- Neurotomy
- Dorsal root entry zone rhizotomy (DREZotomy)
- Selective functional dorsal rhizotomy (SFDR)
- Intrathecal Baclofen infusion (ITB therapy)
Neurotomy
Neurotomy involves partial sectioning of one or more of the motor branches of the nerve(s) innervating targeted muscle(s) in which spasticity is present.
It interrupts the segmental reflex arc by acting on both afferent and efferent pathways. Neurotomy eliminates the afferent pathway corresponding to proprioception of the concerned muscle and induces paralysis by section of the efferent pathway.
Neurotomy of the sensory nerve fibres should not be done, as even partial sectioning could result in deafferentation pain.
The surgery is done with the aid of microscope and intraoperative nerve stimulator to identify and selectively disconnect the involved motor nerves.
- Pre-procedure test
Before recommending a selective peripheral neurotomy, a test using motor blocks innervating the targeted muscle(s) is of prime importance, as their effects will mimic the outcome of selective neurotomy on the injected nerve.
Botulinum toxin injections can be used as a ‘‘prolonged’’ test for several weeks or months before pursuing neurosurgical treatment.
Procedure
- The motor branches are isolated from the nerve trunk or dissected and identified, within the fascicles of the nerve trunk, several centimetres proximal to the formation of an identifiable branch.
- Anatomical knowledge is the key in identification of fascicles but needs to be checked by the study of the muscular responses to bipolar electrical stimulation (NIMBUS: Multifunctional Neuro-Stimulator, Hemodia, Toulouse France).
- Stimulation is performed with a 2 Hz frequency, at low intensity – ordinarily 1 mA – to avoid electrical diffusion and an incorrect interpretation.
- The response to stimulation must be visualized in the form of clinically observable movements of the limb muscles and/or EMG recordings.
- Extent of the nerve resection- is done under microscope and it must be limited to sectioning of 50–80% (usually 75%) of all branches to a targeted muscle in order to be effective.
- The resection is 5-mm long from the proximal stump, which is coagulated with a fine bipolar forceps to prevent regrowth of fibres.
- Care must be taken with the sensory fibers, if too many cut in the sensory peripheral nerve it may induce neurogenic pain.
Surgery for the Lower Limb
- Obturator Neurotomy for the Hip
- Hamstring Neurotomy for the Knee
- Tibial Neurotomy for the Foot
- Anterior Tibial Neurotomy for Extensor Hallucis
- Femoral Neurotomy for the Quadriceps
Surgery for the Upper Limb
- Pectoralis Major Neurotomy for the Shoulder
- Teres Major Neurotomy for the Shoulder
- Musculo-cutaneous Neurotomy for the Elbow
- Median Neurotomy for Wrist and Fingers
- Ulnar Neurotomy for Wrist and Fingers