Definition & Overview
A percutaneous screw removal refers to the procedure that removes the pedicle screw, which is used as an adjunctive treatment for spinal injuries. This is usually combined with spinal fusion surgery, with the screws providing added structural support and preventing unnecessary movement while the spine segments are being fused together. The screws are typically placed in two or three spine segments and are connected by a rod. In some cases, however, the screw has to be removed. In such cases, the procedure can be performed using percutaneous technique rather than open surgery.
In surgery, the percutaneous technique means that the procedure, which requires access to the inner organs, is performed through a needle puncture instead of an open incision. The word “percutaneous” literally means “through the skin”. This minimally invasive technique is associated with fewer risks and is deemed safer compared to the traditional open surgery technique. Thus, it is the surgical technique of choice in cases where a pedicle screw has to be removed.
Who Should Undergo and Expected Results
The procedure is for patients who previously had a pedicle screw implanted. Pedicle screws, also known as bone screws, have been in use in spinal surgery since the 1960s. They are stem-like tools implanted into a vertebral pedicle and connected to one another by special spinal rods. They support the spine and keeps it from moving, increasing the patient’s chances of a successful spinal fusion surgery as well as preventing any pain caused by unnecessary vertebral movement. Nowadays, the standard type of pedicle screw in use is called polyaxial pedicle screw, which is made of titanium and resistant to corrosion and compatible with MRI.
Although more commonly used in the lumbar spine, pedicle screws are also used to treat problems affecting the thoracic and sacral spine. The use of screws and rods is believed to shorten the recovery period following a spinal fusion procedure.
Medical conditions and injuries that may require spinal fusion, or more specifically, pedicle screw insertion (and possibly, removal), as part of treatment include:
- Spinal deformities
- Weak spine
- Spinal infections
- Spinal tumours
- Spinal fractures
- Acute Jones fracture
- Traumatic injury to the spine
- Lumbar degenerative disc disease
Lumber spondylolisthesis, either isthmic, degenerative, or post-laminectomy
Pedicle screws often need to be removed due to complications arising from the insertion procedure or when the body treats the screws as a foreign material. Complications that can trigger a screw removal include:
- Tissue irritation
- Rod and screw breakage, which occurs in about 1 out of every 1,000 screw placements
- Nerve root damage
While pedicle screw removal can be performed through the traditional open technique, the percutaneous version of the procedure is increasing in popularity mainly because it reduces the risks of the open technique, such as blood loss, muscle denervation, ischemia, infection, pain, impairment, allergic reactions to anaesthesia, and increased intramuscular pressure. This high risk of complications is due to the fact that a traditional open spinal surgery not only requires an open incision but also the removal of an extensive amount of muscles and other tissues to access the spinal surface.
After a successful percutaneous screw removal, the patient’s normal spine should be restored, as long as no facet joints were damaged or affected during the screw insertion.
How is the Procedure Performed?
During a percutaneous screw removal, the surgeon gains access to the position of the screw by inserting a needle through the skin, followed by a flexible guide wire that creates a pathway through the skin. The surgeon then inserts a catheter and passes special surgical tools through it to reach the area where the screw was implanted, using sonography as his guide. The tools allow the surgeon to remove the screw, which is then passed through the catheter on its way out.
After the procedure, the small hole made by the needle through the skin seals quickly and thus heals very fast, especially in comparison to an open incision.
A percutaneous screw removal procedure does not require the patient to stay in the hospital and can be performed on an outpatient basis. Also, since only a small skin hole is required, the patient will only require milder doses of anaesthesia, reducing the risk of suffering from serious anaesthesia-related complications.
Possible Risks and Complications
While the insertion of pedicle screws is associated with a number of risks and potential complications, percutaneous screw removal is relatively safer. In fact, most cases are attributed to complications arising from the insertion of the screws. When the complications affect the lower spinal segments, the pedicle screws need to be removed.
Gruber M., Starkweather K., Healy W. III, Haralabatos S. “Percutaneous Screw Removal in Slipped Upper Femoral Epiphysis. J Bone Joint Surg. (Br) 1996;78-B:137-9. http://www.bjj.boneandjoint.org.uk/content/jbjsbr/78-B/1/137.full.pdf
Cappuccio M., De lure F., Amendola L., Martucci A. (2015). Vertebral body compression fracture after percutaneous pedicle screw removal in a young man.” J Orthop Traumatol. 2015 Dec; 16(4): 343-345. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4633417/