Spinal stabilization from an anterior approach (ALIF, OLIF)

Spinal instability may develop due to various causes, and various conservative treatments can be used for it, but in some cases, improvement may only be achieved by surgery. This involves the surgical implantation of metal fixation devices by our physicians, which contribute to the stability of the spine, and the reduction of the symptoms. Various minimally invasive surgical methods with an anterior approach can be used instead of the conventional spinal stabilization. In every case, it is the physician who decides which method should be used to perform the intervention in the patient.

The function of the spine is complex. It protects the spinal cord and the nerves from injuries, transmits the body weight onto the pelvis, and provides trunk movements within the given stable ranges. The spinal cord and the cauda equina are located in the spinal canal, which is bordered by the vertebral bodies and the series of intervertebral discs from the front, and by the vertebral arches and the intervertebral ligaments from the back. If these functions are compromised – usually in a combined manner –, spinal movements become uneven, and instability develops.

As the result of instability (pathological movements), the nerve and the soft tissue structures of the spine may get injured causing pain. If instability persists for a longer period of time even without producing any symptoms, the narrowing of the spinal canal develops as the consequence of the compensatory mechanisms of the body (thickening and calcification of the ligaments, growth of stabilizing bone spurs), and degenerative processes (intervertebral disc degeneration, joint wear of the facet joints), which produces intense pain because of the compressed nerve structures.

Potential symptoms:

• Pain, which increases on loading, accompanied by numbness.
• The limited range of motion of the spinal segment.
• Disturbed sensation or loss of sensation in some areas of the lower limb.
• Weakness, or muscle paralysis of the muscles or muscle groups of the lower limb.
• Vegetative disorders i.e., bowel and urinary incontinence, and sexual dysfunction.
• Pain avoiding, the so called antalgic body posture.
• Limping.

Spinal fusion surgeries have two goals:

• Decompression: to stop the narrowing which compresses the nerve structures
• Stabilization: To abolish instability with implants.

The advantage of minimally invasive explorative surgeries performed from a frontal approach is that the muscular coat of the spine remains unharmed in most cases, which makes the recovery quicker. Complete or partial removal of the components responsible for the instability of the spine is performed during the surgery, then a spacer is implanted between the neighboring vertebrae, so that the healthy vertebrae will grow together with bony connections, eventually forming a block, and resolving the instability, which produces the pain.

Such surgeries are:

• OLIF: It is a surgery that is performed from a diagonal sideways approach, during which the surgeon uses an already existing anatomical space (peritoneum) through an incision that is made on the left side of the abdomen, so that the operable part of the spine can be accessed.
• ALIF: It is a surgery that is performed from a frontal approach, during which the surgeon reaches the previously mentioned anatomical space through an incision that is made on the lower part of the abdomen.

Depending on the spine disorder, it could occur that the vertebrae need to be secured by screws, which are inserted from the back side through the posterior bony structures of the vertebrae. In this case, the screws are implanted through posterior skin incisions during surgery.

It is important to note that the above surgical techniques cannot be used in everyone. The question of operability depends on the individual anatomical arrangement of the abdominal great vessels and the musculature, the type of the spine disorder, and the amount of abdominal fat tissue. It is the surgeon’s competency to make a decision about operability.