Cumulative Summation Test For Learning Curve Research Articles

Learning curve for biportal endoscopic posterior cervical foraminotomy determined using the cumulative summation test

BackgroundLearning curves describe the rate of performance improvements corresponding to the surgeon’s caseload, followed by a plateau where limited further improvements are observed. This study aimed to determine the learning curve for biportal full-endoscopic posterior cervical foraminotomy (BE-PCF) for the unilateral cervical foraminal disc.MethodsThe learning curve was evaluated using a learning curve cumulative summation test (LC-CUSUM). The goal for the operation time was set to 78 min, which is the mean operation time (mOT) of percutaneous full-endoscopic posterior cervical foraminotomy (PE-PCF) performed by a senior surgeon. Moreover, clinical outcomes and post-operative complications were compared between the early and late learning periods 1 year post-operatively.ResultsThis study enrolled the first 50 patients who underwent single-level BE-PCF, performed by a single surgeon. The LC-CUSUM signalled competency for surgery at the 20th operation, indicating that sufficient evidence was obtained to prove that the surgeon was competent. The mOT was 71.29 ± 11.69 min in BE-PCF, 71.84 ± 12.61 min in the early learning period, and 67.83 ± 10.31 min in the late learning period (p = 0.254). There was no statistical difference in clinical outcomes, visual analogue scale scores, and neck disability index between both periods (p > 0.05). Four complications were recorded throughout the whole period, with three in the early period and one in the late period (p = 0.285).ConclusionOur study shows that BE-PCF has a learning curve of 20 caseloads to achieve 90% proficiency, and it significantly reduces the operation time based on the performance of a senior surgeon proficient in PE-PCF.

Learning curve for microscopic unilateral laminectomy for bilateral decompression surgery using the cumulative summation test for learning curve.

A retrospective observational study The purpose of this study was to characterize the learning curve for a single level unilateral laminectomy and bilateral decompression in lumbar spinal stenosis using a learning curve cumulative summation test. Unilateral laminectomy and bilateral decompression for lumbar spinal stenosis proposes a potential benefit with minimizing surgery-related instability compared to traditional bilateral laminectomy, by preserving posterior stabilizing structures and contralateral facet joint and neural arch. Due to a narrow surgical corridor, it is considered to exhibit a steep learning curve as other types of minimally invasive procedures. However, there are few reports available regarding learning curve of unilateral laminectomy and bilateral decompression. The learning curve of a single surgeon performing single level unilateral laminectomy and bilateral decompression was assessed using learning curve cumulative summation test analysis. The surgeon had minimal experience in open decompressive laminectomy but no previous experience in unilateral laminectomy and bilateral decompression. Procedure success was defined as an operation time less than 75 minutes. Surgery related complications were recorded. Total 194 consecutive patients, who underwent primary single level unilateral laminectomy and bilateral decompression by a single spine surgeon, were included. The mean operative time for unilateral laminectomy and bilateral decompression was 64.6 ± 23.6 minutes. The mean operative time in the early learning period (≤29th case) was 80.6 ± 20.9 minutes, and that in the late learning period (after 29th case) was 61.8 ± 22.7 minutes, respectively. The overall complication rate was 13.9%. Majority of complications occurred in the early learning period. The learning curve cumulative summation test signaled competency for unilateral laminectomy and bilateral decompression at the 29th operation, indicating that the surgeon reached the competent level. In addition, based on the cumulative summation test, the surgeon seemed to maintain his competency for the procedure. This study showed that surgical experience reduced the operation time and surgery related complications. For inexperienced surgeon to achieve an acceptable outcome in unilateral laminectomy and bilateral decompression, minimum 30 cases of unilateral laminectomy and bilateral decompression are required to reach competent level of surgery.

An implementation of the learning curve cumulative summation test to evaluate a practicum for endometrial cancer ultrasound staging.

The learning curve cumulative summation (LC-CUSUM) test is commonly used as a quantitative assessment of the individual learning process. This study aimed to evaluate the skill acquisition process for performing ultrasound staging of endometrial cancer using the LC-CUSUM test. Sixty-seven ultrasound examinations performed by two operators were evaluated using the LC-CUSUM test according to their rate of success or failure to correctly stage myometrial invasion, serosa involvement, and pelvic and para-aortic lymph node involvement. The reference standard was the pathologic result. After the learning phase, the cumulative summation (CUSUM) test was applied to assess performance maintenance. The processes achieved satisfactory performance in the majority of the cases according to the established definitions. Operator 1 reached adequate performance within the 30th procedure for all the locations considered, while operator 2 performed fewer than 30 ultrasound examinations by the audit time. The CUSUM test confirmed that the target quality was preserved after the learning phase. Moreover, the ultrasound staging for endometrial cancer was highly accurate. Using the LC-CUSUM test made it possible to monitor the achievement and maintenance of a satisfactory performance quantitatively. The LC-CUSUM test could be a valuable instrument to survey diagnostic pathways in gynecological ultrasonography quantitatively.

