The influence of age on timing of single-event multilevel surgery: are adolescents with cerebral palsy comparable to a younger cohort?

Abstract

We are grateful to Švehlík et al.1 for providing some useful information on the long-term results of single-event multilevel surgery to improve gait in children with cerebral palsy, and for comparing two populations based on age. Although both groups improved substantially in their gait parameters postoperatively, the younger group saw some deterioration at their 10-year evaluation. However, the two groups are different in more than their age, as the authors point out. The younger patients had more soft tissue procedures and the older patients had more bony procedures. This would mean that the younger patients had more muscle activation and muscle length issues (i.e. contracture) than the older patients had when they were at that same age (or else those patients would have had soft tissue surgery when they were younger and been included in the younger group). Additionally, the older patients had more deformity and perhaps less muscle length and activation issues based on the procedures that they received, i.e. more bony procedures and fewer soft tissue lengthenings. This begs the question: is poor ambulation as a result of primarily bony deformity in an older child the same as poor ambulation as a result of muscular length and activation issues in a younger child? Probably not. The authors further note that the younger patients were all yet to experience their adolescent growth spurt and the older patients were either through, or in the midst of, their growth spurt at the time of their surgery and rehabilitation. The resulting limb growth that the younger group subsequently experienced is a major contributor to potential recurrence of soft tissue contracture in younger patients. Yet despite this, the number of follow-up operations was the same in the older group as it was in the younger group. Looking closer at the raw scores of the Gillette Gait Index, we find that the mean of the younger group decreased from 1657 to 613 at 10 years (a decrease of 63%), while the older group had a mean score that decreased from 1518 to 483 (a decrease of 68%) over that same time period. While statistically the younger children only reach a p value of 0.076 at 10 years, with the raw numbers as good as they are one cannot help but wonder if more patients would show that both groups maintained statistically significant improvement at 10 years post surgery. (The 7- to 8-y result had far smaller numbers so I would not draw any conclusions about that time period.) However, the article very nicely points out that children can see excellent results of well-done surgical intervention for ambulation at either the younger or older age. The types of surgery differ, but the follow-up surgeries are the same and improvement is maintained, although to a greater degree in those that will not require surgery until they are older. A child needs surgery when the gait has deteriorated sufficiently or failed to improve due to a soft tissue length or activation issue, or bony deformity. Some children require this early, some require it later. These are different children and one cannot simply postpone surgery until later and expect the same result when that child is older. These children represent different manifestations of cerebral palsy and this well conducted study shows us the difference between these groups of children.