Ulnar Nerve Transposition (Cadaver)
Table of Contents
- Cubital Tunnel Syndrome Overview
- Surgical Technique
- Postoperative Management and Rehabilitation
- Postoperative Outcomes
- Statement of Consent
Ulnar nerve transposition is a surgical procedure performed to treat ulnar nerve compression of the elbow, also known as cubital tunnel syndrome. This procedure is utilized after both non-operative management and in situ decompression fails, or if these procedures are deemed inappropriate based on patient pathology or ulnar nerve instability. Transposition of the ulnar nerve involves not only decompression of the nerve but also its anterior repositioning to reduce compression and irritation while maintaining nerve integrity. This video demonstrates, on a cadaver arm, the operative technique for performing an ulnar nerve transposition using either a subcutaneous or a submuscular technique.
A 55-year-old male presents to you with sensitivity in his right elbow. He reports that the pain occurs on the posteromedial aspect of the elbow, and it is particularly bad when he flexes his elbow, such as when he is using his cell phone. He describes the feeling as a 5 out of 10 “aching” pain and says that it is sometimes accompanied by a sharp tingling sensation in his little finger and ring finger. He is also concerned because he feels his right-hand grip has recently become weaker. The patient’s past medical history is significant for an in situ cubital release performed on the right elbow 1 year prior for treatment of similar symptoms. The patient states he is particularly frustrated because the pain often wakes him up at night if he bends his arm in his sleep, and he cannot get a decent night’s sleep.
Cubital tunnel syndrome is seen with a slightly higher incidence in males than females, and increasing incidence is seen with increasing age in both genders.1 Individuals that perform repetitive or prolonged activities requiring the elbow to be in a fixed bent position are at an increased risk for developing cubital tunnel syndrome.2
Physical exam findings will vary based on the etiology and severity of the nerve compression. When the arm is moved through a full range of flexion and extension, the ulnar nerve may be observed subluxing over the medial epicondyle. There may be visible muscle atrophy of the affected hand around the little finger and ring finger, as well as clawing. This can be accompanied by decreased sensation in these fingers. Swelling and/or a cyst may be observed by the medial epicondyle.3 A positive Froment’s sign, indicating a compensatory thumb flexion during a pinching motion, is characteristic of ulnar compression. Additionally, persistent little finger extension and abduction, known as a positive Wartenberg’s sign, suggests ulnar nerve compression. Motor testing that reveals a weakened grasp and/or pinch also supports this diagnosis.3,4
Cubital tunnel syndrome is due to compression and irritation of the ulnar nerve at the elbow by the medial epicondyle. The cubital tunnel is a narrow space that the nerve must traverse with very little surrounding soft tissue for protection. Often, the exact cause of this nerve irritation is not known, but causes include holding a phone to the ear extensively, leaning on the elbows, an elbow cyst, and elbow arthritis. If the ulnar nerve remains compressed for an extended period of time it can lead to irreversible muscle wasting in the hand as well as ongoing pain and decreased function of the affected elbow and hand. For patients presenting with mild or moderate nerve compression, first-line treatment involves discontinuing activities that increase nerve compression, taking NSAIDs, and wearing a padded elbow brace or splint. If the nerve is severely compressed or non-surgical treatment methods are ineffective, then surgery is indicated. Surgical procedures include cubital tunnel release and anterior nerve transposition.3
X-ray can be used to visualize the bony structure of the elbow and reveal any bone spur or arthritis that may be responsible for the nerve compression. Nerve conduction studies are useful in determining the condition of the ulnar nerve, where the compression is occurring, and whether or not there is any associated muscle damage.
This procedure is performed under general or regional anesthesia using a sterile tourniquet. Position the patient supine with the arm externally rotated and flexed slightly so that the posteromedial aspect of the elbow is exposed. Disinfect the incision site, then fully extend the elbow and palpate the medial epicondyle to locate the ulnar nerve. Mark out the location of the ulnar nerve posterior to the medial epicondyle, extending 6–10 cm in both the proximal and distal directions.
