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Endolymphatic mastoid shunt versus endolymphatic sac decompression for Ménière’s disease
Otolaryngology–Head and Neck Surgery (2007) 136, 415-421
ORIGINAL RESEARCH
Endolymphatic mastoid shunt versus endolymphatic sac decompression for Ménière’s disease George M. Brinson, MD, Douglas A. Chen, MD, and Moisés A. Arriaga, MD, Wilmington, NC; and Pittsburgh, PA OBJECTIVE: This study compares the efficacy of endolymphatic mastoid shunt (EMS) versus endolymphatic sac decompression (ESD) without sac incision for the treatment of Ménière’s disease. STUDY DESIGN AND SETTING: The AAO-HNS Guidelines for the Diagnosis and Evaluation of Therapy in Ménière’s disease were used to retrospectively identify suitable candidates for the study. All patients who failed medical management and underwent either endolymphatic-mastoid shunt (EMS) (n ⫽ 88) or endolymphatic sac decompression (ESD) (n ⫽ 108) were selected for review using the AAO-HNS guidelines. The study was carried out at a tertiary care neurotology private practice. RESULTS: EMS and ESD were equally effective in reducing the incidence and severity of vertigo attacks with significant improvement in 67 percent and 66 percent of patients, respectively. CONCLUSION: Both EMS and ESD are effective, nondestructive alternatives for patients who have failed medical management of Ménière’s disease with similar long-term hearing outcomes. SIGNIFICANCE: This is the only study within the same institution using AAO-HNS guidelines comparing EMS versus ESD. © 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.
1927.1 An extensive variety of procedures have since been described involving simple decompression, endolymphatic subarachnoid drainage, endolymphatic mastoid drainage, and, in some cases, removal of the extraosseous portion of the sac.2 Although some physicians claim remarkable success, others doubt the efficacy of sac surgery altogether. Our current understanding of the disease has recently been reviewed by Paparella and Djalilian.3 Multiple theories attempt to explain the mechanism by which ESS affects Ménière’s disease and include decompression of a tightly bound endolymphatic sac, neovascularization of the perisaccular region, passive diffusion of endolymph, and the creation of an osmotic gradient between the sac and the endolymph.4 Even though ESS has been surrounded by controversy, it still remains the most common surgical therapy carried out for the treatment of Ménière’s disease.5 The goal of this study is to compare the efficacy of endolymphatic sac decompression (ESD) with endolymphatic-mastoid shunt (EMS).
W
hen patients fail medical management of Ménière’s disease, surgical intervention is indicated to stabilize the disease. Options include endolymphatic sac surgery (ESS), transtympanic injection of gentamycin, labyrinthectomy, and vestibular nerve section. Endolymphatic sac enhancement is appealing to patients and surgeons because it is nondestructive and does not require a craniotomy. Endolymphatic sac surgery for the treatment of Ménière’s disease has been the subject of much discussion and controversy since it was first described by Portmann in
METHODS
From the Wilmington ENT, NC (Dr Brinson), and Pittsburgh Ear Associates, Allegheny General Hospital, PA (Drs Chen and Arriaga). Presented at the American Academy of Otolaryngology–Head and Neck Surgery, New York, NY, September 19-22, 2004.
Reprint requests: Douglas A. Chen, MD, Pittsburgh Ear Associates, Suite 402, Pittsburgh, PA 15212. E-mail address: [email protected].
All patients that underwent ESS at Pittsburgh Ear Associates between the years of 1992 and 2003 were identified through a retrospective chart review. The procedures were carried out by two different surgeons. One surgeon prefers EMS (D.A.C.) for patients with Ménière’s whereas the other surgeon prefers ESD (M.A.A.). All patients had failed medical therapy consisting of dietary salt and caffeine restriction, diuretics, subcutaneous histamine, and vestibular sup-
0194-5998/$32.00 © 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2006.08.031
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pressants. The medical management used by each surgeon pre-and postoperatively was evaluated and did not differ significantly. A total of 108 patients had undergone ESD and 88 patients had undergone EMS. Preoperative data was obtained that included the extent of medical management, frequency of vertigo, extent of hearing loss, and degree of disability. Data was collected through a chart review as well as through a questionnaire, and 1995 AAO criteria were used in all data collection and reporting.6 Patients were diagnosed as having definite, probable, or possible Ménière’s disease. Those patients with possible Ménière’s disease carried the diagnosis of either vestibular or cochlear hydrops. Patients with definite Ménière’s disease were examined independently of those with possible Ménière’s disease. The vast majority of patients with possible Ménière’s disease underwent ESD. Those patients with purely cochlear hydrops were excluded from the study. The effect of surgery on vertigo symptoms was reported using the definition of class as defined by the AAO guidelines.6 The worst preoperative audiogram in the 6-month period before surgery was used as a baseline, and patients were divided into stage of disease based on Academy criteria.6 The worst audiogram in the period 18 to 24 months after surgery was used as the postoperative audiogram. Pure tone average (PTA) at 500 Hz, 1 kHz, 2 kHz, and 4 kHz and speech discrimination scores (SDS) were compared pre and postoperatively. Postoperative hearing was reported as better, worse, or the same based on AAO criteria: a change of 10 db or more in PTA or a change in SDS of 15 percentage points was considered clinically significant. The patient’s pre- and postoperative functional level was determined based on the questionnaire responses (Table 1). The affect of surgery on tinnitus, aural fullness, and overall disease was reported as better, worse, or the same based on questionnaire responses. IRB waiver was granted by our institution.
Surgical Technique ESD. Under general anesthesia, a simple mastoidectomy was carried out. The incus, horizontal canal, posterior canal, and sigmoid sinus were identified. The posterior fossa dura anterior to the sigmoid sinus as well as the most anterior portion of the sigmoid sinus was decompressed until the endolymphatic sac was identified. The sac itself and surrounding dura was then decompressed from the region of dense otic capsule bone superiorly to approximately 5 mm inferior to the sac. Surgicel was then placed between the dura and the remaining bone anteriorly to further decompress the sac and duct. EMS. The endolymphatic sac was approached and identified in the same manner as above. The sigmoid sinus was decompressed when necessary for exposure. The sac was then incised and the lumen identified. A T-shaped silastic shunt was then placed into the lumen itself.
Table 1 Functional Level Scale6 1. 2.
3.
4.
5.
6.
My dizziness has no effect on my activities at all. When I am dizzy I have to stop what I am doing for awhile, but it soon passes and I can resume activities. I continue to work, drive, and engage in any activity I choose without restriction. I have not changed any plans or activities to accommodate my dizziness. When I am dizzy I have to stop what I am doing for awhile, but it does pass and I can resume activities. I continue to work, drive and engage in most activities I choose, but I have had to change some plans and make some allowance for my dizziness. I am able to work, drive, travel, take care of a family, or engage in most essential activities, but I must exert a great deal of effort to do so. I must constantly make adjustments in my activities and budget my energies I am barely making it. I am unable to work, drive, or take care of a family. I am unable to do most of the active things that I used to. Even essential activities must be limited. I am disabled. I have been disabled for 1 year or longer and/or I receive compensation (money) because of my dizziness or balance problems.
