Inequality in Leg Length & Lumbar Disc Herniation

This week from Dr. Cerami and Utah Sports and Wellness

From: Journal of Craniovertebral Junction Spine, April-June 2016

Quick Summary:

These authors evaluated 39 subjects with leg length discrepancy and low back pain and 43 controls to quantify the occurrence of disc herniation between the two groups. Traditionally, surgery has been the primary approach in the treatment of discogenic low back pain. However, “the surgical treatment of ruptured lumbar intervertebral discs is sometimes discouraging to both the surgeon and the patient.” This study, for the first time, shows that disc herniation may actually occur as a result of the leg length inequality. “Leg length discrepancies “may lead to disorders in postural movement coordination. It may lead to significant changes in spinal posture and deterioration of postural stability.” “Human coronal balance may be one of the causes of operative failure after disc surgery. Assessment of pathologic coronal imbalance requires a clear understanding of normal coronal alignment.” “These authors suggest that the surgical treatment of lumbar disc herniation does not always lead to improved outcome because of “abnormal coronal balance.” “Correction of abnormal load transmission across the spine and degenerated disc may, therefore, be beneficial.”

Abstract:

Inequality in leg length may lead to to abnormal transmission of load across the endplates and degeneration lumbar spine and the disc space. There has been no study focusing on lumbar disc herniation (LDH) and leg length discrepancy. This subject was investigated in this study. Consecutive adult patients with leg length discrepancy and low back pain (LBP) admitted to our department were respectivelly studied. A total number of 39 subjects (31 women and eight men) with leg length discrepancy and LBP and 43 (25 females and 18 males) patients with LBP as a control group were tested. Occurrence of disc herniation is statistically different between patients with hip dysplasia and control groups (P < 0.05). The results of this study showed a statistically significant association between leg length discrepancy and occurrence of LDH. The changes of spine anatomy with leg length discrepancy in hip dysplastic patients are of importance in understanding the nature of LDH.

These authors also note:

• Low back pain has a lifetime prevalence of 85%.
• The primary cause of LBP is disc disease.
• “Inequality in leg length may lead to to abnormal transmission of load across the endplates [causing] degeneration of the lumbar spine and the disc space.”
• “One of the essential roles of the spine is to support mechanical loads in the upright position. Balance of the body essentially depends on how far the head is to the midline.”
• Spinal imbalance may be an important cause for failed back surgery cases.
• “Subtle anatomic abnormality in the pelvis is associated with altered mechanics in the lumbar spine.”
• Short extremity length and lumbar disc herniation were statistically coupled in this study. “Occurrence of disc herniation is statistically different between patients with short leg and controls.” “Our result showed statistically significant difference.”
• “Patients with chronic LBP have a minor balance defect. Inequality in leg length is important for the understanding of the pathophysiology of lumbar disc degeneration and herniation.”
• “Patients with intervertebral disc disease are characterized by asymmetrical leg loading.” “Leg length discrepancy may be another causative condition” in low back pain.
• “An asymmetrical loading pattern may deteriorate spine biomechanics.”
• “A coronal imbalance of the spine is usually noted in patients with leg length discrepancy.” “Abnormal patterns of load transmission may be accepted as a principal cause of degenerative changes in these cases.”
• “Our observations suggest that LBP may have etiologies related to abnormal load transmission due to coronal imbalance. It seems that a successful treatment may sometimes exist beyond good surgery. In these situations, abnormal coronal balance may be an important factor.”
• “The results of this study showed a statistically significant association between leg length discrepancy and occurrence of lumbar disc herniation.”