LUMBOSACRAL SURGERY IN PATIENTS WITH CONGENITAL NERVE ROOT ANOMALIES

Abstract

Purpose: The presence of a congenital anomaly of the lumborsacral unit must be taken into consideration during the preoperative planning for lumbosacral surgery. We present our clinical and surgical experience, analysing the pre-, per- and postoperative aspects.

Material and methods: The clinical files,operative reports, and radiolographic results of 281 adult patients who had undergone lumbosacral surgery between March 1988 and January 2003 were analysed. Incomplete files were excluded. Clinical and radiological data were discordant in nine cases. These nine patients underwent extended laminectomy via a 3 cm posteromedial incision. Peroperative findings were noted with the Postacchini classification. Pain was assessed with a visual analogue scale.

Results: Mean age of the nine patients (five men) was 44.2 years (range 17–69). Mean follow-up was 22.3 months (range 2–48). The symptomatic roots were: L5 (n=2), L5–S1 (n=1), S1 (n=2) and S1–S2 (n=1). Lasegue sign was positive in all patients. An anomaly was identified on the preoperative radiograms in three patients. The anomalies observed intraoperatively were type I (n=1), type II (n=1), type III (n=6), type IV (n=1). In addition to the laminectomy discectomy was performed in six patients and factetectomy in two. The neurological structures presented significant resistance to medial displacement in all cases. Pain was scored 8.6 preoperatively (range 7–10) and 1.4 in the early postoperative period (rang 0–3). Pain worsened after six months (sacralgia).There were no neurological or infectious complications.

Discussion: For Kikuchi, presence of pain at two clinical levels can have four possible causes, nerve root anomalies being one of the potential causes. Aota proposed coronal MRI with fat suppression and Akbapak emphasised the need for ample exposure of the zone and pre-surgical diagnosis before percutaneous surgery to avoid catastrophic results.

Conclusion: Nerve root anomalies should be suspected when the clinical presentation is in disagreement with the radiological findings. Frontal or oblique MR imaging should be obtained. Likewise, intraoperative resistance of the neurological structures is suggestive of nerve root anomalies. Unless identified before lumbosacral surgery, the presence of nerve root anomalies may lead to irreparable neurological damage, particularly for minimally invasive or percutaneous procedures.