Craniopharyngiomas are benign tumors that arise fromembryonic squamous cells of the craniopharyngeal duct(Rathke pouch).6,29,38,39,58 The substantial variability in thelocation of these tumors is determined by embryologicalevents in the sellar–suprasellar region.5,44 Although cranio-pharyngiomas arise primarily in the sellar and suprasellarregions, they can appear anywhere along the developmen-tal path of the Rathke pouch.34 Despite their benign histo-pathological features, craniopharyngiomas are usually veryadherent to the pituitary stalk and may infiltrate the regionof the tuber cinereum and hypothalamus, rendering theircomplete resection hazardous.16 These tumors grow by ex-pansion, although small papillary projections and reactiveastrogliosis may falsely give the impression of tumor inva-sion. Craniopharyngiomas may cause compression on pa-rasellar structures such as the optic chiasm and nerves, thepituitary stalk and gland, the floor of the third ventricle, andthe cerebral vasculature of the circle of Willis, thereby pro-ducing symptoms of visual loss, hypopituitarism, or hydro-cephalus.16,57

The surgical management of craniopharyngioma re-mains a challenge to neurosurgeons. The role of completesurgical removal of these tumors is still somewhat contro-versial. Although some favor radical resection, others haveadvocated less aggressive strategies, such as stereotacticcyst aspiration, intracystic brachytherapy, and stereotacticradiosurgery. These strategies may be used in a multimodalfashion to provide tumor control in select cases; however,

this may not eliminate the tumor entirely. Hoffman, et al.,17

advocated total excision whenever possible and achievedgross-total resection in the majority of cases in their series.Yasargil, et al.,58 promoted the strategy of complete tumorremoval rather than risking repeated surgical proceduresand/or radiation therapy for tumor recurrences. Symon andSprich51 also argued that obtaining a radical resection of alltumor that was accessible and visible microsurgically wasbest achieved at the first operation. In the experience re-ported by Fahlbusch, et al.,14 total resection was attempted;however, subtotal or partial resection was performed ifintraoperative findings indicated a significant risk of injur-ing critical neurovascular structures with radical resection.We agree that complete microsurgical removal, when safe,is the treatment of choice that offers the best chance of cure.

With advances in microsurgical and skull base tech-niques, safe gross- or near-total excision of these tumorshas become possible in the majority of cases, and these pro-cedures are associated with low rates of morbidity and mor-tality.1,16,17,38,41 This treatment method has also been facilitat-ed with adequate hormone replacement therapy. Althoughcraniopharyngiomas are not strictly tumors of skull baseorigin, they are usually intimately involved with several ofits areas, which often necessitates a skull base approachwhen resecting them.34,52 In this review, we present the dif-ferent cranial base surgical strategies in the resection ofcraniopharyngiomas, and discuss their respective advan-tages and disadvantages and relative indications. Otherstrategies, such as stereotactic cyst aspiration, intracysticbrachytherapy, and stereotactic radiosurgery will not be dis-cussed.

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Cranial base strategies for resection of craniopharyngiomain children

JAMES K. LIU, M.D., CHAD D. COLE, M.D., M.SC., JOHN R. W. KESTLE, M.D.,DOUGLAS L. BROCKMEYER, M.D., AND MARION L. WALKER, M.D.

Department of Neurosurgery, University of Utah School of Medicine, Primary Children’s MedicalCenter, Salt Lake City, Utah

The optimal treatment of craniopharyngioma in children remains a challenge. The use of complete excision to min-imize recurrence continues to be controversial because of the risk of postoperative morbidity and death. Advances inskull base approaches, modern microsurgical techniques, neuroimaging, and hormone replacement therapy, however,have allowed safe gross- or near-total resection in the majority of cases. Total removal of these tumors, if possible,offers the best chance of cure for the patient. Although craniopharyngiomas are not strictly tumors of skull base ori-gin, their intimate relationship with the neurovascular structures of this region often requires a skull base approach tomaximize the surgical corridor and facilitate adequate microsurgical resection. In this review, the authors focus oncommonly used skull base approaches for the surgical management of craniopharyngioma. They discuss the relativeindications, advantages, disadvantages, and complications associated with each approach. Illustrative cases and intra-operative videos are presented.

KEY WORDS • craniopharyngioma • skull base surgery • surgical approach

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Abbreviations used in this paper: CT = computerized tomogra-phy; MR = magnetic resonance.

