Multiple Hemivertebrae: The Natural History and Treatment of 50 Patients

Multiple hemivertebrae (MHV) is defined as three or more hemivertebrae, and is relatively uncommon among patients with congenital scoliosis. This study aimed to compare the natural history of different kinds of MHV and describe the surgical outcome of MHV.

In this retrospective cohort study, a total of 50 patients diagnosed with MHV were enrolled from June 2007 to June 2018. The medical records and radiographs of these patients were reviewed to summarize the characteristics of MHV. Patients with MHV were divided into the unbalanced (UB) group, partially unbalanced (PUB) group, and completely balanced (CB) group. Medical records and radiographs of MHV patients were reviewed to collect HV position, natural history, coronal and sagittal parameters. A Mann-Whitney U test was used to compare the radiographical data, such as the cobb angle of main curve and secondary curve, and Fisher's exact test was used to compare the patients in different kinds of MHV with surgical indication or not.

The average number of hemivertebrae was 3.6 and the average main curve was 57.5°. Twenty-four of 50 patients had associated anomalies, including four patients with sacral agenesis, one with tetralogy of Fallot, two with congenital imperforate anus, and 17 with Klippel-Feil syndrome. In 22 patients who underwent MRI imaging, three patients had mild syringomyelia and three patients had diastematomyelia. The UB and PUB groups had a larger main curve and compensatory curve than the CB group. Of the 25 patients with follow-up before surgery, the curve progression rate was highest in the UB group (12.1°/year) but similar in the PUB group (4.2°/year) and CB group (3.6°/year). All patients in the UB and PUB group met the criteria for surgery. In contrast, only 10 of 23 patients in the CB group had surgical indications. Eighteen of the 37 patients with surgical indications chose to undergo surgery and the correction rate of the main curve was 51.4%.

Early surgical intervention should be considered for most patients with UB or PUB MHV. For patients with CB MHV, surgical treatment may not be urgently needed at the first visit. Posterior hemivertebrectomy could be used for the treatment of MHV with satisfying radiographic outcome.