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Retrospective cohort study.This study aims to identify differences in perioperative outcomes between ambulatory patients with neuromuscular scoliosis (ANMS) and adolescent idiopathic scoliosis (AIS) following spinal fusion.NMS patients have severe curves with more comorbidities and procedural complexity. These patients require extensive fusion levels, increased blood loss, and suffer increased periop complications. However, NMS patients have a variable severity spectrum, including ambulation status.Chart and radiographic review of NMS and AIS patients undergoing PSF from 2005 to 2018. NNMS included NMS patients who were completely dependent (GMFCS IV-V). ANMS consisted of community ambulators without significant reliance on wheeled assistive devices (GMFCS I-III). Subanalysis matched by age, sex, levels fused and preoperative Cobb angle was conducted as well. Wilcoxon Rank-Sum, Kruskal-Wallis, χ2, and Fisher exact tests were performed.There were 120 patients in the NNMS group, 54 in ANMS and 158 in the AIS group. EBL was significantly lower for ANMS and AIS patients (P 0.001). Complications within 30 days were similar between ANMS and AIS (P = 1.0), but significantly higher for NNMS (P 0.001). Two (1.3%) AIS patients, (1.7%) nonambulatory NMS patients, and one (1.9%) ANMS patient required revision surgery (P = 1.0). However, all NMS patients had increased fusion levels, fixation points, and surgery time (P 0.05). NNMS had significantly longer ICU (P 0.001), hospital stay (P 0.001), intraoperative transfusions (P 0.001), and fewer patients extubated in the OR (P 0.001) than ANMS and AIS patients. In the subanalysis, ANMS had similar radiographic measurements, EBL, transfusion, surgery time, extubation rate, and complication rate (P 0.05) to AIS.Our data show radiographic outcomes, infections, revisions, and overall complications for ANMS were similar to the AIS population. This suggests that NMS patients who ambulate primarily without assistance can expect surgical outcomes comparable to AIS patients with further room for improvement in length of ICU and hospital stay.Level of Evidence: 4.

BACKGROUND/INTRODUCTION Pedicle screws have long been part of the continued advancements in spine surgery. Despite the many techniques that have been devised for their safe placement, malposition of screws continues to occur. Studies have evaluated the possible safe limits of screw malposition, and have given some insight on anatomic variation in spinal deformity. Review of the literature reveals several cases of deleterious long-term sequelae of malpositioned screws. DISCUSSION With the current experience, proposed recommendations are provided to detect and avoid the potential long-term sequelae. Though the literature has helped to define possible concerning screws, there are no good studies predicting long-term risk. CONCLUSION Improvements in technology and techniques, advancements in intraoperative confirmation and postoperative surveillance, studies that assist risk stratification, and expert consensus evaluations will help guide surgeons in their decision for addressing misplaced screws.

Database study.The purpose of this study was to use a large, nationwide database to determine prevalence of pediatric spine fractures in the United States, associated injuries, mechanisms of injury (MOI), use of safety devices, and mortality rates.Spinal fractures account for 1% to 2% of pediatric injuries. However, they are associated with significant comorbidities and complications. Motor vehicle accidents (MVAs) are most responsible for increased incidence observed.Retrospective review of National Trauma Data Bank between 2009 and 2014 (analysis in 2019) for all vertebral fractures in patients under 18 years of age. Subanalysis included those in MVAs where protective device use data were available. Patient demographics, MOI, geographical and anatomical region of injury, concomitant musculoskeletal/organ injury, protective device usage, hospital length of stay, surgical procedures, and mortality were all analyzed.A total of 34,563 patients with 45,430 fractured vertebrae included. Median age was 15 years. Most fractures (63.1%) occurred in patients aged 15 to 17 years, most frequent MOI was MVA (66.8%), and most common geographic location was the South (38%). Males sustained more spine fractures than females, overall (58.4% vs. 41.6%; P 0.001) and in MVAs (54.4% vs. 45.6%; P 0.001). Those in MVAs wearing seatbelts had lower odds of cranial (29.6% vs. 70.4%; odds ratio [OR] = 0.85, 95% confidence interval [CI]: 0.82-0.89; P 0.001) and thoracic (30.1% vs. 69.9%; OR = 0.88, 95% CI: 0.84-0.91; P 0.001) organ injury, multivertebral (30% vs. 70%; OR = 0.78, 95% CI: 0.73-0.83; P 0.001) and concomitant nonvertebral fractures (30.9% vs. 69.1%; OR = 0.89, 95% CI:0.73-0.83; P 0.001), and 21% lower odds of mortality (29.3% vs. 70.7%; OR = 0.79, 95% CI: 0.66-0.94; P = 0.009). Over 70% of drivers were not restrained during MVA, with majority of seatbelt violations incurred by males, ages 15 to 17, in the South.Over 60% of pediatric spinal fractures occur in children aged 15 to 17 years, coinciding with the beginning of legal driving. MVA is the most common cause and has significant association with morbidity/mortality. Nearly two- thirds pediatric spinal fractures sustained in MVAs occurred without seatbelts. Absence of seatbelts associated with20% greater odds of mortality. Ensuring new drivers wear protective devices can greatly reduce morbidity/ mortality associated with MVA.Level of Evidence: 3.

Single-center retrospective chart review with minimum 2-year follow up.To determine incidence of pulmonary hypertension in adolescent idiopathic scoliosis patients and to determine the effect of scoliosis surgery on pulmonary hypertension.Spinal deformity in adolescent idiopathic scoliosis can increase right atrial and ventricular pressures secondary to restrictive lung disease. Pulmonary hypertension leading to cor pulmonale is the most feared outcome, however mild pulmonary hypertension in adolescent idiopathic scoliosis (AIS) patients has been reported. No study has previously examined changes in the improvement of right heart function following scoliosis surgery.Cobb angle, 2D-echo signs of structural heart disease, aortic root dimensions, tricuspid regurgitant jet velocity (TRV), pulmonary function tests (PFTs), arterial blood gas (ABG), and patient demographics reviewed. Right ventricular systolic pressure (RVSP) estimated using Bernoulli equation (4[TRV]2) and right atrial pressure. RVSP ≥36 mmHg is a surrogate marker for pulmonary hypertension. All echocardiograms were read by board certified Pediatric Cardiologists. Logistic regression used to assess for differences in TRV between groups.Mean preoperative RVSP was significantly elevated in AIS patients (26.9 ± 0.49; P 0.001) compared with controls (17.25 + 0.88). Only 47 (21%) Group 1 patients had elevated preoperative TRV (≥2.8 m/s) versus none in Group 2 (P 0.001). Additionally, logistic regression showed AIS patients have odds ratio of 3.29 for elevated TRV (P = 0.007)-an indirect measure of pulmonary hypertension. In all Group 3 patients, the cardiac function normalized postoperatively (mean TRV = 2.09 + 0.23; P 0.001). No association found between Cobb angle, aortic root parameters, or pulmonary function tests.This study found 13.9% of patients with adolescent idiopathic scoliosis had elevated TRV while controls had no TRV abnormalities. Additionally, RVSP measurements demonstrated mild pulmonary hypertension in AIS patients. These abnormal values normalized postoperatively, indicating the benefits of scoliosis surgery on cardiac function in adolescent idiopathic scoliosis.Level of Evidence: 3.

