Intraoperative assessment of microimplantation-induced acute brain inflammation with titanium oxynitride-based plasmonic biosensor.

Implantable devices for brain-machine interfaces and managing neurological disorders have experienced rapid growth in recent years. Although functional implants offer significant benefits, issues related to transient trauma and long-term biocompatibility and safety are of significant concern. Acute inflammatory reaction in the brain tissue caused by microimplants is known to be an issue but remains poorly studied. This study presents the use of titanium oxynitride (TiNO) nanofilm with defined surface plasmon resonance (SPR) properties for point-of-care characterizing of acute inflammatory responses during robot-controlled micro-neuro-implantation. By leveraging surface-enriched oxynitride, TiNO nanofilms can be biomolecular-functionalized through silanization. This label-free TiNO-SPR biosensor exhibits a high sensitivity toward the inflammatory cytokine interleukin-6 with a detection limit down to 6.3 fg ml-1 and a short assay time of 25 min. Additionally, intraoperative monitoring of acute inflammatory responses during microelectrode implantation in the mice brain has been accomplished using the TiNO-SPR biosensors. Through intraoperative cerebrospinal fluid sampling and point-of-care plasmonic biosensing, the rhythm of acute inflammatory responses induced by the robot-controlled brain microelectrodes implantation has been successfully depicted, offering insights into intraoperative safety assessment of invasive brain-machine interfaces.

Vasogenic oedema during stereoelectroencephalography: intracranial pattern and late-onset clinical repercussion.

In patients suffering from focal drug-resistant epilepsy, intracranial explorations are the gold standard for identifying the epileptogenic zone and evaluating the possibility of a surgical resection. Amongst them, stereoelectroencephalography (SEEG), using depth electrodes, is a safe procedure. However, complications occur on average in 2% of cases, notably haemorrhages or infections. Vasogenic cerebral oedema constitutes a rarely reported complication. Amongst the 85 patients explored with SEEG between January 2017 and September 2023, three had a clinically and electrophysiologically relevant vasogenic cerebral oedema. In these three patients, the surgical procedure was uneventful. In all three as well, electrodes exploring areas away from the epileptogenic zone recorded some unexpected focal delta slowing with clinically asymptomatic superimposed discharges, a pattern so far only reported in cases of bleeding. Moreover, one patient experienced confusion 10 days after explantation. Post-explantation magnetic resonance imaging showed, in all three patients, a vasogenic oedema that fully resolved a few months later. We did not identify any contributing factors, and there were no particularities concerning the number of electrodes, their implantation site or the recording duration. Focal delta slowing and rhythmic discharges during SEEG can indicate a vasogenic oedema. Clinical consequences can occur after explantation. Evolution is favourable but this misleading pattern must be identified.

Comprehensive proteomic analysis of the differential expression of 62 proteins following intracortical microelectrode implantation.

Intracortical microelectrodes (IMEs) are devices designed to be implanted into the cerebral cortex for various neuroscience and neuro-engineering applications. A critical feature of IMEs is their ability to detect neural activity from individual neurons. Currently, IMEs are limited by chronic failure, largely considered to be caused by the prolonged neuroinflammatory response to the implanted devices. Over the past few years, the characterization of the neuroinflammatory response has grown in sophistication, with the most recent advances focusing on mRNA expression following IME implantation. While gene expression studies increase our broad understanding of the relationship between IMEs and cortical tissue, advanced proteomic techniques have not been reported. Proteomic evaluation is necessary to describe the diverse changes in protein expression specific to neuroinflammation, neurodegeneration, or tissue and cellular viability, which could lead to the further development of targeted intervention strategies designed to improve IME functionality. In this study, we have characterized the expression of 62 proteins within 180 µm of the IME implant site at 4-, 8-, and 16-weeks post-implantation. We identified potential targets for immunotherapies, as well as key pathways that contribute to neuronal dieback around the IME implant.

Vascular imaging for Stereoelectroencephalography: A safety and planning study.

