Justin C. Paul

Greater operative volume is associated with lower complication rates in adolescent spinal deformity surgery.

Study Design. Retrospective analysis of prospectively collected data from the 2001 to 2010 Nationwide Inpatient Sample database. Objective. To assess complication rates in adolescent spinal deformity by surgeon operative volume for procedures with a range of complexity. Summary of Background Data. Surgeons performing higher volumes of lumbar spinal fusion have been associated with improved surgical outcomes, according to studies using the Nationwide Inpatient Sample. This relationship has not been shown in adolescent spinal deformity surgery. Methods. The Nationwide Inpatient Sample was queried for patients aged 10 to 18 years with in-hospital stays including spinal arthrodesis for scoliosis (adolescent idiopathic, neuromuscular, and congenital scoliosis). The primary end point was hospital stay morbidity: database-defined surgical, mechanical, major medical, and neurological complications. Length of stay and hospital charges were also analyzed. Annual surgeon volumes were stratified into quartiles based on number of cases (Q1: 1, Q2: 2–7, Q3: 8–19, and Q4: 20–97). To account for variation in surgical invasiveness, an operative complexity index was used. One-way analysis of variance was used to assess differences between quartiles for continuous measures and &khgr;2 for categorical measures. Results. A total of 6100 spine fusion cases met inclusion criteria for adolescent scoliosis. All complications categories were less frequent for higher volume surgeons after a primary fusion for all diagnoses. This pattern held for increasing surgical invasiveness, such as fusing 9 or more levels and became more distinct for neurological complications when comparing surgeons performing combined anterior-posterior procedures. Including all adolescent scoliosis fusions, higher surgical volume was associated with decreased length of stay and hospital charges. Conclusion. Perioperative complications after adolescent scoliosis fusion surgery are more frequent in lower volume settings. This may reflect a learning curve required for more complex cases as the trends are magnified in neuromuscular/congenital scoliosis cases or simply that higher volume surgeons are more adept at these fusions. The impact of volume on reduced length of stay and hospital charges has implications for future health care economics measures. Level of Evidence: 2

Use of Recombinant Bone Morphogenetic Protein Is Associated With Reduced Risk of Reoperation After Spine Fusion for Adult Spinal Deformity.

Study Design. Retrospective review. Objective. This study follows the inpatient-stay administrative data that were collected for a cohort of thousands of patients who had spine fusion surgery in the state of New York. We sought to examine adult spinal deformity (ASD) for reoperation events with and without the use of bone morphogenetic protein-2 (BMP). Summary of Background Data. Randomized controlled trials have suggested that BMP may increase the likelihood of solid arthrodesis in spinal surgery. This would imply fewer reoperations for pseudarthrosis, but small cohort sizes are inadequate to monitor these events. Methods. The 2008–2011 New York State Inpatient Database was queried using International Classification of Diseases, Ninth Revision, Clinical Modification codes. Patients age 21 years and older with a diagnosis of scoliosis and an index fusion of greater than 2 spinal motion segments were included. Patient identifiers and linkage variables were used to identify revisits. The relative risk of reoperation was calculated. The use of BMP at the initial inpatient stay was used to define the 2 cohorts for relative risk assessment. Results. A total of 3751 patients of ASD were identified in 2008. The use of BMP at the initial visit was performed at a rate of 37.6% for ASD. For posterior fusion cases longer than 8 levels, the rate of reoperation for a pseudarthrosis was 23.4%. For ASD fusions greater than 8 levels, the rate of reoperation for pseudarthrosis after using BMP at the index surgery was 5% and 33.9% when BMP was not used, a relative risk of 7.5 (P < 0.001). Conclusion. Using relevant inhospital patient records from the New York State Inpatient Sample, we found a 7.5-fold decrease in the risk of reoperation for pseudarthrosis after long fusions when using BMP. Decreased reoperation rates are caused by the improved fusion with the use of BMP. If subsequent unnecessary hospitals stays can be avoided, the economics of BMP use should be reexamined. Level of Evidence: 4

The Interobserver and Intraobserver Reliability of the Sanders Classification Versus the Risser Stage.

