AUTHOR(S): Delashaw, Johnny B., Jr., M.D.; Tedeschi, Helder, M.D.; Rhoton, Albert L., M.D. Department of Neurological Surgery, University of Florida Health Center, Gainesville, Florida Neurosurgery 30; 954-956, 1992 ABSTRACT: The authors present a surgical approach that incorporates the frontal sinus and extends a supraorbital craniotomy to include the lateral orbital rim and zygoma. The craniotomy provides wide exposure of the anterior fossa, orbit, ipsilateral middle fossa, and cavernous sinus. The procedure can be performed easily, and the bone flaps can be secured rapidly back into the anatomical position at the time of closure. This modified supraorbital craniotomy is ideal for large benign lesions originating along the sphenoid wing or orbit that expand into the anterior fossa. KEY WORDS: Frontal sinus; Orbit; Skull base; Supraorbital craniotomy INTRODUCTION Sphenoid wing meningiomas have the capacity to invade the orbit, cavernous sinus, sella, and anterior fossa with expanding growth. The lesions can manifest clinically with visual disturbances, endocrine abnormalities, cerebrospinal fluid (CSF) leaks, or seizures. Although recent advances in surgical instrumentation have improved the neurosurgeon's ability to resect these lesions, it is becoming readily apparent that adequate bone resection is required to decrease surgical morbidity for the patient and improve exposure. Access to tumors involving the anterior fossa, orbit, and middle fossa can be accomplished by several different surgical approaches, including a pterional craniotomy, a pterional craniotomy with an orbitozygomatic osteotomy, and a frontotemporal craniotomy incorporating the supraorbital rim. In this presentation, we will show how the supraorbital craniotomy described by Jane et al. (2) in 1979 can be modified for wide exposure of the anterior fossa, orbit, middle fossa, and cavernous sinus. This frontotemporal craniotomy incorporates the supraorbital rim and zygoma into a single bone flap and takes advantage of the frontal sinus. The modified approach is easy to perform and offers extensive exposure of the skull base, and its bone segments can be secured easily back into position for an excellent cosmetic result DESCRIPTION Surgical positioning requires that the neck be extended with the head above the heart level. The head is then turned 15° toward the side contralateral
to the tumor and secured into position. A bicoronal incision is made beginning less than 1 cm anterior to the tragus at the level of the zygoma. The skin flap is dissected in the subgaleal plane with the pericranium remaining on the underlying frontal bones. This skin flap is reflected anteriorly exposing both supraorbital rims. The pericranium is dissected carefully and reflected anteriorly as a separate flap. This pericranial flap can be used to obliterate the frontal sinus and cover the floor of the anterior fossa to prevent CSF leaks. The pericranial flap is harvested more easily in this manner than by attempting to separate it from the skin flap at the end of the surgical procedure. When dissecting the pericranium anteriorly to the supraorbital rim, the supraorbital foramen with its nerve and artery is encountered. Preservation of the nerve and artery can be accomplished easily. Frequently, the foramen is incomplete anteriorly, and the nerve and artery are dissected freely with the pericranium. If the supraorbital foramen is complete, then the nerve and artery can be dissected free by breaking the encompassing bone around it with a small osteotome. The nerve and artery then can be reflected anteriorly with the pericranium. Along the supraorbital rim, the pericranium is contiguous with the periorbita. With careful dissection, the supraorbital rim and orbital roof can be exposed leaving both the pericranium and periorbita intact. If the periorbita is violated, fat will interfere rapidly with the exposure of the orbital rim. Bipolar coagulation of the cumbersome periorbital fat can minimize this problem. The superficial temporalis fascia is cut in the direction of the muscle fibers 2 to 3 cm posterior to the lateral orbital rim and zygoma. This fascia is reflected anteriorly to protect the frontalis branch of the facial nerve in a manner similar to that described by Yasargil et al. (4) (Fig. 1). Periosteal dissection is performed along the entire length of the zygoma. Using a sidecutting bit, the zygomatic arch is cut in two places to form a 3-cm isolated segment of bone (Fig. 1). The temporalis muscle is cut 1 cm below the superior temporal line, leaving a cuff of fascia on bone, and also is cut posteriorly in the direction of the muscle fibers. The temporalis muscle is separated from bone using periosteal dissection and is reflected downward with the separated zygoma segment. This separated zygoma segment maintains its attachment with the masseter muscle and also allows the