Theoretical Schemas to Guide Back Pain Consortium (BACPAC) Chronic Low Back Pain Clinical Research.

BACKGROUND: Chronic low back pain (cLBP) is a complex with a heterogenous clinical presentation. A better understanding of the factors that contribute to cLBP is needed for accurate diagnosis, optimal treatment, and identification of mechanistic targets for new therapies. The Back Pain Consortium (BACPAC) Research Program provides a unique opportunity in this regard, as it will generate large clinical datasets, including a diverse set of harmonized measurements. The Theoretical Model Working Group was established to guide BACPAC research and to organize new knowledge within a mechanistic framework. This article summarizes the initial work of the Theoretical Model Working Group. It includes a three-stage integration of expert opinion and an umbrella literature review of factors that affect cLBP severity and chronicity. METHODS: During Stage 1, experts from across BACPAC established a taxonomy for risk and prognostic factors (RPFs) and preliminary graphical depictions. During Stage 2, a separate team conducted a literature review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to establish working definitions, associated data elements, and overall strength of evidence for identified RPFs. These were subsequently integrated with expert opinion during Stage 3. RESULTS: The majority (∼80%) of RPFs had little strength-of-evidence confidence, whereas seven factors had substantial confidence for either a positive association with cLBP (pain-related anxiety, serum C-reactive protein, diabetes, and anticipatory/compensatory postural adjustments) or no association with cLBP (serum interleukin 1-beta / interleukin 6, transversus muscle morphology/activity, and quantitative sensory testing). CONCLUSION: This theoretical perspective will evolve over time as BACPAC investigators link empirical results to theory, challenge current ideas of the biopsychosocial model, and use a systems approach to develop tools and algorithms that disentangle the dynamic interactions among cLBP factors.

Motor amplitudes may predict electromyography-confirmed radiculopathy in patients referred for radiating limb pain.

INTRODUCTION: Radiculopathy is diagnosed by needle electromyography, with nerve conduction studies excluding alternative diagnoses. METHODS: In patients referred for electrodiagnostic evaluation of radiating limb pain, we compared ulnar motor amplitudes between those with and without electromyographically confirmed C8 radiculopathy, as well as fibular motor amplitudes between those with and without electromyographically confirmed L5 radiculopathy. RESULTS: Patients with electromyographically confirmed C8 or L5 radiculopathy demonstrated decreased ulnar or fibular motor amplitudes, respectively, as compared to patients without radiculopathy. Receiver operating characteristic curves demonstrated good diagnostic accuracy, with areas under the curve of 0.85 and 0.82, respectively. Optimal cut-offs for electromyographically confirmed C8 and L5 radiculopathies were 10.2 mV and 3.6 mV, respectively, with associated sensitivities/specificities of 0.86/0.74 and 0.92/0.60. DISCUSSION: Ulnar and fibular motor amplitudes may have clinical utility in assessing the likelihood of patients demonstrating electromyographically confirmed C8 and L5 radiculopathies with active denervation. The findings may be particularly useful in patients intolerant of needle electromyography. Muscle Nerve 59:561-561, 2019.

Entrapment neuropathies of the lower extremity.

Neuropathies that affect the lower limbs are often encountered after trauma or iatrogenic injury or by entrapment at areas of anatomic restriction. Symptoms may initially be masked by concomitant trauma or recovery from surgical procedures. The nerves that serve the lower extremities arise from the lumbosacral plexus, formed by the L2-S2 nerve roots. The major nerves that supply the lower extremities are the femoral, obturator, lateral femoral cutaneous, and the peroneal (fibular) and tibial, which arise from the sciatic nerve, and the superior and inferior gluteal nerves. An understanding of the motor and sensory functions of these nerves is critical in recognizing and localizing nerve injury. Electrodiagnostic studies are an important diagnostic tool. A well-designed electromyography study can help confirm and localize a nerve lesion, assess severity, and evaluate for other peripheral nerve lesions, such as plexopathy or radiculopathy.

Using Lean principles to manage throughput on an inpatient rehabilitation unit.

Performance improvement is a mainstay of operations management and maintenance of certification. In this study at a University Hospital inpatient rehabilitation unit, Lean management techniques were used to manage throughput of patients into and out of the inpatient rehabilitation unit. At the start of this process, the average admission time to the rehabilitation unit was 5:00 p.m., with a median time of 3:30 p.m., and no patients received therapy on the day of admission. Within 8 mos, the mean admission time was 1:22 p.m., 50% of the patients were on the rehabilitation unit by 1:00 p.m., and more than 70% of all patients received therapy on the day of admission. Negative variance from this performance was evaluated, the identification of inefficient discharges holding up admissions as a problem was identified, and a Lean workshop was initiated. Once this problem was tackled, the prime objective of 70% of patients receiving therapy on the date of admission was consistently met. Lean management tools are effective in improving throughput on an inpatient rehabilitation unit.

Acquired peripheral neuropathy.

The element of time is a crucial factor in the electrodiagnostic presentation of PN. The characteristic changes seen in various neuropathies evolve over time. If testing is performed very early in the course of the disease, abnormalities may not yet be present, in part, because the range of normal values for NCS parameters is broad. In addition, if the process is asymmetric, the affected nerves may not be sampled. Very late in the course of the disease, a multifocal process may appear diffuse and symmetric as the areas of focal involvement coalesce. A primarily, demyelinating process may begin to demonstrate secondary axonal involvement. In very severe neuropathies, it may become difficult to evoke any NCS responses to characterize the neuropathy. It is essential to place the electrodiagnostic findings within the context of the clinical progression to avoid drawing erroneous conclusions. Sometimes, the true nature of the neuropathy is clear only after sequential testing. The etiologic diagnoses of acquired polyneuropathy are vast. A well-crafted electrodiagnostic evaluation can categorize neuropathies into more specific diagnostic groups by identifying the descriptive diagnosis, significantly narrowing the list of possible etiologic diagnoses. Electrodiagnostic testing, which always starts with a pertinent history and physical examination, should always be viewed as a continuation and quantification of the physical examination. Only by knowing the extent and pattern of the clinical involvement is it possible to formulate a thorough electrodiagnostic evaluation. This knowledge is especially important in cases in which the presentation is multifocal, because the neuropathy can be missed entirely if the affected nerves are not evaluated. When evaluating a neuropathy, there are three important questions to answer: (1) Is the process diffuse or multifocal? (2) Is it demyelinating or axonal? (3) Does it predominantly involve the motor or sensory nerves? By assessing the neuropathy along these three axes, the large number of possible etiologic diagnoses becomes much more manageable.