INTRODUCTION:We report a case of acute tetraplegia, without any trauma or symptoms prior to onset, who presented with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine with concomitant spinal cord infarction. CASE PRESENTATION: A 64-year-old man with a number of risk factors for vascular disease was admitted to our hospital with progressive motor weakness in the bilateral upper and lower extremities. He had initially felt numbness in his left upper extremity and had no previous neurological symptoms or trauma. The night after the initial symptoms, he developed spastic tetraplegia requiring respiratory support. Computed tomography images of the cervical spine demonstrated the segmental type of OPLL. Spinal cord compression and signal intensity changes were identified at the level of C3/4 on magnetic resonance imaging (MRI). He underwent emergency surgery consisting of posterior decompression with laminoplasty of C3-6. Despite the surgery, the patient's tetraplegia did not improve and he continued to require respirator support. There was still no improvement in his neurological status at 10 days postoperatively, and MRI demonstrated evidence of marked spinal cord infarction. DISCUSSION: Mechanical compression of spinal arteries by OPLL and pre-existing vascular compromise had a role in the pathogenesis of spinal cord infarction. Chronic spinal compression may be characterized by 3 important factors, namely an uncommonly devastating clinical course, vascular risk factors and persistent findings on MRI, and these might lead to early diagnosis of spinal cord infarction.

Background We developed a mobile device application and dedicated pelvic positioner with the aim of improving the acetabular cup placement accuracy in patients undergoing total hip arthroplasty (THA). The function of the application was to display the intra-operative cup angle. The accuracy and clinical usefulness of this combined method were verified through comparison with the conventional alignment guide method. Methods In total, 60 patients who underwent cementless THA were included in this study. We compared the cup alignment when using this combined method with that when using the conventional alignment guide method. The absolute value error between the intra- and post-operative angles of inclination and anteversion of the cup was calculated. Results The absolute value error of inclination was 2.4° ± 2.1° in the study group and 4.0° ± 3.3° in the control group (P = 0.107). The absolute value error of anteversion was 2.8° ± 2.6° in the study group and 7.4° ± 5.3° in the control group (P < 0.001). Conclusion Using the application and pelvic positioner is simple and can be introduced at a low cost. The more accurate measurement of the intra-operative cup angle using this combined method has improved the cup insertion accuracy compared with that of the conventional alignment guide method.