STUDY DESIGN A retrospective chart review of prospectively collected data. OBJECTIVE The aim of this study was to determine whether back-to-back scoliosis surgeries can be performed safely without compromising outcomes and the reproducibility of the practice between institutions. SUMMARY OF BACKGROUND DATA During the summer, spinal surgeons will often book multiple cases in one day. The complexity and demands of spinal fusion surgery call into question the safety. Change of operating room staff including anesthesiologists, nurses, and neurologists may introduce new risks. METHODS From 2009 to 2018, index AIS surgeries were included. In Groups 1, 2, and 3, surgeries were performed by a single surgeon. In Group 4, they were performed by other institutional surgeons. Group 1: first surgery of the day, Group 2: second surgery of the day, Group 3: only surgery of the day, Group 4: only surgery of the day by different institutional surgeon. Additional analysis was done to determine reproducibility after a surgeon was moved from Institution 1 to Institution 2. RESULTS Five hundred sixty-seven AIS patients were analyzed. Group 1 patients had similar radiographic outcomes compared with Group 2 (P > 0.05). Surgical time was similar (P = 0.51), but significantly more levels fused (P = 0.01). Compared with Group 3, Group 2 had a smaller preoperative Cobb (P = 0.02), shorter surgeries (P

Retrospective review.The objective of this study was to report on one institution's use of single bolus micro-dose intrathecal morphine as part of a rapid recovery pathway during posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) and its comparison to patients whose pain was controlled with patient-controlled analgesia (PCA).Narcotic substance addiction has risen across all patient populations, including pediatrics. Narcotics have been historically used in complex spine surgeries as a measure of pain control, predominantly provided as PCA and additional take-home medication.AIS patients undergoing PSF from 2015 to 2019 were reviewed. In 2018, we instituted a standardized rapid recovery pathway for scoliosis patients undergoing PSF utilizing micro-dose intrathecal morphine (ITM-RRP). Before this, traditional protocol with PCA was used for postoperative management. Perioperative data, morphine consumption and prescription refill requests were compared.There were 373 AIS patients total in this study, of which 250 patients were in the PCA group and 123 in the ITM-RRP Group. Preoperative Cobb angles (P = 0.195), as well as levels fused (P = 0.481) and body mass index (P = 0.075) were similar. 69.4% of ITM-RRP patients had a length of stay ≤3 days, significantly11.6% of PCA patients (P 0.001). ITM-RRP patients began ambulating significantly earlier with 84.6% patients out of bed by postoperative day 1 versus 8% PCA patients (P 0.001). Additionally, ITM-RRP patients had significantly lower VAS pain scores with activity and earlier initial bowel movements (P 0.001).Postoperative emesis was similar (P = 0.11). No patients had pruritus, respiratory depression, or required supplemental oxygenation.This is the first study to show that a rapid recovery protocol utilizing single micro-dose ITM with oral analgesics have adequate recovery, significantly better postoperative pain control and superior perioperative outcomes to traditional protocols using PCA in the AIS population following PSF.Level of Evidence: 3.

Multicenter retrospective review.This study aims to address major postoperative complications associated with Scheuermann kyphosis (SK) when compared with adolescent idiopathic scoliosis (AIS) in a large population matched by demographic characteristics, levels fused and operative technique.Prior studies have found that SK patients are 3.86 times more likely to experience major postoperative complications than in AIS. Historically, however, these studies have often had populations that were significantly different between the two groups in terms of disease severity, demographics, and small sample sizes.AIS patients were compared to SK patients between 2006 and 2018 contemporaneously. All surgeries were conducted by six surgeons among two institutions. Complications and revisions were calculated. A sub-analysis comparing SK and AIS patients by age, sex, and levels-fused in one-to-one matched pairs was performed as well as a sub-analysis matched by levels fused only in one-to-one matched pairs.One thousand three hundred twenty two patients were reviewed (1222 AIS; 100 SK). There were 52 (4.3%) complications in the AIS group compared with 20 (20%) complications in the SK group (P 0.001), with infections and revisions consisting of the majority of complication rates in both cohorts.When matched by age, sex, and levels fused, there were eight complications in the AIS group and 11 in the SK group (P = 0.63), with infection and revision rates being similar, (P = 0.29) and (P = 0.26) respectively.When matched by levels fused only, EBL, operative time and complication rates remained similar (P 0.05).Contrary to previously published literature, our analyses indicate that in a matched population, postoperative complication rates (i.e., infection and revision rates) are not significantly different between SK and AIS patients.Level of Evidence: 4.

STUDY DESIGN Retrospective review of prospective case-control study. OBJECTIVE To compare minimally invasive scoliosis surgery (MIS) and posterior spinal fusion (PSF) in a large group of patients. SUMMARY OF BACKGROUND DATA MIS, has been shown to have benefits over standard PSF in adolescent idiopathic scoliosis (AIS). METHODS Radiographic, clinical, and operative review of a multi-institutional prospective database from 2013 to 2018. MIS patients with minimum 2-year XR follow up were compared with open PSF technique patients. RESULTS Four hundred eighty five patients were included; 192 MIS and 293 PSF. Preoperative Cobb (P = 0.231) and kyphosis were similar (P = 0.501). Cobb correction was comparable (P = 0.46), however percent improvement in thoracic kyphosis was significantly higher in MIS (P

The objective of this study is to report operative time and associated complications of six types of implants and to determine if surgeons are adequately compensated. Hardware removals were analyzed from 2014-2019. Implants were flexible nails, intramedullary rigid nails, long plates, screw(s), single guided-growth plates, and multiple guided-growth plates. Patient demographics, operative time, blood loss, complications, and relative value units (RVU)/min were collected. RVU/min was used to maximize rate. In total, 392 patients were analyzed. Long plate removals took significantly longer than screw removal, therefore RVU/min was significantly lower (p0.001). Long plate removals also took significantly longer, and RVU/min was significantly lower compared to guided-growth plate removal (p0.001). Intramedullary nails took significantly longer compared to flexible nails, nearly double the RVU/min (p = 0.02). The results from this study indicate that the RVU/ minute for these six different types of implant removals are not equal. Surgeons can use this data to set up their schedule to ensure maximum utilization. (Journal of Surgical Orthopaedic Advances 30(1):020-023, 2021).

Standardized protocols in spine surgeries have been shown to increase patient safety and outcomes. Surgical correction of adolescent idiopathic scoliosis (AIS) is a high-risk procedure with potential complications including blood loss, long surgery duration, and neurological complications. Expedited recovery after surgery protocols and the perioperative surgical home are two initiatives that address the need for increased efficiency in patient care. In 2011, we implemented a standardized …

PS misplacement rate is reported between 6-15%. Studies looking at misplacements on a per patient basis show up to 14% of patients have screws at risk (impinging vital structures). A screw abutting the aorta is a management challenge and often requires vascular surgery intervention. However, CT scans routinely done in supine position may overestimate screw-aorta relationship. Change in patient position may allow the aorta to roll away and, in most cases, reveal …

Recent studies, with small sample size, suggest that improving thoracic kyphosis leads to better lumbar Cobb correction in selective thoracic fusion (STF). It is also believed that lumbar Cobb correction closely follows thoracic correction. The objective of this study is to evaluate the role of thoracic Cobb and kyphosis correction in lumbar correction in a larger group of patients. Retrospective chart and x-ray review of patients …

Studies have shown that narcotic substance addiction has been on a rise across all patient populations, including pediatrics. Narcotics have long been used in complex spine surgeries as a pain control method and are often given in the form of patient controlled analgesia (PCA) during postoperative recovery and take home medication. The objective of this study was to report on one institution’s use of single bolus micro-dose intrathecal morphine (ITM) during Posterior Spinal Fusion (PSF) for Adolescent Idiopathic Scoliosis (AIS) and its comparison to patients whose pain was controlled with …

