Selective Dorsal Rhizotomy’ (SDR)
SDR is a permanent procedure that addresses the spasticity at its neuromuscular root: i.e., in the central nervous system that contains the misfiring nerves that cause the spasticity of those certain muscles in the first place. After a rhizotomy, assuming no complications, a child’s spasticity will be completely eliminated, revealing the “real” strength (or lack thereof) of the muscles underneath.
Because the muscles may have been depending on the spasticity to function, there is almost always extreme weakness after a rhizotomy, and a child will have to work very hard to strengthen the weak muscles with intensive physical therapy, and to learn habits of movement and daily tasks in a body without the spasticity.
SDR begins with a 1- to 2-inch incision along the centre of the lower back just above the waist. Ultrasound and an x-ray locate the tip of the spinal cord, where there is a natural separation between sensory and motor nerves. 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. When testing and cutting are complete, the skin is closed with glue. There are no stitches to be removed from the back. Surgery takes approximately 4 hours. The patient goes to the recovery room for 1-2 hours before being transferred to the intensive care unit overnight.
There is always abnormal sensitivity and tingling of the skin on the feet and legs after SDR because of the nature of the nerves that have been worked on, but this usually resolves within 6 weeks. There is no way to prevent the abnormal sensitivity in the feet. Transient change in bladder control may occur, but this also resolves within a few weeks.
In general, there is a combined 5-10% risk of any of the following more serious risks happening as a result of SDR.
• Permanent paralysis of the legs and bladder
• Permanent impotence
• Sensory loss and/or numbness.
• Wound infection and meningitis – usually controlled with antibiotics
• Leakage of the spinal fluid through the wound.
Most rehabilitation from SDR is done on an outpatient basis. Typical base re-strengthening and restoration of full ambulatory function takes about twelve weeks of intensive physical therapy 4-5 times per week, but additional build up and maintenance may require continued 4-5 times per week therapy as much as 6 months post-operatively and with decreasing frequency, for a total of about a year and four months after surgery.
In children who are 2-7 years old and walk with a walker or crutches before SDR, independent walking after the procedure is possible. Once they have achieved independent walking, they can maintain it.
Centres in the UK offering SDR:
Leeds General Infirmary
Alder Hey Children’s NHS Foundation Trust, Liverpool
Nottingham University Hospitals NHS Trust
The Robert Jones and Agnes Hunt Orthopaedic and District Hospital NHS Trust
Centre in the USA offering SDR:
St Louis Children’s Hospital
Further information on SDR
NICE Guidelines on Treatment of Spasticity in Cerebral Palsy by Selective Dorsal Rhizotomy. http://guidance.nice.org.uk/IPG373