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 163 records · Page 9Linked to original sources

PubMed1994

What is the learning curve for laparoscopic appendectomy?

When contemplating converting from open to laparoscopic appendectomy, a prudent surgeon should consider the anticipated learning curve. To evaluate this we reviewed our experience with 20 sequential patients representing this transition. We found the learning curve was brief and did not compromise clinical results. A reduction in hospitalization time without a rise in total hospital costs should encourage the experienced laparoscopic surgeon to consider laparoscopic appendectomy as a viable alternative to standard laparotomy in the resection of the acutely inflamed appendix.

Acute Disease↗

PubMed2004

Defining the learning curve for laparoscopic splenectomy for immune thrombocytopenia purpura.

BACKGROUND: The current study was undertaken to define the learning curve for laparoscopic splenectomy (LS) in patients with immune thrombocytopenic purpura (ITP). METHODS: The data of 50 patients who underwent LS for ITP between March 1996 and February 2003 were reviewed. Patients were divided into sequential groups of 10. Operative time, estimated blood loss, conversion to open procedure, length of stay (LOS), time to oral intake, complications, and mortality rates were analyzed. RESULTS: The mean OR time in the 3rd, 4th, and 5th groups of 10 were significantly shorter than the 1st and 2nd groups of 10. There were no significant differences in estimated blood loss, LOS, or time to oral intake between the groups. Three conversions to open splenectomy occurred; one each in the 2nd, 3rd, and 4th groups of 10. Complications were evenly distributed between groups. There were no deaths. CONCLUSION: The learning curve for LS in patients with ITP is a minimum of 20 cases.

Adult↗

PubMed2000

Institutional and individual learning curves for focused abdominal ultrasound for trauma: cumulative sum analysis.

OBJECTIVE: To evaluate both institutional and individual learning curves with focused abdominal ultrasound for trauma (FAST) by analyzing the incidence of diagnostic inaccuracies as a function of examiner experience for a group of trauma surgeons performing the study in the setting of an urban level I trauma center. SUMMARY BACKGROUND DATA: Trauma surgeons are routinely using FAST to evaluate patients with blunt trauma for hemoperitoneum. The volume of experience required for practicing trauma surgeons to be able to perform this examination with a reproducible level of accuracy has not been fully defined. METHODS: The authors reviewed prospectively gathered data for all patients undergoing FAST for blunt trauma during a 30-month period. All FAST interpretations were validated by at least one of four methods: computed tomography, diagnostic peritoneal lavage, celiotomy, or serial clinical evaluations. Cumulative sum (CUSUM) analysis was used to describe the learning curves for each individual surgeon at target accuracy rates of 85%, 90%, and 95% and for the institution as a whole at target examination accuracy rates of 85%, 90%, 95%, and 98%. RESULTS: Five trauma surgeons performed 546 FAST examinations during the study period. CUSUM analysis of the aggregate experience revealed that the examiners as a group exceeded 90% accuracy at the outset of clinical examination. The level of accuracy did not improve with either increased frequency of performance or total examination experience. The accuracy rates observed for each trauma surgeon ranged from 87% to 98%. The surgeon with the highest accuracy rate performed the fewest examinations. No practitioner demonstrated improved accuracy with increased experience. CONCLUSIONS: Trauma surgeons who are newly trained in the use of FAST can achieve an overall accuracy rate of at least 90% from the outset of clinical experience with this modality. Interexaminer variations in accuracy rates, which are observed above this level of performance, are probably related more to issues surrounding patient selection and inherent limitations of the examination in certain populations than to practitioner errors in the performance or interpretation of the study.

Abdominal Injuries↗

PubMed2005

Learning curve of hand-assisted retroperitoneoscopic nephrectomy in less-experienced laparoscopic surgeons.

