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OBJECTIVE Lumbosacral fractional curves in adult spinal deformity (ASD) patients often have sharp coronal curves resulting in significant pain and imbalance. Postoperative stretch neuropraxia after fractional curve correction can lead to discomfort and unsatisfactory outcomes. The goal of this study was to use radiographic measures to increase understanding of the relationship between postoperative stretch neuropraxia and fractional curve correction. METHODS In 62 ASD patients treated from 2015 to 2018, radiographic review was performed, including measurement of the distance between the lower lumbar neural foramen (L4 and L5) in the concavity and convexity of the lumbosacral fractional curve and the ipsilateral femoral heads (FHs; L4–FH and L5–FH) in pre- and postoperative anteroposterior spine radiographs. The largest absolute preoperative to postoperative change in distance between the lower lumbar neural foramen and the ipsilateral FH (ΔL4/L5–FH) was used for analysis. Chi-square analyses, independent and paired t-tests, and logistic regression were performed to study the relationship between L4/L5–FH and stretch neuropraxia for categorical and continuous variables, respectively. RESULTS Of the 62 patients, 13 (21.0%) had postoperative stretch neuropraxia. Patients without postoperative stretch neuropraxia had an average ΔL4–FH distance of 16.2 mm compared to patients with stretch neuropraxia, who had an average ΔL4–FH distance of 31.5 mm (p < 0.01). Patients without postoperative neuropraxia had an average ΔL5–FH distance of 11.1 mm compared to those with stretch neuropraxia, who had an average ΔL5–FH distance of 23.0 mm (p < 0.01). Chi-square analysis showed that patients had a 4.78-fold risk of developing stretch neuropraxia with ΔL4–FH > 20 mm (95% CI 1.3–17.3) and a 5.17-fold risk of developing stretch neuropraxia with ΔL5–FH > 15 mm (95% CI 1.4–18.7). Logistic regression analysis indicated that the odds of developing stretch neuropraxia were 15:1 with a ΔL4–FH > 20 mm (95% CI 3–78) and 21:1 with a ΔL5–FH > 15 mm (95% CI 4–113). CONCLUSIONS The novel ΔL4/L5–FH distances are strongly associated with postoperative stretch neuropraxia in ASD patients. A ΔL4–FH > 20 mm and ΔL5–FH > 15 mm significantly increase the odds for patients to develop postoperative stretch neuropraxia.

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

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.

BACKGROUND: Few studies directly compare the effect of interbody cages with different degrees of lordosis in producing segmental lumbar lordosis (SLL) in the transforaminal lumbar interbody fusion (TLIF) procedure. Thus, we aimed to investigate changes in SLL in hyperlordotic cages compared to standard lordotic cages in open TLIF procedures. METHODS: Thirty-eight consecutive patients who received open TLIF procedures performed by a single surgeon between 2017 and 2018 were reviewed. Twenty patients had “hyperlordotic cages” (20° lordosis), while 18 patients had “standard lordotic cages” (6° lordosis). Twenty-three patients had one-level TLIF procedures and 15 had two-level TLIF. Standard radiographic measurements, including SLL were assessed preoperatively, postoperatively, and at 1-year follow-up. SLL was measured from the superior endplate of the cephalad vertebra to the inferior endplate of the caudal vertebra. Changes in SLL were compared using Student’s and paired t-tests. RESULTS: In one- and two-level open TLIF, both hyperlordotic and standard lordotic cages produced significant improvement in SLL. Among those receiving a one-level TLIF, SLL increased 7.8° (P=0.024) in those with standard lordotic cages; it increased 8.2° (P=0.020) in those with hyperlordotic cages. Among those receiving a two-level TLIF, SLL increased 13.9° (P=0.032) in those with standard lordotic cages; it increased 8.8° (P=0.023) in those with hyperlordotic cages. However, the improvement in SLL was not significantly different between the two cage types in either one or two-level TLIF procedures (P=0.917, P=0.389). At 1-year follow-up, there was no significant change in SLL, among standard lordotic and hyperlordotic cages (P=0.501, P=0.781). CONCLUSIONS: Although it is theorized that hyperlordotic cages would increase SLL during open TLIF procedures more than standard lordotic cages, our data failed to demonstrate that. As our study examined cases performed by a single surgeon immediately before and after adoption of these lordotic cages, it is likely that surgical technique is of equal or greater importance in improving SLL than the amount of lordosis designed into interbody cages.

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.

Purpose To evaluate whether the presence of residents in hip arthroscopy (HA) procedures affects short-term surgical outcomes. Methods The American College of Surgeons National Surgical Quality Improvement Program Database was used to identify patients who underwent HA from 2006 to 2012. Demographic and 30-day outcome variables were compared between cohorts of patients with and without residents. Multivariate logistic regression was used to identify whether resident involvement was an independent risk factor for adverse outcomes. Propensity score matching was performed to control for all demographic and intraoperative variables. Results A total of 869 patients (59.7% female) were included in this study, 626 of which reported data on resident involvement. Patients were mostly White (73.4% of cases without a resident, 51.8% with a resident, P < .05). Those with residents were younger (P = .016), had lower modified 5-item frailty index (mFI-5) scores (P = .028), and had fewer cardiac comorbidities (P = .008). There was no difference in diabetic status, dyspnea symptoms, history of chronic obstructive pulmonary disease, renal comorbidity, neurologic comorbidity, cumulative comorbidities, history of bleeding disorders, inpatient vs. outpatient treatment, preoperative functional status, smoking history, and steroid use for chronic conditions. There was no difference in all complications, operative time, length of stay, reoperation, readmission, wound complication, venous thromboembolism, blood transfusions, or sepsis. Propensity score match for demographic and intraoperative differences found no association between resident involvement and increased complications. Resident involvement was not an independent risk factor for all complications studied. Conclusion Resident involvement in HA procedures was not a risk factor for 30-day complications between 2006 and 2012. Resident involvement did not increase the risk of adverse outcomes, readmission, reoperation, or length of stay, nor did it significantly increase operative times.

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

Unplanned readmissions and reoperations are known to be associated with undesirable costs and potentially inferior outcomes in complex adult spinal deformity (ASD) surgery. A paucity of literature exists on the impact of readmissions/reoperations on patient-reported outcomes (PRO) in this population. Consecutively treated adult patients who underwent complex ASD surgery at a single institution from 2015–2018 and minimum 2-year follow-up were studied. Demographics/comorbidities, operative factors, inpatient complications, and postoperative clinical and patient-reported outcomes (SRS-22r, ODI) were assessed for those with and without readmission/reoperation. 175 patients (72% female, mean age 52.6 ± 16.4) were included. Mean total instrumented/fused levels was 13.3 ± 4.1, range 6–25. The readmission and reoperation rates were 16.6% and 12%, respectively. The two most common causes of reoperation were pseudarthrosis (5.1%) and PJK (4.0%). Predictors for readmission within 2 years following surgery included pulmonary, cardiac, depression and gastrointestinal comorbidities, along with performance of a VCR, and TLIF. At 2 years postoperatively, those who required a readmission/reoperation had significant increases in SRS and reductions in ODI compared to 1-year and preoperative values. Inpatient complications did not negatively impact 2-year PRO’s. The 2-year MCID in PROs was not significantly different between those with and without readmission/reoperation. Complex ASD surgery carries risk, but the vast majority can achieve MCID (SRS-86.4%, ODI-68.2%) in PROs by 2 years. Importantly, even those with inpatient complications and those who required unplanned readmission/reoperation can improve PROs by 2-year follow-up compared to preoperative baseline and 1-year follow-up and achieve similar improvements compared to those who did not require a readmission. III.

Generally, a combined anterior and posterior cervical approach is associated with significant morbidity since it requires an extended operative time, greater intraoperative blood loss, and both anterior- and posterior-related surgical complications. However, there are some instances where a circumferential cervical fusion can be advantageous. Our objective is to discuss the indications for circumferential cervical spine procedures. A narrative review of the literature was performed. We include the indications for circumferential cervical approaches of the senior author (KDR). Indications for circumferential approaches include: (1) high-risk patients for pseudoarthrosis, (2) cervical deformity (e.g. , degenerative, posttraumatic, cervicothoracic kyphosis), (3) cervical spine metastases (especially those with multilevel involvement), (4) cervical spine infection, (5) unstable cervical trauma, (6) movement disorders and cerebral palsy, (7) Multiply operated patient (especially postlaminectomy kyphosis and patients with massive ossification of the posterior longitudinal ligament), and when (8) early fusion is desirable. Circumferential procedures may be useful in many different cervical spine conditions requiring surgery. Despite its advantages, particularly with reducing the risk for pseudarthrosis, the benefits of a combined approach must be weighed against the risks associated with a dual approach. With appropriate preoperative planning, intraoperative decision-making, and surgical techniques, excellent clinical outcomes can be achieved.

