Selective local anesthesia versus corticosteroid infiltration on low back pain: a randomized clinical trial

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Rev Esp Anestesiol Reanim. 2019;xxx(xx):xxx---xxx

Revista Española de Anestesiología y Reanimación www.elsevier.es/redar

ORIGINAL ARTICLE

Selective local anesthesia versus corticosteroid infiltration on low back pain: a randomized clinical trial夽 A. Valencia Moya a,∗ , R. Navarro Suay b , J.A. Fernández González a , C. Gutiérrez Ortega c , T. Panadero Useros a , C. Mestre Moreiro a a

Servicio de Neurocirugía, Hospital Central de la Defensa Gómez Ulla, Madrid, Spain Servicio de Anestesia y Reanimación, Hospital Central de la Defensa Gómez Ulla, Madrid, Spain c Servicio de Medicina Preventiva, Hospital Central de la Defensa Gómez Ulla, Madrid, Spain b

Received 25 January 2019; accepted 27 August 2019

KEYWORDS Low back pain; Spondylosis; Local anesthesia; Neural therapy

Abstract Antecedents and Objectives: Local infiltrations are second line therapy in the treatment of chronic low back pain, although their use is controversial in the literature. Our objective was to compare the effectiveness of 2 types of infiltration at the paravertebral lumbar level in two groups of patients diagnosed with low back pain: corticosteroids, and selective local anaesthetic administered using segmental neural therapy (SNT). Material and Methods: Double-blind clinical trial in 55 patients diagnosed with low back pain in the neurosurgery department of the Hospital Central de la Defensa Gómez Ulla. Patients were randomised to 2 treatment groups to receive either paravertebral injections of corticosteroids or SNT. Outcomes were measured using a visual analogue scale (VAS), the Oswestry Disability Index (ODI), the Short Form-36, and patient satisfaction at the start of treatment (baseline) and at 3 and 12 months post intervention. Results: The combined treatment group showed a statistically significant improvement in ODI at 3 months. The SNT group showed a statistically significant improvement in baseline VAS vs. VAS at 3 (1.398 cm, p = 0.001) and 12 months (0.791 cm, p = 0.007). No differences were observed in the remaining variables measured. The percentage of patients that would repeat the treatment was 81% and 83%, respectively. Conclusions: Significant pain relief was achieved with SNT, and disability improved with the combined treatment. Although clinical improvement was limited, patients were satisfied. Local infiltrations should be considered as an alternative treatment for chronic low back pain.

夽 Please cite this article as: Valencia Moya A, Navarro Suay R, Fernández González JA, Gutiérrez Ortega C, Panadero Useros T, Mestre Moreiro C. Anestesia local selectiva frente a infiltración de corticosteroides en el dolor lumbar: ensayo clínico aleatorizado. Rev Esp Anestesiol Reanim. 2019. https://doi.org/10.1016/j.redar.2019.08.005 ∗ Corresponding author. E-mail address: [email protected] (A. Valencia Moya).

2341-1929/© 2019 Published by Elsevier Espa˜ na, S.L.U. on behalf of Sociedad Espa˜ nola de Anestesiolog´ıa, Reanimaci´ on y Terap´ eutica del Dolor.

REDARE-1068; No. of Pages 7

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A. Valencia Moya et al. Clinical Trial Registration: This clinical trial was registered at the European Union Clinical Trials Register with EUDRA-CT number 2015-001146-29. © 2019 Published by Elsevier Espa˜ na, S.L.U. on behalf of Sociedad Espa˜ nola de Anestesiolog´ıa, Reanimaci´ on y Terap´ eutica del Dolor.

