Skull Base Institute Home Page
Skull Base Brain Tumor Research

Endoscopic transglabellar approach to the anterior fossa and paranasal sinuses
By Reza Jarrahy, M.D., Sung Tae Cha, M.D., George Berci, M.D., F.A.C.S., Hrayr K. Shahinian, M.D.


Historically, surgical management of tumors of the anterior cranial fossa with extension to the paranasal sinuses has been problematic. Wide exposure of these lesions has traditionally called for prolonged retraction of the frontal lobes or potentially disfiguring transfacial approaches, subjecting patients to undesirable neurological and cosmetic morbidity. With the introduction of progressively less invasive procedures, however, intracranial tumors with craniofacial involvement have become amenable to en bloc resection with a minimum of deleterious consequences. Increasing experience with endoscopy as an imaging modality in intracranial and extracranial surgery has led to the adaptation of endoscopic techniques to this setting. We have used an entirely endoscopic transglabellar approach to the anterior fossa to resect suprasellar tumors in two patients. The use of endoscopy allowed thorough visualization of all critical structures at the paramedian skull base without the need for a bicoronal scalp flap, bifrontal osteotomies, or brain retraction. Both lesions were resected in their entirety with no perioperative complications and with acceptable cosmetic results. These cases demonstrate how the application of endoscopy to surgery of the anterior skull base and craniofacial skeleton can eliminate the need for excessively invasive techniques without compromising surgical success.

endoscopy, transglabellar surgery, transcranial surgery, craniofacial surgery, sinus surgery Introduction

Once thought to be "inoperable" due to the challenges associated with surgical access, tumors of the anterior cranial fossa, orbits, and paranasal sinuses with both craniofacial and intracranial components can now be resected en bloc.1-4 Pathologically, these lesions include adenoid cystic tumors, pituitary adenomas, craniopharyngiomas, chordomas, chondrosarcomas, meningiomas, and esthesioneuroblastomas. Complete resection of these tumors has been made possible by the introduction of transcranial and transfacial approaches that offer access to the involved cavities. Wide exposure, however, often comes at the expense of a significant degree of brain retraction and facial dissection, which in turn may result in undesirable perioperative morbidity.

To minimize the deleterious effects of frontal lobe retraction and to avoid the use of facial incisions, approaches to these tumors have become progressively less invasive. Strategic modeling of osteotomies eliminates the need for excessive surgical manipulation without sacrificing exposure or outcome. Recently a transglabellar approach to the anterior fossa via a diminutive frontal osteotomy has been reported.5 This technique obviates the need for a bicoronal scalp flap or an extensive bifrontal craniotomy without diminishing visualization of the paramedian skull base.

The use of endoscopy as the sole imaging modality in this setting has not been described, yet it is ideally suited to exploration of the anterior fossa and surrounding sinuses. The adaptation of rigid endoscopy to the transglabellar approach broadens the available surgical exposure without the introduction of additional dissection or retraction. Endoscopes of varying angles of view provide a panoramic perspective of the relevant surgical anatomy and allow for thorough evaluation of the extent of intracranial and extracranial disease. The maneuverability of the endoscope allows the surgeon to position it directly at the level of dissection, effectively reducing the viewing and operating distances. Endoscopic imaging thereby facilitates complete tumor resection via a minimally invasive technique.

Surgical technique

The patient is placed supine on the operating room table and the head of the bed is slightly raised. Following the induction of general anesthesia, the patient's neck is extended approximately 15° and the head is fixed in place using a three-pin clamp. Thus positioned, the frontal lobes will fall away from the floor of the anterior once cerebrospinal fluid (csf) is drained. The frontal and nasal areas are cleansed with an aqueous antiseptic solution and then draped.

The base of a pneumatically powered endoscope holding arm (Mitaka Kohki Co., Tokyo) is fastened to the operating room table opposite the surgeon; the arm extends over the patient. A 4.0 mm 0° rigid endoscope (Karl Storz of America, Culver City, CA, USA) is attached to the holding arm.

