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Biomedical subjects

M Broniatowski

Publications and source records attributed to M Broniatowski.

At least 37 records · Page 2Linked to original sources
PubMed1990

Electronic control of laryngeal spasm. I. Blockage of orthodromically induced action potentials in intact canine recurrent laryngeal nerves.

Spastic dysphonia is a central nervous system phenomenon of unknown etiology characterized by uncoordinated voice tremor with erratic patterns of laryngeal contraction. Standard treatments have not been entirely satisfactory. The authors propose to apply a concept of selective nerve activity blockage, which leaves normal contractions undisturbed, as the basis for suppression of laryngeal spasticity. Single pulses of constant duration and increasing amplitude were injected into specially designed blocking electrodes placed around six recurrent laryngeal nerves (three dogs). Vocal cord adduction was reduced or arrested within given "windows" of stimulation levels of the blocking electrodes, while it increased with higher amplitudes when the current was injected via standard bipolar electrodes (controls). Although this study demonstrates the feasibility of blocking action potentials passing along recurrent laryngeal nerves, it might eventually allow control of laryngeal spasm from information taken directly from the affected musculature.

Action Potentials↗
PubMed1990

Artificial restoration of voice. I: Experiments in phonatory control of the reinnervated canine larynx.

Coordinated electronic pacing of implanted nerve pedicles into paralyzed laryngeal muscles has allowed selective dynamic control of abduction, adduction, and elongation of the vocal cords. Modifications of the original circuit in a cervical muscle model has added fine tuning to basic "all-or-none" pacing. Rehabilitation of phonation illustrated the sophisticated nature of voice and the need for restoration of fine tuning. Five mongrel dogs received nerve-muscle pedicles into the thyroarytenoideus, cricothyroideus, and posterior cricothyroideus after denervation of one hemilarynx. Following appropriate reinnervation time, pedicles and intact recurrent laryngeal nerves were injected with currents of variable amplitudes and pulse widths to achieve graded vocal fold control while air was blown intratracheally towards the glottic chink. Videoscopic and spectral analyses indicated that artificial phonation could be restored to frequencies measured in the normal state. These experiments suggested that rehabilitation of the impaired voice by servocontrol might eventually be feasible.

Animals↗
PubMed1990

The deep temporal nerve-orbicularis oculi muscle pedicle as a possible means for reanimation of the upper face.

Selective reinnervation of paralyzed facial musculature using the ansa hypoglossi nerve-muscle pedicle has been shown to be feasible in laboratory animals and in people. Because this structure cannot be brought beyond the level of the orbicularis oris muscle, the deep temporal nerve-orbicularis oculi nerve-muscle pedicle was investigated in six human cadavers as a possible source for reanimation of the paralyzed upper face. These studies show that it is possible to create a nerve-muscle pedicle that can easily reach the orbicularis oculi muscle in all specimens. Interest in electrical control of paralyzed structures to reestablish facial expression may allow further application of our findings.

Facial Muscles↗
PubMed1989

Direct nerve implantation vs. nerve-muscle pedicle: a comparative study of reinnervation in the rabbit.

To determine the optimal method for reinnervation of the paralyzed head and neck musculature, we compared direct muscular nerve implants (DNI) with nerve-muscle pedicles (NMP) in rabbits. In 25 anesthetized animals, one ansa hypoglossi nerve was cut. Five animals served as controls and two groups of 10 each received cross-over DNIs or NMP from one sternothyroid to the contralateral sternohyoid muscle. The transplanted nerves of animals that survived long enough for neurotization to occur (8 DNIs, 5 NMPs) were stimulated with 3 to 10 mA. 0.05 msec pulse trains to obtain force curves from corresponding straps. Fiber diameters and areas were calculated on muscles harvested before the animals were killed. There was a nonsignificant trend toward stronger contraction in the NMP group, but NMP fibers were significantly larger than those in DNI and control groups (p less than 0.001).

