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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.

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.

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.

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.

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.

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.

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.

Carotid-cavernous fistula was one of the first intracranial vascular lesions to be recognized. This paper focuses on the historical progression of our understanding of the condition and its symptomatology—from the initial hypothesis of ophthalmic artery aneurysm as the cause of pulsating exophthalmos to the recognition and acceptance of fistulas between the carotid arterial system and cavernous sinus as the true etiology. The authors also discuss the advancements in treatment from Benjamin Travers' early common carotid ligation and wooden compression methods to today's endovascular approaches.

Background Surgical-site infections (SSIs) are a major cause of morbidity and mortality, increasing the length and cost of hospitalization. In patients undergoing spine surgery, there are limited large-scale data on patient-specific risk factors for SSIs. Methods The American College of Surgeons National Surgical Quality Improvement Program database was reviewed for all spinal operations between 2006 and 2012. The rates of 30-day SSIs were calculated, and univariate analysis of selected preoperative risk factors was performed. Multivariate analysis was then used to identify independent predictors of SSIs. Results A total of 1110 of the 60,179 patients (1.84%) had a postoperative wound infection. There were 527 (0.87%) deep and 590 (0.98%) superficial infections. Patients with infections had greater rates of sepsis, longer lengths of stay, and more return visits to the operating room. Independent predictors of infection were female sex, inpatient status, insulin-dependent diabetes, preoperative steroid use greater than 10 days, hematocrit less than 35, body mass index greater than 30, wound class, American Society of Anesthesiologists class, and operative duration. Conclusions Analysis of a large national patient database revealed many independent risk factors for SSIs after spinal surgery. Some of these risk factors can be modified preoperatively to reduce the risk of postoperative infection.

Background Subdural grid (SDG) electrodes have been the gold standard of invasive monitoring in medically refractory epilepsy; however, in some centers, application of SDGs has been reduced by the progressive application of stereoelectroencephalography (SEEG). This study reviews the efficacy of SDG electrode monitoring after the incorporation of the SEEG methodology at our institution. Methods We retrospectively reviewed 102 patients undergoing intracranial monitoring via SDG electrodes during the years 2010–2013 at our institution. The series includes all patients who underwent SDG placement after the incorporation of SEEG in our extraoperative invasive monitoring armamentarium. Results Average patient age was 29.9 years old; the series included 31 pediatric patients. There were 49 male patients and 53 female patients. The mean length of follow-up was 21.5 months. The epileptogenic zone was localized in 99 (97%) patients. Surgical resection was performed in 84 patients, and 70% experienced Engel class I freedom from seizures. Conclusions Invasive monitoring via SDG electrodes continues to be an efficacious option for select patients with medically refractory epilepsy, mainly when the hypothetical epileptogenic zone is anatomically restricted to superficial cortical areas and in close relation with eloquent cortex. This is the first report of epilepsy outcomes after SDG monitoring at a center that also performs SEEG monitoring. Our results suggest a complementary benefit of performing both techniques at 1 institution.

