여성복 재킷 생산라인의 라인 밸런싱에 관한 연구 - 공정편성 효율을 중심으로 -

The cycle time on tram line T is theoretically defined as a sum of the total operating (travel) time on line To and the total time at terminals tt. In order to ensure the increasing of the operating and cycle speeds of trams in Zagreb, as well as increasing the gross transport work of a single line with the same number of trams and drivers in one shift, this paper has explored a scenario for simulating cycle time savings by reducing the total operating time, both achieved by the possible implementation of tram priority via traffic lights based on the local automation. Possible realistic saving of the total operating time ΔTo on line No. 17 in Zagreb is based on the assumption that all signals at the traffic lights for trams should be green due to tram priority via traffic lights. Real operating time savings ΔTo was measured by using the stopwatch - pencil - record list method. The measurements were conducted in the middle shift during the afternoon peak load, as well as in the early shift during the morning peak load, for all of the seven days in one week, and for the new tram NT 2200 which accounts for 51% of the ZET tram fleet, on line No. 17. This paper has explored the ideal and maximum positive cycle time scenario, based on the measurement of possible maximum operating time savings ΔTo as the sum of the duration of all red signals at traffic lights for trams in one cycle in real traffic situations in Zagreb.

Aim To evaluate the impact of COVID-19 on operative timing for hand trauma in a plastic surgery tertiary referral centre. Method Data was collected retrospectively on 80 patients who underwent surgical management for closed hand fractures, digital nerve injuries, and tendon injuries. Forty patients were in the pre-covid group (Jan-Mar 2019) and 40 in the post-covid group (Jan-Mar 2022). Outcome measures:Mean number of days between decision to operate and operation (operative delay time)Adherence to the operative timing requirements, as set by the British Society for Surgery of the Hand (BSSH) Results There was a statistically significant difference in operative delay time between the pre-covid group and the post-covid pre-vaccine group for hand fractures (2.5 vs 3.9, P = 0.0503), tendon injuries (1.4 vs 2.2, p = 0.016), and overall (1.9 vs 3.3, p = 0.0024). There was no significant difference between the 2 groups for nerve injuries (3.8 vs 1.8, p = 0.3062). In the post-covid group, BSSH operative timing requirements were met for a lower proportion of patients than the pre-covid group for hand fracture fixations (85% vs 100%), nerve repairs (87% vs 100%) tendon repairs (85% vs 100%). Overall, there was a statistically significant difference between the 2 groups (85% vs 100%, p = 0.0214). Operative delays were documented as being related to COVID-19 in 100% of patients who did not meet BSSH operative timing requirements. Conclusions COVID-19 has had a significant impact on operative timing for plastic surgery hand trauma. Further studies are needed to evaluate the usefulness of various interventions in the recovery of services following the COVID-19 global pandemic.

A hybrid algorithm based on MOSFLA and GA for multi-UAVs plant protection task assignment and sequencing optimization

To demonstrate the feasibility and potential of robotic single-site cholecystectomy, the study aimed to compare it with conventional laparoscopic cholecystectomy. In total, 791 consecutive patients underwent conventional laparoscopic cholecystectomy or robotic single-site cholecystectomy at our center between 2019 and 2022. After 1:1 propensity score matching, 117 patients for each group were selected. After propensity score matching, the only statistically significant difference between conventional laparoscopic cholecystectomy and robotic single-site cholecystectomy was operative time, which was 29.15 ±11.45 min in the conventional laparoscopic cholecystectomy group versus 38.57 ± 12.59 min in the robotic single-site cholecystectomy group (P < 0.001). Because the difference in surgical time between the two groups was minimal, it has little clinical relevance. Using cumulative sum analysis, the maturation phase of the total operation and docking times occurred after the 53rd case. To reduce bias, a comparison of results with conventional laparoscopic cholecystectomy and cases of robotic single-site cholecystectomy was performed in the maturation phase, which revealed only total operative time as statistically significant (P < 0.001). Robotic single-site cholecystectomy is a technically feasible and safe method for treating benign gallbladder diseases, with a relatively short learning curve and reasonable operative time.

Factors influencing cesarean delivery operative times: a prospective observational cohort study

