Pediatric Low Back Pain

By Peter Fysh, DC

Case Report

A mother brings her 11-year-old daughter to the chiropractor because of pain in the lower back, which her daughter has been experiencing for the past several weeks.

The daughter has been a competing gymnast for the past three to four years. She complains of back pain after each training session. Her program requires that she train for four hours each day, five days a week. After each session, the back pain is significantly worse, but it improves with rest, usually after lying on the bed for 45 minutes to an hour. On questioning the patient further, the pain is described as a sharp aching pain, precisely located to a small area in the low back just left of center at the belt line.

Physical examination reveals no significant findings other than the lower back pain located over the left lumbosacral junction. The patient can bend over to touch her toes without pain, but when lying face down, arching her back upwards and extending the spine reproduces the pain in the exact area of complaint.

Discussion

The incidence of low back pain in children is significantly lower than that which occurs in adults. The most common adult low back pain is due to "deconditioning," with lack of exercise and general physical fitness being the main cause of the deconditioning process. In children, however, this is not the case. Children generally do not suffer from such problems. Low back pain in children is more commonly caused by a spondylolysis defect in the pars interarticularis, or facet tropism at the lower lumbar spinal motion segments (L4-5 and L5-S1). Another possible cause of low back pain in the pediatric age group could be infection of an intervertebral disc, known as diskitis.

Spondylolysis is present in five percent of the adult population and in children the incidence reaches this level at about seven years of age.¹ In gymnasts, the incidence of spondylolysis has been found to range from 11 percent to 15 percent, most frequently associated with a stress fracture in the pars interarticularis of a lower lumbar vertebra. Slippage of a spondylolysis into a spondylolisthesis occurs most often during an adolescent growth spurt, between the ages of 9-15 years. Further slippage of the affected vertebra rarely occurs after the age of 18 years.

Facet tropism, where the planes of the facet articulations are asymmetrically aligned, is a heredity condition which has common occurrence in the population. It is a frequent cause of low back pain in children, especially those engaged in sports which involve hyperextension of the lower spinal segments, e.g., gymnastics, dancing, volleyball, and basketball.

The possible causes of the back pain in our 11-year-old patient should include all of the above and an appropriate diagnostic protocol should be used to evaluate the exact site and nature of the problem. The fact that the patient can bend forward and touch the floor without pain should rule out ligament sprains and muscle strains. Low back strains and sprains normally improve with hyperextension, and since this patient's problem is exacerbated by this move, we have further reason to rule out sprain/strain injury. Since gymnasts are extremely flexible, care should be taken in interpreting range of motion tests. A straight leg raise which ends at the patient's nose is not abnormal in gymnasts.

Diagnosis

To confirm the diagnosis, AP, lateral, and oblique radiographs of the lumbar spine should be obtained. If spondylolysis is present, evidence of a separation of the pars interarticularis should be visible on the oblique view. If no separation is visualized, then the lower lumbar facet joints should be examined for evidence of asymmetry. Asymmetrical alignment of the facet joints can predispose to instability of the associated spinal motion segment, especially in the lower lumbar region, where the presence of the sacral base angle causes additional stress to be placed on any truly sagittal facet joint. Disc infection can be ruled out by radionuclide bone scan, which will be positive very early in the course of the infection. If none of these possibilities are evident, then the patient may be treated specifically for facet joint and sacroiliac fixations, taking appropriate care not to exacerbate any existing hypermobile joint structures.

Management

Treatment should be appropriate for the confirmed diagnosis. If spondylolysis is encountered, then a lumbosacral brace may be prescribed to be worn for 22 hours each day until the patient is asymptomatic, which may be as early as three weeks.² Concurrently, hyperextension activities should be restricted and a rehabilitation program commenced. Frequently, gymnasts will have a hyperlordosis of the lumbar spine associated with weak abdominals, tight lumbosacral fascia, weak hamstrings and tight rectus femoris muscles. This pattern of muscle imbalance is characteristic of a poor training regimen coupled with weak abdominals from constant stretching in back walkover maneuvers. The rehabilitation program should include abdominal and hamstring strengthening exercises, posterior pelvic tilts in both the standing and supine position, and stretching routines for the tight quadriceps.

Summary

Early and appropriate management of spondylolysis may produce a complete healing of the stress fracture. In dealing with facet tropism, it must be remembered that the symptoms are likely due to a hypermobility of a unilateral facet joint, secondary to a congenital anomaly. The persistence of this anatomical variant will predispose to reoccurrence of the problem, especially if hyperextension activities are not eliminated.

Our 11 year old patient actually had an anomalous facet joint at the left L5-S1 level, due to facet tropism, and is doing well after two months on the rehabilitation exercise program. Her symptoms have subsided; she is back to gymnastics with instructions to limit her hyperextension activities, and to work on correcting any faculty movements in her routine.

References 

1. Wiltse LL: Treatment of spondylolisthesis and spondylolysis in children. Clin. Orthop., 117:92-100, 1976.
   
   
2. Michelli LJ: Back injuries in gymnastics. Clin Sports Med., 4:85-93, 1985.