Although the underlying cause in many TOS cases is unknown, the most widely recognized cause of TOS is an elongated transverse process of C7 which compresses the brachial plexus. TOS is generally believed to result from one of two major factors, compression and infection. There is also a paucity of information concerning the course of TOS among younger patients. This study was designed, therefore, to explore the causes of the disease and best treatments, as well as the prognosis in young patients with TOS. In most studies, the main treatment option has been surgery, but in this retrospective study, both surgical and nonsurgical treatments were explored, and all patients were followed-up from 6 months to 2 years.
Materials and methods

Patients

Our study protocol was approved by Huashan Institutional Review Board (HIRB). Written informed consent was obtained from the parents of every child prior to their participation in the study.
All children under the age of 18 with TOS who underwent treatment for TOS at our hospital between January 2008 and June 2014 were enrolled in the study.
The inclusion criteria were: (1) typical clinical presentations of TOS; (2) positive results on Wright’s and Adson’s tests, and a positive Hoffmann’s reflex; (3) electromyographic (EMG) findings supporting a diagnosis of TOS; and (4) age younger than 18 years. Children with congenital brachial plexus injury, obstetric brachial plexus palsy, congenital torticollis, endocrine diseases (such as peripheral neuropathy caused by pediatric diabetes), or a recent history of trauma were excluded from the study.
A final group of 13 patients (3 boys and 10 girls) from 4 to 13 years of age (mean age, 8 years) who met our criteria were included in the study.

### Language ###
English

### Assessment ###
Could ask about the gender distribution of children in this medical study

### Query ###
How many boys and girls participated in the study of thoracic outlet syndrome in children?
How many boys and girls participated in the study of thoracic outlet syndrome in children?