Comparison of Linear Staplers during Laparoscopic Roux-en-Y Gastric Bypass
Prospective Randomized Comparison of Linear Staplers during Laparoscopic Roux-en-Y Gastric Bypass
J. K. Champion MD, Mike Williams MD
Videoscopic Institute of Atlanta
Background: The development of laparoscopic linear staplers enabled minimally invasive approaches to bariatric surgery, but there have been no comparison studies of the two current six row devices. This paper reports our experience with a prospective randomized comparison of six row linear staplers during laparoscopic Roux-en-y gastric bypass (LRYGB).
Methods: From January-March 2003, 100 patients were randomly assigned to undergo LRYGB with either a Endo-GIA Universal six row stapler (USSC, Norwalk, Conn.) or the ETS-Flex six row stapler (Ethicon Endo-Surgery Inc., Cincinnati, Oh.). Mean pre-op weight / BMI were 138 ± 24 kg / 49 ± 8 for 50 Endo-GIA patients, and 135 ± 42 kg / 49 ± 7 for 50 ETS-Flex patients. Parameters measured included quantity of cartridges, handles, hemoclips, estimated blood loss, misfires, OR time, post-op leaks and bleeds, and cost.
Results: Mean follow-up was 135 days (range 90-180). The ETS-Flex group experienced significantly more misfires (28% vs. 2%, p<.001), hemoclips applied (30±9 vs. 21±7, p<.001), estimated blood loss (132±56 vs. 100±32, p<.001) and OR time (66±19 vs. 58±13, p<.02) compared to the Endo GIA group respectively. There was one post-op leak associated with the ETS-Flex group, and two post-op bleeds with the Endo-GIA group, which was not a significant difference. The Endo-GIA group averaged $319 more per case for staple cost.
Conclusion: This study demonstrated while the ETS-Flex stapler was less expensive, it was associated with significantly more technical failures requiring surgeon intervention to reduce potential patient morbidity compared to the Endo-GIA.
Keywords: Staplers, Laparoscopic, Gastric bypass
Advanced laparoscopic gastrointestinal procedures such as the Roux-en-Y gastric bypass were made possible with the introduction of linear endoscopic staplers in the early 1990’s . Multiple refinements have been made in the last decade, and the current “state of the art” technology allows for cartridges with six rows of staples which vary in staple height to accommodate various tissue thicknesses. The instrument handle will pass through a 12 mm trocar and articulate to allow proper alignment despite fixed port placement sites. In addition, the recent introduction of extra long handles to accommodate morbidly obese patients has expanded the limits of laparoscopic bariatric surgery [2,3,4].
This technology has come with a price however, and the cost of disposable staplers is a major expense with laparoscopic gastric bypass. Managed care financial constraints and cost containment policies have necessitated institutions to negotiate exclusive supply contracts with industry for stapling devices to limit expense. The choice of stapling device is usually made by the materials manager or hospital administrator and based solely on cost, with the assumption that all commercially available staplers perform equally well. The lack of controlled trials which investigate morbidity related to stapling products has hampered the ability to make informed choices relying on evidence based medicine, which should be the standard today.
While mechanical staplers ease the task of transecting and re-anastomosing tissue, they are associated with a definitive failure rate [5,6,7]. Staple line failures and anastomotic leaks are a principal etiology of patient morbidity and death after gastric bypass surgery [8,9,10]. It therefore behooves us to investigate and define the shortcomings of stapling products we employ in our surgical practice.
This study is the first prospective randomized trial of current commercially available six row endoscopic linear staplers and compares the Endo GIA Universal stapler (USSC, Norwalk Conn.) versus the ETS-Flex stapler (Ethicon Endo-Surgery Inc., Cincinnati OH) during laparoscopic Roux-en-y gastric bypass (LRYGB).
This was an independent study with no industry funding.
Materials and methods:
From January to March 2003, 100 consecutive patients were prospectively randomized to undergo a primary LRYGB utilizing the linear endostapler technique with either the Endo-GIA or ETS-Flex six row staplers with an extra long handle. The procedure was performed by a single surgeon (JKC) who had extensive experience with both products, to eliminate surgeon variability. Patient selection criteria followed National Institutes of Health guidelines for surgical management of morbid obesity . Pre-operative characteristics recorded for the groups included age, gender, weight, body mass index (BMI), co-morbidities, and previous open abdominal procedures and are summarized in table one.