BACKGROUND: Stereoelectroencephalography (SEEG) is a procedure used to localize the epileptogenic zone in patients with medically refractory epilepsy, involving the stereotactic implantation of electrodes into brain parenchyma. Magnetic Resonance Imaging (MRI), Digital Subtraction Angiography, and Computed Tomography have been used preoperatively to prevent Intracranial Hemorrhage (ICH) by identifying electrode-vessel conflicts (EVC's) on planned electrode trajectories. There is variation in the use of Digital Subtraction Angiography and non-invasive sequences for vascular planning. Digital Subtraction Angiography provides high spatial resolution, but carries risks of arterial dissection, groin and retroperitoneal hematoma, and a 0.5-1.9% risk of stroke. Our group has incorporated Intravenous Cone Beam Computed Tomography (CBCT A/V) Brain into our SEEG workflow, given its effective implementation in other neurosurgical domains. Primary aims include validating the safety of our CBCT A/V sequence for SEEG planning and determining if CBCT A/V is comparable to other modalities in detecting EVC's. Secondary aims include elucidating the relationship of conflicting vessel calibre with ICH incidence in SEEG using CBCT A/V imaging. METHODS: A single-center retrospective study was conducted of 20 patients who underwent preoperative CBCT A/V Brain and MRI Brain with gadolinium enhancement, encompassing 273 electrode implantations from August 2020 - July 2023. The incidence and grade of post-implant, post-explant symptomatic ICH and asymptomatic ICH was noted. The total number of EVC's identifiable on MRI and CBCT A/V was recorded, along with average diameter of conflicting vessels. RESULTS: Across 20 patients and 273 implanted electrodes, there were four ICH events, where two were symptomatic and two were asymptomatic. The mean diameter of EVC's across all patients was 1.4 mm (±0.5). A significant difference (P < 0.0001) was observed between the number of EVC's that CBCT A/V could identify (20) compared to MRI (6). Two EVC's were identified in the region of two symptomatic ICH's, with the mean diameter of these conflicted vessels being 1.5 mm (±0.4). The two symptomatic ICH-associated EVC's were observed on CBCT A/V but not MRI. CONCLUSIONS: In our series, CBCT A/V demonstrates an acceptable safety profile for SEEG planning compared to other imaging modalities. CBCT A/V identified significantly more EVC's compared to MRI, including those contributing to transient symptomatic intracranial hemorrhage. A conflicting vessel calibre of less than 1.2 mm on CBCT A/V did not contribute to ICH in our SEEG series.

Glial Response and Neuronal Modulation Induced by Epidural Electrode Implant in the Pilocarpine Mouse Model of Epilepsy.

In animal models of epilepsy, cranial surgery is often required to implant electrodes for electroencephalography (EEG) recording. However, electrode implants can lead to the activation of glial cells and interfere with physiological neuronal activity. In this study, we evaluated the impact of epidural electrode implants in the pilocarpine mouse model of temporal lobe epilepsy. Brain neuroinflammation was assessed 1 and 3 weeks after surgery by cytokines quantification, immunohistochemistry, and western blotting. Moreover, we investigated the effect of pilocarpine, administered two weeks after surgery, on mice mortality rate. The reported results indicate that implanted mice suffer from neuroinflammation, characterized by an early release of pro-inflammatory cytokines, microglia activation, and subsequent astrogliosis, which persists after three weeks. Notably, mice subjected to electrode implants displayed a higher mortality rate following pilocarpine injection 2 weeks after the surgery. Moreover, the analysis of EEGs recorded from implanted mice revealed a high number of single spikes, indicating a possible increased susceptibility to seizures. In conclusion, epidural electrode implant in mice promotes neuroinflammation that could lower the seizure thresholds to pilocarpine and increase the death rate. An improved protocol considering the persistent neuroinflammation induced by electrode implants will address refinement and reduction, two of the 3Rs principles for the ethical use of animals in scientific research.

Device-Related Complications Associated with Cylindrical Lead Spinal Cord Stimulator Implants: A Comprehensive Review.

PURPOSE OF REVIEW: Spinal cord stimulation (SCS) is an increasingly utilized therapy for the treatment of neuropathic pain conditions. Though minimally invasive and reversable, there are several important device-related complications that physicians should be aware of before offering this therapy to patients. The aim of this review is to synthesize recent studies in device-related SCS complications pertaining to cylindrical lead implantation and to discuss etiologies, symptoms and presentations, diagnostic evaluation, clinical implications, and treatment options. RECENT FINDINGS: Device-related complications are more common than biologic complications. Device-related complications covered in this review include lead migration, lead fracture, lead disconnection, generator failure, loss of charge, generator flipping, hardware related pain, and paresthesia intolerance. The use of SCS continues to be an effective option for neuropathic pain conditions. Consideration of complications prior to moving forward with SCS trials and implantation is a vital part of patient management and device selection. Knowledge of these complications can provide physicians and other healthcare professionals the ability to maximize patient outcomes.

