81OSATS was created with open surgical skills in mind but served as a platform for
later MIS-specific objective measures.
GOALS
For the most part, OSATS has held up well for evaluating technical skills in open
procedures but needed adaption for minimally invasive procedures. There are any
number of global rating scales for MIS but few that could be used universally for the
huge variety of surgical skills and presentations seen in MIS. Take, for example,
ORCS, the objective component rating scale for a Nissen fundoplication. It is a vali-
dated and reliable tool, but only for one particular surgery, and only during opera-
tive procedures [ 36 ].
The result was Global Operative Assessment of Laparoscopic Skills (GOALS)
[ 37 ]. While similar to OSATS with different metrics graded on Likert scale from 1
to 5, GOALS clearly tests different factors, confirmed in Table 5.2. Depth percep-
tion is certainly an aspect in open procedures but is compounded and vastly more
complicated when viewing an image generated by a monocular endoscope. OSTATS
tested time and motion, and in GOALS this is more clearly outlined under the “effi-
ciency” metric while blended with the original “flow of operation.” Bimanual dex-
terity is critical to MIS – and as such has earned its own metric. OSATS’s “respect
for tissue” translates to “tissue handling” but is asking the same question. Similarly,
“knowledge of specific procedure” becomes the similar “autonomy” grade, which
inquires how well the procedure was performed without outside aid [ 37 ].
To test GOALS, researchers compared the prospective global scale against a
procedure-specific ten-item checklist and two 10 cm visual analogue scales (VAS).
The VAS asked raters to place a mark on the line for the degree of difficulty, ranging
from “extremely easy” to “extremely difficult” and overall competence extending
from “maximum guidance” to “fully competent” [ 37 ]. The checklist could not dif-
ferentiate skill level, was only applicable to a laparoscopic cholecystectomy, and
had poor interrater reliability. The VAS similarly failed between proctors but did
have construct validity. Overall, there was no added benefit to adding in the check-
list or VAS, as such they were excluded from the final version of GEARS. Vassilou
suggested that the VASs were too lenient, and the checklists too rigid, but that the
global ratings scale fell somewhere in the middle [ 37 ].
The transition from OSATS to GOALS has proven to be a consistent one. Dual
analysis of novice laparoscopic surgeons reveals high correlation between OSATS
and GOALS scores [ 38 ].
GOALS have achieved evidence for construct validity several times over. Gumbs
et al. showed that novice and experienced residents can accurately be differentiated
from each other using GOALS during laparoscopic cholecystectomy and laparoscopic
appendectomy procedures [ 39 ]. Experienced surgeons (PGY 5–6) consistently outper-
formed novice surgeons (PGY 1–3) with statistical significance during laparoscopic
cholecystectomy and laparoscopic appendectomy procedures [ 39 ]. On a finer scale,
GOALS could distinguish even between novice and graduating surgical fellows [ 40 ].
In the Gumbs study, attending surgeons completed GOALS as part of each case’s
operative note, with the scale automatically generated. This method not only
5 Performance Assessment in Minimally Invasive Surgery