Tympano-nasopharyngeal shunt operation A new method of middle ear ventilation By DR. V. K. MISURYA, (Jhansi (U.P.) India) Summary
THE tympano-nasopharyngeal shunt operation is recommended as a 'substitute' Eustachian tube. An experimental study regarding the efficacy of tympano-nasopharyngeal shunt operation was conducted in two dogs. Finally, four patients with complete tubal stenosis were operated on by this new method within a period of one year, with no postoperative complications. The hearing improved and patients were able to inflate their middle ears. The method is claimed to have the following advantages: permanent ventilation of the middle ear with preservation of an intact drum; the middle-ear pressure can be increased by Valsalva or Politzer manoeuvres; moderate technical difficulties; no risk of postoperative complications; and suitable in children as well as adults. The disadvantages seem to be: drainage not ensured; minor risk of ascending infection. Review of literature
Prior to the concept of tympanoplasty, surgery for the correction of chronic ear disease was connected with control of the infective process. Only when hearing became an important parameter in deciding the result of surgery did it become important to consider Eustachian-tube function. Then the significance of an adequate Eustachian-tube function for maintaining the health and integrity of the tympanic cleft became evident. Zollner (1963) was quick to realize that the Eustachian tube could and must undergo surgical correction in certain cases of chronic ear disease. At the time of surgery he would insert either radio-active material, bougies, silk thread or latterly polythene tube (on suggestion of House, i960) from the middle ear through the Eustachian tube via the nasopharynx to the nasal opening. The inlay was left in place for two weeks to three months depending upon the extent of obstruction. The advantage of tubal tamponade is that it sometimes restores the function of the Eustachian tube, and the ear drum is kept intact. Although Zollner's results were fairly good, he admitted that is was sometimes impossible to reopen the stenosed tube. Less-satisfying results, furthermore, have been reported by others (Wullstein, i960). 189
V. K. Misurya For any of the above methods the Eustachian tube had to have some lumen, however small, for the catheter to be pushed through. Zollner (1963) states that he has been unable to probe or reopen completely obliterated tubes, particularly those where the cartilagenous portion was involved, as in healed tuberculosis. Wullstein (1963) handled total obstruction of the osseous portion of the Eustachian tube during tympanoplasty by blind drilling with a diamond burr and implanted amnion, obtaining a fair result; however, he admitted that he is not likely to try this again in the future. Moreover, the risk of damaging the carotid artery cannot be neglected. House and Miles (1969) have dealt with osseous tubal stenosis by way of a middle fossa approach of the temporal bone, but again the technical difficulty of this method seems to be considerable, with more risk of postoperative complication; and with this approach one cannot deal with stenosis of the cartilagenous Eustachian tube. Armstrong (1954) introduced a simple technique of inserting a plastic tube through a myringotomy opening to provide ventilation and drainage of the middle ear. It is only of temporary value, as sooner or later the plastic tubes will be extruded and the drum will heal. Some devices for fixing the tube have been recommended to obviate this risk, e.g. a small steel wire clip around the handle of malleus (Silverstein, 1906); however, the risk of permanent drum perforation persists. At times, in cases of adhesive otitis media, it is not feasible to introduce a plastic tube through the drum. Moreover, there is no facility for middle-ear inflation, either by a Valsalva manoeuvre or by Politzer inflation. However, in cases where the complete restoration of Eustachian tube function is hoped for, the Armstrong method is of immense value in preventing permanent changes in the middle ear. Lapidot and Kapila (1967) proposed a tympano-oral shunt operation in which Wharton's duct was resected and transplanted to connect the anterior part of the middle ear with the oral cavity. This method was tested only in cadavers. The risk of regurgitation of food through the tube was expected to be minimized by providing a valvular mechanism at the oral end of the tube. The question of viability as well as patency of the transplanted duct, and the fate of the submandibular salivary gland, remained unanswered. This procedure seemed to have more capacity for draining than for ventilating the middle ear. Siirala (1964) introduced a polythene tube under the skin of the meatus from the outside and into the mastoid antrum after mastoidectomy. He provided temporary ventilation of the middle ear by inflation through these polythene tubes. Recently Drettner (1969) has discovered a new method of tympanomaxillary shunt. In this method there is permanent ventilation of the middle ear with preservation of an intact drum; while the middle ear can be inflated by the Valsalva or Politzer manoeuvres. The disadvantages 190