BackgroundReconstruction of the maxillary defects following tumor ablation remains to be a challenge for surgeons. Virtual surgical planning (VSP), intraoperative cutting guides and stereolithographic models provides the head and neck reconstructive surgeon with powerful tools for complex reconstruction planning. Despite its use in fibular osteocutaneous reconstruction, application to the scapular free flap has not been as widely reported. The aim of this study was to compare aesthetic results and operation time of free scapular flap, with and without computer-aided design and computer-aided manufacturing (CAD/CAM) customized osteotomy guide, for reconstruction of maxillary defects.MethodsIn this prospective randomized controlled clinical trial study, we randomly assigned 22 patients with maxillary defects who were scheduled to undergo maxillary reconstruction with either free scapular flap with CAD/CAM customized osteotomy guide; study group (n = 11) or free scapular flap without CAD/CAM customized osteotomy guide; control group (n = 11). All patients were followed up for 3 months. The aesthetic outcome, operation and ischemic times were evaluated and compared.ResultsAesthetic outcomes were evaluated objectively by means of differential surface area (sagittal and axial) measurement, which showed improved aesthetic outcome (contour symmetry) in the study group with a mean of (241.39 ± 113.74 mm2), compared to patients in control group with a mean of (358.70 ± 143.99 mm2). There were significant differences between the two groups (P < 0.05). Aesthetic outcomes were also evaluated subjectively by means of visual analogue scale (VAS) and patient’s satisfaction score (PSS). The postoperative aesthetic appearance was better in the study group with more patients satisfied than that in control group and there were statistically significant differences (P = 0.039). The mean total operative time was 678.81 min and 777.18 min in the study group and control group respectively (P < 0.05) and the mean ischemia time was 133.18 min and 195.72 min for study group and control group respectively (P < 0.05). The ischemia time and total operative time were shorter in the study group compared to those in the control group and there were no flap losses in both groups.ConclusionThe use of CAD/CAM prefabricated cutting guides facilitates scapular flap molding and placement, minimizes ischemic time and operating time as well as improves aesthetic outcomes.Trialregistration This trial was registered at ClinicalTrials.gov. Registration number: NCT03757286. Registration date: 28/11/2018

Feasibility and Learning Curve of Robotic Laparoendoscopic Single-Site Surgery in Gynecology

BackgroundTo evaluate whether the interval from prostate biopsy to radical prostatectomy (interval), number of biopsy cores and biopsy approach affect the difficulty of robot-assisted laparoscopic radical prostatectomy (RALP).MethodsA total of 209 patients with localized and locally advanced prostate cancer who underwent RALP from January 2016 to September 2017 in Shanghai Changhai hospital were enrolled. All surgeries were performed by a single surgeon with experience of over 300 cases. The operative time was divided into seven periods based on eight relatively stable checkpoints based on prospectively recorded surgical videos. Total operative time and segmented operative time were recorded. Interval was categorized as <2, 2 to 4, 4 to 6, 6 to 8, and >8 weeks. Univariate analysis and multivariate linear regression analysis were applied.ResultsHigher body mass index (BMI), larger prostate volume and lymph node dissection (all P≤0.05) were independent predictors of longer total operative time. There was no clinically significant difference of operative time among Interval groups by multivariate linear regression analysis. But Interval was associated with operative time of step 5 in univariate analysis, in which operative time of the group with Interval less than 2 weeks was significantly longer than that of the other groups (P=0.010).ConclusionsFor an experienced surgeon, the interval from biopsy to RALP was not clinically associated with segmented operative time. Our results indicated that experienced surgeons may perform the operation before the traditionally recommend interval of 6 to 8 weeks.

To present the positive impact of technique standardization on successful outcome, fluoroscopy, and total operating time (TOT) shortening in a prospective study. Six experienced endourologists participated. To assess whether the adaptation of standardized surgical steps improved their methodology with time, 253 patients were prospectively divided in three consecutive 1-month groups. Patients underwent stent placement and exchange and total operating and fluoroscopy times (FTs) were recorded. All surgeons were unaware of their mean recorded results until the end of the study. At the end of the third month, we evaluated if the suggested technique standardization established a decrease for both FT and TOT. Statistical significance was set to p < 0.05. Total operating and FTs were significantly reduced with time between all groups of patients. For stent placement, TOT showed significant reduction between Groups A and C (p < 0.001), while between other group comparisons did not reach significance. FT showed a significant reduction (p < 0.001) in all group comparisons. For stent exchange, TOT reached significant improvement (p = 0.003) between Groups A and C, whereas between other groups was insignificant. FT improvement was significant between Groups A and C (p < 0.001) and Groups B and C (p < 0.001), but insignificant between Groups A and B. Even in experienced hands, the adaptation of technique standardization results in significant decrease of total operating and FTs and it is independent from feedback regarding their time performance.

Saturday, September 29, 2018 10:30 am–12:00 pm Applying Deformity Concepts in Your Practice

The aim of this study was to compare the effects of LigaSure™ versus conventional bipolar techniques on operating time and blood loss during laparoscopic salpingo-oophorectomy in a randomized controlled trial. In three teaching hospitals, 100 women undergoing a laparoscopic salpingo-oophorectomy were randomized for LigaSure or conventional bipolar instruments. Primary outcome was operating time (from initial skin incision to removal of the specimen). Secondary outcome measures were total operating time (from initial skin incision to skin closure), time to dissect the ovarian and infundibulopelvic ligaments, intraoperative blood loss, and subjective judgment of the instrument used. There were no differences in operating time and total operating time using LigaSure versus conventional bipolar instruments: 41.0 vs. 39.2 min (p = 0.78; 95 % CI = -10.9 to 14.5) and 54.6 vs. 58.6 min (p = 0.46; 95 % CI = -14.8 to 6.8), respectively. The mean blood loss using LigaSure versus conventional bipolar instruments was 38 vs. 33 mL (p = 0.73; 95 % CI = -22.7 to 32.2). Various subjective efficacy and instrument handling parameters of the two instruments varied among participating centers. There were no significant differences in operating time and blood loss with the use of LigaSure compared to conventional bipolar instruments during laparoscopic salpingo-oophorectomy, even after correction for potential confounders.

