Efficacy of Epidural Perineural Injections With Autologous Conditioned Serum for Lumbar Radicular Compression: An Investigator-Initiated, Prospective, Double-Blind, Reference-Controlled Study

Cordelia Becker, MD; Stefan Heidersdorf, MD; Sascha Drewlo, MSc; Sonja Zirke de Rodriguez; Juergen Krämer, MD; Roland Ernst Willburger, MD

Disclosures

Spine. 2007;32(17):1803-1808. 

In This Article

Patients and Methods

This investigator-initiated study was conducted in compliance with the German Drug Law. The ethical review committee of the medical faculty at the University of Bochum approved the study protocol.

Consecutive male and female outpatients with unilateral lumbar radicular compression as a critical inclusion criterion and willing to participate were enrolled into the study. Patients provided a written informed consent. The clinical diagnosis was confirmed by magnetic resonance imaging or computerized tomography showing a herniation of the nucleus pulposus or scarring after previous surgery. Pain duration was at least 6 weeks, and pain intensity was moderate to severe.

Patients needing early surgery because of clinically remarkable pareses or unbearable pain were excluded from the study. Other critical exclusion criteria comprised additional neurologic illnesses, cervical myopathy, systemic bone or joint illnesses, previous epidural or epidural perineural injection to the affected nerve root in the last 3 months, and cortisone or opioid use in the last 6 months.

All pain medications were discontinued at the beginning of the trial; patients received no additional medical therapy or physiotherapy. At the request of the ethical review board, ibuprofen was allowed for the treatment of pain during the 6-month trial period.

The average dosage of ibuprofen was 1200 mg per day, and there was no significant different usage between the 3 groups. None of the patients had ibuprofen-induced side effects.

According to the protocol, 60 patients were to be included (20/study arm). In total, 90 patients were recruited. Patients were randomized to 1 of the 3 groups and received 3 epidural perineural injections of ACS, 10 mg triamcinolone, or 5 mg triamcinolone ( Table 1 ). The unit of randomization was the individual patient. Allocation was made by opening sequentially numbered sealed envelopes. These had been filled by a study nurse not involved in the care of the patients using a random number table. There were 2 dropouts; these patients refused further injections. Four additional patients were excluded because of missing data. A total of 84 patients were evaluated.

ACS was produced as described by Meijer et al.[8] All injections were performed under radiograph control.[9] Patients and the responsible physicians were blinded. For technical reasons, blinding was not possible for the injection procedure. This was performed by a physician not otherwise involved in the care of the study subjects.

Interventions were carried out in an orthopedic practice in close cooperation with the orthopedic department of the medical faculty (University of Bochum, Bochum, Germany). Following a run-in period of 2 weeks, necessary for the preparation of ACS, patients were injected once per week for 3 consecutive weeks (time points 1, 2, and 3). Follow-up examinations were scheduled at 6 weeks (time point 4), 10 weeks (time point 5), and 22 weeks (time point 6) following the first injection.

Before receiving the first injection and at the follow-up visits, patients documented their pain intensity using the 100 mm Visual Analogue Scale (VAS), ranging from 0 (pain free) to 100 (greatest pain intensity). This assessment was the primary endpoint of the study. The secondary endpoint was the Oswestry Disability Index (ODI) at selected time points. Both methods of assessment are well known and accepted outcome scores for low back pain.[10,11,12]

Using the epidural perineural injection with a double-needle technique, it is possible to infiltrate selective 1 nerve root. An oblique interlaminar approach with a 29-G spinal needle leads into the anterior epidural space and reaches the nerve root directly. Therefore, only a small amount of medication is necessary, in former studies 1 m3 local anesthetic plus 10 mg triamcinolone proved to be sufficient. This technique had better outcome than paravertebral injections, adverse side effects are lower than with the conventional technique, and injections can also be performed on outpatients.[9]

The injected material was 1 m3 local anesthetic plus 10 mg triamcinolone in the first group, 1 m3 local anesthetic plus 5 mg triamcinolone in the second group, and the conditioned autologous serum only in the third group, no other medications have been added.

The selection of the sample size was pragmatic for this exploratory study. All statistical analyses were performed in an exploratory manner. Statistical analysis was performed using SAS for Windows, version 8.2, on a personal computer. Descriptive statistics (n, mean, standard deviation, median, lower and upper quartiles, minimum and maximum) were calculated for the VAS and ODI score by treatment group (Groups 1-3 and the total) and time point, including the last time point with available data. Descriptive statistics were also calculated for the difference in VAS and ODI score to the first time point.

The data were submitted to a repeated-measures analysis of variance with effects on treatment group, time, and treatment group-by-time interaction. The differences between treatment groups were examined for score at time point 1, score at last time point 6, score difference last time point minus time point 1, using separate analyses of variance withtreatment group included in the model. From these analyses, 95% confidence intervals for the differences between the treatment groups were calculated. Time profiles were then analyzed per treatment group using analysis of variance with effects for subject and time included in the model. Assumptions for analysis of variance appear to hold from inspection of the data distributions and the residuals plots.

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