According to a study from Peking University, China, the majority of children and adolescents that present with herniated discs in the lumbar spine also have some kind of malformation of the spinal vertabrae.
The study, which was published in Neurosurgery, can help to explain how children and adolescents can develop lumbar disc herniation (LDH) without the ’wear and tear’ which causes LDH in adults. The results of the study, by Zhongjun Liu, Peking University Hospital, Beijing, China, and colleagues, suggest that spinal fusion may not be necessary in young patients with low back pain from herniated discs. Surgery on the disc itself may be sufficient.
To look for structural malformations that might predispose to herniated disks in children and teens, the researchers analysed the X-rays of 63 patients under age 20 with LDH. The patients were 37 males and 26 females, average age 17 years. All required surgery for severe, disabling back pain that didn’t respond to other treatments.
In nearly all patients, X-rays showed at least one type of malformation involving the lumbar spine and sacrum. “Malformations were completely absent in only three cases,” according to Liu and colleagues.
Some patients had an abnormally “high” pelvis, with transverse processes of the lowest lumbar vertebra (L5). These patients were most likely to have herniation of the disc between the two lowest lumbar vertebrae (L4/L5). In contrast, patients with an abnormally “low” pelvis were more likely to have herniation of the disk between the lumbar spine and sacrum (L5/S1).
Other patients had “transitional vertebrae” between the lumbar spine and sacrum. This malformation also affected the rate of L4/L5 versus L5/S1 herniation, depending on the location of the transitional vertebra.
The researchers also looked at how patients responded to surgery for LDH. In 36 patients, surgery consisted only of discectomy. Twenty-seven patients also underwent arthrodesis of the involved vertebrae.
In all patients, surgery led to significant reduction in back pain and disability. Outcomes were similar with discectomy alone versus discectomy plus arthrodesis.
Based on their findings, Liu and coauthors write, “Congenital lumbosacral malformations are significantly associated with LDH in children and adolescents.” The malformations may be associated with abnormalities of the iliolumbar ligaments, leading to impaired stability of the lower spine.
The experience also suggests that paediatric patients with LDH get significant pain relief from surgery on the involved disc only; performing spinal fusion of the malformed vertebrae does not seem to add additional improvement. Liu and colleagues note some important limitations of their study—especially the fact that it did not assess the rate of spinal malformations in a control group of young patients without herniated discs.