Objective To perform a systematic literature review on revision surgeries at the index level after cervical disc arthroplasty (CDA) failure. Methods A systematic literature review was performed according to the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Prospective studies on patients who required a secondary surgery after CDA failure were included for analysis. The minimum follow-up for these studies was 5 years. Results Out of 864 studies in the original search group, a total of 20 studies were included. From a total of 4,087 patients, 161 patients required a reoperation at the index level. A total of 170 surgeries were performed, as some patients required multiple surgeries. The most common secondary procedures were anterior cervical discectomy and fusion (ACDF) (68%, N = 61) and posterior cervical fusion (15.5%, N = 14), followed by other reoperation (13.3%, N = 12). The associated outcomes for those who required a revision surgery were rarely mentioned in the included literature. Conclusion The long-term revision rate at the index level of failed CDA surgery was 3.9%, with a minimum 5-year follow-up. ACDF was the most commonly performed procedure to salvage a failed CDA. Some patients who required a new surgery after CDA failure may require a more extensive salvage procedure and even subsequent surgeries.

Coronal malalignment in adult spinal deformity (ASD) has a close relationship with patient clinical outcomes. The purpose of this study is to evaluate the relationship between intra- and postoperative coronal radiographic parameters. A novel parameter, the central sacral pelvic line (CSPL), and its relation to the central sacral vertical line (CSVL) is explored. CSPL is a measure of spinal alignment referenced to the patient’s pelvis as an intraoperative proxy for CSVL. CSVL is difficult to measure intraoperatively, because a C7-plumb line (referenced to gravity) cannot be drawn in the supine position. 47 subjects ≥ 18 years old undergoing a spinal fusion of ≥ 6 levels from 2015 to 2017 were enrolled. The CSPL is defined as the perpendicular line bisecting the midpoint of the line that connects the superior aspects of the acetabuli. Two metrics describing coronal alignment were derived from each radiograph: (1) horizontal distance between the C7-plumb line and the CSPL at C7 (C7-CSPL) and (2) horizontal distance between the C7-plumb line and CSVL (C7-CSVL). Pearson’s correlation and linear regression analysis was used to study the relationship between the intraoperative C7-CSPL and the postoperative C7-CSVL. On average, the intraoperative C7-CSPL distance was 32.1 mm, postoperative C7-CSPL 20.8 mm, and postoperative C7-CSVL 18.9 mm. 15/47 (32%) had intraoperative C7-CSPL measurements > 4 cm, requiring intraoperative correction. Of those 15, 10 patients (67%) still had a postoperative C7-CSVL 5 cm had a 50% chance of having a postoperative C7-CSVL > 4 cm; patients with intraoperative C7-CSPL

OBJECTIVEWith the continued evolution of bundled payment plans, there has been a greater focus within orthopedic surgery on quality metrics up to 90 days of care. Although the Centers for Medicare and Medicaid Services does not currently penalize hospitals based on their pediatric readmission rates, it is important to understand the drivers for unplanned readmission to improve the quality of care and reduce costs.METHODSThe National Readmission Database provides a nationally representative sample of all discharges from US hospitals and allows follow-up across hospitals up to 1 calendar year. Adolescents (age 10–18 years) who underwent idiopathic scoliosis surgery from 2012 to 2015 were included. Patients were separated into those with and those without readmission within 30 days or between 31 and 90 days. Demographics, operative conditions, hospital factors, and surgical outcomes were compared using the chi-square test and t-test. Independent predictors for readmissions were identified using stepwise multivariate logistic regression.RESULTSA total of 30,677 patients underwent adolescent idiopathic scoliosis surgery from 2012 to 2015. The rates of 30- and 90-day readmissions were 2.9% and 1.4%, respectively. The mean costs associated with the index admission and 30- and 90-day readmissions were $60,680, $23,567, and $16,916, respectively. Common risk factors for readmissions included length of stay > 5 days, obesity, neurological disorders, and chronic use of antiplatelets or anticoagulants. The index admission complications associated with readmissions were unintended durotomy, syndrome of inappropriate antidiuretic hormone, and superior mesenteric artery syndrome. Hospital factors, discharge disposition, and operative conditions appeared to be less important for readmission risk. The top reasons for 30-day and 90-day readmissions were wound infection (34.7%) and implant complications (17.3%), respectively. Readmissions requiring a reoperation were significantly higher for those that occurred between 31 and 90 days after the index readmission.CONCLUSIONSReadmission rates were low for both 30- and 90-day readmissions for adolescent idiopathic scoliosis surgery patients. Nevertheless, readmissions are costly and appear to be associated with potentially modifiable risk factors, although some risk factors remain potentially unavoidable.

BACKGROUND CONTEXT The safety of outpatient one- and two-level anterior cervical discectomy and fusion (ACDF) has been validated in a number of recent studies. However, recent advancements in anesthetic and surgical technique have rendered procedures previously only performed in an inpatient setting, such as three- and four-level ACDF, potentially amenable to outpatient management. PURPOSE The present study aimed to investigate the safety of outpatient three- and four-level ACDF. STUDY DESIGN Retrospective cohort study PATIENT SAMPLE The National Surgical Quality Improvement Program – a large, prospectively-collected registry – was queried to identify patients undergoing three- and four-level ACDF in an inpatient and outpatient setting. OUTCOME MEASURES The rates of total complications, perioperative blood transfusion, and unplanned hospital readmission in three- and four-level ACDF by inpatient or outpatient surgery status. METHODS Baseline patient characteristics and 30-day outcomes were tabulated and compared by inpatient or outpatient status using bivariate analysis. A multivariate analysis was also employed to adjust for differences in baseline patient characteristics when comparing outcomes, and was also used to identify independent predictors of complications and readmissions in patients undergoing three- and four-level ACDF. RESULTS In total 3,441 patients underwent three- or four-level ACDF, with 2,718 (79.0%) procedures occurring inpatient and 723 (21.0%) outpatient. Of patients undergoing outpatient ACDF, 596 patients (82.4%) underwent a three-level and 127 patients (17.6%) underwent four-level procedures. There was an increase in the utilization of outpatient procedures, increasing from 7.0% to 32.9% between 2011 and 2018. Patients undergoing outpatient surgery were younger, white, more likely to have three-level fusions (vs four-level), had a lower American Society of Anesthesiologists (ASA) classification, and were less likely to have a history of diabetes mellitus or dependent functional status. Among the inpatient and outpatient cohorts, there was no significant difference in the rates of total complications (4.49% vs 2.49%) or unplanned readmissions (4.96% vs 3.72%). Increasing age, operative duration, and ASA classification were independent predictors of complications and readmissions, however, inpatient or outpatient surgery status and number of levels fused was not. CONCLUSIONS This present study represents one of the largest cohorts of patients undergoing outpatient three- and four-level ACDF. Outpatient multilevel ACDF is performed in younger and healthier patients, with three-level procedures more commonly the four-level. There was no observed increased rates of total complications or readmissions in patients undergoing outpatient relative to inpatient surgery, however, we did identify increased age, operative duration, and ASA classification as independent predictors of these complications. Patient selection for outpatient procedures is of the highest importance, and future studies developing reproducible selection criteria are warranted.

Study design: Retrospective cohort study. Objective: Respiratory compromise (RC) is a rare but catastrophic complication of anterior cervical spine surgery (ACSS) commonly due to compressive fluid collections or generalized soft tissue swelling in the cervical spine. Established risk factors include operative duration, size of surgical exposure, myelopathy, among others. The purpose of this current study is to identify the incidence and clinical course of patients who develop RC, and identify independent predictors of RC in patients undergoing ACSS for cervical spondylosis. Methods: A large, prospectively-collected registry was used to identify patients undergoing ACSS for spondylosis. Patients with posterior cervical procedures were excluded. Baseline patient characteristics were compared using bivariate analysis, and multivariate analysis was employed to compare postoperative complications and identify independent predictors of RC. Results: 298 of 52,270 patients developed RC (incidence 0.57%). Patients who developed RC had high rates of 30-day mortality (11.7%) and morbidity (75.8%), with unplanned reoperation and pneumonia the most common. The most common reason for reoperations were hematoma evacuation and tracheostomy. Independent patient-specific factors predictive of RC included increasing patient age, male gender, comorbidities such as chronic cardiac and respiratory disease, preoperative myelopathy, prolonged operative duration, and 2-level ACCFs. Conclusion: This is among the largest cohorts of patients to develop RC after ACSS identified to-date and validates a range of independent predictors, many previously only described in case reports. These results are useful for taking preventive measures, identifying high risk patients for preoperative risk stratification, and for surgical co-management discussions with the anesthesiology team.

