Concerns related to the accurate identification of anterior derangement syndrome in mechanical diagnosis and therapy for low back pain: A case report

Background: In Mechanical Diagnosis and Therapy (MDT), patients with low back pain (LBP) are classified into subgroups to guide a management strategy. A common subgroup where symptoms improve with lumbar extension is labeled posterior derangement syndrome. A less common subgroup where symptoms improve with lumbar flexion is labeled anterior derangement syndrome. Case Presentation: The patient was a 23-year-old woman with intermittent LBP and discomfort over the left lower extremity was initially diagnosis with posterior derangement syndrome. At the initial and second consultations, postural correction and home exercises with lumbar extension were prescribed. However, at the third consultation, sustained lumbar extension revealed worsening of symptoms and function, which resulted in a revised diagnosis of anterior derangement syndrome. Complete recovery was achieved using exercises with lumbar flexion over 6 weeks. Outcomes: The patient wore the LUMOback in daily life, which is a wearable device measuring pelvic angle and acceleration, for 1 week before the initial MDT consultation and for 6 weeks until discharge. The posture scores (%) is the proportion of time in a week with neutral pelvic tilt. In this patient, the posture score decreased greater than a minimum detectable change of 11.7% when MDT classification changed to anterior derangement. Conclusions: This case report indicates the importance of sustained loading to identify the correct derangement syndrome, and follow-up sessions to confirm or reject the initial diagnosis by monitoring symptom and functional changes carefully. Habitual posture may be associated with reduction and aggravation of symptoms.