Muscular spasm, the etiology of which remains elusive, has been difficult to control. The authors, therefore, proposed selective restraint of forced contractions by a closed-loop circuit. In four dogs, the strap (n = 6) and thyroarytenoid (n = 4) muscles were submitted to tetanic contractions via bipolar supramaximal stimulation (30 Hz, 6 mA, 0.5 msec) of ansa hypoglossi and recurrent laryngeal nerves, respectively. Subsequent reduction of distance between two sonomicrometer crystals embedded into muscle was used in lieu of "spastic information" for a stimulator to deliver blocking signals through tripolar electrodes passed downstream. By modifying frequency (30-110 Hz) and current (60-95%) distribution between the central cathode and the peripheral anodes, significant relaxation (up to 100%) was recorded within "blocking windows," varying with each nerve (3-18 mA sweeps). The selective restraint of unwanted contractions, leaving "normal" subthreshold tone undisturbed, may offer a more mature approach to spastic disorders than destructive procedures, such as nerve section and its chemical counterpart, botulinum toxin injection.
No takes yet. Share an insight, caveat, or question.
Broniatowski et al. (1992) studied this question.