Wrist extensor recovery in traumatic quadriplegia.

Wrist extensor recovery is of major functional significance in many quadriplegic patients. In this retrospective study, we investigated a method for prognosticating wrist extensor recovery and the underlying mechanisms for improvement in strength. Thirty-five quadriplegic patients at the C4, C5, and C6 neurologic levels, admitted over a four-year period, were examined at one week, two months, and eight months postinjury for biceps and wrist extensor strength. Initial biceps strength was compared to final wrist extensor strength. All 16 C5 patients whose initial biceps strength was grade 3 showed wrist extensor improvement to grade 3; only three of 16 C4 patients showed the same improvement. We concluded that initial biceps strength is a reliable indicator of wrist extensor recovery, and most, if not all, C5 neurologic patients will gain one full motor level. This improvement may be due to compensatory factors, such as overwork hypertrophy and peripheral sprouting of nerves within the muscle, rather than to recovery of a root level.