Impact of a surgical site infection reduction strategy after colorectal resection.

AIM: This study was performed to determine the impact of a surgical site infection (SSI) reduction strategy on SSI rates following colorectal resection. METHOD: American College of Surgeons National Surgical Quality Improvement Program (NSQIP) data from 2006-14 were utilized and supplemented by institutional review board-approved chart review. The primary end-point was superficial and deep incisional SSI. The inclusion criterion was colorectal resection. The SSI reduction strategy consisted of preoperative (blood glucose, bowel preparation, shower, hair removal), intra-operative (prophylactic antibiotics, antimicrobial incisional drape, wound protector, wound closure technique) and postoperative (wound dressing technique) components. The SSI reduction strategy was prospectively implemented and compared with historical controls (pre-SSI strategy arm). Statistical analysis included Pearson's chi-square test, and Student's t-test performed with spss software. RESULTS: Of 1018 patients, 379 were in the pre-SSI strategy arm, 311 in the SSI strategy arm and 328 were included to test durability. The study arms were comparable for all measured parameters. Preoperative wound class, operation time, resection type and stoma creation did not differ significantly. The SSI strategy arm demonstrated a significant decrease in overall SSI rates (32.19% vs 18.97%) and superficial SSI rates (23.48% vs 8.04%). Deep SSI and organ space rates did not differ. A review of patients testing durability demonstrated continued improvement in overall SSI rates (8.23%). CONCLUSION: The implementation of an SSI reduction strategy resulted in a 41% decrease in SSI rates following colorectal resection over its initial 3 years, and its durability as demonstrated by continuing improvement was seen over an additional 2 years.

Simulated colonoscopy training using a low-cost physical model improves responsiveness of surgery interns.

AIM: Surgery residents are required to become proficient in colonoscopy before completing training. The aim of this study was to evaluate the responsiveness of surgery interns to simulated colonoscopy training. METHOD: Interns, defined as postgraduate year 1 residents without exposure to endoscopy, underwent training in a physical model including colonoscopy, synthetic anatomy trays with luminal tattoos and a hybrid simulator. After baseline testing and mentored training, final testing was performed using five predetermined proficiency criteria. Content-valid metrics defined by the extent of departure from clinical reality were evaluated by two blinded assessors. Responsiveness was defined as change in performance over time and assessed comparing baseline testing with nonmentored final testing. RESULTS: Twelve interns (eight male, mean age 26, 80% right-handed) performed 48 colonoscopies each over 1 year. Improvement was seen in the overall procedure time (24 min 46 s vs 20 min 54 s; P = 0.03), passing the splenic flexure (20 min 33 s vs 10 min 45 s; P = 0.007), passing the hepatic flexure (23 min 31 s vs 12 min 45 s; P = 0.003), caecal intubation time (23 min 38 s vs 13 min 26 s; P = 0.008), the duration of loss of view of the lumen (75% vs 8.3%; P = 0.023), incomplete colonoscopy (100% vs 33.3%; P = 0.042), colonoscope withdrawal < 6 min (16.7% vs 8.3%; P = 0.052). Tattoo identification time (9 min 16 s vs 12 min 25 s; P = 0.50), colon looped time (2 min 12 s vs 1 min 45 s; P = 0.50) and rate of colon perforation (8.3% vs 8.3%; P = 1) remained unchanged. Interrater reliability was 1.0 for all measures. CONCLUSION: Simulated colonoscopy training in a low-cost physical model improved the performance of surgery interns with decreased procedure time, increased rates of complete colonoscopy and appropriate scope withdrawal.

Quality of total mesorectal excision and depth of circumferential resection margin in rectal cancer: a matched comparison of the first 20 robotic cases.

