Pain After Cochlear Implantation Without Signs of Inflammation: A Systematic Review

Neuromodulation Systems in the Setting of Cochlear Implant Treatment Based on Case Reports and Literature Review

OBJECTIVES

Cochlear implants are an established and proved method for auditory rehabilitation. In addition, neuromodulation systems for treating severe movement and pain disorders are gaining importance. To date, there is limited information regarding the concurrent use of the various implanted systems and potential electromagnetic interferences. In this case series, we assess the simultaneous use of cochlear implants and neuromodulation systems such as deep brain stimulation (DBS), occipital nerve stimulation (ONS) and peripheral nerve field stimulation (PNFS) on the basis of three retrospectively investigated case reports from our clinic.

MATERIALS AND METHODS

Case 1 is a patient aged 30 years with preexisting DBS system (Medtronic Activa RC, Medtronic, Dublin, Ireland) for idiopathic dystonia, who underwent cochlear implantation for severe-to-profound hearing loss. Cases 2 and 3 are patients aged 72 and 57 years, respectively, with cochlear implants in whom a neuropathic pain syndrome developed postoperatively. After unsuccessful medical and physiotherapeutic therapy, implantation of an ONS stimulator (Nuvectra-Algovita system, Plano, TX) and a permanent PNFS system with two periauricular electrodes (Boston Scientific WaveWriter R16, Marlborough, MA) was performed.

RESULTS

In all three cases, the fitting parameters of the cochlear implant and the postoperative hearing impression were not affected. In the first case, the patient achieved speech understanding of 65% at 65 decibels sound pressure level (dB SPL) in the Freiburg monosyllabic test three months after surgery. In the second and the third case, speech comprehension remained good after ONS and PNFS intervention. DBS stimulation could be continued without complications and the occurrence of neurologic symptoms. Furthermore, a good and long-term reduction in pain intensity was achieved by implanting the ONS stimulator and the PNFS system.

CONCLUSION

This case series shows that the simultaneous use of cochlear implants and other neuromodulation systems seems possible without complications and disruptive interactions.

Pain at the Cochlear Implant Site Requiring Device Removal in Pediatric Patients

OBJECTIVES

Idiopathic pain at the cochlear implant (CI) site outside of the immediate postoperative period is an uncommon occurrence but may necessitate device explantation. Our objective was to describe the clinical course for pediatric patients with CI site pain who ultimately required device explantation.

STUDY DESIGN

Retrospective chart review.

METHODS

We performed a retrospective database review of CIs performed at a tertiary referral center for pediatric cochlear implantation. We specifically evaluated pediatric patients who presented with pain at or near the CI device site and ultimately required explantation.

RESULTS

Fifteen patients (16 CIs) had pain at or near the CI site requiring device explantation. Cultures taken during site exploration or device explantation identified bacteria in 86% and 81% of procedures, respectively. Propionibacterium acnes and Staphylococcus non-aureus were the most commonly identified organisms.

CONCLUSIONS

The majority of patients with idiopathic pain in this cohort ultimately requiring CI explantation had chronic bacterial colonization.

LEVEL OF EVIDENCE

Level 4 (Case series) Laryngoscope, 2022.

Multimodal Analysis of the Tissue Response to a Bone-Anchored Hearing Implant: Presentation of a Two-Year Case Report of a Patient With Recurrent Pain, Inflammation, and Infection, Including a Systematic Literature Review

Osseointegration is a well-established concept used in applications including the percutaneous Bone-Anchored Hearing System (BAHS) and auricular rehabilitation. To date, few retrieved implants have been described. A systematic review including cases where percutaneous bone-anchored implants inserted in the temporal bone were retrieved and analyzed was performed. We also present the case of a patient who received a BAHS for mixed hearing loss. After the initial surgery, several episodes of soft tissue inflammation accompanied by pain were observed, leading to elective abutment removal 14 months post-surgery. Two years post-implantation, the implant was removed due to pain and subjected to a multiscale and multimodal analysis: microbial DNA using molecular fingerprinting, gene expression using quantitative real-time polymerase chain reaction (qPCR), X-ray microcomputed tomography (micro-CT), histology, histomorphometry, backscattered scanning electron microscopy (BSE-SEM), Raman spectroscopy, and fluorescence in situ hybridization (FISH). Evidence of osseointegration was provided via micro-CT, histology, BSE-SEM, and Raman spectroscopy. Polymicrobial colonization in the periabutment area and on the implant, including that with Staphylococcus aureus and Staphylococcus epidermidis, was determined using a molecular analysis via a 16S-23S rDNA interspace [IS]-region-based profiling method (IS-Pro). The histology suggested bacterial colonization in the skin and in the peri-implant bone. FISH confirmed the localization of S. aureus and coagulase-negative staphylococci in the skin. Ten articles (54 implants, 47 patients) met the inclusion criteria for the literature search. The analyzed samples were either BAHS (35 implants) or bone-anchored aural epitheses (19 implants) in situ between 2 weeks and 8 years. The main reasons for elective removal were nonuse/changes in treatment, pain, or skin reactions. Most samples were evaluated using histology, demonstrating osseointegration, but with the absence of bone under the implants’ proximal flange. Taken together, the literature and this case report show clear evidence of osseointegration, despite prominent complications. Nevertheless, despite implant osseointegration, chronic pain related to the BAHS may be associated with a chronic bacterial infection and raised inflammatory response in the absence of macroscopic signs of infection. It is suggested that a multimodal analysis of peri-implant health provides possibilities for device improvements and to guide diagnostic and therapeutic strategies to alleviate the impact of complications.