An interbody fusion cage (colloquially known as a "spine cage") is a prosthesis used in spinal fusion procedures to maintain foraminal height and decompression. They are cylindrical or square-shaped devices, and usually threaded. There are several varieties: the Harms cage, Ray cage, Pyramesh cage, InterFix cage, and lordotic LT cage, all of which are made from titanium; the Brantigan cage, made from carbon fibre; and the Cortical Bone Dowel, which is cut from allograft femur. The cages can be packed with autologous bone material in order to promote arthrodesis. Such implants are inserted when the space between the spinal discs is distracted, such that the implant, when threaded, is compressed like a screw. Unthreaded implants, such as the Harms and Pyramesh cages have teeth along both surfaces that bite into the end plates.
Technology: expansion vs. static devices Expandable implant devices are at the forefront of technology in this field, with cages that expand in place for optimal end-plate-to-endplate fit and correction of lordosis. There are several technologies for cage expansion; FLXfit by Expanding Orthopedics offers a unique and patented 3D articulation and lordotic expansion, Staxx by Spinewave stacks plates as risers, Varilift by Wenzel - uses a screw device for enlargement and AccuLIF by CoAlign, which has a unique locking hydraulic solution for precise expansion. FlareHawk by Integrity Implants uses stent-like technology, expanding in width, height, and lordosis.
Once placed, the cages resist flexion and extension of the spine, and axial forces across the ventral and middle columns.
Further reading
- Paul C. McAfee (1999). "Current Concepts Review — Interbody Fusion Cages in Reconstructive Operations on the Spine". The Journal of Bone and Joint Surgery. American Volume. The Journal of Bone and Joint Surgery, Inc. 81 (6): 859–880. doi:10.2106/00004623-199906000-00014. PMID 10391552.
- Thomas A. Zdeblick; Alexander J. Ghanayem; Andrew J. Rapoff; Carol Swain; Tim Bassett; Mary E. Cooke; Mark Markel (1988-04-01). "Cervical Interbody Fusion Cages: An Animal Model With and Without Bone Morphogenetic Protein". Spine. Lippincott-Raven. 23 (7): 758–765. doi:10.1097/00007632-199804010-00002. PMID 9563105. S2CID 24476957.
- Branko Prpa; Melvin D. Whitfield; Isador H. Lieberman (2005). "Lumbar Interbody Cages". In Edward C. Benzel (ed.). Spine surgery: techniques, complication, avoidance, and management. Vol. 2 (2nd ed.). Gulf Professional Publishing. pp. 489 et seq. ISBN 978-9997639431.
- Robert P. Melcher; Michael Ruf; Jürgen Harms (2005). "Harms Cage". In Daniel H. Kim; Alexander R. Vaccaro; Richard G. Fessler (eds.). Spinal instrumentation: surgical techniques. Thieme. pp. 738 et seq. ISBN 978-1-58890-375-4.
- Frank Kandziora; Robert Pflugmacher; Jan Schäfer; Christian Born; Georg Duda; Norbert P. Haas; Thomas Mittlmeier (2001-09-01). "Biomechanical Comparison of Cervical Spine Interbody Fusion Cages". Spine. Lippincott Williams & Wilkins. 26 (17): 1850–1857. doi:10.1097/00007632-200109010-00007. PMID 11568693. S2CID 35417146.
- Michael Ruf; Dieter Stoltze; Harry R. Merk; Michael Ames; Jürgen Harms (2007-04-20). "Treatment of Vertebral Osteomyelitis by Radical Debridement and Stabilization Using Titanium Mesh Cages". Spine. Lippincott Williams & Wilkins. 32 (9): E275–E280. doi:10.1097/01.brs.0000261034.83395.7f. PMID 17450059.
- Sasidhar Vadapalli; Matt Robon; Ashok Biyani; Koichi Sairyo; Ashutosh Khandha; Vijay K. Goel (2006-09-01). "Effect of Lumbar Interbody Cage Geometry on Construct Stability: A Cadaveric Study". Spine. Lippincott Williams & Wilkins. 31 (19): 2189–2194. doi:10.1097/01.brs.0000232720.23748.ce. PMID 16946652. S2CID 19511678.
- Stephen T. Onesti; Ely Ashkenazi (January 2008). "The Ray Threaded Fusion Cage for Posterior Lumbar Interbody Fusion". Neurosurgery. Congress of Neurological Surgeons. 42 (1): 200–205. doi:10.1097/00006123-199801000-00046. PMID 9442526.
- Kenneth M. C. Cheung; John C.Y. Leong (2004). "Spinal Instrumentation Overview in Lumbar Degenerative Disorders: Cages". In Harry N. Herkowitz; Gordon R Bell (eds.). The lumbar spine (3rd ed.). Lippincott Williams & Wilkins. pp. 286 et seq. ISBN 978-0-7817-4297-9.
- Vijay K. Goel; Manohar M. Panjabi; Huroshi Kuroki; Setti S. Rengachary; D. McGowan; N. Ebraheim (2004). "Spinal Instrumentation". In Harry N. Herkowitz; Gordon R Bell (eds.). The lumbar spine (3rd ed.). Lippincott Williams & Wilkins. pp. 59 et seq. ISBN 978-0-7817-4297-9.
- Darrel S. Brodke; Jeffrey C. Dick; David N. Kunz; Ronald McCabe; Thomas A. Zdeblick (1997-01-01). "Posterior Lumbar Interbody Fusion: A Biomechanical Comparison, Including a New Threaded Cage". Spine. Lippincott-Raven. 22 (1): 26–31. doi:10.1097/00007632-199701010-00005. PMID 9122778. S2CID 21009248.
- J. W. Brantigan; A. D. Steffee; J. M. Geiger (June 1991). "A carbon fiber implant to aid interbody lumbar fusion. Mechanical testing". Spine. Lippincott-Raven. 16 (6S): S277–S282. doi:10.1097/00007632-199106001-00020. PMID 1862425.
- J. W. Brantigan; A. D. Steffee (1993-10-15). "A carbon fiber implant to aid interbody lumbar fusion. Two-year clinical results in the first 26 patients". Spine. Lippincott-Raven. 18 (14): 2106–2107. doi:10.1097/00007632-199310001-00030. PMID 8272967.