Ann Otol 88 :1979
TRENDS AND PROFILES IN STAPES SURGERY RICHARD
J.
BELLUCCI,
MD
NEW YORK, NEW YORK
Stapedectomy has become recognized as the procedure of choice in the surgical treatment of clinical otosclerosis. Based on results obtained in stapes surgery performed in 1977, profiles were established for hearing improvement, vertigo, tinnitus, chorda tympani injury and temporary threshold shift of high tones. Tympanometric and stapedial muscle reflex tests in cases of proved clinical otosclerosis also are discussed. The profiles indicate that stapedectomy performed on a regular basis and under ideal conditions is highly successful for the improvement of hearing. The incidence and probable causes of complications are presented and discussed. This study reveals, however, that the number of new patients with otosclerosis has decreased steadily since its peak in 1964. Should the number of surgical cases continue to diminish, it may be impossible for the practicing otologist to maintain sufficient expertise for the performance of an occasional stapedectomy. Also, it may become impossible to provide sufficient experience in otosclerosis surgery for all trainees in otolaryngology.
Fenestration of the horizontal semicircular canal for the restoration of hearing in otosclerosis was meeting considerable patient resistance in the late 195Os. Fortunately, by that time stapes surgery had passed through its developmental stages and was growing in the confidence of otologists. The acceptance of stapes surgery in the early 1960s progressed rapidly and in 1964 (Fig. 1) the peak number of this operation was recorded. Although showing a gradual decrease over the next five years, the number of operations performed yearly remained relatively high. By 1970 the number of cases had diminished to approximately one third done in 1964. This level, between 100200 cases yearly, has been maintained until the present time. Some important trends were disclosed when the cases performed in 1977 were studied. The number of new patients with otosclerosis had decreased and the majority of stapedectomies had been performed on the second ear. I had performed the first stapedectomy on the majority (83%) of these patients. In second ear cases, an average of five years elapsed between operations. The second ear seldom had been operated upon before a period of two years. It was noted further that patients having the first stapedectomy in 1977 were younger in age than previous-
ly. Of the 40 patients having the first stapedectomy in 1977, 73% were younger than 35 years of age, and had been having difficulty in hearing for an average of three years. In contrast, 100 patients having had stapedectomy in 1964 were found to be an average of 48 years of age and had noticed a hearing loss for an average of 11 years (Table 1). These statistics suggest that the backlog of older otosclerotic patients has been depleted and the new patients seen today are younger and have clinical symptoms for a shorter length of time. Some older patients with otosclerosis are seen who have not had a previous otological study or have been reluctant to have surgery. Four revisions were performed in 1977 because of regression in hearing. In all four cases the loss of hearing was due to displacement of the polyethylene tube prosthesis which was employed between 1958 and 1961.1 Scar tissue had drawn the tube toward the promontory and thus contact with the footplate was lost. There were five cases which exhibited a conductive hearing loss and had a normal appearing tympanic membrane. The preoperative diagnosis of otosclerosis was proved inaccurate as an ossic-
From the Department of Otolaryngology. The New York Medical College, Manhattan Eye, Ear and Throat Hospital, New York, New York. Presented at the meeting of the American Otological Society, Iric., Los Angeles, California. March 31-April 1. 1979.
708
Downloaded from aor.sagepub.com at East Carolina University on July 14, 2015
709
STAPES SURGERY
400 0,
,
, 0-
-.----"',
300
,, ,, ,, , \
200
. ---, -
\ \
,, "
, ~;A-, ,
\
\ '
......
\"
)('
100
111113
114
116
lIlI
117
1111
611
70
71
.......
72
-- ........
73
,0-
'-"-----"" '0
74
15
76
77
Fig. 1. Trend of stapes surgery.
