Lateral orbital wall approach to the cavernous sinus: laboratory investigation

Object. Lesions of the cavernous sinus remain a technical challenge. The most common surgical approaches involve some variation of the standard frontotemporal craniotomy. Here, the authors describe a surgical approach to access the cavernous sinus that involves the removal of the lateral orbital wall. Methods. To achieve exposure of the cavernous sinus, a lateral canthal incision is performed, and the lateral orbital rim and anterior lateral wall are removed, for later replacement at closure. The posterior lateral orbital wall is removed to the region of the superior and inferior orbital fissures. With reflection of the dural covering of the lateral cavernous sinus and removal of the anterior clinoid process, the cavernous sinus is exposed. Results. Exposure and details of the procedure were derived from anatomical study in cadavers. After the approach, with removal of the anterior clinoid process, the entire cavemous sinus from the superior orbital fissure anteriorly to the Meckel cave posteriorly is exposed. More exposure to the lateral middle fossa, foramen spinosum, and petrous carotid artery is obtained by further removal of the lateral sphenoid wing. An illustrative case example for approaching a cavernous sinus meningioma is presented. Conclusions. The translateral orbital wall approach provides a simple, rapid approach for lesions with primary or secondary involvement of the cavernous sinus. Advantages of this simple, extradural approach include the lack of brain retraction and no interruption of the temporalis muscle.

J Neurosurg / Volume 116 / April 2012 J Neurosurg 116:755-763, 2012 755 LESIONS in the cavernous sinus were long considered inoperable because of the danger of bleeding from the venous plexus or the injury to important neuro-vascular structures, such as the ICA, the abducent nerve, and the sympathetic nerves. During the past 2 decades, however, meticulous microsurgical studies have described numerous approaches with acceptable morbidity and mor-tality. 1,2,7-9,11,13-15,19,21,23,24 Nevertheless, controversy related to the optimal approach for different kinds of lesions con-tinues, and the cavernous sinus is still a challenging and unfamiliar place for many neurosurgeons. In the present study, we describe a novel surgical ap-proach to access the cavernous sinus that involves the re-moval of the lateral orbital wall. This translateral orbital wall approach offers a quick, relatively easy, and less inva-sive access to the cavernous sinus with adequate exposure, obviating a formal craniotomy that is needed in previously described approaches. The approach also provides excel-lent cosmesis with a lateral orbital canthotomy skin inci-sion. Methods Materials We performed 12 procedures using standard micro-surgical equipment and instruments in 5 fresh uninject- heads. The specimens were maintained in surgical position microscope and an electric drill with cutting and diamond burs were used in all dissections. Morphometric distances between the key anatomical landmarks were measured. Lateral orbital wall approach to the cavernous sinus Laboratory investigation TAMER ALTAY, M.D.,1 BHUPENDRA C. K. PATEL, M.D., F.R.C.S.,2 AND WILLIAM T. COULDWELL, M.D., PH.D.1 1Department of Neurosurgery, Clinical Neurosciences Center, and 2Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah Object. Lesions of the cavernous sinus remain a technical challenge. The most common surgical approaches involve some variation of the standard frontotemporal craniotomy. Here, the authors describe a surgical approach to access the cavernous sinus that involves the removal of the lateral orbital wall. Methods. To achieve exposure of the cavernous sinus, a lateral canthal incision is performed, and the lateral orbital rim and anterior lateral wall are removed, for later replacement at closure. The posterior lateral orbital wall is ! cavernous sinus and removal of the anterior clinoid process, the cavernous sinus is exposed. Results. Exposure and details of the procedure were derived from anatomical study in cadavers. After the ap- " # " anteriorly to the Meckel cave posteriorly is exposed. More exposure to the lateral middle fossa, foramen spinosum, and petrous carotid artery is obtained by further removal of the lateral sphenoid wing. An illustrative case example for approaching a cavernous sinus meningioma