Tri H. Nguyen

Lookup table–based inverse model for determining optical properties of turbid media

We present a lookup table (LUT)-based inverse model for determining the optical properties of turbid media from steady-state diffuse reflectance spectra that is valid for fiber-based probe geometries with close source-detector separations and tissue with low albedo. The lookup table is based solely on experimental measurements of calibration standards. We used tissue-simulating phantoms to validate the accuracy of the LUT inverse model. Our results show excellent agreement between the expected and extracted values of the optical parameters. In addition, the LUT represents a significant improvement in accuracy at short source-detector separations (300 microm) and low albedo (approximately 0.35). We also present in vivo data from clinically normal and malignant nonmelanoma skin cancers fit to the LUT-based model.

Pilot clinical study for quantitative spectral diagnosis of non-melanoma skin cancer

Several research groups have demonstrated the non‐invasive diagnostic potential of diffuse optical spectroscopy (DOS) and laser‐induced fluorescence (LIF) techniques for early cancer detection. By combining both modalities, one can simultaneously measure quantitative parameters related to the morphology, function and biochemical composition of tissue and use them to diagnose malignancy. The objective of this study was to use a quantitative reflectance/fluorescence spectroscopic technique to determine the optical properties of normal skin and non‐melanoma skin cancers and the ability to accurately classify them. An additional goal was to determine the ability of the technique to differentiate non‐melanoma skin cancers from normal skin.

Design and validation of a clinical instrument for spectral diagnosis of cutaneous malignancy

We report a probe-based portable and clinically compatible instrument for the spectral diagnosis of melanoma and nonmelanoma skin cancers. The instrument combines two modalities--diffuse reflectance and intrinsic fluorescence spectroscopy--to provide complementary information regarding tissue morphology, function, and biochemical composition. The instrument provides a good signal-to-noise ratio for the collected reflectance and laser-induced fluorescence spectra. Validation experiments on tissue phantoms over a physiologically relevant range of albedos (0.35-0.99) demonstrate an accuracy of close to 10% in determining scattering, absorption and fluorescence characteristics. We also demonstrate the ability of our instrument to collect in vivo diffuse reflectance and fluorescence measurements from clinically normal skin, dysplastic nevus, and malignant nonmelanoma skin cancer.

The Use of High Definition Video Modules for Delivery of Informed Consent and Wound Care Education in the Mohs Surgery Unit

The use of video in the informed consent process has been well documented in the literature to improve patient satisfaction, understanding, comprehension, and to decrease anxiety. At the MD Anderson Mohs Surgery Unit, we use high-definition (HD) audiovisual (AV) modules to assist with the delivery of informed consent and to educate patients on the subject of postoperative wound care. The purpose of this work was to develop HD-AV media to inform patients of the risks, benefits, and alternatives of Mohs surgery before they are asked to sign the consent form and to educate patients on basic wound care after Mohs Surgery. The use of a HD virtual surgeon and nurse in the videos educates the patient, allowing the surgeon and nursing staff to attend to other patients within the Mohs Surgery Unit. Using HD digital recording equipment, we captured real-time HD-AV media to explain the risks, alternatives, and benefits of Mohs surgery (surgeon explanation) and to give detailed instructions for postoperative wound care (nurse explanation). Once captured, HD modules were created and stored on a central University of Texas-MD Anderson Cancer Center server in the Texas Medical Center approximately 1 mile from the Mohs Surgery Unit. The full-screen HD modules are accessed on demand at the point of need with the use of standard institutional computers within any of the Mohss centers examination/surgical suites. An early evaluation of this quality improvement initiative was performed to measure patient satisfaction, efficiency, and efficacy of the videos followed by physician/nurse discussion compared with physician/nurse discussion alone. Early evaluation of HD-AV modules used for the delivery of informed consent and postoperative wound care in the MD Anderson Mohs surgery Unit revealed that patient satisfaction was maintained and that this medium was preferred by patients in the video group over physician/nurse discussion alone. The HD modules allowed increased efficiency and patient comprehension, which improved patient education in the Mohs Surgery Unit.

Carbon dioxide laser ablation and adjunctive destruction for Darier-White disease (keratosis follicularis).

An otherwise healthy 31-year-old Caucasian female presented with a diagnosis of Darier’s disease since 11 years of age. She sought treatment to ameliorate the malodorous crusting and recurrent skin infection. On physical examination, keratotic papules coalesced into large macerated, hyperkeratotic plaques that were predominately located in the flexural areas (inframammary area, axilla, and groin). The lesions covered more than 30% to 40% of her total body surface area (Figure 1). She tried medical (isotretinoin, hormone), surgical (Er:YAG laser, CO2 laser, and deep wire-brush dermabrasion), and complementary medical (acupuncture, herbal) therapies with temporary and disappointing results. The details of her treatment and clinical outcome are described in Table 1.

