Wicking Property of Graft Material Enhanced Bone Regeneration in the Ovariectomized Rat Model

BACKGROUND: Recruitment and homing cells into graft materials from host tissue is crucial for bone regeneration. METHODS: Highly porous, multi-level structural, hydroxyapatite bone void filler (HA-BVF) have been investigated to restore critical size bone defects. The aim was to investigate a feasibility of bone regeneration of synthetic HA-BVF compared to commercial xenograft (Bio-Oss). HA-BVF of 0.7 mm in average diameter was prepared via template coating method. Groups of animals (n = 6) were divided into two with normal (Sham) or induced osteoporotic conditions (Ovx). Subsequently, subdivided into three treated with HA-BVF as an experiment or Bio-Oss as a positive control or no treatment as a negative control (defect). The new bone formation was analyzed by micro-CT and histology. RESULTS: At 4 weeks post-surgery, new bone formation was initiated from all groups. At 8 weeks post-surgery, new bone formation in the HA-BVF groups was greater than Bio-Oss groups. Extraordinarily greater bone regeneration within the Ovx-HA group than Sham-Bio-Oss or Ovx-Bio-Oss group (p<0.05). CONCLUSION: This study suggests that the immediate wicking property of HA-BVF from host tissue activates a natural healing cascade without the addition of exogeneous factors or progenitor cells. HA-BVF may be an effective alternative for repairing bone defects under both normal and osteoporotic bone conditions.

The Reliability and Validity Studies of the Korean Version of the Perceived Stress Scale / 정신신체의학

OBJECTIVES: Perceived stress scale is a self-report inventory to estimate the degree of individual perceived stress in daily life. The aim of this study was to introduce this scale and test the reliability and validity of the Korean version of PSS. METHODS: The total of 154 female hospital workers were included in this study. The survey questionnaires were conducted for demographic information. All participants were required to complete PSS, Hamilton Anxiety scale and Beck Depression Inventory. Reliability and validity studies were conducted and internal consistency was examined. RESULTS: The mean score of the PSS reported in this sample was 20.69+/-4.56. The overall Cronbach's alpha was 0.819, and the test-retest reliability coefficient was 0.66. PSS had a significant positive correlation with the HAM-A(r=0.49, p<0.01), and the BDI(r=0.55, p<0.01). Factor analysis yielded 2 factors with eigenvalues of 3.924 and 2.608, accounting for 65 percent of variance. Factor 1 represented "stress" and factor 2 represented "control of stress". CONCLUSIONS: This study indicates that the PSS is appropriate for estimating the perceived stress levels. These results support the use of PSS in large sections of the population in Korea.

Antielevation Syndrome after Unilateral Anteriorization of the Inferior Oblique Muscle

PURPOSE: To report antielevation syndrome with restriction of elevation on abduction in the operated eye and overaction (OA) of the inferior oblique muscle (IO) of the contralateral eye after unilateral IO anteriorization (AT). METHODS: Medical records were reviewed retrospectively in 8 of 24 patients who underwent unilateral IOAT. Four patients were referred from other hospitals after the same surgery. RESULTS: Four patients had infantile esotropes. The rest showed accommodative esotropia, superior oblique palsy, exotropia, and consecutive exotropia. The mean amount of hyperdeviation was 16.3 PD (10~30). The mean restriction of elevation on abduction in the operated eye was -1.6 (-1~-4) and IOOA of the contralateral eye was +2.7 (+2~+3). IOAT of nonoperated eyes in 4 patients, IO weakening procedure of anteriorized eyes in 2 patients, and IO myectomy on an eye with IOAT in 1 patient were performed. Ocular motility was improved after surgery in all patients. CONCLUSIONS: Unilateral IOAT may result in antielevation syndrome. Therefore bilateral IOAT is recommended to balance antielevation in both eyes. A meticulous caution is needed when performing unilateral IOAT.

Ultrastructural Changes of Myotendinous Nerve Endings following Recession or Resection Procedures of Extraocular Muscle Surgeries in Cats

To verify the postoperative ultrastructural changes of the myotendinous nerve endings of feline extraocular muscles, which are known as proprioceptors. Sixteen recti of four cats were used and divided into three groups. In group A, eight lateral recti were recessed. In group B, four medial recti were resected by 10 mm from insertion to include the myotendinous junction. In group C, four medial recti were resected by 4 mm of muscle bellies only, without disturbing the myotendinous junction. Four weeks after surgery, specimens were examined with electron microscopy. In group A, overall neural structures were well maintained with slight axonal degeneration. In group B, only muscle fibers were observed without any regeneration of neural sprouts. In group C, axonal disintegration and shrinkage were evident. These results indicate that myotendinous nerve endings can be damaged in strabismus surgery, and that resection was more invasive than recession in disrupting myotendinous nerve endings.

Deterioration of Accommodative Esotropia during Part-time Occlusion Therapy

The authors report two cases of suddenly deteriorated accommodative esotropia with amblyopia during part-time occlusion therapy. A 7-year-old girl with right accommodative esotropia, which was well controlled, showed marked increase in esodeviation after part-time occlusion and regained orthophoria without occlusion. This phenomenon was repeated. Recession of both medial recti was performed and orthophoria was well maintained at both distant and near targets. Accommodative esotropia of a 9-year-old boy with glasses also showed a striking increase in esodeviation after part-time occlusion. The authors recommended wearing only glasses without occlusion or surgery and he recovered fusion. Three months later, orthophoria was maintained at distant target, with 8PD esophoria at near target with glasses. Although this complication should be considered before occlusion therapy, it must be taken continuously if needed, because an increase of the deviation size with occlusion may simply reflect a true deviation and may not be a poor prognostic sign.

A Case of Congenital Absence of the Superior Oblique Muscle

PURPOSE: To report a patient with adsence of the superior oblique (SO) muscle of the right eye, who showed improvement after surgery for hyperdeviation and exotropia. METHODS: A four-year-old girl who presented with 14 PD exotropia, and 25 PD hypertropia of the right eye had a history of myectomy of the right inferior oblique (IO) muscle for bilateral SO palsy as a two-year-old. At the time of surgery, severely fibrotic pseudotendon of IO and Tenon's capsule attached to the insertional area of the inferior rectus muscle was found. IO was remyectomized with adhesiolysis. Lateral rectus and superior rectus (SR) muscles were recessed 6.5mm and 7mm, respectively. After exposure of SR, the absence of SO was found. MRI taken at postoperative one day showed definite SO absence. RESULTS: Three weeks after surgery, 4 PD of left hyperphoria at distant and 5 PD of left hyperphoria at near were observed. Right hyperdeviation was not detected. At postoperative 7 months, 4 PD of exophoria, 6 PD of right dissociated vertical deviation (DVD) and 10 PD of left DVD were seen at distant. A small left hyperdeviation was intermittently noted at upgaze and was cautiously followed. CONCLUSIONS: Absence of the superior oblique muscle is rare. However, such absence should be suspected when apparent superior oblique palsy accompanies with severe hyperdeviation and horizontal deviation. MRI or CT is helpful in the diagnosis of this condition and direct confirmation is needed.