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PubMed2006

The learning curve in endoscopic pituitary surgery and our experience.

Experience is the important point in reduction of the complications and in the effectiveness of the surgical procedure in pituitary surgery. Endoscopic pituitary surgery differs from microscopic surgery, since it requires a steep learning curve for endoscopic skills. In this article, we evaluate our learning curve in two groups, as early and late experience. Purely endoscopic transsphenoidal operations were performed on 78 patients, which were retrospectively reviewed and grouped as early and late experience groups. We used the purely endoscopic endonasal approach to the sella that was performed via an anterior sphenoidotomy, without the use of a transsphenoidal retractor. All patients with adenomas were evaluated considering operation time, endocrinology, ophthalmology, total removal and, especially, modifications of standard technique. On the basis of the experience gained with the use of the endoscope in transphenoidal surgery over the years, modifications can be performed on the different phases of the endoscopic approach. Reviewing our cases in two groups of period due to our experience showed that the effectiveness of endoscopic surgery increases and operation time decreases. In our study, we identified a learning curve in endoscopic pituitary surgery.

Adenoma↗

PubMed2001

The learning curve and sentinel node biopsy.

BACKGROUND: The ability of sentinel node biopsy (SNB) to replace axillary node dissection for accurate breast cancer staging is absolutely dependent on the consistent and accurate determination and removal of the "true" sentinel node. There are a wide variety of variables that affect the ability of the physician to achieve this goal. One important and potentially controllable variable is physician training and competence to employ the available techniques successfully. There is a large diversity of opinion regarding the minimum number of cases required under supervision prior to independent utilization of the technique but there are data to support at least 20 cases done in conjunction with axillary dissection or under direct supervision. METHODS: Data from single institution and multicenter trials are reviewed and the learning curves are described. An overview of surgical education methods, testing, and credentialing is also addressed. RESULTS: A review of single institution series show that the false negative rate and identification rates vary considerably. In all cases where authors published a second series success rate improved compared with their initial series. Of the four multicenter trials only two can provide reliable learning curves and these have shown a decrease in the false negative rate to < or = 5% after 20 to 30 procedures are performed. CONCLUSIONS: There are data to show that there is a definite learning curve for SNB that cannot be ignored. It is possible that other factors, (ie, a skin injection with technetium-99, Sappeys plexus injection, and mentoring) could decrease this learning curve but until compelling evidence to suggest otherwise is available, surgeons should obtain a minimum experience of 20 cases.

Clinical Competence↗

PubMed2001

Institutional learning curve for sentinel node biopsy at a community teaching hospital.

Sentinel lymph node biopsy (SLB) is gaining popularity as an alternative to axillary lymph node dissection for breast cancer staging. Although publications have described the inherent learning curve few have analyzed actual performance in community hospitals. This study analyzes the institutional learning curve for SLB in a community teaching hospital without a formal sentinel node credentialing policy. We conducted an analysis of the initial 96 SLBs performed by 15 general surgeons over a 34-month period. The main outcomes were rate of identification of sentinel node and accuracy of SLB. Overall SLB was successful in identifying one or more sentinel nodes (mean = 2.2) in 73 per cent of attempted cases. There were marked differences in performance of individual surgeons; identification rates varied from 25 to 100 per cent. Only one surgeon performed more than 15 procedures during the study period. Nineteen of 21 cases with positive nodes were correctly characterized (sensitivity = 90.5%; 95% confidence interval = 76-100%; false negative rate = 9.5%). Our institutional learning curve was longer than high-volume individual experiences published in the literature, with a lower rate of sentinel node identification. SLB appears to be sensitive for detecting malignancy, but the small number of patients with positive nodes in our series limits our conclusions. The marked variability in individual surgeon performances and the slow rate of overall improvement in our institution suggest a need for a formalized policy for SLB training.

Breast Neoplasms↗

PubMed2005

The learning curve associated with laparoscopic pyloromyotomy.

