Back Pain with Leg Pain

Association between chiropractic spinal manipulation and gabapentin prescription in adults with radicular low back pain: retrospective cohort study using US data

OBJECTIVES

Radicular low back pain (rLBP) is often treated off-label with gabapentin or by chiropractors using chiropractic spinal manipulative therapy (CSMT). To date, no studies have examined the association between these interventions. We hypothesised that adults under 50 years of age receiving CSMT for newly diagnosed rLBP would have reduced odds of receiving a gabapentin prescription over 1 year-follow-up.

DESIGN

Retrospective cohort study.

SETTING

US network including linked medical records, medical claims and pharmacy claims of >122 million patients attending large healthcare organisations (TriNetX), queried 15 June 2023, yielding data from 2017 to 2023.

PARTICIPANTS

Adults aged 18-49 were included at their first occurrence of rLBP diagnosis. Exclusions were severe pathology, other spinal conditions, on-label gabapentin indications and gabapentin contraindications. Propensity score matching controlled for variables associated with gabapentin use and receipt of prescription medication over the preceding year.

INTERVENTIONS

Patients were divided into CSMT or usual medical care cohorts based on the care received on the index date of rLBP diagnosis.

PRIMARY AND SECONDARY OUTCOME MEASURES

OR for gabapentin prescription.

RESULTS

After propensity matching, there were 1635 patients per cohort (mean age 36.3±8.6 years, 60% women). Gabapentin prescription over 1-year follow-up was significantly lower in the CSMT cohort compared with the usual medical care cohort, with an OR (95% CI) of 0.53 (0.40 to 0.71; p<0.0001). Sensitivity analyses revealed early divergence in cumulative incidence of prescription; and no significant between-cohort difference in a negative control outcome (gastrointestinal medication) suggesting adequate control for pharmacological care preference.

CONCLUSIONS

Our findings suggest that US adults receiving CSMT for newly diagnosed rLBP have significantly reduced odds of receiving a gabapentin prescription over 1-year follow-up compared with those receiving usual medical care. Results may not be generalisable and should be replicated in other healthcare settings and corroborated by a prospective study to reduce confounding.

Referred pain: characteristics, possible mechanisms, and clinical management

Purpose of this review

Referred pain is a common but less understood symptom that originates from somatic tissues. A comprehensive recognition of referred pain is important for clinicians when dealing with it. The purpose of this study is to summarize the current understanding of referred pain, including its pathogenesis, characteristics, diagnosis, and treatment.

Recent findings

Referred pain arises not only from pathologies primarily involving local tissue but also from lesions in distant structures. Central sensitization of convergent neurons and peripheral reflexes of dichotomizing afferent fibers are two theories proposed to explain the pathological mechanism of referred pain. Because syndromes related to referred pain of different origins overlap each other, it is challenging to define referred pain and identify its originating lesions. Although various approaches have been used in the diagnosis and treatment of referred pain, including conservative treatment, blockade, radiofrequency, and surgery, management of referred pain remains a clinical challenge.

Summary

Unlike radicular pain and neuropathic pain, referred pain is a less studied area, despite being common in clinics. Referred pain can derive from various spinal structures, and blockage helps identify the primary pathology. Due to the heterogeneity of referred pain, treatment outcomes remain uncertain. Further studies are needed to improve our understanding of referred pain.

Significance of A-waves in Isolated Calf Pain as a Manifestation of Radicular Pain During F-wave Studies: A Case Report

Although isolated lower leg pain (LPP) without neurological deficit is frequently encountered in clinical practice, some of its aspects remain underexplored in the literature. There is contrasting evidence supporting the use of late responses, namely, F-waves and A-waves, in the assessment of nerve root damage. We describe the case of a 29-year-old female who presented with pain in the left calf. Neurological investigations were only significant for a positive straight leg raise test on the left side. F-wave studies of the left tibial nerve at distal and proximal points of stimulation showed the presence of the A-wave preceding the F-wave, the duration of which was prolonged. One year later, the patient reported new-onset left-sided low back pain with radiation to the gluteal area that appeared after a 10-hour airplane flight. Low back and calf pain were resolved with manipulative therapy. A-waves that had been recorded before F-waves were now no longer detectable. The presence of a neuropathic radicular component was accompanied by subclinical damage to motor fibers, as detected by routine F-waves studies. This case report illustrates the utility of integrating F-wave duration and the presence of A-waves into clinical, neurophysiological, and neuroimaging data in determining pain-generating structures in isolated LLP.