ular abnormality was found in five. In two cases there was a congenital fixation of the malleus where the head was fixed anteriorly to the anterior tympanic spine and superiorly to the tegmen tympani. The manubrium was absent in the other case. In the third case, congenital ossicular fixation of the stapes footplate was seen in a young girl ten years of age. Ossicular discontinuity was found in two cases. In one the incus was displaced as a result of trauma and the other had postinfectious lenticular process erosion. All cases had clinical and audiometric findings similar to those with otosclerosis, but in four of the five cases the hearing loss was unilateral (Table 2). The volume of surgical cases has become stabilized at approximately 100 cases yearly in a practice limited to otology. This number would provide a surgical case load which averages about 2-3 stapedectomies per week. As most new patients are young, it is possible to conclude that this trend represents the rate of currently maturing otosclerosis. Furthermore, a large number of second ear stapedectomies are now being done and fewer will be available in the future. This is further reason to predict that the decrease in the number of stapedectomies may continue. PROFILE OF HEARING IMPROVEMENT
In general, stapedectomy using fat
and wire protheses has been found to improve hearing in 96% of cases (Table 3). Among these cases, the postoperative air conduction hearing was improved in 22% to a level above the preoperative bone conduction. A clear physiological explanation, however, for overclosure of the air-bone gap has not been established. In most cases (63%), the air-bone gap was closed to within 10 dB and in 15% the hearing level was improved but did not approach to within 10 dB of the preoperative bone conduction." In two cases there was no postoperative improvement, and in both cases the conductive hearing loss was unilateral. The postoperative bone conduction and discrimination for speech remained unchanged. The reason for failure to obTABLE 1. SOURCES AND CHARACTERISTICS OF SURGICAL CASES Total cases Total fat wire stapedectomy First Ear Total Younger than 35 years Older than 35 years Second Ear Total My patients Other surgeons Revisions Conductive loss, not otosclerosis
Downloaded from aor.sagepub.com at East Carolina University on July 14, 2015
40 29 11 54 45 9
103 94 91% 43% 73% 27% 57% 83% 17% 4 4% 5
5%
710
RICHARD ]. BELLUCCI
TABLE 2. ANALYSIS OF NONOTOSCLEROTIC CONDUCTIVE HEARING LOSS Total cases Conductive loss, not otosclerosis Congenital ossicular fixation Malleus head fixation Malleus malformation Stapes footplate fixation Ossicular discontinuity Traumatic Postinfections
tain the expected hearing improvement is not clear as there were no unusual findings at surgery and the procedure was performed without problems. The two patients did not experience any vertigo or unusual symptoms in the postoperative period. The one total cochlear loss could not be explained by middle ear findings or by the events during the operation. On rare occasions the inner ear reacts unpredictably and serous labyrinthitis with hydrops develops which destroys the cochlear function. Vestibular responses in this case of complete cochlear loss of function remained present but diminished by 24% when compared to the unoperated ear indicating that the labyrinthitis also involves the vestibular organs. PROFILE OF TEMPORARY THRESHOLD SHIFI'
Varying degrees of temporary loss of hearing between 2000 to 8000 Hz occurred in 33% of cases (Table 4). Applying the burr to the oval window has been considered the most important contributing factor in this complication. Of the 94 stapedectomies, 69% had a blue, thin stapes footplate without narrowing of the oval window niche (Table 5). The burr was not used in these cases. In 29 cases the burr was required but only in 9 was it applied directly to the
103
5
5% 60% 33% 33% 33% 40% 50% 50%
3 I 1 1
2 1 1
footplate of the stapes. In these nine cases the footplate was too thick to be divided with a needle and the footplate was extracted using techniques previously described." Among these, a very thick footplate was found in six cases but the stapediovestibular joint was identifiable. In only three cases was the footplate found to be thick and the stapediovestibular joint space obliterated. In 20 cases the burr was used to enlarge a narrow oval window niche but application of the burr to the footplate of the stapes was not necessary. In 13 cases there was no clearly identifiable cause for the temporary high tone threshold shift (Table 4). Of the 29 cases which required the use of a burr high tone temporary threshold shift was demonstrated in only 5 cases. Significant bleeding into the vestibule occurred in 15 cases but only 4 cases showed a temporary threshold shift. This unfavorable labyrinth response was found to occur most often when perilymph was aspirated from the vestibule in the course of footplate extraction. Of the 11 cases in which a significant amount of perilymph was lost, 9 cases (82%) demonstrated temporary high tone threshold shift (Table 4). PROFILE FOR TINNITUS
Most patients having a temporary
TABLE 3. ANALYSIS OF HEARING RESULTS AFTER STAPEDECTOMY Total fat wire stapedectomy Hearing improved Overclosed AB gap Closed AB gap (BC - 10 dB) Improved No improvement Cochlear loss
94 91
20 57 14
AB - Air-bone; Be - Bone conduction.
Downloaded from aor.sagepub.com at East Carolina University on July 14, 2015
96% 22%
63% 15% 2 1
2%
1%
711
STAPES SURGERY
TABLE 4. ANALYSIS OF CAUSATIVE FACTORS IN TEMPORARY HIGH TONE THRESHOLD SHIFT No. of Pt.
