Feasibility of Eye Tracking Assisted Vestibular Rehabilitation Strategy Using Immersive Virtual Reality

OBJECTIVES: Even though vestibular rehabilitation therapy (VRT) using head-mounted display (HMD) has been highlighted recently as a popular virtual reality platform, we should consider that HMD itself do not provide interactive environment for VRT. This study aimed to test the feasibility of interactive components using eye tracking assisted strategy through neurophysiologic evidence. METHODS: HMD implemented with an infrared-based eye tracker was used to generate a virtual environment for VRT. Eighteen healthy subjects participated in our experiment, wherein they performed a saccadic eye exercise (SEE) under two conditions of feedback-on (F-on, visualization of eye position) and feedback-off (F-off, non-visualization of eye position). Eye position was continuously monitored in real time on those two conditions, but this information was not provided to the participants. Electroencephalogram recordings were used to estimate neural dynamics and attention during SEE, in which only valid trials (correct responses) were included in electroencephalogram analysis. RESULTS: SEE accuracy was higher in the F-on than F-off condition (P=0.039). The power spectral density of beta band was higher in the F-on condition on the frontal (P=0.047), central (P=0.042), and occipital areas (P=0.045). Beta–event-related desynchronization was significantly more pronounced in the F-on (–0.19 on frontal and –0.22 on central clusters) than in the F-off condition (0.23 on frontal and 0.05 on central) on preparatory phase (P=0.005 for frontal and P=0.024 for central). In addition, more abundant functional connectivity was revealed under the F-on condition. CONCLUSION: Considering substantial gain may come from goal directed attention and activation of brain-network while performing VRT, our preclinical study from SEE suggests that eye tracking algorithms may work efficiently in vestibular rehabilitation using HMD.

Vestibular Rehabilitation for Patients with Unilateral Peripheral Vestibular Deficit / 대한평형의학회지

Unilateral peripheral vestibular deficit can occur from a different etiology including viral infection, trauma, ear surgery or idiopathic. Patients with sudden unilateral vestibular deficit usually complain of whirling vertigo, postural imbalance and ipsilesional lateropulsion, which gradually recover over a few weeks by vestibular compensation mechanism. Vestibular rehabilitation therapy has been accepted as helpful exercise based training program with strong evidence for acceleration of vestibular compensation in unilateral vestibular deficit. Here the authors described the current issue regarding vestibular rehabilitation in unilateral vestibular hypofunction from the informative literature review.

Rescue of hemodynamic compromise in superior vena cava syndrome with transesophageal echocardiography / 대한마취과학회지

No abstract available.

The Effect of Human Amniotic Membrane, Epidermal Cells and Marrow Mesenchymal Stem Cells in Healing a Skin Defect / 대한정형외과학회잡지

PURPOSE: The purpose of this study was to investigate the transplantation results of human amniotic membrane (HAM), epidermal cells, or marrow mesenchymal stem cells (MSCs) in healing a skin defect. MATERIALS AND METHODS: Defects (full-thickness) in rabbits were treated with HAM alone (group A), HAM injected with cultivated epidermal cells (group B), HAM injected with cultivated MSCs (group C), or Vaseline gauze (group D). Tissue granulation, regeneration, re-epithelization and healing time were measured. Defects and healed area were calculated 2 weeks after surgery. RESULTS: The mean healing area was 67.5%, 81.7%, 83.2% and 49.5% in each group, with all treatment groups significantly different than group D (p<0.01), and groups B and C compared higher than group A (p<0.05). The healing time of groups A, B, and C was 5.7 to 6.4 days faster than that of group D (p<0.01). Histologic analysis showed that the new epidermis covered nearly the whole wound surface in group B and C, and contained granulated tissue with fibroblasts, capillaries, and collagen. CONCLUSION: HAM grafts injected with cultivated epidermal cells or MSCs promoted healing of skin defects.

Arthroscopic Internal Fixation of Displaced Tibial EminenceFracture Using Cannulated Screw / 대한정형외과학회잡지

PURPOSE: This study examined the outcome of arthroscopic internal fixation for types II and III tibial eminence fractures in children using a cannulated screw. MATERIALS AND METHODS: A series of 10 cases of displaced fractures of tibial eminence of the tibia that were treated with an arthroscopic cannulated screw fixation from February, 1997 to October, 2005 were examined. Four patients had a type II and six patients had a type III tibial eminence fracture according to the Meyer and McKeever's classification. All the patients were reviewed radiographically and clinically for bone union, instability and the range of motion after an average follow-up of 22.4 months (range, 12 to 81 months). RESULTS: There were no cases of nonunion. The clinical examination showed that, all the patients with types II and III lesions had a negative Lachman test, and a full range of motion with the exception of one patient with a type III fracture. The average Lysholm functional score was 96.3 (mim 92.6-max 99.0) for all types II and III lesions. CONCLUSION: Arthroscopic internal fixation with a cannulated screw for types II and III avulsion fractures of the tibial eminence in children can provide a satisfactory outcome through firm fixation of the fragment and an early start of the range of motion.

Costoclavicular Syndrome: A Case Report

Costoclavicular syndrome is one of the four syndromes of thoracic outlet syndrome in which have similiar symptoms, and may result from cervical and thoracic scoliosis, formation of excessive callus or nonunion after fractures of clavicle or first rib. Conservative treatment may be offered. Surgical treatment includes scalenectomy with supraclavicular approach, transaxillary first rib resection with scalenectomy and correction of clavicular abnormality. The purpose of this paper is to evaluate the result of surgical intervention in costoclavicular syndrome of a 38-year old man with clavicular nonunion after an operation.

Metal Failure of Pedicle Screw System / 대한척추외과학회지

STUDY DESIGN: The metal failure of pedicle screw system followed by posterolateral or posterior fusion used in variable cases(spine fracture, degenerative disorder of spine, deformity of spine) was analyzed retrospectively. PURPOSE: The goal of this study was to analyze frequency and clinical consequence of pedicle screw fixation system failure in the treatment of different etiology(spine fracture, degenerative disorder, deformity of spine) and to evaluate affected factors in metal failure. MATERIALS AND METHODS: We performed survivorship analysis on 442 patients treated with pedicle screw system from September 1990 to December 1999. The average follow-up period was 54 months(from 18 months to 129 months). As affected factors, some variables such as etiology, kinds of system and extent of fusion were subjected to analyzed their influence on metal failure. We also performed analysis about relationship between metal failure and clinical results. We defined the metal failure as 1) breakage of screw or rod 2) screw bending above 5 degrees 3) dissociation of rod-screw coupling system and 4) screw pull out from vertebral body or pedicle. RESULTS: We found out 33 cases of metal failure: among 2786 screws, 41 screws had a problem. The metal failure rate was different between each etiology ; 12 cases in fracture(10%), 21 cases in degenerative disorder(6.9%). There was also difference between a kinds of implants; 13 cases in side assembling type(5.4%), 20 cases in back open type(10.5%). However, there were no difference according to extent of fusion; 6 cases in one segment(6.9%), 21 cases in two segments(8.1%), 6 cases in more than three segments(6.3%). Among the overall patients with metal failure (33 cases), only eight patients were complaint significant symptoms. And three of this eight patients were improved after reoperation The mean interval to metal failure was 14.4 months from operation. CONCLUSION: The metal failure was more common in spine fracture(p0.05). And metal failure did not significantly affect the clinical results(p>0.05).