Spinal deformity in AIS can increase right atrial and ventricular pressures secondary to restrictive lung disease. Pulmonary hypertension leading to cor pulmonale is the most feared outcome, however mild pulmonary hypertension in AIS patients has been reported in the past. No study has examined these changes including the improvement of right heart function following scoliosis surgery. We hypothesize that scoliosis repair …

MIS in patients with idiopathic scoliosis is an innovative technique comparable to the standard open posterior approach. We seek to compare the two different approaches in case-control matched manner in the AIS population. 21 MIS patients were matched with 21 PSF controls based on age, Cobb …

Rett syndrome (RS) patients often present with scoliosis, which requires surgical correction and has been shown to increase survival rate. However, literature is limited and reports major surgical complications including respiratory failure, prolonged intubation, infections, significant blood loss, and prolonged hospital stay. Cerebral palsy (CP) patients undergoing scoliosis surgery may be comparable to RS patients. They are often nonverbal, nonambulatory …

BACKGROUND CONTEXT Pedicle screw insertion in scoliosis is challenging due to the 3-dimensional deformity and abnormal pedicle morphology. Free hand or fluoroscopic guidance is frequently utilized. Technological advancements have led to more adaptation of computer assisted screw insertion. These involve changing the technique from a ‘tactile feedback’ to ‘screen-based guidance’. While improvement in screw accuracy has been documented, an increase in surgical time with increased possibility of blood loss, and risk of infection can occur. Additionally, increased radiation exposure, especially with a subsequent second spin for confirmation after navigation is also a concern in pediatric population. PURPOSE This study aims to evaluate the surgical outcomes of a free hand screw insertion followed by intraop CT confirmation and compare to free hand with fluoroscopy and traditional computer assisted approaches. STUDY DESIGN/SETTING Retrospective review. PATIENT SAMPLE Retrospective chart review of 289 AIS patients between 2015 and 2020 from a single institution and 356 AIS from NSQIP 2012-2018 database undergoing posterior spinal fusion. OUTCOME MEASURES Radiographic outcomes and surgical outcomes including radiation dose, blood loss, operative time and 30-day complication rates. METHODS Part I: 152 patients were operated using the freehand technique ‘n’ AIRO technology approach (TNT group); 137 were operated using freehand anatomic and fluoroscopy (Fluoro Group). Radiographic measurements, and clinical outcomes including radiation dose, blood loss, operative time and 30-day complications were compared. Part II: 152 TNT patients were compared to 356 AIS patients from the NSQIP database that were operated on using computer-assisted navigation between 2012 and 2018 (Navigation Group). Operative time, blood loss and 30-day complications were compared. All data was presented as mean and frequencies where appropriate. Fisher's Exact and Kruskal-Wallis tests were used for statistical analysis. RESULTS Part I: Average radiation dose for TNT patients was 8.3 mGy compared to 3.5 mGy for the fluoro group (p CONCLUSIONS As novel technology allows for better anatomic bone visualization, surgeons should implement these innovations into their technique accordingly, while maintaining surgical control. This technique and technology approach allows for adopting technology into surgical approach rather than restructuring the surgical approach. This happy medium helps with screw accuracy without prolonging surgical time, blood loss and associated complications and has superior surgical outcomes compared to both traditional fluoroscopy and computer assisted approaches. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT When examined as a collective group, NMS has a worse prognosis and surgical outcomes than its AIS counterpart. However, not all operative patients with diagnoses of cerebral palsy, Duchenne muscular dystrophy or other NMS pathology necessarily suffer similar poor outcomes associated with the class. PURPOSE Our aim is to examine more mildly affected NMS patients to determine whether their surgical outcomes are comparable to AIS with regards to patient safety. STUDY DESIGN/SETTING Ambispective review PATIENT SAMPLE Radiograph and retrospective chart review of NMS and AIS patients undergoing PSF with pedicle screws from 2005-2018 were analyzed. OUTCOME MEASURES intraoperative parameters and radiographic measurements were collected at pre- and postoperatively. METHODS Group 1 included NMS patients who could ambulate without assistance (GMFCS I-III). Group 2 was AIS patients. Demographics, Wilcoxon rank sums tests and chi-square tests were performed. RESULTS Group 1 (n = 48) and Group 2 (n = 158) were similar in age, sex, preoperative kyphosis, pre- and postoperative Cobb angle, and Cobb correction. Additionally, EBL (p=0.143), postoperative transfusions (p=0.5), and perioperative complications within 30 days (p=0.5) were similar between groups. Infections (p = 0.592), DVT (p = 0.232), revisions (p = 1.0), and mortality (p = 1.0) were statistically similar. Group 2 NMS patients did have increased fusion levels (p CONCLUSIONS NMS inherently confers high risk of blood loss, longer surgeries and fusions, complications, ICU and hospitals stays. Our data confirms longer fusion levels, surgical time and hospital stay with lower extubation rates. Infection rate, revisions and overall complications were similar to AIS population as were the radiographic outcomes. This suggests that NMS patients who are ambulating can expect surgical outcomes quite comparable to AIS patients with further room for improvement in surgical duration and anesthesia protocols. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Cadaveric study. To establish the safety and efficacy of magnetically controlled growing rods (MCGRs) after magnetic resonance imaging (MRI) exposure. MCGRs are new and promising devices for the treatment of early-onset scoliosis (EOS). A significant percentage of EOS patients have concurrent spinal abnormalities that need to be monitored with MRI. There are major concerns of the MRI compatibility of MCGRs because of the reliance of the lengthening mechanism on strongly ferromagnetic actuators. Six fresh-frozen adult cadaveric torsos were used. After thawing, MRI was performed four times each: baseline, after implantation of T2–T3 thoracic rib hooks and L5–S1 pedicle screws, and twice after MCGR implantation. Dual MCGRs were implanted in varying configurations and connected at each end with cross connectors, creating a closed circuit to maximize MRI-induced heating. Temperature measurements and tissue biopsies were obtained to evaluate thermal injury. MCGRs were tested for changes to structural integrity and functionality. MRI images obtained before and after MCGR implantation were evaluated. Average temperatures increased incrementally by 1.1°C, 1.3°C, and 0.5°C after each subsequent scan, consistent with control site temperature increases of 1.1°C, 0.8°C, and 0.4°C. Greatest cumulative temperature change of +3.6°C was observed adjacent to the right-sided actuator, which is below the 6°C threshold cited in literature for clinically detectable thermal injury. Histologic analysis revealed no signs of heat-induced injury. All MCGR actuators continued to function properly according to the manufacturer’s specifications and maintained structural integrity. Significant imaging artifacts were observed, with the greatest amount when dual MCGRs were implanted in standard/offset configuration. We demonstrate minimal MRI-induced temperature change, no observable thermal tissue injury, preservation of MCGR-lengthening functionality, and no structural damage to MCGRs after multiple MRI scans. Expectedly, the ferromagnetic actuators produced substantial MR imaging artifacts. Level V.

