Page 58 - World Journal of Laparoscopic Surgery

World Journal of Laparoscopic Surgery, January-April 2008;1(1):56-59
Rehana Jabeen Raja
The Impact of the Learning Curve in

Laparoscopic Surgery

Rehana Jabeen Raja
25, Acacia Drive, Runda, Nairobi, Kenya

Abstract: TP Wright originally introduced the concept of a learning point defines where the performance of an individual surgeon
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curve in aircraft manufacturing in 1936. He described a basic theory begins. Secondly, the rate of learning measures how quickly
for costing the repetitive production of airplane assemblies. The term the surgeon will reach a certain level of performance and thirdly
was introduced to medicine in the 1980s after the advent of minimal the asymptote or expert level measures where the surgeons
access surgery. It also caught the attention of the public and the legal performance stabilizes. This has implications for the
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profession when a surgeon told a public enquiry in Britain that a high laparoscopic surgeon—it suggests that practice always help
death rate was inevitable while surgeons were on a learning curve. 2
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Recently it has been labeled as a dangerous curve with a morbidity, improve performance but the most dramatic improvement
mortality and unproven outcomes. Yet there is no standardization of happens first. Also with sufficient practice surgeons can achieve
what the term means. In an endeavor to help laparoscopic surgeons comparable levels of performance.
towards evidence based practices this commentary will define and
describe the learning curve, its drawing followed by a discussion of the THE DRAWING OF LEARNING CURVES
factors affecting it, statistical evaluation, effect on randomized controlled There are a variety of methods of constructing learning curves.
trials and clinical implications for both practice and training, the They all assume that successive exposures in a learning series
limitations and pitfalls, ethical dilemmas and some thoughts to pave may be plotted on the x-axis, response characteristics on y-axis
the way ahead.
and the data points distributed in the xy plane may be legitimately
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connected by a curve. This is the Cartesian Method. More
DEFINITION AND DESCRIPTION
recently the Cumulative Sum Method has been applied for the
For the Wright learning curve, the underlying hypothesis is construction of these curves for basic skills in anesthetic
that the direct man-hours necessary to complete a unit of procedures—the method consists of relatively simple
production will decrease by a constant percentage each time calculations that can be easily performed on an electronic
the production quantity is doubled. In manufacturing, the spreadsheet. Statistical inferences can be made from observed
learning curve applies to the time and cost of production. Can a successes and failures. The method also provides both
surgeons learning curve be described on similar lines? A simple numerical and graphical representation of the learning process. 7
definition would be : the time taken and/or the number of The multimode learning curve is useful because several
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procedures an average surgeon needs to be able to perform a factors can be put into one graph. The earlier used method of
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procedure independently with a reasonable outcome. But then the performance analysis with its on the spot appraisals at
who is an average surgeon ? Another definition may be that a certain time intervals has been replaced by continuous
learning curve is a graphic representation of the relationship assessment. For continuous data like operation time the Moving
between experience with a new procedure or technique and an average method is useful. 9
outcome variable such as operation time, complication rate,
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hospital stay or mortality. A learning curve may also be FACTORS AFFECTING LEARNING CURVES
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operationally defined as an improvement in performance over A complex hierarchy of factors are involved here. At the bottom
time. Although learning theorists often disagree about what factors like guidelines, protocols and standards for clinical
learning is, they agree that whatever the process is, its effects governance agreed upon by the medical fraternity are vital.
are clearly cumulative and may therefore be plotted as a curve. Next the Institutional policies and cost effectiveness are
By cumulative it is meant that somehow the effects of experience contributory. Needless to say the surgical team, the case mix
carry over to aid later performance. This property is fundamental and public awareness are relevant. The final level in the hierarchy
to the construction of learning curves. The improvement tends that can influence individual learning is the characteristics of
to be most rapid at first and then tails off. Hence there are three the surgeon such as attitude, capacity for acquiring new skills
main features of a learning curve. First, the initial or starting and previous experience. 10

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