Tympanonasopharyngeal shunt operation seem to be that drainage is not ensured and that there is a minor risk of ascending infection; and of occlusion of the tube. It is unsuitable for children. It is clear from this survey of the presently-known methods that the ideal way of restoring the ventilation of the middle ear is yet to be discovered. The ideal method would fulfil the following requirements: i. permanent ventilation of the middle ear; 2. drainage function; 3. intact tympanic membrane; 4. no permanent discomfort; 5. possibility of overpressure ventilation, e.g. by Valsalva or Politzer manoeuvre; 6. no increased risk of middle-ear infection; 7. negligible risk of surgical complication; 8. minor technical difficulties; 9. that it is applicable in children. The purpose of this paper is to describe a new method—the tympanonasopharyngeal shunt operation—for the management of complete Eustachian-tube stenosis. Material and method
Studies of over fifty temporal bone dissections gave rise to the idea that the anterior end of the canal for the tensor tympani always remains patent, whether the Eustachian tube is stenosed (four bones) or not (forty-six bones). This observation is endorsed by the fact that a few of the muscle fibres of the tensor tympani arise from the cartilagenous Eustachian tube and enter through the medial end of the canal. So it is concluded that the canal for the tensor tympani always remains open at both the ends, even in the presence of tubal stenosis. Secondly, as we know, the tensor tympani canal runs parallel with the whole course of the osseous Eustachian tube and if we pass a probe through the canal of the tensor tympani it will run parallel to the long axis of Eustachian tube (Fig. ia). Theoretically, the Middle Meningeal artery Tensor tympani Eustachean tube
Carotid canal
Probe Tensqrpalati
Cartilage of tube Levator palati
Tegmen
Tympanic bone
Superior constrictor
A. Osseous part
6. Cartilagenous part
FIG. 1. Anatomical relations of Eustachian tube.
probe should appear in the nasopharynx just above the torus tuberius. But in practice it appears in the fossa of Rosenmuller, the reason being that the osseous and cartilagenous parts of the Eustachian tube join at an obtuse angle of 1600 opening outwards (Fig. 2). 191
V. K. Misurya Hence the probe which previously was running along the roof of the osseous Eustachian tube now runs along the postero-medial wall (instead of the roof) of the cartilagenous tube. In this way probing through the canal of the tensor tympani becomes a safe procedure, as the roof and posteromedial aspect of the cartilagenous Eustachian tube are not related to any vital structure. There is no risk of injury to the middle meningeal artery and mandibular nerve as they lie on the anterolateral aspect of the cartilagenous Eustachian tube and remain separated from it by the tensor palati muscle (Fig. ib).
1 Osseus tube 2 Cartilagenous tube 2 3 Canal for tensor tympani 4 Fossa of Rosenmiiller
FIG. 2. Showing obtuse angle (160°) opening outward between bony and cartilagenous part of Eustachian tube.
These above-mentioned facts stimulated the author to evolve a new method—the tympano-nasopharyngeal shunt operation—for tubal stenosis. This newly-devised method has been practised over the Eustachian tubes in ten cadavers. Subsequently the cadavers were dissected to exclude any possibility of damage to the surrounding vital structures. There is no risk of injury to the internal carotid artery as it lies away from the field of operation. This method has proved to be a safe one. The efficacy of the tympano-nasopharyngeal shunt operation was evaluated in artificiallystenosed Eustachian tubes in two dogs. Finally, within one year four cases of complete tubal stenosis in humans have been managed successfully by this new method. Method The tympano-nasopharyngeal shunt operation can be combined with a mastoidectomy or a tympanoplasty. This procedure is undertaken in the following stages: 192
Tympano-nasopharyngeal shunt operation 1. Attico-antrotomy is performed and is extended anteriorly until the tendon of the tensor tympani muscle is visualized. 2. The attachment of the tensor tympani tendon to the neck of the malleus is cut; the anterior half of the bony tensor tympani canal (Fig. 4a(3) is drilled so as to expose the muscle; the tensor tympani muscle is avulsed from its origin, and remaining muscle fibres are curetted from the canal. The posterior half of the canal (Fig. 4a(2) is left intact. 3. Now the silicone tube (Fig. 3), threaded over the introducer (made of stainless steel wire), is introduced through the tensor tympani canal until it comes out into nasopharynx within the fossa of Rosenmiiller (Fig. 2). The introducer during its course slides over the roof of the osseous part and over the postero-medial aspect of the cartilagenous Eustachian tube. Finally, after passing about 38 mm. the introducer is retrieved from the nasopharynx.
FIG. 3. Silicone tube (length 40 mm., inner diameter of wider end 3 mm. and of narrow end^i mm.) with stainless steel wire introducer.
