To Home Page of PHI website to PHI's Secure Shopping Cart
PHI's Education
About PHI Education Advocacy Research Networking to How to Donate to Membership Application

Post-Polio Health (ISSN 1066-5331) (continued)

Vol. 11, No. 3, Summer 1995
Presented at Sixth International Post-Polio and Independent Living Conference

Post-Polio Corrective Spinal Surgery Now

Irwin M. Siegel, MD, Associate Professor of the Department of Orthopedics, Rush Presbyterian/St. Luke's Medical Center, Chicago, Illinois

Roughly one-third of all patients who have had poliomyelitis develop scoliosis (spinal curvature). This usually occurs early in the acute disease. No other scoliosis group benefits as much from spinal surgery as paralytic polio survivors. This is because they require a stable spine, balanced over a level pelvis, in order to stand and walk. A progressive curve of 50-60 degrees may indeed be an indication for correction and surgical stabilization. However, as with any operation, one can always make a patient worse if close attention is not paid to the specific conditions that must be met before surgery is undertaken. Among other things, these include cardiac and respiratory status adequate to survive the surgery, with close attention given to the special considerations of these operations in the post-polio patient.

The scoliotic curve in a polio survivor is usually long and may involve the thoracic as well as the lumbosacral spine. Trunk imbalance can cause an uneven pelvis, and the pelvis itself is often regarded as just another distal vertebra. Curves can increase after maturity, becoming painful if they have not been fused. Also, the patient can experience pain at the ends of a spinal fusion, where movement is usually increased to compensate for the loss of motion in the arthrodesed (fused) area of the spine. Ill-advised or overzealous spinal correction can cause serious loss of function, such as the ability to walk.

One alternative to surgery is bracing. The Milwaukee Brace (Polio Network News, Vol. 11, No. 2, p. 5) is an active orthosis requiring muscle strength and therefore usually not prescribed for a patient with neuromuscular disease. The TLSO (thoracic-lumbar-sacral orthosis) passively supports the back, usually producing better results.

Bracing is often indicated in the younger patient, but is also useful in the post-polio patient experiencing mechanical back pain. Light mesh garments (such as the Hoke garment) with stays are usually well tolerated. The fabrication of such a garment (which requires much patience and skill) is fast becoming a lost art. Consult your doctor, surf the network, search The Yellow Pages, or seek out an experienced orthotist who can provide you with a comfortable, functional appliance. For individuals using a wheelchair, various seating arrangements and spinal containment systems are available for back support. Modern techniques of vacuum molding can provide a custom-made seating system which should support the back and provide relief of pain. Seating assessments and recommendations are usually made by a physician working closely with an orthotist who specializes in seating.

The benefits of surgery include maintaining an upright posture, decreasing trunk fatigue and freeing the arms from a supporting role for more functional tasks such as dressing, eating, personal care or using a computer. Surgery may stabilize pulmonary function, avoiding respiratory compromise secondary to spinal deformity. However, one has to be cautious of increasing "dead space" with over-enthusiastic correction of spinal curvature. All of us have to push air in and out of our lungs from an area called the "dead space." This includes the trachea and the bronchi. We need muscle power to accomplish this.

Straightening the spine too much can increase the "dead space." When this occurs, the patient experiences difficulty moving air in and out of the additional space and may require mechanical ventilation to do so.

In planning for a major operation on a post-polio patient, there are some serious matters to be considered. Most important is a thorough respiratory examination (particularly in a patient with a history of bulbar polio). This workup should include blood gases and sleep studies. All prospective patients should have a good cough. Coughing requires the use of all respiratory musculature. Those patients with a poor cough may be unable to clear the pulmonary secretions that accumulate post-operatively.

In general, if the vital capacity is less than 30-35%, a patient will require post-operative respiratory aid. Where the vital capacity is somewhat above 60-70%, he or she should tolerate surgery well, except for obese patients or those with severe sleep disorders. The nutritional state of the patient is too often overlooked. Remember that protein depletion directly correlates with increased morbidity, compromised healing, impaired immunity and a greater risk of post-operative infection.

Finally, post-operative pain has to be considered. One theory holds that post-polio patients have increased sensitivity to pain, and some researchers feel that this is due to virus-induced brain lesions, as well as the anti-metabolic action of glucocortocoids on the brain produced during stress. Pain can be managed with anodynes, PCA (patient controlled anesthesia), and NSAIDs (non steroidal anti-inflammatory drugs), with care taken not to use medications which depress respiration.

Patients who have had polio are at more risk during surgery than those without such a history. Temperature has to be monitored because its decrease (hypothermia) can trigger cardiac arrhythmia. Hypotensive anesthesia coupled with blood loss may seriously lower blood pressure. Patients with neuromuscular disease undergoing surgery on their spines lose more blood than the average patient because they do not have muscles which can contract to block off small bleeding blood vessels. Their bone is often osteoporotic and will bleed copiously. Many people are overdosed on aspirin or other drugs which increase bleeding. These should be discontinued at least two weeks prior to any anticipated surgery.

Monitoring the spinal cord during the operation is important. Somato-sensory evoked potentials can be observed so that in straightening the curve further damage to the cord is avoided. Finally, at the time of surgery other contractures such as those of the hips, knees and ankles, can be released.

All of these matters should be taken into account prior to surgery as part of a detailed risks/benefits evaluation. Where the conditions as well as the indications for these operations are present, spinal stabilization performed by a skilled and experienced surgeon can often offer the post-polio patient correction of deformity, relief of pain, increase in the ability to perform tasks of daily living, improved mobility, and enhancement of lifestyle.

Continued ...