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OBJECTIVE The study objective was to create a novel milestones evaluation form for neurosurgery sub-interns and assess its potential as a quantitative and standardized performance assessment to compare potential residency applicants. In this pilot study, the authors aimed to determine the form’s interrater reliability, relationship to percentile assignments in the neurosurgery standardized letter of recommendation (SLOR), ability to quantitatively differentiate tiers of students, and ease of use. METHODS Medical student milestones were either adapted from the resident Neurological Surgery Milestones or created de novo to evaluate a student’s medical knowledge, procedural aptitude, professionalism, interpersonal and communication skills, and evidence-based practice and improvement. Four milestone levels were defined, corresponding to estimated 3rd-year medical student through 2nd-year resident levels. Faculty and resident evaluations as well as student self-evaluations were completed for 35 sub-interns across 8 programs. A cumulative milestone score (CMS) was computed for each student. Student CMSs were compared both within and between programs. Interrater reliability was determined with Kendall’s coefficient of concordance (Kendall’s W). Student CMSs were compared against their percentile assignments in the SLOR using analysis of variance with post hoc testing. CMS-derived percentile rankings were assigned to quantitatively distinguish tiers of students. Students and faculty were surveyed on the form’s usefulness. RESULTS The average faculty rating overall was 3.20, similar to the estimated competency level of an intern. Student and faculty ratings were similar, whereas resident ratings were lower (p < 0.001). Students were rated most highly in coachability and feedback (3.49 and 3.67, respectively) and lowest in bedside procedural aptitude (2.90 and 2.85, respectively) in both faculty and self-evaluations. The median CMS was 26.5 (IQR 21.75–29.75, range 14–32) with only 2 students (5.7%) achieving the highest rating of 32. Programs that evaluated the most students differentiated the highest-performing students from the lowest by at least 13 points. A program with 3 faculty raters demonstrated scoring agreement across 5 students (p = 0.024). The CMS differed significantly between SLOR percentile assignments, despite 25% of students being assigned to the top fifth percentile. CMS-driven percentile assignment significantly differentiated the bottom, middle, and top third of students (p < 0.001). Faculty and students strongly endorsed the milestones form. CONCLUSIONS The medical student milestones form was well received and differentiated neurosurgery sub-interns both within and across programs. This form has potential as a replacement for numerical Step 1 scoring as a standardized, quantitative performance assessment for neurosurgery residency applicants.

Spinal epidural lipomatosis is a rare condition commonly associated with chronic corticosteroid use and obesity that involves deposition of adipose tissue in the epidural space of the spinal canal. This accumulation of adipose tissue may cause compression of the spinal cord and/or nerve roots and result in compressive symptoms such as myelopathy or radiculopathy. Spinal involvement is usually confined to either the thoracic or lumbar spine but can infrequently affect both regions. Depending on pre-existing conditions, treatment options include weight loss and discontinuation of exogenous steroid use, both of which have been shown to be effective therapeutic methods. Surgical decompression may be useful for appropriately selected patients in whom conservative therapy has failed or who experience acute neurological deterioration, although this is rarely indicated.In this study, we describe a patient receiving long-term corticosteroid therapy who presented with symptomatic epidural lipomatosis that involved the thoracic and lumbar spine. She was treated with decompression by continuous T3-L5 hemilaminectomies performed through 5 small incisions of alternating laterality. After surgery, the patient experienced clinical improvement and was able to return to her baseline.We illustrate a successful spinal decompression of extensive epidural lipomatosis through a less-invasive surgical approach using several small incisions to accomplish uninterrupted hemilaminectomies. This alternative approach to a standard continuous incision can be considered in cases of extensive spinal epidural lipomatosis in patients with multiple medical comorbidities in whom wound healing is believed to be an issue and for whom minimizing blood loss is crucial.

During lateral lumbar fusion, the trajectory of implant insertion approaches the great vessels anteriorly and the segmental arteries posteriorly, which carries the risk of vascular complications. We aimed to analyze vascular injuries for potential differences between oblique lateral interbody fusion (OLIF) and lateral lumbar interbody fusion (LLIF) procedures at our institution. This was coupled with a systematic literature review of vascular complications associated with lateral lumbar fusions. A retrospective chart review was completed to identify consecutive patients who underwent lateral access fusions. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used for the systematic review with the search terms "vascular injury" and "lateral lumbar surgery." Of 260 procedures performed at our institution, 211 (81.2%) patients underwent an LLIF and 49 (18.8%) underwent an OLIF. There were no major vascular complications in either group in this comparative study, but there were four (1.5%) minor vascular injuries (2 LLIF, 0.95%; 2 OLIF, 4.1%). Patients who experienced vascular injury experienced a greater amount of blood loss than those who did not (227.5 ± 147.28 vs. 59.32 ± 68.30 ml) (p = 0.11). In our systematic review of 63 articles, major vascular injury occurred in 0-15.4% and minor vascular injury occurred in 0-6% of lateral lumbar fusions. The systematic review and comparative study demonstrate an increased rate of vascular injury in OLIF when compared to LLIF. However, vascular injuries in either procedure are rare, and this study aids previous literature to support the safety of both approaches.

Background Postoperative pain after complex revision spine surgery, especially for the treatment of persistent spinal pain syndrome (PSPS), is frequently severe and can be debilitating, requiring the use of intravenous and oral opioids. To the best of our knowledge, the present study is the first to evaluate the effectiveness and safety of a continuous infusion regional anesthesia pump placed after thoracopelvic fusion for the treatment of PSPS. Methods We performed a retrospective comparative study of consecutive patients who had undergone thoracopelvic fusion for PSPS. The patients included in the present study had either had a continuous infusion regional anesthesia pump placed during surgery or had not (control). Demographics, use of preoperative and postoperative opioids, postoperative adverse events, length of hospital stay, and 90-day readmission were recorded. Results The patients in the pump group (n = 14) had used fewer opioids during their hospital stay compared with the control group (n = 12; P = 0.6). This difference was greater for postoperative days 1 and 2 (P = 0.3 and P = 0.2, respectively). No significant difference was found in opioid usage during the first 14 days after surgery (P = 0.8) or at the 3-month postoperative follow-up evaluation (P = 0.8). Furthermore, no significant difference was found between the 2 groups in terms of postoperative complications. The pump group had a 1.4-day shorter hospital stay (P = 0.7). The control group had more 90-day readmissions than did the pump group (P = 0.2). Conclusions Despite showing a trend toward less usage of opioids during the first 2 days after surgery and a shorter hospital stay with no increased complications in the pump group, the study data failed to demonstrate a statistically significant difference between the two groups.

