The indications for stapedectomy By VALENTINE HAMMOND (London, England) the initial work of Shea (1958) many stapedectomies were performed and in the 1960s several large series were published. There was widespread agreement that a better than 90 per cent success rate could be expected with a risk to the hearing of 1 per cent or less. It was generally I recognized that although the long-term results might be unpredictable, surgery to the second ear was reasonable if the operation on the first side , had been a success. It is difficult to obtain accurate figures for long-term results because of the low rate of follow-up in most series (Kos, 1969; House, 1969; McGhee, 1969; Hough, 1969). With the exception of Hough they record a remarkably low follow-up rate but all show a definite fall-off in results with time (Tables I, II, III, IV). AFTER
TABLE I.
TABLE II.
HOWARD HOUSE (WIRE AND GEL FOAM)
MCGEE (FAT AND WIRE)
4 months 5 years
9i% 75%
Follow up
35%
Gain>25 db 1 year 6 years
89-5% 83-8%
Follow-up
55%
TABLE III.
TABLE IV.
KOS (VEIN PLUG)
HOUGH (PARTIAL STAPEDECTOMY)
1 year 5 years
83% 75%
6 months 5—7 years
Follow up
30%
20 Cases all followed up
95% 85%
Stapedectomy is the operation of choice for the treatment of otosclerosis, and the majority of patients suffering from otosclerosis can benefit from it. This does not mean that surgery should be recommended for all cases. With few exceptions any patient who will benefit from surgery will also benefit from a hearing aid. The advisability of stapedectomy can be considered under the following headings: 23
Valentine Hammond 1. Age
It is unwise to perform stapes surgery in a young child with the inherent risks of middle ear infection or Eustachian tube dysfunction. These considerations should rule out stapes surgery in those under 12. Rapid progress of the otosclerotic process is usually most marked in the patient under the age of 20. This group tends to respond poorly to surgery and has a distinctly higher incidence of re-closure of the oval window. The uncertainty of the very long-term results of surgery would seem to be an added argument against operation under the age of 20. Old age does not appear to be a contra-indication. Fears are voiced that vertigo might be a greater problem in the elderly but in practice this does not appear to be so. Hearing results in the over 60s are comparable with those in other age groups. I personally find no increased incidence of sensori-neural loss in the over 60s, and Sellick (1975) in his computer studies found that the results in the over 60s are if anything rather better than those in other age groups. On the other hand, Owens et al. (1972) assessing speech discrimination loss after stapedectomy regarded the over 60s as a high risk group and Sirala (1969) reviewing 1,014 operations found the 31 to 60 age group achieved the best results. . Schuknecht (1971) delays surgery until the age of 20 but does not set any upper age limit. However, as he says, there is little point in encouraging an elderly patient to have an operation if he has already become well-adjusted to a hearing aid over,the years. 2. Occupation
Undoubtedly the stapedectomized ear is at greater risk from sudden changes in barometric pressure than the normal. Fistulae following stapedectomy have been reported after flying in commercial aircraft and even after driving in the mountains. Animal experiments (Hanna and Collins, 1974) have not proved very rewarding in assessing the degree of risk involved. In humans the risk is small, and it would seem over-cautious to advise patients never to fly, even as passengers. Where the patient's occupation involves repeated exposure to changes in barometric pressure the position is different. Not only is the potential risk to hearing greater, but associated vertigo could result in a serious loss of control. Improvements in stapedectomy technique are reducing the incidence of fistulae in general and perhaps a technique will evolve which will be virtually impervious to major variations in barometric pressure. This has not been achieved to date, and for the time being I would submit that it is unreasonable to recommend surgery for any patient whose occupation involves the risk of sudden pressure change. Professional aircrew, divers, and submariners would all come within this category. The possible risks must also be made clear to all patients as a change in 24
The indications for stapedectomy occupation may occur after surgery, perhaps after the patient has ceased to attend hospital for follow-up. Hobbies too, can bring increased risk. The amateur pilot flying a light aircraft is often subjected to sudden variations in pressure. 'Scuba' diving is an increasingly popular pastime and stapedectomy should certainly preclude participation in this sport. Although long-term vertigo is not a common post-operative symptom, some patients complain of persistent unsteadiness or positional vertigo. Stroud (1963) in a study of 100 cases of stapedectomy found evidence of impaired vestibular function in 22 per cent. Fussing and Peiterson (1965) studying 130 cases found reduced vestibular function in 8 per cent at 6 months and in 4 per cent at a year. Spector (1973) in an electronystagmogram study of 62 cases following stapedectomy found that 13 per cent of the cases with normal pre-operative calorics showed impaired function post-operatively. Even when caloric abnormalities are associated with subjective symptoms the majority of patients will become symptom-free in time. However, the possible implication for patients engaged in occupations requiring a good sense of balance cannot be overlooked. Noise