PALABRAS CLAVE Dolor lumbar; Espondiloartrosis; Anestesia local; Terapia neural

Anestesia local selectiva frente a infiltración de corticosteroides en el dolor lumbar: ensayo clínico aleatorizado Resumen Antecedentes y Objetivo: Las infiltraciones locales son utilizadas como segunda línea en el tratamiento del dolor lumbar crónico aunque constituyen una alternativa terapéutica controvertida en la literatura. El objetivo de este ensayo clínico fue comparar la efectividad de dos tipos de infiltraciones locales: infiltración paravertebral lumbar con corticoides y anestesia local selectiva, mediante la técnica de Terapia Neural Segmentaria (TNS); en dos grupos de pacientes diagnosticados de dolor lumbar. Material y Métodos: Se realizó un ensayo clínico a doble ciego con 55 pacientes diagnosticados de dolor lumbar en el Hospital Central de la Defensa Gómez Ulla. Los pacientes fueron aleatorizados en dos grupos de tratamiento Se realizó infiltración paravertebral con corticoides y TNS en cada grupo. Registrándose la puntuación en la Escala Visual Analógica (EVA), el Oswestry Disability Index (ODI), Short Form-36 y la satisfacción, al inicio, y a los 3 y 12 meses posteriores a la intervención. Resultados: El grupo de tratamiento combinado obtuvo una mejoría estadísticamente significativa para el ODI a los 3 meses. El grupo de TNS obtuvo una mejora estadísticamente significativa al comparar EVA inicial con la EVA a los 3 meses (1.398 cm, p = 0.001) y a los 12 meses (0.791 cm, p = 0.007). No se observaron diferencias en el resto de las variables evaluadas. El porcentaje de pacientes que repetirían el tratamiento fue de 81% y 83% respectivamente. Conclusión: Se obtuvieron resultados significativos para el alivio del dolor con TNS y la discapacidad con el tratamiento combinado. Aunque la mejoría clínica fue limitada, los pacientes estaban satisfechos. Las infiltraciones locales deben considerarse como un tratamiento alternativo para el dolor lumbar crónico. Registro de ensayos clínicos: Este ensayo clínico se registró en el registro de ensayos clínicos de la Unión Europea con el número EUDRA-CT 2015-001146-29. © 2019 Publicado por Elsevier Espa˜ na, S.L.U. en nombre de Sociedad Espa˜ nola de Anestesiolog´ıa, Reanimaci´ on y Terap´ eutica del Dolor.

Introduction The treatment of low back pain is a basic aspect of many medical specialties. This common, disabling condition occurs in most individuals at some time in their life.1,2 In most cases, the aetiology of lower back pain lasting less than 6 weeks is unknown and usually self-limiting, particularly in younger patients. Imaging studies of elderly patients often show degenerative changes, although these arthritic changes do not always correlate with symptoms.3 Several risk factors for spondyloarthrosis have been put forward,4 the most important being genetics5 and lifestyle, particularly the patient’s level of physical activity.6,7 The treatment of back pain is often complicated, due to its recurrence and the difficulty of achieving permanent remission. Treatment usually starts with analgesia, and in some cases with rehabilitation.8 In most cases, the symptoms are self-limiting, and resolve without the need for

therapeutic escalation.9 Recurrence is very common, and chronification, though less frequent, becomes a highly disabling factor in the performance of daily activities, and is one of the main causes of absenteeism.10 In patients with chronic low back pain, it is essential to explore the different underlying causes and rule out those that are potentially surgical. Degeneration of the facet joints and the intervertebral disc can result in stenosis of the compartments that contain nervous system structures, and this is an indication for spinal decompression surgery. This procedure, however, is not without risks, and the outcome is not always satisfactory.11,12 The different techniques for treating back pain have mainly been developed to relieve symptoms, even when they attempt to address the underlying causes, and are therefore a temporary solution. Few such procedures have passed the standard of scientific proof or yielded specific indications.13 The development of different anaesthetic

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Selective local anesthesia versus corticosteroid infiltration on low back pain techniques and a multitude of pharmacological therapies have led to the establishment of the different treatment strategies routinely used in pain units. Epidural infiltration in the facet joint, foramen or disc using different combinations of anaesthetic agents and corticosteroids is an alternative for difficult-to-manage, polymedicated patients that are contraindicated for surgery. One of the least known anaesthetic techniques is neural therapy, which was developed in Germany in the twentieth century and is now used in many countries.14,15 Despite its apparent simplicity - only local anaesthetics and anatomical landmarks are used to puncture different structures - the therapy has obtained very positive results. In neural therapy, local anaesthetic is injected at a particular site (segmental neural therapy) and another injection is administered at a distance, in areas called ¨interference fields.¨ Segmental neural therapy (SNT), which treats trigger points, muscles, and facet joints, can be considered a type of selective local anaesthesia (SLA).

