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Jae Sung Park, Seunghoon Lee, Sang-Ku Park, Jeong-A Lee and Kwan Park

OBJECTIVE

Microvascular decompression (MVD) is widely considered the treatment of choice for hemifacial spasm (HFS), but not all patients immediately benefit from it. Numerous electrophysiological tests have been employed to monitor the integrity of the facial nerve prior to, during, and after MVD treatment. The authors sought to verify if facial motor evoked potential (FMEP) with paired transcranial magnetic stimulation (pTMS) can be utilized as a tool to predict prognosis following MVD for HFS.

METHODS

FMEP using pTMS was performed preoperatively and postoperatively for 527 HFS patients who underwent an MVD treatment. Various interstimuli intervals (ISIs), which included 2, 10, 20, 25, 30, 75, and 100 msec, were applied for each paired stimulation and pTMS(%) was obtained. A graph of pTMS(%) versus each ISI was drawn for every patient and its pattern was analyzed in accordance with patients’ clinical outcomes.

RESULTS

With ISIs of 75 and 100 msec, pTMS(%) was physiologically further inhibited, whereas it was relatively facilitated under ISIs of 20, 25, and 30 msec; loss of this specific pattern, that is, further inhibition-relative facilitation, indicated impaired integrity of the facial nerve. Those patients who immediately benefited from an MVD and experienced no relapse tended to show proper restoration of this further inhibition-relative facilitation pattern (p = 0.01). Greater resemblance between the physiological pattern of pTMS(%) and postoperative pTMS(%) was correlated to better outcome (p = 0.019).

CONCLUSIONS

A simple linear graph of pTMS(%) versus each ISI may be a helpful tool to predict prognosis for HFS following an MVD.

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Myung-Jin Park, In-Chul Park, Jin-Heang Hur, Mi-Suk Kim, Hyung-Chan Lee, Sang-Hyeok Woo, Kyung-Hee Lee, Chang-Hun Rhee, Seok-Il Hong and Seung-Hoon Lee

Object. Expression of matrix metalloproteinases (MMPs) has been postulated to play a central role in brain tumor invasion; however, its underlying mechanism is not yet fully understood. In the present study, by assessing the effect of a specific p38 mitogen-activated protein kinase (MAPK) inhibitor, SB203580, on the secretion of MMPs and in vitro invasion of various glioma cells, the authors attempt to define the role of the p38 MAPK pathway in the regulation of MMPs and tissue inhibitors of metalloproteinases (TIMPs) activated by phorbol ester (phorbol-12-myristate-13-acetate [PMA]) in the D54 human glioblastoma cell line.

Methods. The activation of MAPKs was determined using Western blot analysis after addition of phospho-specific antibodies against these kinases, the status of MMPs and TIMPs was analyzed using gelatin zymography and Western blot analysis, and the invasion rate of D54 cells and other glioma cells was analyzed using a modified Boyden chamber assay. Treatment of D54 cells with PMA activated two distinct MAPKs, extracellular signal-regulated kinase (ERK) 1/2 and p38 MAPK, but not c-Jun N-terminal kinase/stress-activated protein kinase. Induction of MMP-9 production and MMP-2 activation by PMA were blocked by SB203580, a specific inhibitor of p38 MAPK, but not by PD98059, a specific inhibitor of ERK 1/2. In addition, PMA-induced downregulation of TIMP-1 and TIMP-2 secretion and upregulation of the membrane type 1 MMP, a major activator of MMP-2 on the cell surface, were reversed by SB203580 in these cells; the PMA-induced increase of invasion in vitro decreased when SB203580 was added to the top compartment of a modified Boyden chamber; and the inhibitor also reduced the MMP secretion and PMA-induced in vitro invasion in various glioma cell lines.

