Resorbable implants advance craniofacial surgery

Originally Published MPMN March 2002

SPECIAL

Resorbable implants advance craniofacial surgery

Craniofacial surgery can greatly improve the lives of patients with abnormalities. The invention of a new product can not only ensure that these procedures achieve dramatic results in correcting deformities, but also solve problems than can arise when traditional methods are used.

Until now, surgeons have used metal implants to reconstruct and repair facial bones. Although the surgeries are generally successful, there are drawbacks to the use of metal. The most significant is that it must be removed after the bones have healed. This exposes the patient to another surgery, which always poses a risk. Additionally, scatter artifact of the metal plates obscures the surgical field in MRI and CT scans, and the presence of metal can complicate tumor treatment.

A product that is strong enough to hold bones together while they are mending, yet completely resorbs into the body when healing is complete, would be the answer to these problems. Realizing the promise of such a substance, two plastic surgeons in San Diego, Steven R. Cohen, MD, and Ralph E. Holmes, MD, and members of the craniomaxillofacial/neuro business unit of Macropore Biosurgery Inc. (San Diego; www.macropore.com), decided to team up. Their first project was to create a resorbable implant for a procedure used to correct the Crouzon's syndrome midface deformity in children.

Like many other craniofacial surgery procedures, the LeFort III distraction has required the use of titanium plates and screws to fix the facial structure. While this system has often worked, "patients spent long periods of time in external or internal metal devices," says Cohen. Additionally, according to Cohen, the plates and screws were difficult to remove after completion of the procedure.

The partnership came up with a resorbable distraction system that is manufactured from a medical-grade 100% amorphous polylactic acid copolymer 70:30 Poly(L-lactide-co-D, L-lactide), which retains approximately 70% of its initial strength after 9 months and 50% after 12 months. The implants metabolize into carbon dioxide and water following a process of bulk hydrolysis and resorb completely in approximately 18 to 36 months. This eliminates the need for removal procedures while avoiding long-term palpability and ambient-temperature sensitivity.

"The use of bioresorbable materials in medicine has great potential," says Cohen. "Some of the uses I anticipate include drug delivery, stem-cell container devices, ear shunts, soft-tissue reconstruction in ear and nasal passages, coronary artery stents, and treatment of burn victims."

Benjamin Lichtman, Norbert Sparrow, Katherine Sweeny, Zachary Turke, and Susan Wallace

Copyright ©2002 Medical Product Manufacturing News