A 4-5 cm incision is made between the medial ends of the eyebrows, crossing the nasion in a skin crease. The skin flap is developed in a subcutaneous plane and retracted superiorly. The glabellar periosteum is elevated separately and retracted inferiorly for further use as a pedicled pericranial flap in reconstruction of the skull base. A small burr hole is placed in the frontal bone and the outer table of the frontal sinus is osteotomized. Once the sinus cavity is exposed, its mucosa is resected and the nasofrontal ducts are obliterated. A burr hole is then placed in the posterior wall of the sinus and a second bone flap is removed, revealing the underlying dura. The craniotomy can be extended laterally over the orbital roofs as dictated by the surgical anatomy of the tumor. An incision is made in the dura and csf is liberally drained. With relaxation of the frontal lobes, the endoscope is advanced intracranially along the floor of the anterior fossa between the olfactory tracts. Endoscopic survey reveals the degree of intracranial tumor spread. Extracranial extensions of tumor are then exposed and removed from this superior approach.

Prosthetic dural graft material can be used to ensure a watertight seal in dural repair. The pedicled periosteal flap is interposed between the dura and the paranasal sinuses to reconstruct the base of the skull when appropriate. The nasoglabellar bone flap is repositioned using titanium microplates and screws. The skin incision is closed with careful attention to the aesthetic repair. The patient is monitored in the intensive care unit until neurologically stable and thereafter transferred to the ward until discharge from the hospital.

Case reports: Case 1.

This 64 year old female presented to our service with a 10 year history of a Rathke's cleft cyst for which she had undergone transcranial and transsphenoidal attempts at resection. Both surgeries were followed by recurrence. Her complaints at presentation were persistent panhypopituitarism, headaches, and new onset visual field deficits. Contrast-enhanced MRI of the skull base revealed a cystic suprasellar mass consistent with her previous diagnosis.

The patient underwent a fully endoscopic transglabellar approach to the floor of the anterior cranial fossa. The endoscope was advanced along the base of the skull between the olfactory tracts, and the optic apparatus was visualized. The cyst was adherent to the inferior surface of the optic chiasm. It was incised and its liquid contents were drained. The cyst wall was then dissected from the optic chiasm and removed in its entirety.

The patient was monitored in the intensive care unit overnight, and then on the ward for an additional 48 hours prior to discharge. No complications from surgery were observed and the patient's vision has steadily improved postoperatively. She remains asymptomatic at three-month follow up with a facial scar that is camouflaged in a transverse nasal skin crease.

Case 2.

This 56-year-old male presented to our service for evaluation of recurrent intrasellar craniopharyngioma. The patient underwent transsphenoidal resection 20 years prior to presentation with subsequent recurrence 2 years later. Transcranial resection and adjuvant radiation therapy were followed by two additional recurrences. These were treated with a second transsphenoidal resection and with gamma knife radiosurgery respectively. His presenting complaints included persistent panhypopituitarism and progressive loss of peripheral vision. Contrast-enhanced MRI demonstrated recurrent disease in the sella with cranial extension.

The patient underwent a fully endoscopic transglabellar approach to the suprasellar area. The endoscope was advanced along the base of the skull, where tumor was found to be densely adherent to the optic chiasm. The lesion was sharply dissected from the chiasm and entirely removed from the anterior fossa. A Teflon sponge was left in the suprasellar space as a marker of the extent of resection. Following this, the dura was reapproximated and the bone flap and skin incision were reapproximated.

An endoscopic transnasal approach to the sella was then performed. The rigid endoscope was advanced into the nostril and used to identify the sphenoid rostrum, which was resected. The floor of the sella was identified and removed to identify the intrasellar portion of the tumor. Tumor was removed until the Teflon marker and optic chiasm were observed, confirming the transglabellar margin of resection. An abdominal fat graft was used to fill the sphenoid sinus.