Conclusions. These results indicate that activation of p38 MAPK by PMA plays a central role in the regulation of MMPs and TIMPs in D54 cells, which has a major influence in tumor invasion and metastasis. Furthermore, inhibition of p38 MAPK by SB203580 blocked the secretion of MMPs and in vitro invasion of various glioma cells, underscoring a possible role of p38 MAPK inhibitors as antiinvasive and/or antimetastatic agents of malignant gliomas.

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Constantin Tuleasca, Lorenzo Giammattei, Roy Thomas Daniel and Marc Levivier

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Wendy Guo, Bang-Bon Koo, Jae-Hun Kim, Rafeeque A. Bhadelia, Dae-Won Seo, Seung Bong Hong, Eun Yeon Joo, Seunghoon Lee, Jung-Il Lee, Kyung Rae Cho and Young-Min Shon

OBJECTIVE

The anterior thalamic nucleus (ATN) is a common target for deep brain stimulation (DBS) for the treatment of drug-refractory epilepsy. However, no atlas-based optimal DBS (active contacts) target within the ATN has been definitively identified. The object of this retrospective study was to analyze the relationship between the active contact location and seizure reduction to establish an atlas-based optimal target for ATN DBS.

METHODS

From among 25 patients who had undergone ATN DBS surgery for drug-resistant epilepsy between 2016 and 2018, those who had follow-up evaluations for more than 1 year were eligible for study inclusion. After an initial stimulation period of 6 months, patients were classified as responsive (≥ 50% median decrease in seizure frequency) or nonresponsive (< 50% median decrease in seizure frequency) to treatment. Stimulation parameters and/or active contact positions were adjusted in nonresponsive patients, and their responsiveness was monitored for at least 1 year. Postoperative CT scans were coregistered nonlinearly with preoperative MR images to determine the center coordinate and atlas-based anatomical localizations of all active contacts in the Montreal Neurological Institute (MNI) 152 space.

RESULTS

Nineteen patients with drug-resistant epilepsy were followed up for at least a year following bilateral DBS electrode implantation targeting the ATN. Active contacts located more adjacent to the center of gravity of the anterior half of the ATN volume, defined as the anterior center (AC), were associated with greater seizure reduction than those not in this location. Intriguingly, the initially nonresponsive patients could end up with much improved seizure reduction by adjusting the active contacts closer to the AC at the final postoperative follow-up.

CONCLUSIONS

Patients with stimulation targeting the AC may have a favorable seizure reduction. Moreover, the authors were able to obtain additional good outcomes after electrode repositioning in the initially nonresponsive patients. Purposeful and strategic trajectory planning to target this optimal region may predict favorable outcomes of ATN DBS.

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Dae Won Kim, Won Sik Eum, Sang Ho Jang, Jinseu Park, Dong-Hwa Heo, Seung-Hoon Sheen, Hae-Ran Lee, Haeyong Kweon, Seok-Woo Kang, Kwang-Gill Lee, Se Youn Cho, Hyoung-Joon Jin, Yong-Jun Cho and Soo Young Choi

Object

To improve the safety of dura repair in neurosurgical procedures, a new dural material derived from silk fibroin was evaluated in a rat model with a dura mater injury.

Methods

The authors prepared new, transparent, artificial dura mater material using silk fibroin from the silkworm, Bombyx mori. The cytotoxic and antiinflammatory effects of the artificial dura mater were examined in vitro and in vivo by histological examination, western blotting, and reverse transcription polymerase chain reaction analyses.

Results

The novel artificial dura mater was not cytotoxic. However, it efficiently reduced cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase expression as well as the expression of the proinflammatory cytokines IL-1β, IL-6, and tumor necrosis factor–α. Cerebrospinal fluid leakage did not occur after repair of the brain of craniotomized rats with the artificial dura mater material.

Conclusions

The new artificial dura mater described in this study appears to be safe for application in neurosurgical procedures and can efficiently inhibit inflammation without side effects or CSF leakage. Although the long-term effects of this artificial dura mater material need to be validated in larger animals, the results from this study indicate that it is suitable for application in neurosurgery.