One Size Fits All: The Case for Dynamic Trocars

When I was shopping around for bicycle helmets, I noticed that all of the helmets on the racks had adjustable straps and head rings. This made my shopping a lot more convenient; if all these helmets could fit a head as small as mine, then all I really needed to care about was aesthetics. The one-size-fits-all helmets afforded me versatility and choice.

One-size-fits-all is a novel concept in the trocar market - so novel, in fact, that there are only two in existence. But is there value in this novelty?

Trocars, commonly referred to as ports, are used in laparoscopic, or keyhole, surgery to provide access into the abdominal or peritoneal cavity. Their design is quite simple: the obturator penetrates into the cavity, the cannula creates a portal for laparoscopes to go into the cavity, and the seal prevents gas from leaking from the cavity. 

Trocar designs can be divided into two main types: a cutting trocar has a blade that cuts through tissue layers and a dilating trocar has a blunt (bladeless) tip that separates and dilates the tissue upon insertion.

Dilating trocars have an advantage over cutting trocars. Dilating trocars can work with smaller incisions, producing fascial defects that do not require closure. On the other hand, cutting trocars require incisions that will fit the device’s predetermined size. A study by Mordecia et al. in the Surgical Endoscopy journal investigated the effects of using cutting trocars or dilating trocars has in the repairing of transabdominal preperitoneal hernia, an abdominal tissue that protrudes through the abdominal wall post surgery. The study concluded that dilating trocars significantly reduce the postoperative analgesic (pain relief) requirement and hospital stay with a quicker return to normal lifestyle. These findings are supplemented by another study by Ciscar et al., which found that 5.5% of trocar-site incisional hernia occurred in 5mm trocar sites while 94.45% of such hernia were located in 10mm trocar sites.

If smaller incisions are associated with less trocar-related complications, then have we reached the pinnacle of trocar design with dilating trocars? Not quite yet. Dilating trocars along with cutting trocars have static ports, meaning they only accept a certain-sized instrument. A trocar with a 5mm port can only take 5mm scope. If surgeons start with a 5mm trocar but need to use a larger scope, then they would switch out the smaller trocar for a larger one. This disrupts the surgical workflow and increases the likelihood of hernias.

Trocars with dynamic ports could solve such issues. They follow the same principle that made dilating trocars so innovative – a small incision that gets expanded while it remains inserted into the body cavity. But these trocars can only dilate at the site of the cavity. A one-size-fits-all trocar can accommodate for different sizes of instruments. Dynamic trocars could fulfill the role of dilating trocars in reducing hernia rates and operating times. It also improves surgical workflow to eliminate the need for switching out trocars.

There are two trocars with dynamic ports: the VersaStep Bladeless Trocar and the Xpan Universal Trocar System. The VersaStep Bladeless Trocar utilizes Step Radial Dilation technology and a mesh sleeve to accept scopes of different diameters.  The mesh sleeve is expanded to its max diameter during surgery, making it a single-use trocar. The Xpan Universal Trocar System utilizes a rigid threaded expandable cannula and a durable expandable sheath. The system works by starting with a 3mm blunt tip, followed by 5mm and 12mm optical tips. The small 3mm incision reduces patient trauma and can be dilated as the cannula expands.

Although VersaStep Trocars can dynamically be used with different scope sizes, they are not quite one-size fits-all trocars. They comes close, but their mesh sleeve is prone to breaking. The Xpan Trocar better suits the description of a 3-in-1-sized trocar. Neither trocar is widely used in standard operations. In fact, the Xpan Trocar only recently received FDA 510(k) clearance in June of this year.

After more research, using phrases like “expandable trocar”, “dynamic trocar”, and “dynamic access port”, I found the MindsEye™ Expandable Port by Cerevention. This medical device was launched on the market in August 2022 for use by neurosurgeons in deep brain access and visualization procedures to treat stroke, cancer, and other neurological conditions. It requires a small incision in the tissue that can then get dilated during surgery. This expandable port is revolutionary in neurosurgical workflows as it maximizes the visual field without compromising more tissue than necessary.

Trocar patents have been in use for ages, with the first patents dating back to the 19th century. Yet in the last two centuries, a one-size-fits-all trocar is yet to exist in the current market. What have bicycle helmet companies figured out that trocar companies have not yet?