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Objective: The objective of this study was to conduct a comparative quantitative analysis of outcomes, radiographic findings, and magnetic resonance imaging results after laminectomy or laminotomy was performed for patients with lumbar stenosis. Such as analysis had not previously been conducted., Methods: Twenty-six patients with no exclusion criteria who were treated surgically for acquired stenosis at the Division of Neurological Surgery at The Ohio State University from 1990 to 1993 were studied retrospectively. At follow-up examinations, each patient completed a detailed questionnaire that included visual analog scales, functional assessments, and the medical outcome study short form health survey, SF-36. Each patient underwent plain static and dynamic radiography that detailed vertebral body sagittal listhesis and rotation and magnetic resonance imaging that evaluated dural sac compression., Results: The mean follow-up duration was 36.7 months. Good outcome was defined by the presence of three criteria: no greater than mild leg pain (Grades 0-4), the ability to walk more than one block without developing lower extremity pain, and the ability to walk without assistance devices. Fifty-eight percent of the patients who had undergone laminectomies and 50% of the patients who had undergone laminotomies had good outcomes. All were judged to have had adequate decompression. The average maximum postoperative listhesis was 17.3 +/- 9.9% in the laminectomy group and 17.6 +/- 12.5% in the laminotomy group. In contrast to some previous studies, pre- or postoperative listhesis was not statistically related to outcome in either group. Patients in each poor outcome category seemed to have worse comorbid medical conditions than did patients in the good outcome category. The SF-36 measurements of poor functioning because of health factors and bodily pain correlated somewhat with poor outcomes in the patients who had undergone laminectomies. In patients who had undergone laminotomies, the only statistically significant finding among the outcome groups was the effect of poor emotional health on activity for the patients with poor outcomes., Conclusion: This study indicates that laminotomy can adequately decompress lumbar canal stenosis, that laminectomy and laminotomy have the same degree of postoperative listhesis, and that the quantitative outcome of any treatment for lumbar stenosis is dependent not only on surgical factors but also on comorbid physical and psychological factors.

Between 1986 and 1990, 37 of 72 patients undergoing decompressive lumbar laminectomy with medial facetectomy for lumbar stenosis at The Ohio State University were seen in follow-up at a mean of 31 months (range, 14-63 months) after their laminectomy and were evaluated by questionnaire, detailed neurologic examination, and static and dynamic lumbar radiographs. Thirteen patients who had undergone fusion or who had extenuating medical circumstances were excluded, leaving 24 patients for whom laminectomy was the sole treatment for lumbar stenosis. Postoperatively, normal walking improved from 4 to 45% of patients, sensory deficits decreased from 63 to 25%, and ability to perform most or all desired activities increased from 25 to 70%. Urinary function was unchanged. Thirteen patients (54%) showed radiographic signs of instability. All patients who were declared radiographically stable could walk without a prosthetic aid or normally; 62% of the unstable patients required aid for walking. All of the patients with a poor ambulatory outcome were radiographically unstable. Compared with stable patients, unstable patients had a significant (p < 0.01) decrease in their ambulatory ability. There was a clear correlation between the degree of listhesis and postoperative ambulatory status (p < 0.01). The unstable patients with a poor ambulatory outcome followed one of three clinical courses: improvement with later deterioration, improvement with a plateau at a poor functional level, or failure to improve from a poor functional level. In conclusion, (a) although instability did not necessarily preclude a good outcome, a poor ambulatory outcome was always associated with instability; (b) laminectomy can effectively ameliorate the symptoms of lumbar stenosis; however, there is a subset of patients in whom laminectomy is associated with instability and a poor clinical course.