Clin. O/o/aryngn/.1992, 17, 258-260
What is the best method of treatment for labyrinthine fistulae caused by cholesteatorna? EERO VARTIAINEN Department of Otolaryngology. University of Kuopio. SF-70200 Kuopio, Finland Accepted for publication 4 November 1991 V A R T I A I N E N E.
(1992) Clin. Otolaryngol. 17, 258-260
What is the best method of treatment for labyrinthine fistulae caused by cholesteatoma? A series of 19 patients with a labyrinthine fistula causcd by cholesteatoma was analysed. Two patients presented with acutc suppurative labyrinthitis and meningitis. A canal wall down procedure was performed in all but one patient. Of the 17 patients with prcserved inner-ear function, the cholesteatoma matrix over the fistula was removed in 10 resulting in severe sensorineural hearing loss in one of these. Thc matrix was left in situ in 7 patients and hearing was maintained or improved in all of them. Post-operatively, 2 patients suffered from vestibular disturbances, the matrix covering the fistula being removed in both of them. It was concluded that preservation of the matrix over the fistula is the safest method of management of this serious complication of cholesteatomatous chronic ear disease. Kcywords
chronic otitis meciiu
ear surgery
Labyrinthine fistulae are serious complications of chronic otitis media with cholcsteatoma and they can result in vertigo, sensorineural hearing loss, purulent labyrinthitis and meningitis. Although other life-threatening complications of chronic otorrhea have been mostly prevented during the past decades, the incidence of labyrinthine fistulae has been stable at about 10% of cases of chronic mastoiditis with mastoidectomy.'.* The presence of symptoms indicating a labyrinthine disorder in a patient with chronic ear disease is an absolute indication for immediate ~ u r g e r yHowever, .~ controversy still exists among otologists regarding both the best surgical approach and the management of the cholcsteatoma matrix over the fistula, i.e. should it be removed or left in situ during surgery? In an attempt to answer these questions the longterm results of surgical treatment of paticnts with a labyrinthine fistula caused by cholesteatoma have been studied.
Material and methods The material studied consists of 19 patients with a labyrinthine fistula caused by cholcsteatomatous chronic otitis media treated in the Department of Otolaryngology, University of Kuopio, Kuopio, Finland, between 1970 and 1985. Of the 19 patients, 10 wcre male and 9 were female.
The average age at the time of surgery was 42.3 years, ranging from 15 to 62 years. On presentation, all ears were discharging. Fifteen patients had primary acquired cholesteatoma with either an attic perforation (9 patients) or a posterosuperior perforation (6 patients). Two patients had a secondary acquired cholestcatoma with total pars tensa perforations and a further 2 patients had recurrent cholesteatorna. At surgery, in 6 patients (32%) the cholesteatoma was found to be hugc, tilling the entire mastoid air cell system, in 12 patients it was confincd to the antrum, and in one limited to the middle ear scgmen t. Two patients were admitted as an emcrgency with acutc suppurative labyrinthitis and meningitis; both these patients underwent radical mastoidectomy and partial labyrinthectomy. The fistula was located on the promontory in one of these and in the lateral semicircular canal in the other. Seventeen patients underwent elective surgery. Four ears had been rendered dry by preoperative medical treatment; the remaining 13 ears wcre discharging at operation. 16 of the fistulae detected in these ears were confined to the lateral semicircular canal and one was more extensive involving both the lateral and the superior semicircular canal. Sixteen of these 17 patients underwent canal wall down mastoidectomy with simultaneous tympanoplasty and one paticnt was
Labyrinthine Jistula 259
Table 1. Post-operative bone-conduction thresholds (0.5-4 kHz) A change of 15 dB or more was considered significant Matrix
Matrix
removed
preserved
_____
Table 2. Mean air-conduction thresholds (0.5-2 kHz). A change of 15 dB or more was considered significant
Matrix removed
Total (YO)
n
(YO)
Matrix preserved n (YO)
Total n
(YO)
Improved
Same Deteriorated Total
7 I
-
10
Mean hearing level, dB (s.d.)
