Modified osteoplastic orbitozygomatic craniotomy

Technical note

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✓ The authors report on a surgical technique involving a one-piece osteoplastic bone flap, which incorporates the frontal, temporal, and lateral portions of the orbital rim as a technically simpler alternative to the standard orbitozygomatic (OZ) craniotomy. The orbital rim component extends just laterally from the supraorbital foramen/notch to the frontozygomatic suture. This craniotomy obviates the need for removing the zygoma and has evolved from the authors' experience in more than 200 patients with a variety of pathological lesions, both vascular and tumorous.

The osteoplastic aspect of this technique was initially evaluated in 14 cadaveric sites in seven heads dissected prior to implementing this procedure clinically. The osteoplastic bone flap minimally obstructs the surgical view and provides all the advantages of a standard OZ craniotomy. Temporalis muscle atrophy leading to temporal hollowing is avoided, a bone union to the calvaria is improved, and the possibility of bone infection is decreased. The osteoplastic component of the technique adds to the improved long-term cosmesis and warrants active consideration in the art of neurosurgery.

Abstract

✓ The authors report on a surgical technique involving a one-piece osteoplastic bone flap, which incorporates the frontal, temporal, and lateral portions of the orbital rim as a technically simpler alternative to the standard orbitozygomatic (OZ) craniotomy. The orbital rim component extends just laterally from the supraorbital foramen/notch to the frontozygomatic suture. This craniotomy obviates the need for removing the zygoma and has evolved from the authors' experience in more than 200 patients with a variety of pathological lesions, both vascular and tumorous.

The osteoplastic aspect of this technique was initially evaluated in 14 cadaveric sites in seven heads dissected prior to implementing this procedure clinically. The osteoplastic bone flap minimally obstructs the surgical view and provides all the advantages of a standard OZ craniotomy. Temporalis muscle atrophy leading to temporal hollowing is avoided, a bone union to the calvaria is improved, and the possibility of bone infection is decreased. The osteoplastic component of the technique adds to the improved long-term cosmesis and warrants active consideration in the art of neurosurgery.

The standard frontotemporal OZ craniotomy is a commonly adopted avenue of access to lesions—whether vascular or tumorous—involving the vicinity of the orbital apex, paraclinoid and parasellar regions, cavernous sinus, and anterior and middle fossa floor. Little attention is drawn to the necessity of such an extensive cranial base approach. Furthermore, the cosmesis of such interventions, principally temporal muscle atrophy with asymmetry and slumping resulting in temporal fossa depression, is seldom addressed. In addition, devascularization of the free bone flap together with antecedent atrophy and suboptimal healing along the craniotomy line combined with a heightened risk of infection are not mentioned.

In this report, the technical details of a simple osteoplastic modified OZ craniotomy without removal of the zygoma to achieve adequate access are described. The osteoplastic component provides a subperiosteal tunnel beneath the temporalis muscle from the root of the zygoma to the anatomical keyhole while maintaining the attachment between the temporalis muscle belly and the temporal squama. This technique involves a one-piece osteoplastic bone flap that incorporates the frontal, temporal, and lateral portions of the orbital rim as a technically simpler alternative. The orbital rim component extends from just lateral to the supraorbital foramen/notch to the frontozygomatic suture. The osteoplastic bone flap minimally obstructs the surgical view and provides the advantages of the standard OZ exposure. Use of this technique avoids temporal hollowing from temporalis muscle atrophy or slumping while maintaining vascularization of the one-piece bone flap together with a decreased incidence of bone infection, and improves bone union with the calvaria.

The osteoplastic modified OZ craniotomy is easy to perform and offers extensive exposure of the skull base. Furthermore, the vascularized bone flap can be easily secured to the calvaria with anatomical reapproximation of the orbital rim and offers excellent long-term functional and cosmetic results.