29 11 15 94
High Tone Shift
Without cause Required drilling Loss of perilymph Bleeding into vestibule Total cases
13 5 9 4 31
high tone threshold shift complained of loss of discrimination and distortion of speech early in the postoperative period. Some complained also of high pitched tinnitus but the shift and the tinnitus were not always related. The majority of cases showed slow recovery of the high tone loss in the weeks following the surgery. Very few, however, were observed to recover completely, and consistently a residual loss remained. Tinnitus which appeared as a result of the surgery rarely subsided with the passage of time (Table 6). Tinnitus which was present before surgery remained unchanged following stapedectomy in most cases. In 35% the level of tinnitus decreased or disappeared completely and in 7% the tinnitus became more intense after surgery. Tinnitus which became more intense after surgery was found most often associated with a high tone hearing loss. PROFILE FOR IN JURY TO CHORDA lYMPANI
The chorda was preserved in the majority of cases (71%). In 17 cases the chorda was sacrificed but only ten patients complained of disturbance in taste. Stretching or tearing of the sheath of the nerve was considered the same as having severed the nerve. Very few of the patients whose chorda tympani was traumatized or severed comTABLE 5. APPLICATION OF BURR REQUIRED BY DISTRIBUTION AND CHARACTERISTICS OF OVAL WINDOW OTOSCLEROSIS Total fat wire stapedectomy No drilling, blue footplate Drilling required Solid footplate Biscuit Narrow oval window
3 6 20
94 65 69% 29 31% 11% 20% 69%
TABLE 6. ANALYSIS OF TINNITUS AND INJURY TO CHORDA TYMPANI Total fat wire stapedectomy Tinnitus lessened Tinnitus worse No change Chorda preserved Chorda sacrificed Disturbance in taste
94 33 7 54 67 17 10
35% 7% 57% 71% 18% 11%
plained of taste disturbance for a long period of time (Table 6). Some complained of a bitter or metallic taste on the tongue on the side corresponding to the injured nerve. Soon, however, there were no further complaints and the patient made some type of adjustment which is not clear. PROFILE OF VERTIGO
Vertigo following stapedectomy should be an uncommon complaint. However, when it does occur it indicates that some surgical trauma to the labyrinth has taken place. Only 13 of 94 cases ( 14%) experienced vertigo for more than one day. The most common causative agent was found to be excessive aspiration of perilymph (Table 7). Bleeding into the vestibule seemed a less important factor in causing postoperative vertigo. Aspiration of blood from the oval window usually is preceded by the perilymph because the blood is much heavier than the perilymphatic fluid. It seems preferable, therefore, to allow smsII amounts of blood to remain in the vestibule as blood seems to cause little labyrinthine reaction. Of the 94 stapedectomies 16 had vertigo lasting only a few hours. This brief period of vertigo probably may not have been of labvrinthine origin and rather was due to the relatively large doses of preoperative medication required in stapedectomies done under local anesthesia. Most TABLE 7. INCIDENCE AND ANALYSIS OF POSTOPERATIVE VERTIGO
No. of Pt.
11 Loss of perilymph 15 Bleeding into vestibule 94 Total cases
Downloaded from aor.sagepub.com at East Carolina University on July 14, 2015
Less More Than Than One One Day Day None
16
10
1
3 13
65
712
RICHARD ]. BELLUCCI
TABLE 8. TYMPANOMETRIC RESPONSES IN OTOSCLEROSIS WITH PROVED STAPEDIAL FOOTPLATE FIXATION Total cases AS curve A curve Cor B curve
64
26 32 6
40% 50% 10%
cases (69% ) experienced no vertigo whatsoever after stapedectomy. PROFILE OF TYMPANOMETRY
Tympanometry most often revealed a normal A type curve (50%) in patients tested. The anticipated AS type curve typical for otosclerosis was obtained in 40%. In 10% of cases types C or B curves were seen but at surgery there were no clear explanations for these responses (Table 8). The AS type curve, indicating limitation of motion of the tympanic membrane is the anticipated response in otosclerosis. The high percentage of normal type A configuration found in clinically proved otosclerosis with stapedial fixation is difficult to explain. The fixed stapes should prohibit normal mobility of the ossicular chain and tvmpanic membrane. In the cases with A type responses, however, the stapes was found to be sufficiently fixed at the footplate in all cases to cause loss of hearing. Factors related to ossicular movement other than otosclerosis may permit partial mobility of the tympanic membrane and may account for the high number of normal A type responses. As an isolated test the tympanogram was considered to be unreliable in diagnosis of stapes fixation due to otosclerosis. When related to other tests, however, it does have limited clinical value. The stapedial muscle reflex was found to be more reliable as an indication of footplate fixation. The contralateral reflex was absent in 84% of cases (Table 9), and a response was obtained in 16%. As the stapes is fixed in the oval window, contraction of the stapedial muscle will not cause motion in the ossicular chain and tympanic membrane. The reflex therefore will be absent in the tympanogram. Confusing results have been obtained since a reflex was found to be present in 16% of cases with clinically proved fixation of the stapes by otosclerosis.