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PREOPERATIVE CONSIDERATIONS

Tumor Classification

The extent and location of the tumor must be clarifiedbefore choosing the appropriate approach. The variabilityin location of craniopharyngiomas with respect to their sur-rounding structures has resulted in numerous topographicalclassifications.7,8,17,26,43,47,48,58 Most of these classification sys-tems are based on a vertical projection of tumor growthwith respect to the sella turcica, the optic chiasm, and thefloor of the third ventricle.48 Hoffman, et al.,17 classifiedcraniopharyngiomas as intrasellar, prechiasmatic, and re-trochiasmatic. Samii and Samii44 divided these tumors intofive grades depending on vertical extension: Grade I (tu-mor is located purely in the intrasellar or infradiaphragmat-ic region); Grade II (tumor is localized in the cistern withor without an intrasellar component); Grade III (tumorextends into the lower half of the third ventricle); Grade IV(tumor expands to the upper half of the third ventricle); orGrade V (tumor dome reaches the septum pellucidum orextends into the lateral ventricles). These classification sys-tems have facilitated selection of various surgical ap-proaches based on tumor location.7 Nevertheless, they arejust approximations, and as a practical matter, it may not beeasy to classify an individual tumor absolutely according tothese groups, because tumor growth may arise from sever-al points along the hypophysial axis.27

Neuroimaging Studies

The neuroimaging modality of choice is MR imaging,because of its precise demonstration of the extent and loca-tion of the tumor as well as the lesion’s relationship toimportant surrounding neurovascular structures.7 It is im-portant to determine the extent of intrasellar or suprasellarinvolvement and whether the tumor is prechiasmatic orretrochiasmatic, and to identify the presence of intraven-tricular involvement and posterior fossa extension. The useof MR imaging is also helpful in determining solid and cys-tic components of the tumor. Recognizing the presence ofhydrocephalus is important for preoperative planning, be-cause some patients may require external ventricular drain-age before surgery. Although MR imaging offers detailedanatomical information, the presence of adhesions cannotbe ascertained by viewing these images and may only bedetected at the time of surgical exploration.58 The use ofMR angiography is helpful in demonstrating the course andrelationship of the cerebral vasculature. The vessels of thecircle of Willis may be displaced or sometimes engulfed bylarger tumors. The use of CT scanning is beneficial in dem-onstrating the extent of calcifications in the tumor and theosseous changes in the skull base.

Endocrinological Evaluation

The endocrine status of the patient must be evaluatedbefore surgery is performed for lesions near the hypothala-mic–hypophysial axis. Preoperative endocrine evaluationshould include measurement of growth hormone, insulin-like growth factor–I, serum prolactin, morning cortisol,thyroid-stimulating hormone, thyroxine, triiodothyronine,follicle-stimulating hormone, luteinizing hormone, testos-terone in males, and estradiol in females. Patients with aninadequate pituitary reserve are at risk for intraoperative or

postoperative hypopituitarism, which can be dangerous inthe perioperative period.

The two most important hormone axes are those relatedto cortisol and thyroid production. A thyroid function pro-file and a baseline cortisol level should be obtained preop-eratively in anticipation of intraoperative manipulation ofthe hypothalamic–hypophysial axis. The risk of hypocorti-solemia is controlled by the concomitant use of exogenousglucocorticoid agents. Preoperative recognition of hypo-thyroidism is also important because it can manifest acute-ly during the early postoperative period. Ideally, patientsshould be given oral hormone replacements approximately1 week before surgery to establish a euthyroid state. In ur-gent or emergency cases, intravenous hormone replace-ment may be undertaken. In children, short stature or re-tarded linear growth are sometimes present because ofgrowth hormone deficiency. In adolescents, delayed or ar-rested puberty may be observed. Mild hyperprolactinemiais usually a result of hypothalamic–hypophysial disconnec-tion, or the “stalk effect.” Diabetes insipidus and the syn-drome of inappropriate antidiuretic hormone secretion arealso seen in the pediatric population.52

Neuro-Ophthalmological Evaluation

Because visual disturbances frequently occur in patientsharboring craniopharyngiomas, a formal neuro-ophthal-mological examination is warranted preoperatively. Thisserves as a baseline for comparison of visual status aftersurgery. The examination should include both visual acuityand visual field testing. A funduscopic examination shouldalso be performed to look for papilledema and optic atro-phy. Clinical manifestations of visual compromise may in-clude decreased visual acuity, diplopia, blurred vision,bitemporal hemianopia, central scotomas, see-saw nystag-mus, and blindness.51,52

