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Background: Injection cosmetics have become popular in recent years. The nasolabial fold is one of the most important and dangerous regions in the midface, and its three-dimensional relationship with the facial artery remains unclear., Methods: Fifty-two cadavers infused with lead oxide contrast medium via the external carotid arteries were scanned by computed tomography (CT). The three-dimensional model was reconstructed using Mimics and Origin software, and the relevant data were calculated using validated algorithms., Results: There were three facial artery types according to its course in relation to the nasolabial fold. In the most common type, accounting for 83.7% of specimens, the facial artery evolves into an angular artery, with a horizontal distance between facial artery and nasolabial fold of - 1.90 ± 2.40, - 3.90 ± 2.95, - 5.18 ± 3.42, - 5.59 ± 3.53, - 5.59 ± 3.83, - 6.07 ± 4.10, - 6.92 ± 3.70, - 6.79 ± 3.37, - 4.52 ± 3.20, and - 2.76 ± 3.60 (mm) from the nasal ala to the oral commissure and a vertical distance of - 4.03 ± 2.56, - 3.27 ± 2.27, - 2.81 ± 2.57, - 2.1 ± 2.64, - 1.5 ± 3.32, - 0.71 ± 3.99, 0.92 ± 4.43, 0.4 ± 5.31, - 4.14 ± 5.14, - 7.05 ± 4.74 (mm)., Conclusions: The facial artery is vulnerable to damage when injecting filler in the nasolabial fold. For the upper 1/3 of the nasolabial fold, the supraperiosteal layer is recommended for injection, while for the lower 2/3 of the nasolabial fold, the dermal layer along the nasolabial fold is recommended., Level of Evidence Iv: 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 ., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Background: Lip filler injection is one of the most common minimally invasive cosmetic procedures involving the face; however, vascular complications are not uncommon. The aim of this study was to investigate the anatomy of the superior labial artery (SLA) and provide precise topographic information for dermal filler injection into the lips., Methods: Computed tomography (CT) scans of 52 cadaveric heads injected with lead oxide were obtained. We then used Mimics software to construct 3D images of the SLA described by a coordinate system based on the bilateral external auditory canal and the left orbit. This study aimed to classify the SLA in the Han Chinese population, measure its diameter at specific points, and determine the thickness of the lip at those points. Ultimately, we utilized a thermal imaging technique to illustrate the course and depth of the SLA within the lip. The objective of this study was to provide safe guidance for clinical injections., Results: In this study, the SLA was successfully identified in all cadavers. The mean overall diameter of the superior labial arteries was 1.36 ± 0.28 mm. The superior labial artery showed a general course from deep to shallow with an average depth of 5.68 ± 1.68 mm from the oral commissure to the midline., Conclusions: There are anatomical differences in the superior labial arteries among Chinese people. Furthermore, 3D CT images can digitally elucidate the exact positions of the superior labial artery via a coordinate system, improving the safety of upper lip filler injections in clinical settings., Level of Evidence Iv: 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 ., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Purpose: Screwed anterior lumbar interbody fusion (SALIF) alleviates the need for supplemental posterior fixation leading to reduction of perioperative morbidity. Specifically, elderly and multimorbid patients would benefit from shorter operative time and faster recovery but tend to have low bone mineral density (BMD). The current study aimed to compare loosening, defined as increase of ROM and NZ, of SALIF versus transforaminal lumbar interbody fusion (TLIF) under cyclic loading in cadaveric spines with reduced BMD., Methods: Twelve human spines (L4-S2; 6 male 6 female donors; age 70.6 ± 19.6; trabecular BMD of L5 84.2 ± 24.4 mgHA/cm 3 , range 51-119 mgHA/cm 3 ) were assigned to two groups. SALIF or TLIF were instrumented at L5/S1. Range of motion (ROM) and neutral zone (NZ) were assessed before and after axial cyclic loading (0-1150 N, 2000 cycles, 0.5 Hz) in flexion-extension (Flex-Ext), lateral bending, (LB), axial rotation (AR)., Results: ROM of the SALIF specimens increased significantly in all loading directions (p ≤ 0.041), except for left AR (p = 0.053), whereas for TLIF it increased significantly in left LB (p = 0.033) and Flex (p = 0.015). NZ of SALIF showed increase in Flex-Ext and LB, whereas NZ of TLIF did not increase significantly in any motion direction., Conclusions: Axial compression loading caused loosening of SALIF in Flex-Ext and LB, but not TLIF at L5/S1 in low BMD specimens. Nevertheless, Post-cyclic ROM and NZ of SALIF is comparable to TLIF. This suggests that, neither construct is optimal for the use in patients with reduced BMD., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: Single position lateral fusion with robotic assistance eliminates the need for surgical staging while harnessing the precision of robotic adjuncts. We expand on this technique by demonstrating the technical feasibility of placing bilateral pedicle screws with S2-alar-iliac (S2AI) fixation while in the lateral position., Methods: A cadaveric study was performed using 12 human specimens. A retrospective clinical series was also performed for patients who had undergone robot-assisted placement of S2AI screws in lateral decubitus between June 2020 and June 2022. Case demographics, implant placement time, implant size, screw accuracy, and complications were recorded. Early postoperative radiographic outcomes were reported., Results: In the cadaveric series, a total of 126 screws were placed with robotic assistance in 12 cadavers of which 24 screws were S2AI. There were four breaches from pedicle screws and none with S2AI screws for an overall accuracy rate of 96.8%. In the clinical series, four patients (all male, mean age 65.8 years) underwent single position lateral surgery with S2AI distal fixation. Mean BMI was 33.6 and mean follow-up was 20.5 months. Mean radiographic improvements were lumbar lordosis 12.3 ± 4.7°, sagittal vertical axis 1.5 ± 2.1 cm, pelvic tilt 8.5 ± 10.0°, and pelvic incidence-lumbar lordosis mismatch 12.3 ± 4.7°. A total of 42 screws were placed of which eight screws were S2AI. There were two breaches from pedicle screws and none from S2AI screws for an overall accuracy rate of 95.2%. No repositioning or salvage techniques were required for the S2AI screws., Conclusions: We demonstrate here the technical feasibility of single position robot-assisted placement of S2-alar-iliac screws in the lateral decubitus position for single position surgery., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The pterygomandibular raphe (PMR) is a tendinous bundle between the bucinator (BM) and the superior constrictor of pharynx (SC) and has been considered essential for swallowing. Despite its functional significance, previous studies reported that the PMR is not always present. Another study reported presence of the connecting fascia between the BM and deep temporalis tendon (dTT). Therefore, the present study analyzed the three-dimensional relationship between the BM, SC, and dTT. We examined 13 halves of 11 heads from adult Japanese and Caucasian cadavers: eight halves macroscopically and five halves histologically. There was no clear border between the BM and SC in any specimens macroscopically. The BM attachment varied depending on its levels. At the level of the superior part of the internal oblique line, the BM fused with the SC with no clear border. At the level of the midpart of the internal oblique line of the mandible, the BM attached to the dTT directly, and the SC attached to the dTT via collagen fibers and the BM. Based on these results, these muscles should be described as the BM/dTT/SC (BTS) complex. The three-dimensional relationship of the BTS complex might result in the so-called "pterygomandibular raphe." The BTS complex could be important as a muscle coordination center in chewing and swallowing., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Purpose: The exit points of the supraorbital nerve and its branches hold significant importance in various medical procedures, including supraorbital endoscopic surgeries, forehead-facial aesthetic plastic surgeries, medical aesthetic applications and maxillofacial surgeries. Therefore, the primary objective of the present study was to precisely define the dimension, location and clinical significance of the supraorbital foramen/notch. By doing so, we aimed to enhance our understanding of this anatomical structure and its implications for surgical and aesthetic interventions in the supraorbital region., Methods: For our study, we conducted anatomical dissections and bone measurements to assess the significance of anatomical variations of the supraorbital foramen/notch. We utilized a sample consisting of 28 cadavers and 38 skulls. The supraorbital foramen/notch was bilaterally analyzed in all 28 cadavers and 38 dry bones. We morphometrically analyzed the distance between the supraorbital foramen/notch and various anatomical landmarks, including the nasion, supraorbital margin, infraorbital margin, temporal crest, glabella, frontal cavity and midline of the face. Additionally, we measured the distance between the supraorbital foramen/notches and the frontal foramen/notches, and the width of the supraorbital foramen/notch and the distance between both supraorbital foramina/notches., Results: There are 32 (57.14%) supraorbital  foramina, and the remaining are 24 (42.86%) supraorbital notches in cadavers and there are 36 (47.37%) supraorbital foramina, and the remaining are 40 (52.63%) supraorbital notches in skulls. We observed consistency in the dimension and location values of anatomical measurement parameters between cadavers and dry skulls on both right and left sides, with the exception of the parameter "distance from temporal crest" (p=0.042). Furthermore, our correlation analysis revealed a significant positive relationship between the right and left sides across all parameters, except for the following instances: in dry skulls, "distance from supraorbital margin" and in cadaver parameters, "distance from temporal crest, " "distance from frontal cavity" and "width.", Conclusion: In our study, we observed that the distributions of supraorbital foramina and notches were nearly similar. Furthermore, our findings indicated comparable measurements between the right and left sides in both cadavers and skulls. These results suggest a degree of consistency in supraorbital anatomy within our study sample, regardless of the specimen type (cadavers or skulls) or laterality (right or left side)., No Level Assigned: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. 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., (© 2024. The Author(s).)

