Re-exploration of the lumbar spine following simple discectomy: a review of 23 cases

Summary

A retrospective study of 23 patients is presented, all of whom complained of recurrent symptoms of back and leg pain following simple discectomy. Five patients (22%) had been refused further surgery by the original surgeon on the grounds that they were psychologically disturbed. On examining the clinical records, 18 patients were reported to have had frank disc prolapses found at operation. In 5 cases, disc tissues were removed even though disc prolapses had not been demonstrated. Among the 18 patients in whom disc prolapses had been removed at their first operations, we found recurrent prolapses at reoperation in only 2 of them (11%). We treated 19 of these patients by nerve root canal and foraminal decompressions and 4 by anterior lumbar interbody fusion operations. The mean follow-up period was 34 months. Satisfactory relief of symptoms was achieved in 21 cases. In the published literature, even after the advent of CT and MRI, the incidence of recurrent disc prolapse at reoperation varies markedly from author to author. The reasons for these differences are discussed. They appear to relate to three factors: 1. failure to differentiate acute disc prolapse from annular bulging which develops and is inevitably associated with disc space narrowing; 2. difficulty in distinguishing between MRI findings of scar tissue enhancement and local perineural ocdema due to persisting foraminal and nerve root canal stenosis; 3. failure to identify the existence of foraminal stenosis, which is sometimes demonstrated only in oblique plain X-rays showing facet hypertrophy and subluxations of zygapophyseal joints. We conclude that, after careful selection of patients and assessment of pre-operative imaging studies, foraminal and nerve root canal decompressions that restore the perineural venous circulation in the lumbar spine will result in satisfactory relief of symptoms in the majority of patients who present with recurrent or persistent leg pains following simple discectomy and that spinal fusion is indicated in only a few cases.