Obtaining proper lateral full-body X-rays is paramount in accurately and consistently evaluating sagittal spinal alignment. This study explored the patient compliance rate of maintaining standardized arm position (fingers on the clavicles with shoulders in 45° of forward elevation while the patient is in a free-standing posture) during full-body X-rays at a single institution. The compliance rate of arm positioning during full-body X-rays varies depending on operative status (preoperative vs postoperative), age, and diagnosis. Retrospective cohort. Despite the importance of patients maintaining arms in the same position in preoperative and postoperative standing films, patients are known to have their arms in varying positions, confounding radiographic interpretation and making global sagittal and coronal spinal balance assessment variable and potentially less reliable. This study seeks to examine arm position compliance among adult and pediatric surgical spinal deformity patients undergoing total body X-rays over the course of 4 years (2015–2018). A retrospective radiographic review was performed on 382 spinal deformity patients from July 2015 to July 2018. The study’s dependent variable of interest was standardized arm position (fingers on the clavicles with shoulders in 45° of forward elevation while the patient is in a free-standing posture) observed during full-body X-rays obtained for spinal deformity evaluation. Deviations and compliance to the standard protocol for full-body X-ray arm positioning was recorded and analyzed across various independent factors, including year of surgery, pre- and postoperative periods, type of spine surgery, and patient age. Chi-square and Cochran–Armitage analyses were performed to study categorical and trends, respectively. The overall compliance rate for maintaining standardized arm position was 90% for all 370 patients (277 adult and 93 pediatric), in preoperative and postoperative setting. Adults were more likely to follow protocol than pediatric patients (92.9% vs. 82.4%, P value = 0.003). The postoperative setting observed a significantly lower overall compliance rate when compared to the preoperative period (67.8% vs. 87.0%, P value

The purpose of this study was to utilize the National Readmission Database (NRD) to determine estimates for complication rates, 90-day readmission rates, and hospital costs associated with spinal fusion in pediatric patients with Marfan syndrome. The 2012–2015 NRD databases were queried for all pediatric (

Study Design: Consecutively collected cases. Objective: To determine if a machine-learning (ML) program can accurately predict the postoperative thoracic kyphosis through the uninstrumented thoracic spine and pelvic compensation in patients who undergo fusion from the lower thoracic spine (T10 or T11) to the sacrum. Methods: From 2015 to 2019, a consecutive series of adult (≥18 years old) patients with adult spinal deformity underwent corrective spinal fusion from the lower thoracic spine (T10 or T11) to the sacrum. Deidentified data was processed by a ML system-based platform to predict the postoperative thoracic kyphosis (TK) and pelvic tilt (PT) for each patient. To validate the ML model, the postoperative TK (T4-T12, instrumented thoracic, and uninstrumented thoracic) and the pelvic tilt were compared against the predicted values. Results: A total of 20 adult patients with a minimum 6-month follow-up (mean: 22.4 ± 11.3 months) were included in this study. No significant differences were observed for TK (predicted 37.6° vs postoperative 38.3°, P = .847), uninstrumented TK (predicted 33.9° vs postoperative 29.8°, P = .188), and PT (predicted 23.4° vs postoperative 22.7°, P = .754). The predicted PT and the TK of the uninstrumented thoracic spine correlated well with postoperative values (uninstrumented TK: R2 = 0.764, P < .001; PT: R2 = 0.868, P < .001). The mean error with which kyphosis through the uninstrumented thoracic spine can be measured was 4.8° ± 4.0°. The mean error for predicting PT was 2.5° ± 1.7°. Conclusion: ML algorithms can accurately predict the spinopelvic compensation after spinal fusion from the lower thoracic spine to the sacrum. These findings suggest that surgeons may be able to leverage this technology to reduce the risk of proximal junctional kyphosis in this population.

Background Context Understanding the scope of the volume and costs of lumbar fusions and discectomy procedures, as well as identifying significant trends within the Medicare system, may be beneficial in enhancing cost-efficiency and care delivery. However, there is a paucity of studies which analyze recent trends in lumbar fusion volume, utilization, and reimbursements. Purpose This study seeks to define the costs of lumbar fusions and discectomy procedures and identify trends and variations in volume, utilization, and surgeon and hospital reimbursement rates in the Medicare system between 2012 and 2017. Study Design Retrospective database study Patient Sample Medicare Part A and Part B claims submitted for lumbar spine procedures from 2012 to 2017, as documented in the Centers for Medicare & Medicaid Services (CMS) Physician and Other Supplier Public Use Files. Outcome Measures Procedure numbers and payments per episode. Methods This cross-sectional study tracked annual Medicare claims and payments to spine surgeons using publicly-available databases and aggregated data at the county level. Descriptive statistics and multivariate regression models were used to evaluate trends in procedure volume, utilization rates (per 10,000 Medicare beneficiaries), and reimbursement rates, and to examine associations between county-specific and lumbar spine procedure utilization and reimbursements. Results A total of 772,532 lumbar spine procedures were performed in the Medicare population from 2012 to 2017, including 634,335 lumbar fusion surgeries and 138,197 primary lumbar discectomy and microdiscectomy single-level surgeries. There was a 26.0% increase in annual lumbar fusion procedure volume during the study period, with a compound annual growth rate (CAGR) of 4.7%. Lumbar discectomy/microdiscectomy experienced a 23.5% decrease in annual procedure volume (CAGR, -5.2%). Mean Medicare surgeon reimbursements for lumbar fusions nominally decreased by 3.7% from $767 in 2012 to $738 in 2017, equivalent to an inflation-adjusted decrease of 11.4% (CAGR, -0.7%). Mean Medicare payments for lumbar discectomy and microdiscectomy procedures nominally increased by 16.3% from $517 in 2012 to $601 in 2017, equivalent to an inflation-adjusted increase of 6.9% (CAGR, 3.1%). Conclusions This current study found the volume and utilization of lumbar fusions have increased since 2012, while lumbar discectomy and microdiscectomy volume and utilization have fallen. Medicare payments to hospitals and surgeons for lumbar fusions have either declined or not kept pace with inflation, and reimbursements for lumbar discectomy and microdiscectomy to hospitals have risen at a disproportionate rate compared to surgeon payments. These trends in Medicare payments, especially seen in decreasing allocation of reimbursements for surgeons, may be the effect of value-based cost reduction measures, especially for high-cost orthopedic and spine surgeries.

Study Design: Retrospective cohort. Objective: To provide a national-level assessment of the short-term outcomes after spinal deformity surgery in pediatric patients with cerebral palsy. Methods: A national, prospectively collected database was queried to identify pediatric (≤18 years) patients with cerebral palsy, who underwent spinal fusion surgery from 2012 to 2017. Separate multivariate analyses were performed for the primary outcomes of interest including extended length of stay (>75th percentile, >8 days), and readmissions within 90 days after the index admission. Results: A total of 2856 patients were reviewed. The mean age ± standard deviation was 12.8 ± 2.9 years, and 49.4% of patients were female. The majority of patients underwent a posterior spinal fusion (97.0%) involving ≥8 levels (79.9%) at a teaching hospital (96.6%). Top medical complications (24.5%) included acute respiratory failure requiring mechanical ventilation (11.4%), paralytic ileus (8.2%), and urinary tract infections (4.6%). Top surgical complications (40.7%) included blood transfusion (35.6%), wound complication (4.9%), and mechanical complication (2.7%). The hospital cost for patients with a length of hospital stay >8 days ($113 669) was nearly double than that of those with a shorter length of stay ($68 411). The 90-day readmission rate was 17.6% (mean days to readmission: 30.2). The most common reason for readmission included wound dehiscence (21.1%), surgical site infection (19.1%), other infection (18.9%), dehydration (16.9%), feeding issues (14.5%), and acute respiratory failure (13.1%). Notable independent predictors for 90-day readmissions included preexisting pulmonary disease (odds ratio [OR] 1.5), obesity (OR 3.4), cachexia (OR 27), nonteaching hospital (OR 3.5), inpatient return to operating room (OR 1.9), and length of stay >8 days (OR 1.5). Conclusions: Efforts focused on optimizing the perioperative pulmonary, hematological, and nutritional status as well as reducing wound complications appear to be the most important for improving clinical outcomes.