temporalis muscle to be reflected easily downward. At the time of closure, the temporalis muscle is approximated with sutures to the fascial cuff, and the zygoma segment is secured with wire or microplates. Avoiding a midline burr hole can be accomplished by carefully dissecting the anterior wall of the frontal sinus away from the skull table. A template can be made from a skull film, and the contour of the sinus can be traced onto the exposed frontal area (Fig. 2). It is important preoperatively to obtain an anteroposterior skull film taken 6 feet from the patient to acquire 1:1 magnification of the frontal sinus. The anterior wall then can be removed using a sidecutting bit or sagittal saw (Fig. 3). Septa can be separated from the anterior wall with the aid of an
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Neurosurgery 1992-98 June 1992, Volume 30, Number 6 954 Modified Supraorbital Craniotomy: Technical Note Technical Note
DISCUSSION When attempting to resect a lesion along the skull base, the surgeon selects a surgical approach that will provide wide exposure with minimal brain retraction. The supraorbital approach described by Jane et al. (2) in 1982 is used frequently by many surgeons to expose aneurysms of the anterior communicating artery complex, tumors along the floor of the frontal fossa or sphenoid wing, and superior orbital lesions. We have modified the supraorbital approach to incorporate within the bone flap the temporal bone, zygoma, and lateral orbit. The surgeon can take advantage of the frontal sinus to provide additional exposure as has been described by Colohan et al. (1) in 1985 and Persing et al. (3) in 1990. This modified supraorbital craniotomy provides more exposure of the orbital contents and anterior fossa and allows access to the temporal lobe and cavernous sinus. With the additional removal of bone along the orbital roof and anterior clinoid, the approach offers a wide exposure of the anterior fossa, sella, and ipsilateral middle fossa. In children and adults with an absent frontal sinus, a midline frontal burr hole can be made to initiate this modified supraorbital craniotomy. The frontal burr hole can be covered with methylmethacrylate at the time of closure to prevent a midline depression. The modified supraorbital craniotomy is safe, offers rapid wide exposure, and can be secured readily back into the anatomical
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
osteotome. The mucosa of the frontal sinus is removed with a curette or coagulation. The posterior wall of the sinus is removed with a drill and rongeur. If the patient is fortunate to have a large frontal sinus, the access to the entire anterior fossa can be accomplished through this frontal sinus exposure. However, if the frontal sinus is small, the removal of the posterior wall provides access to the midline for safely performing a craniotomy that incorporates both frontal bones. At the time of closure, the anterior wall of the frontal sinus can be secured back into position with sutures without any evidence of a midline cosmetic deformity. Additional burr holes are placed at the ipsilateral keyhole and temporal region. The Gigli saw and its passer are directed in the epidural space from the frontal sinus through the keyhole burr hole. The saw is passed under the zygoma where the previous zygomatic osteotomy was made. The ipsilateral supraorbital rim, a portion of the orbital roof, and the contiguous portion of the zygoma then can be separated easily from the lateral orbit with the Gigli saw (Fig. 4). If the patient has a large frontal sinus, a pterional craniotomy from the frontal sinus to the temporal bone is made with the craniotome and the bone flap is reflected off the sphenoid wing (Figs. 5 and 6). A craniotomy incorporating both frontal bones and the ipsilateral temporal bone is made in patients with a small frontal sinus (Fig. 7). This bone flap also can be separated from the skull by reflecting it off the ipsilateral sphenoid wing. At the time of closure, the modified supraorbital bone flap can be placed rapidly back into position and secured to surrounding bone for an aesthetically pleasing result.
Figure 2. Radiographic template (T) was placed on the skull to trace the configuration of the anterior wall (A) of the frontal sinus (FS) (B). The temporalis muscle (TM) was reflected inferiorly below the cut edge of the zygoma (arrow). A fascial cuff (FC) remains on the skull for the reapproximation of the temporalis muscle at the time of closure.
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Figure 1. Right supraorbital rim (SOR) and right zygoma (Z) were exposed in a cadaver dissection via a bicoronal incision. Superficial fascia of the temporalis muscle was incised (arrows) and reflected anteriorly to protect the frontalis branch of the facial nerve. In addition, the zygoma was cut in two places.
