This is one of those “for want of a nail, the kingdom was lost” stories.
How often do you pick up the suture passer, use it, admire your good work and put it aside—barely pausing to think about it even once?
Always? You’re not alone.
Well…maybe it’s time to think about it.
There’s been an uptick in the number of FDA MAUDE reports about suture passers. We’re not talking a large number—certainly not in relation to the hundred thousand suture passers in use—but enough to make us stop and consider the simple, but essential suture passer.
MAUDE stands for Manufacturer and User Facility Device Experience (MAUDE) and is the FDA’s publically available adverse events database for medical devices.
The problem appears to be pieces of the nitinol needle breaking off.
Again, with literally hundreds of thousands of suture passers working flawlessly day in and day out, this has not risen to a hair-on-fire moment, but it does put suture passers in the spotlight. No one wants to leave a needle tip in the patient.
Attending to the “needle tip” can save the kingdom, in other words.
Suture Passers
Suture passers help surgeons put sutures through tissue, like torn tendons, and reattach it to bone when using a suture anchor implant. There are many types of suture passers. The simplest non-orthopedic suture passers are effectively large sewing needles made of stainless steel.
In orthopedics, arthroscopic surgery fueled the popularity of suture passers since they allowed surgeons to work in extremely tight spaces during a minimally invasive surgery.
Some of most complex suture passers are used in orthopedic arthroscopic operations. These suture passers have two jaws which are known as graspers since they allow surgeons to grasp and manipulate tissue while also passing suture carrying needles in, through and out of the tendons. These suture passers use disposable, single-use nitinol needles and typically come with formed plastic handles.
Here’s a picture.
In orthopedics, one of the most important uses for suture passers is for arthroscopic rotator cuff surgery.
Recent MAUDE Reports
Two of the most popular orthopedic suture passers (Arthrex, Inc.’s Scorpion and Mitek’s ExpressSew III) have more than 800 adverse events reported since 2006 in the MAUDE database. For the first three months of 2016 there have been more than 52 adverse reported in the MAUDE database for these two popular orthopedic suture passers.
A typical adverse event is this one, which was reported March 8, 2016.
“Event Description: It was reported that during a rotator cuff repair, the surgeon was using the scorpion device and rapidly firing the scorpion needle into the cuff. Sales rep states the surgeon said he thought something was wrong with the scorpion, but the suture was passed. Upon inspection, the needle tip was still attached and everything was fine. He passed the next suture forcefully, but again it was passed. Once the surgeon finished the repair and was closing the incision site the rep who was present in the case asked to examine the scorpion and discovered that the tip of the needle was gone. Sales rep informed the surgeon; an x-ray was taken and confirmed the tip is in the patient. The surgeon did not want to re-open the patient to locate the tip.” Link: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/detail.cfm?mdrfoi__id=5534102
Although leaving a piece of nitinol in the patient is not good, it does not raise biocompatibility or other issues. That’s because nitinol, which is comprised of nickel and titanium, has been used as implant material for decades and is known to have excellent biocompatibility, very high corrosion resistance and excellent cytocompatibility.
There have been many successful nitinol implants—among them the Simon Nitinol Filter (SNF) and the Mitek bone suture anchor. The Simon Nitinol Filter is an umbrella shaped device deployed via the shape memory effect to entrap blood clots in the vena cava. The SNF was developed in the 1970s.
Mitek nitinol suture anchors revolutionized the field of orthopedic surgery by providing a secure, stable attachment for tendons, ligaments, and other soft tissue to bone. Since commercialized by Mitek in 1989 for shoulder surgery, these nitinol anchors are used in approximately 25 orthopedic applications and one urological application.
So, the adverse event of leaving the nitinol tip of the suture passer needle in the patient, hasn’t raised concerns about lack of biocompatibility or corrosion.
Non-Nitinol Suture Passers
But…you still don’t want to leave a piece of your suture passer needle in the patient.
Nitinol, as an alloy of nickel and titanium, has the ability to change shape when reaching body temperature (and return to its original shape when cooled). Stainless steel does not. But that shape changing ability has made fatigue failure of nitinol devices a constant subject of discussion. That temperature driven flexibility, it is thought, exposes the metal to greater fatigue strains than are other metals.
We tried to find a non-nitinol suture passer for orthopedic indications and could only find one. That product, called the Cobra Antegrade Suture Passer only just recently—as in March 2016—filed for a Utility and Method patent. It’s made by Strauss Surgical of Miami, Florida. According to the company, it had been in development since 2010.
Strauss CEO Charlie Bourland had this to say about his non-nitinol suture passer when we contacted him:
“We are the only company that has pursued commercializing a mechanical, non-nitinol suture passer. We are also the only company which does not rely on a disposable needle. When we started this project, our goals were to reduce procedure costs while also addressing the clinical shortcomings of nitinol.”
“We wanted a suture passer which would not have needle breakage, would not migrate obliquely the way nitinol needles can, would pass through thick or even calcified tendons, would reduce medical waste and cut surgical inventory costs.”
According to Bourland, the key to meeting those goals was to develop a proprietary stainless steel alloy which is hardened prior to electric discharge machining (EDM) and produces a needle which is curved in its natural state.
Hardened stainless steel, said Bourland, gives his Cobra Suture Passer’s needle a strength which is about 4x greater than disposable nitinol needles. A needle that strong, said Bourland, can pass through thickened or calcified tendons.
Here’s a few pictures of the Cobra, courtesy of Strauss Surgical.
Procedure Costs
There are about 1.4 million rotator cuff procedures performed worldwide and surgeons use approximately 100, 000 mechanical suture passers to pass sutures through tendons in those cases.
In the United States, for rotator cuff surgery, the single-use nitinol needle can sometimes comprise up to 17% of the total cost of an operation. The big costs are the anchor implant and that usually makes up more than half of the total cost. However, the nitinol needles are the second biggest cost behind the anchor implant. With capitated reimbursements, a reusable device like the Cobra can help save hospitals and surgery centers money.
But suture needles deployed using a nitinol suture passer—which is essential for arthroscopic or MIS (minimally invasive surgery)—could wind up becoming a much larger cost item, particularly if at the end of the case they leave a piece of the needle behind in the patient.
No doubt, if this grows as an issue, suppliers will begin testing stainless steel suture passers or other designs which could eliminate the risk of nitinol fatigue and breakage.
For want of a simple, unbreakable suture passer needle….
