Post-traumatic syringomyelias

129 Post-traumatic syringomyelias with special regard to long-term-results >5-16 years after operation

Neurochirurgische Universitätsklinik Heidelberg

Aschoff A, Kaps H, Spahn B, Nanassy A, Freund M, Gerner W, Kunze St Introduction: Traumatic paraplegic patients, especially with tetraplegia, had a short life-exspectancy before the sixties. Long-term-complications such as cystic myelopathies were rarities. The modern paraplegological treatment led to a normal life-exspectancy resulting in a significant increase in post-traumatic syringomyelias (long-term-risk up to 21%, Wang 96!). There are numerous series in the literature, but most of these are small, include varying operative techniques and have short follow-up periodes (<3 years).

Material: The Heidelberg sample of 402 syrinx/Chiari-patients includes 129 with a post-traumatic syringomyelia or cystic lesions confirmed by MRI; 11 cysts ascended into the medulla oblongata. The patients presented with new syrinx-associated symptoms 3 months to 36 years after the original spinal trauma. 60 patients were operated in our hospital, 4 in other institutions. The follow-up was 10 to 16 years in 9 cases and 5 to 10 years in 24 patients. In 50 cases the primary treatment was a syringo-subarachnoid shunt (SSA) using micro-T-catheters (external diameter 1.3 mm), usually placed after hemilaminectomies guided by intraoperative sonography. In a few cases of severe arachnoiditis we favoured primary decompressive duraplasties (3), syringo-peritoneal shunts (SP, 3) or orthopedic stablizations (2). In 14 patients 31 revisions were necessary: 16 SSAs, 9 SP-shunts, 3 decompressions and 3 other.

Results: Complications were 1 CSF-infection, 1 intramedullary bleed (2x3 mm), 3 CSF fistulas and 12 neurological deteriorations, 7 of them temporary and 5 persistent. - Of the 33 patients with a long-term (>5 years) follow-up 7 (21%) reached a full and 7 a partial remission, related to the neurological level before the onset of syringomyelia, 12 (36%) showed a stablilization of their formerly progressive myelopathy. In contrast to these 79% more or less successful cases 5 patients (15%) had a significant and 2 (6%) a severe deterioration in the course of time. The short-term-patients (<5 years) had better results. - The decompressive duroplasty, proposed by Oldfield and Williams, and used in 6 patients, failed in 3 cases. In one patient an orthopedic correction of an ankylosing traumatic stenosis of the thoracic vertebra led to a full remission of a syrinx without any other measures.

Discussion: Some authors stress the importance of septae and recommend endoscopic perforations. We saw 3 post-endoscopic patients from another institution, 2 with massive new deficits: none of these patients was successfully treated. Our experience (confirmed by >1000 literature cases) shows, that a longitudinal intrasyringeal communication exists in >95% of cases in spite of marked septations or even completely interrupted syrinxes. High-risk procedures such as endoscopies should be reserved for a few selected cases. The real problems are as follows: 1. Is a prevention by orthopedic surgery possible? 2. In which cases can we treat the syrinx "causally", e.g. by restoring a normal spinal canal with free CSF flow (orthopedic correction, duraplasty, arachnolysis), and in which cases is it not successful? 3. Can we avoid iatrogenic lesions, (adhesions, tethering cord) during shunting using meticulous microsurgery and micro-catheters? Disappointing experiences with syrinx-shunts (Sgouros 95) may be the result of oversized tubes and overdrainage (pleural>peritoneal shunts).