Measuring surgical safety during minimally invasive surgical procedures: a validation study.

BACKGROUND: During the implementation of new interventions (i.e., surgical devices and technologies) in the operating room, surgical safety might be compromised. Current safety measures are insufficient in detecting safety hazards during this process. The aim of the study was to observe whether surgical teams are capable of measuring surgical safety, especially with regard to the introduction of new interventions. METHODS: A Surgical Safety Questionnaire was developed that had to be filled out directly postoperative by three surgical team members. A potential safety concern was defined as at least one answer between (strongly) disagree and indifferent. The validity of the questionnaire was assessed by comparison with the results from video analysis. Two different observers annotated the presence and effect of surgical flow disturbances during 40 laparoscopic hysterectomies performed between November 2010 and April 2012. RESULTS: The surgeon reported a potential safety concern in 16% (85/520 questions). With respect to the scrub nurse and anesthesiologist, this was both 9% (46/520). With respect to the preparation, functioning, and ease of use of the devices in 37.5-47.5% (15-19/40 procedures) a potential safety concern was reported by one or more team members. During procedures after which a potential safety concern was reported, surgical flow disturbances lasted a higher percentage of the procedure duration [9.3 ± 6.2 vs. 2.9 ± 3.7% (mean ± SD), p < .001]. After procedures during which a new instrument or device was used, more potential safety concerns were reported (51.2 vs. 23.1%, p < .001). CONCLUSIONS: Potential safety concerns were especially reported during procedures in which a relatively high percentage of the duration consisted of surgical flow disturbances and during procedures in which a new instrument or device was used. The Surgical Safety Questionnaire can act as a validated tool to evaluate and maintain surgical safety during minimally invasive procedures, especially during the introduction of a new intervention.

Identification of risk factors in minimally invasive surgery: a prospective multicenter study.

BACKGROUND: Since the introduction of minimally invasive surgery (MIS), concerns for patient safety are more often brought to the attention. Knowledge about and awareness of patient safety risk factors are crucial in order to improve and enhance the surgical team, the environment, and finally surgical performance. The aim of this study was to identify and quantify patient safety risk factors in laparoscopic hysterectomy and to determine their influence on surgical outcomes. METHODS: A prospective multicenter study was conducted from April 2014 to January 2016, participating gynecologists registered their performed laparoscopic hysterectomies (LHs). If deemed necessary, gynecologists could fill out a checklist with validated patient safety risk factors. Association between procedures with and without an occurred risk factor(s) and the surgical outcomes (blood loss, operative time, and complications) were assessed, using multivariate logistic regression and generalized estimation equations. RESULTS: Eighty-five gynecologists participated in the study, registering a total of 2237 LHs. For 627(28 %) procedures, the checklist was entered (in total 920 items). The most reported risk factors were related to the surgeon (19.6 %), the surgical team (14.4 %), technology (16.6 %), and the patient (26.8 %). The procedures where a risk factor was registered had significantly less favorable outcomes, higher complication rate (10.5 vs. 4.8 % (p = 0.002), longer operative time [114 vs. 95 min (p < 0.001)], and more blood loss [110 vs. 168 mL (p = 0.047)], which was mainly due to the technological and patient-related risk factors. CONCLUSION: Technological incidents are the most important and clinically relevant risk factors affecting surgical outcomes of LH. Future improvements of MIS need to focus on this. As awareness of safety risk factors in MIS is important, embedding of a safety risk factor checklist in registration systems will help surgeons to evaluate and improve their individual performance. This will inherently improve the surgical outcomes and thus patient safety.

Surgical flow disturbances in dedicated minimally invasive surgery suites: an observational study to assess its supposed superiority over conventional suites.