AIM: To evaluate the learning curve of hand-assisted retroperitoneoscopic nephrectomy (HALS) performed by less-experienced surgeons. METHODS: The operative records of 166 patients, including 103 with renal tumors and 63 with renal pelvic or ureteral tumors, who underwent HALS performed by 18 less-experienced urologists were reviewed. RESULTS: The insufflation time in the first four cases was significantly longer than that in the sixteenth and later cases. The insufflation time in cases 5-10 was 14-24 min longer than that in the cases 16 onward, although the differences were not significant. The estimated blood loss did not differ in each group of cases. The complication rate in early cases, in which the operators' experience was five cases or less, was 6% (4/71), while that in later cases was also 7% (7/95). In the analysis of the learning curve of a single surgeon who performed 57 procedures, the insufflation time in cases 1-5 was significantly longer than in cases 41-57. The insufflation times in cases 5-10 were 45 min longer than those in cases 41-57, although the difference was not significant. The estimated blood loss did not differ in each group of cases. Complications did not seem related to operation experience. CONCLUSION: In HALS, 5-10 cases were necessary for less-experienced urologists to gain average operating skills for this procedure. It may be reasonable for less-experienced surgeons to begin standard laparoscopic procedures after experiencing 10 cases of the present procedure.

Adult↗

PubMed2006

Team-based approach reduces learning curve in robot-assisted laparoscopic radical prostatectomy.

AIM: We assessed the team approach in reducing the learning curve during our 2-year experience transiting from open to robot-assisted laparoscopic radical prostatectomy (rLRP). METHODS: A team of three urologists progressed through assistant phase to console phase to obtain competency in robotic prostatectomy. One hundred patients underwent rLRP by this team using the da Vinci robotic surgical system from 1 February 2003 to 15 May 2005. RESULTS: The immediate perioperative outcome was divided into three corresponding time frames and the results demonstrated gradual improvement in outcome parameters. The mean set-up time and dissection time were 24+/-14 min and 182+/-52 min, respectively. The mean perioperative blood loss was 272+/-240 mL, and 7% of patients (n=7) required blood transfusion. The mean duration of bladder catheterization was 8.4+/-4.1 days, and mean hospital stay was 2.9+/-1.6 days. There was no perioperative mortality or conversion to open radical prostatectomy. Major complications (4%) included urethrovesical leak requiring re-operation, postoperative cerebrovascular accident, and transient ureteric obstruction. Minor complications (7%) included minor urethrovesical leak, bladder neck stenosis, and urinary tract infection. Mean follow up was 6.6+/-5.0 months. Pathological assessment showed pT2 disease in 55% and pT3 in 45% of specimens. CONCLUSIONS: A team-based approach to robot-assisted LRP helped to reduce the learning curve of the procedure for individual surgeons and continued to show significantly lower perioperative blood loss, transfusion requirements and postoperative pain compared to open radical retropubic prostatectomy.

Follow-Up Studies↗

PubMed2005

The laparoscopic nephrectomy learning curve: a single centre's development of a de novo practice.

OBJECTIVE: There has been a dramatic increase in the interest and practice of laparoscopic urology, with nephrectomy having become the commonest laparoscopic urological procedure. Compared with open nephrectomy, it results in reduced morbidity and shorter convalescence times while maintaining oncological safety. However, while these results predominately stem from institutions with well developed laparoscopic programmes, little is known about the results in centres that have newly adopted this technique. The introduction of a laparoscopic urological service at the Royal Hallamshire Hospital provided an opportunity to study these factors. METHODS: Since the appointment in October 2000 of a urological surgeon (N Oakley) to develop the laparoscopic service, there have been over 200 laparoscopic procedures including 121 nephrectomies performed at this centre. Full details were collected for each of these cases, and in addition, compared with retrospective data for 50 open nephrectomies performed during the same time period. RESULTS: With increased operator experience the median operative duration, complication, transfusion, and conversion rates significantly improved. While a learning curve was evident, the overall operative complication (9%) and conversion rates (6%) were low, in addition to patient morbidity (16.5%) and mortality (0%) rates, showing that this learning curve had no deleterious effects upon patient care. The median hospital stay was four days, which reduced to three with experience and was significantly shorter than for open nephrectomy at this institution (p = 0.001). CONCLUSIONS: The development of a successful laparoscopic programme can be achieved with a comparatively short learning curve and without detriment to the patient provided the necessary steps are observed.

Carcinoma, Renal Cell↗

PubMed2005

EUS-guided FNA of solid pancreatic masses: a learning curve with 300 consecutive procedures.

