Arterial injury following percutaneous vertebral augmentation: a case report.

STUDY DESIGN: Case report. OBJECTIVE: To report a case of injury to a segmental branch of the L4 lumbar artery following kyphoplasty. SUMMARY OF BACKGROUND DATA: To our knowledge, arterial injury following vertebral augmentation has not been described. The complications that have been reported rarely require additional intervention. The caliber of the fourth lumbar artery is such that injury to it, or to its more proximal branches, may cause significant morbidity. METHODS: An 84-year-old female who presents 10 days after surgery from L5 kyphoplasty with pulsatile bleeding from the kyphoplasty site. An angiogram revealed an injury to a segmental branch of L4 lumbar artery. RESULTS: A superselective angiogram was performed, followed by embolization of a branch of the L4 lumbar artery. This procedure successfully controlled the bleeding. CONCLUSION: Surgeons performing percutaneous procedures for the augmentation of vertebral compression fractures are not able to visualize the arterial channels on the posterior aspect of the vertebral column. Although injury to these structures may be difficult to prevent, awareness of this complication will improve our response and decrease associated morbidity.

Multiaxis muscle strength in ACL deficient and reconstructed knees: compensatory mechanism.

PURPOSE: It is unclear how muscle strength in tibial rotation and knee abduction change following anterior cruciate ligament (ACL) injury and reconstruction. Such strength changes are likely, considering the oblique orientation of the ACL and the constraint provided by the ACL at various tibial rotation and adduction positions. The purposes of this study were to evaluate multiaxis muscle strength in ACL deficient and reconstructed knees and to gain insights into potential compensatory mechanisms adopted by the patients. METHODS: Muscle strength in tibial internal-external rotation, abduction-adduction, and flexion-extension were investigated in 19 chronic ACL deficient, 18 acute ACL deficient, 21 ACL reconstructed, and 23 normal subjects. The strength ratios of flexion/extension, abduction/adduction, and internal/external rotation were determined for each subject and compared across the different populations. RESULTS: The chronic ACL deficient patients showed significantly lower strength ratio in internal/external rotation than that of the normal controls and acute ACL deficient subjects (P = 0.02), indicating a compensatory mechanism developed by the patients to unload the ACL and/or to avoid unstable knee positions. For ACL reconstructed patients, the internal/external rotation strength ratio became closer to their counterparts in normal controls than that of chronic ACL deficient patients, presumably reflecting the reduced need for compensation after reconstruction. Furthermore, compared with strength reduction in knee extension, reductions in tibial rotation and abduction strength following ACL reconstruction were less severe and more easy to recover. CONCLUSION: A better understanding of changes in multiaxis muscle strength and the associated compensatory mechanism will help us evaluate treatment outcome more accurately and develop more effective treatment modalities with focus on muscles that help protect and unload the ACL.