The risk of cataractogenesis after gamma knife radiosurgery: a nationwide population based case-control study.

BACKGROUND: Medical radiation is considered a factor responsible for cataractogenesis. However, the incidence of this ophthalmologic complication resulting from gamma knife radiosurgery (GKRS) has not yet been reported. The present study aimed to determine the risk of cataractogenesis associated with radiation exposure from GKRS. METHODS: This study used information from a random sample of one million persons enrolled in the nationally representative Taiwan National Health Insurance Research Database. The GK group consisted of patients who underwent GKRS between 2000 and 2009. The non-GK group was composed of subjects who had never undergone GKRS, but who were matched with the case group for time of enrollment, age, sex, history of coronary artery disease, hypertension, and diabetes. RESULTS: There were 277 patients in the GK group and 2770 matched subjects in the non-GK group. The GK group had a higher overall incidence of cataracts (10.11% vs. 7.26%; crude hazard ratio [cHR], 1.59; 95% CI, 1.07-2.36; adjusted hazard ratio [aHR], 1.25; 95% CI, 0.82-1.90) than the non-GK group. Patients who had undergone computed tomography and/or cerebral angiography (CT/angio) studies had a higher risk of developing cataracts than those who did not (10.82% vs. 6.64%; cHR, 1.74; 95% CI, 1.31-2.30; aHR, 1.65; 95% CI, 1.22-2.23). The age group between 30 and 50 years had the highest risk of cataractogenesis in both the GK and CT/angio groups (cHR, 3.50; 95% CI, 1.58-7.72; aHR, 2.43; 95% CI, 1.02-5.81; cHR, 2.96; 95% CI, 1.47-5.99; aHR, 2.27; 95% CI, 1.05-4.93, respectively). CONCLUSIONS: Radiation exposure due to GKRS and CT/angio study may be independently associated with increased risk of cataractogenesis. We suggest routine dosimetry measurement of eye lens and proper protection for patients with benign lesions during GKRS. Regular follow-up imaging studies should avoid the use of CT/angio, and particular care should be taken in the 30-50-year-old age group, due to their significantly increased risk of cataract formation.

Subconjunctival Injection of Fluconazole in the Treatment of Fungal Alternaria Keratitis.

PURPOSE: We report two cases of Alternaria keratitis refractory to the conventional antifungal medical treatment successfully treated with subconjunctival fluconazole injection. METHODS: Report of two cases. RESULTS: After subconjunctival injection of fluconazole (2 mg/mL) 0.5 mL twice a day for 5 days then once a day till 14 days, two cases of Alternaria keratitis refractory to the conventional antifungal medical treatment were successfully treated. No severe local and systemic side effects were found in these two patients. CONCLUSIONS: Alternaria keratitis has a varied clinical presentation and suspicion must be maintained for unusual causes of infectious keratitis. Alternaria keratitis can be difficult to eradicate even with traditional antifungals such as amphotericin B and natamycin. Subconjunctival injection of fluconazole could be effective for Alternaria keratitis unresponsive to conventional antifungal medical treatment.

Neuroprotective synergy of N-methyl-D-aspartate receptor antagonist (MK801) and protein synthesis inhibitor (cycloheximide) on spinal cord ischemia-reperfusion injury in rats.

Thoraco-abdominal aortic surgery requiring temporal cross clamping of the aorta results in a high incidence of paraplegia due to temporary ischemia of the spinal cord. Both excitotoxicity and apoptosis are implicated in the pathogenesis of spinal cord ischemia-reperfusion injury. We propose that the N-methyl-D-aspartate receptor antagonist dizocilpine maleate (MK801) and the protein synthesis inhibitor cycloheximide produce a synergic effect in a rodent model of spinal cord ischemia-reperfusion injury. Injury was induced by 20 min of temporal thoracic aorta occlusion and distal blood volume reduction. After injury, the animals were treated with vehicle, MK801, cycloheximide or MK801 and cycloheximide. Hind limb motor function recovery was better in the MK801 and combined therapy groups than in the control and cycloheximide groups. The mean neuronal survival rate of the control group was 45.3 +/- 3.2% on the 7(th) day after injury. In the MK801 and cycloheximide treatment groups, neuronal survival increased to 62.4 +/- 3.6% and 54.1 +/- 2.4%, respectively. For the combined therapy group, neuronal survival increased to 75.6 +/- 2.5%. The number of apoptotic cells in the control group was 211.4 +/- 8.8 per section on the 7th day after ischemic insult, while apoptosis was significantly reduced in the cycloheximide (96.8 +/- 6.7 cells) and combined (84.8 +/- 8.5 cells) groups. It was unchanged in the MK801 group (209.8 +/- 5.4 cells). These results suggest that combined treatments directed at blocking both N-methyl-D-aspartate receptor-mediated excitotoxic necrosis and caspase-mediated apoptosis might have synergic therapeutic potential in reducing spinal cord ischemia-reperfusion injury.

