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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.

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.

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 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.

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 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.

BACKGROUND CONTEXT Surgical correction of adult spinal deformity (ASD) is often associated with significant blood loss and coagulopathy. Optimal intraoperative transfusion algorithm remains debatable. Rotational thromboelastometry (ROTEM), a functional viscoelastometric method for real-time hemostasis testing, may allow early identification of coagulopathy, and hence improve transfusion practices during surgery. PURPOSE To investigate the effects of ROTEM-guided therapy on intraoperative estimated blood loss (EBL) and transfusion requirements in patients who underwent pedicle subtraction osteotomy (PSO) for ASD. STUDY DESIGN/SETTING Retrospective chart review of a prospectively maintained, single-center, multisurgeon database. PATIENT SAMPLE Consecutive ASD patients. OUTCOME MEASURES Primary outcomes: intraoperative EBL and total volume of blood product transfused. Secondary outcomes: packed red blood cells (pRBC), platelets, cryoprecipitate, and fresh frozen plasma (FFP) transfused during surgery. METHODS All ASD patients who underwent single-level lumbar PSO with ROTEM-guided transfusion at our institution were matched in a 1:1 ratio to a historical cohort with the conventional clinical and point-of-care (POC) transfusion algorithm. Covariates for matching were age, body mass index, revision operation status, number of instrumented levels, number of transforaminal lumbar interbody fusions, number of Smith-Petersen osteotomies, and preoperative hemoglobin. RESULTS The matched groups comprised 17 patients each, and comparison of baseline demographic and surgical parameters demonstrated more women (p=.04) and a higher total intraoperative dose of intravenous tranexamic acid (TXA) administered (p=.03) in the ROTEM group. Although not significant, EBL was lower in the ROTEM group (3200.00±2106.24vs. 3874.12±2224.22 mL; p=.36), with small-to-medium effect size (Cohen's d=0.31). Prior to adjusting for TXA, ROTEM-based transfusion was associated with lower volume of total blood products transfused (1624.18±1774.79vs. 2810.88±1847.46 mL; p=.02), with medium-to-large effect size (Cohen's d=0.66). This difference was no longer significant after adjustment for TXA (β=−0.18; 95% CI [−1995.78 to 671.64]; p=.32). pRBC and platelet transfusions were comparable between the matched cohorts. The ROTEM group was associated with greater number of cryoprecipitate units (1.24±1.20vs. 0.53±1.01 units; p=.03) and lower FFP (119.76±230.82vs. 673.06±627.08 mL; p CONCLUSIONS Compared to the conventional transfusion criteria, the use of ROTEM-guided transfusion algorithm in lumbar PSO for surgical correction of ASD was associated with greater number of cryoprecipitate units and lower FFP volume transfused. ROTEM-guided transfusion allowed early identification and treatment of hypofibrinogenemia, and aggressive management of this complication may reduce intraoperative EBL and total volume of blood products transfused.

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 CONTEXT Pelvic fixation has a pivotal role in promoting fusion at the lumbosacral junction after instrumented spine surgery. Iliac screws have a long, established history of being utilized for spinopelvic fixation. However, pelvic fixation remains challenging. Recent literature describing complications associated with iliac screw fixation in adult patients has been limited. PURPOSE The purpose of this study was to report our experience with iliac screw fixation in a large series of adult patients with a 2-year minimum follow-up. STUDY DESIGN/SETTING Retrospective review of a prospectively maintained single-institution, multisurgeon database. PATIENT SAMPLE Consecutive patients undergoing spinopelvic fixation with iliac screws. OUTCOME MEASURES Complications and reoperation rates. METHODS A total of 327 adult patients undergoing spinopelvic fixation with iliac screws at our institution between 2010 and 2015, 260 met the study's inclusion criteria (age ≥ 18 years, first-time iliac screw placement, and 2-year minimum clinical and radiographic follow-up). Patients with evidence of active spinal infection were excluded. All iliac screw heads were deeply recessed into the posterior superior iliac spine to avoid prominence. Clinical and radiographic data, including complications, were obtained and then analyzed. Univariate and/or multivariate analyses were used to assess complications. RESULTS A total of 20 patients (7.7%) had iliac screw failure, which included fracture (12, 4.6%) and loosening (9, 3.5%). One patient had both fracture and loosening. No patients had iliac screw head prominence that required revision surgery, caused pain, caused wound dehiscence over the screw head, or produced poor cosmesis. Eleven (4.2%) patients had rod fracture below S1. A total of 23 patients (8.8%) had L5/S1 pseudarthrosis. Of the patients with iliac screw fracture or loosening, solid fusion at L5/S1 was seen in eight (66.7%) and five (55.6%) patients, respectively. All patients with rod fracture below S1 had solid fusion at L5/S1. 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. Our rate of reoperation (excluding revisions for PJK) was 17.7% (46). On univariate analysis, iliac screw failure was significantly associated with revision fusion (70.0% vs. 41.2%, p=.013), greater number of instrumented vertebra (12.6 vs. 10.3, p=.014), and greater postoperative pelvic tilt (27.7 vs. 23.2, p=.04). Lumbosacral junction complication was significantly associated with greater number of instrumented vertebra (12.6 vs. 10.3, p=.014). Reoperation was significantly associated with younger age at surgery (61.8 vs. 65.8, p=.014, greater number of instrumented vertebra (12.2 vs. 10.2, p=.001), and longer clinical and radiographic follow-up (55.8 vs. 44.5, p CONCLUSIONS Previous studies on iliac screw fixation have reported high rates of complications and reoperation, and alternative fixation techniques have been proposed in response. In this large, single-center series of adult patients, iliac screws were an effective method of spinopelvic fixation with high rates of lumbosacral fusion and lower complication rates than previously reported. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.