Two-Stage Skull Base Surgery for Tumours Extending to the Sub- and Epidural Spaces

Summary  The surgical management of extensive skull base neoplasms, which often extend to both the sub- and epidural spaces, is still a great challenge with considerable risk. The authors report 12 cases in which a two-stage operation was performed for such nonmalignant tumours.  The series consisted of four cavernous sinus meningiomas, one sphenoid-ridge meningioma, one cerebello-pontine angle meningioma, three pituitary adenomas, two chordomas, and one fibroma. Our operative strategy involved removal of the epidural part of the tumour and extensive skull base reforming during the first stage. After approximately one month, the second stage operation was performed by removing the residual subdural parts and the affected dura, which were less vascular, with dural plasty and subsequent spinal drainage. No complications such as cerebrospinal fluid (CSF) leakage or infection were observed. During the long-term follow-up (1.4 to 4.6 years, with a mean of 2.7 years), tumour recurrence was observed in a single case.  In conclusion, the major advantages of this procedure were as follows: [1] improvement of the total removal rate, [2] prevention of postoperative CSF leak and infection, [3] residual tumours were avascular, necrotic, and dwindling, and also shifted outwards resulting in less adhesions to the brain. Although it may counter the trend toward less invasive procedures, the two-staged skull base surgery warrants serious consideration as an option for the management of patients with such extensive cranial base tumours.