260
BRITISH MEDICAL JOURNAL
were not treated at Hammersmith Hospital. This feature of the trial arose from the collaboration with other hospitals to ensure an adequate total intake. When a patient, first seen at another hospital, was allocated at random to receive conventional treatment it was often difficult to justify giving that treatment at Hammersmith rather than at the hospital of origin. A comparison of the response of patients treated with photons at Hammersmith with those patients in the neutron series who would have received their treatment at Hammersmith, whichever form of treatment had been selected, was included in the first report on the trial.' The findings in this subtrial at September 1976 were as shown in the accompanying table. The findings in the subtrial are similar Findings in subtrial of neutron and photon treatment at September 1976
Local control of tumour: No with continued complete regression No with complete regression followed by recurrence No with no or incomplete regression Survival: °, alive at 1 year (actuarial) Additional treatment for suspected residual disease: No given radiotherapy No treated surgically No with severe complications in larynx or pharynx Mean time-dosefactor (TDF)
Neutron series (n = 20)
Photon series (n = 25)
18
5
2
12
54
38
8
3
3 3 118
1 108
to those for the whole trial. The difference between the numbers with persisting local control is significant at the 0-1 % level; the difference in mortality rates is not significant. In the subtrial the average time-dose factor (TDF) was about 10% higher for patients in the neutron series than for those in the photon series (compared with about 20 % in the whole trial'). Nevertheless, as the reports of both trials indicate, persistent local control of the tumour among subgroups of patients who were receiving equivalent doses of the two types of radiation was much more frequent among the neutron-treated patients. We hope that many of the difficulties of a multicentre trial will be avoided in the new trials which will be undertaken with the cyclotron which has recently been installed at the Westem General Hospital, Edinburgh. Finally, we would like to correct a misprint in the table in our more recent article (25 June, p 1642). Ten, not 16, neutron patients received supplementary surgery for suspected residual disease. MARY CATTERALL D K BEWLEY MRC Cyclotron Unit, Hammersmith Hospital, London W12
IAN SUTHERLAND MRC Statistical Research and Services Unit, London WC1
'Catterall, M, Sutherland, I, and Bewley, D K, British Medical Journal, 1975, 2, 653.
Relative activity of atenolol and metoprolol SIR,-With the increasing interest in the clinical use of cardioselective P-adrenergic
antagonists it is of fundamental importance that the relative potency of the individual compounds be established. Using propranolol as the reference substance, it has been shown that the ratio between equipotent doses of atenolol and propranololl is 1:0-7 and that of metoprolol and propranolol2 1:0 8. These results would suggest that identical doses of the two selective 5,-receptor antagonists, atenolol and metoprolol, would give the same degree of 5-blockade. To test this hypothesis we have compared the 3-blocking effects of the two drugs in a group of seven hypertensive patients who, after one week's placebo treatment, were given in random order, one week's treatment with atenolol 100 mg daily, atenolol 200 mg daily, metoprolol 100 mg daily, and metoprolol 200 mg daily. At the end of each treatment period an exercise test on a bicycle ergometer (5 min at 75 W) was carried out two hours after tablet administration, heart rate and blood pressure recordings being taken before, during, and after exercise. Mean results on placebo showed a resting heart rate of 98/min and a resting blood pressure of 170/105 mm Hg rising to 145/min and 221/111 mm Hg at the end of exercise. The respective values after atenolol 100 mg were 59/min, 161/99 mm Hg, 96/min, and 188/106 mm Hg and after metoprolol 100 mg they were 61/min, 161/102 mm Hg, 97/min, and 195/110 mm Hg. After atenolol 200 mg the respective values were 63/min, 161/97 mm Hg, 92/min, and 191/105 mm Hg and after metoprolol 200 mg they were 62/min, 163/97 mm Hg, 93/min, and 189/104 mm Hg. This similar degree in the inhibition of exercise tachycardia following both 100 mg and 200 mg administration suggests the equipotency of these two compounds. It is also interesting that no significant difference was observed in the hypotensive effects of these compounds at rest and on cessation of exercise.
