Transorbital endoscopic approach for exposure of the sylvian fissure, middle cerebral artery and crural cistern: an anatomical study.

BACKGROUND: The availability of minimal access instrumentation and endoscopic visualization has revolutionized the field of minimally invasive skull base surgery. The transorbital endoscopic approach using an eyelid incision has been proposed as a new minimally invasive technique for the treatment of skull base pathology, mostly extradural tumors. Our study aims to evaluate the anatomical aspects and potential role of the transorbital endoscopic approach for exposure of the sylvian fissure, middle cerebral artery and crural cistern. METHODS: An anatomical dissection was performed in four freshly injected cadaver heads (8 orbits) using 0- and 30-degree endoscopes. First, an endoscopic endonasal medial orbital decompression was done to facilitate medial retraction of the orbit. An endoscopic transorbital approach through an eyelid incision, with drilling of the posterior wall of the orbit and lesser sphenoidal wing, was then performed to expose the sylvian fissure and crural cisterns. A stepwise anatomical description of the approach and visualized anatomy is detailed. RESULTS: A superior eyelid incision followed by orbital retraction provided a surgical window of approximately 1.2 cm (range 1.0-1.5 cm) for endoscopic transorbital dissection. The superior (SOF) and inferior (IOF) orbital fissures represent the medial limits of the approach and are identified in the initial part of the procedure. Drilling of the orbital roof (lateral and superior to the SOF), greater sphenoidal wing (lateral to the SOF and IOF) and lesser sphenoidal wing exposed the anterior and middle fossa dura. A square-shaped dural opening provided visualization of the posterior orbital gyri, sylvian fissure and temporal pole. Intradural dissection allowed exposure of the sphenoidal portion of the sylvian fissure, M1, MCA bifurcation and M2 branches and lenticulostriate perforators. Dissection of the medial aspect of the sylvian and carotid cisterns with a 30-degree endoscope allowed exposure of the mesial temporal lobe and crural cistern. CONCLUSIONS: The transorbital endoscopic approach allows successful exposure of the sphenoidal portion of the sylvian fissure and M1 and M2 segments of the middle cerebral artery. Angled endoscopes may provide visualization of the mesial temporal lobe and crural cistern. Although our anatomical study demonstrates the feasibility of intradural dissection and closure via an endoscopic transorbital approach, further studies are necessary to evaluate its role in the clinical scenario.

Limitations of the endonasal endoscopic approach in treating olfactory groove meningiomas. A systematic review.

OBJECTIVE: To review current management strategies for olfactory groove meningioma (OGM)s and the recent literature comparing endoscopic endonasal (EEA) with traditional transcranial (TCA) approaches. METHODS: A PubMed search of the recent literature (2011-2016) was performed to examine outcomes following EEA and TCA for OGM. The extent of resection, visual outcome, postoperative complications and recurrence rates were analyzed using percentages and proportions, the Fischer exact test and the Student's t-test using Graphpad PRISM 7.0Aa (San Diego, CA) software. RESULTS: There were 444 patients in the TCA group with a mean diameter of 4.61 (±1.17) cm and 101 patients in the EEA group with a mean diameter of 3.55 (± 0.58) cm (p = 0.0589). GTR was achieved in 90.9% (404/444) in the TCA group and 70.2% (71/101) in the EEA group (p < 0.0001). Of the patients with preoperative visual disturbances, 80.7% (21/26) of patients in the EEA cohort had an improvement in vision compared to 12.83%(29/226) in the TCA group (p < 0.0001). Olfaction was lost in 61% of TCA and in 100% of EEA patients. CSF leaks and meningitis occurred in 25.7% and 4.95% of EEA patients and 6.3% and 1.12% of TCA patients, respectively (p < 0.0001; p = 0.023). CONCLUSIONS: Our updated literature review demonstrates that despite more experience with endoscopic resection and skull base reconstruction, the literature still supports TCA over EEA with respect to the extent of resection and complications. EEA may be an option in selected cases where visual improvement is the main goal of surgery and postoperative anosmia is acceptable to the patient or in medium-sized tumors with existing preoperative anosmia. Nevertheless, based on our results, it seems more prudent at this time to use TCA for the majority of OGMs.

Transtubular excisional biopsy as a rescue for a non-diagnostic stereotactic needle biopsy-case report and literature review.

Stereotactic needle biopsy, a standard of care for acquiring deep-seated pathology, has limitations and risks in some situations. We present an uncommon case with basal ganglia dematiaceous mycetoma. Due to the firm consistency of the lesion, the initial stereotactic needle biopsy failed to provide a diagnosis. In a second operation, transtubular excisional biopsy was successfully performed to remove the entire mycetoma. We reviewed recent case series of transtubular approaches to deep-seated brain lesions and suggest this method could be a rescue for a non-diagnostic stereotactic needle biopsy and even may be the approach of choice in some cases.

Predictors and incidence of orthostatic headache associated with lumbar drain placement following endoscopic endonasal skull base surgery.