Background:  Infraorbital filler injection is a commonly used minimally invasive cosmetic procedure on the face, which can cause vascular complications., Objective:  In this study, we aimed to explore the anatomical structure of the infraorbital vasculature and to establish an accurate protocol for infraorbital filler injection., Methods:  The vascular structure of the infraorbital region was evaluated in 84 hemifacial specimens using computed tomography. Four segments (P1-P4) and five sections (C1-C5) were considered. We recorded the number of identified arteries in each slice and at each location and the number of deep arteries. Furthermore, we also measured the infraorbital artery (IOA) distribution., Results:  At P1-P4, the lowest number of arteries was detected in segment P4, with a 317/1727 (18.4%) and 65/338 (2.3%) probability of total and deep arterial identification, respectively. The probabilities of encountering an identified artery at the five designated locations (C1-C5) were 277/1727 (16%), 318/1727 (18.4%), 410/1727 (23.7%), 397/1727 (23%), and 325/1727 (18.8%), respectively. The probability of an IOA being identified at C2 was 68/84 (81%)., Conclusion:  We described an effective filler injection technique in the infraorbital region to minimize the associated risks., Level of Evidence Iv: 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 ., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Purpose: Mandibular reconstruction remains a challenging procedure despite the availability of various flaps and grafts. The ultimate objective is to restore oral functioning and attain acceptable morphological outcomes while considering donor site morbidity. This study describes the vascular supply and harvesting technique of a pedicled clavicular bone. The proximity of the clavicle is conducive to a mandibular replacement and allows the use of vascularized bone with a single surgical field., Methods: The osteoperiosteal clavicular pedicled flap was harvested on the right side of ten fresh cadaver specimens. The cervical transverse artery was injected with colored latex in some cases and methylene blue in others., Results: The vascular periosteal supply of the clavicular flap was highlighted. The clavicular bone was linked to its pedicle which was composed of vascular and adipose-fascial tissues, without any overlying skin paddle. Its vasculature was supplied by a reverse flow from the ascending cervical artery. The pedicled clavicular bone readily reached the mandible in all dissections., Conclusion: The osteoperiosteal vasculature of the clavicular flap is based on the transverse cervical artery which receives a reverse blood supply from the ascending cervical artery. This vascular pattern is reliable because of the existence of the sub-occipital microvascular network named the "Bosniak node." This pedicled clavicular flap seems to be a robust perspective in both mandibular and facial bone reconstruction. We do not claim that it will replace the existing approaches, but it will expand the surgical panel of mandibular reconstruction. Its clinical realisation will judge its functionality., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: The aim of this study is to investigate the origin and course of the orbital fat arterial supply in the lower eyelid using traditional anatomy and three-dimensional computed tomography (CT)., Methods: Twenty-seven cadaver heads were infused with mercury sulfide contrast media through the ophthalmic artery, maxillary artery, transverse facial artery, and facial artery. CT images were obtained after contrast agent injection, three-dimensional CT scans were reconstructed, and the cadaver heads were dissected., Results: Forty-five qualified hemifaces showed that the orbital fat arterial supply in the lower eyelid originates primarily from the inferomedial muscular trunk (IMT) of the ophthalmic artery and the orbital branch of the infraorbital artery. The medial branch of the IMT terminated at the medial fat pad (35.6%) or the orbital floor (64.4%). The lateral branch terminated at the inferior oblique (IO) muscle (28.9%) or the central and lateral fat pads (17.8%). In 53.3%, the lateral branch extended to the anterior part of the lateral fat pad and terminated in the orbital wall or the zygomaticoorbital foramina. The orbital branch of the infraorbital artery coursed between the orbital floor and the orbital fat, providing supply to the IO muscle, inferior rectus (IR) muscle, nasolacrimal duct, and orbital fat., Conclusion: This study elucidated the origin and course of the orbital fat arterial supply in the lower eyelid, which may help to avoid reducing the blood supply of the orbital fat pedicles during surgery., Level of Evidence Iv: 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 ., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Objectives: This study aims to compare the histological outcomes of three distinct de-epithelialization methods used in (connective tissue grafts) CTG harvested from the palate., Materials and Methods: An experimental study using nine cadaver head specimens was carried out to compare 3 different de-epithelialization techniques for CTG. Eighteen samples were randomly allocated to three study groups: bone scraper, diamond bur and extraoral removal with a scalpel. The main outcome variable was the graft surface percentage without epithelium remains. Additionally, the time employed, and the graft thickness were also measured., Results: Sixteen CTGs were analyzed. The extraoral scalpel group presented a total surface area with no epithelium of 58.84% (22.68) and a mean de-epithelialization time of 3.7 min; the intraoral diamond bur group had 88.24% (41.3) of the surface with no epithelium and took 1.455 min, and the intraoral bone scraper showed 97.98% (5.99) of surface without epithelium and a mean time of 0.815 min (P < 0.05). Histological analysis showed significant differences between the bone scraper and the extraoral group (P = 0.009)., Conclusion: The de-epithelialization technique with a bone scraper seems to be the most effective and fastest de-epithelialization technique for CTG. These findings need to be confirmed in future clinical studies with larger samples., Clinical Relevance: The use of bone scrapers, could be a simple, effective and fast technique to de-epithelialize connective tissue grafts harvested from the palatal area for both novice and experienced surgeons., (© 2024. The Author(s).)

