Implantable FES system for upright mobility and bladder and bowel function for individuals with spinal cord injury.

STUDY DESIGN: Postintervention. OBJECTIVES: To determine the effectiveness of the Praxis multifunctional implantable functional electrical stimulation (FES) system (Neopraxis Pty. Ltd, Lane Cove, NSW, Australia) to provide standing and stepping ability and bladder and bowel management for individuals with motor complete thoracic level spinal cord injuries (SCI). SETTING: Pediatric orthopedic hospital specializing in SCI. SUBJECTS: Three males, ages 17 and 21 years, with motor-complete thoracic level SCI and intact lower motor neurons to the muscles targeted for stimulation. METHODS: Each subject was successfully implanted with the Praxis FES system. All three subjects received electrodes for upright mobility and the first two subjects received additional electrodes for stimulated bladder and bowel management. Following training, subjects were evaluated in their ability to use FES for nine mobility activities. Acute and chronic experiments of the effect of stimulation on bowel and bladder function were also performed. RESULTS: All three subjects could independently stand up from the wheelchair and could walk at least 6 m using a swing through gait pattern. Two subjects were able to independently perform swing through gait for 6 min and one subject was able to independently ascend and descend stairs. Suppression of reflex bladder contractions by neuromodulation (subject 1) and stimulated contractions of the rectum (subject 2) were observed in acute experiments. When stimulation was applied over the course of several weeks, a positive effect on bowel function was measured. Stimulated bladder contractions were not achieved. CONCLUSION: The feasibility of using the Praxis FES system for upright mobility and aiding aspects of bladder and bowel function was demonstrated with three subjects with thoracic level SCI.

An implantable neuroprosthesis for restoring bladder and bowel control to patients with spinal cord injuries: a multicenter trial.

OBJECTIVE: To evaluate the safety and efficacy of an implanted neuroprosthesis for management of the neurogenic bladder and bowel in individuals with spinal cord injury (SCI). DESIGN: Prospective study comparing bladder and bowel control before and at 3, 6, and 12 months after implantation of the neuroprosthesis. SETTING: Six US hospitals specializing in treatment of SCI. PATIENTS: Twenty-three neurologically stable patients with complete suprasacral SCIs. INTERVENTION: Implantation of an externally controlled neuroprosthesis for stimulating the sacral nerves and posterior sacral rhizotomy. MAIN OUTCOME MEASURES: Ability to urinate more than 200mL on demand and a resulting postvoid residual volume of less than 50mL. RESULTS: At 1-year follow-up, 18 of 21 patients could urinate more than 200mL with the neuroprosthesis, and 15 of 21 had postvoid volumes less than 50mL (median, 15mL). Urinary tract infection, catheter use, reflex incontinence, anticholinergic drug use, and autonomic dysreflexia were substantially reduced. At 1-year follow-up, 15 of 17 patients reduced the time spent with bowel management. CONCLUSIONS: Neural stimulation and posterior rhizotomy is a safe and effective method of bladder and bowel management after suprasacral SCI.

Economic consequences of an implanted neuroprosthesis for bladder and bowel management.

OBJECTIVE: To determine whether an implanted neuroprosthesis for bladder and bowel management is less costly than conventional techniques. DESIGN: Retrospective cost-identification analysis with comparison before and after implantation of the neuroprosthesis. SETTING: Life-care planning interviews in patients' homes. PATIENTS: Twelve patients with complete suprasacral spinal cord injuries and neurogenic bladder and bowel. INTERVENTION: Implantation of a neuroprosthesis for electric stimulation of the sacral nerves and posterior sacral rhizotomy. MAIN OUTCOME MEASURES: Annual costs of bladder and bowel care with and without the neuroprosthesis, projected over 10 years. RESULTS: Bladder and bowel care costs were reduced by over 80%, from a median of 8152 dollars a year for conventional care to a median of 948 dollars a year. With the neuroprosthesis, median annual costs for bladder supplies were reduced from 3368 dollars to 58 dollars; for medications, from 1866 dollars to 108 dollars; for medical care, from 656 dollars to 96 dollars; and for bowel care supplies, from 205 dollars to 87 dollars. After 5 years, the cumulative costs of treatment with the neuroprosthesis, including the cost of the device and its implantation and maintenance, equaled those of conventional care. Thereafter, savings from the implanted neuroprosthesis are projected to increase progressively throughout the patient's life. CONCLUSION: A neuroprosthesis implant with posterior rhizotomy greatly reduces the cost of managing the neurogenic bladder and bowel.