Flex the arm slightly to visualize the path of the nerve. Create a longitudinal incision directly behind the medial epicondyle along the marked path. Dissect proximally to the medial epicondyle, down through the subcutaneous tissue. Open the incision and cauterize blood vessels as necessary. Identify the ulnar nerve proximal to the medial epicondyle.
Release the proximal ulnar nerve arcade using a spreading motion with scissors. Push the nerve around as needed to perform the release, but avoid grabbing it to prevent damage to the nerve or its accompanying blood vessels. Confirm the nerve is mobilized. Continue making a longitudinal incision distal to the medial epicondyle, and confirm the nerve is mobilized. Insert retractors at both the proximal and distal ends of the incision. Release the distal ulnar nerve arcade and confirm the nerve is mobilized. Take care to avoid cutting through any nerve branches or vessels. If one of these structures is inadvertently cut, be sure to cauterize it to prevent painful neuromas or excessive bleeding. Release the fascia between the 2 heads of the flexor carpi ulnaris (FCU), making sure to release the fascia in line with the nerve. Check for any deep investing fascia, and if any is observed, spread the fascia with scissors to release. Once the cubital tunnel has been fully opened and the ulnar nerve mobilized, gently pull the ulnar nerve away from the released fascia. Maintain the branches from the ulnar nerve if at all possible, and cauterize any nerve branches that cannot be preserved.
Once the nerve is mobilized, remove the intermuscular septum from the medial epicondyle using either a knife or a cautery. Excise about a 1-cm segment so that there is a bare supracondylar ridge exposed. Take care to protect the motor nerve branch on the ulnar side of the septum. Reposition the nerve by moving it anterior so that it sits over the supracondylar ridge without interference from any external structures. Cauterize the first branch of the ulnar nerve if it is tethering the nerve and inhibiting anterior mobilization and transposition.
Subcutaneous Technique. Close the cubital tunnel to prevent inadvertent resubluxation. To do this, mobilize the posterior tissues from the triceps extension and close the tissue flaps across the interval enclosing the medial epicondyle. Apply 2 figure-of-eight sutures to complete the closure. Then create a fascial sling to hold the nerve in place anteriorly. This can be done by repositioning the posterior aspect of the FCU across the nerve, leaving the fascia attached to its origin on the epicondyle. Use a 2-0 Vicryl or equivalent to fix the sling.
Submuscular Technique with Z-plasty. Temporarily translate the nerve posteriorly. Incise the flexor pronator muscle belly in a Z-fashion to create leaflets. To do this, mark out flaps on the flexor pronator muscle origin using three parallel lines: one on the leading edge, one down the middle, and one where you decompressed the ulnar nerve. This will create a distal flap and a proximal flap. The distal flap requires some dissection off the muscle, but the proximal flap pulls off rather easily because it goes in the direction of the muscle fibers. Move the nerve to within the prepared flexor pronator muscle leaflets. Connect the muscle leaflets end to end with 1–2 figure-of-eight sutures. Take care not to stitch too tightly, or there is a risk of inadvertently creating a new site of constriction on the nerve.
Now that the nerve has been stabilized, take the nerve through an active range of motion. Release any residual tension resulting from deep investing fascia.
Wash the wound thoroughly with sterile water. Drop the tourniquet. There may be a moderate amount of bleeding, so cauterize as needed. Close the skin with 3-0 Vicryl, a running 4-0 Monocryl, and then a glue or nylon for the skin.
Apply a cast or splint to the elbow to maintain a 90° bent position for 2–4 weeks postoperatively. Physical therapy is recommended to regain strength and range of motion, as well as to help with pain management.