SummaryObjective Stereo-electroencephalography (SEEG) is a procedure performed for patients with intractable epilepsy in order to anatomically define the epileptogenic zone (EZ) and the possible related functional cortical areas. By avoiding the need for large craniotomies and due to its intrinsic precision placement features, SEEG may be associated with fewer complications. Nevertheless, intracerebral electrodes have gained a reputation of excessive invasiveness, with a “relatively high morbidity” associated with their placement. A systematic literature review and meta-analysis of SEEG complications has not been previously performed. The goal of this study is to quantitatively review the incidence of various surgical complications associated with SEEG electrode implantation in the literature and to provide a summary estimate. This will allow physicians to accurately counsel their patients about the potential complications related to this method of extraoperative invasive monitoring. Methods The systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We conducted MEDLINE, Scopus, and Web of Science database searches with the search algorithm. We analyzed complication rates using a fixed-effects model with inverse variance weighting. Calculations for the meta-analysis and construction of forest plots were completed using an established spreadsheet. The principal summary measures were the effect summary value and 95% confidence intervals (CIs). Results The initial 1,901 retrieved citations were reviewed. After removing 787 duplicates, the titles and abstracts of 1,114 publications were screened. At this stage, studies that did not mention the absence or presence of complications following SEEG or that did not fulfill the inclusion criteria in any manner were excluded. After excluding 1,057 citations, the full text was assessed in the resulting 57 articles for eligibility criteria. The most common complications were hemorrhagic (pooled prevalence 1.0%, 95% confidence interval [CI] 0.6–1.4%) or infectious (pooled prevalence 0.8%, 95% CI 0.3–1.2%). Five mortalities were identified (pooled prevalence 0.3%, 95% CI −0.1–0.6%). Overall, our analysis identified 121 surgical complications related to SEEG insertion and monitoring (pooled prevalence 1.3%, 95% CI 0.9–1.7%). Significance This review represents a comprehensive estimation of the actual incidence of complications related to SEEG. We report a rate substantially lower than the complication rates reported for other methods of extraoperative invasive monitoring. These data should alleviate the concerns of some regarding the safety of the “stereotactic” method, allowing a better decision process among the different methods of invasive monitoring and ameliorating the fear associated with the placement of depth electrodes.

OBJECTIVESignificant blood loss and coagulopathy are often encountered during adult spinal deformity (ASD) surgery, and the optimal intraoperative transfusion algorithm is debatable. Rotational thromboelastometry (ROTEM), a functional viscoelastometric method for real-time hemostasis testing, may allow early identification of coagulopathy and improve transfusion practices. The objective of this study was to investigate the effect of ROTEM-guided blood product management on perioperative blood loss and transfusion requirements in ASD patients undergoing correction with pedicle subtraction osteotomy (PSO).METHODSThe authors retrospectively reviewed patients with ASD who underwent single-level lumbar PSO at the University of Virginia Health System. All patients who received ROTEM-guided blood product transfusion between 2015 and 2017 were matched in a 1:1 ratio to a historical cohort treated using conventional laboratory testing (control group). Co-primary outcomes were intraoperative estimated blood loss (EBL) and total blood product transfusion volume. Secondary outcomes were perioperative transfusion requirements and postoperative subfascial drain output.RESULTSThe matched groups (ROTEM and control) comprised 17 patients each. Comparison of matched group baseline characteristics demonstrated differences in female sex and total intraoperative dose of intravenous tranexamic acid (TXA). Although EBL was comparable between ROTEM versus control (3200.00 ± 2106.24 ml vs 3874.12 ± 2224.22 ml, p = 0.36), there was a small to medium effect size (Cohen’s d = 0.31) on EBL reduction with ROTEM. The ROTEM group had less total blood product transfusion volume (1624.18 ± 1774.79 ml vs 2810.88 ± 1847.46 ml, p = 0.02), and the effect size was medium to large (Cohen’s d = 0.66). This difference was no longer significant after adjusting for TXA (β = −0.18, 95% confidence interval [CI] −1995.78 to 671.64, p = 0.32). More cryoprecipitate and less fresh frozen plasma (FFP) were transfused in the ROTEM group patients (cryoprecipitate units: 1.24 ± 1.20 vs 0.53 ± 1.01, p = 0.03; FFP volume: 119.76 ± 230.82 ml vs 673.06 ± 627.08 ml, p < 0.01), and this remained significant after adjusting for TXA (cryoprecipitate units: β = 0.39, 95% CI 0.05 to 1.73, p = 0.04; FFP volume: β = −0.41, 95% CI −772.55 to −76.30, p = 0.02). Drain output was lower in the ROTEM group and remained significant after adjusting for TXA.CONCLUSIONSFor ASD patients treated using lumbar PSO, more cryoprecipitate and less FFP were transfused in the ROTEM group compared to the control group. These preliminary findings suggest ROTEM-guided therapy may allow early identification of hypofibrinogenemia, and aggressive management of this may reduce blood loss and total blood product transfusion volume. Additional prospective studies of larger cohorts are warranted to identify the appropriate subset of ASD patients who may benefit from intraoperative ROTEM analysis.