Data Analysis Data was analyzed using Student’s t test or 2 analysis when appropriate. A value of P ⬍ 0.05 was considered statistically significant.
RESULTS A total of 196 patients were identified who underwent endolymphatic sac surgery. ESD was carried out on 108 patients and EMS was carried out on 88 patients. Average age was 47 for ESD and 53 for EMS. Questionnaires were returned by 135 (69%): 79 questionnaires in ESD group and 53 questionnaires in EMS group. Average follow-up either by chart review or questionnaire was 31 months for ESD patients and 53 months for EMS patients, the difference explained by the fact that EMS has been carried out since 1992, whereas ESD has essentially only been carried out since 1998. The class effect of the procedure was determined based on a combination of questionnaires and chart review. Numbers for the various outcomes may vary because data in some patients was unavailable. When reporting vertigo class at 18 to 24 months, patients with ⬍18-month follow-up were excluded. Among patients with definite Ménière’s undergoing EMS (n ⫽ 54), vertigo class at 18- to 24-months follow-up was Class A (43%), Class B (24%),
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Endolymphatic mastoid shunt versus endolymphatic . . .
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Table 2 Vertigo control by class and functional level at 18 to 24 months follow-up Control class A B C D E F Pre-op functional level Post-op functional level
EMS-definite (n ⫽ 54) n (%)
ESD-definite (n ⫽ 40) n (%)
ESD-possible (n ⫽ 26) n (%)
23 (43) 13 (24) 2 (4) 4 (7) 2 (4) 11 (20) 4.4 2.5 (follow-up ⫽ 51 months)
13 (33) 13 (33) 5 (13) 1 (3) 2 (5) 6 (15) 4.4 2.7 (follow-up ⫽ 32 months)
10 (38) 6 (23) 4 (15) 1 (4) 4 (15) 1 (4) 3.9 2.3 (follow-up ⫽ 25 months)
EMS, endolymphatic mastoid shunt; ESD, endolymphatic sac decompression.
Class C (4%), Class D (7%), Class E (4%), and Class F (20%) (Table 2). Revision procedures within the 24-month period consisted of vestibular nerve section (n ⫽ 5), transtympanic gentamycin (n ⫽ 4), and labyrinthectomy (n ⫽ 1). Using questionnaire data (n ⫽ 52), this group of patients reported tinnitus improved (38%), unchanged (48%), and worse (14%). Aural fullness was improved in 39 percent, unchanged in 43 percent, and worse in 18 percent When asked how the surgery affected their disease overall, 77 percent were improved, 19 percent were unchanged, and 4 percent were worse. Average functional level preoperatively was 4.2 and average functional level at the time of the questionnaire was 2.5. Patients with Class F outcome were excluded from functional level outcome analysis. Using the chart review within this group of patients (n ⫽ 78), oral steroid use was noted in 24 percent of patients preoperatively and 1 percent of patients postoperatively. Transtympanic dexamethasone was used in 5 percent of patients preoperatively and in 1 percent of patients postoperatively. Among patients with definite Ménière’s who underwent ESD (n ⫽ 40), vertigo control at 18 to 24 months was Class A (33%), Class B (33%), Class C (13%), Class D (3%), Class E (5%), and Class F (15%) (Table 2). Among those patients with Class F outcome, four patients underwent vestibular nerve section and two patients received transtympanic gentamycin. Using questionnaire data (n ⫽ 44), this group of patients reported tinnitus improved (41%), unchanged (45%), and worse (14%). Aural fullness was improved in 45 percent, unchanged in 41 percent, and worse in 14 percent. When asked how the surgery affected their disease overall, 75 percent were improved, 18 percent were unchanged, and 7 percent were worse. Average functional level preoperatively was 4.2 and average functional level at the time of the questionnaire was 2.7. Again, patients with Class F outcome were excluded from functional level outcome analysis. Using the chart review from this group of patients (n ⫽ 78), oral steroid use was noted in 13 percent of patients preoperatively and 14 percent of patients postoperatively. Transtympanic dexamethasone was used in 18
percent of patients preoperatively and in 7 percent of patients postoperatively. A final group of patients consisted of patients with possible Ménière’s disease with vestibular symptoms by no cochlear manifestations (vestibular hydrops). The vast majority of these patients underwent ESD. The number of patients with possible Ménière’s disease who underwent EMS was not sufficient for analysis (n ⫽ 9). Of the patients within this group who experienced episodic vertigo (n ⫽ 26), vertigo control at 18- to 24-month follow-up was Class A (38%), Class B (23%), Class C (15%), Class D (4%), Class E (15%), and Class F (4%) (Table 2). Using questionnaire data from this group of patients (n ⫽ 28), when asked how the surgery affected their disease overall, 82 percent were improved, 18 percent were unchanged, and no patients reported worsening of symptoms. Average functional level preoperatively was 3.9 and average functional level at the time of the questionnaire was 2.3. Using the chart review data (n ⫽ 41), oral steroid use was noted in 22 percent of patients preoperatively and 7 percent of patients postoperatively. Transtympanic dexamethasone was used in 10 percent of patients preoperatively and 2 percent of patients postoperatively. Vertigo class was compared between the groups using 2 analysis. There was no statistical significance in outcome between the three groups (EMS-definite MD, ESD-definite MD, ESD-possible MD). Pre-operative and postoperative functional level scores were significantly different within each group using a paired student’s t test. When pre-operative functional levels were compared between groups, the patients with possible MD were significantly less disabled preoperatively than either group with definite MD, suggesting that these patients may have had less severe disease. Patients were staged according to pre-operative audiograms based on the Academy criteria (Table 3). In patients with definite Ménière’s who underwent EMS (n ⫽ 78), stage of disease was as follows: Stage 1 (15%), Stage 2 (24%), Stage 3 (53%), and Stage 4 (8%) (Table 4). Immediate postoperative audiograms demonstrated profound hearing loss in two patients (2.5%). One patient had a
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Table 3 Staging of definitive Ménière’s disease6 Stage
Pure tone average*
1 2 3 4
ⱕ25 26 to 40 41 to 70 ⬎70
*Pure tone average calculated at 0.5, 1, 2, and 4 kHz.