Ulnar nerve transposition is considered an effective long-term treatment option for patients with cubital tunnel syndrome. It is most often recommended in cases where simple in situ cubital tunnel release is contraindicated,3,5–9 such as in cases of prior elbow trauma or underlying pathology.10 Retrospective studies have shown that in patients without elbow arthritis or elbow trauma, in situ decompression is an effective option for treating cubital tunnel syndrome that carries lower risk of adverse events and recurrence than ulnar nerve transposition procedures.7,9 A 2018 prospective cohort study found that patients experienced greater surgical morbidity following ulnar transposition than decompression as measured by narcotics consumption, patient-reported disability, and persistent olecranon paresthesia. However, most of these differences were transient and resolved by 8 weeks after surgery.5
A meta-analysis of four randomized controlled trials found no difference in motor nerve-conduction velocities or clinical outcome scores between simple decompression and ulnar nerve transposition in patients without prior traumatic injuries or surgeries of the affected elbow.6 A 2015 cadaveric study showed that both subcutaneous and submuscular transposition provided a statistically significant decrease in nerve strain in full flexion, while in situ release did not provide a change in strain in either flexion or extension. These results provide evidence that an ulnar transposition may be warranted over an in situ release when strain is the underlying pathology causing ulnar neuropathy.8
Once a surgeon has deemed a patient to be an appropriate candidate for ulnar transposition, there are a few transposition techniques to choose from. The current literature provides limited insight into the different outcomes between the available techniques. A 2015 meta-analysis of the available randomized controlled trials and observational studies comparing subcutaneous and submuscular transposition techniques found no difference in the outcome of clinically relevant improvement. However, the authors found that the incidence of adverse events was significantly higher following submuscular transposition than subcutaneous transposition. The authors acknowledged that the outcomes used in the various studies were inconsistent and there were very few randomized controlled trials, so more evidence is needed on this topic in order to draw meaningful conclusions.11 Retrospective studies have found similar evidence that while both subcutaneous and submuscular transpositions effectively treat cubital tunnel syndrome, submuscular transposition is associated with higher recurrence and more complications.12,13
Nothing to disclose.
The patient referred to in this video article has given their informed consent to be filmed and is aware that information and images will be published online.
- Osei DA, Groves AP, Bommarito K, Ray WZ. Cubital tunnel syndrome: incidence and demographics in a national administrative database. Neurosurgery. 2017;80(3):417-420. doi:10.1093/neuros/nyw061.
- Adkinson JM, Zhong L, Aliu O, Chung KC. Surgical treatment of cubital tunnel syndrome: trends and the influence of patient and surgeon characteristics. J Hand Surg Am. 2015;40(9):1824-1831. doi:10.1016/j.jhsa.2015.05.009.
- Grandizio LC, Maschke S, Evans PJ. The management of persistent and recurrent cubital tunnel syndrome. J Hand Surg Am. 2018;43(10):933-940. doi:10.1016/j.jhsa.2018.03.057.
- Goldman SB, Brininger TL, Schrader JW, Curtis R, Koceja DM. Analysis of clinical motor testing for adult patients with diagnosed ulnar neuropathy at the elbow. Arch Phys Med Rehabil. 2009;90(11):1846-1852. doi:10.1016/j.apmr.2009.06.007.
- Staples R, London DA, Dardas AZ, Goldfarb CA, Calfee RP. Comparative morbidity of cubital tunnel surgeries: a prospective cohort study. J Hand Surg Am. 2018;43(3):207-213. doi:10.1016/j.jhsa.2017.10.033.
- Zlowodzki M, Chan S, Bhandari M, Kalliainen L, Schubert W. Anterior transposition compared with simple decompression for treatment of cubital tunnel syndrome: a meta-analysis of randomized, controlled trials. J Bone Joint Surg Am. 2007;89(12):2591-2598. doi:10.2106/JBJS.G.00183.
- Zhang D, Earp BE, Blazar P. Rates of complications and secondary surgeries after in situ cubital tunnel release compared with ulnar nerve transposition: a retrospective review. J Hand Surg Am. 2017;42(4):294.e1-294.e5. doi:10.1016/j.jhsa.2017.01.020.