Study design Retrospective cohort study OBJECTIVE.: This study seeks to identify recent trends in utilization and reimbursements of these procedures between 2012and 2017, a period which experienced a change in national guideline recommendations for these procedures. Summary of background data Minimally invasive vertebral augmentation procedures, including vertebroplasty and kyphoplasty, have been typically reserved for fractures associated with refractory pain, deformity, or progressive neurological symptoms. However, controversy exists regarding the safety and effectiveness of these procedures, in particular vertebroplasty. Methods Annual Medicare claims and payments to surgeons were aggregated at the county level to assess regional trends. Descriptive statistics and multivariate regression models were used to evaluate trends in procedure volume, utilization rates, and reimbursement rates, and to examine associations between county-specific variables and outcome variables. Results A total of 24,316 vertebroplasties and 138,778 kyphoplasties were performed in the Medicare population between 2012 and 2017. Annual vertebroplasty volume fell by 48.0% from 5744 procedures in 2012 to 2987 in 2017, with a compound annual growth rate (CAGR) of -12.3%. Annual kyphoplasty volume also declined by 12.7% (CAGR -2.7%), from 24,986 in 2012 to 21,681 in 2017. Surgeon reimbursements for vertebral augmentation procedures increased by a weighted average of 93.7% (inflation-adjusted increase of 78.2%) between 2012 and 2017, which was primarily driven by a dramatic 113.3% (inflation-adjusted increase of 96.2%) increase in mean reimbursements for kyphoplasty procedures from an average of $895 to $1764, between 2012 and 2017, respectively. Conclusion This large national Medicare database study found that vertebroplasty and kyphoplasty procedure volume and utilization of both procedures have declined significantly. Although average reimbursements to surgeons for vertebroplasties have significantly declined, payments for kyphoplasty procedures have risen significantly. Although vertebroplasty volume has significantly decreased, it is still being performed and being reimbursed for, in spite of its controversial role in its treatment of vertebral fractures. Level of evidence 3.

Cervical disc arthroplasty (CDA) has become an increasingly popular treatment for cervical degenerative disc disease. One potential complication is osteolysis. However, current literature on this topic appears limited. The purpose of this study is to elucidate the incidence, aetiology, consequence, and subsequent treatment of this complication. A systematic literature review was performed according to the PRISMA guidelines. Studies discussing the causes, incidence and management of osteolysis after a CA were included. A total of nine studies were included. We divided these studies into two groups: (1) large case series in which an active radiological evaluation for osteolysis was performed (total = six studies), (2) case report studies, which discussed symptomatic cases of osteolysis (total = three). The incidence of asymptomatic osteolysis ranged from 8 to 64%; however, only one study reported an incidence of 1 year) as well. Symptomatic patients with osteolysis often required revision surgery. These patients required removal of implant and conversion to fusion in the majority of the cases. Osteolysis after CDA is common; however, the majority of cases have only mild or asymptomatic presentations that do not require revision surgery. The timing of osteolysis varies significantly. This may be due to differences in the aetiology of osteolysis.

Study Design: Systematic review. Objectives: This current systematic review seeks to identify current applications and surgical outcomes for 3-dimensional printing (3DP) in the treatment of adult spinal deformity. Methods: A comprehensive search of publications was conducted through literature databases using relevant keywords. Inclusion criteria consisted of original studies, studies with patients with adult spinal deformities, and studies focusing on the feasibility and/or utility of 3DP technologies in the planning or treatment of scoliosis and other spinal deformities. Exclusion criteria included studies with patients without adult spinal deformity, animal subjects, pediatric patients, reviews, and editorials. Results: Studies evaluating the effect of 3DP drill guide templates found higher screw placement accuracy in the 3DP cohort (96.9%), compared with non-3DP cohorts (81.5%, P < .001). Operative duration was significant decreased in 3DP cases (378 patients, 258 minutes) relative to non-3DP cases (301 patients,272 minutes, P < .05). The average deformity correction rate was 72.5% in 3DP cases (245 patients). There was no significant difference in perioperative blood loss between 3DP (924.6 mL, 252 patients) and non-3DP cases (935.6 mL, 177 patients, P = .058). Conclusions: Three-dimensional printing is currently used for presurgical planning, patient and trainee communication and education, pre- and intraoperative guides, and screw drill guides in the treatment of scoliosis and other adult spinal deformities. In adult spinal deformity, the usage of 3DP guides is associated with increased screw accuracy and favorable deformity correction outcomes; however, average costs and production lead time are highly variable between studies.

Study Design: Retrospective cohort study. Objectives: Although cervical disc arthroplasty (CDA) has become a well-established and effective treatment for symptomatic cervical degeneration, many patients with multilevel disease are not good candidates for CDA at all levels. For such patients, hybrid surgery (HS)—a combination of adjacent anterior cervical discectomy and fusion (ACDF) and CDA—may be more appropriate. Given the novelty of HS and the relative dearth of studies adequately assessing short-term perioperative complications, this current study sought to assess the short-term morbidity profile of HS, differences in operative duration, length of stay (LOS), and readmission and reoperation rates and reasons relative to a 2-level ACDF cohort. Methods: All patients who underwent HS and 2-level ACDF were identified between 2011 and 2018 using a large, prospectively collected registry. Baseline patient characteristics and postoperative complications were compared using bivariate and/or multivariate analysis. Results: A total of 390 patients undergoing HS were identified. Two-level procedures were the most common (74.9%). Patients undergoing HS were more likely to be younger, male, and have fewer comorbidities. There were no differences between HS and 2-level ACDF in rates of any postoperative complication, transfusion, readmissions, and operative duration. However, HS had a decreased LOS (0.5 days), relative to a 2-level ACDF. HS patients had low rates of reoperation (1.28%) with 1 case for hematoma evacuation and another for revision CDA. Conclusions: This study represents one of the largest cohorts of patients undergoing HS reported to date. Patients undergoing HS are not at increased risk of perioperative complications relative to a 2-level ACDF and may benefit from shorter LOS.

Study design Expert Consensus Study. Objectives This expert panel was created to establish best practice guidelines to identify and treat patients with poor bone health prior to elective spinal reconstruction. Summary of background data Currently, no guidelines exist for the management of osteoporosis and osteopenia in patients undergoing spinal reconstructive surgery. Untreated osteoporosis in spine reconstruction surgery is associated with higher complications and worse outcomes. Methods A multidisciplinary panel with 20 experts was assembled including orthopedic and neurological surgeons, endocrinologists, and rheumatologists. Surveys and discussions regarding the current literature were held according to Delphi method until a final set of guidelines was created with over 70% consensus. Results Panelists agreed that bone health should be considered in every patient prior to elective spinal reconstruction. All patients above 65 and those under 65 with particular risk factors (chronic glucocorticoid use, high fracture risk or previous fracture, limited mobility, and eight other key factors) should have a formal bone health evaluation prior to undergoing surgery. DXA scans of the hip are preferable due to their wide availability. Opportunistic CT Hounsfield Units of the vertebrae can be useful in identifying poor bone health. In the absence of contraindications, anabolic agents are considered first line therapy due to their bone building properties as compared to antiresorptive medications. Medications should be administered preoperatively for at least 2 months and postoperatively for minimum 8 months. Conclusions Based on the consensus of a multidisciplinary panel of experts, we propose best practice guidelines for assessment and treatment of poor bone health prior to elective spinal reconstructive surgery. Patients above age 65 and those with particular risk factors under 65 should undergo formal bone health evaluation. We also established guidelines on perioperative optimization, utility of various diagnostic modalities, and the optimal medical management of bone health in this population.Level of Evidence: 5.

