Treatment principles and surgical indications
Pathologies of the lumbar intervertebral discs, commonly known as a slipped disc, are a frequent cause of low back pain and radicular leg pain. The etiology is multifactorial, rooted in trauma, tissue degenerative changes, or a combination of these factors.
The clinical algorithm is based on a thorough history taking and physical examination, followed by diagnosis verification using magnetic resonance imaging (MRI).
In most situations, therapy is conservative and highly effective. Patients are prescribed nonsteroidal anti-inflammatory drugs (NSAIDs) combined with physical therapy and physical therapy. However, if medical treatment fails, surgical treatment is applied. Surgical surgical decompression of neural structures is strictly indicated in the presence of two key manifestations:
- Unremittingly progressive neurological deficit.
- Disabling pain syndrome (disabling pain) that deprives the patient of working capacity.
Anatomy and histology of the disc
A thorough understanding of the target area's anatomy is required to fully grasp the essence of the surgical intervention. There are a total of 23 intervertebral discs in the human body, located in segments from the second cervical vertebra (C2) to the first sacral vertebra (S1).
Normally, the tissue is located entirely within the disc space (disc space). Its superior and inferior boundaries are formed by the vertebral body end plates (vertebral body end plates), and its periphery by the outer margins of the vertebral bodies themselves. In the sagittal and axial projections, the posterior surface of a healthy disc should lie on a single continuous line with the posterior surface of the bony vertebral body.
Each disc functions to provide spinal mobility (rotation, flexion) and shock absorption for axial forces. The disc consists of two layers containing water, proteoglycans, and type I collagen in varying proportions:
- Annulus fibrosus (Annulus fibrosus): the dense outer layer. A high concentration of collagen relative to water and proteoglycans gives it immense tensile strength.
- Nucleus pulposus (Nucleus pulposus): the gel-like inner part. Due to the predominance of water and proteoglycans, the nucleus effectively resisting compression under axial loads.
Classification of displacements
According to the standards of leading global radiological societies (NASS, ASSR, ASNR), the protrusion of disc structures beyond the anatomical space is strictly classified.
- Bulge (Bulge): diffuse and symmetric expansion of the annulus fibrosus evenly along the entire circumference.
- Herniation (Herniation): focal displacement encompassing strictly less than 25% of the disc circumference.
In turn, disc herniation are divided into two types based on geometric MRI criteria:
- Protrusion (Protrusion): on axial view, the width of the base of the bulge is always greater than the distance the material has shifted.
- Extrusion (Extrusion): the displacement distance exceeds the width of the base, meaning the herniated tissue is narrower than its base.
Among specific, surgically significant forms is a sequestered disc herniation (Sequestered disc herniation), in which the extruded tissue completely loses anatomical continuity with the parent disc. Intravertebral herniation (Intravertebral herniation) also occurs, where the nucleus pulposus herniates directly into the cancellous bone of the vertebra through a defect in the endplate.
Briefly: answers to topical questions
What specific types of surgical interventions are used to remove an intervertebral disc herniation?
Open, microsurgical, and minimally invasive procedures are used to remove intervertebral disc herniations.
- Hemilaminectomy and discectomy — traditional open approach with removal of a portion of the vertebral lamina and the herniated disc.
- Microdiscectomy — a similar procedure with a smaller incision, using an operating microscope and specialized retractors.
- Percutaneous endoscopic disc decompression — a minimally invasive procedure performed using instrumental or laser methods.
What surgical approaches are used in the surgical treatment of lumbar hernias?
Anterior and posterior surgical approaches are used in the surgical treatment of lumbar disc herniations.
- Anterior approach — used in some cases at the lumbar level.
- Posterior approach — is one of the utilized surgical approaches.
Hernia removal using video-endoscopic technologies from various approaches has comparable clinical and radiological results to standard removal.
What specific neurological symptoms occur with L5 spinal nerve root compression?
Compression of the L5 spinal nerve root results in radiculopathy characterized by sensory and pain disturbances within its innervation zone.
- Pain syndrome — pain wraps around the leg, extending to the lateral aspect of the lower leg and onto the dorsum of the foot.
- Paresthesias — extend distally along the lateral surface of the lower leg and the dorsum of the foot.
- Tactile hypesthesia — decreased tactile sensitivity in the specified area.
- Hypoalgesia — decreased pain sensitivity on the lateral surface of the lower leg and the dorsum of the foot.
Muscle weakness in the affected limb is also possible.
What intraoperative and postoperative complications are possible in the surgical treatment of disc herniation?
A number of specific intraoperative and postoperative complications can occur during surgical treatment of a disc herniation.
- Dural tear — can lead to postoperative cerebrospinal fluid leak.
- Neurological deficits — onset or worsening of motor and sensory deficits, pelvic organ dysfunction.
- Epidural hematoma — accumulation of blood in the epidural space.
- Surgical site infections — purulent-inflammatory processes in the surgical area.
- Implant-related complications — screw malposition, implant migration, fractures of metalwork elements and vertebral components.
- Postoperative Stenosis (Postoperative Stenosis) — foraminal narrowing due to decreased intervertebral space height following discectomy.
For quick MRI reading: in Protrusion, the base Exceeds the length, while in Extrusion, the length is Extremely greater than its base.
Class and exam questions
At which lumbar levels do hernias form most frequently?
Due to maximum axial loads, the intervertebral segments L4-L5 and L5-S1 are the typical localization for herniations.
What is the main difference between disc bulging and a herniation on MRI?
A bulge represents a symmetric and uniform tissue protrusion along the entire circumference. A herniation, however, is a strictly focal process occupying less than a quarter of the disc circumference.
What is a sequestered hernia?
This is a pathological condition in which the extruded disc fragment completely detaches from the parent disc, losing its anatomical connection.
What else to study on this topic
- Assessment and symptomatology of progressive neurological deficit in disc herniations.
- Biomechanics of the nucleus pulposus under excessive axial loads.
- MRI reading technique: axial and sagittal projections of the disc space.
- Anatomical defects of the endplates and the development of intravertebral hernias.
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