Biomedical subjects
Publications and source records attributed to G S Brindley.
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.
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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 The electrode tip, initially to the right of the midline, was then withdrawn slightly so that it was now on the left side.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.
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.
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.
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.
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.
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.
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.
Computer-assisted methods of CT brain scan analysis offer considerable advantages over visual inspection, particularly in research; and several semi-automated methods are currently available. A new computer-assisted program is presented which provides fully automated processing of CT brain scans, depending on "anatomical knowledge" of where cerebrospinal fluid (CSF)-containing spaces are likely to lie. After identifying these regions of interest quantitative estimates are then provided of CSF content in each slice in cisterns, ventricles, Sylvian fissure and interhemispheric fissure. Separate measures are also provided of mean brain density in each slice. These estimates can be summated to provide total ventricular and total brain volumes. The program shows a high correlation with measures derived from mechanical planimetry and visual grading procedures, also when tested against a phantom brain of known ventricular volume. The advantages and limitations of the present program are discussed.
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Seven patients with azoospermia due to obstruction of the abdominal part of the vas deferens, and five paraplegic men with ejaculatory failure, were treated with implanted sperm reservoirs. In eight patients (67%) motile spermatozoa were recovered. Two pregnancies (17%) were achieved with subsequent live births (by AIH). In two patients the fertilising capacity of the spermatozoa was unsuccessful as assessed by IVF. Infection required the removal of two reservoirs.
Seven drugs that are known to relax smooth muscle (phenoxybenzamine, phentolamine, thymoxamine, imipramine, verapamil, papaverine, naftidrofuryl) caused erection when injected intracavernosally. Salbutamol, hydralazine, lignocaine and bupivacaine caused tumidity but not erection. Metaraminol and guanethidine caused shrinkage followed by tumidity. Neostigmine, atropine, propranolol and idazoxan had no effect in the doses tried. It is argued that the seven drugs that cause erection do so by relaxing vascular and trabecular smooth muscle within the cavernosal space, and that the two that cause shrinkage of the penis do so by constricting vascular and trabecular smooth muscle within the cavernosal space. It is argued that muscarinic and beta-adrenergic transmission play no important part in erectile mechanisms within the corpora cavernosa. Papaverine, phenoxybenzamine and metaraminol, given intracavernosally, are already used therapeutically. Uses are suggested for thymoxamine, phentolamine, verapamil and guanethidine.
The first 50 patients who have received sacral anterior root stimulator implants are presented, with follow-up of from 1 to 9 years. Forty-nine are alive and 43 are regularly using their implants for micturition. Of the 49 living, 39 are "very pleased, without significant reservations", six are pleased on balance but have reservations, and four are dissatisfied. Residual urine volumes are substantially reduced in all patients who are using their implants. Ten of the 12 female patients and the majority of male patients have become continent. The voiding pressure in implant-driven micturition can be regulated by adjusting the stimulus parameters, and is always kept below 90 cm H2O. Of seven patients with ureteric reflux before operation, four have ceased to reflux and the other three are unchanged. Changes in the radiographic appearances of the bladder have been favourable or zero, but there have been two cases of deterioration in the upper urinary tracts. Significant harmful effects have been CSF leaks, urinary infections following post-operative urodynamic study, and accidental damage to roots. Anterior roots nearly always recover from accidental damage, and posterior roots do not.
Intracavernosal injection of phenoxybenzamine or papaverine has been tried on 127 men suffering from erectile impotence. In 113 of them it caused an erection which should have sufficed for coitus. Seventy-three men have used such injections, given at home by themselves or their wives, fortnightly or less often, to make coitus possible after each injection; 54 of them still do so.
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