the first and largest description of ostial configurations relative to endoscopic structural landmarks., Level of Evidence: 4.

Purpose: Total disc arthroplasty can be a viable alternative to fusion for degenerative disc disease of the lumbar spine. The correct placement of the prosthesis within 3 mm from midline is critical for optimal function. Intra-operative radiographic error could lead to malposition of the prosthesis. The objective of this study was first to measure the effect of fluoroscopy angle on the placement of prosthesis under fluoroscopy. Secondly, determine the visual accuracy of the placement of artificial discs using different anatomical landmarks (pedicle, waist, endplate, spinous process) under fluoroscopy., Methods: Artificial discs were implanted into three cadaver specimens at L2-3, L3-4, and L4-L5. Fluoroscopic images were obtained at 0°, 2.5°, 5°, 7.5°, 10°, and 15° from the mid axis. Computerized tomography (CT) scans were obtained after the procedure. Distances were measured from each of the anatomic landmarks to the center of the implant on both fluoroscopy and CT. The difference between fluoroscopy and CT scans was compared to evaluate the position of prosthesis to each anatomic landmark at different angles., Results: The differences between the fluoroscopy to CT measurements from the implant to pedicle was 1.31 mm, p < 0.01; implant to waist was 1.72 mm, p < 0.01; implant to endplate was 1.99 mm, p < 0.01; implant to spinous process was 3.14 mm, p < 0.01. When the fluoroscopy angle was greater than 7.5°, the difference between fluoroscopy and CT measurements was greater than 3 mm for all landmarks., Conclusions: A fluoroscopy angle of 7.5° or more can lead to implant malposition greater than 3 mm. The pedicle is the most accurate of the anatomic landmarks studied for placement of total artificial discs in the lumbar spine.

Introduction and Hypothesis: To describe the relationships between pelvic bony landmarks to points along the third sacral nerve and to uterosacral ligament suspension sutures., Methods: Three transvaginal uterosacral ligament suspension sutures were placed bilaterally in unembalmed female human cadavers. The third sacral nerve was marked at the foramen (S3a) and at two additional points at 1-cm intervals along its course caudally (S3b, S3c). Three bony pelvic landmarks were identified and marked, including the ischial spine, pubic symphysis, and coccyx. Distances from each landmark to each suture and nerve point were measured. The distance from each landmark to each S3 nerve point was extended radially, encompassing an arbitrary zone in which sutures may be placed and thus where nerve injury may occur. Zones of potential nerve injury included: zone A (closest to the sacral nerve root), zone B, and zone C (closest to the landmark). Descriptive statistics were used and comparisons were made using Student's t test and ANOVA., Results: Ten cadaver specimens were dissected. For the ischial spine, the distances to points S3a, S3b, and S3c were 6.3, 5.4, and 4.6 cm respectively. Approximately two thirds of the sutures were noted beyond zone C, indicating a potentially increased risk of nerve injury with suture placement in zones farthest from the ischial spine given their proximity to the sacral nerve., Conclusions: Using the ischial spine as a landmark, increased sacral nerve injury could result from suture placement beyond the mean distance of 4.6 cm from the ischial spine. The use of bony landmarks in avoiding sacral nerve injury may be as important as suture depth and angle of suture placement.

Background: For shoulder arthroscopy, few anatomical landmarks are available and inexperienced surgeons tend to be adrift due to the limited visual field of the scope. The purpose of this study was to demonstrate the useful landmarks around the glenoid for accurate orientation, and also the safe distance to avoid suprascapular nerve injury during surgical procedures around the glenoid., Methods: In 15 human solution-fixed cadavers, a cross-section of the shoulder joint on the labrum surface was created. The positions of the principal anatomical structures surrounding the glenoid were marked on the labrum and measured using our clock face indication system. In 9 shoulders the distances from the labral surface to the spinoglenoid notch were recorded. As an indicator of the scapula size, the distances between the superior and inferior angles of the scapula were also measured., Results: The average landmark positions in the right shoulder were as follows: center of the attachment of the long tendon 11:59, anterior edge of the supraspinatus 11:59, posterior edge of the base of the coracoid process 12:13, superior edge of the subscapularis 1:03, anterior edge of the base of the coracoid process 1:25, inferior edge of the subscapularis 5:27, inferior edge of the teres minor 6:21, border of the infraspinatus and teres minor 7:43, center of the scapula spine 10:06, border of the supra and infraspinatus 10:27. The average distance from the labral surface to the spinoglenoid notch was 23.17 mm, and that from the superior to inferior angle was 144.93 mm. The Pearson correlation coefficient for these distances was 0.007., Conclusions: The locations of anatomical landmarks surrounding the glenoid were reliably demonstrated using our clock face indication system. The expected distance from the labral surface to the suprascapular nerve was approximately 23 mm, irrespective of the size of the scapula., (Copyright © 2016 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Purpose: Transanal total mesorectal excision (taTME) requires specific technical expertise, as it is often difficult to ascertain the correct dissection plane. Consequently, one can easily enter an incorrect plane, potentially resulting in bleeding (sidewall or presacral vessels), autonomic nerve injury and urethral injury. We aim to demonstrate specific visual features, which may be encountered during surgery and can guide the surgeon to perform the dissection in the correct plane., Method: Specific features of dissection in the correct and incorrect planes are demonstrated in the accompanying video., Results: The 'triangles' created using appropriate traction can aid in performing a precise dissection in the correct plane. Recognition of features described as 'O's can alert surgeons that they are entering a new fascial plane and can avoid incursion into an incorrect plane., Conclusion: Understanding and recognizing the described features which can be encountered in taTME surgery, a safe and accurate TME dissection can be facilitated.

Objective: Knowledge of the course of the vertebral artery during instrumentation is of paramount importance. It has been shown that erosion of the C2 pedicle and body can occur due to pulsations of the adjacent vertebral artery. This often results in a "cave" for this segment of the artery. The descriptions of this anatomy are limited. The current study was performed with the hope that these data will be of use to spine surgeons during C2 instrumentation., Methods: In 40 human adult C2 bone specimens, the position of the vertebral artery in relation to the undersurface of the superior articular facet, pedicle, and C2 body was observed. A classification system was used to better describe these relationships. Pedicle screws were then placed into selected examples of each type., Results: We found type 0 specimens, with no cave, on 8 sides (10%). Types I, II, and III caves with minimal, moderate, and significant encroachment of the pedicle were observed on 40%, 35%, and 27.5% sides, respectively. Type IV caves with erosion into the lateral C2 body and undersurface of the superior articular facet were observed on 12.5% of sides. Although larger caves were found on left sides, this did not reach statistical significance. Pedicle screw placement for types III and IV were most likely to enter the vertebral artery cave (P < 0.05)., Conclusions: Additional osteologic data regarding the course of the vertebral artery while within C2 may decrease morbidity during surgery in this region., (Copyright © 2016 Elsevier Inc. All rights reserved.)