23 JULY 1977
Of the adults taking maprotiline, 17 had' ingested more than 1 g and 10 less than 1 g, and in nine cases the amount ingested was not known; 10 patients had taken additional drugs. All but two of these patients developed symptoms. These, in order of frequency, were: drowsiness in 24 cases, convulsions in eight, coma in seven, anticholinergic signs in five, tachycardia in five, bradycardia in three, cardiac arrest in three, hypotension in two, and hypertension in one. Two of the patients died, but their deaths were not directly attributable to the overdose; one died of a massive pulmonary embolus after making a full recovery from the overdose and the other died from a fall following the overdose. Two of the five children who took maprotiline developed symptoms. One was just drowsy, while the other, a girl of 4, had repeated convulsions after the ingestion of 525 mg of the drug. The symptoms reported in the 19 adults who ingested mianserin were drowsiness in 13 cases, hypertension in three, coma id two, tachycardia in two, and hypotension in one. There were no reports of cardiac arrhythmias or convulsions. The two patients who were in coma had taken additional sedative drugs. There was one death. This patient, a woman of 72, had threatened suicide previously. She was admitted deeply unconscious having ingested about 600 mg of mianserin and an unknown quantity of lorazepam. She did not regain consciousness and died the next day. Necropsy revealed bronchopneumonia. Toxicological analysis confirmed that only these two drugs had been ingested. The plasma mianserin concentration on admission was 110 lg/l and that of lorazepam 500 ,ug/l. From our as yet limited experience it would appear that the clinical features of poisoning with these two compounds differ. Overdose of maprotiline causes symptoms similar to those produced by the more conventional tricyclic antidepressants2 and our findings are in accord with those reported by Drs Park and Proudfoot. M BRIAN COMERFORD Overdose of mianserin commonly causes E M M BESTERMAN drowsiness but the more serious complications of tricyclic antidepressant poisoning (conWaller Cardio Pulmonary Unit, St Mary's Hospital, vulsions and cardiac arrhythmias) were not London W2 reported. It is possible that if these patients 'De Plaen, J F, Amery, A, and Reybrouck, T, European had taken larger quantities of mianserin they Journal of Clinical Pharmacology, 1976, 10, 297. 2 Bengtsson, C, Acta Medica Scandinavica, 1976, 199, would have exhibited more serious symptoms. The absence of anticholinergic effects with 71. mianserin would suggest that physostigmine or other cholinesterase inhibitors should not Poisoning with maprotiline and be used in therapy. mianserin We would like to thank all those physicians who our questionnaires and Dr Ian Bradbrook completed SIR,-Since the introduction of tricyclic anti- for the mianserin estimations. depressant drugs into clinical practice 20 years PETER CROME ago they have become an increasingly popular BELINDA NEWMAN agent for suicide and self-poisoning. In 1974, New Cross Hospital Poisons Unit, the latest year for which figures are available, London SE14 there were 323 deaths attributed to these Office of Population Censuses and Surveys, Deaths drugs,' and this number has probably infrom Poisoning by Solid and Liquid Substances, 1974, creased since then. In order to ascertain the London, OPCS, 1976. J, and Mathew, H, Clinical Toxicology, 1969, incidence of serious toxicity from overdose we 'Noble, 2, 403. have followed up all cases of antidepressant poisoning referred to this unit in the year starting April 1976. Although analysis of this study is not yet complete, the report by Drs Whooping-cough immunisation J Park and A T Proudfoot (18 June, p 1573) prompts us to report our experience of over- SIR,-As stated in your leading article (2 July, dose with the two newly introduced quadri- p 5), there have been differences in the esticyclic antidepressants, maprotiline (Ludiomil) mates of the risks which may be associated and mianserin (Bolvidon; Norval). Follow-up with whooping-cough vaccine. As I have prewas achieved on 41 cases (36 in adults and five viously pointed out, in evaluating the vaccines in children) of maprotiline poisoning and 20 available today "it is not acceptable to extracases (19 in adults and one in a child) of polate from data collected from studies with mianserin poisoning. other vaccines and different schedules, or from
BRITISH MEDICAL JOURNAL
other countries at different times."'I My paper,2 to which you made reference, related to vaccines which were tested in the early 1960s.3 It is impossible, as you say, to come to any accurate judgment of the risk of the presently available vaccines. It would appear, however, from the unpublished evidence of Pollock4 that current vaccines are less reactogenic than -those which we studied in the past.' GEORGE DICK London NW1
3
261
23 JULY 1977
Dick, G, General Practitioner, 1977, 6 May, p 34. Dick, G, Proceedings of the Royal Society of Medicine, 1974, 67, 371. Haire, M, Dane, D S, and Dick, G, Medical Officer, 1967, 117, 55. Department of Health and Social Security, Whooping Cough Vaccination, para 59. London, HMSO, 1977.
