IntroductionDisc herniation leading to nerve root displacement with compression and causing radicular symptoms is only one of a variety of possible causes of lumbar and ischiadic pain. Pain radiating into the leg is not necessarily caused by irritation of the root [18,19]; Norman and May [25] identified the sacroiliac joint (SIJ) as one of the possible starting points of such complaints via injection of local anaesthetic. Disc herniations were detected on CT and MR scans in a high percentage of asymptomatic patients [5,16,17,31,32]. Likewise it has been shown that the size of herniations does not correlate with displayed clinical symptoms [6,8, 34]. If, despite the lack of sensory or motor losses, the incidental finding of pathologic disc morphology is concluded to be the source of pain, the wrong therapy may be initiated, e.g. nucleotomy, leading to unsatisfactory postoperative results [7,[28][29][30]. This has to be considered when a choice between surgical and non-surgical treatment is made.The lack of consideration of alternatives to disc-triggered pain is encouraged by the fact that some alternative diagnoses are undetectable by imaging procedures. Functional disorders in general, and dysfunction of the SIJ in specific, cannot be detected by CT or MRI. Reversible Abstract A dysfunction of a joint is defined as a reversible functional restriction of motion presenting with hypomobility according to manual medicine terminology. The aim of our study was to evaluate the frequency and significance of sacroiliac joint (SIJ) dysfunction in patients with low back pain and sciatica and imaging-proven disc herniation. We examined the SIJs of 150 patients with low back pain and sciatica; all of these patients had herniated lumbar disks, but none of them had sensory or motor losses. Forty-six patients, hereinafter referred to as group A, were diagnosed with dysfunction of the SIJ. The remaining 104 patients, hereinafter referred to as group B, had no SIJ dysfunction. Dysfunctions were resolved with mobilizing and manipulative techniques of manual medicine. Regardless of SIJ findings, all patients received intensive physiotherapy throughout a 3-week hospitalisation. At the 3 weeks follow-up, 34 patients of group A (73.9%) reported an improvement of lumbar and ischiadic pain, 5 patients were pain free. Improvement was recorded in 57 of the group B patients (54.8%); however, nobody in group B was free of symptoms. We conclude that in the presence of lumbar and ischiadic symptoms our presented data suggest consideration of SIJ dysfunction, requiring manual medicine examination and, in the presence of SIJ dysfunction, appropriate therapy, regardless of intervertebral disc pathomorphology. This could avoid wrong indications for nucleotomy.