This video demonstrates an end-to-end epineural nerve repair in a rat model. Microsurgical technique is critical in these repairs to allow nerve regeneration to be unhindered. In real clinical practice, the repair would be completed tension-free. For orientation, proximal is to the left of the screen, while distal is to the right. So, when doing a nerve repair, you can look at the vessels and try and match them up proximally and distally. You can also look at the fascicular structure of the nerve by turning the nerve on end. You can see there's one large fascicle and one smaller fascicle, which we're going to match up distally to the smaller and larger fascicle. So, bringing the two ends together, we can see that those are going to match up nicely, giving us a reasonable repair. So, I'm going to trim the ends of the nerves. As you can see, there's bulging axons, and I want to trim it flush with this epineurium. So, because I'm taking this out, I can touch it. So, I just simply lift it up and gently trim with my assistant, giving me a little bit of counter-traction. I want to leave the epineurium, but I'm trimming this bulging axoplasm. Maybe a little more, just grab this stuff right here. That's good. See how I kind of push the epineurium back so I don't cut that, because I actually want that layer. Okay, that's good. Okay. So, in picking up and setting the needle, I'll grab the suture right at the hub of the needle and then stabilize, especially if instruments are magnetized. I'll stabilize the needle along some soft tissue, gently grab the needle. And with microsurgery, I'm holding the needle, oh, probably about 50-50 or 60-40, instead of further back. It gives me a little more control. And then I gently turn the needle so I have this oblique angle here, and I find it easier to place my suture. I actually tend to grab the epineurium gently when I take my stitch, and I want to go through epineurium only. So I'm just skimming along the surface and avoiding going through the axons themselves. And I gently ease the needle around, grabbing it again. I can provide myself some counter-tension here and gently pull it through the epineurium, trying not to damage the inner nerve fibers. Again, re-grabbing my needle, resetting, bringing the nerve ending, checking to make sure I have the appropriate fascicular orientating small fascicle here, large fascicle here, gently picking up the epineurium, using the needle to get into that edge of epineurium, and gently putting my stitch through, not damaging the nerve fibers themselves. And re-grabbing the needle, following the curve, bringing it back along the length of the nerve, providing some counter-tension to avoid ripping the nerve tissue. Some people like to do a single suture. I tend to do a surgeon's knot on my first. I'll have my assistant gently grab the epineurium and bring both ends of the nerve together as I tie my knot to help with some of the tension, although obviously the repair should not be done under tension. And then I will gently lay my knot down, stay down on the surface, and not too tight. You can see there's almost a gap there because I want to gently oppose the nerve ends and not squinch them together, bringing fascicles outside of my repair line. So really gently bringing them together so the two ends of the nerve are just kissing and not strangulated against each other. And then I'll do my remaining standard knots, being very carefully to not bring it down too far and squinch the nerve endings together. So we'll cut one end, and then I leave one end long so my assistant can gently hold the nerve so I can place my additional sutures. So I generally place two 180-degree sutures so I can flip the nerve without disrupting the repair to do the back wall suture. So gently retract for me, and then I will again gently grab the epineurium. And sometimes I can take a stitch in one, but again I want to be very careful to match my fascicles and also keep that orientation of the vasculature on the surface of the nerve which can really help orient the repair. And again I will do a surgeon's knot first to really lock down my repair. Gently grabbing the epineurium on both sides. You can let go of this one. And then bringing the knot down, but again not too tight Sometimes I'll even pull it apart a little bit so it's an air knot. Locking it on that second stitch and making it not too tight. Go ahead and cut for me. We've completed our front wall repair. Now we're going to gently turn the nerve over so we can get to the back wall repair. And I'll pass the stitch to my assistant so they can gently hold it in the turned over position. And then we'll gently take just a little bit of epineurium on either side to gently oppose the nerve ends. Move it back this way. There you can let go. And I'll gently pull the suture parallel to my repair. And then tie my last knot down. Gently bringing the epineurium, approximating the epineurium, but not bringing too much tension or bringing the nerve repair in too tightly. So my second stitch will lock it down, but not too tightly. And then we've completed our repair. And you can cut both of those. And then just relax on that. We'll turn the nerve back over into its proper orientation and finish trimming up our suture end now that we know our repair is completed. So there's a reasonable quality nerve repair. The epineurium is just gently kissing and not too tight.

end-to-end epineural nerve repair

microsurgical technique

nerve regeneration

tension-free repair

axons and epineurium trimming