Cross-species identification of genomic drivers of squamous cell carcinoma development across preneoplastic intermediates

Cutaneous squamous cell carcinoma (cuSCC) comprises 15–20% of all skin cancers, accounting for over 700,000 cases in USA annually. Most cuSCC arise in association with a distinct precancerous lesion, the actinic keratosis (AK). To identify potential targets for molecularly targeted chemoprevention, here we perform integrated cross-species genomic analysis of cuSCC development through the preneoplastic AK stage using matched human samples and a solar ultraviolet radiation-driven Hairless mouse model. We identify the major transcriptional drivers of this progression sequence, showing that the key genomic changes in cuSCC development occur in the normal skin to AK transition. Our data validate the use of this ultraviolet radiation-driven mouse cuSCC model for cross-species analysis and demonstrate that cuSCC bears deep molecular similarities to multiple carcinogen-driven SCCs from diverse sites, suggesting that cuSCC may serve as an effective, accessible model for multiple SCC types and that common treatment and prevention strategies may be feasible.

Paramedian forehead flap: advances, procedural nuances, and variations in technique.

BACKGROUND The paramedian forehead flap (PFF) is a well-established technique for reconstruction of large nasal defects. The literature has provided several technical advances and procedural nuances that expand the surgeons options when performing this procedure. OBJECTIVE The objective is to provide procedural nuances, technical tips, and suggestions for improving flap outcomes. Specific techniques such as extending flap length below the orbital rim, avoiding terminal scalp hair inclusion in the flap design, restoring lining to full-thickness defects, and even flap dressings and wound care are detailed here. Of particular importance, the 3-staged turnover forehead flap for wounds requiring nasal lining, with delayed flap sculpting and cartilage graft placement, has revolutionized the conceptual approach to the most complicated nasal defects, and the technique is described in detail. METHODS This article includes the techniques and approaches from 3 different surgeons at 3 different institutions with 3 different training backgrounds, in an effort to provide a nuanced and broad overview of the subject matter. RESULTS AND CONCLUSION The PFF technique has been refined with increasing procedural variations and nuances in technique. The nasal reconstructive surgeon, armed with knowledge of these techniques, can approach each patient with a broad knowledge base and perform reconstruction with maximum success.

Association Between Type of Reconstruction After Mohs Micrographic Surgery and Surgeon-, Patient-, and Tumor-Specific Features: A Cross-Sectional Study

BACKGROUND There are few data to indicate whether the type of final wound defect is associated with the type of post‐Mohs repair. OBJECTIVE To determine the methods of reconstruction that Mohs surgeons typically select and, secondarily, to assess the association between the method and the number of stages, tumor type, anatomic location, and patient and surgeon characteristics. METHODS Statistical analysis of procedure logs of 20 representative young to mid‐career Mohs surgeons. RESULTS The number of stages associated with various repairs were different (analysis of variance, p < .001.). Linear repairs, associated with the fewest stages (1.5), were used most commonly (43–55% of defects). Primary repairs were used for 20.2% to 35.3% of defects of the nose, eyelids, ears, and lips. Local flaps were performed typically after two stages of Mohs surgery (range 1.98–2.06). Referral for repair and skin grafts were associated with cases with more stages (2.16 and 2.17 stages, respectively). Experienced surgeons were nominally more likely perform flaps than grafts. Regression analyses did not indicate any association between patient sex and closure type (p = .99) or practice location and closure type (p = .99). CONCLUSIONS Most post‐Mohs closures are linear repairs, with more bilayered linear repairs more likely at certain anatomic sites and after a larger number of stages.

Precautions with gentian violet: Skin marking made sterile, effective, and economical

BACKGROUND Surgical site infections have been caused by gentian violet (GV) marking solutions that were contaminated with Mycobaterium chelonae. GV solution is also used in surgery to mark surgical sites. It is commercially available as a solution that may not have been prepared under sterile conditions. OBJECTIVE Our objective is to describe a skin marking method that is sterile, effective, and economical. METHODS GV solution; microcentrifuge tubes; and round, wood toothpicks are used as an alternative to the standard surgical marker. GV (4 drops) is dispensed into a microcentrifuge tube. After capping, the tube is autoclaved. The toothpick is used as the writing instrument and dipped into the GV as needed for intraoperative skin marking. Unlike commercially available skin markers, skin moisture will not cause the writing implement (toothpick) to become ineffective; merely dry the skin before skin marking. RESULTS Autoclaving the commercially available shelved GV solution ensures sterility. The cost of the GV, toothpicks, and microcentrifuge tubes is approximately

The banana: a surgery training model to refine blade control for Mohs layer removal and skin incisions.

0.10 per operation. In contrast, commercially available surgical markers range in cost from