SIR,-Why are you (2 July, p 5) so ready to accept all the contraindications to whoopingcough vaccination restated by the Joint Committee on Vaccination and Immunisation? Have you calculated what percentage of the infant population will be excluded from the right to vaccination because of a history or history of everything from epilepsy to Jfamily Ianoxic convulsions,' not to mention the expenditure of doctors' and nurses' time ? Are you aware of any new data showing that neurological disorder predisposes to vaccineinduced brain damage ? If so please draw it to our attention, because at the time of Prensky's penetrating review2 there was no evidence that withstood critical analysis. In the absence of a proved causal connection between vaccination and the eventual handicap arising from a pre-existing neurological disorder the only justification for avoiding vaccination in such cases is to save the State the embarrassment and expense of a compensation suit. But, as pointed out elsewhere,3 the compensation proposals make it to every suspect "braindamaged" infant's financial advantage to be vaccinated as quickly as possible. J B P STEPHENSON Fraser of Allander Unit, Royal Hospital for Sick Children, Glasgow
Gastaut, H, and Gastaut, Y, Electroencephalography and Clinical Neurophysiology, 1958, 10, 607. Neurology, 1974, 16, 539. sStephenson, J B P, Lancet, 1977, 2, 34.
2 Prensky, A L, Developmental Medicine and Child
Stress incontinence
SIR,-The conviction that urologists should become more involved in the management of female incontinence has led to the creation of a joint uro-gynaecological urodynamic clinic within the urodynamic service provided in this hospital by the urology department. Your leading article (2 July, p 2) was therefore of particular interest. There were, however, some surprising omissions and opinions requiring comment. Simple voiding cinecystography should be possible in most teaching hospitals, but only a few specialised urodynamic services, of which this is one, are able to combine pressure flow studies with voiding cystography. The equipment is expensive and a sizable multidisciplinary team is required. Cystometry was not mentioned, although it should be within the capability of most district
general hospitals. It is an essential component of combined studies and by itself is better able to detect abnormalities of detrusor function than any other simple investigation available to the average clinic. Continuous filling with simultaneous recording of intravesical pressure is easier and more accurate than the traditional incremental manometry. A single transducer and recording channel would suffice. Urethral closure pressure profile (UCPP) measurement is also useful, although it requires a further transducer and recording channel. This investigation has not gained wide recognition, probably owing to oversimplification of technique. UCPP measurement is unreliable unless (a) intravesical pressure is recorded throughout, since pathological detrusor activity may temporarily reduce UCPP values, and (b) the volume of fluid in the bladder is also known, since patients with pelvic floor weakness tend to show deterioration in UCPP as the bladder reaches maximum capacity whereas in the normal the values are unchanged or increase.' Measurement and interpretation of UCPP require more expertise than cystometry and it is best restricted to specialised departments. You make no mention of either training exercises or electrical muscle stimulation, while advocating artificial sphincters for the "few women in whom there is no apparent underlying vesical problem and in whom surgery has completely failed." Electrical stimulation has been shown to be effective.2 Patient-operated muscle stimulators employing anal plug or vaginal pessary electrodes are relatively inexpensive; are safe; and do not require surgery.3 Indeed, a trial period of stimulation for those on the waiting list for surgery might reduce the need for operation with resulting benefit to the patient and hospital economy. Artificial sphincters are expensive, require specialised major surgery, and have yet to stand the test of time, as your earlier leading article (29 January, p 254) made clear. ERIC S GLEN Department of Urology, Southern General Hospital, Glasgow Glen, E S, and Rowan, D, Urological Research, 1973, 1, 97. De Backer, E, Proceedings of 16th Congress of the International Society of Urology, 1973, vol 1, p 191. 3Glen, E S, in Urinary Incontinence, ed K P S Caldwell, p 89. London, Pitman Medical, 1975.
