About RPNI Surgery
- Regenerative peripheral nerve interface (RPNI) surgery is a less invasive procedure than targeted muscle reinnervation (TMR). Therefore, it is sometimes called a “mini-TMR”.
- RPNI is not as effective as TMR for the relief of neuroma or phantom limb pain. It is usually used for patients who have neuromas where there are no suitable muscle targets (such as a fingertip) or after a TMR procedure has already been performed.
In an RPNI procedure, the neuroma on the end of your nerve is removed. Your surgeon will then take small pieces of muscle from another part of your body, such as your thigh. They will wrap this piece of muscle around the end of your nerve, and this encourages the nerve fibres to connect with the muscle (i.e. “reinnervate” the muscle). When it works, RPNI has the same effect as a full TMR procedure. However, studies suggest it only works completely in about 50% of neuroma cases.
I underwent surgery to fuse a joint in my index finger a few years ago. Unfortunately, the surgery didn’t quite go as planned. I developed a bad wound infection, and this meant that I had to be readmitted to hospital for intravenous antibiotics and removal of the metalwork used to fuse the joint. Eventually, the bones in my finger fused but I was left with a chronically painful finger. Even the slightest touch would trigger off waves of pins and needles, which travelled up my finger.
Eventually, I just stopped using the finger altogether when trying to carry out my daily tasks. I also had to start taking regular pain killing medications such as pregabalin and tramadol. The drugs made me sleepy and forgetful. The tramadol made me constipated.
Although I was able to accept this, it wasn’t nice, and I kept asking my original surgeon if there was something else that could be done to help. Finally, she referred me to the Relimb team for help.
After examining my finger, they diagnosed a neuroma, which was the result of a nerve being cut during the original surgery to fuse my joint. They recommended an RPNI procedure since this would stop the neuroma from being so sensitive.
The surgery was carried out under local anaesthetic. I was very apprehensive about the surgery. What if it didn’t work? What if the surgery was painful? What if it went wrong like the first operation?
Thankfully, I needn’t have worried. Within a few days, it was clear that the neuroma pain had gone and it never came back. It took about 6 months for the hypersensitivity of my finger to settle but that was OK too. By the end of 12 months, I had stopped taking the pregabalin and tramadol and I am now able to use the finger for my daily tasks. I still have a sensitive finger in cold weather, but I can live with that.
I am so grateful for the improvements to my symptoms that the team at Relimb have achieved for me.
Aftercare and Pain Control FAQs
Do I need to stay in overnight for RPNI?
If you choose to undergo RPNI only (i.e. not in combination with osseointegration), you will generally be able to go home on the same day as your surgery. Some patients with more complex needs, such as after a through-shoulder amputation (who are likely to have had a TMR procedure as well), may need to stay overnight for support you with pain control..
What kind of medications should I take to manage my pain after the procedure?
We advise you to continue taking your normal pain medications.
The pain after this surgery is minimal and easily controlled with standard pain medication for a few days, although we may also advise you to increase your anti-neuroma or phantom limb pain medications in line with your symptoms.
Can I shower after surgery?
You may wash and shower with running water immediately after surgery.
What kind of wounds will I have to care for?
After RPNI surgery, your primary incision will be closed (typically) with absorbable sutures, which do not need to be removed.
There will be an additional incision over your thigh (or forearm) where we harvested your muscle graft for the RPNI.
How long until I can start using my prosthesis again?
You should avoid any heavy use of your limb for 2-3 weeks. You should not use your prosthesis until the wound has healed (3 – 6 weeks – longer for lower limb RPNI), and any associated soft-tissue swelling has resolved.
What kind of rehabilitation do I need?
You do not need to have any specific rehabilitation after an RPNI procedure for relief of pain.