Reduction of costs of disability using neuroprostheses.

The lifetime costs associated with spinal cord injury are substantial. Assistive technology that reduces complications, increases independence, or decreases the need for attendant services can provide economic as well as medical or functional benefit. This study describes two approaches for estimating the economic consequences of implanted neuroprostheses utilizing functional electrical stimulation. Life care plan analysis was used to estimate the costs of bladder and bowel care with and without a device restoring bladder and bowel function and to compare these with the costs of implementing the device. For a neuroprosthesis restoring hand grasp, the costs of implementation were compared to the potential savings in attendant care costs that could be achieved by the use of the device. The results indicate that the costs of implementing the bladder and bowel system would be recovered in 5 years, primarily from reduced costs of supplies, medications, and procedures. The costs of the hand grasp neuroprosthesis would be recovered over the lifetime of the user if attendant time was reduced only 2 hours per day and in a shorter time if attendant care was further reduced. Neither analysis includes valuation of the quality of life, which is further enhanced by the neuroprostheses through restoration of greater independence and dignity. Our results demonstrate that implantable neuroprosthetic systems provide good health care value in addition to improved independence for the disabled individual.

Health promotion in motion: improving quality of life for persons with neurogenic bladder and bowel using assistive technology.

The neurogenic bladder and bowel lead to many complications in individuals with spinal cord injury (SCI). Management of these neurological complications is a multidimensional challenge for persons with SCI and their caregivers, and can affect the person medically, economically, socially, and personally. This may result in social isolation, poor self-image, and overall decreased quality of life (QOL). When facing this challenge, nurses working with persons with SCI must expand their practice to include more than traditional preventive care. A newly available technique for promoting health with a neurogenic bladder and bowel is the VOCARE Bladder and Bowel Control System. Sixteen persons with SCI who received this system were interviewed by telephone and asked for their recollections of health and QOL pre-operatively in relation to bladder and bowel care and to rate changes in their QOL post-implant. Post-operatively, the recipients reported improved health, a decrease in costs of management of their neurogenic bladder and bowel, increased independence leading to less social isolation, increased sense of control, increased feelings of self-worth, and overall improvement in QOL. These outcomes illustrate the global impact that can be made on the lives of persons with SCI by health services that go beyond prevention of complications and into the realm of health promotion.

Functional conditions of micturition induced by selective sacral anterior root stimulation: experimental results in a canine animal model.

Electrical stimulation of the sacral anterior roots using conventional rectangular current pulses results in a simultaneous contraction of the urinary bladder and the striated urethral sphincter. Using a tripolar nerve cuff electrode with quasitrapezoidal current pulses and appropriate stimulation parameters, hyperpolarization of the nerve-fiber cell membrane under the anode of the stimulating electrode can reversibly arrest action potential propagation in large myelinated nerve fibers, innervating the striated urethral sphincter, while leaving action potential propagation unaffected in small nonmyelinated nerve fibers innervating the urinary bladder smooth muscle (anodal arrest). Using this technique in 19 female mongrel dogs, we studied the effect of bladder filling, level of anesthesia, and sacral deafferentation on bladder pressure, urethral pressure, and urinary flow. Effective micturition could be induced only after complete dorsal rhizotomy, abolishing reflex contraction of the striated urethral sphincter, when blocking quasitrapezoidal current pulses were used for stimulation. Stimulation with rectangular current pulses directly induced a rise in distal urethral pressure, preventing micturition during stimulation.

Review of sacral electrical stimulation in the management of the neurogenic bladder.

