Malleus Neck-Anchoring Malleostapedotomy: Preliminary Results

Transcription

1 Otology & Neurotology 33:1477Y1481 Ó 2012, Otology & Neurotology, Inc. Malleus Neck-Anchoring Malleostapedotomy: Preliminary Results *Mun Young Chang, Jeong Hun Jang, *Jae-Jin Song, *Kyu-Hee Han, * Jun Ho Lee, * Seung Ha Oh, and * Sun O Chang *Department of OtorhinolaryngologyYHead and Neck Surgery, Seoul National University College of Medicine, Seoul; ÞDepartment of Otorhinolaryngology, Kyungpook National University College of Medicine, Daegu; and þsensory Organ Research Institute, Medical Research Center, Seoul National University College of Medicine, Seoul, Republic of Korea Objective: To compare the hearing outcomes between 2 malleostapedotomy (MS) procedures, handle-ms, connecting the prosthesis with the malleus handle and neck-ms, connecting the prosthesis with the malleus neck. Patients: Fourteen individuals having undergone MS in the setting of otosclerosis or congenital ossicular fixation from January 1983 through December Intervention: Review of preoperative and postoperative audiometric data, ossicular abnormalities, and postoperative complications. Main Outcome Measures: Postoperative air-bone gap (ABG), closure of ABG, and postoperative changes in bone conduction thresholds. Results: Of 14 patients, 7 underwent handle-ms, and 7 underwent neck-ms. Morphologic or functional abnormalities of the incus were identified in all cases. There was no significant sensorineural hearing loss. The mean postoperative ABGs were 19.8 T 11.9 db in the handle-ms group and 14.7 T 5.5dBintheneck- MS group. The postoperative ABGs for single frequencies revealed better results for neck-ms at all frequencies (0.25, 0.5, 1, 2, 3, and 4 khz) without statistical significance. The functional success rate (ABG closure, e10 db) was 28.6% for the handle- MS group and 42.9% for the neck-ms group (p ). Conclusion: Inasmuch as neck-ms is easy to perform and yields comparable results to those of handle-ms, it may be an alternative procedure of use in selected cases of otosclerosis or stapes fixation with incus anomaly. Key Words: Incus stapedotomyv MalleostapedotomyVOtosclerosis. Otol Neurotol 33:1477Y1481, Conventionally, malleostapedotomies have been performed by anchoring the prosthesis to the malleus handle (handle-ms). Although it is a good alternative surgical option in cases of otosclerosis and stapes fixation with an additional pathology of the incus, handle-ms has intrinsic drawbacks such as the prosthesis displacement and extrusion (1Y5). These problems are basically caused by the technique that anchors the prosthesis to the malleus handle. As a paradigm-shifting alternative technique, we have developed a malleostapedotomy that anchors the prosthesis to Address correspondence and reprint requests to Sun O Chang, M.D., Ph.D., Department of Otorhinolaryngology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul , Republic of Korea; suno@snu.ac.kr Mun Young Chang, Jeong Hun Jang, and Jae-Jin Song equally contributed to this work. Funding: None The authors disclose no conflicts of interest. Ethical approval: The study was approved by the institutional review boards at the Seoul National University Hospital (IRB No. H ). the malleus neck (neck-ms) to reduce the risk of prosthesis displacement or extrusion. Hereinafter, we introduce the technique of neck-ms and compare preliminary hearing outcomes between the handle- MS and neck-ms groups in our series and list the advantages of neck-ms. MATERIALS AND METHODS Patients A total of 20 patients who underwent malleostapedotomy by 4 surgeons between 1983 and 2009 were reviewed. Of 20 patients, 14 patients (70.0%) with available audiometric data were finally enrolled in the current study and classified into 2 groups according to the procedure: the handle-ms group (n = 7) and neck-ms group (n = 7). Surgical Procedures of Handle- and Neck-MS An endaural incision was carried out, and a tympanomeatal flap was developed. A piece of soft tissue was harvested from the subcutaneous fat at the incision site for future use. After 1477