The patient was monitored in the intensive care unit overnight and transferred to the ward on the day after surgery, where he remained for an additional 48 hours prior to discharge. He suffered no neurological sequelae and remains disease-free with significant improvement in his visual field deficit at 6 month follow up. His facial scar is imperceptible.


Once considered to be "inoperable" due to the difficulties associated with surgical access, most anterior cranial fossa tumors with craniofacial extension can now be resected en bloc.1-4 Numerous transcranial and transfacial surgical approaches to the anterior skull base, orbits, and surrounding paranasal sinuses have been described.

The pioneering description of the transglabellar technique has been credited to Giordano, who at the turn of the 20th century described an approach to the pituitary gland via a bilateral paramedian nasofrontal incision.4 After glabellar degloving, ethmoidectomy, and midline anterior dissection Giordano had ready access to the sphenoid sinus and sella turcica. A decade later, Cushing used a transglabellar approach in his first pituitary adenoma resection for acromegaly, citing the benefits of the direct midline approach.6

In 1963 Ketcham7 described a combined intracranial and transfacial approach to tumors of the paranasal sinuses based upon earlier work by Smith.1 Ketcham's procedure detailed the use of a bicoronal skin incision and limited frontal craniotomy followed by a modified Weber-Ferguson incision and maxillectomy. The resultant exposure allowed for evaluation of the extent of intracranial disease and delivery of tumor through the facial incision. The iatrogenic skull base defect was reconstructed with split-thickness skin grafts. Postoperative meningitis resulting in fatality was reported in one case.

Use of combined transfrontal and transfacial techniques have since been elaborated upon.8-11 The use of lumbar drains and of pedicled pericranial flaps and bone grafts in reconstruction of the skull base has reduced the incidence of postoperative csf leak and infection.2,12-14 In order to minimize the sequelae associated with frontal lobe retraction and the untoward cosmetic results associated with facial incisions, these approaches have become progressively less invasive. Variously fashioned frontal and supraorbital osteotomies that provide equivalent access to the anterior cranial fossa and surrounding cavities without the need for additional facial incisions have been described. The transbasal approach, first described by Tessier15 in the management of craniofacial deformities and then adapted by Derome14 to the resection of skull base tumors, exposes the anterior skull base, orbits, and paranasal sinuses via a bifrontal craniotomy and limited frontal lobe retraction.2 Jane16 and Liangfu17 incorporated the superior orbital rims and parts of the orbital roofs into the frontal craniotomy, thereby obtaining greater access to the orbit and midline structures, including the planum, sella turcica, anterior cerebral circulation, and clivus.

Variations upon the transbasal approach that include separate osteotomies of the nasoglabellar complex were reported by Cox18 and Sekhar.3 Based upon extensive experience with the subcranial approach in the setting of craniofacial and skull base trauma,19,20 Raveh21,22 reported en bloc osteotomy of the frontonasal segment in the management of anterior skull base tumors. These techniques augment access to midline skull base the without the need for brain retraction by extending the bifrontal craniotomy inferiorly.

Moore23 and Jung24 both retrospectively compared perioperative morbidity of patients who underwent resection of anterior cranial fossa tumors via either the "classical" approach (bifrontal craniotomy combined with lateral rhinotomy) or a subcranial nasoglabellar osteotomy. Decreases in operating time, intraoperative blood loss, ICU recovery time, and overall length of hospital stay in the groups of patients receiving the transglabellar procedure were observed by both authors. Jung also noted superior intraoperative exposure and complete preservation of olfaction in these patients while documenting a greater incidence of severe complications (sepsis, meningitis, disseminated intravascular coagulation, csf leak) in the group that received the classical procedure.

Beals's25 summary of the benefits of the transfrontal techniques calls attention to the reduced working distance that the direct midline approaches provide. He proposes a classification scheme for the various approaches that is based upon the anatomic sites of lesions and the levels of exposure required for their resection. The upper 3 approaches in this system provide wide access to the anterior cranial fossa, nasopharynx, and clivus. This exposure is predicated upon facial degloving and frontal disassembly.