is presented. Conclusions. The translateral orbital wall approach provides a simple, rapid approach for lesions with primary or secondary involvement of the cavernous sinus. Advantages of this simple, extradural approach include the lack of brain retraction and no interruption of the temporalis muscle. (DOI: 10.3171/2011.12.JNS111251) KEY WORDS Abbreviations used in this paper: GSPN = greater superficial petrosal nerve; ICA = internal carotid artery. This article contains some figures that are displayed in color on line but in black and white in the print edition. T. Altay, B. C. K. Patel, and W. T. Couldwell 756 J Neurosurg / Volume 116 / April 2012 Surgical Procedure The head is positioned as in a pterional approach, rotated 30 to the contralateral side (Fig. 1). A transverse lateral canthotomy incision is made, extending from the lateral epicanthus 2 cm laterally as far down as the lateral orbital ridge (Fig. 2A). Next, the periosteum is dissected off of the lateral orbital rim until the orbitozygomatic and frontoorbital junctions are exposed. Then, the temporalis muscle and the periorbita on both sides of the lateral orbital wall are dissected (Fig. 2B). The dissection on these planes is continued intraorbitally to the lateral projection of the "" "$ of temporal bone along with the orbitotemporal junction is cleared off the temporalis muscle. Attention is paid so as not to tear the periorbita during the dissection. Once the intended exposure is achieved, the globe and temporalis muscle are gently retracted medially and laterally, respec-tively. A 2-cm segment of lateral orbital rim, along with the anterior lateral orbital wall, is cut using a rotating drill or oscillating saw (Fig. 2C). The cut line is extended to the " - tion posteriorly, and up to the lower margin of the sphenoid ridge superiorly. Then, a high-speed drill is used to drill the lateral orbital wall and release the lateral orbital bone and rim. % " opened wide and its inferior edge, which constitutes part of the lateral orbital wall, is removed. The initial craniocaudal borders are the base of the middle fossa inferiorly and the lesser sphenoid wing and the anterior clinoid process supe-riorly. A dissection plane is created between the dura of the temporal lobe and the lateral wall of the cavernous sinus, and contains the meningoorbital artery at its lateral end. This plane is followed sharply posteriorly, inferiorly, and laterally, until the entire lateral wall of the cavernous sinus is exposed. The extradural removal of the anterior clinoid process is accomplished easily, following the lateral orbital wall with drilling down to the optic strut and thinning the lateral wall of the optic canal. After the anterior clinoid process is detached from the superomedial part of the optic canal and the optic strut and removed, the clinoid segment of the ICA, the proximal and dural rings, and the superior wall of the cavernous sinus are exposed (Figs. 3 and 4). The initial approach with removal of the lateral or-bital wall alone is limited by the temporal bone laterally, which prevents complete access to the V3 segment of the trigeminal nerve, the foramen ovale, and the petrous ca-rotid artery and lateral temporal fossa (Fig. 5). To access these surgical territories by a more extended version of the approach, an additional 0.5-cm-wide segment of the anterior middle fossa (greater wing of the sphenoid) is removed laterally. This further facilitates posterolateral dissection and expands the limits of this approach to the foramina ovale and spinosum, the GSPN, and the petrous carotid artery (Figs. 6 and 7). At this stage, to assess the intradural access through this approach, we opened the dura and excised the distal dural ring. This provided us complete visualization of the clinoid and supraclinoid segments of the ICA as well as the direct takeoff of the posterior communicating artery (Figs. 8 and 9). The retractions used throughout the procedure are limited to modest globe retraction medially and to the temporalis muscle laterally. Suction assistance is the only FIG. 1. Left: Illustration showing the lateral orbital rim and wall to be removed for the translateral orbital approach to the cav-ernous sinus. Right: Illustration showing the parasellar area and middle fossa structures after removal of the lateral orbital rim and wall in the translateral orbital approach. Printed with permission from KTB Studios, LLC. J