Repeat surgery after lumbar decompression for herniated disc: the quality implications of hospital and surgeon variation

Abstract

Background context: Repeat lumbar spine surgery is generally an undesirable outcome. Variation in repeat surgery rates may be because of patient characteristics, disease severity, or hospital- and surgeon-related factors. However, little is known about population-level variation in reoperation rates.

Purpose: To examine hospital- and surgeon-level variation in reoperation rates after lumbar herniated disc surgery and to relate these to published benchmarks.

Study design/setting: Retrospective analysis of a discharge registry including all nonfederal hospitals in Washington State.

Methods: We identified adults who underwent an initial inpatient lumbar decompression for herniated disc from 1997 to 2007. We then performed generalized linear mixed-effect logistic regressions, controlling for patient characteristics and comorbidity, to examine the variation in reoperation rates within 90 days, 1 year, and 4 years.

Results: Our cohort included 29,529 patients with a mean age of 47.5 years, 61% privately insured, and 15% having any comorbidity. The age-, sex-, insurance-, and comorbidity-adjusted mean rate of reoperation among hospitals was 1.9% at 90 days (95% confidence interval [CI], 1.2-3.1), with a range from 1.1% to 3.4%; 6.4% at 1 year (95% CI, 3.9-10.6), with a range from 2.8% to 12.5%; and 13.8% at 4 years (95% CI, 8.8-19.8), with a range from 8.1% to 24.5%. The adjusted mean reoperation rates of surgeons were 1.9% at 90 days (95% CI, 1.4-2.4) with a range from 1.2% to 4.6%, 6.1% at 1 year (95% CI, 4.8-7.7) with a range from 4.3% to 10.5%, and 13.2% at 4 years (95% CI, 11.3-15.5) with a range from 10.0% to 19.3%. Multilevel random-effect models suggested that variation across surgeons was greater than that of hospitals and that this effect increased with long-term outcomes.

Conclusions: Even after adjusting for patient demographics and comorbidity, we observed a large variation in reoperation rates across hospitals and surgeons after lumbar discectomy, a relatively simple spinal procedure. These findings suggest uncertainty about indications for repeat surgery, variations in perioperative care, or variations in quality of care.

Figure 1

11-year cumulative incidence of reoperation following decompression surgery for herniated disc in Washington State (solid line). The figure is annotated with point estimates for reoperation rates from other studies on decompression surgery (clinical and administrative).

Figure 2

The reoperation rates within 90-days, 1-year, and 4-years following inpatient lumbar decompression surgery for herniated disc. Each spike represents 95% Bayesian confidence interval for the probability of reoperation within hospitals (figures on left) and surgeons nested within hospitals (figures on right) in Washington State. For the purposes of presentation we excluded those surgeons who have fewer than 10 cases (because of their uninformative low volumes, we could not identify any of them as being significantly above or below the SPORT benchmark). The solid horizontal line represents the overall reoperation rate, while dashed lines represent the reoperation benchmark from SPORT.