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Plastics in Medicine and Surgery
That the IFMBE and IOMP should collaborate in respect of overlapping subjects is agreed but is this large combined meeting every three years the only way? The real question is ‘Are large conferences of any value?’ In my view - not much. I rarely come away from a conference having learnt something specific. This usually comes from reading and doing. What I hope to get from conferences is a stimulation from other people’s ideas and attitudes which may change my own approach. This requires a totally different concept in the organisation of a conference with greater emphasis on detailed discussion. It seems to be accepted, though never proven, that delegates need to present a paper in order to obtain financial support. This leads to a situation where most delegates have to speak, irrespective of whether they have anything of consequence to say, so that the time available for the presentation and discussion of each paper is tmnecessanly restricted. At Jerusalem about 600 papers were allowed for, including poster sessions necessitating six or seven parallel sessions.
If grant authorities and administrators really do insist upon the presentation of a paper, I hope they will look more closely upon the adverse effect this has upon the quality of conferences. They should be supporting delegates for the benefit they might bring back to their units, not for the questionable value of their necessarily brief communications to other delegates. Perhaps they should consider providing funds to delegates who wish to listen, leaving conference organisers to meet the expenses of a limited number of selected speakers. It is perhaps unfair to use this particular conference as a basis for attacking a system as, within the constraints set by the system, it was quite well organised. The IFMBE and IOMP were merely following an established procedure, but surely their objective is the effective dissemination of information in their subjects. Together, they should be able to modify this procedure. I hope they will try,
W.J.
Perkins
PLASTICS IN MEDICINE AND SURGERY Twente
Universityof
Technology
Enschede in the Netherlands
The third conference to be organized by the Plastic and Rubber Institute on the theme Plastics in Medicine and Surgery was attended by approximately 160 delegates from 16 countries attended the meeting, testifying to the topicality of this subject. As usual with any conference, there were some good points and some not-so-good points about the meeting and many of the remarks I made in the report on the Keele biomaterials conference (Vol 1, No. 1, ~67) are equally applicable here. The primary raison d’etre of an international conference is the co-existence of delegates from different centres within one location, to discuss their work. This cannot be achieved if the delegates are scattered about in different hotels and their activities are constrained by coach departure times. It must be said that the fact that this situation existed at Enschede was no fault of the P.R.I. who had their room allocation on the campus decimated at a late stage. However, it did have a significant influence on the meeting. The perennial parallel session problem arose yet again, the solution here being to hold concurrent sessions on the afternoon of one of the two days. Whilst again understanding the reasons for this, I do believe this is the wrong solution and that it is
66
J. Biomed.
Engng.
1980,
Vol.
2, January
June 21-22
better to have greater selectivity in the papers rather than adopt parallel sessions to accommodate more speakers. On the positive side, the preprinting of the papers in a booklet (available from PRI, 11 Hobart Place, London SWlW OHL) is excellent, both in concept and practice. This is perhaps the best answer to the problem of publishing conference proceedings. When authors have to submit abstracts for a conference a year or so before the meeting, and then submit written papers at the time of the conference for a publication that will appear a year, or even years later, there is a considerable time lag between performing the work and seeing it in print. In the method adopted by the PRI the authors can spend the time between submitting the abstract and a few months prior to the conference writing up the paper, in camera-ready format so that all the papers are available at the time of the conference. Such a publication is invaluable, both for prior reading and subsequent reference. A few interleaved clear pages might be an added benefit to supplement with notes, should any author want to update or retract any statements. Forty papers were delivered during the two days of the conference which was opened by the chairman and host, Professor Bantjes. The first paper,
by way of an introduction, was a review of the effects of implant morphology and composition on the soft tissue response, given by Professor D.F. Gibbons of Cleveland, Ohio. He described the tissue response to implant in terms of the ways in which the material reacts with the normal wound healing process. Professor Gibbons put forward the hypothesis that the soft tissue response is dependent upon the way in which two pleuripotential cells, the monocyte and the pericyte, differentiate. The wound without an implant stimulates a basically fibroblastic and macrophage redifferentiation of the monocyte, while epithelial cells derive from pericytes. The presence of a foreign body in the wound increases the number of stimuli controlling redifferentiation and various ways were suggested how this might occur. There is much in the literature on the phenomenology of the tissue response but only in the last few years have we begun to see some hypotheses on mechanisms evolving and this approach is certainly welcome. Following in the same session were two papers on polymer degradation, two on Bioplast, two on polyvinylchloride catheters and one on intraocular lenses. Polymer degradation was first reviewed by Professor J. Leray of Paris and then discussed with specific reference to enzymes by Dr. D.F. Williams of Liverpool. Both papers on Bioplast originated in Hungary and were read