SEARCH · PubMed Health

Results for “Learning Curve”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources

PubMed2006

Learning curve for total gastrectomy with D2 lymph node dissection: cumulative sum analysis for qualified surgery.

BACKGROUND: This study was conducted to evaluate the leaning curve of D2 lymph node dissection for patients with gastric cancer in a high-volume center. METHODS: The authors prospectively reviewed the data of all patients who underwent total gastrectomy with D2 lymph node dissection during a 4-year period. Retrieved lymph node number was used as a surrogate marker of oncological outcome. The retrieved lymph node number cut-off value required for satisfactory D2 lymph node dissection was defined as >25. Cumulative sum analysis was used to examine the learning curves of individual surgeons at target accuracy rates of 85%, 90%, 92.5%, 95%, and 98%. RESULTS: Two junior staff surgeons performed 198 curative-intent total gastrectomies with D2 lymph node dissections during the study period; their success rates exceeded 90%. Operating time decreased with operative experience (Pearson correlation coefficient = -0.515, P < 0.001). The learning period for total gastrectomy with D2 lymph node dissection for these two junior members of staff was calculated as 23-35 cases, presuming a 92.5% success rate. CONCLUSIONS: The current study suggests that the surgical learning period for D2 lymph node dissection extends to at least 23 cases or 8 months. In clinical trials containing gastric cancer surgery, the learning curve for qualified surgery from the standpoint of oncological outcome should be considered to minimize bias due to surgeon-associated factors.

Adenocarcinoma↗

PubMed2001

Learning curves for breast cancer sentinel lymph node mapping based on surgical volume analysis.

BACKGROUND: Implementation of new procedures, including lymphatic mapping for breast cancer, must be done and overseen by the medical community in a responsible way to ensure that the procedures are performed correctly. This study addresses the issues of adequacy of training and certification of surgeons performing lymphatic mapping. Ensuring quality in surgical care requires outcomes measures that are described in this study. STUDY DESIGN: Sixteen surgeons performed lymphatic mapping in 2,255 patients with breast cancer using a combination blue dye and Tc99m-labeled sulfur colloid to identify the sentinel lymph nodes (SLNs). All participants were trained in a 2-day CME-accredited course. The Cox learning curve model (total number of mapping failures/total number of mapping cases) for a consecutive series of lymphatic mapping cases is described. The relationship of the Surgical Volume Index, the cases performed in a 30-day period, to the failure rate for each surgeon was modeled as a logistic regression curve (y = e(a+bx)/[1 + e(a+bx)]). RESULTS: Surgeons performing less than three SLN biopsies per month had an average success rate of 86.23% +/- 8.30%. Surgeons performing three to six SLN biopsies per month had a success rate of 88.73% +/- 6.36%. Surgeons performing more than six SLN biopsies per month had a success rate of 97.81% +/- 0.44%. CONCLUSIONS: This experience defines a learning curve for lymphatic mapping in breast cancer patients. Data suggest that increased volumes lead to decreased failure rates. These data provide surgeons performing SLN biopsy with a new paradigm for assessing their skill and adequacy of training and describes the relationship between volume of cases performed and success rate of SLN detection.

Breast Neoplasms↗

PubMed2004

Learning curve for the two-incision total hip replacement.

Recently there has been increased interest in doing total hip replacement through small incisions. One such technique is the two-incision approach. After initial investigations into its feasibility, Zimmer developed a training program for surgeons interested in doing the so called MIS 2-Incision Hip Procedure. An "index case" study was initiated to track the early experiences of trained surgeons, which includes 159 surgeons who have completed such training and recorded data on their initial cases. The purpose of this report is to present the data available from this index case study regarding the process of developing proficiency with the two-incision total hip replacement. We found a significant decrease in the mean operative time and fluoroscopy time from the first to tenth case. Key complications did not show a systematic decrease as a function of case number for the first ten cases. Clarification of the entire learning curve for this technique requires further investigation but may last beyond case ten for many surgeons. In addition, data from this study suggests that patient characteristics and surgeon experience have a significant effect on the prevalence of complications with the two-incision technique. The evolution of minimally invasive joint replacement is clearly in its infancy. Complication rates and the demonstrated learning curve may be altered by changes in training and surgical techniques.

Adult↗

PubMed2005

Initial experience with eversion carotid endarterectomy: absence of a learning curve for the first 100 patients.