Surgical Technique
Patient Positioning

The patient is placed supine with a shoulder roll under the ipsilateral scapula. The head of the bed is raised to keep the patient's head 15° above the heart to facilitate CSF drainage. The patient's neck is extended to angle the head backward so that the frontal lobe will fall away from the orbital roof. The degree of contralateral head rotation (15–45°) is dictated by the location of the lesion. The patient's head is secured in a Mayfield three-pin headholder, and the headholder pins are kept well posterior to the planned incision site.

Skin Flap

An intravenous antibiotic agent is administered approximately 60 minutes prior to skin incision. Hair along the incision line is neither shaved nor cropped, although it is groomed away from the planned incision line and stapled to the scalp. A curvilinear skin incision is begun 1 cm anterior to the tragus at the level of the zygoma and behind the STA, because this artery is located anatomically posterior to the frontotemporal branch of the facial nerve. The incision is maintained behind the hairline for the entire course and ends contralaterally at the midpupillary line or the superior temporal line. To avoid the risk of injury to the superficially and anteriorly placed STA, the initial part of the incision should remain superficial.

The scalp is elevated in two layers while preserving a frontal vascularized pericranial flap. Harvesting a pericranial flap can facilitate obliteration of the frontal sinus and assist in dural repairs 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. Initially, the scalp flap is dissected in the subgaleal plane with the pericranium remaining on the underlying frontal bones. The scalp flap overlying the temporalis fascia is exposed in the manner described by Yaşargil and colleagues18 to a point within 4 cm of the orbital rim and is followed by an interfascial fat pad dissection to protect the frontotemporal branch of the facial nerve from damage. This nerve crosses the zygomatic arch approximately 2 cm anterior to the tragus and within 1 cm or less of the frontal branch of the STA; therefore, this artery can be used as a landmark to guide subfascial dissection. 5 The scalp flap is reflected anteriorly over the orbit to palpate the superior and lateral aspects of the supraorbital rim under the pericranium.

The largest area of pericranium exposed by reflecting the skin flap is dissected carefully from the calvaria and reflected anteriorly as a separate flap along the ipsilateral superior temporal line by using a periosteal dissector. When dissecting the pericranium from the supraorbital rim, the supraorbital foramen with its nerve and artery is typically encountered along the medial one third of the superior orbital rim. The supraorbital foramen is frequently incomplete anteriorly and therefore referred to as a notch, where the neurovascular contents can be dissected freely with the pericranium. If the supraorbital foramen is complete, then the supraorbital nerve and artery can be dissected by fracturing the foramen by using a small osteotome followed by retraction anteriorly with the pericranium. Along the supraorbital rim, the periorbita is contiguous with the pericranium. It is firmly attached at the supraorbital foramen/notch and the frontozygomatic suture but can be easily lifted between these two locations. With careful blunt dissection, the supraorbital and lateral orbital rims and the superior and lateral aspects of the orbital roof can be exposed while leaving the periorbita intact. The periorbita is separated for a distance of 2 to 3 cm posteriorly from the orbital rim. If the periorbita is violated, periorbital fat will interfere rapidly with exposure of the orbital rim. Bipolar coagulation of the cumbersome periorbital fat can minimize this problem following craniotomy.

The temporalis fascia and muscle are cut in the direction of the skin incision from the superior temporal line to the root of the zygoma. A periosteal instrument is used to dissect the temporalis muscle from the bone at the root of the zygoma for an area that would encompass a burr hole. This step is followed by blunt periosteal dissection of the temporalis muscle in a straight line from the root of the zygoma to the superior temporal line and to the location of the anatomical keyhole in a retrograde fashion as described by Oikawa and colleagues.14 The periosteum overlying the zygomatic process of the frontal bone and the frontozygomatic suture is undermined inferiorly to elevate the temporalis muscle to provide exposure of the keyhole. This procedure provides a subperiosteal tunnel beneath the temporalis muscle while maintaining the attachment of the belly of the temporalis muscle to the temporal squama and the superior temporal line (Fig. 1). Monopolar cauterization should not be used for dissection because it damages the subperiosteum.

Fig. 1.
Fig. 1.

