The spine is made up of segments of bones called vertebrae. Each vertebrate is connected to each other by strands of soft tissue known as ligaments, and cushioned for movement with disks in between each vertebrate. In conditions where there is large amounts of damage to vertebrate or soft tissue a spinal fusion may be recommended. In spinal fusion surgery bone is taken from the hip to create a bridge to the vertebrae next to the damaged area. Fusion can span one vertebra or multiple vertebrae.
The use of external bone growth stimulators (BGS) in spinal fusion has been shown to be an affective adjunct, meaning paired treatment, with spinal fusion surgery [1,4]. From papers involving governance of when to best use bone growth stimulators it is suggested to be appropriate when the person is at a high risk of a condition called pseudoarthrosis due to previously failed fusion surgery or in conditions that may increase the risk of nonunion fractures [1,2]. These conditions include alcoholism, diabetes, and obesity. In pseudoarthrosis the body will perceive bone fragments as separate bones and will do nothing to unite them. Because of this condition the spinal fusion will continue to fail .
Within studies it has also been defined that noninvasive bone growth stimulators can be useful in spinal fusions that are fusing vertebrate at more than one level [2, 8-10].
The devices generate a weak electrical current within the target site over the healing area using different techniques such as pulsed electromagnetic fields (PEMF), capacitive coupling (CC) and combined magnetic fields (CMF). Each technique utilizes different treatment protocols to achieve healing at the site.
CC devices use small skin pads that are placed on either side of the fusion and worn 24 hours a day until either healing occurs or up to nine months, at which time if healing does not occur the treatment is deemed ineffective . In PEMF devices the electromagnetic fields are delivered via coils either placed into a special back brace or directly on the skin. The device is used for six to eight hours a day for a period of three to six months. For CMF devices there are two types of magnetic fields utilized. The device is used for 30 minutes per day for nine months.
There have been a number of devices that have received FDA premarket approval for spinal fusion, including The SpinalPak BSG system, which is a CC device that received premarket approval in 1999 for use in lower back (lumbar) spinal fusion at one or two levels . The EBI Bone Healing system is a PEMF device that received premarket approval in 1979 for failed fusions and congenital psuedoarthroses. SpinaLogic, a CMF device, received approval status in 1994 [1, 6]. This belt device is marketed to help with spinal fusion healing rates. Lastly the newest approved device is utilized in vertebral fusion in the neck, also known as the cervical spine. The Cervical-Stim received approval in 2004 for adjunct use in cervical surgery patients at high risk of nonunion fractures [1, 3, 5].
1, American Academy of Orthopedic Surgeons- Bone Growth stimulators: governance papers. http://www.aaos.org/govern/federal/issues/HumanaBoneGrowthStimulators.pdf Accessed 10/31/15