Material and methods This clinical trial was included in the registry of clinical trials of the European Union with EUDRA-CT number 2015-00114629. The clinical research ethics committee of the Gómez Ulla Hospital approved the trial in July 2015, and authorisation from the Spanish Agency for Medicines and Health Products was obtained in January 2016. The main outcome measure of the study was to prove that local infiltration treatments improve pain in patients with degenerative lumbar spine pathology, reduce consumption of oral analgesics, reduce the disability associated with low back pain, and improve the patient’s self-perceived overall health status. In this double-blind clinical trial, one team of investigators recruited patients, another administered the treatment, and a third performed the evaluations. The data analysis was performed by the Preventive Medicine Service, which was not involved in the previous phases. Participants were divided into 2 treatment groups: Group 1 received combined paravertebral injection of mepivacaine, betamesona and group B vitamins; and Group 2 received SLA with procaine alone. The sample size was determined on the basis of a variation of 1.5 cm in the visual analogue scale (VAS), since this is the minimum clinically important difference (MCID) for low back pain. Accepting an alpha risk of 0.05 and a beta risk of 0.2 in a two-tailed test, 28 patients were required in each group in order to detect a difference equal to or greater than 1.5 VAS units. A standard deviation of 2 was estimated, with a follow-up loss of 0%. Patients with chronic low back pain seen in the hospital’s neurosurgery outpatient clinic between January 2016 and March 2016 were invited to take part in the study. Patients initially recruited were interviewed by investigators, and each patient that fulfilled the inclusion criteria was given an informed consent form and a study brochure. Patients treated with anti-platelet drugs or anticoagulants, with a history of allergy or adverse reactions to the study drugs, with pain secondary to acute (non-union) fractures, or diagnosed with cancer or systemic diseases were excluded from

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the study. Patients scheduled for surgery were not included. Before being assigned to a treatment group, the following forms were completed for each patient: a clinical form that included a VAS score and a description of analgesic medication; an Oswestry disability index (ODI); and a self-perceived health form (SF-36). The subject’s oral analgesic treatment prescribed prior to inclusion in the study was not standardised. To minimize the bias this could cause, we recorded and analysed the different treatments received in each group. This showed a similar prescription pattern in both groups. Patient details were anonymised using a numerical code, and each group was treated on different days. Patients were randomized to treatment groups using a random number table. The treatment used in each group was only known to the investigator in charge of administering the therapy. The investigator prepared the medication in a separate room. Before administering the study drug, patients were asked to place themselves in a prone position before the investigator entered the room, and remain in this position until the investigator had left the room. One group of investigators recruited participants, another group prepared the study drugs, another administered the treatments, and yet another group collected and analysed the data. Participants were treated in 4 separate infiltration sessions at 15-day intervals. Study subjects underwent 2 follow-up interviews, 1 took place 3 months after the start of the treatment, and the other 12 months after the first treatment session. In addition to the parameters described above, patient satisfaction with the treatment and dosage differences in the medication administered prior to the study were also collected. In the final interview, participants were asked whether they would repeat the treatment if needed. Group 1 patients were treated by a neurosurgeon with clinical experience in this technique. Patients received 4 treatment sessions; in each session 6 mg betamethasone, 10 mg mepivacaine, and 5/100/100 mg cyanocobalamin/pyridoxine/thiamine were administered, divided into 2 syringes. The drugs were administered by intramuscular injection 2 cm from the spinous processes of L3-L4. In Group 2, patients received 4 sessions of SLA performed by a neurosurgeon with previous experience. The technique consists of intradermal injections in trigger points and scars located in the lumbar area, together with injections in the paravertebral muscles and the facet joints. Facet joints injections were performed by inserting the needle 2 cm from the caudal section of the lumbar spinous processes until bone contact was made, then withdrawing the needle 1 mm before depositing the anaesthetic. The total dose administered depended on the number of injections, but never exceeded 20 mg procaine. The clinical trial concluded in June 2017, after the last follow-up interview. The measure of association between 2 categorical variables was calculated using Pearson’s ␹2 or Fisher’s exact test if both were dichotomous, in which case the effect was assessed by risk estimation (RR), and accuracy by the 95% confidence interval. The student’s t test was used to determine the correlation between a parametrically distributed (K-S) dichotomous independent variable and a dependent quantitative vari-

