Drilling of the marginal tubercle to enhance exposure via mini pterional approach: An anatomical study and clinical series of 25 sphenoid wing meningiomas

Abstract INTRODUCTION Due to the advent of endovascular techniques, modern series of surgically treated posterior communicating (Pcom) aneurysms have shown a tendency towards higher complexity and more technical difficulties. The pretemporal approach was described as a valuable extension to the pterional approach in treating basilar apex aneurysms. Its use for clipping of ruptured Pcom aneurysms was associated with decreased ischemic complications. However, its anatomical advantages for Pcom aneurysm surgery have not been previously analyzed. METHODS Six cadaveric heads (12 sides) underwent a sequential dissection, starting with a pterional craniotomy, and then extended to a pretemporal transclinoidal approach. In each step, the following variables were measured, taking the origin of Pcom as a focal point: (1) exposed length of the internal carotid artery (ICA) proximal to the Pcom artery, (2) exposed angular circumference of ICA at the origin of Pcom, (3) deep working area between the optic nerve and tentorium/oculomotor nerve, (4) superficial working area, (5) depth of the exposure and the (6) fronto-temporal (superior posterolateral), and (7) orbito-sphenoidal (inferior anterolateral) angles of exposure. Clinical case examples are used to illustrate the advantages of the pretemporal approach. RESULTS Compared to the pterional craniotomy, the pretemporal transclinoidal approach increased the exposed length of the proximal ICA from 3.3 to 11.7 mm (P = .0001), and its circumference from 5.1 to 7.8 mm (P = .0003), allowing a 210-degree view of the ICA (vs 137.9). The deep and superficial working areas also significantly widened from 53.7 to 92.4 mm2 (P = .0048) and 252.8 to 418.2 mm2 (P = .0001), respectively; while the depth of the exposure was equivalent. The frontotemporal and the sphenosylvian angles increased on average by 17 (P = .0006) and 10 (P = .0037) degrees, respectively. The clinical case examples demonstrate the visual, technical and strategic advantages of the pretemporal approach as a consequence of its anatomical exposure. CONCLUSION The pretemporal approach can be useful for complex Pcom aneurysms by providing easier proximal control, wider working space, aneurysm visualization, and more versatile clipping angles. The enhanced exposure potentially results in a higher rate of complete aneurysm obliteration and complication avoidance.

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Anatomical study of the superior orbital fissure as seen during a pterional approach

Journal of Neurosurgery ◽

10.3171/jns.2007.106.1.151 ◽

2007 ◽

Vol 106 (1) ◽

pp. 151-156 ◽

Cited By ~ 13

Author(s):

Mario Ammirati ◽

Antonio Bernardo

Keyword(s):

Anatomical Study ◽

Pterional Approach ◽

Superior Orbital Fissure ◽

Specific Sequence ◽

Anterior Portion ◽

Important Landmark ◽

Controlled Exposure ◽

Surrounding Areas ◽

Brain Retraction ◽

Good Exposure

Object The superior orbital fissure (SOF) is an important landmark in the neurosurgical pterional approach, but the anatomical features of the SOF and the procedures necessary to fully expose it and its contents have not been detailed. Although the pterional approach is commonly used during skull base or vascular surgery by neurosurgeons who may already be familiar with its nuances and anatomical relationships to the SOF, this knowledge may also be useful to the wider neurosurgical community. The authors describe the spatial relationships of the contents of the SOF and suggest a specific sequence of steps for exposing the SOF region in a pterional approach. Methods Using standard microsurgical equipment and instruments, the authors performed 20 pterional approaches in 10 embalmed cadaver heads in which the vascular systems had been injected with colored material. Five sequential steps were delineated for approaching and dissecting the SOF and its contents: 1) drilling the sphenoidal ridge, anterior clinoidal process, and part of the greater and lesser wings of the sphenoid; 2) resecting the dural bridge; 3) detaching the hemispheric dura mater, thereby exposing the anterior portion of the cavernous sinus and the neural component entering the SOF; 4) identifying and dissecting the extraanular structures; and 5) opening the anulus of Zinn and identifying its neural constituents. Conclusions Knowing the 3D relationships of the contents of the SOF encountered in the pterional approach enables safe neurosurgical access to the area. The proposed sequence of steps allows a controlled exposure of the SOF and surrounding areas. Untethering the frontotemporal lobe by transecting the dural bridge connecting the dura to the perior-bita allows good exposure of the basal frontotemporal lobes, both intra- and extradurally, and reduces brain retraction.

