Feasibility and Morbidity for the Use of MR-Guided Laser-Induced Thermotherapy for the Treatment of Skull Base Tumors: A Report of Three Cases.

Background Laser-induced thermotherapy (LITT) is a minimally invasive technique that has been demonstrated as an effective treatment of many pathologies; however, it has never been investigated for the use in skull base tumors. Case Series Three patients underwent LITT for treatment of skull base meningiomas. All three patients were determined to be poor candidates for open resection. Each patient was treated with a single laser fiber. Postoperative imaging confirmed ablation zones along the tract of the catheter in all three patients. Ablation zones were estimated to be 9 to 20% of the intended to treat tumor volume. Two of three treated patients suffered cranial nerve injury following the procedure with one patient diagnosed with neurotrophic keratitis and one patient with symptoms consistent with anesthesia dolorosa. Conclusion LITT is a technically feasible, minimally invasive treatment modality for skull base lesions. Significant risk to cranial nerves and small ablation zones afforded by a single cannula placement proposes serious obstacles. Further investigation is warranted prior to using this technique outside of a palliative indication.

Contralateral Transmaxillary Approach for Resection of Chondrosarcoma of the Petrous Apex: A Case Report.

BACKGROUND: Deep location and neurovascular structures make access to lesions of the petrous apex a significant challenge. A novel approach for these tumors is the contralateral transmaxillary approach. CLINICAL PRESENTATION: A 31-year-old male was evaluated for left abducens nerve palsy. Magnetic resonance imaging (MRI) and computed tomography revealed an enhancing, lytic lesion of the petrous apex with extension to the cavernous sinus and petroclival junction. The patient underwent a combined endoscopic contralateral transmaxillary and endoscopic endonasal transclival approach for resection of the lesion. No new or worsening neurologic deficits were noted following the procedure. Pathology revealed low-grade chondrosarcoma (grade I). Postoperative MRI revealed gross total resection of the lesion. Patient underwent adjuvant radiation therapy at the discretion of radiation oncology. CONCLUSION: The contralateral transmaxillary approach to the petrous apex allows for resection of lesions of the petrous apex with the ability to extend the dissection laterally. Excellent results achieved by institutions with advanced extended endoscopic endonasal experience can be reproduced in institutions with less experience. Further characterization of the risks and benefits of this approach is needed.

Infratemporal Fossa Vascular Anatomy Pertinent to Percutaneous Access to the Foramen Ovale for Treatment of Trigeminal Neuralgia: A Comparison of Cadaveric Dissection and Computed Tomography Analysis.

BACKGROUND: Trigeminal neuralgia may be treated via percutaneous access to the foramen ovale (FO). Vascular complications associated with the needle trajectory can result in serious morbidity and mortality. This study aimed to correlate the vascular relationships of the FO at the skull base via cadaveric dissections and computed tomography (CT). METHODS: Two fresh cadaver heads were injected with red and blue latex to delineate arteries and veins. Neck and infratemporal fossa dissections were carried out to delineate the vascular relationships of the FO. High-resolution head CT images of adult patients undergoing neurosurgical evaluations or procedures were analyzed for distances and sizes of skull base foramina in the infratemporal fossa. RESULTS: Three infratemporal fossa dissections (2 cadaveric specimens) were performed. Mean distance of FO to internal carotid artery was 2.4 ± 0.12 cm, and mean distance of FO to middle meningeal artery was 0.8 ± 0.16 cm. Head CT images of 52 patients (104 sides) with 1-mm axial slice thickness were analyzed. Area of the FO was 31.1 ± 9.6 mm2. Distance of FO to internal carotid artery was 1.70 ± 0.31 cm, and distance of FO to middle meningeal artery was 0.73 ± 0.61 cm. CONCLUSIONS: Cadaveric delineation of vascular structures in the infratemporal fossa correlates with head CT imaging and may be used to accurately plan percutaneous access to the FO. Inadvertent puncture of the extracranial internal carotid artery is nearly impossible with good technique. The most likely source of percutaneous vascular injury is the middle meningeal artery and distal branches of the maxillary artery.

An investigation into quality of life improvement in patients undergoing microvascular decompression for hemifacial spasm.

