|Year : 2015 | Volume
| Issue : 3 | Page : 194-196
Abnormalities of incus in chronic otitis media and methods of ossiculoplasty using remnants of incus or cartilage
Sohil I Vadiya
Department of ENT, Pramukh Swami Medical College and Shree Krishna Hospital, Karamsad, Gujarat, India
|Date of Web Publication||17-Jul-2015|
Sohil I Vadiya
Department of ENT, Pramukh Swami Medical College and Shree Krishna Hospital, Karamsad - 388 325, Gujarat
Source of Support: None, Conflict of Interest: None
Aim and Objective: To study various erosion patterns related to incus and observe results of various methods of ossiculoplasty using autologous incus or cartilage. Materials and Methods: A total 82 cases found suitable for the study having some abnormalities of incus with inclusion criteria being presence of intact and normal malleus and stapes and where canal wall preserved. Cases were divided into four groups with group A having minimum erosion of lenticular process and group D includes those cases where incus found absent. Results: Appropriate methods of ossiculoplasty performed using remnant of incus or tragal cartilage and hearing results compared. More than 75% of cases had a postoperative air-bone gap (ABG) <25 db in all groups with group C having 85% of cases with <25 db ABG at 1-year after surgery. No statistically significant difference observed in ABG at 3 months and 1-year. Conclusion: Abnormalities of incus are commonly observed during tympanomastoid surgeries and ossiculoplasty using remnant of incus or cartilage offers a good improvement in hearing.
Keywords: Cartilage shield, Incus erosion, Incus interposition, Ossiculoplasty
|How to cite this article:|
Vadiya SI. Abnormalities of incus in chronic otitis media and methods of ossiculoplasty using remnants of incus or cartilage. Indian J Otol 2015;21:194-6
|How to cite this URL:|
Vadiya SI. Abnormalities of incus in chronic otitis media and methods of ossiculoplasty using remnants of incus or cartilage. Indian J Otol [serial online] 2015 [cited 2020 Feb 26];21:194-6. Available from: http://www.indianjotol.org/text.asp?2015/21/3/194/159704
| Introduction|| |
Incus is the most common ossicle to be affected by chronic otitis media (COM), more commonly by the squamosal variety of the disease. Abnormalities of the incus found during tympanomastoid surgery vary from complete absence of the ossicle to mere partial erosion of the lenticular process. To restore hearing in such conditions is an important concern. To reconstruct the incus, various methods have been described. Incus interposition (transposition), use of bone cement, use of partial ossicular replacement prosthesis (PORP) of various materials, use of cartilage for bridging the Incudostapedial (IS) joint or type III cartilage shield tympanoplasty (CST) are some of the methods. According to Siddiq and East,  the long-term results of incus transposition are good whereas Donaldson and Snow  have observed deterioration in hearing with time in patients of incus transposition. Celenk et al.,  have concluded that incus interposition and bone cement ossiculoplasty are safe and reliable methods with which to manage incus long process defects. Kyrodimos et al.  have concluded that type III CST is an effective technique for hearing an improvement in selected patients and the results of this technique are similar to PORP. The current study aims at studying the abnormalities of incus during tympanomastoid surgeries and observing outcomes of various techniques used to improve hearing.
| Materials and Methods|| |
Cases of squamosal and mucosal type of COM were included in the study. Only those cases of squamosal variety included where a canal wall up (CWU) procedure was performed. Only the cases where the graft was completely taken up were included in the study. Those cases where malleus and stapes were present and healthy were included in the study. Preoperative assessment includes thorough history taking, examination under a microscope and by an oto - endoscope as it provides a better view and a pure tone audiogram (PTA). All procedures are done under general anesthesia and postaural skin incision approach used in all cases. Vascular strip incision used after infiltration and canal flap elevated. Pathological tissues completely removed from the middle ear. Ossicular chain inspected and findings noted. Mobility of the ossicular chain also checked and confirmed with observation of round window. Proper method of reconstruction was applied wherever required. Autologous bone or cartilage used for ossicular reconstruction in all cases. Temporalis fascia had been used as the grafting material in all cases. Patients were instructed to come for follow-up at 1, 3, and 6 weeks after surgery and then every 3 months for a year. PTA done at 3 months and then on every subsequent visit. Comparison and statistical analysis done for the air-bone gap (ABG) at 3 months and 1-year. Average of hearing thresholds at 500, 1000, and 2000 Hz frequency used for all statistical analysis.