BACKGROUND: The purpose of this study was to identify the risk factors that are significantly associated with hospital length of stay (LOS) following geriatric hip fracture and to use these significant variables to develop a LOS calculator. MATERIALS AND METHODS: This was a retrospective study examining 614 patients treated for geriatric hip fracture between January 2000 and December 2009 at an urban, Level 1 trauma center. A negative binomial regression analysis was used to identify perioperative variables associated with hospital LOS. RESULTS: 614 patients met the inclusion criteria, presenting with a mean age of 78 (±10) years. The most common pre-operative comorbidity was hypertension, followed by diabetes and COPD. After controlling for all collected comorbidities as well as demographics and operative variables, hypertension (IRR: 1.10, p = 0.029) and disseminated cancer (IRR: 1.24, p = 0.007) were found to be significantly associated with LOS. In addition, two demographic/presenting variables, admission to the medicine service (IRR: 1.48, p

Background: This registry study assesses 30-day outcomes, including complications, length of stay (LOS), transfusions, and discharge disposition, as a function of time to revision surgery for knee periprosthetic fracture (PPF). Methods: We compared outcomes when surgery occurred ≤ (expedited) or > 24 hours (nonexpedited) after admission using the 2005-2016 National Surgical Quality Improvement Program registry. Outcome variables were assessed using bivariate and multivariate analyses. Results: Of 484 patients undergoing revision knee arthroplasty for PPF, 337 (77.9%) had expedited surgery and 107 (22.1%) had nonexpedited surgery. The average time to surgery in the nonexpedited group was 3.2 days (range 0-11). Patients with nonexpedited surgery were more likely to be older, female, and diabetic, received general anesthesia, and had a higher American Society of Anesthesiologists class, dependent functional status, and longer operative time. On multivariate analysis, nonexpedited patients had more complications (odds ratio [OR], 2.35; P = 0.037), surgical site infections (OR, 12.87; P = 0.029), urinary tract infections (OR, 10.46; P = 0.048), nonhome discharge (OR, 4.27; P < 0.001), need for blood transfusion (OR, 4.53; P < 0.001), and longer LOS (2.4 days; P < 0.001). There was no difference in mortality (P = 0.352). Conclusions: Nonexpedited revision surgery for knee PPF had worse outcomes, specifically more surgical site and urinary tract infections, longer LOS, need for blood products, and more discharge to acute care facilities. This registry study cannot assess reasons for unavoidable delay, such as medical optimization and team or implant availability. Level of Evidence: III. Keywords: Peri-prosthetic fracture, Knee arthroplasty, Fracture outcomes, Knee arthroplasty fracture, Peri-prosthetic outcomes

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.

Background Robot-assisted platforms in spine surgery have rapidly developed into an attractive technology for both the surgeon and patient. Although current literature is promising, more clinical data is needed. The purpose of this paper is to determine the effect of robot-related complications on clinical outcomes Methods This multicenter study included adult (≥18 years old) patients who underwent robot-assisted lumbar fusion surgery from 2012-2019. The minimum follow-up was 1 year after surgery. Both bivariate and multivariate analyses were performed to determine if robot-related factors were associated with reoperation within 1 year after primary surgery. Results A total of 320 patients were included in this study. The mean (standard deviation) Charlson Comorbidity Index was 1.2 (1.2) and 52.5% of patients were female. Intraoperative robot complications occurred in 3.4% of patients and included intraoperative exchange of screw (0.9%), robot abandonment (2.5%), and return to the operating room for screw exchange (1.3%). The 1-year reoperation rate was 4.4%. Robot factors, including robot time per screw, open vs. percutaneous, and robot system, were not statistically different between those who required revision surgery and those who did not (P>0.05). Patients with robot complications were more likely to have prolonged length of hospital stay and blood transfusion, but were not at higher risk for 1-year reoperations. The most common reasons for reoperation were wound complications (2.2%) and persistent symptoms due to inadequate decompression (1.5%). In the multivariate analysis, robot related factors and complications were not independent risk factors for 1-year reoperations. Conclusion This is the largest multicenter study to focus on robot-assisted lumbar fusion outcomes. Our findings demonstrate that 1-year reoperation rates are low and do not appear to be influenced by robot-related factors and complications; however, robot-related complications may increase the risk for greater blood loss requiring a blood transfusion and longer length of stay.

OBJECTIVE The authors’ objectives were: 1) to evaluate the incidence and risk factors of iatrogenic coronal malalignment (CM), and 2) to assess the outcomes of patients with all three types of postoperative CM (iatrogenic vs unchanged/worsened vs improved but persistent). METHODS A single-institution, retrospective cohort study was performed on adult spinal deformity (ASD) patients who underwent > 6-level fusion from 2015 to 2019. Iatrogenic CM was defined as immediate postoperative C7 coronal vertical axis (CVA) ≥ 3 cm in patients with preoperative CVA < 3 cm. Additional subcategories of postoperative CM were unchanged/worsened CM, which was defined as immediate postoperative CVA within 0.5 cm of or worse than preoperative CVA, and improved but persistent CM, which was defined as immediate postoperative CVA that was at least 0.5 cm better than preoperative CVA but still ≥ 3 cm; both groups included only patients with preoperative CM. Immediate postoperative radiographs were obtained when the patient was discharged from the hospital after surgery. Demographic, radiographic, and operative variables were collected. Outcomes included major complications, readmissions, reoperations, and patient-reported outcomes (PROs). The t-test, Kruskal-Wallis test, and univariate logistic regression were performed for statistical analysis. RESULTS In this study, 243 patients were included, and the mean ± SD age was 49.3 ± 18.3 years and the mean number of instrumented levels was 13.5 ± 3.9. The mean preoperative CVA was 2.9 ± 2.7 cm. Of 153/243 patients without preoperative CM (CVA < 3 cm), 13/153 (8.5%) had postoperative iatrogenic CM. In total, 43/243 patients (17.7%) had postoperative CM: iatrogenic CM (13/43 [30.2%]), unchanged/worsened CM (19/43 [44.2%]), and improved but persistent CM (11/43 [25.6%]). Significant risk factors associated with iatrogenic CM were anxiety/depression (OR 3.54, p = 0.04), greater preoperative sagittal vertical axis (SVA) (OR 1.13, p = 0.007), greater preoperative pelvic obliquity (OR 1.41, p = 0.019), lumbosacral fractional (LSF) curve concavity to the same side of the CVA (OR 11.67, p = 0.020), maximum Cobb concavity opposite the CVA (OR 3.85, p = 0.048), and three-column osteotomy (OR 4.34, p = 0.028). In total, 12/13 (92%) iatrogenic CM patients had an LSF curve concavity to the same side as the CVA. Among iatrogenic CM patients, mean pelvic obliquity was 3.1°, 4 (31%) patients had pelvic obliquity > 3°, mean preoperative absolute SVA was 8.0 cm, and 7 (54%) patients had preoperative sagittal malalignment. Patients with iatrogenic CM were more likely to sustain a major complication during the 2-year postoperative period than patients without iatrogenic CM (12% vs 33%, p = 0.046), yet readmission, reoperation, and PROs were similar. CONCLUSIONS Postoperative iatrogenic CM occurred in 9% of ASD patients with preoperative normal coronal alignment (CVA < 3 cm). ASD patients who were most at risk for iatrogenic CM included those with preoperative sagittal malalignment, increased pelvic obliquity, LSF curve concavity to the same side as the CVA, and maximum Cobb angle concavity opposite the CVA, as well as those who underwent a three-column osteotomy. Despite sustaining more major complications, iatrogenic CM patients did not have increased risk of readmission, reoperation, or worse PROs.

