Cubital Tunnel Release (Cadaver)
My name is Asif Ilyas. I'm a Professor of Orthopaedic Surgery and the Program Director of Hand Surgery at the Rothman Institute at Thomas Jefferson University in Philadelphia. Today we will be going over a cubital tunnel release procedure. Cubital tunnel syndrome is a very common compressive neuropathy of the upper extremity. It's the second most common compressive neuropathy after carpal tunnel syndrome, and fundamentally, it involves compression of the ulnar nerve as it traverses the cubital tunnel, which is behind the medial epicondyle of the elbow. When you have a symptomatic cubital tunnel syndrome, which you will notice is numbness and tingling in your small and part of your ring finger, and in advanced cases, you'll also develop some weakness, and altered dexterity, and even atrophy of the intrinsics of your hand.
There's 2 broad ways to approach cubital tunnel syndrome. Surgically, one is to do an in situ release where the nerve is released right where it lies - also known as a neuroplasty of the ulnar nerve - or the second broad way of treating this is with a transposition where you actually neurolyse the ulnar nerve and then transpose it anteriorly. Now within each of those broad categories, there's subcategories, so for this video, we will be looking at specifically a cubital tunnel release. So cubital tunnel release can also be further broken up into an extensile-open, a mini-open, and an endoscopic technique, and I'll be showing you the mini-open technique for decompressing the ulnar nerve in the cubital tunnel.
Okay, so now we're going be addressing ulnar neuropathy of the elbow, also known as cubital tunnel syndrome. You'll notice the arm is flexed slightly, externally rotated. I'm looking at the posteromedial - posteromedial aspect of the elbow. The ulnar nerve is going to be right behind the medial epicondyle, and it is palpable in the specimen here. Now to manage, surgically, ulnar neuropathy of the elbow, you have 2 ways you can approach this. You can do what is called an in situ cubital tunnel release or an ulnar nerve transposition with neurolysis. Either way, the incision is placed in this aspect of the elbow, behind the medial epicondyle.
So I'm going to mark out both incisions to kind of share - to discuss how we go about this. So if you're doing a - a ulnar transposition, you bring the elbow straight. You feel the epicondyle here. The tendency is to bring the incision anterior to the epicondyle, but recognize that you'll be away from your nerve and also increase the odds of injury inadvertently to the branches of the medial antebrachial cutaneous nerve.
So with the elbow extended, I find it helpful to make a relatively straight incision. Behind the elbow, which is the path of the ulnar nerve. If I'm doing an ulnar transposition, centered on the medial epicondyle, I'll - my incision will go anywhere from 6 to 8 cm distally, and similarly, about 6 to 8 cm, maybe 6 to 10 cm, proximally. Now, if I'm doing a cubital tunnel release, I can use the same incision; however, I can also make a smaller incision - what I refer to as the mini-open technique. And I'll use the same location on my incision, but I'll flex up the arm a little bit more to get a sense of where it is. And I place the incision directly - behind the medial epicondyle - like so. If I'm taking the transposition, I'll go the full length.
So we're going to proceed with a cubital tunnel release procedure through a mini-open technique. So here's my incision. We're going to get started. Luckily, besides the nerve itself, the ulnar nerve, there's not too many significant hazards, and one of the advantages of placing the incision somewhat posteriorly - I avoid branches of the medial antebrachial cutaneous nerve, which typically come across the epicondyle and just anterior to it. So I'm posterior to it, so I should be away from those hazards. I'm intentionally making my incision a little bit anterior to the epicondyle to not inadvertently injure the ulnar nerve. Now it's helpful to examine the nerve beforehand and make sure the ulnar nerve is stable, behind the epicondyle. That's important for a couple reasons. One, if it's unstable, it may have subluxed into your surgical field. And two, it helps in your decision-making of whether you do a transposition versus an in situ release. Our understanding of the evidence so far is that one has not been shown to be superior than the other with the current best evidence available to us. However, one of the reasons to do a primary transposition instead of an in situ release is a subluxing - a preoperatively or postoperatively subluxing.
Okay, so - there’s a couple ways to find the nerve quite easily. One is just directly behind the medial epicondyle, or two is behind the intermuscular septum. So here's the nerve, right there. It's very superficial. It's quite easy to find. Now I'm going to expose it a little bit better, but just to get a relationship of the epicondyle - ulnar nerve coming across it.
So, remember when you're doing a cubital tunnel release surgery - you're not neurolysing the nerve, you're not doing a transposition. You're doing a neuroplasty. There's a tendency, or a habit, with this surgery for people to do a neurolysis 360. What that does is 2 things. It creates 2 problems. Problem number 1 is it makes the nerve unstable. And number 2, it devascularizes the nerve. Think of a cubital tunnel release no different than a carpal tunnel release, where you're just releasing it where it lies. Now I changed my scissors to a Metz. And once I have it adequately exposed proximally, I'll just slide and make sure we have a great view of it above and below. I'll do a release right where it lies. So that's the easy part of the release - is the proximal part. So if you take a look now - you'll see the nerve - nicely - released - no more fascia. What I released was the arcade. Okay, so now - we're going to do the distal part of the release. I'll just give myself a little bit more skin.
Good. Once the nerve has been decompressed proximally, we can work our way distally. And the next thing you'll find - just to orient everyone, this is the medial epicondyle. This is the olecranon. This is the ulnar nerve. So, we're going to work our way distally. And typically, the path of the nerve across the cubital tunnel, or under Osborne's ligament, is the tightest. And that's where we're working now. And whenever I cut, I always make sure that I have the nerve in view. And again, I'm not doing a - neurolysis of the nerve, I'm doing a neuroplasty.
And I'm going to take this distal, and the question always comes up - how distal do you go? You go until you get to the 2 heads of FCU, the flexor carpi ulnaris, and you make sure that it is decompressed as it travels through. So here's a good view of that plane, just to show you. I'm going to grab a Freer for a second. So just to orient, everybody - so, you'll see the nerve deep, and you see the path of the nerve underneath it. You'll see the fascia of the FCU starting, and my retractors are above that fascia - the fascial plane. And the release that we like to do - is basically - at this level - right here. Let me see if I can put a retractor there to show that a little bit better. It's hard to do by myself here. Unfortunately, I should have had somebody. Just to show everyone the plane. That's the plane below. That's the plane above. And the release is like this. Gentle slide. And cut, and the nerve is free. And you want to visualize - going deep. Make sure it's adequately decompressed. There's often a deep investing fascia - you want to confirm that it is released.
Once adequately released, and satisfied that it's released, you range the elbow - flexion and extension - to make sure that the ulnar nerve does not sublux, or dislocate, over the medial epicondyle. A little bit of rolling and perching is typical, but you do not want it to sublux. And you'll see here in this case that the ulnar nerve is very stable. Once released, you'll see how it tends to pouch more and almost roll freely more, but it should not dislocate or sublux out.