|Year : 2022 | Volume
| Issue : 3 | Page : 244-248
Cochlear implantations in Jordan: Retrospective analysis of post-operative complications
Nemer AlKhtoum1, Shawkat AlTamimi2, Osama Alalwan1, Abedlrazzaq Alrfooh1, Motasem AlKrymeen1
1 Department of Otolaryngology, Royal Medical Services, Amman, Jordan
2 Department of Otolaryngology, Balqa' Applied University, Balqa, Jordan
|Date of Submission||16-May-2022|
|Date of Decision||20-Jun-2022|
|Date of Acceptance||22-Jun-2022|
|Date of Web Publication||22-Jul-2022|
Department of Otolaryngology, Royal Medical Services, Amman
Source of Support: None, Conflict of Interest: None
Aims: This study aims to carry out a retrospective analysis of demographic information and post-operative complications with special emphasis on complications related to the soft tissue over the implanted device in patients who underwent cochlear implantation. Settings and Design: Retrospective study. Patients and Methods: We conducted a retrospective review of 840 patients who had cochlear implants at our centre during the period between March 2010 and November 2020. The patients' demographic details and complications related to the soft tissue over the implanted device were analysed. Statistical Analysis Used: SPSS software version 12. Results: In total, 380 (45.2%) patients were male and 460 (54.8%) were female. The age of patients at the time of surgery ranged between 7 months and 68 years and the mean age was 4.64 ± 2.91 years. The majority of patients underwent unilateral cochlear implantation (837 patients), with only three patients receiving a bilateral implant. There were a total of 19 implanted patients who developed complications related to the soft tissue around the implanted device, with an incidence rate of 2.3%. Haematoma was the most commonly encountered complication and other complications were: seroma, wound infection, abscess formation and flap necrosis. Conclusions: Cochlear implantation is considered to be a reliable and safe surgical procedure for the rehabilitation of deaf patients. Complications can be avoided by proper patient preparation, appropriate incision and flap design, rigorous surgical techniques and periodic post-operative follow-up to detect and manage any complications early.
Keywords: Cochlear implantation, complications, flap necrosis, implanted device, soft tissue
|How to cite this article:|
AlKhtoum N, AlTamimi S, Alalwan O, Alrfooh A, AlKrymeen M. Cochlear implantations in Jordan: Retrospective analysis of post-operative complications. Niger Postgrad Med J 2022;29:244-8
|How to cite this URL:|
AlKhtoum N, AlTamimi S, Alalwan O, Alrfooh A, AlKrymeen M. Cochlear implantations in Jordan: Retrospective analysis of post-operative complications. Niger Postgrad Med J [serial online] 2022 [cited 2022 Aug 13];29:244-8. Available from: https://www.npmj.org/text.asp?2022/29/3/244/351718
| Introduction|| |
Cochlear implantation is considered to be one of the great achievements of modern medicine, restoring the function of hearing for both children and adults with severe to profound deafness who finds traditional hearing aids ineffective.
The cochlear implant is a small electronic device that is used to stimulate the auditory nerve directly through an array of electrodes and to translate acoustic signal into electric stimulation.
It is important that the stimulation threshold is set accurately and the implant is set at comfortable levels to enable better functioning of the device to provide these patients with a greater access to sound and improvement in their auditory abilities, understanding of speech and linguistic development.
The surgical technique used varies, but the classic procedure involves mastoidectomy with the formation of distinct skin and soft-tissue flaps over the mastoidectomy site, as well as a soft tissue envelope enclosing the implanted device, opening the facial recess, cochleostomy or round window route and placement of an array of electrodes through the cochlea's basal turn.
Since cochlear implantation is considered a lifetime implanted device and is covered by the overlying skin and soft tissues, which are all strongly adhered to the underlying bone of the skull, the procedure has a peculiar set of complications. These complications are associated with either the complexity of the operation or implantation of a deeply placed foreign body on the scalp or device failure.
The complications can be classified as an immediate or delayed according to their timing, or they can be considered minor or major according to their severity. Understanding the problems associated with this procedure is essential.