BACKGROUND: Laparoscopic pyloromyotomy (LPM) for the treatment of infantile hypertrophic pyloric stenosis (HPS) has gained popularity in recent years. This study examines the learning curve associated with LPM. METHODS: We performed a retrospective analysis of patients undergoing LPM at a children's hospital between January 1, 1997 and June 30, 2003. Data including age, weight, complications, operative time, time to feeding, and length of postoperative stay were analyzed using the Student's ttest. RESULTS: A total of 51 patients underwent LPM during the study period. Patient characteristics were similar throughout the study period. Operative time ranged from 12 to 55 minutes (mean, 25 minutes). Mean operative time decreased significantly from 31+/-11 minutes for the first 15 patients, to 25+/-6 minutes for the second 15 patients, to 20+/-7 minutes for the last 15 patients (P<0.05). Operative times were erratic for the early cases but became more consistent over time, especially after 30 cases. Conversion to an open procedure was required in two patients. Complications included an umbilical port site wound dehiscence and readmission for persistent vomiting. There were no mucosal perforations. Time to ad lib feeding and postoperative length of stay did not change over time. CONCLUSION: LPM has a steep learning curve, especially for the first 15 patients. Operative time decreases and becomes more consistent after about 30 cases. Despite the learning curve, LPM can be performed safely and effectively without an increase in complications.

Clinical Competence↗

PubMed2003

Learning curves and impact of previous operative experience on performance on a virtual reality simulator to test laparoscopic surgical skills.

BACKGROUND: The study was carried out to analyze the learning rate for laparoscopic skills on a virtual reality training system and to establish whether the simulator was able to differentiate between surgeons with different laparoscopic experience. METHODS: Forty-one surgeons were divided into three groups according to their experience in laparoscopic surgery: masters (group 1, performed more than 100 cholecystectomies), intermediates (group 2, between 15 and 80 cholecystectomies), and beginners (group 3, fewer than 10 cholecystectomies) were included in the study. The participants were tested on the Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) 10 consecutive times within a 1-month period. Assessment of laparoscopic skills included time, errors, and economy of hand movement, measured by the simulator. RESULTS: The learning curves regarding time reached plateau after the second repetition for group 1, the fifth repetition for group 2, and the seventh repetition for group 3 (Friedman's tests P <0.05). Experienced surgeons did not improve their error or economy of movement scores (Friedman's tests, P >0.2) indicating the absence of a learning curve for these parameters. Group 2 error scores reached plateau after the first repetition, and group 3 after the fifth repetition. Group 2 improved their economy of movement score up to the third repetition and group 3 up to the sixth repetition (Friedman's tests, P <0.05). Experienced surgeons (group 1) demonstrated best performance parameters, followed by group 2 and group 3 (Mann-Whitney test P <0.05). CONCLUSIONS: Different learning curves existed for surgeons with different laparoscopic background. The familiarization rate on the simulator was proportional to the operative experience of the surgeons. Experienced surgeons demonstrated best laparoscopic performance on the simulator, followed by those with intermediate experience and the beginners. These differences indicate that the scoring system of MIST-VR is sensitive and specific to measuring skills relevant for laparoscopic surgery.

Clinical Competence↗

PubMed2000

Quantification of the learning curve for percutaneous dilatational tracheotomy.

OBJECTIVES/HYPOTHESIS: Although numerous investigators have reported a bedside percutaneous dilatational tracheotomy (PDT) complication incidence similar to that of standard operative tracheostomy, others have proposed a "learning curve" for PDT resulting in increased complications early in individual or institutional experience with this procedure. The objective of this investigation is to characterize and quantify the proposed learning curve for PDT. STUDY DESIGN: Prospective analysis of complication incidence for the first 100 PDT procedures performed in a local community hospital Department of General Surgery. METHODS: Demographic data, patient disease variables, and patient anatomic features, as well as perioperative, postoperative, and late complications, were recorded prospectively. Patients were divided into sequential cohorts of 20 and were evaluated for complications at regular intervals. RESULTS: Perioperative and late complication incidence was significantly higher in the first 20 patients who underwent PDT. However, postoperative complication incidence did not significantly vary with operator or institutional experience. In addition, patients with suboptimal anatomy were found to have a significantly increased complication incidence, independent of operator and institutional experience. CONCLUSIONS: Percutaneous dilational tracheotomy has an identifiable learning curve that is most prominent in the first 20 patients treated. Early experience with PDT should be obtained under controlled circumstances, ideally the operating suite. Although most complications occur during acquisition of early experience with PDT, certain life-threatening complications such as tube dislodgment or inability to complete procedure may occur even after extensive experience is obtained. Bedside PDT has an acceptable complication incidence, but any surgeon employing this technique must be prepared to perform immediate standard open tracheotomy to minimize potentially lethal complications of this elective procedure.

