At Lexington Medical, Inc., we don’t strive for “A’s”.
We want “B’s”.
Introduction
An endoscopic linear cutter, or a surgical stapler, has a deceptively simple job: deploy four or six rows of staples and divide the tissue between them. In practice, proper staple formation is far more technically demanding, and less reliable than most of us appreciate.
Surgical staplers can be evaluated on many dimensions—ease of firing, reload variety, hemostasis, and aerostasis—but the most important metric is the quality of the “B” formed by each individual staple.
A surgical staple begins as a “U” shape; upon firing it should close into a symmetric “B,” trapping tissue and achieving a secure seal, while allowing blood flow. Although the shaping mechanism is analogous to a paper stapler, the paper staple is generally flatter without plump “B” loops, because blood flow is obviously not a consideration.
Example of B-shaped staples formed by the AEON reload cartridge
A typical endoscopic surgical stapler reload contains 45–90 individual staples. Most surgeons—reasonably—assume the majority form properly after firing.
The evidence tells a different story, and that gap between assumption and reality has real clinical consequences. The widespread use of three staple rows either side of the cut line is likely no accident; redundancy compensates for the fact that no single staple can be relied upon to perform perfectly.
Staple line failure can result from excessive tissue thickness and density, calcification, use of an incorrectly sized reload, and stapler design. Not all tissue is the same—some tissue such as bowel is a relatively easy task for a stapler to perform well in. Tissue such as pancreas, liver, emphysematous lung, sensitive vasculature and thick stomach can push the performance of a stapler to its limits, and it is in these tissues where many staplers have marginal or poor performance. Innovations in stapler engineering and design by Lexington Medical have overcome many of these obstacles that continue to challenge legacy devices. We measure ourselves in the most challenging conditions.
What is a Properly Formed Staple?
We all know what a “B” looks like, but there are varying definitions for what a properly formed staple is.
In a 2014 paper sponsored and authored by Ethicon [1], a chart was published which categorized various staple shapes as acceptable or unacceptable (Figure 1). Many authors would now agree that some of the staples considered acceptable in those images are far from ideal [2].
Another Ethicon sponsored study defined optimal staple formation as “B”, “R”, or “D” shaped staples [3] (Figure 2).
Our years of expertise, focus, and data show that staples should ideally form into symmetrical B’s for optimal clinical performance (Figure 3), and this is in alignment with other authors [2] (Figure 4).
Figure 1
Figure 2
Properly Formed B-Staple
Figure 3
Figure 4
What Does the Evidence Show?
Key takeaway: Across multiple independent and manufacturer-sponsored studies, the majority of staples fired by legacy brand, contemporary endoscopic linear cutters fail to achieve optimal “B” formation in both clinical scenarios and controlled laboratory conditions.
Precompression Time and Staple Formation (Nakayama et al., 2011)
The first scientific evaluation of staple formation was published in 1995 from Hong Kong [4], which identified poorly formed staples in 58% of pulmonary wedge resection specimens examined radiographically, but they did not quantify the percentage of staples that were properly formed.
A subsequent 2011 study from Japan [3] examined the effect of precompression time on staple quality in ex vivo porcine stomach using an Ethicon Endopath linear cutter. Even with a looser definition of “optimal” formation (including “B,” “R,” and “D” shapes), results were striking (See Figure 5):
- 53% optimal staple formation with 5 minutes of precompression
- 29% with 1 minute of precompression
- 17% with no precompression
- In the thickest tissue (5.25 mm), only ~15% optimal formation even after 5 minutes
It is worth noting that most surgeons struggle to maintain even a 15–30 second precompression interval in the operating room; a full minute—let alone five—seems like an eternity in the OR.
Optimal staple formation by precompression time
Ex vivo porcine stomach study using Ethicon Endopath linear cutter. "Optimal" defined as B, R, or D shaped. Mean tissue thickness ~4 mm. Source: Nakayama et al., Surg Endosc 2011.
Figure 5
Powered Versus Manual Staplers (Kimura & Terashita, 2016)
Using ex vivo porcine small bowel stacked to simulate human intestinal wall thickness, the authors compared powered and manual Ethicon linear cutting staplers [5]. Although the powered device was superior, the absolute performance of both was poor (See Figure 6):
- Powered stapler: 37.5% optimal staple formation
- Manual stapler: 5–8% optimal formation
Even the “better” powered device fell short of optimal formation in nearly two-thirds of staples fired.
