The profile of multiple- versus single-operated patients at the time of their first operation for lumbar disc herniation

Abstract

A retrospective study was carried out on a total of 491 patients (294 male, 197 female) who underwent surgery between 1 January 1980 and 31 December 1986. They were treated by minimal intervention lumbar discectomy without the use of a microscope. The patient groups consisted of 241 patients who needed a second operation (MOP, multiple operations) and another 250 patients who needed only one surgical procedure (SOP, single operation) and the whole treatment period was between 1 January 1980 and 31 December 1990. The SOP patients served as control group. The MOP and SOP groups were compared in the search for clinical and/or morphological parameters which might distinguish the two groups at the time of first operation. In terms of history, age, sex distribution, pre-operative treatment and severity of neurological symptoms there was no statistical difference between the two groups at the time of the first operation. Radiological examinations were more extensive but less conclusive in the MOP group. In the SOP patients, subligamentous and epidural disc fragments occurred in 67.2% of patients. In the MOP patients disc protrusions or small subligamentous extrusions were predominant (50.1%) at the time of the first operation. Osteochondritic changes occurred less frequently in the MOP (39.1% vs 53.6%). There were significantly more two-level approaches in the MOP patients (31.5% vs 14.4%); also, the surgical technique in the MOP group was less invasive, often being 'explorative' in character. Post-operative morbidity was higher, improvement of neurological symptoms was slower and the overall result was worse in MOP patients after the first operation. Interpretation of radiological findings, disc morphology and surgical technique are usually considered factors influencing the outcome of disc surgery. At the second operation (MOP 2) there were epidural scars in 48.4% of patients and the incidence of disc fragments containing parts of the end-plate increased from 10.1% to 61.9%. The prognosis was worse in patients with mild pre-operative disc degeneration.