[Percutaneous dorsal versus open instrumentation for fractures of the thoracolumbar border. A comparative,...

A prospective clinical study.

To evaluate whether a percutaneous dorsal instrumentation of thoracolumbar fractures prevents irreversible damage to the spinal muscles.

A total of 57 patients with thoracolumbar fractures (Th12-L4) were divided into two groups, comparable in terms of gender, fracture level, classification and surgical concept. In the first, 24/57 patients were treated using an open procedure (OP-G); in the second, 33/57 were treated via percutaneous dorsal instrumentation (PER-G). Fracture localisation and classification, accuracy of pedicle screw placement, perioperative blood loss, OR- and image converter time as well as muscle damage (needle-EMG) were evaluated.

OR- and image converter time as well as the accuracy of pedicle screw placement were not statistically different between groups. The difference in perioperative blood loss [43 (10-90) ml (PER-G) vs [870 (570-1,200 ml (OP-G)] was statistically significant (P <0.005). Needle EMG revealed no muscle damage, and the physiological activity and muscle potentials were normal (PER-G). In the OP-G, polyphasic EMG signals were most common (80%), a sign of the drop-out of numerous motor units.

The open procedure caused permanent and significant damage to the strongest extensors of the autochthonus back musculature, the m. multifidus, which results from multisegment combined damage to the r. posterior nervi spinalis and muscle fibres. In contrast, percutaneous placement of an internal fixative reduces perioperative access morbidity causing little iatrogenic damage to back muscles and only a minor perioperative blood loss.