Photograph demonstrating a left-sided cadaveric specimen following the harvest of the pericranial flap and the release of the supraorbital nerve from its notch. The temporalis fascia and muscle are cut in line with the incision and cleared off the bone at the root of the zygoma and the anatomical keyhole location by performing blunt periosteal dissection. A subperiosteal tunnel is created beneath the temporalis muscle from the root of the zygoma to the anatomical keyhole (white squares), burr holes (asterisks), and planned craniotomy (black dotted line).

Craniotomy Procedure

A skull model (Fig. 2) depicts the necessary bone cuts. Three burr holes are drilled: the first (#1 in Fig. 2A) is placed in the temporal bone above the root of the zygoma; the second (#2), just above the superior temporal line approximately 5 cm behind the keyhole; and the third (#3), at the anatomical keyhole. The third burr hole is then extended inferiorly in a golf club fashion to undercut the sphenoid ridge. A craniotome is used to connect the first burr hole to the second (Fig. 2A, step 1), and then the calvarial cut is advanced toward the orbital rim just lateral of the supraorbital foramen where its advancement will be halted by the roof of the orbit (Fig. 2A, step 2). Next, the craniotome is placed in the first burr hole and advanced toward the keyhole as limited by the temporalis muscle (Fig. 2A, step 3). This step is repeated in the opposite direction from the anatomical keyhole (which is shaped like a golf club) toward the first burr hole (Fig. 2A, step 4).

Fig. 2.
Fig. 2.

Photographs depicting skull model of a left-sided modified OZ craniotomy with numbered burr holes: #1, root of the zygoma; #2, superior temporal line; and #3, anatomical keyhole, which is extended inferiorly in the shape of a golf club to undercut the sphenoid ridge (A). Sequence of craniotomy steps indicated by the numbered arrows (1–4) and for the craniotome with a footplate attachment. Arrows 5 and 6 continue the sequence and represent bone cuts made using a high-speed drill. Step 7 indicates the use of an osteotome, if necessary, to complete the bone cut in the temporal squama. Step 8 involves cracking the thin orbital roof as the bone flap is elevated anteriorly (B). An osteotome can facilitate propagating a fracture line from burr hole #3 to the osteotomy at the orbital rim completed by Step 5.

A high-speed side-cutting drill bit is used to section the last uncut 1 cm of the orbital rim while the periorbita and globe are protected (Fig. 2A and B, step 5). The zygoma is cut lateral to the frontozygomatic suture to free the zygomatic process of the frontal bone, extending posteriorly toward the keyhole while the periorbita and globe are protected (Fig. 2A and B, step 6). If necessary, an osteotome can be used to propagate a fracture underneath the temporalis muscle to complete the cut between the anatomical keyhole (Fig. 2A, step 7) and the root of the zygoma. The bone flap is now attached to the calvaria via the thin orbital roof, which can be cracked.12 The cracking of the orbital roof can also be facilitated with the use of an osteotome and may be particularly useful when the frontal sinus extends laterally beyond the supraorbital foramen, lending to an intact posterior wall of the frontal sinus. The osteotome is placed in the anatomical keyhole, and a fracture line is propagated along the roof of the orbit to the previous osteotomy site located just lateral to the supraorbital rim (Fig. 2B, step 8). The osteoplastic bone flap with its attached temporal muscle is now reflected inferolaterally without compromising the operative field. Following the craniotomy, the sphenoid ridge is flattened and the bone encompassing the anterior aspect of the middle fossa is removed using rongeurs and drills equipped with cutting and diamond burrs, as dictated by the pathology at hand. When necessary the craniotomy of the temporal squama can be directed as far posteriorly as required from the root of the zygoma to gain access to the posterior aspect of the middle fossa.

