Osteoporosis is not associated with reoperation or pseudarthrosis after anterior cervical discectomy and fusion through 4-years' follow-up: a retrospective cohort study of US academic health centers.

Background context: Osteoporosis has been proposed as a risk factor for reoperation after anterior cervical discectomy and fusion (ACDF), yet this potential association has been understudied, with conflicting results to date.

Purpose: This study examines the hypothesis that adults with osteoporosis would have an increased risk of reoperation after ACDF compared to matched adults without osteoporosis.

Study design/setting: Retrospective cohort study.

Patient sample: Two matched cohorts (mean age: 62 years; 75% female), each with 1,019 patients, who underwent primary ACDF. Cohorts were determined by the presence or absence of a diagnosis of osteoporosis.

Outcome measures: Incidence of reoperation occurring over 4 years postoperatively, with our primary outcome being the risk ratio (RR) of reoperation with 95% confidence intervals (CI). Secondary outcomes included risk and mean count of oral opioid prescriptions and risk of pseudoarthrosis.

Methods: We utilized the TriNetX network to identify adults undergoing their first ACDF from 2004 to 2020, excluding those with serious pathology, and divided patients into 2 cohorts: osteoporosis and nonosteoporosis. Patients were propensity matched according to key risk factors for reoperation.

Results: Patients with osteoporosis had no statistically significant or meaningful difference in risk of reoperation compared to nonosteoporotic patients over 4-years' follow-up [95% CI] (17.3% vs. 16.5%; RR: 1.05 [0.86, 1.27]; p=.6361). Similarly, there were no significant differences in the risk of pseudoarthrosis (26.5% vs. 29.1%; RR: 0.91 [0.79, 1.05]; p=.1820), oral opioid prescription (75.0% vs. 76.0%; RR: 0.99 [0.94, 1.04]; p=.6067), or mean oral opioid prescription count (11.5 vs. 11.8; p=.7040).

Conclusion: Compared to matched nonosteoporosis controls, osteoporosis was not associated with a statistically significant or clinically meaningful increase in risk of reoperation in adults over 4 years after ACDF. Furthermore, osteoporosis was not associated with a significant or meaningful risk of pseudoarthrosis or oral opioid prescription after ACDF, although more research is needed for corroboration. Additional research is needed to clarify whether those with osteoporosis have meaningful differences in pain and function compared to those without osteoporosis following ACDF.