Animals↗
PubMed1989

Excitation thresholds for nerve pedicles: a preliminary report.

Ongoing interest in the rehabilitation of paralyzed musculature in the head and neck has focused on the electronic stimulation of nerve-muscle pedicles that have been reimplanted into the incapacitated effector(s). Despite visual and histochemical evidence of reinnervation, it is still not known whether the excitability of a nerve-muscle pedicle (or for that matter a direct nerve implant) is equivalent to or better than that of reinnervated or normal muscle. Such information is necessary for the eventual construction of an implantable stimulator. Eighteen rabbits were anesthetized with intramuscular xylazine and ketamine and the ansa hypoglossi nerve was cut on one side. A crossover nerve-muscle pedicle was brought in from the opposite sternothyroid muscle to the sternohyoid in nine animals; the other nine received a direct nerve implant. After a minimum neurotization period of 3 months and reexploration, an electrical stimulator capable of delivering square wave pulses of variable amplitude and width was used to determine the thresholds of contraction of the nerve pedicles, an intact motor nerve of similar size, a normal muscle, and the reinnervated strap in 16 evaluable rabbits. Strength duration curves were established. The data indicate that thresholds for nerve pedicles are equivalent to those of normal nerves and are significantly lower than those of muscle.

Animals↗
PubMed1989

Dynamic rehabilitation of the paralyzed face--II. Electronic control of the reinnervated facial musculature from the contralateral side in the rabbit.

This work is the continuation of a previous pilot study in the rabbit in which motion originating on the face was picked up by miniature strain gages and channeled synchronously to strap muscles reinnervated via crossover nerve-muscle pedicles. In the current series of experiments, we modified the distal limb of the system to reinnervate the previously paralyzed opposite side of the face via an ansa hypoglossi nerve--thyrohyoid muscle pedicle in five animals. Muscular contraction was induced on the intact side by stimulating different branches of the facial nerve, and corresponding information was channeled to the reinnervated side through an upgraded electronic stimulator via monopolar electrodes placed around the nerve pedicle in the neck. In addition to demonstrating perfect synchrony between intact and reinnervated sides, this facial stimulator allowed the reinnervated side of the face to follow the intact side in a graded and sustained fashion, thus demonstrating that fine tuning of reinnervated facial musculature was possible.

Animals↗
PubMed1989

An artificial myotatic reflex: a potential avenue to fine motor control.

When a striated muscle becomes paralyzed, not only its motor function, but its sensory innervation may be impaired. Methods of rehabilitation have previously focused only on motor innervation, although striated muscles are submitted to self-regulation of length and tension. Indeed, reinnervated muscle may not contract appropriately unless sensory information is available, nor is it known whether sensory receptors are included in the reinnervation process. We hypothesized that the myotatic reflex (MR) would be absent in the event these sensory organs are not reinnervated, and that an artificial myotatic reflex (AMR) would be useful in reestablishing fine motor control. The strap muscles were exposed in six anesthetized rabbits. The MR was verified by stretching an intact sternohyoid muscle. Next, loss of the reflex was documented after the ipsilateral ansa hypoglossi was divided, and a crossover nerve-muscle pedicle (NMP) was brought in from the opposite sternothyroid. After 3 months, the MR was still absent; however, stretch of the contralateral sternohyoid produced a reflex response on the reinnervated side. A strain gauge sutured to the reinnervated muscle was linked to an electronic modulator so that stretch induced electric stimulation of the NMP and contraction (the AMR). We conclude that (1) proprioception is not reestablished in the reinnervated muscle; (2) by contrast, sensory information from the muscle of origin of the NMP is conveyed to the reinnervated side; and (3) the AMR offers promise toward more sophisticated control of paralyzed (i.e., facial, laryngeal) musculature.

Animals↗
PubMed1989

Artificial agonist/antagonist coupling in paralyzed muscles: electronic balance of reinnervated straps from facial activity in the rabbit.

