LAS RELACIONES COMO PRÁCTICA ESPIRITUAL

and chronic low back pain in routine general practice: a cluster randomized, controlled trial. Spine, 27(11): 1149-59.

4. Urrutia G, Burton AK, Morral A, Bonfill X, Zanoli G (2004) Neuroreflexotherapy for non-specific low-back pain. Cochrane Database Syst Rev, (2): CD003009.

C11 (D) Percutaneous electrical nerve stimulation (PENS)

Definition of the procedure

Percutaneous electrical nerve stimulation (PENS) can be described as an analgesic therapy which uses acupunture-like needle probes positioned in the soft tissues and/or muscles to stimulate peripheral sensory nerves at the dermatomal levels corresponding to the local pathology (Ghoname et al 1999a). PENS treatments may vary with respect to location, frequency and duration of the electrical stimulation.

Results of search Systematic reviews

No systematic reviews were found on the effectiveness of PENS as a treatment for chronic low back pain.

Additional RCTs

Seven RCTs were found. Four of these were randomized crossover

studies (Ghoname et al 1999a, Ghoname et al 1999b, Hamza et al 1999, White et al 2001) and the other three were parallel group RCTs (Hsieh and Lee 2002, Weiner et al 2003, Yokoyama et al 2004).

Three of the randomized crossover studies examined the effects of different

treatment durations (Hamza et al 1999), different frequencies of electrical stimulation (Ghoname et al 1999b), and different montages (i.e. patterns of stimulation) (White et al 2001). The fourth one compared PENS with TENS and with flexion-extension exercises (Ghoname et al 1999a). The three parallel group RCTs compared the effects of PENS with TENS (Yokoyama et al 2004), one-shot PENS with

TENS (Hsieh and Lee 2002) and PENS plus physical therapy with sham-PENS plus physical therapy (Weiner et al 2003).

Quality assessment of the evidence

One RCT was rated as high quality (Weiner et al 2003), and the others as low quality (Ghoname et al 1999a, Ghoname et al 1999b, Hamza et al 1999, Hsieh and Lee 2002, White et al 2001, Yokoyama et al 2004).

Effectiveness

Effectiveness of PENS vs sham/placebo procedures

One high quality RCT (Weiner et al 2003) and three low quality randomised cross- over studies (Ghoname et al 1999a, Ghoname et al 1999b, Hamza et al 1999) made a comparison of the effects of PENS and sham-PENS. The three studies showed significant effects on pain in favour of PENS compared with sham-PENS. The study population of the high quality RCT (Weiner et al 2003) consisted of adults aged 65 years and older, which somewhat limits the generalisability of the results to other populations and settings.

There is moderate evidence that PENS is more effective than sham PENS in the treatment of chronic low back pain (level B).

Effectiveness of PENS vs. other treatments

Three low quality studies compared PENS with TENS (Ghoname et al 1999a, Hsieh and Lee 2002, Yokoyama et al 2004). One study showed that PENS was significantly more effective for pain relief than TENS (Yokoyama et al 2004). Another compared one-shot treatment of PENS plus medication with one-shot treatment TENS plus medication and found no differences in effects (Hsieh and Lee 2002). The third compared PENS with TENS and with flexion-extension exercises and showed that PENS was significantly more effective in decreasing pain than either TENS or flexion-extension exercises (Ghoname et al 1999a).

There is conflicting evidence that PENS is more effective than other treatments in the treatment of chronic low back pain (level C).

Relative effectiveness of different modes of PENS application (duration, frequency, location)

Three low quality randomised cross-over studies compared differing modes of PENS application. One study compared electrical stimulation for four different time intervals (0, 15, 30 and 45 minutes) (Hamza et al 1999). The 30-minute and 45-minute

durations of electrical stimulation produced similar hypoalgesic effects and were significantly more effective than either the 15-minute or 0-minute durations of electrical stimulation. Another study compared the use of different frequencies of PENS applied for 30 minutes, three times a week for 2 weeks: 4 Hz, alternating 15 Hz and 30 Hz, 100 Hz and sham-PENS (0 Hz) (Ghoname et al 1999b). Alternating 15 Hz and 30 Hz was the most effective PENS frequency for the reduction of pain. The third study compared PENS treatments with four different patterns of stimulation (montages) (White et al 2001). In all groups, patients received 30 minutes’ PENS treatment with an alternating stimulation frequency of 15 and 30 Hz, which was applied three times a week for 2 consecutive weeks. The study showed that stimulation of the lower back and buttock along the involved nerve roots at the dermatomal levels corresponding to the patients’ pain symptoms was more effective than stimulation at locations closer to the spinal column.

There is conflicting evidence that PENS treatments with 30 minutes stimulation duration, with an alternating frequency of 15 and 30 Hz, and with needle probes positioned along the involved nerve roots at dermatomal levels corresponding to the patients’ pain symptoms are more effective than PENS treatments with other treatment characteristics (level C).

Cost-effectiveness

Unknown (no studies were found on this issue)

Safety

Potential side effects for PENS are fainting, bleeding, wound infection, or even pneumothorax (Hsieh and Lee 2002). It is not clear how often these side effects occur as a result of PENS treatments. For obvious reasons PENS should preferably be applied by skilled and experienced physicians.

Subjects (indications)

Symptomatic pain relief in patients with non-specific low back pain.

Summary of evidence

• There is moderate evidence that PENS is more effective than sham PENS in the treatment of chronic low back pain (level B).

• There is conflicting evidence that PENS is more effective than other treatments in the treatment of chronic low back pain (level C).

• There is conflicting evidence that PENS treatments with 30 minutes duration of electrical stimulation, with an alternating frequency of 15 and 30 Hz, and with needle probes positioned along the involved nerve roots at dermatomal levels corresponding to the patients’ pain symptoms are more effective than PENS treatments with other treatment characteristics (level C).

Recommendation

Consider PENS for symptomatic pain reduction in patients with chronic non-specific low back pain.

References

1. Ghoname EA, Craig WF, White PF, Ahmed HE, Hamza MA, Henderson BN, Gajraj NM, Huber PJ, Gatchel RJ (1999a) Percutaneous electrical nerve stimulation for low back pain: a randomized crossover study. Jama, 281(9): 818-23.

2. Ghoname ES, Craig WF, White PF, Ahmed HE, Hamza MA, Gajraj NM, Vakharia AS, Noe CE (1999b) The effect of stimulus frequency on the analgesic response to percutaneous electrical nerve stimulation in patients with chronic low back pain. Anesth Analg, 88(4): 841-6.

3. Hamza MA, Ghoname EA, White PF, Craig WF, Ahmed HE, Gajraj NM, Vakharia AS, Noe CE (1999) Effect of the duration of electrical stimulation on the analgesic response in patients with low back pain. Anesthesiology, 91(6): 1622-7.

4. Hsieh RL, Lee WC (2002) One-shot percutaneous electrical nerve stimulation vs. transcutaneous electrical nerve stimulation for low back pain: comparison of

therapeutic effects. Am J Phys Med Rehabil, 81(11): 838-43.

5. Weiner DK, Rudy TE, Glick RM, Boston JR, Lieber SJ, Morrow LA, Taylor S

(2003) Efficacy of percutaneous electrical nerve stimulation for the treatment of

chronic low back pain in older adults. J Am Geriatr Soc, 51(5): 599-608.

6. White PF, Ghoname EA, Ahmed HE, Hamza MA, Craig WF, Vakharia AS (2001)