Some patients complain of persistent hyperacusis following stapes surgery and may therefore find their working conditions more trying than before surgery. There is no evidence, however, that the ear upon which a stapedectomy has been performed is more prone to acoustic trauma than the normal ear. Ferris (1965, 1967) in his studies of the temporary effect of industrial noise on stapedectomized ears was unable to demonstrate any significant difference as compared with the controls. I do not regard working in a noisy industrial environment as a definite contra-indication to surgery. However, in view of the problem of persisting or increased high tone loss after stapedectomy we should bear in mind that prolonged exposure to loud noise could carry some risk of further impairment in those individuals who already have a loss of discrimination. 3. Anaesthetic risks
Any consideration of the indications for stapes surgery involves evaluating the risk to the patient of the operation and anaesthesia. In this country the majority of cases have their operations under general anaesthesia, which is more pleasant for the patient and less taxing for the surgeon. The risks are very small, and few cases would be regarded as unfit for anaesthesia. A few cases of cardiac arrest have been reported during stapes surgery. These have usually been attributed to the administration of too large a dose of adrenalin as a local infiltration when halothane is being used as the anaesthetic agent. The use of adrenalin of no greater strength than 1 in 200,000 for infiltration would seem to overcome this. In some centres hypotensive techniques are used routinely. In competent 25
Valentine Hammond hands this would seem to be a safe technique although I would dispute its necessity. A reasonably bloodless field can be obtained in the majority of cases with a combination of good general anaesthesia and elevation of the head with the addition of adrenalin as both an infiltration and a topical application. I feel that the wide-spread routine use of hypotensive techniques adds an additional potential risk to what is after all a purely elective procedure. Bleeding can be a nuisance and cause delays, but it does not seem to present a hazard as far as the ultimate result of surgery is concerned. It is widely accepted that small quantities of blood entering the vestibule do not impair the hearing result. 4. The second ear
There is now a growing body of opinion in this country that surgery for the second ear is rarely if ever indicated. This opinion has evolved as we have become increasingly aware of the occurrence of late sensori-neural hearing loss after stapes surgery. Ludman and Grant (1973) in their study of 139 patients of the King's College Hospital series who had undergone bilateral operations found the incidence of sensori-neural hearing loss to be 3 per cent in one year but in those still available for late follow-up the incidence was 12 per cent. Admittedly this series contained a number of cases who had had multiple operations. However, of particular significance was his finding that more sensori-neural losses arose late in the series than early, in one case 9 years after the original surgery. Other authors (Dawes and Curry, 1969; Munro, 1969) have produced similar findings. On the other hand Sooy (1973) studied a group of 76 successful stapedectomies at 4 months and eight years after operation and found no significant deterioration in the hearing for this period. McGee (1969) compared the average bone conduction level in the speech frequencies at 6 years with the preoperative bone conduction and found a loss of 11-25 db m 12 • 4 per cent but none had lost more than 25 db. House et al. (1969) compared the bone conduction at four months and five years in 107 cases and 85 per cent remained within 10 db of the four month level. Thirteen per cent shifted 11-20 db and two cases shifted 21-30 db. Apart from severe loss, some deterioration occurs but it is extremely difficult to assess the true incidence of long-term hearing loss as most large series have a poor follow-up rate. Furthermore any sensorineural loss must be related to the effects of presbyacusis and the effect of otosclerosis itself. In view of the evidence available at the moment I would not advocate surgery to the second ear at any period after the successful treatment of the first. 5. Revision operations
Revision surgery is indicated in two main groups of cases, (a) Perilymph fistula When a perilymph fistula is suspected early exploration is indicated. 26
The indications for stapedectomy Although removal of the prosthesis and re-grafting of the oval window carries a risk of further hearing loss, the risks of waiting are far greater. When a severe sensori-neural hearing loss has already occurred there is little hope of hearing being regained but the ear should be explored so that any possible fistula can be sealed off. This eliminates a potentially dangerous track for infection and will often relieve associated vertigo or tinnitus. In a study of the long-term results of operating on perilymph ristulae Althaus (1973) reported that where good hearing is still present closure of the fistula carried a 34 per cent chance of improving the hearing and a 30 per cent chance of maintaining the hearing. In 27 per cent the hearing was made worse as a result of operation. In addition the vertigo was relieved in 47 per cent and improved in 29 per cent of cases. He confirmed that the prognosis for the hearing was worse in those cases that also had vertigo. The