preoperative PTA of 80 dB, with SDS of 48 percent, whereas the other patient had a preoperative PTA of 58 and SDS of 72 percent. Audiograms within the 18- to 24-month follow-up period were reviewed (n ⫽ 37) and the average change in PTA showed an increase of 5.6 dB (P ⫽ 0.004). Average SDS was unchanged. When categorized into better, worse, or unchanged based on Academy criteria, 21 percent were better, 41 percent were unchanged, and 38 percent were worse within the 18- to 24-month time period (Fig 1). For those patients with definite Ménière’s who underwent ESD for which pre-operative audiograms where available (n ⫽ 66), 26 percent were Stage 1, 15 percent were Stage 2, 52 percent were Stage 3, and 8 percent were Stage 4 (Table 4). Immediate postoperative audiograms were reviewed and no profound losses were associated with ESD. Audiograms within the 18- to 24-month follow-up period were reviewed (n ⫽ 43) and the average change in PTA was a decrease of 1.4 dB (P ⫽ 0.25). Average SDS was again unchanged. When categorized into better, worse, or unchanged based on Academy criteria, 16 percent were better, 44 percent were unchanged, and 42 percent were worse at the 18- to 24-month time point (Fig 2). The hearing results are summarized in Table 4 and presented graphically in Figures 1 and 2. Table 4 Hearing outcomes at 18 to 24 months postoperatively
Stage 1 (%) Stage 2 (%) Stage 3 (%) Stage 4 (%) Pre-op PTA (dB) Post-op PTA (dB) Pre-op SDS (%) Post-op SDS (%) Average change in PTA (increase in dB) % improved % unchanged % worse
EMS
ESD
15 24 53 8 45 50 78 77
26 15 52 8 46 44 77 76
5.6 21 41 38
⫺1.4 16 44 40
EMS, endolymphatic mastoid shunt; ESD, endolymphatic sac decompression; PTA, Pure tone average; SDS, speech discrimination scores.
Figure 1 EMS.
Postoperative hearing at 18 to 24 months after
To determine long-term control of vertigo, patients in each group who had at least 30-month follow-up were then assigned a vertigo class based on the number of vertigo spells in the last 6 months of follow-up (Table 5). Among patients who underwent EMS (n ⫽ 44), an average follow-up of period of 81 months was obtained within this group. Vertigo class included Class A (45%), Class B (16%), Class C (14%), Class D (2%), Class E (0%), and Class F (23%). Among patients who underwent ESD for definite Ménière’s with ⬎30-month follow-up (n ⫽ 28; average follow-up, 51 months), vertigo class was Class A (43%), Class B (21%), Class C (11%), Class D (0%), Class E (7%), and Class F (18%). Among patients with possible Ménière’s who underwent ESD (n ⫽ 12; average follow-up, 47 months), vertigo class was Class A (42%), Class B (42%), Class C (8%), Class D (0%), Class E (0%), and Class F (8%). Using 2 analysis, no difference in vertigo class was observed between the three groups. Data from all patients who were followed for over 5 years were analyzed. Among patients with definite
Figure 2 ESD.
Postoperative hearing at 18 to 24 months after
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Endolymphatic mastoid shunt versus endolymphatic . . .
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Table 5 Long-term follow-up of vertigo control rates (>30 months) Control class
EMS-definite (n ⫽ 44) n (%)
ESD-definite (n ⫽ 28) n (%)
ESD-possible (n ⫽ 12) n (%)
Average follow-up (months) A B C D E F Pre-op functional level Post-op functional level
81 20 (45) 7 (16) 6 (14) 1 (2) 0 (0) 10 (23) 4.4 2.5
51 12 (43) 6 (21) 3 (11) 0 (0) 2 (7) 5 (18) 4.4 2.7
47 5 (42) 5 (42) 1 (8) 0 (0) 0 (0) 1 (8) 3.9 2.3
EMS, endolymphatic mastoid shunt; ESD, endolymphatic sac decompression.
Ménière’s disease who underwent EMS (n ⫽ 28), Vertigo results included Class A (41%), Class B (19%), Class C (13%), and Class F (28%). Preoperative functional level was 4.2 and postoperative functional level was 2.4. Among patients with definite Ménière’s disease that underwent ESD (n ⫽ 7), 43 percent were Class A, 29 percent were Class B, and 29 percent were Class F. Preoperative functional level was 4.5 and postoperative functional level was 3.6. Among those patients with possible Ménière’s disease who underwent ESD (n ⫽ 10), 50 percent were Class A, 40 percent were Class B, and 10 percent were Class F. Preoperative functional level was 4.3 and postoperative functional level was 2.4. To determine if the severity of disease determines outcome, patients were stratified based on preoperative hearing levels (stage) and outcomes were compared. All of these patients had definite Ménière’s based on hearing loss. Within the EMS group, those patients considered to have a successful outcome (Class A or B at 18 to 24 months), were as follows: Stage 1 (66%), Stage 2 (77%), and Stage 3 (70%). Only five patients were available for comparison with Stage 4 disease, but three of five were Class F. Within the ESD group, results were similar: Stage 1 (66%), Stage 2 (57%) (n ⫽ 7), and Stage 3 (65%). Only two patients were Stage 4. Severity of disease was also stratified by preoperative functional level (PFL). The vast majority of patients undergoing ESS had a preoperative level of 3, 4, or 5. This can be explained by the authors’ tendency to treat patient’s with mild disease with medical therapy and to treat patients with the most severe disease with destructive procedures. Among patients with definite Ménière’s disease who underwent EMS the results were as follows: PFL 3, Class A or B (72%); PFL 4, Class A or B (63%); PFL 5, Class A or B (88%). Among patients with definite Ménière’s disease who underwent ESD the results were as follows: PFL 3, Class A or B (65%); PFL 4, Class A or B (45%); PFL 5, Class A or B (75%). Finally, among patients with possible Ménière’s disease who underwent ESD the results were as follows:
PFL 3, Class A or B (80%), PFL 4, Class A or B (70%), PFL 5, Class A or B (70%).