2 1478 M. Y. CHANG ET AL. FIG. 1. Preparation of platinum-wire-piston prosthesis. The loop of PWP was hyperextended 20- (Ú) to be crimped over the medial side of the malleus neck and the platinum shaft angulated anteriorly 15 degrees, superiorly 15 degrees (Ù) from the Teflon piston. identifying the short malleal process, pyramidal process, and tympanic segment of the facial nerve, mobility of the ossicles was assessed by gentle palpation using a 1.5-mm 45-degree hook in the horizontal and vertical planes. This palpation permitted identification of the origin of the conductive hearing loss. When we found osseous fixation of the malleus during this procedure, it was released by KTP lasering of the scutum side with caution not to damage the malleus neck. In revision stapedotomy cases, excessive fibrous tissue covering the footplate was removed with a 0.2-mm stapes elevator until the remnant of the stapes footplate was clearly visible. For these revision cases, manual perforators were used to create a 0.5-mm opening through the remnant footplate. For fresh cases, a KTP laser (ForTec Medical Inc, Streetsboro, OH, USA) or Skeeter drill (Medtronic-Xomed Inc, North Jacksonville, FL, USA) with a 0.5-mm diamond burr was used to create a footplate opening. After measuring the distance from the stapes footplate to the malleus, the length of the prosthesis was chosen so that the lower end of the prosthesis could be inserted into the vestibule to a depth of 0.5 mm below the level of the footplate. A 0.4-mm-diameter platinum-wire-piston (PWP) prosthesis (Medtronic-Xomed Inc.) was trimmed to the desired length, usually 6 mm. Because the malleus neck is off-centered from the footplate center, the loop of the PWP was hyperextended 20 degrees to be crimped over the medial side of the malleus neck, and the platinum shaft was angulated anteriorly 15 degrees and superiorly 15 degrees from the Teflon piston for orthogonal location of the long axis of prosthesis between the malleus handle and stapes footplate (Fig. 1). Then, the loop of the prosthesis was anchored around the malleus neck, and the mobility of the prosthesis was verified by palpation (Fig. 2). The preharvested connective tissue pledgets were applied with fibrin glue (Greencross, Gyeonggi- Do, Korea) to seal the stapedotomy opening after introduction of the prosthesis. Connective tissue pledgets were also placed between the malleus handle or neck and the prosthesis. Then, the tympanomeatal flap was replaced. Audiometric Evaluations The preoperative and 1-year postoperative audiograms of the patients were analyzed based on the guidelines of the American Academy of OtolaryngologyYHead and Neck Surgery (6). A separate analysis, measurement of the postoperative air-bone FIG. 2. Schematic illustration (A), intraoperative findings (B), and postoperative temporal bone computed tomography findings (C) ofneck- malleostapedotomy. The loop of the platinum-wire-piston prosthesis is anchored around the malleus neck (B, arrow), and the lower end of the prosthesis is inserted into the vestibule.

3 MALLEUS NECK-ANCHORING MALLEOSTAPEDOTOMY 1479 TABLE 1. Clinical data of patients who underwent malleostapedotomy MS Case no. Sex/age Previous operation Diagnosis Ossicular anomalies Handle-MS 1 F/46 yr V Congenital ossicular fixation I: absent, S: fixed footplate only 2 F/23 yr Intact canal wall mastoidectomy, Otosclerosis I: absent, S: fixed ossiculoplasty with PORP 3 F/66 yr Incus stapedotomy Otosclerosis I: eroded long process 4 M/4 yr V Congenital ossicular fixation M: fixed, I: shortened long process, I-S joint: disconnected, S: fixed footplate only 5 M/10 yr V Congenital ossicular fixation M: fixed, I: shortened long process, I-S joint: fusion, S: posterior crus disconnected to footplate only and fixed footplate 6 M/10 yr V Congenital ossicular fixation M: fixed, I: shortened long process, S: fixed 7 F/49 yr V Otosclerosis I: absent, S: fixed, tilted posteriorly neck-ms 1 F/36 yr V Otosclerosis I: absent, S: fixed 2 F/31 yr V Otosclerosis I: shortened long process, S: fixed 3 F/15 yr Incus stapedotomy Congenital ossicular fixation I: eroded long process without anomaly 4 F/13 yr V Congenital ossicular fixation 5 M/11 yr V Congenital ossicular fixation without anomaly 6 F/5 yr V Congenital ossicular fixation 7 F/50 yr Ossiculoplasty with MSA Otosclerosis I: absent, S: fixed I: anomalous long process, I-S joint: disconnected, S: fixed posterior crus and footplate only I, S: fixed I: anomalous long process and lenticular process missing, S: fixed F indicates