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Advances in Audiology, Vol. 4, Middle Ear Implant: Implantable Hearing Aids
185
International Journal of Pediatric Otorhinolaryngologv, 17 (1989) 185-188 Elsevier
Book Reviews Advances in Audiology, Vol. 4, Middle Ear Implant: Implantable Hearing Aids. J.I. Suzuki (Ed.), S. Karger, Basel, 1988, ISBN 3-80.55-4620-3,
1 I7 Illustr., 19 Tables.
The book Middle Ear Implant: Implantable Hearing Aids is a coordinated collection of papers, primarily from one group concerning their development of the middle ear implant (MEI). The presentation of the work from the group is a model of cooperation between industry, government, and science in the rational development of a medical prosthesis. The first two chapters are authored by Dr. Suzuki entitled Early Studies in History Development of the Middle Ear Implant in Japan and Principle Construction and Indication of the Middle Ear Implants, and are commendable for any group undertaking a major biomedical technological advance. The advantages and limitations of ME1 are well defined. Essentially, at the present time the ME1 can be used in adult patients who have bone conduction threshold pure tone average between 20 to 40 dB. The device described in this work consists of a ceramic vibrator, which is attached either to the footplate or the head of the stapes. They have developed two methods of insertion, depending upon the condition of the middle ear and the mastoid. The volume also includes chapters by others who, have worked in this area, including Goode and Tjellstrom. The latter’s chapter was too general, and one would have wished for a more detailed presentation of the device developed by Tjellstrom et al. as compared to the device which had been developed by Suzuki et al. This would have been an addition to the volume. The advantages of the MEI, when compared to the traditional in the ear and bone conduction hearing aid, are described throughout the book. They include a widened frequency response, decreased distortion, and decreased feedback. The qualitative assessment of the MEI hearing device appears to confirm these stated objectives. Where the information is available, all the patients state, their perception of hearing is much clearer with the middle ear implantable device, than with the hearing aid. However, as can be seen in Table III, on page 39, there is no significant difference in speech discrimination. Some of the patients had very good speech discrimination, so one is working with a “ceiling effect” this is an area which should be explored further. In Chapter 51 by Dr. Ohno entitled Structure and Performance of the Main Components the statement is made that the solution chosen was to implant the vibrator at the stapes head. However, there is no data given concerning the findings that they imply have been found. It would have been good to have had at least one table or graft showing the quantitative or qualitative data, which underlies this 0165-5876/89/$03.50
0 1989 Elsevier Science Publishers
B.V. (Biomedical
Division)
186
assumption. A major draw back of the device is its life expectancy of the battery. The actual life expectancy of the entire unit, which is limited by approximately two years, is limited by the energy source as described in Ikeda’s chapter entitled Energy Source for the Middle Ear Implant. The final table (Table V) shows that both the primary and secondary battery cell life are considered to only have life expectancy of over two years. That would imply clinically that the battery would have to be changed within two years. This then would necessitate another operative procedure to change the batteries for those middle ear implants which were totally implanted. Because of this problem and also decreased dynamic range of a totally implanted ME1 the group have decided to place their emphasis on what is termed partially implanted ME1 (PMEI). This device has an induction coil driven by an external device, which is held on the skin over the implanted device, and through electromagnetic induction signal, is transmitted across the skin to the vibrator. There are a number of advantages listed for the PMEI. First is that the battery can be changed without a surgical exploration. Additionally, new controls and new technology can be instituted through the external device, without changing the internal device. The major disadvantage is that of the cosmetic appearance of having to wear an external device. The study group has started out with a definitive plan. They used a small number of well studied and well controlled patients, so that the data which has been presented is most useful. In many ways, the way in which this group of investigators has gone about developing their middle ear prosthesis, should serve as a model for any group, which is in the process of developing either the middle ear, or any area of prosthesis. This is best evidenced in the report on the patient results in the chapters, whose chief authors are N. Yanagihara et al. entitled Intraoperative Assessment of Vibrator-Induced Hearing, S. Hiki et al., Audiological Evaluation of the Middle Ear Implant, N. Yanagihari et al., Efficacy of the Partially Implantable Middle Ear Implant in Middle and Inner Ear Disorders, and the final chapter whose senior author is J.I. Suzuki, entitled Implantation of the Partially Implantable Middle Ear Implant in the Indication. The patients have been well worked up and there is good detail given in the text. The data from Figures 5-10 on pages 155-157 reveal some problems. Four out of 6 patients showed what appeared to be a large increase in threshold at some frequencies, of which some showed an increase in bone conduction threshold. There was no data available on one, and the sixth patient showed a modest improvement in bone conduction. On page 165 and 166, in Figures 4 and 5, two other patients are shown. One of them showed a decrease in bone conduction of the high frequencies and in the other, essentially no change was shown. This is not commented on in the text and should be explained. Overall, this is an extremely instructive and important monograph, which should be thoroughly read and studied by all those in otorhinolaryngology who are working on any type of electric-mechanical prosthesis, be it for the ear, larynx, or the facial nerve, etc. This group has shown the way in which there can be rational development of an idea, carry it through animal experimentation, develop the concept and the material and then set up a rational protocol with goals and objectives, and
187
instruments for measurement. The group is to be highly complimented on the techniques and development of their middle ear implant, their candid, accurate, and total reporting of data and in their regard of the ethical problems of human experimentation. R.J. Ruben,
Microsurgery
Georg Thieme 440.