- Mitchell J, Dunn JC, Kusnezov N, et al. The effect of operative technique on ulnar nerve strain following surgery for cubital tunnel syndrome. Hand (NY). 2015;10(4):707-711. doi:10.1007/s11552-015-9770-y.
- Gaspar MP, Kane PM, Putthiwara D, Jacoby SM, Osterman AL. Predicting revision following in situ ulnar nerve decompression for patients with idiopathic cubital tunnel syndrome. J Hand Surg Am. 2016;41(3):427-435. doi:10.1016/j.jhsa.2015.12.012.
- Krogue JD, Aleem AW, Osei DA, Goldfarb CA, Calfee RP. Predictors of surgical revision after in situ decompression of the ulnar nerve. J Shoulder Elbow Surg. 2015;24(4):634-639. doi:10.1016/j.jse.2014.12.015.
- Liu CH, Wu SQ, Ke XB, et al. Subcutaneous versus submuscular anterior transposition of the ulnar nerve for cubital tunnel syndrome: a systematic review and meta-analysis of randomized controlled trials and observational studies. Medicine (Baltimore). 2015;94(29):e1207. doi:10.1097/MD.0000000000001207.
- Bacle G, Marteau E, Freslon M, et al. Cubital tunnel syndrome: comparative results of a multicenter study of 4 surgical techniques with a mean follow-up of 92 months. Orthop Traumatol Surg Res. 2014;100(4)(suppl):S205-S208. doi:10.1016/j.otsr.2014.03.009.
- Zhou Y, Feng F, Qu X, et al. [Effectiveness comparison between two different methods of anterior transposition of the ulnar nerve in treatment of cubital tunnel syndrome]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2012;26(4):429-432. http://open.oriprobe.com/articles/29148370/EFFECTIVENESS_COMPARISON_BETWEEN_TWO_DIFFERENT_MET.htm.
Cite this article
Kalbian I, Ilyas AM. Ulnar nerve transposition (cadaver). J Med Insight. 2023;2023(206.5). doi:10.24296/jomi/206.5.
Table of Contents
- Excise Intermuscular Septum
- a. Close Cubital Tunnel
My name is Asif Ilyas. I'm a professor of orthopedic surgery and the program director of hand surgery at the Rothman Institute in Philadelphia at the Thomas Jefferson University. Today, we'll be talking about ulnar nerve transposition. Now ulnar nerve transposition is used to manage symptomatic cubital tunnel syndrome - also known as ulnar neuropathy of the elbow. That's when the ulnar nerve is under compression as it traverses the cubital tunnel behind the medial epicondyle at the level of the elbow. There's two broad ways to manage cubital tunnel syndrome. One is with a cubi- an in situ cubital tunnel release, and the other is with an ulnar nerve transposition. In this surgical video, we'll be looking at ulnar nerve transposition. A transposition can be performed in a few ways, including subcutaneous, intramuscular, and submuscular. I'll be demonstrating both the subcutaneous as well as the submuscular technique. As we go through the procedure, I'll show you some tips and tricks and hazards to avoid. We'll also discuss postoperative management and rehab.
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 two 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 an ulnar nerve transposition, you bring the elbow straight. You'll feel the epicondyle here. The tendency is to bring the incision anterior to the epicondyle, but recognize that you'll be away from your - 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, my incision will go anywhere from 6 to 8 cm distally - and similarly, about 6 to 10 cm, proximally. 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.
We do a long, longitudinal incision as marked out. Again, notice how the incision is fairly posterior, intentionally, to allow for easier exposure of the nerve as well as to decrease the odds of injuring or having to expose branches of the medial antebrachial cutaneous nerve.
And we'll start proximal. Tissue is easier to manage and more viab- and, safer. Cauterize vessels as you go in. I do this procedure under - with the patient asleep - and with a sterile tourniquet. The nerve is readily found proximal to the medial epicondyle, like so.
