Lumbar discectomy is one of the most frequent operations Neurosurgery. Success in the surgical treatment of lumbar disc herniation is subject to individualized patient assessment and proper correlation between the data obtained from clinical history, neurological examination and diagnostic tests.
Most cases of sciatica resolve without surgery or specialized medical care, but 20% of cases about the evolution of these methods is unfavorable and should be considered surgical treatment. 90% of patients undergoing lumbar discectomy is relieved completely sciatic pain.
Causes of lumbar disc herniation
The origin of herniated lumbar disc is multiple. It is considered that the backbone structure is poorly adapted to bipedalism. That is why disc degeneration occurs that causes herniated disc, especially the joints between the fourth and fifth lumbar vertebrae and lumbosacral junction. Intense or less intense but successive lumbar overload injuries and posture are important in the development of pathology. Other factors may be genetic and nutritional acting in a further relaxation of the ligaments or less resistance of the fibrous ring.
Thus, the annulus fibrosus of the intervertebral disc may be progressively tearing, enabling first protrusion of the nucleus pulposus, after the appearance of hernia and eventually extruding. Often this process is accelerated by trauma or an intense overload.
The disc herniation is mechanical and inflammatory once: the mechanical compression of the nerve root leads to the release of inflammatory mediators that irritate the nerve root, accentuating the symptoms.
Symptoms of lumbar disc herniation, neurological examination
Lumbar disc herniations can be symptomatic or asymptomatic. The most common symptom is the picture of sciatica, consisting of low back pain spread to the back of the thigh reaching leg. Usually the pain is more intense in the leg than in the lumbar region intensifies with stretching movements nerve and actions that do increase the venous pressure and CSF, is relieved at rest and flexing the leg on the thigh and this on hip. Herniated discs on top of the lumbar cruralgia rise to a box of similar characteristics.
Lumbar disc herniation is the most common cause of sciatica, but not the only. Therefore, in a patient with sciatica should pay special attention to the appearance of warning signs: weight loss, severe trauma, immunodeficiency, fever or personal history of cancer, among others, which can warn a serious cause such as a fracture , spinal tumors or spondylodiscitis.
Less frequently, lumbar disc herniation, especially those that are central, bulky and young patient can present with cauda equina syndrome. This will be addressed urgently because in its most severe form, the function of all the roots of this part of the column may stop by a massive lumbar disc herniation. In these cases, the consequences can be: paraplegia, perineal anesthesia and lower limbs along with sphincter dysfunction and sexual impotence. However sciatic pain may or may not be present in varying degrees.
During the neurological examination should analyze the progress of heels and toes, patient attitude, mobility and lumbar curvature and antalgic scoliosis by asymmetric contracture of the spinal muscles. In addition, palpation can show contractures and pain play. Muscle strength of all muscles of the lower limb should be explored along with the tendon reflexes and plantar. Finally, we proceed to the maneuvers that trigger pain if root entrapment.
Still, neurological examination can reveal important changes or not, however, indicate different degrees of motor neuron or second superficial and deep sensitivity deficit.
Linking clinical anatomy
The effectiveness of the herniated disc operation is a function of getting an accurate diagnosis in which match the clinical manifestations, results of neurological examination and anatomical alterations in neuroimaging obtained.
Herniated discs can be classified into: central, lateral, lateral or foraminal and end extraforaminales, and in turn, tend to show a migration flow or cranial. In general, a herniated disc compresses the root that starts at a lower segment. As an exception are the lateral end hernias that compress the root that arises at the same level.
Surgical treatment for hernia
90% of the ischial improve with conservative treatment during the first weeks. Therefore usually wait at least four to six weeks before indicating surgery, as long as an engine or cauda equina syndrome deficit is not present.
In short, there are three situations where lumbar discectomy surgery is necessary:
- Cauda equina syndrome or cauda equina
- progressive neurological deficit
- significant pain despite conservative treatment prolonged for two months
Isolated cases of low back pain are not a decisive factor for discectomy. The best indicator is suffering a monorradicular sciatica and predicts a greater response to the root decompression. Other indicators are motor deficit levels and sensitive.
Moreover, they should take into account patient preferences about recovery time. The long-term microdiskectomy are similar to those of conservative treatment when there are no neurological deficits, although the recovery is significantly faster with surgical treatment.
Surgical procedures for lumbar disc herniation
A priori, any surgery must undergo four general principles:
- be simple
- be effective
- Respect anatomy
- Be fast.
The reference technique is microdiskectomy, made with the help of a surgical microscope consisting exposure below the periosteum membrane tissue attached to the exterior of the bones, the space between corresponding blades. Subsequently, a hemiflavectomía is done to remove the ligamentum flavum and sometimes, the removal of a minimal portion of the sheet or the articular process. Once it detected the root, the fragment that the compressed and holds the annulotomy and removal of the nucleus pulposus is removed.
Another technique which in the last decade is the tubular discectomy, consisting of introducing a Kirschner wire parasagittal situation (perpendicular to the ground and at right angles) at the interlaminar space corresponding. Through this needle a succession of progressively larger diameter dilators are inserted until finally the transmuscular separator is introduced for use as working channel. The vision of the surgeon can be improved by a surgical microscope or endoscope.
The importance of posture in the herniated disc
The goal of good posture is to decrease the pressure in the epidural venous plexus, helping respiratory mechanics, open spaces between sheets, allowing surgery and reduce the risk of complications. The two options are supported prone position, the patient is resting on his back with stretched and placed along the body arms, legs straight and placed parallel and aligned with the spine and back. Then there is the knee-chest, in which the patient is placed face down and the trunk resting on the knees and chest. The patient must first rely on his knees on a surface and flex the waist so that the hip is on top and the head on the floor. These two positions are recommended, since they prevent abdominal compression transferring weight to another part of the body other than the lumbar part. Many of the most serious complications of lumbar discectomy as blindness or neuropraxias is the cause of an incorrect posture of the patient during surgery.
Results of treatment of sciatica for lumbar disc herniation
The main goal of surgical treatment is removal of the intervertebral disc, but release decompress the nerve root and thus relieve pain and facilitate recovery of neurological deficits, in case there. Secondarily the nucleus pulposus is partially removed to avoid relapse or recurrence of hernia.
Edited by Roser Berner Ubasos.