Background Data: Incidence of sacroiliac dysfunction in a population suffering from low back pain (LBP) after lumbosacral (LS) fusion is unknown. The underlying pathophysiology of SIJ pain may be increased by mechanical load, iliac crest bone grafting, or a misdiagnosis of SIJ syndrome. Purpose: To evaluate the incidence of SIJ pain and the accuracy of diagnostic
tools with utility of different therapeutic modalities after lumbosacral fusion. Study design: Prospective Cohort study.
Patients and Methods: We prospectively studied all the patients operated with postero-lateral fusion for the incidence and management of pain originating from SIJ joint in Neurosurgery Department, Sohag University between December 2011 and December 2015. The total number of patients was 205 patients. Indications, levels, techniques of fusion, and
Postoperative course (improvement of symptoms, and complications such as infection, peudoarthrosis, metal failure, adjacent segment diseases) all were assessed. Inclusion and exclusion parameters were selected. In addition two
management modalities were addressed. Results: Out of 205 patients, 21 patients (10%) missed in follow up, 117 patients (57%) revealed complete clinical improvement in their manifestations, while 67 patients (32.6%) revealed postoperative pain. 67 patients (32.6%) revealed postoperative pain, (low back pain only in 12 patients 20%, lower
limb pain only in 9 patients 13.5%, and both in 46 patients 66.5%).44 patients who form the basis for this report. Nine patients (20.5%) improved by medical treatment. Thirty-five patients (79.5%) improved by local injection of glucocorticoids, and local anesthetic.  Conclusion: SLJ pain should be considered at any patient developed low back pain below the waist and gluteal pain with or without nonspecific leg or groin pain in patients after lumbosacral fusion.(2016ESJ105)