BACKGROUND: Orthostatic headache (OH) is a potential complication of lumbar drainage (LD) usage. The incidence and risk factors for OH with the use of lumbar drainage during endoscopic endonasal procedures have not been documented. OBJECTIVE: To investigate the incidence of post-procedure OHs associated with placement of LD in patients undergoing endoscopic endonasal procedures. METHODS: We prospectively noted the placement of LDs in a consecutive series of endoscopic endonasal skull base surgeries. Charts were retrospectively reviewed, and patients were divided into two groups: those with OH and those without. The patient demographics, drain durations, imaging findings of intracranial hypotension, pathologies and need for a blood patch were compared between the two groups. RESULTS: Two hundred forty-nine patients were included in the study. Seven patients (2.8%) suffered post-dural puncture OH, which was mild to moderate and disappeared 2-8 days (median 3 days) after treatment. Blood patches were used in four patients. Significant predisposing factors were age (33.0 vs. 53.5, P = 0.014) and a strong trend for female gender (85.7% vs. 47.9%, P = 0.062). BMI and drain duration were not significant. Postoperative intracranial hypotension was diagnosed radiographically in 43% of OH patients and in 5.4% of those without OH (P = 0.003). Four (1.6%) patients required treatment with an epidural blood patch. CONCLUSION: OH associated with intracranial hypotension in patients undergoing endoscopic endonasal procedures with LDs is an infrequent complication seen more commonly in young female patients. Radiographic signs of intracranial hypotension are a specific but not sensitive test for OH.

Cervical Dermal Sinus Tract: A Case Report and Comprehensive Literature Review.

The cervical and thoracic dermal sinuses are rare entities, conforming epithelium-lined tracts that extend from an opening in the skin through a corridor to the layers of the spinal cord. They are commonly detected in early childhood; however, adult reports are singularly rare, especially in cervical regions. We report a very unusual case of a 45-year-old Mexican female who developed progressive left-side weakness and dexterity suffered from childhood, getting worse in the last year. Physical examination revealed a soft, congenital round cystic lesion in the dorsal-midline skin at the level of C4-C5 vertebrae with no previous treatment received. MRI showed a dermal sinus tract at the C4 level from the skin tethering to the spinal cord and syringomyelia. CT scan showed a dysraphism corresponding to spina bifida at the C4 level and an incomplete closure at the C3 and C5 vertebrae. We surgically managed the lesion by microscopic resection with C3-C5 laminectomy preserving strength and sensitivity. Follow-up MRI showed no residual lesion and contained fistula with no further complications. Cervical dermal sinus lesions are unusual entities, even less prevalent in adulthood. It represents a possible delay in diagnosis and an increased rate of complications. Early suspicion of the condition is required to make an accurate diagnosis since it is a potentially treatable lesion with a high risk of sequelae without surgical treatment.

Sodium Fluorescein Videoangiography as an Adjunct to Resection of Cerebral Arteriovenous Malformations.

OBJECTIVE: To characterize dynamic changes of arteriovenous malformation using a microscope-integrated technique at the moment of performing intraoperative fluorescein videoangiography (FL-VAG) at each of the resection phases. METHODS: We prospectively recruited 12 patients with arteriovenous malformations and used FL-VAG as an ancillary technique for resection of the lesion. We analyzed transit time (TT) of FL in arterial feeders (arterial transit time [TTa]) and draining veins (venous transit time [TTv]) during the different stages of resection. To achieve this, we recorded 3 values of TT of FL (TTa, initial TTv, final TTv); when final TTv was markedly slower than initial TTv, we hypothesized that the nidus was devascularized enough and could be safely removed. RESULTS: No mortality or morbidity was related to use of FL. In most cases, TT values of arterial feeders and draining veins allowed an easier distinction between them. At advanced stages of resection, FL-VAG assessed increase in TTv (venous blood slower or absent), suggesting that most feeding arteries had been obliterated, indicating the appropriate moment for nidus removal. Optimal dose of FL was a 75-mg bolus followed by injection of 20 mL of saline solution. CONCLUSIONS: FL-VAG allows a distinction of normal from abnormal flow in draining vessels and might help the surgeon to decide when the nidus can be safely removed. This is the first study prospectively evaluating this technique, and it proposes an ideal dose for brain arteriovenous malformation surgery, in contrast to doses used in tumor cases.

Reoperation for growth hormone-secreting pituitary adenomas: report on an endonasal endoscopic series with a systematic review and meta-analysis of the literature.

