A Comparison of Operative Exposure Between the Le Fort I Osteotomy and the Exclusive Endoscopic Transnasal Approach for Middle and Lower Clival Lesions

Background: Neoplastic lesions of the middle and lower clivus are relatively rare and include but are not limited to chordomas, chondrosarcomas, teratomas, and metastatic disease. Although chemotherapy and radiation have a role in treatment, surgical resection/debulking is often necessary and controversy exists regarding approach. Classically, the Le Fort I osteotomy (LFO) served as the operative approach of choice, but the exclusive endoscopic transnasal (EETA) approaches may offer similar exposure while being minimally invasive.

Methods: Operative exposure was compared between the EETA approach and the LFO in 10 fixed cadaveric specimens. Specimens were imaged with 1.25-mm computed tomography then fixed in a Mayfield head clamp and registered to Brainlab Curve. After completing registration and visual confirmation of known landmarks, an EETA was performed followed by an LFO. Limits of laterality were measured at the opticocarotid recess (OCR), the foramen lacerum, and the hypoglossal canals. Vertical limits were compared from the tuberculum sellae to the midline lower extent of exposure. T-test was used to compare the values.

Results: Maximal lateral exposure at the OCR was 24.3 mm ± 2.7 mm versus 22.4 mm ± 1.3 mm for EETA versus LFO, respectively. Lateral exposure obtained at the level of the foramen lacerum was 22.5 mm ± 4.5 mm for the EETA versus 22.6 mm ± 1.2 mm for the LFO. At the hypoglossal canals, lateral reach was 37.7 mm ± 2.5 mm versus 54.1 mm ± 4.7 mm for EETA and LFO, respectively. Vertical extension was 57.1 mm ± 2.9 mm for EETA and 58.0 mm ± 1.3 mm for LFO.

Conclusions: Lesions of the middle and lower clivus have classically been approached with a Le Fort I osteotomy. Newer exclusive endoscopic transnasal approaches may offer similar exposure while being minimally invasive. In this study, both operative approaches were compared and similar exposure was achieved both craniocaudally and laterally at the level of the OCR and foramen lacerum. However, at the level of the hypoglossal canals, the Le Fort osteotomy provided greater exposure. Thus, lesions of the upper and middle clivus can be approached by either technique, but the Le Fort I osteotomy provides greater exposure for lower lateral clival lesions.