Minimally Invasive Tubular Approach for Occipital Condylar Biopsy and Resection: Case Report and Review of Literature.

BACKGROUND: Patients with isolated occipital condyle lesions concerning for metastases rarely undergo surgical biopsies and are more commonly treated with empirical radiation with or without chemotherapy. This is likely related to the morbidity associated with open condylar approaches and the importance of surrounding structures. We present a minimally invasive technique to approach the occipital condyle using a tubular dilating retractor system. CASE DESCRIPTION: A 38-year-old woman with medical history of breast cancer presented with a 2-month history of headache localizing to the right occipital area and right tongue deviation. Magnetic resonance imaging revealed a heterogeneously enhancing mass within the right occipital condyle. The patient was brought into the operating room and placed in prone position. A 2-cm paramedian incision was made on the right approximately 2.5 cm off midline at the level of C1. Sequential dilation using a tubular retractor system was performed under fluoroscopic guidance. Once the condylar cortex was identified and entered, the tumor was immediately visualized and resected. Operative time was 65 minutes and estimated blood loss was 5 mL. The patient was discharged to home on postoperative day 1. CONCLUSIONS: This report, to our knowledge, presents the first case of a minimally invasive tubular retractor system-based approach for biopsy and resection of an occipital condylar metastasis causing occipital condyle syndrome. This approach allows for tissue diagnosis to precisely dictate medical management and minimizes the morbidity associated with traditional open surgical approaches.

Solitary Infiltrating Meningioma of the Trochlear Nerve: Case Report.

We report the case of a solitary meningioma infiltrating the trochlear nerve, the first in a patient without a neurocutaneous disorder or cavernous sinus involvement. The patient presented with diplopia was found to have a focal enhancing mass encompassing the trochlear nerve. Following surgical resection, pathological examination showed meningioma infiltrating the nerve itself, demonstrated on the included pathology images. A review of the literature and discussion of meningiomas infiltrating cranial nerves are included.

Combined Open and Endoscopic Endonasal Skull Base Resection of a Rare Endometrial Carcinoma Metastasis.

In the absence of significant extracranial disease, patients with solitary brain metastases have shown benefit with resection. Brain lesions due to endometrial cancer are uncommon, and the only described skull base involvement is limited to the pituitary gland. We report the case of a 60-year-old female with endometrial cancer who presented with weeks of right cheek pain and numbness that was accompanied by headaches. We describe the magnetic resonance imaging (MRI) findings and surgical resection of a solitary endometrial metastasis involving the infratemporal fossa, middle fossa, cavernous sinus, trigeminal nerve, and nasal sinuses. Due to extensive nasal and lateral involvement, a combined open and endoscopic approach was planned. The patient was discharged home without complication. She underwent adjuvant radiotherapy. Despite its suspected indolent course, intracranial endometrial adenocarcinoma metastases are gaining higher prevalence. This case report documents the first direct neural spread of an endometrial primary, and highlights the potential for extra-axial sites of metastasis.

Magnetic resonance imaging in the prone position and the diagnosis of tethered spinal cord.

OBJECTIVE Tethered cord syndrome (TCS) is a neurosurgical disorder with varied clinical manifestations believed to result from vascular compromise due to stretch forces on the spinal cord. Conventional supine MRI findings may include a low-lying conus medullaris, thickened or fat-infiltrated filum terminale, or lipoma; however, imaging sensitivity and specificity for tethered cord can be low. The purpose of this study was to evaluate the utility of prone MRI in the diagnosis of tethered and retethered spinal cord. METHODS Medical records were reviewed in 41 patients who underwent surgical release of tethered cord and in whom preoperative prone MRI sequences were available. Patients were divided into Group 1 (new TCS diagnosis) and Group 2 (recurrent TCS after previous untethering). Absolute conus ventral motion and motion as a percentage of canal width between supine and prone positions was measured in these 2 groups via sagittal T2-weighted sequences; these groups were compared with 30 consecutive patients (Group 3) who were classified as the normal control group. RESULTS The mean ventral motion was as follows: Group 1 (absolute: 0.5 ± 0.5 mm [range 0-2.4 mm]; canal percentage: 3.7% ± 3.9% [range 0%-16.3%]); Group 2 (absolute: 0.4 ± 0.7 mm [range 0-2.6 mm]; canal percentage: 2.2% ± 3.7% [range 0%-14.0%]); and Group 3 (absolute: 3.4 ± 1.3 mm [range 1.4-5.6 mm]; canal percentage: 22.0% ± 7.2% [range 10.5%-36.1%]). Whereas 38/41 surgically treated patients with TCS had diminished (< 10% canal width) ventral motion on preoperative MRI, 30/30 controls had > 10% canal width motion. Sensitivity and specificity were thereby calculated as 92.7% and 100%, respectively. CONCLUSIONS In the present series, prone imaging is found to be a sensitive and specific tool, and the authors believe it may have a role as supportive evidence in the diagnosis of tethered and retethered spinal cord.

