Study design: A retrospective evaluation of screw position after double rod anterior spinal fusion in idiopathic scoliosis using computerised tomography (CT).

Objective: To evaluate screw position and complications related to screw position after double rod anterior instrumentation in idiopathic scoliosis.

Summary of Background Data: Anterior instrumentation and fusion in idiopathic scoliosis is gaining widespread use. However, no studies have been published regarding the accuracy of screw placement and screw related complications in double rod and double screw anterior spinal fusion and instrumentation in idiopathic thoracolumbar scoliosis surgery.

Methods: CT examinations were performed after anterior spinal fusion and instrumentation in 17 patients with idiopathic scoliosis. The vertebral rotation at each level was measured. At each instrumented level the position of the screw and the plate relative to the spinal canal, relative to the neural foramen and relative to the aorta was measured. Complications related to screw position were registered.

Results: 189 screws in 17 patients were evaluated. The average age of the patients was 31 years (range 15–53 years). Fourteen patients had a left convex thoracolumbar curve and three patients a right convex thoracolumbar curve. The mean lumbar apical rotation preoperatively was 27°. Malposition occurred in 23% of the total number of screws. Three screws were in the spinal canal (1%). This resulted in pain in the right leg. However, electromyography showed no abnormalities. On three levels there was contact between the instrumentation and the aorta. No vascular complications did occur. 113 screws (ten patients) were placed under fluoroscopic guidance and 76 screws (seven patients) were placed without use of fluoroscopy. No complications related to screw position were observed in the group in which the screws were placed under fluoroscopic guidance.

Conclusions: Adequate placement of two screws in the vertebra in idiopathic scoliosis is a technically demanding procedure, which results in frequent malposition, fortunately with a low risk of neurological and vascular complications.

Study design: Prospective study after minimally invasive anterior approach of the thoracolumbar spine in scoliosis correction.

Objective: To describe the technique and first results after minimally invasive anterior approach of the thoracolumbar junction with insertion of double rod and double screw instrumentation.

Summary of Background Data: Minimally invasive techniques are used at many areas of surgery nowadays. Minimally invasive surgery should have the same correction potential as with conventional approaches. Possible advantages of minimally invasive surgery are small incisions, less tissue damage, less morbidity and an improved cosmetic appearance.

Methods: In this study we describe the technique and the preliminary results of minimally invasive open approach of the thoracolumbar spine with insertion of double rod and double screw instrumentation. A consecutive series of seven patients were included. All patients were female with a mean age of 16.7 years (range 10–28). The cause of thoracolumbar scoliosis was mixed.

Results: The thoracolumbar curve was 59° preoperatively and 22° at six months follow up (63% correction). The unfused thoracic curve was 40° preoperatively and 29° at six months follow-up. In the sagittal plane of the fused levels Cobb angle was 61° of lordosis preoperatively and 35° of lordosis at six months follow up. Lumbar lordosis of the unfused spine was 16° preoperative and 5° at six months follow up. Thoracic kyphosis was 33° preoperatively and 24° at six months follow-up. The average time of surgery was 6.6 hours (range 5.5–7hours). The average estimated blood loss was 764ml (range 350–1200ml). Average hospital stay was 11 days (range 5–14days), and average stay at the intensive care unit was 1.7 days (range 0–3 days). One minor neurological complication with complete recovery was observed.

Conclusions: Minimally invasive surgery has the advantage of less tissue damage, less morbidity and a better cosmetic appearance. With newer implants a good correction of the scoliosis can be achieved.