Management of Cochlear Implant Electrode Arrays Misplaced in the Internal Auditory Canal: A Systematic Review.

OBJECTIVE: Misplacement of electrode arrays in the internal auditory canal (IAC) presents a unique clinical challenge. Speech recognition is limited for cochlear implant (CI) users with misplaced arrays, and there are risks with revision surgery including facial and/or cochlear nerve injury. DATABASES REVIEWED: PubMed, Embase, and Scopus. METHODS: A literature search was performed from inception to September 2023. The search terms were designed to capture articles on misplaced arrays and the management options. Articles written in English that described cases of array misplacement into the IAC for children and adults were included. The level of evidence was assessed using Oxford Center for Evidence Based Medicine guidelines. Descriptive statistical analyses were performed. RESULTS: Twenty-eight cases of arrays misplaced in the IAC were identified. Thirteen (46%) were patients with incomplete partition type 3 (IP3), and 7 (25%) were patients with common cavity (CC) malformations. Most misplaced arrays were identified postoperatively (19 cases; 68%). Of these cases, 11 (58%) were managed with array removal. No facial nerve injuries were reported with revision surgery. Eight cases (42%) were left in place. Several underwent mapping procedures in an attempt improve the sound quality with the CI. CONCLUSION: Electrode array misplacement in the IAC is a rare complication that reportedly occurs predominately in cases with IP3 and CC malformations. Removal of misplaced arrays from the IAC reportedly has not been associated with facial nerve injuries. Cases identified with IAC misplacement postoperatively can potentially be managed with modified mapping techniques before proceeding with revision surgery.

Recommendations for the Prevention and Management of Deep Brain Stimulation Infections Based on 26-Year Single-Center Experience.

INTRODUCTION: Infections related to deep brain stimulation (DBS) can lead to discontinuation of the treatment and increased morbidity. Various measures of reducing infection rates have been proposed in the literature, but scientific consensus is lacking. The aim of this study was to report a 26-year single center experience of DBS infections and provide recommendations for the prevention and management of them. METHODS: The retrospective analysis consisted of 978 DBS surgeries performed at Oulu University Hospital (OUH) from 1997 to 2022. This included 342 primary or reimplantations of DBS electrodes and 559 primary or reimplantations of implantable pulse generator (IPG). Infections within approximately 1 year after the surgery without secondary cause were considered surgical-site infections (SSIs). χ2 test was used to compare infection rates before and after 2013, when the systematic implementation of infection prevention measures was started. RESULTS: A total of 35 DBS implants were found to be infected. The number of SSIs was 30, of which 29 were originally operated in OUH leading to a center-specific infection rate of 3.1%. Of the SSIs, 17.2% occurred after IPG replacement. Staphylococcus aureus was found in 75.0% of cultures and 32.1% were mixed infections. The treatment of SSIs included aggressive surgical revision combined with cefuroxime and vancomycin antibiotics, as most patients in the initial conservative treatment group eventually required surgical revision. A statistically significant difference in infection rates before and after the implementation of preventative measures was not observed (risk ratio 2.20, 95% confidence interval 0.94-5.75, p = 0.051), despite over two-fold difference in the incidence of SSIs. CONCLUSION: Our findings show that the rates of surgical infections are low in modern DBS, but due to their serious consequences, preventative measures should be implemented. We highlight that mixed infections should be accounted for in the antibiotic selection. Furthermore, our treatment recommendation includes aggressive surgical revision combined with antibiotic treatment.

Changes in hearing function and intracochlear morphology after electrode array insertion in minipigs.

BACKGROUND: In temporal bone specimens from long-term cochlear implant users, foreign body response within the cochlea has been demonstrated. However, how hearing changes after implantation and fibrosis progresses within the cochlea is unknown. OBJECTIVES: To investigate the short-term dynamic changes in hearing and cochlear histopathology in minipigs after electrode array insertion. MATERIAL AND METHODS: Twelve minipigs were selected for electrode array insertion (EAI) and the Control. Hearing tests were performed preoperatively and on 0, 7, 14, and 28 day(s) postoperatively, and cochlear histopathology was performed after the hearing tests on 7, 14, and 28 days after surgery. RESULTS: Electrode array insertion had a significant effect for the frequency range tested (1 kHz-20kHz). Exudation was evident one week after electrode array insertion; at four weeks postoperatively, a fibrous sheath formed around the electrode. At each time point, the endolymphatic hydrops was found; no significant changes in the morphology and packing density of the spiral ganglion neurons were observed. CONCLUSIONS AND SIGNIFICANCE: The effect of electrode array insertion on hearing and intracochlear fibrosis was significant. The process of fibrosis and endolymphatic hydrops seemed to not correlate with the degree of hearing loss, nor did it affect spiral ganglion neuron integrity in the 4-week postoperative period.