TABLE 9. CONTRALATERAL MUSCLE REFLEXES IN STAPEDIAL FOOTPLATE FIXATION Total cases Response absent Response present
64
54 10
84% 16%
Theoretically, it is possible to obtain a weak positive reflex if the stapes crura are thin and pliable permitting some motion in the tympanic membrane. A reflex may also be present in early otosclerosis with minimal fixation of the stapes footplate. As the otosclerotic lesion cannot be visualized directly, the preoperative diagnosis is made by the process of elimination. The stapedial reflex becomes of greater value in the differential diagnosis of a conductive hearing loss of unclear etiology. DISCUSSION AND CONCLUSIONS
Stapedectomy has become accepted and recognized as a highly efficient operative procedure. It is considered the procedure of choice in the surgical treatment of clinical otosclerosis. The surgical procedure is short in duration, definitive, challenging, and highly successful as 96% of patients experience improved hearing. After developing improved surgical skills and techniques some of the complications which at first seemed inherently associated with this operation became less frequent. Postoperative vertigo provides a good example. For a period of time following the introduction of stapedectomy, vertigo of varying degrees was experienced by almost every postoperative patient. Loss of equilibrium was considered a regular and usual labyrinthine response to this operation. With the improvement of instrumentation and surgical techniques vertigo became less frequently seen, and today postoperative vertigo has been practically eliminated. When it occurs, however, vertigo generally indicates that the vestibular structures have received some type of surgical trauma. Direct invasion of the vestibule by instruments and the excessive aspiration of perilymphatic fluid are the most frequent causes. Consequently, extreme care should be taken to avoid the application of the aspirating tube too close to the oval window and to extract the
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STAPES SURGERY footplate only after complete hemostasis has been achieved. 2 A temporary high tone threshold shift following stapedectomy was observed in one third of the cases. This unfavorable cochlear response was most frequently seen after perilymph had been aspirated from the inner ear. At one time the use of the burr in the oval window was thought to be the most important cause for this response. The statistics herein indicate that loss of perilymph is the basic problem and not the trauma of the burr. In reality, stapedectomy does not seem to have a decisive effect on tinnitus in the majority of cases. In a few cases the tinnitus was identified and in 24% the tinnitus was diminished or completely relieved. Injury to the chorda tympani rarely creates any complaints which are of long duration. Some form of compensation must take place which helps the patient adjust to the loss of taste. Occasionally patients will complain of a metallic taste on the side of the injured chorda tympani nerve. In time most patients seem to compensate for the loss as the complaint is no longer mentioned. Tympanometry was found to contribute little in the differential diagnosis of otosclerosis. The stapedial muscle reflex, however, offers useful information in cases with complicated clinical findings. As 10% of the cases with proved stapedial footplate fixation had an identifiable reflex, this test therefore only can be considered of value with respect to all other clinical tests and physical findings. The most significant conclusion of this studv is the apparent trend toward a steady decline in the number of patients with clinical otosclerosis resulting
713
in fewer stapedectomies. Insufficient surgical cases will have a serious effect on the practice and training of otologists. The profiles of stapedectomy reveal that consistently good results can only be produced by experienced surgeons with well maintained equipment and competent assistance in the operating room. The shortage of surgical cases makes it difficult to keep the operating room staff and equipment in optimum condition. The practicing otologists who see only a few cases of otosclerosis yearly also may find it difficult to maintain sufficient personal confidence to perform an occasional stapedectomy. The inner ear is a delicate and labile structure which does not accept even the slightest trauma without a response. A small error, such as the aspiration of excessive perilymphatic fluid may be reflected in an unfavorable postoperative result. Furthermore, an occasional complete cochlear loss following a stapedectomy which was considered flawless in every respect has occurred even in the hands of experienced otologists. As otosclerosis is not present in laboratory animals, the aspiring otologist must obtain his training in the operating room under the careful supervision of an experienced instructor. Should the number of surgical cases continue to diminish, it may be impossible to provide sufficient experience in otosclerosis surgery to all trainees in this specialty. If this situation prevails, experience in stapes surgery may become available to relatively few individuals at major training centers or in preceptorship programs under direction of otologists who perform stapes surgery on a regular basis.
REFERENCES 1. Bellucci RJ: Subluxation and depression of stapes footplate. Arch Otolaryngol 85: 182183, 1967 2. Bellucci RJ: Survey of stapes surgery.
Five year study. Arch Otolaryngol 89:408411, 1969 3. Bellucci RJ: "How I do it" - Footplate extraction in stapedectomy. Laryngoscope 88: 701-706, 1978
REPRINTS - Richard J. Bellucci, MD, Dept. of Otolaryngology, The New York Medical College, Manhattan Eye and Throat Hospital, New York, NY 10021.