subjected to intact canal wall mastoidectomy. The cholesteatoma matrix over the fistula was preserved in 7 of these ears and an open cavity was created. In 10 patients the matrix was completely removed at the final stage of the operation and the fistula covered with fascia; in 4 of these ears the posterior canal wall was constructed with fascia and the cavity obliterated with a musculoperiosteal flap. In the remaining 6 ears the fistula site was left open but the cavity posterior and superior to the fistula was obliterated with a soft tissue flap. Temporal muscle fascia was placed under the tympanic membrane remnant to seal the mesotympanum in all these 17 ears. Ossicular reconstruction using cortical bone was performed in 10 ears; the columella was placed between the stapes and the grafted tympanic membrane in 7 and between the footplate and the tympanic membrane in 3. No ossicular reconstruction was attempted in 7 ears. After surgery, all patients were regularly checked in the out-patient department. The mean follow-up period was 7.6 years (range 3-14 years). Audiological examination was performed using a clinical audiometer calibrated according to I S 0 standards. Audiograms obtained the day before operation and at the last follow-up visit or thc day before revision operation were used for comparison.
Results VERTIGO
Two patients with suppurative labyrinthitis and meningitis recovered completely after surgical and medical therapy. Of the other 17 patients, I 1 (65%) experienced episodic vertigo preoperatively and the fistula test performed with a pneumatic speculum was positive in 10 (91%) of them. Nine of these 11 patients were free of vestibular symptoms at followup. One patient, in whom the matrix over the fistula site was removed and mastoidectomy cavity partly obliterated, suffered from recurrent attacks of vertigo induced by mechanical irritation. He underwent cavity obliteration as a revision operation 6 months after the primary surgery and has since had no vertigo. Another patient continues to report vertigo in association with sudden movement 5 years postoperatively; the cholesteatoma matrix was removed also in this case.
Preoperatively Post-operatively
45.9 (k19.4) 47.1 (k18.3) 46.4 (k19.0) 38.2 (k21.5) 44.0 (_+15.6) 40.6 (k19.5)
Six patients did not report vestibular disturbances preoperatively and none of them had vertigo after surgery. The fistula test was not recorded in these patients. HEARING
Two ears were totally deaf preoperatively (the patients with purulent labyrinthitis). Ten patients initially had a pure conductive hearing loss and 7 had a mixed hearing loss. After surgery, one patient showed a severe sensonneural hearing loss (his hearing dropped from a level of 42 dB preoperatively to a level of 88 d B post-operatively); the cholesteatoma matrix over the fistula was removed in this case. In no other instance did bone-conduction thresholds (0.5-4 kHz) deteriorate by 15 dB or more during follow-up (Table I). Of the 3 patients with improved bone-conduction thresholds, the matrix was removed in 2 and left in place in one. Air-conduction thresholds deteriorated in one patient (the above mentioned case with sensorineural hearing loss), remained unchanged in 12 patients and improved in 4 patients (Table 2). Patients in whom the colesteatoma matrix was removed completely had slightly (but not significantly) better long-term hearing results than those patients in whom the matrix was retained as measured by the change of mean air-conduction thresholds. At the last follow-up examination, 5 patients (29%) had serviceable ( < 30 dB) hearing level in the ear operated on. R E C U R R E N C E OF CHOLESTEATOMA
During follow-up, residual cholesteatoma was detected in 2 (10.5%) of the 19 patients. One of these was the only patient undergoing intact canal wall mastoidectomy; the other patient had been treated with canal wall down mastoidectomy and cavity obliteration. In both these patients the cholesteatoma matrix was removed during the primary operation. After revision surgery, hearing was maintained in both of these ears.