Adolescent↗

PubMed2003

Laparoscopic radical prostatectomy: decreasing the learning curve using a mentor initiated approach.

PURPOSE: Laparoscopic radical prostatectomy is being evaluated at several centers in the United States as a treatment option for localized prostate cancer. It is a technically difficult operation to perform with a steep learning curve. It has been stated that 50 procedures are necessary to satisfy the learning curve. To expedite performance and evaluation of laparoscopic radical prostatectomy a surgeon (mentor) who had performed 200 cases was invited to instruct a fellowship trained laparoscopist (trainee). MATERIALS AND METHODS: From March 2001 through September 2001 we performed 30 laparoscopic radical prostatectomies. The mentor performed the first 12 procedures with the trainee acting as assistant (group 1). The subsequent 18 procedures were performed by the trainee with the mentor acting as assistant (group 2). A final set of 20 procedures was performed by the trainee alone using 1 of 3 urological residents as the assistant (group 3). The transperitoneal approach was used and all suturing was intracorporeal. Preoperative data included prostate specific antigen, clinical stage, Gleason grade and median patient age. Intraoperative data included operative time, the blood loss/transfusion rate and intraoperative complications. Postoperative data included pathological stage, prostate specific antigen, the positive margin rate, catheter dwell time and hospital stay. When applicable, statistical significance was determined using the standard paired t test. RESULTS: There was no statistical difference in median operative time in groups 1 and 2 (248 and 258 minutes, respectively, p = 0.15). Similarly there was no difference in groups 2 (trainee and mentor assistant) and 3 (trainee alone) (p = 0.26). There was a difference in operative time in groups 1 and 3 (p = 0.04). Mean estimated blood loss was comparable in groups 1 to 3 and not statistically different (150, 250 and 250 cc, respectively, p = 0.15). Mean organ weight was also comparable (64, 59 and 55 gm., respectively). Hospital stay was 3 days in all groups. Catheter time decreased as confidence was gained with the procedure (range 6 to 33 days). Final pathological stage was compared among the 3 groups. There was an overall increase in positive margins in groups 1 to 3 (16%, 22% and 30%, respectively, p not significant). However, the positive margin rate for stage pT2 disease was similar at 15.5% for groups 1 and 2, and 14% for group 3. CONCLUSIONS: Laparoscopic radical prostatectomy is a technically challenging operation that is in the early stages of evolution and evaluation. We present an intensive, mentor initiated approach to decrease the learning curve and maintain outcomes.

Education, Medical, Continuing↗

PubMed2004

Overcoming the steep learning curve of laparoscopic radical prostatectomy: single-surgeon experience.

PURPOSE: To evaluate the influence of intensive laparoscopic skills training and self-critical video review on the learning curve for laparoscopic radical prostatectomy (LRP). PATIENTS AND METHODS: The initial 40 patients who underwent a transperitoneal LRP (groups 1-4) and the subsequent 20 who underwent LRP by the extraperitoneal approach (group 5) were studied. Eight weeks prior to initiating the LRP program, intensive laparoscopic skills training at a minimally invasive surgery center was undertaken for an average of 4 hours per week. This self-training was continued for 12 weeks into the program, with self-critical review of videotapes of each procedure. The groups were compared with respect to total operative time (ORT), anastomosis time, and blood loss. RESULTS: There were significant differences in the ORT and anastomosis times between each of the first two groups and the last two groups (P <0.001). The learning curve for ORT was overcome after approximately 35 cases, as there were no significant differences in ORT between group 3 and the subsequent groups. The anastomosis took longer to master, as significant time decreases were observed up to group 4, after which, the mean reached a plateau (group 4 v 5 P = NS). The differences in blood loss were not significant. Overall, there were 7 intraoperative (12.7%) and 8 postoperative (14.5%) complications. CONCLUSIONS: The use of similar facilities and training tools can help overcome the steep learning curve of LRP. Longer follow-up is needed to assess these means of attaining better functional results after LRP.

Aged↗

PubMed1999

Factors contributing to laparoscopic failure during the learning curve for laparoscopic Nissen fundoplication in a community hospital.

