Symptoms

Symptoms from back problems vary. They depend on a person's condition and which structures are affected. Some of the more common symptoms of low back problems are:

• Low back pain
• Pain spreading into the buttocks and thighs
• Pain radiating from the buttock to the foot
• Back stiffness and reduced range of motion
• Muscle weakness in the hip, thigh, leg, or foot
• Sensory changes (numbness, prickling, or tingling) in the leg, foot, or toes

A large herniated disc that pushes straight back into the spinal canal can put pressure on the nerves that go to the bowels and bladder. The pressure may cause symptoms of low back pain, pain running down the back of both legs, and numbness or tingling between in the legs. The pressure on the nerves can cause a loss of control in the bowels or bladder. If the pressure isn't relieved, it can lead to permanent paralysis of the bowels and bladder. This condition is called caude equina syndrome. Doctors recommend immediate surgery to remove pressure from the nerves.

Diagnosis

The diagnosis of low back problems begins with a thorough history of your condition. Your doctor will ask you questions to find out when you first started having problems, what makes your symptoms worse or better, and how the symptoms affect your daily activity.

Your doctor may do some simple tests to check the function of the nerves. These tests are used to measure the strength in your lower limbs, check your reflexes, and determine whether you have numbness in your legs or feet. Doctors commonly perform a leg-raising test. You lie on your back, and the doctor lifts your straightened leg upward to see if and where you feel pain. This test is mainly used to check whether there is pressure or irritation of the spinal nerves in the lowest part of the spine.

The information from your medical history and physical examination will help your doctor decide which tests to run. Imaging tests help your doctor see the anatomy of your spine. There are several kinds of imaging tests:

X-rays
Standard X-rays show problems with bones, such as infection, bone tumors, or fractures. They also show the amount of space in the neural foramen and between the discs. Unless the doctor suspects these problems, most patients don't require X-rays on their first doctor visit for low back pain.

MRI scans
Magnetic resonance imaging (MRI) scans use magnetic waves to create pictures of the cervical spine in slices. The MRI scan shows the neck bones and soft tissue structures such as the discs, joints, and nerves. MRI scans are painless and don't require needles or dye.

CAT scans
The CAT scan is a detailed X-ray that lets doctors see "slices" of bone tissue. It is used primarily when problems are suspected in the bones. A special dye is sometimes injected into the bloodstream before the CAT scan to help the doctor identify the spinal nerves.

Myelography
Myelography is a special kind of X-ray test. A special dye is injected into the space around the spinal canal--the subarachnoid space. The dye shows up on an X-ray helping the doctor see if there is a herniated disc, pressure on the spinal cord or spinal nerves, or a spinal tumor.

Discography
Dye is injected into one or more discs. The dye is seen on the X-ray and can give some information about the health of one or more discs.

Bone scan
A bone scan involves injecting "tracers" into your blood stream. The tracers then show up on special X-rays of your back. The tracers build up in areas of extra stress and bone activity, such as a fracture.

Electromyogram (EMG)
This is an electrical test of the nerves going to the lower limbs. EMGs are done to determine whether the nerves are being pinched.

Laboratory Tests
Not all causes of low back pain are from degenerative conditions. Doctors use blood tests to identify other conditions, such as arthritis or infection.