A minimally-invasive rat model of subarachnoid hemorrhage and delayed ischemic injury.

BACKGROUND: Double-injection models of subarachnoid hemorrhage (SAH) in rats are the most effective in producing vasospasm, delayed neurological deficits and infarctions. However, they require two large surgeries to expose the femoral artery and the atlanto-occipital membrane. We have developed a minimally-invasive modification that prevents confounding effects of surgical procedures, leakage of blood from the subarachnoid space and minimizes risk of infection. METHODS: Rats are anesthetized and the ventral tail artery is exposed through a small (5 mm), midline incision, 0.2 mL of blood is taken from the artery and gentle pressure is applied for hemostasis. The rat is flipped prone, and with the head flexed to 90 degrees in a stereotactic frame, a 27G angiocath is advanced in a vertical trajectory, level with the external auditory canals. Upon puncturing the atlanto-occipital membrane, the needle is slowly advanced and observed for cerebrospinal fluid (CSF). A syringe withdraws 0.1 mL of CSF and the blood is injected into the subarachnoid space. The procedure is repeated 24 hours later by re-opening the tail incision. At 8 days, the rats are euthanized and their brains harvested, sectioned, and incubated with triphenyltetrazolium chloride (TTC). RESULTS: Rats develop neurological deficits consistent with vasospasm and infarction as previously described in double-injection models. Cortical and deep infarctions were demonstrated by TTC staining and on histopathology. CONCLUSIONS: A minimally invasive, double-injection rat model of SAH and vasospasm is feasible and produces neurological deficits and infarction. This model can be used to study neuroprotective treatments for vasospasm and delayed neurological deficits following SAH, reducing the confounding effects of surgical interventions.

Lip reconstruction.

Lip reconstruction remains challenging. Accurate analysis of the defect and a thorough understanding of the anatomy and options for reconstruction will maintain the functional and aesthetic quality of this sensitive area.

Microvascular surgery.

LEARNING OBJECTIVES: After reading this article, the participant should be able to: 1. Describe the common room set-up, medical considerations, and technical equipment necessary to perform microvascular surgery. 2. Describe the common arterial and venous techniques in performing microvascular surgery. 3. Recognize the common flap types along with their vascular supply and innervation used for microvascular surgery. 4. Describe common techniques for flap monitoring. 5. Describe techniques and medications for thrombolytic therapy. 6. Describe common medical conditions that may preclude an optimal result in microvascular surgery. SUMMARY: This article will explore common approaches to microsurgery. It is anticipated that the readers can utilize this article for maintenance of certification educational components and take the principles outlined and apply them to their daily practice.