The spine is literally the "backbone" of the body. It starts at the neck and ends at the tailbone. The spine is structured in such a way to allow us to walk on two feet rather than most mammals that must walk on all 4 feet. Consequently, the back endures a great deal of stress, leaving it a common site of overuse pain as well as injury.
The spine is composed of 33 vertebrae which are grouped into regions defined by their location and function. From top to bottom, there are 7 cervical vertebrae (C1-C7), 12 thoracic vertebrae (T1-T12), 5 lumbar vertebrae (L1-L5), 5 fused sacral vertebrae (S1-S5), and 4 fused coccyx (tailbone) vertebrae. The cervical vertebrae in the neck allow for neck flexion/extension, rotation, and bending. The thoracic spine is connected to the rib cage and primarily functions to give the body support with very little motion. The lumbar spine ("aka- the lower back") allows the spine to flex (bend forward) and extend (bend backwards). The sacrum and coccyx are fused and function to connect the spine to the pelvis.
The spinal cord runs from the brainstem down to the lumbar spine and travels within the stacked vertebrae of the spine in a canal, or hole, in each vertebrae. The spinal cord is completely surrounded by the bone of each vertebrae which protects the spinal cord from injury. Nerves that control muscle function originate in the brain and travel first to the brainstem, then the spinal cord and then exit the spinal cord and travel to the muscle they control. Similarly, sensory nerves originate in the skin or muscle of the body and then travel first to the spinal cord, then up to the brainstem and finally to the brain for processing.
The spine is supported by muscles and very strong ligaments which permit movement of the spine (flexion/extension, rotation, and bending) but maintain stability. Finally, intervertebral discs sit between each of the stacked vertebrae in the spine and function as a cushion between the vertebrae during movement.
ACUTE SPINE INJURIES
These are fractures of the thoracic or lumbar spine that generally result from a high-energy mechanism including car crashes, falls from height, or contact sports that causes compression of the vertebrae. The energy of the injury causes the vertebrae to fracture, or burst, into multiple pieces. This results in the loss of height of the injured vertebrae and leads to potential instability of the spine causing a deformity and/or injury to the spinal cord. Evaluation of these injuries requires x-ray images of the spine including upright or standing x-rays to determine if the spine remains stable. A CT, or CAT scan, and/or an MRI is often required to obtain a better view of the injury. Generally, stable burst fractures are treated with braces and pain medication. However, burst fractures that are determined to be unstable are treated with surgical decompression of the spinal cord (a procedure called a laminectomy) and stabilization of the fracture with screws and rods.
Similar to burst fractures, these are fractures of the vertebrae that result from a compressive force. Generally, these injuries are lower energy than burst fractures, but occur from similar mechanisms. However, the injuries can also result from conditions that cause low bone density such as osteogenesis imperfecta. The compressive force from the injury causes the anterior, or front, part of the vertebrae to partially collapse resulting in a wedge-shaped vertebrae. These injuries are always stable and are treated with bracing for comfort and pain control. Once the initial pain is better, these children often benefit from a course of physical therapy to improve core strength.
Flexion/Distraction "Chance" Fractures:
These are fractures that result from a high-energy flexion of the body such as restraint from a seatbelt in a vehicle after a front-end collision. When the vertebrae are forcibly flexed forward the anterior vertebrae may compress, or wedge, like a compression fracture and the posterior part of the vertebrae or supporting ligaments pull apart in distraction. Treatment of these injuries depends upon whether the injury to the posterior spine is to the bony vertebrae or the supporting ligaments. Because bony injuries heal reliably well, these flexion/distraction injuries are treated non-surgically with a brace or cast. However, ligament injuries heal poorly and usually require operative treatment to stabilize the spine with screws and rods. In the picture to the right, this is essentially a ligamentous injury in an 8 yr old female that was injured in a car accident. This young girl, as is the case with many chance fractures, also had an abdominal injury requiring surgery before her spine was stabilized.
