PEDICLE SUBTRACTION OSTEOTOMY

Questions and Answers

Although the Thought of Removing Bone Seems Severe, Here’s Why it Works

A person’s spine always maintains a curve.  As an example, your upper back bends slightly forward, and your lower back possesses a small sway (called lordosis) (known as kyphosis). These curves look exactly alike and appear as a perfect mirror image of each other. However, they work as a unit to maintain the alignment of your head and pelvis. The flat back condition might result from losing our natural curve. Kyphosis, or a permanent slump, can develop if we gain too much curvature. Despite being opposed, these issues refer to sagittal imbalance. Simply put, this describes how we lean either forward (chin-on-chest syndrome) or backward. The PSO corrects this by making a hinge on the spine’s rear side… and then shutting it. Closing the gap results in the lumbar spine’s lower back gaining lordosis and the thoracic spine’s upper back losing kyphosis.

Pedicle Subtraction Osteotomy (PSO) Treats the following Conditions

Flatback Syndrome

• Condition: Flatback syndrome occurs when the natural curvature (lordosis) of the lumbar spine is lost, causing the spine to become abnormally straight. This condition can lead to significant pain and difficulty standing upright, as the body compensates by leaning forward.
• How PSO Helps: PSO restores the lordotic curve by allowing for a dramatic correction, improving the patient’s ability to stand and walk without leaning forward.

Severe Kyphosis

• Condition: Kyphosis is an excessive outward curvature of the spine, resulting in a hunchback or rounded appearance. Severe cases, particularly in the thoracolumbar or lumbar regions, can be debilitating and painful.
• How PSO Helps: PSO is used to reduce the kyphotic curve by realigning the spine, offering significant improvement in posture and reducing pain.

Post-Traumatic or Degenerative Deformities

• Condition: Trauma or degenerative changes such as arthritis or disc degeneration can lead to spinal deformities, including vertebral collapse or misalignment.
• How PSO Helps: In cases where other treatments are insufficient, PSO provides a structural solution by removing damaged or deformed bone and realigning the spine.

Revision Surgery for Failed Spinal Fusions

• Condition: Previous spinal fusion surgeries that did not achieve the desired alignment, or cases where adjacent segments have degenerated, may result in imbalance or deformity.
• How PSO Helps: PSO is often used in complex revision surgeries to correct sagittal imbalance and achieve proper alignment.

Spondylitis with Severe Spinal Deformity

• Condition: Ankylosing spondylitis is a type of arthritis that causes chronic inflammation of the spine, leading to fusion and severe deformity in advanced cases. This can result in a stooped posture with difficulty looking straight ahead.
• How PSO Helps: PSO can correct the deformity by creating the necessary space to realign the spine, improving posture and quality of life for patients with ankylosing spondylitis.

PSO is a highly effective surgical option for correcting complex and rigid spinal deformities where more conservative methods or less invasive surgeries may not provide sufficient correction. However, it is a challenging procedure and is typically reserved for severe cases where non-surgical treatments have failed or where significant structural correction is needed.

The Procedure for Pedicle Subtraction Osteotomy

Ankylosing spondylitis sufferers were the target audience for the first description of PSO. The benefit includes the treatment of kyphosis without extending the anterior column (and potentially stretching and injuring vascular structures). Additionally, it eliminates the morbidity linked to the anterior approach. Our surgeons address the spine from the back, and pedicle instrumentation gets applied across the areas required for deformity stabilization and repair. The surgeon removes the spinous process, lamina, and facet joints to expose the designated vertebrae. The indicated vertebra gets exposed and the spinous process, lamina, and facet joints get removed.

The upper and lower levels of lamina 1 also get removed to prevent twisting of the neural structures after modification. Next, resect the pedicle at the affected level to the base of the posterior vertebra, preserving the existing nerve root. The surgeon places a temporary rod for stabilization before excising the anterior column. Subperiosteal dissection of the vertebral body takes place and a retractor gets inserted. The amount of bone required for the planned correction gets removed with the appropriate instrument.

The surgeon uses a temporary rod to stabilize the spine during deformity correction, and the surgeon examines the dura mater to ensure that neurological compression does not exist. Neuromonitoring continues to ensure that no new neurological changes occur.  The surgeon completes the procedure by inserting the final instrumentation and completing the bone graft fusion.

When Does Pedicle Subtraction Osteotomy Occur?

