Introduction
Patients with severe or profound hearing loss have an increased risk of dementia, disability and depression.Reference Amieva, Ouvrard, Meillon, Rullier and Dartigues1 Cochlear implant surgery is a transformative surgical intervention for patients with severe or profound hearing loss who do not gain sufficient benefit from hearing aids. In such patients, cochlear implants can significantly improve speech perception, communication, relationships and quality of life.Reference Francis, Chee, Yeagle, Cheng and Niparko2
Cochlear implant surgery is routinely performed under general anaesthesia (GA). In recent years, local anaesthesia (LA) with conscious sedation has been shown to be a safe and feasible alternative to GA,Reference Hamerschmidt, Moreira, Wiemes, Tenório and Tĝmbara3–Reference Vincenti, Plantone, Ciavarro, Lusetti, Bartoli and Di Lella9 and is predominantly offered to those deemed medically unfit for a GA, or to older adult patients who are postulated to have a lower risk of post-operative cognitive decline with sedation or regional anaesthesia as compared to GA.Reference Mason, Noel-Storr and Ritchie10 Techniques for cochlear implant surgery performed under LA described in the literature vary in detail, and predominantly focus on case reports, and single-surgeon and single-centre experiences.Reference Djalilian, Roy, Benson, Regala, McDonald and Leman11–Reference Connors, Deep, Huncke and Roland17
We explored the national experience of UK surgeons using this challenging surgical technique, with the goal of providing consensus recommendations. Our study aimed to summarise the UK experience of performing cochlear implant surgery under LA, with a focus on three key areas: common challenges encountered, recommendations on how to overcome these, and patient selection for cochlear implantation under LA.
Materials and methods
Cochlear implant surgeons from across the UK were invited to take part via e-mail invitations disseminated through the British Cochlear Implant Group network. Surgeons were asked whether they undertake cochlear implant surgery under LA, and those who did were subsequently invited to take part in our study.
The first author (RA) interviewed respondents virtually via the Zoom video communication platform, using a mix of open-ended and focused questions to explore each of the three key areas: common challenges encountered; recommendations on how to overcome these expected challenges, with tips for surgeons newly looking to incorporate cochlear implant surgery performed under LA in their practice; and which patients should be offered cochlear implant surgery under LA. Interviews were recorded, transcribed and thematically analysed.
Of note, for this project, we initially considered seeking data from anaesthetists and patients regarding their experiences of cochlear implantation performed under LA; however, given the rich data gathered from surgeons alone, this study focused solely on presenting a nationwide UK surgeon experience of cochlear implantation performed under LA.
Results
Ten UK surgeons were interviewed virtually, with a mean interview duration of 25 minutes. The mean number of cochlear implantation procedures performed under LA by the surgeons interviewed in our study was 10 (range, 2–35 procedures).
All surgeons used a posterior tympanotomy approach and round window electrode insertion. Only two surgeons (20 per cent) used conscious sedation. The LA agents of choice included lidocaine with adrenaline, bupivacaine, and levobupivacaine with or without adrenaline. Nine surgeons (90 per cent) opted not to use a facial nerve monitor, citing reasons such as painful facial contractions when using the facial nerve stimulator or pain when inserting the facial electrodes.
Common challenges
Common pre-operative challenges encountered included patient, anaesthetist and nursing staff expectations as potential barriers to performing cochlear implantation under LA. Similarly, a lack of personal surgical experience and confidence contributed to surgeon hesitancy.
Intra-operatively, difficulty achieving co-operative sedation was a challenge for one surgeon, who described a patient moving suddenly whilst he drilled close to the facial nerve. Most surgeons interviewed did not use sedation, citing similar concerns. Several surgeons discussed the potential of dexmedetomidine, commonly used in the USA for cochlear implantation procedures under LAReference Connors, Deep, Huncke and Roland17 but limited to intensive care unit settings in the UK.
Managing intra-operative patient pain was a common challenge. One surgeon described how their patient experienced severe pain when drilling through bone that is normally insensate. Another struggled with managing their patient's pain as a result of the scrub nurse's unfamiliarity with using topical LA. Several surgeons sought advice from more experienced colleagues, and adopted the use of topical LA into the mastoid in their technique. Patient discomfort from vertigo was highlighted as a challenge, especially at the stage of irrigating the mastoid. Patient discomfort with the use of suction in the presence of good low-frequency hearing was also reported. Other challenges included difficulties of patients remaining still during the procedure.
A key challenge highlighted by all surgeons interviewed was establishing clear intra-operative communication with the patient. Operating on patients with visual impairment restricted the use of written communication during surgery. Maintaining communication with the patient also ‘tied up’ an extra member of staff during the procedure. The challenge of involving trainees was emphasised as a drawback to making cochlear implant surgery performed under LA the routine practice.
Tips on overcoming these challenges
All surgeons suggested methods they had utilised and developed in their practice to overcome the above-mentioned challenges. We present these tips and recommendations in Table 1.
Tips and recommendations by UK surgeons to overcome common challenges encountered in CI surgery performed under LA
CI = cochlear implant; LA = local anaesthesia; GA = general anaesthesia; WHO = World Health Organization
Patient selection
We explored surgeons’ perspectives on the selection of patients for cochlear implant surgery performed under LA. Six surgeons (60 per cent) felt that cochlear implant surgery under LA should be routinely offered to all eligible candidates, emphasising the importance of ensuring favourable anatomy confirmed by computed tomography scans, rather than surgically complex cases. Others focused on choosing patients who would tolerate being awake through major surgery. It was also mentioned that patients who are significantly obese, or who have restricted neck mobility or significant kyphosis, may find intra-operative positioning uncomfortable and therefore might be better suited to having the surgery under GA.
