Chiman Jeon, Kyung Rae Cho, Jung Won Choi, Doo-Sik Kong, Ho Jun Seol, Do-Hyun Nam and Jung-Il Lee
This study was performed to evaluate the role of Gamma Knife radiosurgery (GKRS) as a primary treatment for central neurocytomas (CNs).
The authors retrospectively assessed the treatment outcomes of patients who had undergone primary treatment with GKRS for CNs in the period between December 2001 and December 2018. The diagnosis of CN was based on findings on neuroimaging studies. The electronic medical records were retrospectively reviewed for additional relevant preoperative data, and clinical follow-up data had been obtained during office evaluations of the treated patients. All radiographic data were reviewed by a dedicated neuroradiologist.
Fourteen patients were treated with GKRS as a primary treatment for CNs in the study period. Seven patients (50.0%) were asymptomatic at initial presentation, and 7 (50.0%) presented with headache. Ten patients (71.4%) were treated with GKRS after the diagnosis of CN based on characteristic MRI findings. Four patients (28.6%) initially underwent either stereotactic or endoscopic biopsy before GKRS. The median tumor volume was 3.9 cm3 (range 0.46–18.1 cm3). The median prescription dose delivered to the tumor margin was 15 Gy (range 5.5–18 Gy). The median maximum dose was 30 Gy (range 11–36 Gy). Two patients were treated with fractionated GKRS, one with a prescription dose of 21 Gy in 3 fractions and another with a dose of 22 Gy in 4 fractions. Control of tumor growth was achieved in all 14 patients. The median volume reduction was 26.4% (range 0%–78.3%). Transient adverse radiation effects were observed in 2 patients but resolved with improvement in symptoms. No recurrences were revealed during the follow-up period, which was a median of 25 months (range 12–89 months).
Primary GKRS for CNs resulted in excellent tumor control rates without recurrences. These results suggest that GKRS may be a viable treatment option for patients with small- to medium-sized or incidental CNs.
Chiman Jeon, Chang-Ki Hong, Kyung In Woo, Sang Duk Hong, Do-Hyun Nam, Jung-Il Lee, Jung Won Choi, Ho Jun Seol and Doo-Sik Kong
Tumors involving Meckel’s cave remain extremely challenging because of the surrounding complex neurovascular structures and deep-seated location. The authors investigated a new minimal-access technique using the endoscopic transorbital approach (eTOA) through the superior eyelid crease to Meckel’s cave and middle cranial fossa lesions and reviewed the most useful surgical procedures and pitfalls of this approach.
Between September 2016 and January 2018, the authors performed eTOA in 9 patients with tumors involving Meckel’s cave and the middle cranial fossa. The lesions included trigeminal schwannoma in 4 patients, meningioma in 2 patients, metastatic brain tumor in 1 patient, chondrosarcoma in 1 patient, and dermoid cyst in 1 patient. In 7 of the 9 patients, eTOA alone was performed, while the other 2 patients underwent a combined eTOA and endoscopic endonasal approach or retrosigmoid craniotomy. Data including details of surgical techniques and clinical outcomes were recorded.
Gross-total resection was performed in 7 of the 9 patients (77.8%). Four patients underwent extended eTOA (with lateral orbital rim osteotomy). Drilling of the trapezoid sphenoid floor, a middle fossa “peeling” technique, and full visualization of Meckel’s cave were applied to approach the lesions. Tumors were exposed and removed extradurally in 3 patients and intradurally in 6 patients. There was no postoperative CSF leak.
The eTOA affords a direct route to access Meckel’s cave and middle cranial fossa lesions. With experience, this novel approach can be successfully applied to selected skull base lesions. To achieve successful removal of the tumor, emphasis should be placed on the importance of adequately removing the greater sphenoid wing and vertical crest. However, because of limited working space eTOA may not be an ideal approach for posterior fossa lesions.
Yong Hwy Kim, Chiman Jeon, Young-Bem Se, Sang Duk Hong, Ho Jun Seol, Jung-II Lee, Chul-Kee Park, Dong Gyu Kim, Hee-Won Jung, Doo Hee Han, Do-Hyun Nam and Doo-Sik Kong
The endoscopic endonasal approach for treating primary skull base malignancies involving the clivus is a formidable task. The authors hypothesized that tumor involvement of nearby critical anatomical structures creates hurdles to endoscopic gross-total resection (GTR). The aim of this study was to retrospectively review the clinical outcomes of patients who underwent an endoscopic endonasal approach to treat primary malignancies involving the clivus and to analyze prognostic factors for GTR.
Between January 2009 and November 2015, 42 patients underwent the endoscopic endonasal approach for resection of primary skull base malignancies involving the clivus at 2 independent institutions. Clinical data; tumor locations within the clivus; and anatomical involvement of the cavernous or paraclival internal carotid artery, cisternal trigeminal nerve, hypoglossal canal, and dura mater were investigated to assess the extent of resection. Possible prognostic factors affecting GTR were also analyzed.
Of the 42 patients, 37 were diagnosed with chordomas and 5 were diagnosed with chondrosarcomas. The mean (± SD) preoperative tumor volume was 25.2 ± 30.5 cm3 (range 0.8–166.7 cm3). GTR was achieved in 28 patients (66.7%) and subtotal resection in 14 patients (33.3%). All tumors were classified as upper (n = 17), middle (n = 17), or lower (n = 8) clival tumors based on clival involvement, and as central (24 [57.1%]) or paramedian (18 [42.9%]) based on laterality of the tumor. Univariate analysis identified the tumor laterality (OR 6.25, 95% CI 1.51–25.86; p = 0.011) as significantly predictive of GTR. In addition, the laterality of the tumor was found to be a statistically significant predictor in multivariate analysis (OR 41.16, 95% CI 1.12–1512.65; p = 0.043).
An endoscopic endonasal approach can provide favorable clinical and surgical outcomes. However, the tumor laterality should be considered as a potential obstacle to total removal.