Atlantoaxial Stabilization Using C1 Lateral Mass and C2 Pedicle/Translaminar Screw Fixation by Intraoperative C1- and C2-Direct-Captured Navigation with Preoperative Computed Tomography Images

In C1–C2 posterior fixation, the C1 lateral mass and C2 pedicle/translaminar screw insertion under spine navigation have been used frequently. To avoid the risk of neurovascular damage in atlantoaxial stabilization, we assessed the safety and effectiveness of a preoperative computed tomography (CT) image-based navigation system with intraoperative independent C1 and C2 vertebral registration. It is ideal when a reference frame can be linked directly to the C1 posterior arch for C1-direct-captured navigation, but there is a mechanical challenge. A new spine clamp-tracker system was implemented recently, which allows reliable C1- and C2- direct-captured navigation in nine patients with traumatic C2 fractures. In this way, there was no misalignment of C1–C2 screws. C1 lateral mass screws were used except for one case, and translaminar screws were primarily used as an anchor for C2. The C1 lateral mass screw locations, which are 19 mm laterally from the C1 posterior arch’s center, are taken to be constant. However, there is one unusual circumstance in which using a C1 laminar hook instead of a C1 lateral mass screw appears to be a beneficial substitute. The increase of surgical accuracy for posterior C1–C2 screw fixation without cost constraints is significantly facilitated by intraoperative C1- and C2-direct-captured navigation with preoperative computed CT images.

A Case of a Meningeal Carcinomatosis of the Internal Auditory Meatus Treated as Sudden Deafness / 대한평형의학회지

We describe a case of meningeal carcinomatosis of the internal auditory meatus presenting as sudden deafness accompanied by dizziness. A 54-year-old woman complained of acute right-side hearing loss in October 2014. The pure tone audiometry test revealed right-side hearing loss of 47.5 dB. She was treated with oral steroids. Her hearing as well as her symptoms of dizziness worsened and she was admitted for further examination. Her right and left-side hearing had worsened to 105.0 dB and 47.5 dB, respectively. A magnetic resonance imaging scan of the head revealed bilateral enhancement of the internal auditory canal and multiple brain metastases. The chest radiograph revealed a mass in the left lung. Adenocarcinoma of the lung was diagnosed. Lumbar puncture yielded no evidence of carcinoma cells in the cerebrospinal fluid, but an increased number of lymphocytes was confirmed. A diagnosis of multiple brain metastases and leptomeningeal metastasis from the adenocarcinoma of the lung was considered. Whole-brain radiation therapy (30 Gr/10 fractions) was administered. Progressive bilateral hearing loss is a rare first manifestation of meningeal carcinomatosis. It is quite important to consider the possibility of this condition when patients present with sudden deafness.