Cerebrospinal fluid otorrhea through a congenitally patent fallopian canal.

Cerebrospinal fluid (CSF) otorrhea is a relatively rare entity that may occur either as a spontaneous occurrence or as a result of trauma or surgery. Spontaneous CSF leaks may be found during tympanocentesis, myringotomy, or tube insertion for chronic middle ear effusion. Rapid identification of the problem and timely treatment are required to avoid life-threatening complications such as meningitis. The site of leakage must also be identified so that the disorder can be treated effectively. Computed tomography, magnetic resonance imaging, and radionucleotide localization scanning all play a role in the early identification of the leakage site. A detailed knowledge of possible CSF leakage pathways aids in evaluating imaging studies. We report 2 rare cases of CSF otorrhea through a congenitally patent facial canal and their management.

Intra-operative electrocochleography in stapedectomy and ossicular reconstruction.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of intraoperative electrocochleography (ECOG) in predicating the postoperative hearing improvement in surgery for conductive hearing loss. STUDY DESIGN: This study was a prospective study of 22 patients undergoing intraoperative electrocochleography during a stapedectomy. SETTING: The study was performed in a tertiary referral center. PATIENTS: Intraoperative electrocochleography was performed in 22 patients 27-73 years of age undergoing a stapedectomy for otosclerosis under general anesthesia. INTERVENTION: For each patient, the N1 threshold to click stimulation was measured intraoperatively, before and after the reconstruction. MAIN OUTCOME MEASURES: The intraoperative ECOG thresholds were compared with the pre and postoperative audiograms. RESULTS: Postreconstruction ECOG's demonstrated improvements in the N1 threshold in 19 cases, and were unchanged in 1 case. In each of these cases, improvement in the intraoperative N1 threshold corresponded with improvement in the postoperative audiogram compared with the preoperative studies. In two other cases the postreconstruction ECOG was nearly unobtainable, despite improved hearing postoperatively. CONCLUSION: Intraoperative ECOG appears to be an effective tool for verifying the functional integrity of ossicular reconstructions as in stapedectomies. We speculate that intraoperative ECOG may allow the surgeon to "fine tune" the reconstruction to optimize the hearing results.

Selective cochlear neurectomy for debilitating tinnitus.

Eighth nerve sections have been performed to control debilitating tinnitus, with various success rates (45% to 76%). Patients with a unilateral profound sensorineural hearing loss and disabling tinnitus perceived in that ear are candidates for such surgery. The concept of a selective cochlear neurectomy with preservation of the vestibular nerve is introduced with two case presentations. The indications for surgery, surgical technique, and results are described. Advantages of preserving the vestibular nerve fibers include the lack of postoperative vertigo and disequilibrium and thus a shorter length of hospital stay, and the conservation of a symmetric vestibular input, obviating the lengthy compensation process that might otherwise be needed, particularly in the elderly. A selective cochlear neurectomy for the control of debilitating tinnitus has proven to be successful in controlling tinnitus in the two patients presented, with the added advantage of preservation of their vestibular function. Further controlled studies are necessary to confirm the advantages and effectiveness of this technique.

Dural closure with laser tissue welding.

This study investigates the use of tissue-soldering techniques to substitute or reinforce traditional suture closure of dural incisions. Fresh human cadaveric dura was incised and subsequently closed by use of three techniques: (1) conventional interrupted suture with 4-0 silk (n = 25), (2) laser solder reinforced suture closure (n = 25), and (3) laser solder closure alone (n = 25). Anastomosis tensile strength and hydrostatic leak pressures were measured. Dural repair was also performed in 15 live Lewis rats. Dural closure was accomplished with 9-0 Prolene sutures (n = 5), laser-reinforced suture closure (n = 5), and laser solder closure alone (n = 5). Histologic examination of the closure immediately after soldering and 2 weeks later was performed. Suture closure alone had the lowest leak pressure, 9.4 +/- 1.7 mm Hg, and an intermediate break point, 13.3 +/- 2.1 Kgf/cm2. Measurements with laser solder alone revealed a mean leak pressure of 26.2 +/- 3.7 mm Hg and a break point of 4.6 +/- 1.4 Kgf/cm2. Solder-reinforced suture closure leak pressure measured 64.0 +/- 6.7 mm Hg and 21.4 +/- 2.4 Kgf/cm2. There was a statistically significant increase in leak pressure and tensile strength in the closures performed with laser weld reinforcement of traditional suture technique (p = 0.0001). Dural closure with laser tissue welding alone provided an immediate leak-free closure, but with poor tensile strength. Histologic examination of welded dura and underlying brain tissue showed no evidence of thermal injury in four of five animals studied. Laser welding may significantly decrease the incidence of cerebrospinal fluid leak after dural closure. In addition, laser tissue welding also makes dural closure possible where space constraints make traditional suture closure difficult.

Rotational relaxation of 1,6-diphenylhexatriene in membrane lipids of cells acclimated to high and low growth temperatures.

Measurement of the time-resolved fluorescence depolarization of 1,6-diphenylhexatriene (DPH) in artificial bilayers of microsomal membrane lipids from Tetrahymena gives detailed information concerning the molecular motion of this probe and fluid properties of the membrane lipids which are obscured with steady-state methods. The rotational motion of DPH in these lipids from cells acclimated to 15 and 39.5 degrees C growth temperatures was anisotropic, which agrees with recent time-resolved studies of this probe in synthetic phospholipid systems. Evaluation of DPH polarization data obtained from these lipid fractions at their respective growth temperatures showed differences in physical properties which suggest that "viscosity", per se, of the microsomal lipids is not a strictly regulated as it is in prokaryotic systems. Rotational relaxation of DPH in 39.5 degrees C microsomal lipids measured at 15 degrees C is more complex than that of either lipid fraction measured at its actual growth temperature, suggesting that the probe has partitioned into two dissimilar environments within the bilayer. Similar effects are observed in the microsomes of 39.5 degrees C cells by freeze-fracture electron microscopy following rapid cooling to 15 degrees C. Under these conditions, two distinct regions are observed on the fracture faces, suggesting a correlation between lipid phase changes and alterations in membrane structure.