The Effect of Minimally Invasive Spinal Procedures on the Orthotic Management of the Spine

New surgical techniques have transformed spine surgery in the last several years with technical advances that include laproscopic anterior fusions, Interthecal (thermal) procedures, kyphoplasty, artificial disk replacements, and others. With these new procedures, there is less soft tissue disruption, reducing the need for custom molded orthoses in many cases. Orthotic management is determined based on the specific surgical procedure, and prefabricated options are often considered the most appropriate. Patients who have undergone lumbar anterior disk replacement surgery, for instance, can benefit from an orthosis that blocks spinal extension but allows flexion, since excessive extension can anteriorally disrupt the new disk.

One of the minimally invasive procedures is called Lumbar Endoscopic Discectomy (LED). This is an outpatient procedure that removes herniated disc material from the spine. Using a video endoscope and xray guidance, a specially designed probe with less than 1/8" diameter is inserted through the skin, between the vertebrae, and into the herniated disc space. The herniated material is removed with laser, mechanical means, or suction and has the effect of lowering the intradiscal pressure. The incision is quite small compared to an open procedure, and the recovery period is shorter than after traditional surgery. Occasionally a microdiscectomy (MD) is performed along with the LED or IDET procedures when patients have more than 1 level involvement.

Intradiscal Electrothermal Therapy (IDET) or Laser Thermo Diskplasty are minimally invasive procedures that incorporate heat introduced through a probe. The heat tightens or shrinks the tissue exuding from the disc, and relieves the pressure on the spinal nerves. When there is an annular tear in a lumbar disc, the degenerative disk is removed, exposing the annular tear to the probe. Patients are under conscious sedation for the procedure, minimizing the post-operative effects of the anesthesia. (1)

Kyphoplasty is a procedure developed for the minimally invasive repair osteoporotic fractures of the vertebral body caused by osteoporosis or multiple myeloma. The surgery requires only a very small incision in the back. A narrow tube is inserted through the incision using fluoroscopy, which helps guide the tube into the damaged vertebrae. The physician then guides a special balloon into the vertebral body, using the tube as a channel. The balloon is inflated, creating a cavity in the vertebral body and restoring the vertebrae to a more normal shape. The balloon is then removed, and special instruments are used to fill the cavity with a soft, cement-like material, which hardens to stabilize the vertebrae. With the vertebral height restored, the structural stability of the disc is restored, the pressure on the nerves is reduced, and pain is relieved. The patient is immediately stable and does not require an orthosis post-operatively. (2)

Video assisted thoracic surgery (VATS) is a minimally invasive, keyhole procedure, which is an alternative to open thoracic procedures, requiring a large opening in the chest wall. Three or four small incisions allow the surgeon to use an endoscope and video camera to project pictures of the chest cavity onto a screen during the procedure. The surgeon can remove thoracic discs, biopsy vertebral tumors, release scoliotic curves, bone graft disc spaces, and even use instrumentation to stabilize the spine. This is accomplished through three or four keyhole incisions. (3)

Proponents of minimally invasive spine surgery (MISS) indicate that the procedure offers the same benefits as traditional spine surgery, with much less trauma. The incisions are very small, causing less soft tissue damage, and the procedures do not require the surgeon to retract the major muscles of the back. Patients are also spared the pain of deep soft tissue disruption and scarring. Less anesthesia is used, and hospitalization stays are dramatically shorted. Many patients go home the day of surgery compared to 3-5 day hospitalizations for more open procedures. Patients often return to work or leisure time activities within weeks of their surgery.

Less soft tissue damage translates into a need for less orthotic intervention. Since the muscles and tendons have not been disrupted as much, less external stability is required from the orthosis. Typically, physicians who use orthoses following MISS procedures want specific motions blocked without limiting motion in other planes. Since patients generally have few activity restrictions post-op, the orthoses need to be fit immediately to provide pain relief and stability for activities of daily living and return to function.

MISS procedures are continuously evolving, and physicians attend courses to learn how to implement the latest techniques. Since cervical through lumbar procedures are now addressed through MISS, a variety of orthoses need to be available to address the specific needs of the patient, physician, and procedure. A pre-fabricated spinal component system is available that allows anterior and posterior components to be interchanged, creating hundreds of potential combinations.¹ A thorough understanding of the procedure is essential for planning the appropriate orthotic intervention for each patient and procedure.

¹The Plug and Play Spinal System, Orthomerica Products, Inc.

References

1. www.aplusces.com/idetprocedure.html. 2005

2. Majd ME, Farley S, Holt RT."Preliminary outcomes and efficacy of the first 360 consecutive kyphoplasties for the treatment of painful osteoporotic vertebral compression fractures". Spine Journal 5:244-255. 2005.

3. www.spinesource.com/Back-Pain-Disorders/thoracic-disc-herniation.html. 2005