Surgeons perform the first posterior total disc replacement at a Brazilian hospital

The surgeons aligned the two-part implant with the patient’s instantaneous axis of rotation.

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Orthopaedic spine surgeons in Brazil and the United States recently collaborated on the first total disc replacement using the posterior approach.

Surgeons Luiz Pimenta, MD, PhD, of São Paulo, Brazil, and Paul C. McAfee, MD, of Towson, U.S.A., used the Secure-P [Globus Medical Inc.] in a patient who underwent the procedure at Santa Rita Hospital in São Paulo in March.

McAfee told Orthopaedics Today International that by implanting the device posteriorly, surgeons can avoid dissection of the great vessels and the need for a general surgeon to provide access to the spine. It also "obviates the requirement to dissect the retroperitoneal contents and eliminates the complication of retrograde ejaculation, which occurs in 3% of anterior procedures," he said.

The patient is a 47-year-old woman who was completely disabled with chronic degenerative disc disease at L4-L5. She had symptoms and indications substantial enough that she met the inclusion/exclusion criteria for the Charité and the ProDisc lumbar disc replacement investigational device exemption.

The patient stayed in the hospital for 2 days following her procedure and was walking with moderate pain upon discharge. At 1-week follow-up, she was fully ambulatory and neurologically  "intact," according to the surgeons.

Risks with posterior approach

Although the patient is doing well and "the posterior approach is one that 100% of spine surgeons have good skill at using," according to Pimenta, there are some challenges.

"The main challenge of the prosthesis is to be able to clean out the disc space and restore the disc space height without undue retraction of the lumbar nerve roots," McAfee said.

The Secure-P comes in two pieces. Once the implant is inserted into the disc, the pieces are placed opposite each other, with the nerves fixed in between.

Device construct

"For something to work and to move, it has to be aligned with the patient’s instantaneous axis of rotation (IAR)," McAfee said. "You do it by working around the nerve roots. The ingenious part is that the alignment system they use is a 3-D system, which is aligned with the patient’s IAR. That is what allows it to work."

The device is made of cobalt chrome and ultra-high-molecular-weight polyethylene and is designed to restore disc height and return the pattern of motion to neutral without compromising stability or neurological function, according to Pimenta.

Investigators will start a clinical trial with the Secure-P this summer.

For more information:

• Paul C. McAfee, MD, can be reached at O’Dea Medical Arts Building, Suite 104, 7505 Osler Drive, Towson, MD 21204, U.S.A.; +1-410-337-8888; fax: +1-410-823-4833; e-mail: mack8132@gmail.com. He is a consultant with Globus Medical Inc. and is on its medical board of directors.
• Luiz Pimenta, MD, PhD, can be reached at Santa Rita Hospital, Rua Borges Lagoa 783/61, São Paulo, Brazil; +55-11-55719933; fax: +55-11-55728912; e-mail: luizpimenta@hotmail.com. He is a consultant for Globus Medical Inc.
• McAfee PC, Pimenta L. Transformational (TLIF) and posterior (PLIF) approaches for the insertion of the Glopus lumbar arthroplasty system. Presented at Spine Arthroplasty Summit 7. May 1-4, 2007. Berlin.

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