BACKGROUND: Minimally invasive surgery (MIS) is frequently compromised by surgical flow disturbances due to technology- and equipment-related failures. Compared with MIS in a conventional cart-based OR, performing MIS in a dedicated integrated operating room (OR) is supposed to be beneficial to patient safety. The aim of this study was to compare a conventional OR with an integrated OR with regard to the incidence and effect of equipment-related surgical flow disturbances during an advanced laparoscopic gynecological procedure [laparoscopic hysterectomy (LH)]. METHODS: Using video recording, 40 LHs performed between November 2010 and April 2012 (20 in a conventional cart-based OR and 20 in an integrated OR) were analyzed by two different observers. Outcome measures were the number, duration and effect (on a seven-point ordinal scale) of the surgical flow disturbances (e.g., malfunctioning, intraoperative repositioning, setup device). RESULTS: A total of 103 h and 45 min was observed. The interobserver agreement was high (kappa .85, p < .001). Procedure time was not significantly different (NS) [conventional OR vs. integrated OR, minutes ± standard deviation (SD), mean 161 ± 27 vs. 150 ± 34]. A total of 1651 surgical flow disturbances were observed (mean ± SD per procedure 40.8 ± 19.4 vs. 41.8 ± 15.9, NS). The mean number of surgical flow disturbances per procedure with regard to equipment was 6.3 ± 3.7 versus 8.5 ± 4.0, NS. No clinically relevant differences in the mean effect of these disturbances on the surgical flow between the two OR setups were observed. CONCLUSIONS: Performing LH in an integrated OR did not reduce the number of surgical flow disturbances nor the effect of these disturbances. Furthermore, in the integrated OR, repositioning of the monitors was a frequent and time-consuming source of disturbance. In order to maintain the high standard of surgical safety, the entire surgical team has to be aware that by performing surgery in an integrated OR different potential source for disruption arise.

Relevance of motion-related assessment metrics in laparoscopic surgery.

INTRODUCTION: Motion metrics have become an important source of information when addressing the assessment of surgical expertise. However, their direct relationship with the different surgical skills has not been fully explored. The purpose of this study is to investigate the relevance of motion-related metrics in the evaluation processes of basic psychomotor laparoscopic skills and their correlation with the different abilities sought to measure. METHODS: A framework for task definition and metric analysis is proposed. An explorative survey was first conducted with a board of experts to identify metrics to assess basic psychomotor skills. Based on the output of that survey, 3 novel tasks for surgical assessment were designed. Face and construct validation was performed, with focus on motion-related metrics. Tasks were performed by 42 participants (16 novices, 22 residents, and 4 experts). Movements of the laparoscopic instruments were registered with the TrEndo tracking system and analyzed. RESULTS: Time, path length, and depth showed construct validity for all 3 tasks. Motion smoothness and idle time also showed validity for tasks involving bimanual coordination and tasks requiring a more tactical approach, respectively. Additionally, motion smoothness and average speed showed a high internal consistency, proving them to be the most task-independent of all the metrics analyzed. CONCLUSION: Motion metrics are complementary and valid for assessing basic psychomotor skills, and their relevance depends on the skill being evaluated. A larger clinical implementation, combined with quality performance information, will give more insight on the relevance of the results shown in this study.

Risk factors in patient safety: minimally invasive surgery versus conventional surgery.

BACKGROUND: This study aimed to identify the frequency of events in the different patient safety risk domains during minimally invasive surgery (MIS) and conventional surgery (CS). METHODS: A convenience sample of gynecologic MIS and CS was observed. Events were observed and categorized into one of the predefined patient safety risk domains. RESULTS: A total of 53 procedures were observed: 26 CS and 27 MIS procedures. The general characteristics were comparable between the two groups. A large number of environmental events were observed, averaging one every 2.5 min. Technical events and events of an organizational nature occurred more often in MIS (P < 0.01) than in CS (P < 0.01). The relative risk for the occurrence of one or more technical events in MIS compared with CS was 1.7, and the risk for two or more technical events was 4.1. A time out according to protocol showed no relationship to the occurrence of the different types of patient safety-related events. CONCLUSION: The technological complexity inherent in MIS makes this type of surgery more prone to technology-related problems than CS, even in a specially designed minimally invasive surgical suite. A regular time-out procedure developed for CS lacks the attention necessary for the complex technology used in MIS and therefore is insufficient for MIS procedures briefing. Incorporating a specially designed technology checklist in a regular briefing protocol could be a solution to decrease the number of events in MIS.

Visual force feedback in laparoscopic training.