Nuclear factor-kappaB-regulated cyclooxygenase-2 expression in surgery-associated paraspinal muscle injury in rats.

OBJECT: Paraspinal muscle injury is a common but neglected complication of posterior spinal surgery. Evidence suggests that surgical retraction places mechanical and oxidative stress on the paraspinal muscles and that inflammation is a major postoperative pathological finding in the muscles. The roles of cyclooxygenase (COX)-2 and nuclear factor (NF)-kappaB in the inflammatory processes after retraction remain to be clarified. METHODS: In the control group, paraspinal muscles were dissected from the spine via a posterior incision and then laterally retracted. Paraspinal muscle specimens were harvested before as well as at designated time points during and after persistent retraction. The time course of NF-kappaB activation was determined by gel shift assay. Expression of COX-2 was examined using Western blot analysis and immunohistochemistry. The severity of inflammation was evaluated based on histopathology and myeloperoxidase (MPO) activity. The NF-kappaB activation was inhibited by the administration of pyrrolidine dithiolcarbamate (PDTC) in the PDTC-treated group. Retraction induced early activation of NF-kappaB in paraspinal muscle cells. The expression of COX-2 could not be detected until 1 day postoperativley, reaching a peak at 3 days. The time course of COX-2 expression correlated with that of inflammatory responses and MPO activity. Pretreatment with PDTC inhibited intraoperative NF-kappaB activation and greatly downregulated postoperative COX-2 expression and inflammation in the muscles. Postinflammation fibrosis was also abolished by PDTC administration. CONCLUSIONS: Both NF-kappaB-regulated COX-2 expression and inflammation play an important role in the pathogenesis of surgery-associated paraspinal muscle injury. The therapeutic strategy of NF-kappaB inhibition may be applicable to the prevention of such injury.

Oxidative stress and heat shock protein response in human paraspinal muscles during retraction.

OBJECT: The need for wide dissection and forceful retraction of paraspinal muscles often required for posterolateral lumbar fusion and fixation may severely jeopardize the muscles, structurally and functionally. The underlying pathophysiology of muscle damage may involve both mechanical and ischemic mechanisms. On the other hand, the surgery-related stress may trigger certain protective responses within the insulted paraspinal muscles. This study was conducted to assess the relationship between the oxidative stress and the stress response mediated by heat shock protein 70 (HSP70) induction within paraspinal muscles being retracted. METHODS: Multifidus muscle specimens were surgically obtained before, during, and after retraction in patients with lumbar spondylolisthesis undergoing posterolateral lumbar fusion, pedicle fixation, and laminectomy. Muscle samples were analyzed to determine HSP70 and malondialdehyde (MDA) levels. Both HSP70 expression and MDA production within multifidus muscle cells were increased significantly by retraction. Expression of HSP70 then decreased after a peak at 1.5 hours of retraction, whereas MDA levels remained elevated even after release of retractors for reperfusion of the muscles. Analysis of histopathological and immunohistochemical evidence indicated that the decline of HSP70 synthesis within muscle cells after prolonged retraction was the result of severe muscle damage. CONCLUSIONS: Results of this study highlight the deleterious effect of intraoperative retraction on human paraspinal muscles at the cellular and molecular levels. The authors also found that intraoperative maneuvers aimed at reducing the oxidative stress within the paraspinal muscles may help to attenuate surgery-related paraspinal muscle damage.

Retrobulbar cellular schwannoma. Two cases report and review of the literature.