The aims of this retrospective cohort study were to 1) identify new alignment risk factors for proximal junctional kyphosis (PJK) in adult spinal deformity (ASD) patients with lower thoracic upper instrumented vertebra (UIV) and 2) determine the effect of junctional tethers on PJK and UIV alignment.We analyzed consecutive ASD patients who underwent posterior instrumented fusion with lower thoracic UIV (T9-T11). Posteriorly anchored junctional tethers were used more recently for ligamentous augmentation to prevent PJK. In addition to regional and global parameters, upper segmental lumbar lordosis (ULL) versus lower segmental lumbar lordosis and UIV angle (measured from UIV inferior endplate to horizontal) were assessed. Primary outcome of PJK was defined as proximal junctional angle10° and10° greater than the corresponding preoperative measurement. Univariable and multivariable analyses were performed.The study cohort comprised 120 ASD patients (mean age, 67 years) with minimum 1-year follow-up. Preoperative ULL (P = 0.034) and UIV angle (P = 0.026) were associated with PJK. No independent preoperative alignment risk factors of PJK were identified in multivariable analysis. Tether use was protective against PJK (odds ratio, 0.063 [0.016-0.247]; P0.001). PJK in tethered patients was more common with greater postoperative ULL (P = 0.047) and UIV angle (P = 0.026).Junctional tethers significantly reduced PJK in ASD patients with lower thoracic UIV. In tethered patients, PJK was more common with greater postoperative lordosis of the upper lumbar spine and greater UIV angle. This finding suggests potential benefit of tethers to mitigate effects of segmental lumbar and focal UIV malalignment that may occur after deformity surgery.

Tranexamic acid (TXA) is an antifibrinolytic agent with demonstrated efficacy in reducing blood loss when administered systemically. However, in patients with contraindications to systemic or intravenous TXA, topical TXA (tTXA) has been shown to reduce perioperative blood loss, with some studies suggesting equivalence compared to systemic TXA. However, these studies have been conducted in healthy cohorts without contraindications to systemic TXA. In the surgical management of adult spinal deformity (ASD), comorbid disease is commonly encountered and may preclude use of systemic TXA. In this subset of patients with ASD who have contraindications for systemic TXA, use of tTXA has not been reported.The primary objective of this study was to conduct a systematic review on the use of tTXA in spine surgery and to present the authors’ initial experience with tTXA as a novel hemostatic technique for 2 patients with medically complex ASD. Both patients had contraindications to systemic TXA use and underwent high-risk, long-segment fusion operations for correction of ASD. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to obtain studies related to spine surgery and tTXA from the National Institutes of Health PubMed (www.pubmed.gov) database. Criteria for final selection included a demonstration of quantitative data regarding operative or postoperative blood loss with the use of tTXA, and selection criteria were met by 6 articles.Topical TXA may offer a potential therapeutic role in reducing intra- and postoperative blood loss following long-segment spinal fusion surgeries, particularly for medically complex patients with contraindications to systemic TXA. It is reasonable to consider the use of tTXA as a salvage technique in complex high-risk patients with contraindications to systemic TXA, although further research is needed to delineate safety, magnitude of benefit, and optimization of dosing.