BACKGROUND: The objective of our study was to assess a single operator's learning curve with regard to the number of passes, the diagnostic accuracy, and the complications associated with EUS-guided FNA (EUS-FNA) of solid pancreatic masses. METHODS: The number of passes, the diagnostic accuracy, and the complication rate were prospectively evaluated in 300 consecutive EUS-FNA of solid pancreatic masses performed by a single endosonographer over a 3-year period. The procedures were placed into 3 groups, which contained 100 procedures each. The endosonographer had undergone a third-tier EUS fellowship and had performed 45 supervised pancreatic EUS-FNA during his training. RESULTS: Of the 300 EUS-FNA performed (median age 63 years, 64% men), no statistically significant differences among the 3 groups with regard to age, gender, race, location, or size of the mass were found. Diagnostic accuracy of the EUS-FNA procedure was similar over time (Group 1, 92%; Group 2, 92%; Group 3, 95%). Median number of passes showed a decreasing trend over the 3-year study period, despite an increasing trend of the number of procedures performed (r = -0.14, p = 0.42). The median number of passes was lower for Group 2 (median, 3; p = 0.02) and Group 3 (median, 3; p = 0.003) compared with Group 1 (median, 4). Group 3 (7/100, 7%) was less likely to encounter complications compared with Group 1 (13/100, 13%; p = 0.24) and Group 2 (18/100, 18%; p = 0.03). Frequency of serious complications was similar across the 3 groups (1%-3%). CONCLUSIONS: With adequate third-tier training, a newly developed EUS program can achieve safe and accurate results of EUS-FNA of the pancreas. The learning curve, however, needs to continue after the fellowship, because more procedures are needed for one to gain proficiency and efficiency with EUS-FNA.

Adult↗

PubMed2003

Averaging learning curves across and within participants.

We examine recent concerns that averaged learning curves can present a distorted picture of individual learning. Analyses of practice curve data from a range of paradigms demonstrate that such concerns are well founded for fits of power and exponential functions when the arithmetic average is computed over participants. We also demonstrate that geometric averaging over participants does not, in general, avoid distortion. By contrast, we show that block averages of individual curves and similar smoothing techniques cause little or no distortion of functional form, while still providing the noise reduction benefits that motivate the use of averages. Our analyses are concerned mainly with the effects of averaging on the fit of exponential and power functions, but we also define general conditions that must be met by any set of functions to avoid distortion from averaging.

Algorithms↗

PubMed2003

Analysis of the learning curve in telerobotic, beating heart coronary artery bypass grafting: a 90 patient experience.

BACKGROUND: Recent articles have commented on the "learning curve" in robotic-assisted coronary artery bypass grafting. We systematically studied this phenomenon using standard statistical and cumulative sum (CUSUM) failure methods. METHODS: Ninety patients underwent internal thoracic artery (ITA) takedown and an attempt at ITA to coronary bypass on the beating heart using the Zeus telerobotic system from September 1999 to December 2001. The rates of mortality and 11 predefined major complications were compared in five quintiles of 18 consecutive patients each and a CUSUM curve was generated for the entire cohort. RESULTS: All patients but one underwent successful endoscopic ITA takedown. Thirteen patients had a totally endoscopic anastomosis, whereas in 61 a small mini-thoracotomy or mini-sternotomy was used. Sixteen patients (17.8%) were converted electively to a sternotomy: 11 patients underwent off-pump and 5 patients on-pump surgery. There were no deaths; 13 patients (14.4%) incurred one or more of the 11 major complication(s), including 5, 1, 2, 3, and 2 in each of the five quintiles (p = 0.39). Standard statistical analyses identified a significant decrease in operating room time (p < 0.0001), as well as a decrease in the incidence of an occluded graft or wrong vessel grafted from quintiles 1 to 5 (p = 0.03). On CUSUM analysis, the failure curve was steep for the first 18 to 20 patients, before moderating its slope for the remainder of the experience. CONCLUSIONS: Robotic ITA to coronary bypass on the beating heart has a moderately steep learning curve, which is mitigated by further experience. CUSUM analysis complimented standard statistical methods in detecting a cluster of suboptimal results during the early experience with this procedure.

