Two parts to todays update before the nerve block is removed-A quick update on the last 36 hours then the details I promised on the sciatic nerve.

The last 36 hours

Carson's pain has become one of the hardest parts of this entire experience. No, I won’t descend into pain as a philosophical topic…today.

Carson has three different pain problems in the same leg. Orthopedic pain from a destroyed knee and a femur that was surgically cut and shortened. Soft tissue pain from extraordinary damage to muscle, tendons, ligaments and skin. And nerve pain, which is an entirely different animal.

The team is working hard, but there is both a lot of different opinions and no obvious playbook for a young man with this collection of injuries. Right now, Carson feels somewhat like himself maybe 15-30% of the day. Yesterday and the night before, he had a lot of pain, but also visits from two groups of friends with a lot of smiling and laughing. The rest of the time he oscillates between sleeping it off, managing it and sitting in the excruciating moments.  Some visitors get that experience.

That kind of pain has you find resilience, until it doesn’t. We hope it shifts in the next couple days. 

If they can't get the pain under control, moving him back to the ICU is a possibility, simply because there are medications and monitoring available there that the trauma floor doesn't have. This will eventually get better. 

Right now, he’s sitting in front of me having eaten a good breakfast and begun his 80-hour journey of watching all the marvel movies…even the bad ones. 

Now that’s commitment. 

THE SCIATIC NERVE

A disclaimer before I pretend to teach neurobiology. I'm spending a lot of time reading, researching, analyzing, talking to physicians, trying to understand peripheral nerves well enough to advocate for Carson. That does not make me a nerve surgeon. Somewhere a real expert may read this and roll their eyes at my attempt at accuracy.

I also said I'd give you the technical details as I understand them.  Some of this may sound cold or curiously obtuse coming from his dad since the clinical realities are sobering. Understanding these realities has been heartbreaking, created a sense of desperation and despair and yet, has fortified my and Barrie’s resolve.  It’s simply time to get to work to figure this shit out.  The odds for a full recovery are long, but that's the makings of a great damn story.  Watch Doctor Strange…Kamar-Taj here we come. 

The Nerves-The first thing I misunderstood was what it means to reattach a nerve. I assumed you sew it back together and pending the quality of the surgical procedure, “things” start to come online.

Not even close. When a nerve is severed, the fibers below lose their connection to the cells they came from and degenerate. That's called Wallerian degeneration, and nothing stops it (Insert potential expert eye-roll).  So even though Carson's sciatic nerve has been reconnected, those fibers don't wake back up. They have to be replaced by new growth.

That's why he can't feel his left foot, wiggle his toes, move his ankle, or control the muscles below his knee. The sciatic nerve provides essentially all the motor control and much of the sensation. It also powers most of the hamstring, which is what bends the knee.

So what did they actually reconnect during surgery? Think of a nerve like a massive bundled cable. Inside the “housing” are thousands of individual fibers, called axons, wrapped in layers of connective tissue. Surgeons can't sew thousands of microscopic axons together. They align the severed ends of the cable and secure the tissue around it, creating the best possible pathway for new axons growing down to their destination, from above.

TIME IS THE ENEMY

Nerves regenerate painfully slowly. Roughly an inch a month. Carson's injury is very high in the leg, near the top of the hamstring, so the new fibers have a long way to travel to reach a destination that creates both feeling and motor function.

I'll set aside the explanation of Schwann cells, motor endplates and other technical terms that don't really matter here and are above my paygrade. The summary is this: over time, the body loses its ability to receive nerve regrowth. The further from the injury site, the less likely function is restored. Insert mystical movie reference, miraculous healing, the quantum nature of reality, divine intervention and sheer, undetermined will.

There are two destinations for Carson's sciatic nerve. One is around the knee, which restores his ability to move his lower leg. The other is down into the ankle and foot, which restores ankle movement and toe function.

The race isn't whether the nerve grows. It will most likely grow. It's whether the leg and foot are still ready to receive it when it arrives. Muscle without nerve input atrophies fast, with one widely cited estimate putting the loss at 60 to 80% of volume by around four months. And beyond simple atrophy, muscles lose their ability to receive stimulation from a nerve at all. That window appears to be about 12 months.

One inch per month. About 30 inches to reach the foot. Twelve months before the door closes.

Time is the enemy.

The knee should be reachable, provided it can be repaired, which remains an open question. The foot is the harder problem, and many people with this injury never regain foot function because the growth simply takes too long.

So, over the next 12 months we will learn whether motor function is returning to the knee. During that same window we will pursue newer and creative treatments that may keep the lower leg receptive to a nerve that hasn't arrived yet.

HOW CAN A NUMB LEG HURT THIS BADLY?

Touch Carson's foot and, other than the inside of his big toe, nothing registers. Yet he feels savage pain he perceives as coming from that same foot.

Normal sensation and neuropathic pain are not the same thing. After a severe nerve injury, injured sensory neurons generate abnormal electrical activity, at the injury itself, in the nerve cell bodies upstream, and through changes in the spinal cord and brain as the nervous system reacts to losing its normal input. The brain reads those signals as pain in a foot that isn't sending it any real information.

The foot has gone quiet. The nervous system hasn't.

That helps explain why enormous amounts of pain medication have done so little. Neuropathic pain responds incompletely to opioids because the biology is different from a broken bone or a surgical incision. Carson has all three stacked on top of each other, which is the puzzle his pain team is trying to solve.

SO WHAT DO WE DO?

We can't command Carson's nerve to regenerate. We can't guarantee an axon growing down his leg finds the right pathway, reaches the right muscle, and teaches that muscle to work again.

What we can do is create all possible conditions. Protect the repair. Preserve mobility. Protect muscle and joints while they wait. Use rehabilitation intelligently. Watch for signs of regeneration. Control the pain well enough that Carson can sleep, heal and do the work ahead.

And stay relentlessly curious about legitimate therapies that may improve regeneration, preserve muscle, or extend the critical time window. There's real research in electrical stimulation, rehabilitation strategy, hyperbaric treatment, nutrition, nerve transfers and biologics. Some has meaningful clinical evidence. Some is promising but early.

We have made a connection with arguably the OG of peripheral nerve research and surgery, Dr. Susan Mackinnon, who leads that work at Washington University in St. Louis. My shoulder surgeon knows her and as it turns out, Carson’s nerve surgeon here in Denver, Dr. Desai trained with her years ago and said, “She’s the best”.  She is reviewing Carson's case. We don't know if she'll take him. We don't know if they can help. But every stone gets turned over.

That kind of academic setting matters for a reason beyond reputation. Community hospitals do largely what is proven. Universities are willing to test and evolve new treatments. When the standard path has a hard ceiling, and for a nerve injury this high up it does, the place to go is where people are running the trials, testing the techniques that haven't reached practice yet, and willing to think about a case that doesn't fit the textbook. That's where the creative options live, and Carson needs creative.

So, there are two truths living beside each other right now. We have no idea how much function Carson will ultimately regain. And we are completely clear that our shared purpose has us exhausting every possible path to the greatest possible outcome.