Risk factors for 90-day reoperation and readmission after lumbar surgery for lumbar spinal stenosis.

OBJECTIVES: The objective of this study was to evaluate the incidence and risk factors for 90-day readmission and reoperation after elective surgery for lumbar spinal stenosis (LSS).

METHODS: The authors performed a retrospective consecutive cohort analysis of patients undergoing posterior lumbar decompression with or without fusion for LSS with claudication from January 2014 through December 2015.

RESULTS: Data were collected on 1592 consecutive patients. The mean age at surgery was 67.4 ± 10.1 years and 45% of patients were female. The 90-day reoperation rate was 4.7%, and 69.3% of the reoperations occurred within the first 30 days. The 90-day readmission rate was 7.2%. Multivariable analysis showed that postoperative development of a surgical site infection (SSI; odds ratio [OR] 14.09, 95% confidence interval [CI] 7.86–25.18), acute kidney injury (AKI; OR 6.76, 95% CI 2.39–19.57), and urinary tract infection (UTI; OR 3.96, 95% CI 2.43–6.37), as well as a history of congestive heart failure (CHF; OR 3.03, 95% CI 1.69–5.28), were significant risk factors for readmission within 90 days. Male sex (OR 0.60, 95% CI 0.38–0.92) was associated with decreased odds for readmission. With regards to reoperation, development of SSI (OR 25.06, 95% CI 13.54–46.51), sepsis (OR 7.63, 95% CI 1.52–40.59), UTI (OR 2.54, 95% CI 1.31–4.76), and increased length of stay (LOS; OR 1.25, 95% CI 1.17–1.33) were found to be significant risk factors. A subsequent analysis found that morbid obesity (OR 6.99), history of coronary artery disease (OR 2.263), increased duration of surgery (OR 1.004), and LOS (OR 1.07) were significant risk factors for developing an SSI.

CONCLUSIONS: Overall, this study found rates of 4.7% and 7.2% for reoperation and readmission, respectively, within 90 days: 30.7% of the reoperations and 44.7% of the readmissions occurred beyond the first 30 days. A diagnosis of SSI, AKI, UTI, and history of CHF were significant factors for readmission, while male sex was associated with decreased odds for readmission. A diagnosis of SSI, sepsis, UTI, and increased LOS were found to be significant predictors for reoperation. Understanding 90-day complication rates is imperative because there has been increased discussion and healthcare policy extending the global postoperative window to 90 days. Current literature supports a readmission rate of 3%–9% after spine surgery. However, this literature either is limited to a 30-day window or does not stratify between different types of spine surgeries.

ABBREVIATIONS: AKI = acute kidney injury; BPH = benign prostate hyperplasia; CAD = coronary artery disease; CHF = congestive heart failure; CI = confidence interval; CMS = Centers for Medicare and Medicaid Services; COPD = chronic obstructive pulmonary disease; DM = diabetes mellitus; EBL = estimated blood loss; LOS = length of stay; LSS = lumbar spinal stenosis; OR = odds ratio; POUR = postoperative urinary retention; SSI = surgical site infection; UTI = urinary tract infection.