Publication history, Reflections & comments
In our culture, endemic obesity is due to the habit of over-eating. This behavioural problem is treated by many methods. The limited success of dental wiring suggests it is worth trying to interfere at some other point in the appetite/eating chain.
The simplicity of the idea of inflating a balloon in the stomach to reduce appetite is appealing, and seemed worth testing. Suitable equipment was developed, and a trial carried out on 31 patients at the Whyalla Hospital over 12 months in 1982.
Results of this trial were reported at a grand round of the Department of Surgery at the Flinders Medical Centre on December 12, 1982. They are repeated here, together with experience of three further models of balloon. Formal publication of this experience has been avoided so far, because of the likelihood of misreporting and trivialisation by the popular media.
MethodThe ethical opinion of doctors at the Whyalla Hospital and surgeons practising obesity surgery in Australia was sought. Their advice was to proceed. By trial and error a suitable neoprene balloon was designed in conjunction with Ansell Australia, and assembled with a thin silastic filling tube.
Fifty balloons were inserted in 31 patients. All noticed satiety with smaller meals than normal while the balloon was intact. 4 patients had the balloon removed within one day at their request. Weight loss averaged 0.87 kg. per week over-all, and 1.28 kg. per week for the time it was considered the balloon was intact. Average time per balloon was between 2 and 3 weeks, with a wide spread. Average weight loss was 5.6 kg., also with a wide spread.
One of the two authors had such a balloon in place for 3 weeks, losing weight from 80 to 71 kg. in that time. He was unusually highly motivated, and cannot be regarded as typical. Conflict of appetite signals was a striking feature, with different messages from brain, eye, nose, mouth, and stomach. With poetic justice, the balloon became detached on attempted removal, remained partly inflated causing abdominal colic, and required removal at gastroscopy by the other author of this paper.
There were several other cases of severe cramp till balloon volume was decreased, and a few requiring gastroscopic removal of the balloon. A number of other patients passed a detached balloon through the bowel, retrieving it for examination by the investigators.
Three major complications occurred. These were one episode of inhaled gastric contents requiring overnight ventilation and attributed to over-heavy sedation, and 2 cases of small bowel obstruction due to incompletely deflated balloons, requiring enterotomy. In these two cases, one balloon was removed at planned gastric by-pass, and the other required laparotomy with a post-operative hospital stay of 5 days. This complication is considered avoidable since changing the design of the connector between balloon and tubing from fine polythelene, which would kink, to specially machined little grommets of a rigid plastic material like solid nylon.
The preceding observations were regarded at the time as forming a closed trial, with numerical data as a basis for further organised studies.
In 1983, patients were subjected to trial of balloon on 9 further occasions, of a more experimental nature, and these are now presented:
1. Thickened vulcanised neoprene. Three balloons of this description, kindly provided by Ansell International, were assembled and introduced, but each one broke within a few days, much more quickly than if not vulcanised. Each was withdrawn without bother. Failure was probably due to weakening, rather than the chemical and mechanical strengthening hoped for with this change.
2. Silastic balloons. Three prototypes of a model being used for a series of large trials in North America were made available by the manufacturing company. They were adapted from inflatable breast implants. Possibly because of a misunderstanding by one of the authors of the way the balloon was bonded to the tubing, all three balloons leaked. They were bulkier than the rubber ones,and one patient required a general anaesthetic for gastroscopic removal, as ordinary sedation had still left the cardia too tight to allow its withdrawal.
3. Nitryl balloons. It had become clear that the main problem with the neoprene balloons was their chemical deterioration in the stomach. The responsible factor was unlikely to be acid, as neoprene is quite resistant to strong acids. Enquiries to rubber chemists throughout Australia, by telephone, suggested the likely culprit was animal fat in the diet, as fats and greases commonly attack most kinds of rubber. One kind of rubber, called nitryl rubber, is resistant to fats. It is used in the abattoir industry both for rubber gloves and for rollers. It is more brittle and less elastic than latex or neoprene, but can be bonded on to them.
