Histology Evaluation of Radiofrequency Ablation

Overview

Trichiasis is a disorder of misdirected eyelashes in which the lashes grow inward towards the eye. Trichiasis can occur as a result of chronic inflammation, infection, such as in herpes or trachoma, trauma, or rare diseases like ocular cicatricial pemphigoid or Stevens-Johnson syndrome. Trichiasis can result significant pain and corneal compromise, ranging from punctate erosions to frank abrasions, as the lashes constantly contact and irritate the ocular surface. Several treatment modalities are available, including mechanical epilation, electroepilation, cryotherapy, laser therapy, and surgical procedures to redirect the lashes. Radiofrequency ablation is a type of electroepilation that utilizes radiowaves to heat and destroy hair follicles. A fine needle is inserted into the follicle and current is applied to destroy the follicle. The needle allows the energy to be focused into the follicle and limits scarring of the surrounding tissues, and the follicles are in theory permanently destroyed in this procedure. Success rates are variable however, ranging from 56 to 90%. Currently, there is no standardized protocol for performing radiofrequency ablation. Many practitioners choose their power settings based on experience, and the Ellman Surgitron machine, a commonly used radiofrequency unit, actually states in their instructions that the power should be titrated based on user experience. In the literature, settings anywhere from 1 to 3 are seen. In this study, our purpose is to examine the effects of different power settings in radiofrequency at the histologic level. The investigators plan to test different power settings on eyelid tissue that would be normally excised and discarded during eyelid correction surgeries. The investigators hope to determine if there is an ideal power setting to achieve hair follicle destruction while minimizing surrounding tissue damage, which could then be used as the standard power setting for radiofrequency ablation of trichiatic lashes in clinical practice. The investigators hypothesize that as power increases, the extent and severity of tissue damage will increase.

Subject fulfilling the inclusion and exclusion criteria and willing to participate in the study will be enrolled. All participants will receive all 4 treatments at the varying power settings (low, 1, 1.5, 2). The patients will be prepped for their surgery in the usual fashion. This portion of the procedure is not experimental and is an elective surgery that the patients are choosing to undergo prior to enrolling in the study. This procedure is performed in the operating room. After adequate anesthesia is achieved, subcutaneous 2% lidocaine with epinephrine with 0.5% marcaine, and vitrase is injected into the lower eyelids and lateral canthal areas. The face is prepped and draped in sterile fashion using topical Betadine. A corneal shield will be placed into the fornix at this time. A lateral canthal incision is then made using a #15 blade. Straight Stevens scissors are used to perform a canthotomy and monopolar cautery was used to incise the inferior crus of the lateral canthal tendon. Hemostasis is maintained. The freed lower eyelid is draped over the zygoma. The excess eyelid is then excised full-thickness with Westcott scissors. (If this excess eyelid skin is at least 5 mm on both sides, the study will be performed and the treatments will be applied at this point). The tissue will be marked and divided into 4 equal sections (2 sections on each lid). Each section will be treated with the designated power setting in the following manner. The probe will be inserted into the follicle under direct visualization to a depth of approximately 1.4 mm. The designated power will be applied for 1 second. All lashes in each segment will be treated. The segments will then be excised and placed into labelled and coded containers of formalin. Attention will then be directed back to completing the lateral tarsal strip/eyelid surgery. The remainder of the surgery will be performed in the usual fashion and is not part of the experimental portion of the study. One 4-0 Vicryl on P-2 needle is then passed through the tarsus backhanded anterior inferiorly exiting posterior superiorly within the wound and then passed back through the periosteum approximately 3 mm from the orbital rim at the level of the superior crus of the lateral canthal tendon and temporarily tied. This procedure is repeated in full on the other side. The sides are compared. Once the proper contour and tightness is achieved, the suture is permanently tied in a horizontal mattress fashion after passing back through the remnants of the inferior crus. Attention is then turned to the upper lid, whose lateral mucocutaneous junction is trimmed using Westcott scissors. The gray lines of the lateral upper and lower eyelids arre reapposed using 6-0 Vicryl. The lateral canthal incisions are closed with a running 6-0 Prolene suture. Tobradex ointment is applied to the eye and eyelid. The patient is awakened and extubated and taken to the recovery room in stable condition. The patients will be examined at their post-operative week 1 and month 1 visits as per the usual standard of care. After the 1 month visit, their participation in the study is complete. The tissue sections will be sent to the pathology department for sectioning and staining. The tissue will be sectioned through the follicles. The slides will be stained with hemotoxylin and eosin and Masson-Trichrome. The extent of tissue damage will be measured as the diameter of abnormal/damaged tissue in microns. The severity will be graded on a numerical scale from 0-3. The results will be compared among the 4 power settings.