AIM: There are concerns about the impact of robotic proctectomy on the quality of total mesorectal excision (TME) and the impact of laparoscopic proctectomy on the depth of the circumferential resection margin (CRM). The aim of this study was to compare the first 20 consecutive robotic proctectomies performed in our unit with matched series of open and laparoscopic proctocolectomy performed by the same surgeon. METHOD: Data on the first 20 consecutive patients treated with robotic proctectomy for rectal cancer, <12 cm from the anal verge, by the senior author (RB) were extracted from a prospectively maintained database. Groups of patients treated with open and laparoscopic proctectomy, matched for age, gender and body mass index (BMI) with those undergoing robotic proctectomy, were selected. The quality of the TME was judged as complete, nearly complete or incomplete. CRM clearance was reported in millimetres. Physiological parameters and operative severity were assessed. RESULTS: Age (P = 0.619), Physiological and Operative Severity Score for the Enumeration of Morbidity and Mortality (POSSUM) score (P = 0.657), operative severity score (P = 0.977), predicted mortality (P = 0.758), comorbidities (P = 0.427), previous abdominal surgery (P = 0.941), tumour height (P = 0.912), location (P = 0.876), stage (P = 0.984), neoadjuvant chemoradiation (P = 0.625), operating time (P = 0.066), blood loss (P = 0.356), ileostomy (P = 0.934), conversion (P = 0.362), resection type (P = 1.000), flatus (P = 0.437), diet (P = 0.439), length of hospital stay (P = 0.978), complications (P = 0.671), reoperations (P = 0.804), reinterventions (P = 0.612), readmissions (P = 0.349), tumour size (P = 0.542; P = 0.532; P = 0.238), distal margin (P = 0.790), nodes harvested (P = 0.338) and pathology stage (P = 0.623) did not differ among the three groups. The quality of TME showed a trend to be lower following robotic surgery, although this was not statistically significant [open 95/5/15 (complete/nearly complete/incompete) vs laparoscopic 95/5/15 vs robotic 80/5/15; P = 0.235], but the degree of clearance at the CRM was significantly greater in robotic patients [open 8 (0-30) mm vs laparoscopic 4 (0-30) mm vs robotic 10.5 (1-30) mm; P = 0.02]. CONCLUSION: The study reports no statistically significant difference between open and laparoscopic techniques in the quality of TME during the learning curve of robotic proctectomy for rectal cancer and demonstrates an improved CRM.

Low-copy-number human transgene is recognized as an X inactivation center in mouse ES cells, but fails to induce cis-inactivation in chimeric mice.

X chromosome inactivation is initiated from a segment of the mammalian X chromosome called the X inactivation center. Transgenes from this region of the murine X chromosome are providing the means to identify the DNA needed for cis inactivation in mice. We recently showed that chimeric mice carrying transgenes from the human X inactivation center (XIC) region also provide a functional assay for human XIC activity; approximately 6 copies of a 480-kb human transgene (ES-10) were sufficient to initiate random X inactivation in cells of male chimeric mice (Migeon et al., 1999, Genomics, 59, 113-121). Now, we report studies of another human transgene (ES-5), which contains less than 300 kb of the human XIC region on Xq13.2 including an intact XIST locus and which has inserted in one or two copies into mouse chromosome 6. The ES-5 transgene is recognized as an X inactivation center in mouse embryonic stem cells, but is not sufficient to induce random X inactivation in somatic cells of highly chimeric mice. Human transgenes in chimeric mice provide a means to uncouple the key steps in this complex pathway and facilitate the search for essential components of the human XIC region.

Severe phenotypes associated with inactive ring X chromosomes.

Mental retardation and congenital malformations in individuals with small ring X chromosomes are often due to the functional disomy that results from failure of these chromosomes to undergo X inactivation. Such chromosomes either lack the XIST locus or do not express it. We have carried out genetic analysis of the ring X chromosomes from two girls with a 45,X/46,X,r(X) karyotype, mental retardation, and a constellation of abnormalities characteristic of the severe phenotype due to X disomy. In each case the ring X chromosome included an intact XIST locus which was expressed; the breakpoints were distal to DXS128, and therefore outside the XIC region; transcription analysis of alleles at the androgen receptor locus confirmed that these were inactive chromosomes. The characteristics of the XIST RNA were similar to the wild-type. Additional studies in cultured fibroblasts showed a second ring in a small percentage of the cells. The association of severe phenotype with an inactive X chromosome most likely reflects the presence of a second ring X chromosome which was active at least in some tissues during embryogenesis, but is no longer prominent in the tissues we analyzed.

Human X inactivation center induces random X chromosome inactivation in male transgenic mice.

X chromosome inactivation is the means to downregulate the transcriptional output of X chromosomes in female mammals. Essential DNA from the murine X inactivation center (Xic) has been identified by introducing it into male embryonic stem (ES) cells. To identify the essential sequences on human X chromosomes, we transfected male mouse ES cells with a YAC transgene containing 480 kb of the putative human X inactivation center (XIC). Despite little DNA sequence conservation, the human transgene is recognized as a second Xic in these XY mouse cells and induces random inactivation in chimeric mice derived from these cells. Inactivation is extensive on the X chromosome, but more localized on chromosome 11 carrying the transgene, demonstrating that initial inactivation and spreading of inactivation signals along the chromosome are independent events. Our results show for the first time that the DNA included in the human XIC transgene is sufficient to initiate random X inactivation, even in cells of another species. Interspecies XIC trangenes should facilitate further investigation of this process in humans and other mammals.