Background: Knowledge of the anatomy of the infraorbital artery (IOA) is crucial for the rejuvenation of the anterior medial aspect of the midface; however, studies adequately describing the anatomy of the IOA branches are lacking, and their connection with the ophthalmic artery branches remains unclear., Objectives: This study aims to elucidate the anatomical characteristics of the IOA in its deployment within the lower eyelid using three-dimensional (3D) technology, thereby offering an anatomical foundation for clinical surgical procedures., Methods: An analysis was conducted on computed tomography scans of 132 cadaveric head sides post-contrast injection, utilizing the Mimics software for reconstruction. The study focused on examining the anastomosis of the IOA, its principal branches, and the branches emanating from the ophthalmic artery., Results: The prevalence of type I IOA was observed at 38.6% (51/132), while Type II IOA was found in 61.4% (81/132) of cases. A 7.6% incidence (10/132) of IOA directly anastomosing with the angular artery was noted. The presence of palpebral branches (PIOA) was identified in 57.6% (76/132) of instances. In the lower eyelid, four distinct distribution patterns of IOA were discerned: The likelihood of Type I PIOA was 5.3%, whereas for Types IIA, IIB, and IIC PIOA, the probabilities were 8.3%, 32.6%, and 11.4%, respectively. The occurrence of the orbital branch of IOA was recorded at 41.7% (55/132)., Conclusions: 3D technology can map IOA variants and identify the deployment patterns of IOA branches in the lower eyelid vascular vesicles at high resolution as a guide in clinical practice., Level of Evidence Iv: 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 ., (© 2024. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Objectives: To evaluate the influence of collateral vascularization on surgical cleft palate closure and deformities., Materials and Methods: Corrosion casting was performed using red-colored acrylic resin in twelve fresh adult cadavers with a normal hard palate. Additionally, white-colored barium sulfate was injected into a fetus with a unilateral complete cleft palate, and layer-by-layer tissue dissection was performed. Both substances were injected into the external carotid arteries. Corrosion casting involved dissolving the soft and hard tissues of the orofacial area utilizing an enzymatic solution., Results: In normal palates, bilateral intraosseous infraorbital arteries formed a network in the premaxilla with the intraosseous nasopalatine- and greater palatine arteries (GPAs). The perforating GPAs anastomosed with the sphenopalatine artery sub-branches. Bilateral extraosseous GPA anastomoses penetrated the median palatine suture. Complex vascularization in the retrotuberal area was detected. In the cleft zone, anastomoses were omitted, whereas in the non-cleft zone, enlarged GPAs were distributed along the cleft edges and followed the anatomical course anteriorly to initiate the network with facial artery sub-branches., Conclusions: The anatomical subunits of the palate exhibited distinct anastomosis patterns. Despite omitted anastomoses with collateral circulation in the cleft zone, arteries maintained their anatomical pattern as seen in the normal specimen in the non-cleft zone., Clinical Relevance: Based on the findings in normal- and cleft palates, surgeons may expect developed anastomosis patterns in the non-cleft zone. Due to the lack of microcirculation in the cleft zone, the existent anastomoses should be maintained as much as possible by the surgical technique. This applies anteriorly in the incisive canal territory, alveolar ridges, and posteriorly in the retrotuberal area., (© 2024. The Author(s).)

Introduction: Division of the suspensory ligament of the penis has emerged as a popular surgical approach for penile lengthening, but accurate preoperative predictions of lengthening outcomes remain elusive. This study aimed to identify readily measurable anatomical parameters associated with post-ligamentolysis penile length gain, facilitating more reliable preoperative estimations., Methods: An experimental cross-sectional study was performed on 16 adult cadavers. Data collected before dissection included: age at death, ethnicity, height, length of the penis before dissection and width of the suspensory ligament of penis. Following the complete dissection of the suspensory ligament of penis, the depth of the pubic symphysis and the penile length after the procedure were measured. The absolute and relative length differences pre- and post-ligamentolysis were calculated. Correlation coefficients were used to study relations between these variables., Results: Penile length increased uniformly after complete division of the suspensory ligament (average gain: 26.38 mm, SD = 14.83 mm; range 4-60 mm). Pearson correlation revealed a significant negative correlation between pre-ligamentolysis penile length and post-ligamentolysis increase (r = - 0.601; p = 0.014), suggesting greater gains in individuals with shorter pre-ligamentolysis lengths. Age, ligament width, and pubic arch depth showed no significant correlations. Ethnicity did not impact post-ligamentolysis length increase (t = - 0.135; p = 0.894)., Conclusions: This study highlights the potential to predict penile length gain post-ligamentolysis through measurable anatomical parameters. The ability to anticipate the outcome of this procedure could empower surgeons to provide informed counseling, potentially elevating patient satisfaction. An experimental cross-sectional study was performed to investigate the outcomes of penile lengthening surgery Penile lengthening was achieved in all subjects via complete dissection of the suspensory ligament of the penis Penile length increase may be predicted preoperatively using easily measurable anatomical parameters NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. 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., (© 2024. The Author(s).)

Background: Botulinum neurotoxin (BoNT) and filler injections into the highly vascularized glabellar region for aesthetical purposes are extremely common. Injections into the glabellar region without precise anatomical knowledge of its vascular and muscular topography may pose the risk of severe complications., Objectives: We aimed to improve the safety and efficacy of the glabellar injections by mapping the regional muscles and vasculature in relation to the medial canthus and the defined reference lines., Methods: Meticulous dissection was performed to reveal glabellar region muscles and arteries under surgical microscope, in 16 hemifaces of whom arteries are injected with red-dyed latex. Location of the angular artery (AA) along with its branches was noted in relation to glabellar muscles., Results: The AA was always located superficial to the levator labii superioris alaeque nasi muscle (LLSAN) and then coursed toward the medial canthus to anastomose with the supratrochlear artery deep to the origin of the depressor supercilii (DS). The AA gave subcutaneously located central and paracentral branches coursing close to the mid-face line in 14 out of 16 hemifaces. Variable muscular connections were also present between the LLSAN, the DS and the procerus (P) muscles. No arteries were detected at the base of the medial eyebrow to which the DS, the P, and the frontalis (F) inserted., Conclusions: This study provides a detailed map of muscular and vascular anatomy of the glabellar region to facilitate safe and efficient filler and BoNT injections without complications., No Level Assigned: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. 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 ., (© 2023. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Surgical approaches directed toward craniovertebral junction (CVJ) can be addressed to the ventral, dorsal, and lateral aspects through a variety of 360° surgical corridors Herein, we report features, advantages, and limits of the updated technical support in CVJ surgery in clinical setting and dissection laboratories enriched by our preliminary surgical results of the simultaneous application of O-arm intraoperative neuronavigation and imaging system along with the 3D-4K EX in TOA for the treatment of CVJ pathologies.In the past 4 years, eight patients harboring CVJ compressive pathologies underwent one-step combined anterior neurosurgical decompression and posterior instrumentation and fusion technique with the aid of exoscope and O-arm. In our equipped Cranio-Vertebral Junction Laboratory, we use fresh cadavers (and injected "head and neck" specimens) whose policy, protocols, and logistics have already been elucidated in previous works. Five fresh-frozen adult specimens were dissected adopting an FLA. In these specimens, a TOA was also performed, as well as a neuronavigation-assisted comparison between transoral and transnasal explorable distances.A complete decompression along with stable instrumentation and fusion of the CVJ was accomplished in all the cases at the maximum follow-up (mean: 25.3 months). In two cases, the O-arm navigation allowed the identification of residual compression that was not clearly visible using the microscope alone. In four cases, it was not possible to navigate C1 lateral masses and C2 isthmi due to the angled projection unfitting with the neuronavigation optical system, so misleading the surgeon and strongly suggesting changing surgical strategy intraoperatively. In another case (case 4), it was possible to navigate and perform both C1 lateral masses and C2 isthmi screwing, but the screw placement was suboptimal at the immediate postoperative radiological assessment. In this case, the hardware displacement occurred 2 months later requiring reoperation., (© 2024. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Purpose: The aim of this study was to assess the efficacy and safety of a novel releasing-closing-tapping approach in the treatment of persistent macular holes (PMHs) after initial surgery with internal limiting membrane (ILM) peeling., Methods: We retrospectively analyzed patients with PMHs after initial surgery with ILM peeling who were treated with a novel releasing-closing-tapping approach. After repeated pars plana vitrectomy (PPV), the surgeon effectively released the adhesion between the edges and retinal pigment epithelium (RPE) by gently scraping the retinal neuroepithelium. Then, the hole was converted into a transverse slit, and the edges were gently tapped flat so that they attached to the RPE, and no space was left under the edges. Finally, air tamponade was carried out. The primary outcome measures included MH closure and the change in best-corrected visual acuity (BCVA) from preoperatively to postoperatively., Results: The study included 11 PMH patients with a mean age of 63.82 ± 3.31 years. The mean minimum linear diameter of PMHs was 666.3 ± 208.1 μm, and the mean basal diameter was 1547.2 ± 351.8 μm. MH closure was achieved in 90.9% (10/11) of eyes, with significant improvement of visual acuity from 1.19 ± 0.30 logMAR to 0.65 ± 0.29 logMAR postoperatively., Conclusion: The releasing-closing-tapping approach with repeated PPV is a simple, effective, and safe surgical procedure for refractory PMHs after initial surgery with ILM peeling that can significantly improve the visual outcome and achieve a high surgical success rate., (© 2023. The Author(s).)

