Systematic review of skills transfer after surgical simulation-based training

BACKGROUND

Simulation-based training assumes that skills are directly transferable to the patient-based setting, but few studies have correlated simulated performance with surgical performance.

METHODS

A systematic search strategy was undertaken to find studies published since the last systematic review, published in 2007. Inclusion of articles was determined using a predetermined protocol, independent assessment by two reviewers and a final consensus decision. Studies that reported on the use of surgical simulation-based training and assessed the transferability of the acquired skills to a patient-based setting were included.

RESULTS

Twenty-seven randomized clinical trials and seven non-randomized comparative studies were included. Fourteen studies investigated laparoscopic procedures, 13 endoscopic procedures and seven other procedures. These studies provided strong evidence that participants who reached proficiency in simulation-based training performed better in the patient-based setting than their counterparts who did not have simulation-based training. Simulation-based training was equally as effective as patient-based training for colonoscopy, laparoscopic camera navigation and endoscopic sinus surgery in the patient-based setting.

CONCLUSION

These studies strengthen the evidence that simulation-based training, as part of a structured programme and incorporating predetermined proficiency levels, results in skills transfer to the operative setting.

Rising incidence of early-onset colorectal cancer in Australia over two decades: report and review

The average age at diagnosis for colorectal cancer (CRC) in Australia is 69, and the age-specific incidence rises rapidly after age 50 years. The incidence has stabilized or is declining in older age groups in Australia during recent decades, possibly related to the increased uptake of screening and high-risk surveillance. In the same time frame, a rising incidence of CRC in younger adults has been well-documented in the United States. This rise in incidence in the young has not been reported from other countries that share long-term exposure to westernised urban lifestyles. Using data from the Australian Institute of Health and Welfare, we examined trends in national incidence rates for CRC under age 50 years and observed that rates in people under age 40 years have been rising for the last two decades. We further performed a review of the literature regarding CRC in young adults to outline the extent of current understanding, explore potential risk factors such as obesity, alcohol, and sedentary lifestyles, and to identify the questions remaining to be addressed. Although absolute numbers might not justify a population screening approach, the dispersal of young adults with CRC across the primary health-care system decreases probability of their recognition. Patient and physician awareness, aided by stool and emerging blood-screening tests and risk profiling tools, have the potential to aid in identification of those young adults who would most benefit from a colonoscopy through early detection of CRCs or by removal of advanced polyps.

Medium-throughput Drug Screening of Patient-derived Organoids from Colorectal Peritoneal Metastases to Direct Personalized Therapy

PURPOSE

Patients with colorectal cancer with peritoneal metastases (CRPMs) have limited treatment options and the lowest colorectal cancer survival rates. We aimed to determine whether organoid testing could help guide precision treatment for patients with CRPMs, as the clinical utility of prospective, functional drug screening including nonstandard agents is unknown.

EXPERIMENTAL DESIGN

CRPM organoids (peritonoids) isolated from patients underwent parallel next-generation sequencing and medium-throughput drug panel testing ex vivo to identify specific drug sensitivities for each patient. We measured the utility of such a service including: success of peritonoid generation, time to cultivate peritonoids, reproducibility of the medium-throughput drug testing, and documented changes to clinical therapy as a result of the testing.

RESULTS

Peritonoids were successfully generated and validated from 68% (19/28) of patients undergoing standard care. Genomic and drug profiling was completed within 8 weeks and a formal report ranking drug sensitivities was provided to the medical oncology team upon failure of standard care treatment. This resulted in a treatment change for two patients, one of whom had a partial response despite previously progressing on multiple rounds of standard care chemotherapy. The barrier to implementing this technology in Australia is the need for drug access and funding for off-label indications.

CONCLUSIONS

Our approach is feasible, reproducible, and can guide novel therapeutic choices in this poor prognosis cohort, where new treatment options are urgently needed. This platform is relevant to many solid organ malignancies.

Port-site metastases following laparoscopic surgery

BACKGROUND

Application of laparoscopy to the resection of malignancy has been followed by a literature describing cases of metastatic involvement at laparoscopic port sites. These include patients who underwent surgery for early stage carcinoma and instances following laparoscopic procedures during which tumours were not dissected.