Optimal staple formation: powered vs. manual stapler
Ex vivo porcine small bowel, stacked to simulate human intestinal wall thickness. Ethicon linear cutting staplers compared. Source: Kimura & Terashita, Surg Obes Relat Dis 2016.
Figure 6
Bronchial Closure with Manual Staplers (Okami et al., 2017)
Okami and colleagues conducted a randomized study comparing equal-height staples with graduated-height staples (Medtronic) in bronchial closure during pulmonary resection in 61 patients [2]. Staples were graded 0–4, with 4 representing a perfect “B.”
Among 1,144 staples evaluated:
- Only 18% of all staples achieved a perfect score of 4
- Mean score across all staples: 2.4 out of 4
- There was more staple line bleeding with the graduated-height staples, and more air leaks with the equal-height. Neither of these reached statistical significance.
- Patients who experienced air leaks had a mean staple score of only 0.98, confirming that poor formation translates directly into clinical complications
Bronchial Closure with Powered Staplers (Nakao et al., 2026)
A prospective 2026 study from Tokyo assessed an Echelon Flex Powered Plus stapler during lower lobectomy in 80 consecutive patients [6]. Staples were scored 1–3, with 3 representing a well-formed “B.” Among 1,289 staples evaluated (See Figure 7):
- Only 11% of staples achieved a perfect score of 3
- 23% scored 1–1.5 (poorly formed)
- Median score for all staples: 1.92
In this study, sponsored by the manufacturer, more than twice as many staples were poorly formed than well formed.
Staple score distribution
Prospective study of bronchial closure during lower lobectomy (n=80 patients, 1,289 staples). Echelon Flex Powered Plus stapler. Score of 3 = well-formed "B". Source: Nakao et al., Asian J Endosc Surg 2026.
Figure 7
Lexington Medical AEON Surgical Stapler: Internal Data [7]
Internal testing of the AEON endoscopic manual surgical stapler in ex vivo porcine stomach at multiple tissue thicknesses demonstrated substantially superior staple formation compared to Medtronic and Ethicon devices:
Proper B-formation rate by tissue thickness
Testing performed with ex vivo porcine gastric tissue. Thickness measured at 8 g/mm² compression. Data on file (MC-021020).
Clinical Outcomes
Better staple formation leads to better clinical outcomes; the data substantiates it. Across multiple surgical subspecialties, the AEON surgical stapler demonstrates performance advantages that translate into measurable patient benefit.
Bariatric Surgery
Three separate studies evaluated staple line bleeding in sleeve gastrectomy:
- In 60 patients, the AEON stapler produced significantly lower staple line bleeding scores versus the powered Echelon (2.1 vs. 2.6, p=0.01). The AEON group had no episodes of profuse bleeding, while 7% of Echelon staple lines bled profusely. Fifty percent of AEON patients had no bleeding at the fundus versus 23% in the Ethicon group [8].
- Against a Medtronic graduated-height stapler, AEON showed significantly lower bleeding scores in 4 of 5 anatomic regions examined [9].
- In a 250-patient study, an AEON stapler (buttress used in only 17% of high-risk cases, no Tisseel) demonstrated non-inferiority to a Medtronic stapler used with buttress material and Tisseel hemostatic agent in all patients. There were 2 misfires and 2 malfunctions in the Medtronic group; none in the AEON group [10].
Hepato-pancreato-biliary (HPB) surgery
In a retrospective study of 58 patients undergoing distal pancreatectomy, the AEON surgical stapler was compared to Medtronic, with results strongly favoring the AEON [11]:
- Mean drain lipase on POD 3: 446 vs. 4,208 U/L (p=0.018)
- Pancreatic fistula rate: 20% vs. 65% (p=0.001)
- Length of stay: 6 vs. 9 days (p=0.018)
- Comprehensive complication index: 4.97 vs. 13.8 (p=0.087)
Thoracic Surgery
A 2026 study from the University of Basel compared the manual endoscopic AEON surgical stapler against the powered Echelon in 32 sides of bilateral lung volume reduction surgery (LVRS) for COPD [12].
In this study, patients that underwent bilateral LVRS had a different stapler used for each side, thus each patient served as their own control. A total of 32 sides were operated on, and, although the results were not statistically significant, the trends were dramatic:
- Air leak incidence: 35% (AEON) vs. 60% (Echelon)
- Median time to air leak resolution: 14 hours vs. 93 hours
- Time to chest tube removal: 3.1 vs. 4.9 days
Notably, the manual AEON stapler outperformed a powered Echelon device—despite existing evidence that powered staplers generally outperform manual ones [13,14].
