A Commentary on “The effects of extracorporeal shock wave therapy in children with cerebral palsy: a systematic review”

Dear Editor, Cerebral palsy (CP) refers to a collection of long-lasting but non-progressive impairments of posture and movement that are caused by injury to the developing fetus or newborn brain[1]. Disturbances in cognition, perception, sensation, epilepsy, behavior, communication, and secondary musculoskeletal problems often coexist with the motor disorders linked to CP. According to reports, it affects two out of 1000 live births. Numerous factors throughout the postnatal, perinatal, or prenatal periods might cause this condition. With its potential advantages of being non-invasive and having few side effects, extracorporeal shock wave therapy (ESWT) has become a viable treatment for CP. De Roo et al[2] conducted a comprehensive evaluation of twelve RCTs (Table 1) to examine the impact of ESWT in children with CP. They came to the conclusion that children with CP undergoing ESWT showed increases in passive range of motion, gross motor skills, as well as resistance to passive movements. Table 1 - Characteristics of included studies Study Study design Population Intervention ESWT settings Muscle group Wardhani, et al (2021) RCT 13 children (9 boys, 4 girls), 4–15 years. 1 session ESWT Group 1: 500 shocks, 1.5 bar, 4 Hz Hamstrings Group 2: 1000 shocks, 1.5 bar, 4 Hz Group 1: 5 boys, mean age 10.6 years Group 3: 1500 shocks, 1.5 bar, 4 Hz Group 2: 2 boys, 4 girls, mean age 6.5 years Group 3: 6 boys, 1 girl, mean age 10.7 years Group 4: 2000 shocks, 1.5 bar, 4 Hz Group 4: 4 boys, 3 girls, mean age 9.1 years Gonkova et al (2013) Placebo-controlled double-blinded study 25 children (16 boys, 9 girls) mean age 4.84 years 1 session ESWT and 1 session placebo with 4 weeks in between the sessions 1500 shocks, 1.5 bar, 5 Hz Calf muscles Bilek et al (2021) RCT 32 children with unilateral CP (16 boys, 16 girls) Study group: NDT 2 ×/week + ESWT 2 ×/ week, for 8 weeks 1500 shocks, 1.2 bar, 4 Hz Paravertebral muscles Study group: Mean age 10.06 years Control group: Mean age 10.19 years Control group: NDT 2 ×/ week, for 8 weeks El-Shamy et al (2014) RCT 30 children with unilateral CP Study group: conservative physiotherapy, 1 hour a day, 3 days a week for 3 months i. c.w. ESWT once a week for 3 months. 1500 shocks, 1.5 bar, 5 Hz, 0.03 mJ/mm Calf muscles Study group: 9 boys, 6 girls, mean age 6.93 years Control group: 9 boys 6 girls, mean age 6.8 years Control group: conservative physiotherapy, 1 hour a day, 3 days a week for 3 months Wang et al (2016) Prospective case control 66 children with CP Study group: 3 months, once a week 1500 shocks, 8 Hz, 0.03 mJ/mm Calf musculature Study group: 23 boys, 11 girls, mean age 26.9 months ESWT combined with conservative therapy 6 days a week, 30 minutes. Control group: 21 boys, 11 girls, mean age 40.2 months Control group: 3 months conservative therapy Amelio et al (2010) Open placebo-controlled study 12 children (6 boys, 6 girls) 6–11 years with unilateral CP, mean age 8 years 1 placebo treatment and 6 weeks later 1 ESWT- treatment 1500 shocks, 0.03 mJ/mm Calf musculature Farhan et al (2019) RCT 32 children with unilateral CP between 5 and 15 years Study group: 2 months, 3 × a week exercise andonce a week ESWT 2000 shocks, 4 bar, 15 Hz Wrist and elbow flexors Study group: 10 boys, 6 girls mean age 6.37 years Control group: 2 months, 3 × a week exercises Control group 7 boys, 9 girls, mean age 6.68 years Gawad et al (2014) RCT 30 children from 5–7 years with unilateral CP Study group: exercises + ESWT 1 week 3 times 2000 shocks, 0.32 mJ/mm Calf musculature Study group: 15 children (6 boys, 9 girls) mean age 5.75 years Control group: exercises Control group: 15 children (6 boys, 9 girls) mean age 5.83 years Emara et al (2022) Randomized clinical trial 34 children from 7–9 years with spastic unilateral CP Study group: exercises 3 × 1 