Clinical Presentation of Nerve Lesions

Abstract

In peripheral nerve surgery, treatment planning must begin with an accurate anatomical and neurological assessment in order to judge which nerve or combinations of nerves have been injured.We have found it helpful to bear in mind the comparability of the nerve ramifications of the upper and lower limbs (see Chap. 2). Each nerve of the arm corresponds to a special nerve of the leg and significant distinctions do not exist, with the exception of levels of ramification. Thus, clinical investigation will clearly assess which nerve is actually involved. Unfortunately, however, this examination will reveal nothing about the chances of spontaneous recovery: the time span between nerve lesion and potential and expected regeneration often lasts several months. During this period, we can test the behavior of the axon sprouts only by eliciting the Tinel sign. Palpation and percussion of the affected nerve trunk at different points will trigger an electric-current-like pain that is individually experienced in the sensitive area previously belonging to the injured nerve. The maximum point where the physician can effect such a triggered pain derives from the location of the maximum number of outgrowing axon sprout ends. If the trigger point moves downward during a period of some months, axon outgrowth is occurring, a positive prognostic factor. If the trigger point stops at the same level over several investigations, the outgrowth of axon sprouts is completely blocked, indicating surgical intervention. Under special circumstances, the trigger point of the Tinel sign may even return to the lesion during a short follow-up period, thus indicating increasing compressing forces by scar tissue strangulation mentioned in Chap. 2. According to Seddon’s classification, in all cases of axonotmesis, the Tinel sign is the only real aid in decision making.