Spinal pathology is incredibly varied and requires a wide range of techniques and a deep understanding of this critical structure's bony and neural anatomy. The spinal canal, comprised of the cervical, thoracic, and lumber vertebrae, houses the spinal cord from the head down to L1 in most people. Bony anatomy is also intricate. Each vertebra is constructed like a tin can -most of the strength is in the outer surface of the vertebrae and consists of cortical bone. The inner medullary bone is soft and houses the hematopoietic systems - the blood stem cells that can become red blood cells, white blood cells, or platelets.
Surgeons develop approaches to spinal pathology to achieve spinal stability with neural decompression with minimal collateral damage. To this end, several different spinal approaches to access the spine can be employed, including TLIF, PLIF, OLIF, XLIF, and ALIF. Here's a brief explanation of each approach:
1. TLIF (Transforaminal Lumbar Interbody Fusion): TLIF is a minimally invasive surgical technique for treating degenerative disc disease, spinal stenosis, or spondylolisthesis. The approach involves accessing the spine through a small incision from the back. The damaged disc is removed, and bone graft material is inserted into the disc space. Pedicle screws and rods are then used to stabilize the spine while promoting fusion.
2. PLIF (Posterior Lumbar Interbody Fusion): PLIF is similar to TLIF but involves accessing the spine from a more mid-line angle. The damaged disc is removed, and bone graft material is inserted into the disc space. Pedicle screws and rods are used to provide stabilization and fusion.
3. OLIF (Oblique Lumbar Interbody Fusion): OLIF is a minimally invasive approach that accesses the spine through a small incision on the patient's side. This approach allows direct access to the intervertebral disc and preserves the back muscles. It is commonly used to treat degenerative disc disease or spinal instability.
4. XLIF (eXtreme Lateral Interbody Fusion): XLIF is a minimally invasive approach where the spine is accessed through the patient's side. This approach avoids the need to retract or disturb critical back muscles. It allows for removing damaged discs and inserting bone grafts and interbody cages to promote fusion. XLIF is typically used to treat degenerative disc disease or spinal instability.
5. ALIF (Anterior Lumbar Interbody Fusion): ALIF is an approach that accesses the spine through the patient's abdomen, specifically the front of the lower back. This approach provides direct access to the spine's anterior (front) region, allowing for the removal of damaged discs and insertion of bone grafts or interbody cages. ALIF is commonly used to treat degenerative disc disease, spinal instability, or certain deformities.
Understanding that each approach has advantages, considerations, and potential risks is essential. The choice of approach depends on various factors, including the patient's specific condition, surgeon preference, and anatomical characteristics of the underlying pathology. Surgeons evaluate each case individually and determine the most appropriate approach for the best possible outcome through discussion with the patient and his family. Surgical options and associated risks must be discussed openly, especially when pain interferes with the patient's perception of risk.
For example, the ALIF approach has about a 20% risk of causing retrograde ejaculation, a form of impotence. That might appear to be a minimal risk for the patient in extreme pain but a significant disappointment in outcome for the same patient who has had successful ALIF surgery and is no longer in pain.
For this reason and others, the plan for surgery is best made by discussing the surgical options with the patient and at least one significant other. Providing patients with a written description of associated risks can help them include family members in this decision.
Spinal surgery has evolved tremendously in the past forty years since the first implantation of pedicle screws. Accessing pathology from every angle, front to back, is now possible.