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.
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.
Authors: Hanneke I Berends; Henricus L Journée; Ilona Rácz; Jan van Loon; Roger Härtl; Maarten Spruit Journal: Eur Spine J Date: 2015-08-27 Impact factor: 3.134
Authors: Andreas Rowald; Salif Komi; Robin Demesmaeker; Edeny Baaklini; Sergio Daniel Hernandez-Charpak; Edoardo Paoles; Hazael Montanaro; Antonino Cassara; Fabio Becce; Bryn Lloyd; Taylor Newton; Jimmy Ravier; Nawal Kinany; Marina D'Ercole; Aurélie Paley; Nicolas Hankov; Camille Varescon; Laura McCracken; Molywan Vat; Miroslav Caban; Anne Watrin; Charlotte Jacquet; Léa Bole-Feysot; Cathal Harte; Henri Lorach; Andrea Galvez; Manon Tschopp; Natacha Herrmann; Moïra Wacker; Lionel Geernaert; Isabelle Fodor; Valentin Radevich; Katrien Van Den Keybus; Grégoire Eberle; Etienne Pralong; Maxime Roulet; Jean-Baptiste Ledoux; Eleonora Fornari; Stefano Mandija; Loan Mattera; Roberto Martuzzi; Bruno Nazarian; Stefan Benkler; Simone Callegari; Nathan Greiner; Benjamin Fuhrer; Martijn Froeling; Nik Buse; Tim Denison; Rik Buschman; Christian Wende; Damien Ganty; Jurriaan Bakker; Vincent Delattre; Hendrik Lambert; Karen Minassian; Cornelis A T van den Berg; Anne Kavounoudias; Silvestro Micera; Dimitri Van De Ville; Quentin Barraud; Erkan Kurt; Niels Kuster; Esra Neufeld; Marco Capogrosso; Leonie Asboth; Fabien B Wagner; Jocelyne Bloch; Grégoire Courtine Journal: Nat Med Date: 2022-02-07 Impact factor: 87.241