Onlay vs Sutured Duraplasty: How to Present a Collagen Membrane

Onlay duraplasty places a collagen graft over the dural opening so that it overlaps the edges without sutures; sutured duraplasty fixes the graft to the dural edge with stitches. Both are established techniques. A good presentation explains each one neutrally, shows which DESU membrane fits it, and leaves the choice to the surgeon.

This matters because reps sometimes present a collagen membrane as if one technique were simply better. Experienced surgeons will dismiss that quickly. They choose a technique according to the defect, the location, the condition of the native dura and their own training, and they expect the product conversation to respect that.

What are the two techniques?

Onlay duraplasty

In onlay technique, the surgeon lays the graft over the dural defect so that it overlaps the healthy dura around the opening. The graft is held in place by contact with the underlying tissue and by the surrounding structures, and in some cases by a sealant applied according to the surgeon's protocol. No sutures pass through the graft.

Collagen matrices used this way are intended to act as a scaffold over which the patient's own tissue can grow. The literature on collagen onlay grafts goes back decades; one early clinicopathological study of a collagen sponge used as a dural graft was published in the Journal of Neurosurgery in 1995.

Surgeons who favor onlay technique often mention that it can save time, avoids needle holes through the graft and may be convenient where the dural edge is thin, irregular or difficult to reach with a needle. Others are more cautious with onlay repair in locations where they expect higher CSF pressure or movement, and prefer to add fixation there.

Sutured duraplasty

In sutured technique, the graft is cut to size and sewn to the dural edge, usually with a running or interrupted suture. The aim is a secure, close approximation between graft and dura. Many surgeons regard suturing as their default when the anatomy allows it and the defect sits in a location where they want mechanical fixation.

Sutured repair takes more time and requires a graft that holds sutures well. In return, the surgeon gets a graft that is fixed in position. Some combine suturing with a sealant over the suture line, as part of a layered closure.

When do surgeons choose one or the other?

There is no universal rule, and a rep should not invent one. The factors surgeons commonly weigh include:

• The size and shape of the defect, and whether the native dura is healthy enough to hold sutures.
• The location: convexity, skull base, posterior fossa or spine each present different access and pressure conditions.
• The surgeon's training and the habits of their department.
• The time available and the condition of the patient, for example in trauma.
• Whether a sealant or additional tissue layers will be part of the closure.

Some surgeons combine techniques: an onlay graft beneath or above a sutured layer, for instance. Others always suture when they can. Your job is to understand which pattern applies to the surgeon in front of you.

How do DECOLL and DURASHEET map to the two techniques?

DESU's two collagen membranes are made from the same material, pure Type I bovine collagen, and differ in their intended use.

For an onlay-oriented surgeon, DECOLL is the product to show. For a surgeon who sutures, DURASHEET is designed for that use, and its two usable surfaces mean the team does not need to check orientation before placement.

Always confirm the indications and handling instructions in the current IFU. Do not suggest a technique or a use that the IFU does not describe.

How should you present both uses in one meeting?

A short, structured presentation works better than a product pitch. One format that keeps the discussion clinical:

• Ask how the surgeon closed the dura in their last three cases that needed a graft.
• Summarize the two techniques in one sentence each, without ranking them.
• Show the membrane that fits their answer first, and let them handle it.
• Mention the second membrane briefly, as an option for cases where they use the other technique.
• Leave the IFU for both products and agree on how an evaluation would work.

Keep the samples or demonstration units clearly labeled and handled according to the hospital's rules. A surgeon who handles the material will learn more in a minute than from any slide.

What questions will surgeons ask about each technique?

Surgeons tend to test the rep on details. Prepare for these:

Questions about onlay use

"How much overlap do you recommend?" and "Do I need a sealant?" are common. The answer is to point to the IFU and to the surgeon's own protocol. Overlap and the use of sealants are clinical decisions; the rep should not prescribe them.

Questions about sutured use

"How does it hold a suture?" and "Can I trim it?" are typical. Let the surgeon judge suture handling on a demonstration unit, and confirm trimming instructions from the IFU. Avoid quoting any strength figures that DESU does not publish.

Questions about evidence

Collagen dural grafts have a long publication history, including clinical series on collagen-only matrices used as dural substitutes. A rep can mention that such literature exists and point surgeons to it, but should not summarize results as if they applied directly to a specific product. If a surgeon asks for product-specific evidence, the right answer is to ask DESU for the technical and clinical documentation available for DECOLL or DURASHEET and to deliver exactly what the manufacturer provides.

That discipline protects the rep. A surgeon who catches a rep stretching a study will discount everything else they say, while a rep who separates general literature from product documentation is treated as a reliable source.

What should the OR team know about each technique?

The scrub nurse and circulator see the technique from a different angle. For onlay use, they need to know which size the surgeon usually wants, whether a sealant will follow, and how the graft should be passed without folding it. For sutured use, they also need the right suture and needle on the back table before the graft is opened, so the surgeon is not waiting with a membrane in hand.

A short in-service that covers both techniques, with the two products side by side, helps the OR team anticipate the surgeon's next step. It also reduces the chance that the wrong product or size is opened. DESU's specialists can help prepare training material for this purpose.

Why carrying both helps the department

A department that uses both techniques benefits from having two clearly defined products from the same manufacturer, made from the same material. Supply chain sees one vendor; surgeons see a product for each technique; OR staff learn one family of products rather than two unrelated brands. That is a simpler story for a value-analysis committee than "we need another patch".

For the OR team's side of the story, our guide to dural graft handling in the operating room covers preparation and passing.

Talk to a DESU product specialist

If you are a distributor, an agency or a hospital team comparing onlay and sutured options, DESU's product specialists can send the IFU for DECOLL and DURASHEET, explain each product's intended use and discuss your market. Write to sales@desu.tr, use the contact page, or request a quote.