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Minimally invasive spine surgery (MISS) is increasingly performed using endoscopic and microscopic visualization, and the captured video can be used for surgical education and development of predictive artificial intelligence (AI) models. Video datasets depicting adverse event management are also valuable, as predictive models not exposed to adverse events may exhibit poor performance when these occur. Given that no dedicated spine surgery video datasets for AI model development are publicly available, we introduce Simulated Outcomes for Durotomy Repair in Minimally Invasive Spine Surgery (SOSpine). A validated MISS cadaveric dural repair simulator was used to educate neurosurgery residents, and surgical microscope video recordings were paired with outcome data. Objects including durotomy, needle, grasper, needle driver, and nerve hook were then annotated. Altogether, SOSpine contains 15,698 frames with 53,238 annotations and associated durotomy repair outcomes. For validation, an AI model was fine-tuned on SOSpine video and detected surgical instruments with a mean average precision of 0.77. In summary, SOSpine depicts spine surgeons managing a common complication, providing opportunities to develop surgical AI models. [ABSTRACT FROM AUTHOR]

Study Design: Prospective single-cohort analysis. Objectives: To compare the outcomes/complications of 2 robotic systems for spine surgery. Methods: Adult patients (≥18-years-old) who underwent robot-assisted spine surgery from 2016-2019 were assessed. A propensity score matching (PSM) algorithm was used to match Mazor X to Renaissance cases. Preoperative CT scan for planning and an intraoperative O-arm for screw evaluation were preformed. Outcomes included screw accuracy, robot time/screw, robot abandonment, and radiation. Screw accuracy was measured using Vitrea Core software by 2 orthopedic surgeons. Screw breach was measured according to the Gertzbein/Robbins classification. Results: After PSA, a total of 65 patients (Renaissance: 22 vs. X: 43) were included. Patient/operative factors were similar between robot systems (P >.05). The pedicle screw accuracy was similar between robots (Renaissance: 1.1%% vs. X: 1.3%, P =.786); however, the S2AI screw breach rate was significantly lower for the X (Renaissance: 9.5% vs. X: 1.2%, P =.025). Robot time per screw was not statistically different (Renaissance: 4.6 minutes vs. X: 3.9 minutes, P =.246). The X was more reliable with an abandonment rate of 2.3% vs. Renaissance:22.7%, P =.007. Radiation exposure were not different between robot systems. Non-robot related complications including dural tear, loss of motor/sensory function, and blood transfusion were similar between robot systems. Conclusion: This is the first comparative analyses of screw accuracy, robot time/screw, robot abandonment, and radiation exposure between the Mazor X and Renaissance systems. There are substantial improvements in the X robot, particularly in the perioperative planning processes, which likely contribute to the X's superiority in S2AI screw accuracy by nearly 8-fold and robot reliability by nearly 10-fold. [ABSTRACT FROM AUTHOR]

Objective: Evaluate clinical improvement as measured by patient-reported outcomes (PROs) during the 1 to 2-year interval. Study Design: Retrospective Cohort. Methods: A single-institution registry of ASD patients undergoing surgery was queried for patients with ≥6 level fusions. Demographics and radiographic variables were collected. PROs collected were the ODI and SRS-22r scores at: preoperative, 1-year and 2-years. Outcome measures of clinical improvement during the 1-2 year time interval were: 1) group medians, 2) percent minimum clinically important difference (MCID), and 3) percent minimal symptom scale (MSS)(ODI < 20 or SRS-pain + function >8). Wilcoxon rank-sum tests, chi-squared tests, Kruskal-Wallis tests, and logistic regression were performed. Results: 157 patients undergoing ASD surgery with minimum of 1-year follow-up were included. Mean age was 53.2 and mean instrumented levels was 13.1. Preoperative alignment was: Neutral Alignment (NA) 49%, Coronal Malalignment (CM) 17%, Sagittal Malalignment (SM 17%), and Combined Coronal/Sagittal Malalignment (CCSM) 18%. Preoperative to 1-year, and preoperative to 2-years, all ODI/SRS-22r significantly improved (P <.001). In all patients, the only significant improvement in PROs between 1-and 2-year postoperative were those reaching ODI MCID (69% 1-year vs. 84% 2-years; P <.001). Subgroup analysis: ≥55 years had an improved median ODI (18 vs. 8; P =.047) and an improved percent achieving ODI MCID (73% vs. 84%, P =.048). CCSM patients experienced significant improvement in SRS-appearance score (75% vs. 100%; P =.050), along with those with severe preoperative SM >7.5 cm (73% vs. 100%; P =.032). Conclusions: Most ASD patients experience the majority of PRO improvement by 1-year postoperative. However, subsets of patients that may continue to improve up to 2-years postoperative include patients ≥55 years, combined coronal/sagittal malalignment, and those with severe sagittal malalignment ≥7.5 cm. [ABSTRACT FROM AUTHOR]