end-results of perilymph fistula are probably less favourable than these figures indicate. Many cases in the past must have been overlooked and no doubt a few still are. Perilymph fistula is a major problem, the results of treatment are far from satisfactory, and the answer lies in prevention rather than cure. The choice of prosthesis and sealing material are the vital factors here although no method is entirely without risk. Shea (1971) reported no fistulas at all using a teflon piston and vein graft technique in 1,943 cases treated between 1965 and 1970. However, Marquet et at. (1972) reported 1,550 cases with no fistuals when using a teflon piston with a small hole in the footplate and no graft material. From the literature it would seem that the best choice lies between: (1) Vein grafting with a plastic prosthesis of the Shea type. (2) Vein or fat grafting with a wire prosthesis. Here the importance of careful centring of the wire in the oval window is emphasized. (3) A snugly fitting piston of carefully measured length. (b) Recurrence of the conductive deafness For recurrence of conductive hearing loss exploration is indicated if the patient wishes it, unlike the case of suspected fistula when operation must be urged upon the patient. With a recurrent conductive loss it must be made clear to the patient that there is a greater risk of damaging the residual hearing than was involved in the original procedure (Shea, 1971; Ludman, et al., 1973; Schuknecht, 1971; Shah, 1974; Dawes and Curry (1974). The overall success rate in closing the air-bone gap to within 10 db lies between 40 and 50 per cent in revision operations. Where the cause of the deafness proves to be a simple displacement of the prosthesis results of replacement are usually good. When revision involves re-opening or re-drilling of the oval window the incidence of sensori-neural hearing loss increases. The most prudent policy in these cases is to leave the oval window alone so that no further damage can be done and if necessary a hearing aid can be fitted with good effect. Whenever stapedectomy is 27
Valentine Hammond indicated every technical effort must be made to ensure that the first operation is the last. The use of tissue grafting and the fitting of a suitable prosthesis of correct length and accurately centred should contribute to a reduced need for multiple procedures. 6. Unilateral otosclerosis
In my view this is rarely an indication for surgery. Only in exceptional cases is unilateral deafness a serious disability in relation to an individual's occupation. It is often a social nuisance but I do not think that this can be seriously regarded as a good reason for operation. Stapedectomy has been advocated for patients who wished to gain entry to professions where good binaural hearing is required as a condition of entry. Certainly a successful stapedectomy can fulfil these requirements with little or nothing to indicate that anything has been done. I regard this as a potentially dangerous deception particularly in relation to candidates for the armed services or civil airlines. A future policy for stapes surgery
Following the introduction of stapedectomy a large number of operations were performed by relatively few surgeons. There'was a considerable reservoir of clinical material and a limited number of centres where the necessary equipment and expertise were available. Now the number of cases presented annually to any one clinic has stabilized and represents the newly developing cases in the population. Training in microsurgery has been widespread and there can now be few E.N.T. departments in the United Kingdom where stapes surgery is not performed. Inevitably this has resulted in more surgeons treating fewer cases (Fig. i). Moreover, a conservative attitude towards the indications for surgery, particularly in regard to the second ear and revision operations, is leading to a further reduction in the numbers coming to operation. The development of the ear-level hearing aid over the last 20 years has no doubt been an additional factor in encouraging some patients to adopt this alternative to surgery. As the Health Service is now issuing an ear-level aid we may well see a further decline in the number of cases requiring surgical treatment. The implications of these factors are fairly obvious. In stapedectomy the best' results are obtained by the more experienced and skilled surgeons. It is true that an uncomplicated stapedectomy can be a reasonably simple procedure. Unfortunately not all cases are like this. Although the concept of increasing specialization within E.N.T. has never been very popular here, I think the time is coming when stapedectomy as well as other forms of microsurgery of the ear will have to be concentrated in a small number of specialized centres. Only thus can we hope to ensure a continuing high standard of otological surgery in this country. Centralization would not only provide better facilities at a time of decreasing resources; 28
The indications for stapedectomy 120 110 -
YEAR
'62
'63
'64
'65
'66
'67
'68
'69
'70
'71
ANNUAL FIGURES FOR STAPEDECTOMY IN ST. THOMAS' HOSPITAL. FIG. I.
it would also ensure an adequate flow of case material to allow some surgeons at least to gain sufficient expertise. The potential for research would be far greater in such centres and it would be possible to provide more comprehensive training for post-graduates who show an aptitude for this type of work. REFERENCES ALTHAUS, S. R. (1973) Laryngoscope, 83, 1502. DAWES, J. D. K., and CURRY, A. R. (1974) Journal of Laryngology and Otology, 88, 213.