Cellular schwannoma is a variant of classical schwannoma that is characterized by high cellularity. As it is accompanied by mitotic figures, it is easily mistaken for a malignant neoplasm. However, hyalinized thick-walled blood vessels, an alternating growth pattern of spindle-shaped neoplastic cells, and even Verocay bodies can be found. It is most commonly seen in the paravertebral area, particularly in the mediastinum and retroperitoneum. Retrobulbar cellular schwannoma is uncommon, and only one case has been reported to date. In this study, we report two additional cases of retrobulbar cellular schwannoma that recurred two years after surgery. We suggest that the patient be given an aggressive postoperative treatment because a successful, complete excision cannot be guaranteed at such an anatomic site.

Effects of cultured human adipose-derived stem cells transplantation on rabbit cornea regeneration after alkaline chemical burn.

Ocular chemical burn is a severe injury with poor outcomes. Immediate and appropriate management is highly related to prognosis. We studied the effect of cultured human adipose tissue-derived stem cells on the regeneration of the rabbit cornea after alkaline chemical burn, using used human adipose tissue-derived stem cells as the source material. Immediately after the chemical burn, the experimental eye received a single subconjunctival injection of a stem cell suspension (1.3 × 10(5) cells/0.2 mL), with the other eye serving as control. Rabbits were sacrificed and specimens taken 30 days after injection. The experimental group showed faster wound healing than the control group, and the result for the experimental group was clearer cornea medium. Histologically, there were five to six epithelial cell layers on the corneas of the experimental group as compared to two to three cell layers on the corneas of the control group. Wilcoxon signed rank test showed a significant difference in the epithelial cell layers between the two groups. Surface markers for connexin 43 (Cx43), ß-catenin, E-cadherin, and P63 were analyzed. Cx43 and ß-catenin showed significant change, as determined by the Wilcoxon signed rank test, which indicated good cell renewal during repair of the corneal epithelium damaged by the chemical burn. E-cadherin and P63 showed no significant change during the epithelium healing process. Transplantation of cultured human adipose tissue-derived stem cells as a treatment for a corneal chemical burn promotes cell renewal and assists in damage repair.

Ampullary pyogenic granuloma as a complication of lacrimal plug migration.

We present a patient with ampullary pyogenic granuloma caused by spontaneous migration of a silicone lacrimal plug. A 43-year-old woman with severely dry eyes was treated with non-absorbable silicone punctal plugs insertion in both superior and inferior puncta. Irritation and purulent discharge gradually developed 3 weeks after implantation. A pink, fleshly ampullary lesion over the left superior punctum was noted later. The migrated silicone plug was found close to the common canaliculus during surgery. Histopathologic examination confirmed the diagnosis of pyogenic granuloma. A migrated lacrimal plug resulting in pyogenic granuloma is a rare complication. The treatment of choice is removal of the migrated plug as early as possible. Patients with lacrimal plugs insertions should be informed of possible complications and should be followed up regularly for early detection of plug-related problems.

Eyelid tumors in children: a clinicopathologic study of a 10-year review in southern Taiwan.

PURPOSE: To describe the clinical and histopathologic characteristics of eyelid tumors in children in southern Taiwan. METHODS: Patients younger than 17 years old with histologically confirmed eyelid tumors treated at Chang Gung Memorial Hospital (Kaohsiung) during 1991-2000 were subjected to a retrospective analysis. Patients with inflammation, granulation, hordeolum, chalazion and orbital or conjunctival extension were excluded. RESULTS: Totally, 78 patients (46 boys and 31 girls) with eyelid tumors were included. The 4 most common tumors, in order of frequency, were epidermal cysts (23.1%), dermoid cysts (17.9%), squamous cell papillomas (11.5%), and compound nevi (9%). Recurrence was noted in only 1 case (of a ductal cyst) after surgical excision during the 3-year follow-up period. CONCLUSIONS: Epithelial tumors and dermoid cysts are the most common eyelid tumors of children in southern Taiwan. Surgical excision produced good results. Malignant eyelid tumors are rare in children.

Orbital exenteration for secondary orbital tumors: a series of seven cases.