hour/week for 12 weeks + ESWT once week 2000 shocks, 4 bar, 15 Hz Calf musculature Study group: 10 boys, 7 girls, mean age 7.80 years Control group: exercises 3 × 1 hour/week for 12 weeks Control group: 9 boys, 8 girls mean age 7.92 years Park et al (2015) Pilot study Study group: 6 children (3 boys, 3 girls), 4 children with bilateral spastic CP and 2 with unilateral spastic CP; mean age 6.8 years Study group: 3 ESWT treatments once a week 1500 shocks, 0.03 mJ/mm, 4 Hz Calf musculature Control group: 6 children (4 boys, 2 girls), 4 children with spastic bilateral CP and 2 with spastic unilateral CP; mean age 7.0 years Control group: 1 ESWT treatment, 2 placebo treatments Lin et al (2018) RCT 82 children with spastic CP Study group: conservative physiotherapy and 2000 shocks, 2.0 bar, 10 Hz Hamstrings and triceps surae Study group: 43 children; mean age 7.5 years ESWT for 4 weeks, once a week Control group: 39 children; mean age 7.9 years Control group: conservative physiotherapy for 4 weeks Elnagger et al (2019) RCT 53 children with spastic bilateral CP 5–8 years Group 1: ESWT + trainings program (3 × 1 hour/week for 3 months) 1200 shocks, 1.5 bar, 5 Hz Calf musculature Group 1: 10 boys 8 girls; mean age 7.11 years Group 2: 13 boys 3 girls; mean age 6.94 years Group 2: SOM + trainings program (3 × 1 hour/week for 3 months) Group 3: 15 boys 4 girls; mean age 6.36 years Group 3: ESWT + SOM + trainings Program (3 × 1 hour/week for 3 months) CP, cerebral palsy; ESWT, extracorporeal shock wave therapy; NDT, neuro developmental treatment; RCT, randomized controlled trial; SOM, standard orthotic management. Although the exact mechanism underlying the decrease in spasticity linked to ESWT is yet unknown, it may entail ESWT facilitating the release of nitric oxide (NO). In the peripheral nervous system, NO production can influence the development of neuromuscular junctions, which can lessen muscle stiffness and promote neovascularization of muscles and tendons. The synaptic excitation, memory, and neurotransmission in central nervous system are all impacted by NO production. Low-frequency mechanical vibration of fibrosis sites and spastic muscles has also been identified as a potential mechanism. This vibration lowers the passive stiffness of muscles, which in turn decreases hyperexcitability in alpha motor neurons and activates the Golgi tendon organ. The passive range of motion and Modified Asworth Scale (MAS) were used as outcome measures in several of the included studies[3,4]. Eight studies examined the MAS, while four investigated the passive range of motion. Additionally, it was discovered that the foot placement and pressure of children greatly improved after ESWT, and their gait significantly improved. The application of ESWT may reduce the requirement for muscle-lengthening surgeries in children with hyper-resistance due to CP. However, more research needs be done in the future to determine the ideal ESWT parameters. There are some limitations to this study. (1) A variety of ESWT applications, either with or without additional treatments, are utilized in the included investigations. As a result, pool data from several research were not feasible. This brings bias into the efficacy assessment. Additionally, different studies employing ESWT in CP children have different intervention parameters. (2) The decreased validity and substantial heterogeneity of this study’s findings resulted from the included studies’ vast variations in afflicted locations, spastic cerebral palsy subtypes, and outcome measurement techniques. (3) This study was unable to do a more thorough investigation of the efficacy of ESWT in treating CP due to the small sample sizes, inadequate statistical data, and few RCTs. (4) The majority of included studies only evaluated outcomes before and after the intervention. Further research with long-term follow-up is needed. This study adheres to the TITAN Guidelines 2025[5].