Tor Chiu

Plasma cell-free DNA as an indicator of severity of injury in burn patients.

Abstract Background: Raised levels of plasma cell-free DNA have been detected in various patient groups, including trauma patients. We hypothesized that plasma DNA is increased in burn patients and may represent an objective indicator of burn severity and have predictive as well as prognostic significance. Methods: This was a prospective clinical study with full ethical approval. With informed consent, blood samples were collected from 28 burn patients within 24h of injury and from 12 control subjects. Plasma cell-free DNA was measured by real-time quantitative polymerase chain reaction (PCR) assay for the β-globin gene. Descriptive analysis, non-parametric data comparison tests (Mann-Whitney) and correlation tests (Spearman rank) were performed on the data. Results: Samples were taken at a mean time of 5.7h after injury from 13 patients with flame/flash burns and 15 patients with scalds. Median plasma DNA levels in the control, scald and flame/flash burn patient groups were 287, 648 and 2685 kilogenome-equivalents/L, respectively. Plasma DNA levels correlated with the length of hospital stay, but not with admission to the intensive care unit (ICU) nor the length of ICU stay. DNA levels correlated with the burn surface area (Spearman rank r=0.54, p=0.04) and the number of operations needed (Spearman rank r=0.55, p=0.03) for scalds, but not for flame/flash burns. Conclusions: Plasma DNA is increased after burn injury and is significantly correlated with some outcome measures, including the length of hospital stay. DNA levels are higher in flame/flash patients than in scald patients; the difference may provide an objective indication of burn depth and inhalation injury.

An Anatomical Study of the Arteries of the Anterior Nasal Septum

OBJECTIVES: The anterior nasal septum is a clinically important area, yet anatomical descriptions of its arterial pattern are hitherto incomplete. This study aimed to test the hypothesis that the arteries of the anterior nasal septum form a fine random network of vessels. STUDY DESIGN: The arterial pattern of the nasal septum was traced by microdissection of 12 cadaveric septa (24 sides). SETTING: Each septum was microdissected with a Watson-Barnet dissecting microscope. Specimens were photographed and the vascular patterns were analyzed. RESULTS: The anterior septum has a consistent large arterial anastomotic triangle receiving major contributions from sphenopalatine, anterior ethmoidal, and superior labial arteries. CONCLUSION: Systematic microdissections clearly demonstrate that the arteries of the anterior septum do not form a random network. Instead, they form a consistent arterial anastomotic triangle consisting of large, thin vessels. SIGNIFICANCE: The study provides background material useful to the understanding of nasal physiology and pathology including epistaxis.

Prospective Clinical Study of Bleeding Sites in Idiopathic Adult Posterior Epistaxis

OBJECTIVES: The precise identification of the bleeding point is important to the efficient management of epistaxis. Our hypothesis was that the septum was the commonest bleeding site. STUDY DESIGN AND SETTING: This was a prospective clinical study of 50 consecutive adult idiopathic posterior epistaxis patients carried out in a busy teaching hospital. METHODS: The nasal cavity was inspected with endoscopy to identify the site of bleeding before any intervention. The location of bleeding sites was recorded on a proforma. RESULTS: Of bleeding sites posterior to the piriform fossa, 94 percent were identifiable, with 70 percent arising from the septum. CONCLUSIONS AND SIGNIFICANCE: This is the largest prospective study of the bleeding site in adult patients with posterior epistaxis and the only one with a well-defined population. The vast majority of posterior bleeding sites can be identified by endoscopy without general anesthesia. The septum should be examined closely in cases of idiopathic bleeding.

Extramammary Paget’s Disease in Chinese Males: A 21-year Experience

BackgroundExtramammary Paget’s disease (EMPD) is a rare disease in Chinese males. Our objectives were to examine the results of our experience, to correlate them with the published literature, and thus to formulate improved management guidelines.MethodsThis was a retrospective analysis of all male patients with EMPD treated at our institution. We reviewed the patients and their case notes for data such as presenting symptoms, delay to diagnosis, incidence of concurrent malignancies, treatments given, and a variety of outcome measures, including the number of patients with recurrent or residual disease.ResultsThe overall recurrence rate was 35%. The risk of recurrence was reduced if intraoperative frozen section analysis was used (25%) compared to simple wide local excision (60%). Wide local excision failed to excise the disease completely in 38%. There were no associated internal malignancies and no disease-related deaths in our sample.ConclusionsWe recommend intraoperative frozen sections to reduce the risk of incomplete resection and to reduce the rate of recurrence. In our population, screening for internal malignancies can be restricted to select patients, e.g., those with perianal disease, those with invasive disease, and young patients.

A validation study of scar vascularity and pigmentation assessment using dermoscopy

INTRODUCTION Vascularity and pigmentation are two important indicators of the maturing status of hypertrophic scars. We used the dermoscope to measure vascularity and pigmentation of hypertrophic scars to examine its validity and reliability. MATERIALS AND METHOD Eighteen subjects were assessed using the Vancouver Scar Scale (VSS), spectrocolorimeter and dermoscope. Correlations between the measurements by these tools and reliability parameters were examined. RESULTS A strong correlation was found between the redness measured by spectrocolorimeter and the RGB redness values of dermoscope pictures (r=0.890). A correlation was found between the lightness measured by spectrocolorimeter and the lightness of dermoscope pictures (r=0.536), and between the lightness by spectrocolorimeter and the blanched dermoscope pictures (r=0.448). The calculated RGB values of redness of the dermoscope correlated with the VSS vascularity score (r=0.625); the transformed VSS pigmentation score correlated with the lightness of the blanched dermoscope pictures (r=0.783). The intra-class correlation coefficient (3, 1) of the dermoscope was 0.980 for the redness measurement and 0.965 for the lightness measurement, while the intra-class correlation coefficient (2, 2) was 0.930 for the dermoscope redness measurement and 0.871 for the dermoscope lightness. CONCLUSION The dermoscope is a promising objective tool for vascularity and pigmentation assessments of hypertrophic scars with good validity and reliability.