DISCUSSION One must determine what is meant by success to determine the affect of surgery on Ménière’s disease. Using AAOO criteria, Class A represents complete control of vertigo, Class B represents a 60 percent or greater reduction in the number of vertigo spells, and Class C represents a 20 percent to 59 percent reduction in the number of vertigo spells. For the purpose of this study, those patients who experienced Class A or B results are considered to have a successful outcome. Accordingly, the success rate for ESD was 66 percent and for EMS was 67 percent in patients with definite Ménière’s disease. The number of patients with Class A results was slightly higher in the EMS group (43% vs 33%). Those patients with possible Ménière’s who underwent ESD experienced a similar outcome (Class A, 38%; Class B, 23%). The number of patients who subsequently underwent additional procedures was similar among patients with definite Ménière’s, although slightly higher in the group having undergone EMS (15% after ESD, 20% after EMS). Fewer patients with possible Ménière’s disease underwent additional procedures (4%), which represents most likely the surgeon’s reluctance to carry out destructive procedures on patients with an unclear diagnosis. These outcomes are similar to other reported series of ESS and suggest that ESD and EMS have similar outcomes when carried out for definite Ménière’s disease.7-9 These results also imply that ESS has a definite role in patients with vestibular hydrops, or possible Ménière’s disease. The true efficacy of ESS has been difficult to determine. With the exception of one study by Thomsen et al10 all work has been essentially retrospective. Also, it is somewhat difficult to compare studies using 1972 AAOO reporting guidelines11 with studies using 1995 guidelines. Some au-
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thors define success as complete relief of vertigo,12 whereas most others consider any significant degree of improvement in symptoms. Finally, the natural history of Ménière’s disease remains unclear.13-15 Silverstein followed 50 patients who refused surgery and found that 71% were free of vertigo at 7 years.16 When studies evaluating the effect of ESS with 1995 AAOO guidelines are considered, results show that 65 percent to 91 percent of patients have Class A or B vertigo after ESS.7-9 Pensak reviewed 96 patients with 5-year follow-up who underwent EMS and found 91% were Class A or B vertigo. Our results compare favorably with these studies; however, we cannot explain why Pensak experienced a substantially higher success rate. The effect of ESS on hearing is variable. Goin et al17 evaluated 30 patients that underwent EMS and compared these to 30 patients who either refused surgery or spontaneously improved. After 2 years, there was an average decrease in 9 dB in PTA and 16 percent SDS. No difference was found between those patients who underwent surgery and the control group. Ostrowski and Kartush7 found that 2 years after ESD, 60 percent of patients had improved hearing, however, with long-term follow-up, only 18 percent were improved, 64 percent were stable, and 18 percent declined. Brown18 evaluated 245 patients with 10-year follow-up who underwent either ESD, EMS, or both and noted that hearing was improved in 40 percent to 55 percent. Huang et al19 concluded that EMS stabilizes hearing after evaluating 723 patients with 76 months follow-up. Quaranta et al20 reviewed 68 patients who underwent either vestibular neurectomy, shunt, or medical therapy, and although the number of patients was relatively small, they did conclude that EMS did not alter the natural history of the disease. Arenberg21 reported on 214 shunts with 35-month follow-up and found that 60 percent had improved or stable hearing and 40 percent showed deterioration. In the present study, hearing results were similar in both groups, with a slight decline in PTA of 5.6 db in the EMS group and minimal change in the ESD group. Other authors have evaluated patients simultaneously who have undergone ESD with patients who underwent EMS.18,22 Neither of these studies included statistical analysis. This is the first study that compares ESD and EMS within the same institution using current AAOO criteria and when ESD was used when the sac was identified positively. Although SDS remained unchanged before and after the procedure in both groups, there was a statistically significant decrease in PTA in the EMS group. This decline in PTA was not observed in the ESD group. Two patients in this study were noted to have a profound sensorineural hearing loss after EMS. These results are consistent with the 1 percent to 2 percent incidence associated with endolymphatic shunt procedures.4 In the present study, no patients experienced profound hearing
loss after sac decompression alone, consistent with a review of the literature. Some authors have observed a decline in the efficacy of ESS with long-term follow-up.12 This decline did not occur in this study (Table 4). Long-term vertigo class was essentially unchanged when compared with the 18- to 24-month follow-up. There was a minimal increase in the percentage of patients who underwent a secondary procedure, but the majority of secondary procedures were carried out in the first 2 years of follow-up. Although the number of patients with long-term follow-up who underwent endolymphatic shunt surgery for possible Ménière’s disease was quite small (n ⫽ 12), we actually saw an increase in the percentage of patients with Class A and B vertigo over the longterm (61% increased to 84%). This may represent spontaneous improvement in the disease over time. All patients with follow-up ⬎5 years were also evaluated. Although the numbers of patients within each group were again relatively small, there was still minimal if any decline in the efficacy of the procedure, and we still were able to identify an increase in the Class A and B patients (90%) within the possible Ménière’s disease group. The vast majority of studies involving ESS limit evaluation to patients with definite Ménière’s disease. However, we were able to identify a considerable number of patients who did not meet Academy criteria for definite Ménière’s, but were offered ESS after having failed medical management for vestibular hydrops. By definition, these patients showed no evidence of hearing loss. Some patients in this group did experience definitive spells of vertigo lasting 20 minutes or more, others reported either a constant disequilibrium or brief daily spells of vertigo. Some patients reported aural fullness, tinnitus, or subjective hearing loss whereas others had no otologic symptoms. The constellation of symptoms and clinical findings (electrocochleography, ENG, etc) was evaluated on an individual basis to arrive at the diagnosis of hydrops. Interestingly, this group of patients responded as well to ESS as patients with definitive Ménière’s disease. In fact, in response to the questionnaire, 82 percent of patients reported improvement in their symptoms after ESD. This study does have some limitations. As mentioned previously, for the most part, the ESD and EMS operations were carried out by two different surgeons. This reflects the individual surgeon preference for a specific procedure. However, both surgeons use identical medical management and the groups did not differ significantly based on preoperative hearing stage or functional level. Therefore, we feel that this element of bias is kept to a minimum in this study. One factor that did differ was that patients who underwent ESD were more likely to receive transtympanic dexamethasone (TTdex) both pre- and postoperatively. Given that the outcomes between the groups are similar, one could either argue that TTdex either did not affect final vertigo or hearing results, or the success seen with ESD is in some part secondary to the use of TTdex.
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Endolymphatic mastoid shunt versus endolymphatic . . .
CONCLUSION In conclusion, both EMS and ESD are safe and equally effective procedures for controlling the vertigo associated with Ménière’s disease. Both procedures are likely to result in similar long-term hearing outcomes, although the risk of postoperative profound hearing loss is higher when the endolymphatic sac is incised. ESD is an effective procedure for patient with vestibular hydrops and should be offered to patients who fail medical management.