OBJECTIVE Hemifacial spasm (HFS) is a movement disorder characterized by involuntary spasms of the facial muscles, and it can negatively impact quality of life (QOL). This retrospective study and systematic review with meta-analysis was conducted to investigate the QOL in patients with HFS following intervention with microvascular decompression (MVD) and botulinum toxin (BT). METHODS In the retrospective analysis, a QOL questionnaire was administered to all patients undergoing MVD performed by a single surgeon. The QOL questionnaire included unique questions developed based on the authors' experience with HFS patients in addition to the health-related QOL HFS-8 questionnaire. The authors also report on a systematic review of the English literature providing outcomes and complications in patients with HFS undergoing treatment with either MVD or BT. RESULTS Regarding the retrospective analysis, 242 of 331 patients completed the questionnaire. The mean score of the 10 QOL questions improved from 22.78 (SD 9.83) to 2.17 (SD 5.75) following MVD (p < 0.001). There was significant improvement across all subscales of the questionnaire between pre- and postoperative responses (p < 0.001). Regarding the systematic review, it is reported that approximately 90% of patients undergoing MVD for HFS experience a complete recovery from symptoms, whereas the mean peak improvement of symptoms following treatment with BT is 77%. Furthermore, patients undergoing MVD reported a greater improvement in the mean supplemental index of QOL as compared with patients receiving BT therapy. CONCLUSIONS Microvascular decompression offers a significant improvement in QOL in well-selected patients suffering from HFS, and may offer an increased benefit for QOL over BT injections.

Utility of the intensive care unit in patients undergoing microvascular decompression: a multiinstitution comparative analysis.

OBJECTIVE Use of the ICU during admission to a hospital is associated with a significant portion of the total health care costs for that stay. Patients undergoing microvascular decompression (MVD) for cranial neuralgias are routinely admitted postoperatively to the ICU for monitoring. The primary purpose of this study was to compare complication rates of patients with and without a postoperative ICU stay following MVD. The secondary intents were to identify predictors of complications, to analyze variables of health care resource utilization, and to estimate the cost of postoperative management. METHODS The authors performed a retrospective comparative analysis of consecutive patients undergoing MVD at 2 institutions. A total of 199 patients without a postoperative ICU stay from Institution A and 119 patients with an ICU stay from Institution B were reviewed. Inclusion criteria included any adult (i.e., 18 years of age or older) undergoing MVD for trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia, or geniculate neuralgia. Patients with incomplete medical records were excluded. Medical comorbidities, intraoperative variables, complications, postoperative interventions, and variables indicating health care resource utilization were reviewed. RESULTS The study compared 190 patients without a postoperative ICU stay from Institution A with 90 patients with an ICU stay from Institution B. Seven patients without an ICU stay and 5 patients with an ICU stay experienced complications after surgery (p = 0.53). Multivariate analysis identified coronary artery disease to be a predictor of complications (p = 0.037, OR 6.23, 95% CI 1.12-34.63). Patients from Institution A without a postoperative ICU stay had a significantly shorter length of stay, by approximately 16 hours (p < 0.001), and received less postoperative imaging (p < 0.001, OR 14.39, 95% CI 7.75-26.74) and postoperative diagnostic testing (p < 0.001) than patients from Institution B with an ICU stay. Estimated cost savings in patients without an ICU stay and 1 less day of inpatient recovery was calculated as $1400 per patient. CONCLUSIONS Selective versus routine use of ICU care as well as postoperative imaging and diagnostic testing may be safe after MVD and can lead to a reduction in overall health care costs.

Retinal Structures and Visual Cortex Activity are Impaired Prior to Clinical Vision Loss in Glaucoma.

Glaucoma is the second leading cause of blindness worldwide and its pathogenesis remains unclear. In this study, we measured the structure, metabolism and function of the visual system by optical coherence tomography and multi-modal magnetic resonance imaging in healthy subjects and glaucoma patients with different degrees of vision loss. We found that inner retinal layer thinning, optic nerve cupping and reduced visual cortex activity occurred before patients showed visual field impairment. The primary visual cortex also exhibited more severe functional deficits than higher-order visual brain areas in glaucoma. Within the visual cortex, choline metabolism was perturbed along with increasing disease severity in the eye, optic radiation and visual field. In summary, this study showed evidence that glaucoma deterioration is already present in the eye and the brain before substantial vision loss can be detected clinically using current testing methods. In addition, cortical cholinergic abnormalities are involved during trans-neuronal degeneration and can be detected non-invasively in glaucoma. The current results can be of impact for identifying early glaucoma mechanisms, detecting and monitoring pathophysiological events and eye-brain-behavior relationships, and guiding vision preservation strategies in the visual system, which may help reduce the burden of this irreversible but preventable neurodegenerative disease.