What are the evidence about electrical stimulation for pressure ulcer prevention and treatment in Spinal Cord Injury? – A systematic review and meta-analysis

Context: Electrical stimulation (ES) can confer benefit to pressure ulcer (PU) prevention and treatment in spinal cord injuries (SCIs). However, the clinical guidelines on ES for PU prevention in SCI are limited. New NPUAP/EPUAP clinical guideline 2014 recommends the use of ES to facilitate healing in recalcitrant stage II, any stage III and IV PU. Yet the effectiveness of different type and mode of ES for PU healing in SCI is unclear.
Objectives: To critically appraise and synthesize the research evidence on ES for PU prevention and treatment in SCI.
Method: Any types of interventional studies published from 1985 to June 2015 were included. Target population included adults with SCI. Interventions of any type of ES were accepted. Any outcome measuring effectiveness of PU prevention and treatment was included. Methodological quality was evaluated using established instruments. Pooled analyses were performed to calculate the mean difference for continuous data, odds ratio for dichotomous data.
Results: Thirty studies were included, 17/30 studies were preventive studies, 13/30 trials were therapeutic trials. Two types of ES modalities were identified in therapeutic studies (surface electrodes, anal probe). Four types of modalities in preventive studies (surface electrodes, ES shorts, sacral anterior nerve root implant, neuromuscular ES implant). ES enhanced PU healing in all 13 therapeutic studies. Pooled analyses of eight unique controlled therapeutic trials showed ES significantly improved weekly healing rate (WHR) (mean difference (MD by 22.5 (95% CI 5.27-15.73, p<0.0001). Pooled subgroup analysis of therapeutic trials showed that pulsed current ES significantly improved WHR compared with no ES 13.1, 95% CI 5.70-20.4, p=0.0005, I2=94%). Subgroup analyses of two therapeutic trials showed significantly higher numbers of ulcers healed (odds ratio (OR) 2.95, 95% CI 1.69-5.17, p=0.0002, I2=0%) with ES treatment. Subgroup analysis of three therapeutic trials showed that patients with ES treatment reported significant less number of PU worsened than control group. (OR 0.30, 95% CI 0.10–0.89, p=0.03, I2=9%).
Conclusion: The methodological quality of the studies was poor, in particular for prevention studies. The findings of ES for PU prevention in SCI are inconsistent across studies. The great variability in ES parameters, stimulating locations, and outcome measure prevent a formal meta-analysis on ES for PU prevention. ES appears to increase WHR in SCI. Pulsed current ES seems to confer better benefit on PU healing than direct current. Future research is suggested to improve the design of ES devices, standardize ES parameters alongside outcomes measures and address device-related adverse events for PU prevention studies. To confirm the beneficial effect on the enhancement of PU healing in SCI, more rigorous preclinical studies and clinical trials on determining the optimal stimulation parameters and electrodes placement are warranted.