Construction of a nomogram model to predict technical difficulty in performing laparoscopic sphincter-preserving radical resection for rectal cancer

BACKGROUND Colorectal surgeons are well aware that performing surgery for rectal cancer becomes more challenging in obese patients with narrow and deep pelvic cavities.Therefore,it is essential for colorectal surgeons to have a comprehensive understanding of pelvic structure prior to surgery and anticipate potential surgical difficulties.AIM To evaluate predictive parameters for technical challenges encountered during laparoscopic radical sphincter-preserving surgery for rectal cancer.METHODS We retrospectively gathered data from 162 consecutive patients who underwent laparoscopic radical sphincterpreserving surgery for rectal cancer.Three-dimensional reconstruction of pelvic bone and soft tissue parameters was conducted using computed tomography(CT)scans.Operative difficulty was categorized as either high or low,and multivariate logistic regression analysis was employed to identify predictors of operative difficulty,ultimately creating a nomogram.RESULTS Out of 162 patients,21(13.0%)were classified in the high surgical difficulty group,while 141(87.0%)were in the low surgical difficulty group.Multivariate logistic regression analysis showed that the surgical approach using laparoscopic intersphincteric dissection,intraoperative preventive ostomy,and the sacrococcygeal distance were independent risk factors for highly difficult laparoscopic radical sphincter-sparing surgery for rectal cancer(P<0.05).Conversely,the anterior-posterior diameter of pelvic inlet/sacrococcygeal distance was identified as a protective factor(P<0.05).A nomogram was subsequently constructed,demonstrating good predictive accuracy(C-index=0.834).CONCLUSION The surgical approach,intraoperative preventive ostomy,the sacrococcygeal distance,and the anterior-posterior diameter of pelvic inlet/sacrococcygeal distance could help to predict the difficulty of laparoscopic radical sphincter-preserving surgery.

Progress and development directions of stimulation techniques for ultra-deep oil and gas reservoirs

By reviewing the development history of stimulation techniques for deep/ultra-deep oil and gas reservoirs,the new progress in this field in China and abroad has been summed up,including deeper understanding on formation mechanisms of fracture network in deep/ultra-deep oil and gas reservoir,performance improvement of fracturing fluid materials,fine stratification of ultra-deep vertical wells,and mature staged multi-cluster fracturing technique for ultra-deep and highly deviated wells/horizontal wells.In light of the exploration and development trend of ultra-deep oil and gas reservoirs in China,the requirements and technical difficulties in ultra-deep oil and gas reservoir stimulation are discussed:(1)The research and application of integrated geological engineering technology is difficult.(2)The requirements on fracturing materials for stimulation are high.(3)It is difficult to further improve the production in vertical profile of the ultra-deep and hugely thick reservoirs.(4)The requirements on tools and supporting high-pressure equipment on the ground for stimulation are high.(5)It is difficult to achieve efficient stimulation of ultra-deep,high-temperature and high-pressure wells.(6)It is difficult to monitor directly the reservoir stimulation and evaluate the stimulation effect accurately after stimulation.In line with the complex geological characteristics of ultra-deep oil and gas reservoirs in China,seven technical development directions are proposed:(1)To establish systematic new techniques for basic research and evaluation experiments;(2)to strengthen geological research and improve the operational mechanism of integrating geological research and engineering operation;(3)to develop high-efficiency fracturing materials for ultra-deep reservoirs;(4)to research separated layer fracturing technology for ultra-deep and hugely thick reservoirs;(5)to explore fracture-control stimulation technology for ultra-deep horizontal well;(6)to develop direct monitoring technology for hydraulic fractures in ultra-deep oil and gas reservoirs;(7)to develop downhole fracturing tools with high temperature and high pressure tolerance and supporting wellhead equipment able to withstand high pressure.