BACKGROUND There is a growing interest in patient-related outcome measurement. In this field questionnaires on touch screens are becoming more common. This study was designed to identify problems in usability and feasibility of a web-based questionnaire. STUDY PARTICIPANTS AND METHODS Patients who underwent a lumbar infiltration were recruited in 5 centers and 50 patients participated of which half were older than 62 years. One third of the patients had basically no former experience with computers or touch screens. The outcome was assessed before treatment and during follow-up on a simple web-based patient questionnaire, the Activity Index. Results were presented graphically and discussed during consultation. Patients, nurses and doctors were asked for standardized feedback. RESULTS Of the patients 84% completed the questionnaire in up to 6 min. An adapted form of the system usability scale (SUS) achieved an acceptance score of 71.8%. Problems in handling occurred mostly in older patients (>65 years). The system was scored with 72.9% and 78.5% in efficiency and handling, respectively, by the nurses. The attending physicians rated the usefulness and comprehensibility of the graphical representation of the results on average as 83.3% and both were scored neutral to positive; however, an average of 11.6% rated some aspects of the report to be suboptimal. CONCLUSION This web-based questionnaire is the first of its kind to be evaluated in everyday practice of interventional pain therapy for lumbar back pain. The vast majority of the patients were able to efficiently complete the questionnaire. The questionnaire was highly acceptable to patients, nurses and doctors. We found some usability problems but mainly in the older age group.