measurements of angles. Indeed, the voiding cystogram without pressure studies gives very little more information. Using videotape to record simultaneous voiding cystourethrograms and intrinsic bladder pressure and urine flow measurements is preferable as it allows instant replay with the additional facility of reusing the videotape for other recordings, whereas cine film needs processing and is disadvantageous in terms of cost and time. The figures quoted for the success of vaginal repair for the control of incontinence are wildly optimistic. Bailey,' Jeffcoate,2 and Low3 quote failure rates of between 37 and 52 %. Suprapubic procedures (such as the Marshall-Marchetti-Krantz and the Burch colposuspension operation) achieve a higher success rate and, as the first operation has a greater chance of success than subsequent operations, there is much to commend a suprapubic operation as a primary procedure. The practice of this unit4 is to perform only suprapubic surgery for control of incontinence and to use the vaginal repair with or without hysterectomy for prolapse only when it is uncomplicated by incontinence or when residual prolapse still remains following suprapubic surgery. Genital prolapse should be of secondary consideration in the management of urinary incontinence. The criteria for investigation of incontinence should not depend on whether prolapse is present or not but rather on the following: (1) The present symptoms and signs. Stress incontinence with urgency, frequency, incontinence on change of position, or signs of motor neurone disease demands investigation to exclude detrusor instability or other bladder disorders. Where simple stress incontinence occurs without any complications the patient does not need elaborate investigation and responds well to continence surgery. (2) Previous failed continence surgery, where investigation is required to define if possible the reasons for failure and to exclude detrusor instability, which responds poorly to surgery. Finally, the artificial sphincter, while offering relief to many patients, is not without complications, as with any implanted foreign body. This must be made clear to the patient beforehand and seen in the light of alternative procedures such as urinary diversion.
2
SIR,-Your leading article (2 July, p 2) on this subject raises many controversial points. The mechanism of urethral sphincteric action is imperfectly understood, but it is likely that the main factor in the control of continence is elevation of the urethrovesical junction into the abdominal zone of pressure. The distal sphincter mechanism or the external urethral sphincter is of secondary importance in the female. Central to a modern urodynamic concept of urinary incontinence is the recognition that it has a multifactorial aetiology and requires the multidisciplinary team approach of a urologist, gynaecologist, radiologist, neurologist, and physicist supplemented by nursing and technical help. The mainstay of modern investigation is measurement of the intrinsic bladder pressure (which is the total bladder pressure minus the abdominal pressure). Opinion has very definitely veered away from the use of static voiding radiographs and
STUART STANTON Department of Obstetrics and Gynaecology, St George's Hospital Medical School, London SW17 1 Bailey, K V, Journal of Obstetrics and Gynaecology of the British Empire, 1954, 61, 291. 2 Jeffcoate, N, British journal of Urology, 1965, 37, 633. 3 Low, J A, American Journal of Obstetrics and Gynecology, 1967, 97, 308. 4 Stanton, S L, Williams, J E, and Ritchie, D, British Journal of Obstetrics and Gynaecology, 1976, 83, 890.
