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Impact of radiofrequency energy on intraoperative outcomes of laparoscopic colectomy for cancer in obese patients

Diletta Cassini, Michelangelo Miccini, Matteo Gregori, Farshad Manoochehri, Gianandrea Baldazzi


Nowadays laparoscopic approach is accepted as a valid alternative to open surgery for the treatment of colorectal cancer. Several studies consider this approach to be safe and feasible also in obese patients, even if dissection in these patients may require a longer operative time and involve higher blood loss. To facilitate laparoscopic approach, more difficult in these patients, several energy sources for laparoscopic dissection and sealing, has been adopted recently. The aim of this study is to investigate the possible intraoperative advantages of radiofrequency energy in terms of blood loss and operative time in obese patients undergoing laparoscopic resection for cancer. All patients who underwent laparoscopic surgery for colorectal cancer from January 2010 to December 2015 were registered in a prospective database. Patients with a body mass index BMI (kg/m2) ≥30 were defined as obese, and patients with a BMI (kg/m2) <30 were defined as non-obese. All 136 obese patients observed were divided retrospectively into 2 groups according to the devices used for dissection: 83 patients (Historical group: B) on whom dissection and coagulation were performed using other energy sources (monopolar electrocautery scissors, bipolar electrical energy, ultrasonic coagulating shears) and 53 patients who were treated with electrothermal bipolar vessel sealing (Caiman group: A). In group A, the Laparoscopic Caiman 5 (Aesculap AG, Tuttlingen, Germany) was the only instrument employed in the whole procedure. The study examined only three types of operation: right colectomy (RC), left colectomy (LC), and anterior resection (AR). Preoperative data were similar for RC, LC, and AR in both groups (A and B). The mean operative time was statistically shorter in the Caiman group than in the Historical group [104 vs 124 min (p 0.004), 116 vs 140 min (p 0.004), and 125 vs 151 min (p 0.003) for RC, LC, and AR between group A and B, respectively]. Also intraoperative blood loss results significantly lower in the Caiman group than in the historical one [52 ml vs 93 for RC (p 0.003); 65 vs 120 ml for LC (p 0.001); 93 vs 145 ml for AR (p 0.002) between group A and B, respectively]. No intraoperative complications were recorded in either group. The mean conversion rate was 4.4% (6 patients). There were no statistical differences in intensive care unit (ICU) stay, functional outcomes, mean hospital stay and overall morbidity rate between the two groups. There was no mortality in either group. The use of the Caiman EBVS instrument shows significant advantages with respect to a small number of intraoperative parameters. We can conclude that use of this radiofrequency device, in the laparoscopic approach, offers advantages in terms of lower intraoperative blood loss and shorter operative time in obese patients with colorectal cancer.

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Abstract Caiman 5 mm

Rationale, bench testing and in vivo evaluation of a novel 5 mm laparoscopic vessel sealing device with homogeneous pressure distribution in long instrument jaws

Stefan Eick, Brandon Loudermilk, Erik Walberg, Moritz N Wente


Background: In 1998, an electrothermal bipolar vessel sealing (EBVS) system was introduced and quickly became an integral component of the surgical armamentarium in various surgical specialties. Currently available EBVS instrumentsuse a scissor-like jaw configuration and closing mechanism, which causes decreasing compression pressure from the proximal to the distal end of the jaws. A new EBVS system is described here which utilizes a different instrument jaw configuration and closing mechanism to enable a more homogeneous pressure distribution despite longer instrument jaws.

Methods: Results of jaw pressure distribution measurements as well as sealing experiments with subsequent burst pressure measurements ex vivo on bovine uterine arteries are demonstrated. Furthermore, an in vivo evaluation of the new EBVS system in a canine and porcine model including histological examination is presented.

Results: The device revealed an even pressure distribution throughout the whole jaw length. The ex vivo burst pressure measurements revealed high average burst pressures, above 300 mmHg, independent of the outer diameter (1 to 7 mm) of the tested vessels. Histological evaluation of sealed vessels 21 days postoperatively demonstrated sealed and fused vessels without adjacent tissue damage.

Conclusions: The even pressure distribution leading to a sufficient tissue sealing in combination with the novel closing mechanism and extended jaw length differentiates the novel device from other available EBVS systems. This might offer a reduction of the overall procedure time, which should be further evaluated in a clinical study.

Keywords: Surgical instruments, Tissue sealing, Laparoscopic surgery, Hemostasis, Electrocoagulation, Electrosurgery, Thermal injury, Burst pressure, Equipment design. 

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