METHODS

Recently published clinical and experimental studies, and case reports related to this problem are reviewed; their relevance is discussed.

RESULTS

Experimental studies incorporating bench top and large animal models have confirmed that tumour cells may be redistributed to port sites during laparoscopic surgery either directly from contaminated instruments or indirectly via the insufflation gas. Small animal models suggest that the incidence of wound metastasis is increased following conventional laparoscopic surgery, and that it may be decreased by gasless laparoscopy or helium insufflation. This evidence suggests that the development of port-site metastases depends not only on the physical redistribution of tumour cells but also on the specific insufflation gas used, possibly because of influences on local metabolic or immune factors acting at the wound site.

CONCLUSION

Further research in this area is urgent. Until the issue is better understood, patients undergoing laparoscopic surgery for malignancy should be entered into clinical trials.

Association of Surgical Skill Assessment With Clinical Outcomes in Cancer Surgery

Importance

Complex surgical interventions are inherently prone to variation yet they are not objectively measured. The reasons for outcome differences following cancer surgery are unclear.

Objective

To quantify surgical skill within advanced laparoscopic procedures and its association with histopathological and clinical outcomes.

Design, Setting, and Participants

This analysis of data and video from the Australasian Laparoscopic Cancer of Rectum (ALaCaRT) and 2-dimensional/3-dimensional (2D3D) multicenter randomized laparoscopic total mesorectal excision trials, which were conducted at 28 centers in Australia, the United Kingdom, and New Zealand, was performed from 2018 to 2019 and included 176 patients with clinical T1 to T3 rectal adenocarcinoma 15 cm or less from the anal verge. Case videos underwent blinded objective analysis using a bespoke performance assessment tool developed with a 62-international expert Delphi exercise and workshop, interview, and pilot phases.

Interventions

Laparoscopic total mesorectal excision undertaken with curative intent by 34 credentialed surgeons.

Main Outcomes and Measures

Histopathological (plane of mesorectal dissection, ALaCaRT composite end point success [mesorectal fascial plane, circumferential margin, ≥1 mm; distal margin, ≥1 mm]) and 30-day morbidity. End points were analyzed using surgeon quartiles defined by tool scores.

Results

The laparoscopic total mesorectal excision performance tool was produced and shown to be reliable and valid for the specialist level (intraclass correlation coefficient, 0.889; 95% CI, 0.832-0.926; P < .001). A substantial variation in tool scores was recorded (range, 25-48). Scores were associated with the number of intraoperative errors, plane of mesorectal dissection, and short-term patient morbidity, including the number and severity of complications. Upper quartile-scoring surgeons obtained excellent results compared with the lower quartile (mesorectal fascial plane: 93% vs 59%; number needed to treat [NNT], 2.9, P = .002; ALaCaRT end point success, 83% vs 58%; NNT, 4; P = .03; 30-day morbidity, 23% vs 50%; NNT, 3.7; P = .03).

Conclusions and Relevance

Intraoperative surgical skill can be objectively and reliably measured in complex cancer interventions. Substantial variation in technical performance among credentialed surgeons is seen and significantly associated with clinical and pathological outcomes.

Identification of early-stage colorectal cancer patients at risk of relapse post-resection by immunobead reverse transcription-PCR analysis of peritoneal lavage fluid for malignant cells

PURPOSE

Colorectal cancer patients diagnosed with stage I or II disease are not routinely offered adjuvant chemotherapy following resection of the primary tumor. However, up to 10% of stage I and 30% of stage II patients relapse within 5 years of surgery from recurrent or metastatic disease. The aim of this study was to determine if tumor-associated markers could detect disseminated malignant cells and so identify a subgroup of patients with early-stage colorectal cancer that were at risk of relapse.

EXPERIMENTAL DESIGN

We recruited consecutive patients undergoing curative resection for early-stage colorectal cancer. Immunobead reverse transcription-PCR of five tumor-associated markers (carcinoembryonic antigen, laminin gamma2, ephrin B4, matrilysin, and cytokeratin 20) was used to detect the presence of colon tumor cells in peripheral blood and within the peritoneal cavity of colon cancer patients perioperatively. Clinicopathologic variables were tested for their effect on survival outcomes in univariate analyses using the Kaplan-Meier method. A multivariate Cox proportional hazards regression analysis was done to determine whether detection of tumor cells was an independent prognostic marker for disease relapse.