Learning Curve for the Detection of Deep Infiltrating Endometriosis and Adenomyosis with 3-D Transvaginal Water Contrast Sonography.

Three-dimensional rectosonography (RSG) is a transvaginal sonography technique using rectal water contrast and 3-D acquisitions. The main points of interest of 3-D RSG could be its easy accessibility and its quick learning curve, especially with respect to rectosigmoid lesions. The objective of this prospective observational study was to assess the learning curve of 3-D RSG for the diagnosis of rectosigmoid lesions and for various other locations of deep endometriosis (DE), endometriomas and adenomyosis. From April 2017 to November 2017, 116 patients with suspected pelvic endometriosis were referred to the Croix-Rousse University Hospital, and those who underwent 3-D RSG were included in our study. After a short training period, four residents were asked to perform 3-D RSG by themselves. Each procedure was systematically controlled immediately afterward by a single expert sonographer. The success of the procedure involved the correct identification of various locations of endometriosis (rectosigmoid, uterosacral ligament, retrocervical space, vagina, bladder and ovaries) and adenomyosis, using the expert sonographer's examination as the reference technique. The learning curve was generated using these data and assessed using the Learning Curve Cumulative Summation Test (LC-CUSUM) method. The pooled LC-CUSUM revealed that the required level of achievement was reached after 24 3-D RSGs were performed for the diagnosis of rectosigmoid lesions. All four residents were significantly competent in diagnosing rectosigmoid lesions at the end of their training period, with an α risk <0.05 (T1, p=0.03; T2, p=0.0002; T3, p=0.05; T4, p=0.02). The LC-CUSUM analysis confirmed that competency was achieved for vaginal DE, torus uterinum DE, US DE, bladder DE, endometriomas and adenomyosis within 17, 27, 38, 19, 17 and 33 scans, respectively. This study provides evidence that the skills required to diagnose endometriosis lesions and adenomyosis with 3-D RSG can be acquired after a brief learning period in an expert center.

Ultrasound Block of the Medial Branch: Learning the Technique Using CUSUM Curves.

Background:Blocking the medial branch of the lumbar facet joints plays a fundamental diagnostic and therapeutic role in the treatment of lumbar pain. Attempts to replace the typical guided X-ray techniques with ultrasound-guided techniques have also involved treating the lumbar medial branches. By applying the cumulative sum control chart (CUSUM method), we sought to evaluate the learning curve associated with ultrasound-guided block of the lumbar medial branches in operators experienced in locoregional anesthesia but without expertise in pain therapy.Aim:This study aimed to use a repeatable method to identify the learning curve of the ultrasound-guided medial branch block.Settings and Design:This study was a prospective application of over forty consecutive procedures of ultrasound lumbar medial branch block.Materials and Methods:The ultrasound medial branch blocks were performed under ultrasound guidance with confirmation of correct positioning using fluoroscopy on a population of patients with low back pain with any body mass index (BMI).Statistical Analysis:The operator's performance was assessed using the learning curve cumulative summation test (LS-CUSUM).Results and Conclusions:The correct target was reached in 29 procedures out of a total of 40 (72.5%) and in 29 out of 36 procedures performed on patients with BMI <30 (80.5%). According to the CUSUM algorithm, 11 further consecutive successes would have been necessary (47 procedures in total) to achieve a proven learning of the technique in the group with only patients with a BMI <30, with a further 22 consecutive successes (62 procedures in total) in the general group. Ultrasound-guided block of the lumbar medial branch appears not to be optimal for training beginner/intermediate operators seeking to replace guided X-ray procedures with guided ultrasound.

