Pilot experiments on the actions of drugs injected into the human corpus cavernosum penis.

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.

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.

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.

Maintenance treatment of erectile impotence by cavernosal unstriated muscle relaxant injection.

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.

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.

Cavernosal alpha-blockade: a new technique for investigating and treating erectile impotence.

Intravacernosal injection of phenoxybenzamine, in a dose too small to have significant general effects, caused full erection lasting between half an hour and 30 hours in 30 of 4 potent men (2 normal, 2 anorgasmic) and in 6 of 11 impotent men. In the remaining potent man and 3 of the remaining eleven impotent men have had sexual intercourse, for the first time for months or years, while under the drug. The practical implications of this new discovery are discussed.

The fertility of men with spinal injuries.

Application of a vibrator of 80 Hz and 2.5 mm amplitude to the lower surface of the glans penis caused ejaculation in less than 20 minutes (usually less than 3 minutes) in 48 of 81 men with spinal cord injuries (mostly complete) of more than 6 months duration. It failed in all the 19 of the 81 who lacked reflex hip flexion on scratching the soles of the feet, and in 14 others. It failed in 11 of 12 men with injuries of less than 6 months' duration. From 21 of 34 men for whom the vibrator failed, semen could be obtained by electroejaculation, which is just as successful within 6 months of injury as subsequently and may succeed even if reflex hip flexion is absent. Eleven pregnancies where the father had a complete or nearly complete spinal cord lesion are reported. Nine healthy children have been born.

Deep scrotal temperature and the effect on it of clothing, air temperature, activity, posture and paraplegia.

Two new techniques for measuring deep scrotal temperature are described. Paraplegic men in wheelchairs have deep scrotal temperatures averaging about 0.9 degrees C higher than normal sitting men, and those whose scrotal temperatures are very high usually lack motile spermatozoa. In the author, deep scrotal temperatures at constant air temperature are 0.5 degrees C lower wearing boxer shorts than wearing Y-fronts, and 1.2 degrees C lower wearing scrotal slit underpants than wearing boxer shorts; they are 1.6 degrees C lower sitting with thighs apart than sitting with thighs together, and 0.5 degrees C lower running than sitting with thighs apart. From such observations, means of lowering paraplegic deep scrotal temperatures can be designed.

Electroejaculation: its technique, neurological implications and uses.

An improved technique for electroejaculation is described, with the results of applying it to 84 men with spinal injuries and five men with ejaculatory failure from other causes. Semen was obtained from most patients, but good semen from very few. Only one pregnancy has yet been achieved. The technique has diagnostic applications.

An implant to empty the bladder or close the urethra.

An implant has been designed which, in the baboon, will empty the bladder almost completely, or close the urethra so that urine does not leak out despite a contraction of the detrusor muscle. Electrodes on the 1st and 2nd sacral anterior nerve roots (corresponding roughly to the 3rd and 4th sacral in man) suffice for both actions. Closing the urethra or emptying the bladder artificially in this way seems to cause conscious, neurologically intact, baboons no discomfort. Implants have remained in place for over two years, and have emptied the bladder artificially 12 times a day for many weeks, without deterioration of function.

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.

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 technique for anodally blocking large nerve fibres through chronically implanted electrodes.

If a spinal root of a baboon or rhesus monkey is trapped in an initially loose-fitting silicone rubber channel containing two or more platinum electrodes, electrical pulses sent through these electrodes can stimulate nerve fibres close to the cathode and block the resulting impulses close to the anode. We show (1) how anodal break excitation and excitation of fibres outside the silicone rubber channel can be avoided; (2) that an implant 26 months old behaves like a recent one; (3) that in a root containing somatic motor fibres and parasympathetic fibres, all somatic motor fibres can be blocked and most or all parasympathetic fibres excited but not blocked; (4) that provided that the electrodes pass no net direct current, prolonged stimulation with block can be harmless; (5) how block can be achieved in one direction only along a root; (6) that a peripheral nerve can be blocked by the same techniques.