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A. Valencia Moya et al. Table 1

Table 2

Visual Analogue Scale (VAS).

Mean VAS score Group 1

2

N Mean Standard D N Mean Standard D

Oswestry Disability Index (ODI).

Mean ODI score VAS

3 VAS

12 VAS

Group

26 6.784 1.4956 29 6.531 1.7672

22 5.756 2.0007 24 5.133 2.0038

22 5.970 1.7780 24 5.740 1.8110

1

able, testing the effect by the difference in means, and the accuracy by the 95% confidence interval. The correlation between 2 Gaussian (K-S) quantitative variables, 1 dependent and 1 independent, was determined by linear regression, estimating the square of its regression coefficient (r2) and the equation of the corresponding line. If both were independent, the correlation was estimated using a Pearson bivariate correlation, and the corresponding correlation coefficient (r) was obtained. In all cases, significance was set at p < 0.05, and all data were analysed on SPSS® version 15.

Results

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Table 3

N Mean Standard D N Mean Standard D

ODI

3 ODI

12 ODI

26 51.344 18.2755 29 41.061 17.4376

22 36.929 17.2796 24 37.783 18.1201

22 42.195 23.2453 24 36.647 15.6316

Background treatment.

Background treatment Group

Medication

N

Percentage

1

Paracetamol NSAID Opioids Muscle relaxants Antiepileptic Paracetamol NSAID Opioids Muscle relaxants Antiepileptic

19 16 8 7 4 18 16 9 8 5

73.1 61.5 30.7 26.9 15.4 62.1 55.2 31.0 27.6 17.2

2

NSAID: non-steroidal anti-inflammatory.

Fifty-five patients were included at the start of the study. Group 1 was formed of 26 participants who received combined paravertebral infiltration. Group 2 consisted of 29 subjects treated with SLA. Nine patients were lost to followup, 4 in Group 1 and 5 in Group 2. In Group 1, two patients failed to attend the corresponding follow-up session, 1 patient could not tolerate the pain associated with the injection of local anaesthetic, and 1 patient was excluded from the study when he presented a lumbar vertebral fracture. In Group 2, one patient failed to complete follow-up, 2 patients could not tolerate the pain associated with the injection, 1 patient was excluded from the study when he underwent surgery for cervical spine arthrodesis, and 1 patient was excluded due to pregnancy. Group 1 consisted of 20 (76.9%) women and 6 men. Group 2 consisted of 22 (80%) women and 7 men. Mean age was 63 and 61 years, respectively. To determine the superiority of either treatment, the VAS scores from each group were compared at baseline, at 3 months (3 VAS) and 12 months (12 VAS); no statistically significant differences were observed. Patients in Group 2 showed an average decrease of 1.398 cm in the 3 VAS score, p = 0.001. Baseline VAS was 0.791 cm longer than 12 VAS (6.351---5.74), p = 0.007. No statistically significant differences were found between any of these variables in Group 1 (Table 1). Mean baseline ODI score was higher than Group 2. An analysis of the disability associated with low back pain showed no differences between groups. Analysing each group separately, we observed that Group 1 showed an average post-treatment reduction of 13.261 at 3 months (p < 0.001). In Group 2 the difference was not statistically significant (Table 2). The sample size was too small to com-