by Dr. G. Kerenyi. PVC catheters have been around for a long time, of course, and many discussions have taken place on the problem of plasticizer leaching and toxicity. Dr. G. Hastings from Stoke-on-Trent discussed the possible link between the leaching of the di-Z-ethylhexylphthalate from PVC catheters and necrotizing enterocolitis in neonates and urges that either alternative non-leachable or non-toxic plasticizers should be used or totally different polymers employed instead of PVC. M.S. Biggs, from British Industrial Plastics, described the development of a different plasticizer and speculated on the availability of a low extraction grade of PVC for medical use. Dr. Galin (New York Medical College) provided an informative and well-illustrated review of the use of polymethylmethacrylate for intraocular lenses. Although there are many problems associated with the removal of cataracts and the insertion of intraocular lenses, progress does appear to have been good and high longterm success rates are achieved. The two parallel sessions in the afternoon concemed plastics in orthopaedics, and sterilization and processing of plastics. There seems to be little of interest to report in the area of orthopaedic plastics at the moment. The discussion following a paper by Dr. Tunino of the Netherlands on the use of
low modulus fracture plates showed that there is still a lot of confusion concerning fracture fixation and I remain to be convinced of the need for plates of equivalent modulus to bone. Concerning sterilization, Dr. Ouwerkerk from the Netherlands reviewed the use of gamma irradiation, R. Peterson (Utah, USA), discussed residual ethylene oxide and ethylene chlorohydrin after ethylene oxide sterilization, V. Handles from Denmark concentrated on formaldehyde-steam sterilization and Dr. Meakin, University of Bath discussed the chemical disinfection of contact lenses. A&in-all, these papers provided a useful summary of the status of these various methods. Included in the sterilization and processing session, for some reason, was a paper by Dr. John Autian, University of Tennessee on the screening program that has been developed for the evaluation of biomaterials. The amount of work put into this project and the results obtained are impressive and it is to be hoped that some useful standard protocols will emerge. Also in this session was a paper on the use of antibiotics in silicone rubber catheters for use in hydrocephalus, by Mr. R. Bayston, of Sheffield. Perhaps the most interesting session of the conference was that on blood compatibility, opened by a paper by Dr. Jan Feijen of Enschede on blood foreign surface contact phenomena. This was followed by discussions on protein absorption by Dr. Brash, McMaster University, Canada, and then by Dr. Andrade of Salt Lake City. The work reported in these papers and others in this session contrasts strongly with some of the other work presented at the meeting, for the experimental techniques used are more sophisticated and the scientific content of the work of far greater depth. Much of the work in other areas of biomaterials research seems a little naive in contrast. Comments were made from the floor about the clinical relevance of some of this work but how are we ever going to come to terms with the real situation in patients if we do not understand the fundamental concepts in the first place. Certainly these papers on blood compatibility provided a very interesting and useful session. The conference concluded with a session on miscellaneous topics among which were the immobilization of collagenase on millipore membranes (Dr. R. Sparks, Washington University, USA), elastomers for leaflet heart valves (Dr. W. Hoffacter, F.R. Germany) and controlled drug release (Prof. N. Graham, Strathclyde).
D. Williams
J. Biomed.
Engng.
1980,
Vol.
2, January
67
If grant authorities and administrators really do insist upon the presentation of a paper, I hope they will look more closely upon the adverse effect this has upon the quality of conferences. They should be supporting delegates for the benefit they might bring back to their units, not for the questionable value of their necessarily brief communications to other delegates. Perhaps they should consider providing funds to delegates who wish to listen, leaving conference organisers to meet the expenses of a limited number of selected speakers. It is perhaps unfair to use this particular conference as a basis for attacking a system as, within the constraints set by the system, it was quite well organised. The IFMBE and IOMP were merely following an established procedure, but surely their objective is the effective dissemination of information in their subjects. Together, they should be able to modify this procedure. I hope they will try,
W.J.
Perkins
PLASTICS IN MEDICINE AND SURGERY Twente
Universityof
Technology
Enschede in the Netherlands
The third conference to be organized by the Plastic and Rubber Institute on the theme Plastics in Medicine and Surgery was attended by approximately 160 delegates from 16 countries attended the meeting, testifying to the topicality of this subject. As usual with any conference, there were some good points and some not-so-good points about the meeting and many of the remarks I made in the report on the Keele biomaterials conference (Vol 1, No. 1, ~67) are equally applicable here. The primary raison d’etre of an international conference is the co-existence of delegates from different centres within one location, to discuss their work. This cannot be achieved if the delegates are scattered about in different hotels and their activities are constrained by coach departure times. It must be said that the fact that this situation existed at Enschede was no fault of the P.R.I. who had their room allocation on the campus decimated at a late stage. However, it did have a significant influence on the meeting. The perennial parallel session problem arose yet again, the solution here being to hold concurrent sessions on the afternoon of one of the two days. Whilst again understanding the reasons for this, I do believe this is the wrong solution and that it is
66
J. Biomed.
Engng.
1980,
Vol.
