2005 SAGES Abstracts

POSTER ABSTRACTS
SAGES 2005
ent screws, to adjust the friction of the ball, giving the angle of
the instrument and a second screw for defining the length of
optical instruments inside the abdomen. The ball has to be in
close contact with the abdominal wall. The ball is held by a
metal clamp, which is attached to a mechanical retractor,
which connects the system with the operating table.
After adjusting the friction to the needs of the operation and
allowing a change of the position by using one hand without
opening the screws the optic is focused upon the operative
field. The operation is performed with the use of a curved
grasper for the left hand, which allows that both instruments
for the surgeons are located on the right side of the optic, e.g.
in gallbladder surgery. Therefore, there is no conflict between
operative instruments and retractors given. If the position of
the optic or the retracting instrument has to be changed, it can
be performed with the move of one hand in a very short time
(no more than a second).
Results: We have operated with the use of solo-surgery 50
patients with chronic cholecystitis and gallbladder-stones and
5 patients with acute cholecystitis. It takes 0.9 minutes to
establish the retracting technology, to break down the system
0.5 minutes in the average.
All procedures went smooth without any complications. We
observed that less movements of the camera have been performed
compared to the assisted procedure and that the position
of the optic was clearly more stabile than the assisted procedure.
We perform today routinely solo-surgery for resection
of the gallbladder in chronic cholecystolithiasis, except in educational
tasks. One ball trocar is routinely used for retraction of
the liver in fundoplication, so that a third assistant is never
necessary.
P238–Ergonomics/Instrumentation
OBJECTIVE ASSESSMENT OF KNOT QUALITY SCORE, Daniel
L Howell MD, Huang Ih-Ping MD,E A Goldenberg MD,C D
Smith MD, Endosurgery Unit, Department of Surgery, Emory
University
Surgical skills in laparoscopy are difficult to acquire and
assess. Knot Quality Scores (KQS) have been used by some to
assess the quality of laparoscopically tied knots as a measure
of the difficult task of laparoscopic suturing and knot tying.
KQS is calculated by the following formula,
We have found that KQS has a large amount of variability for
knots that slip. This study compared tensile strength of tied
suture to that of untied suture utilizing a measure of elasticity
known as Young’s modulus (YM). 100 four throw, slip
square knots were tied laparoscopically in a box trainer using
USS 2-0 silk suture. Knot quality was assessed using an In-
Spec 2200 Benchtop tensiometer and the KQS was calculated
using the previously described formula. Mean breaking force
was determined for tied and untied suture along with the distraction
of the suture in mm. Knots with a plateau of the curve
extending beyond 6.5mm were designated as slipped. From
the maximum breaking strain and distance of distraction in
mm the YM was calculated in Pascals.Mean breaking force
was 20.04 for slipped knots and 20.66 in knots that did not slip.
The mean distraction in slipped knots was 7.8 mm with a KQS
of 0.31 compared to 5.73mm and KQS of 0.34 in knots, which
did not slip p < 0.05. Mean YM in untied suture was 3.40x10-
3 Pascals in slipped knots the YM was 2.39x10-3 Pascals and
3.30x10-3 Pascals in knots that did not slip p< 0.05. While
KQS provides a benchmark for knot quality knots which slip
may result in a falsely high KQS. Calculating YM for the knotted
ligature reveals that in tight knots force is distributed as
the suture elongates due to its elastic properties. When knots
slip the measure of elasticity is much lower implying most of
the force is distributed as the knot tightens despite similar
KQS between the two populations. This will be important as
skills assessment strategies are implemented in General
Surgery Residencies and in the Credentialing of surgeons.
