80. Bariatric surgery prior to elective anterior cervical discectomy and fusion in obese patients is associated with a reduced risk of 90-day postoperative complications and readmissions

Abstract

BACKGROUND CONTEXT Obese patients, particularly those with a body mass index (BMI) ≥35 kg/m2, pose a major challenge for a spine surgeon. Though obesity has previously been shown to be linked with adverse outcomes following elective spine surgical procedures, the impact of prior bariatric surgery on altering postoperative outcomes following elective anterior cervical discectomy and fusions (ACDFs) has not been explored. PURPOSE To evaluate whether bariatric surgery prior to ACDF in obese Medicare patients reduces the risk of experiencing adverse postoperative outcomes. STUDY DESIGN/SETTING Retrospective review of 100% Medicare Claims Database. PATIENT SAMPLE The PearlDiver program was used to query the 2007-2013 100% Medicare Standard Analytical Files (SAF100) for patients undergoing an elective ACDF using International Classification of Diseases 9th Edition (ICD-9) procedure codes 81.02. Records were filtered to include only those patients who underwent a 1- to 2-level surgery using ICD-9 procedure code 81.62. Only those patients receiving an ACDF due to degenerative spine pathologies were included in the study. Finally, patients who did not have active enrollment up to 2 years prior and 1 year after the surgery were excluded. A total of 121,382 patients undergoing an elective 1- to 2-level ACDF were included in the final cohort. OUTCOME MEASURES ICD-9 diagnosis codes were used to identify patients having at least moderate/Class II obesity (V85.35-V85.45, V85.4 and 278.01) within the last 2 years prior to an ACDF. Based on previously published literature, ICD-9 procedure codes for high gastric bypass (44.31), laparoscopic gastroenterostomy (44.38), other gastroenterostomy without gastrectomy (44.39), laparoscopic gastroplasty (44.68), laparoscopic gastric restrictive procedure (44.95-44.98), insertion of gastric bubble (44.93), other repair of stomach (44.69), open and other partial gastrectomy (43.89), isolation of intestinal segment (45.50-45.51), intestinal anastomosis (45.90, 45.91), partial gastrectomy with anastomosis to esophagus (43.5), duodenum (43.6) and jejunum (43.7) and other operations on stomach, unspecified (44.99) being coded on the same day as an obesity code were used to categorize patients receiving a bariatric surgical procedure.Only those patients receiving a bariatric surgery within 2 years prior to an ACDF were included. The 2-year mark was chosen as an arbitrary value. The study cohort was divided into two groups: (1) obese ACDF patients (BMI ≥35) receiving a bariatric surgery procedure within two years prior to an ACDF and (2) obese ACDF patients (BMI ≥35) without a known history of a bariatric surgical procedure within the last 2 years. Primary outcomes included 90-day complications (wound, pulmonary, cardiac, sepsis, renal, deep venous thrombosis, pain and dysphagia), 90-day readmissions, 90-day and 1-year revision cervical fusions. METHODS Multivariate analyses were used to assess the impact of prior bariatric surgery on 90-day outcomes following ACDF, after adjusting for age, gender, region and Elixhauser Co-morbidity Index. RESULTS A total of 6,128 patients with a BMI >35kg/m2 underwent ACDF, of which 411 ACDF patients underwent a bariatric surgical procedure within the 2 years prior to an ACDF. Multivariate analysis adjusting for age, gender, region and Elixhauser Co-morbidity Index (ECI), demonstrated that a history of prior bariatric surgery was associated with a significantly reduced rate of 90-day pulmonary complications (6.6% vs 12.7%, OR 0.53 [95% CI 0.34-0.78]; p=0.002), cardiac complications (15.3% vs 24.2%, OR 0.69 [95% CI 0.51-0.92]; p=0.012), sepsis (9.5% vs 15.1%, OR 0.69 [95% CI 0.48-0.96]; p=0.035), renal complications (2.9% vs 7.1%, OR 0.54 [95% CI 0.28-0.94]; p=0.044) and 90-day readmissions (3.9% vs 8.0%, OR 0.53 [95% CI 0.30-0.85]; p=0.015). Prior bariatric surgery had no statistically significant impact on the rates of wound complications (p=0.325), deep venous thrombosis (p=0.176), pain complications (p=0.606), dysphagia (p=0.171), 90-day revision (p=0.875) and 1-year revisions (p=0.313). CONCLUSIONS Surgery-induced weight loss prior to an ACDF in obese patients is associated with reduced 90-day complication and readmission rates. Orthopedic and bariatric surgeons should counsel obese patients on the benefits of bariatric surgery following ACDFs. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.