J Korean Neurosurg Soc.  2009 Jul;46(1):45-51. 10.3340/jkns.2009.46.1.45.

The Effect of Risedronate on Posterior Lateral Spinal Fusion in a Rat Model

• Gezici AR
• Ergun R
• Gurel K
• Yilmaz F
• Okay O
• Bozdogan O

• KMID: 2189885
• DOI: http://doi.org/10.3340/jkns.2009.46.1.45

Abstract

OBJECTIVE
To evaluate the potential effects of risedronate (RIS) which shows a higher anti-resorptive effect among bisphosphonates, after a posterolateral lumbar intertransverse process spinal fusion using both autograft and allograft in a rat model. METHODS: A totoal of 28 Sprague-Dawley rats were randomized into 2 study groups. A posterolateral lumbar intertransverse process spinal fusion was peformed using both autograft and allograft in a rat model. Group I (control) received 0.1 mL of steril saline (placebo) and Group II (treatment) received risedronate, equivalent to human dose (10 microgram/kg/week) for 10-weeks period. RESULTS: The fusion rates as determined by manual palpation were 69% in the group I and 46% in the group II (p = 0.251). According to radiographic score, the spinal segment was considered to be fused radiographically in 7 (53%) of the 13 controls and 9 (69%) of the 13 rats treated with RIS (p = 0.851). The mean histological scores were 5.69 +/- 0.13 and 3.84 +/- 0.43 for the control and treatment groups, respectively. There was a significant difference between the both groups (p = 0.001). The mean bone density of the fusion masses was 86.9 +/- 2.34 in the control group and 106.0 +/- 3.54 in the RIS treatment group. There was a statistical difference in mean bone densities of the fusion masses comparing the two groups (p = 0.001). CONCLUSION: In this study, risedronate appears to delay bone fusion in a rat model. This occurs as a result of uncoupling the balanced osteoclastic and osteoblastic activity inherent to bone healing. These findings suggest that a discontinuation of risedronate postoperatively during acute fusion period may be warranted.

Keyword

Rats; Risedronate; Spinal fusion; Spine

MeSH Terms

Animals
Bone Density
Diphosphonates
Etidronic Acid
Humans
Osteoblasts
Osteoclasts
Palpation
Rats
Rats, Sprague-Dawley
Spinal Fusion
Spine
Transplantation, Homologous
Risedronate Sodium
Diphosphonates
Etidronic Acid