Anesthesia in Dermatologic Surgery

Local anesthetics work by inhibiting conduction along peripheral nerves. The most commonly used one is lidocaine. Anesthetics can be mixed with epinephrine when appropriate to produce a local vasoconstriction that decreases its systemic absorption and bleeding. Nerve blocks are classified into ring blocks and peripheral nerve blocks. Both these blocks require the ability to locate anatomical landmarks and to infiltrate with the proper technique to ensure blockade of pain sensation

Histopathology Laboratory Setup and Necessary Instrumentation

A well-prepared and smoothly running office and lab are very important to performing successful Mohs micrographic surgery. The medical office of a Mohs surgeon is unique compared to most other medical offices in the sense that throughout the day, patients move frequently between the operating room and the surgical waiting room. While this is occurring, tissue specimens are being carried between the operating room, histopathology laboratory, and the microscope. It is necessary to have a well- equipped operating room, a comfortable waiting area, a laboratory to process the tissue specimens, an area for histopathology slide reading, and a space to clean and sterilize instruments properly. As each area of the office is discussed, equipment pertinent to that area will be addressed

Mohs Micrographic Surgery for the Eyelid

The eyelid protects the eye from environmental insults and assists in keeping the cornea moist. At only 0.6 mm thick, the periorbital skin is one of the thinnest cutaneous surfaces of the body. Mohs micrographic surgery (MMS) offers advantages over other resection techniques for this area because it attempts to conserve tissue and preserve function. A thorough understanding of the anatomy of this area is paramount to avoid permanently damaging vital structures. The patient’s eye must be protected at all times. Basal cell carcinoma (BCC) is the most common malignancy in the periorbital region and accounts for 90–95% of all periorbital malignancies. Although BCCs are not likely to metastasize, they can locally grow to destroy the eye, orbit, nose, and sinuses. A number of histologic subtypes of periorbital BCCs are associated with a higher likelihood of recurrence including: multicentric, desmoplastic, basosquamous, keratotic, morpheaform, and micronodular. Dr. Mohs published the largest series using Mohs micrographic surgery (MMS) to treat periorbital BCC, and out of 1,124 cases of primary BCC and 290 recurrent BCCs, the 5-year cure rates were 99.4% and 92.4%, respectively! The second most common periorbital malignancy is squamous cell carcinoma (SCC), accounting for approximately 5–10% of all periorbital malignancies. Similar to BCC, SCC presents more commonly on the lower eyelid but not to the same extent as BCC. Unlike periorbital BCC, the metastatic rates of periorbital SCC have been reported to be as high as 21%. Unfortunately, SCC of the eyelid is much more likely to recur and metastasize when compared to other anatomical locations

Optical coherence tomography for assessment of epithelialization in a human ex vivo wound model

The ex vivo human skin wound model is a widely accepted model to study wound epithelialization. Due to a lack of animal models that fully replicate human conditions, the ex vivo model is a valuable tool to study mechanisms of wound reepithelialization, as well as for preclinical testing of novel therapeutics. The current standard for assessment of wound healing in this model is histomorphometric analysis, which is labor intensive, time consuming, and requires multiple biological and technical replicates in addition to assessment of different time points. Optical coherence tomography (OCT) is an emerging noninvasive imaging technology originally developed for noninvasive retinal scans that avoids the deleterious effects of tissue processing. This study investigated OCT as a novel method for assessing reepithelialization in the human ex vivo wound model. Excisional ex vivo wounds were created, maintained at air-liquid interface, and healing progression was assessed at days 4 and 7 with OCT and histology. OCT provided adequate resolution to identify the epidermis, the papillary and reticular dermis, and importantly, migrating epithelium in the wound bed. We have deployed OCT as a noninvasive tool to produce, longitudinal "optical biopsies" of ex vivo human wound healing process, and we established an optimal quantification method of re-epithelialization based on en face OCT images of the total wound area. Pairwise statistical analysis of OCT and histology based quantifications for the rate of epithelialization have shown the feasibility and superiority of OCT technology for noninvasive monitoring of human wound epithelialization. Furthermore, we have utilized OCT to evaluate therapeutic potential of allogeneic adipose stem cells revealing their ability to promote reepithelialization in human ex vivo wounds. OCT technology is promising for its applications in wound healing and evaluation of novel therapeutics in both the laboratory and the clinical settings