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8. Pensak ML, Friedman RA. The role of endolymphatic mastoid shunt surgery in the managed care era. Am J Otol 1998:139 – 43. 9. Smith DR, Pyle GM. Outcome-based assessment of endolymphatic sac surgery for Ménière’s disease. Laryngoscope 1997;107:1210 – 6. 10. Thomsen J, Bretlau P, Tos M, et al. Placebo effect in surgery for Ménière’s disease: a double-blind, placebo-controlled study on endolymphatic sac shunt surgery. Arch Otolaryngol 1981;107:271–7. 11. Brackmann DE, Anderson RG. Ménière’s disease: treatment with the endolymphatic subarachnoid shunt, a review of 125 cases. Otolaryngol Head Neck Surg 1980;107:271–7. 12. Jackson CG, Dickens JR, McMenomey S, et al. Endolymphatic system shunting: a long term profile of the Denver Inner Ear Shunt. Am J Otol 1996;17:85– 8. 13. Tokumasu K, Fujino A, Yoshio S, et al. Prognosis of Ménière’s disease by conservative treatment: retrospective study on the time course of the disease. Acta Otolaryngol Suppl 1995;519:216 – 8. 14. Filipo R, Barbara M. Natural course of Ménière’s disease in surgicallyselected patients. Ear Nose Throat J 1994;73:254 –7. 15. Stahle J, Frigerg U. Long term progression of Ménière’s disease. Am J Otol 1989;10:170 –3. 16. Silverstein H, Smoutha E, Jones R. Natural history vs. surgery for Ménière’s disease. Otolaryngol Head Neck Surg 1989;1:6 –16. 17. Goin DW, Mischke RE, Esses BA, et al. Hearing results from endolymphatic sac surgery. Trans Am Otol Soc 1991:139 – 43. 18. Brown JS. A ten year statistical follow-up of 245 consecutive cases of endolymphatic shunt and decompression with 328 cases of labyrinthectomy. Laryngoscope 1983;93:1419 –24. 19. Huang TS, Ching-Chen L, Yun-Lan C. Endolymphatic sac surgery for Ménière’s disease: a cumulative study of twelve years’ experience. Acta Otolaryngol Suppl 1991;485:145–54. 20. Quaranta A, Onofri M, Sallustio V, et al. Comparison of long-term hearing results after vestibular neurectomy, endolymphatic mastoid shunt, and medical therapy. Am J Otol 1997;18:444 – 8. 21. Arenberg IK. Results of endolymphatic sac to mastoid shunt surgery for Ménière’s disease. Am J Otol 1987;8:335– 44. 22. Huang TS. Valve implants compared to other methods. Am J Otol 1987;8:301– 6.
ORIGINAL RESEARCH
Endolymphatic mastoid shunt versus endolymphatic sac decompression for Ménière’s disease George M. Brinson, MD, Douglas A. Chen, MD, and Moisés A. Arriaga, MD, Wilmington, NC; and Pittsburgh, PA OBJECTIVE: This study compares the efficacy of endolymphatic mastoid shunt (EMS) versus endolymphatic sac decompression (ESD) without sac incision for the treatment of Ménière’s disease. STUDY DESIGN AND SETTING: The AAO-HNS Guidelines for the Diagnosis and Evaluation of Therapy in Ménière’s disease were used to retrospectively identify suitable candidates for the study. All patients who failed medical management and underwent either endolymphatic-mastoid shunt (EMS) (n ⫽ 88) or endolymphatic sac decompression (ESD) (n ⫽ 108) were selected for review using the AAO-HNS guidelines. The study was carried out at a tertiary care neurotology private practice. RESULTS: EMS and ESD were equally effective in reducing the incidence and severity of vertigo attacks with significant improvement in 67 percent and 66 percent of patients, respectively. CONCLUSION: Both EMS and ESD are effective, nondestructive alternatives for patients who have failed medical management of Ménière’s disease with similar long-term hearing outcomes. SIGNIFICANCE: This is the only study within the same institution using AAO-HNS guidelines comparing EMS versus ESD. © 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved.
1927.1 An extensive variety of procedures have since been described involving simple decompression, endolymphatic subarachnoid drainage, endolymphatic mastoid drainage, and, in some cases, removal of the extraosseous portion of the sac.2 Although some physicians claim remarkable success, others doubt the efficacy of sac surgery altogether. Our current understanding of the disease has recently been reviewed by Paparella and Djalilian.3 Multiple theories attempt to explain the mechanism by which ESS affects Ménière’s disease and include decompression of a tightly bound endolymphatic sac, neovascularization of the perisaccular region, passive diffusion of endolymph, and the creation of an osmotic gradient between the sac and the endolymph.4 Even though ESS has been surrounded by controversy, it still remains the most common surgical therapy carried out for the treatment of Ménière’s disease.5 The goal of this study is to compare the efficacy of endolymphatic sac decompression (ESD) with endolymphatic-mastoid shunt (EMS).
W
hen patients fail medical management of Ménière’s disease, surgical intervention is indicated to stabilize the disease. Options include endolymphatic sac surgery (ESS), transtympanic injection of gentamycin, labyrinthectomy, and vestibular nerve section. Endolymphatic sac enhancement is appealing to patients and surgeons because it is nondestructive and does not require a craniotomy. Endolymphatic sac surgery for the treatment of Ménière’s disease has been the subject of much discussion and controversy since it was first described by Portmann in
METHODS
From the Wilmington ENT, NC (Dr Brinson), and Pittsburgh Ear Associates, Allegheny General Hospital, PA (Drs Chen and Arriaga). Presented at the American Academy of Otolaryngology–Head and Neck Surgery, New York, NY, September 19-22, 2004.
Reprint requests: Douglas A. Chen, MD, Pittsburgh Ear Associates, Suite 402, Pittsburgh, PA 15212. E-mail address: [email protected].
All patients that underwent ESS at Pittsburgh Ear Associates between the years of 1992 and 2003 were identified through a retrospective chart review. The procedures were carried out by two different surgeons. One surgeon prefers EMS (D.A.C.) for patients with Ménière’s whereas the other surgeon prefers ESD (M.A.A.). All patients had failed medical therapy consisting of dietary salt and caffeine restriction, diuretics, subcutaneous histamine, and vestibular sup-
0194-5998/$32.00 © 2007 American Academy of Otolaryngology–Head and Neck Surgery Foundation. All rights reserved. doi:10.1016/j.otohns.2006.08.031
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pressants. The medical management used by each surgeon pre-and postoperatively was evaluated and did not differ significantly. A total of 108 patients had undergone ESD and 88 patients had undergone EMS. Preoperative data was obtained that included the extent of medical management, frequency of vertigo, extent of hearing loss, and degree of disability. Data was collected through a chart review as well as through a questionnaire, and 1995 AAO criteria were used in all data collection and reporting.6 Patients were diagnosed as having definite, probable, or possible Ménière’s disease. Those patients with possible Ménière’s disease carried the diagnosis of either vestibular or cochlear hydrops. Patients with definite Ménière’s disease were examined independently of those with possible Ménière’s disease. The vast majority of patients with possible Ménière’s disease underwent ESD. Those patients with purely cochlear hydrops were excluded from the study. The effect of surgery on vertigo symptoms was reported using the definition of class as defined by the AAO guidelines.6 The worst preoperative audiogram in the 6-month period before surgery was used as a baseline, and patients were divided into stage of disease based on Academy criteria.6 The worst audiogram in the period 18 to 24 months after surgery was used as the postoperative audiogram. Pure tone average (PTA) at 500 Hz, 1 kHz, 2 kHz, and 4 kHz and speech discrimination scores (SDS) were compared pre and postoperatively. Postoperative hearing was reported as better, worse, or the same based on AAO criteria: a change of 10 db or more in PTA or a change in SDS of 15 percentage points was considered clinically significant. The patient’s pre- and postoperative functional level was determined based on the questionnaire responses (Table 1). The affect of surgery on tinnitus, aural fullness, and overall disease was reported as better, worse, or the same based on questionnaire responses. IRB waiver was granted by our institution.