Background: Estimation of skeletal maturity, classically performed using Risser sign, plays a crucial role in the treatment of AIS. Recent data, however, has shown the simplified Tanner-Whitehouse (Sanders) classification, based on an anteriorposterior (AP) hand radiographs, to correlate more closely to the rapid growth phase and thus curve progression. This study evaluated the interobserver and intraobserver reliability of the Sanders and Risser classifications among clinicians at different levels of training. Methods: Twenty AP scoliosis radiographs and 20 AP hand radiographs were randomized and distributed to 11 graders. The graders consisted of 3 orthopaedic residents, 3 spine fellows, 3 spine surgeons, and 1 radiologist. The graders were then asked to classify the radiographs according to the Sanders and Risser classifications. There were 3 rounds of grading, each done 3 weeks apart. The overall &kgr; coefficient was then calculated for each system to evaluate the interobserver and intraobserver reliability. Results: For all graders the average &kgr; coefficient for the interobserver and intraobserver reliability of the Sanders classification was 0.54 and 0.62, respectively, and 0.46 and 0.49 for the Risser classification. With respect to spine attendings alone, the average &kgr; coefficient for the interobserver and intraobserver reliability of Sanders classification was 0.72 and 0.77, respectively, and 0.46 and 0.67 for the Risser classification. Conclusions: Our study demonstrated that the Sanders classification had moderate reliability with respect to physicians at various levels of training and had good reliability with respect to attending spine surgeons. Interestingly, the Risser staging was found to have less interobserver and intraobserver reliability overall. The Sanders classification is a reliable and reproducible system and should be in the armamentarium of surgeons who treat adolescent idiopathic scoliosis. Level of evidence: Level III.

Stability-preserving decompression in degenerative versus congenital spinal stenosis: demographic patterns and patient outcomes

BACKGROUND CONTEXT Although lumbar spinal stenosis often presents as a degenerative condition (degenerative stenosis [DS]), some patients present with symptoms from lifelong narrowing of the spinal canal. These patients have congenital stenosis (CS) and present with symptoms of stenosis at a younger age. Patients with CS often have a distinct pathophysiology with fewer degenerative changes but present with multilevel involvement. In the setting of neurologic symptoms, decompression alone while preserving stability has been proposed for both patient populations. PURPOSE The purpose of this study is to evaluate if the different etiology for narrowing in CS and DS results in a different natural history of pain progression, different locations requiring decompression, and different outcomes following a stability-preserving decompression procedure. STUDY DESIGN/SETTING This study used a retrospective cohort study patient sample: We retrospectively reviewed consecutive patients of a single surgeon with DS or CS who underwent surgical decompression without fusion between 2008 and 2014. Patients were excluded if they had undergone a previous lumbar surgical procedure (decompression or fusion) or follow-up less than 12 months. OUTCOME MEASURES Pre- and postoperative clinical outcome scores including visual analogue scale (VAS) and Oswestry Disability Index (ODI) were recorded. Postoperatively, data were collected regarding complications, the presence of new radicular or myelopathic symptoms, and necessity of reoperation in the lumbar spine. METHODS Demographic information included age, sex, body mass index, smoking status, and Charleston Comorbidity Index (CCI). Preoperative clinical symptoms as well as the presence of lower extremity radiculopathy and claudication were evaluated. Patients were determined to have a diagnosis of CS by the treating surgeon if primary radiographs revealed shortened pedicles and decreased cross-sectional area of the spinal canal as detailed by previous studies. Binary outcomes were compared between congenital and degenerative cohorts using bivariate and multivariate logistic regression. Multivariate regressions controlled for baseline patient and operative characteristics. RESULTS The average age of the DS cohort was 66.7±10.7 years, whereas for the CS group, it was 47.1±9.2 years. Average follow-up was 27.6 months. The patients with DS had significantly more comorbidities as shown by the CCI score (2.8±1.6 vs. 0.5±0.6); p<.001) and the American Society of Anesthesiologists (ASA) score ≥3 (52.8% vs. 11.1%; p<.001). Patients with CS presented with higher VAS back (8.0 vs. 5.1; p=.008) and leg (7.9 vs. 4.5; p<.001) scores. Patients with DS presented with significantly greater duration of preoperative back pain and leg pain (42.7 vs. 30.5 months; p=.042). Postoperatively, there were no significant differences in VAS back, leg, or ODI scores. However, a trend toward a lower VAS leg score was present in the patients with CS when compared with patients with DS (2.6±3.0 vs. 4.2±3.2; p<.117). Both patient groups experienced similar levels of symptomatic relief and improvement in VAS and ODI scores. There were no significant differences in new-onset radicular symptoms requiring conservative treatment or reoperation. In both groups combined, 81.9% of patients reported resolution of lower extremity symptoms at final follow-up. Overall, 20.6% of patients experienced new lower-extremity radicular symptoms after a period of resolution of symptoms postoperatively. There were significantly more reoperations following surgical decompression in patients with DS (13.9% vs. 2.8%; p=.02). CONCLUSIONS Patients with CS and patients with DS respond well to decompression alone, without a supplemental fusion, despite differences in pain experience and presentation. The localization of pathology requiring decompression is similar. The patients with DS were more susceptible to require another operation resulting in a fusion, which confirms the theory that initial microinstability can progress in DS, but is likely not part of the disease process in CS. At just over 2 years after decompression, patients with CS may not need to be treated by a fusion in the setting of lower back pain; however, longer-term follow up is necessary to further assess these outcomes.