RESULTS

Overall, 41 of 125 (32.8%) early-stage patients were positive for disseminated tumor cells. Patients who were marker positive for disseminated cells in post-resection lavage samples showed a significantly poorer prognosis (hazard ratio, 6.2; 95% confidence interval, 1.9-19.6; P = 0.002), and this was independent of other risk factors.

CONCLUSION

The markers used in this study identified a subgroup of early-stage patients at increased risk of relapse post-resection for primary colorectal cancer. This method may be considered as a new diagnostic tool to improve the staging and management of colorectal cancer.

Detection and Clinical Significance of Circulating Tumor Cells in Colorectal Cancer--20 Years of Progress

Circulating tumor cells (CTC) may be defined as tumor- or metastasis-derived cells that are present in the bloodstream. The CTC pool in colorectal cancer (CRC) patients may include not only epithelial tumor cells, but also tumor cells undergoing epithelial-mesenchymal transition (EMT) and tumor stem cells. A significant number of patients diagnosed with early stage CRC subsequently relapse with recurrent or metastatic disease despite undergoing "curative" resection of their primary tumor. This suggests that an occult metastatic disease process was already underway, with viable tumor cells being shed from the primary tumor site, at least some of which have proliferative and metastatic potential and the ability to survive in the bloodstream. Such tumor cells are considered to be responsible for disease relapse in these patients. Their detection in peripheral blood at the time of diagnosis or after resection of the primary tumor may identify those early-stage patients who are at risk of developing recurrent or metastatic disease and who would benefit from adjuvant therapy. CTC may also be a useful adjunct to radiological assessment of tumor response to therapy. Over the last 20 years many approaches have been developed for the isolation and characterization of CTC. However, none of these methods can be considered the gold standard for detection of the entire pool of CTC. Recently our group has developed novel unbiased inertial microfluidics to enrich for CTC, followed by identification of CTC by imaging flow cytometry. Here, we provide a review of progress on CTC detection and clinical significance over the last 20 years.

Intraperitoneal cell movement during abdominal carbon dioxide insufflation and laparoscopy. An in vivo model

PURPOSE

Possible mechanisms of movement of malignant cells within the peritoneal cavity during CO2 insufflation and laparoscopy involve direct transfer via laparoscopic instruments or dispersion of cells by CO2 or water vapor. An in vivo model has been developed to study these mechanisms.

METHODS

Laparoscopy was performed on an animal model (domestic white pig). Cells derived from colorectal cancer cell line Lim 1215 were injected to lie free within the peritoneal cavity. A polycarbonate filter system with a 5-micron pore diameter was used to examine CO2 expelled from the peritoneal cavity, during laparoscopy and manipulation of abdominal viscera, for malignant cells. Laparoscopic instruments and laparoscopic ports were washed independently, and fluid was centrifuged and examined for malignant cells.

RESULTS

Malignant cells were identified on 1 of 30 filters used to examine exhaust carbon dioxide. Malignant cells also were identified from 2 of 10 washings from laparoscopic ports and from 4 of 10 washings of laparoscopic instruments.

CONCLUSIONS

These results suggest that movement of cells throughout the peritoneal cavity during laparoscopy is via contaminated instruments, but local cell movement by dispersion possibly within water vapor from the port may also occur.

Receptor protein tyrosine kinase EphB4 is up-regulated in colon cancer

BACKGROUND

We have used commercially available cDNA arrays to identify EphB4 as a gene that is up-regulated in colon cancer tissue when compared with matched normal tissue from the same patient.

RESULTS

Quantitative RT-PCR analysis of the expression of the EphB4 gene has shown that its expression is increased in 82% of tumour samples when compared with the matched normal tissue from the same patient. Using immunohistochemistry and Western analysis techniques with an EphB4-specific antibody, we also show that this receptor is expressed in the epithelial cells of the tumour tissue and either not at all, or in only low levels, in the normal tissue.

CONCLUSION

The results presented here supports the emerging idea that Eph receptors play a role in tumour formation and suggests that further elucidation of this signalling pathway may identify useful targets for cancer treatment therapies.

