Understanding Lumbar Spine Trauma

Article written by Eeric Truumees, MD

Sadly, trauma to the low back (lumbar spine) is common. People find hundreds of ways to injure their low back: car accidents, sports injuries, workplace injuries, falls, and violence. Doctors divide lumbar spine injuries into two broad categories, low and high energy. An example of a low energy injury would be a fender bender in which one car is stopped and the other is going 5 miles per hour. This type of collision or a fall while in the shower can cause low back pain, but the types of injuries seen are very different from a high speed collision in which the passenger is ejected from the car. Knowing exactly what happened to you helps the doctor figure out exactly what type of back injury you have. Another important element lies in any risk factors you may have for back injuries. For example, patients with soft bone (osteoporosis) may break their spine with less energy than someone with strong, healthy bone.

Low back spine injuries are also divided by the part of the back that was damaged. Injuries can affect the bone (fractures), the disks (herniations), ligaments (sprain), or muscles (strain). Each of these tissues has different needs while healing and some take longer than others. Doctors will list the level or levels affected. L1 (Lumbar 1) is at the top of the low back, L5 is at the bottom. Below the lumbar vertebrae is the sacrum.

Next, spine surgeons grade the severity of injury. For example, fractures range from simple compression fractures, where the bone collapses upon itself like a Styrofoam cup getting squashed together, to burst fractures, when pieces of bone explode out into the tissues around the spine, including the nerves and spinal cord. The worst of these injuries are called fracture-dislocations. Here, the bone breaks but, because the ligaments are torn as well, the bones slide away from each other. This situation is very unstable and almost always needs surgery.

Often, how a back injury is treated will depend on whether the nerves or spinal cord are involved. Luckily, many low back injuries will not involve the spinal cord, which ends in the upper part of the low back (at the L1-2 disk). The lowest part of the cord is called the conus medullaris. If this part of the cord is injured, patients will have trouble with bowel, bladder, and sexual function.

Below the conus medullaris are individual nerves (the cauda equina). While nerve injuries are not usually as devastating as spinal cord problems, pressure on many nerves at once (called cauda equina syndrome) is an emergency because long term leg weakness and bowel and bladder problems often results. Injury to a single nerve (sciatica or radiculopathy) may be intensely painful, but is less likely to cause major, permanent problems. If the part of the leg that that nerve goes to is weak, surgery will often be recommended, as it is with patients with spinal cord or cauda equina problems.

Strains, while painful, do not usually affect the nerves or the stability of the spine. Sometimes braces are used. Usually patients will require physical therapy to regain back strength. Most of these problems get better over 6 to 12 weeks.

Sprains or injuries to the spine ligaments may be relatively simple injuries and treated like strains. Sometimes, however, one of the major stabilizing ligaments of the spine is injured and surgery is needed to prevent the spine from slipping. That problem is more common in the neck than the low back.

In the low back, most serious injuries involve fracture of the spine or a disc herniation. Many of these can be treated non-operatively. More instability, collapse or nerve involvement leads to surgery. The goals of surgery are typically to take the pressure off the cord and nerves, improve the alignment of the spine, and to provide stability. Many injuries don’t include all three problems. But, for major alignment and stability problems, surgical correction often requires screws and rods to hold the spine back together. Bone grafts are used to allow the patients bones to heal together (fusion).

In some cases, the need for surgery is clear from the start (for example, the patient is getting weaker and weaker). Other times, an attempt is made to get the injury, a fracture for example, to heal in a brace. If the spine heals as expected, the brace is removed and therapy is started. If the spine fails to heal or the spine continues to collapse, surgery will be recommended. This can occur weeks or months after the initial injury.

In trauma, surgery may need to be performed from the front of the spine. Here an incision is made along the side of the abdomen. Sometimes one of the lower ribs is removed. This allows the surgeon direct access to the big vertebral body (the main bone of the spine). Broken fragments of bone can be removed and a strut of bone or a metal cage can be put it to keep the spine aligned. In other cases, an incision is made in the middle of the back and screws and rods are used to hold the spine. Smaller pieces of bone graft are placed along the spine to encourage it to heal together. For particularly severe or unstable injuries, surgery from both the front and the back of the spine is performed. The details about the various types of surgeries performed are available on this website.