Spinal Cord Stimulator Paddle Lead Revision and Replacement for Misplaced or Displaced Electrodes.

OBJECTIVE: Spinal cord stimulators (SCSs) are commonly implanted via a laminotomy or laminectomy. Revision surgery may be necessary in instances of hardware failure or loss of efficacy. It is uncommon for leads to have been initially misplaced in a suboptimal position and revision in these cases necessitates additional dissection for appropriate repositioning. Accordingly, there is concern with a more extensive revision for a potentially higher risk of associated complications. This study aims to describe a series of patients with failed paddle SCS electrodes due to misplacement who underwent revision and replacement. METHODS: Patients who underwent SCS paddle replacement for misplaced paddles between 2021 and 2023 were identified. Medical charts were reviewed for demographic data, operative details, and incidence of complications. RESULTS: Sixteen patients underwent thoracic SCS paddle revision and replacement. The mean age was 59.6 ± 12.6 years, with 11 females and 5 males. Misplaced paddles were too lateral (n = 12), too high (n = 2), or incompletely within the epidural space (n = 2). The mean duration from initial implantation to revision surgery was 44.8 ± 47.5 months. The mean operative duration was 126.1 ± 26.9 minutes and all patients required a "skip" laminectomy or laminotomy. No complications were encountered. The mean length of follow-up was 18.4 ± 7.3 months. Mean preoperative pain intensity was 7.9 ± 1.5 and at last follow-up was 3.6 ± 1.7 (P < 0.001). All but 1 patient continued to use their device in follow-up. CONCLUSIONS: The revision and replacement of misplaced paddle SCS electrodes is a feasible and durable revision strategy, even in long-term implants with extensive scarring.

Designing next-generation subscalp devices for seizure monitoring: A systematic review and meta-analysis of established extracranial hardware.

Implantable brain recording and stimulation devices apply to a broad spectrum of conditions, such as epilepsy, movement disorders and depression. For long-term monitoring and neuromodulation in epilepsy patients, future extracranial subscalp implants may offer a promising, less-invasive alternative to intracranial neurotechnologies. To inform the design and assess the safety profile of such next-generation devices, we estimated extracranial complication rates of deep brain stimulation (DBS), cranial peripheral nerve stimulation (PNS), responsive neurostimulation (RNS) and existing subscalp EEG devices (sqEEG), as proxy for future implants. Pubmed was searched systematically for DBS, PNS, RNS and sqEEG studies from 2000 to February 2024 (48 publications, 7329 patients). We identified seven categories of extracranial adverse events: infection, non-infectious cutaneous complications, lead migration, lead fracture, hardware malfunction, pain and hemato-seroma. We used cohort sizes, demographics and industry funding as metrics to assess risks of bias. An inverse variance heterogeneity model was used for pooled and subgroup meta-analysis. The pooled incidence of extracranial complications reached 14.0%, with infections (4.6%, CI 95% [3.2 - 6.2]), surgical site pain (3.2%, [0.6 - 6.4]) and lead migration (2.6%, [1.0 - 4.4]) as leading causes. Subgroup analysis showed a particularly high incidence of persisting pain following PNS (12.0%, [6.8 - 17.9]) and sqEEG (23.9%, [12.7 - 37.2]) implantation. High rates of lead migration (12.4%, [6.4 - 19.3]) were also identified in the PNS subgroup. Complication analysis of DBS, PNS, RNS and sqEEG studies provides a significant opportunity to optimize the safety profile of future implantable subscalp devices for chronic EEG monitoring. Developing such promising technologies must address the risks of infection, surgical site pain, lead migration and skin erosion. A thin and robust design, coupled to a lead-anchoring system, shall enhance the durability and utility of next-generation subscalp implants for long-term EEG monitoring and neuromodulation.

Spinal Cord Stimulation Trial Electrodes Rapidly Produce Epidural Scarring, Impeding Surgical Paddle Lead Placement.