Day-case haemorrhoidectomy

BACKGROUND

Ligation excision haemorrhoidectomy is usually performed on an inpatient basis. This study was designed to assess the feasibility of day-case haemorrhoidectomy.

METHODS

Patients fulfilling criteria for day surgery underwent ligation excision haemorrhoidectomy with the intention of a same-day discharge from hospital. A standardized protocol for anaesthesia, perioperative analgesia and antiemesis was followed. Patients received daily home nursing visits until they felt both comfortable and confident. Staff recorded pain and nausea scores on a visual analogue scale (range 1-10) until the first bowel action. Patient satisfaction was assessed independently after operation.

RESULTS

Fifty-one patients underwent planned day-case haemorrhoidectomy. Forty-two (82 per cent) were discharged on the day of surgery. All patients were discharged within 26 h of surgery. Four patients required readmission, two with reactive bleeding, one with urinary retention and one for pain control. Pain and nausea were well controlled. Forty-four patients (86 per cent) were totally or very satisfied with their overall care.

CONCLUSION

Ligation excision haemorrhoidectomy can be performed successfully as a day-case procedure.

Australasian Laparoscopic Colon Cancer Study shows that elderly patients may benefit from lower postoperative complication rates following laparoscopic versus open resection

BACKGROUND

A retrospective analysis of age-related postoperative morbidity in the Australia and New Zealand prospective randomized controlled trial comparing laparoscopic and open resection for right- and left-sided colonic cancer is presented.

METHODS

A total of 592 eligible patients were entered and studied from 1998 to 2005.

RESULTS

Data from 294 patients who underwent laparoscopic and 298 who had open colonic resection were analysed; 266 patients were aged less than 70 years and 326 were 70 years or older (mean(s.d.) 70.3(11.0) years). Forty-three laparoscopic operations (14.6 per cent) were converted to an open procedure. Fewer complications were reported for intention-to-treat laparoscopic resections compared with open procedures (P = 0.002), owing primarily to a lower rate in patients aged 70 years or more (P = 0.002). Fewer patients in the laparoscopic group experienced any complication (P = 0.035), especially patients aged 70 years or above (P = 0.019).

CONCLUSION

Treatment choices for colonic cancer depend principally upon disease-free survival; however, patients aged 70 years or over should have rigorous preoperative investigation to avoid conversion and should be considered for laparoscopic colonic resection.

REGISTRATION NUMBER

NCT00202111 (http://www.clinicaltrials.gov).

Transvaginal natural orifice translumenal endoscopic surgery (NOTES): a survey of women's views on a new technique

BACKGROUND

Laparoscopic and minimally invasive surgery has changed the surgical landscape irrevocably. Natural orifice translumenal endoscopic surgery (NOTES) offers the possibility of surgery without visible scars. Transvaginal entry offers potential benefits because it gains access to the peritoneal cavity without the need to open an abdominal viscus. Much of the discussion pertaining to NOTES focuses on technical and training issues, with little attention to date paid to the opinions of women. The perceptions of female health care workers and patients were sought in relation to their views on transvaginal NOTES.

METHODS

This study surveyed 300 women using a 12-point questionnaire devised by a multidisciplinary group of surgeons interested in minimally invasive surgery. The questionnaire was designed to establish the opinions of women with respect to NOTES surgery versus standard laparoscopic procedures. Responses were de-identified.

RESULTS

Three-fourths of the women surveyed were neutral or unhappy about the prospect of a NOTES procedure, and this remained constant even when it was stipulated that laparoscopic cholecystectomy and NOTES had equivalent safety and efficacy. Younger nulliparous women were most concerned about the potential negative effect of NOTES on sexual function. A minority were concerned about the cosmetic effect of surgery, although surgical scars were perceived as more important to younger respondents.

CONCLUSIONS

Potentially, NOTES surgery offers women a scarless operation with the possibility of less pain than experienced in standard laparoscopic surgery. Few women, however, were troubled about the cosmetic effect of surgery. The effect of NOTES on sexual function was expressed as a particular concern by younger women. In all groups and across all ages, peritoneal access using the transvaginal route was met by significant scepticism. In Australia, women remain to be convinced about the potential advantages of the emerging NOTES technology.

