Selective Dorsal Rhizotomy (SDR) is a specialized neurosurgical procedure designed to manage chronic and severe muscle stiffness, known as spasticity. The procedure directly targets the overactive nerve signals that cause muscles to contract involuntarily. The goal is to permanently reduce muscle stiffness in the lower limbs, allowing for improved muscle function by eliminating abnormal reflex activity originating from the spinal cord.
Understanding Patient Selection
Candidacy for Selective Dorsal Rhizotomy depends on a comprehensive evaluation by a specialized, multidisciplinary team. The primary indication is spasticity, typically affecting both legs (spastic diplegia), often a symptom of neurological conditions. A child must demonstrate sufficient underlying muscle strength and motor control to benefit, as the surgery only removes abnormal stiffness, revealing the true underlying muscle capacity.
The ideal age range for the surgery is between three and ten years old, maximizing the potential for post-operative motor learning and rehabilitation. Patients undergo extensive testing, including motor function assessments, orthopedic evaluations, and gait analysis. These tests help determine the severity and distribution of spasticity and the child’s potential for functional improvement.
A child’s ability to participate in and adhere to the rigorous post-operative physical therapy regimen is a significant factor. SDR is not recommended for individuals with severe fixed joint deformities (contractures) or those whose primary difficulty is due to poor balance or involuntary movements (dystonia). The selection process ensures the surgery is performed only on those who possess the best chance of achieving meaningful functional gains.
Detailing the Surgical Procedure
The Selective Dorsal Rhizotomy procedure is performed under general anesthesia, typically beginning with a small incision made over the lower back, providing access to the lumbar spine. The neurosurgeon then exposes the protective covering of the spinal cord to reach the nerve roots that control sensation and movement in the legs. These nerve roots are bundled together as they exit the spinal cord, but they naturally divide into two parts: the ventral (motor) roots and the dorsal (sensory) roots.
The procedure focuses on the sensory nerve roots, which relay signals from the muscles back to the spinal cord. The surgeon separates the sensory nerve roots, known as dorsal rootlets, into smaller bundles. Each rootlet is then tested individually using a fine electrical stimulator while monitoring the corresponding muscle’s electrical response (electromyography or EMG). This monitoring allows the surgical team to distinguish between nerve fibers carrying normal signals and those transmitting the abnormal, overactive signals responsible for spasticity.
The term “selective” refers to the precise action of cutting only a percentage (often 30 to 50 percent) of the abnormal sensory nerve rootlets while preserving the normal ones. Cutting these spastic-signal-carrying fibers breaks the abnormal reflex arc, eliminating excessive muscle stiffness. This technique achieves a permanent reduction in spasticity without negatively affecting normal sensation or intentional muscle movement.
Post-Operative Recovery and Intensive Rehabilitation
Immediately following the procedure, the child typically spends about five days in the hospital for monitoring and initial recovery. The reduction in spasticity is noticeable right away, but this sudden change often reveals underlying muscle weakness previously masked by the stiffness. Pain management and monitoring for cerebrospinal fluid leaks are prioritized during this initial phase.
Intensive physical therapy (PT) begins within days of the surgery and is an inseparable part of the treatment protocol. This structured rehabilitation is necessary to capitalize on the neurosurgical gains and teach the body new, functional movement patterns. The initial focus is on strengthening the newly “unlocked” muscles, which were historically restricted by stiffness.
The rehabilitation period is often lengthy, requiring months to a year or more of dedicated therapy. Physical therapists work on improving core strength, balance reactions, and gait training to establish an efficient, coordinated walking pattern. Without this intensive and sustained rehabilitation, the full functional potential offered by the SDR surgery cannot be realized.
Functional Improvements and Long-Term Outcomes
The most immediate and durable long-term outcome of Selective Dorsal Rhizotomy is the permanent elimination of the targeted spasticity. Since the problematic sensory nerve fibers are physically cut, abnormal muscle stiffness does not return, providing a stable foundation for motor development. This stability helps prevent the progression of secondary orthopedic problems, such as joint deformities and bone misalignment, often caused by chronic spasticity.
Functionally, the combination of permanent spasticity reduction and intensive physical therapy leads to significant improvements in gross motor skills. Patients often experience better balance, increased range of motion, and a more efficient, coordinated gait. The reduction in muscle tightness decreases the energy expenditure required for movement, leading to increased stamina and a reduction in pain associated with muscle spasms. These functional benefits are often sustained many years after the surgery, resulting in measurable improvement in the overall quality of life.