Percutaneous approach to the upper thoracic spine: optimal patient positioning

Abstract

Percutaneous access to the upper thoracic vertebrae under fluoroscopic guidance is challenging. We describe our positioning technique facilitating optimal visualisation of the high thoracic vertebrae in the prone position. This allows safe practice of kyphoplasty, vertebroplasty and biopsy throughout the upper thoracic spine.

Introduction

Boszczyk et al. [2] have advocated fluoroscopically guided kyphoplasty cranial to T5. They have shown the trans-costovertebral approach to the high thoracic spine can be successfully used for kyphoplasty, vertebroplasty and biopsy.

Optimal visualisation is paramount for safe placement of instruments due to the close proximity of the spinal canal, the pleural cavity and major vascular structures. With conventional prone positioning, the scapula and humeral head are superimposed on the spine in the lateral image.

We describe a simple patient positioning modification that significantly improves the lateral visualisation of the upper thoracic spine during percutaneous procedures.

Technique

The patient is positioned prone on conventional bolsters. The arms remain adducted. A midline longitudinal bolster is placed under the sternum allowing the scapulae to fall anteriorly avoiding overlay of the shoulder girdle on the lateral fluoroscopic image (Figs. 1, 2, 3).

Fig. 1.

Patient positioning for percutaneous access to upper thoracic spine. a, b, c Bolster placement: a lateral, b head end, c head end with head cushion removed

Fig. 2.

Patient positioning for percutaneous access to upper thoracic spine. Schematic views of shoulders displacing anteriorly. a from head end, b lateral (Illustrations courtesy of spinegraphics@gmx.net)

Fig. 3.

Patient positioning for percutaneous access to upper thoracic spine. Patient positioned with sternal bolster during general anaesthetic (lateral view)

For those procedures performed under sedation rather than general anaesthetic, a midline longitudinal sternal bolster is still positioned, but the arms can be placed with the shoulders abducted and elbows flexed as shown. This is more comfortable for the patient and still allows good visualisation up to T2 (Fig. 4).

Fig. 4.

Patient positioning for percutaneous access to upper thoracic spine. Patient positioned for procedures under sedation a from head end, b lateral view

In our experience, this has allowed clear fluoroscopic visualisation of the upper thoracic spine (Fig. 5).

Fig. 5.

a, b Lateral fluoroscopic image obtained with this technique: a During placement of K-wires, b during injection of PMMA cement (images show T2–T7 with T4–T7 injected with PMMA cement)

Discussion

Ottolenghi [8] was the first to advocate thoracic vertebral biopsy above T9 and described the intercostal approach. More recently, trans-pedicular and trans-costovertebral approaches have been described [1, 3–6, 9]. CT guidance has been described as safer than fluoroscopic guidance [10]; however, a recent meta-analysis has suggested no significant difference in complication rates (3.3–5.3%) [7].

We favour the trans-costovertebral approach using fluoroscopic guidance, as described by Boszczyk et al. [2]. This allows safe use of large cannulas or biopsy needles with a potentially larger diameter than the upper thoracic pedicles, thus avoiding spinal canal intrusion.

The described modified position allows clear fluoroscopic lateral imaging of the upper thoracic spine. The image is not obscured by the shoulder girdle. This facilitates safe cannula or needle placement in the upper thoracic spine. We have accessed 23 vertebrae between T1 and T5 successfully with this technique.