DAWES, J. D. K., and CURRY, A. R. (1969) Journal of Laryngology and Otology, 89, 420. FERRIS, K. (1967) Journal of Laryngology and Otology, 81, 613. FERRIS, K. (1965) Journal of Laryngology and Otology, 79, 881. FUSSING, T., and PEITERSEN, E. (1965) Ada Oto-Laryngologica, 60, 265.
HANNA, H. H., and COLLINS, F. G. (1974) Aerospace Medicine, 45, 548. HOUGH, J. V. (1969) Archives of Otolaryngology, 89, 414. HOUSE, H. P., and GREENFIELD, E. C. (1969) Archives of Otolaryngology, 89, 420. Kos, C. M. (1969) Archives of Otolaryngology, 89, 422. LUDMAN, H., and GRANT, H. (1973) Journal of Laryngology and Otology, 87, 833. 29
Valentine Hammond MCGEE, T. M. (1969) Archives of Otolaryngology, 89, 423. MARQUET, J., CRETEN, W. L., and VAN CAMP, K. J. (1972) Ada Oto-Laryngologica,
74, 406. MUNRO, I. P. (1969) Journal of Laryngology and Otology, 83, 655. OWENS, E., SOOY, F. A., and EGGER, D. T. (1972) Annals of Otology, Rhinology and
Laryngology, 81, 157. SCHUKNECHT, H. F. (1971) Stapedectomy, Chapter 6, p. 50, Little Brown & Co., Boston. SELLICK, R. J. (1975) Personal Communication. SHAH, X. (1974) Journal of Laryngology and Otology, 88, 207. SHEA, J. J. J R . (1971) Transactions of the American Academy of Ophthalmology and Otolaryngology, 75, 31. SHEA, J. J. J R . (1958) Annals of Otology, Rhinology and Laryngology, 67, 932. SIEBENMANN, F. (1900) International Medical Congress, Section of Otology, 13, 11. SIIRALA, U., LUMIO, J. S., and JAUHIAINEN, T. (1969) Archives of Otolaryngology, 90, 129.
SOOY, F. A., OWEXS, E., and NEUFELD, E. S. (1973) Annals of Otology, Rhinology
and Laryngology, 82,13. SPECTOR, M. (1973) Annals of Otology, Rhinology and Laryngology, 82, 374. STROUD, M. H. (1963) Laryngoscope, 73, 474. Department of Otolaryngology, St. Thomas's Hospital, Lambeth Palace Road, London, SEi7EH.
(
3°
TABLE I.
TABLE II.
HOWARD HOUSE (WIRE AND GEL FOAM)
MCGEE (FAT AND WIRE)
4 months 5 years
9i% 75%
Follow up
35%
Gain>25 db 1 year 6 years
89-5% 83-8%
Follow-up
55%
TABLE III.
TABLE IV.