OBJECTIVE: Eversion carotid endarterectomy (CEA) has been touted as superior to standard CEA with patch closure because of allegedly lower restenosis rates and greater technical ease of performance. The purpose of this study was to evaluate the early experience of one vascular surgeon beginning to use this technique. METHODS: This was a retrospective study in an academic vascular surgical practice. The first 100 patients undergoing CEA via the eversion technique were compared with 100 contemporaneous patients who had standard CEA with patch closure. Residual (first examination within 3 months) or recurrent postoperative duplex scan stenosis, perioperative neurologic deficit, and mortality were analyzed by cumulative sum failure and Kaplan-Meier life-table analysis. RESULTS: Operative indications were not significantly different between eversion and standard CEA patients (63% vs 60% asymptomatic, 10% vs 7% stroke, 4% vs 5% amaurosis, and 23% vs 28% transient ischemia). Intraoperative shunting was more commonly used during eversion CEA (87% vs 59%; P < .01). Perioperative neurologic deficits included amaurosis (n = 1) after eversion CEA and transient cerebral ischemia (n = 1) and retinal infarction (n = 1) after standard CEA, with one cardiac death each. By 36 months, one other patient in each group had experienced a transient ischemic event, but there were no strokes. Four carotids occluded within 36 months of eversion CEA, compared with one occlusion after standard CEA (not significant). Patients undergoing eversion CEA showed no difference in critical (>80%) residual or recurrent stenosis rates. However, after eversion CEA, a greater degree of greater than 50% recurrent stenosis was observed at 36 months (38% vs 6%; P < .001) despite similar residual stenosis rates. Cumulative sum failure analysis showed no plateau among patients undergoing eversion CEA, thus indicating the absence of a learning curve, at least within the first 100 patients. CONCLUSIONS: Despite enthusiasm by advocates for eversion CEA, the recurrent greater than 50% stenosis rate remained high for the first 100 patients who underwent this technique, with no evidence of a learning curve. This observation implies that vascular surgeons considering adoption of this technique should monitor their own early results carefully.

Aged↗

PubMedDate not supplied

Defining the learning curve for paramedic student endotracheal intubation.

BACKGROUND: Proficiency in endotracheal intubation (ETI) is assumed to improve primarily with accumulated experience on live patients. While the National Standard Paramedic Curriculum recommends that paramedic students (PSs) perform at least five live ETIs, these training opportunities are limited. OBJECTIVE: To evaluate the effects of cumulative live ETI experience, elapsed duration of training, and clinical setting on PS ETI proficiency. METHODS: The authors used longitudinal, multicenter data from 60 paramedic training programs over a two-year period. The PSs reported outcomes (success/failure) for all live ETIs attempted in the operating room (OR), the emergency department (ED), the intensive care unit (ICU), and other hospital or prehospital settings. Fixed-effects logistic regression was used to model up to 30 consecutive ETI efforts by each PS, accounting for per-PS clustering. For each patient, the authors evaluated the association between ETI success and the PS's cumulative number of ETIs, adjusted for clinical setting, elapsed number of days from the first ETI encounter, and the interaction (cumulative ETIs x elapsed days). Predicted probability plots were constructed depicting the "learning curve" overall and for each clinical setting. Results. Between one and 74 ETIs (median 7; IQR 4-12) were performed by each of 802 PSs. Of 7,635 ETIs, 6,464 (87.4%) were successful. Stratified by clinical setting, 6,311 (82.7%) ETIs were performed in the OR, 271 (3.6%) in the ED, 64 (0.8%) in the ICU, 86 (1.1%) in other in-hospital settings, and 903 (11.8%) in the prehospital setting. For the 7,398 ETIs included in the multivariate analysis, cumulative number of ETI was associated with increased adjusted odds of ETI success (odds ratio 1.067 per ETI; 95% CI: 1.044-1.091). ETI learning curves were steepest for the ICU and prehospital settings but lower than for other clinical settings. CONCLUSIONS: Paramedic student ETI success improves with accumulated live experience but appears to vary across different clinical settings. Strategies for PS airway education must consider the volume of live ETIs as well as the clinical settings used for ETI training.

Allied Health Personnel↗

PubMed1996

Learning curve for radiofrequency catheter ablation in pediatrics at a single institution.