Persing,26 however, stated that bifrontal bone flaps are unnecessarily extensive and disfiguring. Following reflection of a bicoronal flap, he separately removed the anterior wall of the frontal sinus and then fashioned the frontal osteotomy on a burr hole placed in the inner table of the sinus to access the anterior fossa. Persing emphasized the ability to obtain "almost limitless exposure" through a limited craniotomy that was extended only as dictated by the dimensions of the tumor.

This theme is reinforced by Jho,5 who argues that the extensive frontal bone flaps that characterize the transcranial techniques do not contribute to the desired subcranial exposure and that the reflected bicoronal scalp flap itself occupies some of the critically scarce midline space. In his technique, a limited nasoglabellar approach provides the same access that is obtained in the more extensive transfrontal procedures. Jho makes use of a small incision between the eyebrows that crosses the nasion. The resultant scar is hidden in a horizontal skin crease and is hardly perceptible after healing, especially in patients who wear glasses. Nasoglabellar degloving generates a pericranial flap for later reconstruction of the skull base. The osteotomy is limited to the nasoglabellar complex and based on a burr hole in the posterior wall of the frontal sinus; resection of bone can be extended laterally to include the orbital roofs as necessary. The approach is limited to only those steps that directly contribute to exposure of the paramedian skull base.

Although Jho states that this procedure is "not an acrobatic minimally invasive technique," appreciation of deeper structures within the anterior fossa and paranasal sinuses may be difficult through a restricted opening. The case material we present underscores how well the use of rigid endoscopy suits the surgical management of combined intracranial craniofacial disease. Where extensive craniofacial disassembly was once required, the minimally invasive nature of endoscopic exploration allows surgical exposure without excessive manipulation of surrounding tissues. An endoscopic approach relies upon the ability of the rigid endoscope to overcome any barriers to visualization that a diminutive craniotomy may pose. The ease with which slender Hopkins rod endoscopes can be maneuvered in the space between the frontal lobes and the base of the skull obviates the need for prolonged brain retraction. Because the endoscope can be advanced directly to the level of the lesion, the effective operating distance is significantly reduced. The use of endoscopes with 30° and 70° lenses allows panoramic views of the anterior fossa and surrounding sinuses as well as visualization around anatomical "corners" that normally obscure gross and microscopic observation.

Under endoscopic imaging the full extent of intracranial disease and craniofacial extension can be assessed with minimal disturbance, and en bloc resection can be achieved. Through a limited transglabellar craniotomy, exposures that encompass the floor of the anterior fossa, the paranasal sinuses, and the upper clivus can be obtained without the need for scalp flaps or large frontal craniotomies. A more conservative endoscopic approach benefits patients without compromising the prospects for complete tumor resection.


The adaptation of rigid endoscopy to the resection of anterior cranial fossa tumors with craniofacial extension is exemplary of the trend toward minimally invasive techniques in this setting. The flexibility of the rigid endoscope as an imaging tool allows for the elimination of unnecessary surgical steps that may contribute to operative morbidity. This operative efficiency comes at no cost to surgical success.

