Faculty Bibliography

Pathologic processes involving the urachus are usually related to inflammatory or sinofistular conditions. Neoplasms rarely arise within this structure, and when they do occur, they are typically epithelial, with mucinous adenocarcinoma being the most common. Mesenchymal lesions, both benign and malignant, have rarely been described in this location. We report the case of a 66-year-old white man who presented with a primary urachal malignant fibrous histiocytoma and died of metastatic disease 20 months after the initial diagnosis. This is an unusual case of malignant fibrous histiocytoma arising in a urachal remnant

OBJECTIVES: To study complications of powered intracapsular tonsillectomy and adenoidectomy (PITA) in pediatric patients with obstructive sleep apnea (OSA). STUDY DESIGN: Retrospective chart review and long-term follow-up in office or by telephone interview. METHODS: We studied 278 patients who underwent PITA between September 2000 and October 2002. Outcome measures were postoperative bleeding, velopharyngeal insufficiency, need for hospital readmission, tonsil regrowth, and return of snoring or sleep apnea symptoms. RESULTS: All 278 children treated by PITA had immediate resolution of symptoms of OSA. Complications were noted in 11 patients (3.9%). Nine patients (3.2%) experienced tonsil regrowth with snoring, two of whom evolved to a return of OSA that was definitively managed by means of a complete tonsillectomy. Two patients (0.7%) had self-limited bleeding. None of the patients developed persistent velopharyngeal insufficiency or required hospital readmission. CONCLUSIONS: Microdebrider-assisted PITA is a safe and effective alternative for children otherwise treated with traditional tonsillectomy for symptoms of OSA due to adenotonsillar hypertrophy. This series suggests a 3.9% overall rate of complications, with the most common noted as tonsillar regrowth without recurrence of OSA. Prospective trials with longer follow-up may define higher complication rates

Voltage-dependent membrane conductances support specific neurophysiological properties. To investigate the mechanisms of coincidence detection, we activated gerbil medial superior olivary (MSO) neurons with dynamic current-clamp stimuli in vitro. Spike-triggered reverse-correlation analysis for injected current was used to evaluate the integration of subthreshold noisy signals. Consistent with previous reports, the partial blockade of low-threshold potassium channels (I(KLT)) reduced coincidence detection by slowing the rise of current needed on average to evoke a spike. However, two factors point toward the involvement of a second mechanism. First, the reverse correlation currents revealed that spike generation was associated with a preceding hyperpolarization. Second, rebound action potentials are 45% larger compared to depolarization-evoked spikes in the presence of an I(KLT) antagonist. These observations suggest that the sodium current (I(Na)) was substantially inactivated at rest. To test this idea, I(Na) was enhanced by increasing extracellular sodium concentration. This manipulation reduced coincidence detection, as reflected by slower spike-triggering current, and diminished the hyperpolarization phase in the reverse-correlation currents. As expected, a small outward bias current decreased the pre-spike hyperpolarization phase, and TTX blockade of I(Na) nearly eliminated the hyperpolarization phase in the reverse correlation current. A computer model including Hodgkin-Huxley type conductances for spike generation and for I(KLT) showed reduction in coincidence detection when I(KLT) was reduced or when I(Na) was increased. We hypothesize that desirable synaptic signals first remove some inactivation of I(Na) and reduce activation of I(KLT) to create a brief temporal window for coincidence detection of subthreshold noisy signals

BACKGROUND: Oncologic resection of the maxilla requires management of the nasolacrimal sac/duct system (NLS). A variety of techniques may be used: simple transection, transection with transcanalicular stenting, drilling of the entire nasolacrimal bony canal to the inferior meatus with mobilization of an intact NLS, marsupialization of the NLS with or without stenting, and simple transection with routine delayed dacryocystorhinostomy (DCR) for symptomatic epiphora. Rates of prolonged epiphora range from 13 to 63%. OBJECTIVES: We present our approach to NLS management during maxillectomy, and our rates of epiphora. STUDY DESIGN: Review of 212 consecutive patients who underwent transection of the NLS during medial maxillectomy, complete maxillectomy with preservation of orbital contents, suprastructure maxillectomy, or maxillectomy as part of anterior craniofacial resection. Patients with primary NLS tumors were excluded. Prolonged epiphora is defined as persistent if it lasts more than 6 months. METHODS: After exposure of the anterior maxillary wall and inferior and medial orbital rim, a high-speed drill and Kerrison rongeurs are used to remove the anterior wall of the nasolacrimal canal. The NLS is transected 12-15 mm distal to the periorbita and removed from the canal. Two 4-6-mm opposing incisions are made at the distal duct. Two semicircular flaps are everted, folded, and sutured to the proximal sac or periorbita. A transcanalicular stent is not placed. RESULTS: Two-hundred twelve patients underwent the above-mentioned procedure. Four patients (1.9%) developed prolonged epiphora, which required delayed DCR. CONCLUSIONS: Marsupialization of the NLS without stenting provided us with an acceptably low rate of prolonged epiphora