Choosing the Appropriate Surgical Approach

Many approaches have been promoted for craniopharyn-giomas. Choosing the appropriate skull base approach de-pends primarily on the location of the lesion. The approachmust provide exposure that creates the shortest distance tothe lesion, adequate visualization of the lesion, control ofcritical neurovascular structures, and minimal brain retrac-tion. A surgical strategy can be established using the MRimaging and CT findings. Additionally, the concepts ofkeyhole microneurosurgery should be applied by removingor mobilizing additional bone at the outer surface of theskull, such as the supraorbital bar or the zygoma, so that awider exposure at the surface of the skull will improveviewing trajectories and instrument maneuverability. A“minimally invasive approach” should translate as an ap-proach that provides maximal exposure and minimal dam-age to the neural structures rather than as simply a “smallcosmetic incision.”

SURGICAL APPROACHES

Although various skull base approaches have been de-scribed for the excision of craniopharyngiomas, these canbe simplified into the following: anterior midline (sub-frontal, transsphenoidal); anterolateral (pterional, orbitozy-gomatic); and intraventricular (transcallosal–transventricu-

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lar, transcortical–transventricular, translamina terminalis)approaches. Variations of each approach can be tailored tothe patient by modifying the degree of bone removal. Fur-thermore, approaches can also be used in combination forextensive lesions that cannot be adequately accessed via asingle approach.

Subfrontal–Translamina Terminalis Approach

Advantages and Disadvantages. The subfrontal approach,also referred to as the bifrontal transbasal approach, is aversatile procedure for removing craniopharyngiomas thatare strictly midline with extension along the anterior skullbase and suprasellar cistern (Fig. 1).10 This approach hasthe advantage of a straight frontal trajectory with good con-trol of both optic nerves and internal carotid arteries. It alsohas the advantage of constituting a direct approach throughthe lamina terminalis for access to the anterior third ventri-cle if there is intraventricular extension of the tumor.3,49

This approach also allows the prechiasmatic portion of thecraniopharyngioma to be dissected easily between the opticnerves. Furthermore, any retrochiasmatic portion of thetumor can be excised through the opticocarotid space andthe lamina terminalis.7 The disadvantages of this approachinclude potential violation of the frontal sinus and damageto the olfactory tracts. This procedure is usually not recom-mended in patients with a prefixed chiasm.

Description of Procedure. The patient is positioned supinewith the head elevated 30˚ to facilitate venous drainage(Fig. 1). The head is extended to help with frontal loberelaxation. Lumbar drainage may be used for additionalbrain relaxation. After a bicoronal incision is made, thescalp flap is reflected anteriorly, followed by a bifrontalcraniotomy. The inferior limit of the bone flap should be atthe level of the orbital roof to maximize surgical exposureand minimize brain retraction. Harvesting a vascularizedpericranial flap from the scalp for subsequent reconstruc-tion of the cranial base at the time of closure is an impor-tant step in this procedure. Access to the anterior skull baseis less difficult in children than in adults because its floor isshallow and relatively foreshortened and the frontal sinus-es are not fully developed in children. Therefore, we rarelyremove the supraorbital bar (extended subfrontal approach)in these cases. If, however, the frontal sinuses are violated,exenteration and cranialization of the frontal sinuses fol-lowed by plugging of the nasofrontal ducts with muscleand bone chips is performed. The dura mater is openedtransversely a few millimeters behind the supraorbital bar.The superior sagittal sinus is ligated anteriorly with a sutureand divided along the plane of the dural incision at theinsertion of the falx cerebri.

After adequate brain relaxation is obtained, the frontallobes are gently held by self-retaining retractors. Careshould be taken to avoid excessive brain retraction to pre-vent postoperative edema or ischemia.22 The olfactory tractsare freed from their arachnoid attachments. The right olfac-tory tract is divided behind the olfactory bulb, providingexposure of the optic nerves. The chiasmatic and inter-hemispheric cisterns are opened carefully to expose theoptic nerves and chiasm, the lamina terminalis, the anteriorcommunicating artery complex, and the internal carotidarteries. The optic nerves and chiasm must be carefully dis-sected from the capsule of the craniopharyngioma. Tumors

in the prechiasmatic, opticocarotid, and carotid–oculomotorcisterns are readily accessible via the subfrontal approach.Cystic lesions are initially decompressed by opening thecapsule. To prevent aseptic meningitis, care should be takento prevent dissemination of intracystic contents to the sub-arachnoid space. Additionally, occlusion of the cerebralaqueduct by keratin and cholesterol found within the cran-iopharyngioma may result in hydrocephalus.7,19 The capsuleis then carefully dissected away from adherent neurovascu-lar structures by using the microsurgical technique. Incom-plete removal of the capsule may result in tumor recurrence.