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TRENDS AND PROFILES IN STAPES SURGERY RICHARD
J.
BELLUCCI,
MD
NEW YORK, NEW YORK
Stapedectomy has become recognized as the procedure of choice in the surgical treatment of clinical otosclerosis. Based on results obtained in stapes surgery performed in 1977, profiles were established for hearing improvement, vertigo, tinnitus, chorda tympani injury and temporary threshold shift of high tones. Tympanometric and stapedial muscle reflex tests in cases of proved clinical otosclerosis also are discussed. The profiles indicate that stapedectomy performed on a regular basis and under ideal conditions is highly successful for the improvement of hearing. The incidence and probable causes of complications are presented and discussed. This study reveals, however, that the number of new patients with otosclerosis has decreased steadily since its peak in 1964. Should the number of surgical cases continue to diminish, it may be impossible for the practicing otologist to maintain sufficient expertise for the performance of an occasional stapedectomy. Also, it may become impossible to provide sufficient experience in otosclerosis surgery for all trainees in otolaryngology.
Fenestration of the horizontal semicircular canal for the restoration of hearing in otosclerosis was meeting considerable patient resistance in the late 195Os. Fortunately, by that time stapes surgery had passed through its developmental stages and was growing in the confidence of otologists. The acceptance of stapes surgery in the early 1960s progressed rapidly and in 1964 (Fig. 1) the peak number of this operation was recorded. Although showing a gradual decrease over the next five years, the number of operations performed yearly remained relatively high. By 1970 the number of cases had diminished to approximately one third done in 1964. This level, between 100200 cases yearly, has been maintained until the present time. Some important trends were disclosed when the cases performed in 1977 were studied. The number of new patients with otosclerosis had decreased and the majority of stapedectomies had been performed on the second ear. I had performed the first stapedectomy on the majority (83%) of these patients. In second ear cases, an average of five years elapsed between operations. The second ear seldom had been operated upon before a period of two years. It was noted further that patients having the first stapedectomy in 1977 were younger in age than previous-
ly. Of the 40 patients having the first stapedectomy in 1977, 73% were younger than 35 years of age, and had been having difficulty in hearing for an average of three years. In contrast, 100 patients having had stapedectomy in 1964 were found to be an average of 48 years of age and had noticed a hearing loss for an average of 11 years (Table 1). These statistics suggest that the backlog of older otosclerotic patients has been depleted and the new patients seen today are younger and have clinical symptoms for a shorter length of time. Some older patients with otosclerosis are seen who have not had a previous otological study or have been reluctant to have surgery. Four revisions were performed in 1977 because of regression in hearing. In all four cases the loss of hearing was due to displacement of the polyethylene tube prosthesis which was employed between 1958 and 1961.1 Scar tissue had drawn the tube toward the promontory and thus contact with the footplate was lost. There were five cases which exhibited a conductive hearing loss and had a normal appearing tympanic membrane. The preoperative diagnosis of otosclerosis was proved inaccurate as an ossic-
From the Department of Otolaryngology. The New York Medical College, Manhattan Eye, Ear and Throat Hospital, New York, New York. Presented at the meeting of the American Otological Society, Iric., Los Angeles, California. March 31-April 1. 1979.
708
Downloaded from aor.sagepub.com at East Carolina University on July 14, 2015
709
STAPES SURGERY
400 0,
,
, 0-
-.----"',
300
,, ,, ,, , \
200
. ---, -
\ \
,, "
, ~;A-, ,
\
\ '
......
\"
)('
100
111113
114
116
lIlI
117
1111
611
70
71
.......
72
-- ........
73
,0-
'-"-----"" '0
74
15
76
77
Fig. 1. Trend of stapes surgery.