A normal spine contains a few moderate curves that, when seen from the side, balance one another and place the body’s center of gravity over the pelvis. Sagittal balance describes this alignment. The causes of sagittal imbalance can point to conditions that move the body’s center of gravity too far in front of the pelvis and include hyper-kyphosis, ankylosing spondylitis, andflatback syndrome. Pedicle subtraction osteotomy addresses sagittal imbalance. Viewed from behind, a normal spine looks straight.

Curvature of the Spine

Different types of spine curvature can affect individuals of various age groups. Understanding these types can help in identifying the right treatment approach.

• Scoliosis: Scoliosis appears as a side-to-side curve that becomes very apparent from behind. Occasionally, a pedicle subtraction osteotomy might treat a little degree of scoliosis. Doctors can measure the spine’s curve, which will provide these experts with the severity of the curve. For instance, scoliosis, a side-to-side curve, maintains a curve of at least 10 degrees.
• Hyperkyphosis: This condition involves an excessive forward curve of the spine. Average spine kyphosis ranges from 20 to 40 degrees; a kyphosis of 70 degrees or more may require surgery.
• Flatback Syndrome: This condition results in a reduced normal curvature of the spine, leading to a flat appearance and potential back pain.
• Ankylosing Spondylitis: A form of arthritis that primarily affects the spine, leading to a hunched-forward posture due to inflammation.

Scoliosis in Different Age Groups

Scoliosis can manifest differently depending on the age of the individual:

• Children: Scoliosis in children can often be detected early through regular check-ups and can sometimes correct itself as the child grows.
• Teens: This is the age group most commonly affected by scoliosis, often requiring braces or other interventions to prevent progression.
• Adults: Adult scoliosis can be a continuation from adolescence or develop due to degenerative changes in the spine. Treatment often focuses on pain management and maintaining mobility.

Understanding these different types of spine curvature and their implications can guide both patients and healthcare providers in choosing the most effective treatment options, including surgical interventions like pedicle subtraction osteotomy.

Pedicle Subtraction Procedure Performed

A pedicle removal osteotomy occurs when the patient goes under general anesthesia. Spinal cord monitoring techniques and Motor Evoked Potentials measure nerve electrical activity and help ensure spinal safety during surgery. Once the patient becomes unconscious, they get placed face down on a special folding operating table. Following a central back incision, the bones of the spinal column become visible. Following that, the surgeon inserts screws into the vertebrae above and below the targeted region.

Screws get placed in the pedicles, the thick columns of bone that join the back and front of the vertebra, giving them the name “pedicle screws.” The rods will keep the spine in place while it heals. Next, the surgeon removes a protrusion called an appendage from behind the target vertebra. The surgeon hollows out the space under the pedicle of the target vertebra and removes the pedicle. The surgeon then widens the space and creates a wedge-shaped cavity in the vertebrae.

Once completed, the wedge-shaped top and bottom get placed together. This closes the wedge and corrects the deformity by about 30 degrees. The surgeon gradually unfolds the specialized operating table from an inverted “V” shape to a flatter position until the bone surfaces touch and the wedge closes. To keep the spine in place while it heals, rods get inserted into the pedicle screws. The upper and lower wedge’s bone surfaces will fuse into one solid bone as they develop together, giving the vertebra long-lasting strength and stability.

Potential Complications in Rod-Screw Systems for Pedicle Screw Fixation

When utilizing rod-screw systems for pedicle screw fixation in spinal surgeries, several potential complications can arise. Understanding these risks is crucial for medical practitioners and patients alike.

Screw Breakage and Rod Loosening

Traditional rigid rods used to stabilize the spine can cause issues, particularly in areas of high flexibility like the lower back. The rigidity can concentrate stress at the point where the rod meets the screw. Over time, this stress may lead to screw breakage, where the screw’s head detaches from its threaded body, or cause the connecting rod to loosen. Such complications can result in instability and increased pain at the surgical site.

Septic Loosening

Another risk involves the potential for low-grade infections at the site where the pedicle screws are inserted. Poor handling during surgery can introduce bacteria, leading to infection, swelling, and eventual loosening of the screw. This condition often necessitates the removal of the infected screw to alleviate pain and resolve the infection.