BACKGROUND: Generally, most spine surgeons agree that increased segmental motion viewed on flexion-extension radiographs is a reliable predictor of instability; however, these views can be limited in several ways and may underestimate the instability at a given lumbar segment. METHODS: Consecutively collected adult (≥18 years old) patients with symptomatic single-level lumbar spondylolisthesis were reviewed from a two-surgeon database from 2015 to 2019. Routine standing lumbar X-rays (neutral, flexion, extension) and supine lumbar MRI (sagittal T2-weighted imaging sequence) were performed. Patients were excluded if they had prior lumbar surgery, missing radiographic data, or if the time between X-rays and MRI was >6 months. RESULTS: All 39 patients with symptomatic, single-level lumbar spondylolisthesis were identified. The mean age was 57.3±16.7 years and 66% were female. There was good intra- and inter-rater reliability agreement between measured values on the presence of instability. The slip percentage (SP) difference was significantly highest in the flexion-supine (FS) (5.7 mm, 12.3%) and neutral standing-supine (NS) (4.3 mm, 8.7%) groups, both of which were significantly higher compared with the flexion-extension (FE) group (1.8 mm, 4.5%, P8% was observed more frequently in FS (79.5%) and NS (52.6%) groups compared with FE group (16.7%, P

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 Little is known regarding the incidence and risk factors for postop CM after ASD surgery. PURPOSE A subset of patients undergoing adult spinal deformity (ASD) surgery will have postoperative coronal malalignment (CM) with suboptimal outcomes. STUDY DESIGN/SETTING Retrospective cohort. PATIENT SAMPLE A total of 243 adult spinal deformity patients. OUTCOME MEASURES Postoperative Coronal Malalignment. METHODS 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. RESULTS 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. CONCLUSIONS 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. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Study Design: Retrospective cohort. Objective: Provide a comparison of surgical approach in the treatment of degenerative cervical myelopathy in patients with OPLL. Methods: A national database was queried to identify adult (≥18 years) patients with OPLL, who underwent at least a 2-level cervical decompression and fusion for cervical myelopathy from 2012-2014. A propensity-score-matching algorithm was employed to compare outcomes by surgical approach. Results: After propensity-score matching, 627 patients remained. An anterior approach was found to be an independent predictor for higher inpatient surgical complications(OR 5.9), which included dysphagia:14%[anterior]vs.1.1%[posterior] P-value < 0.001, wound hematoma:1.7%[anterior]vs.0%[posterior] P-value = 0.02, and dural tear:9.4%[anterior]vs.3.2%[posterior] P-value = 0.001. A posterior approach was an predictor for longer hospital length of stay by nearly 3 days(OR 3.4; 6.8 days[posterior]vs.4.0 days[anterior] P-value < 0.001). The reasons for readmission/reoperation did not vary by approach for 2-3-level fusions; however, for >3-level fusions, patients with an anterior approach more often had respiratory complications requiring mechanical ventilation( P-value = 0.038) and required revision fusion surgery( P-value = 0.015). Conclusions: The national estimates for inpatient complications(25%), readmissions(9.9%), and reoperations(3.5%) are substantial after the surgical treatment of multi-level OPLL. An anterior approach resulted in significantly higher inpatient surgical complications, but this did not result in a longer hospital length of stay and the overall 90-day complication rates requiring readmission or reoperation was similar to those seen after a posterior approach. For patients requiring >3-level fusion, an anterior approach is associated with significantly higher risk for respiratory complications requiring mechanical ventilation and revision fusion surgery. Precise neurological complications and functional outcomes were not included in this database, and should be further assessed in future studies.

Study Design: Retrospective study. Objective: To examine the associated indications, procedures, and postoperative outcomes after revision ACDA. Methods: We utilized a national database to identify adult(≥18 years) patients who underwent either a primary ACDA or removal of ACDA over a 10-year period(2008-2017). An in-depth assessment of the reasons for revision surgery and the subsequent procedures performed after the removal of ACDA was done by using both Current Procedural Terminology(CPT) and International Statistical Classification of Diseases (ICD-9,10) coding. Results: From 2008 to 2017, a total of 3,350 elective, primary ACDA cases were performed. During this time, 69 patients had a revision surgery requiring the removal of ACDA. The most common reasons for revision surgery included cervical spondylosis(59.4%) and mechanical complications(27.5%). After removal of ACDA, common procedures performed included anterior cervical fusion with or without decompression(69.6%), combined anterior/posterior fusion/decompression (11.6%), and replacement of ACDA (7.2%). The indications for surgery did not vary significantly among the different procedures performed (p = 0.318). Patients requiring revision surgery for mechanical complications or those who underwent a combined surgical approach were at significantly higher risk for subsequent short-term complications (pConclusion: Over a 10-year period, the rate of revision surgery for ACDA was low (2.1%). Nearly 90% of revision cases were due to either cervical spondylosis or mechanical complications. These indications for surgery did not vary significantly among the different procedures performed. These findings will be important during the shared-decision making process for patients undergoing primary or revision ACDA.

Study Design: Retrospective Cohort. Objective: To compare the short-term outcomes for Laminoplasty, Laminectomy/fusion, and ACDF. Methods: We utilized a prospectively-collected, multi-center national database with a propensity score matching algorithm to compare the short-term outcomes for laminoplasty, laminectomy/fusion, and multi-level (>3) ACDF (with and without corpectomy). Bivariate analyses involved both chi-square/fisher exact test and t-test/ANOVA on perioperative factors. Multivariate analyses were performed to determined independent risk factors for short term outcomes. Results: 546 patients remained after propensity score matching, with 182 patients in each cohort. ACDF required the longest operative time 188 ± 79 versus laminectomy/fusion (169 ± 75, p = 0.017), and laminoplasty (167 ± 66, p = 0.004). ACDF required the shortest hospital stay (LOS ≥ 2: ACDF 56.6%, laminoplasty 89.6%, laminectomy/fusion 93.4%, p < 0.05). ACDF had lower overall complications (ACDF 3.9%, laminoplasty 7.7%, laminectomy/fusion 11.5%, p < 0.05), mortality (ACDF 0%, laminoplasty 0.55%, laminectomy/fusion 2.2%, p < 0.05), and unplanned readmissions (ACDF 4.4%, laminoplasty 4.4%, laminectomy/fusion 9.9%, p < 0.05). No significant differences were seen in the other outcomes including DVT/PT, acute renal failure, UTI, stroke, cardiac complications, or sepsis. In the multivariate analysis, laminectomy/fusion (OR 17, reference: ACDF) and laminoplasty (OR10, reference: ACDF) were strong independent risk factors for LOS ≥ 2 days. Laminectomy/fusion (OR 3.2, reference: ACDF) was an independent predictor for any adverse events 30-days after surgery. Conclusions: Laminectomy/fusion carries the highest risk for morbidity, mortality, and unplanned readmissions in the short-term postoperative period. Laminoplasty and ACDF cases carry similar short-term complications risks. ACDF is significantly associated with the longest operative duration and shortest LOS without an increase in individual or overall complications, readmissions, or reoperations

STUDY DESIGN Retrospective cohort study. OBJECTIVE The purpose of this study was to utilize the National Readmission Database to determine the national estimates of complication and 90-day readmission rates associated with cervical spinal fusion in adult patients with rheumatoid arthritis (RA). SUMMARY OF BACKGROUND RA patients who undergo cervical spine surgery are known to be at high risk for readmissions, which are costly and may not be reimbursed by Medicare. METHODS The National Readmission Database was queried for adults (>18 years) diagnosed with RA undergoing cervical spine fusion. Patient, operative, and hospital factors were assessed in bivariate analyses. Independent risk factors for readmissions were identified using stepwise multivariate logistic regression. RESULTS From 2013 to 2014, a total of 5597 RA patients (average age: 61.5 ± 11.2 years, 70.9% female) underwent cervical spine fusion. A total of 691 (12.3%) patients were readmitted within 90 days (). Index inpatient complications included dysphagia (readmitted: 7.9% vs. non-readmitted: 5.1%; P = 0.003), urinary tract infection (UTI) (8.8% vs. 3.7%; P < 0.001), respiratory-related complications (7.6% vs. 3.4%; P < 0.001), and implant-related complications (5.4% vs. 2.7%; P < 0.001). Multivariate logistic regression demonstrated the following as the strongest independent predictors for 90-day readmission: intraoperative bleeding (odds ratio [OR]: 3.6, P = 0.001), inpatient Deep Vein Thrombosis (DVT) (OR 4.1, P = 0.004), and patient discharge against medical advice (OR 33.5, P = 0.001). CONCLUSION Readmission rates for RA patients undergoing cervical spine surgery are high and most often due to postoperative infection (septicemia, UTI, pneumonia, wound). Potential modifiable factors which may improve outcomes include minimizing intraoperative blood loses, postoperative DVT prophylaxis, and discharge disposition. LEVEL OF EVIDENCE 3.