BACKGROUND CONTEXT Neuromuscular scoliosis patients have a purportedly higher postoperative complication rate than those with adolescent idiopathic scoliosis. Of these, gastrointestinal (GI) issues are clinically well observed. However, there is limited data on the prevalence of postoperative GI complications, and the preoperative indicators that may predict them. PURPOSE The focus of this study is to determine the incidence and risk factors of gastrointestinal complications after neuromuscular scoliosis correction. STUDY DESIGN/SETTING Retrospective case review. PATIENT SAMPLE Inclusion criteria focused on pediatric scoliosis patients ( OUTCOME MEASURES Radiographic, clinical and hospital stay data was assessed. Patients were compared according to their postoperative gastrointestinal (GI) complication status. PO GI issues were described as either major or minor complications. Minor complications included continued nausea/vomiting, constipation, diarrhea and distention. Major complications included extended paralytic ileus, dysphagia, g-tube infections and gastroparesis based on literature and clinical experience. METHODS An IRB approved, retrospective case review of patient records from 2013 – 2019. Data was presented as median and interquartile values in order to avoid the effects of outsider values. Statistically, Fisher's Exact, Kruskal-Wallis and Chi-Squared tests were used. RESULTS We included a total of 69 patients, of which, 36 developed PO GI issues. Age and BMI values were similar for both groups of patients (p = 0.367, p = 0.371). Of the patients that developed PO GI complications, the overwhelming majority exhibited minor complications only (94.3%). PO GI patients had a significantly longer length of stay (9 vs 6 days, p = 0.004). While preoperative major Cobb angles were similar, patients that developed PO GI issues had a significantly higher preoperative pelvic obliquity (15.80 cm vs 7.55 cm, p = 0.040). Patients that developed PO GI issues were overwhelmingly classified with ASA scores of 3 or 4 (96.6%), were more likely to have a preoperative gastrostomy tube (p CONCLUSIONS Spasticity, the presence of a pre-existing GI issue, presence of a g-tube, and notable pelvic tilt appear to be significant risk factors for postoperative gastrointestinal complications in neuromuscular scoliosis patient. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Incidence of proximal junctional kyphosis (PJK) in Scheuermann's Kyphosis (SK) varies between 24–40%. Multiple factors have been implicated, including: overcorrection of kyphosis, failure to include the proximal end vertebra and choice of implants. Recently, studies have attempted to analyze pelvic parameters in SK, including lumbopelvic mismatch. However, the issue remains unresolved. PURPOSE This study aimed to determine the goal correction parameters based upon patients’ kyphosis, pelvic incidence, and UIV to prevent PJK in Scheuermann's Kyphosis. STUDY DESIGN/SETTING Retrospective Chart Review. PATIENT SAMPLE A total of 96 Sheuermann Kyphosis patients undergoing correction procedures with all pedicle screws (PS), hybrid fixation (HF) or anterior/posterior fusions with hybrid fixation (AP). OUTCOME MEASURES Kyphosis minus pelvic incidence > -10° was determined to be normal. T1/T2 were grouped together as proximal fusion group compared to T3 and distal group. METHODS X-ray and chart review of all SK patients analyzed and compared. RESULTS 96 total patients: PS (n=41), HF (n=24), and AP (n=31). Overall, at early postop 12/96 (12.5%) patients had PJK. At final follow-up 33/96 (34.4%) had PJK. There was no significant difference between groups at early postop (p = 0.86) or final follow-up (p = 0.67). When correcting Kyphosis-PI to > -10° and UIV was chosen to be T1 or T2, PJK developed in 6% of patients. When fusing to T1/T2 and having kyphosis-PI -10° but UIV chosen at T3 or below, 77.8% of patients developed PJK. When fusing to T3 or below and failing to correct kyphosis-PI to > -10°, 37% of patients developed PJK. CONCLUSIONS While surgical techniques and implants do not seem to have a substantial role in development of PJK, selecting proximal UIV and avoiding Kyphosis-PI mismatch can significantly decrease this possibility. Surgeons treating Scheuermann's Kyphosis should, therefore, aim to correct kyphosis closer to patient's pelvic incidence. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

MINI: The objective of this study was to evaluate the accuracy and reliability of pedicle screw placement using O-Arm at dosages below the manufactured recommended dose. O-Arm at reduced dose showed a 90% accuracy when compared with computed tomography; however, about 30% medial breaches were misclassified.Cadaveric study.The objective was to evaluate O-Arm's ability at low-dose (LD) settings to assess intraoperative screw placement.Accurate placement of pedicle screws is crucial because of proximity to vital structures. Malposition of screws may result in significant morbidity and potential mortality. O-arm provides real-time, intraoperative imaging of patient's anatomy and provides higher accuracy in scoliosis surgeries, avoiding risk to vital structures. We hypothesize using LD or ultra-low doses (ULDs) to obtain intraoperative images allow for accurate assessment of screw placement, both minimizing radiation exposure and preventing screw misplacement.Eight cadavers were instrumented with pedicle screws bilaterally from T1 to S1. Screws were randomly placed using O-arm navigation into three positions: contained within the bone, OUT-anterior/lateral, and OUT-medial. O-arm images were obtained at three dosage settings: LD (kVp120/mAs125-lowest manufacturer recommended), very-low dose (VLD) (kVp120/mAs63), and ULD (kVp120/mAs39). Computed tomography (CT) scan was performed using institution's LD protocol (kVp100/mAs50) and gross dissection to identify screw positions.LD, VLD, ULD, and CT for identifying "IN" screws relative to gross dissection had, a mean (standard deviation) sensitivity of 84.2% (±5.7), specificity of 76.1% (±9.3), and accuracy of 79.9% (±3.1) from all three observers. Across the three observers, the interobserver agreement was 0.67 (0.61-0.72) for LD, 0.74 (0.69-0.79) for VLD, 0.61 (0.56-0.66) for ULD, and 0.79 (0.74-0.84) for CT. Effective doses of radiation (mSV) for LD O-arm scan was 2.16, VLD 1.08, ULD 0.68, and our LD CT protocol was 1.05.Accuracy of pedicle screw placement is similar for O-arm at all doses and CT compared to gross dissection. Interobserver reliability was substantial for VLD and CT. Approximately 30% of medial screw breaches are, however, misclassified. ULD and VLDs can be used for intraoperative navigation and evaluation purposes within these limitations.N/A.

