A spinal fusion removes the flexible elements of the spine, creating a solid block of bone throughout the fused area of the curve. This, in most cases, is performed with the addition of an instrumentation system of rods, hooks, wires, and/or screws. The instrumentation system is used to correct the curvature of the spine as much as possible, as well as to maintain stability of the spine in the postoperative period while solidification of the fusion occurs. The surgical approach to the spine can be either through an incision on the back (posterior) or through an incision in the side (anterior).
When doing a posterior spinal fusion the spinous processes, lamina, and transverse processes of the spine are exposed. It is to these elements of the vertebra that the hooks, wires, or screws are placed to provide fixation of the rod to the spine (Figure 8a, b, c). Bone graft is applied to the exposed bony surfaces of the spine, which allow these vertebrae to subsequently grow together or fuse with bone connecting each of the vertebra to one another.
In some curve patterns a similar correction and fusion can be performed via an anterior approach. This involves an incision on the side of the chest or abdomen to expose the front or anterior part of the spine. It is in this area where the vertebral bodies and discs are located. Fusion in this area involves removal of the soft disc material between the vertebrae and replacement of this tissue with bone graft, which will allow bony union or fusion between the adjacent vertebral bodies. Instrumentation systems that are applied anteriorly generally involve fixation to the vertebral body with a screw and connection between the screws with a rod system (Figure 9a, b). This anterior approach can be done in the thoracic, thoracolumbar, or lumbar regions, depending on the curve pattern.
There are times when both an anterior and posterior approach to the spine is required. In circumstances when the curve is extremely rigid or the patient quite young (less than 10-12 years), approaches to both the front and back of the spine may be required. Much of the growth potential in the spine is located in the vertebral body adjacent to the disc. This growth center is responsible for vertebral body growth and causes much of the progression of the curvature that occurs during spinal growth. Therefore, anterior fusion is useful at decreasing or stopping the anterior vertebral body growth. Therefore, in young patients, anterior fusion is recommended. The anterior fusion may be required in combination with a posterior fusion and instrumentation if the curve cannot be instrumented anteriorly. When a curve is particularly large and rigid, correction may be inadequate if posterior instrumentation is done without removal of the anterior discs. Removal of the anterior discs in such a case increases the flexibility of the spine and allows for better correction of the deformity by the instrumentation system.
Minimally invasive methods are also available for approach to the anterior aspects of the spine. In the chest this is done with what is known as a thoracoscopic approach. The endoscopic approach utilizes small incisions and video technology to view the spine. Specialized instruments are used to perform disc removal, instrumentation and fusion (Figure 10a). In some cases a posterior fusion is also required to perform the instrumentation portion of the procedure, although some curves can now be corrected with the endoscopic approach alone.
Spinal Growth Tethering Surgery
A new procedure being performed at Rady Children’s is spinal growth tethering surgery, in which a small rope-like cord is attached to the vertebrae along the side of the spinal column to asymmetrically alter spinal growth. Unlike spinal fusion, the surgery corrects the curvature while maintaining the mobility of the treated areas of the spine. Peter Newton, M.D., performs spinal tethering surgery in scoliosis patients who have two to three years of remaining growth with curves of more than 45 degrees in the chest region of the spine.
Patients from across the country have come to Rady Children’s for this procedure, including a triathlete from Kansas City; her curvature was corrected (see Figures 9 a & b), and she continues to win races and compete at a very high level.
Magnetic Growing Rod Surgery
For patients with early onset scoliosis, Rady Children’s offers a groundbreaking procedure using adjustable magnetic growing rods. The rods are attached to one or both sides of the spine, and following surgery, they can be lengthened non-invasively as the child grows using an external remote controller. Rare earth magnets inside the rods communicate with the external remote controller (ERC), allowing physicians to modify the length of the rods without surgery. Rady Children’s performed the first surgeries in the United States using this revolutionary technology. Learn more.
What are the risks of surgery?
With any surgical procedure, the risks and benefits of the procedure must be carefully assessed for each individual patient. The risk to the patient of not having surgery must also be addressed. In the case of progressive scoliosis, the risks of not having surgery if brace treatment has failed or is not indicated have been suggested above. These involve progressive deformity of the trunk with potential imbalance and offset between the trunk and pelvis when in an upright position. In addition, with thoracic curves, risk to the heart and lung function develops when curves reach 80-90°. This results from compression of the lung within the deformed chest cavity, which makes it difficult for the heart to pump blood through the compressed lung. Most cases of scoliosis are treated prior to curves reaching such a magnitude.
The specific surgical risks are dependent on multiple factors, including the general health of the patient, any underlying medical disorders, as well as the type of surgery that is required. In general, with all operations around the spine there are potential complications relating to the anesthesia, as well as risks of bleeding and wound infection. With anticipation preoperatively, blood loss can be managed by one of several means, depending on the anticipated magnitude of the blood loss. These include pre-donation of the patient’s blood (autologous) or of blood from family members or friends (donor specific). An additional option involves the use of banked blood components. Intraoperative blood conservation techniques can be utilized with either use of hemodilution or blood salvage with recirculation methods to minimize need for other forms of blood replacement.
