Direct Current Electrical Stimulation Increases the Fusion Rate of Spinal Fusion Cages

Study Design. A randomized experimental evaluation of direct current stimulation in a validated animal model with an experimental control group, using blinded radiographic, biomechanical, histologic, and statistical measures. Objectives. To evaluate the efficacy of the adjunctive use of direct current stimulation on the fusion rate and speed of healing of titanium interbody fusion cages packed with autograft in a sheep lumbar interbody fusion model. Summary of Background Data. Titanium lumbar interbody spinal fusion cages have been reported to be 90% effective for single-level lumbar interbody fusion. However, fusion rates are reported to be between 70% and 80% in patients with multilevel fusions or with risk factors such as obesity, tobacco use, or metabolic disorders. The authors hypothesized that direct current stimulation would increase the fusion rate of titanium interbody fusion cages packed with autograft in a sheep lumbar interbody fusion model. Methods. Twenty-two sheep underwent lumbar discectomy and fusion at L4–L5 with an 11- × 20-mm Bagby and Kuslich (BAK) cage packed with autograft. Seven sheep received a BAK cage and no current. Seven sheep had a cage and a 40-&mgr;A current applied with a direct current stimulator. Eight sheep had a BAK cage and a 100-&mgr;A current applied. All sheep were killed 4 months after surgery. The efficacy of electrical stimulation in promoting interbody fusion was assessed by performing radiographic, biomechanical, and histologic analyses in a blinded fashion. Results. The histologic fusion rate increased as the direct current dose increased from 0 &mgr;A to 40 &mgr;A to 100 &mgr;A (P < 0.009). Histologically, all animals in the 100-&mgr;A group had fusions in both the right and left sides of the cage. Direct current stimulation had a significant effect on increasing the stiffness of the treated motion segment in right lateral bending (P < 0.120), left lateral bending (P < 0.017), right axial rotation (P < 0.004), left axial rotation (P < 0.073), extension (P < 0.078), and flexion (P < 0.029) over nonstimulated levels. Conclusion. Direct current stimulation increased the histologic and biomechanical fusion rate and the speed of healing of lumbar interbody spinal fusion cages in an ovine model at 4 months.

[1]  N. Kahanovitz Spine update. The use of adjunctive electrical stimulation to enhance the healing of spine fusions. , 1996, Spine.

[2]  M. Markel,et al.  Cervical Interbody Fusion Cages: An Animal Model With and Without Bone Morphogenetic Protein , 1998, Spine.

[3]  V. Mooney,et al.  A Randomized Double-Blind Prospective Study of the Efficacy of Pulsed Electromagnetic Fields for Interbody Lumbar Fusions , 1990, Spine.

[4]  N. Kahanovitz,et al.  The Effect of Postoperative Electromagnetic Pulsing on Canine Posterior Spinal Fusions , 1984, Spine.

[5]  N. Kahanovitz,et al.  The effect of electromagnetic pulsing on posterior lumbar spinal fusions in dogs. , 1994, Spine.

[6]  P. Staniforth Electrical stimulation — Its role in growth, repair, and remodeling of the musculoskeletal system , 1988 .

[7]  W. Kane,et al.  Direct Current Electrical Bone Growth Stimulation for Spinal Fusion , 1988, Spine.

[8]  S. Pollack,et al.  Treatment of nonunion of the tibia with a capacitively coupled electrical field. , 1984, The Journal of trauma.

[9]  A. Rogozinski,et al.  Efficacy of Implanted Bone Growth Stimulation in Instrumented Lumbosacral Spinal Fusion , 1996, Spine.

[10]  S. Boden,et al.  Biologic enhancement of spinal fusion. , 1995, Spine.

[11]  C D Ray,et al.  Threaded Titanium Cages for Lumbar Interbody Fusions , 1997, Spine.

[12]  S. Furner,et al.  Musculoskeletal Conditions in the United States , 1992 .

[13]  T. Whitecloud,et al.  Degenerative conditions of the lumbar spine treated with intervertebral titanium cages and posterior instrumentation for circumferential fusion. , 1998, Journal of spinal disorders.

[14]  L. Claes,et al.  Are Sheep Spines a Valid Biomechanical Model for Human Spines? , 1997, Spine.

[15]  John R. Johnson,et al.  A double-blind study of capacitively coupled electrical stimulation as an adjunct to lumbar spinal fusions. , 1999, Spine.

[16]  A. Dwyer The use of electrical current stimulation in spinal fusion. , 1975, The Orthopedic clinics of North America.

[17]  B. Cunningham,et al.  Osteogenic protein versus autologous interbody arthrodesis in the sheep thoracic spine. A comparative endoscopic study using the Bagby and Kuslich interbody fusion device. , 1999, Spine.

[18]  S. Arnoczky,et al.  The Efficacy of Direct Current Electrical Stimulation to Enhance Canine Spinal Fusions , 1990, Clinical orthopaedics and related research.

[19]  S. Boden,et al.  Laparoscopic anterior spinal arthrodesis with rhBMP-2 in a titanium interbody threaded cage. , 1997, Journal of spinal disorders.

[20]  S. L. Griffith,et al.  The Bagby and Kuslich Method of Lumbar Interbody Fusion: History, Techniques, and 2‐Year Follow‐up Results of a United States Prospective, Multicenter Trial , 1998, Spine.

[21]  J. Haselkorn,et al.  Patient outcomes after lumbar spinal fusions. , 1992, JAMA.

[22]  J. Bubis,et al.  Stimulation of Bone Formation by Electrical Current on Spinal Fusion , 1986, Spine.

[23]  R. Delamarter,et al.  Distractive Properties of a Threaded Interbody Fusion Device: An In Vivo Model , 1996, Spine.

[24]  S. Boden,et al.  Biologic Enhancement of Spinal Fusion , 1995, The Orthopedic clinics of North America.

[25]  Allen J. Meril Direct Current Stimulation of Allograft in Anterior and Posterior Lumbar Interbody Fusions , 1994, Spine.

[26]  Dwyer Af The use of electrical current stimulation in spinal fusion. , 1975 .

[27]  B. Weiner,et al.  Lumbar Interbody Cages , 1998, Spine.

[28]  W. Hayes,et al.  In vivo evaluation of coralline hydroxyapatite and direct current electrical stimulation in lumbar spinal fusion. , 1999, Spine.

[29]  G. Andersson Epidemiological features of chronic low-back pain , 1999, The Lancet.

[30]  V K Goel,et al.  Materials and design of spinal implants--a review. , 1997, Journal of biomedical materials research.

[31]  P. McAfee,et al.  Minimally Invasive Anterior Retroperitoneal Approach to the Lumbar Spine: Emphasis on the Lateral BAK , 1998, Spine.

[32]  S. Pollack,et al.  Treatment of recalcitrant non-union with a capacitively coupled electrical field. A preliminary report. , 1985, The Journal of bone and joint surgery. American volume.

[33]  G. Bagby Arthrodesis by the distraction-compression method using a stainless steel implant. , 1988, Orthopedics.