Radiculopathy is a neurological state where a peripheral nerve or its root is being blocked and conduction cannot take place. Clinical signs and symptoms include numbness, weakness and diminished reflexes (Bogduk 2009). Monoradiculopathy involves the irritation of a single nerve root; and is the most common type. Acute, idiopathic, polyradiculopathy presents with multiple nerve root involvement in conditions such as Guillain-Barre Syndrome where the peripheral nervous system is affected as a whole (James et al 2010).
Radicular pain and radiculopathy are not synonyms terms although they are often associated. Lumbar radicular pain is radiating pain into one or more lumbar dermatomes, caused by compression and/or inflammation of the nerve root. Radiculopathy is a syndrome which will present with specific neurological signs and possibly radicular pain (Van Boxem & Cheng et al 2010).
Lumbar radiculopathy occurs through different mechanisms; lumbar disc herniations are the most common diagnosis in clinical spine practice and it is thought that the mechanical effect of a herniated disc on a sensitised nerve root is the main factor generating radiculopathy patients under 50 years of age (Rhee, Schaufele & Abdu 2006)(Weber 1994). Spinal stenosis can cause radiculopathy by a narrowing of the spinal canal which can arise from prolapsed disc material, osteophytes, tumor or any other lesion which occupies space in the spinal canal causing compression (Dandy & Edwards 2009). Lateral recess stenosis is a narrowing of the intervertebral foramen which can result in impingement of the nerve root and is a major cause of radiculopathy on patients over 50 years of age (Colak & Topuz 2008).
Lumbar radiculopathy can be treated surgically or conservatively. Common interventions for conservative treatment include oral medications, epidural steroid injections and physical medicine which is inclusive of but not limited to physiotherapy, McKenzie approach, traction, electrotherapy and acupuncture, (Rhee, Schaufele & Abdu 2006).
The basis for this review is to identify a wide range of treatment modalities used within the scope of current physiotherapy practice and assess their efficacy.
Evidence base for physiotherapy treatment
An outcome study conducted by Saal and Saal (1989) demonstrated a good / excellent outcome for 90% of 64 patients suffering from lumbar herniated discs with radiculopathy after undergoing ‘aggressive physiotherapy treatment’ which included back school and stabalisation exercises. This study showed a valid inclusion criteria but did not detail outcome measures, which in turn lacked detail and validity in the results.
A year later, Saal, Saal & Herzog (1990) found that all patients treated non-operatively for lumbar intervertebral disc extrusions had resolution of their back and leg pain with 93% having a reduction in the size of the extruded disc material. Although there was a good criteria for the diagnosis of herniated disc with associated radiculopathy, the study, unfortunately had a poor design. A very low sample size (11 patients, non-randomised); a range of 8-77 months between inception and follow up, no control group, no specificity of any treatment (i.e. There may have been conservative treatment given or no treatment at all) and non-specific outcome measures were amongst a few of its downfalls. Hence the conclusions were unreliable.
Comparisons of three different physiotherapy modalities were investigated in a high quality study by Unlu et al (2008). They concluded that lumbar traction, ultrasound and low power laser (LPL) all significantly improved physical examination findings, pain and disability scores for patients suffering acute pain from lumbar disc herniation. In this prospective, randomised design; sensitive and valid outcome measures were used to measure the effectiveness of treatment. Physical examination included lateral flexion and the Schober test to evaluate range of motion. Tenderness of the paravertebral muscles were graded for pain and the straight leg raise test (SLR) used for clinical assessment. The visual analogue scale (VAS) was used to measure pain, while Roland (RDQ) and Modified Oswestry (MODQ) disability questionnaires were used for functional evaluation, both these scales are the most commonly used for assessing disability in people with low back pain (LBP)(Beurskens, de Vet & Koke 1995).
Magnetic resonance imaging (MRI) read by blinded, highly experienced radiologists assessed the size and extent of the herniation before during and after treatment. Robust statistical analysis strengthened this study, which gave in depth reasoning for use of specific tests applied to the data. They found no overall, significant differences between treatment modalities, indicating they were all equal in there effect. These results may have been more reliable with the inclusion of a control group but as mentioned in the paper this was not possible due to ethical constraints.
Effects of lumbar traction have also been investigated by Ozturk et al (2006). A good study design compared the effects of regular physiotherapy treatment to regular physiotherapy treatment with additional traction. Outcome measures used were valid but may have been improved with the inclusion of a measure of functionality. This may not have been included as the paper states that the patients were selected from a hospitalised population but gives no indication of length of stay. Fifteen consecutive weekly physiotherapy treatments were given with computed tomography (CT) scan’s before and after the treatment period. It was found that the treatment group had a significant decrease in size of disc herniation compared to the control group, there were also significant improvements in symptoms of sciatica, SLR test and degree of motor deficit. However, presence of low back pain (LBP), motor & sensory deficits and improvements in VAS scores did not show any significant difference between treatment groups. Overall, a good quality study, implications for practice showed continuous lumber traction to be beneficial to patients with lumbar disc herniation and should be used as a form of conservative treatment to reduce the size of herniated disc material.
