Faculty Bibliography

BACKGROUND: Postoperative wound complications after posterior spinal fusion are difficult to manage. The incidence in the nonidiopathic patient population is significantly higher than the adolescent idiopathic population. A comparison of wound complications after posterior spinal fusion for nonidiopathic scoliosis between the utilization of the orthopaedic surgical team at the time of closure performing a nonstandardized wound closure versus a plastic surgeon with a plastic multilayered closure technique and rotational flap coverage when needed had not previously been evaluated. The purpose of this study was to compare the complication rate between nonstandardized and plastic multilayered closure of the surgical incision in patients undergoing posterior spinal fusion for nonidiopathic scoliosis. METHODS: The charts of 76 patients with a primary diagnosis of scoliosis associated with a syndrome or neuromuscular disease and who underwent a posterior spinal fusion were reviewed. Forty-two patients had their incisions closed using the nonstandardized technique and 34 using the plastic multilayered technique. These 2 groups were compared for age, sex, primary diagnosis, number of levels fused, estimated blood loss, number of units transfused, operating room time, wound complication, and return to operating room. RESULTS: The wound complication rate in the nonstandardized closure group was 19% (8/42) compared with 0% (0/34) in the plastic multilayered closure group (P=0.007). The unanticipated return to the operating room rate was 11.9% (5/42) for the nonstandardized closure patients versus 0% (0/34) for the plastic multilayered closure patients (P=0.061). CONCLUSIONS: The use of the plastic multilayered closure technique in this patient population is important in an effort to decrease postoperative wound complications. The ability of the surgical team to decrease the infection rate of nonidiopathic scoliosis cannot be overstated. The method of wound closure plays a major role in lowering this incidence. LEVEL OF EVIDENCE: Level III-therapeutic.

DESIGN:Retrospective review. OBJECTIVE:To evaluate gender-related differences in compensatory recruitment to progressive sagittal malalignment. SUMMARY OF BACKGROUND DATA:Recent research has elucidated compensatory mechanisms recruited in response to sagittal malalignment, but gender-specific differences in compensatory recruitment patterns is unknown. METHODS:Single-center study of patients with full body x-rays. A female group was propensity matched by age, body mass index (BMI), and pelvic incidence (PI) to a male group. Patients were then stratified into five groups of progressive PI-lumbar lordosis (LL) mismatch (<0°, 0°-10°, 10°-20°, 20°-30°, >30°). Differences between PI-LL groups were assessed with analysis of variance, and between genders by unpaired t test. Knee flexion to pelvic tilt (PT) ratio was computed and compared between genders. Multivariate regression to develop predictive models for PT was performed for each gender, first with spinopelvic parameters and subsequently with inclusion of lower limb parameters. RESULTS:A total of 942 patient visits were included: 471 females (mean age 54 years, BMI 27, PI 51°) and 471 males (mean age 52 years, BMI 27, PI 51°). At the lowest level of malalignment, females had greater PT and less knee flexion. With progressive malalignment, females continued to exhibit a pattern of greater pelvic retroversion and less knee flexion compared to males. Hip extension was higher in females with progressive PI-LL mismatch groups. Both genders progressively recruited knee flexion and pelvic retroversion with increased PI-LL mismatch, except that at the higher PI-LL mismatch groups, only males continued to recruit knee flexion (all p < .05). Inclusion of lower limbs in the regression for PT markedly improved correlation coefficients for females but not for males. CONCLUSIONS:With progressive sagittal malalignment, men recruit more knee flexion and women recruit more pelvic tilt and hip extension. Knee flexion is a possible mechanism to gain pelvic tilt for females whereas for males, knee flexion is an independent compensatory mechanism.

BACKGROUND: Though previous studies have shown improved outcomes associated with higher volume surgeons and hospitals, this may not be replicated in ASDS due to case complexity variation. We hypothesized that high-volume surgeons perform more complex surgeries. Therefore, we defined an Operative Complexity Index (OCI), specifically for the National Inpatient Samples (NIS) data, which provides information on in-hospital postoperative complications, to assess rates of adult spine deformity surgery (ASDS) cases as they relate to surgeon and hospital operative volume. METHODS: The 2001 to 2010 NIS was queried for patients greater than 21 years of age with in-hospital stays, including a spine arthrodesis for a diagnosis of scoliosis. Surgeon and hospital identifiers were used to allocate records into volume quartiles by number of surgeries per year. The OCI was devised considering the number of fusion levels, surgical approach, revision status, and use of osteotomy. The index was validated using blood-loss-related diagnostic and procedural codes. One-way ANOVA assessed continuous measures. Chi-square assessed categorical measures. RESULTS: 141,357 ASDS cases met the inclusion criteria. High-volume surgeons performed a higher rate of longfusions (> 8 levels), revision surgeries, and surgeries requiring osteotomy. The OCI showed weak, but significant, correlation with blood loss values: acute blood loss anemia (r = 0.21) and treatment with blood products (r = 0.12) (p < 0.001). High OCI also was also associated with increased length of stay (r = 0.27) and total charges (r = 0.41) (p < 0.001). CONCLUSIONS: The operative complexity index (OCI) for ASDS increases with high-volume surgeons and centers, indicating it can be useful to adjust for surgical invasiveness in the NIS database. Operative complexity must be considered when evaluating patient safety and quality indices among hospitals and surgeons.

