Intrathecal baclofen for hereditary spastic paraplegia (HSP)

  • PDF / 180,475 Bytes
  • 3 Pages / 595.276 x 790.866 pts Page_size
  • 77 Downloads / 228 Views

DOWNLOAD

REPORT


LETTER TO THE EDITOR

Intrathecal baclofen for hereditary spastic paraplegia (HSP) Ian C. Coulter 1

&

Laura Nanna Lohkamp 1 & George M. Ibrahim 1

Received: 4 June 2020 / Accepted: 8 June 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020

Dear Editor: We recently published a systematic review on the role of selective dorsal rhizotomy (SDR) in conditions of genetic etiology causing spasticity, including hereditary spastic paraplegia (HSP). Given the expanding role of SDR and the paucity of outcome data for such patients, we felt that a summary of the available literature was timely. We reported that SDR was effective at reducing spasticity; however, functional outcomes were variable. SDR was the specific focus of our analysis, and as such, alternative surgical treatments such as intrathecal baclofen (ITB) were not considered but nevertheless warrant the readership’s attention to facilitate a balanced understanding of the options available—as alluded to by one of the article’s reviewers. Baclofen is a GABAB agonist with antispastic effects. It was introduced as an intrathecal treatment in 1984 by Penn and Kroin for refractory spasticity of spinal and supraspinal origin. Many studies have since confirmed its safety and effectiveness. As well as case reports illustrating its efficacy in conditions with spasticity of genetic origin such as NiemannPick disease type C and X-linked adrenoleukodystrophy, data reporting the use of ITB for HSP is gradually accumulating. Using a similar search strategy outlined in our recent review, we identified 11 studies which assessed ITB treatment for 58 patients with HSP (Table 1) [1–5]. Of these patients, one child (aged 10–14) received the treatment [5]. The HSP phenotype is progressive and includes an unpredictable course of lower limb spasticity, impairment of gait, and ambulation. Therefore, reducing spasticity while maintaining strength to preserve mobility in ambulatory patients or easing care in non-ambulatory patients have been the goals of therapy. The outcomes of these studies should be interpreted with

* Ian C. Coulter [email protected] 1

Division of Neurosurgery, The Hospital for Sick Children, 555 University Ave, Suite 1503, Toronto, ON M5G 1X8, Canada

caution, as considerable heterogeneity is reported in the response to a preoperative test dose of ITB (30–90% response rate in cohorts > 3 patients). Presumably, only individuals that responded to the test dose subsequently underwent pump implantation, and consequently, the majority of patients experienced benefit, be it symptomatic relief or functional gain. Accordingly, most studies have reported outcomes related to relief of lower limb spasticity, walking performance, and complications. The modified Ashworth Scale score and other heterogenous parameters were employed, which limits quantitative inter-study comparison of outcomes. Some studies focused on gait improvement, considering it a more precise and appropriate outcome measure in HSP patients than the conventional evaluation of spasticity red