The advent of diffusion tensor imaging (DTI) in addition to cadaveric brain dissection allowed a comprehensive description of an adult human brain. Nonetheless, the knowledge of the development of the internal architecture of the brain is mostly incomplete. Our study aimed to provide a description of the anatomical variations of the major associational bundles, among fetal and early post-natal periods. Seventeen formalin-fixed fetal human brains were enrolled for sulci analysis, and 13 specimens were dissected under the operating microscope, using Klingler's technique. Although fronto-temporal connections could be observed in all stages of development, a distinction between the uncinate fascicle, and the inferior fronto-occipital fascicle was clear starting from the early preterm period (25-35 post-conceptional week). Similarly, we were consistently able to isolate the periatrial white matter that forms the sagittal stratum (SS), with no clear distinction among SS layers. Arcuate fascicle and superior longitudinal fascicle were isolated only at the late stage of development without a reliable description of their entire course. The results of our study demonstrated that, although white matter is mostly unmyelinated among fetal human brains, cadaveric dissection can be performed with consistent results. Furthermore, the stepwise development of the associational fiber tracts strengthens the hypothesis that anatomy and function run in parallel, and higher is the cognitive functions subserved by an anatomical structure, later the development of the fascicle. Further histological-anatomical-DWI investigations are required to appraise and explore this topic., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Knowledge of the anatomy of the deep temporal artery (DTA) is critical to ensure safe filling of the deep temporal region. However, current treatment guidelines still focus on how to avoid the superficial temporal artery and the middle temporal vein, and an understanding of the safety of avoiding DTA injury is lacking., Objective: The purpose of this study was to determine the positioning and course of the DTA to help clinicians safely perform the injection and filling in the temporal region., Methods: Computed tomography (CT) scans and dissections of the skulls of 34 fresh frozen cadavers perfused with lead oxide were performed. Reconstruction and trajectory analysis of all DTA branches were performed using Mimics and MATLAB software., Results: In this study, the DTA was identified in all samples, which originated from the maxillary artery of the external carotid artery system. According to image reconstruction and anatomical observations, the distribution of the anterior and posterior branches of the DTA had two different distribution patterns. The anatomical level of the DTA is located between the temporal muscle and the periosteal layer. Compared with observations in previous studies, the anterior branch of the DTA is slightly different, and we found that its course is closer to the frontal area in Asian specimens., Conclusion: The anatomical information on the DTA described in this study may help improve awareness of the safety of temporal injection by aesthetic physicians., Level of Evidence Iv: 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 Table of Contents or online Instructions to Authors www.springer.com/00266. ., (© 2023. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Purpose: To develop and test synthetic vertebral stabilization techniques ("vertebropexy") that can be used after decompression surgery and furthermore to compare them with a standard dorsal fusion procedure., Methods: Twelve spinal segments (Th12/L1: 4, L2/3: 4, L4/5: 4) were tested in a stepwise surgical decompression and stabilization study. Stabilization was achieved with a FiberTape cerclage, which was pulled through the spinous process (interspinous technique) or through one spinous process and around both laminae (spinolaminar technique). The specimens were tested (1) in the native state, after (2) unilateral laminotomy, (3) interspinous vertebropexy and (4) spinolaminar vertebropexy. The segments were loaded in flexion-extension (FE), lateral shear (LS), lateral bending (LB), anterior shear (AS) and axial rotation (AR)., Results: Interspinous fixation significantly reduced ROM in FE by 66% (p = 0.003), in LB by 7% (p = 0.006) and in AR by 9% (p = 0.02). Shear movements (LS and AS) were also reduced, although not significantly: in LS reduction by 24% (p = 0.07), in AS reduction by 3% (p = 0.21). Spinolaminar fixation significantly reduced ROM in FE by 68% (p = 0.003), in LS by 28% (p = 0.01), in LB by 10% (p = 0.003) and AR by 8% (p = 0.003). AS was also reduced, although not significantly: reduction by 18% (p = 0.06). Overall, the techniques were largely comparable. The spinolaminar technique differed from interspinous fixation only in that it had a greater effect on shear motion., Conclusion: Synthetic vertebropexy is able to reduce lumbar segmental motion, especially in flexion-extension. The spinolaminar technique affects shear forces to a greater extent than the interspinous technique., (© 2023. The Author(s).)

Objectives: To investigate the intraosseous arterial pathways and anastomoses in the alveolar aspects of the maxilla in order to better understand the arterial scattering pattern., Materials and Methods: Eleven cadavers were selected for macroscopic intraosseous arterial analyses by corrosion casting. The red-colored acrylic resin was injected into the external carotid arteries. The specimens were kept in an enzymatic solution at 36 °C for about 60 days, depending on the process progression. After removal of the soft tissues and drying, the bone was macerated by potassium hydroxide to analyze the course and the mean diameters of the intraosseous anastomoses., Results: Vertico-oblique and horizontal intraosseous arteries and anastomoses between the greater palatine-, posterior superior alveolar-, and infraorbital arteries were detected. The vertico-oblique anastomoses were found on the anterolateral wall of the maxilla and the alveolar crest with a mean diameter of 0.46 mm; nevertheless, the horizontal (transalveolar) anastomoses were identified in the interdental septum/alveolar crest with the mean diameter of 0.41 mm. From the horizontal anastomoses, small intraseptal branches supplied the territory of the alveolar socket in various directions., Conclusions: The localization of intraosseous arterial anastomoses is critical in implant-related surgeries, predominantly to maintain proper circulation., Clinical Relevance: Based on vertico-oblique and transalveolar anastomoses, simultaneous buccal- and palatal flap elevation (particularly on the palatal side) should be avoided to minimize patient morbidity and intra- or postoperative complications. Moreover, preserving transverse loops in the interdental septum is essential during implant surgeries, which can significantly influence collateral periosteal and osteal circulation to prevent ischemia., (© 2023. The Author(s).)

Purpose: Articles evaluating radiofrequency (RF) safety are insufficient. Thus, the purpose of this study was to investigate RF safety during biportal endoscopic lumbar decompressive laminotomy by measuring epidural temperature after RF use., Methods: Both in vitro cadaveric study and in vivo study were performed. The epidural temperature was measured at epidural space after RF use in three cadavers. The epidural temperature was measured and analysed according to RF mode, RF power, RF usage time, and saline irrigation patency. In the in vivo study, the epidural temperature was measured after biportal endoscopic surgery. Epidural temperatures were measured around ipsilateral and contralateral traversing nerve roots after 1-s use of RF., Results: In the in vivo study, epidural space temperature was increased by 0.31 ± 0.16 °C ipsilaterally and 0.29 ± 0.09° contralaterally after RF use in coagulation mode 1. The epidural temperature of epidural space was increased by 0.21 ± 0.13 °C ipsilaterally and 0.15 ± 0.21 °C contralaterally after RF use in high mode 2. In the in vitro study, epidural temperature was significantly increased with a long duration of RF use and a poor patency of irrigation fluid., Conclusion: The use of RF in biportal endoscopic spine surgery might be safe. In order to reduce indirect thermal injuries caused by RF use, it might be necessary to reduce RF use time and maintain continuous saline irrigation patency well., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: The aim of this study was to elucidate segmental range of motion (ROM) before and after common decompression and fusion procedures on the lumbar spine., Methods: ROM of fourteen fresh-frozen human cadaver lumbar segments (L1/2: 4, L3/4: 5, L5/S1: 5) was evaluated in six loading directions: flexion/extension (FE), lateral bending (LB), lateral shear (LS), anterior shear (AS), axial rotation (AR), and axial compression/distraction (AC). ROM was tested with and without posterior instrumentation under the following conditions: 1) native 2) after unilateral laminotomy, 3) after midline decompression, and 4) after nucleotomy., Results: Median native ROM was FE 6.8°, LB 5.6°, and AR 1.7°, AS 1.8 mm, LS 1.4 mm, AC 0.3 mm. Unilateral laminotomy significantly increased ROM by 6% (FE), 3% (LB), 12% (AR), 11% (AS), and 8% (LS). Midline decompression significantly increased these numbers to 15%, 5%, 21%, 20%, and 19%, respectively. Nucleotomy further increased ROM in all directions, most substantially in AC of 153%. Pedicle screw fixation led to ROM decreases of 82% in FE, 72% in LB, 42% in AR, 31% in AS, and 17% in LS. In instrumented segments, decompression only irrelevantly affected ROM., Conclusions: The amount of posterior decompression significantly impacts ROM of the lumbar spine. The here performed biomechanical study allows creation of a simplified rule of thumb: Increases in segmental ROM of approximately 10%, 20%, and 50% can be expected after unilateral laminotomy, midline decompression, and nucleotomy, respectively. Instrumentation decreases ROM by approximately 80% in bending moments and accompanied decompression procedures only minorly destabilize the instrumentation construct., (© 2023. The Author(s).)