Soft-tissue complications post-cochlear implantations are considered to be rare and treatable. The management varies from conservative treatment to device explantation.
In this study, we reviewed the demographic information and post-operative complications with special emphasis on complications related to the soft tissue over the implanted device.
| Patients and Methods|| |
We performed a retrospective analysis of 840 patients who underwent cochlear implantation at our centre during the period between March 2010 and November 2020.
Our faculty's ethical committee authorised the study (2021–2015]. Due to the retrospective basis of the study, the board waived the requirement for written informed consent.
All patients were diagnosed with bilateral severe to profound sensorineural hearing loss by detailed history taking in addition to complete ear, nose, throat and neurological examination.
Audiological tests included pure tone audiometry with tone decay, aided audiometry, auditory brainstem response test, otoacoustic emission and speech discrimination test. Pre-operative radiological evaluation by the mean of computed tomography scan and magnetic resonance imaging of temporal bone and brain were performed in all patients.
Majority of implantations were performed on one side. All operative procedures were performed by one of the cochlear implant surgeons, who are well trained to perform such procedures using a standardised surgical technique.
Over the years, there have been some changes to the soft-tissue approach of the procedure, which has been influenced by technological advancements in implant receivers. Initially, when we started the cochlear implant programme in 2002, we used an extended post-auricular S-shaped skin incision and we placed the receiver-stimulator of the implant in the bony bed, which is later appropriately fixed using sutures on both sides of the bony bed. Later, since 2008, a minimal C-shaped post-auricular incision and flap approach with a tight subperiosteal pocket was used; this approach is used to date. The incision was closed in three sutured layers followed by a compressive mastoid dressing, which was placed and maintained for 1 week.
All patients in this study underwent a minimal C-shaped retroauricular skin incision.
After surgery, patients were kept in the hospital for 48 h. X-ray imaging was routinely conducted to validate the device's electrode array's position. During the hospital stay, a prophylactic broad-spectrum antimicrobial that can pass the blood–brain barrier was given intravenously, the compressive mastoid dressing was changed, and the patient was discharged home with oral antibiotics. On the 10th post-operative day, the wound was examined for any potential complications and the sutures were removed.
Patients were seen at the outpatient clinic 4 weeks after surgery for the first activation of the implanted device.
The patients' demographic details and post-operative complications with special emphasis on complications related to the soft tissue over the implanted device were reviewed.
SPSS 12.0 (SPSS Inc., Chicago, IL, USA) was used for analyses of data.
| Results|| |
The records of 840 patients who were implanted at our centre during the period between March 2010 and November 2020 were reviewed. We followed up all patients for at least 1 year after cochlear implantation.
In total, 380 patients (45.2%) were male and 460 patients (54.8%) were female. The age of patients at the time of surgery ranged between 7 months and 68 years and the mean age of the patients was 4.64 ± 2.91 years.
The youngest age at the time of implantation was 7 months, with only four children being implanted when under 1-year-old. Overall, 612 (72.8%) patients were below 6 years of age.
All patients had bilateral severe to profound sensorineural hearing loss; 720 patients had pre-lingual hearing loss (85.7%), while 120 patients had post-lingual hearing loss (14.3%).
The majority of patients underwent unilateral cochlear implantation (837 patients), with only three patients receiving bilateral implants.
Overall, 805 cases received implantation on the right side (95.8%), while 32 cases had implantation on the left side (3.8%) and three cases on both sides (0.4%).
Regarding the type of device implanted in this study group, the vast majority of implanted devices were MED-EL devices (Med-El Corporation, Innsbruck Austria), accounting for 833 (99.2%) of the implantations. Six cases (0.7%) were implanted with Nucleus devices (Cochlear Corp., Australia) and only one case (0.1%) was implanted with an AB device (Advanced Bionics Corporation, USA) [Table 1].
There were a total of 33 implanted patients who developed complications postoperatively with an incidence rate of 3.9%, from this number we reported 19 patients who developed complications related to the soft tissue around the implanted device, with an incidence rate of 2.3% [Table 2].