Bronx, NY, U.S.A.
of the skull base. Ugo Fisch and Douglas Mattox
Verlag, Stuttgart
- New York, 1988, 669 pp. 1310 illustr., Price DA4
Microsurgery of the temporal bone entered a new era when the concepts of functional ear surgery were introduced in the 1950s. During the following decades operating microscopes came into routine use and with the new possibilities for diagnosis offered by radiological imaging techniques significant advances were made in surgical methods for removal of pathology until then deemed inoperable. One of the pioneers in this field was Ugo Fisch, Head of the Zurich clinic, which has long been one of the foremost teaching centers for temporal bone surgery. It is therefore with great pleasure one starts the perusal of the book ‘Microsurgery of the Skull Base’ in which the experience from several decades of surgery at this clinic has been recorded. The book comprises 669 pages and is printed on high-quality paper, making the radiographic reproductions easy to interpret. The quality of the intraoperative photographs is superb and the pictures are clearly marked for orientation. The book is divided into 10 chapters; 8 chapters are devoted to surgery and 2 to anesthesia and interventional radiography of the temporal bone. The operative procedures are described step by step from incision to wound closure. This is done with the help of schematic drawings which concentrate on essentials but nevertheless give a clear picture of the chronological order of the steps. The first chapter describes subtotal petrosectomy, which essentially follows the treatment policies for apicitis, established during the preantibiotic era. The new features include mastoid obliteration and closure of the external meatus. The applications include repair and rerouting of the facial nerve for a variety of conditions but especially for removal of supralabyrinthine cholesteatoma or temporal bone tumors with sacrifice of the labyrinth. This chapter is particularly valuable to the ear surgeon who may occasionally be faced with chronic inflammatory cases in which more demanding techniques must be mastered. For removal of acoustic neuromas less than 2.5 cm in diameter Fisch has switched from a translabyrinthine to a transotic approach in which he follows the principles of subtotal petrosectomy. I can well see the advantages this approach has in giving a direct view of the anterior part of the meatus, which may be difficult to
International Journal of Pediatric Otorhinolaryngologv, 17 (1989) 185-188 Elsevier
Book Reviews Advances in Audiology, Vol. 4, Middle Ear Implant: Implantable Hearing Aids. J.I. Suzuki (Ed.), S. Karger, Basel, 1988, ISBN 3-80.55-4620-3,
1 I7 Illustr., 19 Tables.
The book Middle Ear Implant: Implantable Hearing Aids is a coordinated collection of papers, primarily from one group concerning their development of the middle ear implant (MEI). The presentation of the work from the group is a model of cooperation between industry, government, and science in the rational development of a medical prosthesis. The first two chapters are authored by Dr. Suzuki entitled Early Studies in History Development of the Middle Ear Implant in Japan and Principle Construction and Indication of the Middle Ear Implants, and are commendable for any group undertaking a major biomedical technological advance. The advantages and limitations of ME1 are well defined. Essentially, at the present time the ME1 can be used in adult patients who have bone conduction threshold pure tone average between 20 to 40 dB. The device described in this work consists of a ceramic vibrator, which is attached either to the footplate or the head of the stapes. They have developed two methods of insertion, depending upon the condition of the middle ear and the mastoid. The volume also includes chapters by others who, have worked in this area, including Goode and Tjellstrom. The latter’s chapter was too general, and one would have wished for a more detailed presentation of the device developed by Tjellstrom et al. as compared to the device which had been developed by Suzuki et al. This would have been an addition to the volume. The advantages of the MEI, when compared to the traditional in the ear and bone conduction hearing aid, are described throughout the book. They include a widened frequency response, decreased distortion, and decreased feedback. The qualitative assessment of the MEI hearing device appears to confirm these stated objectives. Where the information is available, all the patients state, their perception of hearing is much clearer with the middle ear implantable device, than with the hearing aid. However, as can be seen in Table III, on page 39, there is no significant difference in speech discrimination. Some of the patients had very good speech discrimination, so one is working with a “ceiling effect” this is an area which should be explored further. In Chapter 51 by Dr. Ohno entitled Structure and Performance of the Main Components the statement is made that the solution chosen was to implant the vibrator at the stapes head. However, there is no data given concerning the findings that they imply have been found. It would have been good to have had at least one table or graft showing the quantitative or qualitative data, which underlies this 0165-5876/89/$03.50
0 1989 Elsevier Science Publishers
B.V. (Biomedical
Division)
186