Screening Internet websites for educational potential in undergraduate medical education

This paper addresses the difficulty of finding suitable websites to support undergraduate medical students in learning key concepts and skills in plastic surgery in particular, and other areas of undergraduate medical education in general. Based on a model of the pedagogical elements contained in educational websites, the authors developed a short objective scoring system with five criteria. Pre-university students were used to find websites in plastic surgery. One hundred and fifty of those that were still in place after a year were evaluated using the objective scoring system. Sixty of these were then selected and were subjectively evaluated by final year medical students in terms of their perceived educational potential. There was only a moderate correlation between the objective and subjective scores. Our conclusion is that it does not seem possible to construct any objective system of medical website evaluation. The discussion of the results of this study focuses on the issues involved in finding suitable web-based material and the diversity between students. New strategies such as formally organized consortia involving agreements between medical schools may evolve.

Double free flaps for reconstruction of complex/composite defects in head and neck surgery

OBJECTIVE. To demonstrate the feasibility of double free flap surgery in head and neck reconstruction. DESIGN. Descriptive case series. SETTING. A university-affiliated hospital in Hong Kong. PATIENTS. Twelve patients with head and neck cancer (encountered over a 2.5-year period) who had reconstructive surgery with planned simultaneous double free flaps. RESULTS. The mean total operating time was 660 minutes and there were no flap failures. Postoperative stays ranged from 11 to 82 days; nine patients were discharged within 3 weeks and seven were able to maintain their weight with oral feeding. The survival rate up to 1 year was 64%. CONCLUSION. The use of double free flaps is an option worth considering for complex head and neck defects in carefully selected patients.

Urban Temperatures in Hong Kong: Thermal Environmental Safety and Implications for City Planning

Cutaneous thermal injury caused by direct contact with objects heated solely by sun exposure is rare. We undertook to investigate factors that may influence the temperature of sun-exposed objects at the ground level. Two clinical cases of burns caused by contact with sun-exposed objects are described. Surface temperatures on a citywide scale were determined from satellite thermal images. Ground level surface temperatures of a variety of objects were measured using an infrared thermometer. The satellite thermal image demonstrated local surface temperature differences (of more than 10.6°C variation) and the temperature at the places of study (8.5–9.5°C above background). Infrared thermometer readings demonstrated that the surface temperature of a sun-exposed black car could be as high as 75.0°C (range, 71–78°C) compared with 44.6°C (42.2–47.3°C) for a white car, and shading significantly reduced the surface temperatures of exposed objects (10.4–48.1%). The risk of injury is related to the effects of city planning on urban temperatures, of material color, composition, and shade on the ground level temperatures, and to the rise in global temperatures because of greenhouse-induced warming. The combined effect means that in a modern subtropical city such as Hong Kong, a substantial percentage of the urban area may have summertime surface temperatures that are high enough to constitute a health hazard. We recommend that this potential cause of harm to health be taken into account during urban planning.

Surgical anatomy of the distal maxillary artery

Abstract Problem: Arterial ligation of the sphenopalatine artery is a key option in the management of persistent posterior epistaxis. Coexisting with established transantral techniques are newer endoscopic transnasal methods. Knowledge of the arterial configuration allows understanding of the rationale of current treatments and assists in the interpretation of treatment failures. Methods: One hundred twenty-eight cadaveric tissue blocks containing the pterygopalatine fossae were used. One hundred eighteen blocks were dissected using a Watson-Barnet 25× dissecting microscope. Ten blocks were cleared by the Spalteholz technique after injection with latex-Indian Ink. Arterial configurations were analyzed and photographic records were made. Results: Analysis of the arteries in the pterygopalatine fossa showed 3 common configurations: a single looped form (18%) and 2 double-looped forms (51% and 31%). Terminal bifurcation of the sphenopalatine artery arose before the sphenopalatine foramen in 74.6%. In contrast to previous smaller studies, we found remarkable symmetry in the size of the maxillary arteries and a low incidence of “early” pharyngeal arteries. Conclusion: This is the most comprehensive anatomical study of the distal maxillary artery. The arterial configuration can be easily classified into 3 common forms. Some forms are more liable to lead to confusion at the time of ligation particularly if the osteotomy is inadequate. Significance: Understanding of the arterial anatomy and its variants will reduce the risk of technical failures and improve both the rationale and the reliability of ligation procedures in the treatment of epistaxis. Support: None reported.

Use of Intraoperative Indocyanine Green Videoangiography to Guide Cutaneous Angiosarcoma Excision.

Summary: Complete excision of cutaneous angiosarcoma, which is a rare, vascular, and aggressive tumor, is challenging. Its multifocal nature and propensity for lateral spread make the gross assessment of surgical margins difficult. Neither the use of frozen section analysis nor Mohs surgery consistently improves the probability of margin-free excision. Recent studies have advocated the use of indocyanine green to evaluate the vascular system perioperatively. We describe the intraoperative use of indocyanine green to help define the excision margin of a locally extensive scalp angiosarcoma in an elderly man.