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Introduction  Olfactory groove meningiomas (OGMs) are often associated with loss of smell following resection. Loss of smell has a measurable impact on quality of life. Smell preservation has been previously described in open approaches for early stage or unilateral OGMs. Evidence of smell preservation in endoscopic approaches is lacking. Design  A multi-institutional retrospective review was performed on consecutive patients who underwent unilateral endoscopic endonasal resection of OGM. A gross total resection was achieved with preservation of the contralateral olfactory cleft and bulb. Olfactory function was assessed with a six-point olfactory symptom score and the Sniffin' Sticks 12-item smell identification test (SS-12). Contralateral olfactory bulb volume was measured on postoperative magnetic resonance imaging. Results  Four patients (age 42.0 ± 7.5, 75% female) were assessed. Olfactory function was assessed at 21.8 ± 5.6 months following surgery. All patients reported some degree of smell preservation (75% described a slight/mild impairment in smell or better). Olfactory identification was preserved with an SS-12 score of 9 ± 1.4 (anosmia defined as ≤6). The olfactory bulb volume was calculated to be 47.4 ± 15.9 mm 3 (normal >40 mm 3). Conclusion  Smell preservation is possible following unilateral endoscopic endonasal resection of carefully selected OGM. [ABSTRACT FROM AUTHOR]

Introduction Identifying the internal carotid artery (ICA) when managing petroclival and infratemporal fossa pathology is essential for the skull base surgeon. The vidian nerve and eustachian tube (ET) cartilage come together at the foramen lacerum, the vidian--eustachian junction (VEJ). The ICA position, relative to the VEJ is described. Methods Endoscopic dissection of adult fresh-frozen cadaver ICAs and a case series of patients with petroclival pathology were performed. The relationship of the VEJ to the ICA horizontal segment, vertical segment, and second genu was assessed. The distance of the ICA second genu to VEJ was determined in coronal, axial, and sagittal planes. The length of the vidian nerve and ET was measured from the pterygopalatine fossa (PPF) and nasopharyngeal orifice to the VEJ. Results In this study, 10 cadaver dissections (82.3 ± 6.7 years, 40% female) were performed. The horizontal petrous ICA was at or behind VEJ in 100%, above VEJ in 100%, and lateral to VEJ in80%. The vertical paraclival segment was ator behindVEJ in 100%, above in 100%, and medial in 100%. The second genu was at or behind VEJ in 100% (3.3 ± 2.4 mm), at or above in 100%(2.5 ± 1.6mm), andmedial in100%(3.4 ± 2.0mm). The VEJwas successfully used to locate the ICA in nine consecutive patients (53.3 ± 13.6 years, 55.6% female) where pathology was also present. The VEJ was 15.0 ± 6.0 mm from the ET and 17.4 ± 4.1 mm from the PPF. Conclusion The VEJ is an excellent landmark as it defines both superior and posterior limits when isolating the ICA in skull base surgery. [ABSTRACT FROM AUTHOR]

Background: Surgical landmarks for defining the level of the skull base during endoscopic sinus and skull base surgery (ESBS), e.g., the middle turbinate, may be distorted by tumor or previous surgery. The orbital floor is a valid fixed anatomic landmark for the white population, but it is not known if its use is useful for an Asian population. Objectives: To define fixed anatomic landmarks for ESBS in an Asian population and to compare the level of the skull base and its relation with anatomic landmarks between Asian and white populations. Methods: Computed tomographies performed on paranasal sinuses of Thai patients were retrospectively assessed. The distance between the nasal floor to four structures, the orbital floor, sphenoid planum, cribriform, and ethmoid roof, were measured. The level of skull base related to the orbital floor of an Asian population was compared with data of a white population from a previously published study. Results: A total of 150 Thai patients (300 paranasal sinus systems) were assessed and compared with 150 white patients. The orbital floor was always below the skull base (600 sides [100%]). When compared with white patients, the Asian patients had significantly higher mean (standard deviation [SD]) values: orbital floor (35.2 ± 3.4 mm versus 33.9 ± 3.0 mm; p < 0.001), ethmoid roof (49.3 ± 3.8 mm versus 48.4 ± 4.5 mm; p = 0.01), cribriform (46.4 ± 3.6 mm versus 44.0 ± 3.7 mm; p < 0.001), and sphenoid roof (45.7 ± 3.7 mm versus 44.9 ± 3.7 mm; p = 0.01). The Asian population had a mean (SD) longer distance from the orbital floor to the cribiform (11.2 ± 2.5 mm versus 10.1 ± 2.7 mm; p < 0.001), a shorter distance to the sphenoid roof (10.5 ± 3.3 mm versus 11.0 ± 2.9 mm; p = 0.03), and a similar distance to the ethmoid roof (14.1 ± 3.1 mm versus 14.5 ± 3.5 mm; p = 0.09). Conclusion: Although a statistical difference exists between racial groups, clinically, the orbital floor is a useful fixed anatomic landmark for ESBS for both Asian and white populations. [ABSTRACT FROM AUTHOR]

