Asunto(s)
Neurocirugia/historia , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Estados UnidosRESUMEN
OBJECTIVE: Considerable overlap exists in nerve root innervation of various muscles. Knowledge of myotomal innervation is essential for the interpretation of neurological examination findings and neurosurgical decision-making. Previous studies relied on cadaveric dissections, animal studies, and cases with anomalous anatomy. This study investigates the myotomal innervation patterns of cervical and lumbar nerve roots through in vivo stimulation during surgeries for spinal decompression. METHODS: Patients undergoing cervical and lumbar surgeries in which nerve roots were exposed in the normal course of surgery were included in the study. Electromyography electrodes were placed in the muscle groups that are generally accepted to be innervated by the roots under study. These locations included levels above and below the spinal levels undergoing decompression. After decompression, a unipolar neural stimulator probe was placed directly on the nerve root sleeve and constant current stimulation in increments of 0.1 mA was performed. Current was raised until at least a 100 µV amplitude-triggered electromyographic response was noted in 1 or more muscles. All muscles that responded were recorded. RESULTS: A total of 2295 nerve root locations in 129 patients (mean age 57 ± 15 years, 47 female [36%]) were stimulated, and 1589 stimulations met quality criteria and were analyzed. Four hundred ninety-five stimulations were performed on roots contributing to the cervical and brachial plexus from C-3 to T-1 (31.2%), and 1094 (68.8%) were roots in the lumbosacral plexus between L-1 and S-2. The authors were able to construct a statistical map of the contributions of each cervical and lumbosacral nerve root for the set of muscle groups monitored in the protocol. In many cases the range of muscles innervated by a specific root was broader than previously described in textbooks. CONCLUSIONS: This is the largest data set of direct intraoperative nerve root stimulations during decompressive surgery, demonstrating the relative contribution of root-level motor input to various muscle groups. Compared with classic neuroanatomy, a significant number of roots innervate a broader range of muscles than expected, which may account for the variability of presentation between patients with identical number and location of compressed roots.
Asunto(s)
Músculo Esquelético/inervación , Raíces Nerviosas Espinales/fisiología , Adulto , Anciano , Estimulación Eléctrica , Electromiografía , Femenino , Humanos , Masculino , Persona de Mediana Edad , Monitoreo Intraoperatorio , Conducción Nerviosa/fisiologíaRESUMEN
PURPOSE: First-division trigeminal neuralgia, or tic douloureux refractory to medications, presents problems to the surgeon because of the desirability of preserving corneal sensation. A new operation is described that may provide longer duration of pain relief than conventional supraorbital neurectomy, with preservation of the corneal reflex. METHODS: Four patients underwent resection of the supratrochlear and supraorbital nerves within the orbit accessed from an upper eyelid skin crease incision. RESULTS: Three patients with typical idiopathic trigeminal neuralgia involving branches of the frontal nerve are without pain 22 to 25 months after surgery. The final patient with atypical pain had no improvement after the procedure. Frontal nerve distribution anesthesia is present in all patients. Postoperative ptosis resolved in all patients within 4 months of surgery. CONCLUSIONS: This procedure should be added to the treatment options for patients with first-division trigeminal neuralgia. By avoiding injury to the trigeminal root and ganglion, this surgery carries no risk of facial motor dysfunction, dysthesia, and/or anesthesia in the other trigeminal branches including corneal anesthesia.