Functional Popliteal Artery Entrapment Syndrome: An Approach to Diagnosis and Management

Popliteal Artery Entrapment Syndrome (PAES) is an uncommon syndrome that predominantly affects young athletes. Functional PAES is a subtype of PAES without anatomic entrapment of the popliteal artery. Patients with functional PAES tend to be younger and more active than typical PAES patients. A number of differential diagnoses exist, the most common of which is chronic exertional compartment syndrome. There is no consensus regarding choice of investigation for these patients. However, exercise ankle-brachial indices and magnetic resonance imaging are less invasive alternatives to digital subtraction angiography. Patients with typical symptoms that are severe and repetitive should be considered for intervention. Surgical intervention consists of release of the popliteal artery, either via a posterior or medial approach. The Turnipseed procedure involves a medial approach with a concomitant release of the medial gastrocnemius and soleal fascia, the medial tibial attachments of the soleus and excision of the proximal third of the plantaris muscle. Injection of botulinum A toxin under electromyographic guidance has recently shown promise as a diagnostic and/or therapeutic intervention in small case series. This review provides relevant information for the clinician investigating and managing patients with functional PAES.

Physical Abilities in Low Back Pain Patients: A Cross-Sectional Study with Exploratory Comparison of Patient Subgroups

An abundance of literature has investigated the association between low back pain (LBP) and physical ability or function. It has been shown that LBP patients display reduced range of motion, decreased balance ability, impaired proprioception, and lower strength compared to asymptomatic persons. The aim of this study was to investigate the differences between LBP patients and healthy controls in terms of several physical abilities. Based on the premised that different biomechanical and physiological causes and consequences could be related to different types of LBP, a secondary exploratory attempt of the study was to examine the differences between LBP subgroups based on the pain location (local or referred) or type of pathology (discogenic or degenerative) on the level of impairment of function and ability. Participants performed range of motion tests, trunk maximal voluntary contraction force tests, a sitting balance assessment, the timed up-and-go test, the chair rise test, and the trunk reposition error test. Compared to the control group, symptomatic patients on average showed 45.7% lower trunk extension (p < 0.001, η² = 0.33) and 27.7 % lower trunk flexion force (p < 0.001, η² = 0.37) during maximal voluntary contraction. LBP patients exhibited decreased sitting balance ability and lower scores in mobility tests (all p < 0.001). There were no differences between groups in Schober’s test and trunk repositioning error (p > 0.05). No differences were observed among the LBP subgroups. The exploratory analyses are limited by the sample size and uncertain validity of the diagnostic procedures within this study. Further studies with appropriate diagnostic procedures and perhaps a different subgrouping of the LBP patients are needed to elucidate if different types of LBP are related to altered biomechanics, physiology, and function.

Does the presence of neuropathic pain affect the outcomes of the interlaminar epidural steroid injection for cervical disc herniation?: A prospective clinical study

Epidural steroid injections (ESI) are commonly performed for the treatment of chronic cervical disc herniation (CDH). Although they are considered to be effective for both nociceptive and neuropathic types of pain, there is a lack of data regarding the impact of neuropathic pain (NP) and nociceptive pain components on treatment outcomes. The aim of this study is to compare the effectiveness of interlaminar epidural steroid injection (ILESI) between patients with predominantly NP and nociceptive pain due to CDH.Sixty five participants were initially included in the study and assessed by numeric rating scale (NRS), neck pain and disability scale (NPDS), short form-12 (SF-12), and self-reported Leeds assessment of neuropathic symptoms and signs (S-LANSS) pain scale at baseline and 1 month, 3 months, 6 months after ILESI.All patients were evaluated at 1st month and 3rd month follow-up periods while 54 of patients achieved to complete 6th month follow-up. There were significant improvements in all outcome measures for all time periods when compared with the pre-intervention scores. At baseline 24 (36.9%) of patients had predominantly NP in accordance with S-LANSS pain scale. The ratio of NP predominant patients reduced to 7.6% at 1st month, 12.3% at 3rd month, and 12.9% at 6th month with a significant difference for each follow-up period when compared with the baseline. Although all NRS and NPDS scores at baseline were significantly higher in patients with NP, improvement was significant at all follow-up periods in both groups. Minimal clinically important change in NRS was observed in >75% of patients at 1st, 3rd, and 6th month in both groups.The results of this study showed that NP is present in one-third of the patients suffering from neck and radiating arm pain due to CDH and cervical ILESI is an effective treatment approach for both neuropathic and nociceptive components of pain.Clinical Trials Registration Number: NCT04235478.