| Results|| |
A total of 82 cases found suitable to be included in the study. The most common abnormality of incus was a partial erosion of the lenticular process and the bony continuity and mobility is still maintained between incus and stapes [Figure 1]. In these cases, only fascia grafting was done and no other changes made among the ossicles. These cases were classified as group A. Total 24 such cases observed in the study. Group B includes those cases where the lenticular process was completely eroded and a fibrous band found between long process of incus and stapes head. In these cases, a small piece of tragal cartilage was kept between incus and stapes after cutting the fibrous band (cartilage bridging). It was checked repeatedly that the small cartilage piece is snugly fit. This is possible in this group of patients as the gap is small. Adequate gelfoam kept in middle ear to prevent slippage. 21 such cases observed. If the gap between incus and stapes was more [Figure 2], then those cases were included in the group C and a total of 20 such cases were observed. Incus interposition method was used in these patients where remnant incus was healthy. Here, the remnant of incus removed and sculpted under a microscope, using small diamond burr, and putting it back between malleus handle and stapes head, making sure that the tension between the ossicles is optimum. There were seven cases in group C, of squamosal COM, where the remnant incus was eroded at multiple places or surrounded by squamous epithelium. In these cases, the unhealthy incus was excised and type III CST was performed. Group D includes the cases where incus was completely absent during surgery. 17 such cases observed and 13 of them were of squamosal variety. [Table 1] shows the distribution of disease of all four groups.
Twenty (83.3%) among group A patients had ABG <25 db at 3 months, with average preoperative ABG being 38.81 db and average postop ABG 23.61 db, and no significant change observed at 1-year after surgery. Worsening of hearing not seen in any cases in this group. Rest of the 4 cases had postop ABG between 25 and 40 db. The most important consideration is to correctly identify the IS joint configuration under a good quality microscope. It has been further observed that minimum ×16 provides good view of minute details. In group B, average preoperative ABG was 41.27 db and average postoperative ABG 24.12 db at 3 months and 24.84 db at 1-year. No significant difference found between hearing results at 3 months and at 1-year. (P = 0.714). For group C, average preoperative ABG had been 42 db and average postoperative ABG 22.91 db at 3 months and 23.02 db at 1-year. No significant change in hearing results observed at 1-year with P value being 0.9430. For group D, average preoperative ABG was 41.07 and average postoperative ABG was 24.90 db at 3 months and 24.21 db at 1-year (P = 0.7144). [Table 2] shows hearing results of various groups.
If an attico-antral (squamosal) disease permits a CWU procedure and ossiculoplasty at the same time of disease clearance when malleus and stapes are intact and healthy, then appropriate ossiculoplasty is performed in the same manner as in cases of tubotympanic (mucosal) type of disease. In our study, a total 34 cases had been of squamosal variety and 48 cases were of mucosal variety of COM. Postoperative results do not show statistically significant difference in hearing outcomes between these two types of cases (P = 0.1954).
| Discussion|| |
Ceccato et al.  have concluded that the audiometric results obtained among patients with an incus transposition are better than those obtained with a PORP Titanium prosthesis. Other advantages of using patient's own tissue are the lowest rates of extrusion and granulations. Cost of titanium is also a significant consideration for patients in India. The current study aims at utilizing patient's autologous bone or cartilage for ossiculoplasty when stapes and malleus are present and healthy. Schuring and Lippy  have used the incus after creating a window in its body and placing it between stapes and malleus. Ozer et al.  have observed good hearing outcomes in selected patients by using bone cement to bridge the gap between incus and stapes. Pennington  has explained incus interposition techniques and also confirmed that long-term results are satisfactory.  O'Reilly et al.,  have concluded that Sculpted autologous or homologous incus interposition provides hearing success comparable with current allograft prosthesis studies, has a very low extrusion rate, and remains stable over time. Sismanis and Poe  recommend type III CST that obviates the use of any prosthesis whatsoever for type A ossicular defects according to the Austin classification. 
| Conclusion|| |
By using either incus interposition or cartilage type III shield method, it is possible to avoid using external materials for ossiculoplasty in cases of incus abnormalities during tympanomastoid surgeries. The hearing outcomes are satisfactory and complication rate is low.
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[Figure 1], [Figure 2]
[Table 1], [Table 2]