Outcomes data were collected prospectively and maintained in a Microsoft Access database. Patients were seen in our office for follow up at 3 weeks, 3 months and at 6 months. Parameters measured included the quantity of cartridges and handles utilized, hemoclips applied to staple lines, stapler misfires, operative time, estimated blood loss, post-operative leaks, post-operative bleeding and stapler costs. Stapler misfires were classified as major if it required surgeon intervention to prevent patient morbidity, and minor if it impeded the operation, but didn’t result in potential patient injury. Operating time was measured from the skin incision to completion of the intra-operative endoscopy just prior to removing the trocars. Post-operative bleeding was defined as a decrease in hematocrit of ten points, or any transfusion.
Patients were admitted on the morning of surgery and received subcutaneous enoxaprin, sequential compression devices, and I.V. prophylactic antibiotics on arrival to the floor. We used a six-port technique to complete our LRYGB. The abdomen is entered without insufflation utilizing a direct view 12mm trocar. Insufflation is begun at 15mm Hg and careful inspection made to rule out any trocar injury. The remaining four 5mm trocars and one 12mm trocar are inserted under direct visualization. The operating table is positioned in extreme reverse trendelenburg position and a 5mm Allis clamp is inserted via an epigastric trocar and positioned under the liver and attached to the diaphragm to provide exposure. The peritoneal attachments are taken down along the left crus to expose the angle of His. An endoscopic ruler is then used to measure 5cm from the angle of His along the lesser curve to construct the vertically oriented pouch. A window is created along the lesser curve into the lesser sac at the 5cm mark by blunt dissection in order to position the stapler for the pouch construction. A 45 mm linear surgical stapler (Endo GIA II Universal, US Surgical, Norwalk, Conn.) or (ETS-Flex, Ethicon Endo-Surgery Inc. Cincinnati, OH. USA) with a 3.5mm staple is then positioned and fired horizontally on the lesser curve to begin pouch formation. A 50 Fr blunt tip bougie is passed along the lesser curve and placed gently against the staple line. The stapler is repositioned vertically alongside the bougie and fired vertically up through the angle of His to complete the transection of the pouch. The staple lines are inspected for bleeding and uniform formation. Bleeding points are controlled with the application of hemoclips and malformed staple lines are over sewn. The patient is re-positioned supine and the greater omentum is retracted superiorly and the ligament of Trietz identified. The bowel is measured 40 cm distal to the ligament with an endoscopic ruler and transected with an Endo GIA II Universal (USSC) linear endoscopic 60mm cartridge with 2.5 mm staples or the ETS-Flex (Ethicon) using the 45mm cartridge with 2.5mm staples since 60mm length cartridges were not available for the Ethicon stapler during this study. The mesentery is lengthened with one or two firings of a 45 mm linear stapler with 2.0 mm staples (Endo GIA II, US Surgical, Norwalk, Conn.) or 2.5mm staples (ETS-Flex, Ethicon Endo-Surgery Inc., Cincinnati, OH.) because of the lack of available 2.0 mm staples for Ethicon’s stapler. A measurement is then made an additional 60 cm if the BMI is 40, 80cm if the BMI is 50 and 110 cm if the BMI is 60 as a general guide. The distal jejunum is sutured to the proximal jejunum with two stay sutures of permanent suture placed via an extracorporeal technique. An enterotomy is made on the ante-mesenteric border of the bowel between the two sutures, and a linear 45 cm stapler with 2.5 mm staples is inserted and fired to create a side-to-side entero-enterostomy. The enterotomy opening is closed with a hand sewn 2-0 silk running suture. A window is made in the greater omentum just anterior to the transverse colon and the end on the roux limb is passed ante-colic and ante-gastric. If the greater omentum is especially thin, the roux limb can be passed anterior without a window.
