How We Do It: Using a surgical navigation system in the management of the ossified cochlea

Abstract

The ossified cochlea poses both concerns and challenges to any implant team. One of the surgical aims is to implant as many of an implant system's electrodes into the cochlea as close to the modiolus as possible, thus facilitating stimulation of the surviving cell bodies in the spiral ganglion. Within the field of otorhinolaryngology various surgical navigation systems have been introduced to facilitate surgical orientation during endoscopic sinus and skull-base surgery. The principle behind such systems is that specialized software uses high-resolution computerized tomography and magnetic resonance imaging scans to create a 3D image of the patient's anatomy. This 'virtual patient model' is then 'registered' with the patient's anatomical landmarks. Surgical instruments registered into, or linked with, the system can then be tracked within the 3D model. This is the first time this system has been described for surgery of the inner ear, and we describe how the technique allows more precise control of the bur tip while drilling tunnels that approximate with the apical and distal parts of the basal coil of the ossified cochlea.

Implantation of the Completely Ossified Cochlea

“…8 Similar to the presented case, they performed a two-tunnel cochlear drill-out procedure and implanted a split array. Using the Medtronic Xomed LandmarX system (Medtronic-Xomed, Jacksonville, FL), a surgical drill was fitted with a small infrared emitting diode and registered to a reference head frame.…”

“…Such constrained linear drilling may be particularly useful in navigating the ossified cochlea given restricted access through the facial recess corridor, close proximity to vital structures including the facial nerve, modiolus, and internal carotid artery and obscured surgical landmarks from neossofication. 8 We report use of such a system for cochlear drill-out in a patient with complete cochlear ossification. Proximal and distal basal turn access permitted full split array electrode insertion after an unsuccessful attempt was made on the contralateral side using conventional technique.…”

Evaluation of intraoperative cone beam computed tomography and optical drill tracking in temporal bone surgery

“…As described above, the imaging protocol specifies CBCT image acquisition with a radiation dose of 0.35 mSv per scan, with up to four to six intraoperative image updates over the course of a procedure such that the accumulated dose is less than a typical diagnostic CT scan (2)(3)(4)(5). 16 Due to the half-circular (approximately 178 ) orbit of the C-arm gantry, in which the xray tube travels below the table and only posterior to the head, the dose to radiosensitive structures (e.g., the eyes) may be considerably lower for cone beam imaging than for conventional diagnostic CT using a full 360 orbit.…”

Submillimetric target-registration error using a novel, non-invasive fiducial system for image-guided otologic surgery

“…Raine et al [17] reported the use of an IGS system for a customized cochlear implant placement in a patient with an abnormally ossified inner ear. Caversaccio et al [18] recently reported on the use of IGS systems in repairing aural atresia, a condition in which the ear canal does not properly develop.…”