ABSTRACT
Objectives: The objective of this study was to assess the outcomes of the use of electrodiagnosis in the diagnosis and management of discrete nerve injuries in patients with complex regional pain syndrome (CRPS). Design: This study is a secondary retrospective cohort analysis of patients diagnosed with CRPS from a single outpatient physical medicine and rehabilitation clinic and included all patients who had abnormal electrodiagnostic findings, in addition to CRPS. Results: Sixty patients of 248 diagnosed with CRPS underwent electrodiagnosis, 41 of whom had abnormal electrodiagnostic findings indicating a discrete nerve injury. Only 51% of the 41 referrals had indicated the suspicion of a nerve injury. Nearly all patients had undergone physiotherapy. Forty-one percent responded to treatment with oral prednisone alone, 54% had a functional improvement after a combination of treatments including corticosteroids, and 5% improved with treatments that did not involve corticosteroids. Surgical interventions for nerve injuries were required for 34% of patients in the cohort. All surgeries involved the median or ulnar nerve, with the exception of one fibular nerve. After treatment, 39 of 41 patients had functional recoveries or better. Conclusions: Electrodiagnosis can inform diagnosis of nerve injury and direct intervention including the need for surgical intervention. Electrodiagnosis should be considered for patients with initial signs of concomitant discrete nerve injury or with CRPS who are not responding to treatments because a nerve injury may be underlying.What is Known Complex Regional Pain Syndrome (CRPS) is a poorly understood pain condition. CRPS has been divided into two subtypes, the second subtype involves a discrete nerve injury with pain that extends beyond the territory of the nerve injury.What is New We observed that nerve injuries that may require surgical intervention are diagnosed just over half of the time upon initial assessment in patients with suspected CRPS. We observed that nerve injuries frequently required specifically directed interventions in place of or in conjunction with CRPS treatments. We suggest that electrodiagnosis is an important part of the triage protocol for CRPS II to reveal discrete nerve injuries that may be hidden. We recommend that electrodiagnosis be considered for patients with initial signs of concomitant discrete nerve injury or for CRPS patients who do not improve with medical therapies.
CRPS typically occurs after an injury or inciting event and can be accompanied by severe pain, sensitivity, swelling, changes in the color of the skin, changes in the texture of the skin, changes in hair and nail growth, weakness, muscle wasting, range of motion reduction, and temperature changes in the affected area. Little is known about type II CRPS, which may present with all of the same signs and symptoms as above but with damage to a nerve in the area. This study examined cases of CRPS where patients had electrodiagnostic findings that suggested a nerve injury. We found that the referring physicians reported nerve injuries in just over half of the cases. Oral prednisone was often the chosen treatment for these patients, although many required additional treatments, including surgery, to address their nerve injury. We recommend that electrodiagnosis be considered for patients with CRPS who are not responding to corticosteroids because a nerve injury could be preventing CRPS symptoms from resolving. When the CRPS trigger was a trauma that likely simultaneously injured the nerve, patients needed to have surgery more frequently than those with atraumatic onsets.
