A New Approach to an Old Problem

A patient with progressive visual loss was found to have an optic nerve sheath meningioma. The patient was treated with stereotactic radiotherapy, a computer-guided stereotactic technique that minimizes the risk of radiation-induced optic neuropathy. Six months after treatment, the patient was doing well and showed no signs of radiation-induced optic neuropathy.     

Collagen sponge repair of small cerebrospinal fluid leaks obviates tissue grafts and cerebrospinal fluid diversion after pituitary surgery

OBJECTIVE: Repair of a cerebrospinal fluid (CSF) leak created at the time of transsphenoidal surgery typically involves placement of a fat, fascial, or muscle graft and sellar floor reconstruction. In this report, a simplified repair for small, "weeping" CSF leaks using collagen sponge is described. METHODS: All patients underwent an endonasal transsphenoidal procedure using the operating microscope. At the completion of tumor removal, if a small CSF leak was noted but no obvious large arachnoidal defect was present, a piece of collagen sponge was fashioned to cover the exposed diaphragma sellae. Titanium mesh was then wedged into the intrasellar, extradural space and a larger piece of collagen was placed over the reconstructed sellar floor. Nasal packing was removed within 24 hours. RESULTS: During an 18-month period, 62 consecutive transsphenoidal procedures were performed for tumor removal. Of 20 patients with a small CSF leak (18 pituitary adenomas, 1 Rathke's cleft cyst, and 1 chordoma), all had successful repair with collagen sponge. At follow-up examinations at 1 to 18 months, no patient had required a lumbar drain or had developed meningitis. One other patient had a large intraoperative arachnoidal defect that was unsuccessfully repaired with the collagen sponge technique; in this patient, a second operation was required with a fat graft, sellar floor reconstruction, and lumbar drainage. CONCLUSION: A simplified repair of small CSF leaks after transsphenoidal surgery using a two-layered collagen sponge technique with sellar floor reinforcement is thought to be safe and effective and obviates the need for tissue grafts, fibrin glue, or lumbar drain placement.     

Elevated tricuspid regurgitant jet velocity in subgroups of thalassemia patients: insight into pathophysiology and the effect of splenectomy

A high tricuspid regurgitant jet velocity (TRV) signifies a risk for or established pulmonary hypertension (PH), which is a serious complication in thalassemia patients. The underlying pathophysiology in thalassemia subgroups and potential biomarkers for early detection and monitoring are not well defined, in particular as they relate to spleen removal. To better understand some of these unresolved aspects, we examined 76 thalassemia patients (35 non-transfused), 25 splenectomized non-thalassemia patients (15 with hereditary spherocytosis), and 12 healthy controls. An elevated TRV (>2.5 m/s) was found in 25/76 (33 %) of the patients, confined to non-transfused or those with a late start of transfusions, including patients with hemoglobin H-constant spring, a finding not previously described. These non or late-transfused patients (76 % splenectomized) had significantly increased platelet activation (sCD40L), high platelet count, endothelial activation (endothelin-1), and hemolysis (LDH, plasma-free Hb), while hypercoagulable and inflammatory markers were not significantly increased. The same markers were increased in the seven patients with confirmed PH on cardiac catheterization, suggesting their possible role for screening patients at risk for PH. A combination of hemolysis and absence of spleen is necessary for developing a high TRV, as neither chronic hemolysis in the non-splenectomized thalassemia patients nor splenectomy without hemolysis, in the non-thalassemia patients, resulted in an increase in TRV.     

Postoperative complications associated with 25-gauge pars plana vitrectomy.

BACKGROUND AND OBJECTIVE: To report postoperative complications in eyes undergoing 25-gauge pars plana vitrectomy (PPV). PATIENTS AND METHODS: Seventy consecutive eyes that underwent 25-gauge PPV for various indications, including epiretinal membrane, non-clearing vitreous hemorrhage, and idiopathic macular hole, and had a minimum follow-up of 12 weeks were reviewed retrospectively. Main outcome measures included best-corrected Snellen visual acuity, intraocular pressure (IOP), intraoperative complications, and postoperative complications. RESULTS: The mean visual acuity improved from 20/368 preoperatively to 20/105 postoperatively (P < .00005). Intraoperative complications included retinal tears in 2 eyes (2.9%). Postoperative complications included cataract progression in 17 eyes (42.5%), cystoid macular edema exacerbation in 5 eyes (7.1%), and retinal detachment in 1 eye (1.4%). Postoperative day 1 IOP was statistically lower than preoperative IOP in fluid-filled eyes (P = .031) but not in eyes filled with intravitreal air (P = .30) or gas (P = .52). Sclerotomy sutures were required intraoperatively in 5 eyes (7.1%) and postoperative day 1 hypotony was noted in 4 eyes (5.7%). All of these complications were noted in fluid-filled eyes except for one case of postoperative day 1 hypotony with gas tamponade. CONCLUSIONS: Intraoperative and postoperative complications were rare in this series of 25-gauge PPV. Postoperative cataract progression and hypotony were the most common complications. Fluid-filled eyes appear to have a higher risk of wound leakage and postoperative hypotony after 25-gauge PPV than eyes with air or gas tamponade.     

Pharmacokinetics of an oral drug (acetaminophen) administered at various times in relation to subcutaneous injection of exenatide (exendin-4) in healthy subjects

Exenatide is an incretin mimetic with potential glucoregulatory activity in type 2 diabetes. This randomized, single-blind, placebo-controlled 6-way crossover study assessed exenatide's effect on acetaminophen pharmacokinetics. Of 40 randomized healthy subjects, 39 completed the study. On the placebo day, acetaminophen (1000 mg) was ingested and placebo injected subcutaneously at 0 hours. On exenatide days, acetaminophen was ingested at -1, 0, +1, +2, and +4 hours, relative to the 10 mug exenatide injected subcutaneously at 0 hours. With exenatide injection, mean plasma acetaminophen AUC(0-12 h) values were reduced by 11% to 24% (vs placebo). Peak plasma acetaminophen concentrations were similar for the -1-hour and placebo groups and reduced by 37% to 56% at other times. The most frequent adverse events were generally mild to moderate nausea and vomiting. Exenatide treatment concurrent with or preceding acetaminophen ingestion slowed acetaminophen absorption but had minimal effect on the extent of absorption.