BACKGROUND CONTEXT Increased surgical volume has been associated with improved perioperative outcomes after spinal deformity correction. However, there is a lack of information on how this may affect hospital costs. PURPOSE To determine whether high volume surgeons have lower costs than low-volume surgeons in spinal deformity surgery. STUDY DESIGN/SETTING Retrospective review. PATIENT SAMPLE This study included 335 AIS patients. OUTCOME MEASURES Age, BMI, Cobb, kyphosis, surgical time, anesthesia time, transfusion, blood products, overall hospital costs, extubation rate, return to ED. METHODS A retrospective study of adolescent idiopathic scoliosis (AIS) patients undergoing PSF from 2013 – 2019 was performed. Demographic, XR, chart review and hospital costs were collected and compared between high-volume (HV) surgeons (>50 AIS cases/yr) and low-volume (LV) surgeons (≤50/yr). Comparative analyses were computed using Wilcoxon Rank-Sum, Kruskal-Wallis, and Fisher's exact tests. Median values with corresponding IQRs were reported. RESULTS A total of 335 patients (HV: 198, LV: 137) operated by 4 surgeons (1 HV, 3 LV). Radiographic parameters were similar between the groups. HV surgeons had significantly lower EBL (325v600 mL, p CONCLUSIONS High volume surgeons had lower transfusion rates, shorter surgery time and were more likely to be extubated in the OR than their low volume counterparts. In addition, high volume surgeons had lower overall costs compared to low volume surgeons. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Studies have shown that narcotic substance addiction has been on a rise across all patient populations, including pediatrics. Narcotics have long been used in complex spine surgeries as a measure of pain control, and are often given in the form of patient-controlled analgesia (PCA) during postoperative recovery as well as take-home medication. PURPOSE The objective of this study was to report on one institution's use of single bolus microdose intrathecal morphine (ITM) during PSF for AIS and its comparison to patients whose pain was controlled with PCA. STUDY DESIGN/SETTING Retrospective review. PATIENT SAMPLE AIS patients undergoing PSF from 2011–2019 were reviewed. PCA patients were included in Group 1 and ITM in Group 2. OUTCOME MEASURES Intraoperative clinical data (operative time, estimated blood loss), postoperative hospital stay course, request for prescription refill, morphine equivalence. METHODS In 2018, we instituted an RRP for scoliosis patients undergoing PSF utilizing intrathecal micro dose ITM. Previously, PCA was the mainstay for postop pain management. In the ITM protocol, patients receive 1.5 mcg/kg ITM diluted in 1 cc saline administered preoperatively by anesthesiologists or intraoperatively by the surgeon. Postoperatively, patients received IV ketorolac at 0.5mg/kg Q6h, PO Tylenol (15 mg/kg q6h), PO oxycodone (0.1 mg/kg q4), and IV hydromorphone (15 mcg/kg) for breakthrough pain. At discharge, PCA patients received 14-day prescriptions for 5mg oxycodone q6 compared to just 7-day prescriptions in the ITM group. Charts from 2011 – 2019 were reviewed. PCA patients were included in Group 1 and ITM in Group 2. Periop data and patient requests for prescription refills were analyzed and compared using Kruskal-Wallis and chi-squared tests. RESULTS A total of 340 patients (PCA: 215; ITM:125). Levels fused (p = 0.325) and BMI (p = 0.746) were similar. Patients in Group 1 had a significantly higher median length of stay (p CONCLUSIONS This is the first study showing that use of microdose ITM with oral analgesics have significantly better postoperative pain control and perioperative outcomes to PCA in the AIS population following PSF. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Hemivertebra excision in patients with congenital scoliosis is believed to give the best possible correction. It is, however, a technically challenging procedure and complications can include spinal cord injury, nerve root injury and CSF leak. We have utilized a hemivertebra-sparing approach in these patients alongside multi-level Ponte osteotomies and all pedicle screw constructs. PURPOSE To determine if this approach leads to similar perioperative correction and radiographic outcomes to AIS patients. STUDY DESIGN/SETTING A retrospective case-controlled matched study. PATIENT SAMPLE Twenty-four patients with congenital scoliosis and associated hemivertebra compared with the most recent 54 AIS correction surgeries with 2-year follow-up. OUTCOME MEASURES Curve correction, surgical time, blood loss, complications, length of stay, levels fused, fixation points. METHODS Twenty-four patients with congenital scoliosis and associated hemivertebra were included. These 24 patients were compared with the most recent 54 AIS correction surgeries with 2-year follow-up. An additional rigorous analysis was done to match hemivertebra patients from a database of 330 AIS patients. Patients were matched based on gender, age, BMI, and preop Cobb. Overall, 12 pairs (24 patients) were matched and analyzed. RESULTS When comparing hemivertebra to AIS patients, age (p=0.81), BMI (p=0.24) and preop Cobb (p=0.06) were similar. Postop Cobb (p=0.048) was significantly larger for AIS patients, however, overall Cobb correction was similar (p=0.29). Blood loss was similar (p=0.09) while surgical time (p CONCLUSIONS Patients with hemivertebra can benefit from hemivertebra sparing approach. The XR and periop outcomes were similar to AIS patients. This approach is safer compared to hemivertebra excision with similar or better curve correction than previously reported. Choosing fusion levels on similar principles akin to AIS leads to avoidance of hemivertebra excision in most cases including lumbosacral hemivertebra cases. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Non-ambulatory NMS patients are typically fused to the pelvis to augment fixation, prevent loss of correction and improve seating balance. However, pelvic fixation extends the length of surgery, increases EBL and may increase pain. PURPOSE This study aims to evaluate the radiographic outcomes after PSF with all pedicle screws in NMS fixated (FP) and not fixated at the pelvis (NFP). STUDY DESIGN/SETTING Retrospective and Prospective Review. PATIENT SAMPLE Ambulatory and non-ambulatory neuromuscular patients undergoing spinal deformity correction at one institution. OUTCOME MEASURES Preoperative and postoperative radiographic parameters and intraoperative clinical measures (estimated blood loss, operative time). METHODS Radiographic measurements, OR parameters and demographics were recorded for neuromuscular surgeries between 2006-2016. Patients were divided into NFP and FP. Median values and Wilcoxon rank sum tests were used. Subanalysis was performed for patients with preoperative PO 20°. RESULTS There were 91 patients; 63 were non-ambulatory. Between NFP (n=54) and FP (n=37), preop Cobb (p=0.215), PO (p=0.158), and decompensation (p=0.247) were similar. Both had similar final Cobb (p=0.146) and PO (p=0.162), but NFP had significant coronal imbalance (35.8 vs 14.6, p 20, patients had similar preop PO (p=0.545) and decompensation (p=0.075). NFP had higher final PO (p=0.123) and significantly higher decompensation (135.4 vs 25.2, p=0.008). The change in PO (p=0.298) and decompensation (p=0.616) from postop to final was similar. CONCLUSIONS NFP with preop PO>20 had significant coronal imbalance and PO at final follow-up. Change in PO and coronal balance over time was similar between the two groups in less severe PO. PF achieves better coronal and PO correction. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Study design Retrospective chart review. Objective To determine if obtaining a prone computed tomography (CT)-scan can better delineate a questionable screw-aorta relationship. Summary of background data Pedicle screw misplacement rate is reported between 6% and 15%. Studies looking at misplacements on a per patient basis show up to 14% of patients have screws at risk (impinging vital structures). A screw abutting the aorta is a management challenge and often requires vascular surgery intervention. However, CT scans routinely done in supine position may overestimate screw-aorta relationship. Change in patient position may allow the aorta to roll away and, in most cases, reveal an uncompromised aorta. This will allow safe removal of pedicle screws without any vascular intervention. Methods One hundred eleven spinal deformity patients who underwent Posterior spinal fusion from 2004 to 2009 were evaluated. Patients with concerning screw-aorta relationship underwent additional prone CT scan. Mobility of the aorta was determined and distance was compared using prone and supine CT scans. Results Two thousand two hundred ninety five screws were reviewed, 36 screws in 18 patients were in proximity to the aorta. Fourteen screws (nine patients) appeared to be impinging the aorta. On prone CT, 13 out of the 14 instances the aorta moved away from the screw. The average distance at the screw level was 13.6 ± 4.8 mm in supine position and 8.9 ± 5.4 mm in prone position (P = 0.001). In one instance the relationship was unchanged on prone CT. No screw was noted to violate the lumen or distort the aorta. Conclusion Supine CT scan alone is not entirely accurate in determining screw-aorta relationship. Prone-CT scan provides additional information for better delineation. This additional diagnostic step can change the treatment option by limiting the need for vascular intervention. When in doubt, the additional use of an arteriogram can allow for improved visualization. Level of evidence 3.