In a cohort of elite rowers requiring lumbar spine surgery, we report information regarding: (1) presentation, (2) operative treatment, and (3) return to play (RTP). All competitive rowers undergoing spine surgery at a single academic institution from 2015 to 2020 were analyzed. Three rowers underwent spine surgery during the allotted time period. Demographic, clinical, operative, and RTP data was recorded. Each athlete's self-reported level of effort/performance was assessed before and after surgery. First RTP was defined as the time of initial return to rowing activities, and full RTP was defined as the time of unrestricted return to rowing activities. Descriptive statistics were performed. The three collegiate rowers ranged from 20- to 21-year-old, each with L5/S1 disc herniations. Preoperative pain levels ranged from 8 to 10, and inciting injury events included back squats, front squats, and rowing during the 'finish' stage. Each athlete underwent a minimally invasive, unilateral L5/S1 decompression, partial medial facetectomy, and partial discectomy with microscopic-assistance. First RTP ranged from 4-6 months, with full RTP at 6–8 months. Pain dissipated to the 0–1 range at full RTP. Final effort/performance improved from 10–60% mid-injury to 90–100% at full RTP. Each athlete's 2000m row time showed a decline mid-injury and an improvement to at or within 10 s of their pre-injury time. Drawing from three collegiate rowers who underwent lumbar decompression surgery, each athlete successfully returned to rowing, with initial RTP in the 4–6 months range and full RTP in the 6–8 months range. Performance levels rebounded to near or better than pre-injury performance. The results of this small case series warrant replication in larger, multi-institutional samples. [ABSTRACT FROM AUTHOR]

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 yrs old) who underwent robot-assisted short lumbar fusion surgery from 2015 to 2019 at four independent institutions. A propensity score matching 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 propensity score matching, 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 min) versus the percutaneous group (167 min, 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 s) was longer than the open group (10.1 s, 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 < 0.001) and transfusion rate (open: 3.9% vs. percutaneous: 0%, P value = 0.013) were greater for the open group. The 90-day complication rate and mean length of stay were not different between cohorts (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. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effect of coronal alignment on: (1) surgical invasiveness and operative complexity and (2) postoperative complications. Methods: A retrospective, cohort study of adult spinal deformity patients was conducted. Alignment groups were: (1) neutral alignment (NA): coronal vertical axis (CVA) ≤ 3 cm and sagittal vertical axis (SVA) ≤ 5 cm; (2) coronal malalignment (CM) only: CVA > 3 cm; (3) Sagittal malalignment (SM) only: SVA > 5 cm; and (4) coronal and sagittal malalignment (CCSM): CVA > 3 cm and SVA > 5 cm. Results: Of 243 patients, alignment groups were: NA 115 (47.3%), CM 48 (19.8%), SM 38 (15.6%), and CCSM 42 (17.3%). Total instrumented levels (TILs) were highest in CM (14.5 ± 3.7) and CCSM groups (14 ± 4.0) (p < 0.001). More 3-column osteotomies (3COs) were performed in SM (21.1%) and CCSM (28.9%) groups than CM (10.4%) (p = 0.003). CM patients had more levels instrumented (p = 0.029), posterior column osteotomies (PCOs) (p < 0.001), and TLIFs (p = 0.002) than SM patients. CCSM patients had more TLIFs (p = 0.012) and higher estimated blood loss (EBL) (p = 0.003) than SM patients. CVA displayed a stronger relationship with TIL (p = 0.002), EBL (p < 0.001), and operative time (p < 0.001) than SVA, which had only one significant association with EBL (p = 0.010). Both SM/CCSM patients had higher readmissions (p = 0.003) and reoperations (p < 0.001) than CM patients. Conclusion: Amount of preoperative CM was a better predictor of surgical invasiveness than the amount of SM, despite 3COs more commonly performed in SM patients. CM patients had more instrumented levels, PCOs, and TLIFs than SM patients. [ABSTRACT FROM AUTHOR]

Venous thromboembolism (VTE) is an appreciable burden on health care. The protracted recumbency experienced by many spinal patients juxtaposed with concerns for postoperative hemorrhage from early anticoagulation results in conflicting stances regarding chemoprophylaxis. Identifying risk factors associated with VTE is therefore instrumental in guiding management. To identify VTE risk factors in patients undergoing degenerative spine surgery. The Nationwide Readmissions Database was searched for adults undergoing spine surgery for degenerative diseases between 2010 and 2014. The 30-day and 90-day VTE incidence was estimated from readmissions with new VTE diagnoses. A multivariate survey-adjusted logistic regression model was used to identify variables associated with VTE diagnoses on readmission. Of 838,507 degenerative spine cases queried, 3499 patients (0.42%) were readmitted with a VTE diagnosis within 30 days and 4321 patients (0.62%) were readmitted within 90 days. In multivariate analysis, steroids were independently associated with a higher likelihood of readmission with VTE at both 30 days (odds ratio, 1.58; P < 0.001) and 90 days (odds ratio, 1.97; P < 0.001). Significant associations were also identified with thoracolumbar surgery, length of stay, and discharge to institutional care. The incidence of readmission with VTE diagnoses in spine surgery is low. However, their devastating consequences underscore the need to identify those patients deemed high risk. These patients include those having thoracolumbar surgery, of advanced age, with prolonged length of stay, using corticosteroids, and with a disposition to institutional care (e.g., skilled nursing facility or long-term acute care). Given the association between steroids and VTE, clinicians should be judicious about perioperative administration despite their obvious antiinflammatory benefits. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing interest among spine surgeons in robot-assisted surgery. One of the first FDA-approved robot-assisted systems was the SpineAssist (Mazor Robotics) in 2004. Since that time, Mazor has released next generation systems, such as the Renaissance (2011) and Mazor X (2016). Although robot-assisted spine surgery continues to be extensively studied, there is limited literature on the Mazor X system and no studies have compared the Mazor X and the Renaissance systems. It is important to investigate if recent advances in robotic technology have any clinical significance. To compare the screw accuracy, robot time per screw, robot abandonment, and radiation exposure of two robotic systems for spine surgery. Prospective Single-Cohort Analysis. Adult patients (≥18 years) underwent robot-assisted spine surgery from 2016-2019. Screw accuracy, robot time per screw, robot abandonment, and radiation exposure. Adult (≥18 years old) patients who underwent robot-assisted spine surgery from 2016-2019 were reviewed. A propensity score matching algorithm was used to match Mazor X cases to Renaissance cases to control for potential selection bias. All cases involved a preoperative CT scan for planning and an intraoperative O-arm for screw evaluation. Outcomes of interest included screw accuracy, robot time per screw, robot abandonment and radiation exposure (preoperative and intraoperative). Screw accuracy was measured using Vitrea Core software by two independent orthopedic surgeons. Screw breach was measured according to the Gertzbein and Robbins classification. Bivariate comparisons were performed using chi-square and t-tests. A P-value <0.05 was considered statistically significant. After propensity score matching, a total of 65 patients (Renaissance: 22 vs X: 43) were included. Patient demographics, diagnoses, discharge disposition, and operative factors (eg, number of instrumented levels, pelvic fixation, interbody fusion, planned robot screws per patient) were similar between robot systems (P>0.05). The pedicle screw accuracy was similar between robots (Screw exchange for breach rate: Renaissance: 1.1% vs X: 1.3%, P=0.786); however, the S2AI screw breach rate was significantly lower for the X (Renaissance: 9.5% vs X: 1.2%, P=0.025). The X appeared to have a shorter robot time per screw but this was not statistically significant (Renaissance: 4.6 minutes vs X: 3.9 minutes, P=0.246). The X robot was significantly more reliable with a robot abandonment rate of only 2.3% vs Renaissance: 22.7%, P=0.007. Radiation exposure (dose and time), including preoperative and intraoperative levels were not different between robot systems. Non-robot related complications including dural tear, loss of motor/sensory function, estimated blood loss and blood transfusion were similar between robot systems. This is the first comparative analysis of robot complications, radiation exposure, operative efficacy and outcomes between the Mazor X and Renaissance systems. There are substantial improvements in the X robot, particularly in the perioperative planning processes, which likely contribute to the X's superiority in screw accuracy and robot reliability. Compared to the Renaissance, the Mazor X demonstrated a significantly higher rate of S2AI screw accuracy and a lower rate of robot abandonment due to registration issues. Medtronic Mazor X is FDA approved in the US. [ABSTRACT FROM AUTHOR]

Although there has been a growing amount of literature that suggests robots are safe and can achieve comparable outcomes to conventional techniques, much of this literature is limited by small sample sizes and single-surgeon or single center series. Furthermore, it is unclear what the impact of robotic technology has made on operative and clinical outcomes over time. This is the first and largest multicenter study to examine the trends in outcomes and complications after robot-assisted spine surgery over a 5-year period. To examine trends in outcomes and complications after robot-assisted spine surgery from 2015-2019. Multicenter cohort. Adult (≥18 years old) patients who underwent robot-assisted (Mazor Renaissance, X, and Stealth) spine surgery from 2015 to 2019. Outcomes of interest included operative efficiency (robot time per screw), radiation exposure (fluoroscopy time per screw), robot complications (eg, screw exchange, robot abandonment), clinical outcomes (eg, length of stay, 90-day reoperations), and other nonrobot-related complications (eg, dural tear, loss of motor/sensory function, blood transfusion). In this multicenter study, we included adult (≥18 years old) patients who underwent robot-assisted spine surgery between 2015 and 2019 at four geographically diverse institutions. The robotic systems used included the Mazor Renaissance, Mazor X, and Mazor Stealth Edition. Patients with missing data were excluded from this study. The minimum follow-up was 90 days after the index surgery. This study was approved by the institutional review board. Chi-square/fisher exact test and t-test/ANOVA were used for categorical and continuous variables, respectively. The Cochran-Armitage test was used to examine statistically significant trends. Statistical significance was defined as a P-value <0.05. SAS Studio Version 3.4 (SAS Institute Inc, Cary, NC) was used for all statistical analyses. 