TO THE EDITOR: We read with great interest the article by Mansur et al.1 (Mansur A, Morgan B, Lavigne A, et al. Comparison of intrathecal baclofen pump insertion and selective dorsal rhizotomy for nonambulatory children with predominantly spastic cerebral palsy. J Neurosurg Pediatr. 2022;30[2]:217-223) regarding the short- and medium-term outcomes, care needs, and complications between intrathecal baclofen (ITB) pump and selective dorsal rhizotomy (SDR) in nonambulatory patients with spastic quadriplegic and diplegic cerebral palsy (CP) (Gross Motor Function Classification System [GMFCS] levels IV and V). The authors are to be congratulated on their work, and we agree on the importance of the topic. We do, however, have several comments.
First, compared with a reported 30-year time frame of surgical practice, the work focuses on short- and medium-term outcomes, with an average follow-up of 18 months. It is well known that some complications develop in the long term (e.g., surgical scoliosis and hip dislocation). Moreover, the highest risk of skeletal deformity occurs during adolescent growth and is often associated with combined effects of contractures, altered neural drive, reduced mechanical loading, and suboptimal nutrition.2,3 In this context, the difference in mean age at surgery may represent a greater bias. Accordingly, it would be interesting to have more information regarding long-term follow-up and an age-matched comparison group to highlight any differences between the two populations being compared.
Second, assessment of the impact of weakness on functional disability in terms of functionality, autonomy, and quality of life would also be interesting. If spasticity can cause contractures and pain with associated different degrees of functional limitation, it only partially explains the impairment of motor function (floor skills, standing, and walking). In fact, weakness contributes significantly to disability.4 Moreover, the surgery itself can impact weakness: the mean dose of ITB was 803.3 µg/day, and most patients had greater than 50% of the dorsal rootlets transected from L2 to S1. According to the International Classification of Functioning, Disability and Health, improvement in a domain, such as spasticity and pain ("structure and function"), could be associated with a gain in other aspects, such as trunk balance and sitting ("autonomy and participation").5,6
As it is likely that there are differences in this parameter in the two subgroups, a focus on monitoring weakness and the impact on head-trunk control in follow-up would therefore be recommended.
The authors report a difference in mean age at surgery without, in our opinion, sufficiently analyzing the risk of bias on the results. In the natural history of CP, spasticity varies with age, especially in GMFCS levels IV and V. It generally increases during the first 5 years of life and then decreases progressively until the age of 15 years.7 Consequently, the advantages and disadvantages of the need for surgical treatment of spasticity and the choice between ITB and SDR can vary with age. Variables such as the modulation and reversibility of therapeutic intervention should be considered very carefully.8
Finally, the authors reported the lack of an objective assessment of dystonia as a limitation of the work. SDR has been previously considered over ITB for the treatment of dystonia, with some disagreement. In the patient-screening phase, Schwartz et al. suggested the use of Walk-DMC, a 3D gait analysis test, to assess dynamic motor control in children with GMFCS level IV where the presence of dystonia might sway one to consider ITB over SDR for treatment.9 This strategy, for example, may be able to differentiate patients whose activation patterns predict insufficient control over their musculature to derive benefit from relief from their spasticity.
In patients who are candidates for ITB surgery, limits are often set of where to apex the catheter to bring benefit not only for spasticity but also for dystonia. Recently, Saenz et al. described an implanted ITB pump with the catheter tip placed prebrainstem, with excellent results in facial and trunk dystonia, which are usually treatment-resistant areas.10 Abdel Ghany et al. also demonstrated positive effects on activities of daily living of combined anterior and posterior SDR for treatment of mixed dystonia and spasticity in children with CP.11
In conclusion, with this letter, we want to underline the importance of a balanced choice of surgical options for the treatment of spasticity in these patients, also considering the preoperative axial control and the risk of worsening of weakness and initial skeletal deformity, the presence of dystonia, and the age at surgery as well as spasticity, pain, and caregiver burden.
Disclosures
The authors report no conflict of interest.
References
- 1↑
Mansur A, Morgan B, Lavigne A, et al. Comparison of intrathecal baclofen pump insertion and selective dorsal rhizotomy for nonambulatory children with predominantly spastic cerebral palsy. J Neurosurg Pediatr. 2022;30(2):217–223.
- 2↑
Tedroff K, Hägglund G, Miller F. Long-term effects of selective dorsal rhizotomy in children with cerebral palsy: a systematic review. Dev Med Child Neurol. 2020;62(5):554–562.
- 3↑
Handsfield GG, Williams S, Khuu S, Lichtwark G, Stott NS. Muscle architecture, growth, and biological remodelling in cerebral palsy: a narrative review. BMC Musculoskelet Disord. 2022;23(1):233.
- 5↑
Buizer AI, Martens BHM, Grandbois van Ravenhorst C, Schoonmade LJ, Becher JG, Vermeulen RJ. Effect of continuous intrathecal baclofen therapy in children: a systematic review. Dev Med Child Neurol. 2019;61(2):128–134.
- 6↑
Tacchino CM, Calevo MG, Pavanello M, Lanteri P, Bertamino M. Improved trunk and neck control after selective dorsal rhizotomy in children with spastic cerebral palsy. Childs Nerv Syst. 2021;37(2):351–352.
- 7↑
Lindén O, Hägglund G, Rodby-Bousquet E, Wagner P. The development of spasticity with age in 4,162 children with cerebral palsy: a register-based prospective cohort study. Acta Orthop. 2019;90(3):286–291.
- 8↑
Thomas SP, Addison AP, Curry DJ. Surgical tone reduction in cerebral palsy. Phys Med Rehabil Clin N Am. 2020;31(1):91–105.
- 9↑
Schwartz MH, Rozumalski A, Steele KM. Dynamic motor control is associated with treatment outcomes for children with cerebral palsy. Dev Med Child Neurol. 2016;58(11):1139–1145.
- 10↑
Saenz A, Grijalba M, Mengide JP, Argañaraz R, Ford F, Mantese B. Baclofen pump with pre-brainstem catheter tip placement: technical note and case series. Childs Nerv Syst. 2021;37(1):203–210.
- 11↑
Abdel Ghany WA, Nada M, Mahran MA, et al. Combined anterior and posterior lumbar rhizotomy for treatment of mixed dystonia and spasticity in children with cerebral palsy. Neurosurgery. 2016;79(3):336–344.