pare ODI scores. The inter-group differences observed in the SF-36 were not significant. The most frequent analgesic medication in Group 1was paracetamol (73%). Taking into account that patients could take more than 1 type of medication, the second most frequent medication was NSAID (61.5%). The most frequent medication in Group 2 paracetamol (62%), followed by NSAID (45%) (Table 3). At the 3-month follow-up visit, 43.4% of the 46 patients reported a reduction in their background analgesic dosage; 4.3% reported an increase in background dosage, mostly attributable to normal clinical fluctuations. Group 2 reported the highest percentage decrease (62.5% of all patients in the group) in background analgesic dose at the 3-month follow up visit (Fig. 1). Poorer outcomes were observed at the 12-month follow-up visit, when a decrease of only 30.4% was found (Fig. 1). This reduction in Group 2 was higher than in Group 1 (38.9% vs. 22.7%). Over half (59%) of patients in Group 1 were either satisfied or very satisfied, and 81.8% would repeat the treatment. Satisfaction was slightly higher in Group 2, with 62.5% of patients being satisfied or very satisfied, and 83.3% stating they would repeat the treatment. Six adverse reactions were recorded in Group 1 during the treatment period. Most were of little importance, and occurred during the first few treatment sessions. All patients were able to continue with the treatment except for 1, who presented a local allergic reaction. One case of lumbar vertebral fracture was observed during the treatment process, detected by increased pain during injection. After radiographic confirmation, the patient was withdrawn from the

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Selective local anesthesia versus corticosteroid infiltration on low back pain

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Replace by: Differences in the medication administered prior, % 100

33.3

80

50 63.6

60

72.7

40 62.5

38.9 22.7

20 22.7 13.6 0

4.5 Group 1

4.2 Group 2

Group 1

3 months

Group 2

12 months Increase

Figure 1

12.5

Decrease

No change

Dose changes in background treatment at 3 and 12 months of the intervention. Percentage of total dosage.

study. This patient presented several risk factors: woman, >60 years and obesity. In Group 2, five of the 8 adverse reactions were considered mild. Only 1 of the 3 pain reactions was considered moderate, and the patient was withdrawn from the study. In all cases, the adverse reactions resolved completely.

Discussion This study shows that both treatments obtained pain relief. However, it is important to define the minimum clinically important difference (MCID), since it allows us to correlate the variations in the measurement scales and the clinical changes perceived by our patients.16 The MCID established for low back pain (1.4 cm)17 was only achieved in the procaine treatment group at 3-month follow-up. No statistically significant differences in pain relief were observed between both treatments. A greater reduction in background analgesic consumption (in 62.5% of patients) was observed in Group 2. The combination treatment was more effective in reducing the disability associated with low back pain, and achieved a statistically significant 13-point reduction in ODI at 3 months. This reduction is above the MCID for ODI.17 Differences in self-perceived health were not significant, with neither treatment reaching the MCID. In the final evaluation, patients were asked to rate their overall satisfaction with the treatment, and whether they would be willing to repeat the therapy. The satisfaction in both groups was higher for the first period, 59% and 62% of participants in each group, respectively, were either satisfied or very satisfied. More than 80% of patients in both groups would repeat the treatment in the event of recurrence. Generally speaking, the level of recommendation for this type of treatment is low. Most studies lack long-term follow-up and randomization,18 and we found none that compare both treatments (Table 4). One study that compared intradiscal or epidural infiltration19 found better results in the epidural group. These results are comparable to our patients treated with procaine. Improvement in disability in our Group 1 was superior to both treatments.

