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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.

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Un Yong Choi, Jeong Yoon Park, Kyung Hyun Kim, Sung Uk Kuh, Dong Kyu Chin, Keun Su Kim and Yong Eun Cho


Clinical results for unilateral pedicle screw fixation after lumbar interbody fusion have been reported to be as good as those for bilateral instrumentation. However, no studies have directly compared unilateral and bilateral percutaneous pedicle screw fixation after minimally invasive surgery (MIS) for transforaminal lumbar interbody fusion (TLIF). The purpose of this study was to determine whether unilateral percutaneous pedicle screw fixation is comparable with bilateral percutaneous pedicle screw fixation in 1-segment MIS TLIF.


This was a prospective randomized study of 53 patients who underwent unilateral or bilateral percutaneous pedicle screw fixation after MIS TLIF for 1-segment lumbar degenerative disc disease. Twenty-six patients were assigned to a unilateral percutaneous pedicle screw fixation group and 27 patients were assigned to a bilateral percutaneous pedicle screw fixation group. Operative time, blood loss, clinical outcomes (that is, Oswestry Disability Index [ODI] and visual analog scale [VAS] scores), complication rates, and fusion rates were assessed using CT scanning 2 years after surgical treatment.


The 2 groups were similar in age, sex, preoperative diagnosis, and operated level, and they did not differ significantly in the length of follow-up (27.5 [Group 1] vs 28.9 [Group 2] months) or clinical results. Both groups showed substantial improvements in VAS and ODI scores 2 years after surgical treatment. The groups differed significantly in operative time (unilateral 84.2 minutes; bilateral 137.6 minutes), blood loss (unilateral 92.7 ml; bilateral, 232.0 ml), fusion rate (unilateral 84.6%; bilateral 96.3%), and postoperative scoliotic change (unilateral 23.1%; bilateral 3.7%).


Unilateral and bilateral screw fixation after MIS TLIF produced similar clinical results. Although perioperative results were better with unilateral screw fixation, the long-term results were better with bilateral screw fixation, suggesting bilateral screw fixation is a better choice after MIS TLIF.