SIR,-Your leading article on this subject (2 July, p 2) suggests that women with a vaginal prolapse and an unstable detrusor must be warned that the operation of pelvic floor repair may not effect a cure. Since I have the benefit of cystourethrometry before surgery I am able to diagnose the cause of the incontinence in the majority of cases. I am also able to perform vesical overdistension immediately after repair, when the detrusor is thought to be unstable, and to date this combined procedure has been most successful. P I SILVERSTONE Royal Victoria Infirmary, Newcastle upon Tyne
BRITISH MEDICAL JOURNAL
were not treated at Hammersmith Hospital. This feature of the trial arose from the collaboration with other hospitals to ensure an adequate total intake. When a patient, first seen at another hospital, was allocated at random to receive conventional treatment it was often difficult to justify giving that treatment at Hammersmith rather than at the hospital of origin. A comparison of the response of patients treated with photons at Hammersmith with those patients in the neutron series who would have received their treatment at Hammersmith, whichever form of treatment had been selected, was included in the first report on the trial.' The findings in this subtrial at September 1976 were as shown in the accompanying table. The findings in the subtrial are similar Findings in subtrial of neutron and photon treatment at September 1976
Local control of tumour: No with continued complete regression No with complete regression followed by recurrence No with no or incomplete regression Survival: °, alive at 1 year (actuarial) Additional treatment for suspected residual disease: No given radiotherapy No treated surgically No with severe complications in larynx or pharynx Mean time-dosefactor (TDF)
Neutron series (n = 20)
Photon series (n = 25)
18
5
2
12
54
38
8
3
3 3 118
1 108
to those for the whole trial. The difference between the numbers with persisting local control is significant at the 0-1 % level; the difference in mortality rates is not significant. In the subtrial the average time-dose factor (TDF) was about 10% higher for patients in the neutron series than for those in the photon series (compared with about 20 % in the whole trial'). Nevertheless, as the reports of both trials indicate, persistent local control of the tumour among subgroups of patients who were receiving equivalent doses of the two types of radiation was much more frequent among the neutron-treated patients. We hope that many of the difficulties of a multicentre trial will be avoided in the new trials which will be undertaken with the cyclotron which has recently been installed at the Westem General Hospital, Edinburgh. Finally, we would like to correct a misprint in the table in our more recent article (25 June, p 1642). Ten, not 16, neutron patients received supplementary surgery for suspected residual disease. MARY CATTERALL D K BEWLEY MRC Cyclotron Unit, Hammersmith Hospital, London W12
IAN SUTHERLAND MRC Statistical Research and Services Unit, London WC1
'Catterall, M, Sutherland, I, and Bewley, D K, British Medical Journal, 1975, 2, 653.
Relative activity of atenolol and metoprolol SIR,-With the increasing interest in the clinical use of cardioselective P-adrenergic
antagonists it is of fundamental importance that the relative potency of the individual compounds be established. Using propranolol as the reference substance, it has been shown that the ratio between equipotent doses of atenolol and propranololl is 1:0-7 and that of metoprolol and propranolol2 1:0 8. These results would suggest that identical doses of the two selective 5,-receptor antagonists, atenolol and metoprolol, would give the same degree of 5-blockade. To test this hypothesis we have compared the 3-blocking effects of the two drugs in a group of seven hypertensive patients who, after one week's placebo treatment, were given in random order, one week's treatment with atenolol 100 mg daily, atenolol 200 mg daily, metoprolol 100 mg daily, and metoprolol 200 mg daily. At the end of each treatment period an exercise test on a bicycle ergometer (5 min at 75 W) was carried out two hours after tablet administration, heart rate and blood pressure recordings being taken before, during, and after exercise. Mean results on placebo showed a resting heart rate of 98/min and a resting blood pressure of 170/105 mm Hg rising to 145/min and 221/111 mm Hg at the end of exercise. The respective values after atenolol 100 mg were 59/min, 161/99 mm Hg, 96/min, and 188/106 mm Hg and after metoprolol 100 mg they were 61/min, 161/102 mm Hg, 97/min, and 195/110 mm Hg. After atenolol 200 mg the respective values were 63/min, 161/97 mm Hg, 92/min, and 191/105 mm Hg and after metoprolol 200 mg they were 62/min, 163/97 mm Hg, 93/min, and 189/104 mm Hg. This similar degree in the inhibition of exercise tachycardia following both 100 mg and 200 mg administration suggests the equipotency of these two compounds. It is also interesting that no significant difference was observed in the hypotensive effects of these compounds at rest and on cessation of exercise.
