Minimally Invasive Lumbar Surgery

Spine surgery is traditionally done as "open surgery," meaning the area being operated on is opened with a long incision to allow the surgeon to view and access the anatomy. In recent years, however, technological advances have allowed more back and neck conditions to be treated with a minimally invasive surgical technique.

Because minimally invasive spine surgery (MISS), does not involve a long incision, it avoids significant damage to the muscles surrounding the spine. In most cases, this results in less pain after surgery and a faster recovery.

Spine surgery is typically recommended only when a period of nonsurgical treatment — such as medications and physical therapy — has not relieved the painful symptoms caused by your back problem. In addition, surgery is only considered if your doctor can pinpoint the exact source of your pain, such as a herniated disk or spinal stenosis.

Minimally invasive techniques are beginning to be used for a wider range of spine procedures, and have been used for common procedures like decompression and spinal fusion since the 1990s. Decompression relieves pressure put on spinal nerves by removing portions of bone or a herniated disk. Spinal fusion corrects problems with the small bones of the spine (vertebrae). The basic idea is to fuse together the painful vertebrae so that they heal into a single, solid bone. This article focuses on decompression and fusion with a minimally invasive technique.

Description

Minimally invasive spine surgery (MISS) is sometimes called less invasive spine surgery. In these procedures, doctors use specialized instruments to access the spine through small incisions.

In a traditional, open surgery, the doctor makes an incision that is 5 to 6 in. long and moves the muscles to the side in order to see the spine. With the muscles pulled to the side, the surgeon can access the spine to remove diseased and damaged bone or intervertebral disks. The surgeon can also easily see to place screws, cages, and any bone graft materials necessary to stabilize the spinal bones and promote healing.

One of the major drawbacks of open surgery is that the pulling or "retraction" of the muscle can damage the soft tissue. Although the goal of muscle retraction is to help the surgeon see the problem area, it typically affects more anatomy than the surgeon requires. As a result, there is greater potential for muscle injury, and patients may have pain after surgery that is different from the back pain felt before surgery. This can lead to a lengthier recovery period.

Minimally invasive spine surgery was developed to treat spine problems with less injury to the muscles and other normal structures in the spine. It also helps the surgeon to see only where the problem exists in the spine. Other advantages to MISS include smaller incisions, less bleeding, and shorter stays in the hospital.

Although MISS holds advantages for many patients, it is important to note that some back and neck problems cannot yet be treated effectively with minimally invasive methods. In general, MISS procedures take less time than open procedures, however, depending upon patient needs, MISS may take longer to perform and require several incisions.

Procedure

MISS fusions and decompression procedures (such as diskectomy and laminectomy) are performed with special tools called tubular retractors. During the procedure, a small incision is made and the tubular retractor is inserted through the skin and soft tissues down to the spinal column. This creates a tunnel to the small area where the problem exists in the spine. The tubular retractor holds the muscles open and is kept in place throughout the procedure.

The surgeon accesses the spine using small instruments that fit through the center of the tubular retractor. Any bone or disk material that is removed exits through the retractor, and any devices necessary for fusion — such as screws or rods — are inserted through the retractor. Some surgeries require more than one retractor.

In order to see where to place the incision and insert the retractor, the surgeon is guided by fluoroscopy. This method displays real-time x-ray images of the patient's spine on a screen throughout the surgery. The surgeon also uses an operating microscope to magnify the view through the retractor.

At the end of the procedure, the tubular retractor is removed and the muscles return to original position. This limits the muscle damage that is more commonly seen in open surgeries.

The most common types of anesthesia used for MISS are general (you are asleep for the entire operation) and regional (you may be awake but have no feeling from your waist down).

Common Minimally Invasive Spine Surgeries

MIS Lumbar Diskectomy

A herniated disk in the lower back that pinches a nerve may cause severe leg pain, numbness, or weakness. To surgically relieve these symptoms, the disk is removed. This procedure is called a diskectomy.

For the surgery, the patient is positioned face-down and a small incision (sometimes less than 1 in.) is made over the location of the herniated disk. The surgeon inserts the retractor and removes a small amount of the lamina bone. This provides the surgeon with a view of the spinal nerve and the disk. The surgeon carefully retracts the nerve, removes the damaged disk, and replaces it with bone graft material.

This minimally invasive technique can also be used for herniated disks in the neck. The procedure is done through the back of the neck and called an MIS posterior cervical diskectomy.

MIS Lumbar Fusion

A standard, open lumbar fusion may be performed from the back, through the abdomen, or from the side. Minimally invasive lumbar fusions can be done the same way.

A common MISS fusion is the transforaminal lumbar interbody fusion (TLIF) Using this technique, the surgeon approaches the spine a little bit from the side, which reduces how much the spinal nerve must be moved.

In an MIS TLIF, the patient is positioned face-down and the surgeon places one retractor on either side of the spine. This approach prevents disruption of the midline ligaments and bone. Using the two retractors, the surgeon can remove the lamina and the disk, place the bone graft into the disk space, and place screws or rods to provide additional support.

Approaching the spine slightly from the side does not provide the surgeon with a full view and it is often a challenge to remove the disk completely. This may make fusion healing more difficult. Sometimes the surgeon will use additional bone

Source:  American Academy of Orthopaedic Surgeons 


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