OBJECTIVES: After a successful percutaneous cylindrical electrode five-to-seven-day trial of spinal cord stimulation, subsequent permanent surgical paddle lead (SPL) placement can be impeded by epidural scar induced by the trial leads (TLs). Our goal was to determine whether a delay between TL and subsequent SPL placement provokes enhanced epidural scarring with an increased need for laminotomy extension required for scar removal for optimal SPL placement. MATERIALS AND METHODS: Using a prospectively maintained data base, a single-facility/surgeon retrospective study identified 261 patients with newly placed thoracolumbar SPLs from June 2013 to November 2023. Data were obtained from the patients' charts, including, but not limited to, timing between TL and SPL, operative time, and need for extension of laminotomy. RESULTS: We found that the need for laminotomy extension due to TL epidural scarring and longer operative times was not required in our patients if the SPL was placed within ten days of placement of the TL (0/26), leading to shorter operative times in those with SPL placed after ten days (122.42 ± 10.72 minutes vs 140.75 ± 4.72 minutes; p = 0.005). We found no association with other medical comorbidities that may be confounding factors leading to epidural scarring/extension of laminotomy or association with level of SPL placement, size of the spinal canal, or indication for SPL placement. CONCLUSIONS: TL placement leads to scarring in the epidural space that appears to mature after ten days of its placement. In approximately 34% of patients, this leads to prolonged operative time owing to the need for extension of laminotomy and subsequent clearing of epidural scar for optimal SPL placement.

Exploring Trauma Patterns and Contributing Factors With Slim Straight Electrode Array After Cochlear Implantation.

OBJECTIVE: To assess trauma patterns associated with the insertion of lateral wall electrode arrays. The study focused on 3 categories-scala tympani (ST), intermediate, and scala vestibuli (SV)-to identify traumatic patterns and contributing factors. STUDY DESIGN: Retrospective study. SETTING: Data from 106 cochlear implant recipients at a tertiary otologic center. METHODS: Demographic and surgical data were collected from recipients who underwent cochlear implantation manually and with RobOtol®. Measurements included cochlear dimensions, angular depth of insertion, and position of the first electrode. Three-dimensional reconstructions were used to analyze the electrode array location relative to the basilar membrane, categorized into ST, intermediate, and SV electrodes. Nontraumatic insertion was defined as all electrodes in the ST, while traumatic insertions had 1 or more electrodes in intermediate or SV locations. RESULTS: Out of 106 cases, 44% had nontraumatic and 56% had traumatic insertions. Demographic and surgical characteristics showed no association with traumatic insertions. A deeper position of the first electrode, relative to the round window, was associated with traumatic insertions (P = .03). Three trauma patterns were observed: distal (facing the apical electrodes), proximal (facing the middle electrodes around 180°), and distal/proximal. CONCLUSION: This study considers the intermediate position which could be associated with basilar membrane lesions. Risk zones for intracochlear trauma with lateral wall arrays were identified distally and proximally. Traumatic insertions were independently linked to deeper array placement. Future studies should explore whether gentler insertion, without insisting on further electrode array insertion depth, could reduce the trauma during cochlear implantation.

Evaluation of the in vivo chemical reactivity of a novel copolymer insulation on cardiac leads in a single-center study.

BACKGROUND: Human in vivo data on the chemical stability of different transvenous lead materials, particularly OptimTM leads, are lacking. OBJECTIVES: The purpose of this study was to determine the chemical reactivity of insulation materials by analyzing the molar mass of extracted pacing and defibrillator leads METHODS: We collected extracted leads at Emory University Hospitals and sent the leads with thermoplastic outer insulation material for molar mass analysis, a material characteristic that informs biostability. Leads were separated based on the chemical identity of the outer insulation material, and the molar mass was measured by an independent party. The extent of chemical reaction was compared across leads having different materials: poly(ether)urethane 55D, poly(ether)urethane 80A, and Optim. RESULTS: A total of 70 leads were extracted. The subset of extracted leads having outer insulation materials composed of PEU or Optim were analyzed for molar mass, where implant times ranged from 0.12 to 16.26 years. The rate of chemical degradation was compared by plotting the extent of reaction [Mn(t = 0)/Mn(t)] as a function of implant time. The Optim molar mass decreased to 40% of its initial value at 10 years of implant. No change in the molar mass of the PEU insulations could be resolved over the same 10-year implant time. CONCLUSION: Because the molar mass of a polymer is directly related to its mechanical integrity, the observed decrease in molar mass of Optim likely translates into premature insulation defects and is consistent with the observed increased rate of electrical malfunction/noise in this subset of cardiac leads.

