Microsurgical reoperation following lumbar disc surgery. Timing, surgical findings, and outcome in 92 patients.

Ninety-two patients who underwent microsurgical reoperation for persistent or new complaints following initial lumbar intervertebral disc surgery were evaluated retrospectively. Sixty percent of all pain relapses occurred within 1 year following the first operation; thereafter, the probability of a relapse declined steadily and was as low as 0.1% per year between 5 and 20 years. The results of microsurgical reoperation in terms of pain relief and working capability were considered "excellent" in 22% of patients, "good" in 30%, and "satisfactory" in 29%. Thus, 81% of the patients could be considered as treated successfully and in 19% the result was not successful. The most common intraoperative findings were: a true recurrence at the same level in 43% of cases, a new herniation at another level in 15%, and a small recurrent fragment embedded in epidural fibrosis in 23%. Five percent of patients had severe epidural fibrosis as the only pathology. In 15%, reoperation was performed within 1 month to treat persisting pain, and either a missed disc fragment, an inadequately decompressed lateral recess, or an unrecognized second-level disc protrusion was found. The clinical outcome is affected predominantly by the intraoperative pathology and the time interval between the first and second operation. An excellent or good outcome was usually achieved in patients with a recurrence of pain after 1 year resulting from a true recurrent disc or a new herniation at another level. In contrast, very unfavorable results were noted with most reoperations performed during the 1st year when extensive epidural fibrosis (or fibrosis with a small recurrence) was present.