A number of nitryl balloons were made up by Ansell for further trial. Three of them were inserted, a second one being in one patient where the first one failed quickly. All leaked quickly, not from deterioration of the rubber as with the earlier balloons, but from next to the knot sealing over the original neck of the balloon, opposite to the connection to the tube.
The failure seems to have been a simple mechanical one, from tight tying with dacron thread which had cut through the more brittle nitryl rubber while this had not occurred with the neoprene. This seems a simple problem to overcome with the very next balloon to be made up. By good luck, one of the three balloons was kept in place in the stomach for two weeks despite lack of effect on the appetite, indicating it had leakoa. It was saved for examination after removal. There was no deterioration of the strength of the rubber, and the only
abnormality noted was a discolouration of its surface. Nitryl rubber seems suited for use in the stomach, and it may be used as an outer coating for ballons made of neoprene if this seems desirable.
The balloon method of appetite control in obesity is promising if not proven for periods longer than about three weeks. There is no doubt in the minds of the authors that a balloon has the valid and reliable effect of giving satiety signals from the stomach. Long-term follow-up of weight and changed eating habits is necessary, as well as improvements in the equipment used. However it seems that the techniques developed for balloon assembly, and for insertion, are quite adequate. Only the balloon material has been a problem, and this is quite likely now solved.
Similar techniques have been tried at several places abroad. In Copenhagen, 2 gastro-enterologists reported their results in 5 patients in the Lancet in January 1982. While they were atisfied with the validity of the method, they had the problem of their latex balloons deteriorating and failing after only a few days. In Canada, Dr. Walter Percival has been working closely with Dow Corning, and has experience with well over 60 patients at last contact almost a year ago. He has not yet published, to our knowledge, and the last news from Dow Corning a few weeks ago was that further improvements were being carried out to the balloon. Some brief clinical reports of a similar technique appeared in German, but these have not been translated, and advice has been they are not helpful. The Whyalla technique differs from others mainly in that it relies on a smaller volume, of water rather than air, to occupy the antrum rather than the fundus of the stomach.
Worries about gastrin
Because of a report of gastric ulcers in rats with simulated gastric balloons, paired serum gastrin measurements were made, but these were all in the normal range. One mild duodenal ulcer, not causing symptoms, was found at gastroscopy for removing a balloon, but no other signs have been observed of local irritation. Indeed one striking observation (by G.T.) in two patients was relief of symptoms from a hiatus hernia..
Such studies provide unique opportunities for clinical research into mechanisms of gastric empty‑ing, secretion of gastrin, cholecystokinin and other neuropeptides, and into behavioural psychology, quite apart from any clinical value. If proved valid and safe, this technique may become a valuable addition to the methods now used for managing obesity. For the present, it must be assessed carefully in units undertaking research in gastro-enterology and obesity.
Detailed information of the present technique is available in booklets written for patients, referring doctors, and treating physicians. These have been prepared for purposes of current studies rather than for general use.
Given a favourable consensus, it is hoped to continue clinical trials both at Whyalla and elsewhere, and to pursue studies mentioned above. It would be an advantage if some of the subjects were obese doctors.
At this stage there is a problem of logistics in Whyalla. Nearly all the equipment design and assembly, organisation of doctors and patients, and the large amounts of documentation, correspondence, and much telephoning, have been done by one person in time between a busy private practice and commitments including other basic research. It would be good to share the coming likely success, and also the load of work leading up to it.
AN INTRA-GASTRIC BALLOON FOR APPETITE CONTROL AND RE-EDUCATION IN OBESITY: CLINICAL EXPERIENCE
Michael Patkin & George Tolstoshev
The Whyalla Hospital, South Australia
Presented at the Fourth Australian Workshop on Gastric Surgery for Obesity, Bright, Victoria, September 1983.