4. The introducer is taken out from the nasopharynx, leaving behind the silicone tube. In this way the silicone tube (approximate dimensions: length 40 mm.; inner diameter of broader end 3 mm., of narrower end 1 mm.) is left in this newly-canalized substitute Eustachian tube (Fig. 5), with its narrower end emerging slightly beyond the pharyngeal opening of the Eustachian tube. 5. The tympanic (broader) end of the silicone tube is anchored to the intact (posterior half) tensor tympani canal, with thin stainless steel wire (Fig. 4e)6. The patency of the tube is checked by irrigation with Ringer's solution which will come out through the nasopharyngeal opening. Animal investigation Mongrel dogs (two) were selected for the experiment, as the Eustachian tubes in the dog correspond closely with those in man. Experimentally, total stenosis of the Eustachian tube was obtained by stitching together the lips of the torus tuberius on both the sides. This was accomplished under 193
V. K. Misurya direct vision by the transpalatal route in an anaesthetized dog. Then the tympano-nasopharyngeal shunt operation was performed in one ear (right) whereas the other ear (left) was taken as a control. The dogs were kept under observation for six months.
wire knot
sificone tube
FIG. 4. Different stages of tympano-nasopharyngeal shunt operation. A. Different parts of bony tensor tympani canal (17-mm. diameter): 1. exit for tensor tympani tendon; 2. tympanic portion—posterior half (3 mm.); 3. tympanic portion—anterior half (3 mm.); 4. proto-tympanic portion (12-mm. length); 5. anterior blind end. B. Only the anterior half of the tympanic portion of the tensor tympani canal (part 3) is drilled to expose the muscle, which is curetted. C. Silicone tube introduced in tensor tympani canal. D and E. Silicone tube anchored to tensor tympani canal by stainless steel wire.
FIG. 5. Diagram showing silicone tube within 'new' Eustachian tube: 1, 2, 3, 4, 5. different parts of tensor tympani canal (ry-mm. diameter); 6. silicone tube; 7. Eustachian tube—osseous part; 8. cartilagenous part; 9. wire anchoring the tube with tensor tympani canal.
These dogs tolerated the surgical procedure well and experienced no untoward effect. The ear with the tympano-nasopharyngeal shunt facility (right) remained normal; but the ear without the tympano-nasopharyngeal shunt facility started discharging after three days. 194
Tympano-nasopharyngeal shunt operation The middle ear was explored after six months. The silicone tube was well in place and patent. Although there was slight granulation tissue around the tube it was not enough to block the wide mouth of the tube. Selection of cases During mastoidectomy or tympanoplasty there may be cases in whom the Eustachian tube is impassible to retrograde probing (from the middle ear). Such cases of total stenosis of the Eustachian tube cannot be managed by tubal tamponade. These individuals may be suitable for the tympanonasopharyngeal shunt operation. Case reports
Case i : A seventeen-year-old boy had been treated since 1965 for chronic serous otitis media of the right ear by adenotonsillectomy, decongestants and repeated myrintotomies with only temporary relief. Several attempts to inflate the middle ear through the Eustachian tube by means of Valsalva, Politerization and Eustachian catheter insufflation had failed. In October 1972 an Armstrong tube was inserted but was extruded after twenty days with recurrence of disease. On 2 January 1973 a mastoidectomy with atticotomy was performed. Gluey material was present within the mastoid air cells and in the middle ear. A probe could not be passed through the Eustachian tube. Then the T-N shunt operation was performed in the right ear.
1
-10 0 B )T 10 A > \ 20
r
1
5
1
1
N
'•—.
40
B-J( jn.16 ,197
60
\
A-Dec. 20,1972
80 100
250
1000 4000 500 2000 8000
AIR CONDUCTION 0 - 0 right x—x left
BONE CONDUCTION C right ] left
FIG. 6. Pure-tone audiogram of Case 1.