INTRODUCTION: Bone morphogenetic protein (BMP) can 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. We sought to examine adolescent idiopathic (AIS) and non-idiopathic scoliosis (NIS) for reoperation events with and without the use of BMP using a large statewide database. METHODS: The 2008-2011 New York State Inpatient Database was queried using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes. Patients age 10 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 two cohorts for relative risk assessment. RESULTS: A total of 2,658 and 2,431 cases were identified of AIS and NIS, respectively. The use of BMP at the initial visit was performed at a rate of 4.5% for AIS and 21.0% for NIS fusion surgery. For posterior fusion cases longer than eight levels, the reoperation rate for pseudarthrosis was 1.0% in AIS and 18.4% in NIS (p < .001). For NIS fusions greater than eight levels, the rate of reoperation for pseudarthrosis after using BMP at the index surgery was 5% and 22% when BMP was not used, a relative risk of 4.0 (p < .001). For AIS, there was no substantial increase in risk when not using BMP for fusion greater than eight levels (p < .001). CONCLUSION: We found a significant decrease in the risk of reoperation for pseudarthrosis after long fusions when using BMP in the case of NIS. In contrast, use of BMP does not benefit the AIS population.

BACKGROUND: Pre-donation of autologous blood prior to spine fusion for adolescent idiopathic scoliosis (AIS) has been used in deformity surgery. The effect of pre-donation on pre-operative hematocrit (Hct) remains debated. Multiple factors may influence pre-operative Hct including intravascular volume status, patient factors, and timing of pre-operative blood donation. The purpose of this study was to determine if pre-donation significantly lowers pre-incision Hct in AIS patients. METHODS: A retrospective cohort study of a Level-1 prospective randomized trial was conducted. 125 patients from the homogeneous population were included. AIS patients undergoing a posterior only spinal fusion for AIS were separated into two groups based on their pre-operative blood donation history. Demographic variables, pre-incision Hct, and transfusion rates were compared between the two groups using the Student's T-test. RESULTS: Pre-donation and non pre-donation groups had 28 and 97 patients, respectively. Pre-donation group was 75% female (21F, 7M) and non pre-donation group was 78% female (76F, 21M). There was no difference between pre-donation and non pre-donation groups in mean age (15.6 +/- 2.2 vs 14.8 +/- 2.2, p = 0.081), BMI (23.1 +/- 4.2 vs 21.7 +/- 5.3, p = 0.219), and pre-incision Hct (32.8 +/- 3.4 vs 33.8 +/- 3.1, p = 0.628). The overall transfusion rates were equivalent (32.1+/- 48.0% vs 25.8 +/- 44.0%, p = 0.509), however, the rate of allogenic transfusion for the pre-donation group was significantly lower (3.6 +/- 18.9% vs 25.8 +/- 44.0%, p = 0.011). CONCLUSIONS: This study supports the use of pre-donation for AIS, without a significant drop in pre-incision Hct. Patients that donate are also much less likely to be exposed to allogenic blood. There may be a surgeon bias to recommend pre-donation in patients with a larger BMI and older age. Future studies are needed from a larger population of patients including those with non-AIS pathology. LEVEL OF EVIDENCE: Level III.

