The endoscopically assisted simultaneous posteroanterior reconstruction of the thoracolumbar spine in prone position

The reconstruction of the anterior column of the thoracolumbar spine has become more common in the last few years, due largely to the unfavorable results of exclusively posterior surgical treatment, which has been associated with a lack of about 10 degrees of kyphosis correction after removal of the instrumentation. The minimally invasive anterior techniques have reduced the morbidity of the anterior approach significantly.

A minimally invasive technique for anterior stabilization of the spine may reduce the morbidity of the open approach. Irrespective of an anterior open or an endoscopic approach, the posteroanterior instrumentation of thoracolumbar fractures requires time-consuming intraoperative maneuvers to change the patient position from prone to lateral. We describe here a standardized anterior endoscopically assisted approach for the segments T4 to L4. This approach allows the patient to remain in prone position. A 4- to 5-cm incision combined with a retractor system is used.

In a prospective study, all patients of our clinic who underwent surgery of the thoracolumbar spine between July 1999 and May 2001 were registered. Study criteria were duration of surgery, duration of anesthesia, intra- and postoperative complications.

Between July 1999 and May 2001, 42 patients (25 male, 17 female, average age of 41.9 years), who presented with 55 injured spinal levels and underwent surgery of the thoracolumbar spine in prone position, were included.

Duration of surgery (posterior/anterior/total), duration of anesthesia, method of instrumentation, intra- and postoperative complications, postoperative hospital stay and radiographs were evaluated.

Surgery was performed in prone position. A thoracic approach was used for instrumentation of T9 to L2. A retroperitoneal approach was used for stabilization of L1 to L5. Both procedures were endoscopically assisted with a new retractor system (Synframe; Synthes GmbH, Umkirch, Germany). In this manner, only an incision 4 to 5 cm long and a stab incision for the endoscope were required. The whole procedure was performed in prone position without a change of position during surgery.

A total of 42 patients underwent surgery following this technique: 14 isolated anterior procedures (median duration of surgery, 181 minutes); 13 simultaneous one-stage procedures (median duration of surgery: 210 minutes) and 15 combined two-stage procedures (median duration of surgery: 90 minutes posterior, 120 minutes anterior, 240 minutes posterior+anterior). In the simultaneous posteroanterior procedures, the anterior instrumentation was performed 20 times using one rod, twice using two rods and in six patients simply by bone grafting. No intraoperative complications were observed. In the postoperative course, one case of pneumothorax, one case of hemothorax and one case of transient intercostal neuralgia occurred.

The approach to the anterior spine in prone position is feasible by using a self-holding retractor system for the region between T4 and L4. The duration of anesthesia for the one-stage simultaneous procedure was reduced by about 40 minutes, because changing the position of the patient is no longer necessary. The minimal incision, in combination with the retractor system, significantly reduces cost by allowing the use of less expensive instruments and implants. The advantages of the open and the endoscopic techniques are combined, while their disadvantages are minimized. The main advantage of the prone position is the opportunity to access the anterior and posterior spine simultaneously, which is especially helpful in reduction maneuvers.