The first 500 patients with sacral anterior root stimulator implants: general description.

The first 500 patients to have sacral anterior root stimulators implanted for bladder control are described. Of 479 survivors, 424 were using their stimulators when last followed up between 3 months and 16.1 years (mean 4 years) after implantation.

Implant provision of key, pinch and power grips in a C6 tetraplegic.

An 11-channel multiplexed stimulator of nerves and muscles in the left forearm was implanted for hand control in January 1986 in a 21 year old woman who, after sustaining a C6 spinal lesion 7 years earlier, had voluntary shoulder and elbow movement but paralysed hands, trunk and legs. The patient controls the stimulation via a microcomputer control box and an RF transdermal link. We have investigated the control of her stimulated hand with a joystick under her contralateral hand which she moves from the shoulder and elbow. Since 1986, we have tried a variety of joystick control schemes involving power and key grips. Currently, for grip adjustment, forward and backward joystick movements correspond to thumb extension and abduction, respectively giving in addition both finger and wrist extension, whereas right and left joystick movements yield fist closure and thumb opposition/adduction and flexion, respectively. Useful grasps are available by moving the joystick forward and then left (key grip), by moving the joystick backward and left (pinch grip), or by moving the joystick back and right (power grip). Thus, three distinct grips may be selected using these three quadrants of joystick movement. An additional control mode was found to be desirable to augment the patient's limited voluntary wrist positioning and provide wrist stability while adjusting finger grip.

Bladder pressure sensors in an animal model.

Urinary incontinence due to detrusor hyperreflexia might be inhibited on demand if changes in bladder pressure could be detected by sensors and transferred into pudendal nerve electrostimulation. The aim of this study is to investigate how the bladder wall reacts on different sensor implants. Sensors were implanted in twelve goats. In group 1 (n = 8) real sensors were placed on the peritoneal surface of the bladder dome, between the peritoneum and the muscular layer, and between the cervix and bladder. In group 2 (n = 4), dummy sensors were placed between the mucosal and muscular layers. During follow-up as long as 25 months, urodynamic studies, radiographic control and urine cultures were done. In group 1, sensors placed between the peritoneum and muscular layer gave the best results. In group 2, 11 of the 12 sensors eroded. The authors conclude that implantation of sensors in the bladder wall is feasible.

Endoscopically guided bladder neck suspension for continence in paraplegic women with implant driven micturition.

Two paraplegic women who had undergone implantation of a sacral anterior nerve root stimulator to treat their voiding difficulties and recurrent urinary tract infections subsequently suffered from stress incontinence. After urodynamic evaluation they were treated with a Stamey operation which rendered them dry without hindering their implant driven micturition.

A case of ocular tilt reaction and torsional nystagmus due to direct stimulation of the midbrain in man.

A case is presented of a patient who underwent insertion of a periaqueductal grey electrode for the relief of chronic pain. Shortly after insertion, the patient developed a left-sided ocular tilt reaction (OTR). The electrode tip, initially to the right of the midline, was then withdrawn slightly so that it was now on the left side. Stimulation at this point gave rise to a worsening of the tilt reaction, in addition to bilateral counter-clockwise torsional nystagmus. Computerized tomography and stereotactic coordinates indicated that the tip of the electrode was finally situated in the region of the left interstitial nucleus of Cajal (INC). The production of an OTR by stimulation in this region is similar to the phenomenon previously reported in monkeys and cats. The side of the OTR is consistent with previous evidence, suggesting that the utricular pathways cross between medulla and midbrain.

Long-term follow-up of patients with sacral anterior root stimulator implants.

The first 50 patients to receive a sacral anterior root stimulator for bladder control were reviewed by questionnaire in mid-1989. At that time, the follow-up period varied from 5 to 11 years, and 48 of the group were alive; 2 had died from unrelated causes. Forty-one used their implants regularly for micturition and of these, 37 were always or usually continent. Twenty-nine reported no symptomatic urinary infections in the previous year, and only 4 had 3 infections or more. Twenty-seven used their implant to assist defaecation, and 13 of 32 male users reported full implant-driven erections. Side effects are minor, except for stimulus evoked pain sensation, which prevents use of the implant in 3 of the 7 non-users. Two of the other non-users were awaiting repair of their implant faults.

Extradural implantation of sacral anterior root stimulators.

A technique for extradural deafferentation of the S2 to S5 segments and extradural implantation of stimulating electrodes is described, and its application to twelve patients with spinal cord lesions is reported. Nine patients use their implants for micturition, and seven are fully continent. The advantages and disadvantages of this technique compared with the more usual intrathecal procedure are discussed.

Treatment of urinary and faecal incontinence by surgically implanted devices.

Three kinds of implant to treat incontinence are considered. The sacral anterior root stimulator (with sacral posterior rhizotomy) is already effective in urinary incontinence due to spinal cord injury, and will have wider application. The conditional pudendal nerve stimulator and the conditional gracilis nerve stimulator are, respectively, almost untried and entirely untried devices; but they show promise, and if successful may help very many patients.

Hypogastric plexus stimulators for obtaining semen from paraplegic men.

Radio-linked devices to stimulate the hypogastric plexus have been implanted into 7 patients with spinal injuries and 1 with primary anorgasmia. They caused seminal emission in all patients and still do so in the spinal injury patients. Insemination with semen thus obtained has yielded 5 pregnancies (2 live births) in the wives of 4 patients. The range of application is discussed.

Implant infections and antibiotic-impregnated silicone rubber coating.

A method is described for coating silicone rubber-encapsulated implant devices with an outer layer of silicone rubber impregnated with a mixture of gentamicin sulphate and diethanolamine fusidate. A coating of this sort provides bactericidal activity lasting for a few days in the film of fluid surrounding such an implant. When used for coating our implants, the retrospective rate of implant infections believed to have been introduced at the time of surgery was reduced to 0.7% (coated), compared with 10.0% (uncoated), a highly significant difference (p less than 0.001). Systemic perioperative antibiotic prophylaxis was not shown to confer any such benefit.

The Ferrier lecture, 1986. The actions of parasympathetic and sympathetic nerves in human micturition, erection and seminal emission, and their restoration in paraplegic patients by implanted electrical stimulators.

Implants that stimulate the S2, S3 and S4 anterior roots improve micturition, defaecation and penile erection in many patients with spinal-cord injuries. The posterior rhizotomy that is commonly done at the same time usually cures their urinary incontinence, and may greatly improve bladder compliance. Implants that stimulate the hypogastric plexus allow semen to be obtained easily from some men with spinal injuries who cannot ejaculate, and may allow an implant-driven erection. A little new knowledge about the neurophysiology of the pelvic organs has come from studying the performance of these implants.