An Innovative Way of Tumor Localization in Robotic Rectal Cancer Surgery: Using the “FIREFLY” Mode in Da Vinci Xi Robot

Abstract

Introduction: Near infrared technology is used in transplant surgeries, partial nephrectomies, and colorectal surgeries to assess to perfusion at anastomotic sites, identify hidden vessels, and assess blood supply to bowel segments.1–4 The same technology (Firefly) is installed currently on da Vinci Si and Xi robotic systems (Intuitive Surgical, Inc., Sunnyvale). This technology requires ICG (indocyanine green) dye injection. In small rectal tumors which are below the peritoneal reflection and which are difficult/not palpable by digital rectal examination, ensuring a safe distal resection margins while saving maximum rectal stump is difficult. Localizing such tumors with rigid/flexible sigmoidoscope requires dimming/turning off light coming from robotic endoscope, which makes marking the point of transection difficult and unsafe. This video describes a technique to precisely identify the distal trisection point using Firefly mode without the ICG dye, in robotic rectal cancer surgeries. In Firefly mode the entire field is still clearly visible to safely navigate and mark the point of distal transection. Materials and Methods: This is an 18-year-old male patient with a rectal cancer 10 cm above the anal verge. A robotic low anterior resection was performed with splenic flexure mobilization. The distal rectum is dissected until the pelvic floor is reached. Rigid sigmoidoscopy is performed in Firefly mode. The rigid sigmoidoscope is pressed against the anterior wall of the inflated rectum, below the level of tumor and this point of contact shines Firefly green. This point on the rectal wall is marked with methylene blue. This mark acts as a guide for the distal stapler transection once the Firefly mode is discontinued. Results: This method is used in three patients of rectal cancer. All had uneventful postoperative recovery. Final histopathology report showed that two had moderately differentiated adenocarcinoma, whereas one had Signet ring adenocarcinoma. The distal resection margins were clear in all three cases. Conclusion: This technique gives better tumor localization than finger examination or rigid sigmoidoscopy alone when the tumor is small, below the peritoneal reflection, and not easily palpable per anally. With a single switch on the robotic surgeon's console, Firefly mode is switched on. The greenish hue does not limit observation and the light of the sigmoidoscope below the tumor is easily identified. The distal site of transection can be marked without ICG dye and the abdominal dissection remains in clear view. This innovative technique ensures a safe distal resection margin before the stapler is fired while never losing sight of the abdominal dissection. No competing financial interests exist. Runtime of video: 9 mins 58 secs