A mechanical diagnosis and treatment (MDT) approach for a patient with discogenic low back pain and a relevant lateral component: a case report (2024)

Abstract

Patients with a lateral lumbar shift are often managed with a frontal plane, manual correction first described by McKenzie. However, there is a subset of patients that require a frontal plane correction who do not demonstrate a lateral shift. Both of these patient groups have what is termed a relevant lateral component (RLC). The subset of patients who have an RLC, without a shift, has received very little attention in the literature to date. This case report describes a patient with no shift who had a remarkable disc extrusion identified by magnetic resonance imaging (MRI). The patient responded nicely to a combination of frontal and transverse plane loading strategies in six treatments using the mechanical diagnosis and treatment (MDT) evaluation and treatment system. The case report is unique in the literature in that it describes a patient with no apparent frontal plane, lumbar deformity that had documented evidence of a large disc extrusion and who responded to a variation of McKenzie’s flexion–rotation mobilization. The centralization phenomenon was demonstrated immediately when a non-weight bearing, multiplanar, loading strategy was administered.

Patient characteristics

The patient was a 40-year-old college professor and African-American female referred by a nurse practitioner (TH) with a diagnosis of a ‘large’ L5-S1 disc herniation and left S1 radiculopathy. The patient was 5′5″ tall and weighed 224 pounds. During her initial presentation to the nurse practitioner in December 2009, she reported a visual analog score for pain at 6/10. The pain was located in the left buttock and posterior thigh. It had been present since early November (∼5–6 weeks) and commenced, she believed, as a result of her participation in a weight-control exercise program. The program included wall sits, curl ups, wall push-ups, and side steps. She used elastic band resistance with some of the exercises. The pain began approximately 1 week after initiating the exercise program. It was worse when she bent forward, climbed stairs, or would lie prone. She noted that standing, sitting, and walking would inconsistently increase her pain. She also reported that the pain was generally worse early in the morning. It regularly disturbed her sleep. She reported a positive Valsalva sign; worse with coughing, sneezing, and during bowel movements. Fetal positioning, especially on the left side, was the position of greatest comfort. She denied any lower extremity weakness but did report paresthesias into the left posterior thigh.

Her straight leg raise produced minimal lower extremity symptoms at 90° on the left. Her lower extremity deep tendon reflexes were 2+ and equal with the exception of the left ankle jerk, which was graded at 1+. She also had circumferential numbness in the left calf and foot. She was given a Medrol dose-pack and referred to a physical therapist and certified MDT practitioner (BW).

The patient’s medical history was notable only for bipolar disorder and hypercholesteremia. She was taking prednisone (Medrol dose pack) and Naproxen at intake to the physical therapy facility where she was seen. In addition, she was on a muscle relaxer (name she could not recall), Celexa, Lovastatin, and Abilify. She had no surgical history, reported no history of significant accidents or falls, and denied unremitting night pain. She had had physical therapy 2 years prior for a LBP problem that resolved with conservative care.

For the current episode of LBP, the patient had received physical therapy at another facility. The therapist at the first facility was also a credentialed MDT practitioner. The treatment the patient received from the initial physical therapy encounter consisted of extension-biased exercises, including repeated press-ups from prone (extension in lying)and repeated extension in standing. In addition, she received extension mobilization.9 The patient in this case study believed that the treatment aggravated her back and lower extremity symptoms and after 3–4 weeks of therapy she elected to stop treatment.

Examination

Clinical impression

At this juncture, the therapist had seemingly uncovered a RLC in a patient with no apparent lateral shift. Furthermore, the sagittal plane loading strategies had produced undesirable responses. Positive, though not lasting, changes were evident in the frontal plane. In the MDT system, the provisional classification for this patient is a unilateral/asymmetrical, above-knee derangement.9 In that system, proper management for this patient is to introduce a frontal plane component after exhausting the sagittal plane loading strategies. Even though the therapist had not explored the non-weight bearing repeated sagittal motions, the clinical reasoning supporting frontal plane exploration was further validated by the often overlooked mechanical response that must accompany the proximal migration of symptoms in order to have true centralization.8^,9^,19 When this occurs, in the context of a single session, and is accompanied by proximal migration of the symptoms, there is little doubt that the patient has a reducible derangement. The patient had in fact exhibited a progressive increase in her left side glide before the eighth repetition of that loading strategy began to exacerbate her symptoms.