Study design Porcine model. Objective To quantify critical vascular and mechanical events that occur before and during an evolving spinal cord injury. Summary of background data Spinal cord injuries are one of the most devastating complications in spine surgery. Intraoperative neuromonitoring changes can occur as a secondary event of spinal cord compression and decrease in spinal cord blood flow (SCBF). Laser Doppler flowmetry has been well validated for measuring blood flow. Methods Seventeen pigs were studied, 14 of which completed the experiment. Multilevel, midthoracic laminectomies were performed. Laser Doppler flowmetry electrodes were placed on the dura to measure SCBF. Spinal cord injury was induced by incremental balloon inflation in the epidural space. The animals were separated into two groups. After motor-evoked potential (MEP) loss, group A underwent medical interventions and then balloon decompression approximately 20 minutes later. Group B underwent immediate balloon decompression followed by medical interventions. After interventions, wake-up test was performed and computed tomography scan measured thoracic spinal canal volume. Results Median SCBF changes were seen 15.8 (5.4-25.1) minutes before MEP loss. However, the 20% threshold interval was often reached before. At the 20% threshold, median pressure was 7 psi, balloon volume was 0.5 cm, and 50% of the spinal canal was compromised. In group A, no pigs moved and all had pathology indicating ischemia. In group B, 9 of 10 were found to be moving their hind legs with 7 indicating ischemia. Conclusion Compression spinal cord injury is the end of a cascade involving increasing intracanal pressure, decreasing canal volume, and hypoperfusion. Rapid relief of compression leads to MEP return. SCBF monitoring can detect ischemia preinjury, giving surgeons an opportunity for early intervention. Level of evidence 4.

Retrospective chart review of prospectively collected data. This study seeks to evaluate the effect of number of surgeons, surgeon experience, and surgeon volume on AIS surgery. Recent literature suggests that utilizing two surgeons for spine deformity correction surgery can improve perioperative outcomes. However, the surgeon’s experience and surgical volume are likely as important. AIS patients undergoing PSF from 2009 to 2019 were included. Patient demographics, X-ray and perioperative outcomes were collected and collated based on primary surgeon. Analysis was performed for single versus dual surgeons, surgeon experience (≤ 10 years in practice), and surgical volume (less/greater than 50 cases/year). Median (IQR) values, Wilcoxon Rank Sums test, Kruskal–Wallis test, and Fisher’s exact test were utilized. 519 AIS cases, performed by 4 surgeons were included. Two surgeons were highly experienced, 1 of whom was also high volume. Five cohorts were studied: a single senior high volume (S1) (n = 302), dual-junior surgeons (DJ) (n = 73), dual senior–junior (SJ) (n = 36), dual-senior (DS) (n = 21) and a single senior, standard-volume surgeon alone (S2) (n = 87). Radiographic parameters were similar between the groups (p > 0.05). Preoperative Cobb was significantly higher for DS compared to S1 (p = 0.034) Pre- and post-op kyphosis were similar (p > 0.05). Cobb correction was similar (p > 0.05). Levels fused, fixation points, anesthesia and surgical times were similar (p > 0.05). When the standard-volume surgeon operated with a second surgeon, radiographic parameters were similar (p > 0.05), but anesthesia time, surgical time, and hospital length of stay were significantly shorter (p

Minimally invasive scoliosis surgery (MIS), in smaller studies, has been shown to have significant benefits over standard posterior spinal fusion (PSF) in adolescent idiopathic scoliosis (AIS). This study seeks to compare the two procedures in a large group of patients. Retrospective review of a multi-institutional prospective database was performed. …

Retrospective review of magnetic resonance imaging (MRI) and computed tomographic (CT) scan imaging modalities.To determine MRI's capability of identifying pedicle morphology.Understanding pedicle morphology is important for accurate placement of pedicle screws. The gold standard modality to assess pedicle morphology is CT scan. However, CT scans carry the risk of radiation exposure. We have studied MRI as a potential alternative to CT scan.Nine hundred seventy pedicles in 33 spinal deformity patients were reviewed. Pedicle morphology was classified as follows: Type A (normal pedicle):4-mm cancellous channel; Type B: 2-4-mm channel; Type C: any size cortical channel; and Type D:2-mm cortical or cancellous channel. Pedicles in the same patients were classified on both low-dose CT scan and MRI. Concordance and discordance rates of MRI relative to CT scan in classification of pedicles into types A, B, C, and D were calculated for the entire length of the thoracolumbar spine and subgrouped into spinal sections. All images were evaluated by a single fellowship-trained musculoskeletal radiologist.CT scan had 809 Type A, 126 Type B, 29 Type C, and 6 Type D pedicles. Group II (MRI) had 735 Type A, 203 Type B, 30 Type C, and 2 Type D pedicles. Analysis of the entire spinal column showed a concordance rate of 86.7% in classification of the pedicles into the 4 types. In the upper thoracic region, the concordance rate was 77.1%, main thoracic 85.5%, thoracolumbar 96%, and lumbar 98.1%. MRI has a poor overall accuracy for detecting Type C pedicles, only a 44.8% concordance with CT scan. MRI overcalls Type B pedicles, often calling Type A pedicles Type B.MRI is an inferior alternative to CT scan as it has poor accuracy to properly detect pedicle abnormalities. The more severe the pedicle abnormality, the less diagnostic value the MRI has.Level III, diagnostic.

Study design A retrospective review of charts, x-rays (XRs) and computed tomography (CT) scans was performed. Objective To evaluate the accuracy of pedicle screw placement using a novel classification system to determine potentially significant screw misplacement. Summary of background data The accuracy rate of pedicle screw (PS) placement varies from 85% to 95% in the literature. This demonstrates technical ability but does not represent the impact of screw misplacement on individual patients. This study quantifies the rate of screw misplacement on a per-patient basis to highlight its effect on potential morbidity. Methods A retrospective review of charts, XRs and low-dose CT scans of 127 patients who underwent spinal fusion with pedicle screws for spinal deformity was performed. Screws were divided into four categories: screws at risk (SAR), indeterminate misplacements (IMP), benign misplacements (BMP), accurately placed (AP). Results A total of 2724 screws were placed in 127 patients. A total of 2396 screws were placed accurately (87.96%). A total of 247 screws (9.07%) were BMP, 52 (1.91%) were IMP, and 29 (1.06%) were considered SAR. Per-patient analysis showed 23 (18.11%) of patients had all screws AP. Thirty-five (27.56%) had IMP and 18 (14.17%) had SAR. Risk factor analysis showed smaller Cobb angles increased likelihood of all screws being AP. Sub-analysis of adolescent idiopathic scoliotic patients showed no curve or patient characteristic that correlated with IMP or SAR. Over 40% of patients had screws with either some/major concern. Conclusion Overall reported screw misplacement is low, but it does not reflect the potential impact on patient morbidity. Per-patient analysis reveals more concerning numbers toward screw misplacement. With increasing pedicle screw usage, the number of patients with misplaced screws will likely increase proportionally. Better strategies need to be devised for evaluation of screw placement, including establishment of a national database of deformity surgery, use of intra-operative image guidance, and reevaluation of postoperative low-dose CT imaging. Level of evidence 3.

