| As one of the most common disabilities,hearing loss seriously impedes the patient's speech and cognitive development and learning ability,which leads to defects in communication,psychology and behavior,and also imposes a heavy burden on families and society.Especially for younger children,the adverse consequences of hearing loss are more serious.Numerous studies have confirmed that early and timely intervention was extremely important to help children return to mainstream society.Cochlear implant(Cl)is recognized as the most effective and stable method for the treatment of severe-to-profound sensorineural hearing loss.It has helped many deaf patients to reconstruct their hearing and gain the ability to communicate normally with others.As the population grows and the indications for cochlear implantion continue to expand,more and more younger children will accept Cls.However,how to get better auditory and speech functions development is a common concern of the patients,clinicians and rehabilitation teachers.For a long time,the influence of various factors on postoperative results is one of the research hotspots in the field of CI.Exploring and evaluating the factors affecting the effect of CI can provide us with an in-depth understanding of the plasticity of postoperative auditory and speech development.It is of great significance for controlling the indications of CIs,predicting postoperative effects and establishing reasonable expectations,and is beneficial to improve postoperative auditory and speech development,so that children can benefit the most.Retrospective studies have shown that there are many factors affecting the effect of Cl in children.These factors could be roughly divided into preoperative factors,implant and surgical factors,postoperative factors and the other factors.Preoperative factors mainly include the cause of hearing loss,the duration and extent of hearing loss,the age at the time of cochlear implantation,the use of hearing aids,the cochlear anatomical characteristics Implant and surgical factors include the type of CI,electrode insertion approach,intracochlear electrode position,the side accepting Cl and residual hearing reservation.Postoperative factors include auditory patterns,the duration with CI,rehabilitation modes,and educational methods.The other factors include the parents' educational degrees,the economic status of the family and society,and the parental expectations.Although there were many studies on the influencing factors,most of them were the discussion of a few factors,or only the influence of these factors on the auditory and speech functions at a certain point in time.However,due to differences in individual and external environment,the factors affecting the postoperative effect of CI are often complex and variable.In order to better understand the development of auditory and speech functions after cochlear implantation and the influence of different factors on them,this study analyzed the developmental trajectory of auditory and speech functions postoperative of CIs in children with prelingual hearing loss.At the same time,the factors affecting the development of postoperative auditory and speech functions were analyzed such as the age at the time of cochlear implantation,the use of hearing aids and the guardian information,etc.The electrode inserting approach and the intracochlear electrode position are also important factors affecting the effect of CIs.However,due to the limitations of imaging technology,the electrodes could not be visually observed after been inserted into the cochlea,which made it impossible to accurately identify and measure the position of the electrodes in the cochlea and to clarify the injury in the cochlea.This limited us to explore the advantages and disadvantages of different inserting approaches and the influence of the electrodes position and the intracochlear injury on the postoperative effect.Although X-ray or multi-slice spiral CT has been used to observe and study the postoperative intracochlear electrodes in previous studies,the operation was complicated and the accuracy was poor,which made their application difficult to promote.The emergence of cone beam computed tomography(CBCT)provides a new method to solve this problem.CBCT has many advantages,such as less radiation dose,high imaging resolution,less metal artifacts,short scanning time,easy to operate and low cost.At present,this technology has been widely used in Stomatology.Only a few scholars around the world have reported the application of CBCT in Otology.Previous studies have confirmed that CBCT could clearly display the intracochlear structure and accurately determine the electrode position and the injury in the cochlea.It was also used by a few scholars to measure the cochlear length and the length of the electrode inserted into the cochlea.The method has been considered to be simple and accurate.On these basis,our study used CBCT to observe the distribution of electrodes in the cochlea and the intracochlear injury in the children with CIs,and to measure the parameters of the electrode position.It provides important reference for the application of CBCT in the field of CI and has important clinical significance.In addition,although the surgery of CI has been relatively mature,how to ensure accurate insertion of the electrodes into the scala tympani and avoid injury to the intracochlear structure to improve postoperative effects and reserve residual hearing is still a major concern for surgeons.Among the factors that determine whether the electrodes can be smoothly inserted into the scala tympani and reduce the injury to intracochlear structure,the characteristics of the electrode arrays are particularly important.Therefore,many scholars are working on the improvement of the electrode properties.At present,the electrode arrays of CIs are mainly curved or soft,which greatly increases the probability of the electrodes being inserted into the scala tympani and significantly reduces the risk of injury to the intracochlear structure.Despite this,the advantages and disadvantages of different electrode inserting approaches in improving the accuracy of the electrodes inserted into scala tympani and reducing the injury of intracochlear structure are still controversial.For this reason,our study used CBCT to observe and analyze the effects of different insertion approaches on the electrodes position in the cochlea and the injury of the cochlear structure,in order to clarify the influence of different inserting approaches on the postoperative electrodes position.At the same time,it will provide reference for exploring the influence mechanism of different inserting approaches on the reservation of residual hearing and the development of auditory and speech functions after cochlear implantation.The study consists of three parts,as follows:Part ?.Analysis of the developmental trajectory and influencing factors of auditory and speech functions after cochlear implantation in young childrenObjective:The individual differences and many external factors have different effects on the