2, January
June 21-22
better to have greater selectivity in the papers rather than adopt parallel sessions to accommodate more speakers. On the positive side, the preprinting of the papers in a booklet (available from PRI, 11 Hobart Place, London SWlW OHL) is excellent, both in concept and practice. This is perhaps the best answer to the problem of publishing conference proceedings. When authors have to submit abstracts for a conference a year or so before the meeting, and then submit written papers at the time of the conference for a publication that will appear a year, or even years later, there is a considerable time lag between performing the work and seeing it in print. In the method adopted by the PRI the authors can spend the time between submitting the abstract and a few months prior to the conference writing up the paper, in camera-ready format so that all the papers are available at the time of the conference. Such a publication is invaluable, both for prior reading and subsequent reference. A few interleaved clear pages might be an added benefit to supplement with notes, should any author want to update or retract any statements. Forty papers were delivered during the two days of the conference which was opened by the chairman and host, Professor Bantjes. The first paper,
by way of an introduction, was a review of the effects of implant morphology and composition on the soft tissue response, given by Professor D.F. Gibbons of Cleveland, Ohio. He described the tissue response to implant in terms of the ways in which the material reacts with the normal wound healing process. Professor Gibbons put forward the hypothesis that the soft tissue response is dependent upon the way in which two pleuripotential cells, the monocyte and the pericyte, differentiate. The wound without an implant stimulates a basically fibroblastic and macrophage redifferentiation of the monocyte, while epithelial cells derive from pericytes. The presence of a foreign body in the wound increases the number of stimuli controlling redifferentiation and various ways were suggested how this might occur. There is much in the literature on the phenomenology of the tissue response but only in the last few years have we begun to see some hypotheses on mechanisms evolving and this approach is certainly welcome. Following in the same session were two papers on polymer degradation, two on Bioplast, two on polyvinylchloride catheters and one on intraocular lenses. Polymer degradation was first reviewed by Professor J. Leray of Paris and then discussed with specific reference to enzymes by Dr. D.F. Williams of Liverpool. Both papers on Bioplast originated in Hungary and were read by Dr. G. Kerenyi. PVC catheters have been around for a long time, of course, and many discussions have taken place on the problem of plasticizer leaching and toxicity. Dr. G. Hastings from Stoke-on-Trent discussed the possible link between the leaching of the di-Z-ethylhexylphthalate from PVC catheters and necrotizing enterocolitis in neonates and urges that either alternative non-leachable or non-toxic plasticizers should be used or totally different polymers employed instead of PVC. M.S. Biggs, from British Industrial Plastics, described the development of a different plasticizer and speculated on the availability of a low extraction grade of PVC for medical use. Dr. Galin (New York Medical College) provided an informative and well-illustrated review of the use of polymethylmethacrylate for intraocular lenses. Although there are many problems associated with the removal of cataracts and the insertion of intraocular lenses, progress does appear to have been good and high longterm success rates are achieved. The two parallel sessions in the afternoon concemed plastics in orthopaedics, and sterilization and processing of plastics. There seems to be little of interest to report in the area of orthopaedic plastics at the moment. The discussion following a paper by Dr. Tunino of the Netherlands on the use of
low modulus fracture plates showed that there is still a lot of confusion concerning fracture fixation and I remain to be convinced of the need for plates of equivalent modulus to bone. Concerning sterilization, Dr. Ouwerkerk from the Netherlands reviewed the use of gamma irradiation, R. Peterson (Utah, USA), discussed residual ethylene oxide and ethylene chlorohydrin after ethylene oxide sterilization, V. Handles from Denmark concentrated on formaldehyde-steam sterilization and Dr. Meakin, University of Bath discussed the chemical disinfection of contact lenses. A&in-all, these papers provided a useful summary of the status of these various methods. Included in the sterilization and processing session, for some reason, was a paper by Dr. John Autian, University of Tennessee on the screening program that has been developed for the evaluation of biomaterials. The amount of work put into this project and the results obtained are impressive and it is to be hoped that some useful standard protocols will emerge. Also in this session was a paper on the use of antibiotics in silicone rubber catheters for use in hydrocephalus, by Mr. R. Bayston, of Sheffield. Perhaps the most interesting session of the conference was that on blood compatibility, opened by a paper by Dr. Jan Feijen of Enschede on blood foreign surface contact phenomena. This was followed by discussions on protein absorption by Dr. Brash, McMaster University, Canada, and then by Dr. Andrade of Salt Lake City. The work reported in these papers and others in this session contrasts strongly with some of the other work presented at the meeting, for the experimental techniques used are more sophisticated and the scientific content of the work of far greater depth. Much of the work in other areas of biomaterials research seems a little naive in contrast. Comments were made from the floor about the clinical relevance of some of this work but how are we ever going to come to terms with the real situation in patients if we do not understand the fundamental concepts in the first place. Certainly these papers on blood compatibility provided a very interesting and useful session. The conference concluded with a session on miscellaneous topics among which were the immobilization of collagenase on millipore membranes (Dr. R. Sparks, Washington University, USA), elastomers for leaflet heart valves (Dr. W. Hoffacter, F.R. Germany) and controlled drug release (Prof. N. Graham, Strathclyde).
D. Williams
J. Biomed.
Engng.
1980,
Vol.
2, January
67