Tools. Removal of intrasellar tumor is possible but directvisualization into the sellar floor is limited. We use angledendoscopes or dental mirrors to inspect for residual tumorin the sella turcica. These tools are also useful for inspect-ing the undersurface of the optic nerves and chiasm. It maybe possible to identify and preserve the pituitary stalk in pa-tients with small suprasellar tumors, but this becomes moredifficult with large lesions and may not be feasible becauseof the potential for leaving residual tumor behind. Once theprechiasmatic and suprasellar portions of the tumor havebeen removed, direct access into the retrosellar and retro-clival spaces can be attained, if needed. Craniopharyn-giomas that extend into the posterior fossa can be removed(Fig. 1, Video 1).

Click here to view the video clip: Removal of an extensive

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Fig. 1. Preoperative CT (A and B) and MR images (C: T1-weighted post-Gd sagittal MR image) of an extensive cranio-pharyngioma in a 9-year-old boy who presented with headaches,growth retardation, bitemporal hemianopia, and bilateral papillede-ma. The tumor occupied the anterior skull base, the intrasellar andsuprasellar region, and the retrochiasmatic region and extendedinto the retroclival prepontine space. A subfrontal approach wasused to achieve a gross-total resection (D: postoperative T1-weight-ed post-Gd sagittal MR image).

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craniopharyngioma by using the subfrontal approach in thepatient whose tumor is depicted in Fig. 1.

For retrochiasmatic craniopharyngiomas that residewithin the third ventricle, a translamina terminalis ap-proach is used. The lamina terminalis is situated betweenthe optic tracts and extends from the anterior commissureto the posterior limit of the optic chiasm. This forms the in-ferior two thirds of the anterior wall of the third ventricle.To access the tumor within the third ventricle, an incisionin the lamina terminalis is made in the anteriormost part ofthe ventricle, immediately posterior to the chiasm. This in-cision is extended from one optic tract to the other whilestaying below the anterior communicating artery. After thelamina terminalis is opened, the tumor can be identifiedand carefully dissected away from structures of the anteri-or hypothalamus. Care must be taken to limit excessive re-traction and damage to perforating vessels originating fromthe anterior cerebral artery.39 This approach is useful if sig-nificant intraventricular extension is present.

Transsphenoidal and Extended TranssphenoidalApproaches

Advantages and Disadvantages. Transsphenoidal resectionis favored for craniopharyngiomas that occupy both sellarand suprasellar regions, especially if the sella turcica is en-larged.4,8,12,14,18,21,23,28,30,32,38 This approach is most appropriatefor intrasellar and subdiaphragmatic craniopharyngiomas.An intrasellar location with enlargement of the sella turcicaand a rounded suprasellar extension indicates a subdia-phragmatic craniopharyngioma.14 Suprasellar extensions oftumors may be readily removed with the transsphenoidalapproach, given that they are primarily cystic and not solid.Both solid and cystic tumors in the intrasellar portion can beremoved with the transsphenoidal approach.

If the tumor is purely suprasellar with a normal-sizedsella turcica, extended variations such as the transsellar–transdiaphragmatic approach or the transsphenoidal–transtuberculum approach can sometimes be used.12,21,23,28,

32,36 By changing the trajectory of the nasal speculum andremoving additional bone from the skull base, an extendedtranssphenoidal approach can allow additional exposuredespite the presence of a normal sella turcica. A transsel-lar–transdiaphragmatic method of approaching the su-prasellar cisterns may be used in the surgical removal ofcraniopharyngiomas.14,21,32 In the transsphenoidal–transtu-berculum approach, bone is removed from the sellar floor,tuberculum sellae, and posterior part of the planum sphe-noidale for access to the contents of the basal cisterns.14,21,

28,38 This approach provides direct access to supradiaphrag-matic craniopharyngiomas adjacent or anterior to the pitu-itary stalk, without resecting the pituitary gland.7,38 In thesecases, the additional bone exposure provides improved vis-ualization of the suprasellar portions of the tumor and re-duces the amount of blind curettage in this region. Cystictumors are particularly amenable to drainage and removalby this approach. Excellent results in craniopharyngiomasresected via the transsphenoidal route or an extended vari-ation have been reported by Laws and colleagues,21,32

Maira, et al.,38 and Couldwell, et al.12 The transsphenoidalapproach may not be suitable for cases in which there is sig-nificant lateral extension. In these cases, a frontotemporalor a combined approach may be necessary.