Surgical Technique ESD. Under general anesthesia, a simple mastoidectomy was carried out. The incus, horizontal canal, posterior canal, and sigmoid sinus were identified. The posterior fossa dura anterior to the sigmoid sinus as well as the most anterior portion of the sigmoid sinus was decompressed until the endolymphatic sac was identified. The sac itself and surrounding dura was then decompressed from the region of dense otic capsule bone superiorly to approximately 5 mm inferior to the sac. Surgicel was then placed between the dura and the remaining bone anteriorly to further decompress the sac and duct. EMS. The endolymphatic sac was approached and identified in the same manner as above. The sigmoid sinus was decompressed when necessary for exposure. The sac was then incised and the lumen identified. A T-shaped silastic shunt was then placed into the lumen itself.
Table 1 Functional Level Scale6 1. 2.
3.
4.
5.
6.
My dizziness has no effect on my activities at all. When I am dizzy I have to stop what I am doing for awhile, but it soon passes and I can resume activities. I continue to work, drive, and engage in any activity I choose without restriction. I have not changed any plans or activities to accommodate my dizziness. When I am dizzy I have to stop what I am doing for awhile, but it does pass and I can resume activities. I continue to work, drive and engage in most activities I choose, but I have had to change some plans and make some allowance for my dizziness. I am able to work, drive, travel, take care of a family, or engage in most essential activities, but I must exert a great deal of effort to do so. I must constantly make adjustments in my activities and budget my energies I am barely making it. I am unable to work, drive, or take care of a family. I am unable to do most of the active things that I used to. Even essential activities must be limited. I am disabled. I have been disabled for 1 year or longer and/or I receive compensation (money) because of my dizziness or balance problems.
Data Analysis Data was analyzed using Student’s t test or 2 analysis when appropriate. A value of P ⬍ 0.05 was considered statistically significant.
RESULTS A total of 196 patients were identified who underwent endolymphatic sac surgery. ESD was carried out on 108 patients and EMS was carried out on 88 patients. Average age was 47 for ESD and 53 for EMS. Questionnaires were returned by 135 (69%): 79 questionnaires in ESD group and 53 questionnaires in EMS group. Average follow-up either by chart review or questionnaire was 31 months for ESD patients and 53 months for EMS patients, the difference explained by the fact that EMS has been carried out since 1992, whereas ESD has essentially only been carried out since 1998. The class effect of the procedure was determined based on a combination of questionnaires and chart review. Numbers for the various outcomes may vary because data in some patients was unavailable. When reporting vertigo class at 18 to 24 months, patients with ⬍18-month follow-up were excluded. Among patients with definite Ménière’s undergoing EMS (n ⫽ 54), vertigo class at 18- to 24-months follow-up was Class A (43%), Class B (24%),
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Table 2 Vertigo control by class and functional level at 18 to 24 months follow-up Control class A B C D E F Pre-op functional level Post-op functional level
EMS-definite (n ⫽ 54) n (%)
ESD-definite (n ⫽ 40) n (%)
ESD-possible (n ⫽ 26) n (%)
23 (43) 13 (24) 2 (4) 4 (7) 2 (4) 11 (20) 4.4 2.5 (follow-up ⫽ 51 months)
13 (33) 13 (33) 5 (13) 1 (3) 2 (5) 6 (15) 4.4 2.7 (follow-up ⫽ 32 months)
10 (38) 6 (23) 4 (15) 1 (4) 4 (15) 1 (4) 3.9 2.3 (follow-up ⫽ 25 months)
EMS, endolymphatic mastoid shunt; ESD, endolymphatic sac decompression.
Class C (4%), Class D (7%), Class E (4%), and Class F (20%) (Table 2). Revision procedures within the 24-month period consisted of vestibular nerve section (n ⫽ 5), transtympanic gentamycin (n ⫽ 4), and labyrinthectomy (n ⫽ 1). Using questionnaire data (n ⫽ 52), this group of patients reported tinnitus improved (38%), unchanged (48%), and worse (14%). Aural fullness was improved in 39 percent, unchanged in 43 percent, and worse in 18 percent When asked how the surgery affected their disease overall, 77 percent were improved, 19 percent were unchanged, and 4 percent were worse. Average functional level preoperatively was 4.2 and average functional level at the time of the questionnaire was 2.5. Patients with Class F outcome were excluded from functional level outcome analysis. Using the chart review within this group of patients (n ⫽ 78), oral steroid use was noted in 24 percent of patients preoperatively and 1 percent of patients postoperatively. Transtympanic dexamethasone was used in 5 percent of patients preoperatively and in 1 percent of patients postoperatively. Among patients with definite Ménière’s who underwent ESD (n ⫽ 40), vertigo control at 18 to 24 months was Class A (33%), Class B (33%), Class C (13%), Class D (3%), Class E (5%), and Class F (15%) (Table 2). Among those patients with Class F outcome, four patients underwent vestibular nerve section and two patients received transtympanic gentamycin. Using questionnaire data (n ⫽ 44), this group of patients reported tinnitus improved (41%), unchanged (45%), and worse (14%). Aural fullness was improved in 45 percent, unchanged in 41 percent, and worse in 14 percent. When asked how the surgery affected their disease overall, 75 percent were improved, 18 percent were unchanged, and 7 percent were worse. Average functional level preoperatively was 4.2 and average functional level at the time of the questionnaire was 2.7. Again, patients with Class F outcome were excluded from functional level outcome analysis. Using the chart review from this group of patients (n ⫽ 78), oral steroid use was noted in 13 percent of patients preoperatively and 14 percent of patients postoperatively. Transtympanic dexamethasone was used in 18
percent of patients preoperatively and in 7 percent of patients postoperatively. A final group of patients consisted of patients with possible Ménière’s disease with vestibular symptoms by no cochlear manifestations (vestibular hydrops). The vast majority of these patients underwent ESD. The number of patients with possible Ménière’s disease who underwent EMS was not sufficient for analysis (n ⫽ 9). Of the patients within this group who experienced episodic vertigo (n ⫽ 26), vertigo control at 18- to 24-month follow-up was Class A (38%), Class B (23%), Class C (15%), Class D (4%), Class E (15%), and Class F (4%) (Table 2). Using questionnaire data from this group of patients (n ⫽ 28), when asked how the surgery affected their disease overall, 82 percent were improved, 18 percent were unchanged, and no patients reported worsening of symptoms. Average functional level preoperatively was 3.9 and average functional level at the time of the questionnaire was 2.3. Using the chart review data (n ⫽ 41), oral steroid use was noted in 22 percent of patients preoperatively and 7 percent of patients postoperatively. Transtympanic dexamethasone was used in 10 percent of patients preoperatively and 2 percent of patients postoperatively. Vertigo class was compared between the groups using 2 analysis. There was no statistical significance in outcome between the three groups (EMS-definite MD, ESD-definite MD, ESD-possible MD). Pre-operative and postoperative functional level scores were significantly different within each group using a paired student’s t test. When pre-operative functional levels were compared between groups, the patients with possible MD were significantly less disabled preoperatively than either group with definite MD, suggesting that these patients may have had less severe disease. Patients were staged according to pre-operative audiograms based on the Academy criteria (Table 3). In patients with definite Ménière’s who underwent EMS (n ⫽ 78), stage of disease was as follows: Stage 1 (15%), Stage 2 (24%), Stage 3 (53%), and Stage 4 (8%) (Table 4). Immediate postoperative audiograms demonstrated profound hearing loss in two patients (2.5%). One patient had a
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Table 3 Staging of definitive Ménière’s disease6 Stage
Pure tone average*
1 2 3 4
ⱕ25 26 to 40 41 to 70 ⬎70
*Pure tone average calculated at 0.5, 1, 2, and 4 kHz.