722 adult patients were included (117 Renaissance, 477 X, 128 Stealth). Mean (standard deviation) Charlson comorbidity index (CCI) was 1.5 (1.5). The most common diagnoses included high grade spondylolisthesis (grade>2) (40.6%), degenerative disc disease (18.4%), and degenerative scoliosis (17.6%). Mean (standard deviation) number of instrumented levels was 3.8(3.4). Most patient and operative factors (eg, gender, smoking status, total instrumented levels, and pelvic fixation,) were similar across the years. From 2015-2019, mean robot time per screw decreased from 7.2 minutes to 5.5 minutes (P=0.004, R2=0.65). Mean fluoroscopy time per screw decreased from 15.2 seconds to 9.4 seconds (P=0.002, R2=0.83). Rates of both intraoperative screw exchange for misplaced screw (2015-2016: 2.7%, 2019: 0.8%, P=0.0115, R2=0.13) and robot abandonment (2015-2016: 7.1%, 2019: 1.1%, P=0.011, R2=0.22) improved significantly over time. The incidence of other intraoperative nonrobot related complications (eg, dural tear, loss of motor/sensory function, blood transfusion) remained consistently low, but similar between years. The LOS decreased by nearly 1 day from 2015-2019(P=0.007, R2=0.78). 90-day reoperation rates did not change significantly. Current trends demonstrate that robot screw accuracy, reliability, operative efficiency, and radiation exposure have improved significantly over the last five years. This is likely the result of increased surgeon experience with robots and the recent advances in robotic technology. The 90-day surgical complication rates remain consistently low and the mean length of stay has reduced significantly with time, which may offset the cost of robot-assisted spine surgery; however, future work specifically focusing on cost analyses are needed. Nevertheless, these findings further validate the continued usage of robot-assisted spine surgery and the potential path toward improved value-based care. Medtronic Renaissance, Mazor X and Mazor X stealth are FDA approved in the US. [ABSTRACT FROM AUTHOR]

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). To compare the screw accuracy, robot reliability and efficiency, and 1-year clinical outcomes between two robot platforms. Multicenter cohort. 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. Screw accuracy, robot time per screw, robot abandonment, and 1-year clinical outcomes between two robot systems. 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. 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<0.001). The 90-day and 1-year complication rates were low and similar between robot cohorts. 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. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Background Context: 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.Purpose: To compare the outcomes and complications between the most recent iterations of the Mazor Robot systems: Mazor X and Mazor X Stealth Edition.Study Design: 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.Outcome Measures: Primary outcomes included robot time per screw, fluoroscopic radiation time, screw accuracy, robot abandonment, and clinical outcomes with a minimum 90 day follow up.Methods: 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.Results: 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 (p>0.05). 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 (p>0.05). The 90-day complication rates were low and similar between robot cohorts (Stealth: 5.4% vs. X: 3.8%, p=0.456).Conclusion: 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. [ABSTRACT FROM AUTHOR]

Study Design.: Delphi method. Objective.: To gain consensus on the following questions: (1) When should anticoagulation/antiplatelet (AC/AP) medication be stopped before elective spine surgery?; (2) When should AC/AP medication be restarted after elective spine surgery?; (3) When, how, and in whom should venous thromboembolism (VTE) chemoprophylaxis be started after elective spinal surgery? Summary of Background Data.: VTE can lead to significant morbidity after adult spine surgery, yet postoperative VTE prophylaxis practices vary considerably. The management of preoperative AC/AP medication is similarly heterogeneous. Materials and Methods.: Delphi method of consensus development consisting of three rounds (January 26, 2021, to June 21, 2021). Results.: Twenty-one spine surgeons were invited, and 20 surgeons completed all rounds of questioning. Consensus (>70% agreement) was achieved in 26/27 items. Group consensus stated that preoperative Direct Oral Anticoagulants should be stopped two days before surgery, warfarin stopped five days before surgery, and all remaining AC/AP medication and aspirin should be stopped seven days before surgery. For restarting AC/AP medication postoperatively, consensus was achieved for low-risk/medium-risk/high-risk patients in 5/5 risk factors (VTE history/cardiac/ambulation status/anterior approach/operation). The low/medium/high thresholds were POD7/POD5/POD2, respectively. For VTE chemoprophylaxis, consensus was achieved for low-risk/medium-risk/high-risk patients in 12/13 risk factors (age/BMI/VTE history/cardiac/cancer/hormone therapy/operation/anterior approach/staged separate days/staged same days/operative time/transfusion). The one area that did not gain consensus was same-day