Clinical Competence↗

PubMed1998

Early experience and learning curve associated with laparoscopic Nissen fundoplication.

BACKGROUND: Laparoscopic approach for hiatal hernia repair is relatively new. Information on the learning curve is limited. METHODS: From January 1994 to September 1996, 280 patients underwent antireflux surgery at our institution. A laparoscopic repair was attempted in 60 patients (21.4%). There were 38 men and 22 women. Median age was 49 years (range 21 to 78 years). Indications for operation were gastroesophageal reflux in 59 patients and a large paraesophageal hernia in one. A Nissen fundoplication was performed in all patients; 53 (88.3%) had concomitant hiatal hernia repair. RESULTS: In eight patients (13.3%) the operation was converted to an open procedure. Median operative time for the 52 patients who had laparoscopic repair was 215 minutes (range 104 to 320 minutes). There were no deaths. Complications occurred in five patients (9.6%). Median hospitalization was 2 days (range 1 to 5 days). Median operative time and median hospitalization were significantly longer in the first 26 patients than in the subsequent 25 patients (248 vs 203 minutes and 2 days vs 1 day, respectively; p = 0.03). Seven of the first 30 patients (23.3%) required laparotomy as compared with two of the second 30 (6.7%) (p = 0.07). Follow-up in the 51 patients who had laparoscopic fundoplication for reflux was complete in 50 (98.0%) and ranged from 7 to 38 months (median 13 months). Functional results were classified as excellent in 34 patients (68.0%), good in 6 (12.0%), fair in 7 (14.0%), and poor in 3 (6.0%). Three patients were reoperated on for recurrent reflux symptoms at 5, 5, and 11 months. CONCLUSIONS: We conclude that laparoscopic Nissen fundoplication can be performed safely. The operative time, hospitalization, and conversion rate to laparotomy are higher during the early part of the experience, but all are reduced after the learning curve.

Adult↗

PubMed1993

Phacoemulsification during the learning curve: risk/benefit analysis.

To assess prospectively the complications and outcomes in a single-surgeon series during the phacoemulsification learning curve a prospective analysis of 400 phacoemulsification procedures in 358 patients was carried out. The main outcome measures were capsular tear, vitreous and nuclear loss, best corrected post-operative visual acuity and refractive cylinder. Capsular tears occurred in 6.3% of phacoemulsification procedures, with vitreous loss in 1.5%. One nucleus was lost into the vitreous. Best corrected visual acuity, including pre-existing pathology, was 6/9 or better in 83.6% of eyes. There was 1 dioptre or less change of astigmatism from pre-operative to 6 weeks in 91% of eyes. It is concluded that phacoemulsification with careful patient selection can be a safe procedure even during the learning curve.

Aged↗

PubMed1995

Laparoscopic-assisted colectomy. The learning curve.

One hundred fifty consecutive laparoscopic-assisted colectomies performed by a surgical team were analyzed in an attempt to define a learning curve. These colectomies performed by the Norfolk Surgical Group over a 24-month period, were divided chronologically into six groups of 25 patients each. The groups were then compared to determine if any improvement in length of procedure, complication rate, conversion rate, or length of stay developed as experience increased. Colon cancer and diverticular disease were the most common indications for surgery in all groups. Right hemicolectomy, left colectomy, and low anterior resection accounted for the majority of procedures in all groups. A significant decrease in mean operative time, from 250 min to 156 min over the first 35-50 cases was observed before leveling off at approximately 140 min for the remaining group. Intraoperative complications were low in all groups (range zero to two) and did not show any trend. There was no statistically significant difference in the conversion rate (23.3% overall) among the six groups. Length of stay decreased from 6 days in the first two groups to 5 days in the last four groups, although the difference was not statistically significant. The learning curve for laparoscopic-assisted colectomies is longer than appreciated by many surgeons, requiring as many as 35-50 procedures to decrease operative time to baseline. Complications can be kept at an acceptably low level while on the curve if a cautious approach is taken and the surgeon realizes that a prolonged operative time is not only acceptable, but appropriate during this long learning process. A conversion rate of 20-25% at any phase of the learning process may in fact represent a limitation of current technology. When combined with a low complication rate it may be the sign of a careful surgeon.

