Clinical Scorecard: Pediatric Auditory Brainstem Implantation: Our Surgical Approach

At a Glance

Key Highlights

• ABI systems consist of internal receiver-stimulator implanted in temporal bone and external microphone and processor.
• Retrosigmoid craniotomy approach preferred in pediatric non-NF2 patients to preserve inner ear and reduce operative time.
• Intraoperative landmarks include foramen of Luschka, 9th cranial nerve, and veins to locate cochlear nucleus for electrode placement.

Guideline-Based Recommendations

Diagnosis

• Use radiological, audiometric, and electrophysiological assessments to select implant side.
• Select side with most accessible lateral recess if no functional hearing in either ear.
• Prefer side with better auditory cortex development if one ear has residual hearing but is not CI candidate.

Management

• Position patient supine with head turned contralaterally and use Mayfield skull clamp.
• Employ facial nerve monitoring and implant evoked auditory brainstem response (EABR) intraoperatively.
• Perform retrosigmoid craniotomy with postauricular incision and create subperiosteal pocket for device.
• Locate lateral recess using 9th cranial nerve and choroid plexus landmarks and secure electrode paddle adjacent to cochlear nucleus.
• Drill bony well in squamous temporal bone for receiver-stimulator and secure device with tie-down sutures.

Monitoring & Follow-up

• Use facial nerve monitoring with electrodes in orbicularis oculi and orbicularis oris muscles.
• Apply intraoperative implant evoked auditory brainstem response (EABR) with recording electrodes at midline, vertex, inion, C7 vertebrae, and contralateral mastoid.

Risks

• Potential injury to cranial nerves during retrosigmoid approach.
• Risk of inadequate electrode placement leading to suboptimal auditory stimulation.
• Operative risks related to craniotomy and brainstem manipulation.

Patient & Prescribing Data

Pediatric patients with auditory nerve aplasia or NF2-related hearing loss unsuitable for cochlear implants

ABI implantation via retrosigmoid approach is feasible and preserves inner ear structures, optimizing auditory outcomes.

Clinical Best Practices

• Select implant side based on comprehensive audiological and imaging evaluation.
• Use retrosigmoid craniotomy to minimize operative time and preserve vestibular function in children.
• Employ intraoperative neuromonitoring including facial nerve and EABR to optimize electrode placement and minimize complications.
• Create a secure bony well and subperiosteal pocket for stable device implantation.
• Identify anatomical landmarks carefully to ensure accurate electrode positioning adjacent to cochlear nucleus.

References

• Colletti et al. First pediatric ABI surgery for auditory nerve aplasia, 2001
• House Ear Institute development of ABI, late 1970s
• Anatomy and surgical landmarks of cochlear nucleus and lateral recess
• Retrosigmoid approach advantages in pediatric ABI surgery