Wednesday, August 7, 2013

Altered Breathing Patterns in Chronic Low Back Pain


All readers are aware that chronic low back pain (CLBP) can be debilitating, often requiring multimodal intervention including manual therapy (manipulation, soft tissue therapy), general and specific exercise, modalities, acupuncture, tissue sparing strategies, ergonomic advice, and so on. One aspect that is frequently ignored (I will admit that I am often guilty of this) is the assessment and rehabilitation of breathing patterns. Breathing is a fundamental, automatic part of our daily lives, yet very few of us ever consciously pay attention to how we breathe, let alone how our patients breathe. There is an interesting and growing body of evidence emphasizing the importance of the mind-body connection, as well as relaxation and stress management as they pertain to chronic pain management - breathing assessment connects nicely to these concepts.

Breathing also relates to spinal stability - the diaphragm represents the top of the "muscular cylinder" that supports and moves the lumbar spine (the bottom being the pelvic floor). The diaphragm is responsible for many tasks - regulating intra-abdominal pressure, contributing to lumbopelvic stability, and of course maintaining ventilation. In healthy subjects, the diaphragm has no trouble performing this multi-faceted role.

Further, during pain syndromes or after trauma, it has been established that the strategies employed by the central nervous system to control trunk muscles may be altered. For example, a previous study suggested that those with sacroiliac joint pain displayed impaired kinematics of the diaphragm and pelvic floor, which are thought to be neurologically connected. Commonly, the observed impairments include patients "holding their breath" while they perform dynamic tasks. This constant contraction of the diaphragm during breath holding likely represents a compensatory strategy to increase lumbopelvic stability (I would suggest that they may be "unable to breath" for fear of becoming unstable?). Such impairments have been reversed after motor control rehabilitation programs, suggesting that this is a parameter that we can positively affect. Although the exact relationship has not been delineated, there seems to be a correlation between postural/movement control and respiratory function.

The purpose of this study was to evaluate the breathing patterns in CLBP patients and also healthy subjects in both standing and supine positions, under three different conditions:

1. spontaneous breathing
2. deep breathing
3. during 3 different motor control tasks

Pertinent Results:

at rest, no significant differences were noted between healthy controls and CLBP patients in the supine position (p > 0.05)
in a standing position, there were no differences with quiet breathing, but differences were noted during deep inspiration (p 0.01), but were related to dysfunctions in motor control (p = 0.01)
none of the healthy subjects changed their patterns during the ASLR or BKFO (see below), while 5/10 and 6/10 CLBP patients respectively altered their patterns
pressure biofeedback unit (PBU) measures were altered in CLBP patients compared to controls

Clinical Application & Conclusions:

Ten healthy subjects and 10 patients with CLBP participated in this case-control study. CLBP patients were between the ages of 18-65 with insidious onset LBP of greater than 3 months duration that was limiting their function. They had to receive a diagnosis of non-specific mechanical LBP from a physician. Controls were had no previous history of LBP or other serious disease.

Breathing patterns were assessed by one clinician both visually and via palpation (the clinician was blinded as to whether the subject was in the control or CLBP group). Costodiaphragmatic breathing, defined as a displacement of the ribcage in cranial, lateral outward and ventral directions AND outward abdominal movement - reversed on expiration, was considered the ideal pattern. Paradoxical breathing, upper costal breathing, mixed patterns, and breath holding were all considered as impairments - these patterns have been shown to adversely influence alveolar ventilation.

Breathing patterns were assessed in both standing supine positions during the following conditions:

1. Spontaneous Breathing - no specific instructions given
2. Deep Breathing - patients were instructed to take a "deep breath"
3. During 3 Motor Control Tasks - see below

Motor Control Tasks:

1. Active Straight Leg Raise (ASLR): with the patient lying supine, one leg at a time was lifted 20cm off the table and held for 10 seconds
2. Knee Lift Abdominal Test (KLAT): with the patient supine in crook lying position, they were instructed to lift one foot off the table with the hip and knee in 90簞 of flexion while keeping the lumbar spine stable
3. Bent Knee Fall Out (BKFO): with the patient supine in crook lying position with one leg straight and one bent, they lowered the bent leg to approximately 45簞 of abduction/lateral rotation while keeping the foot against the straight leg - then they returned to the starting position

During all motor tasks and all supine conditions, a pressure biofeedback unit was placed under the lumbar spine - excessive pressure changes indicate movement in the lumbar region - normally a flattening of the lumbar lordosis. Subjects were not informed that breathing patterns were being evaluated to avoid potential influence. After each test, all subjects completed a Visual Analogue Scale (VAS) to assess the severity of their LBP and a BORG exertion scale.

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