Faculty Bibliography

Achalasia is a rare condition affecting esophageal motility in children. In a manner similar to the disease found in the adult population, children experience symptoms of dysphagia, regurgitation, and chest pain due to a failure of relaxation of the lower esophageal sphincter. Standard diagnostic approaches include upper endoscopy and esophageal manometry. New developments in diagnosis include high-resolution esophageal manometry and the endoscopic functional lumen imaging probe. Therapies available include endoscopic balloon dilations and botulinum toxin injections into the lower esophageal sphincter, as well as surgical interventions. The Heller myotomy was first described in 1913; since then, there have been many modifications to the procedure to improve outcomes and lower morbidity. Currently, the most commonly performed surgical procedure is the laparoscopic Heller myotomy, in which the sphincter muscle is divided using longitudinal incisions with or without a partial fundoplication procedure. In recent years, per oral endoscopic myotomy (POEM) is gaining support as a viable natural orifice therapy for achalasia. Complications of POEM occur at a relatively low rate, and outcomes following the procedure have been promising. The treatment of end-stage achalasia however, may include partial or total esophagectomy with reconstruction if possible. Future research is focused primarily on increasing the efficacy, and lowering complications, of existing therapeutic modalities.

PURPOSE/OBJECTIVE:For laparoscopic ablation to be successful, accurate placement of the needle to the tumor is essential. Laparoscopic ultrasound is an essential tool to guide needle placement, but the ultrasound image is generally presented separately from the laparoscopic image. We aim to evaluate an augmented reality (AR) system which combines laparoscopic ultrasound image, laparoscope video, and the needle trajectory in a unified view. METHODS:We created a tissue phantom made of gelatin. Artificial tumors represented by plastic spheres were secured in the gelatin at various depths. The top point of the sphere surface was our target, and its 3D coordinates were known. The participants were invited to perform needle placement with and without AR guidance. Once the participant reported that the needle tip had reached the target, the needle tip location was recorded and compared to the ground truth location of the target, and the difference was the target localization error (TLE). The time of the needle placement was also recorded. We further tested the technical feasibility of the AR system in vivo on a 40-kg swine. RESULTS:The AR guidance system was evaluated by two experienced surgeons and two surgical fellows. The users performed needle placement on a total of 26 targets, 13 with AR and 13 without (i.e., the conventional approach). The average TLE for the conventional and the AR approaches was 14.9 mm and 11.1 mm, respectively. The average needle placement time needed for the conventional and AR approaches was 59.4 s and 22.9 s, respectively. For the animal study, ultrasound image and needle trajectory were successfully fused with the laparoscopic video in real time and presented on a single screen for the surgeons. CONCLUSION/CONCLUSIONS:By providing projected needle trajectory, we believe our AR system can assist the surgeon with more efficient and precise needle placement.