Local recurrence at the site of the Lone Star device through implantation of exfoliated cells during local excision for early rectal cancer:A case report

Introduction: Invasive procedures for colorectal cancer can cause iatrogenic tumor cell seeding. Implantation of these exfoliated cells in the surrounding tissue can result in locoregional cancer recurrence. This has been described in endoscopic procedures and major surgical resections, however recurrence in iatrogenic lesions of the anal canal during minimal invasive rectal surgery has not been shown in literature yet. This is the first reported case of recurrent rectal cancer that developed into an anal metastasis at the site where hooks of the Lone Star Retractor disrupted the epithelial lining of the anal canal during a local excision of early rectal cancer using TAMIS. Presentation of case: A 57 year old male was diagnosed with a high risk early stage rectal adenocarcinoma. He was treated with transanal minimally invasive surgery (TAMIS) with the use of a Lone Star retractor and he received subsequent chemo-radiotherapy. 23 months later the patient developed a bleeding mass bulging out of the anus. A true cut and incision biopsy was performed and the pathology report revealed localization of adenocarcinoma at the anal canal which was similar to the earlier diagnosed rectal carcinoma. The patient underwent an abdominal perineal resection and left-sided lymph node dissection. Discussion and conclusion: This shows that local recurrence through implantation of exfoliated tumor cells can occur in iatrogenic lesions of the anal canal not only in major but also in minimal invasive rectal surgery. Careful tissue handling and rectal washout may reduce the chance of this implantation metastasis.</p

Natural Orbitals and BEC in traps, a diffusion Monte Carlo analysis

We investigate the properties of hard core Bosons in harmonic traps over a wide range of densities. Bose-Einstein condensation is formulated using the one-body Density Matrix (OBDM) which is equally valid at low and high densities. The OBDM is calculated using diffusion Monte Carlo methods and it is diagonalized to obtain the "natural" single particle orbitals and their occupation, including the condensate fraction. At low Boson density, $na^3 < 10^{-5}$, where $n = N/V$ and $a$ is the hard core diameter, the condensate is localized at the center of the trap. As $na^3$ increases, the condensate moves to the edges of the trap. At high density it is localized at the edges of the trap. At $na^3 \leq 10^{-4}$ the Gross-Pitaevskii theory of the condensate describes the whole system within 1%. At $na^3 \approx 10^{-3}$ corrections are 3% to the GP energy but 30% to the Bogoliubov prediction of the condensate depletion. At $na^3 \gtrsim 10^{-2}$, mean field theory fails. At $na^3 \gtrsim 0.1$, the Bosons behave more like a liquid $^4$He droplet than a trapped Boson gas.Comment: 13 pages, 14 figures, submitted Phys. Rev.

Minimally invasive perineal redo surgery for rectovesical and rectovaginal fistulae: A case series

Introduction: Iatrogenic recto-urogenital fistulae are refractory complications that rarely heal without surgical intervention. The ongoing local infection causes pain, discomfort and substantially impacts quality of life. Surgical repair requires adequate exposure and space to fill with healthy tissue, which is a major challenge in pelvic redo surgery. An abdominal approach to repair the fistula is associated with major morbidity and often fails to expose the deep pelvis. In our experience a novel transperineal minimally invasive approach a utilizing single incision laparoscopic surgery (SILS) technique could offer improved results. Presentation of cases: In the present study, three cases of patients with recto-urogenital fistulae after pelvic surgery are described. Two patients were diagnosed with a rectovesical fistula and one patient with a rectovaginal fistula. In all three cases, a minimally invasive perineal approach, using a SILS port, was used to perform surgical repair. The closure of the fistulae involved: a separate repair of the urethra/bladder or vaginal defect and the rectal defect, followed by interposition of vascularized tissue by either a pudendal thigh fasciocutaneous flap or omentoplasty. Discussion and conclusion: This study is the first to report on a minimally invasive perineal approach, utilizing a SILS technique for recto-urogenital fistulae repair after previous pelvic surgery. The current approach improves exposure, creates surgical space, optimizes view and allows the interposition of vascularized tissue, without causing substantial blood loss and avoiding major abdominal surgery