  1. Smith RR, Klopp CT, Williams JM. Surgical treatment of cancer of the frontal sinus and adjacent areas. Cancer 1954;7:991-994
  2. Arita N, Mori S, Sano M, et al. Surgical treatment of tumors in the anterior skull base using the transbasal approach. Neurosurgery 1989;24:379-384
  3. Sekhar LN, Nanda A, Sen CN, et al. The extended frontal approach to tumors of the anterior, middle, and posterior skull base J Neurosurg 1992;76:198-206
  4. Artico M, Pastore FS, Fraioli B, et al. The contribution of Davide Giordano (1864-1954) to pituitary surgery: the transglabellar-nasal approach. Neurosurgery. 1998;42:909-911
  5. Jho HD, Ko Y. Glabellar approach: simplified midline anterior skull base approach. Minim Invas Neurosurg 1997;40:62-67
  6. Walker AE. A history of Neurological Surgery. New York: Hafner Publishing Co.,1967:158-162
  7. Ketcham AS, Wilkins RH, Van Buren JM, et al. A combined intracranial facial approach to the paranasal sinuses. Am J Surg 1963;166:698-703
  8. Johns ME, Kaplan MJ, Jane JA, et al. Supraorbital rim approach to the anterior skull base. Laryngoscope 1984;94:1137-1139
  9. Sundaresan N, Shah JP. Craniofacial resection for anterior skull base tumors. Head Neck Surg 1988;10:219-224
  10. Bavetta S, McFall MR, Afshar F, et al. Schwannoma of the anterior cranial fossa and paranasal sinuses: Br J Neurosurg 1993; 7:697-700
  11. McCutcheon IE, Blacklock JB, Weber RS, et al. Anterior transcranial (craniofacial) resection of tumors of the paranasal sinuses: surgical technique and results Neurosurgery 1996; 38:471-479
  12. Schramm VL, Myers EN, Maroon JC. Anterior skull base surgery for begin and malignant disease. Laryngoscope 1979;89:1077-1091
  13. Jackson IT, Marsh WR. Anterior craninal fossa tumors. Ann Plast Surg 1983;11:479-489
  14. Derome PJ. The transbasal approach to tumors invading the base of the skull. In: Schmidek HH, Sweet WH(eds): Operative Neurosurgical Technique, ed 2. Orlando, Grume & Stratton, 1988:619-633
  15. Tessier P, Guiot G, Derome P. Orbital hypertelorism. II. Definite treatment of orbital hypertelorism (OR.H.) by craniofacial or by extracranial osteotomies. Scand J Plast Reconstr Surg 1973;7:39-58
  16. Jane JA, Park TS, Pobereskin LH, et al. The supraorbital approach: technical note. Neurosurgery 1982;11:537-542
  17. Liangfu Z, Huanhuan G, Shiqi L, et al. An extensive subfrontal approach to the lesions involving the skull base. Chinese Medical Journal 1995;108:407-412
  18. Cox VS, Rimell FL, Marenttete LJ, et al. Ethmoidal cemento-ossifying fibroma: the transglabellar/subcranial approach. Otolaryngol Head Neck Surg 1996;114:335-338
  19. Raveh J, Vuillemin T, Sutter F. Subcranial management of 395 combined frontobasal-midface fractures. Arch Otolaryngol Head Neck Surg 1988;114:1114-1122
  20. Raveh J, Vuillemin T. The surgical one-stage management of combined cranio-maxillo-facial and frontobasal fractures. Advantages of the subcranial approach in 374 cases. J Cranio-Max-Fac Surg 1988;16:160-172
  21. Raveh J, Laedrach K, Speiser M, et al. The subcranial approach for fronto-orbial and anteroposterior skull-base tumors. Arch Otolaryngol Head Neck Surg 1993;119:385-393
  22. Raveh J, Turk JB, Ladrach K, et al. Extended anterior subcranial approach for skull base tumors: long-term results. J Neurosurg 1995;82:1002-1010
  23. Moore CE, Ross DA, Marentette LJ. Subcranial approach to tumors of the anterior cranial base: analysis of current and traditional surgical techniques. Otolaryngol Head Neck Surg 1999;120:387-390
  24. Jung TM, TerKonda RP, Haines SJ, et al. Outcome analysis of the transglabellar/subcranial approach for lesions of the anterior cranial fossa: a comparison with the classic craniotomy approach. Otolaryngolog Head Neck Surg 1997;116:642-646
  25. Beals SP, Joganic EF, Hamilton MG, et al. Posterior skull base transfacial approaches. Clin Plast Surg 1995;22:491-511
  26. Persing JA, Jane JA, Levine PA, et al. The versatile frontal sinus approach to the floor of the anterior cranial fossa. Technical note. J Neurosurg 1990;72:513-516