Purpose: To develop ligamentous vertebral stabilization techniques ("vertebropexy") that can be used after microsurgical decompression (intact posterior structures) and midline decompression (removed posterior structures) and to elaborate their biomechanical characteristics., Methods: Fifteen spinal segments were biomechanically tested in a stepwise surgical decompression and ligamentous stabilization study. Stabilization was achieved with a gracilis or semitendinosus tendon allograft, which was attached to the spinous process (interspinous vertebropexy) or the laminae (interlaminar vertebropexy) in form of a loop. The specimens were tested (1) in the native state, after (2) microsurgical decompression, (3) interspinous vertebropexy, (4) midline decompression, and (5) interlaminar vertebropexy. In the intact state and after every surgical step, the segments were loaded in flexion-extension (FE), lateral shear (LS), lateral bending (LB), anterior shear (AS) and axial rotation (AR)., Results: Interspinous vertebropexy significantly reduced the range of motion (ROM) in all loading scenarios compared to microsurgical decompression: in FE by 70% (p < 0.001), in LS by 22% (p < 0.001), in LB by 8% (p < 0.001) in AS by 12% (p < 0.01) and in AR by 9% (p < 0.001). Interlaminar vertebropexy decreased ROM compared to midline decompression by 70% (p < 0.001) in FE, 18% (p < 0.001) in LS, 11% (p < 0.01) in LB, 7% (p < 0.01) in AS, and 4% (p < 0.01) in AR. Vertebral segment ROM was significantly smaller with the interspinous vertebropexy compared to the interlaminar vertebropexy for all loading scenarios except FE. Both techniques were able to reduce vertebral body segment ROM in FE, LS and LB beyond the native state., Conclusion: Vertebropexy is a new concept of semi-rigid spinal stabilization based on ligamentous reinforcement of the spinal segment. It is able to reduce motion, especially in flexion-extension. Studies are needed to evaluate its clinical application., (© 2023. The Author(s).)

Purpose: To evaluate the motion-preserving properties of vertebral body tethering with varying cord/screw constructs and cord thicknesses in cadaveric thoracolumbar spines., Methods: In vitro flexibility tests were performed on six fresh-frozen human cadaveric spines (T1-L5) (2 M, 4F) with a median age of 63 (59-to-80). An ± 8 Nm load was applied to determine range of motion (ROM) in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) in the thoracic and lumbar spine. Specimens were tested with screws (T5-L4) and without cords. Single (4.0 mm and 5.0 mm) and double (4.0 mm) cord constructs were sequentially tensioned to 100 N and tested: (1) Single 4.0 mm and (2) 5.0 mm cords (T5-T12); (3) Double 4.0 mm cords (T5-12); (4) Single 4.0 mm and (5) 5.0 mm cord (T12-L4); (6) Double 4.0 mm cords (T12-L4)., Results: In the thoracic spine (T5-T12), 4.0-5.0 mm single-cord constructs showed slight reductions in FE and 27-33% reductions in LB compared to intact, while double-cord constructs showed reductions of 24% and 40%, respectively. In the lumbar spine (T12-L4), double-cord constructs had greater reductions in FE (24%), LB (74%), and AR (25%) compared to intact, while single-cord constructs exhibited reductions of 2-4%, 68-69%, and 19-20%, respectively., Conclusions: The present biomechanical study found similar motion for 4.0-5.0 mm single-cord constructs and the least motion for double-cord constructs in the thoracic and lumbar spine suggesting that larger diameter 5.0 mm cords may be a more promising motion-preserving option, due to their increased durability compared to smaller cords. Future clinical studies are necessary to determine the impact of these findings on patient outcomes., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To compare the residual range of motion (ROM) of cortical screw (CS) versus pedicle screw (PS) instrumented lumbar segments and the additional effect of transforaminal interbody fusion (TLIF) and cross-link (CL) augmentation., Methods: ROM of thirty-five human cadaver lumbar segments in flexion/extension (FE), lateral bending (LB), lateral shear (LS), anterior shear (AS), axial rotation (AR), and axial compression (AC) was recorded. After instrumenting the segments with PS (n = 17) and CS (n = 18), ROM in relation to the uninstrumented segments was evaluated without and with CL augmentation before and after decompression and TLIF., Results: CS and PS instrumentations both significantly reduced ROM in all loading directions, except AC. In undecompressed segments, a significantly lower relative (and absolute) reduction of motion in LB was found with CS 61% (absolute 3.3°) as compared to PS 71% (4.0°; p = 0.048). FE, AR, AS, LS, and AC values were similar between CS and PS instrumented segments without interbody fusion. After decompression and TLIF insertion, no difference between CS and PS was found in LB and neither in any other loading direction. CL augmentation did not diminish differences in LB between CS and PS in the undecompressed state but led to an additional small AR reduction of 11% (0.15°) in CS and 7% (0.05°) in PS instrumentation., Conclusion: Similar residual motion is found with CS and PS instrumentation, except of slightly, but significantly inferior reduction of ROM in LB with CS. Differences between CS and PS in diminish with TLIF but not with CL augmentation., (© 2023. The Author(s).)

Background: Lumbar spinal stenosis is a common disease in the aging population. Decompression surgery represents the treatment standard, however, a risk of segmental destabilization depending on the approach and extent of decompression is discussed. So far, biomechanical studies on techniques were mainly conducted on non-degenerated specimens. This biomechanical in vitro study aimed to investigate the increase in segmental range of motion (ROM) depending on the extent of decompression in degenerated segments., Methods: Ten fresh frozen lumbar specimens were embedded in polymethyl methacrylate (PMMA) and loaded in a spine tester with pure moments of ± 7.5 Nm. The specimens were tested in their intact state for lateral bending (LB), flexion/extension (FE) and axial rotation (AR). Subsequently, four different decompression techniques were performed: unilateral interlaminar decompression (DC1), unilateral with "over the top" decompression (DC2), bilateral interlaminar decompression (DC3) and laminectomy (DC4). The ROM of the index segment was reported as percent (%) of the native state., Results: Specimens were measured in their intact state prior to decompression. The mean ROM was defined as 100% (FE:6.3 ± 2.3°; LB:5.4 ± 2.8°; AR:3.0 ± 1.6°). Interventions showed a continuous ROM increase: FE (DC1: + 4% ± 4.3; DC2: + 4% ± 4.5; DC3: + 8% ± 8.3;DC4: + 20% ± 15.9), LB(DC1: + 4% ± 6.0; DC2: + 5% ± 7.3; DC3: + 8% ± 8.3; DC4: + 11% ± 9.9), AR (DC1: + 7% ± 6.0; DC2: + 9% ± 7.9; DC3: + 15% ± 11.5; DC4: + 19% ± 10.5). Significant increases in ROM for all motion directions (p < 0.05) were only obtained after complete laminectomy (DC4)., Conclusion: Unilateral and/or bilateral decompressive surgery resulted in a statistically insignificant ROM increase, whereas complete laminectomy showed statistically significant ROM increase. If this ROM increase also has an impact on the clinical outcome and how to identify segments at risk for secondary lumbar instability should be evaluated in further studies., (© 2023. The Author(s).)