BACKGROUND: Current literature on robot-assisted S2 alar-iliac (S2AI) screw placement shows favorable outcomes and screw accuracy; however, the data is limited by a few retrospective, single-surgeon studies. To the author’s knowledge, this is the first multicenter study which evaluates the accuracy of robot-assisted S2AI screws. METHODS: Adult (≥18 years old) patients who underwent robot-assisted S2AI screw placement from 2017–2019 were reviewed. All surgeries used the same proprietary robotic guidance system, Mazor X (Mazor Robotics Ltd). RESULTS: A total of 65 screws were assessed in 31 patients. The mean follow-up ± standard deviation was 362±190 days (minimum was 90 days). The mean age was 61.1±11 years old, and 54.8% (n=17) of patients were female. Nearly half of the patients had a primary diagnosis of degenerative scoliosis (48.4%, n=15). Other diagnosis included pseudarthrosis (22.6%, n=7), degenerative disc disease (16.1%, n=5), and high-grade spondylolisthesis (12.9%, n=4). The mean length and diameter of screws were 84.6±6.1 mm and 8.4±0.7, respectively. The mean axial and sagittal angles were 50.0±6.3 and 24.0±10.5, respectively. The overall screw accuracy was 93.8% (n=61). There were four iliac cortex breaches (anterior =3, inferior 1) with a mean breach distance of 3.5±3.2. No statistically significant differences in screw length, diameter, axial angle, and sagittal angle were observed between screws with and without a breach. No intraoperative neurologic, vascular, or visceral complications from the S2AI screw were observed. No post-discharge wound complications, screw prominence issues, or revision of S2AI screws were observed during the study’s follow-up period. CONCLUSIONS: Robot-assisted S2AI screw placement was found to be safe and accurate in this multicenter study. This is largely attributed to the versatility of the robotic guidance software that allows for detailed and precise preoperative and intraoperative planning.

Robot-assisted spine surgery continues to rapidly develop as evidenced by the growing literature in recent years. In addition to demonstrating excellent pedicle screw accuracy, early studies have explored the impact of robot-assisted spine surgery on reducing radiation time, length of hospital stay, operative time, and perioperative complications in comparison to conventional freehand technique. Recently, the Mazor X Stealth Edition was introduced in 2018. This robotic system integrates Medtronic's Stealth navigation technology into the Mazor X platform, which was introduced in 2016. It is unclear what the impact of these advancements have made on clinical outcomes.To compare the outcomes and complications between the most recent iterations of the Mazor Robot systems: Mazor X and Mazor X Stealth Edition.Multicenter cohort PATIENT SAMPLE: Among four different institutions, we included adult (≥18 years old) patients who underwent robot-assisted spine surgery with either the Mazor X (non-navigated robot) or Stealth (navigated robot) platforms.Primary outcomes included robot time per screw, fluoroscopic radiation time, screw accuracy, robot abandonment, and clinical outcomes with a minimum 90 day follow up.A one-to-one propensity-score matching algorithm based on perioperative factors (e.g. demographics, comorbidities, primary diagnosis, open vs. percutaneous instrumentation, prior spine surgery, instrumented levels, pelvic fixation, interbody fusion, number of planned robot screws) was employed to control for the potential selection bias between the two robotic systems. Chi-square/fisher exact test and t-test/ANOVA were used for categorical and continuous variables, respectively.From a total of 646 patients, a total of 372 adult patients were included in this study (X: 186, Stealth: 186) after propensity score matching. The mean number of instrumented levels was 4.3. The mean number of planned robot screws was 7.8. Similar total operative time and robot time per screw occurred between cohorts (p0.05). However, Stealth achieved significantly shorter fluoroscopic radiation time per screw (Stealth: 7.2 seconds vs. X: 10.4 seconds, p.001) than X. The screw accuracy for both robots was excellent (Stealth: 99.6% vs. X: 99.1%, p=0.120). In addition, Stealth achieved a significantly lower robot abandonment rate (Stealth: 0% vs. X: 2.2%, p=0.044). Furthermore, a lower blood transfusion rate was observed for Stealth than X (Stealth: 4.3% vs. X: 10.8%, p=0.018). Non-robot related complications such as dura tear, motor/sensory deficits, return to the operating room during same admission, and length of stay was similar between robots (p0.05). The 90-day complication rates were low and similar between robot cohorts (Stealth: 5.4% vs. X: 3.8%, p=0.456).In this multicenter study, both robot systems achieved excellent screw accuracy and low robot time per screw. However, using Stealth led to significantly less fluoroscopic radiation time, lower robot abandonment rates, and reduced blood transfusion rates than Mazor X. Other factors including length of stay, and 90-day complications were similar.

To report our experience using the scan-and-plan workflow and review current literature on surgical efficiency, safety, and accuracy of next-generation robot-assisted (RA) spine surgery.The records of patients who underwent RA pedicle screw fixation were reviewed. The accuracy of pedicle screw placement was determined based on the Ravi classification system. To evaluate workflow efficiency, 3 demographically matched cohorts were created to analyze differences in time per screw placement (defined as operating room [OR] time divided by number of screws placed). Group A had4 screws placed, Group B had 4 screws placed, and Group C had4 screws placed. Intraoperative errors and postoperative complications were collected to elucidate safety.Eighty-four RA cases (306 pedicle screws) were included for analysis. The mean number of screws placed was 2.1 ± 0.3 in Group A and 6.4 ± 1.2 in Group C; 4 screws were placed in Group B patients. The accuracy rate (Ravi grade I) was 98.4%. Screw placement time was significantly longer in Group A (101 ± 37.7 minutes) than Group B (50.5 ± 25.4 minutes) or C (43.6 ± 14.7 minutes). There were no intraoperative complications, robot failures, or in-hospital complications requiring a return to the OR.The scan-and-plan workflow allowed for a high degree of accuracy. It was a safe method that provided a smooth and efficient OR workflow without registration errors or robotic failures. After the placement of 4 pedicle screws, the per-screw time remained constant. Further studies regarding efficiency and utility in multilevel procedures are necessary.

Study design Multicenter cohort. Objective To compare the robot time/screw, radiation exposure, robot abandonment, screw accuracy, and 90-day outcomes between robot-assisted percutaneous and robot-assisted open approach for short lumbar fusion (1-and 2-level). Summary of background data There is conflicting literature on the superiority of robot-assisted minimally invasive spine surgery to open techniques. A large, multicenter study is needed to further elucidate the outcomes and complications between these two approaches. Methods We included adult patients (≥18 years old) who underwent robot-assisted short lumbar fusion surgery from 2015-2019 at four independent institutions. A propensity score matching (PSM) algorithm was employed to control for the potential selection bias between percutaneous and open surgery. The minimum follow-up was 90 days after the index surgery. Results After PSM, 310 patients remained. The mean (standard deviation) charlson comorbidity index was 1.6 (1.5) and 53% of patients were female. The most common diagnoses included high grade spondylolisthesis (grade >2)(48%), degenerative disc disease (22%), and spinal stenosis (25%), and the mean number of instrumented levels was 1.5(0.5). The operative time was longer in the open (198 minutes) vs. the percutaneous group (167 minutes, P-value=0.007). However, the robot time/screw was similar between cohorts (P-value>0.05). The fluoroscopy time/screw for percutaneous (14.4 seconds) was longer than the open group (10.1 seconds, P-value=0.021). The rates for screw exchange and robot abandonment, were similar between groups (P-value>0.05). The estimated blood loss (open:146 mL vs. percutaneous:61.3 mL, P-value 0.05). Conclusion Percutaneous robot-assisted spine surgery may increase radiation exposure, but can achieve a shorter operative time and lower risk for intraoperative blood loss for short-lumbar fusion. Percutaneous approaches do not appear to have an advantage for other short-term postoperative outcomes. Future multicenter studies on longer fusion surgeries and the inclusion of patient-reported outcomes are needed.Level of Evidence: 3.