260 E. Vartiainen
Discussion In thc literature, no agreement has been reached as to how a labyrinthine fistula due to cholesteatoma should be managed. Several authors recommend canal wall down mastoidectomy.2.'8 Tos' advocated modified radical mastoidectomy with reconstruction of the posterior meatal wall and cavity obliteration. Some authors favour intact canal wall mastoidectomy , usually as a two-stage procedure. I", I I We prefer canal wall down mastoidectomy bccause it provides the best exposure to the fistula site. This procedure does not preclude simultaneous tympanoplasty. The management of the matrix over the fistula remains the most controversial subject. In spite of the risk of producing a severe sensorineural hearing loss, most authors advocate careful removal of the matrix from the fistula either at primary surgery or during the second stage on an intact canal wall mastoidectomy.3~7~'~10~~2~'' In published series, the incidence of complete deafness following this surgical technique varies between 0 and 22%.2.4.7-'1,'3 Gacek6 removed the matrix from small fistulae or left it in situ if the matrix was strongly adherent or the fistula was large. Sheehy and Brackmanl' recommended that its removal be governed by the size of the fistula, the dryness of the ear, the sensorineural function of the involved ear, and the status of the opposite ear. Earlier, Ritter14 and more recently Smyth and Gormley' stated that removal of the matrix is the critical factor in sensorineural hearing impairment and concluded that it is wisest to leave the matrix on the fistula. In the present series, the only severe sensorineural hearing loss that resulted from the surgical procedure occurred after removal of the matrix whereas in no patient in whom the matrix was preserved was there a decrease in bone conduction after surgery. Recently, Parisier et a1.' stated that thin, clean matrix can be preserved over large or multiple fistulae but hyperplastic or inflamed matrix should be removed to prevent continued bone destruction or labyrinthitis. Palva et al.' have reported one patient in whom, 3 years after a matrix-preserving operation, suppurative labyrinthitis arose resulting in a dead ear. Otherwise, no serious consequences of permanent retention of the matrix have been reported.' None of our patients in whom the cholesteatoma matrix was left over the fistula experienced any trouble post-operatively. During the followup period, residual cholesteatoma developed in 2 patients; the matrix was removed at the primary operation in both of them. Based on the data above, it is reasonable to conclude that preservation of the cholesteatoma matrix over the fistula is the safest method of management to avoid inner ear damage.
Kobayashi et a/." have presented a scries of 5 patients with labyrinthine fistulae caused by cholesteatoma, in whom an improvement in bone conduction of a t least 30 dB was observed after surgical and antibiotic therapy. The authors considered these cases to be in the stage of serous labyrinthitis. In 3 (18%) of our patients bone conduction thresholds improved significantly (by I5 dB or more) post-operatively. Thus, tympanoplasty in chronic ears with a labyrinthine fistula is worthwhile even in patients with markedly reduced bone conduction.
References 1
2
3
4 5
MCCABEB. (1984) Labyrinthine fistula in chronic mastoiditis. Ann. Otol. Rhinol. Laryngol. 93 (Suppl. 112), 138-141 PARISIERS.C., EDELSTEIN D.R., HANJ.C. & WEISSM.H. (1991) Management of labyrinthine fistulas coased by cholesteatoma. Otolaryngol. Head Neck Surg. 104, 110-1 15 PFALTZC.R. (1982) Complications of otitis media. O R L 44, 301-309 ARRAMSON M. (1974) Labyrinthine fistula complicating chronic suppurative otitis media. Arch. Otolaryngol. 100, 141-142 FREEMAN P. (1978) Fistula of the lateral semicircular canal. C h .
Otolaryngol. 3, 315-321 6 GACEKR.R. (1974) The surgical management of labyrinthine fistulae in chronic otitis media with cholesteatoma. Ann. Otol. Rhinol. Laryngol. 83 (Suppl. lo), 3-19 7 PALVA T., KARJAJ. & PALVA A. (1971) Opening of the labyrinth during chronic ear surgery. Arch. Otolaryngol, 93, 75-78 8 SMYTH G.D.L. & GORMLEY P.K. (1987) Preservation of cochlear function in the surgery of cholesteatomatouslabyrinthine fistulas and oval window tympanosclerosis. Otolaryngol. Head Neck Surg. 96, 111-118 9 Ttm M (1975) Treatment of labyrinthine fistulae by a closed technique. ORL 37, 41-47 M., ZINIC., GAMOLETTI R., TAIBAH A.K., Russo A. & 10 SANNA SCANDELLARI R. (1988) Closed versus open technique in the management of labyrinthine fistulae. Am. J . Otol. 9, 470-475 11 SHEEHY J.L. & BRACKMANN D.E. (1979) Cholesteatoma surgery: Management of the labyrinthine fistula-a report of 97 cases. Laryngoscope 89, 78-87 12 SZPUNAR J. (1976) Labyrinthine fistula and tympanoplasty. Ann. Otol. Rhinol. Laryngol. 85, 291-298 13 OSTRIB. & BAK-PEDERSEN K. (1989) Surgical management of labyrinthine fistulae in chronic otitis media with cholesteatoma by a one-stage closed technique. O R L 51, 295-299 14 RITTERF.N.(1970) Chronic suppurative otitis media and the pathologic labyrinthine fistula. Laryngoscope 80, 1025-1035 I 5 KOBAYASHI T., SAKURAI T., OKITSU T., YUASA R., KAWASE T., J. & TAKASAKA T. (1989) Labyrinthine fistula caused KUSAKARI by cholesteatoma. Improved bond conduction by trcatrnent. A m . J . Otol. 10, 5-10.