Core temperature changes during open and laparoscopic colorectal surgery

BACKGROUND

Perioperative hypothermia increases the morbidity of surgery. However, the true incidence of hypothermia during prolonged laparoscopic surgery is still unknown. To investigate this issue, we compared the temperature change between patients undergoing open and laparoscopic colorectal surgery.

METHODS

Sixty consecutive patients who were undergoing laparoscopic (33) or open (27) colorectal surgery had a transesophageal temperature probe placed after induction of anesthesia. Core temperature values were measured at 15-min intervals.

RESULTS

The groups were not statistically different with respect to age, sex, body surface area, or initial transesophageal temperature. The type of surgical access (open or laparoscopic) caused no difference in the incidence of hypothermia. The use of a forced-air warming device produced significantly less hypothermia during laparoscopic surgery. Men showed significantly less variability in temperature change than women.

CONCLUSIONS

The incidence of hypothermia in open and laparoscopic colorectal surgery is similar. Forced-air warming devices are of value in prolonged laparoscopic surgery. A gender difference in the response to a hypothermic situation has not been previously reported. This finding warrants further investigation.

Down-regulation of Fas gene expression in colon cancer is not a result of allelic loss or gene rearrangement

Expression of Fas, an apoptosis-inducing receptor, in colonic epithelium is progressively reduced during malignant transformation. We have examined the human Fas gene for loss of heterozygosity (LOH) and gross rearrangements in colon tumours and matched normal mucosa. Polymerase chain reaction (PCR) primers were designed to span a DraI restriction fragment length polymorphic site in the gene. Heterozygosity was detected in normal DNA samples by PCR amplification of the polymorphic site and restriction enzyme digestion. Thirty-eight of 88 patients (43%) with colon carcinomas were informative for the assay, and LOH was detected in 6 of the 38 (16%) corresponding tumours. Tumours from three patients with LOH did not express detectable Fas mRNA, and Fas expression was reduced or absent in 7 of 11 tumours from informative patients without LOH. Southern blotting of tumour DNA samples was used to detect rearrangement of the Fas gene, but no altered hybridization patterns were observed in 64 tumours analysed. These findings indicate that disruption of the Fas gene is not primarily responsible for the loss of Fas protein expression reported in colon cancer. We have also shown that loss of Fas gene transcription is common in these tumours, which may be due to epigenetic gene silencing.

Laparoscopic-assisted colonoscopic polypectomy: technique and preliminary experience

BACKGROUND

The majority of colonic polyps found at endoscopy are suitable for diathermy snare excision via colonoscope. Due to location or size, some are deemed unsafe to treat in this manner and therefore require colectomy. This study describes the technique and early results of a laparoscopic-assisted colonoscopic polypectomy technique that can be used to manage such polyps and thereby avoid laparotomy and colectomy.

METHODS

Colonoscopy with simultaneous laparoscopy was utilized to locate the site of the polyp. The colon was mobilized, if required, and the polyp resected by electrosurgical snare via the colonoscope while the serosal aspect of the colon was monitored laparoscopically.

RESULTS

The technique has been tried successfully in six patients. Three polyps were in the cecum and three were within the left colon. The size of the polyps ranged from 3 to 7 cm. All polyps were benign on histological examination. The patients were discharged on the day following the procedure. There were no complications.

CONCLUSIONS

The combination of laparoscopy with colonoscopic resection of a select group of large polyps represents a safe alternative to colonic resection.

Deregulation of apoptosis in colorectal carcinoma: theoretical and therapeutic implications

Apoptosis, or programmed cell death, maintains the structure of the colonic crypts by providing a balance to the rate of cell proliferation. Colorectal carcinoma arises partly from a disruption in this balance in the favour of uncontrolled growth. Until recently, most research into colon cancer has focused on the molecular regulators of cell-cycle progression and proliferation, but it is now evident that apoptosis is also defective. A failure of cells to die in response to premalignant damage may allow the progression of the disease and maintain the resistance of cancer cells to cytotoxic therapy. This review outlines the importance of apoptosis in the normal colon and presents recent studies that demonstrate that induction of apoptosis is defective in colonic tumours. When the molecular regulation of apoptosis is better understood, this knowledge may lead to the earlier detection of patients at greater risk of developing colorectal carcinoma, and also to the development of more effective therapies.