Normal striated muscular contraction such as occurs in the face is the result of finely balanced activities monitored by the central nervous system. Previous approaches to rehabilitation have been limited to restoring only motor function, ignoring the proprioceptive input that normally originates at the level of each muscle. In this pilot study, proprioceptive information originating in facial muscles (considered as agonists) is artificially channeled to nerve pedicles, reinnervating straps in the rabbit to produce antagonist action. Further development of this concept can lead to finer control of reinnervated muscles of the face or elsewhere.

Animals↗
PubMed1988

Artificial reflex arc: a potential solution for chronic aspiration. II. A canine study based on a laryngeal prosthesis.

Long-term and repeated aspiration can result in pneumonia and eventually death. To avoid current techniques which divert or close off the incompetent larynx, the authors have recently described an artificial reflex arc (ARA), in hopes of providing a dynamic solution to this problem. With this concept, a segment of skin surface with intact sensory innervation is implanted into the pharynx in the path of the food bolus. Resulting neural impulses would be detected by a perineural electrode and then channeled to both recurrent laryngeal nerves via an electronic pacemaker to cause vocal fold adduction at the critical time during swallowing. A pilot study using a tubed cervical cutaneous surface has yielded promising results in the canine. In this current study, an alternate means for information pickup based upon use of a miniature strain gage is presented. Mechanical stimulation of the hypopharynx using this "sensory" detector resulted in synchronous laryngeal adduction of the vocal folds, as documented graphically and on videotape.

Animals↗
PubMed1988

Bionic larynx: electronic control of the reimplanted organ in the dog.

Complete rehabilitation of paralyzed head and neck structures has been difficult, and attempts at reinnervation of striated muscles have not consistently succeeded. Recent studies have shown that disabled muscles can be electronically "paced." This, together with recent developments in microelectronics, has led to the concept of the Bionic Larynx. The current experiments involve transposed nerve-muscle pedicles used to selectively reinnervate larynges which were denervated, entirely detached from the animal except for their vascular supply, and then reimplanted. These pedicles were later stimulated using a potentially implantable "pacing unit." It was possible to selectively control the critical functions of the larynx, using as stimuli physiological events that are preserved even when the vocal folds are paralyzed or uncoordinated. Although laryngeal transplantation in humans remains theoretical, these studies show that it could be feasible in the future.

Animals↗
PubMed1987

Dynamic rehabilitation of the paralyzed face: I. Electronic control of reinnervated muscles from intact facial musculature in the rabbit.

An entirely satisfactory solution to dynamic rehabilitation of the paralyzed facial musculature has not yet been found. Recent interest in selective reinnervation of the laryngeal musculature, synchronous with appropriate afferent information, has led us to propose that miniature strain gauges be placed on one or more muscles of facial expression on the intact side to channel electrical signals to the opposite corresponding facial musculature reinnervated via nerve-muscle pedicles. In order to avoid introducing extraneous factors related to facial motion, this principle was first studied on crossover ansa hypoglossi nerve-muscle pedicles in New Zealand white rabbits. Surgery was performed on a total of five animals that were under general anesthesia with xylazine and ketamine, through a midline neck incision. The animals were reexplored after 12 weeks, and after verification that reinnervation had taken place, a vertical incision was made under the external canthus, in order to expose the facial nerve. A miniature strain gauge was then sutured on the facial musculature and connected to a central modulating unit that was, in turn, linked to the nerve-muscle pedicle via a monopolar electrode. Facial wiggle that resulted from direct electrical facial nerve stimulation caused synchronous contraction of all reinnervated strap muscles under study; this was documented on film and through facial and strap muscle activity tracings. Our next step will be to extend this principle to paralyzed facial muscles. If successful, this system could be miniaturized for long-term implantation in human beings.

