Selective Dorsal Rhizotomy for Cerebral Palsy
by Warren Marks
Cerebral palsy is a motor disorder caused by a nonprogressive injury to the developing brain. Limited mobility is a common problem for people with cerebral palsy. For children with cerebral palsy, the loss of mobility creates all kinds of health and social issues. As youngsters, the inability to keep up with peers creates the potential for social isolation. The loss of independence can produce a variety of predictable social consequences. Lack of mobility can also result in obesity which further erodes mobility. As adults, there is an increase in diabetes, heart disease and joint problems. With a prevalence of 3 per 1000, Cerebral palsy is the most common disabling movement disorder in children. It is more common among infants born prematurely. This is especially true for diplegic cerebral palsy which primarily involves the legs and is often seen in the context of periventricular encephalomalacia (PVL).
Relying on increased muscle tone for standing and walking actually promotes progressive muscle weakness. Muscle tone is the resting tension on muscles. Spasticity is caused by an upper motor neuron lesion that causes increased muscle tone marked by velocity dependent resistance to muscle stretching. This Increased tone produces unnatural and imbalanced forces on joints and bones creating orthopedic problems. Sensory feedback from the muscle through the dorsal roots of the spinal cord modulates muscle tone. Strength is the ability to produce work. Movement is the work output of muscle strength. Work in walking is the propulsion of the trunk in the desired direction, usually forward. Chronically increased (or decreased) tone impairs the ability to build muscle strength. Motor output to the muscle comes via the ventral roots of the spinal cord.
Treatment for spasticity can include physiotherapy, bracing, medications, and botulinum toxin injections. For severe spasticity, intrathecal baclofen necessitates implanting a battery driven programmable infusion pump. Selective dorsal rhizotomy is a permanent neurosurgical procedure to reduce spasticity.
Selective dorsal rhizotomy – the process
Candidates for SDR are evaluated in our complex motor disorders clinic by the multidisciplinary movement disorder team – an experienced pediatric movement disorders neurologist, physical therapist, orthotist. Additional support is provided by a social worker, nutritionist and a nurse clinician for patient education. Patients undergo gait analysis in the emPower center, our state of the art motion analysis lab, to carefully detail the components of muscle strength, tone and orthopedic bone and joint alignment. Individual patient goals and expectations are then detailed. Once the family and evaluation team are in agreement to proceed, patients are evaluated by Dr. Roberts for evaluation and further explanation of the surgery. A final consultation between neurology and neurosurgery completes the pre-surgical process.
Selective dorsal rhizotomy – the procedure
The spinal cord is exposed and dorsal roots are identified. Each dorsal root is meticulously subdivided into individual rootlets. Each rootlet is then stimulated with a small amount of electrical current and muscle activity is measured. The response dictates whether to cut or preserve an individual nerve rootlet. Typically roots from L1 or L2 through S1 are evaluated. Following the surgery and post-operative recovery, patients come to our inpatient rehabilitation unit (RCU).
Patient selection process:
Who are the best candidates:
The ideal candidate for SDR is an ambulatory or nearly ambulatory patient with diplegic cerebral palsy with good motivation and family support. The best time for SDR is between 4 and 10 years of age. The team will review expectations and establish goals with the family prior neurosurgical referral.
Expect a 4-week hospitalization for the surgery and initial rehabilitation, followed by 3-4 months of intense outpatient therapy.
Your SDR Team:
Neurology and rehabilitation: Warren Marks, MD, Fernando Acosta, MD, Stephanie Acord, MD, Marcie Baldwin, PNP, Erin Davis, PNP
Neurosurgery: Richard Roberts, MD, Grace Crotzer, PA
Physical Therapy: Angela Pomykal, PT
Nurse Clinician: MaryAnn Reed, MSN
Social Worker: Samanta Juric, MSW
Nutrition: Jessica Holy, RD
Motion Analysis: Lindsay Luker, PT, DPT, Mary Pfeffer, MSPT, John Kuruvilla
Patients can be referred to the Cook Children’s Movement Disorders Specialists in our Neurology department at (682) 885-2500.