The modified osteoplastic OZ craniotomy provides a simple but adequate cranial opening with minimal obstruction of the surgical view to expand the boundaries of skull base surgery to access lesions involving the parasellar region, the cavernous sinus, and the posterior petrous apex as previously described.6,8,10

Closing Procedure

On completion of the craniotomy, if the sphenoid or ethmoid sinuses are exposed because of additional cranial base surgery, these sinuses are packed with autologous adipose tissue and covered with a pericranial graft. The dura mater is closed or grafted in as watertight a manner as possible. If the frontal sinus has been exposed at the superior orbital rim, it is occluded with pieces of surgicel and covered with a vascularized pericranial graft sutured to the dura mater. When the inferiorly retracted osteoplastic bone flap is released, venous oozing will be identified from the temporalis muscle and the inner table as well as the edges of the vascularized bone flap on account of its diploic veins. This potential warrants meticulous hemostasis to avoid postoperative hematomas.

The osteoplastic bone flap is easily affixed to abut the calvaria by using titanium plates and screws to achieve anatomical reapproximation of the orbital rim. No additional reconstruction is required because this technique preserves the roof and the lateral walls of the orbit. Calcium phosphate bone cement (Norian; Synthes, Monument, CO) or, alternatively, methylmethacrylate is used to fill the bone defect at the anatomical keyhole location and optionally at the other calvarial gap and burr hole defect sites. The incision is closed in anatomical layers.

Results

The nonosteoplastic modified OZ craniotomy was initially performed using a nonosteoplastic bone flap for a spectrum of lesions in more than 200 cases during a 4-year period. Results of postoperative CT studies revealed anatomical reapproximation of the orbital rim and minimally absent bone following the procedure with reference to the orbital roof and the lateral orbital wall. This bone absence was located only over the fracture line situated 2 to 3 cm posterior to the orbital rim. This minimal lack of bone did not contribute to any perceptible clinical pulsatile exophthalmus in any of the patients who had undergone a 12-month follow up.

Periorbital swelling was noted and varied from patient to patient but was transient in nature and resolved within the first 72 hours. If periorbital ecchymosis was present, it resolved in 14 days. In our series, one patient experienced superior periorbital blistering following the procedure. This complication was attributed to an inappropriately short skin incision in an individual with a high receding hairline. Furthermore, the skin flap was excessively retracted to obtain exposure of the ipsilateral orbital rim. Such prolonged retraction was never witnessed when the skin incision was the appropriate length for comfortable skin retraction and easy exposure of the ipsilateral lateral orbital rim. Paresis of the frontotemporal branch of the facial nerve occurred in patients when the surgical technique described by Yaşargil18 was not followed by surgeons-in-training at our institution.

The simple modified OZ craniotomy provided an adequate cranial opening to expand the boundaries of cranial base surgery in a similar manner compared with the longerlasting standard OZ craniotomy. This fact was evidenced by our experience in performing the following: 1) extradural anterior clinoidectomy (40 cases of aneurysm lesions and 15 cases of selective tumoral lesions); 2) exposure of the entire cavernous sinus (15 cases); and 3) extradural removal of the petrous apex (12 cases for the Kawase triangle). Long-term follow up in all patients in the nonosteoplastic group revealed temporal fossa hollowing of various degrees, which was particularly pronounced in individuals with a thin temporalis muscle.

The osteoplastic technique described in this report has evolved from our experience in 20 patients with a follow up ranging from 12 to 18 months. Postoperative CT scans revealed the presence of a hematoma in 11 of 20 patients. An asymptomatic sliver of an epidural hematoma was present (10 cases) at the beginning of the series. When dural closure was not performed in a watertight manner, the epidural aspect was accompanied by a small subdural component (two cases). Only one patient was treated for the occurrence of a symptomatic hematoma caused by platelet dysfunction. All patients harboring a hematoma were followed more closely with no further consequences. In the initial osteoplastic case, dimpling of the skin was noticed at the site of the anatomical keyhole during the extended postoperative period following cessation of swelling. This consequence was attributed to the sinking of the temporalis muscle into the bone defect in the absence of temporalis muscle atrophy elsewhere. Improved cosmesis was achieved in future cases with the use of calcium phosphate bone cement (Norian) to plug the bone defect at the anatomical keyhole to avoid long-term skin dimpling with good success. The use of bone cement at the edges of the craniotomy and at the burr hole above the root of the zygoma was optional, and its absence did not detract from the overall cosmesis of the procedure. Results of long-term follow-up CT scanning studies (15 cases) revealed that the vascularized bone flap had facilitated bone union where the flap abutted the calvaria, which, we concluded, was indicative of improved healing. No patient suffered an infection of an osteoplastic bone flap, and in general patients were satisfied with their long-term functional and cosmetic outcomes.