preoperative PTA of 80 dB, with SDS of 48 percent, whereas the other patient had a preoperative PTA of 58 and SDS of 72 percent. Audiograms within the 18- to 24-month follow-up period were reviewed (n ⫽ 37) and the average change in PTA showed an increase of 5.6 dB (P ⫽ 0.004). Average SDS was unchanged. When categorized into better, worse, or unchanged based on Academy criteria, 21 percent were better, 41 percent were unchanged, and 38 percent were worse within the 18- to 24-month time period (Fig 1). For those patients with definite Ménière’s who underwent ESD for which pre-operative audiograms where available (n ⫽ 66), 26 percent were Stage 1, 15 percent were Stage 2, 52 percent were Stage 3, and 8 percent were Stage 4 (Table 4). Immediate postoperative audiograms were reviewed and no profound losses were associated with ESD. Audiograms within the 18- to 24-month follow-up period were reviewed (n ⫽ 43) and the average change in PTA was a decrease of 1.4 dB (P ⫽ 0.25). Average SDS was again unchanged. When categorized into better, worse, or unchanged based on Academy criteria, 16 percent were better, 44 percent were unchanged, and 42 percent were worse at the 18- to 24-month time point (Fig 2). The hearing results are summarized in Table 4 and presented graphically in Figures 1 and 2. Table 4 Hearing outcomes at 18 to 24 months postoperatively
Stage 1 (%) Stage 2 (%) Stage 3 (%) Stage 4 (%) Pre-op PTA (dB) Post-op PTA (dB) Pre-op SDS (%) Post-op SDS (%) Average change in PTA (increase in dB) % improved % unchanged % worse
EMS
ESD
15 24 53 8 45 50 78 77
26 15 52 8 46 44 77 76
5.6 21 41 38
⫺1.4 16 44 40
EMS, endolymphatic mastoid shunt; ESD, endolymphatic sac decompression; PTA, Pure tone average; SDS, speech discrimination scores.
Figure 1 EMS.
Postoperative hearing at 18 to 24 months after
To determine long-term control of vertigo, patients in each group who had at least 30-month follow-up were then assigned a vertigo class based on the number of vertigo spells in the last 6 months of follow-up (Table 5). Among patients who underwent EMS (n ⫽ 44), an average follow-up of period of 81 months was obtained within this group. Vertigo class included Class A (45%), Class B (16%), Class C (14%), Class D (2%), Class E (0%), and Class F (23%). Among patients who underwent ESD for definite Ménière’s with ⬎30-month follow-up (n ⫽ 28; average follow-up, 51 months), vertigo class was Class A (43%), Class B (21%), Class C (11%), Class D (0%), Class E (7%), and Class F (18%). Among patients with possible Ménière’s who underwent ESD (n ⫽ 12; average follow-up, 47 months), vertigo class was Class A (42%), Class B (42%), Class C (8%), Class D (0%), Class E (0%), and Class F (8%). Using 2 analysis, no difference in vertigo class was observed between the three groups. Data from all patients who were followed for over 5 years were analyzed. Among patients with definite
Figure 2 ESD.
Postoperative hearing at 18 to 24 months after
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Table 5 Long-term follow-up of vertigo control rates (>30 months) Control class
EMS-definite (n ⫽ 44) n (%)
ESD-definite (n ⫽ 28) n (%)
ESD-possible (n ⫽ 12) n (%)
Average follow-up (months) A B C D E F Pre-op functional level Post-op functional level
81 20 (45) 7 (16) 6 (14) 1 (2) 0 (0) 10 (23) 4.4 2.5
51 12 (43) 6 (21) 3 (11) 0 (0) 2 (7) 5 (18) 4.4 2.7
47 5 (42) 5 (42) 1 (8) 0 (0) 0 (0) 1 (8) 3.9 2.3
EMS, endolymphatic mastoid shunt; ESD, endolymphatic sac decompression.
Ménière’s disease who underwent EMS (n ⫽ 28), Vertigo results included Class A (41%), Class B (19%), Class C (13%), and Class F (28%). Preoperative functional level was 4.2 and postoperative functional level was 2.4. Among patients with definite Ménière’s disease that underwent ESD (n ⫽ 7), 43 percent were Class A, 29 percent were Class B, and 29 percent were Class F. Preoperative functional level was 4.5 and postoperative functional level was 3.6. Among those patients with possible Ménière’s disease who underwent ESD (n ⫽ 10), 50 percent were Class A, 40 percent were Class B, and 10 percent were Class F. Preoperative functional level was 4.3 and postoperative functional level was 2.4. To determine if the severity of disease determines outcome, patients were stratified based on preoperative hearing levels (stage) and outcomes were compared. All of these patients had definite Ménière’s based on hearing loss. Within the EMS group, those patients considered to have a successful outcome (Class A or B at 18 to 24 months), were as follows: Stage 1 (66%), Stage 2 (77%), and Stage 3 (70%). Only five patients were available for comparison with Stage 4 disease, but three of five were Class F. Within the ESD group, results were similar: Stage 1 (66%), Stage 2 (57%) (n ⫽ 7), and Stage 3 (65%). Only two patients were Stage 4. Severity of disease was also stratified by preoperative functional level (PFL). The vast majority of patients undergoing ESS had a preoperative level of 3, 4, or 5. This can be explained by the authors’ tendency to treat patient’s with mild disease with medical therapy and to treat patients with the most severe disease with destructive procedures. Among patients with definite Ménière’s disease who underwent EMS the results were as follows: PFL 3, Class A or B (72%); PFL 4, Class A or B (63%); PFL 5, Class A or B (88%). Among patients with definite Ménière’s disease who underwent ESD the results were as follows: PFL 3, Class A or B (65%); PFL 4, Class A or B (45%); PFL 5, Class A or B (75%). Finally, among patients with possible Ménière’s disease who underwent ESD the results were as follows:
PFL 3, Class A or B (80%), PFL 4, Class A or B (70%), PFL 5, Class A or B (70%).
