It’s been three months since my husband caught his arm in a piece of farm equipment and ripped a hole in his arm. Nothing was broken but the nerve near his elbow was chewed up pretty good. We are in a wait-and-see mode with treatment. Hand therapy for now. Maybe surgery later. But how long do we wait before we push the envelope and go for the more aggressive (surgical) treatment? I’m not as patient as my farmer boy.

Nerve injuries such as you describe can be very difficult to recover from. When a nerve is torn, crushed, or pinched, it takes about a month for an inch of that nerve to heal. If the injury is high up by the elbow, that same nerve goes all the way down to the hand. So sensation and muscle control in the hand and fingers may not return for months.

If too much time goes by, scar tissue and degeneration of the motor endplate (where the nerve meets the muscle) may prevent full recovery from occurring. The motor endplate is the highly-excitable region of muscle fiber responsible for the start of action potentials (firing signals) across the muscle’s surface, ultimately causing the muscle to contract. Without a nerve signal, the motor endplate remains silent. And over time, that silence translates into a breakdown of the endplate. If that happens, permanent silence occurs and loss of motor recovery.

Surgeons monitor patients carefully week-by-week and month-by-month for any signs of nerve regeneration and motor recovery. They use pinch and grip strength and sensory testing to measure change. A special test called Semmes-Weinstein monofilament exam measures the patient’s ability to feel two points of touch on the skin. If no change or improvement is seen, then special neurodiagnostic tests can be done.

They use the rule of 18 to gauge recovery and plan treatment. The rule of 18 says that motor recovery won’t happen past 18 inches from the nerve injury after 18 months have passed. This is because as we said earlier, nerves regenerate at the rate of about one inch per month. And motor endplates degenerate 18 months after nerve damage.

If by four months after the injury there has been no recovery or very little improvement, then testing is repeated and repeat neurodiagnostic tests are ordered. Surgery is often recommended at this point to explore what’s going on and either repair or reconstruct the damaged nerves, tendons, and muscles. So, at three months, you are probably still within the acceptable and recommended wait-and-see period of time. You should have some answers in the next four to six weeks. If not, ask the surgeon for a review of your husband’s case and be prepared to ask some questions based on the information here. Good luck!