It's mobilized and released. What you're releasing is the arcade that envelops it proximally. There's vessels that travel with the nerve, and you try to maintain as many of them as - as you can. I'm never grabbing the nerve; I just push the nerve. That's what I'm doing right now. Then I'll switch to using either a Penrose drain or an equivalent drain to help kind of control the nerve. So here's my nerve. I'm going to expose distally next. Okay, I'll try to use some retractors if possible. Let's see how they do. So much bigger exposure than a cubital tunnel release. Again, this is a cadaver, so I'm cutting through some of these structures. But, you want to absolutely make sure they're not a nerve or a vessel. If they're a nerve, and you - you cut it by accident, you want to cauterize it, so as to not cause any painful neuromas. And if it's a vessel, you similarly want to cauterize it. So the nerve is fairly well mobilized, proximally. So I'm going to take that nerve release, distally, and you'll see it start to get tethered within the medial epicondyle. We want to mobilize that. The first branch we'll come across is the articular branch to the joint. And that you can readily cauterize. And the first, most important branch you'll get to are the motor branches to FCU. So we're traversing the cubital tunnel right here. There's adventitial tissue that holds it together. And here you'll see the fascia between the two heads of FCU covering the nerve. So I will release that fascia in line with the nerve, like so. But I want you to appreciate that there is also a deep investing fascia as well that can also put some compression on the nerve, and you just spread through it. So, once mobilized, kind of gently pull away. As we do this, those first branches will become evident. Right here is probably the first motor branch of FCU - right there. Now the question often comes up, what do you do with them? Well if you can maintain them, that's the optimal thing to do. If you can't, then it's reasonable to take the first or second branch and cauterize it. The ulnar nerve innervates the FCU the entire length of the arm, so if you take a branch or two, it will not result in any meaningful, denervation of the muscle - but avoid them if you can. Now you can see how loose the nerve is altogether.
So we want to transpose this anteriorly. So let's look at this now. So now that the nerve is released, we can transpose this in one of two ways; we can transpose this in a subcutaneous or a submuscular fashion, and I will demonstrate both.
Either way, irrespective of which transposition you elect to do, the main structure you need to confirm is decompressed - or removed rather - is the intermuscular septum. The intermuscular septum is often considered a constricting element to the ulnar nerve, but frankly it's more of a constricting structure to the ulnar nerve post-decompression. And I'll show you what I mean by that. So, here we go. So here is the intermuscular septum right here, and I'll expose it a little better for you so you can see it. It's this structure, right here, it comes off of the epicondyle, and it's quite palpable. And post-transposition, it can readily cause compression on the nerve, like so. So, it should be removed. So you can do this sharply, or you can do it with cautery. There are some bleeders back there, so cautery is a reasonable way to do this, but we'll use a knife here. You take it right off of the medial epicondyle. Again, there's a lot of bleeding structures back here. So, I tend to cauterize very generously in this region. Again, with a cadaver limb, we don't have that sense of the bleeding that can occur. Once I'm exposed enough, I just excise a centimeter segment of that intermuscular septum. So now, what you'll notice, epicondyle's here, and there's a bare, supracondylar ridge, like so. So then when the nerve is transposed, it sits over that ridge without any kind of external structures bothering it.
So let's transpose this and see how it looks. So if we transpose this anteriorly in a subcutaneous fashion, we see we're being tethered by this first branch of the ulnar nerve. So we have to make a decision if we want to keep that or not. Like I mentioned, there are many branches of the ulnar nerve to the FCU. So I'll often cauterize that first base. So here I'll just cut it. I'll cauterize it, and that really helps to mobilize this nerve even further. Once you transpose this anteriorly, the nerve's actually in more tension and extension than in flexion, which is the opposite of normal. So you can see how it drapes over top. It can be under some tension. This patient's very thin, so you notice there's very little tension on the nerve. But you'll also notice when I flex how the nerve crimps up and has absolutely not tension on it. And most of us spend most of our time with some amount of elbow flexion. So you'll notice how there's no tension on the nerve once it's in this position. Now how do we stabilize this? Well there's a few ways to stabilize this nerve, and I'll show you the subcutaneous technique first, and then the submuscular technique with a z-plasty.