The onset of complications ranged from 1 day to 9 years after surgery, with a mean time of 23.4 months.
Wound infection was reported in three cases. They were manifested by swelling and redness of the surgical incision 11 days' postoperatively. Patients were admitted to the hospital and treated with intravenous (IV) antibiotics and daily dressing changes; all recovered without any further intervention.
Nine patients presented with post-operative haematoma above the area of the device, which was manifested by post-auricular tender fluctuant swelling. Five patients developed haematoma 2–3 days' post-surgery, three patients had haematoma 2 weeks after surgery and one patient developed haematoma 6 months following the operation without any history of direct trauma to the site of the device.
Patients were admitted to the hospital and received IV antibiotics, aspiration of haematoma and local mastoid pressure dressings. Patients were discharged from the hospital when the haematoma was completely resolved; the duration of hospitalisation ranged between 3 and 7 days.
Seroma was observed in four patients, who developed local painless swelling around the site of the implant years after operation; the swelling was soft and fluctuant without any tenderness. Aspiration revealed a yellowish fluid which was shown by laboratory analysis to be a serious fluid with negative pus cells. Culture of the fluid from all patients revealed no bacterial growth. Patients were treated as outpatients by mean of aspiration under aseptic conditions in addition to pressure dressing and antibiotics, which was effective in all cases.
We reported two patients who presented with fever, swelling, redness and tenderness around the implanted device. The treatment protocol for those patients was hospitalisation, incision and drainage of purulent fluid and pressure dressing, in addition to systemic antibiotics and symptomatic treatments. The abscess was resolved in all patients with this protocol.
Flap necrosis occurred in one patient. This patient developed delayed-onset flap necrosis 9 years after cochlear implantation, which required debridement and removal of the device in addition to systemic antibiotics and implantation of a new device 3 months later.
Transient facial nerve paralysis
Two patients developed temporary facial paralysis, one of them 1st and the other one in the 2nd post-operative day. They were treated with systemic steroids and both of them recovered completely after 1 week.
Three patients complained of transient vertigo and vomiting within the 1st post-operative day and were managed conservatively. These symptoms resolved completely after 5 days.
Chorda tympani nerve injury
Three patients presented with taste disturbances and paraesthesia of the tongue which was managed conservatively.
Facial nerve stimulation
One patient with a malformed inner ear, presented with facial twitches on the operated side 3 months after implantation. He was managed by programming and by deactivating the offending electrode.
Device failure was reported in one patient due to head trauma which was confirmed by dysfunction of impedance measurements. The patient underwent re-implantation with new device.
Intra operative cerebrospinal fluid gusher
Four children with Mondini deformity developed intraoperative cerebrospinal fluid (CSF) gusher. This gusher was controlled by sealing the cochleostomy with pieces of tissue and muscle. None of them had post-operative CSF leakage.
| Discussion|| |
A cochlear implant is considered to be a safe and effective procedure for profoundly deaf patients. It has enabled this category of patients to continue communicating with others using speech by providing them with sufficient hearing.,
With the advancement of technology and surgical equipment and techniques, the possible complications of this procedure have progressively declined. Surgical complications are rare in the hands of experienced surgeons, but can still occur.
Soft-tissue complications following cochlear implant surgery are associated with inflammation and infection of the soft tissue around the internal receiver of the implant. The most frequently reported complications not related to the implanted device are flap necrosis, infection, wound dehiscence leading to device explantation., In our study, the incidence of soft-tissue complications was 2.3%, while rates of complications reported in the literature range from 0.06% to 10%.,, Although this incidence is not considered to be high, the management of complications related to the soft tissue around the implanted device remains challenging.
Haematoma over the area of the device was the most commonly encountered complication in our study, reported in nine cases (1.1%). This is comparable to the incidence of flap haematoma in the literature, which ranges from 0.4% to 3.7%.,, This complication usually developed 1 to 2 days' post-surgery. However, we reported a case that developed haematoma 6 months after surgery without any history of trauma. This delayed-onset haematoma was reported by previous studies., We managed this complication using IV antibiotics, aspiration of the haematoma and local mastoid pressure dressings, which is the same protocol advocated by other studies.,,, Wound infection is one of the complications that is considered to be a major concern by the cochlear implant team. According to the literature, the rate of wound infection ranges from 1.7% to16.6%.,, In our study, the overall rate of skin flap infection was 0.4%. All patients were managed successfully with IV antibiotics and daily wound dressing.