After the roux limb is passed to the upper abdomen the patient is re-positioned in extreme reverse trendelenburg and the gastro-jejunostomy is performed. The side of the roux limb is sutured to the anterior edge of the gastric pouch with two extracorporeal permanent sutures. An enterotomy is made in the bowel and pouch with mono-polar cautery. A linear stapler with a 45mm cartridge (Ethicon group) with a 3.5 mm staples was inserted one-third way and fired or a 30mm length linear stapler with 3.5mm staples (USSC group) was inserted halfway and fired to create the anastomosis. A 30 Fr blunt tipped bougie is carefully passed by anesthesia across the anastomosis and the enterotomy is closed around the bougie with a running 2-0 silk suture. Patients undergo routine intra-operative gastroscopy to rule out technical errors. Incisions are closed with 3-0 plain gut subcuticular, with no fascial closure at any site.
Data are expressed as mean ± standard deviation unless otherwise stated. Statistical significance was determined by Fisher’s exact test or Chi-Square contingency test and was assumed for a p value of less than 0.05.
Mean follow-up was 135 days (range 90- 180)
There was no statistically significant difference in age, gender, BMI, weight, co-morbidities, or previous open abdominal surgery between groups.
Intra-operative outcomes for the two cohorts is listed in Table 2. The ETS-Flex group experienced significantly more stapler misfires, hemoclips applied for staple line bleeding, estimated blood loss, and OR time compared to the Endo-GIA group. Etiologies of stapler misfires are listed in Table 3. The one minor Endo-GIA misfire was due to a 45 mm 3.5 mm cartridge which wouldn’t load onto the handle and required replacement. The seven minor ETS-Flex misfires were due to five occurrences in which two hands were required to force open the stapler after firing and locking on tissue, one visible malformed staple line which didn’t require repair, and one case where poor stapler angulation would not allow a proper pouch construction and was abandoned for a Endo-GIA. The seven major misfires were secondary to four malformed staple lines which required suture repair, one cartridge firing halfway on the small bowel and freezing on the tissue which required a forceful internal laparoscopic dislodgement, and two total misfires in which the cartridge popped out of the handle during firing and divided tissue without firing a staple line. In the incident of the two total misfires, one occurred on the small bowel mesentery and required re-stapling both side of the laceration, and one occurred in formation of the gastro-jejunostomy and required the anastomosis be constructed by a totally hand sewn technique.
The number of cartridges and handles utilized and cost data are listed in Table 4. The difference in number of cartridges fired was not significant, but the ETS-Flex cohort required significantly more handles (p < .001). Despite the difference in utilization volume, the ETS-Flex group was less expensive than the Endo-GIA group by $318.99 per case.
There were two patients in the Endo-GIA group with post-op bleeding indicated by a decrease in hematocrit of more than ten points, and none in the ETS-Flex group which was not significant.
One post-op leak occurred in the ETS-Flex group and none in the Endo-GIA cohort which was also not significant.
There was no long term morbidity.
There are currently two commercially available six row endoscopic staplers which can be utilized for laparoscopic bariatric surgery in the United States, and there are several design differences in the products which may influence function and performance. The Endo-GIA stapler comes as a single handle which can be fired 25 times and will accommodate one of three cartridge lengths of 30mm, 45mm, and 60mm, in four staple heights of 4.8mm, 3.5mm, 2.5mm and 2.0mm. Each Endo-GIA cartridge comes with a fresh knife blade to fire the staples and divide the tissue, and the width of the opposing jaws is controlled with a “cog” which advances along the length of the cartridge. The ETS-Flex stapler handle has a reusable blade incorporated into the shaft and is recommended to be fired only eight times before replacement. The cartridges are all 45mm long and come in staple heights of 3.5mm and 2.5mm. The inclusion of the reusable blade in the handle shaft is the etiology of many of the misfires and functional problems we experienced with the ETS-Flex product in our opinion, and would be easily correctable by the manufacturer. We observed the reusable blade began to tear tissue rather than cut as it became dull by the fifth firing, and was the source of the poor staple lines requiring repair and the excessive bleeding compared to the Endo-GIA. This prompted a change in our technique midway through the study with the ETS-Flex, for if we saw we were going to require more than 8 firings to complete a case and would need a second handle anyway, we would only fire the first handle five times and use a fresh handle and blade to divide the small bowel mesentery. Despite this lapse in our protocol which could have favored the ETS-Flex stapler, the ETS-Flex still exhibited significantly more estimated blood loss and hemoclips applied.