Screening and testing for COVID-19 before surgery

Background

Preoperative screening for coronavirus disease 2019 (COVID‐19) aims to preserve surgical safety for both patients and surgical teams. This rapid review provides an evaluation of current evidence with input from clinical experts to produce guidance for screening for active COVID‐19 in a low prevalence setting.

Methods

An initial search of PubMed (until 6 May 2020) was combined with targeted searches of both PubMed and Google Scholar until 1 July 2020. Findings were streamlined for clinical relevance through the advice of an expert working group that included seven senior surgeons and a senior medical virologist.

Results

Patient history should be examined for potential exposure to severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2). Hyposmia and hypogeusia may present as early symptoms of COVID‐19, and can potentially discriminate from other influenza‐like illnesses. Reverse transcription‐polymerase chain reaction is the gold standard diagnostic test to confirm SARS‐CoV‐2 infection, and although sensitivity can be improved with repeated testing, the decision to retest should incorporate clinical history and the local supply of diagnostic resources. At present, routine serological testing has little utility for diagnosing acute infection. To appropriately conduct preoperative testing, the temporal dynamics of SARS‐CoV‐2 must be considered. Relative to other thoracic imaging modalities, computed tomography has the greatest utility for characterizing pulmonary involvement in COVID‐19 patients who have been diagnosed by reverse transcription‐polymerase chain reaction.

Conclusion

Through a rapid review of the literature and advice from a clinical expert working group, evidence‐based recommendations have been produced for the preoperative screening of surgical patients with suspected COVID‐19.

Surgery triage during the COVID-19 pandemic

BACKGROUND

The novel coronavirus, SARS-CoV-2, caused the COVID-19 global pandemic. In response, the Australian and New Zealand governments activated their respective emergency plans and hospital frameworks to deal with the potential increased demand on scarce resources. Surgical triage formed an important part of this response to protect the healthcare system's capacity to respond to COVID-19.

METHOD

A rapid review methodology was adapted to search for all levels of evidence on triaging surgery during the current COVID-19 outbreak. Searches were limited to PubMed (inception to 10 April 2020) and supplemented with grey literature searches using the Google search engine. Further, relevant articles were also sourced through the Royal Australasian College of Surgeons COVID-19 Working Group. Recent government advice (May 2020) is also included.

RESULTS

This rapid review is a summary of advice from Australian, New Zealand and international speciality groups regarding triaging of surgical cases, as well as the peer-reviewed literature. The key theme across all jurisdictions was to not compromise clinical judgement and to enable individualized, ethical and patient-centred care. The topics reported on include implications of COVID-19 on surgical triage, competing demands on healthcare resources (surgery versus COVID-19 cases), and the low incidence of COVID-19 resulting in a possibility to increase surgical caseloads over time.

CONCLUSION

During the COVID-19 pandemic, urgent and emergency surgery must continue. A carefully staged return of elective surgery should align with a decrease in COVID-19 caseload. Combining evidence and expert opinion, schemas and recommendations have been proposed to guide this process in Australia and New Zealand.

Ischiorectal fossa block decreases posthemorrhoidectomy pain: randomized, prospective, double-blind clinical trial

PURPOSE

Hemorrhoidectomy can be associated with severe pain in the immediate postoperative period. The aim of this study was to assess the efficacy of a preemptive local anesthetic, ischiorectal fossa block, in the reduction of pain and analgesic requirements after hemorrhoidectomy.

METHODS

All patients were suitable for an established day surgery hemorrhoidectomy protocol. Immediately before surgery patients were randomly assigned either to receive (Group 1) or not receive (Group 2) the local anesthetic block. All other aspects of surgery and anesthesia were standardized. Nursing staff assessed pain at 30 minutes and 2, 4, and 24 hours postoperatively using a visual analog scale (1-10, where 1 represented no pain and 10 represented the worst pain imaginable). Analgesic requirements also were recorded at these times. Both the patients and the nursing staff were blinded to which local anesthetic protocol had been used.

RESULTS

Twenty patients were enrolled in the trial. Ten patients were randomly assigned to Group I and ten to Group 2. Mean pain scores for Group 1 (anal block) at 0.5, 2, 4, and 24 hours were 1.5, 1.8, 2.1, and 2.5, respectively, compared with Group 2, with mean pain scores of 3.4, 3.4, 3.9, and 5.1. These differences were statistically significant. Patients in Group 1 used less analgesia in the first 24 hours postoperatively than those in Group 2.

