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ESBS 2005: Skull Base Surgery: An Interdisciplinary Challenge
7th Congress of the European Skull Base Society held in association with
the 13th Congress of the German Society of Skull Base Surgery

18. - 21.05.2005, Fulda, Germany

Versatility of the subcranial approach and indications for combined procedures in extensive anterior and central skull base tumors

Meeting Contribution

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  • Joram Raveh - Cranio-Maxillofacial, Skull Base, Facial Plastic and Reconstructive Surgery, University Hospital, Bern, Switzerland
  • Kurt Laedrach - Cranio-Maxillofacial, Skull Base, Facial Plastic and Reconstructive Surgery, University Hospital, Bern, Switzerland

ESBS 2005: Skull Base Surgery: An Interdisciplinary Challenge. 7th Congress of the European Skull Base Society held in association with the 13th Congress of the German Society of Skull Base Surgery. Fulda, 18.-21.05.2005. Düsseldorf: German Medical Science GMS Publishing House; 2009. Doc05esbs05

DOI: 10.3205/05esbs05, URN: urn:nbn:de:0183-05esbs053

Published: January 27, 2009

© 2009 Raveh et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.




The major advantages of the subcranial approach as developed by us for intra- and extracranial lesions are particularly obvious in the management of extensive skull base tumors which represent the majority of the 222 cases in our series. Out of these 105 were malignant.

The subcranial approach enables by one and the same access from the anterior to the posterior direction, under direct vision, the dissection of the dura and exposure of the skull base planes avoiding frontal lobe retraction. This in contrast to the CFR approach mandating, apart from the craniotomy additional external approaches like the lateral rhinotomy including skin incisions or other transfacial approaches implying damage to uninvolved structures, so as to asses the tumor, often along with a piece meel removal. Thus, in spite of being less invasive the subcranial approach basically differs from the CFR and renders a board exposure and visualization of the tumor borders.


The subcranial concept enables on the one hand the simultaneous, stepwise exposure of the intracranial, nasal/paranasal, orbital and maxillary extensions/borders of the tumor and a radical en bloc removal. On the other the major advantage consists of the optimal visualization of tumor extensions involving the sphenoidal plane/sphenoid and the parasellar/clival regions, as well as the cavernous sinus, effacing or enclaving the optic nerve/chiasm the cavernous sinus and the ICA along with bone resorbtion. Exposure of these vital structures avoiding unnecessary damage, as well as the ascending and horizontal section of the ICA, the foramen lacerum including the resection of tumor extensions located at the sphenopalatinal, pterygopalatine fossa and infratemporal region enable radical en bloc removal. A more extensive lateral, infratemporal spread and involvement of the middle fossa justify a combination with zygomatic/temporal bone osteotomies. The indication for a combined Le Fort I osteotomy for the resection of tumor extensions involving the pterygoid, masseter and deeper retromaxillary layers. An additional hemimaxillectomy by the intraoral approach is given if the palate and the maxillary bone are involved.

The reconstruction of the skull base and sealing the defects following dura resection and removal of the ethmoidal and sphenoidal planes is performed by using fascia lata. We do not opt for osseous or free flap reconstruction at this area. According to our experience in 222 cases this is sufficient and the correct technique undermining the borders enable a watertight alignment reducing the complications such as: CSF leak or hermiation of the brain tissue, to absolute minimum. The reconstruction of vast fronto-naso-orbital defects following the removal of extensive skull base tumors using different techniques including bone and soft tissue grafts, revascularized free flaps and allomaterials such as: bone source, mesh or resorbable materials have proved to be utmost successful. For particular complex cases refinements and modifications have been developed by us accordingly.

The subcranial approach was developed by us 1978 for the management of extensive combined fronto-naso-orbital and skull base injuries including optic nerve compression, for fronto-orbital advancement in congenital anomalies/hypertelorism and skull base tumors. Although in the 2 previous decades often different terms than the subcranial approach were used and the fronto-nasal osteotomies differ in comparison to the tumor cases the concept and it’s major advantages remain the same [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14].

A critical evaluation of the contribution of CAS/navigation based on our experience (21) reveals that in spite of being less invasive and damaging than the CFR approaches, the broad exposure under direct vision by the subcranial techniques, the anatomical land marks are clearly visible, thus reducing the indication for CAS significantly. According to our experience the navigation is mainly useful in those cases with destruction of the bone leading to an aberrant anatomical configuration – particularly at the central skull base region – enabling a more secure procedure.

According to the submission guidelines for this contribution the description of the management of extremely interesting cases, as well as further details of the approach, pitfalls, illustrations, tables and further more would have been beyond the scope of this short report. The subcranial approach gained on popularity – on behalf of a better understanding and further crucial aspects we refer to a few representative publications of ours and others [1] [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24].

Patients, evaluation and results

Out of the 222 benign and malignant cases 104 managed 1978–1990 were already described [7] and are not be included in this report. The second series of 118 tumors included 58 malignant tumors managed in a prospective manner – the preoperative evaluation board consisted of neuroradiology, neurosurgery and included CT-scans, MRI, angiography and embolization. The postoperative follow up sequence and images were performed according to the same protocol – including the adjuvant radio- and chemotherapy. The staging of the 58 malignant cases was performed according to the ajcc. The majority of this cases was utmost extensive – T4a and T4b included 29% and 54,2% respectively. Only 16,8% were T3. Yet, the categories in this and other staging systems compose each heterogeneous groups including different tumor spread variations and are mostly ineffective in stratifying the cases into clinically relevant categories. As a tertiary referral centre we get tumors in an utmost advanced stage, often including all or at least several of the locations in one and the same patient. Thus an interseries comparison is actually impossible. Extensive involvement of the dura, brain as well as the parasellar region including the optic nerve chiasm and cavernous sinus further such combinations of delicate locations should have a significant prognostic influence concerning the outcome and recurrence rate.

In 5 years the overall and relapse free survival were 67% and 60% respectively and after 10 years overall and relapse free survival were 65% and 42% respectively. The subcranial approach enabled the reduction of complications such as: (N-patients) CSF-Leak (2), Meningitis (0), Pneumocranium (3), Brain edema (1), Enophthalmus (5), Telecanthus (3), Optic nerve / reduced vision (2), Diplopia (2), Amaurosis (0), significantly. The reconstruction of the skull base and the fronto-naso-orbital region with fascia lata and grafts enabled apart from resorbtion of bone grafts in 2 patients, optimal aesthetic and functional results. In regard to the advantages of the subcranial approach and in spite of the extensive resections, the ICU mean stay was reduced to 1,5 days and the hospitalization period was reduced to 12,5 days. The subcranial approach enables major advantages, as well as an utmost favourable quality of life.


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