ular abnormality was found in five. In two cases there was a congenital fixation of the malleus where the head was fixed anteriorly to the anterior tympanic spine and superiorly to the tegmen tympani. The manubrium was absent in the other case. In the third case, congenital ossicular fixation of the stapes footplate was seen in a young girl ten years of age. Ossicular discontinuity was found in two cases. In one the incus was displaced as a result of trauma and the other had postinfectious lenticular process erosion. All cases had clinical and audiometric findings similar to those with otosclerosis, but in four of the five cases the hearing loss was unilateral (Table 2). The volume of surgical cases has become stabilized at approximately 100 cases yearly in a practice limited to otology. This number would provide a surgical case load which averages about 2-3 stapedectomies per week. As most new patients are young, it is possible to conclude that this trend represents the rate of currently maturing otosclerosis. Furthermore, a large number of second ear stapedectomies are now being done and fewer will be available in the future. This is further reason to predict that the decrease in the number of stapedectomies may continue. PROFILE OF HEARING IMPROVEMENT
In general, stapedectomy using fat
and wire protheses has been found to improve hearing in 96% of cases (Table 3). Among these cases, the postoperative air conduction hearing was improved in 22% to a level above the preoperative bone conduction. A clear physiological explanation, however, for overclosure of the air-bone gap has not been established. In most cases (63%), the air-bone gap was closed to within 10 dB and in 15% the hearing level was improved but did not approach to within 10 dB of the preoperative bone conduction." In two cases there was no postoperative improvement, and in both cases the conductive hearing loss was unilateral. The postoperative bone conduction and discrimination for speech remained unchanged. The reason for failure to obTABLE 1. SOURCES AND CHARACTERISTICS OF SURGICAL CASES Total cases Total fat wire stapedectomy First Ear Total Younger than 35 years Older than 35 years Second Ear Total My patients Other surgeons Revisions Conductive loss, not otosclerosis
Downloaded from aor.sagepub.com at East Carolina University on July 14, 2015
40 29 11 54 45 9
103 94 91% 43% 73% 27% 57% 83% 17% 4 4% 5
5%
710
RICHARD ]. BELLUCCI
TABLE 2. ANALYSIS OF NONOTOSCLEROTIC CONDUCTIVE HEARING LOSS Total cases Conductive loss, not otosclerosis Congenital ossicular fixation Malleus head fixation Malleus malformation Stapes footplate fixation Ossicular discontinuity Traumatic Postinfections
tain the expected hearing improvement is not clear as there were no unusual findings at surgery and the procedure was performed without problems. The two patients did not experience any vertigo or unusual symptoms in the postoperative period. The one total cochlear loss could not be explained by middle ear findings or by the events during the operation. On rare occasions the inner ear reacts unpredictably and serous labyrinthitis with hydrops develops which destroys the cochlear function. Vestibular responses in this case of complete cochlear loss of function remained present but diminished by 24% when compared to the unoperated ear indicating that the labyrinthitis also involves the vestibular organs. PROFILE OF TEMPORARY THRESHOLD SHIFI'
Varying degrees of temporary loss of hearing between 2000 to 8000 Hz occurred in 33% of cases (Table 4). Applying the burr to the oval window has been considered the most important contributing factor in this complication. Of the 94 stapedectomies, 69% had a blue, thin stapes footplate without narrowing of the oval window niche (Table 5). The burr was not used in these cases. In 29 cases the burr was required but only in 9 was it applied directly to the
103
5
5% 60% 33% 33% 33% 40% 50% 50%
3 I 1 1
2 1 1
footplate of the stapes. In these nine cases the footplate was too thick to be divided with a needle and the footplate was extracted using techniques previously described." Among these, a very thick footplate was found in six cases but the stapediovestibular joint was identifiable. In only three cases was the footplate found to be thick and the stapediovestibular joint space obliterated. In 20 cases the burr was used to enlarge a narrow oval window niche but application of the burr to the footplate of the stapes was not necessary. In 13 cases there was no clearly identifiable cause for the temporary high tone threshold shift (Table 4). Of the 29 cases which required the use of a burr high tone temporary threshold shift was demonstrated in only 5 cases. Significant bleeding into the vestibule occurred in 15 cases but only 4 cases showed a temporary threshold shift. This unfavorable labyrinth response was found to occur most often when perilymph was aspirated from the vestibule in the course of footplate extraction. Of the 11 cases in which a significant amount of perilymph was lost, 9 cases (82%) demonstrated temporary high tone threshold shift (Table 4). PROFILE FOR TINNITUS
Most patients having a temporary
TABLE 3. ANALYSIS OF HEARING RESULTS AFTER STAPEDECTOMY Total fat wire stapedectomy Hearing improved Overclosed AB gap Closed AB gap (BC - 10 dB) Improved No improvement Cochlear loss
94 91
20 57 14
AB - Air-bone; Be - Bone conduction.
Downloaded from aor.sagepub.com at East Carolina University on July 14, 2015
96% 22%
63% 15% 2 1
2%
1%
711
STAPES SURGERY
TABLE 4. ANALYSIS OF CAUSATIVE FACTORS IN TEMPORARY HIGH TONE THRESHOLD SHIFT No. of Pt.
