Instrumented Anterior Cervical Discectomy, Fusion (ACDF)

Decompression neck surgery to remove pressure on nerves from disc herniations

Anterior cervical discectomy with fusion (ACDF) is a common surgical treatment for spinal disc herniations in the neck. A disc herniates when the outer portion of the disc ruptures and some of the softer disc nucleus material squeezes out. The herniated disc pushes against the spinal cord or spinal nerves and tends to cause pain in the neck or arms. Removing the ruptured disc alleviates pressure on the nerves or spinal cord, which usually relieves the pain.

Spine anatomy

The spine, or backbone, is the center of support for the upper body. This column of bones and cartilage extends from the base of our skull to the pelvis, enclosing and protecting the spinal cord. Ligaments and tendons and large muscles connect to the spine, while highly sensitive nerves extend outward from the spinal cord.

A healthy spine is both highly flexible and very strong. Its strength holds up our head and shoulders and supports our upper body. It allows us to stand up straight. The flexibility of the spine enables us to bend and twist.

Vertebrae

The spine is not one long rigid bone. It consists of 24 small bones called vertebrae that are stacked in a column from the pelvis to the base of our skull. These bones connect to create a canal that protects the spinal cord.

The vertebrae are divided into four regions. From top to bottom, these are:

  • The cervical spine (the neck) – the first seven vertebrae located just below the skull
  • The thoracic spine – the 12 vertebrae of the upper back
  • The lumbar spine – the five vertebrae of the lower back
  • The sacral spine – composed of a triangular structure called the sacrum (five individual vertebrae that fuse together between the age of 18 and 30) and the coccyx (commonly called the tailbone and composed of three to five individual vertebrae, some of which may fuse together in adulthood)

Image: Graphic of spine anatomy with segments and vertebral structures labeled.

The curves of the spine

The spine is not perfectly straight; it has natural curves. If you were looking at the spine from the side, you would see that it is curved like an elongated 'S'. These natural curves are very important. When properly maintained, they give the spine full mobility and provide stability for the backbone and surrounding trunk. Good posture is important to maintain the health of our spine.

Spinal cord and nerves

The spinal cord is a cylinder of nerve tissue. Roughly the thickness of a finger, it extends from the skull to the lower back, traveling through the middle part of each stacked vertebra, called the central canal. Nerves branch out from the spinal cord through openings in the vertebrae and carry messages between the brain and the muscles.

Spinal discs

Structures called intervertebral discs are located between each vertebrae. They are flat and round, and about half an inch thick. Their main purpose is to provide shock absorption and allow mobility between the vertebrae. The structure of a spinal disc can be likened to that of a jelly doughnut. It has an outer ring of firm, spongy, malleable material and an inner core composed of a jelly-like substance.

A herniated disc is a common condition that affects these soft tissues. A disc herniation (sometimes called a "slipped disc") occurs when a portion of a disc's inner core bulges or ruptures through the outer ring, putting pressure on a spinal nerve. This may cause low back pain and/or leg pain – such as that associated with sciatica – leg weakness, leg numbness, cauda equina syndrome and other problems.

Illustrations of healthy spinal disc and bulging, herniated disc.
Illustrations of the axial (overhead) view of a healthy disc and a herniated disc putting pressure on a spinal nerve.

Spinal musculature

The spine is supported and controlled by several layers of muscles that perform different actions, yet work together in a harmonious fashion to support the spine, hold the body upright and allow the trunk to move, twist and bend.

Long and thick muscles span much of the back and function like guide wires, protecting the spine from excessive and sudden movement.

Deep and thinner muscles connect from the rib cage to the pelvis and hips. Together, these muscle groups act as a natural corset to provide stability and a foundation from which the hips and pelvis can derive power. This is known as core musculature.

 

Animation: Anterior cervical discectomy with fusion (ACDF)

This animation provides an inside look into an instrumented anterior cervical discectomy with fusion (ACDF), in which a portion of a ruptured spinal disc in the neck is removed to remove pressure on nerves caused by a herniated disc. A bone graft is usually inserted with instrumentation to keep the disc space at a normal height and fuse the vertebrae above and below the removed disc.

 

How an ACDF spine surgery is performed

Incision

An incision is made to one side on the front of the neck. Through this incision, exposure is provided to the front of the cervical spine. The herniated disc that is causing pressure on the spinal nerve is located between vertebrae.

Excision

Surgical instruments are used to remove a portion of the herniated disc, which alleviates pressure on the nerve. After disc material is removed, a bone graft is cut to the correct size and placed in between the vertebrae to add stability.

Stabilization

A metal plate is placed over the bone graft, and two holes are drilled in each vertebra. Four screws are placed through the plate to secure the plate to the vertebra. The metal plate provides additional support while the bone graft grows in place, fusing the vertebrae. A bone graft is usually inserted with instrumentation to keep the disc space at a normal height and fuse the vertebrae above and below the removed disc.

Closure and recovery for ACDF spine surgery

The incision is closed and dressed to complete the surgery. Some patients require a cervical collar for a short period of time after surgery. Most patients notice rapid improvement of their arm pain.

 

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