female; I, incus; M, male; M, malleus; MS, malleostapedotomy; MSA, malleus-stapes assembly; PORP, partial ossicular replacement prosthesis; S, stapes; yr, years. gap (ABG) for 6 frequencies was performed. The mean of the thresholds at 0.5, 1, 2, and 3 khz was used to calculate the pure tone average (PTA). The closure of the ABG was analyzed by subtracting the postoperative ABG from the preoperative ABG. The postoperative changes in BC were calculated for 1, 2, and 4 khz by subtracting the postoperative BC threshold from the preoperative BC threshold. A postoperative change in BC threshold for these frequencies exceeding 10 db was considered significant (1). Mann-Whitney U test was performed for statistical analysis (SPSS, Chicago, IL, USA). The criterion for statistical significance was set at p G RESULTS than that of the handle-ms group (19.8 T 11.9; range, 4.4Y36.3 db) without statistical significance. The mean ABG closure of the neck-ms group (26.1 T 15.9; range, j2.5 to 45.6 db) was almost the same as that of the handle- MS group (26.6 T 15.2; range, 12.5Y48.1 db) (p ). The postoperative ABGs for all frequencies showed better improvement in the neck-group than the handle-group without statistical significance (Fig. 3). No significant postoperative sensorineural hearing loss developed in either group. In 1 case, prosthesis extrusion occurred 8.5 years after initial handle-ms. For this case, the prosthesis was partially cut, and revision tympanoplasty with cartilage reinforcement was performed. The characteristics of the subjects are described in Table 1. The comparison of the postoperative hearing outcomes between the handle- and neck-ms groups is summarized in Table 2. The mean postoperative ABG of the neck-ms group (14.7 T 5.5; range, 9.4Y23.1 db) was smaller TABLE 2. The postoperative air-bone gaps after malleostapedotomy (db) n (%) Handle-MS group n (%) Neck-MS group n (%) e10 5 (35.7) 2 (28.6) 3 (42.9) 11Y20 5 (35.7) 2 (28.6) 3 (42.9) 21Y30 3 (21.4) 2 (28.6) 1 (14.3) (7.1) 1 (14.3) 0 (0.0) Total 14 (100.0) 7 (100.0) 7 (100.0), average of 4 frequencies (0.5, 1, 2, and 3 khz) by subtracting the postoperative bone conduction threshold from the postoperative air conduction threshold. FIG. 3. Mean postoperative air-bone gap (postoperative air minus postoperative bone) for handle- and neck-ms.

4 1480 M. Y. CHANG ET AL. DISCUSSION Although the sample size is small, the average postoperative ABG closure rates within 10 and 20 db of all MS patients in the current study, were 35.7% and 71.4%, which shows that our surgical outcomes are comparable to the outcomes reported in previous literature with closure rates within 10 and 20 db and the incidence of sensorineural hearing loss ranging from 18% to 70%, 67% to 88%, and 0% to 16%, respectively (Table 3) (1,7Y12). Suggested Surgical Techniques for Handle-MS and Comparison to Those of Our Neck-MS For handle-ms, previous researchers have suggested crimping of the prosthesis to the manubrium in a tight wraparound manner because a loose prosthesis causes resorption osteitis at the site of contact with the bone and eventual extrusion (7). In our neck-ms, we attempted to avoid excessive pressure to the malleus neck, and we aimed for a firm anchorage of the prosthesis at the same time. Another study proposed the use of a relatively long prosthesis in handle-ms so that the depth of insertion into the vestibule (1Y1.25 mm) was deeper than that in conventional incus stapedectomy (0.25 mm) (8). However, the drawback of this procedure was transient dizziness in 50% of patients, although this subsided within weeks in most cases. There was no postoperative vertiginous symptom in our series, and it may be attributed to the fact that we tried not to overinsert the prosthesis tip to the vestibule. Sarac et al. (8) suggested introducing a bend in the wire of the prosthesis so that the long axis of the prosthesis can be located orthogonal to the plane of the stapes footplate, with this configuration ensuring an optimum angle for good transmission of sound at the interface between the prosthesis and the vestibule. Anatomically, the malleus is usually positioned anteriorly to the stapes footplate (4). Therefore, while performing neck-ms, the loop of the PWP was hyperextended to be crimped over the medial side of the malleus neck, and the wire shaft was bended anteriorly