The effects of tetanus toxin on the orbicularis oculi muscle

PURPOSE: Tetanus toxin can cause localized neuromuscular weakness, but it also can produce systemic tetany. The action of tetanus toxin on the orbicularis muscle has not been studied in animals immunized to prevent systemic tetany. Our objective was to determine whether tetanus toxin could be used to treat orbicularis oculi muscle spasms. METHODS: We analyzed the clinical, electrophysiologic, and histopathologic effects of tetanus toxin injected into the orbicularis oculi muscle of rabbits with passive immunity to tetanus toxin. In six rabbits, the orbicularis oculi function in both eyes was assessed clinically, and the baseline orbicularis oculi muscle action potential was measured physiologically with electromyography (EMG). The rabbits then were immunized against tetanus toxin with tetanus immunoglobulin for immediate and definitive immunity. Tetanus toxin was injected into the left orbicularis oculi muscles, leaving the right eyes as controls. Ten days later, the rabbits were again assessed by clinical examination and with EMGs on both the injected side and the noninjected side. The animals were killed at 14 days, and the orbicularis muscle was removed from both sides. The injected and control tissues were examined microscopically for signs of neuromuscular denervation. RESULTS: All six rabbits showed weakness in eye closure on the side injected with tetanus toxin. In addition, four rabbits developed complete ear ptosis on the tetanus toxin injected side because of spread of the toxin to adjacent ear muscles. EMGs showed both a denervation of the orbicularis oculi muscle and a poor blink potential on the side injected with tetanus toxin. Histopathologic studies of the orbicularis oculi muscle injected with tetanus toxin showed angulation of both slow and fast types of muscle fibers compatible with neuromuscular denervation. CONCLUSIONS: Tetanus toxin can cause localized orbicularis oculi weakness, as documented clinically, physiologically, and microscopically, without producing systemic tetany in immunized rabbits. Tetanus toxin may have a potential application in the treatment of blepharospasm and hemifacial spasm.     

External pneumatic compression does not increase urokinase plasminogen activator after abdominal surgery

External pneumatic compression (EPC) devices prevent lower extremity deep venous thrombosis (DVT) by reducing stasis. There is a widely held belief that they also enhance endogenous fibrinolysis; however, recent studies of tissue plasminogen activator (the primary activator of fibrinolysis) and plasminogen activator inhibitor-1 (the primary inhibitor of fibrinolysis) failed to confirm this. The hypothesis of this study was that EPC devices increase the level of urokinase plasminogen activator (uPA), a second activator of fibrinolysis. This was a prospective trial in which 44 subjects who underwent major abdominal surgery were randomized to receive unfractionated heparin injections, thigh-length sequential EPC devices, or both for DVT prophylaxis. Prophylaxis was begun immediately before surgical incision and continued until postoperative day 5 or discharge. Venous blood samples were collected from an antecubital vein for measurement of systemic uPA levels and from the common femoral vein for measurement of regional uPA levels. Samples were collected the day before surgery, after induction of anesthesia but before surgical incision, and on postoperative days 1, 3, and 5. uPA levels (ng/mL) were measured with an enzyme-linked immunoassay. Baseline uPA levels (0.41 to 0.56 ng/mL; P >.05, analysis of variance with repeated measures) were similar among the three groups. uPA levels did not change after surgery in systemic or regional blood samples in any group. There were no significant differences in systemic or regional uPA levels in the groups treated with EPC devices relative to those treated with heparin at any time point (P >.05, analysis of variance with repeated measures). Enhancement of fibrinolysis with EPC devices remains unproven; the findings reported here suggest that effective DVT prophylaxis can only be assured when the devices are used in a manner that reduces venous stasis.     

Benign lymphoid infiltrate of the iris simulating a malignant melanoma

PURPOSE: To report a clinicopathologic correlation of an unusual benign lymphocytic iris mass in a patient who had no systemic lymphoproliferative disease. METHODS: Case report. RESULTS: A 49-year-old man developed a circumscribed, tan lesion in his left iris. The lesion was suspected clinically to be an atypical iris melanoma. Histopathologic studies of the resected mass revealed a solid tumor that was comprised of lymphocytes and histiocytes. Immunohistochemical studies identified that most of the cells were T lymphocytes. The histopathologic diagnosis was atypical lymphoid infiltrate. Workup for systemic lymphoma and Epstein-Barr virus infection was negative. CONCLUSION: Lymphoid infiltrate can manifest as a solitary mass that can simulate an iris melanoma.     

Robotic-assisted adrenalectomy for adrenal incidentaloma: case and review of the technique

An incidental left adrenal mass was found in a patient during an evaluation for mediastinal widening. The patient had no symptoms attributable to adrenal excess. Preoperative biochemical screening was negative for a functioning medullary or cortical adrenal tumor. Surgical resection was successfully completed with the assistance of the da Vinci robotic system. Pathology demonstrated a rare adrenal oncocytoma.     

The evolution of and early experience with robot-assisted mitral valve surgery

Cardiac surgeons have embraced minimally invasive surgery with warranted enthusiasm. The acceleration of technological advances in optics, instrumentation, and cardiopulmonary bypass has allowed safe, effective, efficient minimally invasive cardiac procedures. In this article we review the evolution of and early experience with robot-assisted mitral valve surgery. Articles by leaders in the field of minimally invasive cardiac surgery, both American and European, are reviewed to describe the development of cardiac robotic surgery. The current state of robotic mitral surgery is described.