CONCLUSION

The use of a preemptive local anesthetic, ischiorectal fossa block, is associated with a significant decrease in pain and analgesia requirements after hemorrhoidectomy.

In vivo real-time analysis of intraperitoneal radiolabeled tumor cell movement during laparoscopy

PURPOSE

A porcine model has been developed to allow the real-time imaging of radiolabeled tumor cell movement throughout the peritoneal cavity, both at rest and during carbon dioxide insufflation.

METHODS

Fifteen 30-kg domestic white female pigs were used. Under anesthesia, 15 to 20 million radiolabeled human colorectal tumor cells (LIM1215) were introduced into the peritoneal cavity under laparoscopic vision into the pelvis. Radiolabeled tumor cell movement was examined by using a 25-cm-diameter, low-energy mobile gamma camera with high resolution collimator. Tumor cell movement and distribution during two hours without insufflation was examined in four pigs. Then tumor cell movement and distribution during two hours with CO2 insufflation was examined in four pigs. In a further four pigs, tumor cells were then mixed with blood and injected into the peritoneal cavity and the effect of no insufflation vs. insufflation was noted. A further three pigs were examined with manipulation of the intra-abdominal contents after injection of LIM1215 cells into the peritoneal cavity. Venting insufflating CO2 was filtered for tumor cells.

RESULTS

Widespread intraperitoneal distribution of tumor cells from the pelvis was identified both with CO2 insufflation of the peritoneal cavity and without insufflation. Tumor cells dispersed throughout the peritoneal cavity at a slower rate without carbon dioxide insufflation. There was a differential rate of tumor cell movement to the left upper quadrant and right upper quadrant with insufflation and without insufflation. Blood within the peritoneal cavity and an extended contact of the laparoscopic trocars with the peritoneal cavity in this setting increased contamination of the trocars and trocar sites with tumor cells. Tumor cells were identified on laparoscopic instruments in all experiments. No evidence of aerosolization of tumor cells was found.

CONCLUSION

Tumor cells move throughout the peritoneal cavity both at rest and during CO2 insufflation. The pattern of tumor cell dispersion differs with CO2 insufflation. The presence of blood and extended contact of trocars with peritoneal contents are a major factor in trocar and trocar site tumor cell contamination.

Non-technical skills of surgical trainees and experienced surgeons

Background

In addition to technical expertise, surgical competence requires effective non-technical skills to ensure patient safety and maintenance of standards. Recently the Royal Australasian College of Surgeons implemented a new Surgical Education and Training (SET) curriculum that incorporated non-technical skills considered essential for a competent surgeon. This study sought to compare the non-technical skills of experienced surgeons who completed their training before the introduction of SET with the non-technical skills of more recent trainees.

Methods

Surgical trainees and experienced surgeons undertook a simulated scenario designed to challenge their non-technical skills. Scenarios were video recorded and participants were assessed using the Non-Technical Skills for Surgeons (NOTSS) scoring system. Participants were divided into subgroups according to years of experience and their NOTSS scores were compared.

Results

For most NOTSS elements, mean scores increased initially, peaking around the time of Fellowship, before decreasing roughly linearly over time. There was a significant downward trend in score with increasing years since being awarded Fellowship for six of the 12 NOTSS elements: considering options (score −0·015 units per year), implementing and reviewing decisions (−0·020 per year), establishing a shared understanding (−0·014 per year), setting and maintaining standards (−0·024 per year), supporting others (−0·031 per year) and coping with pressure (−0·015 per year).

Conclusion

The drop in NOTSS score was unexpected and highlights that even experienced surgeons are not immune to deficiencies in non-technical skills. Consideration should be given to continuing professional development programmes focusing on non-technical skills, regardless of the level of professional experience.