Animals↗
PubMed1987

Artificial reflex arc: a potential solution for chronic aspiration. I. Neck skin stimulation triggering strap muscle contraction in the canine.

Aspiration can occur when the reflex of deglutition occurring in the brain stem is impaired. Surgical procedures involving the airway have so far failed to provide a long-term solution to this problem. Because the sphincteric properties of the larynx could be used to help separate the air from the food passages on a dynamic basis, we present the concept of an artificial reflex are (ARA) in the canine. The afferent limb of this system consists in a cervical cutaneous sensory surface containing the specific biologic sensors for pressure and stretch, subtended by a corresponding sensory nerve, destined to be eventually implanted into the pharynx. The efferent limb picks up the information resulting from the sensor's distention via a frequency modulator and an amplifier, prior to transmitting it to the recurrent laryngeal nerves through monopolar electrodes, resulting in synchronous glottic closure. In order to test this new concept as a pilot study, this principle was applied in three dogs by using an island of cervical skin tubed on itself and the contralateral strap muscles as effector. Inflation of a Foley catheter introduced into the lumen of this tube resulted in synchronous strap muscle contraction, following corresponding increase in the firing frequency in the subtended sensory nerve. The data obtained in this series of experiments should permit further application at the laryngeal level.

Animals↗
PubMed1986

Penetrating injuries of the neck. Emergency evaluation and management.

The physician who is called upon to attend to a penetrating wound to the neck must set priorities in management. (1) Establish a safe airway. (2) Maintain adequate cardiocerebral perfusion. (3) Assess and identify the type and severity of the wound so that proper decisions can be made about further evaluation and/or transfer for immediate surgical intervention. All this can be accomplished in an orderly fashion by applying the principles for selective surgical exploration of neck wounds outlined in this article. A well-reasoned approach can help avoid unnecessary surgery and yields a high likelihood of recovery.

Emergencies↗
PubMed1986

Laryngeal pacemaker. Part I. Electronic pacing of reinnervated strap muscles in the dog.

The best approach to management of bilateral vocal cord paralysis, with its resultant airway compromise, has not yet been universally agreed upon. Recently proposed methods have included direct stimulation of the laryngeal dilators by the modulation of rhythmic information from the chest wall, diaphragm, phrenic nerve, or accessory muscles of respiration. In such an approach, the information obtained is not necessarily related to inspiration only, and direct implantation of a stimulating electrode into the laryngeal musculature may not be fully efficient and tolerated over time. To obviate such difficulties, the authors propose to broaden the concept of electrical pacing by (1) developing a better source for the triggering of electrical activity during inspiration and (2) devising a reliable means of long-term physiologic stimulation of denervated striated muscle not subject to deterioration over time. Such an experimental unit was constructed in the canine. It is based on afferent information that originates from the mechanical lengthening of the trachea during inspiration and is detected through a linear strain gauge sutured to the tracheal rings. The signal obtained is modulated through an impedance detector and is amplified. An efferent limb consisting of a monopolar cuffed electrode placed around a crossover nerve-muscle pedicle from one sternohyoid muscle to the other was used successfully. Such a preliminary experiment with a strap muscle avoids the extraneous factors related to function of the paralyzed larynx. Successful nerve-muscle pedicle pacing, synchronous with respiration, was verified through electromyographic recordings and direct observation in all animals studied.

Animals↗
PubMed1986

Combined rotary door flap and epiglottic laryngoplasty for reconstruction of large laryngotracheal defects in dogs.

Reconstruction of large laryngotracheal defects may require simultaneous application of more than one surgical technique. This paper reports the advantages gained by combining epiglottic laryngoplasty with the myocutaneous sternohyoid muscle rotary door flap. The two procedures complement each other in achieving structural and functional rehabilitation of extensive defects in the larynx and trachea. Avoidance of intraluminal stents and use of a tracheostomy procedure that does not require an indwelling cannula have yielded improved results.

Animals↗