Influence of Propofol and Fentanyl on Deep Brain Stimulation of the Subthalamic Nucleus

We investigated the effect of propofol and fentanyl on microelectrode recording (MER) and its clinical applicability during subthalamic nucleus (STN) deep brain stimulation (DBS) surgery. We analyzed 8 patients with Parkinson's disease, underwent bilateral STN DBS with MER. Their left sides were done under awake and then their right sides were done with a continuous infusion of propofol and fentanyl under local anesthesia. The electrode position was evaluated by preoperative MRI and postoperative CT. The clinical outcomes were assessed at six months after surgery. We isolated single unit activities from the left and the right side MERs. There was no significant difference in the mean firing rate between the left side MERs (38.7+/-16.8 spikes/sec, n=78) and the right side MERs (35.5+/-17.2 spikes/sec, n=66). The bursting pattern of spikes was more frequently observed in the right STN than in the left STN. All the electrode positions were within the STNs on both sides and the off-time Unified Parkinson's Disease Rating Scale part III scores at six months after surgery decreased by 67% of the preoperative level. In this study, a continuous infusion of propofol and fentanyl did not significantly interfere with the MER signals from the STN. The results of this study suggest that propofol and fentanyl can be used for STN DBS in patients with advanced Parkinson's disease improving the overall experience of the patients.

Finite element analysis of peri-implant bone stresses induced by root contact of orthodontic microimplant / 대한치과교정학회지

OBJECTIVE: The aim of this study was to evaluate the biomechanical aspects of peri-implant bone upon root contact of orthodontic microimplant. METHODS: Axisymmetric finite element modeling scheme was used to analyze the compressive strength of the orthodontic microimplant (Absoanchor SH1312-7, Dentos Inc., Daegu, Korea) placed into inter-radicular bone covered by 1 mm thick cortical bone, with its apical tip contacting adjacent root surface. A stepwise analysis technique was adopted to simulate the response of peri-implant bone. Areas of the bone that were subject to higher stresses than the maximum compressive strength (in case of cancellous bone) or threshold stress of 54.8MPa, which was assumed to impair the physiological remodeling of cortical bone, were removed from the FE mesh in a stepwise manner. For comparison, a control model was analyzed which simulated normal orthodontic force of 5 N at the head of the microimplant. RESULTS: Stresses in cancellous bone were high enough to cause mechanical failure across its entire thickness. Stresses in cortical bone were more likely to cause resorptive bone remodeling than mechanical failure. The overloaded zone, initially located at the lower part of cortical plate, proliferated upward in a positive feedback mode, unaffected by stress redistribution, until the whole thickness was engaged. CONCLUSIONS: Stresses induced around a microimplant by root contact may lead to a irreversible loss of microimplant stability.

Electrode Position and the Clinical Outcome after Bilateral Subthalamic Nucleus Stimulation

We compared the surgical outcome with electrode positions after bilateral subthalamic nucleus (STN) stimulation surgery for Parkinson's disease. Fifty-seven patients treated with bilateral STN stimulations were included in this study. Electrode positions were determined in the fused images of preoperative MRI and postoperative CT taken at six months after surgery. The patients were divided into three groups: group I, both electrodes in the STN; group II, only one electrode in the STN; group III, neither electrode in the STN. Unified Parkinson's Disease Rating Scale (UPDRS), Hoehn and Yahr stage, and activities of daily living scores significantly improved at 6 and 12 months after STN stimulation in both group I and II. The off-time UPDRS III speech subscore significantly improved (1.6 +/- 0.7 at baseline vs 1.3 +/- 0.8 at 6 and 12 months, P < 0.01) with least L-dopa equivalent daily dose (LEDD) (844.6 +/- 364.1 mg/day at baseline; 279.4 +/- 274.6 mg/day at 6 months; and 276.0 +/- 301.6 mg/day at 12 months, P < 0.001) at 6 and 12 months after STN deep brain stimulation (DBS) in the group I. Our findings suggest that the better symptom relief including speech with a reduced LEDD is expected in the patients whose electrodes are accurately positioned in both STN.