KOS (VEIN PLUG)
HOUGH (PARTIAL STAPEDECTOMY)
1 year 5 years
83% 75%
6 months 5—7 years
Follow up
30%
20 Cases all followed up
95% 85%
Stapedectomy is the operation of choice for the treatment of otosclerosis, and the majority of patients suffering from otosclerosis can benefit from it. This does not mean that surgery should be recommended for all cases. With few exceptions any patient who will benefit from surgery will also benefit from a hearing aid. The advisability of stapedectomy can be considered under the following headings: 23
Valentine Hammond 1. Age
It is unwise to perform stapes surgery in a young child with the inherent risks of middle ear infection or Eustachian tube dysfunction. These considerations should rule out stapes surgery in those under 12. Rapid progress of the otosclerotic process is usually most marked in the patient under the age of 20. This group tends to respond poorly to surgery and has a distinctly higher incidence of re-closure of the oval window. The uncertainty of the very long-term results of surgery would seem to be an added argument against operation under the age of 20. Old age does not appear to be a contra-indication. Fears are voiced that vertigo might be a greater problem in the elderly but in practice this does not appear to be so. Hearing results in the over 60s are comparable with those in other age groups. I personally find no increased incidence of sensori-neural loss in the over 60s, and Sellick (1975) in his computer studies found that the results in the over 60s are if anything rather better than those in other age groups. On the other hand, Owens et al. (1972) assessing speech discrimination loss after stapedectomy regarded the over 60s as a high risk group and Sirala (1969) reviewing 1,014 operations found the 31 to 60 age group achieved the best results. . Schuknecht (1971) delays surgery until the age of 20 but does not set any upper age limit. However, as he says, there is little point in encouraging an elderly patient to have an operation if he has already become well-adjusted to a hearing aid over,the years. 2. Occupation
Undoubtedly the stapedectomized ear is at greater risk from sudden changes in barometric pressure than the normal. Fistulae following stapedectomy have been reported after flying in commercial aircraft and even after driving in the mountains. Animal experiments (Hanna and Collins, 1974) have not proved very rewarding in assessing the degree of risk involved. In humans the risk is small, and it would seem over-cautious to advise patients never to fly, even as passengers. Where the patient's occupation involves repeated exposure to changes in barometric pressure the position is different. Not only is the potential risk to hearing greater, but associated vertigo could result in a serious loss of control. Improvements in stapedectomy technique are reducing the incidence of fistulae in general and perhaps a technique will evolve which will be virtually impervious to major variations in barometric pressure. This has not been achieved to date, and for the time being I would submit that it is unreasonable to recommend surgery for any patient whose occupation involves the risk of sudden pressure change. Professional aircrew, divers, and submariners would all come within this category. The possible risks must also be made clear to all patients as a change in 24
The indications for stapedectomy occupation may occur after surgery, perhaps after the patient has ceased to attend hospital for follow-up. Hobbies too, can bring increased risk. The amateur pilot flying a light aircraft is often subjected to sudden variations in pressure. 'Scuba' diving is an increasingly popular pastime and stapedectomy should certainly preclude participation in this sport. Although long-term vertigo is not a common post-operative symptom, some patients complain of persistent unsteadiness or positional vertigo. Stroud (1963) in a study of 100 cases of stapedectomy found evidence of impaired vestibular function in 22 per cent. Fussing and Peiterson (1965) studying 130 cases found reduced vestibular function in 8 per cent at 6 months and in 4 per cent at a year. Spector (1973) in an electronystagmogram study of 62 cases following stapedectomy found that 13 per cent of the cases with normal pre-operative calorics showed impaired function post-operatively. Even when caloric abnormalities are associated with subjective symptoms the majority of patients will become symptom-free in time. However, the possible implication for patients engaged in occupations requiring a good sense of balance cannot be overlooked. Noise
Some patients complain of persistent hyperacusis following stapes surgery and may therefore find their working conditions more trying than before surgery. There is no evidence, however, that the ear upon which a stapedectomy has been performed is more prone to acoustic trauma than the normal ear. Ferris (1965, 1967) in his studies of the temporary effect of industrial noise on stapedectomized ears was unable to demonstrate any significant difference as compared with the controls. I do not regard working in a noisy industrial environment as a definite contra-indication to surgery. However, in view of the problem of persisting or increased high tone loss after stapedectomy we should bear in mind that prolonged exposure to loud noise could carry some risk of further impairment in those individuals who already have a loss of discrimination. 3. Anaesthetic risks