BACKGROUND CONTEXT Posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) is a complex procedure for which charges can exceed $150,000. Among the total costs, inpatient and intensive unit care contributed 22%. Many institutions have implemented rapid recovery pathways (RRP) to improve patient care following scoliosis surgery. This study aims to determine the effects of a multimodal RRP, utilizing intrathecal morphine (ITM) in combination with oral pain medication, on hospital costs and patient management. PURPOSE The purpose of this study was to determine whether a protocol that excludes postoperative patient care analgesia (PCA) with the utilization of preoperative/intraoperative ITM had similar or superior outcomes, including hospital costs. STUDY DESIGN/SETTING Retrospective review. PATIENT SAMPLE AIS patients undergoing PSF from 2013 – 2019. OUTCOME MEASURES Hospital stay data, requests for opioid refill and overall costs. METHODS AIS patients undergoing PSF from 2013 – 2019 were retrospectively reviewed. RRP patients received ITM as part of their multimodal analgesia. Fusion level-matched control patients received hydromorphone PCA for postoperative pain management. At discharge, PCA patients received 14-day prescriptions for oxycodone compared to 7-day prescriptions in the ITM group. Perioperative data, requests for opioid refill, and overall costs were analyzed. RESULTS A total of 363 patients were included (PCA: 255, RRP/ITM: 108). BMI (p=0.786) and preoperative Cobb (p=0.343) were similar. RRP patients had a significantly shorter length of stay (3 vs 5 days, p CONCLUSIONS With increasing concerns about opioid dependence and hospital costs, our RRP pathway, which incorporates microdose ITM injections, allows for optimum perioperative management, improved costs, with overall better outcomes than the traditional PCA. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Rett syndrome (RS) patients often present with scoliosis, which requires surgical correction. However, literature is limited and reports major surgical complications including respiratory failure, prolonged intubation, infections, significant blood loss, and prolonged hospital stay. Cerebral palsy (CP) patients undergoing scoliosis surgery may be comparable to RS patients. They are often nonverbal, nonambulatory with frequent respiratory and surgical complications. Most surgeons have comparatively more experience treating CP patients than RS. PURPOSE The objective of this study is to compare perioperative outcomes of RS and CP patients. STUDY DESIGN/SETTING Retrospective review. PATIENT SAMPLE A total of 27 RS and 78 CP patients undergoing PSF from 2005-2018. OUTCOME MEASURES Cobb, kyphosis, pelvic obliquity, coronal decompensation, extubation rate, complication rate, EBL, surgical time, anesthesia time, levels fused, fixation points, METHODS Patient demographics, perioperative parameters, and X-ray measurements were collected at pre, post, and follow-up. Furthermore, a subanalysis was performed comparing the nonambulatory patients. Wilcoxon rank sums test and chi-square tests were utilized. RESULTS No significant difference for preop Cobb angle (p=0.16), kyphosis (p=0.20), and pelvic obliquity (p=0.09). No significant difference for fixation points (p=0.42), levels fused (p=0.79), time to extubation (p=0.53), complication rate (p=0.66), length of ICU (p=0.07) or hospital stay (p=0.71). EBL was significantly higher in CP patients (p=0.006) as was duration of anesthesia (p=0.04), and transfusion volume (p=0.01). However, surgical time (p=0.07) was similar. Postop Cobb (p=0.008) was significantly higher for CP, but kyphosis (p=0.18) and pelvic obliquity (p=0.09) were similar. Significant difference was found between both preop (p=0.02) and postop (p=0.03) coronal decompensation. Subanalysis of nonambulatory Rett and CP patients showed no significant difference in outcomes. CONCLUSIONS RS patients are comparable to CP patients in terms of surgical, periop, and radiographic outcomes. CP patients had significantly more EBL, intraop transfusions, and longer anesthesia time. The subjects did not differ in their ICU or hospital stays, nor their complication rate. Outcomes and periop expectations of RS patients are similar to CP. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

STUDY DESIGN Retrospective Chart and CT Scan Review. OBJECTIVE To define the relationship of the pre-vertebral structures for each level to assist in easier intraoperative visualization. SUMMARY OF BACKGROUND DATA Vascular and visceral injuries from pedicle screws are well-known. This study will define the relationship of the pre-vertebral structures for each level to assist in avoiding potential complications. METHODS Pre- and post-operative CT scans were reviewed to define the pre-vertebral structures in relation to a clock-face. On reformatted axial slices, a clock-face was superimposed so that the left transverse process (TP) represented 8 o'clock and the right TP represented 4 o'clock. The positions of the TP on the clock-face did not change with rotation of the vertebra. RESULTS 108 patients had pre-operative CT scans. 78 had post-operative CT scans. Median age was 15 years, median Cobb angle was 50°, fused were 12, with 21 fixation points. 6324 axial CT slices were reformatted and analyzed. The trachea was located at 12 o'clock at T1, 1 o'clock at T2-T4, and between 12 and 1 o'clock at T5. The esophagus starts as a midline structure at 12 o'clock from T1-T2, moves to 11 o'clock from T3-T6, and further to 10 o'clock from T7-T9. The aorta starts at 10 o'clock at T5-T6, moves left at T7-T8 to 9 o'clock, and returns to 10 o'clock from T9-T11. It appears at 11'clock at T12, and at 12 o'clock from L1-L4. In about a third of cases, it is at 1 o'clock from L1 to L4, where it bifurcates. CONCLUSIONS This CT-based anatomical study provides a simple reference frame to help surgeons visualize the vital structures at each level. This three-dimensional visualization is facilitated by fixing the position of TP on the clock-face. Knowledge of this anatomical relationship can help avoid direct injury, and is easier to recall intra-operatively. LEVEL OF EVIDENCE 3.

Purpose To report a case of motor evoked potential changes and spinal cord injury during the initial dissection in scoliosis surgery. Methods Motor evoked potentials to transcranial electrical stimulation were recorded from multiple muscles. Somatosensory evoked potentials to limb nerve stimulation were recorded from the scalp. Results Clear motor evoked potentials were initially present in all monitored muscles. The patient was then pharmacologically paralyzed for the initial dissection. More than usual bleeding was encountered during that dissection, prompting transfusion. As the neuromuscular blockade subsided, motor evoked potentials persisted in the hand muscles but disappeared and remained absent in all monitored leg muscles. The spine had not been instrumented. A wake-up test demonstrated paraplegia; the surgery was aborted. There were no adverse somatosensory evoked potential changes. MRI showed an anterior spinal cord infarct. Conclusions Copious soft tissue bleeding during the initial dissection might have lowered pressures in critical segmental arteries enough to cause spinal cord infarction through a steal phenomenon. The lack of somatosensory evoked potential changes reflected sparing of the dorsal columns. When neuromuscular blockade is used during the initial soft tissue dissection, motor evoked potentials should be assessed after this, but before spinal instrumentation, to determine whether there had been any spinal cord compromise during the initial dissection.

STUDY DESIGN A retrospective study. OBJECTIVE To determine the incidence of pedicle screws close to vital structures and to identify patient or curve characteristics that increase the risk of screw misplacement. SUMMARY AND BACKGROUND Most pedicle screw misplacements are asymptomatic, thus they are frequently undetected. This study identifies the rate of screw placement in proximity to vital structures using postoperative computed tomography scans. METHODS A total of 2132 screws in 101 patients, who underwent posterior spinal fusion for spinal deformity, were reviewed. Screws adjacent to great vessels and viscera were identified and evaluated. Patients with screws at risk (group B) were compared with patients without screws at risk (group A). Patient and curve characteristics were analyzed to determine whether a correlation with screw misplacement exists. RESULTS A total of 40 at risk screws (∼2%) were identified in 25 patients (∼25%). These 40 screws were in proximity to the aorta (31), left subclavian artery (1), esophagus (3), trachea (3), pleura (1), and diaphragm (1). Of the 31 screws close to the aorta, 10 screws in 6 patients were impinging or distorting the aortic wall. One hundred percent of misplaced screws were in the thoracic spine, 50% were misplaced laterally, 50% were 35 mm long, 57.5% were in pedicles with normal morphology, and 75% were in curves between 40 and 70 degrees. Median screw misplacement rate was 10% in group A and 13% in group B. Adjusted for age and preoperative Cobb angle, patients with a higher misplacement rate were more likely to have screws adjacent to vital organs [adjusted odds ratio: 1.06 (95% confidence interval, 1.01-1.13), P=0.033]. CONCLUSIONS Although only a small number of screws were at risk, they occurred in a large percentage of patients (25%). A single at-risk screw causes a significant complication for the patient. Postoperative imaging beyond routine x-rays may be needed to detect at-risk screws in asymptomatic patients.