23 JULY 1977
Of the adults taking maprotiline, 17 had' ingested more than 1 g and 10 less than 1 g, and in nine cases the amount ingested was not known; 10 patients had taken additional drugs. All but two of these patients developed symptoms. These, in order of frequency, were: drowsiness in 24 cases, convulsions in eight, coma in seven, anticholinergic signs in five, tachycardia in five, bradycardia in three, cardiac arrest in three, hypotension in two, and hypertension in one. Two of the patients died, but their deaths were not directly attributable to the overdose; one died of a massive pulmonary embolus after making a full recovery from the overdose and the other died from a fall following the overdose. Two of the five children who took maprotiline developed symptoms. One was just drowsy, while the other, a girl of 4, had repeated convulsions after the ingestion of 525 mg of the drug. The symptoms reported in the 19 adults who ingested mianserin were drowsiness in 13 cases, hypertension in three, coma id two, tachycardia in two, and hypotension in one. There were no reports of cardiac arrhythmias or convulsions. The two patients who were in coma had taken additional sedative drugs. There was one death. This patient, a woman of 72, had threatened suicide previously. She was admitted deeply unconscious having ingested about 600 mg of mianserin and an unknown quantity of lorazepam. She did not regain consciousness and died the next day. Necropsy revealed bronchopneumonia. Toxicological analysis confirmed that only these two drugs had been ingested. The plasma mianserin concentration on admission was 110 lg/l and that of lorazepam 500 ,ug/l. From our as yet limited experience it would appear that the clinical features of poisoning with these two compounds differ. Overdose of maprotiline causes symptoms similar to those produced by the more conventional tricyclic antidepressants2 and our findings are in accord with those reported by Drs Park and Proudfoot. M BRIAN COMERFORD Overdose of mianserin commonly causes E M M BESTERMAN drowsiness but the more serious complications of tricyclic antidepressant poisoning (conWaller Cardio Pulmonary Unit, St Mary's Hospital, vulsions and cardiac arrhythmias) were not London W2 reported. It is possible that if these patients 'De Plaen, J F, Amery, A, and Reybrouck, T, European had taken larger quantities of mianserin they Journal of Clinical Pharmacology, 1976, 10, 297. 2 Bengtsson, C, Acta Medica Scandinavica, 1976, 199, would have exhibited more serious symptoms. The absence of anticholinergic effects with 71. mianserin would suggest that physostigmine or other cholinesterase inhibitors should not Poisoning with maprotiline and be used in therapy. mianserin We would like to thank all those physicians who our questionnaires and Dr Ian Bradbrook completed SIR,-Since the introduction of tricyclic anti- for the mianserin estimations. depressant drugs into clinical practice 20 years PETER CROME ago they have become an increasingly popular BELINDA NEWMAN agent for suicide and self-poisoning. In 1974, New Cross Hospital Poisons Unit, the latest year for which figures are available, London SE14 there were 323 deaths attributed to these Office of Population Censuses and Surveys, Deaths drugs,' and this number has probably infrom Poisoning by Solid and Liquid Substances, 1974, creased since then. In order to ascertain the London, OPCS, 1976. J, and Mathew, H, Clinical Toxicology, 1969, incidence of serious toxicity from overdose we 'Noble, 2, 403. have followed up all cases of antidepressant poisoning referred to this unit in the year starting April 1976. Although analysis of this study is not yet complete, the report by Drs Whooping-cough immunisation J Park and A T Proudfoot (18 June, p 1573) prompts us to report our experience of over- SIR,-As stated in your leading article (2 July, dose with the two newly introduced quadri- p 5), there have been differences in the esticyclic antidepressants, maprotiline (Ludiomil) mates of the risks which may be associated and mianserin (Bolvidon; Norval). Follow-up with whooping-cough vaccine. As I have prewas achieved on 41 cases (36 in adults and five viously pointed out, in evaluating the vaccines in children) of maprotiline poisoning and 20 available today "it is not acceptable to extracases (19 in adults and one in a child) of polate from data collected from studies with mianserin poisoning. other vaccines and different schedules, or from
BRITISH MEDICAL JOURNAL
other countries at different times."'I My paper,2 to which you made reference, related to vaccines which were tested in the early 1960s.3 It is impossible, as you say, to come to any accurate judgment of the risk of the presently available vaccines. It would appear, however, from the unpublished evidence of Pollock4 that current vaccines are less reactogenic than -those which we studied in the past.' GEORGE DICK London NW1
3
261
23 JULY 1977
Dick, G, General Practitioner, 1977, 6 May, p 34. Dick, G, Proceedings of the Royal Society of Medicine, 1974, 67, 371. Haire, M, Dane, D S, and Dick, G, Medical Officer, 1967, 117, 55. Department of Health and Social Security, Whooping Cough Vaccination, para 59. London, HMSO, 1977.