Discussion

Significant attention in the neurosurgical literature has been directed to the use of the OZ craniotomy to facilitate exposure of the skull base since its original description by Hakuba and colleagues.9 Some investigators have asserted that the procedure's related incidence of morbidity and duration of operating time far outweigh the need for any additional exposure, whereas others continue to doubt whether additional exposure is gained at all.15 To settle this debate, we quantitatively performed a cadaveric study whose results demonstrated that the orbital osteotomy provided significant and consistent increases in surgical exposure, whereas the removal of the zygomatic arch produced less consistent gains.17 Furthermore, the adequacy of a lateral orbital rim osteotomy over that of an OZ craniotomy to gain a satisfactory surgical corridor was recently shown in seven patients with various pathologies located in the anterior, middle, and interpenduncular fossae.17

The modified osteoplastic OZ craniotomy reported here is a simpler, less complicated technique that can be performed quickly in a safer manner compared with the one-piece osteoplastic OZ model proposed by Hayashi and colleagues.11 First, the procedure does not require complete exposure of the zygoma, because it is cut just lateral to the frontozygomatic suture without removing the zygoma proper. This modification decreases the incidence of injury to the frontal branch of the facial nerve. Second, it does not involve the use of the inferior orbital fissure as part of the procedure. Therefore, the temporalis subperiosteal tunnel can be created with greater ease through retrograde dissection because it extends for a shorter distance from the root of the zygoma to the anatomical keyhole. The shorter subperiosteal tunnel provides less opportunity for damage to the temporalis muscle. Moreover, obviating the use of the inferior orbital fissure contributes to simplicity without compromising surgical freedom. If the basilar tip is more than 10 mm above the baseline connecting the anterior and posterior clinoid processes, however, then high-positioned basilar artery aneurysms can be more easily reached through the translocation of the zygomatic arch16 as well as the modified OZ craniotomy. Third, the orbital rim is routinely sectioned at a point just lateral to the supraorbital foramen/notch following the liberation of its contents as previously described to avoid forehead numbness. For medially projecting lesions, however, the craniotomy can be designed to encompass a greater portion of the medial orbital rim as required. Last, we, like others,4,7 have not encountered pulsatile enophthalmus during long-term follow up when the anterior roof and lateral wall of the orbit have been replaced.

One may wonder, why an osteoplastic bone flap? Temporalis muscle atrophy leading to temporal hollowing, temporalis muscle slumping, and possible painful mastication is a common sequela of frontotemporal craniotomy. We have noted that this result is attributed to the inappropriate elevation of the temporalis muscle off the temporal squama by the use of either the cautery instrument or an incorrect technique leading to denervation and devascularization. Oikawa and colleagues14 reported that the aforementioned consequence can be avoided by performing retrograde dissection, which preserves the deep temporal nerve and artery without damage to the subperiosteum of the temporalis muscle. Despite various temporal resuspension and fixation techniques,1–3,13,19 however, incorrect reattachment with undue muscle tension and muscle fiber damage also contribute to postoperative muscle contraction and/or slumping.