BACKGROUND: To improve endoscopic surgical skills, an increasing number of surgical residents practice on box or virtual reality (VR) trainers. Current training is focused mainly on hand-eye coordination. Training methods that focus on applying the right amount of force are not yet available. METHODS: The aim of this project is to develop a low-cost training system that measures the interaction force between tissue and instruments and displays a visual representation of the applied forces inside the camera image. This visual representation continuously informs the subject about the magnitude and the direction of applied forces. To show the potential of the developed training system, a pilot study was conducted in which six novices performed a needle-driving task in a box trainer with visual feedback of the force, and six novices performed the same task without visual feedback of the force. All subjects performed the training task five times and were subsequently tested in a post-test without visual feedback. RESULTS: The subjects who received visual feedback during training exerted on average 1.3 N (STD 0.6 N) to drive the needle through the tissue during the post-test. This value was considerably higher for the group that received no feedback (2.6 N, STD 0.9 N). The maximum interaction force during the post-test was noticeably lower for the feedback group (4.1 N, STD 1.1 N) compared with that of the control group (8.0 N, STD 3.3 N). CONCLUSIONS: The force-sensing training system provides us with the unique possibility to objectively assess tissue-handling skills in a laboratory setting. The real-time visualization of applied forces during training may facilitate acquisition of tissue-handling skills in complex laparoscopic tasks and could stimulate proficiency gain curves of trainees. However, larger randomized trials that also include other tasks are necessary to determine whether training with visual feedback about forces reduces the interaction force during laparoscopic surgery.

Suturing intraabdominal organs: when do we cause tissue damage?

BACKGROUND: It is generally assumed that safety of tissue manipulations during (laparoscopic) surgery is related to the magnitude of force that is exerted on the tissue. To provide trainees with performance feedback about tissue-handling skills, it is essential to define objective criteria for judging the safety of applied forces. To be of clinical relevance, these criteria should relate the applied forces to the risk of tissue damage. This experimental study was conducted to determine which tractive forces during suturing cause tissue damage in different types of porcine tissues. METHODS: Tractive forces were applied on eight different tissue types (fascia, aorta, vena cava, peritoneum, small and large bowel, uterus, and fallopian tube) of 10 different pigs by placing increasingly higher loads on sutures in the tissue. We determined the load at what tissue damage occurred through visual inspection of the tissue. For each tissue sample, three consecutive measurements were performed. RESULTS: The average maximum acceptable force varied between 11.43 N for fascia to 1.25 N for fallopian tube. The difference in allowable force between these two structures is almost tenfold. Small bowel can be handled with a tractive force almost 1.5-fold higher than large bowel. CONCLUSIONS: Each tissue type was found to have its own individual range of acceptable maximum forces before visual tissue damage occurs. With the results presented in this study, it is possible to provide clinically relevant and validated feedback to trainees about their tissue-handling skills.

Force measurement platform for training and assessment of laparoscopic skills.

BACKGROUND: To improve endoscopic surgical skills, an increasing number of surgical residents practice on box or virtual-reality (VR) trainers. Current training is mainly focused on hand-eye coordination. Training methods that focus on applying the right amount of force are not yet available. METHODS: The aim of this project is to develop a system to measure forces and torques during laparoscopic training tasks as well as the development of force parameters that assess tissue manipulation tasks. The force and torque measurement range of the developed force platform are 0-4 N and 1 Nm (torque), respectively. To show the potential of the developed force platform, a pilot study was conducted in which five surgeons experienced in intracorporeal suturing and five novices performed a suture task in a box trainer. RESULTS: During the pilot study, the maximum and mean absolute nonzero force that the novice used were 4.7 N (SD 1.3 N) and 2.1 N (SD 0.6 N), respectively. With a maximum force of 2.6 N (SD 0.4 N) and mean nonzero force of 0.9 N (SD 0.3 N), the force exerted by the experts was significantly lower. CONCLUSIONS: The designed platform is easy to build, affordable, and accurate and sensitive enough to reflect the most important differences in, e.g., maximal force, mean force, and standard deviation. Furthermore, the compact design makes it possible to use the force platform in most box trainers.

Sensitivity to activated protein C during the menstrual cycle in women with and without factor VLeiden.