SIR,-Why are you (2 July, p 5) so ready to accept all the contraindications to whoopingcough vaccination restated by the Joint Committee on Vaccination and Immunisation? Have you calculated what percentage of the infant population will be excluded from the right to vaccination because of a history or history of everything from epilepsy to Jfamily Ianoxic convulsions,' not to mention the expenditure of doctors' and nurses' time ? Are you aware of any new data showing that neurological disorder predisposes to vaccineinduced brain damage ? If so please draw it to our attention, because at the time of Prensky's penetrating review2 there was no evidence that withstood critical analysis. In the absence of a proved causal connection between vaccination and the eventual handicap arising from a pre-existing neurological disorder the only justification for avoiding vaccination in such cases is to save the State the embarrassment and expense of a compensation suit. But, as pointed out elsewhere,3 the compensation proposals make it to every suspect "braindamaged" infant's financial advantage to be vaccinated as quickly as possible. J B P STEPHENSON Fraser of Allander Unit, Royal Hospital for Sick Children, Glasgow
Gastaut, H, and Gastaut, Y, Electroencephalography and Clinical Neurophysiology, 1958, 10, 607. Neurology, 1974, 16, 539. sStephenson, J B P, Lancet, 1977, 2, 34.
2 Prensky, A L, Developmental Medicine and Child
Stress incontinence
SIR,-The conviction that urologists should become more involved in the management of female incontinence has led to the creation of a joint uro-gynaecological urodynamic clinic within the urodynamic service provided in this hospital by the urology department. Your leading article (2 July, p 2) was therefore of particular interest. There were, however, some surprising omissions and opinions requiring comment. Simple voiding cinecystography should be possible in most teaching hospitals, but only a few specialised urodynamic services, of which this is one, are able to combine pressure flow studies with voiding cystography. The equipment is expensive and a sizable multidisciplinary team is required. Cystometry was not mentioned, although it should be within the capability of most district
general hospitals. It is an essential component of combined studies and by itself is better able to detect abnormalities of detrusor function than any other simple investigation available to the average clinic. Continuous filling with simultaneous recording of intravesical pressure is easier and more accurate than the traditional incremental manometry. A single transducer and recording channel would suffice. Urethral closure pressure profile (UCPP) measurement is also useful, although it requires a further transducer and recording channel. This investigation has not gained wide recognition, probably owing to oversimplification of technique. UCPP measurement is unreliable unless (a) intravesical pressure is recorded throughout, since pathological detrusor activity may temporarily reduce UCPP values, and (b) the volume of fluid in the bladder is also known, since patients with pelvic floor weakness tend to show deterioration in UCPP as the bladder reaches maximum capacity whereas in the normal the values are unchanged or increase.' Measurement and interpretation of UCPP require more expertise than cystometry and it is best restricted to specialised departments. You make no mention of either training exercises or electrical muscle stimulation, while advocating artificial sphincters for the "few women in whom there is no apparent underlying vesical problem and in whom surgery has completely failed." Electrical stimulation has been shown to be effective.2 Patient-operated muscle stimulators employing anal plug or vaginal pessary electrodes are relatively inexpensive; are safe; and do not require surgery.3 Indeed, a trial period of stimulation for those on the waiting list for surgery might reduce the need for operation with resulting benefit to the patient and hospital economy. Artificial sphincters are expensive, require specialised major surgery, and have yet to stand the test of time, as your earlier leading article (29 January, p 254) made clear. ERIC S GLEN Department of Urology, Southern General Hospital, Glasgow Glen, E S, and Rowan, D, Urological Research, 1973, 1, 97. De Backer, E, Proceedings of 16th Congress of the International Society of Urology, 1973, vol 1, p 191. 3Glen, E S, in Urinary Incontinence, ed K P S Caldwell, p 89. London, Pitman Medical, 1975.
