Aim: The management of large lesions of the skull base, such as vestibular schwanommas (VS), meningiomas (MEN) or
pituitary adenomas (PA), is challenging, with microsurgery remaining the main treatment option. Planned subtotal resection is
now being increasingly considered to reduce the risk of neurological deficits following complete resection. The residual part of
the tumor can then be treated with Gamma Knife Radiosurgery (GKR) to achieve long-term growth control.
Methods: This case series documents early results with planned subtotal resection followed by GKR in Lausanne University
Hospital, between July 2010 and March 2012. There were 24 patients who underwent surgery, with 22 having already
undergone GKR and 2 waiting for GKR. We analyzed clinical symptoms for all patients, as well as audiograms, ophthalmological
and endocrinological tests, when indicated.
Results: Nine patients had VS surgery (mean diameter 35 mm; range 30-44.5) through a retrosigmoid approach. There were
no post-operative facial nerve deficits. Of the 3 patients whom had useful hearing pre-operatively, this improved in 2 and
remained stable in 1. Four patients with clinoid MEN (mean diameter 26.5 mm; range 17-42) underwent subtotal resection
of the tumor, and the component in the cavernous sinus was later treated with GKR. The visual status remained stable in 3
patients and one had complete visual recovery. 4 patients underwent subtotal resection of petro-clival MEN (mean diameter
36 mm; range 32-42): 3 had House-Brackmann (HB) grade 2 facial function that recovered completely; one continues to
have HB grade 4 facial deficit following surgery. Of the 7 patients with PA (mean diameter 34.5 mm; range 20-54.5), 2 had
acromegaly, the others were non functional PA. Six patients underwent trans-sphenoidal surgery, while one patient had a
transcavernous sinus resection of the tumor (with prior staged trans-sphenoidal surgery). Visual status improved in 3 patients
while the others remained stable. Two patients had transient diabetes insipidus following surgery. Up to now, no additional
deficit or worsening has been reported after GKR.
Conclusions: Our data suggest that planned subtotal resection has an excellent clinical outcome with respect to preservation
of cranial nerves, and other neurological functions, and a good possibility of recovery of many of the pre-operative cranial
nerve dysfunctions. The results in terms of tumor control following GKR need further long-term evaluation.