What is the best method of treatment for labyrinthine fistulae caused by cholesteatorna? EERO VARTIAINEN Department of Otolaryngology. University of Kuopio. SF-70200 Kuopio, Finland Accepted for publication 4 November 1991 V A R T I A I N E N E.
(1992) Clin. Otolaryngol. 17, 258-260
What is the best method of treatment for labyrinthine fistulae caused by cholesteatoma? A series of 19 patients with a labyrinthine fistula causcd by cholesteatoma was analysed. Two patients presented with acutc suppurative labyrinthitis and meningitis. A canal wall down procedure was performed in all but one patient. Of the 17 patients with prcserved inner-ear function, the cholesteatoma matrix over the fistula was removed in 10 resulting in severe sensorineural hearing loss in one of these. Thc matrix was left in situ in 7 patients and hearing was maintained or improved in all of them. Post-operatively, 2 patients suffered from vestibular disturbances, the matrix covering the fistula being removed in both of them. It was concluded that preservation of the matrix over the fistula is the safest method of management of this serious complication of cholesteatomatous chronic ear disease. Kcywords
chronic otitis meciiu
ear surgery
Labyrinthine fistulae are serious complications of chronic otitis media with cholcsteatoma and they can result in vertigo, sensorineural hearing loss, purulent labyrinthitis and meningitis. Although other life-threatening complications of chronic otorrhea have been mostly prevented during the past decades, the incidence of labyrinthine fistulae has been stable at about 10% of cases of chronic mastoiditis with mastoidectomy.'.* The presence of symptoms indicating a labyrinthine disorder in a patient with chronic ear disease is an absolute indication for immediate ~ u r g e r yHowever, .~ controversy still exists among otologists regarding both the best surgical approach and the management of the cholcsteatoma matrix over the fistula, i.e. should it be removed or left in situ during surgery? In an attempt to answer these questions the longterm results of surgical treatment of paticnts with a labyrinthine fistula caused by cholesteatoma have been studied.
Material and methods The material studied consists of 19 patients with a labyrinthine fistula caused by cholcsteatomatous chronic otitis media treated in the Department of Otolaryngology, University of Kuopio, Kuopio, Finland, between 1970 and 1985. Of the 19 patients, 10 wcre male and 9 were female.
The average age at the time of surgery was 42.3 years, ranging from 15 to 62 years. On presentation, all ears were discharging. Fifteen patients had primary acquired cholesteatoma with either an attic perforation (9 patients) or a posterosuperior perforation (6 patients). Two patients had a secondary acquired cholestcatoma with total pars tensa perforations and a further 2 patients had recurrent cholesteatorna. At surgery, in 6 patients (32%) the cholesteatoma was found to be hugc, tilling the entire mastoid air cell system, in 12 patients it was confincd to the antrum, and in one limited to the middle ear scgmen t. Two patients were admitted as an emcrgency with acutc suppurative labyrinthitis and meningitis; both these patients underwent radical mastoidectomy and partial labyrinthectomy. The fistula was located on the promontory in one of these and in the lateral semicircular canal in the other. Seventeen patients underwent elective surgery. Four ears had been rendered dry by preoperative medical treatment; the remaining 13 ears wcre discharging at operation. 16 of the fistulae detected in these ears were confined to the lateral semicircular canal and one was more extensive involving both the lateral and the superior semicircular canal. Sixteen of these 17 patients underwent canal wall down mastoidectomy with simultaneous tympanoplasty and one paticnt was
Labyrinthine Jistula 259
Table 1. Post-operative bone-conduction thresholds (0.5-4 kHz) A change of 15 dB or more was considered significant Matrix
Matrix
removed
preserved
_____
Table 2. Mean air-conduction thresholds (0.5-2 kHz). A change of 15 dB or more was considered significant
Matrix removed
Total (YO)
n
(YO)
Matrix preserved n (YO)
Total n
(YO)
Improved
Same Deteriorated Total
7 I
-
10
Mean hearing level, dB (s.d.)