and superiorly so that the long axis of the prosthesis became orthogonal to the plane of the stapes footplate (Fig. 1). This hyperextension of the loop of PWP and anterior and Authors TABLE 3. Review of literature data concerning the malleostapedotomy No. of ears of e10 db (%) of e20 db (%) SNHL (%) Sheehy (9) Schuknecht and Bartley (7) Tange (10) Fisch et al. (1) Hausler (11) Sarac et al. (8) Dalchow (12) SNHL indicates sensorineural hearing loss. superior bending procedure of the platinum shaft may be of importance in achieving successful hearing results. Advantages of Neck-MS Compared With Handle MS Our novel neck-ms has several advantages compared with handle-ms. First, our neck-ms can reduce the risk of prosthesis displacement and extrusion. Through a morphologic study of the malleus handle, it was pointed out that the prostheses anchored to the malleus handle were relatively unstable because of the rapidly decreasing diameter of the malleus handle toward the umbo (4). The loop of the prosthesis encircling the manubrium is closely located to the inner layer of the tympanic membrane (TM), and therefore, repetitive vibration of the TM by sound stimulation may result in abrasion and even perforation. Moreover, the prosthesis bypasses ossicular joints, such as the malleoincudal joint and the incudostapedial joint, which play an important role as excursion-attenuating mechanism (13). Indeed, we experienced 1 case of prosthesis extrusion after handle-ms (9). However, by anchoring the prosthesis to the malleus neck and inserting a piece of soft tissue between the TM and the loop of the prosthesis, the risk of prosthesis displacement and extrusion may be much reduced. Second, from a technical point of view, elevation of the TM in neck-ms is more conservative than that in handle- MS because the latter requires wide exposure of the malleus handle, whereas the former only requires sufficient exposure of the Prussak s space. Thus, our neck-ms may enable surgeons to save operation time and avoid adversely affecting the integrity of the connection between the TM and the malleus. CONCLUSION Taken together, the present study introduced a novel surgical procedure, namely, malleus neck-anchoring malleostapedotomy. Inasmuch as neck-ms is easy to perform and showed comparable results to those of handle-ms, it may be an alternative procedure of use in selected cases of otosclerosis or stapes fixation with incus anomaly. REFERENCES 1. Fisch U, Acar GO, Huber AM. Malleostapedotomy in revision surgery for otosclerosis. Otol Neurotol 2001;22:776Y Schmid P, Hausler R. Revision stapedectomy: an analysis of 201 operations. Otol Neurotol 2009;30:1092Y Todd NW. Orientation of the manubrium mallei: inexplicably widely variable. Laryngoscope 2005;115:1548Y Kwok P, Fisch U, Nussbaumer M, et al. Morphology of the malleus handle and the comparison of different prostheses for malleostapedotomy. Otol Neurotol 2009;30:1175Y Park KT, Suh MW, Song JJ, et al. Clinical manifestations and surgical results of malleostapedotomy and malleostapedectomy. Korean J Otorhinolaryngol Head Neck Surg 2008;51:985Y Committee on Hearing and Equilibrium guidelines for the evaluation of results of treatment of conductive hearing loss. American Academy of OtolaryngologyYHead and Neck Surgery Foundation, Inc. Otolaryngol Head Neck Surg 1995;113:186Y7.

5 MALLEUS NECK-ANCHORING MALLEOSTAPEDOTOMY Schuknecht HF, Bartley ML. Malleus grip prosthesis. Ann Otol Rhinol Laryngol 1986;95:531Y4. 8. Sarac S, McKenna MJ, Mikulec AA, et al. Results after revision stapedectomy with malleus grip prosthesis. Ann Otol Rhinol Laryngol 2006;115:317Y Sheehy JL. Stapedectomy: incus bypass procedures. A report of 203 operations. Laryngoscope 1982;92:258Y Tange RA. Ossicular reconstruction in cases of absent or inadequate incus, congenital malformation of the middle ear and epitympanic fixation of the incus and malleus. ORL J Otorhinolaryngol Relat Spec 1996;58:143Y Hausler R. 5 Advances in stapes surgery. In: Jahnke K, ed. Middle Ear Surgery: Recent Advances and Future Directions. New York, NY: Georg Thieme Verlag, 2004:95Y Dalchow CV, Dunne AA, Sesterhenn A, et al. Malleostapedotomy: the Marburg experience. Adv Otorhinolaryngol 2007;65:215Y Huttenbrink KB. Biomechanics of stapesplasty: a review. Otol Neurotol 2003;24:548Y57; discussion 57Y9.