A technique for rigid fixation of methyl methacrylate cranioplasty: the vault-locking method

Abstract

BACKGROUND Current treatment of difficult to reach lesions of the central nervous system favors extensive bone removal for improved visualization and access with minimal brain retraction. Particularly in the posterior fossa, bone is often removed piecemeal, and a standard craniotomy flap is not always available for simple reattachment. Cranioplasty with methyl methacrylate is used to provide cosmesis and neural protection. A method for the fixation of methyl methacrylate cranioplasty is described, and the results of technique application in 30 patients during a 14-month period are reported. METHODS A series of notches are burred in the cancellous margin of the surrounding cranium, preserving the inner and outer tables. Methyl methacrylate is applied to the defect. Overflow of methyl methacrylate into the notches assures solid fixation. The resultant construct resembles the locking mechanism of a bank vault. No mesh, wire, or miniplates are required. Prolene buttresses may be placed through the outer table of the notches to identify their location, should removal of the plasty be required. Removal of the outer table over the notches facilitates rapid removal. RESULTS Solid plasty and good cosmesis occurred in all patients. There were no infections or complications related to this technique. CONCLUSIONS Firm fixation, molding and hardening in situ, and technical ease are potential advantages over established methods of cranioplasty.