Friday, September 28, 2018 3:00 PM–4:00 PM abstracts: optimizing lumbar disc surgery

BACKGROUND CONTEXT Application of nerve root block mainly for the diagnosis but less application in intraoperative treatment. PURPOSE To observe the effect of application of gelatin sponge impregnated a mixture of three drugs (GSIAM) to intraoperative nerve root block to promote early postoperative recovery of lumbar disc herniation (LDH). STUDY DESIGN/SETTING A total of 265 patients with single-level LDH were retrospectively analyzed from January 2013 to October 2017. Patients were divided into intervention group and control group according to whether intraoperative GSIAM. PATIENT SAMPLE A total of 265 patients with single-level LDH were retrospectively analyzed from January 2013 to October 2017. Patients were divided into intervention group and control group according to whether intraoperative GSIAM. OUTCOME MEASURES All patients underwent unilateral MIS-TLIF surgery. Clinical data such as bedbound period, postoperative hospital stays, VAS score of low back pain and leg pain, JOA score, postoperative satisfaction questionnaire results, and therapeutic effect were collected. METHODS A total of 265 patients with single-level LDH were retrospectively analyzed from January 2013 to October 2017. Patients were divided into intervention group and control group according to whether intraoperative application of GSIAM. All patients underwent unilateral MIS-TLIF surgery. Clinical data such as bedbound period, postoperative hospital stays, VAS score of low back pain and leg pain, JOA score, postoperative satisfaction questionnaire results, and therapeutic effect were collected. RESULTS A total of 136 cases were included in the intervention group. A total of 129 cases were included in the control group. The intervention group had significantly shorter bedbound period and postoperative hospital stays than the control group (P CONCLUSIONS Application of GSIAM to intraoperative nerve root block can significantly promote the early postoperative recovery of LDH, and has great short-term clinical efficacy.

Differences in primary and revision deformity surgeries: following 1,063 primary thoracolumbar adult spinal deformity fusions over time

Background This study aims to describe properties of adult spinal deformity (ASD) revisions relative to primary surgeries and determine clinical variables that can predict revision. ASD is a common pathology that can lead to decreased quality of life, pain, physical limitations, and dissatisfaction with self-image. Durability of interventions for deformity treatment is of paramount concern to surgeons, as revision rates remain high. Methods Patients undergoing thoracolumbar fusion, five or more levels, for scoliosis (primary diagnosis ICD-9 737.x) were identified on a state-wide database. Primary and revision (returning for re-fusion procedure) surgeries were compared based on demographic, hospital stay, and clinical characteristics. Differences between primary and revision surgeries, and predictors of primary surgeries requiring revision, utilized binary logistic regression controlling for age, comorbidity burden, and levels fused. Results A total of 1,063 patients (average 7.4 levels fused, mean age: 47.6 years, 69.0% female) undergoing operative treatment for ASD were identified, of which 123 (average 7.1 levels fused, 11.6%, mean age 61.43, 80.5% female) had surgical revision. Primary surgeries were ~0.3 levels longer (P=0.013), used interbody ~11% more frequently (P=0.020), and used BMP ~12% less frequently (P=0.008). Revisions occurred 176.4 days after the primary on average. The most frequent causes of revisions were: 43.09% implant failure, 24.39% acquired kyphosis, and 14.63% enduring scoliosis. After controlling for age, comorbidities, and levels fused older, more comorbid, female, and white-race patients were more likely to be revised. Upon multivariate regression, after controlling for age and levels fused, overall complications remained non-different (OR: 0.8, 95% CI: 0.6-1.2). However, revision remained an independent predictor for infection (OR: 5.5, 95% CI: 2.8-10.5). Conclusions In a statewide database with individual patient follow up of up to 4 years 10% of ASD patients undergoing scoliosis correction required revision. Revision surgeries had higher infection incidence.

