Name:
10.3171/2022.10.FOCVID2293
Description:
10.3171/2022.10.FOCVID2293
Thumbnail URL:
https://cadmoremediastorage.blob.core.windows.net/a849187d-034d-42a0-8e80-f220ed12bb41/videoscrubberimages/Scrubber_478.jpg
Duration:
T00H09M12S
Embed URL:
https://stream.cadmore.media/player/a849187d-034d-42a0-8e80-f220ed12bb41
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/a849187d-034d-42a0-8e80-f220ed12bb41/12. 22-93.mp4?sv=2019-02-02&sr=c&sig=z6tcTyG6sZKUOtPB9FbwayCvsZVyalEGDludNs6DSOQ%3D&st=2024-11-29T14%3A33%3A55Z&se=2024-11-29T16%3A38%3A55Z&sp=r
Upload Date:
2022-11-18T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
[MUSIC PLAYING]
SPEAKER: Targeted muscle reinnervation in above-knee amputation: a surgical technique. In the United States, there's an estimated 185,000 people who undergo amputation of an upper or lower limb each year. In 85% of cases, it results in residual limb pain. Targeted muscle reinnervation is a technique that's been shown to inhibit symptomatic neuroma formation.
SPEAKER: And in this case, we will demonstrate our surgical technique for performing TMR at the time of an above-knee amputation. So first, we identify the ASIS and the medial knee. Running in between that is the sartorius muscle. And underneath that is the saphenous nerve. So just medial to the sartorius muscle, we make our incision. And once that incision is made, skin and soft tissue are divided until we're able to expose and identify the great saphenous vein.
SPEAKER: And once we expose that great saphenous vein, which you can see here, it's retracted medially so that we can incise the sartorius fascia. And once that's done, you can see through this little window here a peek at a branch of the saphenous nerve. That sartorius fascia is continued to be incised superiorly.
SPEAKER: And here you can get a clear picture of that saphenous nerve branch. The sartorius muscle is freed both medially and laterally. And here you can see the superficial femoral artery. Running lateral to that are two nerves. And we want to identify, are these nerves motor, or are they sensory?
SPEAKER: So we take our nerve stimulator. And upon stimulating the medial nerve, nothing happens, whereas when we stimulate the lateral nerve, we get a motor contraction. Now it's time to cut the nerves. And it's important that when you're cutting the sensory nerve, you make a distal cut, whereas when you're cutting the motor nerve, you make a cut more proximally.
SPEAKER: And the reason this is important is because when you bring these two nerves together, you want them to be under minimal tension. Using a 6-0 Prolene, we throw a few interrupteds into the epineurium of the nerves to bring them together. And here, the surgeon shows us the result. It is a sensory saphenous branch and a motor sartorius branch under a tension-free coaptation.
SPEAKER: More proximally, we once again use our nerve stimulator to identify a sensory saphenous branch over the superficial aspect of the sartorius muscle as well as an adjacent motor branch. There was an additional nearby motor branch entering the sartorius more proximally, and that branch is cut.
SPEAKER: Then the sensory branch is cut distally to provide maximal length. Then the first motor branch we identified is cut proximally. The next step is to bring all these nerves together. So we'll have one sensory branch coapted to two motor branches. We coapt the two motor branches to mitigate the size mismatch between the large sensory nerve and smaller motor nerves and to create a fertile wound bed of denervated muscle for the sensory nerves to have somewhere to go and something to do.
SPEAKER: So to summarize, we have a sensory saphenous nerve branch plugged into two motor branches to the sartorius muscle. Finally, we find additional sensory branches of the saphenous nerve and adjacent motor nerves more distally using our nerve stimulator. Once again, the sensory nerve is cut distally, and the motor nerve is cut proximally. And the two are coapted without tension using two epineurial sutures.
SPEAKER: We typically place at least two epineurial sutures at the nerve coaptation, both for security and for good approximation of the two nerve ends. We also occasionally apply Tisseel to reinforce the coaptation. So in summary, we have identified three sensory branches of the saphenous nerve and have three sites of nerve coaptation: one distally, one in the midportion, and one proximally, with a double motor nerve coaptation.
SPEAKER: Our TMR incision is closed in layers with interrupted 3-0 Vicryl and 4-0 Monocryl sutures. A drain is placed at each surgical site. And the transfemoral amputation site is closed with interrupted 3-0 Vicryl sutures and staples. For the second portion of the case, in a transfemoral amputee, the patient is placed in prone position to access the posterior thigh. And a 12-cm incision is made in the midportion of the thigh, starting at the gluteal skin crease.
SPEAKER: And skin and soft tissue are divided until we're able to identify the posterior femoral cutaneous nerve of the thigh. Once identified, the nerve is mobilized distally. And we then divide and retract the nerve for TMR later. We identify the sciatic nerve by palpating between the hamstring muscles, and dissect it as far distally as possible through the incision.
SPEAKER: With gentle retraction, we deliver the nerve through our incision. And since it's already been transfected distally as a part of the amputation, you can see the division into the tibial and peroneal components here. Using our nerve stimulator, we identify four distinct motor nerves.
SPEAKER: These included motor branches to the semitendinosus and semimembranosus, a larger 3-mm branch to the biceps femoris, as well as a smaller branch to the biceps femoris. Each motor nerve is transected proximally for maximal length. We then split the sciatic nerve into its tibial and peroneal components.
SPEAKER: The tibial component is cut, and its distal remnant is discarded. Here we see the proximal cut end of the tibial nerve, which will be coapted to two motor nerves, to the semitendinosus and semimembranosus. Note how, proximally, the motor nerves have been identified in the posterior thigh.
SPEAKER: This is important since it ensures a large caliber of the motor nerve before it has arborized into the muscle more distally and improves the size mismatch between the large tibial and peroneal nerves. Transecting the motor nerves more proximally also effectively denervates the posterior thigh musculature, resulting in more target receptors for the sensory nerves to grow into. We then cut the peroneal component of the sciatic nerve.
SPEAKER: And here you see that large motor branch of the biceps femoris, which is going to be coapted to that proximal cut end of the peroneal nerve. And finally, we bring in our posterior femoral cutaneous nerve back into the field, which, if you recall, was cut and retracted earlier. And that nerve is going to be sewn directly into the biceps femoris muscle, where the small motor branch enters.
SPEAKER: And this is mitigating some of the size mismatch and ensuring the sensory nerve is adjacent to the motor nerve and denervated muscle fibers. So to summarize, we have three sites of neural coaptations: the posterior femoral cutaneous nerve to the biceps femoris; the tibial component of the sciatic nerve to two motor branches, the semitendinosus and semimembranosus; and the peroneal component of the sciatic nerve to the biceps femoris.
SPEAKER: You can pause the video here to see a summary of the coaptations on the anterior and posterior sides. A drain is placed and the incision is closed in layers with 3-0 Vicyrl and 4-0 Monocryl suture. Following TMR at the time of amputation, patients are instructed to remain non-weight-bearing to the amputated extremity for 6 to 8 weeks.
SPEAKER: Prosthetic usage is avoided for at least 1 month postoperatively, though early shrinker wear is encouraged as soon as drains are removed. At this patient's most recent follow-up visit 3 months later, she reports no stomach pain and no phantom limb pain.
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