The presence of the blade within the shaft also necessitates moving the articulation joint approximately 5 cm proximal to the cartridge which severely limits articulation and requires more shaft be inserted intra-abdominally before the instrument can be flexed compared to the Endo-GIA. This resulted in our having to abandon the ETS-Flex in one case to construct a small pouch along side a bougie with an acute angulation.
We would suggest elimination of the re-usable blade in the ETS-Flex product, but pending that development, we recommend consideration of always opening two handles to reduce the number of firings per handle and to speed the loading process which is more cumbersome with the ETS-Flex handle. The increase in OR time with the ETS-Flex was due to a combination of time required to repair the large number of major misfires and the cumbersome loading process compared to the Endo-GIA.
The cost differential would be less between the two products if two handles were utilized for each ETS-Flex case, but relying on only the initial fixed cost can be misleading if you consider the cost of leaks secondary to a product. The leak associated with the ETS-Flex required 18 additional hospital days at a cost of $44,342.50, which averages out to $886.85 per case for this 50 case series, and would result in the ETS-Flex averaging $567.86 more per case.
The numbers of cartridges utilized was nearly identical (Table 4) despite the three lengths available for the Endo-GIA versus the single 45 mm for the ETS-Flex, which raises a question whether cartridge variability is an important feature for laparoscopic staplers. The 60 mm length has always posed a mechanical problem in obtaining staple approximation at the tip of the load, as the force required to achieve closure rises exponentially with the length of the cartridge.
Prior to initiating the study we performed a series of laparoscopic gastric bypass procedures to re-familiarize our surgical crew with the ETS-Flex product to reduce human error as much as possible. We did experience a stapler load dislodgement during this process (not included in the study) and the issue was raised of a nursing error, therefore during the study each ETS-Flex load was visualized prior to firing to ensure proper technique. Despite this precaution we experienced two major dislodgements with a significant potential injury requiring the surgeon to intervene.
All major stapler misfires during this study were identified and repaired resulting in no late morbidity which was a weakness of the study to evaluate true outcomes. To achieve a true comparison a survival animal study would need to be performed with the stapler misfires and malformed staple lines not repaired and evaluate resultant morbidity. Omitting the repair of an obvious staple line misfire would be un-ethical on the part of any investigator. The one staple line misfire classified as minor and not repaired was the result of the inner third row of staples not forming, but the two additional outer rows did form and appeared intact.
In conclusion, the ETS-Flex stapler was less expensive, but was associated with significantly more technical failures compared to the Endo-GIA.
Dr Champion currently serves on the speaker’s bureau for Ethicon Endosurgery and USSC.
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Pre-operative group characteristics
|Age||43 ± 10||44 ± 10|
|BMI||49 ± 8||49 ± 7|
|Weight||135 ± 42 kg||138 ± 24 kg|
|Co-morbidities||4.7 ± 1.7||4.7 ± 1.9|
|Previous surgery||0.44 ± 0.5||0.62 ± 0.5|
|EBL||99 ± 32||132 ± 56||p < .001|
|Hemoclips applied||21 ± 7||30 ± 9||p < .001|
|OR time||58 ± 13||66 ± 19||p < .02|
|Misfires||1 (2%)||14 (28%)||p < .001|
EBL = estimated blood loss
Etiologies of stapler misfires
|Classification of misfires||ETS-Flex||Endo-GIA|
5- required two hands to open
1- poor angulation
1- poor staple line, not sutured
45mm cartridge wouldn’t load on handle
1- 45mm load fired halfway and froze on tissue
2- total misfires, load dislodged and cut but didn’t staple tissue
4- malformed staple lines requiring suture repair
Number of cartridges, handles and costs
|Total # cartridges||442||448|
|Total # handles||50||81|
|Total Cost||$77,215.78 US||$61,266.22|