Learning Curve For Lateral Meniscal Allograft Transplantation: Preventing Meniscal Extrusion

This study analyzes the large number of lateral meniscal allograft transplantation (LMAT) procedures conducted by a single surgeon over 23 years to determine whether the absolute amount of graft subluxation and the incidence of extrusion are different at the present time compared to the early MAT era. We reviewed 320 cases of LMAT performed by a single surgeon between 1996 and 2019. This cohort was chronologically divided into 8 groups (of 40 subjects). The absolute amount of subluxation was measured by the coronal sections of magnetic resonance images taken 1 year after operation. Subluxation by more than 3 mm was considered as extrusion. The graft extrusion learning curve was plotted in each series using the learning curve cumulative summation test (LC-CUSUM). Extrusion incidence was 41.6%, and the mean absolute amount of graft subluxation was 3.4 ± 2.2 mm for all subjects. There were significant between-group differences in extrusion incidence and absolute amount of graft subluxation (extrusion incidence, P < .001; absolute amount of graft subluxation, P < .001), and the extension incidence and graft subluxation decreased from Group I (72.5%, 4.6 ± 1.7) to Group VIII (27.5%, 2.5 ± 2.1). LC-CUSUM analysis signaled that the surgeon had achieved predefined acceptable outcomes in avoiding extrusion after 128 cases. The incidence of extrusion and absolute amount of graft subluxation decreased significantly over a period of 23 years, and the surgeon achieved a certain level of proficiency after 128 cases. Level IV, Case series.

Assessment of operator performance during oocyte retrievals: residents\u2019 learning curve and continuous monitoring of senior physicians

BackgroundThe learning curve cumulative summation test (LC CUSUM test) allows to define an individualized learning curve and determine the moment when clinical proficiency is attained. After acquisition of the skills, the cumulative summation test (CUSUM test) allows to monitor the maintenance of the required level over time. The LC CUSUM test has been frequently used in the field of Obstetrics and Gynecology (Ob/Gyn) for several procedures, but only once for OR.MethodsWe performed a retrospective study at Angers university hospital between May 2017 and September 2018. Seven Ob/Gyn residents and 5 senior physicians were included, and all OR performed during that time (n = 690) were analyzed. The performance index assessed was the oocyte retrieval rate (ORR), defined as the ratio of oocytes retrieved to follicles aspirated. We used the LC CUSUM test to analyze the learning curves of residents, and the CUSUM test to monitor the performance of senior physicians. An ORR ≥50% in 60% of retrievals was defined as the threshold for clinical proficiency.ResultsSix hundred seventy-four oocyte retrieval (OR) were included: 315 were performed by residents, 220 by senior physicians, and 139 by both residents and physicians (mixed retrievals). Four residents (57%) reached the threshold after aspirating 82, 67, 53 and 46 ovaries, respectively. The mean number of ovaries aspirated in order to reach clinical proficiency was 62, and the mean number of weeks needed was 21. The duration of the learning period varied between 26 and 80 days. Two senior physicians (40%) remained proficient across the duration of the study, while two physicians (40%) had one statistically “suboptimal” OR, and one physician (20%) had two suboptimal retrievals.ConclusionThere is a large variability in the duration of the learning period and the number of procedures needed for a resident to master OR. Senior physicians maintain an adequate performance.

HipSim — hip fracture surgery simulation utilizing the Learning Curve–Cumulative Summation test (LC-CUSUM)

Background and purpose — Virtual reality simulation of hip fracture surgery is available for orthopedic residents nationwide in Denmark. Summative assessment of learning applying the learning curve cumulative summation test (LC-CUSUM) has not been utilized in orthopedic simulation training. The strength of the LC-CUSUM is that it assumes incompetency and signals competency based on solid statistics. We investigated the LC-CUSUM characteristics of novices stepwise mastering the simulated dynamic hip screw (DHS) procedure. Material and methods — 32 1st-year orthopedic residents participated in HipSim and its 3 subsequent LC-CUSUM evaluations: placing a Kirschner wire, placing a Kirschner wire in different patients, and performing the entire DHS procedure in different patients. The career status of the participants, i.e., still working in orthopedics or in another specialty was recorded ≥ 2 years after participation and associated with the simulation performance (passed/failed). Results — 13/14 participants passing HipSim according to LC-CUSUM were still working in orthopedics, while 9/18 participants failing HipSim had quit orthopedics at ≥ 2 years follow-up. The simulator-generated feedback did not statistically significantly differ between the groups. Interpretation — LC-CUSUM and its summative pass/fail assessment of each simulation was feasible in this formative simulation program. Clinical educators can be reassured that participants passing HipSim are likely to continue to 2nd–5th year of residency, while failing HipSim should raise concerns and trigger career counselling and clinical supervision. The motivational aspect of LC-CUSUM pass/fail assessment when designing formative simulation training warrants further research.

