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What is SDR surgery?

Procedure Details

Selective Dorsal Rhizotomy (SDR) begins with a 1 to 2 inch incision along the center of the lower back just above the waist. An L1 Laminectom is then performed: a section of the spine's bone, the spinous processes together with a portion of the lamina, are removed, like a drain-cap, to expose the spinal cord and spinal nerves underneath. Ultrasound and an x-ray locate the tip of the spinal cord, where there is a natural separation between sensory and motor nerves. A rubber pad is then placed to separate the motor from the sensory nerves. The sensory nerve roots, each of which will be tested and selectively eliminated, are placed on top of the pad, while the motor nerves are beneath the pad, away from the operative field.

After the sensory nerves are exposed, each sensory nerve root is divided into 3-5 rootlets. Each rootlet is tested with electromyography, which records electrical patterns in muscles. Rootlets are ranked from 1 (mild) to 4 (severe) for spasticity. The severely abnormal rootlets are cut. This technique is repeated for rootlets between spinal nerves L2 and S2. Half of the L1 dorsal root fibers are cut without EMG testing.

When testing and corresponding elimination are complete, the dura mater is closed, and fentanyl is given to bathe the sensory nerves directly. The other layers of tissue, muscle, fascia, and subcutaneous tissue are sewn. The skin is typically now closed with glue, but there are sometimes stitches to be removed from the back after 3 weeks. The surgery takes approximately 4 hours and typically involves a team of about one surgeon and one anesthesiologist. The patient then goes to the recovery room for 1–2 hours before being transferred to the intensive care unit overnight. Transfer from the ICU to a recovery room in the hospital is then done to enable direct post-surgical observation by the neurosurgeon and surgical team, but this usually lasts only about 3 days, during which the team performs range-of-motion tests that they record and compare to pre-surgery levels. After that short period, the patient, depending on circumstances and appropriateness, is either transferred to inpatient recovery or is linked to an intense outpatient exercise program and discharged from the hospital.

According to clinicians, it usually takes about one year from the date of surgery to achieve maximum results from SDR. However, videos from St. Louis Children's Hospital website have shown continued marked improvement as much as 5 years post-surgery, and assumedly, if the person keeps exercising intensely, potential for continued improvement and strengthening is, just as in a person born with normal muscle tone and range of motion, unlimited.