assumption. A major draw back of the device is its life expectancy of the battery. The actual life expectancy of the entire unit, which is limited by approximately two years, is limited by the energy source as described in Ikeda’s chapter entitled Energy Source for the Middle Ear Implant. The final table (Table V) shows that both the primary and secondary battery cell life are considered to only have life expectancy of over two years. That would imply clinically that the battery would have to be changed within two years. This then would necessitate another operative procedure to change the batteries for those middle ear implants which were totally implanted. Because of this problem and also decreased dynamic range of a totally implanted ME1 the group have decided to place their emphasis on what is termed partially implanted ME1 (PMEI). This device has an induction coil driven by an external device, which is held on the skin over the implanted device, and through electromagnetic induction signal, is transmitted across the skin to the vibrator. There are a number of advantages listed for the PMEI. First is that the battery can be changed without a surgical exploration. Additionally, new controls and new technology can be instituted through the external device, without changing the internal device. The major disadvantage is that of the cosmetic appearance of having to wear an external device. The study group has started out with a definitive plan. They used a small number of well studied and well controlled patients, so that the data which has been presented is most useful. In many ways, the way in which this group of investigators has gone about developing their middle ear prosthesis, should serve as a model for any group, which is in the process of developing either the middle ear, or any area of prosthesis. This is best evidenced in the report on the patient results in the chapters, whose chief authors are N. Yanagihara et al. entitled Intraoperative Assessment of Vibrator-Induced Hearing, S. Hiki et al., Audiological Evaluation of the Middle Ear Implant, N. Yanagihari et al., Efficacy of the Partially Implantable Middle Ear Implant in Middle and Inner Ear Disorders, and the final chapter whose senior author is J.I. Suzuki, entitled Implantation of the Partially Implantable Middle Ear Implant in the Indication. The patients have been well worked up and there is good detail given in the text. The data from Figures 5-10 on pages 155-157 reveal some problems. Four out of 6 patients showed what appeared to be a large increase in threshold at some frequencies, of which some showed an increase in bone conduction threshold. There was no data available on one, and the sixth patient showed a modest improvement in bone conduction. On page 165 and 166, in Figures 4 and 5, two other patients are shown. One of them showed a decrease in bone conduction of the high frequencies and in the other, essentially no change was shown. This is not commented on in the text and should be explained. Overall, this is an extremely instructive and important monograph, which should be thoroughly read and studied by all those in otorhinolaryngology who are working on any type of electric-mechanical prosthesis, be it for the ear, larynx, or the facial nerve, etc. This group has shown the way in which there can be rational development of an idea, carry it through animal experimentation, develop the concept and the material and then set up a rational protocol with goals and objectives, and
187
instruments for measurement. The group is to be highly complimented on the techniques and development of their middle ear implant, their candid, accurate, and total reporting of data and in their regard of the ethical problems of human experimentation. R.J. Ruben,
Microsurgery
Georg Thieme 440.
Bronx, NY, U.S.A.
of the skull base. Ugo Fisch and Douglas Mattox
Verlag, Stuttgart
- New York, 1988, 669 pp. 1310 illustr., Price DA4
Microsurgery of the temporal bone entered a new era when the concepts of functional ear surgery were introduced in the 1950s. During the following decades operating microscopes came into routine use and with the new possibilities for diagnosis offered by radiological imaging techniques significant advances were made in surgical methods for removal of pathology until then deemed inoperable. One of the pioneers in this field was Ugo Fisch, Head of the Zurich clinic, which has long been one of the foremost teaching centers for temporal bone surgery. It is therefore with great pleasure one starts the perusal of the book ‘Microsurgery of the Skull Base’ in which the experience from several decades of surgery at this clinic has been recorded. The book comprises 669 pages and is printed on high-quality paper, making the radiographic reproductions easy to interpret. The quality of the intraoperative photographs is superb and the pictures are clearly marked for orientation. The book is divided into 10 chapters; 8 chapters are devoted to surgery and 2 to anesthesia and interventional radiography of the temporal bone. The operative procedures are described step by step from incision to wound closure. This is done with the help of schematic drawings which concentrate on essentials but nevertheless give a clear picture of the chronological order of the steps. The first chapter describes subtotal petrosectomy, which essentially follows the treatment policies for apicitis, established during the preantibiotic era. The new features include mastoid obliteration and closure of the external meatus. The applications include repair and rerouting of the facial nerve for a variety of conditions but especially for removal of supralabyrinthine cholesteatoma or temporal bone tumors with sacrifice of the labyrinth. This chapter is particularly valuable to the ear surgeon who may occasionally be faced with chronic inflammatory cases in which more demanding techniques must be mastered. For removal of acoustic neuromas less than 2.5 cm in diameter Fisch has switched from a translabyrinthine to a transotic approach in which he follows the principles of subtotal petrosectomy. I can well see the advantages this approach has in giving a direct view of the anterior part of the meatus, which may be difficult to