Despite the high prevalence of low back pain subacute and chronic symptoms are often referred to as nonspecific in nature indicating that there is no established source of the pain. In the absence of clear pathoanatomical diagnosis patients with nonspecific low back pain are often described as representing a heterogeneous group demonstrating multidimensional signs and symptoms. Current research in physical therapy has focused on developing sensitive and specific clinical tests attempting to sub group these patients into more homogeneous groups. According to the clinical practice guideline individuals with low back pain may be classified using the diagnosis of low back pain with movement coordination impairments based on certain clinical findings. The aim of this manuscript is to offer a review of the literature describing the identification and treatment of patients with low back pain and movement coordination impairments of the trunk. The reader will be presented with available examination paradigms and classification systems that can be used to subgroup patients with nonspecific low back pain with movement coordination impairments to help guide physical therapy examination and treatment. Key Words provide a list of 3 to 4 pertinent words in alphabetical order NOTE do not repeat words that are part of the title.
Trunk stabilization exercises are common practice in physical therapy for the treatment of patients presenting with nonspecific low back pain. Hicks et al 28 developed a clinical prediction rule to assist clinicians in identifying patients with low back pain who will likely benefit from a stabilization based exercise program. A clinical prediction rule CPR is a tool designed to aid in decision making by statistically combining clinical findings to improve the accuracy of diagnosis prognosis or prediction of response to treatment 26. The four variables identified that possess the greatest predictive power for short term treatment success, following a trunk stabilization based exercise program include a positive prone instability test presence of aberrant movements with motion testing straight leg raise greater than 91 degrees and age less than 40 years 28. When attempting to validate this CPR Rabin et al 29 concluded that the presence of aberrant movements and a positive prone instability test were the two variables that increased the likelihood for success with trunk stabilization exercises. The word stabilization suggests a need for the treatment of instability a concept that can become confusing for both patients and clinicians. This interpretation may be due to a misunderstanding of the nomenclature or perhaps due to the lack of an accepted operational definition of instability. Research has been conducted to examine the usefulness of clinical examination findings for identifying confirmed radiographic evidence of excessive motion between vertebrae indicating true spinal instability. Lack of hypomobility during segmental mobility testing and the presence of an increased lumbar range of motion, 53 degrees were found to be predictive LR 12 8 95 CI 79 211 6 of segmental instability using flexion-extension radiographs 6. These clinical findings may be useful to a clinician when radiographic studies are not available, however, if these clinical signs are not present is the need for a trunk stabilization exercise program indicated.
DEFINING MOVEMENT COORDINATION IMPAIRMENTS.
When considering the CPR that attempts to identify patients with low back pain who will likely benefit from a stabilization based exercise program an important clinical finding recognized is the identification of aberrant movement patterns. Aberrant patterns are defined as movements that deviate from the typical or expected movement pattern 31. It has been suggested that aberrant movement patterns may be a manifestation of unresolved underlying muscle dysfunction and motor control impairments contributing to the reoccurrence of symptoms in patients with low back pain 32 33. The aberrant movement patterns referenced by the CPR are included in the Appendix Table 1 Mcgill34 notes that achieving trunk stability is not just a matter of activating a few targeted muscles but it is continually changing as a function of the three-dimensional torques needed to support postures with the necessary stiffness needed in anticipation of withstanding unexpected loads. This principle is also described as anticipatory postural adjustment, a term used to define the muscle activation within supporting lumbar segments that is required to stabilize against anticipated forces and facilitate voluntary peripheral limb movements 35. Research has revealed that there is decreased anticipatory lumbopelvic movement in preparation for extremity movement in patients with low back pain which corresponds to increased spinal displacement 36. Adequate muscle activation is required to prepare for the need to move quickly or to ensure sufficient stiffness in any degree of freedom of a joint which may be compromised with injury 34. This phenomenon emphasizes the importance of identifying and correcting patient-specific movement coordination impairments as multiplanar perturbations are frequently introduced to the spine throughout functional mobility.
CLASSIFICATION SYSTEMS SUB GROUPING MOVEMENT COORDINATION IMPAIRMENTS.
