Ji Woong Oh, Kyoung Su Sung, Ju Hyung Moon, Eui Hyun Kim, Won Seok Chang, Hyun Ho Jung, Jin Woo Chang, Yong Gou Park, Sun Ho Kim, and Jong Hee Chang
This study investigated long-term follow-up data on the combined pituitary function test (CPFT) in patients who had undergone transsphenoidal surgery (TSS) for nonfunctioning pituitary adenoma (NFPA) to determine the clinical parameters indicative of hypopituitarism following postoperative Gamma Knife surgery (GKS).
Between 2001 and 2015, a total of 971 NFPA patients underwent TSS, and 76 of them (7.8%) underwent postoperative GKS. All 76 patients were evaluated with a CPFT before and after GKS. The hormonal states were analyzed based on the following parameters: relevant factors before GKS (age, sex, extent of resection, pre-GKS hormonal states, time interval between TSS and GKS), GKS-related factors (tumor volume; radiation dose to tumor, pituitary stalk, and normal gland; distance between tumor and stalk), and clinical outcomes (tumor control rate, changes in hormonal states, need for hormone-related medication due to hormonal changes).
Of the 971 NFPA patients, 797 had gross-total resection (GTR) and 174 had subtotal resection (STR). Twenty-five GTR patients (3.1%) and 51 STR patients (29.3%) underwent GKS. The average follow-up period after GKS was 53.5 ± 35.5 months, and the tumor control rate was 96%. Of the 76 patients who underwent GKS, 23 were excluded due to pre-GKS panhypopituitarism (22) or loss to follow-up (1). Hypopituitarism developed in 13 (24.5%) of the remaining 53 patients after GKS. A higher incidence of post-GKS hypopituitarism occurred in the patients with normal pre-GKS hormonal states (41.7%, 10/24) than in the patients with abnormal pre-GKS hormonal states (10.3%, 3/29; p = 0.024). Target tumor volume (4.7 ± 3.9 cm3), distance between tumor and pituitary stalk (2.0 ± 2.2 mm), stalk dose (cutoffs: mean dose 7.56 Gy, maximal dose 12.3 Gy), and normal gland dose (cutoffs: maximal dose 13.9 Gy, minimal dose 5.25 Gy) were factors predictive of post-GKS hypopituitarism (p < 0.05).
This study analyzed the long-term follow-up CPFT data on hormonal changes in NFPA patients who underwent GKS after TSS. The authors propose a cutoff value for the radiation dose to the pituitary stalk and normal gland for the prevention of post-GKS hypopituitarism.
Eui Hyun Kim, Jihwan Yoo, In-Ho Jung, Ji Woong Oh, Ju-Seong Kim, Jin Sook Yoon, Ju Hyung Moon, Seok-Gu Kang, Jong Hee Chang, and Tae Hoon Roh
The insula is a complex anatomical structure. Accessing tumors in the insula remains a challenge due to its anatomical complexity and the high chance of morbidity. The goal of this study was to evaluate the feasibility of an endoscopic transorbital approach (ETOA) to the insular region based on a cadaveric study.
One cadaveric head was used to study the anatomy of the insula and surrounding vessels. Then, anatomical dissection was performed in 4 human cadaveric heads using a dedicated endoscopic system with the aid of neuronavigation guidance. To assess the extent of resection, CT scanning was performed before and after dissection. The insular region was directly exposed by a classic transcranial approach to check the extent of resection from the side with a classic transcranial approach.
The entire procedure consisted of two phases: an extradural orbital phase and an intradural sylvian phase. After eyelid incision, the sphenoid bone and orbital roof were extensively drilled out with exposure of the frontal and temporal dural layers. After making a dural window, the anterior ramus of the sylvian fissure was opened and dissected. The M2 segment of the middle cerebral artery (MCA) was identified and traced posterolaterally. A small corticectomy was performed on the posterior orbital gyrus. Through the window between the lateral lenticulostriate arteries and M2, the cortex and medulla of the insula were resected in an anteroposterior direction without violation of the M2 segment of the MCA or its major branches. When confirmed by pterional craniotomy, the sylvian fissure and the MCA were found to be anatomically preserved. After validation of the feasibility and safety based on a cadaveric study, the ETOA was successfully performed in a patient with a high-grade glioma (WHO grade III) in the right insula.
The transorbital route can be considered a potential option to access tumors located in the insula. Using an ETOA, the MCA and its major branches were identified and preserved while removal was performed along the long axis of the insula. In particular, lesions in the anterior part of the insula are most benefited by this approach. Because this approach was implemented in only one patient, additional discussion and further verification is required.