13Going Back In: Revision and Reimplantation

CWhy an implant comes out: hard failure, soft failure and medical cause

Indications cluster into three groups: confirmed device failure, medical/surgical complications, and a wish to upgrade. A hard failure is an objectively proven device fault — open or short circuits, loss of telemetry, no integrity test response. The diagnosis is unambiguous and reimplantation is clearly indicated. A soft failure is a decline in performance or distressing symptoms (pain, shocks, aberrant non-auditory stimulation) without a reproducible in-vivo fault; the Balkany consensus framework was created to standardise how these are worked up before explant. Medical indications include device extrusion, flap breakdown, deep wound infection unresponsive to antibiotics, electrode misplacement (tip fold-over, scala vestibuli or extracochlear placement), and migration. Trauma over the receiver-stimulator and recalcitrant infection can force urgent explant; a soft failure should never be reimplanted until reversible causes (a programming or processor fault) are excluded.[2005][2013][2004]

TThe operation: re-using the path you already made

Revision surgery generally re-uses the original incision, well and cochleostomy/round-window track rather than starting afresh. Around the original array a fibrous sheath forms in the scala tympani; preserving this tract lets the surgeon withdraw the old array and pass the new one along the same channel. Full reinsertion to the original depth is achievable in the large majority of cases when the cochlea is patent and the sheath intact; new ossification or fibrosis is the main obstacle to a complete reinsertion. Perimodiolar (precurved) arrays demand care on withdrawal — uncoiling force can disrupt the sheath or injure the modiolus, a particular concern for children facing possible future reimplantations. Intraoperative integrity testing and impedance/telemetry on the new device confirm function before closure; imaging may confirm position.[2007][2004]

COutcomes: reassuringly good

Across adult and paediatric series, reimplantation restores or maintains speech-perception performance in the large majority of patients — most return to or exceed their pre-explant level. Paediatric series report low surgical complication rates and excellent audiological recovery after reimplantation; auditory performance returns to pre-explant levels within about six months in most children. The exception to watch is the patient reimplanted for soft failure with poor immediate auditory function: a subset recovers less predictably, underscoring careful candidacy before explant. Switching manufacturer at reimplantation does not in itself harm outcome — performance stays stable or improves whether the new device is the same or a different make. Reimplantation rates fall over roughly 1–8% depending on era and population, higher in children; device (hard/soft) failure is consistently the leading single cause, followed by medical complications.[2013][2007][2018]

CCounselling: a known road, not a fresh start

Families should hear at consent that reimplantation is one of the more predictable revision otologic operations, with the original surgical path largely re-usable. Set the expectation honestly: most patients regain their previous hearing, but a short re-mapping and rehabilitation period follows, and recovery is not always instantaneous. Soft-failure candidates need extra counselling because the benefit is less certain than for a clear-cut hard failure. Document that reimplantation does not generally preclude future upgrades, and that preserving the cochlea now protects later options. Reassure that the lifetime risk of needing a reimplant is low and that modern device reliability continues to improve.[2005][2018]