Does Reoperation Risk Vary for Different Types of Pediatric Scoliosis

Study Design: Retrospective cohort study of spine fusion surgery utilizing the New York State Inpatient Database. Objective: The objective was to determine whether there were differences in reoperation rates among pediatric scoliosis associated with various etiologies compared with idiopathic scoliosis. Summary of Background Data: The incidence of postoperative complications and reoperations is known to vary among patients with diverse scoliosis pathologies. As these are heterogeneous conditions and often with rare occurrence, it is difficult to compare them in a single study. We aimed to assess reoperation events after fusion for several etiologies of pediatric scoliosis. Methods: The 2008 to 2011 New York State Inpatient Database was queried using International Classification of Diseases (ICD-9-CM) codes for patients with in-hospital stays including a spine arthrodesis for scoliosis. All approaches, all fusion lengths, and ages 10 to 21 were included. Patient identifiers and linkage variables were used to identify revisits. The relative risk of reoperation was calculated for several rare conditions associated with scoliosis. Results: Two thousand three hundred fifty-six pediatric scoliosis fusion surgeries were identified in 2008 in the state of New York. The 1- and 4-year reoperation rate for idiopathic scoliosis was 0.9% and 1.6%, respectively. For nonidiopathic scoliosis, the 1- and 4-year rates were 4.2% and 20.4%, respectively. Of the nonidiopathic scoliosis subtypes, congenital scoliosis (4.7% risk at 1 y, 41.6% at 4 y), the neuromuscular disease arthrogryposis (7.3% risk at 1 y, 28.6% at 4 y), and syndrome neurofibromatosis (9.1% at 1 y, 32.3% at 4 y) showed the highest risk for reoperation. Length of stay and hospital charges were higher for reoperations. Conclusions: Using a large administrative database, we identified neuromuscular, syndromic, and congenital forms of scoliosis that have the highest relative risk for a reoperation within 1 year. At-risk populations should be identified and resources allocated and preventative measures instituted accordingly to prevent these costly events. Level of Evidence: Level III.

Cervical Disc Arthroplasty versus Anterior Cervical Discectomy and Fusion; Utilization and Perioperative Outcomes

Summary of Background Data: Anterior cervical discectomy and fusion (ACDF) is the gold standard surgical intervention for cervical degenerative disc disease (DDD). Cervical disc arthroplasty (CDA) has been introduced as an alternative. CDA offers the potential advantage of preserving intersegmental motion and preventing adjacent segment degeneration. Although a number of trials demonstrated non-inferiority of CDA compared to ACDF in terms of symptom/function related outcomes, little data is available comparing perioperative outcomes. Methods: The Natiowide Inpatient Sample (NIS) database was queried for ACDFs or CDAs between 2005 and 2010. Univariate analyses was used comparing the two procedures in terms of patient demographics, comorbidities, perioperative complications, length of stay (LOS), total hospital charges, and mortality. Complications rates that were significant on univariate analysis were analyzed via logistic regression models that account for age, gender, and overall comorbidity burden. National estimates of annual total number of procedures were calculated. Results: An estimated 9,910 CDAs and 699,289 ACDFs were performed in the United States between 2005 and 2010. The CDA cohort was younger and with less comorbidities than the ACDF cohort. The CDA cohort experienced less post-operative dysphagia, hematoma, acute anemia secondary to intraoperative blood loss, or ARDS. ACDF was associated with less cardiac complications, peripheral vascular, and device related complications. All complications remained statistically significant in logistic regression models. CDA had a lower average LOS (1.56 versus 2.23 days, p<.0001) and was associated with less total charges (

Incidence of Congenital Spinal Abnormalities Among Pediatric Patients and Their Association With Scoliosis and Systemic Anomalies

39,563 versus

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P130. Obese patients may experience worse back pain and less improvement in back pain compared to nonobese patients following lumbar decompression-only surgery

43,477, p<.0001). Mortality was lower after CDA (0.10% versus 0.22%, p=.01). Conclusions: This data suggests that CDA may be safer, associated with lower mortality, lower hospital charges and shorter LOS compared to ACDF. However, baseline differences between the two cohorts, including age and comorbidity burden, may play a confounding role in these findings. This information could be important in developing an evidence-based paradigm for surgical management of cervical DDD.