So when doing a subcutaneous transposition, the nerve moved anteriorly, the intermuscular septum taken down, I recommend two things to stabilize the nerve anteriorly. The first thing is to actually close the cubital tunnel so that you prevent any inadvertent re-subluxation of the nerve back behind the epicondyle, because if it does, it will be trapped there. So what you do is you take your posterior tissues, mostly some triceps extension right here, and you just - you come across your epicondyle, and you just close that interval. So typically, two sutures are more than sufficient. I use two figure-of-eights to close the interval down. And again, this is so that the nerve does not inadvertently re-sublux into the cubital tunnel. So that's the first thing. So once that's done, the second thing you want to do to stabilize the nerve, anteriorly, is you want to place some kind of fascial sling to hold it in place. So once the cubital tunnel has been closed with some of the fascia of the triceps, you need a fascial sling to hold the nerve anteriorly. So I just take a little bit of the posterior aspect of the fascia of FCU and come across like so. Leave it attached to its origin on the epicondyle and then tease it back. And then this then is subsequently repaired. Repaired to here. Looking for a second pickup - here we go. So using a 2-0 Vicryl or equivalent, repair like so. And what that does with this repaired, it prevents the nerve from translating posterior - it acts as a - a post or a bolster to prevent it from slipping back, as such.
Alternatively, a submuscular transposition can be done. And I will actually translate the nerve posteriorly, temporarily. And to do this with a z-plasty, the orientation you want to have is basically like so. Okay? So we also already did some of it, like so. And then we come across. It's a little short, but that's okay. And we come across like this to complete the rest of it. Now how deep you take this is what defines whether this is an intramuscular or a submuscular. Obviously, this requires significant dissection and splitting of the FCU muscle belly. This is not my preferred way to do transposition, but it is a very effective way to do it. And I'll use this technique in revision cases or cases where I need to bury the nerve a bit - maybe a complaint of neuritis or what have you, a thin patient - and that way it allows me to make the nerve less palpable. And then these two ends - I'll show you the orientation again. They start like this, and then once we're done, it's like this. So let's move that nerve into this space here. Actually, I'm going to release some of this fascia here first. I have to stay close the epicondyle as the medial - median nerve is not far from here. So I don't want to wander too far away. I'm just staying on the supracondylar ridge. The nerve then just moves over to here, anteriorly. We have this branch here. This leaflet here and this leaflet here is then repaired end-to-end, like so. One or two figure-of-eight sutures will do the trick. You have to be mindful not to cause a new site of constriction of the nerve. I'll just do one for the sake of demonstration, but obviously, you can do more as needed. Like so. Once done, you'll now have a submuscular - or intramuscular - transposition of the ulnar nerve. And let's take a look at that. So here's our bridge. It's been lengthened with a z-plasty. The nerve is below. You want to make sure you absolutely have plenty of room for the nerve. You want to check your nerve deep. Make sure it's satisfied and not tight. Here you'll find a little bit of residual tension of that deep investing fascia that I had mentioned. I'll release that a little bit further. So here's that deep investing fascia. The nerve is deep to me. There's that fascial layer. I'll just release that a little bit further. Once released, you'll notice the nerve is very loose. I can easily pull it in either direction with no tension on it. Like so.
I then again take the nerve through an active range of motion to confirm that there is no tension on it. Again, no tension.
At this point, I typically drop the tourniquet as there's typically quite a lot of bleeding because of all of the cutting of the FCU - I'm sorry, the flexor pronator mass musculature. So I'll cauterize that until satisfied. I do no more additional deep closure. I just close the skin with 3-0 Vicryl or an equivalent, and a running 4-0 Monocryl, and then a glue for the skin, or a nylon for the skin.