MIS Treatment of Adult Lumbar Degenerative Scoliosis

Printer Friendly Version

The spine becomes susceptible to degenerative changes during normal aging.  Biochemical changes, wear and tear, congenital disorders, childhood scoliosis, prior injuries, or metabolic diseases can contribute to spinal degeneration and alter spinal biomechanics.  Common disorders such as spinal stenosis, degenerative disc disease, osteoporosis, and vertebral compression fractures affect the integrity and stability of spinal structures and may cause lumbar degenerative scoliosis.
 

Scoliosis causes the spine to curve abnormally to the left or right.  The curvature may remain stable or progress and cause the spine to rotate.  Because the causes of adult lumbar degenerative scoliosis are broad, diagnosis by a spine surgeon skilled in minimally invasive surgery (MIS) is essential.

Diagnosis

The patient’s medical history, physical and neurological examination, and imaging studies are important to make an accurate diagnosis.

Medical history includes family history of scoliosis, the patient’s symptoms, severity, and treatments the patient has tried and the results.

Physical and neurological examination includes evaluating movement limitations, balance problems, pain, extremity reflexes, muscle weakness, and sensation.  The exam may include a series of movements such as bending sideways, forward and backward at the waist, and walking.

Imaging studies may include standing X-rays (front, back, side).  Side-bending X-rays are sometimes helpful to evaluate spinal flexibility. In addition, if necessary, a CT scan, MRI, or myelography may be performed.

When MIS is Recommended

Besides curve severity and symptoms, there are other considerations before surgery is recommended, if at all.  Although the indications for surgery may vary depending on the patient’s age and condition, MIS in general may be considered, if:

• Imaging tests demonstrate spinal instability, large curve, or curve progression
• Pain and other symptoms worsen and are unresponsive to nonoperative treatment
• Neurologic problems develop, such as bowel or bladder dysfunction

MIS Goals

Surgical goals include:

• Stabilize the spine, prevent curve progression
• Decompress spinal nerves (relieve nerve pressure)
• Treat deformity

Surgery may include combined procedures such as decompression, fusion, instrumentation, and deformity correction. 

Decompression procedures relieve pressure on spinal nerves.  Discectomy (disc removal), laminotomy, laminectomy, and foraminotomy are common procedures. Laminotomy (partial removal) and laminectomy (complete removal) involve removing the vertebral body’s lamina to increase the size of the spinal canal.  The lamina is a section of bone near each facet joint covering access to the spinal canal. Foraminotomy expands the foramen or spinal nerve passageways.

Spinal fusion uses bone graft to fuse or join two or more vertebrae.  Fusion is often combined with instrumentation, such as interbody devices (e.g., cage), pedicle screws and rods, to immediately stabilize the spine until the construct fuses.

Deformity correction involves restoring the spine to a more normal alignment and fixing the spine in position using fusion and instrumentation.

MIS Treatment

Minimally invasive spine surgery can approach the spine from the front (anterior), back (posterior), side (lateral), or back and side (posterolateral). Procedures such as those listed below share the same surgical goals:

• Direct Lateral Interbody Fusion (DLIF)
• Guided Lumbar Interbody Fusion (GLIF)
• Extreme Lateral Interbody Fusion (XLIF)

The interbody device, such as a titanium cage or PolyEtherEther Ketone (PEEK) spacer, is implanted into the disc space.  Bone graft is packed into and around the device to stimulate spinal fusion.  

DLIF provides access to the spine through the side of the body.  This procedure involves a transpsoas approach, which means the surgeon accesses the spine through the psoas muscle; a long muscle on both sides of the lumbar spine.

GLIF allows the surgeon to access the lumbar region of the spine through the side (laterally). This is a new procedure which allows the surgeons to perform surgery without having to reposition the patient.

XLIF accesses the spine through small posterior incisions between the ribs and hip.  This procedure treats L1 to L5 and is not effective for L5-S1.  Because XLIF does not affect supporting spinal structures, such as the ligaments, posterior instrumentation may not be needed.

Risks and Complications

Although the risks and complications of MIS are similar to open surgery, MIS may offer significant benefits to the patient.  Potential benefits include:

• Less postoperative pain
• Quicker recovery
• Reduced blood loss
• Minimized tissue damage
• Smaller surgical incisions (more cosmetically appealing)
• Less scarring
• Improved function

Of course, no patients are identical and risks and complications vary.  The best source of information for anyone considering MIS for adult degenerative scoliosis is a spinal surgeon. Not all patients are appropriate candidates for MIS correction of scoliosis and some patients do not require surgery.