Neurosurg / Volume 116 / April 2012 Lateral orbital wall approach to the cavernous sinus 757 retraction needed for the intracranial phase of the proce-dure. Closure is simple. The lateral orbital rim is replaced using cranial repair mesh or Medpor (Stryker Corp.) placed between the globe and the temporalis muscle. This is op-tional if the periorbita is left intact. The frontoorbital and orbitozygomatic junctions are bridged by the removed piece of the lateral orbital rim attached by titanium mini-plates. Finally, the layers of the transverse skin incision are sutured in a subcuticular fashion for optimal cosmetic re-sults. Morphometric Analysis The distances between the anatomical landmarks are shown in Table 1. The average distances from the fron-tozygomatic suture to the superior edge of the zygomatic arch, and from the mid-lateral orbital wall to the edge of the greater sphenoid wing, which are the vertical and hori-zontal extensions of the bone opening, were 20.8 0.73 FIG. 2. Cadaver dissection demonstrating the surgical incision (A), exposure of the lateral orbital rim (B), and removal of the lateral orbital rim and anterior lateral orbital wall (C). Note the gentle retraction of the temporalis muscle and the orbital structures. FIG. 3. Cadaver dissection after lateral orbital removal, demonstrat-ing initial exposure of the anterior cavernous sinus and anterior clinoid process (ACP). III = oculomotor nerve; IV = trochlear nerve. FIG. 4. After removal of the anterior clinoid process, the intradural carotid artery is exposed after opening the distal dural ring (DDR). The temporal dura mater is dissected off the lateral wall of the cavernous sinus. Then, the dura is opened and the distal dural ring is excised. T. Altay, B. C. K. Patel, and W. T. Couldwell 758 J Neurosurg / Volume 116 / April 2012 and 12.0 1.08 mm, respectively. The distance from the periorbita at the greater sphenoid wing level to the edge of the greater sphenoid wing was 15.4 1.37 mm. We cal-culated the average working area to be approximately 3.6 cm2, based on a rectangular shape. The average retraction of the globe was 9.25 2.17 mm at the level of the lateral orbital rim. The distance from the base of the greater sphe- # was 13.0 0.90 mm. The working depth to the anterior cavernous sinus was calculated as the sum of the distances from the mid-lateral orbital rim to the base of the greater sphenoid wing and the base of the greater sphenoid wing to the posterior edge of the foramen rotundum, which aver-aged 50.4 1.69 mm. The deepest point reached was at the petrous edge at the trigeminal impression. This averaged 67.6 1.62 mm. In the extended version of the approach, only the hori-zontal extension of the bone opening differed from the initial exposure, averaging 19.16 2.12 mm. The average difference was 7.08 2.53 mm. The distance from the peri-orbita to the edge of greater sphenoid wing was 22.4 2.02 mm. We calculated the average working area to be 46.5 cm2 based on a rectangular shape. Anatomical Observations & # found when either of the following 2 anatomical markers was noted: a perpendicular line to the midpoint of the seg-ment of the removed piece of the lateral orbital rim, or the trajectory immediately below and parallel to the sphenoid ridge. Retraction of the orbital contents was not required more than 1 cm, and this permitted immediate establish-ment of the plane between the temporal dura and the peri-orbita following the cut of the dural fold in the superior or- This also allowed us to use a more lateral angle, avoiding a FIG. 5. A more inferior exposure enables clear visualization of the trigeminal nerve. FIG. 6. Cadaver dissection (left) and illustration (right) showing exposure of the intradural carotid artery with the posterior com-municating artery takeoff after exposure of the cavernous sinus. The oculomotor and trochlear nerves are exposed. Both clinoid and intradural segments of the ICA are also seen. CN = cranial nerve. Illustration used with permission from KTB Studios, LLC. J Neurosurg / Volume 116 / April 2012 Lateral orbital wall approach to the cavernous sinus 759 Removing the anterior clinoid process facilitated the excision of the distal dural ring and opening the dura in the parasellar area. Once the dura was opened, the optic nerve, the clinoid and supraclinoid segments of the ICA, and the posterior communicating artery takeoff were visualized. The takeoff of the ophthalmic