Purpose: Odontoidectomy for ventral compressive pathology may result in O-C1 and/or C1-2 instability. Same-stage endonasal C1-2 spinal fusion has been advocated to eliminate risks associated with separate-stage posterior approaches. While endonasal methods for C1 instrumentation and C1-2 trans-articular stabilization exist, no hypothetical construct for endonasal occipital instrumentation has been validated. We provide an anatomic description of anterior occipital condyle (AOC) screw endonasal placement as proof-of-concept for endonasal craniocervical stabilization., Methods: Eight adult, injected cadaveric heads were studied for placing 16 AOC screws endonasally. Thin-cut CT was used for registration. After turning a standard inferior U-shaped nasopharyngeal flap endonasally, 4 mm × 22 mm AOC screws were placed with a 0° driver using neuronavigation. Post-placement CT scans were obtained to determine: site-of-entry, measured from the endonasal projection of the medial O-C1 joint; screw angulation in sagittal and axial planes, proximity to critical structures., Results: Average site-of-entry was 6.88 mm lateral and 9.74 mm rostral to the medial O-C1 joint. Average angulation in the sagittal plane was 0.16° inferior to the palatal line. Average angulation in the axial plane was 23.97° lateral to midline. Average minimum screw distances from the jugular bulb and hypoglossal canal were 4.80 mm and 1.55 mm., Conclusion: Endonasal placement of AOC screws is feasible using a 0° driver. Our measurements provide useful parameters to guide optimal placement. Given proximity of hypoglossal canal and jugular bulb, neuronavigation is recommended. Biomechanical studies will ultimately be necessary to evaluate the strength of AOC screws with plate-screw constructs utilizing endonasal C1 lateral mass or C1-2 trans-articular screws as inferior fixation points., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

BACKGROUND Anatomical dissections play an irreplaceable role in the training of new generations of effective neurosurgeons, especially when addressing skull base lesions is required.The Authors describe an inter-laboratory dissection study aimed at improving the knowledge of a complex region of the skull base. The anterior and middle incisural spaces are of remarkable anatomical and surgical interest due to complex relationships between bony, dural, arachnoidal, and neurovascular structures. The primary purposes of this study are to describe the anatomy of this region with particular emphasis on the relationships between the anterior margin of the free edge of the tentorium and the sphenoid and petrous bone; to identify surgical implications in many different types of neurosurgical procedures dealing with this challenging complex anatomic area.METHODS Thirteen anatomical specimens, including five injected specimens, were dissected in this study. In the formalin-fixed specimens, vessels were injected with colored silicone.RESULTS The anatomical study focused on the description of the relationships between bony dural, arachnoid, and neurovascular structures. Surgical implications are described accordingly.CONCLUSIONS Detailed anatomical knowledge of this region finds concrete applications in neurosurgical practice since the anterior and middle incisural spaces are often surgically exposed in neoplastic and vascular diseases. The high-definition pictures reported in this study could represent useful support to understand the anatomy of this complex region.Finally, our study could provide guidance to neurosurgical centers in which resources are limited that are either planning to establish their own cadaver dissection laboratory or failed to do so because of the supposed high-costs., (© 2023. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

The angular gyrus (AG) wraps the posterior end of the superior temporal sulcus (STS), so it is considered a continuation of the superior temporal gyrus (STG)/ middle temporal gyrus (MTG) and forms the inferior parietal lobule (IPL) with the supramarginal gyrus (SMG). The AG was functionally divided in the literature, but there is no fiber dissection study in this context. This study divided AG into superior (sAG) and inferior (iAG) parts by focusing on STS. Red, blue silicone-injected eight and four non-silicone-injected human cadaveric cerebrums were dissected via the Klingler method focusing on the AG. White matter (WM) tracts identified during dissection were then reconstructed on the Human Connectome Project 1065 individual template for validation. According to this study, superior longitudinal fasciculus (SLF) II and middle longitudinal fasciculus (MdLF) are associated with sAG; the anterior commissure (AC), optic radiation (OR) with iAG; the arcuate fasciculus (AF), inferior frontooccipital fasciculus (IFOF), and tapetum (Tp) with both parts. In cortical parcellation of AG based on STS, sAG and iAG were associated with different fiber tracts. Although it has been shown in previous studies that there are functionally different subunits with AG parcellation, here, for the first time, other functions of the subunits have been revealed with cadaveric dissection and tractography images., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose The role of cadaver labs in preparing new generations of effective neurosurgeons is of paramount importance. The Authors describe a personal cadaver lab experience aimed at improving the knowledge of a difficult region of the central skull base. The anterior and middle incisural spaces are regions of remarkable anatomical, and surgical interest due to complex relationships between bony, dural, arachnoidal, and neurovascular structures. The primary purpose of this study is (1) to describe the anatomy of this region with particular emphasis on the relationships between the anterior margin of the free edge of the tentorium and the sphenoid and petrous bone; (2) to identify surgical implications in many different types of neurosurgical procedures dealing with this challenging complex anatomic area.Methods Eight fresh, non-formalin-fixed non-silicon-injected adult cadaver heads and five injected formalin-fixed adult cadaver heads were analyzed in this study.Results The anatomical study was focused on the description of the relationships between bony, dural, arachnoid, and neurovascular structures. Surgical implications are described accordingly.Conclusions Detailed anatomical knowledge of this region finds concrete applications in neurosurgical practice since the anterior and middle incisural spaces are often surgically exposed in neoplastic and vascular diseases., (© 2023. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

BACKGROUND Anatomical dissections play an irreplaceable role in the training of new generations of effective neurosurgeons, especially when addressing skull base lesions is required.The Authors describe an inter-laboratory dissection study aimed at improving the knowledge of a complex region of the skull base. The anterior and middle incisural spaces are of remarkable anatomical and surgical interest due to complex relationships between bony, dural, arachnoidal, and neurovascular structures. The primary purposes of this study are to describe the anatomy of this region with particular emphasis on the relationships between the anterior margin of the free edge of the tentorium and the sphenoid and petrous bone; to identify surgical implications in many different types of neurosurgical procedures dealing with this challenging, complex anatomic area.METHODS Thirteen anatomical specimens, including five injected specimens, were dissected in this study. In the formalin-fixed specimens, vessels were injected with colored silicone.RESULTS The anatomical study was focused on the description of the relationships between bony dural, arachnoid, and neurovascular structures. Surgical implications are described accordingly.CONCLUSIONS Detailed anatomical knowledge of this region finds concrete applications in neurosurgical practice since the anterior and middle incisural spaces are often surgically exposed in neoplastic and vascular diseases. The high-definition pictures reported in this study could represent useful support to understand the anatomy of this complex region.Finally, our study could provide guidance to neurosurgical centers in which resources are limited that are either planning to establish their own cadaver dissection laboratory or failed to do so because of the supposed high-costs., (© 2023. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Objective: Although the supraorbital (SO) keyhole approach has a wide range of indications, its routine usefulness with the advance of current technology has not been fully evaluated. In an attempt to address this issue, a cadaveric morphometric analysis to the supra- and parasellar regions was performed, comparing the standard Pterional craniotomy (PT) with the SO keyhole., Methods: ETOH-fixed and silicone-injected human cadaveric heads were used. SO (n = 8) and PT craniotomies (n = 8) were performed. Pre- and post-dissection CT, along with pre-dissection MRI scans were also completed for neuro-navigation purposes, aimed to verify predetermined anatomical landmarks selected for morphometric analysis., Results: Notwithstanding the smaller craniotomy, the SO approach allowed optimal anatomical exposure when compared to the PT approach. With 30° of head rotation, the SO keyhole showed a wider surgical field of the suprasellar region., Conclusions: Using detailed preoperative image-guided surgical planning, the SO keyhole approach offered an appropriate alternative route to the supra- and parasellar regions, compared to the PT craniotomy., (© 2023. The Author(s), under exclusive license to Springer Nature Switzerland AG.)

