Spinal fusion

Spinal fusion
Intervention
An anterior-posterior X-ray of a case of adolescent idiopathic scoliosis post-fusion
ICD-9-CM	81.0
MeSH	D013123

Spinal fusion, also known as spondylodesis or spondylosyndesis, is a surgical technique used to join two or more vertebrae. Supplementary bone tissue, either from the patient (autograft) or a donor (allograft), is used in conjunction with the body's natural bone growth (osteoblastic) processes to fuse the vertebrae.

Fusing of the spine is used primarily to eliminate the pain caused by abnormal motion of the vertebrae by immobilizing the faulty vertebrae themselves, which is usually caused by degenerative conditions. However, spinal fusion is also the preferred way to treat most spinal deformities, specifically scoliosis and kyphosis.

Reasons for spinal fusion

Spinal fusion is done most commonly in the lumbar region of the spine, but it is also used to treat cervical and thoracic problems. The indications for lumbar spinal fusion are controversial.^[1] People rarely have problems with the thoracic spine because there is little normal motion in the thoracic spine. Spinal fusion in the thoracic region is most often associated with spinal deformities, such as scoliosis and kyphosis.

Patients requiring spinal fusion have either neurological deficits or severe pain which has not responded to conservative treatment.

Conditions where spinal fusion may be considered:

• degenerative disc disease
• spinal disc herniation
• discogenic pain
• spinal tumor
• vertebral fracture
• scoliosis
• kyphosis (i.e, Scheuermann's disease)
• spondylolisthesis
• spondylosis
• Posterior Rami Syndrome
• other degenerative spinal conditions
• any condition that causes instability of the spine

Types of spinal fusion

There are two main types of lumbar spinal fusion, which may be used in conjunction with each other:

Posterolateral fusion places the bone graft between the transverse processes in the back of the spine. These vertebrae are then fixed in place with screws and/or wire through the pedicles of each vertebra attaching to a metal rod on each side of the vertebrae.

Interbody fusion places the bone graft between the vertebra in the area usually occupied by the intervertebral disc. In preparation for the spinal fusion, the disc is removed entirely, for example in ACDF. A device may be placed between the vertebra to maintain spine alignment and disc height. The intervertebral device may be made from either plastic or titanium. The fusion then occurs between the endplates of the vertebrae. Using both types of fusion is known as 360-degree fusion. Fusion rates are higher with interbody fusion. Three types of interbody fusion are:

• Anterior lumbar interbody fusion (ALIF)- the disc is accessed from an anterior abdominal incision
• Posterior lumbar interbody fusion (PLIF) - the disc is accessed from a posterior incision
• Transforaminal lumbar interbody fusion (TLIF) - the disc is accessed from a posterior incision on one side of the spine

In most cases, the fusion is augmented by a process called fixation, meaning the placement of metallic screws (pedicle screws often made from titanium), rods or plates, or cages to stabilize the vertebra to facilitate bone fusion. The fusion process typically takes 6–12 months after surgery. During this time external bracing (orthotics) may be required. External factors such as smoking, osteoporosis, certain medications, and heavy activity can prolong or even prevent the fusion process. If fusion does not occur, patients may require reoperation.

Some newer technologies are being introduced which avoid fusion and preserve spinal motion. Such procedures, such as artificial disc replacement, are being offered as alternatives to fusion, but have not yet been adopted on a widespread basis in the US. Their advantage over fusion has not been well established. Minimally invasive techniques have also been introduced to reduce complications and recovery time for lumbar spinal fusion.

References

1. ^ "Low Back Disorders (revised 2007)". Occupational Medicine Practice Guidelines (2 ed.). American College of Occupational and Environmental Medicine. 2007. p. 210. 

Further reading

• Boatright, K. Craig; Boden, Scott D. (17 February 2005). "Chapter 12: Biology of Spine Fusion". In Lieberman, Jay R.; Friedlaender, Gary E. Bone Regeneration and Repair. Totowa, New Jersey: Humana Press. pp. 225–239. doi:10.1385/1-59259-863-3:225. ISBN 9780896038479. 
• Holmes, CF, Hershman, EB, McCance, SE (May, 2005). "Chapter 9: Cervical Spine Injuries". In Schenck, RF; AAOS. Athletic training in sports medicine. Jones & Bartlett Publishers. pp.197-218. ISBN 0892031727
• Camillo, Francis X. (12 December 2007). "Chapter 36: Arthrodesis of the Spine". In Canale, S. Terry; Beaty, James H. Campbell's Operative Orthopaedics. 2 (11th ed.). Philadelphia: Mosby. pp. 1851–1874. ISBN 9780323033299. 
• Williams, Keith D.; Park, Ashley L. (12 December 2007). "Chapter 39: Lower Back Pain and Disorders of Intervertebral Discs". In Canale, S. Terry; Beaty, James H. Campbell's Operative Orthopaedics. 2 (11th ed.). Philadelphia: Mosby. pp. 2159–2224. ISBN 9780323033299. 
• Weyreuther, Martin; Heyde; Westphal, Michael et al., eds (31 October 2006). "Chapter 7: The Postoperative Spine". MRI Atlas Orthopedics and Neurosurgery The Spine. trans. Bettina Herwig. Berlin: Springer-Verlag. pp. 273–288. doi:10.1007/978-3-540-33534-4_7. ISBN 9783540335337. 
• Tehranzadehlow, Jamshid; Ton, Jimmy D.; Rosen, Charles D. (April 2005). "Advances in spinal fusion". Seminars in Ultrasound, CT, and MRI 26 (2): 103–113. doi:10.1053/j.sult.2005.02.007. ISSN 0887-2171. 
• Resnick, Daniel K.; Haid, Jr., Regis W.; Wang, Jeffrey C., eds (2 September 2008). Surgical management of low back pain (2nd ed.). Rolling Meadows, Illinois: American Association of Neurosurgeons. ISBN 9781604060355. 
• Wheeless III, Clifford Roberts; Nunley II, James A.; Urbaniak, James R., eds. "Fusion of the Spine". Wheeless' Textbook of Orthopaedics. http://www.wheelessonline.com/ortho/fusion_of_the_spine. Retrieved 3 February 2010. 

External links

• "Spinal Fusion". American Academy of Orthopaedic Surgeons. September 2007. http://orthoinfo.aaos.org/topic.cfm?topic=A00348. Retrieved 10 February 2010. 
• Spinasanta, Susan (8 August 2000). "What is Spinal Instrumentation and Spinal Fusion?". Fort Myers, Florida: SpineUniverse. http://www.spineuniverse.com/treatments/surgery/what-spinal-instrumentation-spinal-fusion. Retrieved 10 February 2010. 
• "Spinal fusion". Encyclopedia of Surgery. http://www.surgeryencyclopedia.com/Pa-St/Spinal-Fusion.html. Retrieved 10 February 2010. 
• "Degenerative Disease of the Lumbar Spine". Neurosurgical FOCUS. American Association of Neurosurgeons. March 2006. http://thejns.org/toc/foc/20/3. Retrieved 10 February 2010.