The relationship between clinical status and preoperative and intraoperative dermatomal somatosensory-evoked potentials was investigated as a function of test site. Results indicated that the specificity and sensitivity of dermatomal somatosensory-evoked potentials varied with level of involvement: L5 demonstrated greatest agreement with equal correlation at L3, L4, and S1. Variables that influenced correlation included history of previous surgeries, type of anesthetic used, interpretation criteria, and whether the patient was awake or asleep. It was concluded that dermatomal somatosensory-evoked potentials can provide the surgeon with diagnostic and intraoperative information regarding the functional integrity of single nerve root function.