Criteria: Table 16-10 Determining Impairment of the Upper Extremity Due to Sensory Deficits or Pain Resulting from Peripheral Nerve Deficits (482) Table 16-15 Maximum Upper Extremity Impairment Due to Unilateral Sensory or Motor Deficits or to Combined 100% Deficits of the Major Peripheral Nerves (492) Table 16-11 Determining Impairment of the Upper Extremity Due to Motor and Loss-of-Power Deficits Resulting from Peripheral Nerve Disorders Based on Individual Muscle Rating (484).
Guidance: Carpal tunnel syndrome impairment assessment is discussed in Section 16.5d, Entrapment/Compression Neuropathy (491-495), and specifically on page 495. The Guides notes that “only individuals with an objectively verifiable diagnosis should qualify for a permanent impairment rating. The diagnosis is made not only on believable symptoms but, more important, on the presence of positive clinical findings and loss of function. The diagnosis should be documented by electromyography as well as sensory and motor nerve conduction studies” (493). “The sensory deficits or pain, and/or the motor deficits and loss of power, are evaluated according to the impairment determinations method described in Section 16.5b. In compression neuropathies, additional impairment values are not given for decreased grip strength. In the absence of CRPS, additional impairment values are not given for decreased motion.” (494) The Fifth Edition states on page 495 that: If, after an optimal recovery time following surgical decompression, an individual continues to complain of pain, paresthesias, and/or difficulties in performing certain activities, three possible scenarios can be present: 1. Positive clinical findings of median nerve dysfunction and electrical conduction delay(s): the impairment due to residual CTS is rated according to the sensory and/or motor deficits as described earlier. 2. Normal sensibility and opposition strength with abnormal sensory and/or motor latencies or abnormal EMG testing of the thenar muscles: a residual CTS is still present, and an impairment rating not to exceed 5% of the upper extremity may be justified. 3. Normal sensibility (two-point discrimination and Semmes-Weinstein monofilament testing), opposition strength, and nerve conduction studies: there is no objective basis for an impairment rating.) According to Table 16-15 Maximum Upper Extremity Impairment Due to Unilateral Sensory or Motor Deficits or to Combined 100% Deficits of the Major Peripheral Nerves (492) the maximum loss for the median nerve is 39% upper extremity impairment for sensory deficits and 10% upper extremity impairment for motor deficits. Sensory deficits are graded by Table 16-10 Determining Impairment of the Upper Extremity Due to Sensory Deficits or Pain Resulting from Peripheral Nerve Deficits (482). If the entire median nerve is involved this sensory deficit is multiplied by the maximum loss of 39% upper extremity impairment. Motor deficits are graded by Table 16-11 Determining Impairment of the Upper Extremity Due to Motor and Loss-of-Power Deficits Resulting from Peripheral Nerve Disorders Based on Individual Muscle Rating (484). If the entire median nerve is involved this motor deficit is multiplied by the maximum loss of 10% upper extremity impairment. These impairments are combined.