artery was hidden behind the ICA and could not be visualized in any of our cadaver dissections in earlier steps of the procedure. It could only be seen when the clinoid segment of the ICA was mobi-lized after the excision of the distal dural ring. Our approach was satisfactory to reach the entire cav- the Meckel cave posteriorly, but it had limitations in ex-posing the middle fossa structures, including the foramina ovale and spinosum, the GSPN, and the petrous carotid artery. Expansion of the approach into the so-called "ex-tended version" by removing an additional part of the ante-rior greater sphenoid wing laterally enough to expose these structures achieved the expected goal. Lateral canthotomy followed by reconstruction of the lateral orbital wall and replacement of the orbital rim pro-vided good cosmesis. FIG. 7. A more inferior trajectory demonstrates the lateral aspects of all 3 branches of the trigeminal nerve and gasserian ganglion. Illustration used with permission from KTB Studios, LLC. FIG. 8. Cadaver dissection (left) and illustration (right) depicting the entrance to the cavernous sinus through its lateral wall between V1 and V2. The V1 segment is retracted to expose the proximal part of the cavernous carotid artery and the abducent nerve coursing lateral to it. Illustration used with permission from KTB Studios, LLC. T. Altay, B. C. K. Patel, and W. T. Couldwell 760 J Neurosurg / Volume 116 / April 2012 This 70-year-old man presented with a 5-year history of progressive visual loss in his right eye. Ophthalmologi-cal evaluation demonstrated some decline in his visual acuity and a small superior right temporal and nasal visual # - hancing lesion of the right cavernous sinus with optic canal involvement (Fig. 10). A lateral orbitotomy approach was used to decompress the optic nerve, remove the anterior clinoid process and the lateral wall of the cavernous sinus, and obtain a biopsy specimen of the lesion (Video 1). VIDEO 1. Intraoperative video demonstrating the use of the translateral orbital approach in a 70-year-old man who had an enhancing lesion of the right cavernous sinus with optic canal involvement. Illustrations are used with permission from KTB Studios, LLC. Click here to view with Windows Media Player. Click here to view with Quicktime. Postoperative CT scans demonstrated the extent of bone removal (Fig. 11). Postoperatively, the patient had an un- # - erative day with stable vision. Pathological analysis identi- '%*+& will be monitored with serial observations, including MR imaging studies and ophthalmological evaluations every 6 months. /# - ported by Browder4 and later by Parkinson and Ramsay,18 the belief that the cavernous sinus was inoperable has been abandoned, and courageous attempts have been made to surgically treat lesions located in this area. Numerous ap-proaches have been developed that are based on the phi-losophy of more extensive bone removal with the aim of minimizing cerebral retraction. <>26-28 popularized the transsyl-vian approach to lesions in the sellar and parasellar regions. They used the frontotemporal craniotomy with frontoor-bital and sphenoidal osteotomy, the so-called "pterional" craniotomy, to take advantage of the cisternal route. This FIG. 9. Cadaver dissection (left) and illustration (right) of the "extended version" of the translateral orbital approach. The me-dial temporal fossa is followed as far back as the Meckel cave and the petrous ridge. The posterior fossa dura is opened above the superior petrosal sinus, revealing the superior cerebellar artery in the posterior fossa. Illustration used with permission from KTB Studios, LLC. TABLE 1: Morphometric analysis of the surgical exposure* Key Anatomical Structures Mean Length (mm)† Range (mm) FZS to superior edge of ZA (vertical extension) 20.8 0.73 20-22 mid-LOR to base of GSW 22.5 0.79 21-24 mid-LOW to edge of GSW (transverse extension) 12.0 1.08 10-14 mid-LOW to edge of GSW (transverse extension)‡ 19.25 2.05 17-23 base of GSW to lat end of SOF 13.0 0.90 12-15 junction of LOR/superior edge of ZA to lat end of IOF 17.6 1.55 15-19 base of GSW to posterior edge of FR 27.9 0.90 27-29 base of GSW to tip of ACP 34.9 0.79 34-36 base of GSW to tip of PCP 40.5 1.08 38-42 base of GSW to posterior edge of FO 37.1 1.11 36-39 base of GSW to Meckel cave 41.9 1.16 40-43 base of GSW to petrous edge at trigeminal impression 45.1 0.83 44-46 * ACP = anterior clinoid process; FO = foramen ovale; FR = foramen rotundum; FZS = frontozygomatic suture; GSW = greater sphenoid eral orbital wall; PCP = posterior clinoid process; SOF = superior orbital !!"