Transorbital

Abstract: Background Transorbital neuroendoscopic surgery (TONES) pathways attempt to address some of the technical challenges of accessing laterally placed anterior skull base lesions or paramedian lesions that cross neurovascular structures. TONES approaches allow simultaneous coplanar visualization and working space above and below the skull base. Objective To present an anatomic study, a description of the surgical techniques, and an analysis of the safety and efficacy of 20 consecutive procedures using TONES for a variety of pathological conditions. Methods Sixteen patients underwent 20 TONES procedures for anterior skull base pathology, including repair of cerebrospinal leak, optic nerve decompression, repair of cranial base fractures, and removal of 3 skull base tumors. Ten patients were male, and 6 were female. The mean age at presentation was 44 years. Follow-up was 6 to 18 months with a mean of 9 months. Results There were no significant complications or treatment failures in any of the 20 procedures. A variety of pathological conditions were treated, including cerebrospinal fluid leaks, fractures, mass lesions, and tumors. The TONES approach provided up to 4 separate access ports with ample exposure for manipulation and correction of the pathology. Conclusion This anatomic and prospective outcome study demonstrates that TONES provides safe and effective coplanar endoscopic access to the anterior and middle cranial base. These novel TONES approaches may be added to the wide range of published minimally invasive armamentarium when approaching challenging skull base pathology.

Abstract: BACKGROUND The use of an ultrasound-based evaluation of the optic nerve sheath diameter (ONSD) has previously been demonstrated for detecting raised intracranial pressure. In order to be feasible in clinical workup, the test qualities of transorbital ultrasonography need to be determined. The aim of this study was therefore to establish normal values and to assess the intra- and interobserver reliability of this method. METHODS Using a 9-3 MHz linear array transducer, the ONSD of 40 healthy subjects was independently measured by 2 investigators. RESULTS Depicting the optic nerve and its sheath was possible in all individuals. The mean ONSD was 5.4 ± .6 mm with a range of 4.3-7.6 mm. The intraobserver reliability analyzed with Cronbach's Alpha was found to be high with values between .92 and .97. Pearson's correlation coefficient between the 2 investigators was .81 on the right side and .84 on the left. There was no correlation between ONSD and age, body mass index, or gender. CONCLUSIONS Transorbital B-mode sonography is a feasible method to assess the ONSD with a high intra- and interobsever reliability. Normal values on ONSD are presented in this study that will be useful in future studies on pathological conditions.

Abstract: Temporary (15 minutes to 24 hours) or permanent focal cerebral ischemia was induced in 87 awake monkeys (Macaca mulatta and Macaca fasicularis) by transorbital snare ligation of the middle cerebral artery (MCA) and neuropathological evaluation was carried out two weeks later. The size, location and histology of lesions varied within each time-period of MCA occlusion. However, most animals that underwent long-term ischemia (eight hours to permanent) had a single, confluent infarct involving deep and sometimes cortical structures. These animals had total necrosis chracterized by: 1. indiscriminate involvement of white and gray matter, 2. relatively sharp margins containing astrocytic and mononuclear cells, 3. an inner zone of liquefaction, infiltrated with fat-laden macrophages and newly formed blood vessels. Animals that underwent moderate to short-term ischemia (30 minutes to four hours) showed multiple, non-confluent deep infarcts. These animals had selective necrosis characterized by: 1. involvement of gray matter and relative sparing of white matter, 2. poorly circumscribed, multiple and often perivascular lesions with incomplete tissue destruction, 3. preferential loss of neurons and proliferation of reactive astrocytes and microglia.

Abstract: Objective: To describe indications and surgical techniques for embolization of cavernous sinus-dural fistulas (CDF) by passing platinum coils through a cannulated superior ophthalmic vein based on our clinical experience. Design: Retrospective clinical review. Setting: University tertiary referral hospital and eye institute. Patients: Over a 3-year period, 10 consecutive patients with CDF and progressive orbital congestion underwent transvenous embolization. All patients had a dilated superior ophthalmic vein. All 10 patients had indications for treatment of fistulas on the basis of progressive glaucoma refractory to medical management, venous stasis retinopathy with retinal ischemia, optic neuropathy, diplopia, exophthalmos with exposure keratopathy, cortical venous congestion with risk for intracranial hemorrhage, or a combination of these findings. Intervention: Nine of the 10 patients underwent anterior orbitotomy via a lid-crease or sub-brow incision with cannulation of the ipsilateral superior ophthalmic vein and embolization of the cavernous sinus with platinum coils, following an unsuccessful transarterial embolization. One patient underwent a primary transvenous embolization. Main Outcome Measures: Successful closure of the fistula on angiography, return of baseline visual acuity, normalization of postoperative intraocular pressure, and cosmetically acceptable cutaneous scar. Results: All 10 patients had prompt resolution of symptoms and halt of progressive visual loss following occlusion of the fistulas. Two patients had no flow in the anterior superior ophthalmic vein on angiography suggesting thrombosis, yet the superior ophthalmic vein was easily accessed in the anterior orbit, and transvenous embolization was successfully performed. In 2 additional patients with nondilated superior ophthalmic veins, we were unable to gain surgical access and in 1 case severe bleeding occurred during attempted access of the small vein. Conclusions: When performed by an experienced orbital surgeon and neuroradiology team, transvenous embolization of CDF via a dilated anterior superior ophthalmic vein is a technically straightforward, safe, and effective treatment for CDF and perhaps should be employed as primary therapy in cases with progressive orbital congestive symptoms. If the superior ophthalmic vein is not dilated or if it is located deep in the orbit, transorbital venous access may not be possible.