Restoration of spinal alignment and balance is a major goal of adult scoliosis surgery. In the past, sagittal alignment has been emphasized and was shown to have the greatest impact on functional outcomes. However, recent evidence suggests the impact of coronal imbalance on pain and functional outcomes has likely been underestimated.1,2 In addition, iatrogenic coronal imbalance may be common and frequently results from inadequate correction of the lumbosacral fractional curve.2,3 The "kickstand rod" is a recently described technique to achieve and maintain significant coronal-plane correction.4 Also, of secondary benefit, the kickstand rod may function as an accessory supplemental rod to offload stress and bolster primary instrumentation. This may reduce occurrence of rod fracture (RF) or pseudarthrosis (PA).5 Briefly, this technique involves positioning the kickstand rod on the side of coronal imbalance (along the major curve concavity or fractional curve convexity in our video demonstration). The kickstand rod spans the thoracolumbar junction proximally to the pelvis distally and is secured with an additional iliac screw placed just superior to the primary iliac screw. By using the iliac wing as a base, powerful distraction forces can reduce the major curve to achieve more normal coronal balance. This operative video illustrates the technical nuances of utilizing the kickstand rod technique for correction of severe lumbar scoliosis and coronal malalignment in a 60-yr-old male patient. Alignment correction was achieved and maintained without evidence of RF/PA after nearly 6 mo postoperatively. The patient gave informed consent for surgery and to use imaging for medical publication.

Proximal junctional kyphosis (PJK) is a common problem after multilevel spine instrumentation for adult spinal deformity. Various anti-PJK techniques such as junctional tethers for ligamentous augmentation have been proposed. We present an operative video demonstrating technical nuances of junctional tether "weave" application. A 70-yr-old male with prior L2-S1 instrumented fusion presented with worsening back pain and posture. Imaging demonstrated pathological loss of lumbar lordosis (flat back deformity), proximal junctional failure, and pseudarthrosis. The patient had severe global and segmental sagittal malalignment, with sagittal vertical axis (SVA, C7-plumbline) measuring 22.3 cm, pelvic incidence (PI) 55°, lumbar lordosis (LL) 8° in kyphosis, pelvic tilt (PT) 30°, and thoracic kyphosis (TK) 6°. The patient gave informed consent for surgery and use of imaging for medical publication. Briefly, surgery first involved re-instrumentation with bilateral pedicle screws from T10 to S1. After right-sided iliac screw fixation (left-sided iliac screw fixation was not performed due to extensive prior iliac crest bone graft harvesting), we then completed a L2-3 Smith-Petersen osteotomy, extended L4 pedicle subtraction osteotomy, and L3-4 interbody arthrodesis with a 12° lordotic cage (9 × 14 × 40 mm). Cobalt Chromium rods were placed spanning the instrumentation bilaterally, and accessory supplemental rods spanning the PSO were attached. An anti-PJK junctional tether "weave" was then implemented using 4.5 mm polyethylene tape (Mersilene tape [Ethicon, Somerville, New Jersey]). Postoperative imaging demonstrated improved alignment (SVA 2.8 cm, PI 55°, LL 53°, PT 25°, TK 45°) and no significant neurological complications occurred during convalescence or at 6 mo postop.

