Selective dorsal rhizotomy: A multidisciplinary approach to treating spastic diplegia

Abstract

Background: Spasticity is a motor disorder that interferes with mobility and affects the quality of life. Different approaches have been utilized to address patients with spastic diplegia, among which is selective dorsal rhizotomy (SDR). Although SDR has been shown to be efficacious in treating spastic patients, many neurologists and neurosurgeons are not well aware of the procedure, its indications, and expected outcomes due to the limited number of centers performing this procedure.

Objectives: The aim of this study is to describe the collaborative multidisciplinary approach between neurosurgeons, neurophysiologists, and physiotherapists in performing SDR. In addition, we delineate three illustrative cases in which SDR was performed in our patients.

Materials and methods: A retrospective review and analysis of the clinical records of our three patients who underwent SDR was conducted and reported. Patients' outcomes were evaluated and compared to preoperative measurements based on clinical examination of power, tone (Ashworth scale), gait, and range of motion, as well as subjective functional assessment, gross motor function classification system, and gross motor function measure with follow-up at 6, 12, and 24 months postoperatively. A detailed description of our neurosurgical technique in performing SDR in collaboration with neurophysiology and physiotherapy monitoring is provided.

Results: The three patients who underwent SDR using our multidisciplinary approach improved both functionally and objectively after the procedure. No intraoperative or postoperative complications were encountered. All patients were doing well over a long postoperative follow-up period.

Conclusion: A multidisciplinary approach to treating spastic diplegia with SDR can provide good short-term and long-term outcomes in select patients suffering from spastic diplegia.

Keywords: Cerebral palsy; intraoperative monitoring; neurophysiology; physiotherapy; selective dorsal rhizotomy; spastic diplegia; spasticity.

Figure 1

Sensory electrode placement for somatosensory evoked potential from posterior tibial nerve along with electromyography needle placement for various lower limb muscle roots (a and b). Scalp electrode placement for somatosensory evoked potential recording electrodes along with transcranial motor evoked potentials stimulating electrodes (c). Before collecting neurophysiology data, confirmation of good electrical setup with impedance check (all green) showing <5 kΩ impedance should be established (d)

Figure 2

Free running electromyographies showing root irritation at various cauda equina levels while the surgeon is working on the lower lumbar and sacral roots: anal sphincter irritation (I and II), right hamstring muscles irritation (III), right gastrocnemius muscle irritation (IV), and right extensor hallucis brevis irritation (V), the remaining muscles show no root irritation (a). Identifying root threshold with single pulse technique showing triggered electromyogram responses at 3 mA on the left side (b). Identifying and grading the rootlet with 50-Hz train technique showing sustained discharges on the left side at 3 mA (c). Transcranial motor evoked potentials showing the presence of compound muscle action potentials confirming the integrity of specific motor roots (d)

Figure 3

Operating team setup in photographic (a) and schematic (b) representation: Physiotherapist (PT) is positioned behind the screen and transparent drapes (dotted lines) where she can visualize the surgeons (S) stimulating the rootlets and the surgeons are able to see the lower extremities moving. The anesthetist (An) keeping the patient light enough for stimulation without moving or sensing the stimulations. The neurophysiologist (NP) supervising the neurophysiology technicians (NT) as they stimulate and record results. The team will concordantly interpret the results and make concurrent decisions on what nerve rootlets to rhizotomize. The nurse (Ns) is in the lower left side of the patient

Figure 4

The laminae (L) of L2-S1 are opened, wrapped in gauze and retracted superiorly. Cauda equina (CE) is observed and arachnoid webs are released to identify and separate the ventral from the dorsal roots (a and b). The dorsal sensory root (DR) easily separated from the ventral motor root (VR) using Sabbagh–Bunyan dissecting electrodes (Bl: Blade electrode, Bp: Ball-probe electrode). The roots are uniting as they exit the spinal canal into the dural sleeve through the neural foramen (NF) (c). The dorsal root is divided into five rootlets (R-a, R-b, R-c, R-d and R-e). R-c and R-e (solid arrows) are selected for rhizotomy. Bipolar cautery is performed and micro-scissors (Sc) are used to rhizotomize the selected rootlets. This process is done one level and one side at a time (d)