In Reply: We agree with Dr Berkman that our
study design permitted only an evaluation of the short-term benefits of PENS
therapy in this population with chronic LBP. Clearly, there is a need for
further studies evaluating the long-term effects of PENS when used as part
of a multimodal rehabilitation program, which should include more effective
exercise therapy.
Although the study group was relatively young, mean (SD) age 43 [19]
years, the ages of the patients ranged from 21 to 80 years. Many younger patients
had undergone previous back surgery and were diagnosed as having "failed back
surgery syndrome." Subsequently, we have studied a variety of other chronic
pain patient populations (including sciatica, cervical neck pain, headaches,
cancer pain, diabetic peripheral neuropathic pain),1- 5
and have found results similar to those reported in our JAMA article.