measurements of angles. Indeed, the voiding cystogram without pressure studies gives very little more information. Using videotape to record simultaneous voiding cystourethrograms and intrinsic bladder pressure and urine flow measurements is preferable as it allows instant replay with the additional facility of reusing the videotape for other recordings, whereas cine film needs processing and is disadvantageous in terms of cost and time. The figures quoted for the success of vaginal repair for the control of incontinence are wildly optimistic. Bailey,' Jeffcoate,2 and Low3 quote failure rates of between 37 and 52 %. Suprapubic procedures (such as the Marshall-Marchetti-Krantz and the Burch colposuspension operation) achieve a higher success rate and, as the first operation has a greater chance of success than subsequent operations, there is much to commend a suprapubic operation as a primary procedure. The practice of this unit4 is to perform only suprapubic surgery for control of incontinence and to use the vaginal repair with or without hysterectomy for prolapse only when it is uncomplicated by incontinence or when residual prolapse still remains following suprapubic surgery. Genital prolapse should be of secondary consideration in the management of urinary incontinence. The criteria for investigation of incontinence should not depend on whether prolapse is present or not but rather on the following: (1) The present symptoms and signs. Stress incontinence with urgency, frequency, incontinence on change of position, or signs of motor neurone disease demands investigation to exclude detrusor instability or other bladder disorders. Where simple stress incontinence occurs without any complications the patient does not need elaborate investigation and responds well to continence surgery. (2) Previous failed continence surgery, where investigation is required to define if possible the reasons for failure and to exclude detrusor instability, which responds poorly to surgery. Finally, the artificial sphincter, while offering relief to many patients, is not without complications, as with any implanted foreign body. This must be made clear to the patient beforehand and seen in the light of alternative procedures such as urinary diversion.
2
SIR,-Your leading article (2 July, p 2) on this subject raises many controversial points. The mechanism of urethral sphincteric action is imperfectly understood, but it is likely that the main factor in the control of continence is elevation of the urethrovesical junction into the abdominal zone of pressure. The distal sphincter mechanism or the external urethral sphincter is of secondary importance in the female. Central to a modern urodynamic concept of urinary incontinence is the recognition that it has a multifactorial aetiology and requires the multidisciplinary team approach of a urologist, gynaecologist, radiologist, neurologist, and physicist supplemented by nursing and technical help. The mainstay of modern investigation is measurement of the intrinsic bladder pressure (which is the total bladder pressure minus the abdominal pressure). Opinion has very definitely veered away from the use of static voiding radiographs and
STUART STANTON Department of Obstetrics and Gynaecology, St George's Hospital Medical School, London SW17 1 Bailey, K V, Journal of Obstetrics and Gynaecology of the British Empire, 1954, 61, 291. 2 Jeffcoate, N, British journal of Urology, 1965, 37, 633. 3 Low, J A, American Journal of Obstetrics and Gynecology, 1967, 97, 308. 4 Stanton, S L, Williams, J E, and Ritchie, D, British Journal of Obstetrics and Gynaecology, 1976, 83, 890.
SIR,-Your leading article on this subject (2 July, p 2) suggests that women with a vaginal prolapse and an unstable detrusor must be warned that the operation of pelvic floor repair may not effect a cure. Since I have the benefit of cystourethrometry before surgery I am able to diagnose the cause of the incontinence in the majority of cases. I am also able to perform vesical overdistension immediately after repair, when the detrusor is thought to be unstable, and to date this combined procedure has been most successful. P I SILVERSTONE Royal Victoria Infirmary, Newcastle upon Tyne