The answer to long-term cosmesis and good functional outcome is a one-piece osteoplastic bone flap. The most important functional and cosmetic advantage conferred is preservation of the temporalis muscle bulk in its normal anatomical form and location. Our procedure creates only minimal damage to the temporalis muscle bulk along the craniotome corridor and minimal, if any, opportunity for injury to the deep temporal nerve and artery given that the area of subperiosteal dissection is small. Furthermore, cosmesis is aided by the ease of reapproximating a single bone flap. Because of its osteoplastic nature, vascularization prevents atrophy, decreases the incidence of infection in the bone flap, and provides excellent bone union at its edges with the calvaria. In addition, the small gap in the posterior aspect of the bone flap and the calvaria as well as the inferior defect, which is dependent on the area of bone removed for access to the middle fossa, is covered by the temporalis muscle and does not contribute to any significant cosmetic issues. Finally, the osteoplastic flap has been criticized for its bulk, although it is minimal with the removal of the lateral orbital rim in comparison to an osteoplastic pterional craniotomy in our experience.

Diploic veins within the vascularized bone flap can be troublesome and contribute to postoperative epidural hematomas and to a subdural component as well if dural closure is incomplete. Therefore, the osteoplastic bone flap warrants meticulous hemostasis to avoid postoperative hematomas. It is essential to wax the bone channels on the inner table and the edges of the bone flap. More importantly, however, when the flap is not under the tension of retraction, the inner table should be examined for venous oozing from the small ostia of the inner table previously in continuum with the dura mater prior to craniotomy. This observation decreased the incidence of hematomas in the latter portion of our series. Note that even as we report observing asymptomatic hematomas, this consequence is not an uncommon finding on postoperative CT scans following any craniotomy, although it is less frequent compared with its occurrence following an osteoplastic craniotomy. Another alternative precaution involves placing a hemovac drain to decrease the incidence of postoperative epidural and subgaleal hematomas. Additional caution is exercised when the dura is not closed because the drain can siphon CSF inappropriately. We endeavor to achieve adequate hemostasis rather than rely on postoperative hemovac drains.

Conclusions

The modified OZ technique offers the following advantages: 1) technical simplicity; 2) shorter operating time; 3) decreased incidence of injury to the frontotemporal branch of the facial nerve; 4) excellent exposure of the skull base with a shorter and wider dissection distance; 5) minimal brain retraction; 6) easy replacement of a single bone flap; and 7) decreased postoperative discomfort compared with that following the standard OZ craniotomy. The osteoplastic component maintains the anatomy of the temporalis muscle for uncompromised function and cosmesis.

The described modifications to the OZ technique represent further refinements to the workhorse of cranial base surgery in terms of simplicity, whereas the osteoplastic component adds to the improved long-term cosmesis and art of neurosurgery.

Acknowledgments

We thank medical photographer Richard York for photographic assistance and Shirley McCartney, Ph.D., for assistance in figure preparation and editing.

References

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    Barone CMJimenez DFBoschert MT: Temporalis muscle resuspension using titanium miniplates and screws: technical note. Neurosurgery 48:4504512001Neurosurgery 48:

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    Bowles AP Jr: Reconstruction of the temporalis muscle for pterional and cranio-orbital craniotomies. Surg Neurol 52:5245291999Bowles AP Jr: Reconstruction of the temporalis muscle for pterional and cranio-orbital craniotomies. Surg Neurol 52:

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    Brunori ADiBenedetto AChiappetta F: Transosseous reconstruction of temporalis muscle for pterional craniotomy: technical note. Minim Invasive Neurosurg 40:22231997Minim Invasive Neurosurg 40:

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    Catalano PJSen C: Management of anterior ethmoid and frontal sinus tumors. Otolaryngol Clin North Am 28:115711741995Otolaryngol Clin North Am 28:

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    Coscarella EVishteh AGSpetzler RFSeoane EZabramski JM: Subfascial and submuscular methods of temporal muscle dissection and their relationship to the frontal branch of the facial nerve. Technical note. J Neurosurg 92:8778802000J Neurosurg 92:

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    Day JDGiannotta SLFukushima T: Extradural temporopolar approach to lesions of the upper basilar artery and infrachiasmatic region. J Neurosurg 81:2302351994J Neurosurg 81:

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    DeMonte FTabrizi PCulpepper SASuki DSoparker CNPatrinely JR: Ophthalmological outcome after orbital entry during anterior and anterolateral skull base surgery. J Neurosurg 97:8518562002J Neurosurg 97:

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    Dolenc VV: A combined epi- and subdural direct approach to carotid-ophthalmic artery aneurysms. J Neurosurg 62:6676721985Dolenc VV: A combined epi- and subdural direct approach to carotid-ophthalmic artery aneurysms. J Neurosurg 62:

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    Hakuba ALiu SNishimura S: The orbitozygomatic infratemporal approach: a new surgical technique. Surg Neurol 26:2712761986Surg Neurol 26:

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    Hakuba ATanaka KSuzuki TNishimura S: A combined orbitozygomatic infratemporal epidural and subdural approach for lesions involving the entire cavernous sinus. J Neurosurg 71:6997041989J Neurosurg 71:

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    Hayashi NHirashima YKurimoto MAsahi TTomita TEndo S: One-piece pedunculated frontotemporal orbitozygomatic craniotomy by creation of a subperiosteal tunnel beneath the temporal muscle: technical note. Neurosurgery 51:152015242002Neurosurgery 51:

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    Jane JAPark TSPobereskin LHWinn HRBulter AB: The supraorbital approach. Technical note. Neurosurgery 11:5375421982Neurosurgery 11:

  • 13.

    Miyazawa T: Less invasive reconstruction of the temporalis muscle for pterional craniotomy: modified procedures. Surg Neurol 50:3473511998Miyazawa T: Less invasive reconstruction of the temporalis muscle for pterional craniotomy: modified procedures. Surg Neurol 50:

  • 14.

    Oikawa SMizuno MMuraoka SKobayashi S: Retrograde dissection of the temporalis muscle preventing muscle atrophy for pterional craniotomy. Technical note. J Neurosurg 84:2972991996J Neurosurg 84:

  • 15.

    Ojemann RG: Skull-base surgery: a perspective. J Neurosurg 76:5695701992Ojemann RG: Skull-base surgery: a perspective. J Neurosurg 76:

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    Sano KShiokawa Y: The temporo-polar approach to basilar artery aneurysms with or without zygomatic arch translocation. Acta Neurochir 130:14191994Acta Neurochir 130:

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    Schwartz MSAnderson GJHorgan MAKellogg JXMcMenomey SODelashaw JB Jr: Quantification of increased exposure resulting from orbital rim and orbitozygomatic osteotomy via the frontotemporal transsylvian approach. J Neurosurg 91:102010261999J Neurosurg 91:

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    Yaşargil MGReichman MVKubik S: Preservation of the frontotemporal branch of the facial nerve using the interfascial temporalis flap for pterional craniotomy. Technical article. J Neurosurg 67:4634661987J Neurosurg 67:

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    Zager ELDelVecchio DABartlett SP: Temporal muscle microfixation in pterional craniotomies. Technical note. J Neurosurg 79:9469471993J Neurosurg 79:

Article Information

Address reprint requests to: Johnny B. Delashaw Jr., M.D., Department of Neurological Surgery, Oregon Health & Science University, 3181 Sam Jackson Park Road, Portland, Oregon 97239. email: delashaw@ohsu.edu.

© AANS, except where prohibited by US copyright law.

Headings

Figures

  • View in gallery

    Photograph demonstrating a left-sided cadaveric specimen following the harvest of the pericranial flap and the release of the supraorbital nerve from its notch. The temporalis fascia and muscle are cut in line with the incision and cleared off the bone at the root of the zygoma and the anatomical keyhole location by performing blunt periosteal dissection. A subperiosteal tunnel is created beneath the temporalis muscle from the root of the zygoma to the anatomical keyhole (white squares), burr holes (asterisks), and planned craniotomy (black dotted line).