Safety of Concomitant Cortical and Thalamic Stereoencephalography Explorations in Patients With Drug-Resistant Epilepsies.

BACKGROUND AND OBJECTIVES: Intracranial electrophysiology of thalamic nuclei has demonstrated involvement of thalamic areas in the propagation of seizures in focal drug-resistant epilepsy. Recent studies have argued that thalamus stereoencephalography (sEEG) may aid in understanding the epileptogenic zone and treatment options. However, the study of thalamic sEEG-associated hemorrhage incidence has not been investigated in a cohort study design. In this article, we present the largest retrospective cohort study of sEEG patients and compare hemorrhage rates between those with and without thalamic sEEG monitoring. METHODS: Retrospective chart review of clinical and epilepsy history, electrode implantation, rationale, and outcomes was performed for 76 patients (age 20-69 years) with drug-resistant epilepsy who underwent sEEG monitoring at our institution (2019-2022). A subset of 38% of patients (n = 30) underwent thalamic monitoring of the anterior thalamic nucleus (n = 14), pulvinar nucleus (n = 25), or both (n = 10). Planned perisylvian orthogonal sEEG trajectories were extended to 2- to 3-cm intraparenchymally access thalamic area(s).The decision to incorporate thalamic monitoring was made by the multidisciplinary epilepsy team. Statistical comparison of hemorrhage rate, type, and severity between patients with and without thalamic sEEG monitoring was made. RESULTS: Our approach for thalamic monitoring was not associated with local intraparenchymal hemorrhage of thalamic areas or found along extended cortical trajectories, and symptomatic hemorrhage rates were greater for patients with thalamic coverage (10% vs 0%, P = .056), although this was not found to be significant. Importantly, patients with perisylvian electrode trajectories, with or without thalamic coverage, did not experience a higher incidence of hemorrhage ( P = .34). CONCLUSION: sEEG of the thalamus is a safe and valuable tool that can be used to interrogate the efficacy of thalamic neuromodulation for drug-resistant epilepsy. While patients with thalamic sEEG did have higher incidence of hemorrhage at any monitoring site, this finding was apparently not related to the method of perisylvian implantation and did not involve any trajectories targeting the thalamus.

Migration and other electrode complications following cochlear implantation.

OBJECTIVES: To investigate migration and other electrode-related complications in cochlear implant surgery. METHODS: Retrospective review of all patients (adult and paediatric) undergoing cochlear implantation at a tertiary referral centre in England, between April 2019 and December 2021. Split arrays and patients who did not have post-op imaging were excluded. RESULTS: Two hundred and ninety-nine cochlear implants were performed including 90% primary and 10% revision surgeries. Two hundred and forty-eight (86%) of electrodes implanted were straight arrays.Twenty-seven (9%) demonstrated suboptimal position on post-operative imaging. Three (11%) were true migration, 4 (15%) possible migration, 15 (56%) had two or less extra-cochlear electrodes, 3 (11%) expected partial insertion and 2 (7%) demonstrated tip fold-overs. Twenty (74%) of arrays within the suboptimal insertion group were in primary surgeries. Six patients required re-implantation. The most common reason for re-implantation was migration. DISCUSSION: Electrode migration after cochlear implantation may be more common than previously thought. We demonstrate rates of migration congruous with current literature; this is despite robust and varied fixation techniques. Notable in our series is that all true captured migrations were seen exclusively in straight arrays. The majority of patients in the possible and confirmed migration group had normal inner ear anatomy. CONCLUSION: Suboptimal electrode position following cochlear implant surgery is a recognized complication and can affect implant performance. Reporting may increase with more widespread use of sophisticated post-operative imaging. Use of a pre-curved electrode and routine use of appropriate fixation techniques may reduce migration rates.

Pure endoscopic transcanal revision cochlear implantation for a misplaced electrode array: A novel and minimally invasive approach.

OBJECTIVES: Misplacement of the CI electrode array is one of the rarest complications of cochlear implant surgery. This condition can be noticed intraoperatively and diagnosed radiologically in the early postoperative period. To present a novel and minimally invasive revision approach for a misplaced cochlear implant (CI) electrode array. CASE: In this case report, the authors present a previously undescribed alternative minimally invasive revision cochlear implantation approach for a patient with a misplaced CI electrode array in the right ear who underwent bilateral simultaneous cochlear implantation one and a half years ago at another center. CONCLUSION: To correct CI electrode array misplacement, the endoscopic transcanal approach is a safe and effective alternative to the conventional approach.