staged surgery. The low-threshold/medium-threshold/high-threshold ranges were postoperative day 5 (POD5) or none/POD3-4/POD1-2, respectively. Additional VTE chemoprophylaxis considerations that gained consensus were POD1 defined as the morning after surgery regardless of operating finishing time, enoxaparin as the medication of choice, and standardized, rather than weight-based, dose given once per day. Conclusions.: In the first known Delphi study to address anticoagulation/antiplatelet recommendations for elective spine surgery (preoperatively and postoperatively); our Delphi consensus recommendations from 20 spine surgeons achieved consensus on 26/27 items. These results will potentially help standardize the management of preoperative AC/AP medication and VTE chemoprophylaxis after adult elective spine surgery. [ABSTRACT FROM AUTHOR]

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. 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. Multicenter cohort. 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. Primary outcomes included robot time per screw, robot abandonment, screw accuracy, radiation exposure and 90-day reoperation rate. 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. 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<0.001). 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 OR during same admission, and LOS was similar between robots (p>0.05). The 90-day reoperation rates were low and similar between robot cohorts. 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. Medtronic Mazor X and Mazor X stealth are FDA approved in the US. [ABSTRACT FROM AUTHOR]

Proximal junctional kyphosis (PJK) after spine deformity surgery is a radiographic phenomenon defined based on the proximal junctional angle (PJA). Currently, there is minimal literature demonstrating correlation between clinical outcome scores and PJA. The lack of correlation may be due to the inadequate assessment of global spinal alignment from the PJA. The C2PA is a novel radiographic angle that portrays the mismatch between the global spinal alignment and alignment proximal to the spine that corresponds with ODI and SRS scores. The definition of PJK after spine deformity surgery is based on the PJA. Despite the growing amount of literature on PJK, minimal correlation exists between PJK and clinical outcome scores. PJA poorly represents, and is difficult to measure, PJK for global spinal alignment after deformity surgery. C2PA is a novel radiographic angle that demonstrates the difference between global spinal alignment and alignment proximal to the spinal construct. Prospectively collected cohort. A radiographic review was performed on 98 deformity patients from July 2015-July 2018. Logistic regression and Chi-square analyses were performed to study the relationship between the postop PJA and C2PA with ODI/SRS scores. A radiographic review was performed on 98 deformity patients from July 2015-July 2018. The angle between the posterior superior sacrum, C2 centroid and upper instrumented vertebrae (UIV) centroid in the pre- and postop setting (2-year or prior to return to OR) were measured and labeled as C2PA. The patients were divided into PJK and non-PJK groups based on (a) PJK defined as PJA >20° and (b) PJK defined as C2PA >20°. Logistic regression and Chi-square analyses were performed to study the relationship between the postop PJA and C2PA with ODI/SRS scores. Of the 98 patients, there were 20 patients with PJK when it was defined as PJA >20°. There was no statistically significant correlation between ODI and SRS scores in the non-PJK and PJK group when it was defined as PJA. There were minimal differences between the ODI scores (8.0 vs 7.0, p=0.66) and the SRS total scores (71.3 vs 70.6, p=0.85) in the Non-PJK and PJK group when it was defined as PJA >20°. When PJK was defined as C2PA >20°, there were 31 patients with PJK. There were statistically significant differences between the non-PJK and PJK group for both ODI (8.0 vs 16.0, p=0.015) and SRS total scores (97.0 vs 88.0, p=0.010) when PJK was defined as C2PA >20° This is the first study demonstrating that C2PA is a superior radiographic representation of PJK, and directly correlates with patient-reported outcomes. C2PA >20° is the critical angle that corresponds with clinical PJK. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Little is known regarding the incidence and risk factors for postop CM after ASD surgery. A subset of patients undergoing adult spinal deformity (ASD) surgery will have postoperative coronal malalignment (CM) with suboptimal outcomes. Retrospective cohort. A total of 243 adult spinal deformity patients. Postoperative Coronal Malalignment. A single-institution database was queried for ASD patients undergoing ≥6 level fusions from 2015-19. Postop coronal malalignment was defined as C7 coronal vertical axis (CVA) >3cm. Iatrogenic coronal malalignment was defined as postop CVA>3cm in patients without preop CM. Demographic, radiographic, and surgical variables were collected. 