Pain After Cochlear Implantation: An Unusual Complication?

OBJECTIVE

To analyze clinical signs and better define the underestimated long-term pain after implantation, to discuss etiological hypothesis, and to propose our department treatment algorithm and results.

STUDY DESIGN AND SETTING

Retrospective review of children implanted with complaints of atypical pain in the area of device implantation, not in the immediate postoperative period, more than or equal to 4 on the Visual Analog Pain Scale (VAPS: 0-10) in the ENT pediatric department of Trousseau and Necker Enfants Malades Hospitals between 1998 and 2015.

PATIENTS

All patients had full clinical and electrophysiological checking, and had normal functioning device. Exclusion criteria were: related history of local trauma, ongoing skin infection, magnet displacement, and device failure.

INTERVENTION(S): Treatments and outcomes were reviewed, with a minimum of 6 months follow up. Two groups were analyzed: Group PS: pain associated with local swelling (n = 9) and Group P: isolated pain (n = 11). The first-line treatment was medical. In Group PS, anti-inflammatory, pain medication, and antibiotics were used at the same time; in Group P, only anti-inflammatory and pain medication was used.

MAIN OUTCOME MEASURE(S): Success was defined when complete resolution of pain and swelling (pain scale = 0).

RESULTS

Twenty cases out of the 1,448 implanted patients in our department (1.4%) were included. Average age at first occurrence of pain was 15 years (3-22 yr). Mean delay between surgery and pain complaint was 5.8 years (0.25-14). Mean follow up was 2 years (0.5-5 yr).First line medical treatment was successful in eight cases (40%). Of the 12 patients who failed medical treatment and required surgery, two had resolution of pain with magnet change and 10 had resolution with reimplantation. (5/9 patients in Group PS and 7/11 in Group P).Microbiology was performed in 10/20 cases and analysis of explanted devices was performed in 7/10 cases. Positive microbiological culture of soft tissues was positive for 3/10 cases, biofilm was positive for 5/7 cases.Pain in the area of the implanted device can occur shortly after surgery or on long-term follow up. It has been seen in all device types. Pain may be clinically underestimated, as low VAPS grade (<5) or intermittent pain may be not reported. Low-grade infections might be a hypothesis to explain these pain. Management may include medical or surgical intervention.

CONCLUSION

Pain in the implanted area can be a major complication leading to implant non-use. Rate may be underestimated because of the lack of medical report. At explantation, we recommend systematic evaluation of biofilm and device failure regardless of the suspected etiology of the pain.