Any consideration of the indications for stapes surgery involves evaluating the risk to the patient of the operation and anaesthesia. In this country the majority of cases have their operations under general anaesthesia, which is more pleasant for the patient and less taxing for the surgeon. The risks are very small, and few cases would be regarded as unfit for anaesthesia. A few cases of cardiac arrest have been reported during stapes surgery. These have usually been attributed to the administration of too large a dose of adrenalin as a local infiltration when halothane is being used as the anaesthetic agent. The use of adrenalin of no greater strength than 1 in 200,000 for infiltration would seem to overcome this. In some centres hypotensive techniques are used routinely. In competent 25
Valentine Hammond hands this would seem to be a safe technique although I would dispute its necessity. A reasonably bloodless field can be obtained in the majority of cases with a combination of good general anaesthesia and elevation of the head with the addition of adrenalin as both an infiltration and a topical application. I feel that the wide-spread routine use of hypotensive techniques adds an additional potential risk to what is after all a purely elective procedure. Bleeding can be a nuisance and cause delays, but it does not seem to present a hazard as far as the ultimate result of surgery is concerned. It is widely accepted that small quantities of blood entering the vestibule do not impair the hearing result. 4. The second ear
There is now a growing body of opinion in this country that surgery for the second ear is rarely if ever indicated. This opinion has evolved as we have become increasingly aware of the occurrence of late sensori-neural hearing loss after stapes surgery. Ludman and Grant (1973) in their study of 139 patients of the King's College Hospital series who had undergone bilateral operations found the incidence of sensori-neural hearing loss to be 3 per cent in one year but in those still available for late follow-up the incidence was 12 per cent. Admittedly this series contained a number of cases who had had multiple operations. However, of particular significance was his finding that more sensori-neural losses arose late in the series than early, in one case 9 years after the original surgery. Other authors (Dawes and Curry, 1969; Munro, 1969) have produced similar findings. On the other hand Sooy (1973) studied a group of 76 successful stapedectomies at 4 months and eight years after operation and found no significant deterioration in the hearing for this period. McGee (1969) compared the average bone conduction level in the speech frequencies at 6 years with the preoperative bone conduction and found a loss of 11-25 db m 12 • 4 per cent but none had lost more than 25 db. House et al. (1969) compared the bone conduction at four months and five years in 107 cases and 85 per cent remained within 10 db of the four month level. Thirteen per cent shifted 11-20 db and two cases shifted 21-30 db. Apart from severe loss, some deterioration occurs but it is extremely difficult to assess the true incidence of long-term hearing loss as most large series have a poor follow-up rate. Furthermore any sensorineural loss must be related to the effects of presbyacusis and the effect of otosclerosis itself. In view of the evidence available at the moment I would not advocate surgery to the second ear at any period after the successful treatment of the first. 5. Revision operations
Revision surgery is indicated in two main groups of cases, (a) Perilymph fistula When a perilymph fistula is suspected early exploration is indicated. 26
The indications for stapedectomy Although removal of the prosthesis and re-grafting of the oval window carries a risk of further hearing loss, the risks of waiting are far greater. When a severe sensori-neural hearing loss has already occurred there is little hope of hearing being regained but the ear should be explored so that any possible fistula can be sealed off. This eliminates a potentially dangerous track for infection and will often relieve associated vertigo or tinnitus. In a study of the long-term results of operating on perilymph ristulae Althaus (1973) reported that where good hearing is still present closure of the fistula carried a 34 per cent chance of improving the hearing and a 30 per cent chance of maintaining the hearing. In 27 per cent the hearing was made worse as a result of operation. In addition the vertigo was relieved in 47 per cent and improved in 29 per cent of cases. He confirmed that the prognosis for the hearing was worse in those cases that also had vertigo. The end-results of perilymph fistula are probably less favourable than these figures indicate. Many cases in the past must have been overlooked and no doubt a few still are. Perilymph fistula is a major problem, the results of treatment are far from satisfactory, and the answer lies in prevention rather than cure. The choice of prosthesis and sealing material are the vital factors here although no method is entirely without risk. Shea (1971) reported no fistulas at all using a teflon piston and vein graft technique in 1,943 cases treated between 1965 and 1970. However, Marquet et at. (1972) reported 1,550 cases with no fistuals when using a teflon piston with a small hole in the footplate and no graft material. From the literature it would seem that the best choice lies between: (1) Vein grafting with a plastic prosthesis of the Shea type. (2) Vein or fat grafting with a wire prosthesis. Here the importance of careful centring of the wire in the oval window is emphasized. (3) A snugly fitting