title: Near-infrared (NIR) laparoscopy for intraoperative lymphatic road-mapping and sentinel node identification during definitive surgical resection of early-stage colorectal neoplasia.
abstract: BACKGROUND
  Appropriate lymphatic assessment is a cornerstone of definitive surgical resection for colorectal cancer. Near-infrared (NIR) laparoscopy may allow real-time intraoperative identification of territorial lymphatic drainage and sentinel nodes in patients with early-stage disease prior to radical basin resection.
  
  
  METHODS
  With IRB approval and individual consent, consecutive patients with radiologically localized neoplasia underwent peritumoral submucosal injection of indocyanine green (ICG, a fluorophore capable of injection site tattooing and efferent lymphatic migration) prior to standard laparoscopic oncological resection. Intraoperatively, a prototype NIR laparoscope provided both white light and, by switch activation, NIR irradiation with or without discrete spectral back-filtration. Fluorescence identification of sentinel nodes prior to formal specimen dissection allowed their identification for separate histopathological analysis by in situ clipping when found within the specimen or selective lymphadenectomy by "berry-picking" when such nodes lay outside of the standard resection field. Concordance with nonsentinel nodes was then analysed.
  
  
  RESULTS
  Eighteen patients (mean age = 66.4 years [range = 47.9-80.1], mean BMI = 29.1 [range = 20.0-39.9]) were studied. Fourteen had biopsy-proven carcinoma and four had endoscopically unresectable dysplasia. Mesocolic sentinel nodes (mean = 4.1/patient) were rendered obvious by fluorescence either solely within the standard resection field (n = 14) or both within and without the planned field (n = 4) within minutes of dye injection in every case. Laparoscopic ultrasound (n = 5) as well as histopathological analysis demonstrated oncologic correlation of mesocolic sentinel with corresponding territory nonsentinel nodes, correctly confirming the presence of mesocolic disease in 3 patients and the absence of such lymphatic spread in the remaining 15 patients.
  
  
  CONCLUSIONS
  In this study, NIR laparoscopy with ICG mapping allowed ready and rapid confirmation of mesocolic lymphatic drainage patterns and sentinel node identification. With further validation, this technology and technique promises precise, tailored resection surgery by indicating basin pattern and status in advance of radical lymphadenectomy.
authors.affiliation: Department of Colorectal Surgery, Oxford Radcliffe Hospitals, Oxford, UK. cahillra@gmail.com
authors.forename: Ronan A
authors.initials: RA
authors.lastname: Cahill
authors.forename: Mark
authors.initials: M
authors.lastname: Anderson
authors.forename: Lai Mun
authors.initials: LM
authors.lastname: Wang
authors.forename: Ian
authors.initials: I
authors.lastname: Lindsey
authors.forename: Chris
authors.initials: C
authors.lastname: Cunningham
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Mortensen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology / Q000601:surgery*; D004396:Coloring Agents; D005260:Female; D006801:Humans; D007208:Indocyanine Green; D007430:Intraoperative Care / Q000379:methods; D010535:Laparoscopy / Q000379:methods*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D021701:Sentinel Lymph Node Biopsy / Q000379:methods; D013055:Spectrophotometry, Infrared / Q000379:methods; D018084:Ultrasonography, Interventional
chemical_list: D004396:Coloring Agents; D007208:Indocyanine Green