Hernia Nucleus Pulposus (HNP)
Introduction and Facts
A hernia is a protrusion or protrusion of an organ or tissue through an abnormal opening. The nucleus pulposus is a semifluid mass made of white elastic fibers that form the intervertebral disc's center (Company, 2000). Hernia Nucleus Pulposus (HNP) is a disorder that involves rupture of the annulus fibrosus so that the nucleus pulposis protrudes (bulging) and presses towards the spinal canal (Autio, 2006).
The prevalence of HNP ranges from 1 – 2% of the population. The most common age is the age of 30-50 years. In studies, HNP is most often found at the L4-L5 level; body fulcrum at L4-L5-S1. The study of Dammers and Koehler in 1431 patients with lumbar disc herniation showed that L3-L4 HNP patients were significantly older than L4-L5 HNP patients (Pinzon, 2012).
Pathophysiology
a. Degenerative Process
The intervertebral discs are composed of fibrocartilage tissue that acts as a shock absorber, disperses forces on the vertebral column, and allows movement between the vertebrae. The disc's water content decreases with age (from 90% in infants to 70% in the elderly). In addition, the fibers become coarse and undergo hyalinization, which helps to change the direction of herniation of the nucleus pulposus through the annulus and compresses the spinal nerve roots. In general, hernias are most likely to occur in parts of the vertebral column where there is a more mobile to a less mobile segment (the lumbosacral and cervicotolar junction).
b. Traumatic Process
The onset of disc degeneration affects the mechanics of the intervertebral joints, which can lead to further degeneration. In addition to degeneration, repetitive movements, such as flexion, extension, lateral flexion, rotation, and lifting weights, can put abnormal stress on the nucleus. If this pressure is large enough to injure the annulus, this nucleus pulposus leads to herniation. Acute trauma can also cause herniation, such as lifting objects the wrong way and falling.
Hernia Nucleus Pulposus is divided into 4 grades based on the state of herniation, where extrusion and sequestration are true hernias, namely: (Grade I) Intervertebral disc protrusion: the nucleus appears to protrude in one direction without damage to the annulus fibrosus., (Grade II) Intervertebral disc prolapse : nucleus displaced, but still within the ring of the annulus fibrosus., (Grade III) Intervertebral disc extrusion: nucleus exits from the annulus fibrosus and is below the ligament, posterior longitudinal., (Grade IV) Intervertebral disc sequestration: nucleus has penetrated the posterior longitudinal ligament.
The herniated nucleus pulposus can compress nerves in the spinal cord if they penetrate the disc wall (annulus fibrosus); this can cause pain, numbness, cramping, or weakness. Pain from this herniation can be mechanical pain, originating from the disc and ligaments; inflammation, pain originating from the extruded nucleus pulposus through the annulus and in contact with the blood supply; and neurogenic pain, which originates from compression of the nerves.
Clinical Symptoms and Complications
The primary clinical manifestation is pain in the lower back accompanied by muscles around the lesion and tenderness. HNP is divided into central and lateral HNP. Central HNP will cause flaccid paraparesis, paresthesias, and urinary retention. At the same time, lateral HNP manifests in pain and tenderness in the lower back, in the middle of the buttocks and calves area, behind the heels, and soles of the feet. The power of extension of the fifth toe is reduced, and the Achilles reflex is negative.
In L5-S1 lateral HNP, pain and tenderness are found in the lower back, lateral buttocks, lateral lower limbs, and dorsum pedis. Weaknesses m. gastrocnemius (plantar flexion of the ankle), m. extensor hallucis longus (extension of the big toe). Achilles reflex disorders, sensory deficits in the lateral malleolus and the lateral part of the pedis (Setyanegara, et al, 2014).
Diagnosis
Neurological examination to ensure that the pain that arises is included in a nervous disorder consists of the sensory, motor, reflex examination.
a. Sensory examination, in this sensory examination, whether there is a sensory disturbance, by knowing which dermatome is affected, it is possible to know which root is affected.
b. Motor examination, whether there are signs of paresis, muscle atrophy.
c. Reflex examination, if there is a decrease or disappearance of tendon reflexes, for example, APR decreases or disappears, it means that the S1 segment is disturbed.
The tests that can be done to diagnose hernia nucleus pulposus (HNP) are:
a. Range of Movement (ROM) check
This examination can be carried out actively by the patient himself or passively by the examiner. This ROM examination estimates the degree of pain, function laesa, or check the presence or absence of the spread of pain.
b. Straight Leg Raise (SLR) test.
Test to determine the presence of sciatic nerve entrapment. The patient lies supine, and the examiner flexes the pelvis passively, with the leg's knee maximally extended. This test is positive if there is a pain when lifting the leg straight, indicating compression of the lumbar nerve roots.
c. Crossed Lasergue.