This study was done to determine the factors contributing to laparoscopic failure (conversion to open surgery or early reoperation) during the learning curve for laparoscopic Nissen fundoplication in a 228-bed nonteaching community hospital. Data were gathered prospectively for the first 100 consecutive patients booked for elective laparoscopic Nissen fundoplication by the four general surgeons at the hospital. All complications were recorded contemporaneously, and particular note was taken of the factors surrounding conversion to open surgery and reoperation within 100 days of surgery. There were no deaths. The conversion rate was 20% and the early reoperation rate 6%. There were two late recurrences. The average operative time was 117 minutes and the average length of stay 1.8 days; 37 operations were performed on outpatients. The laparoscopic failure rate was 26% (18/68) during a surgeon's first 20 operations and 11% (3/28) thereafter (P < 0.09); the corresponding conversion rates were 22% and 4% (P < 0.05). During a surgeon's first 20 operations, the laparoscopic failure rate rose from 21% (12/57) to 55% (6/11) (P < 0.04) if a second surgeon did not assist. After 20 operations, this difference lost its significance. Intrathoracic herniation of the stomach was found preoperatively in 11 (44%) of 25 operations followed by laparoscopic failure and (8%) 6 of 75 without (P < 0.0002). Laparoscopic failure had no correlation with patient age, sex, ASA classification, duration of symptoms, or referring physician's specialty. The individual learning curve for laparoscopic Nissen fundoplication requires about 20 operations to surmount. Factors leading to laparoscopic failure during the learning curve are the surgeon's inexperience, absence of experienced help, and the presence of intrathoracic herniation.

Adult↗

PubMed2005

[Endoscopic vein harvesting. Impact of learning curve on results and rehabilitation].

BACKGROUND: The tendency of modern surgery is towards the reduction of invasiveness. The aim of this study is to evaluate the impact of the learning curve, the reliability, the short term results and the advantages in terms of rapid rehabilitation of endoscopic vein harvesting (EVH) in a consecutive series of 20 patients operated on of aorto-coronary bypass surgery. METHODS: Between February and June 2005, 20 patients between 61 e 82 years of age underwent EVH with the use of Vasoview 5 (Guidant Corporation, Indianapolis, USA). To evaluate the impact of learning curve on the total operative time, patients were divided in 4 chronologically consecutive groups (G1, G2, G3, G4). Intraoperative characteristics and short term results were evaluated. RESULTS: The mean velocity and the mean time of harvesting in G4 were 0,68 cm/min and 45 min. respectively, similar to the time required for a scheletonized left internal mammary artery harvesting. In the first 5 patients 2 conversions were required, one of them related to the EVH technique. No bleeding, functional impairment or infective complications are reported. Active mobilization was possible in every case in the first post-operative day. CONCLUSIONS: EVH is a reliable technique and the learning curve can be limited to the first 5 cases. The foreseeble reduction of infectious complications, the absence of pain and the immediate mobilization of the leg allow a rapid and effective rehabilitation.

Age Factors↗

PubMed2026

Distal versus proximal radial access for diagnostic cerebral angiography: comparative outcomes and learning curve analysis.