The Guide to Physical Therapist Practice recognizes that a primary goal of the diagnostic process is to classify patients based on clusters of signs and symptoms, not pathoanatomical causes 20. This has led to the development of classification systems to help clinicians identify patients who are likely to respond to a specific treatment approach. A useful classification system should lead to the identification of specific subgroups based on data collected during the initial history and physical examination which in turn can guide the selection of optimal intervention strategies 21. A substantial amount of research has emerged since the introduction of the classification system approach with growing evidence that supports their use for providing superior clinical outcomes compared to the use of alternative management methods 22 23. Two paradigms that appear to be most supported by evidence include O'sullivans Motor Control Impairment MCI classification system and Sahrmanns Movement System Impairment MSI classification system. There is substantial evidence supporting both the MCI17, 37, 38, 39, 40 and the MSI classification systems 42, 44, 45, 47, 48, 49, 50 with no clear winner identified as the superior system. Having a general understanding of each system as well as identifying the similarities between the two systems will assist the clinician in identifying the best examination and treatment approach when presented with a patient demonstrating nonspecific low back pain with movement coordination impairments. O'Sullivan vs Sahrmann Two Different Classification Systems. One Similar Concept OSullivan describes a Motor Control Impairment classification system that is used to subgroup patients with chronic low back pain and motor control impairments providing a framework for the identification of underlying mechanisms and behaviors in order to guide treatment 37, 38. In theory, pain may be associated with loss of functional control around the neutral zone of a spinal segment which is proposed to be secondary to specific motor control deficits of the spines stabilizing musculature 38. These individuals with low back pain demonstrate a complete lack of awareness regarding their tendency to adopt postures and movement patterns that maximally stress their pain-sensitive tissue further exacerbating symptoms throughout functional movements. The theoretical framework behind Sahrmanns Movement System Impairment classification system is very similar describing how low back pain may develop secondary to repeated use of direction-specific stereotypic movement and alignment patterns of the lumbar spine throughout functional mobility 41.
These patterns are characterized by the lumbar spine moving more readily than other joints during performance of peripheral movements or assumptions of postures. This phenomenon described by both classification systems appears to be related to a gradual progression of symptoms and therefore a lack of withdrawal motor reflex response that is coupled with reduced proprioceptive awareness of the lumbopelvic region 38. Repetitive use of these abnormal movement patterns overtime may lead to sub failure magnitude loading to structures that contributes to low back pain symptoms 41. Examination identifying a classification sub group. When determining the patients classification sub group a defined examination process is used to identify the preferred trunk movement patterns and alignments. OSullivans examination places emphasis on both static postures and functional movement patterns that are associated with provocation of symptoms where Sahrmann emphasizes the biomechanical considerations of muscle performance and recruitment patterns that occur at the trunk during introduction of peripheral extremity, perturbations. When a movement impairment is directly related to the provocation of the pain disorder a classification pattern with respect to the direction of pain is established. Both classification systems identify five distinct direction based sub classification categories including a flexion pattern extension pattern and for lack of confusion patterns that deviate from the sagittal plane. In general the direction of abnormal alignments and movements most consistently identified throughout the examination becomes the patients movement impairment category. Details on the specific classification patterns for each system can be found in the Appendix Table 2. The physical examination includes items related to patient reported symptom provocation associated with various positions and movements as well as the clinicians judgment of alignments and movement in different planes. Trunk and extremity movements are examined in a variety of positions including supine prone hooklying quadruped seated and standing. A detailed description of the examination process for each classification system can be found in the Appendix Table 3 and Table 4. The movement impairment patterns identified are thought to be associated with an inability to initiate co contraction of the local muscle system with compensatory movement strategies that often develop in order to stabilize lumbar segments by activating the global muscle system 37. These adaptations and alignment patterns are thought to be related to motor control deficits in recruitment patterns and timing skeletal and muscular performance alterations, stiffness and muscle length. The specific postures and movements that produce the patient's pain must be identified and corrected with the assumption that alignments and movements that deviate from an ideal kinesiological standard will increase pain and continue to provoke symptoms throughout functional movements 42. Intervention Management of pain disorders identified by OSullivans system involves changing the patient's movement and cognitive behaviors based on the individuals specific MCI classification.