Pulmonary Embolism

During the surgical procedure, there is a risk of fat or bone marrow entering the bloodstream and causing a blockage in the lung’s blood vessels, a condition known as a pulmonary embolism. This complication can be particularly dangerous, as it hampers blood flow and can lead to severe respiratory issues. The use of pedicle screws has been noted to increase the risk of such embolisms.

Cerebrospinal Fluid Leak

Incorrect placement of pedicle screws can puncture the dural sac, the protective membrane surrounding the spinal cord. This can result in a leak of cerebrospinal fluid. This is characterized by low spinal fluid pressure in the brain, or bleeding within the skull. Both scenarios necessitate prompt medical intervention to prevent long-term damage.

By being aware of these potential complications, surgeons can take preventative measures to minimize risks and ensure better outcomes for their patients.

How Should I Prepare for this Procedure?

It’s crucial to cease using tobacco products before any deformity repair operation. The effects of nicotine on bone fusion and surgical results remain quite negative. Speak to your neurosurgeon if you use cigarettes or smoke now about stopping. Patients or parents of patients should make sure they learn the intended outcomes of the operation, the potential dangers, and what to anticipate from the healing process. Speak with the surgeon treating you or your child if questions arise concerning the treatment or the healing process. You should write down any questions you or your child want answered and then bring the list with you to your visits.

Tell your doctor about any drugs or dietary supplements you or the patient take, especially those that might thin your blood, such as aspirin. Before your surgery, your doctor may advise you or the patient to cease taking certain drugs. Before the procedure, list all drugs you take to make it simpler. If you or the patient possess a latex, food, or medicine allergy, please let your doctor know (some surgical gloves contain latex). Remove any nail paint or acrylic nails the day before surgery, skip makeup, and take off all jewelry. Bring any necessary materials, including a toothbrush, toothpaste, and dentures. Upon registration, the hospital employee will place an ID bracelet on your wrist that will contain your name, birthday, and the name of the surgeon.

Pedicle Subtraction Osteotomy’s Benefits and Drawbacks

Although doctors consider pedicle subtraction osteotomy as a difficult spinal reconstruction with risks, it offers beneficial treatment for severe kyphosis. For example, infection, neurologic damage, dura rupture, instrumentation failure, non-union, chronic pain, DVT, PE, chronic discomfort, and the potential for revision surgery outline a few of these. Although every patient appears differently, the only way to fully understand the risks and advantages of having this surgery occurs when the doctor and patient address each condition and conduct a thorough assessment.  All of our doctors at the Southwest Scoliosis and Spine Institute maintain advanced fellowships and possess the knowledge skills and abilities of experts when it comes to spine health.

Pedicle screws and rods can be removed after a successful spinal fusion. Once the bone graft has integrated and the vertebrae are stable, these hardware components are often no longer necessary for maintaining spinal alignment. However, most surgeons advise against removal unless the screws and rods are causing discomfort or other issues for the patient. The removal process would involve an additional surgery, which carries its own set of risks and considerations.

Why Come to the Southwest Scoliosis and Spine Institute?

The Southwest Scoliosis and Spine Institute specializes in comprehensive care for adults, children, and adolescents with Spine Conditions.  There are several reasons why patients with spine problems should consider coming to this center:

• Expertise: The team includes specialists with extensive experience in treating Spine conditions.
• Multidisciplinary approach: The team of specialists works together to provide a comprehensive treatment plan that addresses all aspects of the patient’s condition.
• They work closely with other specialists such as radiologists, physical therapists, and rehabilitation specialists to ensure that the patient receives the best possible care.
• Experience with adults, children, and adolescents: The surgeons treat children and adolescents and are aware of their growth plates.
• Experience in the latest surgical techniques: The doctors maintain up-to-date training with the latest surgical techniques for treating spine conditions and using minimally invasive surgical procedures, which can lead to faster recovery times and less pain for the patient.
• Follow-up care: The center provides follow-up care to ensure that the patient continues to recover as quickly as possible.

Conclusion

Overall, the Southwest Scoliosis and Spine Institute, with offices in Dallas, Plano, and Frisco, Texas, offers comprehensive care for adults and children with spine conditions.  We provide the expertise, knowledge, skills, and abilities that can provide a positive outcome for patients with spinal medical conditions. As spine experts, we invite you to make an appointment with us to treat your spinal condition.  We have appointments within 24 hours.

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National Institute of Health: Pedicle Subtraction Osteotomy