Learning Curve for Lumbar Decompressive Laminectomy in Biportal Endoscopic Spinal Surgery Using the Cumulative Summation Test for Learning Curve

The purpose of the present study was to determine the learning curve for biportal endoscopic spinal surgery (BESS) for decompressive laminectomy in lumbar spinal stenosis using a learning curve cumulative summation test (LC-CUSUM). The surgeon was proficient in open and microscopic decompressive laminectomy in lumbar spinal stenosis but did not have any experience with BESS or other endoscopic surgery techniques. The learning curve of BESS was investigated using LC-CUSUM analysis. Procedure success was defined as an operative time <75 minutes, the mean operative time with microscopic decompression laminectomy. The present study included the first 60 patients who had undergone single-level decompressive laminectomy using BESS by a single orthopedic surgeon. The mean operative time for decompressive laminectomy by BESS was 83.8 ± 37.9 minutes. The mean operative time in the early learning period (≤30 cases) and late learning period (second 30 cases) was 105.3 ± 39.7 minutes and 62.4 ± 19.9 minutes, respectively. The overall complication rate was ∼10%. The LC-CUSUM signaled competency for surgery at the 58th operation, indicating that sufficient evidence had accumulated to prove that the surgeon was competent. Thus, a trainee with no experience with BESS had reached adequate performance at 58 cases. The results of the present study have demonstrated that a substantial learning period could be needed before adequate performance can be achieved with lumbar decompressive laminectomy using BESS.

Applying a statistical method in transvaginal ultrasound training: lessons from the learning curve cumulative summation test (LC-CUSUM) for endometriosis mapping

BackgroundMethods available for assessing the learning curve, such as a predefined number of procedures or direct mentoring are lacking. Our aim was to describe the use of a statistical method to identify the minimal training length of an experienced sonographer, newly trained in deep infiltrating endometriosis (DIE) mapping by evaluating the learning curve of transvaginal ultrasound (TVUS) in the preoperative assessment of endometriosis.MethodsA retrospective study in a tertiary referral center for endometriosis. Reports and stored data from TVUS scans performed by one operator with training in general gynecological ultrasound, but not in endometriosis mapping, were analyzed retrospectively for patients who subsequently underwent laparoscopy, which served as a reference standard. The performance of TVUS was assessed for the following sites: endometriomas, bladder, vagina, pouch of Douglas, bowel and uterosacral ligaments, and correlated with laparoscopic findings. Sensitivity, specificity, PPV, NPV, and accuracy were calculated, and the operator’s diagnostic performance was assessed using the learning curve cumulative summation test (LC-CUSUM).ResultsData from 94 women were available for analysis. The learning curve using the LC-CUSUM graph showed that the sonographer reached the predefined level of proficiency in detecting endometriosis lesions after 20, 26, 32, 31, 38, and 44 examinations for endometriomas, bladder nodules, vaginal nodules, pouch of Douglas obliteration, bowel nodules, and uterosacral ligament nodules, respectively.ConclusionsLC-CUSUM allows monitoring of individual performance during the learning process of new methodologies. This study shows that a sonographer trained in general gynecologic ultrasonography, who devotes time to learn TVUS for DIE mapping, can achieve proficiency for diagnosing the major types of endometriotic lesions after examining less than 50 patients who subsequently undergo surgery in a training setting.

Use of the Learning Curve-Cumulative Summation Test for Leopold Maneuvers Assessment in a Simulator: A Pilot Study.

Simulation enables medical students to practice clinical skills in a safe environment. Graduates in medicine must be able to correctly perform an examination on a pregnant woman using Leopold maneuvers. Learning curves-cumulative summation (LC-CUSUM) may help determine when the student has achieved a specific skill. Our objective was to perform the LC-CUSUM test regarding the ability of students to correctly carry out Leopold maneuvers; a pregnancy simulator was used, transferring the results to a clinical setting. Five medical students were trained to carry out Leopold maneuvers using the simulator. Each student performed maneuvers for 50 cases of different fetus positions; a LC-CUSUM was plotted for each student. Afterward, the students performed the Leopold maneuvers on 5 pregnant women. Of the 5 students, 3 achieved a level of proficiency; the attempts needed for reaching this level were 13, 13, and 37, respectively. The other 2 students did not reach proficiency level. Of the students who became successfully proficient with the simulator, one of them attained a 100% success rate in pregnant patients, whereas the other two had success rates of 80%. The students who did not achieve a level of competency with the simulator had only a 60% success rate with patients. Because of the differences observed between students in the number of attempts needed for achieving proficiency in Leopold maneuvers, we believe that each student should build his/her own learning curve. Achieving competency in carrying out Leopold maneuvers using the simulator could be transferable to patients.