188 http://www.sages.org/
P239–Ergonomics/Instrumentation
DEVELOPMENT OF A NEW FLAT NEEDLE AND TIGHTER
THREAD FOR ENDOSCOPIC SUTURING, Soji Ozawa MD,
Yasuhide Morikawa MD,Toshiharu Furukawa MD,Junya
Oguma MD,Hironori Asada MD,Masaki Kitajima MD,
Department of Surgery and Department of Obstetrics &
Gynecology, School of Medicine, Keio University, Tokyo, Japan
As a means of facilitating intracorporeal suturing, we made 1/3
of the body of a curved needle flat to allow it to be grasped
easily, and we reduced the surface coating of the thread as
much as possible to prevent the knots from loosening. The
new needle and the thread were evaluated in this study.
Ten surgeons manipulated a needle
driver and an assistant grasper to grasp the new flat needle
(70% oblateness, F needle; 25 mm, 1/2 circ., AZWELL, Japan)
and a regular round needle (R needle) ten times each with a
Lap Coacher training system (Hakko, Japan). The time
between needle insertion and grasping as correctly as possible
was measured. The tip of the needle driver and the needle
were photographed from two directions, and the error in angle
between 90 degrees and the actually measured angle was analyzed.
A multiple overhand knot was made on the sponge with
99.75% reduced silicone-coated thread (Reduced thread; 3-0,
polyester, braided, AZWELL) and regular silicone-coated
thread (Regular thread). The minimum number of multiple of
overhand knot required to hold the knot when the surgeon’s
hand was removed was counted. The time in the F-
needle group (12.6 +/- 4.3 sec) was shorter than in the R-needle
group (18.1 +/- 9.2 sec) (p < 0.01). The error in pitch angle
was 7.4 +/- 7.3 degrees in the F-needle group and 9.3 +/- 8.1
degrees in the R-needle group (p = 0.08), and the error in yaw
angle in the F-needle group (4.7 +/- 5.1) was smaller than in
the R-needle group (10.2 +/- 8.9 degrees) (p < 0.01). The product
of time and the number of degrees of error in the pitch
angle and the yaw angle with the F needle were significantly
smaller than with the R needle in 20% and 60% of the surgeons,
respectively. The product of time and the sum of the
error in the pitch and yaw angles with the F needle was significantly
smaller than with the R needle in 30% of the surgeons.
The minimum number of multiple of overhand knot made with
dry Reduced thread and dry Regular thread were 3 and 5,
respectively, versus 2 and 5, respectively, with wet Reduced
thread and wet Regular thread. The results
demonstrated that the new flat needle is grasped more correctly
and quickly than conventional round needles, and that
the thread with reduced surface coating is less likely to loosen.
It was, therefore, concluded that the combination of the new
flat needle and thread with reduced surface coating is useful
for endoscopic suturing.
P240–Ergonomics/Instrumentation
FAILURE MODE AND EFFECTS ANALYSIS ON THE LAPARO-
SCOPIC CHOLECYSTECTOMY, Kazuhiko Shinohara MD, School
of Bionics,Tokyo Univesity of Technology
Failure Mode and Effects Analysis (FMEA) on the procedure of
laparoscopic cholecystectomy was performed for the purpose
of medical safety. The procedure of laparoscopic cholecystectomy
was classified into 12 steps by the method of Indutrial
Enginnering. Incidents and troubles were analysed in each
step and their influences were classified into 4 classes in the
manner of FMEA (1:catastrophic,2:critical,3:marginal,4:negligible).
49 cases of the incidents and troubles were extracted and
all of them were classified in 1 or 2. 76% of the incidents and
troubles were caused by the factors of medical electric devices
and surgical instruments. 55% were caused by both human
and machine factors ,25% were caused by human factors. 43%
of the incidents and troubles were peculiar to the laparoscopic
surgery. One of the safety problems cleared from this study
was that most of the incidents and troubles could be detected
only by the human and the lack of the integrated monitoring
system for the total operational environments.
P241–Ergonomics/Instrumentation
ASSESSING ENDOSCOPIC CUTTING PERFORMANCE WITH
AND WITHOUT THE TARGET BEING HELD WITH THE NON-
PREFERRED HAND, Bin Zheng PhD, Stephen Obradovich,Alan