Conclusion
Several consistent conclusions emerge from this body of evidence:
- Legacy surgical staplers demonstrate poor overall staple formation rates in challenging tissue under independent evaluation.
- When rigorously examined, clinical outcomes are meaningfully affected by stapler performance.
- The AEON stapler outperforms competing devices on both staple formation metrics and, most importantly, clinical outcomes.
- Performance advantages are most pronounced in high-stakes procedures—LVRS, distal pancreatectomy, and sleeve gastrectomy—where stapler-related complications are common due to tissue or patient characteristics which push the limits of a stapler.
- If a device excels in these high-risk settings, the benefits logically will extend to routine cases as well.
How does Lexington Medical, Inc. make a better surgical stapler with AEON?
- Lexington Medical focuses its attention on one thing, and one thing only: stapler technology. Building a better endoscopic surgical stapler is the core of what we do. Compare this to legacy manufacturers who have thousands of products in their portfolios.
- Lexington Medical spends a significant portion of its revenue on R&D to continue to improve its existing staplers and develop new ones.
- There are many critical parts to a surgical stapler—it’s not just about the staples themselves. Improving multiple key components of the device by a few percent each can have a dramatic aggregate effect. Surgeons who try our stapler for the first time remark on the ease of firing and handling of the stapler, and the overall premium feel of the product as compared to other brands.
Most surgeons are not actively thinking about surgical stapler performance because the devices they are accustomed to are “good enough”—and in many routine cases they are. The complication rates are low, no single dramatic failure draws attention, and detecting a meaningful difference between devices would require a very large prospective study that is unlikely to be conducted. But the data from challenging cases is clear, and the mechanistic rationale is sound: better staple formation leads to better outcomes.
Don’t your patients deserve better than “good enough”?
Key Takeaways
- Independent studies consistently show legacy surgical staplers achieve optimal “B” formation in well under half of staples fired, even under favorable test conditions.
- Precompression time has a measurable, direct effect on staple formation, but the precompression intervals required for meaningful improvement exceed what is practical in most operating rooms.
- Powered surgical staplers generally outperform manual staplers, yet published competitor’s powered-stapler formation rates still fall well short of consistent optimal formation.
- Poor staple formation has a demonstrated clinical consequence: patients with air leaks after bronchial closure had meaningfully lower staple formation scores than patients without.
- AEON manual surgical staplers demonstrated 99% and 88% proper B-formation at 3.5mm and 4.5mm tissue thickness in internal testing, compared to 82%/58% (Medtronic) and 92%/56% (Ethicon).
- AEON outperformed a Medtronic comparator on pancreatic fistula rate (20% vs. 65%) and length of stay in distal pancreatectomy.
- A manual AEON surgical stapler outperformed a powered Echelon device on air leak incidence and time to resolution in a University of Basel thoracic surgery study, a result that runs counter to the general finding that powered staplers outperform manual ones.
- Staple formation differences are most pronounced in challenging tissue: pancreas, liver, emphysematous lung, and thick stomach, exactly where stapler-related complications are most consequential.
Frequently Asked Questions
A surgical staple starts as a “U” and should close into a symmetric “B” when fired, sealing tissue while preserving blood flow. Formation can fail due to tissue thickness, density, calcification, incorrect reload sizing, or the stapler’s own design. Thin tissue like bowel is relatively forgiving. Thick or dense tissue such as pancreas, liver, emphysematous lung, and stomach pushes many staplers past their reliable limits, which is where formation differences between devices become clinically visible.
Definitions vary. A 2014 Ethicon-sponsored study classified several staple shapes as acceptable, though later authors consider some of those shapes suboptimal. Another Ethicon-sponsored study defined optimal formation as “B,” “R,” or “D” shaped staples. Lexington Medical’s data, consistent with other independent authors, holds staples to a stricter standard: a symmetric “B” shape as the benchmark for optimal clinical performance.
A 2011 study using an Ethicon linear cutter on ex vivo porcine stomach found optimal staple formation at only 17% with no precompression, 29% at one minute, and 53% at five minutes, using the broader “B, R, or D” definition. In the thickest tissue tested, formation stayed near 15% even after a full five minutes. Most surgeons struggle to hold even a 15 to 30 second precompression interval in the operating room.