All surgeons highlighted the advantages of performing cochlear implant surgery under LA, including the avoidance of: risks associated with GA and coronavirus disease 2019; the potential risk of post-operative cognitive decline in older adult patients; the risk of deep venous thrombosis; and longer post-operative hospital stay following GA. One surgeon performed cochlear implant surgery under LA on a pregnant patient, in her third trimester, to avoid any drug-induced complications; she would have been unsuitable for cochlear implant surgery under GA during pregnancy.
Despite these advantages, some surgeons expressed hesitancy regarding cochlear implant surgery performed under LA as the routine practice. Some surgeons felt that cochlear implant surgery performed under LA should be offered only to those deemed medically unfit for GA. Two surgeons felt that they would likely offer cochlear implant surgery under LA to adults above a certain age, to minimise the risk of post-operative cognitive decline. It was also emphasised that surgery performed under LA also carries risk. Therefore, a thorough pre-operative clinical and anaesthetic assessment of the patient was recommended, to guide the decision-making process for both the patient and surgeon.
Discussion
This work suggests that, in the hands of experienced surgeons, cochlear implant surgery performed under LA can potentially be offered to all patients eligible for a cochlear implant, with a preference for those with favourable anatomy. We suggest techniques and tips to optimise the patient and surgeon experience of cochlear implantation performed under LA, shedding light on common pitfalls and challenges.
Our cohort of UK surgeons provided advice on how to manage patient, personal and staff expectations pre-operatively, as well as providing recommendations to optimise intra-operative communication and patient comfort during surgery. This is the first time that these key aspects of cochlear implant surgery under LA have been explored and presented in depth (Table 1).
A limitation of this work is that several of the surgeons were on the learning curve; however, this also meant they were able to provide invaluable insight from recent experiences.
Most UK cochlear implant surgeons prefer not to use sedation when performing cochlear implant surgery under LA. This contrasts with protocols described in the world literature, with US surgeons using dexmedetomidineReference Djalilian, Roy, Benson, Regala, McDonald and Leman11,Reference Deep, Connors and Roland15,Reference Connors, Deep, Huncke and Roland17 and those in the EU using propofol and/or midazolam for conscious sedation.Reference Alzahrani, Martin, Bobillier, Robier and Lescanne4,Reference Dietz, Wustefeld, Niskanen and Lopponen14 Concerns raised by our UK cohort of surgeons primarily surrounded the risk of unpredictable sedation. Dexmedetomidine, not currently licensed for operating theatre use in the UK, has been shown to achieve co-operative sedation,Reference Bajwa and Kulshrestha18 with better arousable sedation compared to propofol,Reference Bruggen, Ceuppens, Leliveld, Stronks and Huygen19 and associated with better analgesia and post-operative pain scoresReference Bingol Tanriverdi, Koceroglu, Devrim and Gura Celik20 and fewer respiratory adverse events.Reference Goettel, Bharadwaj, Venkatraghavan, Mehta, Bernstein and Manninen21
Our cohort of surgeons recommended various techniques to control intra-operative pain, including advice on achieving adequate LA at the start of the procedure with a wide range of possible LA agents. Various methods to control pain during surgery were also recommended. Most correlate with techniques mentioned in the literature, such as the use of pledgets saturated with lidocaine and the use of intravenous analgesia.Reference Mistry, Carr, Martin, Strachan, Raine and Fyrmpas6,Reference Shabashev, Fouad, Huncke and Roland7,Reference Connors, Deep, Huncke and Roland17 Other recommended techniques include introducing topical LA through the posterior tympanotomy into the middle ear, being mindful of potentially precipitating nystagmus and vertigo. One surgeon noted significant discomfort for a patient when using suction in the middle ear, postulating whether residual hearing played a role in the patient's experience of cochlear implantation under LA. This has not been previously explored in the literature.
All surgeons extolled the advantages of performing surgery under LA. As well as avoiding the risks associated with GA, other benefits include decreased surgery and anaesthesia time, reduced drug costs and shorter length of hospital stay.Reference Shabashev, Fouad, Huncke and Roland7
• Cochlear implantation performed under local anaesthesia (LA) is an increasingly accepted technique worldwide
• The literature to date includes only single-surgeon and single-centre experiences
• Cochlear implantation under LA can potentially be offered to all eligible adult patients with favourable anatomy, not just those for whom general anaesthesia is a risk
• Common challenges include: managing patient, surgeon, and staff expectations; optimising communication; patient comfort and position; and minimising pain and vertigo
• There is reluctance to use conscious sedation because of potential unpredictability, but this could be circumvented using dexmedetomidine
• A perceived disadvantage of cochlear implantation under LA is the limited role of trainee input
The main drawback to cochlear implantation performed under LA was the challenge of involving trainees; in contrast, cochlear implantation performed under GA is a useful training case in the presence of healthy temporal bones and normal middle- and inner-ear anatomy.
Conclusion
This is the first time that a national experience of cochlear implantation under LA has been studied, and key aspects to improve surgeon and patient experience have been explored in depth. We hope this work is useful for surgeons newly looking to incorporate cochlear implant surgery under LA in their practice.
Acknowledgements
We thank Professor Chris Raine, Mr Joe Toner, Miss Emma Stapleton, Mr Peter Wardrop, Mr Simon Freeman, Mr Samuel MacKeith, Mr Richard Irving, Mr Stephen Broomfield, Mr Philip Robinson and Professor Simon Lloyd for kindly sharing their experience and wisdom. We would also like to thank Professor Helen Cullington and the British Cochlear Implant Group for the use of their professional network to identify UK surgeons with experience of performing cochlear implant surgery under local anaesthesia. This research was supported by the National Institute for Health Research Manchester Biomedical Research Centre.
Data availability statement
The data are available from the first author on request.
Competing interests
None declared.