Background: Both autologous and cadaveric grafts are often used during rhinoplasty to create volume and provide support. Despite discussion in the literature comparing the efficacy, cost-effectiveness, and complication rates between grafting options, it remains unclear which is the superior choice when considering availability, donor site morbidity, and cost. There is a little description of the current use of these materials amongst facial plastic surgeons., Methods: A 12 question survey was created, and IRB approval was obtained. The survey was distributed to practicing members of the AAFPRS via their membership listserv., Results: 178 respondents completed the survey for an overall response rate of 17.5%. The most common rhinoplasty graft types used by respondents were autologous septal cartilage (96.6%), autologous auricular grafts (93.8%), autologous rib graft (ARG) (75.8%), and cadaveric rib graft (CRG) (56.7%). Patient comorbidities and performing more than 50 rhinoplasties per year were positively correlated with use of CRG grafts and concerns about complications and cost were negatively correlated., Conclusions: While autologous septal and auricular cartilage remain the most common graft choices amongst surveyed facial plastic surgeons, a majority utilize cadaveric rib grafts in their practice. Patient comorbidities, surgery volume, concerns about graft complications, and cost were the chief factors associated with use of cadaveric grafts amongst survey respondents., 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 ., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Purpose: Significant risk of injury to the lumbar plexus and its departing motor and sensory nerves exists with lateral lumbar interbody fusion (LLIF). Several cadaveric and imaging studies have investigated the lumbar plexus position with respect to the vertebral body anteroposterior plane. To date, no systematic review and meta-analysis of the lumbar plexus safe working zones for LLIF has been performed., Methods: This systematic review was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Relevant studies reporting on the position of the lumbar plexus with relation to the vertebral body in the anteroposterior plane were identified from a PubMed database query. Quantitative analysis was performed using Welch's t test., Results: Eighteen studies were included, encompassing 1005 subjects and 2472 intervertebral levels. Eleven studies used supine magnetic resonance imaging (MRI) with in vivo subjects. Seven studies used cadavers, five of which performed dissection in the left lateral decubitus position. A significant correlation (p < 0.001) existed between anterior lumbar plexus displacement and evaluation with in vivo MRI at all levels between L1-L5 compared with cadaveric measurement. Supine position was also associated with significant (p < 0.001) anterior shift of the lumbar plexus at all levels between L1-L5., Conclusions: This is the first comprehensive systematic review and meta-analysis of the lumbar neural components and safe working zones for LLIF. Our analysis suggests that the lumbar plexus is significantly displaced ventrally with the supine compared to lateral decubitus position, and that MRI may overestimate ventral encroachment of lumbar plexus., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: The superior labial artery (SLA) is a facial artery (FA) that drains into the peri-oral region (dangerous area of face). Owing to the recent rise in the demand for reconstructive procedures and filler injections in this region, it is important to understand its arterial topography. This paper aims to study the embranchment pattern of the labial arteries in the eastern Indian population., Method: An observational study using conventional dissection and dry dye injection methods was conducted to visualize the facial and superior labial arteries in 56 hemifaces. The origin, morphometry (length and diameter), branching pattern, and termination of the arteries were recorded and compared with the existing data., Results: Two hemifaces were excluded from analysis (vessels damaged in dissection); in the remaining 54, a single SLA was present in all samples originating at a mean distance of 1.29 ± 0.32 cm from oral commissure (68.51% originating above). Lee type II (independent SLA giving off alar branch) was the predominant pattern (56.2%), followed by type I (independent SLA and alar branches, 33%) and type III (FA terminating as SLA, 10.8%). The average length of SLA was 4.75 ± 1.28 cm and 4.56 ± 0.78 cm on the right and left sides, respectively., Conclusion: The SLA is highly variable in occurrence, course, and depth, sometimes even occurring unilaterally; therefore, any intervention in this region should be done with caution. Since the SLA was not found subcutaneously at the vermillion border, the intradermal and the subcutaneous injections used here are relatively safer., Level of Evidence Iv: 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 ., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Purpose: Most surgeons perform right-sided semicircular clearance of the superior mesenteric artery (SMA) nerve plexus for pancreatic head carcinoma, presuming a linear course of the SMA nerve fibers. The hypothesis was that the SMA nerve plexus fibers follow a non-linear course, and the goal of the present study was to assess the neural fibers distribution along the SMA., Methods: The course of neural fibers along the retropancreatic and suprapancreatic SMA was assessed in 7 cadavers., Results: In the retropancreatic course of the vessel, the main nerve cords branch and form a large number of finer nerve branches performing an anti-clockwise rotation of slightly less than 90° around the SMA. Finer nerve branches are located rather close to the vessel, while the main nerve cords are localized in the loose connective tissue of the peripheral parts of the vascular sheath. Nerve fibers around the suprapancreatic SMA run as two main nerve cords framing the artery on the right lateral-ventral and the left lateral to lateral-dorsal side., Conclusion: The rotation of the nerve fiber around the SMA indicates that a more radical resection of at least 180° of neural tissue around the SMA might be required to achieve tumor clearance in pancreatic cancer with perineural invasion at the uncinate margin., (© 2022. The Author(s).)

Purpose: While anteroposterior instability of spinal segments is regarded as an important biomechanical aspect in the clinical evaluation of lumbar pathologies, the reliability of the available diagnostic tools is limited and an intraoperative method to quantify stability is lacking. The aim of this study was to develop and validate an instrument to measure the anteroposterior stability of a spinal segments in real-time., Methods: Torsi of five fresh-frozen human cadavers were used for this study. After pedicle screw insertion, a specifically modified reposition tool composed with load and linear sensors was used to measure the segmental anteroposterior motion caused by 100 N anterior and posterior force during 5 loading cycles on either side of the instrumentation by two different operators. The spinal segments were then resected from the torsi and anteroposterior loading with ± 100 N was repeated in an advanced biomechanical spine testing setup as a reference measurement. The Inter-correlation coefficient (ICC) was used for validation of the "intraoperative" device., Results: Inter-operator repeatability of the measurements showed an ICC of 0.93 (p < 0.0001) and the bilateral (left-right) comparison had an ICC of 0.73 (p < 0.0001). The ICC resulting from the comparison to the reference measurement was 0.82 (p < 0.0001) without offset correction, and 0.9 (p < 0.0001) with offset correction. The ICC converged at this value already after two of the five performed loading cycles., Conclusion: An accurate and reliable measurement tool is developed and validated for real-time quantification of anteroposterior stability of spinal segments and serves as a basis for future intraoperative use., (© 2022. The Author(s).)

