Minimal Access Surgery

In a nut shell what this means is doing the surgery through a very small incision. Modern technologies have been developed to allow surgeons to perform the same time honored procedures through smaller and smaller incisions. In general surgery, gallbladder and hernia surgery that used to keep patients in the hospital for days are now being done in the outpatient department with a fraction of the pain, faster recovery, and better outcomes. Spine surgery has undergone a similar transformation. Spine fusions and discectomies that used to require 3 to 6 inch incisions or more, are now done through small access tubes, under magnification. This has had the benefit of creating less soft tissue damage during the procedure, less blood loss and quicker recovery. In several instances, completely new techniques have evolved to take advantage of this new technology, allowing spine surgery to make tremendous advances over the last few years.

The TLIF technique is an example where several new technologies have come together to advance  the operation of spinal fusion years ahead in a very short time. TLIF stands for "transverse lumbar interbody fusion". In this technique small tubes known as Metrx tubes are inserted through the back muscles. By starting with very small tubes and sliding slightly large ones over the smaller ones in succession, the muscles are gently stretched rather than cut. The tubes allow access to the spine, where bone can be removed and lumbar disc access created. The disc is the large joint between each vertebra. By removing the disc through the tube, a fusion or bony union can be created where once there was only a painful disc.

This union does not just happen automatically. Traditionally, bone grafts were shaved off of the back of the pelvis and placed into the disc space. This created a rate of fusion near 90%, but it also created chronic, permanent pain at the bone graft donor site in up to 20% of patients. The next advance then was the commerical availability of a protein that stimulated bone growth. This class of proteins called bone morphogenic proteins (BMPs), were discovered in the late 1960s, but they could not be mass produced until relatively recently. It was the "osteoinductive" properties of these chemicals that resided within a patient's bone graft material that made them so effective in inducing fusion. By binding rhBMP2 to an absorbable sponge and placing this within disc spacer, the fusion rate was further enhanced without having to take bone grafts.

Lastly, it has been worked out that fusion rates are enhanced through the use of instrumentation. In most cases, the most effective instrumentation is called pedicle screws. There are several very ingenious methods of placing pedicle screws into the vertebrae above and below a fusion, holding it rigidly until fusion occurs. Much like a clamp one would use to glue two pieces of wood together, the fusion has its best chance of bringing between two vertebrae if they are held firmly by these devices for several months.  The methods of screw and rod insertion have been developed as companions to the minimal access fusion and can allow the placement of these devices through the same small incision made for the Metrx tubes. The Sextant system is such a device.

Pictured below is the Sextant Pedicle Screw system. It has advanced the placement of these devices in several ways. First, they are inserted through ever smaller incisions with all the advantages of decreased blood loss, pain and enhanced recovery seen with minimal access surgery. Second, they can be inserted usually considerably faster and with more precision than is possible through traditional open techniques. The Sextant system allows placement of these devices accurately with the use of fluoroscopy or moving X-ray rather than direct vision.

The confluence of minimal access visualization with Metrx, rhBMP to enhance fusion and avoid painful bone grafts, and Sextant to insert pedicle screws and rods to stabilize the fusion, allows the entire process to take about two to three hours per level and hospital days to be cut to two to three without the need for blood transfusion. All this with better fusion outcomes while preserving the spinal musculature.

                                                    Send mail to scooper@MemphisSpineCenter.com regarding all issues related to this website
                                                    Last modified: 04/04/06