Vertebral Augmentation (Vertebroplasty/Kyphoplasty): Transpedicular Approach

Abstract

Vertebral body compression fractures are estimated to occur approximately 700,000 times each year. This presents a significant public health challenge from the standpoints of morbidity, mortality, and health care expenditures. Pain reduction, vertebral body stabilization, and rapid return to function are paramount for those who are affected with this disabling condition.

Keywords

compression fracture, fluoroscopy, kyphoplasty, vertebral augmentation, vertebroplasty

Note: Please see pages ii , iii for a list of anatomic terms/abbreviations used throughout this book.

Vertebral body compression fractures are estimated to occur approximately 700,000 times each year. This presents a significant public health challenge from the standpoints of morbidity, mortality, and health care expenditures. Pain reduction, vertebral body stabilization, and rapid return to function are paramount for those who are affected with this disabling condition.

Although alternative techniques have been described, the approach described here involves the use of a trajectory view as the primary approach. The vertebral body is cannulated in the trajectory view (see Appendix 1 ). Fig. 19.11 demonstrates the angulation of the needle trajectory in the lateral view with various fracture pattern scenarios.

The described procedure has three phases: (1) transpedicular advancement, (2) vertebral body advancement and balloon inflation for kyphoplasty, and (3) bone cement injection. As is emphasized throughout this text, safety is mediated by judiciously using multiplanar views during the procedure.

A key operational difference between kyphoplasty and vertebroplasty lies in the placement of the working cannula. During kyphoplasty, when the osteo introducer anchors 1 to 2 mm ventral to the posterior vertebral body (see Fig. 19.3 A ). a biopsy can be taken; alternatively, the drill can be used to create a path for the balloon tamp (see Fig. 19.10 A and B ). During vertebroplasty, the introducer cannula is driven from the pedicle toward the midline of the vertebral bone without additional instrumentation. When the cannula tip has docked into the posterior vertebral body (see Fig. 19.3 A ), the tip medial to the pedicle is expected to be visualized in the anteroposterior view; however, advancement should always be done in the lateral view to protect the great vessels.

The oblique transpedicular view is identical to the trajectory view ( Fig. 19.1 ), as previously described.

Transpedicular Advancement: Trajectory View ( Fig. 19.1 )

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Confirm the level (with the anteroposterior view).
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Tilt the C-arm to line up the inferior endplate of the vertebral body to be treated.
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Ipsilateral oblique approximately 10 to 20 degrees so that the pedicle appears as a clock face.
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Position the pedicle in the oblique view so that it is completely superimposed within the outline of the vertebral body.
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The transpedicular entry point is the superior lateral quadrant (i.e., the 10 or 2 o’clock position for left or right entry, respectively) for fractures occurring along the superior end plate (majority of fractures).
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For biconcave and planar fractures, entering in the middle of the pedicle will provide optimal placement (see Fig. 19.11 ).
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For inferior end plate fractures, a 7 or 5 o’clock position for cannulation should be achieved.
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Anesthetize the needle tract and periosteum overlying the pedicle.
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Nick the skin (No. 11 blade for kyphoplasty or an 18-G needle for vertebroplasty).
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Insert the osteo introducer device or the bone needle, and place the tip onto the pedicle.
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Gently tap the bone needle with a mallet to create a starting hole.
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Advance the needle with gentle manual pressure or mallet tapping.

Trajectory View Safety Considerations

Avoid the spinal cord and thecal sac (TS) contents by staying lateral to the medial border of the pedicle.
Avoid the superior and inferior nerve roots and spinal nerves by staying within the inferior and superior pedicular borders.
Avoid pneumothorax during thoracic vertebral body augmentation by avoiding violation of the lateral wall of the vertebral body by traversing in a lateral-to-medial intrapedicular pathway.

Multiplanar Views During Transpedicular Advancement ( Figs. 19.2 and 19.3 )

Anteroposterior View

Anteroposterior View Safety Considerations

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Avoid the spinal cord and dural sac by maintaining the osteo introducer tip lateral to the medial border of the pedicle.
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Once through the pedicle, the cannula tip should be seen at the posterior vertebral body wall, advance in the lateral imaging.