BACKGROUND AND PURPOSE: Distal transradial access (dTRA) is an alternative to proximal transradial access (pTRA) for neuroangiography, but comparative real-world data and evidence on its early learning curve remain limited. We compared procedural performance and access-site complications between dTRA and pTRA and evaluated the early learning curve of dTRA. METHODS: We retrospectively analyzed 470 diagnostic cerebral angiography procedures, representing 421 unique patients, performed via radial access at a single center between January 2025 and February 2026, including 237 dTRA and 233 pTRA procedures. Baseline characteristics, including age, sex, body mass index (BMI) category, aortic arch type, and antiplatelet/anticoagulant use, procedural performance, and clinically assessed access-site events were compared between groups. Radial artery occlusion (RAO) was assessed by postoperative bedside pulse examination and confirmed with Doppler ultrasound when clinical findings were uncertain. Multivariable logistic regression was used to evaluate predictors of RAO, persistent bleeding or repeated compression, hand edema, and a composite access-site event endpoint. Because repeated procedures occurred in a subset of patients and event counts were limited, first-procedure sensitivity analysis and analyses of infrequent outcomes were interpreted cautiously. The dTRA learning process was assessed in the first 100 dTRA cases performed by a single operator using multivariable regression, cumulative sum (CUSUM) analysis, segmented trend analysis, and phase-based comparisons. RESULTS: Baseline characteristics were comparable between groups, including age, male sex, BMI category, aortic arch type, and antiplatelet/anticoagulant use. Compared with pTRA, dTRA was associated with more puncture attempts (3.0 [2.0-4.0] vs 2.0 [1.0-3.0], P < 0.001), longer puncture time (2.0 [1.0-5.0] vs 2.0 [1.0-3.0] min, P = 0.003), lower first-pass success (19.4% vs 35.2%, P < 0.001), and a higher crossover rate (11.4% vs 6.0%, P = 0.037). However, dTRA was associated with a lower clinically assessed RAO rate (2.5% vs 7.7%, P = 0.011). On multivariable analysis, pTRA was independently associated with higher odds of RAO (OR 3.27, 95% CI 1.26-8.49, P = 0.015) and the composite access-site event endpoint (OR 3.12, 95% CI 1.55-6.28, P = 0.001). Similar findings were observed in a sensitivity analysis restricted to the first procedure per patient. In the first 100 dTRA cases, cumulative dTRA experience was independently associated with shorter total procedure time (beta = -0.074 min/case, P = 0.009), while CUSUM and moving-average analyses suggested that the major learning effect occurred within approximately the first 10-15 cases. CONCLUSIONS: In this retrospective single-operator cohort, dTRA was associated with lower clinically assessed RAO than pTRA despite greater access difficulty. The early learning effect was mainly reflected in shorter total procedure time. These findings support the feasibility of dTRA but should be interpreted cautiously given the study's observational design and limited anatomical data.

Humans↗

PubMed2006

Permanent prostate brachytherapy: Dosimetric results and analysis of a learning curve with a dynamic dose-feedback technique.

PURPOSE: A permanent prostate brachytherapy (PPB) program utilizing intraoperative inverse-planned dynamic dose-feedback was initiated without prior firsthand experience of alternative techniques. The purpose of this study is to assess the dosimetric learning curve associated with this approach. METHODS AND MATERIALS: A total of 77 patients underwent PPB implants as monotherapy for localized prostate cancer to a prescription dose of 145 Gy with loose 125I seeds between December 2003 and June 2004. Intraoperative and postoperative dosimetric values, total implanted radioactivity, and operating room (OR) times were compared by sequential case number for all cases. RESULTS: The median intraoperative dosimetric values were: D90 (the minimum dose to 90% of the prostate) = 170 Gy (range, 135-203 Gy), V100 (the volume of the prostate that receives 100% of the prescription dose) = 96% (range, 86-100), V150 = 66% (range, 34-86). Median postoperative dosimetric values were as follows: D90 = 168 Gy (range, 132-197 Gy), V100 = 95% (range, 86-99), V150 = 74% (range, 51-84). Median implanted activity was 0.79 mCi per cubic centimeter of prostate (range, 0.541-1.13). There was no significant correlation by case number on any postoperative dosimetric parameter studied. Door-to-door OR time was reduced from median 138 to 97.5 min per case at the end of the series with a correlation coefficient of -0.76 for the initial 28 cases. CONCLUSION: Satisfactory dosimetric parameters can be achieved from the outset without a learning curve effect in an appropriately trained environment. The learning curve for dynamic dose-feedback PPB in a clinic naïve to other techniques is apparent in terms of OR time.

Aged↗

PubMed2002

Learning curves for Gaussian process regression: approximations and bounds.

We consider the problem of calculating learning curves (i.e., average generalization performance) of gaussian processes used for regression. On the basis of a simple expression for the generalization error, in terms of the eigenvalue decomposition of the covariance function, we derive a number of approximation schemes. We identify where these become exact and compare with existing bounds on learning curves; the new approximations, which can be used for any input space dimension, generally get substantially closer to the truth. We also study possible improvements to our approximations. Finally, we use a simple exactly solvable learning scenario to show that there are limits of principle on the quality of approximations and bounds expressible solely in terms of the eigenvalue spectrum of the covariance function.

Journal Article↗

PubMed2004

Laparoscopic adrenalectomy: ascending the learning curve.