# † Presented as ± SD. ‡ Extended version. J Neurosurg / Volume 116 / April 2012 Lateral orbital wall approach to the cavernous sinus 761 most anterior and anterolateral approaches for various pathological conditions. Hakuba et al.13 reported 19 cases in which they used 4 mainly intradural approaches for the treatment of tumors and vascular lesions in this region un-der normothermic conditions. In their series, entry to the cavernous sinus was achieved through the lateral wall at the Parkinson triangle via the frontotemporal or subfron- & - bined transpetrosal-subtemporal approach to tumors in the posterior cavernous sinus extending to the petroclival area. Shortly after that successful outcome, Dolenc7-9 pioneered the intra- and extradural approach to the cavernous sinus, which combined a pterional approach with a subtemporal approach and exposure of the intrapetrous part of the ICA when necessary. After removal of the anterior clinoid pro-cess, the cavernous sinus is entered through its lateral wall at anteromedial, paramedial, and Parkinson triangles. In the early 1980s after the combined orbitomalar osteotomy # !# ? al.,19 Hakuba et al.14 described the combined orbitozygo-matic infratemporal epidural and subdural approach for le-sions in the cavernous sinus, which were accessed through the lateral and superior wall, respectively. An anterior transpetrosal osteotomy could also be done through this approach to obtain access to the posterior fossa. The ap-proach provided the shortest possible distance and maxi-mum inferior-to-superior angle with minimal brain retrac-tion. Pieper and Al-Mefty22 and described the technique used today, while others have @6,12 Fujitsu and Kuwabara11 and Al-Mefty and Anand2 pro-posed zygomatic approaches that incorporated some other differences. These approaches were intended to be the FIG. 10. Axial (left) and coronal (right) MR images demonstrating an enhancing lesion of the right cavernous sinus with optic canal involvement. FIG. 11. Postoperative axial (left) and coronal (right) CT scans showing the extent of bone removal. T. Altay, B. C. K. Patel, and W. T. Couldwell 762 J Neurosurg / Volume 116 / April 2012 lowest possible supratentorial route to the cavernous sinus and the interpeduncular cistern. The approach described by Fujitsu and Kuwabara11 required detachment of the en-tire lateral orbital rim and the zygomatic arch, and entry to the cavernous sinus was achieved through the Parkin-son triangle. The zygomatic approach that Al-Mefty and Anand2 described differed in that, after detachment of the zygomatic arch, the coronoid process of the mandible was sectioned and the temporalis muscle was elevated to ex-pose the lower anterior temporal bone to gain access to the cavernous sinus and infratemporal fossa. Perneczky et al.21 and Knosp et al.15 favored a small preauricular subtemporal approach to reach the cavernous sinus from various angles through the Parkinson triangle at its lateral wall. They tai-lored the subtemporal approach depending on the local-ization of the lesion using either an anterior subtemporal craniotomy with orbitopterional extension or a mid- to pos-terior subtemporal craniotomy. They obtained similar out-comes by using their approach, as did the authors of studies describing large-scale approaches but with less morbidity. Sekhar et al.23 used a subtemporal-preauricular infratem-poral fossa approach for large lateral and posterior cranial base tumors invading multiple middle and posterior fossa as well as infratemporal compartments. In 1997, Couldwell et al.5 described the use of a transmaxillary route to the cavernous sinus, traversing the pterygopalatine fossa and exposing the cavernous sinus by enlarging the foramen ro-tundum. Each of the aforementioned approaches has had a sig- cavernous sinus lesions. Most of them are based on a large !"