Surgical outcomes of the minimum anterior and posterior combined transpetrosal approach for resection of retrochiasmatic craniopharyngiomas with complicated conditions
Authors: Kunihiro Noritsugu , Goto Takeo , Ishibashi Kenichi , Ohata Kenji 
Published: November 2013

Object
Retrochiasmatic craniopharyngiomas are surgically challenging tumors. Retrochiasmatic craniopharyngiomas with complicated conditions such as large diameter, major calcification, or significant extension to the third ventricle or posterior fossa present surgical challenges; moreover, recurrent retrochiasmatic craniopharyngiomas are particularly formidable challenges. Although the transpetrosal approach to retrochiasmatic craniopharyngiomas published by Hakuba in 1985 can provide unique advantageous exposure of the retrochiasmatic area to allow safe neurovascular dissection and facilitate radical tumor removal, the procedure is viewed as complicated and time consuming and has a high risk of damaging hearing functions. The authors have modified Hakuba's technique to minimize petrosectomy and reduce surgical complications and have applied this modified approach to retrochiasmatic craniopharyngiomas with complicated conditions. In this study, the authors describe their technique and surgical outcomes to elucidate the role of this modified transpetrosal approach for retrochiasmatic craniopharyngiomas with complicated conditions. This is the first study to report surgical outcomes of the transpetrosal approach for retrochiasmatic craniopharyngiomas.

Methods
Between 1999 and 2011, the minimum anterior and posterior combined (MAPC) transpetrosal approach, which is a modification of Hakuba's transpetrosal approach, was applied in 16 cases of retrochiasmatic craniopharyngiomas with complicated conditions. Eight cases were recurrent tumors, 4 had previously received radiotherapy, 11 had a large diameter, 10 had large calcification, 15 had superior extension of the tumor into the third ventricle, and 10 had a posterior extension of the tumor that compressed the midbrain and pons. In all 16 patients, more than 2 of these complicated conditions were present. The follow-up duration ranged from 0.8 to 12.5 years (mean 5.3 years). Surgical outcomes assessed were the extent of resection, surgical complications, visual function, endocrinological status, and neuropsychological function. Five-year and 10-year recurrence-free survival rates were also calculated.

Results
Gross-total or near-total resection was achieved in 15 cases (93.8%). Facial nerve function was completely maintained in all 16 patients. Serviceable hearing was preserved in 15 cases (93.8%). Visual function improved in 13 out of 14 cases (92.9%) that had visual disturbance before surgery. None of the patients experienced deterioration of their visual function. Twelve cases had endocrinological deficit and received hormonal replacement before surgery. New endocrinological deficit occurred in 2 cases (12.5%). Neuropsychological function was maintained in 14 cases (87.5%) and improved in 1 case (6.3%). One case that had received previous conventional radiotherapy treatment showed a gradual decline in neuropsychological function. The 5-year and 10-year recurrence-free survival rates were both 86.5%.

Conclusions
The authors obtained good results by using the MAPC transpetrosal approach for the removal of retrochiasmatic craniopharyngiomas with complicated conditions. The MAPC transpetrosal approach should be considered as a therapeutic option for selected cases of retrochiasmatic craniopharyngiomas with complicated conditions.