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Post-Polio Health (ISSN 1066-5331)

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

Post-Polio Corrective Spinal Surgery Now

Ensor E. Transfeldt, MD, Twin City Scoliosis Spine Center, affiliated with Abbott Northwestern Hospital, University of Minnesota, Minneapolis, Minnesota

The Twin City Scoliosis Spine Center works in conjunction with the Sister Kenny Institute at Abbott Northwestern Hospital where Richard Owen, MD, has a special interest in post-polio problems.

A surgeon's job of actually doing surgery requires technical skills, but those technical skills are worth nothing without the team of people that assist in the care of the patient. We are treating people, not treating spines, so we need to consider other factors such as pelvic obliquity, limb deformities, ability to walk, pulmonary function, general medical condition and nutritional, immunologic and health status.

e also consider the mental and emotional well-being of a person undergoing surgery. Most deformity surgery is major surgery, and we cannot overemphasize that people need to be ready for the physical and emotional onslaught.

Patients with poliomyelitis are subject to the same conditions of degeneration as everyone else. They may undergo disc degeneration and even develop stenosis which may produce neurologic compression and confuse the diagnosis of a post-polio syndrome.

Scoliosis is a side-to-side curvature, but also a three dimensional deformity. Persons who from the side have an exaggerated hump have what we term a kyphosis. Persons who have an exaggerated hollow in the low back region have a lordosis.

Many times a rotation of the vertebrae is associated as well. The vertebrae do rotate on top of each other and on an x-ray may appear to show a straight spine, but, from another view, the rotation shows up. Attached to the vertebrae in the thoracic spine are the ribs, and as the vertebrae rotate the ribs rotate. The ribs produce the characteristic prominence, not the spine.

Another problem that develops is that the whole trunk gets shifted to one side. The body is not centered over the pelvis and the legs. This requires much more energy to stand or to walk.

The curve types resulting from polio do vary according to the area of the spine affected - the cervical, thoracic, or lumbar. The long C-shaped curve is very common. The original curve, called the primary curve, is usually due to an imbalance of the muscles. If that was the only curve, one would lean over to one side. There are muscles that are not paralyzed which try to compensate for this so the body is centered over the pelvis.

This results in compensatory curves usually on either side of a primary curve.

Sometimes, compensatory curves will progress and become fixed or structural curves. Frequently, it is important to operate early on a young person before the compensatory curves become structural curves.

Not a great deal is known about the natural history of scoliosis and poliomyelitis except that all curves progress. The pattern of progression in polio is certainly very different to idiopathic scoliosis in that the progression frequently occurs after skeletal maturity into adulthood. Early surgery is generally recommended in scoliosis for younger patients, but in adults there are other complicating factors.

Spinal surgery is considerably more difficult in polio than idiopathic scoliosis. For example, cosmetic correction tends to be successful in young patients. In adults, the results tend to be much more variable. The only way to produce any significant correction cosmetically is to remove the prominent ribs which are associated with rotation. This is associated with a higher morbidity, and patients need to be aware of that fact.

The indications for surgery are curve progression, pain associated with bad curves, and, if spinal stenosis or spinal compression is evident, decompression. The goals are to correct the deformity, stabilize the spine and produce a vertical torso or a body centered over the level pelvis.

Surgery of putting in implants and rods in patients with severe scoliosis is difficult. Disc spaces frequently become narrow and vertebrae become coalesced making it difficult to move them and create a correction.

Because pelvic obliquities and muscle contractures are common and complicate surgery, one needs to evaluate the presence and cause of pelvic obliquity. One must ask if the pelvic obliquity is because of the scoliosis or is it a result of something in the pelvis or something below the pelvis. Muscles go from the spine to the pelvis; from the spine to the lower legs, spanning right across the pelvis not attaching to it; muscles run from the pelvis to the lower legs. Any contractures, or imbalance, of any of the above muscle groups can result in a pelvic obliquity. One has to evaluate where the problem is - above the pelvis, in the pelvic region, or below the pelvis. One test is to lay the person on an x-ray table and move the pelvis to see how flexible the spine is at that level. If one can tilt the pelvis and create a level pelvis then the spine is flexible. One gentleman was recommended for surgery and this bending test showed a possible level pelvis. The problem was a muscle contracture of the iliotibial band below the pelvis which was corrected surgically by a simple release of the muscle.

Ambulatory status needs to be evaluated. Long fusions down to the pelvis could limit someone who walks with crutches and needs the mobility of the lower lumbar spine.

Pulmonary function needs to be evaluated. Pulmonary dysfunction may be due to respiratory muscle paralysis or mechanical obstruction. Decreased lung volume can be caused by the collapse of the thoracic spine, the rib cage pushing in on the pelvis, or the abdominal contents being pushed upwards. Breathing ability does not equate to the ability to tolerate surgery. Certain tests do indicate whether or not surgery may help. There is some controversy about pulmonary function studies, but a study done at Twin City Scoliosis Center showed that patients with severe cor pulmonale or severe pulmonary dysfunction can be considerably improved by pre-operative traction. The thoracic cage is pulled away from the pelvis and the diaphragm is allowed freer excursion.

There are several methods of instrumentation including newer methods using segmental instrumentation. Fixation at multiple levels of the spine really does eliminate the use for braces which in fact restrict chest expansion and affect pulmonary function. The type of instrumentation is not as important as the technique of the surgery and the judgments considered before surgery.

Complex problems need the team approach and that includes the physicians, the surgeons, the physiatrists, the therapists, the nurses, and a program of intense rehabilitation. The family is an integral part of the team and should be included during the decision-making process and fully understand what is going to occur.

Measuring Scoliosis Curves

x-ray showing scoliosis curveThe technique most often used to measure a curve was described by Dr. J.R. Cobb. The Cobb measurement is made by identifying the vertebrae at the ends of a scoliosis curve on an x-ray of the spine taken front to back, or back to front. A line is drawn along the upper border of the upper end vertebra, and along the lower border of the lower end vertebra. The angle between these lines is the Cobb measurement. An angle of 0 degrees means that the two vertebrae are at right angles to each other, signifying a severe curvature.

Excerpted from Back Talk, Vol. 17,/ Number 3/December 1994,
published by The Scoliosis Association, Inc., PO Box 811705, Boca Raton, FL 33481-1705

Scoliosis Resources:

National Scoliosis Foundation
5 Cabot Place, Stoughton, MA 02072
800-NSF-MYBACK (800-673-6922), 781-341-8333 fax
nsf@scoliosis.org, www.scoliosis.org

Scoliosis Research Society
555 E Wells St Ste 1100, Milwaukee, WI 53202-3823
414-289-9107, 414-276-3349 fax

The Scoliosis Association, Inc.
PO Box 811705, Boca Raton, FL 33481-1705
561-994-4435, 561-994-2455 fax
www.scoliosis-assoc.org

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