Anthropomorphic assessment of the retromolar foramen and retromolar nerve: anomaly or variation of normal anatomy?

The retromolar foramen, retromolar canal, and retromolar nerve constitute a variation of the inferior alveolar nerve (IAN) with a prevalence of 12-75%; this represents type 1 bifidity of the IAN. The aim of this study was to assess the prevalence of the retromolar nerve in our population and to obtain related data. One hundred and thirty-six mandibles of fresh cadavers aged 20-75 years were dissected. The buccolingual location, diameter, and distance from the third molar, and their associations with sex, were measured. The area of innervation and demographic data were also documented and analysed statistically. The retromolar foramen and retromolar nerve were observed in 55 cases (40.4%). The mean diameter of the retromolar foramen was 1.7 mm (range 1.1-2.1 mm); the mean diameter was 1.8 mm in males and 1.5mm in females. Histological findings showed that the retromolar nerve extended from the anterior border of the ramus, innervating the retromolar pad and continuing to the buccal gingiva of up to two teeth anteriorly (first molar region). This high percentage of IAN type 1 bifidity (40.4%) suggests it to be a normal anatomical variation of the IAN rather than an anomaly.

Assessment and outcome of 496 penetrating gastrointestinal warfare injuries.

AIM: The abdominal viscera are among the most vulnerable organs of the body to penetrating trauma. Proper management of such trauma in war victims at the first-line hospital where these victims are first seen is of paramount importance. We reviewed medical records of war victims suffering small bowel and colorectal injuries treated at first, second and third-line hospitals during the Iraq-Iran War (1980-88) to assess surgical outcomes. METHODS: The medical records of 496 Iranian war victims suffering penetrating gastrointestinal (GI) injuries treated at first, second and third-line (tertiary) hospitals, a total of 19 centres, were reviewed. Laparotomy had been performed at the 1st line hospitals for all patients who had an acute abdomen, whose wounds violated the peritoneum or whose abdominal radiographs showed air or shrapnel in the abdominal cavity. Stable patients were transferred from first-line to second-line or from second line to tertiary hospitals postoperatively. The treatments, complications and patient outcomes were documented and analyzed. RESULTS: There were 496 patients; 145, 220 and 131 victims underwent laparotomy for GI injuries at first, second and third-line hospitals respectively. The small intestine and colon respectively were the most prevalent abdominal organs damaged. Those first treated for GI injuries at front-line hospitals (145 victims) had more serious conditions and could not be transferred prior to surgery and presented a higher prevalence of complications and mortality. Overall mortality from GI surgery was 3.6% (18 patients). Eleven patients (7.5%) whose first GI operation was performed at frontline hospitals and 7 patients (3.2%) who underwent their first surgical operation at second-line hospitals died. The most common reason for these deaths was complications relating to the gastrointestinal operation such as anastomotic leak. Six missed injuries were seen at the frontline and one at second line hospitals. There were no deaths at the 3rd line hospitals. CONCLUSION: Penetrating abdominal injuries were common in Iranian victims of war often causing multiple organ injuries. The colon and small intestine were the more commonly injured organs and carried the most postoperative complications. Mortality at 1st line hospitals was more than double that of 2nd line hospitals; the complication rate was also greater as was the number of missed injuries. Adherence to the standard surgical protocols, prompt evaluation, proper triage and management are factors which may lower patient morbidity and complications.

Non-invasive assessment of ocular pharmacokinetics using Confocal Raman Spectroscopy.

A Laser Scanning Confocal Raman Spectroscopy (LSCRS) system was applied for the non-invasive quantification of the transport of a drug through the rabbit cornea in vivo. Employing LSCRS, the changes in the amplitude of a drug-specific Raman signal were assessed over time in the tearfilm and corneal epithelium of the living rabbit eye (n = 6), after topical application of 25 microL Trusopt 2%. This allowed for quantification of pharmacokinetic variables. The effect of the drug on corneal hydration was also monitored. LSCRS demonstrated adequate sensitivity and reproducibility, for continuous real-time monitoring of the Trusopt concentration. Each concentration-time curve had a bi-phasic trend; the rapid initial phase (t<8 min.) corresponds to the nonproductive losses of Trusopt from the tears (k10 = 0.24+/-0.04 min(-1), and the slower later phase (t>20 min.) is the result of transfer of the drug from the corneal epithelium to the stroma (k23 = 0.0047+/-0.0004 min(-1). Drug absorption into the corneal epithelium occurred at a rate of k12 = 0.034+/-0.006 min(-1). Trusopt caused an acute dehydrating effect, with a maximum decrease in corneal hydration of approximately 15% at approximately 60 min. following application of the drug. LSCRS has the specificity, sensitivity, reproducibility and spatial resolution for employment as a potentially valuable tool for the study of ocular pharmacokinetics.

Noninvasive assessment of the hydration gradient across the cornea using confocal Raman spectroscopy.

PURPOSE: The feasibility of Raman spectroscopy for the noninvasive assessment of axial corneal hydration was investigated. METHODS: A scanning confocal Raman spectroscopy system, with an axial resolution of 50 microns, was used to assess noninvasively the water (OH-bond) to protein (CH-bond) ratio as a measure of the hydration in collagen-based phantom media and rabbit corneas. RESULTS: Raman spectra with high signal-to-noise ratios were obtained under in vitro and in vivo conditions within a range of corneal hydration (H = 0.0-8.3 mg water/mg dry wt). The Raman intensity ratio OH/CH showed a strong correlation with the hydration of the phantom medium (R2 > 0.99) and the rabbit corneas (R2 > 0.95). A degree of reproducibility was seen in measurements performed at a specific depth within the cornea (SD = 1.2%-2.7%). Quantitatively, the spatially resolved corneal water content, as assessed with our method, showed an increasing gradient from the anterior to the posterior region, with a difference of approximately 0.9. Significant qualitative differences in the axial hydration gradient were observed between the in vitro and in vivo situation, caused by the presence of an intact tear-film in vivo. Characterization of the axial corneal hydration using Raman spectroscopy provided a reliable estimation of total corneal hydration compared with conventional measurements using pachymetry and lyophilization. CONCLUSIONS: The proposed noninvasive confocal Raman spectroscopic technique has the potential to assess the axial corneal water gradient with a degree of sensitivity and reproducibility.

Dynamics of temperature dependent optical properties of tissue: dependence on thermally induced alteration.

Thermal damage in heated bovine myocardial tissue is assessed from measured changes in total reflection and transmission of light. Mathematical expressions, based on random walk analysis of light propagation within tissue slabs, are used to relate the diffuse reflection and transmittance to the absorption coefficient, mu a, and effective scattering coefficient, mu's, for samples of myocardial tissue which were subjected to rapid step changes in temperature. Time-dependent changes in mu's, indicate two processes, one with a fast and temperature-dependent rate the other with a slow and apparently temperature-independent rate. For final temperatures above 56.8 degrees C and for the first 500 s after the temperature change, the optical parameters are well fit by exponential forms that exhibit temperature-dependent time constants as predicted by Arrhenius reaction rate theory of thermal damage. The scattering changes are associated with an apparent activation energy, delta E, of 162 kJ/mole and a frequency constant, A, of 3 x 10(23) s-1. This method provides a means for estimating optical coefficients which are needed to assess laser tissue dosimetry.