OBJECTIVE Surgery is generally the first-line therapy for acromegaly. For patients with residual or recurrent tumors, several treatment options exist, including repeat surgery, medical therapy, and radiation. Reoperation for recurrent acromegaly has been associated with poor results, with hormonal control usually achieved in fewer than 50% of cases. Extended endonasal endoscopic approaches (EEAs) may potentially improve the results of reoperation for acromegaly by providing increased visibility and maneuverability in parasellar areas. METHODS A database of all patients treated in the authors' center between July 2004 and February 2016 was reviewed. Cases involving patients with acromegaly secondary to growth hormone (GH)-secreting adenomas who underwent EEA were selected for chart review and divided into 2 groups: first-time surgery and reoperation. Disease control was defined by 2010 guidelines. Clinical and radiological characteristics and outcome data were extracted. A systematic review was done through a MEDLINE database search (2000-2016) to identify studies on the surgical treatment of acromegaly. Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the included studies were reviewed for surgical approach, tumor size, cavernous sinus invasion, disease control, and complications. Cases were divided into reoperation or first-time surgery for comparative analysis. RESULTS A total of 44 patients from the authors' institution were included in this study. Of these patients, 2 underwent both first-time surgery and reoperation during the study period and were therefore included in both groups. Thus data from 46 surgical cases were analyzed (35 first-time operations and 11 reoperations). The mean length of follow-up was 70 months (range 6-150 months). The mean size of the reoperated tumors was 14.8 ± 10.0 mm (5 micro- and 6 macroadenomas). The patients' mean age at the time of surgery was younger in the reoperation group than in the first-time surgery group (34.3 ± 12.8 years vs 49.1 ± 15.7 years, p = 0.007) and the mean preoperative GH level was also lower (7.7 ± 13.1 µg/L vs 25.6 ± 36.8 µg/L, p = 0.04). There was no statistically significant difference in disease control rates between the reoperation (7 [63.6%] of 11) and first-time surgery (25 [71.4%] of 33) groups (p = 0.71). Univariate analysis showed that older age, smaller tumor size, lower preoperative GH level, lower preoperative IGF-I level, and absence of cavernous sinus invasion were associated with higher chances of disease control in the first-time surgery group, whereas only absence of cavernous sinus invasion was associated with disease control in the reoperation group (p = 0.01). There was 1 case (9%) of transient diabetes insipidus and hypogonadism and 1 (9%) postoperative nasal infection after reoperation. The systematic review retrieved 29 papers with 161 reoperation and 2189 first-time surgery cases. Overall disease control for reoperation was 46.8% (95% CI 20%-74%) versus 56.4% (95% CI 49%-63%) for first-time operation. Reoperation and first-time surgery had similar control rates for microadenomas (73.6% [95% CI 32%-98%] vs 77.6% [95% CI 68%-85%]); however, reoperation was associated with substantially lower control rates for macroadenomas (27.5% [95% CI 5%-57%] vs 54.3% [95% CI 45%-62%]) and tumors invading the cavernous sinus (14.7% [95% CI 4%-29%] vs 38.5% [95% CI 27%-50%]). CONCLUSIONS Reoperative EEA for acromegaly had results similar to those for first-time surgery and rates of control for macroadenomas that were better than historical rates. Cavernous sinus invasion continues to be a negative prognostic indicator for disease control; however, results with EEA show improvement compared with results reported in the prior literature.

Transorbital endoscopic eyelid approach for resection of sphenoorbital meningiomas with predominant hyperostosis: report of 2 cases.

Sphenoorbital meningiomas (SOMs) are slow-growing tumors that originate from the sphenoidal wing and are associated with visual deterioration, extrinsic ocular movement disorders, and proptosis caused by hyperostosis of the lateral wall of the orbit. In some cases, the intracranial component is quite small or "en plaque," and the majority of the symptoms arise from adjacent hyperostosis. Craniotomy has traditionally been the standard of care, but new minimally invasive multiportal endoscopic approaches offer an alternative. In the current study, the authors to present their experience with the transorbital endoscopic eyelid approach for the treatment of 2 patients with SOMs and sphenoid wing hyperostosis. Clinical and radiological data for patients with SOMs who underwent a transorbital endoscopic eyelid approach were retrospectively reviewed. Surgical technique and clinical and radiographic outcomes were analyzed. The authors report the cases of 2 patients with SOMs and proptosis due to sphenoid wing hyperostosis. One patient underwent prior craniotomy to debulk the intracranial portion of the tumor, and the other had a minimal intracranial component. Both patients were discharged 2 days after surgery. MR images and CT scans demonstrated a large debulking of the hyperostotic bone. Postoperative measurement of the proptosis with the aid of an exophthalmometer demonstrated significant reduction of the proptosis in one of the cases. Persistence of intraconal tumor in the orbital apex limited the efficacy of the procedure in the other case. A review of the literature revealed 1 publication with 3 reports of the transorbital eyelid approach for SOMs. No measure of relief of proptosis after this surgery had been previously reported. The transorbital endoscopic approach, combined with endonasal decompression of the medial orbit, may be a useful minimally invasive alternative to craniotomy in a subset of SOMs with a predominantly hyperostotic orbital wall and minimal intracranial bulky or merely en plaque disease. In these cases, relief of proptosis and optic nerve compression are the primary goals of surgery, rather than gross-total resection, which may have high morbidity or be unachievable. In cases with significant residual intraconal tumor, orbital bone removal alone may not be sufficient to reduce proptosis.