In patients with spinal cord injury above the conus medullaris, electrical stimulation of the sacral anterior nerve roots can produce micturition with low residual volumes of urine and reduced urinary tract infection. Vowing pressures appear to be maintained at safe levels by the use of an intermittent pattern of stimulation. The procedure is usually combined with division of the sacral posterior roots, which increases bladder capacity and continence; this also increases bladder compliance, which may be protective for the upper urinary tracts.The procedure has now been applied in about 900 patients with spinal cord injury, some of whom have been followed up for over 15 years. The nerves do not appear to be damaged by long-term stimulation and technical faults with the equipment are now uncommon.

Electrical stimulation of sacral roots for micturition after spinal cord injury.

In patients with suprasacral spinal cord injury, electrical stimulation of the sacral anterior nerve roots can produce micturition with low residual volumes of urine and reduced urinary tract infection. Voiding pressures can be maintained at acceptable levels by selective peripheral neurotomy and myotomy or, more commonly, by an intermittent pattern of stimulation. Occasionally, external sphincterotomy is required. The procedure is usually combined with division of the sacral posterior roots, which increases bladder capacity and continence; this also increases bladder compliance, which may be protective for the upper urinary tracts. A reduction in constipation usually is observed, and some patients are able to defecate with the aid of electrical stimulation. Penile erection is produced in a substantial proportion of male patients. The procedure has now been applied in about 700 patients with spinal cord injury, some of whom have been followed for nearly 15 years. The nerves do not appear to be damaged by long-term stimulation, and technical faults with the equipment are now uncommon.

Management of the neurogenic bowel in patients with spinal cord injury.

Bowel dysfunction in patients with spinal cord injury has a significant impact on quality of life as well as causing morbidity and death. This article reviews the pathophysiologic features of the neurogenic bowel of patients with spinal cord injury. Also discussed are the clinical manifestations, current options for management, and newer approaches that address this chronic and debilitating problem.

Neural prostheses: clinical applications of functional electrical stimulation in spinal cord injury.

Function lost in spinal cord injury can be partially restored in some patients by electrical stimulation of remaining neurons. Neural prostheses designed for this purpose have been under development for several decades and are now in increasing clinical use. Applications are outlined for restoration of respiration, bladder, bowel and sexual function, exercise, hand grasp and standing and walking.

Constipation associated with chronic spinal cord injury: the effect of pelvic parasympathetic stimulation by the Brindley stimulator.

Ten subjects with severe constipation due to complete spinal cord injury (SCI) had prolonged oro-anal transit time (p less than 0.01), diminished faecal water content (p less than 0.05) and a reduced frequency of defaecation (p less than 0.01) compared to 10 non-SCI subjects. Paraplegics with an implanted Brindley S234 anterior sacral nerve root stimulator had a significant increase in frequency of defaecation (p less than 0.01), compared to the SCI group while the faecal water content was less although not significantly so. The Brindley stimulator group also showed a more rapid colonic transit than the SCI group but this did not reach statistical significance. SCI is associated with constipation which therefore appears to be favourably influenced by the Brindley S234 anterior nerve root stimulator. The effects produced are compatible with stimulation of left colonic motility, which facilitates the emptying of the distal colon, but also suggest that part of the response restricts transit in some areas of the colon or rectum. Since the motility changes induced by the Brindley stimulator do not affect the right colon a relatively greater residence time of the faecal bolus in this part of the large bowel would enhance water absorption.

The effects of neuromuscular stimulation on muscle tone at the knee in paraplegia.

Resting muscle tone of the leg was measured in terms of thigh muscle stiffness and knee resonant frequency in muscles of spinal cord injured subjects who had been involved in an electrical neuromuscular stimulation training programme of the thigh muscles over at least 2 months. The thigh circumference of these patients was 6.6% larger than before training commenced (P less than 0.001) and showed increased muscle stiffness and resonant frequency compared to a similar group of paralysed subjects who had not used any neuromuscular stimulation. Resonant frequency and stiffness after the long-term training were similar to those of non-injured controls and therefore the stimulation programme seemed to reverse the effects of paralysis on muscle tone. Short periods of rest (30 min) caused increased muscle stiffness in non-injured controls and paralysed muscles trained by neuromuscular stimulation. Additional 15 min periods of neuromuscular stimulation further increased muscle stiffness in the trained muscles but also in the muscles of paralysed subjects who had no long-term neuromuscular training. In contrast, 15 min sessions of passive movement of the knee decreased muscle stiffness in long-term trained paralysed muscles and untrained paralysed muscles. Knee resonant frequency was also significantly decreased in the trained paralysed muscles. Results show that muscle tone varies depending on the amount of previous movement or rest and that although neuromuscular stimulation of paralysed muscles increases muscle stiffness and knee resonant frequency, it is in fact restoring such properties of the muscle to a state approaching that of non-injured controls.