Background Lumbar spine fusion surgery is traditionally performed with rigid fixation. Because the rigidity is often supraphysiologic, semirigid rods were developed. To the best of our knowledge, a comprehensive evaluation of rod material type on surgical outcomes has yet to be conducted. Methods A systematic review based on PRISMA guidelines was conducted across 3 electronic databases. After examination for inclusion and exclusion criteria, data were extracted from the studies. Results Seventeen studies, including 1399 patients, were included in this review. The mean rigid rod fusion rate is 92.2% and 95.5% for semirigid rods (P = 0.129). The mean improvement in back pain was 60.6% in rigid rods and 71.6% in semirigid rods. The improvement in leg pain was 81.9% and 77.2%, respectively. There were no differences in visual analog scale back pain score (P = 0.098), visual analog scale leg pain score (P = 0.136), or in functional improvement between rigid and semirigid rods (P = 0.143). There was no difference (P = 0.209) in the reoperation rate between rigid rods (13.1%) and semirigid rods (6.5%). There was a comparable incidence of adjacent segment disease (3%), screw fracture (1.7%), and wound infection (1.9%) between rod material types. Conclusions There is a moderate level of evidence supporting that surgical intervention results in high fusion rates regardless of rod material type. Surgical intervention improves back pain, leg pain, and function, with neither material type showing clear superiority. There are comparable rates of reoperation, development of adjacent segment disease, development of mechanical complications, and incidence of infection in both rigid and semirigid rods. Further studies regarding rod material type are warranted.

Persistent opioid utilization after spine surgery is a rising complication among both preoperatively opioid-naïve and opioid-tolerant patients. To our knowledge, this is the first meta-analysis to determine the prevalence and characterize the risk factors that predispose patients to prolonged opioid use (≥3 months) after lumbar fusion.Studies were identified through searches in PubMed and EMBASE from each database's earliest records to February 1, 2022. We included observational studies examining the risk factors and rates of prolonged opioid use following lumbar fusion. Pooled odds ratios (ORs) or standardized mean differences with corresponding 95% confidence intervals (CI) were estimated using inverse-variance methods.In this meta-analysis of 12 studies encompassing 80,935 patients, 40.2% of patients continued to fill opioid prescriptions ≥3 months after lumbar fusion. Significant sociodemographic predictors included Medicare or Medicaid insurance (OR=1.60, 95% CI 1.36-1.88), African-American ethnicity (OR=1.29, 95% CI 1.18-1.41), being from the Southern United States (OR=1.18, 95% CI 1.11-1.25), or women (OR=1.10, 95% CI 1.01-1.20). Being from the Midwestern United States (OR=0.80, 95% CI 0.75-0.85) was found to be a protective factor. Comorbidities associated with increased risk of prolonged opioid use were preoperative opioid use (OR=5.76, 95% CI 3.52-9.41), drug abuse (OR=3.11, 95% CI 2.37-4.08), alcohol abuse (OR=2.37, 95% CI 2.14-2.64), psychiatric disorders (OR=2.29, 95% CI 1.94-2.70), smoking history (OR=1.81, 95% CI 1.23-2.66), arthritis (OR=1.35, 95% CI 1.29-1.40), and higher American Society of Anesthesiologists score (standardized mean difference=0.72, 95% CI 0.61-0.82).The high prevalence of prolonged opioid use after lumbar fusion underscores the importance of screening patients for comorbidities and implementing targeted strategies to minimize opioid misuse.

To determine risk factors increasing susceptibility to early complications (intraoperative and postoperative within 6 weeks) associated with surgery to correct thoracic and lumbar spinal deformity.We systematically searched the PubMed and EMBASE databases for studies published between January 1990 and September 2021. Observational studies evaluating predictors of early complications of thoracic and lumbar spinal deformity surgery were included. Pooled odds ratio (OR) or standardized mean difference (SMD) with 95% confidence intervals (CI) was calculated via the random effects model.Fifty-two studies representing 102,432 patients met the inclusion criteria. Statistically significant patient-related risk factors for early complications included neurological comorbidity (OR = 3.45, 95% CI 1.83-6.50), non-ambulatory status (OR = 3.37, 95% CI 1.96-5.77), kidney disease (OR = 2.80, 95% CI 1.80-4.36), American Society of Anesthesiologists score 2 (OR = 2.23, 95% CI 1.76-2.84), previous spine surgery (OR = 1.98, 95% CI 1.41-2.77), pulmonary comorbidity (OR = 1.94, 95% CI 1.21-3.09), osteoporosis (OR = 1.60, 95% CI 1.17-2.20), cardiovascular diseases (OR = 1.46, 95% CI 1.20-1.78), hypertension (OR = 1.37, 95% CI 1.23-1.52), diabetes mellitus (OR = 1.84, 95% CI 1.30-2.60), preoperative Cobb angle (SMD = 0.43, 95% CI 0.29, 0.57), number of comorbidities (SMD = 0.41, 95% CI 0.12, 0.70), and preoperative lumbar lordotic angle (SMD = - 0.20, 95% CI - 0.35, - 0.06). Statistically significant procedure-related factors were fusion extending to the sacrum or pelvis (OR = 2.53, 95% CI 1.53-4.16), use of osteotomy (OR = 1.60, 95% CI 1.12-2.29), longer operation duration (SMD = 0.72, 95% CI 0.05, 1.40), estimated blood loss (SMD = 0.46, 95% CI 0.07, 0.85), and number of levels fused (SMD = 0.37, 95% CI 0.03, 0.70).These data may contribute to development of a systematic approach aimed at improving quality-of-life and reducing complications in high-risk patients.

Butterfly glioblastoma (bGBM) is a grade 4 glioma with a poor prognosis. Surgical treatment of these cancers has been reviewed in the literature with some recent studies supporting resection as a safe and effective treatment instead of biopsy and adjuvant therapy. This meta-analysis was designed to determine whether there are significant differences in overall survival (OS) and postoperative neurologic deficits (motor, speech, and cranial nerve) following intervention in patients who underwent tumor resection as part of their treatment, compared to patients who underwent biopsy without surgical resection. A literature search was conducted using PubMed (National Library of Medicine) and Embase (Elsevier) to identify articles from each database's earliest records to May 25, 2021, that directly compared the outcomes of biopsy and resection in bGBM patients and met predetermined inclusion criteria. A meta-analysis was conducted to compare the effects of the two management strategies on OS and postoperative neurologic deficits. Six articles met our study inclusion criteria. OS was found to be significantly longer for the resection group at 6 months (odds ratio [OR] 2.94, 95% confidence interval [CI] 1.23-7.05) and 12 months (OR 3.75, 95% CI 1.10-12.76) than for the biopsy group. No statistically significant differences were found in OS at 18 and 24 months. Resection was associated with an increased rate of postoperative neurologic deficit (OR 2.05, 95% CI 1.02-4.09). Resection offers greater OS up to 1 year postintervention than biopsy alone; however, this comes at the cost of higher rates of postoperative neurologic deficits.