Aged↗

PubMed2003

The learning curve on the Xitact LS 500 laparoscopy simulator: profiles of performance.

BACKGROUND: This study assesses the acquisition of skill and the learning curve associated with the performance of the clip-and-cut task on the Xitact LS 500 virtual reality (VR) simulator in laparoscopic cholecystectomy. METHODS: A group of 33 residents and interns with no previous laparoscopic experience participated in the study. All participants received a 1-h familiarization tour on the simulator. Thirty participants completed a full course of 30 simulation runs over 3 days (10 runs per day). The outcome parameters were a previously validated sum-score and time to complete performance. RESULTS: Group demographics were similar. Of the participants who completed the full study, 16.7% appeared to have such a high level of innate psychomotor abilities that they were considered proficient in the task immediately after the initial familiarization tour. Most participants (63.3%) had a moderate level of innate abilities, and their performance improved through repetitive VR training. In our study, 20% of the participants had such a low level of innate abilities that they were unable to achieve an acceptable performance in our minimal-access surgery (MAS) simulation. CONCLUSIONS: Learning curves cannot be assessed by examining the repetitive training of only one person. There seem to be four different performance profiles, reflecting the fact that some people are more adept than others to be trained by MAS procedural VR simulation. For participants receptive to training--63.3% in this study--proficiency in the task occurs after approximately 25 simulative runs.

Adult↗

PubMed2005

A comparative clinical study of short-term results of laparoscopic surgery for rectal cancer during the learning curve.

OBJECTIVES: The aim of this study was to assess the results of laparoscopic surgery for rectal carcinoma (LSRC) during the learning curve throughout the introduction of this technique at our medical center. MATERIALS AND METHODS: From January 2003 to April 2004, 40 patients undergoing surgery were assigned to laparoscopic surgery group (LSG) (n=20) or conventional surgery group (CSG) (n=20). Data were prospectively collected to statistically analyze clinical, anatomopathological, and economic variables. RESULTS: Groups were comparable in age, sex, body mass index, American Society of Anesthesiologists score, surgical technique performed, tumor size and distance, Dukes' stage, and proportion of patients with previous abdominal surgery and radiotherapy. There was no difference in operative time. LSG blood loss was lower (p<.0001). LSG peristalsis and oral intake began earlier (p<.0001). LSG hospital stay was shorter (p<.0001). Intraoperative complications (10% LSG vs 15% CSG) and overall morbidity (35% LSG vs 45% CSG) were no different. LSG did not record any anastomotic leakages. Two patients (10%) were converted to open surgery. Regarding oncologic adequacy of resection, specimen length and number of nodes harvested were no different. LSG distal and radial resection margins were greater (p<.0001; p=.03). LSG operative costs were greater (p<.0001). However, CSG hospitalization costs were higher (p<.001). There was no overall difference (p=0.1). CONCLUSIONS: LSRC has been a reliable and efficient technique during the learning curve at our hospital.

Aged↗

PubMedDate not supplied

[Radiologic restoration of patency in arteriovenous fistulas and grafts for vascular access in hemodialysis: the learning curve].

OBJECTIVE: To demonstrate the importance of the learning curve in the restoration of patency in vascular accesses (native fistulas and grafts) that are "plugged" on reaching the vascular radiology suite. MATERIAL AND METHODS: We present our experience in restoring patency in 47 vascular accesses for hemodialysis (36 native fistulas and 11 grafts) that stopped functioning abruptly. In those cases in which the cause was stenosis, we dilated the vessel with an angioplasty balloon. If thrombotic material was present in the access, we tried using different techniques to treat the thrombus until manual aspiration using a catheter was decided on as the definitive technique in the last 20 cases. RESULTS: A total of 53 lesions were treated, 39 of which contained thrombotic material. The overall rate of success was 63.8% (30 accesses restored). The best results in the removal of thrombotic material were obtained by manual aspiration of the thrombus using a catheter (90% success). Overall patency rates at 6 and 12 months were 18 and 9%, respectively. At the end of the follow-up period, 16 (53%) of the 30 accesses restored were functioning. CONCLUSIONS: In our experience, the restoration of patency in fistulas or grafts for hemodialysis requires special learning on the part of the vascular radiologist. When thrombotic material is present, we believe that manual aspiration using a catheter is the technique that yields the best results and at a lower cost.