Radiation Exposure and Operation Time in Percutaneous Endoscopic Lumbar Discectomy Using Fluoroscopy-Based Navigation System

The purpose of this study was to compare manual traction and fracture-table traction for the reduction and nailing of femoral shaft fractures. We evaluated the quality of the reduction, operative time, complications, and functional status of the patient. Eighty-seven consecutive adult patients with a unilateral fracture of the femoral diaphysis that did not extend into the knee joint or proximal to the lesser trochanter were enrolled in the study. Patients who were transferred to our institution more than forty-eight hours after injury; those with multiple-system injuries, injury to the ipsilateral lower extremity, or pathological fracture; and those who were unable or unwilling to provide consent or to return for follow-up were excluded. Forty-five patients were randomized to manual traction and forty-two, to fracture-table traction; all were treated in the supine position. The number of surgical assistants, operative and fluoroscopy time, complications, functional scores, and other outcomes were recorded. There were no significant differences between the groups with respect to age, gender, Glasgow Coma Score, Injury Severity Score, side or mechanism of injury, fracture type, or time from injury to treatment. Internal malrotation was significantly more common when the fracture table had been used: twelve (29%) of the forty-two femora were internally rotated by >10 compared with three (7%) of the forty-five treated with manual traction (p = 0.007). Total operative time, from the beginning of the patient positioning to the completion of the skin closure, was decreased from a mean of 139 minutes (range, 100 to 212 minutes) when the fracture table was used to a mean of 119 minutes (range, sixty-five to 180 minutes) when manual traction was used (p = 0.033). There was no significant difference between the two treatment groups with regard to the number of assistants per case (mean two; range, zero to three), fluoroscopy time, other complications including femoral shortening or lengthening, or functional status of the patient at one year. Compared with fracture-table traction with the patient in a supine position, manual traction for intramedullary nailing of isolated fractures of the femoral shaft is an effective technique that decreases operative time and improves the quality of the reduction.

In 2003, the Accreditation Council for Graduate Medical Education limited resident duty hours to 80 hours per week. More than a decade later, the effect of the limits on resident clinical competence is not fully understood. We sought to assess the effect of duty hour restrictions on resident performance of an uncomplicated cesarean delivery. We reviewed unlabored primary cesarean deliveries at Duke University Hospital after 34 weeks gestation, between 2003 and 2011. Descriptive statistics and linear regression were used to compare total operative time with incision to delivery time as a function of years since institution of the 80-hour workweek. Resident training level, subject body mass index, estimated blood loss, and skin closure method were controlled for in the regression model. We identified 444 deliveries that met study criteria. The mean (SD) total operative time in 2003-2004 was 43.3 (14.3) minutes and 59.6 (10.7) minutes in 2010-2011 (P < .001). Multivariable regression demonstrated an increase in total operative time of 1.9 min/y (P < .001) but no change in incision to delivery time (P = .05). The magnitude of increased operative time was seen among junior residents (2.0 min/y, P < .001) compared to that of senior residents (1.2 min/y, P = .06). Since introduction of the 2003 duty hour limits, there has been an increase of nearly 20 minutes in the time required for a routine cesarean delivery. It is unclear if the findings are due to a change in residency duty hours or to another aspect of residency training.

Few studies have compared the surgical results of single-incision robotic cholecystectomy (SIRC) with those of conventional laparoscopic cholecystectomy (CLC). The purpose of this study was to evaluate the relative clinical efficacy of SIRC by comparing the number of postoperative days, pain level and complications between the 2 surgical methods. We retrospectively collected demographic, perioperative and postoperative data for all patients who underwent SIRC or CLC performed by a single surgeon from June 2016 to May 2017. Operative time was recorded, divided into anesthesia time, docking time, console time and total operation time. Postoperative pain was measured with the Numerical Pain Rating Scale. A total of 121 patients underwent cholecystectomy during the study period, of whom 61 had SIRC and 60 had CLC. The mean total operation time of SIRC and CLC was 93.52 (SD 20.27) minutes and 37.67 (SD 19.73) minutes, respectively (p < 0.001). The total operation time excluding console time of SIRC was significantly longer than that of CLC (82.77 [SD 18.27] min v. 37.67 [SD 19.73] min) (p < 0.001). The mean Numerical Pain Rating Scale score was 4.73 (SD 1.23) (SIRC: 4.75 [SD 1.24]; CLC: 4.70 [SD 1.22]) (p = 0.8) within 1 hour after the operation; scores after 6 hours and 1 day decreased in a similar manner in the 2 groups (p = 0.1). Postoperative pain, use of an additional port, complication rates, operation time and cost of SIRC were similar to or greater than those of CLC. Large randomized controlled trials are needed to examine the true benefits of SIRC.