1. Cairo University, Kasr
Al-Aini Str., 11562 CairoEgypt.
2. RWTH Aachen University, Department
of Orthopaedic Surgery, Pauwelsstr. 30, D-52074
Aachen, Germany.
3. RWTH Aachen University, Department
of Pediatric Oncology, Pauwelsstr. 30, D-52074 Aachen, Germany.