BACKGROUND: Exenteration is indicated in patients with malignant neoplasms of orbital contents. It entails the removal of the eyeball together with its extraocular muscles and other soft tissues. Exenterations can be classified into (1) total, (2) subtotal, and (3) supertotal exenteration. Retrospectively study, we reviewed 7 patients that had received exenteration/subtotal exenteration with spontaneous granulation/myocutaneous flap implantation or eyelid-sparing exenteration with myocutaneous flap. Primary lesions, histopathological examination results, treatments, and recurrences are discussed. METHODS: A retrospective study of the years 1987 through 2000 disclosed 7 patients that underwent exenteration/subtotal exenteration. The patients ranged in age from 41 to 68 years. Two patients underwent total exenteration without socket augmentation; 4 patients underwent exenteration/ subtotal exenteration with immediate facial reconstruction, and 1 with delayed facial reconstruction. RESULTS: Classification of the 7 patients showed that 2 had basal cell carcinoma of the skin, 2 had squamous cell carcinoma of the conjunctiva, 1 had squamous cell carcinoma of the paranasal sinus, 1 had rhabdomyosarcoma of the paranasal sinus, and 1 had intracranial meningioma. Radiotherapy was performed in 6 of the patients and chemotherapy in 2. Central nerve system invasion was noted in 2 patients, and 1 died due to it. CONCLUSION: Secondary orbital tumors involved the orbit from adjacent tissues: paranasal sinuses, nasopharynx, lacrimal sac, conjunctiva, eyelid, intraocular tissue, and intracranial tissues. Combined surgeries are necessary for complete tumor removal. And the imaging studies should include the field of the orbit, sinus, and brain to search for the primary lesions.

Outer table craniotomy for frontal sinus mucocele.

Variants of the external osteoplastic flap procedure or endoscopy have been used to approach the frontal sinus mucocele. The authors introduce a modified external approach for radical resection of the mucocele. Using the bicoronal skin incision, the skin flap exposed the right upper orbital rim. The outer table craniotomy was then performed to expose the frontal sinus cavity while carefully preserving the inner table, with radical removal of the mucocele mucosa. The sinus cavity was irrigated with hyper-oxide solution to ensure adequate destruction of possible residual mucosa. The fascia of the frontalis muscle was split, with one part placed into the mucocele cavity to plug the nasofrontal duct. The advantages of the procedures for mucocele removal include clear visualization of the frontal sinus for radical resection of the mucosa, preservation of the inner table avoiding dura manipulation, prevention of central nervous system infection, possibly lower rates of recurrence, prevention of mucosal ingrowth by plugging of the nasofrontal ducts with fascia, and favorable cosmetic outcome. The disadvantages are more intensive surgery comparable to the endoscopic approaches and execution difficulties when the frontal mucocele is small. Additional clinical studies are needed to evaluate the efficiency and safety of this procedure.

Injury severity and cell death mechanisms: effects of concomitant hypovolemic hypotension on spinal cord ischemia-reperfusion in rats.

A number of previous studies indicated that ischemia-reperfusion injury causes two distinct types of cell death--necrosis and apoptosis--in the central nervous system. It was also implicated that the intensity of injury can somehow affect the cell death mechanisms. By occluding the descending thoracic aorta with or without simultaneously induced hypovolemic hypotension in rats, we established a model of experimental spinal cord ischemia-reperfusion (I/R) in which the injury severity can be controlled. Recordings of carotid blood pressure (CBP) and spinal cord blood flow (SCBF) showed that aortic occlusion induced dramatic CBP elevation but SCBF drop in both the normotensive (NT) and hypotensive (HT) groups of rats. However, the HT group demonstrated significantly lower SCBF during aortic occlusion, and much slower elevation of SCBF after reperfusion, and extremely poor neurological performance. Spinal cord lesions were characterized by infarction associated with extensive necrotic cell death, but little apoptosis and caspase-3 activity. In contrast, in the NT group, I/R injury resulted in minor tissue destruction associated with persistent abundant apoptosis, augmented caspase-3 activity, and favorable functional outcome. The relative sparing of motoneurons in the ventral horns from apoptosis might have accounted for the minor functional impairment in the NT group. The severity of I/R injury was found to have substantial impact on the histopathological changes and cell death mechanisms, which correlate with neurological performance. Our results implicate that injury severity and duration after injury are two critical factors to be considered in therapeutic intervention.