Abstract :
Introduction: In the literature various techniques have been described for the internal fixation of an unstable craniovertebral junction. A technique, ideal in terms of providing perfect stability for a sufficient period of time without any need of cumbersome external support, is yet to be established.
Method: In 200 cases, posterior fusion of an unstable craniovertebral junction was done with iliac crest bone graft and stainless steel wire. In situ moulded Polymethyl Methacrylate (PMMA) was applied as an additional internal splint at the fusion site. Moulded PMMA was anchored to the occiput so that its loosening and displacement could be prevented.
Results: In all 200 cases we found that PMMA reinforced the wire and bone graft fusion and thus obviated the need of postoperative external support e.g. Halo fixation, braces, traction or Plaster of Paris cast. It prevented cranial settling and no patient of reducible basilar invagination required subsequent anterior decompression. In this series complications occurred in the form of - infection in 2 patients, operative mortality in 1 patient, and operative injury to vertebral artery in 1 patient. Incidence of wire biting and breaking was nil.
Discussion and Conclusion: Although PMMA is not effective as a primary fusion material, however it can be used as a supportive immobilization device. We also conclude that PMMA can be made more effective by anchoring it with the fusion site.
