Pseudo-Pedicle Heterotopic Ossification From Use of Recombinant Human Bone Morphogenetic Protein 2 (rhBMP-2) in Transforaminal Lumbar Interbody Fusion Cages
Authors’ Disclosure Statement: The authors report no actual or potential conflict of interest in relation to this article.
Dr. Rosen and Dr. Kiester are Clinical Professors, Department of Orthopaedic Surgery, University of California Irvine School of Medicine, Orange, California. Dr. Lee is Senior Research Career Scientist, Veterans Affairs Rehabilitation Research and Development, Professor and Vice Chairman for Research and Academic Affairs, Department of Orthopaedic Surgery, and Professor, Department of Biomedical Engineering, Henry Samueli School of Engineering, University of California Irvine, Orange, California.
Address correspondence to: Charles D. Rosen, MD, Department of Orthopaedic Surgery, University of California Irvine (UCI) Medical Center, 101 City Drive S, Pavilion III, Orange, CA 92868 (tel, 714-456-1699; email, crosen@uci.edu).
Charles D. Rosen, MD P. Douglas Kiester, MD Thay Q. Lee, PhD . Pseudo-Pedicle Heterotopic Ossification From Use of Recombinant Human Bone Morphogenetic Protein 2 (rhBMP-2) in Transforaminal Lumbar Interbody Fusion Cages. Am J Orthop. January 29, 2018
TAKE-HOME POINTS
Use of rhBMP-2 in TLIF cages can result in HO out of the cage into the spinal canal.
HO from rhBMP-2 in TLIF cages can result in a radiculopathy from compression or inflammatory reaction.
HO out of the cage into the spinal canal resulting from use of rhBMP-2 in TLIF cages can be adequately diagnosed only with CT.
HO can appear as a pedicle or pseudo-pedicle.
Consider potential HO when using rhBMP-2 in TLIF cages.
References
ABSTRACT
We conducted a study to determine the common characteristics of patients who developed radiculopathy symptoms and corresponding heterotopic ossification (HO) from transforaminal lumbar interbody fusions (TLIF) using recombinant human bone morphogenetic protein 2 (rhBMP-2). HO can arise from a disk space with rhBMP-2 use in TLIF. Formation of bone around nerve roots or the thecal sac can cause a radiculopathy with a consistent pattern of symptoms.
We identified 38 patients (26 males, 12 females) with a mean (SD) age of 50.8 (7.5) years who developed radiculopathy symptoms and corresponding HO from TLIF with rhBMP-2 in the disk space between 2002 and 2015. To document this complication and improve its recognition, we recorded common patterns of symptom development and radiologic findings: specifically, time from implantation of rhBMP-2 to symptom development, consistency with side of TLIF placement, and radiologic findings.
Radicular pain generally developed a mean (SD) of 3.8 (1.0) months after TLIF with rhBMP-2. Development of radiculopathy symptoms corresponded to consistent “pseudo-pedicle”-like HO. In all 38 patients, HO arising from the annulotomy site showed a distinct pseudo-pedicle pattern encompassing nerve roots and the thecal sac. In addition, development of radiculopathy symptoms and corresponding HO appear to be independent of amount of rhBMP-2. HO resulting from TLIF with rhBMP-2 in the disk space is a pain generator and a recognizable complication that can be diagnosed by assessment of symptoms and computed tomography characteristics.
