Spinopelvic Fixation

What is Spinopelvic Fixation?

Spinopelvic refers to the area where the pelvis and spine meet. Fixation refers to utilisation of fixation devices such as rods and screws to immobilise a part of the spine and allow healing.

Spinopelvic fixation is a surgical procedure in which the base of the spine is immobilised using rods and screws and accompanied by a fusion procedure. A fusion encourages specific bones to grow together or fuse permanently to form one solid bone. A solid fusion bestows stability to the region. Fixation devices function by holding the spine stable as the bones grow together.

A spinopelvic fixation procedure involves both the lumbar (lower) spine and the sacrum (base of the spine).

Anatomy of the Lumbosacral Spine

The spine is made up of 33 small bones called vertebrae and is known as the spinal column or vertebral column. The vertebrae are protected by spongy vertebral discs that are present in between them and are supported by ligaments that hold them together and surround the underlying spinal cord. The spine can be divided into 4 parts: cervical, thoracic, lumbar, and sacral region. The lumbar spine is composed of the lower 5 vertebrae, numbered L1–L5. The lowest vertebra of the lumbar spine (L5) is connected to the top of the sacrum, which is a triangular bone present at the base of the spine that fits into the two pelvic bones.

Indications for Spinopelvic Fixation Surgery

Lumbosacral dissociation is the main indication for spinopelvic fixation. Lumbosacral dissociation is a high-energy traumatic injury that results in anatomic separation of the vertebral column from the pelvis and is most often associated with neurological deficits as well as other fractures. Fractures of the sacrum also result in spinopelvic dissociation or instability. Spinopelvic fixation helps to achieve complete exclusion of the fractured sacrum from weight-bearing and restore stability to an unstable pelvis. It is recommended for the treatment of conditions such as:

• Scoliotic spine degeneration
• Degenerative spondylolisthesis or spinal stenosis
• Infection of the pelvic joints and bones
• Resection of pelvic tumours requiring bone removal from the sacrum or lumbar vertebrae
• Revision failed fusion and fixation surgery

Preparation for Spinopelvic Fixation Surgery

Pre-procedure preparation for spinopelvic fixation may involve the following steps:

• A thorough examination by your doctor is performed to check for any medical issues that need to be addressed prior to surgery.
• Depending on your medical history, social history, and age, you may need to undergo tests such as blood work and imaging to help detect any abnormalities that could threaten the safety of the procedure.
• You will be asked if you have allergies to medications, anaesthesia, or latex.
• You should inform your doctor of any medications, vitamins, or supplements that you are taking.
• You should refrain from medications or supplements such as blood thinners, aspirin, or anti-inflammatory medicines for 1 to 2 weeks prior to surgery.
• You should not consume any solids or liquids at least 8 hours prior to surgery.
• You will be instructed to shower with an antibacterial soap the morning of surgery to help lower your risk of infection after surgery.
• Arrange for someone to drive you home after surgery.
• A written consent will be obtained from you after the surgical procedure has been explained in detail.

Procedure for Spinopelvic Fixation Surgery

The basic steps involved in the spinopelvic fixation surgery include:

• The procedure will be performed through a posterior approach from the back of the body.
• You will be administered general anaesthesia and placed in a prone position (face down) on the operating table.
• A vertical incision is made over the sacrum and muscles and soft tissues are retracted to expose the lumbosacral area.
• Your surgeon performs the required treatment such as removal of a tumour or bony fragments from the fracture zone.
• Long screws are inserted into sturdy sections of bone in the iliac crest, sacrum, and lumbar spine.
• The screw heads are specifically designed to be fixed with rigid rods.
• The rods work by immobilising the joints and the screws hold the rods firmly in place.
• Your surgeon then performs bone fusion between the top of the sacrum (S1) and the last spinal vertebra (L5).
• The thick sections of bone at the anterior of the spine are commonly the location of this fusion.
• Confirmatory X-rays may be taken to confirm proper alignment as well as fixation and fusion at the lumbosacral area.
• Finally, the retracted muscles and soft tissues are placed in their normal anatomical positions and the incision is sutured.