Postoperatively there was improvement in the hearing (Fig. 6). Now the middle ear remained air-filled and the patient was able to innate his ear by the Valsalva manoeuvre. One year has elapsed postoperatively; the silicone tube is still patent and the patient is not inconvenienced by it. 195
V. K. Misurya Case 2 : Twenty-year-old female. HISTORY : Hearing loss, both ears, for eight years. EXAMINATION : Ear drum intact but partially mobile. TREATMENT: Armstrong tube gave temporary relief;
T-N shunt operation was done in the right ear in February 1973 (Eustachian tube was impassible with probe). POSTOPERATIVE COURSE: Tympanic membrane mobile; patient could inflate middle ears easily; hearing improved (postoperatively eleven months elapsed). Case 3 : Sixteen-year-old female. HISTORY : Recurrent deafness and discharge left ear since age of five years. EXAMINATION : Tympanic membrane retracted, with healed perforation. TREATMENT: Adenoidectomy, decongestants and repeated myrintotomies gave
temporary relief. In April 1973 T-N shunt operation with mastoidectomy was done; middle ear and mastoid cavity were rilled with gluey transudate but otherwise normal; Eustachian tube was impassable. POSTOPERATIVE COURSE: Patient is asymptomatic so far; middle ear has remain air-filled and T-N shunt is patent (ten-month follow-up). Case 4: Eighteen-year-old male. Recurrent deafness in right ear since age of six years. EXAMINATION : Tympanic membrane retracted and immobile. TREATMENT: Adenoidectomy, decongestants, repeated myrintotomies gave temporary relief. Measures to inflate middle ear through Eustachian tube by means of Valsalva, Politerization, or catheter. In May 1973 T-N shunt operation with mastoidectomy was done; middle ear and mastoid cavity filled with gluey material, Eustachian tube was impassable. POSTOPERATIVE COURSE: No more attacks of disease since then; T-N shunt is patent and middle ear is air-filled (eight months elapsed postoperatively). HISTORY:
Comment
The efficacy of the tympano-nasopharyngeal shunt device as a 'substitute' Eustachian tube has been proved experimentally in dogs. The true value of the reported method cannot be judged until and unless a long period of observation has elapsed postoperatively on several patients. However, the following comments may be made, keeping in consideration the requirements of an ideal method of middle-ear ventilation. The experimental and clinical study was conducted to determine whether the silicone tube is retained or whether, in common with silicone tubes, it is eventually plagued with granulation tissue. The silicone tube is inert and durable even when implanted in the body for a long time. Therefore there is no risk of foreign-body reaction by the silicone-rubber tube left permanently within the tensor tympani canal. Further, the occurrence of granulation tissue (if it is there at all) would be insufficient to block the wide opening of tube (3-mm. diameter) as has been proved experimentally in dogs. In the present series also the tube remained patent. 196
Tympanonasopharyngeal shunt operation The tube remained well in place in dogs (six months follow-up) as well as in the patients of the present series (one-year follow-up). The silicone tube is kept patent by irrigating it with Ringer's solution through the nasopharyngeal opening of the tube. The irrigating canula is introduced into the nasopharynx through the nose and is directed by a posterior rhinoscopy mirror. There is minimal risk of blockage of the tube as it is of wide bore (3-mm. inner diameter). This procedure seems to provide ventilation and effective drainage of the tympanum. The tympano-nasopharyngeal shunt enables the patient to inflate the middle ear by Valsalva or Politzer manoeuvre. This will play a vital role in mitigating the risk of adhesive process after tympanoplasty. In other methods patients may feel discomfort as the tube passes through the skin or is located in the nasal cavity, while in the present method no patient has complained of discomfort so far. The tympanic membrane remains intact. The risk of ascending infection of the middle ear from nasopharynx cannot be completely ruled out. However, in the present series, no patient has had an attack of otitis media so far. The technical difficulties are moderate. This method can be accomplished in children too. Acknowledgement I wish to express my gratitude to Dr. Joe V. DeSa, Emeritus Professor, Department of Ear, Nose and Throat, King Edward Memorial Hospital, Bombay and Dr. M. V. Kirtane who encouraged and guided me in carrying out this work. REFERENCES ARMSTRONG, B. \V. (1954) Archives of Otolaryngology, 653-4. DRETTNER, B., and EKVALL, L. (1969) Archives of Otolaryngology 90,122-8. Gray's Anatomy, 34th ed. (1967), pp. 1324-5. Longmans, Green and Co., Ltd., Harlow. HOUSE, W. F. (i960) Archives of Otolaryngology, 71, 405-7. , and MILES, J. (1969) Laryngoscope, 79, 1765-82. LAPIDOT, A., and KAPILA, B. (1967) Archives of Otolaryngology, 86, 490-6. SILVERSTEIX, H. (1966) Transactions of American Academy of Ophthalmology and Otolaryngology, 70, 640-2. SIIRALA, V. (1964) Archives of Otolaryngology, 80, 287-96. WUIXSTEIN, H. (i960) Archives of Otolaryngology, 71, 408-11. (1963) Archives of Otolaryngology, 78, 371-85. ZSLLNER, F. (1963) Archives of Otolaryngology, 78, 394-9. M.L.B. Medical College, Jhansi (U.P.), India.
