Level I to III craniofacial approaches based on Barrow classification for treatment of skull base meningiomas: Surgical technique, microsurgical anatomy, and case illustrations
Department of Neurological Surgery, University of Wisconsin-Madison, 600 Highland Avenue, Madison, WI 53792, USA. Neurosurgical FOCUS
(Impact Factor: 2.11).
05/2011; 30(5):E5. DOI: 10.3171/2011.3.FOCUS1110
Although craniofacial approaches to the midline skull base have been defined and surgical results have been published, clear descriptions of these complex approaches in a step-wise manner are lacking. The objective of this study is to demonstrate the surgical technique of craniofacial approaches based on Barrow classification (Levels I-III) and to study the microsurgical anatomy pertinent to these complex craniofacial approaches.
Ten adult cadaveric heads perfused with colored silicone and 24 dry human skulls were used to study the microsurgical anatomy and to demonstrate craniofacial approaches in a step-wise manner. In addition to cadaveric studies, case illustrations of anterior skull base meningiomas were presented to demonstrate the clinical application of the first 3 (Levels I-III) approaches.
Cadaveric head dissection was performed in 10 heads using craniofacial approaches. Ethmoid and sphenoid sinuses, cribriform plate, orbit, planum sphenoidale, clivus, sellar, and parasellar regions were shown at Levels I, II, and III. In 24 human dry skulls (48 sides), a supraorbital notch (85.4%) was observed more frequently than the supraorbital foramen (14.6%). The mean distance between the supraorbital foramen notch to the midline was 21.9 mm on the right side and 21.8 mm on the left. By accepting the middle point of the nasofrontal suture as a landmark, the mean distances to the anterior ethmoidal foramen from the middle point of this suture were 32 mm on the right side and 34 mm on the left. The mean distance between the anterior and posterior ethmoidal foramina was 12.3 mm on both sides; the mean distance between the posterior ethmoidal foramen and distal opening of the optic canal was 7.1 mm on the right side and 7.3 mm on the left.
Barrow classification is a simple and stepwise system to better understand the surgical anatomy and refine the techniques in performing these complex craniofacial approaches. On the other hand, thorough anatomical knowledge of the midline skull base and variations of the neurovascular structures is crucial to perform successful craniofacial approaches.
Available from: Maria Piagkou
- "The mean OC-PEF distance in the present study was 4.3 mm. This is at the low end of that reported in the literature , where the mean OC-PEF distance ranges from 4.6 to 9.15 mm (Rontal et al., 1979; McQueen et al., 1995; Karakas¸et al., 2003; Akdemir et al., 2004; Avci et al., 2011). The knowledge that the optic nerve is located as close as 4.3 mm, but as far as 9 mm posteriorly to PEF, will help surgeons to avoid optic nerve injury. "
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ABSTRACT: The study determines the distribution patterns of ethmoidal foramina (EF) evaluate how they are affected by gender or bilateral asymmetry, and highlights the surgical implications on the anatomical landmarks of the orbit. Two hundred and forty-nine dry orbits were assessed. The number and pattern of EF were determined and distances between the anterior lacrimal crest (ALC), anterior (AEF) middle (MEF), posterior (PEF) ethmoidal foramina and between PEF and the optic canal (OC) were measured. The patterns of EF were classified as type I (single foramen) in 4 orbits (1.6%), type II (double foramina) in 152 (61%), type III (triple foramina) in 71 (28.5%), and type IV (multiple foramina) in 22 orbits (16.4%). Two orbits were found with five EF and a single orbit with six EF. A significant gender difference was observed for ALC-AEF distance (P ≤ 0.03), in males 23.53 ± 2.86 (20.67-26.39) versus females 22.51 ± 3.72 (18.79-26.23) mm. Bilateral asymmetry was observed for ALC-AEF distance (P ≤ 0.01). The distances ALC-AEF and ALC-PEF varied significantly according to EF classification (P ≤ 0.03 and P ≤ 0.02). The navigation ratio from ALC-AEF, AEF-PEF, and PEF-OC, in Greek population was "23-10-4 mm". A variation in the number of EF was found, ranging from 1 to 6, with the first report of sextuple EF. Although measures were generally consistent across genders and side, there are significant differences across ethnicities. These findings suggest that surgeons must consider population differences in determining the anatomical landmarks and navigation points of the orbit. Clin. Anat., 2013. © 2013 Wiley Periodicals, Inc.
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ABSTRACT: The expanded endoscopic endonasal (EEE) approach for the removal of olfactory groove (OGM) and tuberculum sellae (TSM) meningiomas is currently becoming an acceptable surgical approach in neurosurgical practice, although it is still controversial with respect to its outcomes, indications and limitations. Here we provide a review of the available literature reporting results with use of the EEE approach for these lesions together with our experience with the use of the endoscope as the sole means of visualization in a series of patients with no prior surgical biopsy or resection. Surgical cases between May 2006 and January 2013 were retrospectively reviewed. Twenty-three patients (OGM n=6; TSM n=17) were identified. In our series gross total resection (GTR) was achieved in 4/6 OGM (66.7%) and 11/17 (64.7%) TSM patients. Vision improved in the OGM group (2/2) and 8/11 improved in the TSM group with no change in visual status in the remaining three patients. Post-operative cerebrospinal fluid (CSF) leak occurred in 2/6 (33%) OGM and 2/17 (11.8%) TSM patients. The literature review revealed a total of 19 OGM and 174 TSM cases which were reviewed. GTR rate was 73% for OGM and 56.3% for TSM. Post-operative CSF leak was 30% for OGM and 14% for TSM. With careful patient selection and a clear understanding of its limitations, the EEE technique is both feasible and safe. However, longer follow-ups are necessary to better define the appropriate indications and ideal patient population that will benefit from the use of these newer techniques.
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ABSTRACT: Typically, the medial orbital wall contains an anterior ethmoidal foramen (EF) and a posterior EF, but may also have multiple EFs transmitting the arteries and nerves between the orbit and the anterior cranial fossa. The aim of this study is to determine a patient-friendly landmark of the medial orbital wall and to specify a precise location of the ethmoidal foramens (EF) in order to standardize certain anatomical marks as safe ethmoidal arteries. Orientation points on the anterior ethmoidal foramen (AEF), posterior ethmoidal foramen (PEF) and middle ethmoidal foramen (MEF) were investigated in 262 orbits. Using a software program, distances between each foramen and the midpoint of the anterior lacrimal crest (ALC), the optic canal (OC), and some important angles were measured. The EFs were identified as single in 0.8 %, double in 73.7 %, triple 24,4 % and quadruple in 1.1 % specimens. The mean distances between ALC and AEF, ALC and PEF and ALC and MEF were 27.7, 10.6, and 12.95 mm, respectively. The distances from ALC-AEF, AEF-PEF, and PEF-OC were 27.7 ± 2.8, 10.6 ± 3.3, 5.4 ± 1 mm. The angles from the plane of the EF to the medial border of the OC were calculated as 13.2° and 153°, respectively. The angle from the AEF to the medial border of the OC was based on the plane between the ALC and AEF was 132°. The occurrence of multiple EF with an incidence of 25 % narrows the borders of the safe region in the medial orbital wall. Safe distance of the ALC-EF was measured as 22.1 mm on medial wall. The line of the location of the EF was calculated 16.2 mm. In this study, it was possible to investigate the variability of the orbital orifice of the EF and the feasibility of the EA, to observe various angles of the orbital wall bones and to calculate the lengths of some parameters with the help of certain software.
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