Peter J. Fazey

Nucleus pulposus deformation in response to rotation at L1–2 and L4–5

BACKGROUND Spinal rotation couples with lateral flexion as a composite movement. Few data report the in vivo mechanical deformation of the nucleus pulposus following sustained rotation. MRI provides a non-invasive method of examining nucleus pulposus deformation by mapping the hydration signal distribution within the intervertebral disc. METHODS T1 weighted coronal and sagittal lumbar images and T2 weighted axial images at L1-2 and L4-5 were obtained from 10 asymptomatic subjects (mean age 29, range: 24-34 years) in sustained flexed and extended positions plus combined positions of left rotation with flexion and extension. Nucleus pulposus deformation was tracked by mapping the change in hydration profiles from coronal and sagittal pixel measurements. FINDINGS An average sagittal change in position of 44° (SD 14.5°) from flexion to extension was recorded between L1 and S1 (range: 18°- 60°) resulting in a mean anterior nucleus pulposus deformation of 16% of disc hydration profile (range: 3.5%-19%) in 19/20 discs. When rotation was combined with either flexion or extension, mean coronal deformation was 4.8% (SD-5.1%; range: 0.4%-15%). Lateral nucleus pulposus deformation direction varied in rotation (44% deformed left and 56% deformed right). Intersegmental lateral flexion direction more strongly predicted nucleus pulposus deformation direction with 75% deforming contralaterally. INTERPRETATION Nucleus pulposus deformation direction in young subjects was more predictable following sagittal position change than in rotation combined with flexion or extension. Deformation magnitude was reduced in rotated positions. Intersegmental lateral flexion was a stronger predictor of nucleus pulposus deformation direction.

Low back pain misdiagnosis or missed diagnosis: Core principles

Consensus guidelines for the management of low back pain recommend that the clinician use contemporary best practice for assessment and treatment, consider biopsychosocial factors and, if chronic, use a multimodal and multi-disciplinary approach. Where guidelines are not followed and basic assessment is inadequate the diagnosis may be compromised and the sequelae of errors compounded. Factors such as a lack of knowledge or recognition of the common structure specific pain referral patterns, poor clinical reasoning, inappropriate referral and predilection for popular management approaches also contribute to mis-diagnosis and mis-management. This report describes two cases of chronic low back pain with lengthy histories of multiple failed interventions to highlight the consequences of focussing on a singular approach to the exclusion of evidence based pathways and the resulting risk of a missed diagnosis. The eventual management to mitigate these problems is reported with the aid of low back pain outcome measures, computer-aided combined movement examination, disability and pain questionnaires and health quality of life surveys.