197
THE tympano-nasopharyngeal shunt operation is recommended as a 'substitute' Eustachian tube. An experimental study regarding the efficacy of tympano-nasopharyngeal shunt operation was conducted in two dogs. Finally, four patients with complete tubal stenosis were operated on by this new method within a period of one year, with no postoperative complications. The hearing improved and patients were able to inflate their middle ears. The method is claimed to have the following advantages: permanent ventilation of the middle ear with preservation of an intact drum; the middle-ear pressure can be increased by Valsalva or Politzer manoeuvres; moderate technical difficulties; no risk of postoperative complications; and suitable in children as well as adults. The disadvantages seem to be: drainage not ensured; minor risk of ascending infection. Review of literature
Prior to the concept of tympanoplasty, surgery for the correction of chronic ear disease was connected with control of the infective process. Only when hearing became an important parameter in deciding the result of surgery did it become important to consider Eustachian-tube function. Then the significance of an adequate Eustachian-tube function for maintaining the health and integrity of the tympanic cleft became evident. Zollner (1963) was quick to realize that the Eustachian tube could and must undergo surgical correction in certain cases of chronic ear disease. At the time of surgery he would insert either radio-active material, bougies, silk thread or latterly polythene tube (on suggestion of House, i960) from the middle ear through the Eustachian tube via the nasopharynx to the nasal opening. The inlay was left in place for two weeks to three months depending upon the extent of obstruction. The advantage of tubal tamponade is that it sometimes restores the function of the Eustachian tube, and the ear drum is kept intact. Although Zollner's results were fairly good, he admitted that is was sometimes impossible to reopen the stenosed tube. Less-satisfying results, furthermore, have been reported by others (Wullstein, i960). 189
V. K. Misurya For any of the above methods the Eustachian tube had to have some lumen, however small, for the catheter to be pushed through. Zollner (1963) states that he has been unable to probe or reopen completely obliterated tubes, particularly those where the cartilagenous portion was involved, as in healed tuberculosis. Wullstein (1963) handled total obstruction of the osseous portion of the Eustachian tube during tympanoplasty by blind drilling with a diamond burr and implanted amnion, obtaining a fair result; however, he admitted that he is not likely to try this again in the future. Moreover, the risk of damaging the carotid artery cannot be neglected. House and Miles (1969) have dealt with osseous tubal stenosis by way of a middle fossa approach of the temporal bone, but again the technical difficulty of this method seems to be considerable, with more risk of postoperative complication; and with this approach one cannot deal with stenosis of the cartilagenous Eustachian tube. Armstrong (1954) introduced a simple technique of inserting a plastic tube through a myringotomy opening to provide ventilation and drainage of the middle ear. It is only of temporary value, as sooner or later the plastic tubes will be extruded and the drum will heal. Some devices for fixing the tube have been recommended to obviate this risk, e.g. a small steel wire clip around the handle of malleus (Silverstein, 1906); however, the risk of permanent drum perforation persists. At times, in cases of adhesive otitis media, it is not feasible to introduce a plastic tube through the drum. Moreover, there is no facility for middle-ear inflation, either by a Valsalva manoeuvre or by Politzer inflation. However, in cases where the complete restoration of Eustachian tube function is hoped for, the Armstrong method is of immense value in preventing permanent changes in the middle ear. Lapidot and Kapila (1967) proposed a tympano-oral shunt operation in which Wharton's duct was resected and transplanted to connect the anterior part of the middle ear with the oral cavity. This method was tested only in cadavers. The risk of regurgitation of food through the tube was expected to be minimized by providing a valvular mechanism at the oral end of the tube. The question of viability as well as patency of the transplanted duct, and the fate of the submandibular salivary gland, remained unanswered. This procedure seemed to have more capacity for draining than for ventilating the middle ear. Siirala (1964) introduced a polythene tube under the skin of the meatus from the outside and into the mastoid antrum after mastoidectomy. He provided temporary ventilation of the middle ear by inflation through these polythene tubes. Recently Drettner (1969) has discovered a new method of tympanomaxillary shunt. In this method there is permanent ventilation of the middle ear with preservation of an intact drum; while the middle ear can be inflated by the Valsalva or Politzer manoeuvres. The disadvantages 190