With growing emphasis on high-value care, many institutions have been working on improving surgical efficiency, quality, and complication reduction. Unfortunately, data are limited regarding perioperative factors that may influence length of stay (LOS) following transforaminal lumbar interbody fusion (TLIF). We sought to design a predictive algorithm that determined patients at risk of prolonged LOS after TLIF. The goal was to identify patients who would benefit from preoperative intervention aimed to reduce LOS.We conducted a review of perioperative data for patients who underwent TLIF between 2014 and 2019. Univariate and multivariate stepwise regression models were used to analyze risk factor effects on postoperative LOS.Two hundred and sixty-nine patients were identified (57.2% women). Mean age at surgery was 61.7 ± 12.3 years. Mean postoperative LOS was 3.08 ± 1.54 days. In multivariate analysis, American Society of Anesthesiologists class (odds ratio [OR] = 1.441, 95% confidence interval [CI] 1.321-1.571), preoperative functional status (OR = 1.237, 95% CI 1.122-1.364), Oswestry Disability Index (OR = 1.010, 95% CI 1.004-1.016), and estimated blood loss (OR = 1.050, 95% CI 1.003-1.101) were independent risk factors for postoperative LOS ≥ 5 days. The final model had an area under the curve of 0.948 with good discrimination and was implemented in the form of an online calculator ( https://spine.shinyapps.io/TLIF_LOS/ ).The prediction tool derived can be useful for assessing likelihood of prolonged LOS in patients undergoing TLIF. With external validation, this calculator may ultimately assist healthcare providers in identifying patients at risk for prolonged hospitalization so preoperative interventions can be undertaken to reduce LOS, thus reducing resource utilization.

Cage subsidence following transforaminal lumbar interbody fusion (TLIF) has been associated with poor bone quality. Current evidence suggests that the magnetic resonance imaging (MRI)-based vertebral bone quality (VBQ) score correlates with poor bone quality.To our knowledge, this is the first study to assess whether the VBQ score can predict the occurrence of postoperative cage subsidence after TLIF surgery.Retrospective single-center cohort.Patients undergoing single-level TLIF for degenerative spine disease between February 2014 and October 2021.Extent of subsidence.Demographic, procedure-related, and radiographic data were collected for study patients. VBQ scores were determined from preoperative T1-weighted MRI. Subsidence was defined as ≥2 mm of migration of the cage into the superior or inferior end plate or both. Univariate and multivariate logistic regression were used to determine the correlation between potential risk factors for subsidence and actual subsidence rates.Subsidence was observed among 42 of the 74 study patients. The mean VBQ scores were 2.9±0.5 for patients with subsidence and 2.5±0.5 for patients without subsidence. The difference among groups was significant (p=.003). On multivariate logistic regression, a higher VBQ score was significantly associated with an increased risk of subsidence (OR=1.5, 95% CI=1.160-1.973, p=.004) and was the only significant independent predictor of subsidence after TLIF.We found that a higher VBQ score was significantly associated with cage subsidence following TLIF. The MRI-VBQ score may be a valuable tool for assisting in identifying patients at risk of cage subsidence following TLIF.

The prone transpsoas approach is a relatively new technique to correct segmental kyphosis and global sagittal imbalance in a minimally invasive fashion. Here, we provide a detailed case report using the prone transpsoas approach to address adjacent segment disease and flatback deformity. This technique allows considerable restoration of segmental lordosis with lateral interbody placement and posterior decompression and fusion using a single position approach. Our experience with the surgical technique and the advantages and challenges unique to this approach are discussed.

Spine surgery is continuously evolving. The synergy between medical imaging and advances in computation has allowed for stereotactic neuronavigation and its integration with robotic technology to assist in spine surgery. The discovery of x-rays in 1895, the development of image intensifiers in 1940, and then advancements in computational science and integration have allowed for the development of computed tomography. In combination with the advancements of stereotaxy in the late 1980s, and manipulation of volumetric and special data for 3-dimensional reconstruction in 1998, computed tomography has revolutionized neuronavigational systems. Integrating all these technologies, robotics in spine surgery was introduced in 2004. Since then, it has become a safe modality that can reproducibly place accurate pedicle screws. Robotics may have the added benefits of improving the surgical workflow and optimizing surgeon ergonomics. Growing at a rapid rate, the second-generation spinal robotics have overcome preliminary limitations and errors. However, comparatively, robotics in spine surgery remains in its infancy. By leveraging technologic advancements in medical imaging, computation, and stereotactic navigation, robotics in spine surgery will continue to mature and expand in utility.

Study DesignCadaver study.ObjectivesAssess the feasibility of robot-assisted cervical pedicle screw (RA-CPS) placement and understand the anatomical considerations of this technique.MethodsFour cadaver specimens free from bony pathology were acquired. Anatomical considerations, such as pedicle width (PW) and height (PH), transverse pedicle angle (TPA), and maximal screw length (MSL), were recorded from preoperative computational tomography (CT) scans. Intraoperative cone-beam CT was acquired and registered to the robotic system. After cervical levels were segmented, screw sizes and trajectories were planned, and RA-CPS were placed. Accuracy was assessed using Gertzbein and Robbin’s classification on postoperative CT scans.ResultsThirty-five RA-CPS were placed. Major breaches (≥Grade C) occurred in 28.57% screws. Grade A or B accuracy was found in 71.43% of screws, with the most common direction of breach being medial (81.3%). The greatest proportion of breach per level occurred in the upper subaxial levels, (C3:71.4%, C4 66.6%, C5:50%) which had the smallest PW (C3: 4.34 ± .96 mm, C4: 4.48 ± .60, C5: 5.76 ± 1.11). PH was greatest at C2 (8.14 ± 1.89 mm) and ranged subaxial from 6.36 mm (C3) to 7.48 mm (C7). The mean PW was 5.37 mm and increased caudally from 4.34 mm (C3) to 6.31 mm (C7). The mean TPA was 39.9° and decreased moving caudally 46.9°) to C7 (34.4°). The MSL was 37.1 mm and increased from C2 (26.3 mm) to C7 (41.0 mm).ConclusionRA-CPS has the potential to be feasible, but technological and instrument modifications are necessary to increase the accuracy in the cervical region.

Lateral lumbar interbody fusion has inherent limitations, such as the necessity to reposition the patient. To overcome this limitation, the prone transpsoas (PTP) approach for lateral lumbar interbody fusion has been developed.To report clinical and radiographic outcome measures of a series of patients who underwent PTP at our hospital.A retrospective chart review was conducted to identify patients who underwent PTP for degenerative lumbar spine disease between September 2019 and August 2021. A thorough analysis of clinical and radiographic outcome measures for these patients was conducted.Our search resulted in the identification of 15 consecutive patients. Four patients were operated using the assistance of fluoroscopy-based instrument tracking. Overall, the mean follow-up duration was 11.9 ± 7.9 months. Radiographically, the PTP approach resulted in significant postoperative improvement of lumbar lordosis ( P = .03) and pelvic incidence minus lumbar lordosis ( Plt; .005). No significant difference was found postoperatively in other regional sagittal alignment parameters, including pelvic tilt, sacral slope, or pelvic incidence. Clinically, the patients' Oswestry Disability Indices ( P = .002) and Short Form Survey-12 Physical Scores improved significantly ( P = .01). The estimated mean blood loss for patients who underwent the PTP procedure was 137.7 ± 96.4 mL, the mean operative time was 212.5 ± 77.1 minutes, and the mean hospital stay was 2.7 ± 1.4 days. One patient each had superficial wound infection, transient paralytic ileus, transient pulmonary embolism, transient urinary retention, or required revision lumbar surgery.This study demonstrates that the PTP approach is associated with significant improvement in radiographic and clinical outcomes.