MR-Guided Percutaneous Intradiscal Thermotherapy (MRgPIT): Evaluation of a New Technique for the Treatment of Degenerative Disc Disease in Cadaveric Lumbar Spine

PURPOSE

Evaluation of MR feasibility and real-time control of an innovative thermoablative applicator for intradiscal thermotherapy and histological analysis of laser annuloplasty in human ex vivo intervertebral discs.

MATERIALS AND METHODS

We evaluated a new MR-compatible applicator system for MR-guided percutaneous intradiscal thermotherapy (MRgPIT) in an open 1.0-T MRI-system. Needle artefacts and contrast-to-noise ratios (CNR) of six interactive sequences (PD-, T1-, T2w TSE, T1-, T2w GRE, bSSFP) with varying echo-times (TE) and needle orientations to the main magnetic field (B₀) were analysed. Additionally, five laser protocols (Nd: YAG Laser, 2-6 W) were assessed in 50 ex vivo human intervertebral discs with subsequent histological evaluation.

RESULTS

In vitro, we found optimal needle artefacts of 1.5-5 mm for the PDw TSE sequence in all angles of the applicator system to B₀. A TE of 20 ms yielded the best CNR. Ex vivo, ablating with 5 W induced histological denaturation of collagen at the dorsal annulus, correlating with a rise in temperature to at least 60 °C. The MRgPIT procedure was feasible with an average intervention time of 17.1 ± 5.7 min.

CONCLUSION

Real-time MR-guided positioning of the MRgPIT-applicator in cadaveric intervertebral disc is feasible and precise using fast TSE sequence designs. Laser-induced denaturation of collagen in the dorsal annulus fibrosus proved to be accurate.

Low-Frequency Electroacupuncture Alleviates Chronic Constrictive Injury-Induced Mechanical Allodynia by Inhibiting NR2B Upregulation in Ipsilateral Spinal Dorsal Horn in Rats

OBJECTIVE

To study the effects of electroacupuncture (EA) in chronic constrictive injury (CCI) rat model and the expression of N-methyl-D-aspartate receptor type 2B (NR2B) in ipsilateral spinal dorsal horn in rats to explore the analgesic mechanisms of EA.

METHODS

According to the random number table, totally 180 rats were evenly divided into a sham group, a CCI group, and an EA group. CCI model was conducted with four 4-0 chromic gut ligatures loosely ligated around the left sciatic nerve 1 cm above the trifurcation. Rats in the EA group received 2 Hz EA therapy bilaterally at acupoints of Zusanli (ST 36) and Sanyinjiao (SP 6) once daily (30 min/d) for 30 days after surgery. Paw withdrawal thresholds (PWTs) were measured on 0 (baseline), 1, 3, 7, 15, 30 days after surgery. Rats were sacrificed on 0, 1, 3, 7, 15 and 30 days after surgery, and the L4-5 segments of spinal cord were removed to detect the expression of NR2B by immunohistochemistry and quantitative polymerase chain reaction.

RESULTS

PWTs in the CCI group were significantly lower than the sham group at Day 1-30 after surgery, and reached its lowest at Day 1 (P<0.01). After EA treatment, the PWTs recovered rapidly and were significantly higher than those in the CCI group on 3, 7, 15 and 30 days after surgery (P<0.01). The numbers of NR2B-immunoreactive cells of the CCI group significantly increased after CCI surgery compared with the sham group (P<0.01). Compared with the CCI group, stimulation of EA markedly decreased the numbers of NR2B-immunoreactive cells at Day 3, 7, 15 and 30 (P<0.05). In the sham group, NR2B mRNA was expressed at a low level. It increased after CCI surgery, which increased rapidly at Day 7 (P<0.01) and reached its peak value at Day 15 (P<0.01). After EA stimulation, relative quantity of NR2B mRNA expression was less than that in the CCI group at Day 15 and 30 (P<0.05).

CONCLUSIONS

Low frequency of EA had antinociceptive effect in CCI rat model. The analgesic effects of EA might be through the inhibition of NR2B.