In this study, an independent spine surgeon reviewed the records of patients who had a spinal fusion using pedicle screws for scoliosis. Patient charts and imaging studies (X-rays and/or CT scans) were used. All 115 patients were treated at the same spine surgery clinic in Italy.
Everyone had a diagnosis of thoracic scoliosis. This is a curvature of the mid-spine. Over 1,000 screws were used by three surgeons over a period of three years. Complications such as fever, screw misplacement, and fractures were recorded. Wound infection, neurologic problems, and loosening of the screws were other problems that developed in some patients.
The authors describe the surgical technique used to place the screws in the spine. A mini-laminotomy was performed. Only part of the lamina was removed. The lamina is part of the curved arch of bone in the vertebra that forms the spinal canal. A special surgical tool called a spatula was used to feel inside the spinal canal and find the right place for the screw.
Patients were followed for up to five years. Any screw-related complications were reported during that time. Screw misplacement was the biggest problem. Patients with the most severe curves were more likely to have this complication. Only one out of the 13 patients with this problem had any symptoms.
Misplaced screws were only removed if they presented a potential risk for the patient. The patients at greatest risk were those whose screws were closest to the aorta. The aorta is the main blood vessel leaving the heart. It takes blood to the brain and rest of the body. Most malpositioned screws can be left where they are without problems.
The authors conclude that the mini-laminotomy method of screw placement for thoracic scoliosis increased the safety of the procedure. Despite some complications, there were fewer problems than with the open-laminotomy procedure. The mini-laminotomy approach does require extra care and caution by the surgeon but has good results.