Selective

DORSAL RHIZOTOMY

by Rick Abbott, M.D.

Selective dorsal rhizotomy (SDR, also called functional dorsal rhizotomy) is a neurosurgical technique to treat spasticity, especially in children with cerebral palsy. This procedure which evolved from work in the late nineteenth centruy, is based on the assumption that spasticity results from loss of the moderating influences of nerves, from the brain on the spinal cord's many relflex circuits, SDR can perminately relieve spasticity in the legs. With therapy, walking may be improved; sometimes, spasticity affecting the arms may also improve, as many abilities for activities of daoily living (ADL's)

Evaluation

SDR is "selective" because the surgeon selects appropriate rootlets to be cut and because not all individuals with spasticity should undergo this proceedure. There are two broad categories of canadidates;

1. individuals, limited in performing activies by their spasticity, with sufficient underlying voluntary power to maintain and eventually improve their abilities once spasticity is alleviated. They also need to be able to understand the importance of actively participating in therapy;
2. individuals, unable to walk, for whom spasticity intereferes with sitting, bathing, positioning and general caretaking. Individuals with spasticity are also considered for SDR if their spaisticity is so severe that it causes painful hip dislocation and bony deformities that cannot be repaired via orthopedic surgery. However, if an individual needs his/her spasticity to stand or walk, then treatment may impair funtion and not be advisable.

Surgery

During SDR surgery, the sensory nerve roots, which run from the spastic leg muscles to the spinal cord, are separated from the motor nerve roots and stimulated electrically. Leg muscles are observed for contraction ba a clinician using an EMG ( an electrical device which records muscle contraction). Individual roots that cause abnormal contraction are separated into their component rootlets which, in turn, are stimulated. Abnormally responding roolets are cut.

In most cases, the majority of rootlets respond abnormally. The neurosurgeon decides how many may be cut without creating a sensory deficit. The proceedure takes four to eight hours or longer.

Because of some children's vulnerability to muscle spasms, the pain and discomfort associated with SDR can be severe for two to three days. Accordingly, high doses of narcotics may be delivered directly into the wound via the catherers left in the surgical site.

For three or four days after the operation, the child is confined to bed, lying on his or her stomach. The child will feel sleepy and weak, especially in the legs. After about 10 days, the stiches are removed and the child can be transported in a wheelchair.

For a child with potential to improve functional abilities, intensive therapy begins while the child is still in bed.

After about a month, the child can return to regular activities; intensive therapy (four or more hours each week) continues. After three months, therapy is required two to three hours each week. Whenever possible, physical therapy is supplemented by parental help in stretching and stregthening activities.

After SDR, children soon discover that their bodies are operating under different rules. The difference is similar to the way an automobile handles after a driver discovers she or he has been driving with the brake engaged and releases it. Therapy is essential in the postoperative period because the child needs to "re-learn" body control.

During the first six to nine months following SDR, significant improvement is seen. Some children continue to improve for several years.

SDR usually decreases spasticity; however, functional abilities do not always improve.

Side effects and complications

Side effects and complications during the procedure can include: asthma attacks- especially in children with a history of asthma, bronchitis or recent upper respiratory tract infection- and vomiting into the lungs.

Side effects and complications after the procedure can include: temporary trunk weakness; an increase in muscle tone associated with severe pain at the site of the incision and spasms lasting as long as 48 hrs; temporary inability to urinate (sometimes requiring bladder cathererization); temporary ( one to four weeks) "pins and needles" sensation in the legs, and small areas of permanent numbness in the legs.

Lon-term complications are also being recognized. Hip dislocations have occured in a small number of individuals-typically in those who were unable to walk prior to surgery and who had a lot of hip and pelvic instability due to weakness of hip musculature. (Hip dislocations also occur in individuals who do not undergo rhizotomies.) Many children have experience loss of available range of motion (ROM) in their knee and ankle joins after initial improvement, even though their improved tone remains. This deterioration in ROM may reflect inadequate stretching of the muscle groups (resulting in contractures) during the growth spurt. This complication can mean the need for ongoing therapy.

SDR does not replace the need for physcial therapy; it may actually increase it to the degree that the child's potential abilities increase. Some have been concerned about the possibility of scoliosis (spine curvature) after SDR. However, there have been no reports that the risk of scoliosis has increased using current procedures.

Long-term results

Children with various degrees of leg spasticity (able to walk, able to cral, unable to walk or crawl) have significant improvement in the tone of every muscle tested. Also, preoperative functional goals set by the clinical team are met more than 80 percent of the time. However, it is becoming apparent that SDR is not a procedure guaranteed to prevent the need for further surgery. Some may eventually require hip surgery due to significant hip dislocation. Some may require tendon surgery to increase limited range in a joint.

credit for this article goes to Rick Abbott, M.D. and Exceptional parent Magazine.

[Hit Counter]

This site designed & maintained by D Angel's Web Design & Graphics. The Cerebral Palsy Network©1997/98. All graphics are the exclusive property of CPN, unless otherwise indicated. Contact CPN at info@cp-network.org for further information.

Last updated  10/31/99