INTRODUCTION: Activated protein C (APC) resistance is associated with an increased risk of venous thrombosis. High levels of estradiol and progesterone, e.g. during ovarian stimulation and pregnancy, as well as exogenously administered estrogens and progestagens during oral contraceptive use, induce an acquired form of APC resistance. Several coagulation factors display a cyclic pattern during the menstrual cycle due to the fluctuation of estradiol and progesterone. The aim of the study was to evaluate whether varying levels of estradiol and progesterone during the menstrual cycle are associated with differences in sensitivity to APC. MATERIALS AND METHODS: Normalized APC sensitivity ratios (nAPCsr) were determined with the thrombin generation-based APC-resistance test at six different time points during the menstrual cycle in thirteen wildtype women and six women with factor VLeiden. RESULTS: Mean nAPCsr varied slightly during the menstrual cycle. Women without factor VLeiden were more likely to have lower nAPCsr at the beginning of the cycle than later on in the cycle (1.34 versus 1.54 and 1.58, Friedman ranking test p=0.009). CONCLUSIONS: The sensitivity to APC differs between the different phases of the menstrual cycle. This cyclic variability could be useful in improving studies on APC resistance in women.

Patient safety risk factors in minimally invasive surgery: a validation study.

This study was conducted to adapt and validate a patient safety (PS) framework for minimally invasive surgery (MIS) as a first step in understanding the clinical relevance of various PS risk factors in MIS. Eight patient safety risk factor domains were identified using frameworks from a systems approach to patient safety. A questionnaire was drafted containing 34 questions. Three experts in the field of patient safety critically reviewed the questionnaire on clinical relevance and completeness. The questionnaire was distributed among known patient safety experts in person and also sent electronically. A total of 41 questionnaires were distributed and the response rate was 71%. The intraclass correlation coefficient was 0.42 representing moderate agreement. For seven of nine risk domains, Cronbach's alpha was sufficient (α > 0.7). Mean scores of the risk domains showed the following order of influence on patient safety from high to low: surgeon's experience [6.6, standard deviation (SD) 0.5], technical skills surgeon (6.6, SD 0.7), technology (5.9, SD 1.1), complications (5.9, SD 1.2), social interaction (5.0, SD 1.0), leadership surgeon (5.4, SD 1.2), blood loss (5.0, SD 1.2), length of surgery (5.0, SD 1.3), surgical team (4.9, SD 1.3), fallibility (4.9, SD 1.3), patient (4.5, SD 1.5), safety measures (4.4, SD 1.5), and finally environment(3.9, SD 1.5). This study is an initiative to give insight into clinical relevance of the maze of PS risk factors in MIS. All investigated risk domains were considered to be of noticeable influence on PS. Nevertheless, it is possible to prioritize various risk domains. In fact, experience and technical skills of the surgeon, technology, and complications are rated as the most important risk factors, closely followed by social interaction and leadership of the surgeon. Patient, safety measures, and environment are rated as the least important risk factors.

Ectopic pregnancy: when is expectant management safe?

This study was conducted to evaluate expectant management in asymptomatic patients with an initial serum beta-hCG titer of <2,500 IU/l and to determine the independent ability of initial serum beta-hCG titers and trend of serum beta-hCG to predict successful expectant management. A cohort of patients (N = 418) with suspected ectopic pregnancy (EP) between January 1991 and July 2008 is described. Three groups were defined: group I (n = 182), immediate surgical intervention (<24 h); group IIa (n = 130), unsuccessful expectant management (surgical intervention during follow-up), and group IIb (n = 99), successful expectant management (spontaneous regression of trophoblast). Hospital protocol was not complied in 35 cases (Table 1). Beta-hCG levels >3,000 IU/l occur in our expectant management group; however, none of these cases were successful. Unnecessary surgery was prevented in 14% (n = 7) of asymptomatic patients with initial beta-hCG of >2,000 IU/l. The success rate of expectant management was 49%, without a rise in complication rate or number of acute cases. In conclusion, the initial serum beta-hCG cutoff level of 2,000 IU/l is not a rigid upper limit for accepting expectant management in suspected EP and best practice is case specific. In asymptomatic patients, the serum beta-hCG cutoff level of at least 2,500 IU/l can be used for expectant management. This cutoff could be higher, but interpretation is limited due to censure in follow-up inherent to the predefined clinical protocol. There is no gain in including patients for expectant management with initial serum beta-hCG level >3,000 IU/l.