Study Design. A retrospective outcomes study.
Objectives. To examine the outcome following adjacent two-level lumbar discectomy using both surgeon-based evaluation criteria and validated patient-based quality of life instrument (SF-36).
Summary of Background Data. Lumbar discectomies have documented success rates between 49% and 98% for single-level procedures. However, no prior study has specifically examined the outcome following adjacent two-level lumbar discectomy in a large series of patients.
Methods. This study analyzed 55 patients with a minimum 2-year follow-up. All patients underwent adjacent two-level lumbar discectomy for radicular pain attributable to nerve root impingement at the corresponding levels. The patients were divided into two diagnostic groups based on their preoperative radiographic studies. Patients with two-level adjacent posterolateral lumbar disc herniations without concomitant osseous degenerative changes at the same levels constituted Group 1 (22 patients). Patients with associated osseous degenerative changes at the same levels made up Group 2 (33 patients). The patients' clinical outcome was assessed using the MacNab classification and SF-36 questionnaire.
Results. The average duration of follow-up was 41 months (range 24-96 months). The group consisted of 35 males and 20 females with average age of 49 years (range 19-82 years). Excellent results were observed in 49%, good in 20%, fair in 15%, and poor in 16%. However, patients in Group 1 have 86% excellent/good results, whereas patients in Group 2 have 57% excellent/good results. Overall, 15% of the patients required reoperation and subsequent spinal fusion. Analysis of the SF-36 scores revealed significant differences based on patient's diagnostic grouping as well. Patients in Group 1 have physical and mental summary scores comparable with age- and sex-adjusted population norms and significantly higher than those in Group 2 (P < 0.01).
Conclusions. Two-level discectomy is an effective treatment with clinical outcome comparable with single-level discectomy. Patients with posterolateral disc herniations and definitive radiculopathy without osseous degenerative changes at the same levels have better clinical outcome and quality of life scores compared with those patients having concomitant degenerative arthritis at the same levels. Patients having two-level discectomy may be at increased risk of requiring subsequent lumbar fusion compared with those with single-level discectomy.
Lumbar discectomy is a common operation and numerous outcome studies are available in the literature. The reported success rate for lumbar discectomy ranges from 49% to 98%, depending on the duration of follow-up, the patient selection, and the clinical criteria used. 1-13 Most studies concur that early results of surgical discectomy are highly successful (>90%) 7 but the results have been less positive with long-term follow-up. 5,8 Furthermore, most measures of outcome are based on subjective criteria such as patient's self-reported satisfaction, surgeon's rating of the success, or the need for second procedure.
Recent studies have emphasized clinical results based on patient-based outcome instruments such as the Short Form-36 (SF-36). The SF-36 is a standardized tool designed for evaluation of health status in all adult population. 14,15 Using the SF-36, several studies have demonstrated the improvement in the patient's quality of life following surgical intervention such as total joint arthrosplasty, 16 rotator cuff repair, 17 and single-level lumbar microdiscectomy. 7 The SF-36 scores is also validated, therefore enabling comparisons between different clinical outcome studies.
To our knowledge, no study has specifically examined the clinical outcome following adjacent two-level lumbar discectomy. The goal of this article is to examine the outcome following this procedure using both surgeon-based evaluation criteria and a validated patient-based instrument (SF-36). In addition, variables that may affect the clinical outcome, as well as the correlation between the surgeon-based and patient-based evaluation criteria, are examined.