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. The patientIn 1997, Mr O, at the age of 50 years, developed pneumococcal meningitis. As a result he suffered a profound hearing loss but, apart from initial vertiginous problems, no other sequelae. He was promptly referred and assessed but did not want an implant. Two years later he returned having changed his mind. Computerized tomography (CT) imaging at this stage showed total ossification

Image‐guided surgical navigation in otology

“…Using intraoperative anatomic landmarks in combination with fiducials, they found the accuracy within the temporal bone region to be between 0.9 to 1.5 mm and found the system decreased operating time and increased safety in a series of 11 patients. The LandmarX system has also been reported to be very effective in one case of split cochlear implant electrode placement 19. Various studies in cadavers of similar infrared emitting diode, optical tracking systems have found excellent accuracies (<1 mm), although these measures do not account for registration errors, preoperative imaging error, or fiducial placement errors 20–22.…”

Use of bone anchoring device in electromagnetic computer-assisted navigation in lateral skull base surgery

“…CAN with the Digipointeur has already been tested in an experimental study simulating cochlear implant surgery with a keyhole approach in five temporal bones [14]. Other studies employed CAN in the case of ossified cochlea during a cochlear implantation [15] or in aural atresia [16]. The procedure should be reproducible and reliable, in order to have confidence with this system.…”

Stereotactic navigation for TAMIS-TME

“…Because navigation only requires a fixed anatomic target, its application outside the realm of neurological surgery has been proven (especially) for orthopedic surgery (8)(9)(10)(11)(12), but also for otic surgery (13,14), adrenal surgery (15), and liver targeted procedures from concept (16)(17)(18) to reality (19). For oncologic surgery of the rectum, and with the recent evolution of transanal total mesorectal excision (taTME) (20)(21)(22), navigation has been successfully applied to help guide surgeons in real-time with this new and advanced procedure that mandates considerable skill (23,24).…”