Do you think if I have surgery to cut the nerves to my wrist, I'll lose the sense of where my hands are? I am a musician in need of pain relief but not at the expense of not feeling my wrists and hands.
Wrist pain can be very chronic and very debilitating sometimes. When conservative (nonoperative) care isn't successful in changing the clinical picture, then wrist denervation may be advised. This procedure has been done many many times with reliable results. Pain relief without loss of motion is the goal.
Cutting the sensory nerves that relay pain messages to the brain (not the motor nerves that control movement) is helpful in up to 90 per cent of all cases reported. However, your concern about feeling the position of the joints (something called proprioception) and sense of movement of the wrist and hands (called kinesthesia) is important.
A recent study at Mayo Clinic in Rochester, Minnesota took a look at this very phenomenon. They tested and measured the potential effect of denervating two nerves in the wrist on active and passive wrist motion. In the real surgical procedure, the nerves causing chronic pain would be cut. The purpose of the procedure is to eliminate wrist pain. This may be what you are referring to.
In this study, the subjects' wrists were injected with a specific solution. The idea was to mimic denervation but without actually killing or permanently altering the sensory nerves responsible for transmitting information.
Two groups of normal adults between the ages of 20 and 54 were included in the study. A total of 80 people participated. One group received a real anesthetic to block the anterior and posterior interosseous nerves. The second (control) group received an injection of a saline (salt) solution to the same nerves.
After the injection, they measured the accuracy (or alternately, the error) in active and passive wrist motion. They did this by placing the wrist in one position and asking the patients to (as accurately as possible) reposition the joint to match the first position. Positions used included 10, 20, and 30-degrees of both wrist flexion and extension. The difference between the actual position and the place the volunteer moved the wrist to was calculated.
Two trials were completed (performed randomly) in each position with a rest of 30 seconds between. The wrist was fully relaxed between trials. They found there were no differences between the groups in ability to reproduce the test position. This indicates that even with nerve anesthetization (mimicking denervation), it is possible to accurately detect active and passive wrist motion. In other words, kinesthetic sense was not impaired or altered by blocking the nerves.
The authors suggest these results infer that effective partial denervation procedures are safe. The accessory nerves are still able to transmit important information about propriocetpion even with the sensory nerves blocked.