OBJECTIVEFixed sagittal spinal malalignment is a common problem in adult spinal deformity (ASD). Various three-column osteotomy techniques, including the extended pedicle subtraction osteotomy (ePSO), may correct global and regional malalignment in this patient population. In contrast to the number of reports on traditional PSO (Schwab grade 3 osteotomy), there is limited literature on the outcomes of ePSO (Schwab grade 4 osteotomy) in ASD surgery. The objective of this retrospective study was to provide focused investigation of radiographic outcomes and complications of single-level lumbar ePSO for ASD patients with fixed sagittal malalignment.METHODSConsecutive ASD patients in whom sagittal malalignment had been treated with single-level lumbar ePSO at the authors’ institution between 2010 and 2015 were analyzed, and those with a minimum 2-year follow-up were included in the study. Radiographic analyses included assessments of segmental lordosis through the ePSO site (sagittal Cobb angle measured from the superior endplate of the vertebra above and inferior endplate of the vertebra below the ePSO), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence and LL mismatch, thoracic kyphosis (TK), and sagittal vertical axis (SVA) on standing long-cassette radiographs. Complications were analyzed for the entire group.RESULTSAmong 71 potentially eligible patients, 55 (77%) had a minimum 2-year follow-up and were included in the study. Overall, the average postoperative increases in ePSO segmental lordosis and overall LL were 41° ± 14° (range 7°–69°, p < 0.001) and 38° ± 11° (range 9°–58°, p < 0.001), respectively. The average SVA improvement was 13 ± 7 cm (range of correction: −33.6 to 3.4 cm, p < 0.001). These measurements were maintained when comparing early postoperative to last follow-up values, respectively (mean follow-up 52 months, range 26–97 months): ePSO segmental lordosis, 34° vs 33°, p = 0.270; LL, 47.3° vs 46.7°, p = 0.339; and SVA, 4 vs 5 cm, p = 0.330. Rod fracture (RF) at the ePSO site occurred in 18.2% (10/55) of patients, and pseudarthrosis (PA) at the ePSO site was confirmed by CT imaging or during rod revision surgery in 14.5% (8/55) of patients. Accessory supplemental rods across the ePSO site, a more recently employed technique, significantly reduced the occurrence of RF or PA on univariate (p = 0.004) and multivariable (OR 0.062, 95% CI 0.007–0.553, p = 0.013) analyses; this effect approached statistical significance on Kaplan-Meier analysis (p = 0.053, log-rank test). Interbody cage placement at the ePSO site resulted in greater ePSO segmental lordosis correction (45° vs 35°, p = 0.007) without significant change in RF or PA (p = 0.304). Transient and persistent motor deficits occurred in 14.5% (8/55) and 1.8% (1/55) of patients, respectively.CONCLUSIONSExtended PSO is an effective technique to correct fixed sagittal malalignment for ASD. In comparison to traditional PSO techniques, ePSO may allow greater focal correction with comparable complication rates, especially with interbody cage placement at the ePSO site and the use of accessory supplemental rods.

Pedicle subtraction osteotomy (PSO) is an effective technique to correct fixed sagittal malalignment. A variation of this technique, the "trans-discal" or "extended" PSO (Schwab grade IV osteotomy), involves extending the posterior wedge resection of the index vertebra to include the superior adjacent disc for radical discectomy. The posterior wedge may be resected in asymmetric fashion to correct concurrent global coronal malalignment.This video illustrates the technical nuances of an extended asymmetrical lumbar PSO for adult spinal deformity. A 62-yr-old female with multiple prior lumbar fusions presented with worsening back pain and posture. Preoperative scoliosis X-rays demonstrated severe global sagittal and coronal malalignment (sagittal vertical axis [SVA, C7-plumbline] of 13.5 cm, pelvic incidence [PI] of 60°, lumbar lordosis [LL] of 14° [in kyphosis], pelvic tilt [PT] of 61°, thoracic kyphosis [TK] of 18°, and rightward coronal shift of 9.3 cm). The patient gave informed consent to surgery and for use of her imaging for medical publication. Briefly, surgery first involved transpedicular instrumentation from T10 to S1 with bilateral iliac screw fixation, and then T11-12 and T12-L1 Smith-Petersen osteotomies were performed. Next, an extended asymmetrical L4 PSO was performed and a 12° lordotic cage (9 × 14 × 40 mm) was placed at the PSO defect. Rods were placed from T10 to iliac bilaterally, and accessory supplemental rods spanning the PSO were attached. Postoperative scoliosis X-rays demonstrated improved alignment: SVA 5.5 cm, PI 60°, LL 55°, PT 36°, TK 37°, and 3.7 cm of rightward coronal shift. The patient had uneventful recovery.