subjected to intact canal wall mastoidectomy. The cholesteatoma matrix over the fistula was preserved in 7 of these ears and an open cavity was created. In 10 patients the matrix was completely removed at the final stage of the operation and the fistula covered with fascia; in 4 of these ears the posterior canal wall was constructed with fascia and the cavity obliterated with a musculoperiosteal flap. In the remaining 6 ears the fistula site was left open but the cavity posterior and superior to the fistula was obliterated with a soft tissue flap. Temporal muscle fascia was placed under the tympanic membrane remnant to seal the mesotympanum in all these 17 ears. Ossicular reconstruction using cortical bone was performed in 10 ears; the columella was placed between the stapes and the grafted tympanic membrane in 7 and between the footplate and the tympanic membrane in 3. No ossicular reconstruction was attempted in 7 ears. After surgery, all patients were regularly checked in the out-patient department. The mean follow-up period was 7.6 years (range 3-14 years). Audiological examination was performed using a clinical audiometer calibrated according to I S 0 standards. Audiograms obtained the day before operation and at the last follow-up visit or thc day before revision operation were used for comparison.
Results VERTIGO
Two patients with suppurative labyrinthitis and meningitis recovered completely after surgical and medical therapy. Of the other 17 patients, I 1 (65%) experienced episodic vertigo preoperatively and the fistula test performed with a pneumatic speculum was positive in 10 (91%) of them. Nine of these 11 patients were free of vestibular symptoms at followup. One patient, in whom the matrix over the fistula site was removed and mastoidectomy cavity partly obliterated, suffered from recurrent attacks of vertigo induced by mechanical irritation. He underwent cavity obliteration as a revision operation 6 months after the primary surgery and has since had no vertigo. Another patient continues to report vertigo in association with sudden movement 5 years postoperatively; the cholesteatoma matrix was removed also in this case.
Preoperatively Post-operatively
45.9 (k19.4) 47.1 (k18.3) 46.4 (k19.0) 38.2 (k21.5) 44.0 (_+15.6) 40.6 (k19.5)
Six patients did not report vestibular disturbances preoperatively and none of them had vertigo after surgery. The fistula test was not recorded in these patients. HEARING
Two ears were totally deaf preoperatively (the patients with purulent labyrinthitis). Ten patients initially had a pure conductive hearing loss and 7 had a mixed hearing loss. After surgery, one patient showed a severe sensonneural hearing loss (his hearing dropped from a level of 42 dB preoperatively to a level of 88 d B post-operatively); the cholesteatoma matrix over the fistula was removed in this case. In no other instance did bone-conduction thresholds (0.5-4 kHz) deteriorate by 15 dB or more during follow-up (Table I). Of the 3 patients with improved bone-conduction thresholds, the matrix was removed in 2 and left in place in one. Air-conduction thresholds deteriorated in one patient (the above mentioned case with sensorineural hearing loss), remained unchanged in 12 patients and improved in 4 patients (Table 2). Patients in whom the colesteatoma matrix was removed completely had slightly (but not significantly) better long-term hearing results than those patients in whom the matrix was retained as measured by the change of mean air-conduction thresholds. At the last follow-up examination, 5 patients (29%) had serviceable ( < 30 dB) hearing level in the ear operated on. R E C U R R E N C E OF CHOLESTEATOMA
During follow-up, residual cholesteatoma was detected in 2 (10.5%) of the 19 patients. One of these was the only patient undergoing intact canal wall mastoidectomy; the other patient had been treated with canal wall down mastoidectomy and cavity obliteration. In both these patients the cholesteatoma matrix was removed during the primary operation. After revision surgery, hearing was maintained in both of these ears.
260 E. Vartiainen
Discussion In thc literature, no agreement has been reached as to how a labyrinthine fistula due to cholesteatoma should be managed. Several authors recommend canal wall down mastoidectomy.2.'8 Tos' advocated modified radical mastoidectomy with reconstruction of the posterior meatal wall and cavity obliteration. Some authors favour intact canal wall mastoidectomy , usually as a two-stage procedure. I", I I We prefer canal wall down mastoidectomy bccause it provides the best exposure to the fistula site. This procedure does not preclude simultaneous tympanoplasty. The management of the matrix over the fistula remains the most controversial subject. In spite of the risk of producing a severe sensorineural hearing loss, most authors advocate careful removal of the matrix from the fistula either at primary surgery or during the second stage on an intact canal wall mastoidectomy.3~7~'~10~~2~'' In published series, the incidence of complete deafness following this surgical technique varies between 0 and 22%.2.4.7-'1,'3 Gacek6 removed the matrix from small fistulae or left it in situ if the matrix was strongly adherent or the fistula was large. Sheehy and Brackmanl' recommended that its removal be governed by the size of the fistula, the dryness of the ear, the sensorineural function of the involved ear, and the status of the opposite ear. Earlier, Ritter14 and more recently Smyth and Gormley' stated that removal of the matrix is the critical factor in sensorineural hearing impairment and concluded that it is wisest to leave the matrix on the fistula. In the present series, the only severe sensorineural hearing loss that resulted from the surgical procedure occurred after removal of the matrix whereas in no patient in whom the matrix was preserved was there a decrease in bone conduction after surgery. Recently, Parisier et a1.' stated that thin, clean matrix can be preserved over large or multiple fistulae but hyperplastic or inflamed matrix should be removed to prevent continued bone destruction or labyrinthitis. Palva et al.' have reported one patient in whom, 3 years after a matrix-preserving operation, suppurative labyrinthitis arose resulting in a dead ear. Otherwise, no serious consequences of permanent retention of the matrix have been reported.' None of our patients in whom the cholesteatoma matrix was left over the fistula experienced any trouble post-operatively. During the followup period, residual cholesteatoma developed in 2 patients; the matrix was removed at the primary operation in both of them. Based on the data above, it is reasonable to conclude that preservation of the cholesteatoma matrix over the fistula is the safest method of management to avoid inner ear damage.