The transsphenoidal approach is more difficult in youngchildren who do not have a pneumatized sphenoid sinus. Inthese cases, access to the sella turcica requires additionaldrilling of the sphenoid bone with the aid of stereotactic CTguidance.20,42 In general, we prefer not to use the transsphe-noidal approach as the primary one if the sphenoid sinus isnot favorably pneumatized.

The transsphenoidal approach offers a midline exposure,allowing dissection in the space around the optic nerves,avoiding brain retraction and some of the other disadvan-tages of transcranial surgery.7,28 Only the propensity for CSFleakage was slightly increased for craniopharyngioma re-moval compared with other standard transsphenoidal pro-cedures.38 Additionally, the risk of visual injury was foundto be reduced when compared with craniotomies performedto treat similar lesions.18,32,58 Craniopharyngiomas involvingthe sella turcica are particularly amenable to the transsphe-noidal approach because tumors in this location are mostoften cystic or friable.18,30,38 Furthermore, craniopharyngio-mas located within this region do not infiltrate surroundingstructures, making tumor debulking and capsule dissectionfrom the optic chiasm, hypothalamus, and pituitary stalkpracticable.38 This regional characteristic is in stark contrastto those infundibular craniopharyngiomas that are more of-ten calcified and those intraventricular craniopharyngiomasthat are almost always solid.39,40

Description of Procedure. The patient is placed supine onthe operating table with the head elevated approximately15˚ on a horseshoe headrest. In the standard transsphenoid-al–transsellar approach, the patient’s face is placed parallelto the ceiling. For the extended transsphenoidal approach,the head is further extended to allow visualization of the an-terior skull base and suprasellar region. The sella turcicacan be exposed with either a sublabial or an endonasal ap-proach as described elsewhere.11,35,36 A bivalve speculum isplaced, the sphenoid sinus is opened using Kerrison ron-geurs, and all sphenoid mucosa is exenterated. The sellarfloor is then removed with Kerrison rongeurs to expose thesellar dura mater. For the extended transsphenoidal ap-proach, the bone of the tuberculum sellae is removed byfirst removing a small amount of bone over the anterior sel-lar wall to expose the anterior circular sinus and then ex-tending this bone removal rostrally by using microrongeurs.The planum sphenoidale can be removed more anteriorly toprovide additional exposure of the suprasellar region. Onemust remain cognizant of the position of the circular sinus,which demarcates the anterior extension of the sella turcica,the anterior communicating artery complex superiorly, theethmoid sinuses anteriorly, and the optic nerves superolat-erally. Once the bone of the tuberculum sellae has been re-moved, the dura mater anterior and inferior to the circularsinus is opened in the midline. The sinus is then coagulatedand transected to gain a direct view of the suprasellar cis-tern while preserving the pituitary gland in its position. Thisapproach enables an unencumbered view of the suprasellarcistern above the pituitary gland.

After tumor removal, the dural defect must be repairedcarefully with autologous fascia lata and fat. The fat isplaced in the bony opening of the skull base, followed byfascia lata to cover the dural defect. A piece of Marlex meshcan be used to repair the skull base defect. The repair is but-tressed in place and supported by packing the sphenoid si-nus region with fat. Closure of the mucosal incisions is per-

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formed in the usual fashion as described previously.35,36 Forlarge skull base defects, lumbar drainage is used for sever-al days postoperatively.

Even though the transsphenoidal route is useful for cra-niopharyngiomas occurring predominantly within the sellaturcica with or without marked suprasellar expansion, itsuse in association with a transcranial approach has someimportant advantages, especially if the tumor spreads farbeyond the sella.27 In this case, the transsphenoidal routemay be used before the intracranial approach,24 in combi-nation with it,25 or afterward. Some surgeons recommendan interval of 3 months between operations.24 If a transcra-nial route is considered necessary in conjunction with atranssphenoidal approach, the majority of tumors can be re-moved with a subfrontal or pterional approach.

