Background: There are no reports about comprehensive comparative analysis of the effects after various hearing surgery solutions for congenital malformation of the middle and outer ear (CMMOE).
Aims/objectives: To analyze the improvement of Average Air-Conduction Threshold (AACT) of pure tone after various hearing surgery solutions for CMMOE and provide a reference for the selection of accurate hearing solutions.
Materials and methods: A retrospective analysis of 159 cases (170 ears) with CMMOE submitted to various ear surgery solutions, including: (1) Three situations of outer ear canal (OEC): ① atresia 85 ears, ② stenosis 28 ears, and ③ normal 57 ears. (2) Three commonly used hearing solutions: eardrum repair 53 ears, Porp 44 ears and Piston 32 ears implantation. (3) Three OEC situations with different hearing solutions: type I. Reconstruction of OEC (r-OEC), type II. r-OEC and/or different tympanoplasty, including ① eardrum repair, ② release of ossicular chain, ③ Porp implantation, and ④ Torp implantation, type III. Piston implantation with fenestration of the inner ear. Compare AACT of postoperative short term (0.5 years) or long term (0.5-10 years) and preoperative in the speech frequency range of 0.5-4 kHz to assess efficacy. If the sample number ≥10, and not subject to normal distribution, the Kruskal-Wallis multi-sample rank sum test is used for the comparison of multiple groups and Wilcoxon's rank sum test for two groups, with P < 0.05 being statistically significant. If the sample size <10, the standard of clinical efficacy is one frequency improvement value ≥15 dB HL, or 10 dB HL ≤2 frequency improvements <15 dB HL at 0.125-8 KHz.
Results: Intra-group comparison of AACT: (1) three situations of OEC: atresia, stenosis and normal all had P < 0.05 postoperatively in short term, while in long term only the normal group had P < 0.05. (2) Three commonly used hearing solutions: eardrum repair, Porp and Piston implantation all had P < 0.05 in short and long terms, except for eardrum repair P >0 .05 in long term. (3) Three OEC situations with different hearing solutions: 1) Atresia of OEC: Porp and Piston implantation, r-OEC and release of ossicular chain were effective in short term and were not effective in long term, and the eardrum repair was not effective in both short and long term. 2) Stenosis of OEC: eardrum repair, Porp and Piston implantation were effective in short and long term. r-OEC P >0 .05 for short and long term, Torp implantation was not effective in long term, 3) Normal of OEC: Porp, Torp and Piston implantation were all P < 0.05 in short and long term except for Torp >0.05 in long term, and release of ossicular chain is both short and long term clinically effective. The AACT values of postoperative in long term for three groups of atresia, stenosis, normal of OEC are over 58.7 dB HL (except Porp implantation 52.5 dB HL), 51.3 dB HL (except Porp implantation 42.5 dB HL), and 37.5 dB HL (except Torp implantation are 32.6 dB HL), respectively.
Conclusions and significance: Intra-group comparison of AACT. (1) Three groups of the atresia, stenosis and normal of OEC are all effective in short term, while in long term only the normal group is effective. (2) The three most commonly used surgical solutions of eardrum repair, Porp and Piston implantation are effective in short and long terms, except for long term eardrum repair. (3) Three OEC situations with different hearing solutions: some of surgical solutions were effective in short term or long term for CMMOE, but based on the AACT values of postoperative in long term for three OEC situations, it is better to choose a hearing device for atresia of OEC, comprehensive review of surgical or hearing device for stenosis of OEC. Surgery can be considered for normal OEC.
Keywords: Average air-conduction threshold (AACT) of pure tone; Congenital malformation of the middle and outer ear (CMMOE); Outer ear canal (OEC); Tympanoplasty.