Kobayashi et a/." have presented a scries of 5 patients with labyrinthine fistulae caused by cholesteatoma, in whom an improvement in bone conduction of a t least 30 dB was observed after surgical and antibiotic therapy. The authors considered these cases to be in the stage of serous labyrinthitis. In 3 (18%) of our patients bone conduction thresholds improved significantly (by I5 dB or more) post-operatively. Thus, tympanoplasty in chronic ears with a labyrinthine fistula is worthwhile even in patients with markedly reduced bone conduction.
References 1
2
3
4 5
MCCABEB. (1984) Labyrinthine fistula in chronic mastoiditis. Ann. Otol. Rhinol. Laryngol. 93 (Suppl. 112), 138-141 PARISIERS.C., EDELSTEIN D.R., HANJ.C. & WEISSM.H. (1991) Management of labyrinthine fistulas coased by cholesteatoma. Otolaryngol. Head Neck Surg. 104, 110-1 15 PFALTZC.R. (1982) Complications of otitis media. O R L 44, 301-309 ARRAMSON M. (1974) Labyrinthine fistula complicating chronic suppurative otitis media. Arch. Otolaryngol. 100, 141-142 FREEMAN P. (1978) Fistula of the lateral semicircular canal. C h .
Otolaryngol. 3, 315-321 6 GACEKR.R. (1974) The surgical management of labyrinthine fistulae in chronic otitis media with cholesteatoma. Ann. Otol. Rhinol. Laryngol. 83 (Suppl. lo), 3-19 7 PALVA T., KARJAJ. & PALVA A. (1971) Opening of the labyrinth during chronic ear surgery. Arch. Otolaryngol, 93, 75-78 8 SMYTH G.D.L. & GORMLEY P.K. (1987) Preservation of cochlear function in the surgery of cholesteatomatouslabyrinthine fistulas and oval window tympanosclerosis. Otolaryngol. Head Neck Surg. 96, 111-118 9 Ttm M (1975) Treatment of labyrinthine fistulae by a closed technique. ORL 37, 41-47 M., ZINIC., GAMOLETTI R., TAIBAH A.K., Russo A. & 10 SANNA SCANDELLARI R. (1988) Closed versus open technique in the management of labyrinthine fistulae. Am. J . Otol. 9, 470-475 11 SHEEHY J.L. & BRACKMANN D.E. (1979) Cholesteatoma surgery: Management of the labyrinthine fistula-a report of 97 cases. Laryngoscope 89, 78-87 12 SZPUNAR J. (1976) Labyrinthine fistula and tympanoplasty. Ann. Otol. Rhinol. Laryngol. 85, 291-298 13 OSTRIB. & BAK-PEDERSEN K. (1989) Surgical management of labyrinthine fistulae in chronic otitis media with cholesteatoma by a one-stage closed technique. O R L 51, 295-299 14 RITTERF.N.(1970) Chronic suppurative otitis media and the pathologic labyrinthine fistula. Laryngoscope 80, 1025-1035 I 5 KOBAYASHI T., SAKURAI T., OKITSU T., YUASA R., KAWASE T., J. & TAKASAKA T. (1989) Labyrinthine fistula caused KUSAKARI by cholesteatoma. Improved bond conduction by trcatrnent. A m . J . Otol. 10, 5-10.
