1. Validation of a bone analog model for studies of sternal closure
Dennis R Trumble, MS, Walter E McGregor, MD, James A Magovern, MD 
The Annals of Thoracic Surgery 
Volume 74, Issue 3, Pages (September 2002)
DOI: /S (02)

2. Fig 1
Experimental setup used to apply traction forces to the sterna of intact human cadavers. A rigid enclosure fashioned from steel pipe (0.85-inch outer diameter) was used to provide stable anchoring points for sternal traction in three mutually-orthogonal directions: lateral (shown here), rostral-caudal, and anterior-posterior. Force was applied through steel cables secured to the second, fourth, and sixth ribs at their insertion points and adjusted using a turnbuckle mechanism. Bone fracture was prevented by pressing each rib between two brass plates using a small metal hose clamp (to which the cable was attached). Sternal motion was monitored using four pairs of sonomicrometry crystals and tension measured by an S-beam load cell. Reproduced with permission from McGregor et al [8].
The Annals of Thoracic Surgery  , DOI: ( /S (02) )

3. Fig 2
Synthetic sternal model (19 × 6.5 cm) separated bilaterally and reapproximated using six interrupted wire closures. All sterna used in this study were formed to replicate human anatomical structures and cast from solid polyurethane foam mixed to a density of 20 lbs/ft3.
The Annals of Thoracic Surgery  , DOI: ( /S (02) )

4. Fig 3
Sternal closure test apparatus shown with rod/bushing stabilizing mount on the left and anchoring base plate on the right. The worm screw tensioning device and load cell (not shown) are stationed to the left of the stabilizing mount. Traction forces are applied through a series of cables and turnbuckles and uniform tension distribution maintained by a levered adjustment mechanism (middle right). Sternal motion is measured using three linear potentiometers mounted across the manubrium, midsternum, and xiphoid regions of the sternal model.
The Annals of Thoracic Surgery  , DOI: ( /S (02) )

5. Fig 4
Plots of sternal displacement versus traction force for standard interrupted closures in human cadavers and sternal models. Top, middle, and lower graphs show motion at the manubrium, midsternum, and xiphoid regions respectively. Data are mean ± SD.
The Annals of Thoracic Surgery  , DOI: ( /S (02) )

6. Fig 5
Plots of sternal displacement versus traction force for figure-of-eight closures in human cadavers and sternal models. Top, middle, and lower graphs show motion at the manubrium, midsternum, and xiphoid regions respectively. Data are mean ± SD.
The Annals of Thoracic Surgery  , DOI: ( /S (02) )