Intervention

The therapist chose to introduce left lumbar side bending by placing the patient over a pillow in a left lateral recumbent position. He used a non-weight bearing position because, as noted, the weight bearing side glide produced an increase in her symptoms after eight repetitions. Transverse plane motion was also introduced via repeated right rotation from the left side bent position (Fig. 2). This combined motion abolished the patient’s pain completely and restored considerable ROM in the sagittal plane when the patient was tested again in standing. The treatment introduced by the therapist is equivalent to the flexion–rotation mobilization9 with the notable difference being that the motion is coming from below (i.e., via the lower extremities) in the latter method. The patient was sent home with instructions in posture considerations and a single home exercise, replicating the repeated right rotation in left side lying 6–8 times a day.

Outcome

Discussion

This case report presents a patient that had a large disc extrusion identified through MRI that created a RLC. The patient had a remarkable response to a combination of frontal and transverse plane loading strategies. Patients who have a positive response to loading strategies are described as having a directional preference and can be sub classified accordingly.9^,12 Fritz et al.,12 for example, portrayed this in a clinical commentary on treatment-based classification of non-specific LBP. Patients with a directional preference were classified into a ‘specific exercise’ sub group, depending on whether repeated flexion, extension, or lateral shifting led to an improvement of the patient’s symptoms and increased ROM. A criterion for patients who fit into the specific exercise/lateral shift classification is a ‘visible frontal plane deviation of the shoulders relative to the pelvis’. This reflects the tendencies in the literature to date; that is, to associate patients requiring a frontal plane intervention with those who present with an obvious shift. The current patient, even without a visible shift, most likely belonged in the lateral shift sub classification described by Fritz et al.,12 given that she responded to non-sagittal loading strategies. The therapist’s utilization of MDT loading strategy principles, i.e., effectively performing a lateral recumbent version of the flexion–rotation mobilization,9 provides potential evidence for some discretion in the clinical application of those principles.

Santolin21 presented a case study on a patient with similar findings to the current patient. Moreover, the patient had no visible shift, had poor response to sagittal loading strategies, and was classified in the original MDT system as a Derangement three (D3). The patient, however, had no lower extremity symptoms and no imaging to confirm the presumed diagnosis. In addition, the patient was managed with a multimodal intervention strategy, including spinal manipulation and electrical stimulation modalities. Inasmuch, the patient might have been classified, in the treatment-based classification proposed by DeLitto et al.,22 into a mobilization/manipulation subgroup or an exercise/lateral shift subgroup. Since both intervention strategies were used it is difficult to substantiate which intervention actually contributed to the relief seen in this case study.20

A ‘dynamic internal disc model’ has been proposed in the literature,6 the basis of which was originally set forth by McKenzie.5 In that model, if the annulus is competent and the disc’s hydrostatic properties are intact, then the requisite elements are in place for centralization to occur. Donelson et al.6 demonstrated the model’s validity on 63 patients with back pain and ‘variable degrees of lower extremity pain and altered sensation’. In that study, patients who centralized had demonstrated annular competence (91% of 23 patients with a positive discogram) and intact hydrostatic properties of the involved disc.6 In view of the dynamic internal disc model and given the MRI findings on the current patient, it is conceivable that the patient’s response to the interventions were founded upon application of the appropriate loading strategies in a non-herniated (extruded) disc. Annular competence was apparently intact, in spite of the dimensions of the extrusion.

One must consider the influence of the oral steroid. Given that the patient was started on a Medrol dose pack 4 days prior to the initial evaluation by the therapist, it is likely that a combination of mechanical and chemical influences on the disc are to be credited with the ultimate resolution of this case. Nonetheless, there is at least indirect evidence that the loading strategies’ influence was meaningful, if not significant, especially when considering that the patient had had a course of extension-based interventions previously that resulted in an unsatisfactory outcome. The patient demonstrated the same poor response to sagittal plane loading strategies with both physical therapists. It was not until the novel, non-sagittal loading strategies were implemented that the patient began to experience meaningful and lasting relief of symptoms. This led to the appropriate sub classification and interventions within the context of the MDT system.

Conclusion

This case outlines a treatment approach for a large disc extrusion identified through MRI using a combination of a frontal and transverse plane loading strategy. Future studies should investigate the influence of loading strategies on a large group of patients with discogenic pathology validated by discography. Non-sagittal interventions should be explored for their utility in managing patients with and without concordant discography findings. Randomization of patients with non-specific LBP into groups receiving MDT and non-MDT based interventions would offer potential insight into the value of the former in managing this patient population. Finally a randomized, controlled trial that considers the presence or absence of lateral shifts and/or RLCs would potentially provide a meaningful analysis of which patients are best suited for the interventions outside the sagittal plane.

References