Objective To investigate the relevance of an endoscopic transnasal approach to the surgical treatment of paraophthalmic aneurysms. Setting Binasal endoscopic transplanum surgery was performed. Participants Seven cadaver heads were studied. Main Outcome Measures (1) Dimensions of the endonasal corridor, including the operative field depth, lateral limits, and the transplanum craniotomy. (2) The degree of vascular exposure. (3) Surgical maneuverability and access for clip placements. Results The mean operative depth was 90 ± 4 mm. The lateral corridors were limited proximally by the alar rim openings (29 ± 4 mm) and distally by the distance between the opticocarotid recesses (19 ± 2 mm). The mean posteroanterior distance and width of the transplanum craniotomy were 19 ± 2 mm and 17 ± 3 mm, respectively. Vascular exposure was achieved in 100% of cases for the clinoidal internal carotid artery (ICA), ophthalmic artery, superior hypophyseal artery, and the proximal ophthalmic ICA. Surgical access and clip placement was achieved in 97.6% of cases for vessels located anterior to the pituitary stalk (odds ratio [OR] 73.8; 95% confidence interval [CI] 7.66 to 710.8; p = 0.00). Conclusion The endoscopic transnasal approach provides excellent visualization of the paraclinoid region vasculature and offers potential surgical alternative for paraclinoid aneurysms. [ABSTRACT FROM AUTHOR]

Abstract: Although postoperative seizure is an acknowledged risk following transcranial surgery, the incidence of seizure after removal of intradural pathology via an expanded endoscopic endonasal approach is not well defined. The current study was performed to systematically review the risk of seizure in patients undergoing endoscopic endonasal skull base (EESB) surgery. Embase (1980 to 9 March 2012) and Medline (1950 to 9 March 2012) were searched using a search strategy designed to include any studies that report the perioperative outcomes following EESB surgery. Outcomes of patients undergoing a simple closure of cerebrospinal fluid fistulae or encephaloceles and transellar approaches for pituitary or intrasellar lesions were excluded because this review is focused on large skull base defects. A title search selected those articles relevant to clinical series on expanded endoscopic approaches. A subsequent search of abstracts selected for manuscripts of any report that documented the presence or absence of postoperative seizure. A total of 2234 manuscripts were selected initially and full text analysis produced 67 studies with extractable data regarding the perioperative outcomes for EESB surgery. Of these manuscripts, seven reported the incidence of seizure following EESB procedures. Two of these studies were excluded due to duplication of authorship and institutional data. The overall risk of postoperative seizure following EESB surgery was estimated at 1.1% (six of 530). Subgroup analyses of data revealed that the risk of seizure following an endoscopic endonasal to the anterior cranial base was 2.3% (one patient of 43). For a posterior cranial base approach, the risk of seizure was indeterminate due to deficiency of reporting in the current literature. We concluded that the risk of seizure following an EESB procedure appears to be low (1%). However, the lack of reporting on the incidence of seizures or the use of antiepileptic prophylaxis following EESB procedure is a key limitation. Future EESB studies will need to include seizure as an outcome to accurately define this risk. [Copyright &y& Elsevier]