These devastating injuries are the result of very high-energy fractures that involve fracture of one or more vertebrae and injury to the supporting ligaments that support the spine resulting from a rotation force. The combination of these injuries makes the spine unstable and vertebrae can dislocate, or come out of normal alignment. Because the spinal cord runs within the stacked vertebrae, a dislocation causes in an injury to the spinal cord which can result in sensory deficits, muscle functioning deficits, or permanent paraplegia. These injuries often require immediate surgical treatment to decompress the spinal cord and stabilize the spine.
CHRONIC SPINE INJURIES
Back pain in the pediatric population can be due to a variety of causes ranging from pain associated with normal growth and activity to injuries requiring urgent treatment.
In young children, such as under 10, back pain is extremely uncommon unless there is a specific injury. If your child is experiencing back pain, then you should talk to your pediatrician to help determine if a visit to COA is necessary. The most common cause of "back pain" in young children is consitpation, and this is why a visit to the pediatrician is a good first place to start. Back pain is more worrisome, and especially in this young age group if your child is experiencing constant back pain (rather than intermittent pain that comes and goes), pain that is localized to one specific area (rather than more vague back pain), pain that requires pain medication, pain that limits activities, and especailly pain associated with fevers, chills, and weight loss. If any and/or all of these symptoms are occuring, your child needs medical attention at once.
In the adolescent age group, however, back pain is extremely common. Most of these children complain of pain with prolonged sitting and/or standing. They are typically not particularly active. Pain is typically across the middle of the lower back in the portion that is most arched in the lumbar spine. You may notice that your child slouches more often, and if you ask your child to "sit up straight" - she will say that it hurts. This pain rarely requires pain medication, and rarely limits your child from performing activities that he/she wants to do. Lack of core strengthening is the reason for this pain to occur. Usually, your child experiences this pain right after his growth spurt, and in general - muscles grow strong before they grow long. Thus, in order the back to stop hurting, your child needs to build up his back and core strength. If your child is unmotivated to improve his/her activity level, then a short course of physical therapy may be very helpful. Back bracing is rarely required.
Another cause of back pain, especially in your adolescent athlete, includes spondylolysis, which is a stress fracture due to overuse of the back. Please read below for further information.
There is a great deal of information your COA provider will ask in order to distinguish between the possible causes of back pain. Be prepated to answer questions regarding the onset, frequency, location(s), and severity of the pain as well as factors that make the pain better or worse. Other information including associated fevers, weakness or numbness, change in ability to walk, change in usual bowel and bladder habits is also helpful to narrow the scope of potential causes. A physical examination provides further important information and normally includes palpation of the spine and muscles of the back, assessment of possible spine curvature, forward/backward/side bending, and assessment of nerves and muscles strength. X-rays are typically ordered on the initial visit. When the cause of pain is still not clear, imaging tests may be obtained to assess the bones, muscles, ligaments, and/or discs in the spine, additional imaging and/or blood tests may be performed.
Back pain is an extremely broad topic and may or may not even be due to the back itself. Keep in mind, that while scoliosis is common, especially in the adolescent age group, smaller scoliosis curves rarely cause back pain. Most back pain in adolescents, just as with adults, will go away with time. As a parent, warning signs to look out for that require more immediate medical attention, as mentioned above, include:
- constant back pain
- back pain that is localized to one specific area
- back pain that requires increasing amounts of medication
- back pain that limits activities that your child wants to participate in
- back pain along with unexplained fevers, chills, or weight loss
Spondylolysis and Spondylolisthesis:
Spondylolysis is basically a defect in the vertebrae of the spine in a location of the bone known as the pars interarticularis. The term spondylolysis comes from the greek word "spondylos" which means spine, and "lysis" which means split. This pars region represents the connection between the front part of the back bone (vertebral body) which houses the spinal cord and nerves, to the back part of the back bone (posterior elements). It is not uncommon to find as many as six percent of ambulatory children with spondylolysis.
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