Letter to the Editor. Intrathecal baclofen pump insertion versus selective dorsal rhizotomy

Anna Bruna RonchettiIRCCS Istituto Giannina Gaslini, Genoa, Italy

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Marta BertaminoIRCCS Istituto Giannina Gaslini, Genoa, Italy

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Chiara Maria TacchinoIRCCS Istituto Giannina Gaslini, Genoa, Italy

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Paolo MorettiIRCCS Istituto Giannina Gaslini, Genoa, Italy

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Marco PavanelloIRCCS Istituto Giannina Gaslini, Genoa, Italy

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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):217223.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 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):554562.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 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.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Graham HK, Rosenbaum P, Paneth N, et al. Cerebral palsy. Nat Rev Dis Primers. 2016;2:15082.

  • 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):128134.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 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):351352.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 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):286291.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Thomas SP, Addison AP, Curry DJ. Surgical tone reduction in cerebral palsy. Phys Med Rehabil Clin N Am. 2020;31(1):91105.

  • 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):11391145.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 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):203210.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 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):336344.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
Ann MansurUniversity of Toronto, ON, Canada

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Darcy FehlingsHolland Bloorview Kids Rehabilitation Hospital, University of Toronto, ON, Canada

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Alexander G. WeilSainte-Justine University Hospital, Montréal, QC, Canada

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George M. IbrahimUniversity of Toronto, ON, Canada
Hospital for Sick Children, Toronto, ON, Canada

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Response

We thank Ronchetti et al. for a thoughtful response to our article on the outcomes of ITB and SDR for nonambulatory patients with spastic diplegic and quadriplegic CP.

The authors first note that our work primarily focuses on short- to medium-term outcomes (mean time to last follow-up 18.7 ± 5.9 months) and that a longer-term follow-up would capture a greater breadth of complications, including scoliosis and hip dislocation, that can occur years after surgical interventions such as SDR and ITB treatment. Indeed, we raise this point in our discussion and highlight some of the literature on the evolution in complication profiles after SDR for patients with spastic CP.1 We completely agree with Ronchetti and colleagues that an ideal study would capture short-, medium-, and long-term outcomes for this complex patient population to best discern the longitudinal effects of each surgical intervention and to better tailor therapies at each time point in a patient’s trajectory. Not only do the complications differ in each time frame, but also we see that the benefits of each intervention can persist to varying degrees in the delayed phase.2

We strongly agree that the issue of weakness and its relation to head-trunk control warrants further attention. In an analysis of trunk control on gross motor function, Choi and colleagues found that impairments in trunk control are significantly worse for individuals who function at higher GMFCS levels, compared with those with diplegic or hemiplegic CP.3 Appreciation of a child’s true motor function can be challenging in this patient population as spasticity is known to mask weakness, and, by extension, surgical interventions that reduce spasticity can then unmask a child’s underlying motor weakness particularly as it relates to head control.2 Such an analysis is further confounded by surgical interventions that are applied to children with mixed CP that directly result in weakness, such as combined motor and sensory rhizotomy.4 As our colleagues point out, heterogeneity in the surgical treatments (e.g., catheter position, percentage of nerve roots transected, dorsal vs dorsal, and ventral rhizotomy) contributes meaningfully to outcomes. Ultimately, the child’s and their family’s quality of life are likely better markers of surgical outcome than individual metrics, and further work is required to assess the impact of weakness and head-trunk control and the influence of different surgical approaches on quality of life.

One of the most important findings of our study is the baseline difference in patient demographics prior to surgical intervention. Although we sought to include children with predominantly spastic quadriplegic CP, we showed that there is considerable heterogeneity within this population, and clinician bias intrinsically informs therapeutic choices. For instance, younger children underwent SDR and those with more severe dystonia were more likely to undergo ITB. While these findings may seem self-evident, they have critical implications for the design of inclusion criteria for future prospective studies in this population. A child’s needs (including reduction in spasticity, relief from pain, deformity correction, etc.) will naturally evolve with age. The appropriate surgical therapy is the one that provides the greatest likelihood for addressing a particular individualized need at the appropriate time. As a result, there is a need to be highly selective in future prospective studies to define the population of nonambulatory children with CP for whom there is true equipoise in surgical decision-making between SDR and ITB.

In essence, the many thoughtful discussion points raised by our colleagues speak to the need for high-quality, prospective, longitudinal data, which of course could not be captured in our retrospective review. We also appreciate the importance of value-based decision-making, which takes into account other considerations, such as the reversibility of the interventions. We look forward to future collaborative efforts to disentangle the complex interactions between spasticity, dystonia, truncal control, weakness, developmental stage, and age and their impact on quality of life in CP. These efforts will advance our understanding of the roles of SDR and ITB in improving the lives of affected children and families.

References

  • 1

    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):554562.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Thomas SP, Addison AP, Curry DJ. Surgical tone reduction in cerebral palsy. Phys Med Rehabil Clin N Am. 2020;31(1):91105.

  • 3

    Choi YE, Jung HR, Kim JH. Comparison of trunk control on gross motor function and topography in children with spastic cerebral palsy. J Korean Soc Phys Med. 2019;14(4):4553.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4

    Ghany WAA, 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):336344.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
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Images from Chiang et al. (pp 595–601).

  • 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):217223.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 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):554562.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 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.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Graham HK, Rosenbaum P, Paneth N, et al. Cerebral palsy. Nat Rev Dis Primers. 2016;2:15082.

  • 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):128134.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 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):351352.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 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):286291.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Thomas SP, Addison AP, Curry DJ. Surgical tone reduction in cerebral palsy. Phys Med Rehabil Clin N Am. 2020;31(1):91105.

  • 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):11391145.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 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):203210.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 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):336344.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 1

    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):554562.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Thomas SP, Addison AP, Curry DJ. Surgical tone reduction in cerebral palsy. Phys Med Rehabil Clin N Am. 2020;31(1):91105.

  • 3

    Choi YE, Jung HR, Kim JH. Comparison of trunk control on gross motor function and topography in children with spastic cerebral palsy. J Korean Soc Phys Med. 2019;14(4):4553.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 4

    Ghany WAA, 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):336344.

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation

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