OBJECTIVEInsular epilepsy is relatively rare; however, exploring the insular cortex when preoperative workup raises the suspicion of insular epilepsy is of paramount importance for accurate localization of the epileptogenic zone and achievement of seizure freedom. The authors review their clinical experience with stereoelectroencephalography (SEEG) electrode implantation in patients with medically intractable epilepsy and suspected insular involvement.METHODSA total of 198 consecutive cases in which patients underwent SEEG implantation with a total of 1556 electrodes between June 2009 and April 2013 were reviewed. The authors identified patients with suspected insular involvement based on seizure semiology, scalp EEG data, and preoperative imaging (MRI, PET, and SPECT or magnetoencephalography [MEG]). Patients with at least 1 insular electrode based on the postoperative 3D reconstruction of CT fused with the preoperative MRI were included.RESULTSOne hundred thirty-five patients with suspected insular epilepsy underwent insular implantation of a total of 303 electrodes (1–6 insular electrodes per patient) with a total of 562 contacts. Two hundred sixty-eight electrodes (88.5%) were implanted orthogonally through the frontoparietal or temporal operculum (420 contacts). Thirty-five electrodes (11.5%) were implanted by means of an oblique trajectory either through a frontal or a parietal entry point (142 contacts). Nineteen patients (14.07%) had insular electrodes placed bilaterally. Twenty-three patients (17.04% of the insular implantation group and 11.6% of the whole SEEG cohort) were confirmed by SEEG to have ictal onset zones in the insula. None of the patients experienced any intracerebral hemorrhage related to the insular electrodes. After insular resection, 5 patients (33.3%) had Engel Class I outcomes, 6 patients (40%) had Engel Class II, 3 patients (20%) had Engel Class III, and 1 patient (6.66%) had Engel Class IV.CONCLUSIONSInsula exploration with stereotactically placed depth electrodes is a safe technique. Orthogonal electrodes are implanted when the hypothesis suggests opercular involvement; however, oblique electrodes allow a higher insular sampling rate.

Cerebellar hemorrhage (CH) is a rare but devastating complication following spine surgery. It is associated with a compromise to dura integrity and typically has a delayed post-operative onset. Here, we describe a patient who suffered a CH that presented with a generalized tonic-clonic (GTC) seizure immediately after a revision lumbar fusion. The patient did not regain consciousness from anesthesia prior to the hemorrhage. There are no reports indicating that CHs can occur abruptly following a spine surgery. This case outlines the importance of remaining vigilant for signs of CH immediately after surgery.

SEEG is a method and technique which is used for accurate, invasive recording of seizure activity via three dimensional recordings. In epilepsy patients who are deemed appropriate candidates for invasive recordings, the decision to monitor is made between the subdural grids versus SEEG. Invasive neuromonitoring for epilepsy is pursued in patients with complex, medically refractory epilepsy. The goal of invasive monitoring is to offer resective surgery with the hope of allowing seizure freedom. SEEG's advantages include access to deep cortical structures, an ability to localize the epileptogenic zone (EZ) when subdural grids have failed to do so, and in patients with non-lesional extra-temporal epilepsies. In this manuscript, we present a succinct historical overview of the SEEG and report on our experience with frameless stereotaxy under robotic. An imperative step of SEEG insertion is planning the electrode trajectories. In order to most effectively record ictal activity via SEEG trajectories should be planned based upon a hypothesis of where the seizure activity originates the presumed epileptogenic zone (EZ). The EZ hypothesis is based on a standardized preoperative workup including video-EEG monitoring, MRI (magnetic resonance imaging), PET (positron emission tomography), ictal SPECT (Single-photon emission computed tomography), and neuropsychological assessment. Using a suspected EZ, SEEG electrodes can be placed minimally invasively yet maintain accuracy and precision. Clinical results showed the ability to localize the EZ in 78% of difficult to localize epileptic patients.(1).

BACKGROUND In some cases of refractory epilepsy, hemispherectomy is the final invasive treatment option. However, predictors of postoperative hemiparesis in these patients have not been widely studied. OBJECTIVE To investigate how the volumetric analysis of cerebral peduncles and cerebellar hemispheres in patients who have undergone hemispherectomy may determine prognostic implications for postoperative hemiparesis. METHODS Twenty-two patients who underwent hemispherectomy at our institution were retrospectively included. Using iPlan/BrainLAB (BrainLAB, Feldkirchen, Germany) imaging software and a semiautomatic voxel-based segmentation method, we calculated the preoperative cerebral peduncle and cerebellar hemisphere volumes. Cerebral peduncle and cerebellar hemisphere ratios were compared between patients with worsened or unchanged/better hemiparesis postoperatively. RESULTS The ratios of ipsilateral/contralateral cerebral peduncles (0.570 vs 0.828; P = .02) and contralateral/ipsilateral cerebellar hemispheres (0.885 vs 1.031; P = .009) were significantly lower in patients who had unchanged/improved hemiparesis postoperatively compared with patients who had worsened hemiparesis. Relative risk of worsening hemiparesis was significantly higher in patients with a cerebral peduncle ratio

