title: A new multimodality technique accurately maps the primary lymphatic landing sites of the bladder.
abstract: BACKGROUND
  Pathoanatomic studies have failed to map accurately the primary lymphatic landing sites of the urinary bladder.
  
  
  OBJECTIVE
  To use single-photon emission computed tomography (SPECT) combined with computed tomography (CT) plus intraoperative gamma probe verification to map the primary lymphatic landing sites of the bladder.
  
  
  METHODS
  Clinical trial of 60 consecutive cystectomy patients at a single centre.
  
  
  METHODS
  Flexible cystoscopy-guided injection of technetium nanocolloid into one of six non-tumour-bearing sites of the bladder for preoperative detection of radioactive lymph nodes (LNs) with SPECT/CT followed by intraoperative verification with a gamma probe. Backup extended pelvic LN dissection (PLND) for ex vivo detection of missed LNs.
  
  
  METHODS
  Three-dimensional projection of each LN site.
  
  
  CONCLUSIONS
  A median of 4 (range: 1-14) radioactive LNs were detected per site and patient. Ninety-two percent of all LNs were found distal and caudal to where the ureter crosses the common iliac arteries. Eight percent were found proximal to the uretero-iliac crossing, none without simultaneous detection of additional radioactive LNs within the endopelvic region. Extended PLND resected 92% of all primary lymphatic landing sites; limited PLND resected only 52%. A few LNs may have been missed despite preoperative SPECT/CT, intraoperative gamma probe verification, and extended backup PLND.
  
  
  CONCLUSIONS
  Multimodality SPECT/CT plus intraoperative gamma probe show the template of the bladder's primary lymphatic landing sites to be larger than is often thought. PLND limited to the ventral portion of the external iliac vessels and obturator fossa removes only about 50% of all primary lymphatic landing sites, whereas extended PLND along the major pelvic vessels, including the internal iliac, external iliac, obturator, and common iliac region up to the uretero-iliac crossing, removes about 90%.
authors.affiliation: Department of Urology, University of Bern, 3010 Bern, Switzerland.
authors.forename: Beat
authors.initials: B
authors.lastname: Roth
authors.forename: Michael P
authors.initials: MP
authors.lastname: Wissmeyer
authors.forename: Pascal
authors.initials: P
authors.lastname: Zehnder
authors.forename: Frédéric D
authors.initials: FD
authors.lastname: Birkhäuser
authors.forename: George N
authors.initials: GN
authors.lastname: Thalmann
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Krause
authors.forename: Urs E
authors.initials: UE
authors.lastname: Studer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008207:Lymphatic Metastasis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D001743:Urinary Bladder / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D001749:Urinary Bladder Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery