Rates and reasons for reoperation within 30 and 90 days following cervical spine surgery: a retrospective cohort analysis of the Michigan Spine Surgery Improvement Collaborative (MSSIC) registry

BACKGROUND CONTEXT Reoperation following cervical spinal surgery negatively impacts patient outcomes and increases health care system burden. To date, most studies have evaluated reoperations within 30 days after spine surgery and have been limited in scope and focus. Evaluation within the 90-day period, however, allows a more comprehensive assessment of factors associated with reoperation. PURPOSE The purpose of this study is to assess the rates and reasons for reoperations after cervical spine surgery within 30 and 90 days. DESIGN We performed a retrospective analysis of a state-wide prospective, multi-center, spine-specific database of patients surgically treated for degenerative disease. PATIENT SAMPLE Patients 18 years of age or older who underwent cervical spine surgery for degenerative pathologies from February 2014 to May 2019. Operative criteria included all degenerative cervical spine procedures, including those with cervical fusions with contiguous extension down to T3. OUTCOME MEASURES We determined causes for reoperation and independent surgical and demographic risk factors impacting reoperation. METHODS Patient-specific and surgery-specific data was extracted from the registry using ICD-10-DM codes. Reoperations data was obtained through abstraction of medical records through 90 days. Univariate analysis was done using chi-square tests for categorical variables, t-tests for normally distributed variables, and Wilcoxon rank-sum tests for variables with skewed distributions. Odds ratios for return to the operating room (OR) were evaluated in multivariate analysis. RESULTS A total of 13,435 and 13,440 patients underwent cervical spine surgery and were included in the 30 and 90-day analysis, respectively. The overall reoperation rate was 1.24% and 3.30% within 30 and 90 days, respectively. Multivariate analysis showed within 30 days, procedures involving four or more levels, posterior only approach, and longer length of stay had increased odds of returning to the OR (p<.05), whereas private insurance had a decreased odds of return to OR (p<.05). Within 90 days, male sex, coronary artery disease (CAD), previous spine surgery, procedures with 4 or more levels, and longer length of stay had significantly increased odds of returning to the OR (p<.05). Non-white race, independent ambulatory status pre-operatively, and having private insurance had decreased odds of return to the OR (p<.05). The most common specified reasons for return to the OR within 30 days was hematoma (19%), infection (17%), and wound dehiscence (11%). Within 90 days, reoperation reasons were pain (10%), infection (9%), and hematoma (8%). CONCLUSION Reoperation rates after elective cervical spine surgery are 1.24% and 3.30% within 30 and 90 days, respectively. Within 30 days, four or more levels, posterior approach, and longer length of stay were risk factors for reoperation. Within 90 days, male sex, CAD, four or more levels, and longer length of hospital stay were risk factors for reoperation. Non-white demographic and independent preoperative ambulatory status were associated with decreased reoperation rates.