Clinical Analysis Of 63 Cases Of Cochlear Implantation And Clinical And Image Studies Of Cochlear Position Malformation

PartⅠClinical Analysis of 63 Cases of Cochlear ImplantationObjective To analyze clinical data and problems encountered during perioperation,and investigate the issues associated with cochlear implantation, including preoperative assessment,surgical procedures,skills and complications.Materials and methods During the period of December 2005 to May 2008,a total of 63 cases(males 40 cases,females 23 cases)of cochlear implantation were performed in patients with bilateral profound sensorineural hearing loss(SHN)in the 2nd Xiangya Hospital of Central South University,via mastoidectomy with posterior tympanotomy approach(MPTA)using Combi 40+,a product of MedEl(Austria).The age ranged from 13 months to 11 years,with 62 prelingual and 1 postlingual deafness. The causes of deafness were ototoxic in 13,traumatic in 1,infective in 1,noise exposure in 2,positive family history in 1,undefined in 45.The issues associated with cochlear implantation and the surgical indications assessed by clinical examination, audiology and aural image,effect of hearing aids,lingual skill,intelligence and psychology were analyzed.Results Computer tomography(CT)magnetic resonance imaging(MRI)of temporal bone explored 2 cases of bilateral large vestibular aqueduct syndrome (LVAS),1 of bilateral Mondini deformity,others were normal.All the cases were confirmed of profound SHN by auditory brainstem response(ABR), multiple-frequency steady-state evoked potential(MFSSEP),distortion product otoacoustic emissions(DPOAE).The cochlear implantation was successful in all 63 cases,surgery for one times in 60 and twice in 3.1 of 2 cases of LVAS had only slight leakage of pelilymph,vertigo and vomit last for 3 days after operation,while another case had no abnormity.1 cases of Mondini deformity had "gush",and the "gush" stop right after inserting the electrodes.1 case had slight temporary facial paralysis,but recovered completely in one month.1 case had postoperative infection and split of incision,and then recovered after revision surgery.The electrodes were confirmed in the cochlea by postoperative X-rays of temporal bones in all patients.Mapping was done one month after surgery showing that the hearing recovered completely in all patients distinctly.Conclusions Cochlear implantation is an effected treatment for bilateral profound sensorineural hearing loss.The surgical indications,assessments by clinical examination,audiology and imageology,effect of hearing aids,lingual skill, intelligence and psychology,are the premises of the cochlear implantation.Severe cochleovestibular malformations such as large vestibular aqueduct syndrome and Mondini deformity are also indications for cochlear implantation with satisfied effect. The rate of complications is low,most of which are minor,appropriately assessments and skillfully surgical procedures are the key to reduce complications.PartⅡClinical and Image Studies of Cochlear Position MalformationObjective To find out CT parameters relative to cochlear position malformation by CT measurement and cases analysis of paediatric cochlear implant, and give advices to locate opening the cochlear correctly.Materials and methods All cases are divided to three groups according to selected criteria:①the normal children group:25 normal children's temporal CT;②the normal cochlear position group:temporal CT of 40 cases with normal cochlear position;③the cochlear position malformation group:temporal CT of 3 cases with cochlear position malformation.The age ranged from one year to 3 years old.The normal children group and the normal cochlear position group are respectively divided into three age group:one year to 3 years group,4 years to 7 years group,8 years to 11 years group.Each group measure 3 parameters respectively:①the angle of the basal turn of the cochlea relative to the sagittal plane(∠α);②the angle of line from the vertical portion of facial nerve to round window niche relative to the sagittal plane(∠β);③the vertical distance from the vertical portion of facial nerve to the posterior wall of external auditory canal at the level of round window(Distance A).All parameters were analyzed by independent-samples t test.Results①There are no significant differences between∠α,∠βand distance A in the normal children group and the normal cochlear position group,and no significant between each age group.The 95%reference ranges are∠α(53.4°,67.6°),∠β(35.4°,61.6°),Distance A(3.76mm,5.22mm).The mean and standard diviations are∠α60.5°±3.6°,∠β48.5°±6.7°and Distance A 4.49mm±0.37mm.②There are no significant differences between∠αand Distance A of 3 groups in consideration of age,but∠βof the cochlear position malformation group is significantly greater than others groups.③∠βof 3 cases of the cochlear position malformation group all exceed or are close to the upper limit of reference range.④We found that∠α＞∠βin the normal children group and the normal cochlear position group,by contrast,∠α＜∠βin the cochlear position malformation group.Conclusions Cochlear position malformation makes it difficult to open the cochlear.Cochlear position malformation can be cochlear rotation and/or cochlear displacement.∠αand∠βcan be used to assess the cochlear position and help to open cochlear correctly in cochlear implantation.The 95%reference ranges are∠α(53.4°,67.6°)and∠β(35.4°,61.6°),The mean and standard diviations are∠α60.5°±3.6°,∠β48.5°±6.7°.The cochlear maybe rotate forward or backward when∠αis not in the reference range,and cochlear may be displace backward when∠βexceed the upper limit of reference range or∠α＜∠β.