Study Design: Retrospective review. Objective: Identify surgical complex adult spine deformity patients who are at increased risk for an unplanned postoperative 90-day readmission and/or reoperation. Methods: A total of 227 consecutive records of complex adult (≥18 years old) spine deformity surgeries from 2015 to 2018 were reviewed. Demographics, comorbidities, operative details, and postoperative complication data was collected. Chi-square/Fisher’s exact test and t tests were used for bivariate analysis. To determine independent predictors for readmissions/reoperations, stepwise multivariate logistic regressions were employed. The C-statistic and Hosmer-Lemeshow (HL) value was used to measure concordance and goodness of fit. Results: Average age was 50.5 ± 17.8 years and 67.8% were female. Ninety-day readmission and reoperation rates were 7.0% and 5.3%, respectively. Median number of days after index discharge date resulting in readmission and reoperation were 16.5 and 28, respectively. The multivariate regression for 90-day readmissions included pulmonary comorbidity, depression, history of deep vein thrombosis/pulmonary embolism (DVT/PE), and gastrointestinal comorbidity (C-statistic = 0.82; HL = 0.79). Pulmonary comorbidity, depression, and history of DVT/PE increased risk for 90-day readmission by 5-, 3.5-, and 10.2-fold, respectively. The multivariate regression for 90-day reoperations was similar to readmissions (C-statistic = 0.89; HL = 0.31). Operative time>7 hours and history of DVT/PE increased risk for early reoperation by 5.8- and 8.7-fold, respectively. Conclusions: An emphasis on medically optimizing patients with preexisting pulmonary comorbidities, depression, and history of DVT/PE may have a substantial impact on improving short-term outcomes in this population. The present study provides benchmark data and may serve as an initial model to predict unplanned reoperations and readmissions.

Pseudarthrosis remains a major complication for patients undergoing anterior cervical discectomy and fusion (ACDF; 0%-15% at 1-year follow-up). Potentially modifiable risk factors are known in literature, such as smoking and osteoporosis. Biomechanical studies suggest that plates with locking screws can enhance the fixation rigidity and pull-out strength. Although longer screws are known to be correlated with increased pull-out strength, deeper screw depths can increase the risk for intraoperative complications. An important factor that has yet to be studied is the minimum screw length relative to the diameter of the vertebral body (VB) necessary to achieve successful fusion. In this study, we hypothesize that screws with shorter depths relative to the VB will increase the risk for radiographic pseudarthrosis and result in poor patient reported outcomes (PROs).To examine the impact of ACDF screw length on pseudarthrosis risk.A review of prospectively collected data.A total of 85 patients were included in this study. The mean age ±standard deviation was 58.9±10.3 and 42.4% of patients were female. The mean follow-up was 21.6±8.3 months.The neck disability index (NDI) was used to assess PROs up to 2-years after surgery. For each ACDF level, the screw length and VB% (screw length divided by the anterior-posterior VB diameter) were measured. Radiographic pseudarthrosis (interspinous motion [ISM] ≥1 mm) was recorded at 6-weeks, 6-months, and 1-year for each patient. The positive and negative predictive values (PPV, NPV) for ISM ≥ 1mm were measured for different VB% thresholds. A VB% of75% was found to have the highest PPV (93%) and NPV (70%) for radiographic pseudarthrosis. This threshold of75% was then assessed in our bivariate and multivariate analyses.We reviewed a database (2015-2018) of adult (≥18 years old) patients who underwent a primary two-level ACDF with or without corpectomy. All ACDF constructs involved fixed angle screws. The minimum follow-up period was 1 year. Multivariate analyses were performed to determine if screw VB% was an independent risk factor for radiographic pseudarthrosis.By 1-year, overall fusion success was achieved in 92.9% of patients. The 1-year revision rate was 4.7%. Patients with any screw VB%75% had substantially worse fusion success (64.3%) than those who did not (98.6%) at 1-year. The VB%75% increased the risk for radiographic pseudarthrosis at every follow up period. In comparison to other time-points, patients with radiographic pseudarthrosis at 6 weeks had significantly worse NDI scores by 2-years (p=.047). The independent risk factors for radiographic pseudarthrosis at 6-weeks included any screw VB%75% (OR 77, p.001), prior/current smoker (OR 6.8, p=.024), and corpectomy (OR 0.1, p=.010). Patients with ISM≥1 mm had a higher rate of revision surgery at 1-year (5.9% vs. 3.9%), but this was not statistically significant (p=.656).In primary two-level ACDF, VB%75% is significantly associated with increased ISM (≥1 mm) at all time points for this study. As an intraoperative guide, spine surgeons can use the screw VB% threshold of75% to avoid unnecessarily short screws. This threshold can be easily measured pre- and intraoperatively, and has been found to be strongly correlated to radiographic pseudarthrosis in the early postoperative period.

Study Design: Retrospective study. Objective: To determine the rates of early postoperative mortality and morbidity in adults with hypoalbuminemia undergoing elective posterior lumbar fusion (PLF). Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) was examined from 2005 to 2012. Current Procedural Terminology (CPT) codes were used to query the database for adults (≥18 years) who underwent PLF and/or posterior/transforaminal lumbar interbody fusion (PLIF/TLIF). Patients were divided into those with normal albumin concentration (≥3.5g/dL) and those with hypoalbuminemia (Results: A total of 2410 patients were included, of whom 2251 (93.4%) were normoalbuminemic and 159 (6.6%) were hypoalbuminemic. Patients with preoperative serum albumin levels 5 days ( P < .001). However, hypoalbuminemia was not significantly associated with any specific perioperative complication. On multivariate analysis, preoperative hypoalbuminemia was found to be an independent predictor of prolonged LOS (OR 2.4, 95% CI 1.7-3.5; P < .001) and unplanned readmission (OR 2.7, 95% CI 1.1-6.3; P = .023). Conclusion: Hypoalbuminemia was found to be an important predictor of patient outcomes in this population. This study suggests that clinicians should consider nutritional screening and optimization as part of the preoperative risk assessment algorithm. Level of Evidence: III

Study Design:Retrospective analysis.Objective:The incidence of intradural extramedullary (IDEM) spinal tumors is increasing. Excisional laminectomy for removal and decompression is the standard of care, but complications associated with patient age are unreported in the literature. Our objective is to identify if age is a risk factor for postoperative complications after excisional laminectomy of IDEM spinal tumors.Methods:A retrospective analysis was performed on the 2011 to 2014 ACS-NSQIP (American College of Surgeons National Surgical Quality Improvement Program) database for patients undergoing excisional laminectomy of IDEM spinal tumors. Age groups were determined by interquartile analysis. Chi-squared tests, t tests, and multivariate logistic regression models were employed to identify independent risk factors. Institutional review board approval was not needed.Results:A total of 1368 patients met the inclusion criteria for the study. Group 1 (age ≤ 44) contained 372 patients, group 2 (age 45-54) contained 314 patients, group 3 (age 55-66) contained 364 patients, and group 4 (age > 66) contained 318 patients. The univariate analysis showed that mortality and unplanned readmission were highest among patients in group 4 (1.26%, P = .011, and 10.00%, P = .039, respectively). Postoperative wound complications were highest among patients in group 1 (2.15%, P = .009), and postoperative venous thromboembolism and cardiac complications were highest among patients in group 3 (4.4%, P = .007, and 1.10%, P = .032, respectively). Multivariate logistic regression revealed that elderly age was an independent risk factor for postoperative venous thromboembolism (group 3 vs group 1; odds ratio = 6.739, confidence interval = 1.522-29.831, P = .012).Conclusions:This analysis revealed that increased age is an independent risk factor for postoperative venous thromboembolism in patients undergoing excisional laminectomy for IDEM spinal tumors.

Study Design: Retrospective propensity score matched analysis. Objective: To compare the incidence of any 30-day perioperative complication following primary and revision discectomy for lumbar disc herniation. Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) was used to identify patients undergoing primary or revision lumbar discectomy from 2005 to 2012. Propensity score matching was performed to create matched pairs of primary and revision discectomy cases for analysis. Univariate analysis was then performed to compare 30-day morbidity and mortality between propensity score–matched pairs. Results: We identified 4730 cases of primary discectomy performed through a minimally invasive or open approach and 649 revision discectomy cases. Baseline patient characteristics and comorbidities were compared and then propensity score–matched adjustments were made to create 649 matched pairs of primary and revision cases. On univariate analysis, there were no significant differences in 30-day perioperative outcomes between the 2 groups. Conclusion: While there were no significant differences in 30-day perioperative complications between patients undergoing primary lumbar discectomy and those undergoing revision lumbar discectomy, this finding should be interpreted with caution since the ACS-NSQIP database lacks functional and pain outcomes, and also does not include dural tear or durotomy as a complication. Future large-scale and long-term prospective studies including these variables are needed to better understand the outcomes and complications following primary versus revision discectomy for lumbar disc herniation.