  • View in gallery

    Photographs depicting skull model of a left-sided modified OZ craniotomy with numbered burr holes: #1, root of the zygoma; #2, superior temporal line; and #3, anatomical keyhole, which is extended inferiorly in the shape of a golf club to undercut the sphenoid ridge (A). Sequence of craniotomy steps indicated by the numbered arrows (1–4) and for the craniotome with a footplate attachment. Arrows 5 and 6 continue the sequence and represent bone cuts made using a high-speed drill. Step 7 indicates the use of an osteotome, if necessary, to complete the bone cut in the temporal squama. Step 8 involves cracking the thin orbital roof as the bone flap is elevated anteriorly (B). An osteotome can facilitate propagating a fracture line from burr hole #3 to the osteotomy at the orbital rim completed by Step 5.

References

1.

Barone CMJimenez DFBoschert MT: Temporalis muscle resuspension using titanium miniplates and screws: technical note. Neurosurgery 48:4504512001Neurosurgery 48:

2.

Bowles AP Jr: Reconstruction of the temporalis muscle for pterional and cranio-orbital craniotomies. Surg Neurol 52:5245291999Bowles AP Jr: Reconstruction of the temporalis muscle for pterional and cranio-orbital craniotomies. Surg Neurol 52:

3.

Brunori ADiBenedetto AChiappetta F: Transosseous reconstruction of temporalis muscle for pterional craniotomy: technical note. Minim Invasive Neurosurg 40:22231997Minim Invasive Neurosurg 40:

4.

Catalano PJSen C: Management of anterior ethmoid and frontal sinus tumors. Otolaryngol Clin North Am 28:115711741995Otolaryngol Clin North Am 28:

5.

Coscarella EVishteh AGSpetzler RFSeoane EZabramski JM: Subfascial and submuscular methods of temporal muscle dissection and their relationship to the frontal branch of the facial nerve. Technical note. J Neurosurg 92:8778802000J Neurosurg 92:

6.

Day JDGiannotta SLFukushima T: Extradural temporopolar approach to lesions of the upper basilar artery and infrachiasmatic region. J Neurosurg 81:2302351994J Neurosurg 81:

7.

DeMonte FTabrizi PCulpepper SASuki DSoparker CNPatrinely JR: Ophthalmological outcome after orbital entry during anterior and anterolateral skull base surgery. J Neurosurg 97:8518562002J Neurosurg 97:

8.

Dolenc VV: A combined epi- and subdural direct approach to carotid-ophthalmic artery aneurysms. J Neurosurg 62:6676721985Dolenc VV: A combined epi- and subdural direct approach to carotid-ophthalmic artery aneurysms. J Neurosurg 62:

9.

Hakuba ALiu SNishimura S: The orbitozygomatic infratemporal approach: a new surgical technique. Surg Neurol 26:2712761986Surg Neurol 26:

10.

Hakuba ATanaka KSuzuki TNishimura S: A combined orbitozygomatic infratemporal epidural and subdural approach for lesions involving the entire cavernous sinus. J Neurosurg 71:6997041989J Neurosurg 71:

11.

Hayashi NHirashima YKurimoto MAsahi TTomita TEndo S: One-piece pedunculated frontotemporal orbitozygomatic craniotomy by creation of a subperiosteal tunnel beneath the temporal muscle: technical note. Neurosurgery 51:152015242002Neurosurgery 51:

12.

Jane JAPark TSPobereskin LHWinn HRBulter AB: The supraorbital approach. Technical note. Neurosurgery 11:5375421982Neurosurgery 11:

13.

Miyazawa T: Less invasive reconstruction of the temporalis muscle for pterional craniotomy: modified procedures. Surg Neurol 50:3473511998Miyazawa T: Less invasive reconstruction of the temporalis muscle for pterional craniotomy: modified procedures. Surg Neurol 50:

14.

Oikawa SMizuno MMuraoka SKobayashi S: Retrograde dissection of the temporalis muscle preventing muscle atrophy for pterional craniotomy. Technical note. J Neurosurg 84:2972991996J Neurosurg 84:

15.

Ojemann RG: Skull-base surgery: a perspective. J Neurosurg 76:5695701992Ojemann RG: Skull-base surgery: a perspective. J Neurosurg 76:

16.

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