PROLAPSED DISC FRAGMENT TYPE AS A PREDICTOR OF RECURRENCE OF DISC HERNIATION OR SCIATICA.

Abstract

Introduction and Aims: Recurrent disc herniation or sciatica is one of the major complications of discectomy, often leading to a cascade of surgical procedures of increasing magnitude, but decreasing surgical outcome. We undertook a study to see if prolapsed disc fragment type can predict the possibility of recurrence of disc herniation or sciatica.

Method: We looked at the records of patients who had a discectomy operation during a 10-year period from 1992–2002. We excluded from the study patients who had a concomitant fusion operation, patients with multiple level disc operations and those who have diabetes. We went through the operation records, looking for the type of the disc fragment, i.e. whether it was contained, extruded or sequestrated disc. In the follow-up notes we recorded the patients that complained of leg pain, starting three months after the operation and continuing despite treatment. We recorded the length of follow-up.

Results: Sixty-five patients were entered for the study. There were 31 males and 34 females. The age range at surgery was 16–61 years (average 42.1 year). The follow-up ranged from 18 months to 10 years (average 30 months). We divided the patients into two groups. Group A, those patients with recurrent leg pain; and group B, those patients with no leg pain.

There were 18 patients in group A – they were all subjected to further examination with MRI scan. In five of the patients, the scan showed recurrence of disc herniation. It was an ipsilateral reherniation in four patients and contralateral in one patient. Eight of these 18 patients required repeat surgery.

In the five patients with reherniation (7.69% of whole series), the repeat surgery was a discectomy. In another three patients the surgery was a wide decompression and fusion. On further analysing the pathology found at the initial discectomy, in the group A patients, six (33%) had extruded discs and 12 (66%) had contained discs. In group B, 34 (72%) had extruded discs and 13 (27%) had contained discs. The statistical significance in this small series is debatable.

Conclusion: Patients with extruded discs do much better than those with contained discs. Recurrent disc herniation is more common in contained discs and less common in extruded discs. If we could select pre-operatively those patients with contained disc herniations, we could elect to persist with conservative treatment for longer in this group.