BACKGROUND: Soon after its introduction, laparoscopic adrenalectomy (LA) became the procedure of choice in the surgical management of most adrenal tumors. The aim of this study was to assess the outcome and learning curve of the first 100 cases operated by the same surgical team. METHODS: Retrospective analysis of prospectively collected data of 100 consecutive LAs was performed. The parameters studied were indication for surgery, side and length of operation, intra- and postoperative complications, size of tumor, conversion to open surgery, final diagnosis, and length of stay. RESULTS: Between 1996 and 2002, 100 LAs were performed in 90 patients. The procedures included 45 left, 35 right, and 10 bilateral resections for pheochromocytoma (29), Cushings syndrome (27), Conns syndrome (16), nonfunctioning adenoma (13), and others (5). Mean tumor size was 4.16 cm (range, 0.3-11). Overall major morbidity occurred in eight patients (9%); there was one mortality due to cerebrovascular accident in an elderly patient. Five cases (5%) were converted to open surgery. The mean length of stay for the whole group was 4.7 days (range, 2-25). In order to assess the learning curve, procedures were divided into three, equal consecutive groups (n = 33, 33, and 34). Intraoperative complications in the intermediate and late groups were significantly less compared to those in the early group (2/33, 2/34, and 7/33, respectively; (p < 0.05). Similarly, the mean operating time was significantly reduced between the early (169 min) and both intermediate (116 min) and late (127 min) groups (p < 0.005). The conversion rate was reduced between the three groups (3/33, 2/33, and 0/34), but this was not significant (p = 0.06). CONCLUSIONS: As expected, the outcome of LA is associated with a steep learning curve. According to this study, it seems that performance of approximately 30 cases by an experienced laparoscopic surgeon is required to master the procedure.

Adolescent↗

PubMed2006

Routine ileoscopy at colonoscopy: a prospective evaluation of learning curve and skill-keeping line.

BACKGROUND: Ileoscopy is the criterion standard for mucosal lesions of terminal ileum but is performed in 5% of colonoscopy activity, and the need for training is undefined. OBJECTIVE: To assess the learning curve and skill-keeping line of ileoscopy. DESIGN: Prospective randomized study. SETTING: Single GI endoscopy unit. PATIENTS: Adult outpatients referred for colonoscopy. INTERVENTIONS: Patient randomization to ileocolonoscopy by trainees and seniors. MAIN OUTCOME MEASUREMENTS: Ileoscopy skill was divided into the following: ileocecal valve (ICV) intubation (success rate, time) and ileal exploration (length, time). Consecutive blocks of 10 procedures were used to calculate the learning curve and the skill-keeping line. Variables considered to influence ICV intubation were the following: endoscopist experience, ICV morphology, patient age, gender, body mass index, diverticular disease, and preceding abdominal/pelvic surgery. RESULTS: Learning curve showed that competency in ICV intubation (80% success rate) and ileal exploration (16 cm) was achieved after 50 procedures. The skill-keeping line showed that ileoscopy was easy (97% success rate), fast (1 minute), and well accepted up to 45 cm of the ileum. Thin-lipped and volcanic ICV are the most difficult and easiest to intubate, respectively. Crohn's disease and adenomas of the proximal edge of ICV were diagnosed in 2.2%. CONCLUSIONS: Training in ileoscopy is recommended to achieve competency, and endoscopists should consider practicing ICV intubation to maintain and increase their skill. Ileoscopy can be difficult when the ICV is thin lipped or single bulged, and easy when it has a volcanic morphology.

Aged↗

PubMed2007

Histomorphometric assessment of thoracoscopically assisted anterior release in a porcine model: safety and completeness of disc discectomy with surgeon learning curve.

STUDY DESIGN: A retrospective study using histomorphometric analysis to quantify the percentage of discectomy following thoracoscopic anterior release and fusion in a porcine model. OBJECTIVE: To investigate the safety and completeness of disc and endplate removal with respect to the learning curve of the surgeon in a porcine thoracoscopic anterior fusion model. SUMMARY OF BACKGROUND DATA: The thoracoscopic approach has been used to perform an anterior release and fusion before an open posterior instrumentation, however, there is concern that the technique may not provide sufficient visualization or exposure to perform safely and completely. METHODS: A total of 32 pigs (160 discs) were assigned to 2 groups (early experience, n = 16; late experience, n = 16), and underwent 5 level thoracoscopic anterior release followed by anterior instrumentation and fusion from T5 to T10. At 4 months after surgery, the spines were harvested, and each discectomy disc was histomorphometrically analyzed to determine the percentage of disc excision and amount of endplate removal. RESULTS: There were no significant differences in the percent disc excision between the early (67% +/- 11%) and late groups (69% +/- 10%). Greater than 50% of the disc was excised in 151 of 160 discectomies (94%). Both superior and inferior endplates were resected in 92 of 160 disc levels (57%). The amount of endplate removal had improved over time in both early and late groups (P < 0.0001). The histologic examination revealed no evidence for posterior longitudinal ligament disruption or spinal canal encroachment in any disc. CONCLUSIONS: Video-assisted thoracoscopic discectomy is safe and allows for a significant amount of disc material excision. This study did not demonstrate a learning curve with respect to the amount of disc material excised, but a learning curve was seen for endplate excision.