Postoperative Care and Recovery

In general, postoperative care instructions and recovery after spinopelvic fixation surgery may involve the following:

• You will be transferred to the recovery area where your nurse will closely observe you for any allergic/anaesthetic reactions and monitor your vital signs as you recover. 
• You may need to stay in the hospital for 2 to 3 days before discharge to home.
• You may experience pain, inflammation, and discomfort in the operated area. Pain and anti-inflammatory medications are provided as needed.
• Application of cold and heat therapy on the low back area is also recommended to reduce inflammation and pain.
• Antibiotics are prescribed as needed to address the risk of surgery-related infection.
• Your diet is slowly advanced post surgery. You will start with clear liquids, then progress to having normal solid foods, as tolerated.
• Instructions on surgical site care and bathing will be provided.
• Eating a high-calcium and low-fat diet is strongly recommended to promote healing and a faster recovery.
• Avoid lifting, bending, or twisting your back for the first 6 weeks. Do not lift anything heavier than 5 pounds for the first 2 weeks. Refrain from any strenuous activities such as housework, yard work, or sex for at least a month.
• A corset or brace may be recommended to limit bending and assist with healing of the fused region.
• A physical therapy protocol is recommended to help strengthen low back, pelvic, and leg muscles and optimise their function. Walking is a good exercise and is strongly recommended to improve your endurance.
• Refrain from driving until you are fully fit and receive your doctor’s consent.
• You will be able to resume your normal activities in 2 to 3 weeks but may have certain activity restrictions.
• Complete recovery and return to work vary from patient to patient as it is related to a patient’s overall health status and the type of work one does.
• A periodic follow-up appointment will be scheduled to monitor your progress.

Risks and Complications

Spinopelvic fixation surgery is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as:

• Infection
• Bleeding
• Blood clots
• Anaesthetic reactions
• Hardware failure
• Neurovascular injury
• Persistent pain
• Failure of vertebral fusion

Thoracic Discectomy

The human spine provides support to the body allowing you to stand upright, bend, and twist. The spine can be broadly divided into the cervical, thoracic, and lumbar spine. The thoracic spine lies in the mid-back region between the neck and lower back and is protected by the rib cage.

24 spinal bones called vertebrae are stacked on top of one another to form a spinal column. Between two vertebrae there is a disc of cartilaginous tissue called an intervertebral disc. Intervertebral disc acts as a shock absorber and protects the spine from the strong forces of movement during activities such as jumping, running, and lifting.

Wear and tear can occur in the disc with age and may cause the soft spongy tissue in the centre of the disc to squeeze (herniate) from a tear on the side of the disc. Disc herniation may also occur due to an injury such as during a car accident or a fall, a sudden and forceful twist of the mid-back or disease of the thoracic spine such as Scheuermann's disease.

The herniated disc protrudes into the hollow tube of the spinal column called the spinal canal and directly pushes against the spinal cord passing through the spinal column. This can injure the spinal cord. Herniated discs can also block blood flow from the one and only blood vessel going to the front of the spinal cord in the thoracic region of the spine causing nerve tissues in the spinal cord to die.

Symptoms of thoracic disc herniation vary depending on the position and size of the disc herniation; nerve irritation or nerve injury; and damage to the spinal cord. Symptoms may include mid-back pain; pain around the front of the chest that may mimic heart problems; groin pain, numbness, and weakness in the legs and arms. It may even affect bowel and bladder function.

Usually, thoracic disc herniation is treated conservatively with rest, back brace, medication, and physical therapy. Surgery is considered when long term conservative treatment does not relieve pain or the condition is rapidly getting worse or is affecting the spinal cord.

How is the surgery performed?

The goal of the surgery is to remove all or part of the herniated disc pressing on the nerve root or spinal cord and is called discectomy. Thoracic discectomy can be performed either through the anterior approach (front side) or posterolateral approach (behind and to the side).
 
Anterior approach: This approach usually involves open thoracotomy in which the herniated disc is accessed through the chest cavity. An alternative to open thoracotomy is Video-Assisted Thoracic Surgery (VATS). VATS is a minimally invasive surgery that is done through several small incisions and involves the use of a thoracoscope, a surgical tool with a tiny camera. Thoracoscope is inserted into the side of the thorax through a small incision to provide real images of the surgical area on a TV screen. These images guide the surgeon to remove the herniated disc using instruments inserted through other small incisions. VATS is minimally invasive and results in quicker recovery than open thoracotomy.

Posterolateral approach: This approach is also called as costotransversectomy. The herniated disc is accessed through an incision on the back of the spine. A window through the bones that cover the herniated disc is created by removing a small part of the rib where it connects to the spine (Costo means rib) and transverse process (a small bone attached to the spine). The discectomy is then performed with small instruments.