We examined the learning curve for radiofrequency ablation in pediatrics at a single institution. The first 146 cases were retrospectively reviewed, including patients < or = 21 years old with a single tachycardia diagnosis who were undergoing radiofrequency ablation for the first time. Data regarding demographics, electrophysiologic properties of the tachycardia, and procedural characteristics were tabulated. Data were then analyzed for evidence of association between these characteristics, success, and experience. Results revealed that success rates improved significantly with experience, reaching 85% success for all cases after < 100 cases attempted. Success for accessory pathway tachycardias alone reached > 93%. The number of cases of nonpathway tachycardias undertaken significantly increased as experience was gained. Fluoroscopy time improved to 34 +/- 27 minutes after < 100 cases. In conclusion, as experience was gained, (1) success rates showed a steep improvement; (2) the population undergoing radiofrequency ablation clearly shifted to include more difficult diagnoses; and (3) fluoroscopy time significantly decreased.

Adolescent↗

PubMed2006

Learning curve analysis of a patient lift-assist device.

One of the challenges facing ergonomists in the implementation of an ergonomic solution is addressing the concerns related to their impact on productivity. The focus of the current study was to (1) apply standard learning curve analysis to the learning that takes place as an individual works with a patient handling device and (2) compare the effects of two different training protocols on measures of learning. Eighteen subjects completed 11 replications of a patient transfer task after participating in either an "interactive" training protocol or "see-one-do-one" training protocol. The results show that the learning rate for this task was 83% with no difference as a function of training protocol. The results do indicate that the effect of Training Method was significant (p<0.05) for time to complete the first patient lift task (370s for the interactive training vs. 475s for see-one-do-one training). The results of the analysis of the survey data supported the objective results in that the only measure that was responsive to training type (p<0.05) was related to comfort level in performing the patient lift task for the first time. The results emphasize the importance in considering learning when introducing an intervention in the workplace, and showed that in this instance, training type had an immediate impact on productivity, but that this effect diminished over time.

Adult↗

PubMed1998

Laparoscopic splenectomy: lessons from the learning curve.

OBJECTIVE: Initial reports suggest that laparoscopic splenectomy is a difficult procedure with a steep learning curve and limited scope. The objective of this study was to review various approaches to simplify the operation. DESIGN: A descriptive study of a prospective database. SETTING: A tertiary care teaching hospital. PATIENTS: Fifty-one consecutive patients, seen over a 4-year period, who underwent laparoscopic splenectomy (partial laparoscopic splenectomy in 1 patient) for a wide variety of disorders. INTERVENTIONS: Anterior and lateral surgical approaches to laparoscopic splenectomy and the selective use of preoperative splenic artery embolization. MAIN OUTCOME MEASURES: Blood loss, morbidity, mortality and rate of conversion to open splenectomy, operating time and postoperative hospital stay. RESULTS: The morbidity (11%), death rate (2%), and rate of conversion were low. The recovery rate of accessory spleens was high (24%). Average operating time (3 hours), postoperative stay (3 days) and volume of blood loss improved with time. CONCLUSIONS: Laparoscopic splenectomy is a reliable procedure for patients with spleens less than 20 cm long. For spleens 20 to 30 cm long, preoperative embolization is advisable, and the surgeon should be experienced. Laparoscopic splenectomy should not be performed for spleens more than 30 cm long. The lateral approach has eliminated most of the difficulty with this procedure for spleens less than 20 cm long (no embolization). The anterior approach is reserved for large spleens and partial laparoscopic splenectomy (with embolization).

Adolescent↗

PubMed1959

Artifacts in criterion-reference learning curves.

Explore the source record for details and available documents.

Artifacts↗

PubMed1986

[Transluminal coronary angioplasty: is a learning curve necessary?].

Transluminal coronary angioplasty is a complex technique, and a lesser percentage of success, or "learning curve", is reported in the initial experience of several investigators. Is reported here an initial series of 20 consecutive cases treated by coronary angioplasty for single vessel coronary disease with favourable results. After a meticulous medical treatment, coronary angioplasty was performed in the 20 cases with a "steerable" catheter and guide system and step-wise pressure inflations. In only 1 case (5%), with highly unstable clinical conditions and "unfavourable anatomy", the technique was followed by emergency aorto-coronary bypass and myocardial infarction. In 19 cases (95%) clinical and angiographic success was obtained, with a significant reduction of the mean measured coronary artery stenosis from 84.8 +/- 10.5% to a post-dilatation value of 15.6 +/- 10.5% (p less than 0.001). Coronary artery occlusion due to spasm or thrombosis or coronary dissection were never observed. This favourable series demonstrates that nowadays with the improved technology and with a scrupulous pharmacological protocol transluminal coronary angioplasty can be performed with a low incidence of complications and excellent results, further assessing its high potential in the treatment of ischemic coronary artery disease.

Adult↗

PubMed1994

Complications of limb lengthening. A learning curve.