Sperm retrieval by electro-ejaculation. Preliminary experience in patients with secondary anejaculation.

Twelve patients with spinal cord injury and 2 diabetics with secondary anejaculation underwent 26 sessions of electro-ejaculation, using a technique which has previously been popular only in veterinary medicine. Ejaculate was obtained on 21 occasions. Semen quality was adequate for cryostorage on 9 occasions (8 patients); on 8 occasions (5 patients) it was used for immediate artificial insemination of the partner. To date, there has been 1 pregnancy resulting in a live birth.

The action of cisapride on the chronic constipation of paraplegia.

Paraplegic patients have intractable constipation associated with prolonged colonic transit time. The agent Cisapride significantly reduced the colonic transit time from 7.7 days to 5.1 days. It also improved the intraluminal tone in the rectum, resulting in a significant reduction in maximal rectal capacity from 305.8 ml to 224.3 ml. There was a reduction in residual urine volume from 51.5 ml to 27.7 ml. The increased number of stools containing transit markers showed that intraluminal mixing was increased by cisapride. Faecal water remained unchanged. A side effect was retention of urine in one subject after sudden withdrawal of the drug but this was avoided by its gradual reduction over 2 days.

Differential effects of sacral anterior root stimulation on anal sphincter and colorectal motility in spinally injured man.

The motility responses of the sigmoid colon, rectum and external anal sphincter to sequential electrical stimulation of the anterior sacral roots (S2, S3 and S4) were studied in five patients with traumatic spinal cord injury. Identical and reproducible results were obtained. S2 stimulation provoked isolated low-pressure colorectal contractions. S3 stimulation initiated high-pressure colorectal motor activity which appeared peristaltic and was enhanced with repetitive stimuli. This response appeared to be frequency-dependent. S4 stimulation increased colonic and rectal tone. External sphincter activity was stimulated in increasing order from S2 to S4. These observations directly elucidate the central control of colorectal motility and may have implications in the treatment of severe constipation following spinal injury.

Wound healing after laser surgery: an experimental study.

Healing after carbon dioxide laser incisions has been assessed in three animal experiments. Nine incisions in pig skin were found to be significantly weaker after 7 days than similar incisions made with a scalpel, but stronger than those made with a cutting diathermy. Laser excision of skin discs in pigs provided a satisfactory base to take split-skin grafts, but graft take around the edges was less complete than after scalpel excisions. Division and anasto mosis of the colon of 75 rats showed that the laser produced anastomoses that were as strong after 7 days as those produced by scalpel or diathermy division, but the laser did not produce the narrowing of the lumen that occurred with diathermy. It is concluded that if epithelial surfaces are particularly thick and slow to cut with the laser than thermal damage will impair healing, but that in general epithelial surfaces need not be avoided in laser surgery.

A micromethod for the activation of human blood lymphocytes in vitro.

A micro culture system is described in which 2.5 X 10(4) human blood lymphocytes in aliquots of 100 mul are stimulated by PHA, Pokeweed, "Varidase" antigen, allogeneic small lymphocytes or mitomycin-C-treated allogeneic LCL cells. Careful regulation of the pH by a combination of bicarbonate and MOPS buffers seems to be important for detecting a response to weak stimuli. High and reproducible levels of activation by powerful stimuli (PHA and LCL cells) can be recorded from even smaller cultures (10(4) responding cells in 40 mul aliquots). The technique allows large numbers of replicate cultures to be set up from a single blood sample so that the time course and/or dose-response relationships can be examined for a range of differen mitogens.