Selective Dorsal Rhizotomy

What is Selective Dorsal Rhizotomy?

Selective Dorsal Rhizotomy is an operation on the back and spinal cord in which the dorsal nerve roots are divided into smaller rootlets.  Each of these rootlets is stimulated to see which cause spasticity.  The abnormal nerve rootlets are selectively cut, while the more normal ones are left in tact. 

What does the surgery involve?

An incision of approximately 15 centimeters is made along the center of the lower back.  A laminotomy is performed which temporarily removes the posterior part of the underlying vertebrae.  Once the spinal cord is exposed, the dorsal sensory nerves of L2 to S2 (the nerves which control the legs) are identified.  Each sensory nerve root is divided into four to seven rootlets.  Each rootlet is tested by an electromyogram (EMG) machine which records the electrical pattern in the corresponding muscle.  This pattern is recorded on a computer and studied by the neurosurgeon and the neurologist.   As well, the muscles are simultaneously being palpated by the physiotherapist to determine contractions.  This technique is repeated three (3) times for each rootlet from L2 to S2.  The rootlets which demonstrate a consistently abnormal response are selectively cut.

Goals of Selective Dorsal Rhizotomy according to patient groups

Children with spastic cerebral palsy are classified into five (5) groups according to their function before surgery.  The goals of treatment for each group are described below:

Group 1 :  Pre-surgery function:  Independent ambulators   Post surgery goals:  Improve appearance and efficiency of walking.

Group 2:  Pre-surgery function:  Ambulators dependent on assistive devices (canes, crutches, walkers)  Post surgery goals:  Improve quality of walking and decrease amount of assistance required for ambulation and transfers. 

Group 3:  Pre-surgery function:  Quadruped crawlers (either reciprocal or non reciprocal; ie. bunny hoppers.  Post surgery goals:    Improve ability to move through developmental sequence; possible with assistive devices, increase independence in self care activities. 

Group 4:  Pre-surgery function:  Totally dependent; no locomotive abilities.  Post surgery goals:  Improve care taking; facilitate positioning in adaptive equipment. 

Who is a  candidate for SDR:

The child with cerebral palsy who would benefit from Selective Dorsal Rhizotomy is:

a)  a child with enough strength whose level of function would improve once the spasticity is eliminated, or

b)  in some cases, a child who is partially or completely dependant for activities of daily living, where eliminating spasticity would improve care taking and positioning.