Background: An ovoid, slender face with a smooth contour is preferred in oriental esthetics. We developed a novel concept to achieve a slimmer and harmonious midface contour by liposuction of the projection area of the zygomatic arch., Methods: A cadaver study including anatomical dissection and histologic examination were conducted to better understand the soft tissue structure of the projection area of the zygomatic arch and the vital technique for liposuction. For the clinical evaluation, 49 patients with midface hypertrophy who underwent liposuction of the zygomatic arch area from January 2016 to June 2021 were retrospectively reviewed., Results: Cadaver study showed that abundant fatty tissue existed in the subcutaneous layer of the zygomatic arch area. The liposuction manipulation was precisely limited to the subcutaneous fat layer, and nerve branches were observed in the deeper loose areolar tissue plane. Of the 49 patients enrolled in this study (including 98 zygomatic arch areas), the median fat removal volume per zygomatic arch area was 3.0 (2.0, 5.0) mL. The subcutaneous fat thickness was significantly decreased postoperatively [median 9 (6, 10) mm vs. 1 (1, 2) mm per zygomatic arch area, P &lt; 0.001]. All patients were satisfied with their postoperative outcomes. Only three patients underwent slight depression of the liposuction area during making facial expression after surgery and subsequently recovered., Conclusions: Liposuction of the zygomatic arch area is effective in improving midface hypertrophy and achieving a harmonious facial contour with a low risk of complications., Level of Evidence Iv: 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 ., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

Background: Temporal hollowing is an early sign of aging, and many techniques comprising the injection of fillers into the temporal fossa to correct this hollowing have been described., Objective: To assess the safety of a new technique in which stromal vascular fraction gel is used for temporal hollowing., Methods: Thirty-three patients with temporal hollowing were corrected with the aforementioned gel using deep injection and shallow pave filling at the Department of Plastic and Reconstructive Surgery, Guangdong Women and Children Hospital, China, between January 2017 and April 2021. This gel was injected into the double plane via a needle and cannula by the same cutaneous access points to prevent severe vascular injury. Improvement was evaluated by self-assessment, the Hollowness Severity Rating Scale (grade range, 0-3; lower grades represent minimal hollowness), and a satisfaction survey., Results: Self-assessment questionnaire (6 questions) results were satisfactory; 44 temples (67%) demonstrated more than 2 grades of magnitude of clinical improvement. Thirty-one patients (94%) were satisfied with their outcomes; the complaint ratio was low., Conclusion: The high satisfaction rate of patients treated using the stromal vascular fraction gel by deep injection and shallow pave filling suggests that this technique is simple, effective, and safe., Level of Evidence Iv: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. 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 ., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

The skin, as the largest organ, covers the entire outer part of the body, and since this organ is directly exposed to microbial, thermal, mechanical and chemical damage, it may be destroyed by factors such as acute trauma, chronic wounds or even surgical interventions. Cell therapy is one of the most important procedures to treat skin lesions. Fibroblasts are cells that are responsible for the synthesis of collagen, elastin, and the organization of extracellular matrix (ECM) components and have many vital functions in wound healing processes. Today, cultured autologous fibroblasts are used to treat wrinkles, scars, wounds and subcutaneous atrophy. The results of many studies have shown that fibroblasts can be effective and beneficial in the treatment of skin lesions. On the other hand, skin substitutes are used as a regenerative model to improve and regenerate the skin. The use of these alternatives, restorative medicine and therapeutic cells such as fibroblasts has tremendous potential in the treatment of skin diseases and can be a new window for the treatment of diseases with no definitive treatment. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description ofthese Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 ., (© 2022. Springer Science+Business Media, LLC, part of Springer Nature and International Society of Aesthetic Plastic Surgery.)

The temporo-parietal junction (TPJ) is a cortical area contributing to a multiplicity of visual, language-related, and cognitive functions. In line with this functional richness, also the organization of the underlying white matter is highly complex and includes several bundles. The few studies tackling the outcome and neurological burdens of surgical operations addressing TPJ document the presence of language disturbances and visual field damages, with the latter hardly recovered in time. This observation advocates for identifying and functionally monitoring the optic radiation (OR) bundles that cross the white matter below the TPJ. In the present study, we adopted a multimodal approach to address the anatomo-functional correlates of the OR's dorsal loop. In particular, we combined cadavers' dissection with tractographic and electrophysiological data collected in drug-resistant epileptic patients explored by stereoelectroencephalography (SEEG). Cadaver dissection allowed us to appreciate the course and topography of the dorsal loop. More surprisingly, both tractographic and electrophysiological observations converged on a unitary picture highly coherent with the data obtained by neuroanatomical observation. The combination of diverse and multimodal observations allows overcoming the limitations intrinsic to single methodologies, defining a unitary picture which makes it possible to investigate the dorsal loop both presurgically and at the individual patient level, ultimately contributing to limit the postsurgical damages. Notwithstanding, such a combined approach could serve as a model of investigation for future neuroanatomical inquiries tackling white matter fibers anatomy and function through SEEG-derived neurophysiological data., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The numbness of the nasal tip is the main symptom of the external nasal nerve injury, especially after rhinoplasty. This postoperative syndrome can reduce the patient's satisfaction with the operation. Having a better understanding of the anatomical structure and intraoperative protection can effectively avoid nerve injury. At present, the anatomical research on this nerve is all from Asia. This study aims to fill the gap in the anatomical study of this nerve in Caucasians and provides comparative results with Asians., Material and Methods: A total of 20 Caucasian cadavers were embalmed using the Thiel method. On dissection, after complete exposure of the external nasal nerves, the distance between the exit point of the external nasal nerve and the nasal midline was measured, and the morphology of the nerves was compared with the Asian data. The nerves were classified into types based on their branching pattern., Results: The nerve plane was the same as the Asian record. The distance ranged from 5.08 to 11.94 mm (mean, 8.31 ± 1.85 mm). This distance has statistical significant difference compared with the Asian population (P < 0.01). The average distance is larger, and the distribution range of the exit point is wider. On classification, 35 of 40 cases had the same type results as those previously reported, with the primary types I, II and III. Five new varieties were found which are classified as subtypes of the primary types and a new type IV. Furthermore, the bifurcation position in two-thirds of the type II cases and variations is proximal to that seen in the Asian population., Conclusions: The anatomical structure of the external nasal nerve in Caucasians and Asians has obvious differences. This nerve in Caucasians is more likely to be damaged during rhinoplasty than Asians. Except the primary types, the classification of the external nasal nerve also includes subtypes and type IV., Level of Evidence Iii: 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 ., (© 2021. The Author(s).)

Pseudoaneurysms of the lumbar arteries following transforaminal lumbar interbody fusion (TLIF) are rare postoperative complications that usually occur around the transverse process. However, there are few detailed descriptions of the transverse branch and other branches of the dorsal branches at the L1-L4 disks., Study Design: Ten adult embalmed cadavers were anatomically studied., Objectives: The purposes of the study were to describe the vascular distribution of the dorsal branches, especially the transverse branches, at the L1-L4 levels and provide information useful for TLIF., Methods: Ten embalmed cadavers studied after their arterial systems were injected with red latex. The quantity, origin, pathway, distribution range and diameter of the branches were recorded and photographed., Results: The transverse branch appeared in all 80 intervertebral foramina. The transverse branch was divided into 2 types: In type 1, the arteries divided into superior branches and inferior branches; the arteries in type 2 divided into 3 branches (superior, intermedius and inferior branches)., Conclusions: The transverse branches of the dorsal arteries are common structures from L1 to L4, and 2 types of transverse branches were found. A thorough understanding of the dorsal branches, especially the transverse branches of the lumbar artery, may be very important for reducing both intraoperative bleeding during the surgery and the occurrence of pseudoaneurysms after transforaminal lumbar interbody fusion., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Surgical treatment of thoracolumbar A3-fractures usually comprises posterior fixation-in neutral position or distraction-potentially followed by subsequent anterior support. We hypothesized that additional posterior compression in circumferential stabilization may increase stability by locking the facets, and better restore the sagittal profile., Methods: Burst fractures Type A3 were created in six fresh frozen cadaver spine segments (T12-L2). Testing was performed in a custom-made spinal loading simulator. Loads were applied as pure bending moments of ± 3.75 Nm in all six movement axes. We checked range of motion, neutral zone and Cobb's angle over the injured/treated segment within the following conditions: Intact, fractured, instrumented in neutral alignment, instrumented in distraction, with cage left in posterior distraction, with cage with posterior compression., Results: We found that both types of instrumentation with cage stabilized the segment compared to the fractured state in all motion planes. For flexion/extension and lateral bending, flexibility was decreased even compared to the intact state, however, not in axial rotation, being the most critical movement axis. Additional posterior compression in the presence of a cage significantly decreased flexibility in axial rotation, thus achieving stability comparable to the intact state even in this movement axis. In addition, posterior compression with cage significantly increased lordosis compared to the distracted state., Conclusion: Among different surgical modifications tested, circumferential fixation with final posterior compression as the last step resulted in superior stability and improved sagittal alignment. Thus, posterior compression as the last step is recommended in these pathologies., (© 2021. The Author(s).)