29 11 15 94
High Tone Shift
Without cause Required drilling Loss of perilymph Bleeding into vestibule Total cases
13 5 9 4 31
high tone threshold shift complained of loss of discrimination and distortion of speech early in the postoperative period. Some complained also of high pitched tinnitus but the shift and the tinnitus were not always related. The majority of cases showed slow recovery of the high tone loss in the weeks following the surgery. Very few, however, were observed to recover completely, and consistently a residual loss remained. Tinnitus which appeared as a result of the surgery rarely subsided with the passage of time (Table 6). Tinnitus which was present before surgery remained unchanged following stapedectomy in most cases. In 35% the level of tinnitus decreased or disappeared completely and in 7% the tinnitus became more intense after surgery. Tinnitus which became more intense after surgery was found most often associated with a high tone hearing loss. PROFILE FOR IN JURY TO CHORDA lYMPANI
The chorda was preserved in the majority of cases (71%). In 17 cases the chorda was sacrificed but only ten patients complained of disturbance in taste. Stretching or tearing of the sheath of the nerve was considered the same as having severed the nerve. Very few of the patients whose chorda tympani was traumatized or severed comTABLE 5. APPLICATION OF BURR REQUIRED BY DISTRIBUTION AND CHARACTERISTICS OF OVAL WINDOW OTOSCLEROSIS Total fat wire stapedectomy No drilling, blue footplate Drilling required Solid footplate Biscuit Narrow oval window
3 6 20
94 65 69% 29 31% 11% 20% 69%
TABLE 6. ANALYSIS OF TINNITUS AND INJURY TO CHORDA TYMPANI Total fat wire stapedectomy Tinnitus lessened Tinnitus worse No change Chorda preserved Chorda sacrificed Disturbance in taste
94 33 7 54 67 17 10
35% 7% 57% 71% 18% 11%
plained of taste disturbance for a long period of time (Table 6). Some complained of a bitter or metallic taste on the tongue on the side corresponding to the injured nerve. Soon, however, there were no further complaints and the patient made some type of adjustment which is not clear. PROFILE OF VERTIGO
Vertigo following stapedectomy should be an uncommon complaint. However, when it does occur it indicates that some surgical trauma to the labyrinth has taken place. Only 13 of 94 cases ( 14%) experienced vertigo for more than one day. The most common causative agent was found to be excessive aspiration of perilymph (Table 7). Bleeding into the vestibule seemed a less important factor in causing postoperative vertigo. Aspiration of blood from the oval window usually is preceded by the perilymph because the blood is much heavier than the perilymphatic fluid. It seems preferable, therefore, to allow smsII amounts of blood to remain in the vestibule as blood seems to cause little labyrinthine reaction. Of the 94 stapedectomies 16 had vertigo lasting only a few hours. This brief period of vertigo probably may not have been of labvrinthine origin and rather was due to the relatively large doses of preoperative medication required in stapedectomies done under local anesthesia. Most TABLE 7. INCIDENCE AND ANALYSIS OF POSTOPERATIVE VERTIGO
No. of Pt.
11 Loss of perilymph 15 Bleeding into vestibule 94 Total cases
Downloaded from aor.sagepub.com at East Carolina University on July 14, 2015
Less More Than Than One One Day Day None
16
10
1
3 13
65
712
RICHARD ]. BELLUCCI
TABLE 8. TYMPANOMETRIC RESPONSES IN OTOSCLEROSIS WITH PROVED STAPEDIAL FOOTPLATE FIXATION Total cases AS curve A curve Cor B curve
64
26 32 6
40% 50% 10%
cases (69% ) experienced no vertigo whatsoever after stapedectomy. PROFILE OF TYMPANOMETRY
Tympanometry most often revealed a normal A type curve (50%) in patients tested. The anticipated AS type curve typical for otosclerosis was obtained in 40%. In 10% of cases types C or B curves were seen but at surgery there were no clear explanations for these responses (Table 8). The AS type curve, indicating limitation of motion of the tympanic membrane is the anticipated response in otosclerosis. The high percentage of normal type A configuration found in clinically proved otosclerosis with stapedial fixation is difficult to explain. The fixed stapes should prohibit normal mobility of the ossicular chain and tvmpanic membrane. In the cases with A type responses, however, the stapes was found to be sufficiently fixed at the footplate in all cases to cause loss of hearing. Factors related to ossicular movement other than otosclerosis may permit partial mobility of the tympanic membrane and may account for the high number of normal A type responses. As an isolated test the tympanogram was considered to be unreliable in diagnosis of stapes fixation due to otosclerosis. When related to other tests, however, it does have limited clinical value. The stapedial muscle reflex was found to be more reliable as an indication of footplate fixation. The contralateral reflex was absent in 84% of cases (Table 9), and a response was obtained in 16%. As the stapes is fixed in the oval window, contraction of the stapedial muscle will not cause motion in the ossicular chain and tympanic membrane. The reflex therefore will be absent in the tympanogram. Confusing results have been obtained since a reflex was found to be present in 16% of cases with clinically proved fixation of the stapes by otosclerosis.