Major complication rates during limb lengthening were plotted in a consecutive series to produce a learning curve. All unwanted events during and after treatment were considered complications, and graded as minor, serious, and severe. All serious and severe complications were considered major. A novel system was used to classify the preoperative severity of each deformity. One-hundred ten patients had 140 bone segments lengthened between 2.2 cm and 10.5 cm, with a mean of 4.4 cm. Three methods were used in lengthening: the Wagner method in 22 patients, the DeBastiani method in 34 patients, and the Ilizarov method in 84 patients. Ninety-eight complications categorized as serious or severe occurred, for a total major complication rate of 72%. The percentage of major complications began to drop after 30 lengthenings to a current rate of 25%. Major complications were frequent in patients with more severe deformities, particularly in those whose cases occurred early in the series. Bone healing complications were high (72%) in the Wagner segments but were also high (80%) in the first ten patients treated with the DeBastiani technique. The first ten Ilizarov patients, who were treated later in the series, had a 40% rate of bone-healing complications. The current rate of major complications is 13% for those patients treated with DeBastiani's method and 33% for those patients treated with Ilizarov's method. This difference in complication rates appears to relate to the severity of the deformity, rather than the device used. There was a significant decrease in complications as experience was gained. Directed formal study and surgical instruction should help diminish these complications.

Adolescent↗

PubMed2005

Exploring the learning curve, pathological outcomes and perioperative morbidity of laparoscopic partial nephrectomy performed for renal mass.

PURPOSE: We investigated the learning curve, pathological results and perioperative morbidity of laparoscopic partial nephrectomy (LPN). MATERIALS AND METHODS: The records of all LPN cases at our institution between January 1999 and March 2004 were reviewed. Of 223 cases 217 (97.3%) were performed for an enhancing renal mass. RESULTS: Mean tumor size was 2.6 cm (range 1 to 10) and 95.4% of patients had a normal contralateral kidney. Transient vascular control was performed in 75.1% of cases. Mean operative time (186 minutes) decreased with surgeon experience (p = 0.003) but was independent of tumor size (p = 0.964). Mean warm ischemia time (27.6 minutes) depended on tumor size (p = 0.005) but not on experience (0.964). Mean blood loss was 385 cc and the perioperative transfusion rate was 6.9%. Postoperative complications occurred in 23 cases (10.6%) with the most common being ileus (1.8%), bleeding (1.8%) and urinary leakage (1.4%). Although the mean serum creatinine change after LPN was a function of tumor size (p <0.001), it was clinically insignificant (0.13 mg/dl). No significant relationship was observed between warm ischemia time and creatinine change (p = 0.262). The final pathological evaluation revealed renal cell carcinoma in 144 patients (66.4%) and the overall positive margin rate was 3.5%. Only 2 renal cell carcinoma recurrences in the operated kidney (1.4%) were identified (mean followup +/- SD 24 +/- 12 months). CONCLUSIONS: LPN is an effective approach for treating small renal masses with low perioperative morbidity. Contrary to previous reports, more than 30% of the enhancing renal lesions excised in this series were found to be benign on final pathological evaluation.

Adult↗

PubMed2001

Universal learning curves of support vector machines.

Using methods of statistical physics, we investigate the role of model complexity in learning with support vector machines (SVMs), which are an important alternative to neural networks. We show the advantages of using SVMs with kernels of infinite complexity on noisy target rules, which, in contrast to common theoretical beliefs, are found to achieve optimal generalization error although the training error does not converge to the generalization error. Moreover, we find a universal asymptotics of the learning curves which depend only on the target rule but not on the SVM kernel.

Journal Article↗

PubMed1997

Overcoming the learning curve in microvascular head and neck reconstruction.

BACKGROUND: It is widely accepted that most microvascular reconstructive surgeons experience a learning curve. A compilation of 6 series of microvascular surgery reported in the literature revealed that the average rate of successful free flap transfer rose from 79% to 96% as the surgeons gained clinical experience. OBJECTIVE: To review the collective experience of 3 otolaryngologist-head and neck surgeons performing free flaps during their first year of clinical practice after completion of postgraduate training. DESIGN: A multi-institutional retrospective case series. SETTING: Three academic tertiary care otolaryngology-head and neck surgery programs. PATIENTS: Eighty-one microvascular free flaps were performed in patients undergoing surgical reconstruction of head and neck defects during a 1-year period. INTERVENTIONS: Free flap selection was based on specific defect characteristics. Radial forearm, fibula, and rectus abdominis flaps together accounted for 90% of the donor sites selected. MAIN OUTCOME MEASURE: Reported incidence of partial or complete free flap necrosis. RESULTS: There were 2 perioperative deaths. Among the surviving patients, there were 2 cases of complete flap failure, for an overall success rate of 97.5%. There were 2 additional cases of partial flap necrosis (2.5%) that were related to errors in flap insetting. CONCLUSION: The availability of high-quality postgraduate training combined with the judicious selection of free flaps that offer long vascular pedicles and large diameter vessels can allow junior microvascular head and neck surgeons to achieve free flap survival rates that are comparable with those reported by experienced microvascular surgeons.