BACKGROUND CONTEXT Various three-column osteotomy techniques, including the extended pedicle subtraction osteotomy (ePSO), may correct global and regional malalignment in adult spinal deformity (ASD) patients. In contrast to the traditional PSO (Schwab grade 3 osteotomy), there is limited literature reporting outcomes for ePSO (Schwab grade 4 osteotomy) in ASD surgery. PURPOSE The objective of this study was to provide focused investigation of radiographic outcomes and complications for patients undergoing single-level lumbar ePSO for ASD. STUDY DESIGN/SETTING Retrospective review of prospectively-maintained, single-center, multisurgeon database of consecutive ASD patients. PATIENT SAMPLE Consecutive ASD patients. OUTCOME MEASURES Radiographic parameters (including segmental lordosis through the ePSO site) and associated complications. METHODS Fifty-five consecutive ASD patients in whom sagittal malalignment was treated with single-level lumbar ePSO at our institution between 2010 and 2015 were analyzed. Radiographic analyses included assessment of segmental lordosis through the ePSO site (sagittal Cobb's angle measured from the superior endplate of the vertebra above and inferior endplate of the vertebra below the ePSO), lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence and LL mismatch, thoracic kyphosis (TK), and sagittal vertical axis (SVA) on standing long-cassette radiographs. Patients with minimum 2-year follow-up were included and complications were analyzed for the entire group. RESULTS Overall, the average postoperative increase in ePSO segmental lordosis and overall LL was 41°±14° (range: 7°–69°, p CONCLUSIONS ePSO is an effective technique to correct sagittal malalignment in ASD. In comparison to traditional PSO techniques, ePSO may allow greater focal correction with comparable complication rates, especially with interbody cage placement at the ePSO site and use of accessory supplemental rods.

Background Knowledge of frontal sinus morphometry is important in bifrontal, pterional, orbitozygomatic, and supraorbital craniotomies. Inadvertent frontal sinus violation can lead to infection, cerebrospinal fluid fistula, and mucocele formation. In particular, knowledge of anatomy in relation to surgically relevant landmarks can help surgeons perform these procedures more precisely and safely. We performed a descriptive radiographic analysis to better understand variations in frontal sinus anatomy. Methods Using 3-dimensional reconstructive software, we analyzed 162 normal cranial computerized tomographic angiograms (from 80 men and 82 women). A line between the supraorbital notches (SONs) was used as a horizontal reference line (HRL). We recorded the maximum sinus height and width from the HRL and midline, respectively. In addition, sinus width was measured in relation to the SON at 0, 1, and 2 cm above the HRL. Results The mean maximal sinus height from the HRL was 1.8 cm. The mean maximum sinus width was 2.6 cm (right and left) from midline and 0.46 cm (right) and 0.49 cm (left) from the SON. Less than 11% of sinuses were lateral to the SON at 2.0 cm above the HRL and 1.5 cm lateral to the SON at 1.0 cm above the HRL. Conclusions Planned surgical corridors >1.5 cm lateral to the SON and/or >3.0 cm above the HRL are most likely to avoid the frontal sinus based on our radiographic measurements of normal sinus anatomy. Careful radiographic study and appropriate planning for more medial and/or inferior corridors is suggested.

INTRODUCTION:Stereotacticelectroencephalography (SEEG) is a procedure performed to define the epileptogenic zone in medically refractory epilepsy patients. Despite not requiring a craniotomy, intracerebral electrodes have gained a reputation of a “relatively high morbidity” associated with their pla