Can you help me figure out the discrepancy between your notes & Campbell text on L3 & L4 lesions. I thought L3 lesions had quadricep grade 3 or better, but in your notes it says “weak knee extensors” for possible muscle function. I thought L4 lesion met or exceeded the criteria for L3 (ie. quadricep strength 3 or better), but in your notes it says “weak knee extensors” (in addition to having adequate medial knee flexors & ankle DF which are correct and in line with Campbell text). Thanks for your clarification.
L3 and L4 both innervate knee extensors, so you would expect a degree of quadriceps weakness if these are affected. Clinically, the “level of weakness” varies from person to person because “lesion levels” do not all act the same. There are some institutes that do not even provide lesion levels because of how much variability is seen from patient to patient. I think the overall take away message for L3 and L4 lesions is that the child might have knee extensor weakness and you should then understand what secondary impairments could occur because of this weakness and what orthoses or assistive devices may be needed.
Got it. Quads are innervated by L2-L4, so knee extensor weakness can occur if these are affected. The secondary impairments would be knee flexion contracture & orthoses that may assist with this is probably a KAFO b/c of possible joint contractures or quadricep muscle weakness or knee joint instability. Is this along your line of thought?
Yes, similar line of thought…although some children with L4 lesions may get away with an AFO. It really all depends on level of strength, overall gait pattern, and sometimes age/size. Tricky lesion level 🙂