Adult↗

PubMed2006

Sub-Tenon block: a learning curve of 100 cases.

This study measures the learning curve for accomplishing sub-Tenon blocks for ophthalmic surgery applicable to anaesthetists skilled in peribulbar techniques. We defined criteria for a good block in terms of chemosis, subconjunctival haemorrhage, globe movement and the need for additional peribulbar block. The overall success rate, by our definitions, was 72% and 56% for the two operators. The overall requirement for an additional peribulbar block was 10%. The rate of additional blocks and reduction in globe movement reached a plateau after about 60 procedures for both operators. The rates of chemosis (6% and 12% overall) and subconjunctival haemorrhage (6% and 12% overall) did not trend with increased experience. The results applied to both a cataract and a vitreo-retinal surgery casemix.

Adolescent↗

PubMed2004

Detection of small joint synovitis by ultrasonography: the learning curve of rheumatologists.

BACKGROUND: Ultrasonography allows assessment of soft tissue structures and has become a valued tool for diagnosing synovitis. OBJECTIVE: To assess the learning curve for ultrasonography in evaluating synovitis of the small joints in rheumatoid arthritis. METHODS: Metacarpophalangeal (MCP), metatarsophalangeal (MTP), and proximal interphalangeal (PIP) joints were evaluated using ultrasonography (Esaote AU 5 Epi, linear probe 10-13 MHz) by four rheumatologists, the first being experienced (senior), the others having no (fellows 1 and 2) or little (fellow 3) experience in ultrasonography. For each fellow, the learning curve was divided into blocks. In each block the fellow examined five consecutive patients with the senior; then, blinded to the senior's results, two further patients alone (seven patients examined per block). For each evaluation, the MCP, PIP, and MTP joints were individually tagged as having synovitis or not. The ultrasonography results were compared between fellow and senior for the two last patients of each block, using proportions of agreement and kappa statistics. RESULTS: 70 patients were evaluated (seven practice patients, followed by nine blocks). For fellows 1 and 2, the proportions of agreement were respectively 42% and 47% (kappa = 0 and 0) at the first evaluation, and rose progressively to 82% and 82% (kappa = 0.63 and 0.62) at the ninth evaluation. For fellow 3, initially good results were followed by decreased accuracy. CONCLUSIONS: Detecting synovitis of the MCP, PIP, and MTP joints using ultrasonography can be done accurately by rheumatologists initially not experienced in this technique. At least 70 examinations were necessary to develop competence.

Adult↗

PubMed2000

Bile duct injury during laparoscopic cholecystectomy: myth or reality of the learning curve?

BACKGROUND: Bile duct injury (BDI) is a severe complication of laparoscopic cholecystectomy (LC) that is probably related to the effects of the learning curve. The aim of this prospective, institutional, and longitudinal study is to compare the incidence of BDI during LC in relation to the progressive experience of surgeons. METHODS: A total of 784 LC were examined during a 6-year period. They were divided into the following three consecutive groups: group A (1993-94), group B (1995-96), and group C (1997-98). Incidence and type of BDI, experience of the surgeon, intra- or postoperative diagnosis, treatment performed to repair the injury, and early and late morbidity and mortality were evaluated. RESULTS: The overall incidence of BDI was 1.4%. There were three cases of transection of the common bile duct, four partial lesions of the bile duct, and four cystic leakages. The number of BDI was maintained over the three different time periods; there were no statistical differences in the proportion of injuries among groups. Most BDI were incurred by experienced surgeons. In all, 36% of BDI were recognized intraoperatively. Hepaticojejunostomy, direct suture over a T-tube, and closure of the cystic stump were done to repair BDI. There was no additional morbidity or mortality in the patients with BDI. CONCLUSIONS: No relation was found between the experience of the surgeon and the number of BDI over the different periods of time. Therefore, BDI during LC cannot be attributed solely to the learning curve.

Adult↗