Additional potential intraoperative complications relate to neurologic injury. Surgery involving the spine places the neural elements of the spinal cord and nerve roots at some risk for injury. Injury to these structures may result in a spectrum of disability that spans from mild numbness to loss of bowel or bladder function to complete paralysis below the area of injury. The risk of spinal cord injury can be minimized, although not completely eliminated, by use of sophisticated spinal cord monitoring systems. This spinal cord monitoring is performed during the exposure and correction of the spinal deformity and monitors electrical function of the spinal cord throughout the surgical procedure. When indicated a “wake-up” test may be utilized to ensure normal neurologic function. This involves decreasing the level of anesthesia, after completion of the deformity correction, to the point that the patient is able to hear and follow commands. The patient is instructed to move the lower extremities to confirm that voluntary motor function remains present. If normal function is observed, the procedure is completed with wound closure. If spinal cord functional problems are noted with spinal cord monitoring and confirmed by abnormality appreciated on a wake-up test, removal or adjustment of the instrumentation may be required. This decreases the stress applied to the spinal cord by the instrumentation system, improving the likelihood of neurological recovery.
Postoperatively, complications may also arise. These include development of a wound infection, pulmonary difficulties, as well as problems associated with the hardware system and fusion. Postoperative wound infections occur in roughly 1% of patients. Measures taken to minimize this risk include the use of antibiotics before, during, and after the operation. There are risk factors that increase the likelihood of wound infection, which include poor nutritional status, history of urinary tract infections and revision surgery. In most cases wound infection can be managed by a return to the operating room with cleaning of the wound and closure of the wound over drains, along with prolonged antibiotic use. In rare cases there is a delayed presentation of infection, which may come as late as 1–2 years postoperatively. In these cases, generally the treatment is cleaning of the wound and removal of the hardware. These delayed infections can be successfully managed with hardware removal and antibiotics.
Complications related to the instrumentation system and fusion are possible. In occasional instances, there is loss of fixation of the rod system to the spine, resulting in some loss of correction. This may require revision of the instrumentation system with replacement of hardware and reattachment to the spine. Additionally, there may be difficulties in obtaining fusion at each of the involved levels of the spine. If an area of nonunion (lack of fusion) or pseudarthrosis develops, there may eventually be breakage of the rod system. In many circumstances this does not cause further problems. However, in some cases it may require revision of the instrumentation system if there is pain or evidence of curve progression.
What is the recovery period?
The recovery after scoliosis surgery is variable, depending on the nature of the surgery performed. In general, after having 2–8 or more hours of surgery, time is spent initially in the Recovery Room. In this area the patient is allowed to wake up from the anesthesia and regain voluntary breathing. There are times when it is necessary to maintain respiratory support on a ventilator for one or more days following this surgery. If this is required or there are other indications to do so, the initial postoperative period may be spent in an Intensive Care Unit. This allows for ventilatory support of the respiratory system, as well as close monitoring of the cardiovascular system.
There are several options for managing pain in the initial postoperative period. These include intravenous narcotic medicines, such as morphine or Demerol. Once the patient is drinking/eating, the transition from IV to oral pain medication will be initiated. The intravenous route is convenient and can be delivered either by the nurse or with a patient-controlled anesthesia (PCA) system. This allows the patient some control over the timing of administration of pain medication.
In the initial postoperative period, there may be several tubes in place. The tubes will be placed while the patient is under anesthesia. These may include:
- A nasogastric tube to drain the stomach contents, the tube will be in place while the intestines “wake up” or recover from the effects of anesthesia usually 2-3 days. After the intestines start to work again (bowel sounds and flatus present), the patient may then start to drink and eat again. Generally the diet is advanced gradually, starting with liquids and progressing to solid food.
- There will be a bladder (urinary) catheter inserted during surgery.
- Surgical drains may be placed in the back to allow for drainage of fluids.
- If surgery in the chest area is performed, a chest tube will be required to drain fluid from the chest (thoracic cavity).
- Intravenous lines will be in place to administer both medications and fluids. There may also be an arterial line for the same purpose, as well as to assist with blood pressure monitoring.
These monitoring lines and drainage tubes will be removed sequentially in the days following surgery when they are no longer necessary.
In the first day or two following surgery, there is little physical activity required of the patient, though the nurses will be repositioning the patient in bed every 1–4 hours. There will then be a gradual increase in activity/mobilization, generally starting with sitting, then standing, then resuming walking. The timing and rate of the increase in activity will vary, depending on the type of surgery done. Depending on the patient and/or the type of surgery performed, some patients may need to wear a brace for 3-4 months after surgery. The brace provides external support to the trunk while the fusion is healing. This brace comes in various forms and the form will depend on the patient and type of surgery performed. This brace is to be worn at all times except when in bed. This brace will be fit and provided to you prior to discharge from the hospital.
In general, requirements for being discharged from the hospital following surgery include:
- Tolerating oral liquids and food.
- Comfortable on oral pain medications.
- No fevers.
- Ability to ambulate (if ambulating prior to surgery)
- Able to urinate and have bowel movement.
After discharge from the hospital to home it usually takes several weeks for pain to completely resolve and in general, a gradual weaning from narcotics to Tylenol takes place naturally. It is not uncommon for patients to be comfortable on Tylenol during the day and need narcotics at night for comfort during this weaning process.
In general, school age children/teens are ready to return to school 3–4 weeks after surgery, depending on the child and the type of surgery. Some children tolerate a return to school for just half days initially, but we encourage returning as soon as possible to a “normal” schedule.
Physical activity and sports are restricted after surgery for 6–12 months, depending on the type of surgery. We encourage children to begin walking for exercise (if child is ambulating prior to surgery) at the time of discharge. Bending, twisting, and lifting activities are to be avoided. At each follow-up visit, x-rays will be done to access healing of the fusion. This will allow your surgeon to make decisions regarding easing off on both bracing and activity restrictions. As healing occurs, brace wear will be discontinued, and permitted activities may be increased. Generally at 1 year following surgery, children may participate in all activities without restriction.