Lateral mass screw (LMS) fixation for the treatment of subaxial cervical spine instability or deformity has been traditionally associated with few neurovascular complications. However, cervical pedicle screw (CPS) fixation has recently increased in popularity, especially with navigation assistance, because of the higher pullout strength of the pedicle screws. To their knowledge, the authors conducted the first meta-analysis comparing the complication rates during and/or after CPS and LMS placement for different pathologies causing cervical spine instability. A systematic literature search of PubMed and Embase from inception to January 12, 2021 was performed to identify studies reporting CPS and/or LMS-related complications. Complications were categorized into intraoperative and early postoperative (within 30 days of surgery) and late postoperative (after 30 days from surgery) complications. All studies that met the prespecified inclusion criteria were pooled and cumulatively analyzed. A total of 24 studies were conducted during the time frame of the search and comprising 1768 participants and 8636 subaxially placed screws met the inclusion criteria. The CPS group experienced significantly more postoperative C5 palsy (odds ratio [OR] = 3.48, 95% confidence interval [CI] = 1.27-9.53, p 0.05). Otherwise, there were no significant differences between the LMS and CPS groups. There were no significant differences between the CPS and LMS groups in terms of neurovascular procedure-related complications other than significantly more C5 palsy in the CPS group.

During lateral lumbar fusion, the trajectory of implant insertion approaches the great vessels anteriorly and the segmental arteries posteriorly, which carries the risk of vascular complications. We aimed to analyze vascular injuries for potential differences between oblique lateral interbody fusion (OLIF) and lateral lumbar interbody fusion (LLIF) procedures at our institution. This was coupled with a systematic literature review of vascular complications associated with lateral lumbar fusions. A retrospective chart review was completed to identify consecutive patients who underwent lateral access fusions. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used for the systematic review with the search terms "vascular injury" and "lateral lumbar surgery." Of 260 procedures performed at our institution, 211 (81.2%) patients underwent an LLIF and 49 (18.8%) underwent an OLIF. There were no major vascular complications in either group in this comparative study, but there were four (1.5%) minor vascular injuries (2 LLIF, 0.95%; 2 OLIF, 4.1%). Patients who experienced vascular injury experienced a greater amount of blood loss than those who did not (227.5 ± 147.28 vs. 59.32 ± 68.30 ml) (p = 0.11). In our systematic review of 63 articles, major vascular injury occurred in 0-15.4% and minor vascular injury occurred in 0-6% of lateral lumbar fusions. The systematic review and comparative study demonstrate an increased rate of vascular injury in OLIF when compared to LLIF. However, vascular injuries in either procedure are rare, and this study aids previous literature to support the safety of both approaches.

Here we present a novel application of cortical bone trajectory (CBT) fixation utilizing robotic guidance in a previously instrumented spine with a traditional pedicle screw (PS), obviating the need for a larger posterior incision, reducing the risk of infection, muscular dissection, and likely decreasing hospital length of stay. A 60-year-old woman with prior left L3-L4 extreme lateral interbody fusion and unilateral percutaneous PS placed at L3 to L5 presented with progressive bilateral lower-extremity pain and diminished sensation in the S1 dermatome secondary to adjacent segment disease (ASD). The patient underwent an L5-S1 anterior lumbar interbody fusion for indirect decompression and restoration of segmental lordosis. After the first stage was completed, she was turned prone for posterior percutaneous instrumentation. Given prior instrumentation at L3-L5 on the left side, a robot planning software was used to plan a cortical bone screw on the left L5 pedicle. A left S1 PS was then planned with the screw head aligning with the left L5 cortical bone screw. Instrumentation was then placed percutaneously using the robot bilaterally without issue. Intraoperative fluoroscopic imaging demonstrated accurate placement of PS, and postoperative computed tomography demonstrated the excellent positioning of all PSs. This report is the first documented case of a robotically placed CBT screw placed in the same pedicle as a prior traditional PS for ASD. This method expands the surgical options for ASD to include robotic percutaneous placement of posterior instrumentation at the same level as previous instrumentation.

OBJECTIVERecent literature describing complications associated with spinopelvic fixation with iliac screws in adult patients has been limited but has suggested high complication rates. The authors’ objective was to report their experience with iliac screw fixation in a large series of patients with a 2-year minimum follow-up.METHODSOf 327 adult patients undergoing spinopelvic fixation with iliac screws at the authors’ institution between 2010 and 2015, 260 met the study inclusion criteria (age ≥ 18 years, first-time iliac screw placement, and 2-year minimum follow-up). Patients with active spinal infection were excluded. All iliac screws were placed via a posterior midline approach using fluoroscopic guidance. Iliac screw heads were deeply recessed into the posterior superior iliac spine. Clinical and radiographic data were obtained and analyzed.RESULTSTwenty patients (7.7%) had iliac screw–related complication, which included fracture (12, 4.6%) and/or screw loosening (9, 3.5%). No patients had iliac screw head prominence that required revision surgery or resulted in pain, wound dehiscence, or poor cosmesis. Eleven patients (4.2%) had rod or connector fracture below S1. Overall, 23 patients (8.8%) had L5–S1 pseudarthrosis. Four patients (1.5%) had fracture of the S1 screw. Seven patients (2.7%) had wound dehiscence (unrelated to the iliac screw head) or infection. The rate of reoperation (excluding proximal junctional kyphosis) was 17.7%. On univariate analysis, an iliac screw–related complication rate was significantly associated with revision fusion (70.0% vs 41.2%, p = 0.013), a greater number of instrumented vertebrae (mean 12.6 vs 10.3, p = 0.014), and greater postoperative pelvic tilt (mean 27.7° vs 23.2°, p = 0.04). Lumbosacral junction–related complications were associated with a greater mean number of instrumented vertebrae (12.6 vs 10.3, p = 0.014). Reoperation was associated with a younger mean age at surgery (61.8 vs 65.8 years, p = 0.014), a greater mean number of instrumented vertebrae (12.2 vs 10.2, p = 0.001), and longer clinical and radiological mean follow-up duration (55.8 vs 44.5 months, p < 0.001; 55.8 vs 44.6 months, p < 0.001, respectively). On multivariate analysis, reoperation was associated with longer clinical follow-up (p < 0.001).CONCLUSIONSPrevious studies on iliac screw fixation have reported very high rates of complications and reoperation (as high as 53.6%). In this large, single-center series of adult patients, iliac screws were an effective method of spinopelvic fixation that had high rates of lumbosacral fusion and far lower complication rates than previously reported. Collectively, these findings argue that iliac screw fixation should remain a favored technique for spinopelvic fixation.

Objective To study the differences between robot-guided (Mazor X, Mazor Robotics Ltd., Caesarea, Israel) and 3-dimensional (3D) computed tomography (CT) navigation (O-arm Surgical Imaging System, Medtronic, Minneapolis, Minnesota, USA) for the insertion of pedicle screws. Methods We reviewed the charts of 50 patients who underwent robot-guided pedicle screw insertion (between May 2017–October 2017), and 49 patients who underwent 3D-CT navigation pedicle screw insertion (between September 2015–August 2016). Variables included were age, sex, body mass index, blood loss, length of stay, lumbar level(s), operation time, fluoroscopy time, radiation dose, accuracy, and time-per-screw placement. Results Mean ages were 59.3 years in the robotic group and 58.2 years in the 3D-CT navigation group. Mean was 30.7 kg/m2 in the robotic group and 32.1 kg/m2 in the 3D-CT navigation group. Mean time-per-screw placement was 3.7 minutes for the robotic group and 6.8 minutes for the 3D-CT navigation group, P Conclusions Both technologies are safe and accurate. Robotic technology exposed patients to less fluoroscopy time, decreased time-per-screw placement and shorter hospital stay than 3D-CT navigation. Further studies are warranted to verify our results.