piston of carefully measured length. (b) Recurrence of the conductive deafness For recurrence of conductive hearing loss exploration is indicated if the patient wishes it, unlike the case of suspected fistula when operation must be urged upon the patient. With a recurrent conductive loss it must be made clear to the patient that there is a greater risk of damaging the residual hearing than was involved in the original procedure (Shea, 1971; Ludman, et al., 1973; Schuknecht, 1971; Shah, 1974; Dawes and Curry (1974). The overall success rate in closing the air-bone gap to within 10 db lies between 40 and 50 per cent in revision operations. Where the cause of the deafness proves to be a simple displacement of the prosthesis results of replacement are usually good. When revision involves re-opening or re-drilling of the oval window the incidence of sensori-neural hearing loss increases. The most prudent policy in these cases is to leave the oval window alone so that no further damage can be done and if necessary a hearing aid can be fitted with good effect. Whenever stapedectomy is 27
Valentine Hammond indicated every technical effort must be made to ensure that the first operation is the last. The use of tissue grafting and the fitting of a suitable prosthesis of correct length and accurately centred should contribute to a reduced need for multiple procedures. 6. Unilateral otosclerosis
In my view this is rarely an indication for surgery. Only in exceptional cases is unilateral deafness a serious disability in relation to an individual's occupation. It is often a social nuisance but I do not think that this can be seriously regarded as a good reason for operation. Stapedectomy has been advocated for patients who wished to gain entry to professions where good binaural hearing is required as a condition of entry. Certainly a successful stapedectomy can fulfil these requirements with little or nothing to indicate that anything has been done. I regard this as a potentially dangerous deception particularly in relation to candidates for the armed services or civil airlines. A future policy for stapes surgery
Following the introduction of stapedectomy a large number of operations were performed by relatively few surgeons. There'was a considerable reservoir of clinical material and a limited number of centres where the necessary equipment and expertise were available. Now the number of cases presented annually to any one clinic has stabilized and represents the newly developing cases in the population. Training in microsurgery has been widespread and there can now be few E.N.T. departments in the United Kingdom where stapes surgery is not performed. Inevitably this has resulted in more surgeons treating fewer cases (Fig. i). Moreover, a conservative attitude towards the indications for surgery, particularly in regard to the second ear and revision operations, is leading to a further reduction in the numbers coming to operation. The development of the ear-level hearing aid over the last 20 years has no doubt been an additional factor in encouraging some patients to adopt this alternative to surgery. As the Health Service is now issuing an ear-level aid we may well see a further decline in the number of cases requiring surgical treatment. The implications of these factors are fairly obvious. In stapedectomy the best' results are obtained by the more experienced and skilled surgeons. It is true that an uncomplicated stapedectomy can be a reasonably simple procedure. Unfortunately not all cases are like this. Although the concept of increasing specialization within E.N.T. has never been very popular here, I think the time is coming when stapedectomy as well as other forms of microsurgery of the ear will have to be concentrated in a small number of specialized centres. Only thus can we hope to ensure a continuing high standard of otological surgery in this country. Centralization would not only provide better facilities at a time of decreasing resources; 28
The indications for stapedectomy 120 110 -
YEAR
'62
'63
'64
'65
'66
'67
'68
'69
'70
'71
ANNUAL FIGURES FOR STAPEDECTOMY IN ST. THOMAS' HOSPITAL. FIG. I.
it would also ensure an adequate flow of case material to allow some surgeons at least to gain sufficient expertise. The potential for research would be far greater in such centres and it would be possible to provide more comprehensive training for post-graduates who show an aptitude for this type of work. REFERENCES ALTHAUS, S. R. (1973) Laryngoscope, 83, 1502. DAWES, J. D. K., and CURRY, A. R. (1974) Journal of Laryngology and Otology, 88, 213.
DAWES, J. D. K., and CURRY, A. R. (1969) Journal of Laryngology and Otology, 89, 420. FERRIS, K. (1967) Journal of Laryngology and Otology, 81, 613. FERRIS, K. (1965) Journal of Laryngology and Otology, 79, 881. FUSSING, T., and PEITERSEN, E. (1965) Ada Oto-Laryngologica, 60, 265.
HANNA, H. H., and COLLINS, F. G. (1974) Aerospace Medicine, 45, 548. HOUGH, J. V. (1969) Archives of Otolaryngology, 89, 414. HOUSE, H. P., and GREENFIELD, E. C. (1969) Archives of Otolaryngology, 89, 420. Kos, C. M. (1969) Archives of Otolaryngology, 89, 422. LUDMAN, H., and GRANT, H. (1973) Journal of Laryngology and Otology, 87, 833. 29
Valentine Hammond MCGEE, T. M. (1969) Archives of Otolaryngology, 89, 423. MARQUET, J., CRETEN, W. L., and VAN CAMP, K. J. (1972) Ada Oto-Laryngologica,
74, 406. MUNRO, I. P. (1969) Journal of Laryngology and Otology, 83, 655. OWENS, E., SOOY, F. A., and EGGER, D. T. (1972) Annals of Otology, Rhinology and
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