Figure 4. Gigli saw (GS) with its passer (GSP) was used to cut the supraorbital rim, remaining zygoma, and lateral orbit (LO). The posterior wall of the frontal sinus was removed demonstrating the dura (D) of the anterior fossa.
Figure 5. Craniotome was used to complete the modified supraorbital craniotomy. In addition, bone along the posterior lateral orbit was removed with rongeurs. The craniotomy exposes the dura of the frontal lobe (FL), temporal pole (TP), and the periorbita of the orbit (O).
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Figure 3. The anterior wall of the frontal sinus (AWFS) was cut with a sidecutting bit.
Figure 7. Diagram illustrates the modified supraorbital craniotomy in a patient with a small frontal sinus. In addition to the removal of the anterior wall of the frontal sinus, a midline posterior frontal burr hole is placed for a large craniotomy made with the craniotome.
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Figure 6. Bone flap of the right modified supraorbital craniotomy demonstrates the keyhole burr hole (KH), temporalis fascial cuff (FC), lateral orbit (LO), zygoma (Z), and supraorbital rim (SOR).
to the tumor and secured into position. A bicoronal incision is made beginning less than 1 cm anterior to the tragus at the level of the zygoma. The skin flap is dissected in the subgaleal plane with the pericranium remaining on the underlying frontal bones. This skin flap is reflected anteriorly exposing both supraorbital rims. The pericranium is dissected carefully and reflected anteriorly as a separate flap. This pericranial flap can be used to obliterate the frontal sinus and cover the floor of the anterior fossa to prevent CSF leaks. The pericranial flap is harvested more easily in this manner than by attempting to separate it from the skin flap at the end of the surgical procedure. When dissecting the pericranium anteriorly to the supraorbital rim, the supraorbital foramen with its nerve and artery is encountered. Preservation of the nerve and artery can be accomplished easily. Frequently, the foramen is incomplete anteriorly, and the nerve and artery are dissected freely with the pericranium. If the supraorbital foramen is complete, then the nerve and artery can be dissected free by breaking the encompassing bone around it with a small osteotome. The nerve and artery then can be reflected anteriorly with the pericranium. Along the supraorbital rim, the pericranium is contiguous with the periorbita. With careful dissection, the supraorbital rim and orbital roof can be exposed leaving both the pericranium and periorbita intact. If the periorbita is violated, fat will interfere rapidly with the exposure of the orbital rim. Bipolar coagulation of the cumbersome periorbital fat can minimize this problem. The superficial temporalis fascia is cut in the direction of the muscle fibers 2 to 3 cm posterior to the lateral orbital rim and zygoma. This fascia is reflected anteriorly to protect the frontalis branch of the facial nerve in a manner similar to that described by Yasargil et al. (4) (Fig. 1). Periosteal dissection is performed along the entire length of the zygoma. Using a sidecutting bit, the zygomatic arch is cut in two places to form a 3-cm isolated segment of bone (Fig. 1). The temporalis muscle is cut 1 cm below the superior temporal line, leaving a cuff of fascia on bone, and also is cut posteriorly in the direction of the muscle fibers. The temporalis muscle is separated from bone using periosteal dissection and is reflected downward with the separated zygoma segment. This separated zygoma segment maintains its attachment with the masseter muscle and also allows the temporalis muscle to be reflected easily downward. At the time of closure, the temporalis muscle is approximated with sutures to the fascial cuff, and the zygoma segment is secured with wire or microplates. Avoiding a midline burr hole can be accomplished by carefully dissecting the anterior wall of the frontal sinus away from the skull table. A template can be made from a skull film, and the contour of the sinus can be traced onto the exposed frontal area (Fig. 2). It is important preoperatively to obtain an anteroposterior skull film taken 6 feet from the patient to acquire 1:1 magnification of the frontal sinus. The anterior wall then can be removed using a sidecutting bit or sagittal saw (Fig. 3). Septa can be separated from the anterior wall with the aid of an
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Neurosurgery 1992-98 June 1992, Volume 30, Number 6 954 Modified Supraorbital Craniotomy: Technical Note Technical Note