Use of the fear avoidance beliefs questionnaire (FABQ) gave greater dimension to a prospective, observational, cohort study, performed by Murphy, Hurwitz & McGovern (2009). They investigated the efficacy of a non surgical approach for the treatment of lumbar radiculopathy from disc herniation based on a newly formulated ‘Diagnosis Based Clinical Decision Rule’ (Murphy DR & Hurwitz EL 2007). The results of a sample of 60 patients showed significant improvements in pain (Numerical Rating Scale, NRS) (79%) and disability scores (Bournemouth Disability Questionnaire, BDQ) (70%), which were both linked with improvements in FABQ scores. Modalities used for treatment included end range loading maneuvers, distraction manipulation, neurodynamic techniques, joint manipulation and myofascial techniques. Limitations of the study were clearly and unbiasedly described, highlighted were the facts that there wasn’t complete follow up data available for all patients, a single practice setting was used which limited the generalisability of the results. The multimodal approach of the treatments prevented the identification of a single modality being superior to any of the others, due to it’s pragmatic approach. Interestingly, this also served as a strength to the study as it represented the course of treatment which would normally take place in a clinical setting as opposed to an experimental setting, giving ‘real world’ outcomes.
A very promising, large, multi-centre, randomised control trial (RTC) conducted by Weinstein et al (2006) failed to conclude on any benefit of conservative versus surgical treatment for lumbar disc herniation. A high crossover rate between groups limited the findings of this research which also gave a very poor description of physiotherapy practices used in 67% of the patients undergoing conservative treatment. It was also let down by the criteria which only included patients which had seen no benefit from 6 weeks of non surgical care, so patients showing improvement within this time were not included.
Gudavalli et al (2006) demonstrated meaningful improvements in perceived pain (VAS), function (RDI) and health status (SF-36) after 4 weeks of treatment (2-4 times p/w) with either flexion distraction (FD) by suitably qualified chiropractors or a set regime of active trunk exercise protocol (AETP) by licensed physiotherapists. The study was for chronic LBP sufferers and aimed to identify areas which have been ignored in previous study’s such as patient sub-groups, pain classification and specification of treatments. This included a subdivision of those with or without radiculopathy. Those with radiculopathy were treated with McKenzie approach extension exercises and it was found that radiculopathy patients had a better response to FD. However, sub-group sample size was small; approximately 20% of original sample size and additional modalities of ultrasound and cryotherapy were given to both treatment groups, reducing the reliability of the results. Patients were not blinded to treatment options which may have increased bias, dependent upon them having a preference for a particular intervention.
The McKenzie approach has also been investigated by Al Abdulwahaba & Al-Jabr (2008) who investigated the effect of ‘repeated back extension exercises’ on the H-reflex of patients with lumbosacral radiculopathy. H-reflex was the main outcome measure used with NRS for pain and the sit to stand test used for functionality. They used the non-involved leg as a control for measuring the H-reflex and found there was no significant difference after treatment in any of the above outcomes. However, there was only a single treatment session, which may not have been enough to provide substantial results. A longer treatment program may have been more beneficial.
Acupuncture has been shown to give better outcomes when compared to oral administration of Nimesulide and point injection of Anisodamine for the treatment of sciatica in a study by Mei-ren et al (2009). The sample size of 90 showed no evidence of justification and with outcome measures being very poorly described and much questionable theory in the discussion, the study was let down in its quality and validity.
Another study looking into the effects of acupuncture on LBP and lower limb symptoms (Inoue 2008) suggested acupuncture provided a certain degree of symptom relief but there were no details of inclusion and exclusion criteria mentioned and only two outcome measures used; VAS & continuous walking distance, the latter of which was self reported by patients. This, reduced the quality of the study and reliability of the results.
In another complementary therapy study by He et al (2006) found that the use of herbal, magnetic corsets on patients with lumbar disc herniation had positive outcomes with regard to pain (VAS) and lumbar function (Lumbar disease grade). Both control and treatment groups were given lumbar traction, electrotherapy and massage as additional treatments. The study was let down by a small sample number, patients and researchers who were not blinded and no long term follow up (only 2,3 and 4 weeks). The study may have been strengthened by the addition of a sham corset in the control group as it was noted bias may have been increased by those wearing the corset association it with a beneficial effect.
A paucity of strong research to support modalities of conservative treatment for lumbar radiculopathy has previously been attributed to clinical heterogeneity identified within trials and their participants (Hahne & Ford et al 2010), this was evident during the literature search, as differences in treatment modalities, patient selection process and use of outcome measures prevented direct comparison of one study to another.
Current guidelines for treatment of lumbar radiculopathy indicate that conservative treatment should be pursued before surgical intervention if there is no evidence of progressing neurological symptoms or possibility of cauda equina syndrome. However there is a lack of substantial evidence to suggest that conservative has any benefit over the natural history of the condition (Rhee, Schaufele & Abdu 2006).
There is no conclusive evidence that specific treatment modalities have any superioriority over others within the scope of physiotherapy (Luijsterburg 2007). The evidence base is weak regarding the efficacy of treatment interventions in general. One of the higher quality studies reviewed (Unlu et al 2008) did demonstrate improvements in pain and function but failed to identify a preferred treatment modality out of the three tested.
Problems noted with studies of this nature include the lack of control groups within most studies, this is mainly due to ethical constraints but makes it hard to evaluate the differences of improvements from intervention vs the natural history of the condition. This also appears to be an issue in studies comparing surgical to non-surgical interventions as the non-surgical intervention group could essentially be viewed as a control group with additional conservative treatments.
Large, multi-centre, RCT’s should in theory be more reliable, and generalisable to the population as a whole (i.e. If looking at a national situation such as disc herniation), however, problems with consistency of treatment and inter-rater reliability may reduce the reliability between different centers and therapists (Weinstein et al 2006). In spite of this, multi-centre trials do give the opportunity for greater sub-group analysis as discussed by Gudavalli et al (2006).
Future research in this area should include suitable sample sizes, appropriate outcome measures, inclusive of severity of pain, function and health status to back up current findings and increase reliability and validity.
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