Animals↗

PubMed2001

Learning curve of the Inoue technique of percutaneous mitral balloon valvuloplasty.

There is controversy as to whether the double-balloon or the Inoue technique of percutaneous mitral balloon valvuloplasty (PMBV) provides superior immediate and long-term results. This study was undertaken to analyze the effect of the learning curve of the Inoue technique of PMBV in the immediate and long-term outcome of PMBV. The learning curve of Inoue PMBV was analyzed in 233 Inoue PMBVs divided into 2 groups: "early experience" (n = 100) and "late experience" (n = 133). The results of the overall Inoue technique were compared with those of 659 PMBVs performed with the double-balloon technique. Baseline clinical and morphologic characteristics between early and late experience Inoue groups were similar. Post-PMBV mitral valve area (1.89 +/- 0.56 vs 1.69 +/- 0.57 cm(2); p = 0.008) and success rate (60% vs 75.9%; p = 0.009) were significantly higher in the late experience Inoue group. Furthermore, there was a trend for less incidence of severe post-PMBV mitral regurgitation > or = 3+ in the late experience group (6.8% vs 12%; p = 0.16). Although the post-PMBV mitral valve area was larger with the double-balloon technique (1.94 +/- 0.72 vs 1.81 +/- 0.58 cm(2); p = 0.01), the success rate (71.3% vs 69.1%; p = NS), incidence of > or = 3+ mitral regurgitation (9% vs 9%), in-hospital complications, and long-term and event-free survival were similar with both techniques. In conclusion, there is a significant learning curve of the Inoue technique of PMBV. Both the Inoue and the double-balloon techniques are equally effective techniques of PMBV because they resulted in similar immediate success, in-hospital adverse events, and long-term and event-free survival.

Boston↗

PubMed2005

Carotid artery stenting with neuroprotection: assessing the learning curve and treatment outcome.

PURPOSE: Carotid artery stenting (CAS) has emerged as an acceptable treatment alternative in high-risk patients with carotid stenosis. The purpose of this study was to assess the effect of the learning curve on treatment complications and the clinical outcomes of CAS. METHODS: Clinical variables and treatment outcomes of 200 consecutive CAS procedures in 182 patients (mean age 72 years) with carotid stenosis > or = 70% during a 40-month period were analyzed. Four sequential groups (groups I, II, III, and IV) of 50 consecutive interventions were compared with regard to technical success, periprocedural complications, and treatment outcomes. RESULTS: Treatment indications and relevant risk factors were similar among the 4 groups. The overall technical success and combined 30-day stroke and death rates were 98% and 2.5%, respectively. An increase in the technical success rate was noted in the latter 3 groups compared with group I (P < .05). Total procedural time and contrast volume were significantly higher in group I compared with the latter 3 groups (P < .05). The intraoperative anticoagulation regimen was changed from intravenous heparin combination to bivalirudin after the first 54 patients, which resulted in decreased bleeding complications in groups III and IV (P = 0.03) compared with the first group. The 30-day stroke and death rate in groups I and II were 8% and 2%, respectively, and was decreased significantly in groups III and IV (0% and 0%, respectively, P < .05). A Cox regression model identified procedural volume (P = .03) as a predictor of decreased complication rate. CONCLUSIONS: CAS with neuroprotection can provide excellent treatment outcomes. Our experience demonstrates a procedure-associated learning curve as evidenced by decreased procedure-related complications, fluoroscopic time, and contrast volume occurring with increased physician experience. Procedural success was also enhanced partly by endovascular device refinement and an improved anticoagulation regimen. Successful CAS outcomes can be achieved once physicians overcome the initial procedure-related learning curve.

Aged↗