Dipeptidase 1: a candidate tumor-specific molecular marker in colorectal carcinoma

The aim of this study was to identify tumor-specific markers for the detection of rare disseminated colorectal tumor cells in peripheral venous blood and in intra-peritoneal saline lavage samples collected before and after resection of colorectal tumors. Using cDNA micro-array screening, we found dipeptidase 1 (DPEP1) to be highly expressed in colon tumors compared to matched normal mucosa. Relative reverse transcriptase (RT)-PCR showed that DPEP1 was over-expressed by >/=2 fold in colon tumor compared to normal colonic mucosal tissue in 56/68 (82%) patients. Using immunobead RT-PCR, a technique that first enriches for epithelial cells, we found DPEP1 positive cells in intra-peritoneal lavage and venous blood samples from 15/38 (39%) colorectal cancer cases. This is the first report of DPEP1 as a marker for disseminated colon tumor cells.

Soluble HLA-G is a differential prognostic marker in sequential colorectal cancer disease stages

The expression of HLA-G by tumour cells is an established mechanism to escape recognition and immune mediated destruction, allowing tumour survival, growth and metastasis. However, the prognostic value of soluble HLA-G (sHLA-G) remains unknown. Mucinous carcinoma (MC) is a distinct form of colorectal cancer (CRC) found in 10 to 15% of patients, which has long been associated with poor response to treatment. To investigate the prognostic value of plasma sHLA-G levels in CRC patients, preoperative plasma sHLA-G levels were determined by ELISA in CRC patients (n = 133). In addition, the local expression of HLA-G in tumour biopsies was assessed using tissue microarray analysis (n = 255). Within the high 33rd percentile of sHLA-G levels (265-890 U/mL; n = 44) we observed higher frequency of MC patients (p = 0.012; Chi-square), and higher sHLA-G levels in patients with vascular invasion (p = 0.035; two-tailed t-test). Moreover, MC patients had significantly higher sHLA-G levels compared to those with adenocarcinoma not otherwise specified (p = 0.036; two-tailed t-test). Surprisingly, while stage II patients showed negative correlation between sHLA-G levels and liver metastasis free survival (LMFS) (p = 0.041; R = -0.321), in stage III patients high sHLA-G levels were associated with significantly longer LMFS (p = 0.002), and sHLA-G levels displayed positive correlation with LMFS (p = 0.006; R = 0.409). High HLA-G expression in tumours was associated with poor cancer specific overall survival in stage II to III (p = 0.01), and with shorter LMFS in stage II patients (p = 0.004). Our findings reveal that sHLA-G levels are associated with distinct progression patterns in consecutive disease stages, indicating a potential value as surrogate marker in the differential prognosis of CRC.

Variables in the spread of tumor cells to trocars and port sites during operative laparoscopy

BACKGROUND

Port-site recurrences have delayed the uptake of laparoscopic colectomy, but the etiology of these is incompletely understood. These studies were designed to investigate variables such as the size of the tumor inoculum and the volume and pressure of the insufflated gas during operative laparoscopy that might affect the deposition of these cells in relation to trocars and port sites.

METHODS

Radiolabeled human colon cancer cells were injected into the peritoneal cavity of pigs. Three trocars were inserted, and the abdomen was insufflated with carbon dioxide. The movement of cells within the abdomen was traced on a gamma camera. After 2 h, the trocars were removed and the port sites excised. Two studies were performed. In the first study, tumor inocula were varied from 1.5 x 10(5) to 120 x 10(5). In the second study, insufflation pressure was varied, with pressures 0, 4, 8 and 12 mmHg were studied.

RESULTS

When larger tumor inocula were injected, the contamination of both trocars (p = 0.005, Kendall's rank correlation) and trocar sites (p = 0.04, Kendall's rank correlation) increased. The deposition of cells on a trocar site was linked to contamination of its trocar (p = 0.03, chi-square), but the contamination of trocars did not always result in trocar-site contamination (p = 0.5, chi-square). Increased volumes of gas insufflation caused increased intraabdominal movement of tumour cells (p = 0.01, Kendall's rank correlation), although this did not lead to greater contamination of trocars or port sites (p = 0.82, Kendall's rank correlation). Decreased insufflation pressures resulted in increased contamination of trocars and port sites (p = 0.01, Kendall's rank correlation).

CONCLUSIONS

If clinical situations parallel this study, strategies such as increasing insufflation pressure, reducing episodes of desufflation and gas leaks, and using frequent intraabdominal lavage may help to reduce the numbers of viable tumor cells displaced to port sites during laparoscopic surgery for intraabdominal malignancy. This may reduce the rate of port-site metastases.