Minimally Invasive Surgery

Posterior Instrumented Fusion with Sextant(tm)

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Spinal Fusion Animation
 

Posterior Instrumented Fusion with Sextant™ is an operation that involves approaching the spine through an incision in the abdomen. A portion of the affected disc space is removed from the spine and replaced with an implant and bone graft. In some patients, new technology allows surgeons to use Bone Morphogenetic Proteins as bone graft material instead of harvesting bone from the patient. This shortens operative time and eliminates pain from the bone graft site. The anterior incision is closed and the patient is then positioned in the prone position (laying face down on a padded frame). Small incisions are then made to insert the Sextant(tm) system. The Sextant(tm) system is a minimally invasive pedicle screw system that allows the surgeon to place pedicle screws with minimal disruption to the supporting musculature of the spine. Titanium screws and rods are inserted into the back of the spine to supplement the stability of the entire construct. Traditional surgery can damage the blood and nerve supply to muscles of the spine. Using minimally invasive screw systems such as the Sextant(tm) system allows for a stable spine with out the need for a brace in the post-operative period. The video demonstrates insertion of the Sextant system.

The SEXTANT™ System was designed in order to allow surgeons to connect percutaneously inserted pedicle screws along the posterior aspect of the spine with a rigid rod in order to stabilize the intervening motion segments. This accomplishes the same goals as placing pedicle screw-based spinal instrumentation in the posterior aspect of the spine via a conventional "open" exposure. However, this System has been designed to permit this type of instrumentation without an extensive surgical exposure, which minimizes the amount of damage done to the muscles, ligaments, and fascia of the back. This may offer significant advantages in terms of improved pain relief after spine surgery and decreased scar tissue formation in the spina erecta muscles. Recovery after major spinal surgery can be very difficult, and several studies have shown that an extensive surgical exposure and prolonged periods of retraction can seriously injure the major muscles of the back. This may have long-term consequences in terms of full recovery after spine surgery and regaining the muscle endurance that is a natural part of a healthy back.

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The System uses very small incisions, which limits the amount of trauma to the surrounding tissues, but this technique also limits what type of surgery can be performed on the spine. With a percutaneous pedicle screw technique, direct decompression of the neural elements cannot be accomplished. Some decompression of the neural elements is possible by distracting one vertebral body with respect to the other body with this system. However, the surgeon is not able to physically feel how much space is available for the spinal cord and exiting nerve roots. Therefore, a fusion must be the primary goal of a surgical procedure using the System, and direct decompression of the neural elements via a posterior approach must be unnecessary. There are several spinal disorders that may be amenable to this type of treatment, including certain types of spondylolisthesis, pseudoarthrosis after an anterior interbody fusion or an un-instrumented posterior spinal fusion, and also when certain types of posterior spinal instrumentation is used to augment an anterior interbody fusion.