#" @ drilling, wide intra- and/or extradural exposure, manipula-tion of critical neurovascular structures, and detachment of temporal muscle to varying degrees. Some of these are also longer operation times. Considering all these factors, we considered a less invasive approach for lesions primarily or secondarily involving the cavernous sinus. The aim was to take advantage of the easy and quick accessibility to the cavernous sinus through the removal of the lateral orbital rim and wall as far back as the neural elements in the su- The lateral orbitotomy by removing the lateral orbital ## UUXYZ16 to remove an in-traorbital tumor. Later, Dollinger10 used this approach for the treatment of exophthalmos. Andaluz et al.3 described removal of the superolateral wall of the orbit to access the anterior cranial fossa with inclusion of a mini-supraorbital craniotomy. Recently, Mariniello et al.17 reported a series of 18 patients harboring lateral sphenoid wing meningio-mas in whom the authors removed the lateral orbital wall including the lateral orbital rim and temporal portion of the sphenoid wing. The common features of the tumors in their series were variable involvement of the sphenoid wing, temporal fossa, and superolateral orbital cavity with-out extension to the anterior clinoid process and superior %# any study reporting access to the cavernous sinus through the removal of the lateral orbital wall without a formal cra-niotomy. The initial exposure obtained by the translateral or-bital wall approach we describe was the anteromedial face of the temporal pole. This precluded the necessity of brain & # angle of the approach, which enabled easy detachment of the temporal dura from the lateral wall of the cavernous si- # & [$ anterior two-thirds of the lateral cavernous sinus as well as part of V3 were readily accessible. Extradural removal of the anterior clinoid process by drilling enhanced access to the cavernous sinus through the entire course of its supe-rior wall. This also facilitated more posterior exposure as far back as the gasserian ganglion at a wider craniocaudal angle and provided an immediate proximal control of the ICA at its clinoid segment. By further drilling superiorly in the lower aspect of the sphenoid ridge and inferiorly in the remaining lateral orbital wall toward the inferior or- " \ " respectively, were within reach. Our initial approach with removal of only the lateral orbital wall was limited by the edge of the sphenoid wing laterally; this prevented us from entirely accessing V3, the foramina ovale and spinosum, the GSPN, the petrous carotid artery, and the middle and lateral temporal fos-sae. The extended version of our approach expanded the surgical borders to include these structures. We were also able to reach the posterior fossa after dissecting the middle fossa dura from the petrous ridge. Several techniques have been described to achieve optimal cosmesis after transorbital approaches. Stallard25 YZ"16 making the skin incision in the eyebrow line. Pelton and Patel20 described the superomedial lid crease approach to the medial intraconal space, and Andaluz et al.3 and Mariniello et al.17 used a similar technique with successful outcomes. In our study, we decided to use a lat-eral canthotomy, another cosmetically appealing technique that involves collaboration with the ocular plastic surgery department. This technique was simply based on the uti-lization of a natural skin crease in the lateral canthus at a length of 2 cm, followed by a subcuticular skin closure, which provided optimal cosmesis. There are several advantages of the approach de-scribed here over the previously described approaches. Principally, there is no requirement for any kind of brain retraction during the procedure. Another advantage is that it is performed through a small skin incision without any of the formal conventional craniotomies, thus avoiding wide exposure of the cerebrum and the associated complications of that surgical technique. The temporalis muscle inser-tion is left intact, and thus the risk of atrophy is eliminated. The frontalis branch of the facial nerve as well is left intact without retraction, as may occur in a standard frontotem-poral approach. The translateral orbital wall approach uses a quick and safe drilling of the lateral orbital wall with an immediate exposure at the anterior cavernous sinus, which provides a shorter operative time. The disadvantages of this approach include the unfa-miliar anatomy of the sphenocavernous region from below at a translateral orbital angle of view. Practice in the ca- J Neurosurg / Volume 116 / April 2012 Lateral orbital wall approach to the cavernous sinus 763 daver laboratory is mandatory to develop familiarity with the approach. In addition, excessive globe retraction or the use of improper equipment for retraction