Pterional Approach

Advantages and Disadvantages. The pterional (frontotem-poral) approach is the workhorse for the surgical treatmentof craniopharyngiomas involving primarily the suprasellarcistern.58 This approach provides the shortest distance to thesuprasellar region for a transcranial approach. This expo-sure is suitable for removing craniopharyngiomas involvingthe intrasellar, suprasellar, prechiasmatic, and retrochias-matic regions (Fig. 2). This is also the preferred method inpatients with a prefixed chiasm, because the tumor can beresected beneath the chiasm.

A disadvantage of the pterional approach is the limitedview of the contralateral opticocarotid triangle and the con-tralateral retrocarotid space.7 Additionally, when the lami-na terminalis is accessed through a pterional craniotomy,the oblique trajectory of this route makes it difficult to visu-alize the posterior part of the third ventricle, especially theipsilateral lateral wall of the hypothalamus.5 This places thecolumns of fornix, supraoptic nuclei, organ vasculosum,and tuber cinereum at risk for retraction injury or perforat-ing vessel damage.13,39 If the surgeon anticipates that thecraniopharyngioma will be significantly extended posteri-orly within the third ventricle, a transcallosal– or transcorti-cal–transventricular approach allows better access.5

Description of Procedure. The patient is positioned supinewith the head rotated 30 to 45˚ to the left and the neckextended 15 to 20˚ so that the malar eminence is at thehighest point. This maneuver allows the frontal lobe to fallaway from the skull base. Additional brain relaxation canbe achieved with a lumbar or external ventricular drain. Afrontotemporal incision is made beginning in front of theear at the level of the zygoma and extending toward themidline behind the hairline. The temporalis muscle can bemobilized as a myocutaneous flap or as separate layers byusing an interfascial or subfascial muscle dissection.9,59 It isimportant not to violate the frontalis branch of the facialnerve. In younger children, the temporalis muscle is oftennot bulky, so a myocutaneous flap is usually sufficient. Afrontotemporal bone flap is elevated and the lesser wing ofthe sphenoid is drilled down to optimize the most basal tra-jectory to the skull base. The bone flap can be extendedmore medially to provide a more subfrontal trajectory totumors extending between the optic nerves. The anteriorclinoid process is removed if access to the anterior caver-nous sinus or paraclinoid region is needed. The dura materis then opened with a C-shaped incision centered on the

sphenoid wing. Wide splitting of the sylvian fissure is per-formed and CSF is released from the cisterns, which expos-es the parachiasmal spaces.

Depending on the location and extension of the tumor, itsextirpation may be performed through the opticocarotid,carotid–oculomotor, and prechiasmatic spaces. Attention ispaid to avoid violating the perforating arteries situated inthe opticocarotid triangle. Exposure of the anteroinferiorthird ventricle can be performed by opening the lamina ter-minalis, as described earlier, for access to craniopharyn-giomas of the third ventricle.39 The craniopharyngioma canbe carefully dissected away from the anterolateral neuralstructures and walls of the third ventricle, with careful at-tention directed to preservation of the visual pathways andthe hypothalamic structures. Endoscopy and angled pitu-itary curettes may be used to remove the more posteriorlysituated tumor.7

Orbitozygomatic Approach

Advantages and Disadvantages. The orbitozygomatic ap-proach is essentially a pterional craniotomy with removal ofthe supraorbital rim, zygomatic arch, or both.33,60 The orbit-ozygomatic approach provides a wider exposure at the sur-face of the cranium to allow more freedom to maneuversurgical instruments, and it improves the angles of exposureof the posterior clinoid, basilar apex, and suprasellar re-gion.15 This approach is useful for resecting craniopharyn-giomas with significant suprasellar extension because itoffers an improved inferior-to-superior (“looking-up”) viewto the hypothalamic and suprasellar region (Fig. 3, Video2). Removal of the zygomatic arch allows more inferiormobilization of the temporalis muscle and reduces the mus-cle bulk that may otherwise obstruct visualization.

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Fig. 2. Preoperative CT (A) and MR images (B and C: sagittaland coronal T1-weighted post-Gd MR images) of an intrasellar andsuprasellar craniopharyngioma in a 2-year-old boy that was resect-ed using a pterional approach. The postoperative T1-weighted post-Gd sagittal MR image (D) demonstrates a gross-total resection.