STUDY DESIGN Retrospective study of prospectively collected data. OBJECTIVE To analyze the incidence and risk factors for readmissions following anterior lumbar interbody fusion. SUMMARY OF BACKGROUND DATA No study has yet reported readmission rates for a specific lumbar surgical approach. There is evidence to indicate differences in perioperative complication rates between anterior versus posterior lumbar interbody fusion techniques, which may translate into differences in readmission rates. METHODS The American College of Surgeons National Surgical Quality Improvement Program is a large multicenter clinical registry that prospectively collects preoperative risk factors, intraoperative variables, and 30-day postoperative morbidity and mortality outcomes from about 400 hospitals nationwide. Current Procedural Terminology codes were used to query the database for adults who underwent anterior lumbar interbody fusion. Patients were separated into groups of those with and without 30-day readmissions. Univariate analysis and multivariate logistic regression were used to analyze the effect of different risk factors on 30-day readmissions. RESULTS Multivariate analysis showed that morbid obesity (odds ratio 15.6, P = 0.002) and alcohol use (odds ratio 16.9, P = 0.004) independently predicted unplanned 30-day readmission. Sex, pulmonary comorbidity, cardiac comorbidity, and steroid use were not found to be significant independent predictors of unplanned 30-day readmission in anterior lumbar interbody fusion. CONCLUSION Adult patients undergoing anterior lumbar interbody fusion who were morbidly obese and had history of alcohol use are at increased risk for 30-day readmissions. Future studies should look to directly compare readmission rates and risk factors between alternative lumbar interbody surgical approaches with longer follow-up and more clinical and radiological parameters investigated. LEVEL OF EVIDENCE 3.

Study Design: Retrospective cohort study. Objectives: Diabetes mellitus is a highly prevalent disease in the United States. Adult spinal deformity (ASD) surgery encompasses a wide variety of spinal disorders and is associated with a morbidity rate between 20% and 80%. Considering utilization of spinal surgery will continue to increase, this study investigates the influence of diabetes mellitus on acute postoperative outcomes following elective ASD surgery. Methods: The 2010-2014 American College of Surgeon’s National Surgical Quality Improvement Program database was queried using Current Procedural Terminology and International Classification of Diseases (9th Revision) diagnosis codes relevant to ASD surgery. Patients were divided into cohorts based on their diabetic status. Bivariate and multivariate logistic regression analyses were employed to identify which 30-day postoperative outcomes patients are at risk for. Results: A total of 5809 patients met the inclusion criteria for the study of which 4553 (84.2%) patients were nondiabetic, 578 (10.7%) patients had non–insulin-dependent diabetes mellitus (NIDDM), and 275 (5.1%) patients had insulin-dependent diabetes mellitus (IDDM). Diabetes status was significantly associated with length of stay ≥5 days (NIDDM: odds ratio [OR] = 1.27, 95% confidence interval [CI] = 1.02-1.58, P = .034; IDDM: OR = 1.55, 95% CI = 1.15-2.09, P = .004), any complication (NIDDM: OR = 1.26, 95% CI = 1.01-1.58, P = .037), urinary tract infection (NIDDM: OR = 1.87, 95% CI = 1.14-3.05, P = .012), and cardiac complications (IDDM: OR = 4.05, 95% CI = 1.72-9.51, P = .001). Conclusions: Given the prevalence of diabetes, surgeons will invariably encounter these patients for ASD surgery. The present study identifies the increased risk NIDDM and IDDM patients experience following ASD surgery. Quantification of this increased risk may improve the selection of appropriate surgical candidates, patient risk stratification, and patient postoperative safety.

STUDY DESIGN Retrospective study of prospectively collected data. OBJECTIVE To perform a multiinstitutional assessment on the incidence and risk factors for unplanned readmissions following elective posterior lumbar fusion (PLF) surgery. SUMMARY OF BACKGROUND DATA Understanding what may drive rehospitalizations is a necessary step toward higher quality care. Identifying risk factors for unplanned readmission is especially important for elective PLF, which is a common procedure that is known to be associated with significant adverse events. METHODS Adult patients undergoing PLF were identified using current procedure terminology (CPT) from the American College of Surgeons National Surgical Quality Improvement Program. Both descriptive and comparative statistics were performed for patient characteristics, clinical factors, and postoperative complications. Subsequently, a step-wise multivariate logistic regression was employed. RESULTS Of the 2301 patients who met inclusion criteria for this study, 117 were unplanned readmissions (5.1%). These occurred at a mean of 15.9 days (range: 3-30 days) after surgery. The risk-adjusted analysis revealed that bleeding disorder (odds ratio, OR = 2.8, confidence intervals, CI = 1.0-7.6, P = 0.043), insulin dependent diabetes (OR = 2.5, CI = 1.4-4.4, P = 0.004), and total length of stay > 5 days (OR = 1.8, CI = 1.2-2.8, P = 0.009) were independent predictors for unplanned readmission. Significant postoperative complications included wound complications (OR = 27.6, CI = 13.9-54.8, P

Background The incidence of meningioma has increased drastically recently, particularly in older adults. Surgical intervention has the potential to reduce neurologic symptoms and achieve favorable, long-term outcomes. There is considerable variability in the literature examining the relationship between age and outcomes after meningioma surgery. The objective of this study was to identify the relationship between age and postoperative complications after craniotomy for resection of meningioma. Methods The American College of Surgeons National Surgical Quality Improvement Program database was used to identify patients undergoing craniotomy for meningioma resection between 2005 and 2012. Multivariate analysis was used to identify associations between age and postoperative complications. Results Age >80 years is an independent risk factor for any complication (odds ratio [OR], 2.374; 95% confidence interval [CI], 1.3–4.4; P = 0.015), death within 30 days of surgery (OR, 15.7; 95% CI, 3.0–81.0; P 5 days (OR, 3.2; 95% CI, 1.8–5.6; P Conclusions Advanced age, particularly >80 years, is an independent predictor of morbidity and mortality in patients undergoing craniotomy for resection of meningioma. As such, it should be considered in preoperative optimization and risk stratification.

Objective To examine the complications and patient-reported outcomes after robot-assisted short-segment lumbar fusion surgery. Methods We reviewed a consecutive group of adult patients (≥18 years old) with lumbar degenerative disease who underwent a robot-assisted short lumbar fusion (1-, 2-level) between 2017 and 2019. The minimum follow-up was 1-year. Bivariate and multivariate analyses were performed to determine risk factors for the outcomes. Results A total of 51 patients underwent a robot-assisted short-segment (1-level: N = 33, 64.7%; 2-level: N = 18, 35.3%) lumbar fusion. The mean age ± standard deviation was 55.4 ± 12.9, and 52.9% of patients were female (N = 27). Intraoperative complications included dural tear (N = 3, 5.9%) and exchange of screws for breach (N = 3, 5.9%). No intraoperative motor/sensory loss was observed in this study sample. The mean length of stay was 2.8 ± 1.6 days. The 1-year readmission and reoperation rates were 11.8% (N = 6) and 7.8% (N = 4), respectively. The reasons for revision surgeries included wound complications requiring irrigation and debridement (N = 3) and disc herniation (N = 1, 2%). Overall, our patients experienced substantial improvements in ODI (MCID%: 6-weeks: 60.1%, 6-month: 78.8%, 1-year: 85.4%, and 2-year: 85.7%). For primary 1-level lumbar fusion, there was a significant reduction of 40 min after the first 20 cases (193 ± 30 min vs. 153 ± 55, p = 0.019). Conclusions The findings of our study on robot-assisted short-segment lumbar fusions demonstrate that comparable outcomes can be achieved with robotic assistance compared to those reported for both free-hand technique and other robotic systems in current literature. Most patients can expect to achieve substantial improvements in their PROs despite complications. Even after the first 20 cases, surgeons might experience a significant reduction in operative time using this robotic system.

BACKGROUND CONTEXT 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. PURPOSE Pelvic obliquity (PO) and leg length discrepancy (LLD) are associated with preoperative and postoperative coronal malalignment (CM) in surgical adult spinal deformity (ASD) patients. STUDY DESIGN/SETTING Retrospective cohort. PATIENT SAMPLE A total of 237 patients undergoing ASD surgery at a single institution. OUTCOME MEASURES Pelvic obliquity, leg-length discrepancy, coronal malalignment. METHODS 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. RESULTS 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 CONCLUSIONS 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. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.