[caption id="attachment_13658" align="alignleft" width="202" caption="Manning does his best to show his nerve"][/caption] Over the past several weeks, information has been bubbling - and is now a full-blown geyser - that Peyton's recovery hinges on the regeneration of nerves, either in his neck or upper arm. This post explores (lightly) the anatomy of nerve regeneration and what it implies about Manning's situation. For a nerve to have to regenerate, that would imply that the surgery Peyton had was not just to remove part of a bulging disc (which would have just impinged an otherwise-healthy nerve). It probably means that that disc had interfered with the nerve for a long enough period of time to have also damaged it. This assumption is reinforced by Peyton's assertion that he sought the advice of several specialists and was told that surgery was unavoidable. As for the anatomy... there are two primary components to nerves - the axon (which is like the central "wire" that conducts the signals) and the myelin (the sheath or cover around the wire). When only the myelin is damaged, a nerve can heal quickly (within weeks). When the axon is also damaged, however, it takes longer to heal.
Assuming there is still continuity of the axon (i.e., that it hasn't been severed, or split apart in the middle), it takes approximately 1 month to regenerate each inch of damaged nerve. If everyone could please get out their abacus... the fact that Manning had his surgery 4 months ago and that the impacted nerves have apparently not yet regenerated fully implies that there were... drop the 4... carry the 2... at least 4 full inches of nerve to repair. However, this is inconsistent with sports medicine expert Dr. Sheeraz Qureshi's expectation (from afar) that Manning could start physical therapy and strength training 4-5 weeks after the procedure. It is also inconsistent with Jim Irsay's confidence at the time that Manning would need only 8 weeks to recover - including rehab - and would be at training camp. Based on his comments, it appears that Qureshi assumed that there had been little to no nerve damage. And while Qureshi did not examine Manning personally, Irsay was also confident, implying that Dr. Richard Fessler (the neurosurgeon who did perform the procedure) gave him no information to feel otherwise. Yet here we sit, 4 months later, with Manning still on the Physically Unable to Perform list, a new (old) backup quarterback signed, and continued comments about the need for Manning's nerves to regenerate. A possibility that I hate to have to explore, but which we may have to soon, is that there was enough nerve damage that complete regeneration will not be possible, or that Manning's system - despite his long-standing status as a model of health - is simply incapable of doing so.