demonstrate the many options available for exposure andreconstruction using this technique.

A transfrontal approach to the anterior and posteriorcomponents of the anterior cranial fossa are required withcertain pathological conditions and traumatic injuries. Themultiple uses of vascularized pericranial, free pericranial,and temporalis muscle flaps will be demonstrated.

The sequencing of this surgical clinic will be:1. Cranial base conditions—diseases—pathology2. Patient evaluation3. Presurgical preparation4. Surgical technique and instrumentation5. Postoperative care6. Long-term follow-up

Cranial base access surgery allows an extended rolefor the oral and maxillofacial surgeon.

References

Grime PD, et al: Transfacial access for neurosurgical procedures: Anextended role for the maxillofacial surgeon. Int J Oral Maxillofac Surg20:285, 1991

Uttley D, et al: Surgical management of midline skull base tumors. Anew approach. J Neurosurg 71:705, 1989

Dilorenzo N: Transoral approach to extradural lesions of the lowerclivus and upper cervical spine: An experience of 19 cases. Neurosur-gery 24:37, 1989

S420Alloplastic Temporomandibular JointReplacementPeter Quinn, DMD, MD, Philadelphia, PA

The alloplastic reconstruction of the temporomandib-ular joint is a unique challenge, especially in the multi-operated patient. The accepted indications for alloplas-tic joint reconstruction include:

• Ankylosed degenerated resorbed joints with se-vere anatomic discrepancies

• Failed autogenous grafts, especially in the multi-operated patient, with a scarred, poorly vascular-ized tissue bed

• Severe polyarticular inflammatory joint diseaseaffecting the TMJ

• Destruction of an autogenous bone graft by pre-existing foreign-body reactions to explanted allo-plastic materials

• Failed previous alloplastic reconstruction• Recurrent ankylosis with a history of excessive

heterotopic bone formationContraindications to alloplastic joint reconstruction include

allergy to prosthetic materials, chronic infection, skeletal im-maturity, and systemic disease that might increase the suscep-tibility to infection (for example, diabetes or myelodysplasia).My presentation will include a historical review of past sys-tems to establish biomaterial principles of reconstruction ofthis unique ginglymoarthroidal joint.

We will present 8-year data on a stock alloplastic jointsystem developed by Lorenz. Management of complica-tions and pertinent anatomy for adequate surgical expo-sure will be extensively discussed.

References

Mercuri LG: Alloplastic temporomandibular joint reconstruction.Oral Surg Oral Med Oral Pathol 85:631, 1998

Quinn PD: Alloplastic reconstruction of the temporomandibularjoint. Selected Reading Oral Maxillofac Surg 7(5).

van Loon J, et al: Evaluation of temporomandibular joint prostheses.J Oral Maxillofac Surg 53:984, 1995

S421Guided Tissue Regeneration in JawReconstruction: Review and ApplicationPamela Alberto, DMD, Sparta, NJ

In 1982, a group of researchers reported that tissueslost to periodontal disease could be regenerated by theuse of a surgical technique known as guided tissue re-generation. Since then, tremendous progress has beenmade in adapting these techniques to jaw reconstruc-tion. Along with the development of guided tissue re-generation procedures came the development of manyfirst-generation and second-generation membrane barri-ers.

The current first-generation barriers available areGore-Tex and TefGen. Both are made from 100% medi-cal-grade polytetrafluoroethylene (e-PTFE), but differ inthat TefGen is full density and is impervious to bacteria.Gore-Tex is expanded e-PTFE with pores. The biodegrad-able second-generation membrane barriers available areVicryl, BioMend, BioGide, OsseoQuest, and Capset. Vic-ryl Mesh is composed of woven polyglactin 910. Thepore size allows passage of fluids. It is resorbed in 2 to 6months. BioMend is fabricated from type I collagen de-rived from bovine deep flexor tendon. It is completelyresorbed in 4 to 8 weeks. The material must be hydratedin sterile water or saline for approximately 15 minutesbefore final placements. BioGide is composed of colla-gen types I and II in a bilayer membrane. It resorbs in 4months. OsseoQuest is a barrier made of polyglycolicacid and polylactic acid with trimethylene carbonate. Itresorbs in 6 months. Capset is composed of calciumsulfate. It must be used in conjunction with bone graft-ing material. It remains in the tissues for up to 30 days.

All have been used in clinical studies with varyingsuccess. A critical point for success of second-generationmembranes is the rate of degradation. The longer thematerial maintains barrier function, the better the re-sults. Thus, bioabsorbables may not perform as well asnonabsorbables. A study performed by Sandberg, Dahlin,and Linde found bioabsorbable membranes to be asefficient as e-PTFE and a valid alternative.

Surgical Clinics

134 AAOMS • 2003