Comparision of Mandible Changes on Three-Dimensional Computed Tomography image After Mandibular Surgery in Facial Asymmetry Patients / 영남의대학술지

BACKGROUND: When surgeons plan mandible ortho surgery for patients with skeletal class III facial asymmetry, they must be consider the exact method of surgery for correction of the facial asymmetry. Three-dimensional (3D) CT imaging is efficient in depicting specific structures in the craniofacial area. It reproduces actual measurements by minimizing errors from patient movement and allows for image magnification. Due to the rapid development of digital image technology and the expansion of treatment range, rapid progress has been made in the study of three-dimensional facial skeleton analysis. The purpose of this study was to conduct 3D CT image comparisons of mandible changes after mandibular surgery in facial asymmetry patients. MATERIALS & METHODS: This study included 7 patients who underwent 3D CT before and after correction of facial asymmetry in the oral and maxillofacial surgery department of Yeungnam University Hospital between August 2002 and November 2005. Patients included 2 males and 5 females, with ages ranging from 16 years to 30 years (average 21.4 years). Frontal CT images were obtained before and after surgery, and changes in mandible angle and length were measured. RESULTS: When we compared the measurements obtained before and after mandibular surgery in facial asymmetry patients, correction of facial asymmetry was identified on the "after" images. The mean difference between the right and left mandibular angles before mandibular surgery was 7degrees, whereas after mandibular surgery it was 1.5degrees. The right and left mandibular length ratios subtracted from 1 was 0.114 before mandibular surgery, while it was 0.036 after mandibular surgery. The differences were analyzed using the nonparametric test and the Wilcoxon signed ranks test (p<0.05). CONCLUSION: The system that has been developed produces an accurate three-dimensional representation of the skull, upon which individualized surgery of the skull and jaws is easily performed. The system also permits accurate measurement and monitoring of postsurgical changes to the face and jaws through reproducible and noninvasive means.

Postpartum Spontaneous Intrahepatic Hemorrhage and Hepatic Rupture in the HELLP Syndrome / 대한산부인과학회잡지

The HELLP syndrome, which is characterized by hemolysis, elevated liver enzymes and low platelets, complicates 4 to 14% of preeclamptic or eclamptic pregnancy. Its course is usually benign except when spontaneous hepatic rupture, a rare catastrophic event, threatens life. The authors have experienced one case of spontaneous hepatic rupture in HELLP syndrome during immediate postpartum period, which was treated with surgical intervention on the first postpartum day. We report this case with a brief review of the literatures.

A Study of Individual Variation of Responsiveness to Vagal Stimulation in Children (Nonspectral Analysis)

BACKGROUND: It is well known that there is wide individual variation of responsiveness when parasympathetic nervous system is stimulated physiologically, pathologically, and therapeutically. But no appropriate explanation is present for that yet. So the purpose of this study is to verify individual diversity of vagal tone during resting state and after vagal stimulation and to find factor that may significantly contribute to it. METHOD: We serially measured variation of heart period(VHP : sec) which had been known to be an accurate index of cardiac parasympathetic tone during resting state(VHPb) and after vagal stimulation by ice water application to face(VHPv). And we analyzed correlation between VHPb, VHPv and ratio of VHPv to VHPb(ratio). RESULT: There was wide variation of vagal tone both in resting state (VHPb : 0.025-0.161) and after vagal stimulation (VHPv : 0.087-0.661). VHPb could be classified into 3 groups according to stem and leaf distribution(group A : VHPb could be classified into 3 groups according to stem and leaf distribution(group A : VHPb0.1). The low VHPb group A showed dramatic increase in vagal tone after vagal stimulation (ratio 2.21-20.24 mean 7.7), on the other hand high VHPb group C did not (ratio 0.80-2.55 mean 1.39). There ws also a significant negative correlation between VHPb and ratio (r=0.69, p<0.001). CONCLUSION: These results suggest that there is wide individual diversity of responsiveness to vagal stimulation and magnitude of vagal tone in resting state is an important factor to determine the responsiveness to vagal stimulation.

The Onset of Coronary Artery Aneurysm and Changes of T Cell Subsets and the Effect of High Dose Gammaglobulin Therapy in Mucocutanenous Lymph Node Syndrome

We studied the onset of coronary artery aneurysm formation in 42 patients of Mucocutaneous lymph node syndrome (MCLS), the serial changes of T cell subsets, and serum immunoglobulin levels including lgG, lgA, lgM, in 13 patients among them during acute (before high dose gamma-globulin therapy ) and subacute phase (after gamma-globulin therapy) to evaluate the role of the immunoregulatory abnormalities in coronary artery aneurysm formation. The following results are obtainded : 1) The coronary artery aneurysm was found in 16 patients (38%). They were detected in between 6th and 13th day of illness with the mean of 8.8+/-2.1 day. 2) The total T lymphocyte (T1), helper T lymphocyte (T4), and helper/supperessor ratio (T4/T8) decreased during acute phase. 3) Following gamma-globulin therapy it showed a increase in T4,T8, and all immunoglobulines. Above results showed that the most of aneurysms developed during acute phase and suppressed, rather than enhanced, T cell function significantly contributed to aneurysm formation, whereas high dose gamma-globulin retarded or reversed this suppression which would be one of mechanism of beneficial effort of gamma-globulin in MCLS.