Background With hospital leaders and policy makers increasingly seeking ways to improve resource use, there has been heightened interest in reducing hospital length of stay (LOS) and performing spine procedures on an outpatient basis. We aimed to determine which risk factors correlated with prolonged LOS after anterior lumbar interbody fusion (ALIF). Methods Medical records for patients who underwent ALIF were retrospectively reviewed. Patients were divided into those who had extended (≥3 days) versus nonextended ( Results A total of 166 patients were included (mean age, 48.7 years). Medical comorbidities included hypertension (31.9%), diabetes (8.4%), and obesity (body mass index >30 kg/m2) (48.8%). LOS was not extended in 121 patients and extended in 45. Mean LOS was 2.2 days (95% confidence interval, 1.9–2.5). On multivariate logistic analysis, age ≥65 years (P = 0.001), preoperative benzodiazepine use (P = 0.014), 12-item Short Form mental component score (P = 0.008), estimated blood loss (P = 0.015), time to mobilization (P Conclusions As attempts are made to perform more spine procedure in ambulatory surgical centers, strict patient selection criteria are all critical in making this possible. Our results suggest that age, preoperative benzodiazepine use, higher intraoperative blood loss, delayed mobilization, and lower 12-item Short Form mental component score were correlated with increased LOS. Therefore, inpatient ALIF may be more suitable for patients with these risk factors.

BACKGROUND CONTEXT Robot-assisted spine surgery continues to rapidly develop as evidenced by the growing literature in the last few years. Numerous reports demonstrate excellent pedicle screw accuracy and early studies have explored the impact of robot-assisted spine surgery on reducing radiation exposure, length of hospital stay, operative time, and perioperative complications in comparison to conventional freehand technique. Recently, the Mazor X Stealth Edition was introduced in 2018. This robotic system integrates Medtronic's Stealth navigation technology into the Mazor X platform. It is unclear what the impact of these advancements have made on clinical outcomes. PURPOSE This is the first study to compare the outcomes and complications between the most recent iterations of the Mazor Robot systems: Mazor X and the Mazor X Stealth Edition. STUDY DESIGN/SETTING Multicenter cohort. PATIENT SAMPLE Among four different institutions, we included adult (≥18 years old) patients who underwent robot-assisted spine surgery with either the Mazor X or Stealth platforms. OUTCOME MEASURES Primary outcomes included robot time per screw, robot abandonment, screw accuracy, radiation exposure and 90-day reoperation rate. METHODS A propensity-score matching algorithm based on perioperative factors (eg, demographics, comorbidities, primary diagnosis, prior spine surgery, pelvic fixation, instrumented levels, number of planned robot screws) was employed to control for the potential selection bias between the two robotic systems. The minimum follow-up was 90 days after surgery. Chi-square/fisher exact test and t-test/ANOVA were used for categorical and continuous variables, respectively. RESULTS A total of 372 adult patients were included in this study (Stealth: 186, X: 186). The mean number of instrumented levels was 4.3. The mean number of planned robot screws was 7.8. Similar total operative time (Stealth: 197 minutes vs X: 211, p=0.591) and robot time per screw (Stealth: 6.1 minutes/screw vs X: 6.1 minutes/screw, p=0.930) occurred between cohorts. However, Stealth achieved a significantly lower robot abandonment rate (Stealth: 0% vs X: 2.2%, p=0.044). The screw accuracy for both robots was excellent (Stealth: 99.6% vs X: 99.1%, p=0.120). Stealth achieved significantly shorter radiation time than X (Stealth: 7.2 seconds/screw vs X: 10.4 seconds/screw, p 0.05). The 90-day reoperation rates were low and similar between robot cohorts. CONCLUSIONS In this multicenter study, both robot systems achieved excellent screw accuracy and low robot time per screw. However, Stealth achieved significantly less radiation exposure, lower robot abandonment rates, and reduced blood transfusion rates than Mazor X. Other factors including LOS, and 90-day reoperation rates were similar. FDA DEVICE/DRUG STATUS Medtronic Mazor X and Mazor X stealth are FDA approved in the US.

Study design Retrospective review. Objective Anterior cervical discectomy and fusion (ACDF) is a commonly performed procedure that may be complicated by airway compromise postoperatively. This life-threatening complication may necessitate reintubation and reoperation. We evaluated the cost utility of conventional postoperative x-ray. Summary of background data Studies have demonstrated minimal benefit in obtaining an x-ray on postoperative day 1, but there is some utility of postanesthesia care unit (PACU) x-rays for predicting the likelihood of reoperation. Methods We retrospectively reviewed the records of consecutive patients who underwent ACDF between September 2013 and February 2017. Patients were dichotomized into those who received PACU x-rays and those who did not (control group). Primary outcomes were reoperation, reintubation, mortality, and healthcare costs. Results Eight-hundred and fifteen patients were included in our analysis: 558 had PACU x-rays; 257 did not. In those who received PACU x-rays, mean age was 53.7 ± 11.3 years, mean levels operated on were 2.0 ± 0.79, and mean body mass index (BMI) was 30.3 ± 6.9. In those who did not, mean age was 51.8 ± 10.9 years, mean levels operated on were 1.48 ± 0.65, and mean BMI was 29.9 ± 6.3. Complications in the PACU x-ray group were reintubation-0.4%, reoperation-0.7%, and death-0.3% (due to prevertebral swelling causing airway compromise). Complications in the control group were reintubation-0.4%, reoperation-0.8%, and death-0. There were no differences between groups with respect to reoperation (p = 0.92), reintubation (p = 0.94), or mortality (p = 0.49). The mean per-patient cost was significantly higher (p = 0.009) in those who received PACU x-rays, $1031.76 ± 948.67, versus those in the control group, $700.26 ± 634.48. Mean length of stay was significantly longer in those who had PACU x-rays (p = 0.01). Conclusions Although there were no differences in reoperation, reintubation, or mortality, there was a significantly higher cost for care and hospitalization in those who received PACU x-rays. Further studies are warranted to validate the results of the presented study.Level of Evidence: 3.

Background Minimally invasive techniques in spine surgery have continued to advance as robotic technology has evolved over several generations. Although traditional techniques for placing pedicle screws are still widespread in practice, newer technology has increased the reliability of accurately placing instrumentation with smaller incisions and subsequent decreased length of stay. Additionally, advancements in planning software have improved the ability to align posterior instrumentation to assist with rod placement on multilevel constructs. Methods This paper describes the surgical techniques and operative workflow for placing pedicle screws with the latest robotic technology. The robotic platform, registration, surgical planning, and placement of instrumentation are discussed in detail. Advantages of the Mazor X Stealth Edition compared with the previous generation robot include obviating the need for K wires and eliminating the need for a percutaneous pin, as navigation is integrated into the robot. Results Our use of this new technology has been encouraging. Using the techniques described in this paper, the first 90 pedicle screws placed with the Mazor X Stealth Edition robot yielded 100% grade A accuracy on the Gertzbein-Robbins scale confirmed on immediate postoperative CT. There were no complications experienced in any case. Conclusions In our experience, this robotic technology has the potential to improve patient outcomes and is associated with advanced surgical planning compared with more traditional techniques.

