Teli M, Grava G, Solomon V, Andreoletti G, Grismondi E, Meswania J. Measurement of forces generated during distraction of growing-rods in early onset scoliosis. World J Orthop 2012; 3(2): 15-19 [PMID: 22470846 DOI: 10.5312/wjo.v3.i2.15]
Corresponding Author of This Article
Dr. Marco Teli, Consultant Orthopaedic Surgeon, Orthopaedic Spine Unit, Policlinico San Marco, Residence Grancia, Via Tevere 7, 20020 Lainate, Milano, Italy. marcoteli@hotmail.com
Article-Type of This Article
Brief Article
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World J Orthop. Feb 18, 2012; 3(2): 15-19 Published online Feb 18, 2012. doi: 10.5312/wjo.v3.i2.15
Measurement of forces generated during distraction of growing-rods in early onset scoliosis
Marco Teli, Giuseppe Grava, Victor Solomon, Giuseppe Andreoletti, Emanuele Grismondi, Jay Meswania
Marco Teli, Consultant Orthopaedic Surgeon, Orthopaedic Spine Unit, Policlinico San Marco, Corso Europa 7, 24040 Osio Sotto, Bergamo, Italy
Giuseppe Grava, Victor Solomon, Giuseppe Andreoletti, Consultant Orthopaedic Surgeon, Orthopaedic Department, Policlinico San Marco, Corso Europa 7, 24040 Osio Sotto, Bergamo, Italy
Emanuele Grismondi, Staff Grade Surgeon, Orthopaedic Department, Policlinico San Marco, Corso Europa 7, 24040 Osio Sotto, Bergamo, Italy
Jay Meswania, Biomedical Engineer, Royal National Orthopaedic Hospital, Stanmore, United Kingdom
Author contributions: Teli M and Meswania J designed and obtained the experimental data; Meswania J put the data into charts and did the analysis; Teli M, Grava G, Solomon V, Andreoletti G and Grismondi E revised the data and wrote the text.
Correspondence to: Dr. Marco Teli, Consultant Orthopaedic Surgeon, Orthopaedic Spine Unit, Policlinico San Marco, Residence Grancia, Via Tevere 7, 20020 Lainate, Milano, Italy. marcoteli@hotmail.com
Telephone: +39-02-93559100 Fax: +39-0331-449459
Received: August 19, 2011 Revised: December 28, 2011 Accepted: February 16, 2012 Published online: February 18, 2012
Abstract
AIM: To measure the forces applied during distraction of growing-rods in early onset scoliosis (EOS), aimed at developing a motorized elongation device.
METHODS: A consecutive series of measurements were carried out to analyze the forces applied by the surgeon during distraction of single growing-rods in 10 patients affected by EOS (mean age 8.3 years; range 6 to 10 years) undergoing the first distraction 6 months following implantation of the rods. For each measurement, output from the transducer of a dedicated pair of distraction calipers was recorded at zero load status and at every 1 mm of distraction, up to a maximum of 12 mm for each of the two connected rods.
RESULTS: Twenty measurements were obtained showing a linear increase of the load with increasing distraction, with a mean peak force of 485 N at 12 mm distraction and a single reading over 500 N. We did not observe bone fractures or ligament disruptions during or after rod elongations. There was one case of superficial wound infection in the cohort.
CONCLUSION: The safe peak force carrying capacity of a motorized device for distraction of growing-rods is 500N.