Tympanonasopharyngeal shunt operation seem to be that drainage is not ensured and that there is a minor risk of ascending infection; and of occlusion of the tube. It is unsuitable for children. It is clear from this survey of the presently-known methods that the ideal way of restoring the ventilation of the middle ear is yet to be discovered. The ideal method would fulfil the following requirements: i. permanent ventilation of the middle ear; 2. drainage function; 3. intact tympanic membrane; 4. no permanent discomfort; 5. possibility of overpressure ventilation, e.g. by Valsalva or Politzer manoeuvre; 6. no increased risk of middle-ear infection; 7. negligible risk of surgical complication; 8. minor technical difficulties; 9. that it is applicable in children. The purpose of this paper is to describe a new method—the tympanonasopharyngeal shunt operation—for the management of complete Eustachian-tube stenosis. Material and method
Studies of over fifty temporal bone dissections gave rise to the idea that the anterior end of the canal for the tensor tympani always remains patent, whether the Eustachian tube is stenosed (four bones) or not (forty-six bones). This observation is endorsed by the fact that a few of the muscle fibres of the tensor tympani arise from the cartilagenous Eustachian tube and enter through the medial end of the canal. So it is concluded that the canal for the tensor tympani always remains open at both the ends, even in the presence of tubal stenosis. Secondly, as we know, the tensor tympani canal runs parallel with the whole course of the osseous Eustachian tube and if we pass a probe through the canal of the tensor tympani it will run parallel to the long axis of Eustachian tube (Fig. ia). Theoretically, the Middle Meningeal artery Tensor tympani Eustachean tube
Carotid canal
Probe Tensqrpalati
Cartilage of tube Levator palati
Tegmen
Tympanic bone
Superior constrictor
A. Osseous part
6. Cartilagenous part
FIG. 1. Anatomical relations of Eustachian tube.
probe should appear in the nasopharynx just above the torus tuberius. But in practice it appears in the fossa of Rosenmuller, the reason being that the osseous and cartilagenous parts of the Eustachian tube join at an obtuse angle of 1600 opening outwards (Fig. 2). 191
V. K. Misurya Hence the probe which previously was running along the roof of the osseous Eustachian tube now runs along the postero-medial wall (instead of the roof) of the cartilagenous tube. In this way probing through the canal of the tensor tympani becomes a safe procedure, as the roof and posteromedial aspect of the cartilagenous Eustachian tube are not related to any vital structure. There is no risk of injury to the middle meningeal artery and mandibular nerve as they lie on the anterolateral aspect of the cartilagenous Eustachian tube and remain separated from it by the tensor palati muscle (Fig. ib).
1 Osseus tube 2 Cartilagenous tube 2 3 Canal for tensor tympani 4 Fossa of Rosenmiiller
FIG. 2. Showing obtuse angle (160°) opening outward between bony and cartilagenous part of Eustachian tube.
These above-mentioned facts stimulated the author to evolve a new method—the tympano-nasopharyngeal shunt operation—for tubal stenosis. This newly-devised method has been practised over the Eustachian tubes in ten cadavers. Subsequently the cadavers were dissected to exclude any possibility of damage to the surrounding vital structures. There is no risk of injury to the internal carotid artery as it lies away from the field of operation. This method has proved to be a safe one. The efficacy of the tympano-nasopharyngeal shunt operation was evaluated in artificiallystenosed Eustachian tubes in two dogs. Finally, within one year four cases of complete tubal stenosis in humans have been managed successfully by this new method. Method The tympano-nasopharyngeal shunt operation can be combined with a mastoidectomy or a tympanoplasty. This procedure is undertaken in the following stages: 192
Tympano-nasopharyngeal shunt operation 1. Attico-antrotomy is performed and is extended anteriorly until the tendon of the tensor tympani muscle is visualized. 2. The attachment of the tensor tympani tendon to the neck of the malleus is cut; the anterior half of the bony tensor tympani canal (Fig. 4a(3) is drilled so as to expose the muscle; the tensor tympani muscle is avulsed from its origin, and remaining muscle fibres are curetted from the canal. The posterior half of the canal (Fig. 4a(2) is left intact. 3. Now the silicone tube (Fig. 3), threaded over the introducer (made of stainless steel wire), is introduced through the tensor tympani canal until it comes out into nasopharynx within the fossa of Rosenmiiller (Fig. 2). The introducer during its course slides over the roof of the osseous part and over the postero-medial aspect of the cartilagenous Eustachian tube. Finally, after passing about 38 mm. the introducer is retrieved from the nasopharynx.
FIG. 3. Silicone tube (length 40 mm., inner diameter of wider end 3 mm. and of narrow end^i mm.) with stainless steel wire introducer.