children with cochlear implants(CIs).To study the developmental trajectory of postoperative auditory and speech functions and the influence of various factors on postoperative rehabilitation have important reference and guiding significance for promoting the application of Cl in deaf people and exerting its maximum effect.Materials and Methods:The children with CIs who were trained in the Ruifeng Speech and Hearing Rehabilitation Center in Jinan,Shandong Province from June 2016 to June 2019 were followed up.The recognition rates of closed monosyllables and disyllables,the closd average language age,categories of auditory performance(CAP)and speech intelligibility rating(SIR)were tested and evaluated at 0,1,3,6,12 and 24 months of rehabilitation.The results were statistically processed using SPSS 23.0.Results:A total of 49 children were followed up for 1 year,29 children for 2 years.Among the 49 children,36 were male and 13 were female.The age at the time of cochlear implantation was 10 to 68 months(median age,15 months).The recognition rates of closed monosyllables and disyllables,the closed average language age,CAP and SIR of the children gradually increased with the prolongation of rehabilitation,and the greatest increase was achieved within 12 months of rehabilitation,especially within 6 months.The age of cochlear implantation,the degree of guardian education,the use of hearing aids before surgery had influence on the recognition rates of closed monosyllables and disyllables,and CAP.The younger the age at the time of cochlear implantation,the use of hearing aids before surgery and the higher degree of guardian education,the better development of auditory function.In addition,the mother as a guardian could make the recognition rate of closed monosyllables better.The use of hearing aids before surgery and the younger of cochlear implantation were able to obtain higher closed average language age and SIR.The two speech function indicators were relatively poor in the children whose degree of guardian education were primary and high school.Conclusions and significance:The auditory and speech functions of young prelingual children after cochlear implantation increased significantly with the prolongation of rehabilitation.The early stage of postoperative rehabilitation is a critical period of auditory and speech functions development,and is affected by many factors.The age at the time of cochlear implantation and the use of hearing aids before surgery are still important factors influencing the postoperative effect.In addition,the guardians and their educational level also have impacts on postoperative auditory and speech functions development.In clinical and rehabilitation work,we should combine the effects of various factors in order to more accurately predict the effect of CI and develop an individualized rehabilitation program.Part ?.Evaluation of electrode position after cochlear implantation by cone beam computed tomographyObjective:Cochlear implant(CI)could not be directly observed after being inserted into the patients' cochlea.Previously,there was a lack of a simple and accurate method for assessing the position of the electrodes in the cochlea and the injury of the cochlear structure.In this study,we used cone beam computed tomography(CBCT)to observe the distribution of electrodes in the cochlea after cochlear implantation,then provided a reference for the clinical application of CBCT to evaluate the electrodes position.Materials and Methods:Twenty-five children with CIs and CBCT examinations in the Department of Otorhinolaryngology Head and Neck Surgery from the Second Hospital of Shandong University between January 2016 and December 2017 were selected.There were 15 males(17 ears)and 10 females(10 ears).The age ranged from 0.5 to 7.0 years,with a median age of 1.6 years.23 patients with unilateral implantation and 2 patients with bilateral implantation.The implants were all Med-El standard 12-electrode contact arrays.The CBCT was used to determine the position of the electrode in the cochlea,the distance between electrode contacts and modiolus,and intracochlear insertion length of the electrode arrays.SPSS Statistics,version 22.0 was used for data processing and statistical analysis.Results:CBCT images could clearly demonstrate the structure of round window,oval window,modiolus,osseous cochlear duct,osseous spiral lamina,electrodes and so on.The electrode arrays of all the children were fully implanted into the cochlea.26 of the electrode arrays were located in the scala tympani and 1 of them was inserted into the scala vestibular.The mean intracochlear insertion length of the electrode arrays was 30.23(95%CI,30.04-30.71)mm.The distance between electrode contacts and modiolus gradually increased at the 1-4th electrode contacts and reached the maximum at the 4th electrode contacts with an average of 1.10 mm(95%CI,1.02 to 1.1 8 mm),and then gradually decreased from the 5th electrode contacts.Conclusions and Significance:CBCT can clearly show the electrode position and cochlear fine structures after cochlear implantation,and measure the relevant parameters.It can be used for accurate assessment of electrodes position after clinical cochlear implantation.Part ?.Comparison of electrode position between round window and cochleostomy inserting approaches among young childrenObjective:The electrode insertion approach is one of the important factors affecting the postoperative effect of cochlear implant(CI).As the two most commonly used approaches for CIs,the round window insertion(RWI)and cochleostomy are still controversial about which approach is optimal.The lack of visual observation methods made it difficult to compare the electrodes position between them.This study evaluated and compared the electrode position between RWI and cochleostomy approaches for CI among young children in order to clarify the advantages and disadvantages of the two appraoches.Materials and Methods:24 patients(Sixteen male,eight female)accepting CI and temporal cone-beam computed tomography(CBCT)scan post-operation in our hospital from January 2016 to July 2017 were analyzed retrospectively.The age ranged from 0.8 to 7.0 years,with a median age of 2.0 years.There were 2 patients with bilateral implantation through round window.Operative notes and images were used to identify the surgical technique.Mainly depending on the round window exposure,15 cochleae were performed with RWI and 11 performed with cochleostomy.Results:The CBCT images showed that all the electrode arrays were located in scala tympani.There were no significantly statistical differences in the distance between electrode contacts and modiolus(EMI),intracochlear insertion length and the angle of electrode arrays at the insertion site of the cochlea.Conclusions and Significance:Both approaches could insert electrodes into scala tympani satisfactorily.As electrodes and cochlear structure could be clearly visualized and accurately measured,CBCT can be used as a new method to compare the RWI and cochleostomy. |
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