The method is the same as the lasegue experiment, but here automatically arises pain in the leg that is not removed. This indicates that the contralateral root is also involved.
d. Kerning Sign
In this examination, the lying patient flexed his thigh at the stage joint to make an angle of 90 degrees. In addition, the lower leg is extended at the knee joint. Usually, we can do this extension to an angle of 135 degrees between the lower leg and upper leg; if there is resistance and pain before reaching this angle, it is a positive kerning sign.
e. Ankle Jerk Reflex
Tap on the Achilles tendon. If there is no dorsiflexion of the foot, this indicates a nerve entrapment at the level of the L5-S1 vertebral column.
f. Knee-Jerk Reflex
The knee-tendon is tapped. If there is no extension at the knee, this indicates a nerve entrapment at the level of the L2-L3-L4 vertebral column.
Supporting Diagnosis
a. X-Ray
The X-Ray cannot accurately depict soft tissue structures. The nucleus pulposus cannot be captured on X-Ray and cannot confirm disc herniation or nerve root entrapment. However, X-Ray can show disc abnormalities with a narrowing of the gap or a change in the alignment of the vertebrae.
b. myelogram
On myelogram, radio-opaque contrast injection is performed in the spinal column. Contrast enters the spinal column so that the X-ray can show blockage or obstruction of the spinal canal.
c. MRI is the gold standard for diagnosing HNP because it can see the vertebral column's structure and identify the location of the herniation.
d. Electromyography
Medication and Treatment
Non-Pharmacological Therapy, namely:
a. Warm/cold compress
This warm/cold compress is an easy modality to do. To reduce muscle spasms and inflammation. Some patients experience pain relief with warm compresses, while others experience cold compresses.
b. Iontophoresis
It is a method of administering steroids through the skin. These steroids exert an anti-inflammatory effect on the area causing the pain. This modality is especially effective in reducing attacks of acute pain.
c. TENS Unit (Transcutaneous Electrical Nerve Stimulator)
A transcutaneous electrical nerve stimulator (TENS) unit uses electrical stimulation to reduce the sensation of low back pain by interfering with pain impulses sent to the brain
d. Ultrasound is heating in the deep layers by using sound waves on the skin that penetrate the soft tissue underneath. Ultrasound is especially useful in relieving attacks of acute pain and can promote tissue healing.
Exercise and lifestyle modification
Excess weight must be reduced because it will increase the pressure on the lower back. Diet and exercise programs are essential to reduce LPB in patients who are overweight. It is recommended to start light, stress-free exercise as soon as possible. Endurance exercise aerobic exercise that puts minimal stress on the back, such as walking, cycling, or swimming, begins in the second week after LBP onset. Conditional activity that aims to strengthen the back muscles is started after two weeks because it may aggravate the patient's complaints if it is started early. Exercises to strengthen back muscles using tools are not more effective than exercises without tools.
Pharmacological Therapy
a. Analgesics and NSAIDs (Non-Steroid Anti-Inflammation Drugs) are given to reduce pain and inflammation to speed up healing. Examples of analgesics: paracetamol, Aspirin Tramadol. NSAIDs : Ibuprofen, Diclofenac sodium, Ethodolac, Selekoksib.
b. Muscle relaxants (muscle relaxants) are helpful when the cause of LBP is muscle spasm. The therapeutic effect is not as strong as NSAIDs, often in combination with NSAIDs. About 30% give side effects of drowsiness.
Examples of Tinazidin, Esperidone, and Carisoprodol.
c. Opioids. This drug has proven to be no more effective than regular analgesics, which are much safer. Long-term use can lead to tolerance and drug dependence.
d. Oral Corticosteroids, The use of oral corticosteroids is controversial. Used in cases of severe HNP and reduces tissue inflammation.
e. Adjuvant analgesics, primarily used in chronic HNP because there is an assumption that the pain mechanism in HNP is neuropathic. Examples: amitriptyline, carbamazepine, gabapentin.
f. Injection at the trigger point
This treatment method is by injecting a mixture of local anesthetics and corticosteroids into the soft tissue/muscles at trigger points around the spine. This method is still controversial. Drugs used include lidocaine, lignocaine, dexamethasone, methylprednisolone, and triamcinolone.
Operative Therapy
Performed on the patient is done if:
a. The patient has HNP grade 3 or 4.
b. There is no improvement, pain persists, or functional impairment after 6 to 12 weeks of conservative therapy.
c. The frequent recurrence of symptoms experienced by the patient causes functional limitations to the patient, although conservative therapy given each recurrence can reduce symptoms and improve patient function.
d. The therapy given is less focused and runs for a long time.
Surgical treatment options that can be given are:
a. Distectomy Partial removal of the intervertebral disc.
b. Percutaneous discectomy. Partial removal of the intervertebral disc using needle aspiration.
c. Laminotomy/laminectomy/foraminotomy/facetectomy
They are performing neuronal decompression by removing some parts of the vertebrae either partially or totally.
d. Spinal fusion and sacroiliac joint fusion: The use of grafts on the vertebrae to form a rigid connection between the vertebrae for stability
Reference:
1. HNP [Internet]. Available from: https://sinta.unud.ac.id/uploads/kode_dir/464eb57bfb86f13cb48f856a325ff96a.pdf
2. Hernia Nucleus Pulposus [Internet]. Available from: https://med.unhas.ac.id/kedokteran/wp-content/uploads/2016/09/Bahan-Ajar-4_Hernia-Nucleus- Pulposus.pdf