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Click here to view the video clip: Removal of a suprasel-lar craniopharyngioma by using the modified orbitozygomaticapproach in the patient whose tumor is depicted in Fig. 3.

The orbitozygomatic craniotomy is also very effective inapproaching those craniopharyngiomas that have signifi-cant superior extension into the third ventricle. By remov-ing the orbital rim and lateral sphenoid region, the obstruct-ing bone that typically limits adequate exposure of thesuperior third ventricle through the lamina terminalis orunderneath the A1 portion of the anterior cerebral artery iscircumvented. In essence, the angle of exposure, based onthe fulcrum of the inferior frontal lobe, is significantly im-proved.45

Description of Procedure. The patient positioning and skinincision are similar to that of the pterional approachdescribed earlier. A subfascial dissection of the temporalismuscle is performed to expose the orbitozygomatic com-plex.9,60 This complex can be removed with the frontotem-poral bone flap as one piece or it can be removed after fash-ioning the bone flap as two pieces. Alternatively, a modifiedorbitozygomatic approach (removal of the supraorbital rimor zygomatic arch only) can be performed, depending onthe location of the pathological entity (Fig. 3, Video 2).33

Care should be taken not to violate the temporomandibularjoint during the zygomatic osteotomy. The remainder of thesurgical approach is similar to that of the pterional approachdescribed earlier.

Transcallosal–Transventricular Approach

Advantages and Disadvantages. The anterior transcallosalapproach provides direct access to the lateral ventricle andthe foramen of Monro with minimal retraction of thebrain.29,31,37,55 This approach provides good exposure of ex-tensive craniopharyngiomas that occupy the anterior thirdventricle and project into the lateral ventricle through theforamen of Monro. This foramen serves as a corridor intothe anterior and middle portions of the third ventricle, par-ticularly when the foramen is dilated by the tumor.50 Whenthe exposure through the foramen of Monro is limited, oth-er maneuvers, such as subchoroidal exposure,54 transcho-roidal exposure,56 or interforniceal exposure,2 are requiredto gain access to the third ventricle. This approach can beused in combination with a subfrontal or frontotemporalone (pterional or orbitozygomatic) for large suprasellar andintraventricular craniopharyngiomas (Fig. 4).4,37 The trans-callosal approach permits removal of the intraventricularportion of the tumor as the first stage. Subsequently, if thebasal portion of the tumor remains inaccessible, the sub-frontal or frontotemporal approach may be used to extir-pate the extraventricular part of the craniopharyngioma.27

The transcallosal approach offers the advantages of ashorter distance to the third ventricle than with the trans-cortical approach, greater flexibility to explore the entireanterior–posterior extent of the third ventricle without dis-ruption of hemispheral tissue, no cortical incision, and an

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Fig. 3. Preoperative CT (A) and MR images (B and C: sagittal and coronal T1-weighted post-Gd MR images) of a large craniopharyn-gioma in a 4-year-old girl that was resected using a modified orbitozygomatic approach. D and E: Intraoperative photographs demon-strating the one-piece modified orbitozygomatic approach with removal of the supraorbital rim. The bone flap was extended frontally to allowa combined subfrontal and frontotemporal trajectory. F: Postoperative T1-weighted post-Gd sagittal MR image demonstrating a gross-totalresection.

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unobstructed view to the depths of the anterior third ventri-cle.46 If the lateral ventricles are small, the transcallosal ap-proach is preferred over the transcortical one, because it isnot dependent on enlarged lateral ventricles for access. Thisapproach offers limited control of the suprasellar region.Other major risks include retraction injury to the cerebralhemispheres; venous infarction from injury to the veinsdraining into the superior sagittal sinus; injury to the peri-callosal arteries; injury to the fornix and anterior commis-sure; and injury to the septal, thalamostriate, and internalcerebral veins.7

Description of Procedure. The patient is placed supinewith the head tilted up 30˚. The use of MR stereotactic guid-ance is helpful in planning the craniotomy and callosal inci-sion. An incision is made at the level of the coronal suturecrossing the midline.7,27 This incision can be extended infe-riorly toward the zygoma if a combined approach is plan-ned. A small bilateral bone flap allows good visualizationof the interhemispheral space.7 The dura mater is openedwith a C-shaped incision and reflected medially over the su-perior sagittal sinus. The right cerebral hemisphere is gen-tly retracted laterally. Venous infarction from injury to thesuperficial bridging veins is prevented by using intermittentretraction of the cerebral hemispheres and minimizing co-agulation of the bridging veins. The corpus callosum isopened for approximately 15 to 20 mm, between the peri-callosal arteries. Once the lateral ventricle is entered, thefollowing anatomical landmarks should be identified to cal-culate the surgical orientation: the choroid plexus, foramenof Monro, septum pellucidum, and thalamostriate vein.