Background Cortical bone trajectories (CBTs) for pedicle screw insertion can be used to stabilize the spine. Surgeons often rely on fluoroscopy or computed tomography (CT)-navigation technologies to guide screw placement. Robotic technology has potential to increase accuracy. We report our initial experience with robotic guidance for pedicle screw insertion utilizing CBTs in patients with degenerative disc disease. Methods A retrospective chart review was conducted using data for consecutive patients who underwent spinal stabilization using a posterior approach for CBTs. The newest robotic platform (Mazor X) was used in these cases. Accuracy was determined by applying the Ravi Scale: grade I (no breach or deviation), II (breach 4 mm). The results were compared with those for a historical cohort of patients who underwent CT navigation–guided pedicle screw insertion using CBTs. Results Twenty-two patients underwent robot-assisted pedicle screw placement using CBTs. A total of 92 screws were inserted across 24 spinal levels with grade I accuracy and without complications in the robotic group. Eighteen patients underwent CT-navigation for CBT pedicle screw insertion. A total of 74 screws were inserted across 19 levels, 69 of which were grade I accuracy and 5 were grade II accuracy. When comparing operative time (P = 0.97), fluoroscopy time (P = 0.8), and radiation dose (P = 0.4), no significant differences were observed between cohorts. Conclusions Robotic technology and CT-navigation technology for CBT pedicle screw insertion were safe and accurate.

The objective of this review was to understand the clinical utilization, utility, and variability in the usage of adjunctive hyperbaric oxygen therapy (HBOT). Surgical site infection is associated with high morbidity and mortality, increased health care expenditure, and decreased quality of life. With the increasing prevalence of adult spinal deformity and spinal fusion surgery, it is imperative to understand the potential benefits of adjunctive treatments. HBOT is a safe and common procedure indicated to treat various medical conditions. We conducted a literature search across 3 databases for English articles published between December 1, 2019 and December 1, 2000. Thirteen studies were included. HBOT may lessen the duration of antimicrobial therapy and mitigate instrument removal and revision surgery. The current usage indications for HBOT are supported by level III evidence for chronic osteomyelitis and level IV evidence for osteoradionecrosis. However, the same level of evidence exists to support the beneficial use of adjunctive HBOT for noncomplicated spinal infections within 2 months after surgery. When cultured, the most common organisms were Staphylococcus aureus and other low-virulence organisms. The most common treatment protocol consists of 90-minute sessions of 100% Fio2 at 2-3 atmosphere absolute with a mean of 35.3 ± 11.6 sessions for 5.2 ± 1.4 weeks. Adjunctive HBOT should be considered in select high-risk patients. Further improvements in diagnosis and categorization of spinal infections are necessary and will indelibly aid the decision making for the initiation of HBOT.

OBJECTIVE Pedicle screw insertion for stabilization after lumbar fusion surgery is commonly performed by spine surgeons. With the advent of navigation technology, the accuracy of pedicle screw insertion has increased. Robotic guidance has revolutionized the placement of pedicle screws with 2 distinct radiographic registration methods, the scan-and-plan method and CT-to-fluoroscopy method. In this study, the authors aimed to compare the accuracy and safety of these methods. METHODS A retrospective chart review was conducted at 2 centers to obtain operative data for consecutive patients who underwent robot-assisted lumbar pedicle screw placement. The newest robotic platform (Mazor X Robotic System) was used in all cases. One center used the scan-and-plan registration method, and the other used CT-to-fluoroscopy for registration. Screw accuracy was determined by applying the Gertzbein-Robbins scale. Fluoroscopic exposure times were collected from radiology reports. RESULTS Overall, 268 patients underwent pedicle screw insertion, 126 patients with scan-and-plan registration and 142 with CT-to-fluoroscopy registration. In the scan-and-plan cohort, 450 screws were inserted across 266 spinal levels (mean 1.7 ± 1.1 screws/level), with 446 (99.1%) screws classified as Gertzbein-Robbins grade A (within the pedicle) and 4 (0.9%) as grade B (< 2-mm deviation). In the CT-to-fluoroscopy cohort, 574 screws were inserted across 280 lumbar spinal levels (mean 2.05 ± 1.7 screws/ level), with 563 (98.1%) grade A screws and 11 (1.9%) grade B (p = 0.17). The scan-and-plan cohort had nonsignificantly less fluoroscopic exposure per screw than the CT-to-fluoroscopy cohort (12 ± 13 seconds vs 11.1 ± 7 seconds, p = 0.3). CONCLUSIONS Both scan-and-plan registration and CT-to-fluoroscopy registration methods were safe, accurate, and had similar fluoroscopy time exposure overall.

BACKGROUND CONTEXT As new robot technology continues to be introduced into practice, it is important for the surgeon to know how these new advances are influencing screw accuracy and outcomes. This is the first and largest multicenter study comparing two robot systems (Renaissance and Mazor X). PURPOSE To compare the screw accuracy, robot reliability and efficiency, and 1-year clinical outcomes between two robot platforms. STUDY DESIGN/SETTING Multicenter cohort. PATIENT SAMPLE Adult patients (≥18 years old) who underwent robot-assisted spine surgery with either the Renaissance or Mazor X robot system at four geographically different institutions. OUTCOME MEASURES Screw accuracy, robot time per screw, robot abandonment, and 1-year clinical outcomes between two robot systems. METHODS In this multicenter study, we performed a propensity-score matching algorithm based on perioperative factors (eg, demographics, comorbidities, indications for surgery, prior spine surgery, pelvic fixation, instrumented levels, planned robot screws) to control for the potential selection bias between the two robotic systems. Chi-square/fisher exact test and t-test/ANOVA were used for categorical and continuous variables, respectively. RESULTS A total of 400 adult patients were included in this study (200 Renaissance, 200 X). The most common preoperative diagnoses included high grade spondylolisthesis (47.5%), degenerative scoliosis (20.3%), and degenerative disc disease (15.8%). The mean number of instrumented levels was 4.0. The mean number of planned robot screws was 7.4. The screw accuracy for both robots were excellent (X: 99.0% vs Renaissance: 98.1%, p=0.078). The Mazor X achieved a significantly shorter robot time per screw (X: 5.8 minutes vs Renaissance: 7.2 minutes, p=0.016). Furthermore, the robot abandonment rate due to registration issues was significantly higher for the Renaissance (4.5%) than the X (0.5%, p=0.010). Non-robot related complications such as dura tear, motor/sensory deficits, blood transfusion, and return to the OR during same admission was similar between robots (p>0.05). Interestingly the LOS was nearly a day shorter for the X (4.7 days) than the Renaissance (5.5 days, p CONCLUSIONS Our multicenter study demonstrates that the Mazor X achieves a significantly lower robot time spent per screw, higher robot reliability, and potentially lower overall costs given the nearly 1-day reduction in hospital length of stay. These findings are likely the result of the recent advancements in Mazor X technology, particularly the cutting edge preoperative planning software. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Background Bilateral extracavitary approach (BECA) is an option for decompression cases that require a more extended ventral approach. The clear advantage is increased accessibility to the most ventral aspects of the spine from a bilateral perspective. Objective To assess the safety and efficacy of thoracic and thoracolumbar decompression and/or reconstruction from BECA. Methods A retrospective chart review was performed reviewing all patients who underwent BECA for thoracolumbar decompression from 2003 to 2012 at our institution. We recorded patient baseline characteristics, physical exam, surgical indications, perioperative interventions, and outcomes. Results We performed 82 lateral extracavitary approaches and 10 BECAs. BECA indications included neoplasm, infection, and kyphotic deformity. Average patient age was 58 yr; 80% of BECA patients were male. Estimated blood loss was typically 1 to 3 L. Average length of stay postoperative was 12 d. Two patients required revisions; one for infection and one for revision of misplaced hardware. Eight patients improved at least one grade on the American Spinal Injury Association Impairment Scale (ASIA) or was originally ASIA E. Two patients declined 1 to 2 ASIA grades. Average length of follow-up was 16.8 mo. Conclusion BECA is an efficient technique with acceptable complication rates and similar risks to unilateral approaches. It should be considered when extensive bilateral decompression and/or reconstruction of the anterior thoracic or thoracolumbar spine is required.