STUDY OBJECTIVE: Perioperative thrombotic complications after orthopedic surgery are associated with significant morbidity and mortality. The use of aspirin to reduce perioperative cardiovascular complications in certain high-risk cohorts remains controversial. Few studies have addressed aspirin use, bleeding, and cardiovascular outcomes among high-risk patients undergoing joint and spine surgery. DESIGN/SETTING/PATIENTS: We performed a retrospective comparison of adults undergoing knee, hip, or spine surgery at a tertiary care center during 2 periods between November 2008 and December 2009 (reference period) and between April 2013 and December 2013 (contemporary period). MEASUREMENTS: Patient demographics, comorbidities, management, and outcomes were ascertained using hospital datasets. MAIN RESULTS: A total of 5690 participants underwent 3075 joint and spine surgeries in the reference period and 2791 surgeries in the contemporary period. Mean age was 61+/-13 years, and 59% were female. In the overall population, incidence of myocardial injury (3.1% vs 5.8%, P<.0001), hemorrhage (0.2% vs 0.8%, P=.0009), and red blood cell transfusion (17.2% vs 24.8%, P<.001) were lower in the contemporary period. Among 614 participants with a preoperative diagnosis of coronary artery disease (CAD), in-hospital aspirin use was significantly higher in the contemporary period (66% vs 30.7%, P<.0001); numerically, fewer participants developed myocardial injury (13.5% vs 19.3%, P=.05), had hemorrhage (0.3% vs 2.1%, P=.0009), and had red blood cell transfusion (37.2% vs 44.2%, P<.001) in the contemporary vs reference period. CONCLUSIONS: In a large tertiary care center, the incidence of perioperative bleeding and cardiovascular events decreased over time. In participants with CAD, perioperative aspirin use increased and appears to be safe.

Introduction/objectives: Spinal deformity has a known deleterious effect upon the outcomes of THA and acetabular component positioning. This study sought to evaluate the relationship between severity of spinal deformity parameters and acetabular cup position, rate of dislocation, and rate of revision among patients with THAs and concomitant spinal deformity. Methods: A prospectively database of patients with spinal deformity was reviewed and patients with THA were identified. The full standing stereoradiographic images (EOS) were reviewed. Spinal deformity parameters and acetabular cup anteversion and inclination were measured. A chart review was performed to determine dislocation and revision arthroplasty events. Statistical analysis was performed to determine correlation of deformity with acetabular cup position. Subgroup analysis was performed for spinal fusion, dislocation events, and revision THA. Results: 142 patients were identified with THA and spinal deformity, with 152 hips. The rate of dislocation was 5.7%, with a revision rate of 3.6% for instability. Only 42.1% met the radiographic "safe zone" criteria. 7 (77.8%) of the 9 dislocations occurred in patients with acetabular cups outside the safe zone (p = 0.304). Patients with dislocations had significantly higher inclination than those patients who did not dislocate (p = 0.016), but had no difference in anteversion (p = 0.646). Conclusions: In this cohort, patients with THA and concomitant spinal deformity have a high dislocation rate and a high percentage of acetabular cups which lie outside the safe zone in the standing position. Known spinal deformity parameters and the presence of spinal fusion do not correlate strongly with cup position or dislocation rates

STUDY DESIGN: Retrospective review of a prospective multicenter database evaluating surgical adult spinal deformity (ASD) patients. OBJECTIVE: This study aims to identify risk factors for medical complications in ASD patients undergoing surgery. SUMMARY OF BACKGROUND DATA: ASD surgery is known for its high complication rate. This study examines baseline patient characteristics for predictors of medical complications in surgical ASD patients. METHODS: Intra and perioperative medical complications were included. Medical complications were: infection, pneumonia, urinary tract infection, c-difficile, sepsis, stroke, delirium, deep venous thrombosis, pulmonary embolism, myocardial infarction, arrhythmia, congestive heart failure, pneumothorax, atelectasis, adult respiratory distress syndrome, bowel obstruction, ileus, and renal failure. Potential predictors were identified using univariate testing. Multivariate Poisson regression was used to determine independent predictors of medical complications. Health-related quality of life (HRQL) was measured using the Oswestry Disability Index and SF-36. Multivariate repeated measures mixed models were used to examine HRQL. RESULTS: Four hundred forty-eight patients were included. The incidence of patients with at least one medical complication was 26.8%. Potential predictors included: age, BMI, anemia, arthritis, depression, cardiac history, hypertension, lung disease, history of PVD, Charlson Comorbidity Index, ASA, smoking, sex, and the number of years with spine problems. Independent predictors identified on multivariate logistic regression modeling included hypertension (IRR 2.43 P = 0.0001), smoking (IRR 2.49 P = 0.0001), and number of years with spine problems (IRR 1.23 P = 0.03). Despite medical complications, patients experienced significant improvements in HRQL, as measured by the SF-36 (P = 0.0001) and oswestry disability index (P = 0.0001). The rate of improvement and overall improvement compared with baseline were not statistically different than that of patients who did not experience medical complications. CONCLUSION: Risk factors for the development of postoperative medical complications after correction of ASD include smoking, hypertension, and duration of symptoms. Patients who have one or more of these risk factors should be identified and informed during informed consent of their increased risks. They should be optimized preoperatively, and followed closely during the postoperative period. LEVEL OF EVIDENCE: 3.