BACKGROUND CONTEXT Spinal fractures account for only 2% to 3% of pediatric injuries. However, they're associated significant comorbidities and complications. PURPOSE This population-based study seeks to determine associated injuries and use of safety devices in pediatric spinal fractures. STUDY DESIGN/SETTING NTDB study. PATIENT SAMPLE A total of 6,008 pediatric patients. OUTCOME MEASURES Mechanism of injury, associated injuries, length of stay, neurological compromise. METHODS Pediatric spinal fractures were gathered from the National Trauma Data Bank for 2012. Data was found using ICD-9 805.xx or 806.xx, external cause of injury and procedure codes frequency, and median analyses were performed. RESULTS A total of 6,008 unique patients presented with 7,732 fractured vertebrae. A total of 2,179 (28.1%) cervical vertebrae, 2,151 (27.8%) lumbar, 2,052 (26.5%) involved the thoracic vertebrae, and the remainder involved sacro-coccyx. A total of 3,482 were male and 2,523 female; 4.2% of patients had an associated spinal cord injury. The most common associated musculoskeletal injury was femur fracture (6.7%), the most common associated organ injury was a lung contusion (4.6%) and 980 (16.3%) patients had associated skull fractures. A total of 15,285 fractures occurred in this patient population. Of the total vertebrae involved, 2,825 (31.7%) were repaired surgically. A total of 164 (2.7%) patients died from complications. A total of 2,708 (45.1%) patients were injured as an occupant of a motor vehicle accident (MVA); 25.8% were the drivers of the motor vehicle and 965 (35.7%) of these did not have a protective device present at the time of injury. More than half, 52.4%, of MVA patients were female. The median age of patients in MVA was 15 years (13-17). Interestingly, 48.9% of these were 16 or 17 years of age; the legal age of driving. Seventy-five (2.8%) of MVA patients died from complications. CONCLUSIONS MVA are the most frequent cause of spinal fractures in pediatric patients. Based on the numbers in this study, this amounts to 7.4 patients who present to ER daily with spine fractures from MVA. Approximately a third of these fractures occurred in patients without a protective device present. Nearly half of these fractures occur in children 16 or 17 years of age, the age when children become legally allowed to operate a motor vehicle. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT PS misplacement rate is reported between 6-15%. Studies looking at misplacements on a per patient basis show up to 14% of patients have screws at risk (impinging vital structures). A screw abutting the aorta is a management challenge and often requires vascular surgery intervention. However, CT scans routinely done in supine position may overestimate screw-aorta relationship. Change in patient position may allow the aorta to roll away and, in most cases, reveal an uncompromised aorta. This will allow safe removal of pedicle screws without any vascular intervention. PURPOSE To assess whether prone CT helps delineate the aorta-pedicle screw relationship. STUDY DESIGN/SETTING Retrospective chart review. PATIENT SAMPLE A total of 111 patients with post-op CT, who underwent PSF for spinal deformity, from 2004-2009. OUTCOME MEASURES Distance of pedicle screw from posterior margin of Aorta. METHODS A total of 111 patients with post-op CT, who underwent PSF for spinal deformity, from 2004-2009, were evaluated. Patients with concerning screw-aorta relationship underwent a prone CT scan. Mobility of the aorta was determined by measuring between a line drawn from the posterior margin of the aorta, perpendicular to the long axis of the screw, and a parallel line passing through the anterior margin of the body of the vertebra (in mm). This distance was compared using prone and supine CT scans. Paired t-test and signed rank tests were utilized. RESULTS There were 2,295 screws were reviewed, 45 screws in 27 patients were in proximity to the aorta. Thirty-six of these were in close proximity, but not impinging (>1cm aorta-screw distance). Fourteen screws (7 patients) were impinging ( CONCLUSIONS Supine CT-scan alone is not entirely accurate in determining screw-aorta relationship. Prone-CT scan provides additional information for better delineation. This additional diagnostic step can change the treatment option by limiting the need for vascular intervention. When in doubt, the additional use of an arteriogram can allow for improved visualization. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

BACKGROUND CONTEXT Return to the ED continues to be a quality measure in health care. The purpose of this study was to describe one institution's experience with visits to the ED following spinal deformity surgery. There were 11.8% of patients returned to ED within 90 days mostly with medical complaints – more than half by 30 days. There were no risk factors identified, however, a majority of complaints appear to be preventable. PURPOSE Return to the hospital after surgery is frequently being used as a quality metric. The purpose of this study is to evaluate the reasons and risk factors for ED visits less than 90 days. STUDY DESIGN/SETTING Ambispective chart review. PATIENT SAMPLE A total of 346 patients were included: 274 idiopathic scoliosis, 48 neuromuscular, 10 Scheurmann's kyphosis, 3 spondylolisthesis (grade 4), and 11 other. OUTCOME MEASURES Return to ED with medical-related complaints, return to ED with surgical-related complaints, age, BMI, preoperative kyphosis, levels fused. METHODS A review of spinal deformity surgeries between 2011-2018 was performed. Radiographic, operative and hospital stay data was collected. Median and interquartile range (IQR) was with Wilcoxon-Signed Rank and Kruskal-Wallis tests. Patients who returned to the ED for any reason within 90 days were analyzed. ED visits were categorized as medical and surgical. Medical visits included but not limited to fever, pain, and seizures. Surgical visits included but not limited to wound infection, and surgical site infection. RESULTS A total of 346 patients were included: 274 idiopathic scoliosis, 48 neuromuscular, 10 Scheurmann's kyphosis, 3 spondylolisthesis (grade 4) and 11 other. Forty-one patients (11.8%) returned to the ED within 90 days; 32 (78%) returned with medical-related complaints: pain (n=14), fever (n=6), constipation (n=4), spasm/seizures(n=2), syncope (n=3), fall (n=1) and dysnea (n=2). Nine patients (22%) returned with surgical-related complaints: drainage from incision (n=6), wound infection (n=2), and baclofen pump failure (n=1); 65.8% (n=27) returned to the ED within 30 days. There was no significant difference in age (13.19 vs 12.42 years, p=0.27), BMI (18.27 vs 17.13, p=0.33) preoperative Cobb (47.30 vs 46.0, p=0.731), preoperative kyphosis (16 vs 17, p=0.971), and levels fused (10 vs 11,=0.359) between those did not return to the ED and those who did. Blood loss (300 vs 350ml,p=0.973), surgical time (230 vs 228,p=0.180), and length of stay (4 vs 4, p=0.94) were also similar between the two cohorts. Neuromuscular distribution was also similar (12.8% vs 21.9%). CONCLUSIONS A total of 11.8% of patients returned to ED within 90 days, mostly with medical complaints – more than half by 30 days. Although no risk factors were found in this study, the findings present an opportunity to better improve discharge planning and care coordination. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.