Proficiency in oocyte retrieval assessed by the learning curve cumulative summation test

The number of procedures required for a trainee to reach proficiency in oocyte retrieval and the criteria applied to define performance are not well defined. To evaluate the learning curve of oocyte retrieval, this study prospectively evaluated three trainees over 6months. Oocyte retrieval was monitored by the learning curve–cumulative summation test (LC-CUSUM), a specific statistical tool designed to indicate when a predefined level of performance is reached. Oocytes were retrieved from one ovary by the trainee and from the second ovary by a senior operator in a randomized manner. The main outcome measure was the ratio of oocytes collected and follicles aspirated. A trainee’s ratio of ⩾80% of the senior operator’s defined success. From 17 to >50 procedures were necessary for the trainees to reach the predefined level of performance. Cumulative summation tests implemented after the learning phase confirmed that performance was maintained. The present study confirms the large variability in acquiring proficiency for surgical procedures. It provides an exportable model for a quantitative tailored monitoring of the learning curve and for continuous monitoring of performance in oocyte retrieval.

Student Attainment of Proficiency in a Clinical Skill: The Assessment of Individual Learning Curves

The aims of this study were to determine if the learning curve cumulative summation test (LC-CUSUM) can differentiate proficiency in placing intravenous catheters by novice learners, and identify the cause of failure when it occurred. In a prospective, observational study design 6 undergraduate students with no previous experience of placing intravenous catheters received standardized training by a board certified veterinary anesthesiologist in intravenous catheter placement technique. Immediately following training, each student attempted 60 intravenous catheterizations in a dog mannequin thoracic limb model. Results were scored as a success or failure based upon completion of four specific criteria, and where catheter placement failure occurred, the cause was recorded according to pre-defined criteria. Initial acceptable and unacceptable failure rates were set by the study team and the LC-CUSUM was used to generate a learning curve for each student. Using 10% and 25% acceptable and unacceptable failure rates, 3 out of 6 students attained proficiency, requiring between 26 to 48 attempts. Applying 25% and 50% acceptable and unacceptable failure rates, 5 of 6 students obtained proficiency, requiring between 18 and 55 attempts. Wide inter-individual variability was observed and the majority of failed catheterisation attempts were limited to two of the four pre-defined criteria. These data indicate that the LC-CUSUM can be used to generate individual learning curves, inter-individual variability in catheter placement ability is wide, and that specific steps in catheter placement are responsible for the majority of failures. These findings may have profound implications for how we teach and assess technical skills.

An application of the learning curve–cumulative summation test to evaluate training for endotracheal intubation in emergency medicine

ObjectiveThe learning curve–cumulative summation (LC-CUSUM) test allows for quantitative and individual assessments of the learning process. In this study, we evaluated the process of skill acquisition for performing endotracheal intubation...

Learning Curve of Acetabular Cup Positioning in Total Hip Arthroplasty Using a Cumulative Summation Test for Learning Curve (LC-CUSUM)

Despite advances in surgical techniques and instrumentation, optimal cup positioning in total hip arthroplasty (THA) is challenging with a limited accuracy. We evaluated whether a learning curve exists for the optimal cup positioning, using the LC-CUSUM test (Learning curve cumulative summation test). We evaluated the first 100 consecutive THA performed by two surgeons, who had a year of fellowship training in the same teaching hospital. A learning curve of cup positioning was plotted in each series using the LC-CUSUM score. There was no significant difference of numbers of outlier between two surgeons (P = 0.079). Both surgeons completed the learning curve of optimal cup positioning before 50 procedures, and maintained competence. A substantial learning period is necessary in the optimal positioning of an acetabular cup.

Use of the Learning Curve–Cumulative Summation test for quantitative and individualized assessment of competency of a surgical procedure in obstetrics and gynecology: fetoscopic laser ablation as a model

We sought to determine the learning curve (LC) for fetoscopic laser photocoagulation (FLP) as a model for the evaluation of training in surgical procedures. A retrospective review of consecutive case series of FLP from 2 centers with 3 operators (operator I [O-I], observer trained; operator II [O-II], hands-on trained; and operator III [O-III], clinical fellow) was performed and the LC-cumulative summation (CUSUM) test was plotted. The acceptable and unacceptable success rates for at least 1 fetus survival after FLP were set at 82% and 70%, respectively, from a systematic review. A total of 171 consecutive cases were performed by the 3 operators (O-I, 91; O-II, 49; and O-III, 31). From LC-CUSUM test O-I needed 60 procedures, O-II needed 20 procedures, and O-III needed 20 procedures to reach an acceptable performance rate for at least 1 survivor. The LC-CUSUM test can be used to accurately assess the LC in a surgical procedure in obstetrics and gynecology. Hands-on trained operators exhibit a shorter LC.