Effect of Botox and Vibration on Bone in Children With Cerebral Palsy

Alfred I. duPont Hospital for Children, Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Cerebral palsy (CP) is a neuromuscular disorder that affects approximately 800,000 individuals in the U.S. An estimated 70-80% of these individuals have spasticity which affects ambulation and requires management. Therefore, the treatment of spasticity is a primary goal of interventions for children with CP. One treatment widely used to reduce spasticity is Botox because of its ability to temporarily paralyze a muscle. However, no studies have determined the effect of Botox treatment on bone in humans. Also, a low magnitude vibration treatment has been shown to improve bone structure in the lower extremity bones of children with CP. The aims of this study are: 1) to determine the effect of Botox treatment in conjunction with a daily vibration treatment on bone mass and bone structure in children with spastic CP, and 2) to identify the mechanism that underlies the effect of Botox and vibration on bone.

The investigators have been working with children diagnosed with cerebral palsy (CP) for the past 10 years. The investigators have found that bone structure is markedly underdeveloped and bone strength is severely compromised in children with CP. Also, an increased fracture rate has been observed in the lower extremity bones of children with CP. There is evidence that Botox, which is used to treat spasticity in CP, can improve motor function; however the effect of Botox on human bone is unknown. There is also evidence that low magnitude vibration treatment can improve bone mass and bone structure. The overall goal of this current research study is to investigate the effect and mechanism of action of Botox and vibration on bone in children with CP. The investigators will also examine the effect of Botox on muscle volume. A total of 36 participants will participate in this study. The investigators will assess bone structure and muscle volume using MRI. The investigators will assess bone mass using dual-energy X-ray absorptiometry (DXA).

Change in cortical bone volume of the middle third of the tibia from baseline to 6 months, as measured by MRI.

Change in bone mineral content in the distal femur from baseline to 6 months, as measured by dual-energy X-ray absorptiometry (DXA)

Inclusion (Children with CP): Have spastic CP Between 2-12 years of age Recommended for Botox treatment by their physician as part of their clinical care. Those who accept Botox treatment and those who do not accept Botox treatment are both eligible for the study. A score of 1-4 on the gross motor function classification scale (GMFCS) Exclusion (Children with CP): Botox treatment in the lower extremities within the last year Metal rods in both legs Inclusion (Typically developing children): Between 2 and 12 years of age. Match a child with CP for sex, age and race. Exclusion(Typically developing children): Neurological disorder Surgery in the lower extremities within the last year. Chronic medication use

De-identified individual participant data for all primary and secondary outcome measures will be made available.

Data access requests will be reviewed by the PIs. Requestors will be required to sign a Data Access Agreement.

Johnson DL, Miller F, Subramanian P, Modlesky CM. Adipose tissue infiltration of skeletal muscle in children with cerebral palsy. J Pediatr. 2009 May;154(5):715-20. doi: 10.1016/j.jpeds.2008.10.046. Epub 2008 Dec 25.

Modlesky CM, Subramanian P, Miller F. Underdeveloped trabecular bone microarchitecture is detected in children with cerebral palsy using high-resolution magnetic resonance imaging. Osteoporos Int. 2008 Feb;19(2):169-76. doi: 10.1007/s00198-007-0433-x. Epub 2007 Oct 26.

Rubin C, Turner AS, Muller R, Mittra E, McLeod K, Lin W, Qin YX. Quantity and quality of trabecular bone in the femur are enhanced by a strongly anabolic, noninvasive mechanical intervention. J Bone Miner Res. 2002 Feb;17(2):349-57. doi: 10.1359/jbmr.2002.17.2.349.

Judex S, Boyd S, Qin YX, Turner S, Ye K, Muller R, Rubin C. Adaptations of trabecular bone to low magnitude vibrations result in more uniform stress and strain under load. Ann Biomed Eng. 2003 Jan;31(1):12-20. doi: 10.1114/1.1535414.

Wren TA, Lee DC, Hara R, Rethlefsen SA, Kay RM, Dorey FJ, Gilsanz V. Effect of high-frequency, low-magnitude vibration on bone and muscle in children with cerebral palsy. J Pediatr Orthop. 2010 Oct-Nov;30(7):732-8. doi: 10.1097/BPO.0b013e3181efbabc.

Ward K, Alsop C, Caulton J, Rubin C, Adams J, Mughal Z. Low magnitude mechanical loading is osteogenic in children with disabling conditions. J Bone Miner Res. 2004 Mar;19(3):360-9. doi: 10.1359/JBMR.040129. Epub 2004 Jan 27.

Modlesky CM, Whitney DG, Singh H, Barbe MF, Kirby JT, Miller F. Underdevelopment of trabecular bone microarchitecture in the distal femur of nonambulatory children with cerebral palsy becomes more pronounced with distance from the growth plate. Osteoporos Int. 2015 Feb;26(2):505-12. doi: 10.1007/s00198-014-2873-4. Epub 2014 Sep 9.

Modlesky CM, Whitney DG, Carter PT, Allerton BM, Kirby JT, Miller F. The pattern of trabecular bone microarchitecture in the distal femur of typically developing children and its effect on processing of magnetic resonance images. Bone. 2014 Mar;60:1-7. doi: 10.1016/j.bone.2013.11.009. Epub 2013 Nov 20.

Singh H, Whitney DG, Knight CA, Miller F, Manal K, Kolm P, Modlesky CM. Site-Specific Transmission of a Floor-Based, High-Frequency, Low-Magnitude Vibration Stimulus in Children With Spastic Cerebral Palsy. Arch Phys Med Rehabil. 2016 Feb;97(2):218-23. doi: 10.1016/j.apmr.2015.08.434. Epub 2015 Sep 21.