DISCUSSION When attempting to resect a lesion along the skull base, the surgeon selects a surgical approach that will provide wide exposure with minimal brain retraction. The supraorbital approach described by Jane et al. (2) in 1982 is used frequently by many surgeons to expose aneurysms of the anterior communicating artery complex, tumors along the floor of the frontal fossa or sphenoid wing, and superior orbital lesions. We have modified the supraorbital approach to incorporate within the bone flap the temporal bone, zygoma, and lateral orbit. The surgeon can take advantage of the frontal sinus to provide additional exposure as has been described by Colohan et al. (1) in 1985 and Persing et al. (3) in 1990. This modified supraorbital craniotomy provides more exposure of the orbital contents and anterior fossa and allows access to the temporal lobe and cavernous sinus. With the additional removal of bone along the orbital roof and anterior clinoid, the approach offers a wide exposure of the anterior fossa, sella, and ipsilateral middle fossa. In children and adults with an absent frontal sinus, a midline frontal burr hole can be made to initiate this modified supraorbital craniotomy. The frontal burr hole can be covered with methylmethacrylate at the time of closure to prevent a midline depression. The modified supraorbital craniotomy is safe, offers rapid wide exposure, and can be secured readily back into the anatomical
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
osteotome. The mucosa of the frontal sinus is removed with a curette or coagulation. The posterior wall of the sinus is removed with a drill and rongeur. If the patient is fortunate to have a large frontal sinus, the access to the entire anterior fossa can be accomplished through this frontal sinus exposure. However, if the frontal sinus is small, the removal of the posterior wall provides access to the midline for safely performing a craniotomy that incorporates both frontal bones. At the time of closure, the anterior wall of the frontal sinus can be secured back into position with sutures without any evidence of a midline cosmetic deformity. Additional burr holes are placed at the ipsilateral keyhole and temporal region. The Gigli saw and its passer are directed in the epidural space from the frontal sinus through the keyhole burr hole. The saw is passed under the zygoma where the previous zygomatic osteotomy was made. The ipsilateral supraorbital rim, a portion of the orbital roof, and the contiguous portion of the zygoma then can be separated easily from the lateral orbit with the Gigli saw (Fig. 4). If the patient has a large frontal sinus, a pterional craniotomy from the frontal sinus to the temporal bone is made with the craniotome and the bone flap is reflected off the sphenoid wing (Figs. 5 and 6). A craniotomy incorporating both frontal bones and the ipsilateral temporal bone is made in patients with a small frontal sinus (Fig. 7). This bone flap also can be separated from the skull by reflecting it off the ipsilateral sphenoid wing. At the time of closure, the modified supraorbital bone flap can be placed rapidly back into position and secured to surrounding bone for an aesthetically pleasing result.
Figure 2. Radiographic template (T) was placed on the skull to trace the configuration of the anterior wall (A) of the frontal sinus (FS) (B). The temporalis muscle (TM) was reflected inferiorly below the cut edge of the zygoma (arrow). A fascial cuff (FC) remains on the skull for the reapproximation of the temporalis muscle at the time of closure.
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Figure 1. Right supraorbital rim (SOR) and right zygoma (Z) were exposed in a cadaver dissection via a bicoronal incision. Superficial fascia of the temporalis muscle was incised (arrows) and reflected anteriorly to protect the frontalis branch of the facial nerve. In addition, the zygoma was cut in two places.
Figure 4. Gigli saw (GS) with its passer (GSP) was used to cut the supraorbital rim, remaining zygoma, and lateral orbit (LO). The posterior wall of the frontal sinus was removed demonstrating the dura (D) of the anterior fossa.
Figure 5. Craniotome was used to complete the modified supraorbital craniotomy. In addition, bone along the posterior lateral orbit was removed with rongeurs. The craniotomy exposes the dura of the frontal lobe (FL), temporal pole (TP), and the periorbita of the orbit (O).
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Figure 3. The anterior wall of the frontal sinus (AWFS) was cut with a sidecutting bit.
Figure 7. Diagram illustrates the modified supraorbital craniotomy in a patient with a small frontal sinus. In addition to the removal of the anterior wall of the frontal sinus, a midline posterior frontal burr hole is placed for a large craniotomy made with the craniotome.
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Figure 6. Bone flap of the right modified supraorbital craniotomy demonstrates the keyhole burr hole (KH), temporalis fascial cuff (FC), lateral orbit (LO), zygoma (Z), and supraorbital rim (SOR).