2-year outcomes included: complications, readmissions, reoperations, and aODI/SRS-22r. Logistic regression was performed. A total of 243 ASD patients had preop and immediate postop measurements; 174 patients (72%) had 2-year follow-up. Mean age was 50.9±17.6 & mean instrumented levels was 13.5±3.9. Mean preop CVA was 2.9±2.7cm, and 90 (37%) had preop CM. Postop CM was seen in 43 (18%) patients, 13 (5%) of which were iatrogenic. Significant risk factors for postop CM were: EBL (OR 1.00, p=0.026), operative time (OR 1.16, p=0.045), preop CVA (OR 1.21, p=0.001), preop SVA (OR 1.05, p=0.046), pelvic obliquity (angle between horizontal & iliac crests) (OR 1.21, p=0.008), lumbosacral fractional (LSF) curve concavity to the same side as the CVA (OR 2.31, p=0.043), & max cobb angle concavity opposite the CVA (OR 2.10, p=0.033). The single significant risk factor for iatrogenic postoperative CM was a LSF curve concavity to the same side as the CVA (OR 11.39, p=0.020). Patients with postop CM were more likely to sustain a postop complication (31.0% vs 14.3%, p=0.009), yet no differences were seen in readmissions (p=0.743) or reoperations (p=1.000). No significant differences were seen in 2-year PROs according to postop coronal malalignment. Postoperative coronal malalignment occurred in 18% of adult spinal deformity patients and was most associated with preoperative CVA, pelvic obliquity, LSF curve to the same side as the CVA, and max cobb angle to the opposite side of the CVA. Though postoperative coronal malalignment was significantly associated with increased complications, surprisingly, readmission, reoperation, & 2-year PROs were similar in those with and without coronal malalignment. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

No radiographic alignment threshold defines preop CM in ASD patients based on disability. An optimal threshold exists that defines CM based on patient-reported outcomes (PROs) in ASD patients. Cross-sectional. This study included 368 adult deformity patients. Patient-reported outcomes (ODI and SRS22r) and postoperative coronal and sagittal alignment A single-institution registry was searched for all patients undergoing ASD surgery with ≥6 level fusions. Coronal vertical axis (CVA) & sagittal vertical axis (SVA) were collected. PROs were preop ODI/SRS-22r scores. First, CVA & SVA thresholds were derived to accurately differentiate patients with ODI>40 & SRS-pain+function scores<6. Second, patients were separated and compared based on 4 groups: (1) neutral alignment (NA); 2) coronal malalignment only (CM); (3) sagittal malalignment only (SM); (4) combined coronal & sagittal malalignment (CCSM). Chi-square, Kruskal-Wallis, & linear regression were performed. A total of 368 patients underwent ASD surgery with a mean CVA of 3.1±4.1cm. Part 1: thresholds to distinguish patients with ODI>40 and SRS-pain/fx <6 were: (1) CVA=3.96cm (ODI) and 3.17cm (SRS) and (2) SVA=4.97cm (ODI) and 7.52cm (SRS). To stay conservative, the lower numbers were chosen to define each threshold: CVA=3cm; SVA=5cm. Part 2: alignment breakdown was: NA 179 (48.6%), CM 66 (17.9%), SM 65 (17.7%), & CCSM 58 (15.8%). Based on preop ODI scores, both SM (p=0.006) & CCSM (p<0.001) patients were significantly worse than NA patients. CCSM patients were significantly worse than SM alone (p=0.010). Based on preop total SRS-22r scores, only CCSM (p=0.003) patients were significantly worse than the NA group. CVA significantly correlated with 4/7 (57%) PROs (ODI/SRS-total/function/image), while SVA correlated with 5/7 (71%) PROs (ODI/SRS-total/function/image/pain). A linear relationship was seen between increasing CVA & worsening ODI (β=0.92, p=0.001). A significant yet slightly stronger relationship was seen between increasing SVA & worsening ODI (β=1.28, p<0.001). Alignment thresholds that accurately distinguished ASD patients with severe pain and disability preoperatively were 3cm for CVA and 5cm for SVA. Preop CM was significantly associated with worse ODI, SRS-22r total/function/image scores. CCSM lead to more disability than SM alone. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Conventional adult spinal deformity (ASD) measurements evaluate coronal alignment from C7-sacrum. Little is known about coronal alignment from the skull. Assess coronal alignment evaluated from the skull and correlations with preoperative/postoperative measurements and function. Retrospective cohort. Adult spinal deformity patients from a multi-surgeon single-institution database. Patient-reported outcomes and postoperative radiographic parameters. A single-institution, ASD database was searched for adult spinal deformity patients with at least six or more levels fused. Traditional C7-coronal vertical axis (C7-CVA) measurements were obtained, as was the orbital-CVA (ORB-CVA): the distance between the sacral plumb line and a vertical line from the mid-point between medial orbital walls. The ORB-CVA was correlated with traditional coronal measurements, including C7-CVA, maximum coronal cobb angle, pelvic obliquity (PO), & leg length discrepancy (LLD). Coronal malalignment (CM) was defined as C7-CVA >3cm. Measures of clinical improvement were: (1) group PRO means, (2) minimum clinically important difference (MCID) and (3) minimal symptom scale (MSS) (ODI<20 or SRS-pain+fx>8). A total of 243 patients underwent ASD surgery, and 175 had 2-year follow-up. Ninety (37%) patients had preop CM while mean (range) ORB-CVA at each time point was: preoperative 2.9±3.1 (-14.2-25.6), 1-year postoperative 2.0±1.6 (-12.4-6.7), 2-year postoperative 1.8±1.7 (-6.0, 11.1) (p<0.001 from preoperative to 1-year and 2-year). Preoperative ORB-CVA correlated best with CVA (r=0.842, p<0.001), max coronal Cobb (r=0.166, p=0.010), PO (r=0.293, p<0.001), and LLD (r=0.158, p=0.006). Postoperative, ORB-CVA correlated only with CVA (r=0.627, p<0.001) & LLD (r=0.160, p=0.013). Of the total, 155 (63.2%) patients had an ORB-CVA that was ≥5mm different than C7-CVA. Women were more likely than men to have an ORB-CVA closer to midline than C7-CVA (69% vs 45%, p=0.004). ORB-CVA correlated as well and sometimes better than C7-CVA in SRS-22r subdomains. The ORB-CVA slightly outperformed C7-CVA in its ability to capture patients achieving MCID for SRS-appearance (AUC=0.664 vs 0.513) and with MSS (AUC 0.609 vs AUC 0.542). The ORB-CVA correlated well with known coronal measurements and PROs. Sixty-three percent of patients had an ORB-CVA >5mm different than the C7-CVA, and women were more likely than men to have an ORB-CVA closer to midline than the C7-CVA, indicating a potential compensatory ability. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Proximal junctional kyphosis (PJK) after spine deformity surgery is a frequent complication with multiple etiologies ranging from patient factors to surgical techniques. The paraspinal musculature at the upper instrumented vertebrae (UIV) is an understudied potential risk factor for PJK. This study classifies the paraspinal fat atrophy at the UIV into 3 different grades and correlates with postoperative sagittal alignment and PJK. The paraspinal musculature quality at the UIV is an understudied risk factor for PJK. We propose an easily distinguishable classification to categorize the different grades of preoperative paraspinal fat atrophy and correlate that with postoperative radiographic outcomes. Prospectively collected cohort. A radiographic review was performed on 116 deformity patients from 2015-2018. Logistic regression and Chi-square analyses were performed to study the relationship between the different UIV paraspinal muscle fat atrophy grades and postoperative sagittal balance. A radiographic review was performed on 116 deformity patients from 2015-2018. The paraspinal muscle at the UIV was assessed using the preoperative axial MRI. Grade 1 was defined as fatty infiltrate between 0-10%, grade 2 between 10%-50%, and grade 3 over 50%. Preop, immediate postop and 2-year postop spine films were assessed. PJK was defined as PJA >15°. Logistic regression and Chi-square analyses were performed to study the relationship between the different UIV paraspinal muscle fat atrophy grades and postoperative sagittal balance. Of the 116 patients, 74 had grade 1, 34 had grade 2, and 8 had grade 3 paraspinal fat atrophy. The immediate postop T1PA for grade 1, 2, and 3 were 11.85, 14.8, and 17.7°. The 2-year postop T1PA for grade 1, 2, and 3 were 9.5, 16.9, and 19.6°. The immediate postop PJA for grade 1, 2, and 3 were 8.1, 8.7, and 15.0°. The 2-year postop PJA for grade 1, 2, and 3 were 7.7, 16.9, and 25.2°. For patients in the grade 1 cohort, 7 had PJK immediate postop and 14 had PJK at 2-year postop. Grade 2 cohort had 7 immediate postop PJK patients and 20 at 2-year postop. Grade 3 cohort had 4 immediate postop PJK patients and 7 at 2-year postop. The odds ratio of developing PJK for grade 2 fat atrophy was 6.1 and for grade 3 was 30.0. Higher grades of preoperative paraspinal fat atrophy in the UIV musculature in spine deformity cases is a risk factor for PJK, with the odds ratio of developing PJK for grade 2 fat atrophy at 6.1 and for grade 3 an astounding 30.0. Also, there is greater progression of sagittal malalignment with higher paraspinal fat atrophy grades. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

We established the first intraoperative parameter that directly correlates with postoperative proximal junctional kyphosis (PJK). C2 pelvic angle (C2PA) is a novel, intraoperative radiographic parameter used to assess for potential development of PJK. Intraoperative C2PA >15° is a critical angle with 2.5 times the relative risk for developing PJK. No patient with intraoperative C2PA <15° developed PJK. PJK is a postoperative complication of adult spinal deformity surgery that leads to poorer patient clinical outcomes. There is no literature on intraoperative assessment of sagittal alignment to prevent PJK. Intraoperative C2PA is a novel, radiographic parameter derived from the difference between global spinal alignment and the alignment proximal to the uninstrumented spine. The goal of this study is to demonstrate a positive relationship between the intraoperative C2PA and PJK. Prospectively collected cohorts. Sixty deformity patients from 2015- 2018 who had preop, intraop, immediate postop and 2-year postop full length spine films. Logistic regression and Chi-square analyses evaluated the relationship between the postop PJA and intraop C2PA/PJA. We performed radiographic analysis on 60 deformity patients from 2015- 2018. Of the 60 patients, 35 were fused to the sacrum/pelvis. C2PA is defined as the angle between the posterior superior sacrum, C2 centroid and upper instrumented vertebrae (UIV) centroid and measured in the pre-, intra-, and postop setting (immediate and 2 years or prior to return to OR). PJK was defined as postop PJA >15°. Logistic regression and Chi-square analyses evaluated the relationship between the postop PJA and intraop C2PA/PJA. Of the 60 patients, 20 had PJK at the 2-year postop X-ray or prior to return to OR films. The intraop C2PA for the non-PJK and PJK group were 12.5° and 21.2°, respectively (p < 0.0001). The intraop PJA for the non-PJK and PJK group were 5.6° and 7.4°, respectively (p=0.04). The relative risk ratio of developing PJK for patients with intraop C2PA >15° was 2.43, and no one with intraop C2PA <15° developed PJK in the 2-year follow-up. This is the first intraoperative measurement that demonstrates a direct correlation with PJK. Intraoperative C2PA >15° is a critical angle with 2.5 times the relative risk for developing PJK. No patient with intraoperative C2PA <15° developed PJK. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