Traditionally, lateral mass screws (LMSs) have been the mainstay of posterior fixation in the subaxial spine. Although LMSs provide adequate fixation, cervical pedicle screws (CPSs) facilitate high fusion rates (90.5%) and provide for greater bone purchase, better reduction, lower rates of screw loosening or pull out, 2 times greater biomechanical advantage, superior stabilization, decreased development of pseudarthrosis, and decreased revision surgeries compared to LMSs.1-4 In addition, CPSs can be a powerful bail-out option after lateral mass construct failure. Navigation-guided CPS placement has been reported to have an accuracy of 90.3%.5 Navigation has the added advantage of mitigating screw malposition for the placement of CPS because of the smaller pedicle sizes and variability in cervical anatomy.1,3,6 The potential risks of subaxial CPS placement include the risks of vertebral artery injury, spinal cord injury, and injury to adjacent neurovasculature.2 The overall radiographic breach rate with intraoperative imaging is reported to range from 2.9% of 22.9%, with the majority of breaches occurring in the lateral direction.7,8 Despite radiographic breaches, the occurrence of nerve root injury (0.31% per screw), vertebral artery injury (0.15% per screw), and spinal cord injury (0% per screw) is rare.3,7 Here, we demonstrate navigation-assisted C1-C2 posterior fusion, with combined C1 LMSs and C2 pedicle screws with subaxial pedicle screw revision of prior failed instrumentation.3 The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary.

Robot-assisted pedicle screw insertion has been slowly gaining popularity in the spine surgery community. In previous studies, robotics has been shown to increase accuracy and reduce complication rates compared to other navigation technologies, although those studies have been conducted using traditional trajectories for pedicle screw insertion. We present a surgical video in which a robotics system (Mazor X; Mazor Robotics Ltd, Caesarea, Israel) was used to create cortical bone trajectories for the insertion of the screws. The patient in this case is a 52-yr-old woman with severe L4-5 disc herniation requiring a transforaminal interbody fusion with the insertion of pedicle screws. The robotic system's scan-and-plan technique was utilized, in which an intraoperative computed tomography (CT) scan generates a real-time operative plan. Other techniques for inserting pedicle screws using cortical bone trajectories include CT navigation and fluoroscopic guidance. These techniques allow the surgeon to manually direct the screw under precise guidance in multiple planes, although the surgeon is still using all 6 degrees of freedom the human hand provides. With robotic guidance, a pilot hole is drilled, which eliminates 4 of 6 degrees of freedom, which can potentially reduce the risk of misplaced screws. To our knowledge, this is the first video demonstrating pedicle screw insertion through cortical bone trajectories using robotic guidance. Future studies are warranted to compare cortical bone trajectory insertion using different navigation techniques to determine the long-term efficacy of each technique. The patient gave informed consent for surgery and video recording. Institutional review board approval was deemed unnecessary.

Background: COVID-19 has had a significant impact on the economy, health care, and society as a whole. To prevent the spread of infection, local governments across the United States issued mandatory lockdowns and stay-at-home orders. In the surgical world, elective cases ceased to help "flatten the curve" and prevent the infection from spreading to hospital staff and patients. We explored the effect of the cancellation of these procedures on trainee operative experience at our high-volume, multihospital neurosurgical practice. Methods: Our department cancelled all elective cases starting March 16, 2020, and resumed elective surgical and endovascular procedures on May 11, 2020. We retrospectively reviewed case volumes for 54 days prelockdown and 54 days postlockdown to evaluate the extent of the decrease in surgical volume at our institution. Procedure data were collected and then divided into cranial, spine, functional, peripheral nerve, pediatrics, and endovascular categories. Results: Mean total cases per day in the prelockdown group were 12.26 ± 7.7, whereas in the postlockdown group, this dropped to 7.78 ± 5.5 (P = 0.01). In the spine category, mean cases per day in the prelockdown group were 3.13 ± 2.63;in the postlockdown group, this dropped to 0.96 ± 1.36 (P < 0.001). In the functional category, mean cases per day in the prelockdown group were 1.31 ± 1.51, whereas in the postlockdown group, this dropped to 0.11 ± 0.42 (P < 0.001). For cranial (P = 0.245), peripheral nerve (P = 0.16), pediatrics (P = 0.34), and endovascular (P = 0.48) cases, the volumes dropped but were not statistically significant decreases. Conclusion: The impact of this outbreak on operative training does appear to be significant based solely on statistics. Although the drop in case volumes during this time can be accounted for by the pandemic, it is important to understand that this is a multifactorial effect. Further studies are needed for these results to be generalizable and to fully understand the effect this pandemic has had on trainee operative experience. [ABSTRACT FROM AUTHOR] Copyright of Surgical Neurology International is the property of Scientific Scholar LLC and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

OBJECTIVE In 2009, Santoni and colleagues described a novel technique of posterior instrumentation; the cortical bone trajectory (CBT) was described as a caudocephalad and medial-to-lateral trajectory. Reported indications for CBT fixation include patients with osteoporosis, single-level degenerative disease, or adjacent-segment disease (ASD). In cases of revision surgery, it is technically possible and beneficial to place a traditional pedicle screw and a CBT screw at the same spinal level and side. It remains unclear as to the feasibility of placing both a traditional and a CBT screw at all levels of the lumbar spine and with varying trajectories of the preexisting traditional pedicle screws. Therefore, the authors conducted a study to radiographically assess the feasibility of using CBT and traditional pedicle screws at the same level in a large patient population. METHODS Using a 3D Spine Navigation WorkStation, the authors assessed 47 lumbar spine CT scans. These images were obtained from 2 disparate groups of patients: those who had previously undergone traditional pedicle instrumentation (prior surgery group) and those who had not (no prior surgery group). The authors virtually placed traditional pedicle and CBT screws at each lumbar level bilaterally. It was then determined if the dual trajectories were feasible, as defined by the presence or absence of a collision of the screw trajectories based on 3D imaging. RESULTS Overall, the authors evaluated 47 patients and were able to successfully plan dual trajectories in 50% of the pedicles. The no prior surgery group, compared with the prior surgery group, had a significantly greater success rate for dual trajectories. This difference was most significant in the lower lumbar levels (L3–5) where the prior instrumented group had success rates lower than 40% compared with the no prior surgery group's success rate, which was greater than 70%. There was a significant difference between each lumbar level in the lower spine. CONCLUSIONS There is a significant difference in the feasibility of planning CBT screws in patients who have undergone prior pedicle instrumentation compared with placing CBT and traditional pedicle screws simultaneously, but dual trajectory pedicle screws are a feasible option for posterior lumbar spinal instrumentation, especially as a de novo option in osteoporotic patients or in patients with ASD who underwent previous pedicle instrumentation. Ultimately, the practical clinical utility and biomechanical effects on the spine and instrumentation construct would require additional study.