Purpose: Today's surgeon faces many situations that require the reconstruction of bony defects of the cranial vault. Autologous bone is the traditional material used in these situations. They have low rates of extrusion and infection. However, autologous bone grafting has drawbacks such as donor site morbidity, longer operation times and increased resorption rates of the graft. Alloplastic materials for autologous bone are an appealing alternative. They are available in nearly unlimited supply and obviate donor site morbidity. One of the earliest alloplastic materials used in cranioplasty was Polymethylmethacrylate (PMMA), a malleable and inert implant material. More recently, biocompatible cements such as Hydroxyapetite cement (HAC) have gained acceptance. Our unsatisfactory experience with HAC has led us to return to PMMA in craniofacial reconstruction with excellent cosmetic and functional results as well as a low incidence of complications.
Methods: The Patients were evaluated and followed in the same Institute. The senior surgeon performed all procedures. The data presented is derived from a retrospective review of patient charts.
Results: Thirty patients, treated at the Institute for Craniofacial and Reconstructive Surgery, Southfield, Michigan, between the years 2000 and 2006, were included in the study. The mean postoperative follow-up was 2.1 years. Sixteen patients had full-thickness cranial defects, while the rest had partial-thickness defects. The etiology of the defects included trauma, congenital hypoplasia and tumor resection.
Table 1. Demographic Information Patients N % Mean Range Male 21 70% Female 09 30% <20 years 8 26.6% 13.2 3 to 19 21-35 years 6 20% 25.3 21 to 30 36-55 years 12 43.3% 44.8 36 to 55 >55 years 4 14% 71 61 to 81
Follow Up 30 100 2.1y 0.8yr- 4yr
Post-Traumatic Deformity - 12 Congenital Deformity -7 Tumor Resection - 9 Other -2 Full-Thickness 16 Partial-Thickness 14
Only one case was complicated by infection requiring removal of the implant. Three minor complications were encountered- exposure of implant material, hematoma, and seroma. These were successfully treated with secondary closure of minor implant exposure and expectant management of fluid collections.
Conclusion: Based on our series of 30 patients over an average follow-up of 2.1 years, PMMA is a safe and effective option for craniofacial reconstruction. PMMA may be used to create a reliable reconstruction comprised of an easily molded and biologically inert material. PMMA should not be used in tissues that have been infected within the past year, or in sites that communicate with the Paranasal sinuses. Graft immobilization via screw fixation in both full-thickness and partial thickness defects not only increases the stability of the reconstruction but also contributes to a reduced rate of peri-implant infection. Finally, it is probable that impregnation of the cement with Tobramycin has also contributed to a decline in infectious complications.