could cause po-tential injury to the periorbita or globe. Furthermore, al-though this step appeared to be easy, removal of the ante-rior clinoid process requires utmost care, as it does in other conventional approaches, because of its proximity to vital neural and vascular structures. In this study, we have described a novel approach to the cavernous sinus. Based on this initial cadaveric study, it appears that this approach may be applicable to a variety of lesions, especially tumors, in or around the cavernous si- ] resected by this technique in its simple form, whereas the extended version is suitable for lesions that extend laterally or posterolaterally in the middle fossa. The authors report no conflict of interest concerning the mate-rials or methods used in this study or the findings specified in this paper. Author contributions to the study and manuscript preparation include the following. Conception and design: Couldwell, Altay. Acquisition of data: Altay. Analysis and interpretation of data: Altay. Drafting the article: Altay. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Couldwell. Administrative/technical/material support: Couldwell. The authors would like to acknowledge Professor M. Gazi <> Kristin Kraus, M.S., is thanked for her superb editorial assistance. 1. Al-Mefty O: Supraorbital-pterional approach to skull base le-sions. ! "#$474-477, 1987 2. Al-Mefty O, Anand VK: Zygomatic approach to skull-base lesions. J Neurosurg 73:668-673, 1990 3. 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Fujitsu K, Kuwabara T: Zygomatic approach for lesions in the interpeduncular cistern. *! ,"$340-343, 1985 $ *Y`"]#Y"}#`/`" ~{ orbitozygomatic craniotomy for craniopharyngioma resection in children. Clinical article. *! 4 '$345-352, 2009 13. Hakuba A, Nishimura S, Shirakata S, Tsukamoto M: [Surgical approaches to the cavernous sinus. Report of 19 cases.] ! . 58 ;""$295-308, 1982 (Jpn) 14. Hakuba A, Tanaka K, Suzuki T, Nishimura S: A combined orbi-tozygomatic infratemporal epidural and subdural approach for lesions involving the entire cavernous sinus. J Neurosurg 71: 699-704, 1989 15. Knosp E, Perneczky A, Koos WT, Fries G, Matula C: Menin-giomas of the space of the cavernous sinus. ! )&$ 434-444, 1996 | YZ~{ ? / Dermoidzysten der Orbita. < = '$149-163, 1889 17. Mariniello G, Maiuri F, de Divitiis E, Bonavolontà G, Tranfa F, Iuliano A, et al: Lateral orbitotomy for removal of sphenoid wing meningiomas invading the orbit. ! ,, 5, >% ;$287-292, 2010 U ?\}"~~{ # - sating exophthalmus: a fortuitous cure. *>,$191-195, 1963 19. Pellerin P, Lesoin F, Dhellemmes P, Donazzan M, Jomin M: Usefulness of the orbitofrontomalar approach associated with bone reconstruction for frontotemporosphenoid meningiomas. ! #+$715-718, 1984 20. Pelton RW, Patel BC: Superomedial lid crease approach to the medial intraconal space: a new technique for access to the op-tic nerve and central space. %4 >#2$ 241-253, 2001 21. Perneczky A, Knosp E, Matula C: Cavernous sinus surgery. Ap-proach through the lateral wall. ! 5/ ;?"$ 76-82, 1988 22. Pieper DR, Al-Mefty O: Cranio-orbito-zygomatic approach. %8! "$2-9, 1999 23. Sekhar LN, Schramm VL Jr, Jones NF: Subtemporal-preau-ricular infratemporal fossa approach to large lateral and pos-terior cranial base neoplasms. J Neurosurg 67:488-499, 1987 24. Sekhar LN, Sen CN, Jho HD, Janecka IP: Surgical treatment of intracavernous neoplasms: a four-year experience. Neuro- "'$18-30, 1989 25. Stallard HB: A plea for lateral orbitotomy: with certain modi- <*% ''$718-723, 1960 $| <>*{. @A A<$. - !>8 BNew York: Thieme, 1996 $ <>*" `"]~"`YY"'~" RD: Microsurgical pterional approach to aneurysms of the bas-ilar bifurcation. >! ,$83-91, 1976 $U <>*" `]{& - nial aneurysms. >! )$7-14, 1975 Manuscript submitted July 21, 2011. Accepted December 1, 2011. Please include this information when citing this paper: published online January 13, 2012; DOI: 10.3171/2011.12.JNS111251. Supplemental online information: Video: http://mfile.akamai.com/21490/wmv/digitalwbc.download. akamai.com/21492/wm.digitalsource-na-regional/JNS11-1251_ video_NEW.asx (Media Player). http://mfile.akamai.com/21488/mov/digitalwbc.download. akamai.com/21492/qt.digitalsource-global/JNS11-1251_video_ NEW.mov (Quicktime). Address correspondence to: William T. Couldwell, M.D., Ph.D., Department of Neurosurgery, University of Utah, 175 North Medical Drive East, Salt Lake City, Utah 84132. email: [e-mail]. edu.