4. The introducer is taken out from the nasopharynx, leaving behind the silicone tube. In this way the silicone tube (approximate dimensions: length 40 mm.; inner diameter of broader end 3 mm., of narrower end 1 mm.) is left in this newly-canalized substitute Eustachian tube (Fig. 5), with its narrower end emerging slightly beyond the pharyngeal opening of the Eustachian tube. 5. The tympanic (broader) end of the silicone tube is anchored to the intact (posterior half) tensor tympani canal, with thin stainless steel wire (Fig. 4e)6. The patency of the tube is checked by irrigation with Ringer's solution which will come out through the nasopharyngeal opening. Animal investigation Mongrel dogs (two) were selected for the experiment, as the Eustachian tubes in the dog correspond closely with those in man. Experimentally, total stenosis of the Eustachian tube was obtained by stitching together the lips of the torus tuberius on both the sides. This was accomplished under 193
V. K. Misurya direct vision by the transpalatal route in an anaesthetized dog. Then the tympano-nasopharyngeal shunt operation was performed in one ear (right) whereas the other ear (left) was taken as a control. The dogs were kept under observation for six months.
wire knot
sificone tube
FIG. 4. Different stages of tympano-nasopharyngeal shunt operation. A. Different parts of bony tensor tympani canal (17-mm. diameter): 1. exit for tensor tympani tendon; 2. tympanic portion—posterior half (3 mm.); 3. tympanic portion—anterior half (3 mm.); 4. proto-tympanic portion (12-mm. length); 5. anterior blind end. B. Only the anterior half of the tympanic portion of the tensor tympani canal (part 3) is drilled to expose the muscle, which is curetted. C. Silicone tube introduced in tensor tympani canal. D and E. Silicone tube anchored to tensor tympani canal by stainless steel wire.
FIG. 5. Diagram showing silicone tube within 'new' Eustachian tube: 1, 2, 3, 4, 5. different parts of tensor tympani canal (ry-mm. diameter); 6. silicone tube; 7. Eustachian tube—osseous part; 8. cartilagenous part; 9. wire anchoring the tube with tensor tympani canal.
These dogs tolerated the surgical procedure well and experienced no untoward effect. The ear with the tympano-nasopharyngeal shunt facility (right) remained normal; but the ear without the tympano-nasopharyngeal shunt facility started discharging after three days. 194
Tympano-nasopharyngeal shunt operation The middle ear was explored after six months. The silicone tube was well in place and patent. Although there was slight granulation tissue around the tube it was not enough to block the wide mouth of the tube. Selection of cases During mastoidectomy or tympanoplasty there may be cases in whom the Eustachian tube is impassible to retrograde probing (from the middle ear). Such cases of total stenosis of the Eustachian tube cannot be managed by tubal tamponade. These individuals may be suitable for the tympanonasopharyngeal shunt operation. Case reports
Case i : A seventeen-year-old boy had been treated since 1965 for chronic serous otitis media of the right ear by adenotonsillectomy, decongestants and repeated myrintotomies with only temporary relief. Several attempts to inflate the middle ear through the Eustachian tube by means of Valsalva, Politerization and Eustachian catheter insufflation had failed. In October 1972 an Armstrong tube was inserted but was extruded after twenty days with recurrence of disease. On 2 January 1973 a mastoidectomy with atticotomy was performed. Gluey material was present within the mastoid air cells and in the middle ear. A probe could not be passed through the Eustachian tube. Then the T-N shunt operation was performed in the right ear.
1
-10 0 B )T 10 A > \ 20
r
1
5
1
1
N
'•—.
40
B-J( jn.16 ,197
60
\
A-Dec. 20,1972
80 100
250
1000 4000 500 2000 8000
AIR CONDUCTION 0 - 0 right x—x left
BONE CONDUCTION C right ] left
FIG. 6. Pure-tone audiogram of Case 1.
