A PROSPECTIVE AND CONSECUTIVE STUDY OF SURGICALLY TREATED LUMBAR SPINAL STENOSIS - PART-II - 5-YEAR FOLLOW-UP BY AN INDEPENDENT OBSERVER

Study Design. A prospective and consecutive study of surgical results obtained during serial follow-up investigations in patients who underw ent surgery for central lumbar spinal stenosis. Objectives. To evaluat e the result after surgical decompression for lumbar spinal stenosis, at regular intervals after surgery. and to correlate these results wit h values for preoperative parameters; special interest was focused on the results in relation to the degree of constriction of the spinal ca nal. Summary of Background Data. The outcome after surgery for spinal stenosis is debatable; long-term follow-up investigations have indicat ed deterioration with passing time. Results of studies in nonsurgical patients have demonstrated that the symptoms do not progress with time . Results of a meta-analysis of the literature on surgical results hav e demonstrated a wide variation of outcomes. Material and Methods. In a prospective study, 105 consecutive patients who underwent surgical d ecompression (laminectomy with facet-preserving technique, but no fusi on) were evaluated at follow-up examinations 4 months and 1, 2, and 5 years after surgery. At the follow-up examinations, the patient's opin ion on the surgical result was registered, using a four-grade scale. T he occurrence of pain at rest and at night was registered, as well as the patient's walking ability. Statistical analysis was performed, rel ating the surgical results to patient age, gender, preoperative durati on of symptoms and radiographically observed constriction as described in Part I of this study. The radiologist was blinded to patient outco me. Logistic regression analysis was performed. Results. During the fo llow-up period, 19 patients underwent reoperation, consisting of fusio n to treat lumbar pain (n = 4), repeat decompression because of progre ssive stenosis (n = 13), and repairs in response to surgical complicat ions (n = 2). Follow-up results: The result, related to the recurrence of leg symptoms, deteriorated with passing time. Excellent results we re reported by 63% to 67% at 4-month and 2-year follow-ups compared wi th 52% at the 5-year follow-up. There was a correlation between the co nstriction of the spinal canal and the outcome at all intervals. Patie nts with an anteroposterior diameter of 6 mm or less at the narrowest site had significantly better results. The logistic regression analysi s demonstrated a significant correlation between a severe reduction of the anteroposterior diameter and excellent results and a tendency tow ard better results in patients with a shorter preoperative duration of symptoms. Improvements of walking ability was also associated with a pronounced constriction of the spinal canal. Conclusion. The results a fter surgical decompression in patients with central spinal stenosis d eteriorated with time. There was a significant correlation between goo d result and pronounced constriction of the spinal canal. Patients wit h a preoperative duration of symptoms of less than 4 years and patient s with no preoperative back pain tended to have better surgical outcom es. The reoperation rate was 18% within 5 years. When surgery for spin al stenosis is contemplated, these prognostic factors should be taken into consideration: The ''ideal patient'' has a pronounced constrictio n of the spinal canal, insignificant lower back pain, no concomitant d isease affecting walking ability, and a symptom duration of less than 4 years.