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Segmental Gracilis Free Flap Based on Secondary Pedicles: Anatomical Study and Clinical Series

Plastic & Reconstructive Surgery ◽

10.1097/01.prs.0000130965.99546.15 ◽

2004 ◽

Vol 114 (3) ◽

pp. 684-691 ◽

Cited By ~ 14

Author(s):

Pedro C. Cavadas ◽

Juan R. Sanz-Giménez-Rico ◽

Luis Landín ◽

Francisco Martínez-Soriano

Keyword(s):

Free Flap ◽

Anatomical Study ◽

Clinical Series

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Contralateral C7 to C7 nerve root transfer in reconstruction for treatment of total brachial plexus palsy: anatomical basis and preliminary clinical results

Journal of Neurosurgery Spine ◽

10.3171/2018.3.spine171251 ◽

2018 ◽

Vol 29 (5) ◽

pp. 491-499 ◽

Cited By ~ 6

Author(s):

Guo-Bao Wang ◽

Ai-Ping Yu ◽

Chye Yew Ng ◽

Gao-Wei Lei ◽

Xiao-Min Wang ◽

...

Keyword(s):

Brachial Plexus ◽

Nerve Root ◽

Anatomical Study ◽

Nerve Transfer ◽

Pectoralis Major ◽

Elbow Extension ◽

Brachial Plexus Palsy ◽

Pectoral Nerve ◽

Clinical Series

OBJECTIVEContralateral C7 (CC7) nerve root has been used as a donor nerve for targeted neurotization in the treatment of total brachial plexus palsy (TBPP). The authors aimed to study the contribution of C7 to the innervation of specific upper-limb muscles and to explore the utility of C7 nerve root as a recipient nerve in the management of TBPP.METHODSThis was a 2-part investigation. 1) Anatomical study: the C7 nerve root was dissected and its individual branches were traced to the muscles in 5 embalmed adult cadavers bilaterally. 2) Clinical series: 6 patients with TBPP underwent CC7 nerve transfer to the middle trunk of the injured side. Outcomes were evaluated with the modified Medical Research Council scale and electromyography studies.RESULTSIn the anatomical study there were consistent and predominantly C7-derived nerve fibers in the lateral pectoral, thoracodorsal, and radial nerves. There was a minor contribution from C7 to the long thoracic nerve. The average distance from the C7 nerve root to the lateral pectoral nerve entry point of the pectoralis major was the shortest, at 10.3 ± 1.4 cm. In the clinical series the patients had been followed for a mean time of 30.8 ± 5.3 months postoperatively. At the latest follow-up, 5 of 6 patients regained M3 or higher power for shoulder adduction and elbow extension. Two patients regained M3 wrist extension. All regained some wrist and finger extension, but muscle strength was poor. Compound muscle action potentials were recorded from the pectoralis major at a mean follow-up of 6.7 ± 0.8 months; from the latissimus dorsi at 9.3 ± 1.4 months; from the triceps at 11.5 ± 1.4 months; from the wrist extensors at 17.2 ± 1.5 months; from the flexor carpi radialis at 17.0 ± 1.1 months; and from the digital extensors at 22.8 ± 2.0 months. The average sensory recovery of the index finger was S2. Transient paresthesia in the hand on the donor side, which resolved within 6 months postoperatively, was reported by all patients.CONCLUSIONSThe C7 nerve root contributes consistently to the lateral pectoral nerve, the thoracodorsal nerve, and long head of the triceps branch of the radial nerve. CC7 to C7 nerve transfer is a reconstructive option in the overall management plan for TBPP. It was safe and effective in restoring shoulder adduction and elbow extension in this patient series. However, recoveries of wrist and finger extensions are poor.

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