Manchikanti20 compared facet joint treatment with local anaesthetics in 1 group, and anaesthetic plus betamethasone in another group. They observed greater relief from both pain and disability than both our groups. Two studies evaluating analgesia therapy using VAS21,22 reported similar results to those observed in our Group 2 (procaine), although VAS scores was higher and difference in ODI scores were not evaluated. A study evaluating acupuncture vs. dry puncture23 found differences between groups, and the improvement in VAS scores was superior to both our groups. Differences in disability were not evaluated. Prolotherapy compared with saline injection24 was equally effective in improving pain and disability. Table 6 shows a comparison of the evolution of VAS in our patients and in the most relevant studies. It is important to note that, based on our results and those of previous studies, the analgesic effect could be due to the mechanical effect of the puncture rather than to the substance administered. It is important to take into consideration the analgesic placebo effect that these techniques can have in chronic patients. The adverse reactions observed in our groups are comparable to those described in other similar studies.25 The vertebral fracture diagnosed in one of our patients could not be due to the study technique, since this patient had received only 1 puncture. Patients suffering from degenerative spinal diseases usually have 2 options: conservative or surgical treatment. Conservative treatment usually consists of medical therapy supplemented by rehabilitation together with lifestyle and dietary measures. Surgical treatment is offered to those patients with a risk of motor sequelae and/or persistent pain that does not respond to medication. However, other therapeutic alternatives are available for patients contraindicated for surgery who do not respond to conservative treatment. These strategies, as our study shows, are less aggressive than surgery, and can improve the quality of life of patients with spinal diseases. This study has some limitations: First, several losses occurred during follow-up; Second, previous pharmacological treatment, physical therapy and surgical treatment differed in both groups. Analgesic therapy taken after the

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A. Valencia Moya et al. Table 4

Differences in visual analogue scale (VAS) scores and comparison with the literature.

Author

Design

Group

Baseline VAS

3 VAS

12 VAS

Valencia

Clinical trial

Butterman

Cohort study

Manchikanti

Clinical trial

Lóriz Peralta Atalay

Observational Cohort study

Leibing

Clinical trial

Yelland

Clinical trial

Mauro

Clinical trial

Lilius

Clinical trial

Civelek

Cohort study

Celik

Clinical trial

Corticosteroids Neural therapy Epidural coricosteroid Intradiscal coricosteroid Facet joint bupivacaine Bupi + betamethasone Neural therapy Neural therapy Physical therapy Acupunture Dry puncture Physical therapy Prolotherapy (Glu + Lign) Saline IM vitamin B12 Placebo Facet cortisone Pariarticular cortisone Saline Facet joint radiofrequency Methylprednisolone + Bupi NSAIDs/oral relaxants Bupi / prilo + Methylpred facet joints

6.78 ± 1.4 6.63 ± 1.7 6.7 7.2 8.2 7.9 7.94 ± 1.64 7.4 ± 2.24 7.85 ± 2.28 4.8 5.3 5.4 5.19 ± 1.9 5.50 ± 2.0 7.55 ± 0.8 7.06 ± 0.7 4.55 5.10 5.20 8.20 ± 0.8 8.50 ± 0.8 7 8

5.75 ± 2 5.13 ± 2a 5.2a 6.2 3.8a 3.5a 3.74 ± 3a 3.56 ± 2.6b 4.79 ± 3.5b 2.1a 3.2a 4.4 3.5 ± 2.0a 3.8 ± 2.0a 0.9 ± 1.5b 3.68 ± 2.7 4.40a 4.20a 4.40a 2.4 ± 0.3b 1.2 ± 0.1b 4a 5a

5.97 ± 1.7 5.74 ± 1.7 4.9 6.8 3.7a 3.5a No No No No No No 3.3 ± 2.0a 3.6 ± 2.0a No No No No No 2.6 ± 0.1a 4.9 ± 0.2a No No

a b

Statistical significance. Statistical significance immediately after treatment.

study treatment also varied considerably. A cross-over clinical trial is needed to reduce possible bias and ascertain the participants’ preferred treatment.

Conclusions Treatment with SLA achieved statistically significant pain relief at 3 months. However, pain improvement did not differ significantly between groups. We observed a statistically significant reduction in disability associated with low back pain at 3 months in the group treated with combination therapy, although there were no inter-group differences in disability scores. The procaine group showed greater reduction in analgesic consumption. Patient satisfaction was greater than 50%, and more than 80% would repeat the treatment. In our experience, based on the results of this study, we can conclude that local infiltrations should be considered as a complementary treatment in patients with chronic low back pain.

Conflicts of interest The authors declare that they have no conflicts of interest.

Acknowledgements Our thanks go to all the staff of the Central Hospital de la Defensa Gómez Ulla involved in conducting this clinical trial.

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