Does saddle area numbness resolve over time? My understanding is that numbness and muscle weakness are both caused by nerve compression. I had surgery to decompress the nerves and my muscle weakness is improving, but the numbness has not changed. If both symptoms are caused by nerve compression and the surgery decompressed the nerve, why is the muscle tone returning, but not the sensation? Thanks for your time!

Doctor Joshua’s Answer:

This has to do with spinal nerve anatomy, and more specifically the location of the nerve cell bodies. The nerve cells that move the muscles are called motor neurons. The cell body of the motor neuron is inside the spinal cord, and from there on the nerve contains only the long nerve fiber, called the axon, so in the event of nerve compression, only the axon is damaged. The axon is surrounded by a sheath, and it regrows using that sheath as a guide.

Sensation, on the other hand, is handled by the sensory nerves. The sensory nerve cells are called afferent neurons. The cell body of the afferent neuron is located outside the spinal cord, in what is called the dorsal root ganglion. The dorsal root ganglion is located so that nerve compression may damage the nerve cell the ganglion, or the ganglion itself, which means that either the neuron is damaged above the cell body, or the cell body itself is damaged. Whenever this happens, the healing is much slower than when the damage happens at the level of the axon, or below the cell body.

I hope that made sense! It’s a pretty complicated matter, not easy to explain very clearly, but the point is that there is an anatomical reason for the difference in recovery time you are experiencing. Whether the sensation will recover fully or not, only time will tell, but patience is definitely needed - nerves heal very slowly.

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