In a randomized study of 1,144 staples across 61 patients comparing equal-height and graduated-height staplers in bronchial closure, only 18% achieved a perfect score, with a mean score of 2.4 out of 4. Patients who experienced air leaks had a mean staple score of just 0.98, directly linking poor formation to a real clinical complication.
A 2026 manufacturer-sponsored study of an Echelon Flex Powered Plus stapler during lower lobectomy evaluated 1,289 staples across 80 patients. Even with the manufacturer’s own data, only 11% of staples achieved a perfect score, 23% were poorly formed, and the median score was 1.92 out of 3. More than twice as many staples were poorly formed than well formed.
Yes. In distal pancreatectomy, AEON showed a pancreatic fistula rate of 20% versus 65% for a Medtronic comparator, with lower drain lipase and shorter length of stay. In bariatric surgery, AEON produced significantly lower staple line bleeding scores across three independent studies. In thoracic surgery, a University of Basel study found lower air leak incidence and faster resolution with the manual AEON stapler compared to a powered Echelon device.
Lexington Medical, Inc. builds surgical staplers exclusively, unlike legacy manufacturers managing thousands of products across broader portfolios. Engineering focus is directed at every component contributing to staple formation, not staples alone. Surgeons using AEON for the first time frequently note the firing feel and handling as immediately distinct from other brands.
References
- Chekan, E. and R. Whelan, Surgical Stapling Device-Tissue Interactions: What Surgeons Need to Know to Improve Patient Outcomes. Medical Devices: Evidence and Research, 2014: p. 305.
- Okami, J., et al., Randomized Study Comparing Equal Height Staples With Graduated Height Staples in Bronchial Closure. Ann Thorac Surg, 2017. 104(3): p. 1012–1019.
- Nakayama, S., et al., The Importance of Precompression Time for Secure Stapling with a Linear Stapler. Surg Endosc, 2011. 25(7): p. 2382–6.
- Yim, A.P.C. and C.M.Y. Leung, Study of Endoscopic Staple Formation by Specimen Radiography on Pulmonary Wedges. CHEST, 1995. 108(6): p. 1728–1730.
- Kimura, M. and Y. Terashita, Superior Staple Formation with Powered Stapling Devices. Surg Obes Relat Dis, 2016. 12(3): p. 668–672.
- Nakao, M., et al., Staple Formation by Endostapler and Bronchial Wall Thickness in Pulmonary Lobectomy: A Prospective Observational Study. Asian Journal of Endoscopic Surgery, 2026. 19: p. 1–9.
- Surgical Stapling for Thoracic Surgery. Lexington Medical. https://lexington-med.com/clinical-thoracic/. 2026.
- Redmann, J.G., et al., Improving Hemostasis in Sleeve Gastrectomy with Alternative Stapler. JSLS, 2020. 24(4).
- Raftopoulos, Y., et al., Prospective Randomized Comparison of Linear Endostaplers During Laparoscopic Sleeve Gastrectomy. Obes Surg, 2022. 32(10): p. 3472–3480.
- Hogan, G., et al., Comparative Analysis of Hemostasis and Staple-Line Integrity between Medtronic Tri-Staple(TM) with Preloaded Buttress Material and the AEON(TM) Stapler in Bariatric Surgery. JSLS, 2024. 28(2).
- Sheen, A.J., et al., Preliminary Experience in Laparoscopic Distal Pancreatectomy Using the AEON™ Endovascular Stapler. Front Oncol, 2023. 13: p. 1146646.
- Macharia-Nimietz, E.F., et al., Efficacy of Non-Powered Stapler in Lung Volume Reduction Surgery of Severe Lung Emphysema: A Prospective Randomized Single-Blinded Monocentric Study. Interdisciplinary CardioVascular and Thoracic Surgery, 2026.
- Martín-Arévalo, J., et al., Current Evidence on Powered Versus Manual Circular Staplers in Colorectal Surgery: A Systematic Review and Meta-Analysis. International Journal of Colorectal Disease, 2025. 40(1).
- Ho, S.Y.A., V.K. Muthiah, and K.V. Tay, Comparing Surgical Outcomes of Powered Versus Manual Surgical Staplers: A Systematic Review and Meta-Analysis. Langenbecks Arch Surg, 2024. 409(1): p. 331.
