Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Literature Review

Patients with chronic low back pain have been found to have specific motor dysfunctions . Hodges and Richardson  found that those with a history of low back pain and dysfunction had poor motor control. The local system dysfunction developed after the onset of pain and pathology.

With the occurrence of pain and dysfunction, it is believed that the pain may resolve but that the dysfunction may persist. Research has concentrated on the decrease in function of muscles found in patients with low back pain and on exercise programs that have been found to be effective and to provide improved stability.

They reported “early activation of the transversus abdominis (TrA) and obliquus internus abdominis (OI) with upper limb movement at both fast and intermediate speeds for the control group” . Those with low back pain “failed to recruit transversus abdominis or obliquus internus abdominis in advance of fast movement, and no activity of the abdominal muscle was recorded in the majority of intermediate speed trials”.

It was found that “muscle recruitment associated with limb movement is altered in people with low back pain with movement at a variety of speeds”, and it is believed that exercise should focus on changes in motor control rather than on strength training . Hodges and Richardson also found that the TrA “does not produce trunk movement but contributes to the control of spinal stiffness in a non-direction specific manner.”

O’Sullivan et al. It looked at those patients with clinical instability resulting in chronic low back pain and diagnosed radiologically with spondylolysis and spondylolisthesis. Those authors were able to significantly decrease the pain and increase the functional ability through a specific exercise program aimed at lumbar stabilization. No change was found in the pain level or in the function of the control group, who were treated conservatively by their treating practitioner. They had continued with their regular weekly exercises such as swimming, walking, and gym work.

O’Sullivan et al. It directed some of their research toward patients with a clinical diagnosis of lumbar spine instability in the flexion pattern, and those authors found that they demonstrated an inability to find and to maintain a neutral posture of their lumbar spine when sitting. This loss of position sense or proprioceptive awareness may lead to abnormal loading of the joint surfaces, followed by injuries and degenerative changes over time.

It is hypothesized that a deficit or delay in the timing and ability of the muscle contractions to protect joints from excessive movement in clinical instabilities leads to recurrent injury . Development of proprioception may be assisted by postural retraining and stabilization exercises in neutral postures progressing to unstable surfaces in functional movements and sports. It is beneficial to incorporate proprioception in the treatment of patients with back pain related to lumbar segmental instabilities.

O’Sullivan et al.It further researched the activity of lumbar spine musculature with common postures seen in a painfree population. The passive postures of slumped sitting or sway standing showed a decrease in activity of the lumbopelvic stabilizing muscles.

Conversely, there was an increase in activity of lumbopelvic stabilizing muscles of thoracic erector spinae and internal oblique found in erect sitting and standing postures in the same population. Postural retraining in conjunction with specific exercise stabilization programs of the lumbar spine is supported by research concerning the treatment of low back pain.

O’Sullivan et al.It also found that erect posture in weight-bearing positions would increase the strength of the muscles that provides stability of the lumbopelvic region. “In contrast, facilitation of muscle activity in nonweightbearing or poorly aligned positions may hinder the transfer of improved lumbo-pelvic muscle function into everyday activities”. Strengthening of the lumbopelvic muscle groups would be better achieved in weight-bearing and erect postures to simulate everyday and sporting activities.

Research indicates that deep trunk muscles, including the TrA, the multifidus, the internal oblique, and the diaphragm, will be activated in advance of limb and trunk movement to reduce intervertebral motion in the spine and, therefore, increase spinal stability.

A delay in onset of activation of the TrA with rapid limb movement also was found in those with recurrent low back pain. Researchers have indicated that contraction of the abdominal muscles before movement of the limbs or the trunk may contribute to stabilization of the lumbar spine against forces associated with the limb movement.

The transversus abdominis is activated independent of the direction of trunk movement and activation is continuous. Exercise for the abdominal muscles may facilitate the maintenance of coordination, strength, support, and endurance for the muscles of the pelvic floor. Exercise progressions for the TrA will improve lumbar stabilization.

Lumbar multifidus provides stabilization and control in the lumbar spine . During voluntary arm movements, it was found that the “superficial fibers of multifidus were responsible for the control of spine orientation and the deep fibers of multifidus contributed in the control of intervertebral motion”. The multifidus, lumbar longissimus, and iliocostalis “contribute to the support and control of the orientation of the lumbar spine and the support or stabilization of the lumbar segments” .

Those patients with a first-time episode of lumbar back pain having no radiological pathology were found to have a reduced cross-sectional area of the multifidus at the level of pain as well as dysfunction in the lumbar spine as demonstrated by ultrasound.

A specific exercise program with cocontraction of the TrA and the multifidus produced an increased cross-sectional area of the multifidus and reduced recurrence rate of low back pain as followed over the course of a year. The control group had no improvement in the cross-sectional area of the multifidus with the continuation of normal activities.

Kavcic et al. It found that “as loads are applied to the spine there is an integration of the many different muscles in order to balance the stability and moment demands, and these patterns change as the spine loading patterns change.” They concluded that the focus should not be directed toward one or two single muscle groups to provide the stability of the lumbar spine.

Instead, the exercise programs should be directed toward training many of the potential lumbar spine stabilizers for improved motor patterns, which will change with the functional task. “The role of each individual lumbar muscle changes as the loads placed on the spine changes”. They also concluded that “the smaller muscles have a stabilizing role and that as loads increase, the need for the stronger global muscles is required”.

The supine active straight-leg raise test (ASLR) has been introduced as a valid tool for assessing the load transfer between the trunk and lower extremities. When the lumbopelvic-hip region is functioning optimally, the leg should rise effortlessly from the table. There should be no movement of the pelvis in relation to the thorax and lower extremity , but there should be adequate contraction of the muscles in the local and global systems to stabilize the thorax, lumbar spine, and pelvis while moving the lower extremity.

Mens et al. It have researched the specific relationship between impairment of the ASLR and the increase in pelvic mobility as depicted radiographically and the resulting pelvic pain disorders.

With the ASLR, the patient is in the supine position and is asked to actively raise one straight leg 5 cm above the table without bending the knees. The patient reports the subjective findings, and the examiner observes the movement between the pelvis and lower extremity. A four-point scale is used to rank the weakness observed:

  • 0 = the patient feels no weakness, and the examiner sees no abnormal pattern
  • 1 = the patient feels weakness, but the examiner sees no abnormal moving pattern
  • 2 = the patient feels weakness, and the examiner assesses that raising the leg causes difficulties
  • 3 = the patient is unable to raise the leg

A patient with a difference of one or more points between the left leg and right leg is classified as having an asymmetrical weakness.

This test demonstrates the importance of core stabilization in providing a stable base within the trunk, from which the lower extremities can move with the speed, coordination, and strength required in sports.

Comments are closed.