Supraorbital Keyhole Craniotomy for Basilar Artery Aneurysms: Accounting for the "Cliff" Effect.

BACKGROUND: Treatment of basilar artery aneurysms is challenging. While endovascular techniques have dominated, there still remain circumstances where open surgical clipping is required or preferred. Minimally invasive "keyhole" approaches are being used more frequently to provide the durability of surgical clipping with a lower morbidity profile; however, careful patient selection is required. The supraorbital "keyhole" approach has been described for the treatment of basilar artery aneurysms, but careful assessment of the basilar exposure is necessary to ensure proper visualization of the aneurysm and ability to obtain proximal vascular control. Various methods of estimating the basilar artery exposure in this approach have been described, including the anterior skull base line and the posterior clinoid line, but both are unreliable and inaccurate. OBJECTIVE: To propose a new method, the orbital roof-dorsum line, to simply and accurately predict the basilar artery exposure. METHODS: CT angiograms for 20 consecutive unique patients were analyzed to obtain the anterior skull base line, posterior clinoid line, and the orbital roof-dorsum line. CT angiograms were then loaded onto a Stealth neuronavigation system (Medtronic, Minneapolis, Minnesota) to obtain "true" visualization lengths. A case illustration is presented. RESULTS: Pairwise comparison tests demonstrated that both the anterior skull base and the posterior clinoid estimation lines differed significantly from the "true" value ( P < .0001). Our orbital roof-dorsum estimation provided results that accurately predicted the "true" value ( P = .71). CONCLUSION: The orbital roof-dorsum line provides a simple and reliable method of estimating basilar artery exposure and should be used whenever considering patients for surgical clipping by this approach.

Radiographic Assessment of the presigmoid retrolabyrinthine approach.

BACKGROUND: Lesions of the petroclival fissure are difficult to access surgically. Both retrosigmoid and presigmoid retrolabyrinthine approaches have been described to successfully treat these complex tumors. The retrosigmoid approach offers quick and familiar access, whereas the presigmoid retrolabyrinthine approach reduces the operative distance and the need for cerebellar retraction. The presigmoid retrolabyrinthine approach, however, is constrained by anatomical limits that can be subject to patient variation. We sought to characterize the surgically relevant variation to guide preoperative assessment. METHODS: One hundred and seventy-seven high-resolution computed tomography scans of the head (without preexisting pathology) were reviewed. Three hundred and fifty-four temporal bone scans were analyzed for level of aeration, size of Trautmann's triangle dura, and petrous slope. Petrous slope is the angle between the anterior sigmoid sinus and the petroclival fissure at the level of the internal acoustic canal. RESULTS: Trautmann's triangle area had a mean of 185.15 mm2 (range 71.4-426.7 mm2). Petrous slope had a mean value of 149° (range 106-178°). Increasing aeration was found to be correlated with decreasing petrous slope and decreasing Trautmann's triangle area. CONCLUSION: The presigmoid retrolabyrinthine approach is uniquely confined. Variations in temporal bone anatomy can have dramatic impacts on the operative time, risk profile, and final exposure. Preoperative assessment is critical in guiding the surgeon on the appropriateness of approach. Preoperative measurement of Trautmann's triangle, petrous slope, and aeration can help to reduce surgical morbidity.

Clinical Outcomes of Cervical Laminoplasty: Results at Two Years.

BACKGROUND: Laminoplasty is an established treatment for cervical myelopathy. Multiple variations have emerged, many advocating the use of allograft, but controversy persists. OBJECTIVE: To assess medium-term clinical outcomes in patients who underwent laminoplasty with autograft at our institution. METHODS: Thirty-two consecutive patients (19 male, 13 female, average age 66 yr) from our prospective outcome registry that underwent cervical laminoplasty between 2009 and 2013 were reviewed. Computed tomography (CT) scan was performed immediately postoperatively and at 6-mo follow-up. Parameters included patient perception of outcome, Nurick score, Neck Disability Index (NDI), visual analog scale for neck pain, and SF-36. RESULTS: On retrospective analysis, all patients felt improved at 3 mo postoperatively; at 2 yr, this rate was 91%. Improvements were seen in Nurick scores, from 3.16 ± 0.9 preoperatively to 1.94 ± 0.8 at 2 yr; NDI score from 28.7% ± 9% preoperatively to 20.8% ± 9.6% at 2 yr; visual analog scale from 2.8 ± 1.2 preoperatively to 1.7 ± 0.9 at 2 yr; and SF-36 physical component summary from 27.9 ± 10 preoperatively to 37.8 ± 11.9 at 2 yr. All values reached significance at all follow-up points ( P < .05) with the exception of 6-mo NDI values ( P = .062). No C5 palsy, graft complications, or reclosure was observed in any patient during the follow-up period. CONCLUSION: Laminoplasty with autograft is a safe and effective method to treat cervical myelopathy, with good medium-term clinical outcome. No reclosures were observed. Bony fusion was seen in all cases on CT scan. Our study found good outcomes in the performance of open-door laminoplasty without hardware, in the treatment of cervical stenosis.