DISCUSSION One must determine what is meant by success to determine the affect of surgery on Ménière’s disease. Using AAOO criteria, Class A represents complete control of vertigo, Class B represents a 60 percent or greater reduction in the number of vertigo spells, and Class C represents a 20 percent to 59 percent reduction in the number of vertigo spells. For the purpose of this study, those patients who experienced Class A or B results are considered to have a successful outcome. Accordingly, the success rate for ESD was 66 percent and for EMS was 67 percent in patients with definite Ménière’s disease. The number of patients with Class A results was slightly higher in the EMS group (43% vs 33%). Those patients with possible Ménière’s who underwent ESD experienced a similar outcome (Class A, 38%; Class B, 23%). The number of patients who subsequently underwent additional procedures was similar among patients with definite Ménière’s, although slightly higher in the group having undergone EMS (15% after ESD, 20% after EMS). Fewer patients with possible Ménière’s disease underwent additional procedures (4%), which represents most likely the surgeon’s reluctance to carry out destructive procedures on patients with an unclear diagnosis. These outcomes are similar to other reported series of ESS and suggest that ESD and EMS have similar outcomes when carried out for definite Ménière’s disease.7-9 These results also imply that ESS has a definite role in patients with vestibular hydrops, or possible Ménière’s disease. The true efficacy of ESS has been difficult to determine. With the exception of one study by Thomsen et al10 all work has been essentially retrospective. Also, it is somewhat difficult to compare studies using 1972 AAOO reporting guidelines11 with studies using 1995 guidelines. Some au-
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thors define success as complete relief of vertigo,12 whereas most others consider any significant degree of improvement in symptoms. Finally, the natural history of Ménière’s disease remains unclear.13-15 Silverstein followed 50 patients who refused surgery and found that 71% were free of vertigo at 7 years.16 When studies evaluating the effect of ESS with 1995 AAOO guidelines are considered, results show that 65 percent to 91 percent of patients have Class A or B vertigo after ESS.7-9 Pensak reviewed 96 patients with 5-year follow-up who underwent EMS and found 91% were Class A or B vertigo. Our results compare favorably with these studies; however, we cannot explain why Pensak experienced a substantially higher success rate. The effect of ESS on hearing is variable. Goin et al17 evaluated 30 patients that underwent EMS and compared these to 30 patients who either refused surgery or spontaneously improved. After 2 years, there was an average decrease in 9 dB in PTA and 16 percent SDS. No difference was found between those patients who underwent surgery and the control group. Ostrowski and Kartush7 found that 2 years after ESD, 60 percent of patients had improved hearing, however, with long-term follow-up, only 18 percent were improved, 64 percent were stable, and 18 percent declined. Brown18 evaluated 245 patients with 10-year follow-up who underwent either ESD, EMS, or both and noted that hearing was improved in 40 percent to 55 percent. Huang et al19 concluded that EMS stabilizes hearing after evaluating 723 patients with 76 months follow-up. Quaranta et al20 reviewed 68 patients who underwent either vestibular neurectomy, shunt, or medical therapy, and although the number of patients was relatively small, they did conclude that EMS did not alter the natural history of the disease. Arenberg21 reported on 214 shunts with 35-month follow-up and found that 60 percent had improved or stable hearing and 40 percent showed deterioration. In the present study, hearing results were similar in both groups, with a slight decline in PTA of 5.6 db in the EMS group and minimal change in the ESD group. Other authors have evaluated patients simultaneously who have undergone ESD with patients who underwent EMS.18,22 Neither of these studies included statistical analysis. This is the first study that compares ESD and EMS within the same institution using current AAOO criteria and when ESD was used when the sac was identified positively. Although SDS remained unchanged before and after the procedure in both groups, there was a statistically significant decrease in PTA in the EMS group. This decline in PTA was not observed in the ESD group. Two patients in this study were noted to have a profound sensorineural hearing loss after EMS. These results are consistent with the 1 percent to 2 percent incidence associated with endolymphatic shunt procedures.4 In the present study, no patients experienced profound hearing
loss after sac decompression alone, consistent with a review of the literature. Some authors have observed a decline in the efficacy of ESS with long-term follow-up.12 This decline did not occur in this study (Table 4). Long-term vertigo class was essentially unchanged when compared with the 18- to 24-month follow-up. There was a minimal increase in the percentage of patients who underwent a secondary procedure, but the majority of secondary procedures were carried out in the first 2 years of follow-up. Although the number of patients with long-term follow-up who underwent endolymphatic shunt surgery for possible Ménière’s disease was quite small (n ⫽ 12), we actually saw an increase in the percentage of patients with Class A and B vertigo over the longterm (61% increased to 84%). This may represent spontaneous improvement in the disease over time. All patients with follow-up ⬎5 years were also evaluated. Although the numbers of patients within each group were again relatively small, there was still minimal if any decline in the efficacy of the procedure, and we still were able to identify an increase in the Class A and B patients (90%) within the possible Ménière’s disease group. The vast majority of studies involving ESS limit evaluation to patients with definite Ménière’s disease. However, we were able to identify a considerable number of patients who did not meet Academy criteria for definite Ménière’s, but were offered ESS after having failed medical management for vestibular hydrops. By definition, these patients showed no evidence of hearing loss. Some patients in this group did experience definitive spells of vertigo lasting 20 minutes or more, others reported either a constant disequilibrium or brief daily spells of vertigo. Some patients reported aural fullness, tinnitus, or subjective hearing loss whereas others had no otologic symptoms. The constellation of symptoms and clinical findings (electrocochleography, ENG, etc) was evaluated on an individual basis to arrive at the diagnosis of hydrops. Interestingly, this group of patients responded as well to ESS as patients with definitive Ménière’s disease. In fact, in response to the questionnaire, 82 percent of patients reported improvement in their symptoms after ESD. This study does have some limitations. As mentioned previously, for the most part, the ESD and EMS operations were carried out by two different surgeons. This reflects the individual surgeon preference for a specific procedure. However, both surgeons use identical medical management and the groups did not differ significantly based on preoperative hearing stage or functional level. Therefore, we feel that this element of bias is kept to a minimum in this study. One factor that did differ was that patients who underwent ESD were more likely to receive transtympanic dexamethasone (TTdex) both pre- and postoperatively. Given that the outcomes between the groups are similar, one could either argue that TTdex either did not affect final vertigo or hearing results, or the success seen with ESD is in some part secondary to the use of TTdex.
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Endolymphatic mastoid shunt versus endolymphatic . . .
CONCLUSION In conclusion, both EMS and ESD are safe and equally effective procedures for controlling the vertigo associated with Ménière’s disease. Both procedures are likely to result in similar long-term hearing outcomes, although the risk of postoperative profound hearing loss is higher when the endolymphatic sac is incised. ESD is an effective procedure for patient with vestibular hydrops and should be offered to patients who fail medical management.
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