There is potential for peripheral and central pain drivers to co-exist where cognitive factors such as fear-avoidance behaviors and poor coping strategies will reinforce disability associated with the MCI disorder 40. Intervention is focused on desensitizing the nervous system by educating the patient on how to control their pain provocative postures enhancing motor control by training movements to avoid repetitive strain on pain-sensitive structures while reducing the peripheral nociceptive drive 38. Sahrmanns system agrees that interventions should incorporate patient-specific corrected movement patterns into static and transitional movements addressing flexibility or strength deficits that may be contributing to altered movements and performing specific exercises focused on correcting movement impairments in positions identified during the structured examination 42. Education is focused on activity modification allowing the patient to independently identify and predict activities that may contribute to symptoms while training the patient to restrict provocative lumbar alignments and movements present during functional activities 48, 49. Emphasis is placed on use of a motor learning intervention model aiming to change movement behavior via physical and cognitive learning. The first stage of this model involves training specific isometric muscle contractions incorporating controlled respiration in both non-weight bearing and weight-bearing positions while maintaining neutral lumbar lordosis 37. The initial focus is on the co-contraction of local stabilizing muscles in both sitting and standing with postural correction emphasizing inhibition of global muscle substitution. The second stage involves refining a particular movement by breaking down faulty movement patterns into components with high repetitions. Continued focus is placed on isolating co-contraction of the local muscle system progressing from neutral lordotic posture to normal spinal movement. Patients are encouraged to carry out corrected movement components on a daily basis utilizing local stabilization muscle contractions for pain control only until they can move in a smooth controlled manner without symptoms The last stage involves a low degree of attention required for correct performance of the motor task where the patient can dynamically stabilize their spine in an automatic manner during functional demands. By providing patients with the capacity to manage their disorder in an effective manner while reducing their fear of movement interventions directly impact both the dominant peripheral nociceptive and secondary cognitive drives for the impairment.
Evaluating and treating patients with low back pain can be a daunting task for even the most experienced clinician Several diagnostic algorithms and classification systems have been developed to help guide the treatment of nonspecific low back pain by identifying subgroups. The Treatment Based Classification TBC system has been used historically as a guide for physical therapists to help direct the treatment of patients with low back pain. This system subgroups patients into 4 different categories based on their likelihood to respond to a particular treatment. The TBC groups include manipulation specific exercise, stabilization and traction 25. These treatment classifications are primarily geared toward pain modification which is often helpful in the initial stages of low back pain. However what if the patient's symptoms no longer respond to the previously prescribed treatment approach as they progress with therapy. Is this an indication that the patient is appropriate for discharge or referral back to the physician. The TBC and CPRs can be helpful tools during the initial screen however the evaluation process must not stop there. Patients with low back pain can often change classification subgroups as their initial pain diminishes. For this reason, the TBC system and CPR should be used as an initial screen to help guide the clinician into further investigation of specific movement coordination impairments using a classification system. After reviewing the literate describing both OSullivans and Sahrmanns classification systems there appear to be several similarities between the two paradigms. Both systems assume that motor control impairments play an underlying role in the development of low back pain disorders. The classification systems also rely on the identification of abnormal lumbopelvic movements using a variety of specific test positions with modification of painful movements to aid in allocation to a specific subgroup that also serves to guide treatment. Both systems encourage the patient to independently identify and predict functional activities that contribute to their symptoms training the patient to restrict provocative lumbar alignment and movements throughout functional mobility The underlying goal of both classification systems is to identify and treat patient-specific abnormal movement patterns that are driving symptoms throughout functional mobility. Patients classified into the stabilization treatment group using the TBC system are often instructed to perform general trunk stabilization exercises such as bridging and quadruped progressions with cueing to maintain a rigid or stable trunk 28. However, as questioned earlier are we truly treating instability in these patients. Individuals with chronic low back pain disorders are often already presenting with abnormally high levels of muscle guarding and co-contraction of the lumbopelvic muscles which appears to be driven by an exaggerated withdrawal motor response to pain 38. This leads to high levels of compressive loading excessive stability resulting in a mechanism for tissue strain and ongoing peripheral nociceptor sensitization. It is also proposed that specific stabilization exercise and treatment approaches that focus on pain modification will often reinforce avoidance behaviors further exacerbating symptoms 38. Cueing these individuals to co contract their trunk muscles to stabilize their spine will likely reinforce an abnormal movement behavior further exacerbating symptoms. Based on this phenomenon perhaps redefining the treatment approach from trunk stabilization to movement coordination exercises is indicated.
CONCLUSION CLINICAL RELEVANCE.
In conclusion, research supports the benefit of subgrouping patients who present with low back pain. Physical therapy interventions that are classification based and geared towards addressing the underlying mechanism driving the disorder aid in altering the patient's condition impacting both the physical and cognitive drivers of pain. Several reliable and valid examination paradigms have been proposed to assist clinicians with subgrouping patients who present with movement coordination impairments of the trunk which in turn can help direct treatment towards movement coordination based exercise approach. The modified CPR may be used initially as a clinical tool to subgroup a patient with nonspecific low back pain as likely to benefit from trunk stabilization exercises However one must consider use of additional classification systems such as Osullivans Motor Control Impairment classification system or Sahrmanns Movement System Impairment classification system to further subgroup patients. This will likely help to better guide the examination and treatment of patients with nonspecific low back pain and movement coordination impairments who are not responding to the typical stabilization based exercise approach.