Clinical Competence↗

PubMed2005

Learning curve of laparoscopy-assisted distal gastrectomy with systemic lymphadenectomy for early gastric cancer.

AIM: To evaluate the nature of the "learning curve" for laparoscopy-assisted distal gastrectomy (LADG) with systemic lymphadenectomy for early gastric cancer. METHODS: The data of 90 consecutive patients with early gastric cancer who underwent LADG with systemic lymphadenectomy between April 2003 and November 2004 were reviewed. The 90 patients were divided into 9 sequential groups of 10 cases in each group and the average operative time of these 9 groups were determined. Other learning indicators, such as transfusion requirements, conversion rates to open surgery, postoperative complication, time to first flatus, and postoperative hospital stay, were evaluated. RESULTS: After the first 10 LADGs, the operative time reached its first plateau (230-240 min/operation) and then reached a second plateau (<200 min/operation) for the final 30 cases. Although a significant improvement in the operative time was noted after the first 50 cases, there were no significant differences in transfusion requirements, conversion rates to open surgery, postoperative complications, time to first flatus, or postoperative hospital stay between the groups. CONCLUSION: Based on operative time analysis, this study show that experience of 50 cases of LADG with systemic lymphadenectomy for early gastric cancer is required to achieve optimum proficiency.

Adult↗

PubMedDate not supplied

[Is there a learning curve for laparoscopic cholecystectomy ?].

UNLABELLED: The use of laparoscopic surgery it is growing rapidly in Romania. We have tried to find if a learning curve for laparoscopic cholecystectomy exists and we have evaluated our training program to insure the quality of health care. METHODS: There where analyzed 2585 procedures performed by 22 surgeons. The relationship between operative incidents/accidents and laparoscopic experience was evaluated. With a regression model we have find the tendency of these relationship. RESULTS: Surgeons appear to learn this procedure rapidly. CONCLUSIONS: Training curses with hands-on experience with animal models and proctoring from an experienced laparoscopist at the first 30 operations is needed, for each individual surgeon, to insure the quality of health care.

Animals↗

PubMed1994

Training in laparoscopic cholecystectomy. Quantifying the learning curve.

There is no clear consensus on the best way to train general surgeons to perform laparoscopic cholecystectomy (LC). We attempted to quantify the "learning curve" for 86 surgeons attending eight consecutive 3-day, three-pig courses in LC. Each step of the operation was scored by the instructor for successful performance: Uncomplicated pneumoperitoneum (p), cystic duct and artery dissection (cd), artery and duct clipping (cc), operative cholangiography (oc), gallbladder dissection without holes (gd), liver bed hemostasis (h), gallbladder removal in one piece (i), and no abdominal organ injury (in). As well, operative time, method of dissection, and contact Nd: YAG or electrocautery were recorded. The percentage of students successfully completing each task for the first and third pigs on which they acted as surgeon was as follows: [table: see text] The operative time for the first and third pigs was 1.3 +/- 0.56 and 0.70 +/- 0.34 (mean +/- SD) h, respectively (P < 0.01). When students were trained with the contact Nd: YAG laser there was more blood loss than with electrosurgery (P < 0.001). Statistically significant improvement could only be demonstrated in the most difficult task, gallbladder dissection without perforation, but that task had not been mastered by the end of 3 days. The flat portion of the laparoscopic cholecystectomy "training curve" had not been reached by the end of the program.

Animals↗

PubMed1988

Experience with potency preservation during radical prostatectomy. Significance of learning curve.

Potency preservation after radical prostatectomy is relatively new. The efficacy of this procedure has not been widely documented. Twenty-four patients with full potency underwent nerve-sparing radical prostatectomy. A total of 12 patients retained potency after surgery. Analysis of data reveals there is a learning curve in doing this procedure, and once the initial learning phase is over good results can be obtained in a select group of patients.

Aged↗