TABLE 9. CONTRALATERAL MUSCLE REFLEXES IN STAPEDIAL FOOTPLATE FIXATION Total cases Response absent Response present
64
54 10
84% 16%
Theoretically, it is possible to obtain a weak positive reflex if the stapes crura are thin and pliable permitting some motion in the tympanic membrane. A reflex may also be present in early otosclerosis with minimal fixation of the stapes footplate. As the otosclerotic lesion cannot be visualized directly, the preoperative diagnosis is made by the process of elimination. The stapedial reflex becomes of greater value in the differential diagnosis of a conductive hearing loss of unclear etiology. DISCUSSION AND CONCLUSIONS
Stapedectomy has become accepted and recognized as a highly efficient operative procedure. It is considered the procedure of choice in the surgical treatment of clinical otosclerosis. The surgical procedure is short in duration, definitive, challenging, and highly successful as 96% of patients experience improved hearing. After developing improved surgical skills and techniques some of the complications which at first seemed inherently associated with this operation became less frequent. Postoperative vertigo provides a good example. For a period of time following the introduction of stapedectomy, vertigo of varying degrees was experienced by almost every postoperative patient. Loss of equilibrium was considered a regular and usual labyrinthine response to this operation. With the improvement of instrumentation and surgical techniques vertigo became less frequently seen, and today postoperative vertigo has been practically eliminated. When it occurs, however, vertigo generally indicates that the vestibular structures have received some type of surgical trauma. Direct invasion of the vestibule by instruments and the excessive aspiration of perilymphatic fluid are the most frequent causes. Consequently, extreme care should be taken to avoid the application of the aspirating tube too close to the oval window and to extract the
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STAPES SURGERY footplate only after complete hemostasis has been achieved. 2 A temporary high tone threshold shift following stapedectomy was observed in one third of the cases. This unfavorable cochlear response was most frequently seen after perilymph had been aspirated from the inner ear. At one time the use of the burr in the oval window was thought to be the most important cause for this response. The statistics herein indicate that loss of perilymph is the basic problem and not the trauma of the burr. In reality, stapedectomy does not seem to have a decisive effect on tinnitus in the majority of cases. In a few cases the tinnitus was identified and in 24% the tinnitus was diminished or completely relieved. Injury to the chorda tympani rarely creates any complaints which are of long duration. Some form of compensation must take place which helps the patient adjust to the loss of taste. Occasionally patients will complain of a metallic taste on the side of the injured chorda tympani nerve. In time most patients seem to compensate for the loss as the complaint is no longer mentioned. Tympanometry was found to contribute little in the differential diagnosis of otosclerosis. The stapedial muscle reflex, however, offers useful information in cases with complicated clinical findings. As 10% of the cases with proved stapedial footplate fixation had an identifiable reflex, this test therefore only can be considered of value with respect to all other clinical tests and physical findings. The most significant conclusion of this studv is the apparent trend toward a steady decline in the number of patients with clinical otosclerosis resulting
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in fewer stapedectomies. Insufficient surgical cases will have a serious effect on the practice and training of otologists. The profiles of stapedectomy reveal that consistently good results can only be produced by experienced surgeons with well maintained equipment and competent assistance in the operating room. The shortage of surgical cases makes it difficult to keep the operating room staff and equipment in optimum condition. The practicing otologists who see only a few cases of otosclerosis yearly also may find it difficult to maintain sufficient personal confidence to perform an occasional stapedectomy. The inner ear is a delicate and labile structure which does not accept even the slightest trauma without a response. A small error, such as the aspiration of excessive perilymphatic fluid may be reflected in an unfavorable postoperative result. Furthermore, an occasional complete cochlear loss following a stapedectomy which was considered flawless in every respect has occurred even in the hands of experienced otologists. As otosclerosis is not present in laboratory animals, the aspiring otologist must obtain his training in the operating room under the careful supervision of an experienced instructor. Should the number of surgical cases continue to diminish, it may be impossible to provide sufficient experience in otosclerosis surgery to all trainees in this specialty. If this situation prevails, experience in stapes surgery may become available to relatively few individuals at major training centers or in preceptorship programs under direction of otologists who perform stapes surgery on a regular basis.
REFERENCES 1. Bellucci RJ: Subluxation and depression of stapes footplate. Arch Otolaryngol 85: 182183, 1967 2. Bellucci RJ: Survey of stapes surgery.
Five year study. Arch Otolaryngol 89:408411, 1969 3. Bellucci RJ: "How I do it" - Footplate extraction in stapedectomy. Laryngoscope 88: 701-706, 1978
REPRINTS - Richard J. Bellucci, MD, Dept. of Otolaryngology, The New York Medical College, Manhattan Eye and Throat Hospital, New York, NY 10021.
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