The lumbosacral fractional curve is often more challenging to correct vs the thoracolumbar/lumbar (TL/L) curve during adult spinal deformity (ASD) surgery, with implications for postoperative coronal alignment. In patients undergoing ASD surgery, the lumbosacral fractional (LSF) curve significantly impacts preop & postop coronal malalignment (CM). Retrospective cohort A total of 243 adult spine deformity patients. Postoperative lumbosacral fractional and maximum Cobb curve correction, coronal vertical axis. Patients undergoing ≥6 level ASD surgery at a single-institution were collected. The LSF curve was the Cobb angle between the sacrum & most tilted lower lumbar vertebra. Coronal vertical axis (CVA) from C7-mid sacrum (cm) was collected. Patients were grouped by alignment: 1) Neutral alignment (N): CVA≤3cm & SVA≤5cm, 2) Coronal malalignment only (CM): CVA>3cm, 3) Sagittal malalignment only (SM): SVA>5cm, or 4) Coronal and sagittal malalignment (CCSM): both CVA>3cm & SVA>5cm. A total of 243 patients underwent ASD surgery: N 115 (47.3%), CM 48 (19.8%), SM 38 (15.6%), CCSM 42 (17.6%). Mean LSF curve was 12.1±9.9° (0.2-62.3). An LSF curve >5° was seen in 174 (71.6%) of all patients & 81.1% of patients with preoperative CM (p=0.012). Largest LSF curves were seen in the CM (14.6±11.9°) & CCSM (13.1±8.3°) groups. 83% of patients had the LSF curve opposite the max Cobb angle. A significant linear relationship was seen between preop LSF curve & preoperative CVA (β =0.03, p=0.042). Immediately postoperative, a linear relationship was seen between CVA and the postop LSF curve (r=0.147, p=0.022), as well as CVA & max Cobb angle (r=0.148, p=0.021), indicating that postoperative coronal alignment is correlated to how much each curve is corrected. Max coronal Cobb angle achieved more % correction than LSF curve (54.5% Cobb vs 46.5% LSF, p=0.025). Postop CM was significantly associated with both the LSF curve to the same side as the CVA (OR 2.3, 95%CI 1.14-4.68, p=0.021) and the max coronal Cobb opposite the CVA (OR 2.1, 95%CI 1.1-4.2, p=0.033), with LSF curve directionality being the stronger predictor. A lumbosacral fractional curve >5° was seen in 81% of adult spinal deformity patients with preoperative coronal malalignment. The lumbosacral fractional curve opposed the max Cobb angle in 83% of cases. The lumbosacral fractional curve was a slightly stronger driver of postop CM than max Cobb angle, potentially due to it being corrected less or not included in the surgery as compared to the max Cobb angle. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]

Achieving optimal coronal alignment can be a formidable challenge in adult spinal deformity surgery, and how pelvic obliquity and leg length discrepancy relate to coronal malalignment remains poorly studied. Pelvic obliquity (PO) and leg length discrepancy (LLD) are associated with preoperative and postoperative coronal malalignment (CM) in surgical adult spinal deformity (ASD) patients. Retrospective cohort. A total of 237 patients undergoing ASD surgery at a single institution. Pelvic obliquity, leg-length discrepancy, coronal malalignment. Patients undergoing ASD surgery (≥6 level fusions) were reviewed from a single-institution. Variables were:1) Pelvic obliquity (PO): angle between horizontal plane and a line touching bilateral iliac crests; 2) Leg-length discrepancy (LLD): distance from femoral head to the tibial plafond. Coronal vertical axis (CVA) and sagittal vertical axis (SVA) were collected, both measured from C7. Coronal malalignment (CM)= CVA >3cm. Oswestry Disability Index (ODI) was collected at preoperative and 2-years postoperative. Of 237 patients undergoing ASD surgery, 90 (37.0%) had preoperative CM. Patients with preoperative CM had a higher PO (2.8±3.2 vs 2.0±1.7, p=0.013), higher percent of patients with PO>3° (35.6% vs 23.5%, p=0.044), and higher percent of patients with LLD>1 cm (21.1% vs 9.8%, p=0.014). While preoperative PO was significantly correlated with CVA (r=0.26, p<0.001) and max Cobb angle (r=0.30, p<0.001), preoperative LLD was only correlated with CVA (r=0.14, p=0.035). 12.2% of CM patients had both clinically significant PO and LLD. Postoperatively, preop PO was significantly associated with both postoperative CM (OR=1.22, 95%CI, p=0.008) and postoperative CVA (β=0.11, p<0.001). A higher preop PO was independently associated with postop complications after multivariate logistic regression (OR=1.24, p=0.010); however, 2-year ODI scores were not. Preoperative LLD had no significant relationship to postop CM, CVA, ODI or complications. Clinically significant pelvic obliquity ≥3° or leg-length discrepancy ≥1 cm was seen in 44.1% of patients with preoperative coronal malalignment, but also 23.5% of patients with normal coronal alignment. Preoperative pelvic obliquity was significantly associated with preoperative coronal vertical axis and max Cobb angle, while preoperative leg-length discrepancy was only associated with preoperative coronal vertical axis. The direction of pelvic obliquity and leg-length discrepancy showed no consistent pattern with coronal vertical axis. Preoperative pelvic obliquity was independently associated with complications but not 2-year ODI scores. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]