In our data, seroma was observed in four patients, who developed local painless swelling around the site of the implants years after operation, which was soft and fluctuant without any tenderness. The mechanisms leading to seroma formation remain unclear. Some studies reported that the silicone rubber of the implanted device results in delayed allergy reactions, which leads to seroma formation. All cases were treated as outpatients by mean of aspiration under aseptic conditions in addition to pressure dressing and antibiotics, which was effective in all cases. Several studies have reported a low incidence of delayed seroma in both children and adults, years after cochlear implantation.,
In two patients, abscesses around the implanted device developed, which manifested by fever, swelling, redness and tenderness. All abscesses were resolved by drainage in addition to pressure dressing and systemic antibiotics.
We reported one case that developed delayed-onset flap necrosis 9 years after cochlear implantation, which required debridement and explantation of the device in addition to systemic antibiotics and later reimplantation. Several studies reported the treatment of skin flap necrosis by debridement of necrotic tissue and skin rotation flaps with device removal.,
In the present study, we performed a retrospective analysis of post-operative complications in 840 cochlear implant recipients, in addition to the soft-tissue complications; we reported also other complications intraoperatively and postoperatively.
In our study, two patients developed temporary facial paralysis (0.2%), which is comparable to the rate reported in the literature (0.7%).,,, These two patients were treated with systemic steroids and both of them recovered completely after 1 week. Because of abnormal anatomical variations, the risk of facial nerve injury is higher in patients with inner ear malformations. The low rate of facial paralysis (0.2%) in our study may be attributed the routine use of Facial nerve monitoring in all cases during surgery in order to avoid injury to the facial nerve.
Another complication related to facial nerve and was found in one patient in our study is facial nerve stimulation (0.1%). Which was managed by re-programming; this condition was reported in the literature., The transmission of electric charge through the electrode which can cause symptoms by spreading to the neighbouring facial nerve is the suggested explanation of facial nerve stimulation post-cochlear implantation. It is seen mostly in patients with Cochlear abnormalities, patients with fractured temporal bone and patients with otosclerosis.
Taste disturbances and paraesthesia of the tongue due to chorda tympani injury were seen in three patients (0.3%) which was managed conservatively. The low incidence reported here could be attributed to the fact that the bulk of our cases were children who found difficulty in expressing this problem. Post-operative chorda tympani dysfunction has been observed in other studies with different rates depending on the age and number of studied patients.,,,,,
Transient post-operative vertigo and vomiting were seen in three patients (0.3%) who were managed conservatively. In the literature, the estimated incidence is ranging from 9.5% to 49%,,,, again we reported a low rate of vertigo compared to other studies because the bulk of our patients were pre-lingual children who are unable to express this problem.
Children are assumed to be at a higher risk of device failure, presumably due to the higher risk of implant trauma while playing. However, in our study, we reported one case (0.3%) due to head trauma which was confirmed by dysfunction of impedance measurements. The patient underwent removal of the device and re-implantation with new device. Our results follow those reported in the literature.
Intraoperative CSF gusher was observed in four children with Mondini deformity. This gusher was controlled by sealing the cochleostomy with pieces of tissue and muscle. None of them had post-operative CSF leakage. This complication is reported to be more common in patients with cochlea vestibular congenital anomalies.,,
The limitations in our study, we did not compare these complications between patients who had the current C-shaped incision and the older large S-shaped incision due to insufficient data regarding this group. For this reason, we studied the complications in patients who had minimal C-shaped retroauricular skin incision.
| Conclusions|| |
Cochlear implantation is considered to be a reliable and safe surgical procedure for the rehabilitation of deaf patients. In the hands of an experienced surgeon, the rate of complications is low and the majority of these complications can be conservatively managed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2]