Acute Low Back Pain- Lumbar Disc Herniation

Acute Low Back Pain Lumbar Disc Herniation

Low back pain is a common condition. 90% of patients with low back pain will improve without surgery. Usually they get better with spontaneous resolution of the symptoms within 12 weeks. We usually advise the patient for early return to activity and function as the symptoms and the pain permits. The risk factors for development of low back pain are numerous, some include: vibration exposure, poor physical fitness, smoking and obesity, anxiety and depression, job dissatisfaction, or repetitive bending or “stooping” on the job. The worst pressure on the disc occurs with prolonged sitting and bending over.  In summary, if the patient has no red flags and has a normal neurological exam, there is no reason to get early radiological studies. Getting early x-rays and early MRIs leads to a better patient satisfaction but does not give a better patient outcome. If there is no specific pain pattern, then there is no need for further workup. MRIs are good studies, but they give false positives. There is degeneration or a bulge of a disc in 35% of all asymptomatic subjects between 25-39 years of age. In patients 60 years old or older, the majority of the patients will have changes in the MRI. MRI abnormalities are common and must be correlated with the age and the clinical signs and symptoms of the patient. An MRI is good for diagnosing the lumbar disc herniation, which is sometimes called a ruptured disc, a slipped disc, or a herniated disc. The most common location of a disc herniation is a posterolateral herniation involving one nerve root. A foramninal L4-L5 herniation occurs in about 8%-10% of the cases. It involves the exiting nerve. A central herniation involves multiple nerve roots. It predominantly causes low back pain more than leg pain. It may cause bladder and bowel symptoms. This type of disc herniation causes Cauda Equina Syndrome which needs urgent diagnosis and surgical treatment. Clinical evaluation for a herniated disc examines sensory and motor reflexes. The Straight Leg Raising Test is the most important finding. It can be done in either the sitting or supine position. The test is positive as indicated by pain in the leg when the patient’s leg is raised to flex the hip with the knee extended. A positive straight leg test means a tension sign, something is putting tension or stress on the sciatic nerve. When the test is positive, it indicates possible disc herniation. Treatment is typically non-operative. First, reassure the patient. Let the patient take some rest (no more than a few days), give the patient anti-inflammatory medication, and instruct them to attend physical therapy. Indications for surgery include progressive neurological deficits, Cauda Equina Syndrome, the patient is not getting better with time and treatment or if the symptoms are not getting better with conservative treatment, or the patient has a positive tension sign with persistent sever pain. Patients with sciatica and positive tension signs or patients with positive neurological findings on clinical exam with positive MRI findings make ideal surgical candidates. Surgery results in relief of leg pain in the majority of patients. Back pain may persist in some patients.

Surgery results in neurological improvement, 50 % motor and sensory and 25% reflexes. In patients with discogenic back pain, they may need fusion which is a major procedure.This is the position that produces the highest pressure on the disc. If a patient has back pain but no radiation, by the patient’s history or physical examination and there are no red flags, then there is no reason to get x-rays or MRI early in the treatment of the patient. Red flags include a history of trauma, a tumor, infection, or Cauda Equina Syndrome symptoms. To rule out a history of trauma you should rule out fractures with x-rays, MRI, or CT scans. Tumors are a risk if the patient is older than 50 years old, if the patient had weight loss, or if the patient has pain at rest or at night. An infection may be present if the patient has fever and chills, if the patient has a history of diabetes, or if the patient has a history of IV drug abuse. Cauda Equina Symptoms may be present if the patient has back pain more than leg pain or if the patient also has bladder and bowel symptoms. Cauda Equina Syndrome needs to be diagnosed and surgically treated early. An MRI needs to be ordered urgently in the course of treatment. The MRI should be ordered STAT. There may need to be a wet read; a wet read is an early preliminary read of the radiographs. A wet read needs to be communicated with the physician and can be done while the patient is still on the table of the MRI.