Access into the third ventricle may be achieved throughthe foramen of Monro; if additional exposure is needed, ei-ther the subchoroidal or the interforniceal approach can beused.2,7 The subchoroidal approach53,54 is performed by op-ening the choroidal fissure along the tenia choroidea andretracting the choroid plexus and body of the fornix medi-ally to expose the velum interpositum, which is then op-ened between the thalamus and the ipsilateral internal cere-bral vein. The disadvantages of this approach are the risk ofdamage to the thalamus, the thalamostriate vein, and thechoroidal arteries. The interforniceal approach2,53 is per-formed by entering the natural plane between the fornicesthat opens into the roof of the third ventricle. This interfor-niceal division must be made exactly in the midline. It isimportant not to make the incision beyond the region of theinterface between the column of the fornix and the anteriorcommissure. This approach has the risk of creating bilater-al forniceal injury and memory loss.

Transcortical–Transventricular Approach

Advantages and Disadvantages. The transcortical–trans-ventricular approach is an alternative access to third ven-tricular craniopharyngiomas. This approach is favored if thelateral ventricles are enlarged from hydrocephalus, becauseit provides the surgical corridor with minimal cortical re-traction. The advantages of transcortical–transventricularexposure are that there is less risk of compromising an es-sential draining vein going to the sagittal sinus and lesschance of injuring the pericallosal arteries.46 This approachrequires violation of the cortex, however, which increasesthe risk of postoperative seizures. Risk of injury to the for-nix, thalamus, and deep venous structures is still a consid-eration when accessing the third ventricle.

Description of Procedure. The positioning of the patient isthe same as in the transcallosal approach. The use of MRstereotactic guidance is helpful in planning the transcorticaltrajectory to the lateral ventricle. The approach is perform-ed on the nondominant side unless the tumor is located pri-marily in the contralateral lateral ventricle. Either a coronalor a horseshoe incision is made to expose the frontal regionanterior to the coronal suture. A rectangular bone flap is el-evated over the region of the planned corticectomy. Thedura mater is opened with a C-shaped incision and reflect-ed medially toward the midline. A cortical incision is madeparalleling the course of, and in the center of, the middlefrontal gyrus for approximately 3 to 4 cm.46 The white mat-ter is then dissected toward the lateral ventricle by usingblunt dissection with malleable retractors. The plane of dis-section is directed toward the foramen of Monro. Once thelateral ventricle is entered, self-retaining retractors areplaced to obtain the exposure. At this juncture, the opera-tion is similar to the transcallosal approach. Additional ex-posure of the third ventricle can be obtained using either thesubchoroidal or the interforniceal approach, as describedearlier.

CONCLUSIONS

Skull base and microsurgical techniques are an importantaddition to the armamentarium for the surgical manage-ment of craniopharyngioma in children. If feasible, gross-total resection offers the best chance of cure. The recur-

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Fig. 4. Preoperative T1-weighted post-Gd MR images (A: sagit-tal view; B: coronal view) of a giant craniopharyngioma in a14-year-old boy that extended from the sellar floor to the corpuscallosum. The tumor was resected using a combined approach(transcallosal–transventricular approach followed by an orbitozy-gomatic approach). Postoperative MR images (C: sagittal view; D:coronal view) demonstrate a gross-total resection.

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rence rate is dependent on the extent of resection, which isdependent on the location, consistency (solid or cystic), andsize of the tumor and its adhesiveness to critical neurovas-cular structures. Preoperative neuroimaging is important indetermining the location and extent of the tumor and toplan the optimal surgical approach. A combined approachmay be required to achieve total resection.

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Manuscript received May 10, 2005.Accepted in final form May 23, 2005.Address reprint requests to: Marion L. Walker, M.D., Department

of Neurosurgery, University of Utah, 30 North 1900 East, Suite 3B409,Salt Lake City, Utah 84132. email: marion.walker@hsc.utah.edu.

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