Name:
RPNI and TMR: Surgical Techniques
Description:
RPNI and TMR: Surgical Techniques
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Duration:
T00H11M51S
Embed URL:
https://stream.cadmore.media/player/b5858b85-fb2f-4306-88ad-2fd48e75aa89
Content URL:
https://cadmoreoriginalmedia.blob.core.windows.net/b5858b85-fb2f-4306-88ad-2fd48e75aa89/v-005709.mp4?sv=2019-02-02&sr=c&sig=UQE1iE%2BP%2BB5C5PIplBY%2By9Kk27ZxTOL3s4hPrNZLlMc%3D&st=2024-11-24T00%3A07%3A22Z&se=2024-11-24T02%3A12%3A22Z&sp=r
Upload Date:
2024-05-31T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
JULIA MASTRACCI: The purpose of this video is to demonstrate the surgical techniques for regenerative peripheral nerve interface and targeted muscle reinnervation. The authors have the following disclosures. In the United states, 1 to 2 million people are living with limb amputations, with approximately 180,000 amputations performed annually. Neuromas are a known complication of amputation and can be painful, limit prosthetic use and result in a lower quality of life.
JULIA MASTRACCI: Regenerative peripheral nerve interface or RPNI is a technique where a free nerve end is implanted into a denervated free muscle graft. This provides regenerating nerve with a target to form new neuromuscular junctions. RPNI has been shown to decrease residual stump pain, decrease phantom limb pain and increase prosthesis use. In a study comparing prophylactic RPNI at the time of upper or lower extremity amputation versus amputation alone, the prophylactic RPNI group experienced significantly less symptomatic neuromas and less phantom limb pain.
JULIA MASTRACCI: A separate study examined prophylactic RPNI in patients with insulin dependent diabetes at the time of a lower extremity amputation for a soft tissue infection. The prophylactic RPNI group experienced significantly less limb pain and more frequent prosthesis use compared to the control group. Targeted muscle reinnervation or TMR is a technique where a nerve is transferred to a new muscle target.
JULIA MASTRACCI: This transfer eliminates wasted neural input to muscles, which is thought to contribute to the development of painful neuromas. Reinnervation of the new muscles may act as a biologic amplifier of motor commands allowing for myoelectric prosthesis control. TMR has been shown to prevent the formation of painful neuromas. In two cohort studies, patients who had TMR performed at the time of limb amputation experienced significantly less phantom limb pain, less severe and less frequent stump pain compared to those who underwent amputation alone.
JULIA MASTRACCI: TMR has also been shown to treat existing neuroma pain. A prospective randomized controlled trial demonstrated that patients with a prior amputation who were experiencing chronic pain had a significant change in phantom limb pain after TMR compared to patients who underwent neuroma excision. It has also been demonstrated that TMR improves myoelectric prosthesis control. TMR and RPNI can be performed in both an acute or a delayed fashion.
JULIA MASTRACCI: Indications for TMR and RPNI include stump pain, phantom limb pain and desire for improved myoelectric prosthesis use. Potential contraindications include open wounds or infection, active radiation therapy and patients with cognitive impairments. Moving on to a case example. D.H. is a 22-year-old male disposed right upper extremity metacarpal amputation due to a firework injury.
JULIA MASTRACCI: He develops significant phantom pains and hypersensitive neuromas. The surgical plan for this patient was revision amputation to the transradial level, RPNI of the ulnar and radial sensory nerves to treat his painful neuromas and TMR of the median nerve into a pedicled pronator quadratus muscle flap to allow for use of a myoelectric prosthesis.
JULIA MASTRACCI: Of note, an alternative surgical plan for use in distal forearm amputations is as follows. RPNI of the radial sensory nerve, TMR of the median nerve in the pedicled pronator quadratus and TMR of the distal median nerve into flexor pollicis longus. The selective muscles are non prescriptive. Any combination of TMR and/or RPNI can be performed and more proximal targets can be utilized as well.
JULIA MASTRACCI: However, we favor using distal targets when performing the transradial amputation so that the procedure can be done exclusively through a single distal incision. We thereby avoid additional proximal incisions and insections and in our experience, eliminate potential pain at the proximal forearm where the prosthesis makes contact. The surgical site was marked and a safety timeout was performed.
JULIA MASTRACCI: This is the patient's right upper extremity in a supinated position with the radial aspect of the forearm closest to the viewer. Esmark exsanguination was performed and the tourniquet was inflated. Begin with a fish mouth incision. Our goal amputation site was seven centimeters proximal to the tip of the radial styloid to allow for optimal prosthesis fitting.
JULIA MASTRACCI: Identify the neuralised, the radial sensory nerve. Tie off the radial artery. Identify and neurolyse the median nerve and the palmar cutaneous branch of the median nerve.
JULIA MASTRACCI: Tie off the ulnar artery. Identify and neurolyse the ulna nerve.
JULIA MASTRACCI: Then transect the flexor tendons at the musculotendinous junctions. Carefully release the pronator quadratus off of the distal radius and the distal ulna.
JULIA MASTRACCI: Then perform the radius and ulna osteotomies using a retractor to serve as a backstop to protect the soft tissues. Again, our ideal amputation site is seven centimeters proximal to the tip of the radial styloid to allow for optimal prosthetic fit. Begin the muscle graft harvest for the RPNI portion of the procedure. We harvested two 3 by 1 centimeter areas of muscle from the extensor carpi radialis longus and brevis.
JULIA MASTRACCI: Store the muscle in a moist sponge. For RPNI number one, sharply transect the ulnar nerve, then using 6-0 nylon, suture the ulnar nerve into the first muscle graft. The goal is to directly repair the epineurium ulnar nerve into the muscle, then subsequently wrap the muscle around the nerve to prevent axon escape.
JULIA MASTRACCI:
JULIA MASTRACCI: Secure the first RPNI into its forearm position using 2-0 vicryl. For RPNI number 2, sharply transect the radial sensory nerve.
JULIA MASTRACCI: Then, repeat the prior demonstrated suturing technique used for RPNI number 1. Secure the second RPNI into the forearm's soft tissues. Moving on to the TMR portion of the procedure. Identify and neutralize the AIN as it enters the pronator quadratus.
JULIA MASTRACCI: Sharply transect the median nerve, then, suture the median nerve donor, into the AIN recipient using 8-0 nylon.
JULIA MASTRACCI: Repair the median nerve and AIN epineurium directly into the pronator quadratus to prevent axon escape using 6-0 nylon suture.
JULIA MASTRACCI: Suture the pedicled pronator quadratus muscle into position over the end of the residual radius and ulna.
JULIA MASTRACCI: Finally, trim the excess tendons, irrigate and close. Our patient is now 18 months post operative and he is able to wear his myoelectric prosthesis for over eight hours per day. He has no pain in the residual limb and has phantom awareness of the distal forearm and hand, but does not have any phantom pain.
JULIA MASTRACCI:
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