Postoperatively there was improvement in the hearing (Fig. 6). Now the middle ear remained air-filled and the patient was able to innate his ear by the Valsalva manoeuvre. One year has elapsed postoperatively; the silicone tube is still patent and the patient is not inconvenienced by it. 195
V. K. Misurya Case 2 : Twenty-year-old female. HISTORY : Hearing loss, both ears, for eight years. EXAMINATION : Ear drum intact but partially mobile. TREATMENT: Armstrong tube gave temporary relief;
T-N shunt operation was done in the right ear in February 1973 (Eustachian tube was impassible with probe). POSTOPERATIVE COURSE: Tympanic membrane mobile; patient could inflate middle ears easily; hearing improved (postoperatively eleven months elapsed). Case 3 : Sixteen-year-old female. HISTORY : Recurrent deafness and discharge left ear since age of five years. EXAMINATION : Tympanic membrane retracted, with healed perforation. TREATMENT: Adenoidectomy, decongestants and repeated myrintotomies gave
temporary relief. In April 1973 T-N shunt operation with mastoidectomy was done; middle ear and mastoid cavity were rilled with gluey transudate but otherwise normal; Eustachian tube was impassable. POSTOPERATIVE COURSE: Patient is asymptomatic so far; middle ear has remain air-filled and T-N shunt is patent (ten-month follow-up). Case 4: Eighteen-year-old male. Recurrent deafness in right ear since age of six years. EXAMINATION : Tympanic membrane retracted and immobile. TREATMENT: Adenoidectomy, decongestants, repeated myrintotomies gave temporary relief. Measures to inflate middle ear through Eustachian tube by means of Valsalva, Politerization, or catheter. In May 1973 T-N shunt operation with mastoidectomy was done; middle ear and mastoid cavity filled with gluey material, Eustachian tube was impassable. POSTOPERATIVE COURSE: No more attacks of disease since then; T-N shunt is patent and middle ear is air-filled (eight months elapsed postoperatively). HISTORY:
Comment
The efficacy of the tympano-nasopharyngeal shunt device as a 'substitute' Eustachian tube has been proved experimentally in dogs. The true value of the reported method cannot be judged until and unless a long period of observation has elapsed postoperatively on several patients. However, the following comments may be made, keeping in consideration the requirements of an ideal method of middle-ear ventilation. The experimental and clinical study was conducted to determine whether the silicone tube is retained or whether, in common with silicone tubes, it is eventually plagued with granulation tissue. The silicone tube is inert and durable even when implanted in the body for a long time. Therefore there is no risk of foreign-body reaction by the silicone-rubber tube left permanently within the tensor tympani canal. Further, the occurrence of granulation tissue (if it is there at all) would be insufficient to block the wide opening of tube (3-mm. diameter) as has been proved experimentally in dogs. In the present series also the tube remained patent. 196
Tympanonasopharyngeal shunt operation The tube remained well in place in dogs (six months follow-up) as well as in the patients of the present series (one-year follow-up). The silicone tube is kept patent by irrigating it with Ringer's solution through the nasopharyngeal opening of the tube. The irrigating canula is introduced into the nasopharynx through the nose and is directed by a posterior rhinoscopy mirror. There is minimal risk of blockage of the tube as it is of wide bore (3-mm. inner diameter). This procedure seems to provide ventilation and effective drainage of the tympanum. The tympano-nasopharyngeal shunt enables the patient to inflate the middle ear by Valsalva or Politzer manoeuvre. This will play a vital role in mitigating the risk of adhesive process after tympanoplasty. In other methods patients may feel discomfort as the tube passes through the skin or is located in the nasal cavity, while in the present method no patient has complained of discomfort so far. The tympanic membrane remains intact. The risk of ascending infection of the middle ear from nasopharynx cannot be completely ruled out. However, in the present series, no patient has had an attack of otitis media so far. The technical difficulties are moderate. This method can be accomplished in children too. Acknowledgement I wish to express my gratitude to Dr. Joe V. DeSa, Emeritus Professor, Department of Ear, Nose and Throat, King Edward Memorial Hospital, Bombay and Dr. M. V. Kirtane who encouraged and guided me in carrying out this work. REFERENCES ARMSTRONG, B. \V. (1954) Archives of Otolaryngology, 653-4. DRETTNER, B., and EKVALL, L. (1969) Archives of Otolaryngology 90,122-8. Gray's Anatomy, 34th ed. (1967), pp. 1324-5. Longmans, Green and Co., Ltd., Harlow. HOUSE, W. F. (i960) Archives of Otolaryngology, 71, 405-7. , and MILES, J. (1969) Laryngoscope, 79, 1765-82. LAPIDOT, A., and KAPILA, B. (1967) Archives of Otolaryngology, 86, 490-6. SILVERSTEIX, H. (1966) Transactions of American Academy of Ophthalmology and Otolaryngology, 70, 640-2. SIIRALA, V. (1964) Archives of Otolaryngology, 80, 287-96. WUIXSTEIN, H. (i960) Archives of Otolaryngology, 71, 408-11. (1963) Archives of Otolaryngology, 78, 371-85. ZSLLNER, F. (1963) Archives of Otolaryngology, 78, 394-9. M.L.B. Medical College, Jhansi (U.P.), India.
197
