THE OCCURRENCE AND INTERRATER RELIABILITY OF MYOFASCIAL TRIGGER POINTS IN THE QUADRATUS LUMBORUM AND GLUTEUS MEDIUS - A PROSPECTIVE-STUDY IN NONSPECIFIC LOW-BACK-PAIN PATIENTS AND CONTROLS IN GENERAL-PRACTICE

The presence of a trigger point is essential to the myofascial pain sy ndrome. This study centres on identifying clearer criteria for the pre sence of trigger points in the quadratus lumborum and gluteus medius m uscle by investigating the occurrence and inter-rater reliability of t rigger point symptoms. Using the symptoms and signs as described by Si mons' 1990 definition and two other former sets of criteria, 61 non-sp ecific low back pain patients and 63 controls were examined in general practice by 5 observers, working in pairs. From the two major criteri a of Simons' 1990 definition only 'localized tenderness' has good disc riminative ability and inter-rater reliability (kappa > 0.5). This stu dy does not find proof for the clinical usefulness of 'referred pain', which has neither of these two abilities. The criteria 'jump sign' an d 'recognition', on the condition that localized tenderness is present , also have good discriminative ability and inter-rater reliability. T rigger points defined by the criteria found eligible in this study all ow significant distinction between non-specific low back pain patients and controls. This is not the case with trigger points defined by Sim ons' 1990 criteria. Concerning reliability there is also a significant difference between the two different criteria sets. This study sugges ts that the clinical usefulness of trigger points is increased when lo calized tenderness and the presence of either jump sign or patient's r ecognition of his pain complaint are used as criteria for the presence of trigger points in the M. quadratus lumborum and the M. gluteus med ius.