COMPARISON OF HEALTH-RELATED QUALITY OF LIFE FOLLOWING FUSION FOR LUMBAR DEGENERATIVE SPONDYLOLISTHESIS WITH HIP AND KNEE JOINT REPLACEMENT SURGERY AND WITH POPULATION NORMS.

Abstract

Introduction: The role of spinal fusion in patients suffering degenerative spine disease may be scrutinized more as costs of surgical treatment rise. Health-related quality of life (HRQL) measurement instruments enable outcome comparisons following treatment of different medical conditions. Rampersaud et al (1) recently presented the results of a comparative study of HRQL outcomes after surgery for lumbar spinal stenosis and hip and knee total joint arthroplasty. The latter are now accepted benchmarks for improvement in patient health.

Methods: A retrospective, observational cohort study was undertaken of 12-item Short Form Health Survey (SF-12) outcome data of 105 consecutive patients of two surgeons (1st and 2nd authors) who underwent single level Posterior Lumbar Interbody Fusion (PLIF) for lumbar spinal stenosis associated with degenerative spondylolisthesis. Minimum 12-month (F/U) data was available for 98 patients (93%). Comparison was made with published SF-12 results of hip and knee total joint arthroplasty (THR and TKR) and with age-related Australian population norms. Analyses were performed using XLSTAT version 7.5.3. Non-parametric statistics were used for assessment of skewed continuous variables. Overlappng 95%CIs were interpreted as indicating lack of significant difference in outcomes between patient and population groups.

Results: Median follow-up was 24months (range: 12–60months). Median age was 65 (Interquartile range: 59–75) years. Male:female ratio 2.8:1

Mean (95%CI) pre-op Physical Component Summary score (PCS) was 28.1 (26.6–29.5). This increased at last F/U to 39.3 (36.9–41.7, P< 0.0001). Mean Mental Component Summary score (MCS) was 47.8 (45.5–50.1) pre-op and 52.3 (50.2–54.5) at last F/U (P=< 0.0001).

While there was no difference in patient demographics, a significant difference existed in the pre-op SF-12 scores between the patients of the two surgeons (mean PCS: 24.9 (22.7–27.0) vs. 29.6 (27.8–31.5) and MCS: 44.0 (39.3–48.6) vs. 49.5 (46.8–52.1)). No significant difference was found in the improvements in mean SF-12 scores between these two patient groups (PCS: 12.3 (7.6–17.1) vs. 10.8 (8.3–13.3) and MCS: 6.3 (1.8–10.8) vs. 3.0 (0.3–5.6)) or in the SF-12 scores at 12-months (PCS: 37.2 (32.8–41.6) vs. 40.2 (37.2–43.2) and MCS: 52 (48.3–55.7) vs. 52.3 (50.1–54.4)). No significant difference was found between post-op PCS of the less disabled patient group or MCS scores of either group and published SF-12 age-matched population norms (65–74 years: mean PCS of 44.4 (42.7–46.1) and MCS of 53.8 (52.7–55.0)).

Three published series (869 patients) were located providing SF-12 data for TKR surgery. Weighted mean age was 69 years and pre-op PCS was 30 (range:27–34). 12-month improvement in PCS was 7.0 (range:7–8.5). For THR, one paper (147 patients from 3 hospitals) containing SF-12 data was found. Mean age was 68 years (range:36–89). Mean pre-op PCS and MCS of 30.5 and 41.4, increased to 45.6 and 49.7 at one year.

Discussion: The current study shows that spinal fusion can return patients’ HRQL to that of age-matched population norms and yield outcomes comparable to those of total hip and knee arthroplasty. Strict comparison with the arthroplasty literature was problematic however owing to variations in the methodology of their data presentation. Prospective collaboration with surgical colleagues in other disciplines is required.