Objectives: The recommended operative treatment against hindbrain related syringomyelia is suboccipital decompression. The aim of the study was to define prognostic factors for surgical outcome in this disease.
Materials and methods: Between 1990 and 1997, 31 patients with hindbrain related syringomyelia were treated. All patients underwent craniovertebral decompression by suboccipital craniectomy and laminectomy of C1 or C1 and C2, respectively. Additionally, in nearly half of the cases, the tonsils were treated by bipolar coagulation. Mean post-operative observation period was 35 months including clinical and radiological (MRI) examination.
Results: Neither there was correlation between clinical outcome and age nor correlation between clinical outcome and duration of preoperative symptoms. There was good correlation between clinical outcome and result of post-operative MRI: 63% of patients with a sufficient post-operative MRI demonstrated a significant clinical improvement, whereby only 17% of patients with insufficient MRI did so (P < 0.05). None of the patients with coagulation of the tonsils showed clinical improvement. In contrast, 77% of patients without tonsillar manipulation demonstrated clinical improvement (P < 0.01). Additionally, 88% of the patients with dorsal-tenting duraplasty experienced neurological improvement (P < 0.01), too.
Conclusions: The results give evidence for the prognostic importance of creating an adequate artificial cisterna magna. Dorsal-tenting of the duraplasty is an advantageous means against scarring and adhesions, whereby intradural applications such as extensive bipolar coagulation of the cerebellar tonsils should be avoided.