Original ArticleSyringo-Subarachnoid Shunt for the Treatment of Persistent Syringomyelia Following Decompression for Chiari Type I Malformation: Surgical Results
Introduction
Chiari I malformation, defined as a caudal displacement of the cerebellar tonsils, is associated with syringomyelia in 35%–75% of cases.1, 2, 3 The first-line surgical treatment for the Chiari–syrinx complex is foramen magnum decompression (FMD), although some authors advocate up-front shunting of the syrinx using a syringo-subarachnoid shunt (SSS).4, 5 The syrinx persists after FMD in up to 66% of patients.1 Patients with an increase in syrinx size and worsening of neurologic symptoms after FMD have also been described.2, 3, 6 The surgical treatment of persistent, recurrent, or increasing syringomyelia is still being debated. Some advocate re-decompression and duraplasty with or without cerebellar tonsils shrinking or resection, whereas others suggest an adhesiolysis of the arachnoidea at the region of the foramen magnum or a shunting procedure (syringopleural or syringo-subarachnoid shunt).1, 2, 3, 7, 8, 9 In an international survey regarding the management of Chiari I malformation and syringomyelia, the majority of respondents favored shunting of the syrinx to the subarachnoid space in cases of persistent or progressive syrinx after FMD.10 Despite what seems to be a common practice, to our knowledge, no series exists evaluating and focusing on the surgical outcome of SSS. In a small case series,11 syringopleural shunting was shown to be a valid option for refractory syringomyelia secondary to various pathologies (e.g., Chiari I malformation, posttraumatic, postinflammatory).
The aim of the current study is to report our experience treating patients with SSS for Chiari I malformation–related syrinx—either concurrently with FMD or after FMD—for persistent, recurrent, or increasing syrinx.
Section snippets
Methods
The study protocol was approved by the local ethics committee. Patient consent was not sought for this retrospective study, because it is not necessary according to local ethical guidelines. Of 71 consecutive patients undergoing FMD for Chiari I malformation at our department between 2003 and 2016, 21 patients (29.6%) underwent SSS, either concurrently with the FMD or at a later stage. Generally, SSS was the treatment of choice for syrinxes that were extreme at presentation or significantly
Results
We included 21 consecutive patients in the study; 16 patients underwent SSS for persistent, recurrent, or increasing syrinx after FMD, and 5 patients underwent concurrent SSS and FMD for an initially symptomatic and large syrinx. The patient group included 14 females (66.7%) and 7 males (33.3%) with an average age of 16.3 ± 15.4 years (median, 13 years; range, 3–61 years) at the time of SSS insertion. The patients' demographic and clinical data are presented in Table 2. Median clinical
Discussion
In this study, we reviewed 21 patients who underwent SSS for persistent, recurrent, or increasing syrinx after FMD for Chiari I malformation, or SSS combined with FMD for Chiari I malformation and an initially symptomatic and extensive syrinx. To our knowledge, this series is the first to evaluate the outcome of SSS in these patients. The significant improvement of the mJOA score by 11.8% and the significant radiologic improvement of the syrinx size by 76.3% indicates that this procedure is a
Conclusion
Considering on our results, SSS should be recommended as one of the major surgical options for persistent, recurrent, or increasing syrinx following FMD for Chiari I malformation. SSS seems to improve neurologic and radiologic outcomes for these patients. SSS for persistent, recurrent, or increasing syrinx following FMD for Chiari I malformation is a safe and effective surgical treatment when performed selectively by an experienced neurosurgeon.
Acknowledgment
The authors thank Adina Sherer for the medical editing of this manuscript.
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Long-term outcome and prognostic factors of syringo-subarachnoid shunt for syringomyelia
2023, Journal of Clinical NeuroscienceShort-Term and Long-Term Complications Associated with Posterior Fossa Decompression for Chiari Malformation
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2023, Neurosurgery Clinics of North AmericaCitation Excerpt :Shunting procedures have been proposed in case of extensive arachnoiditis or repeated failures in a recent study of Knafo and colleagues, whereas revision of duraplasty at the level of foramen magnum is the first-line treatment.42 Syrinx to subarachnoid shunting41 as well as syringo-subarachnoid-peritoneal shunt was also described as an option in patients who have not responded to the primary treatment.41 The correlation between hydrocephalus and CM-I has been debated since the first descriptions.43
Influence of clivo-axial angle on outcome after foramen magnum decompression in adult symptomatic Chiari type 1 malformation
2022, Clinical Neurology and NeurosurgeryCitation Excerpt :The preoperative presence of syringomyelia and the rate of persistent syringomyelia following FMD were both higher in the unfavorable outcome group, although without statistical significance in association with the outcome. Our findings agreed with those of Soleman et al. [18,22] reporting that 30% of patients undergoing FMD for syringomyelia-CM1 complex showed persistent, progressive, or recurrent syringomyelia. However, contrary to our findings, the CXA was not shown to be associated with the outcome in his analysis.
Comparative Assessment of Three Posterior Fossa Decompression Techniques and Evaluation of the Evidence Supporting the Efficacy of Syrinx Shunting and Filum Terminale Sectioning in Chiari Malformation Type I. A Systematic Review and Network Meta-Analysis
2021, World NeurosurgeryCitation Excerpt :Both SSS and SPS allow direct syrinx drainage rather than resolving the subarachnoid space obstruction within the CCJ. In their study, Soleman et al.11,46 strongly encourage performing SSS after PFD in case of persistent, recurrent, or increasing syrinx cavity. Hida et al.47 showed a higher syringomyelia improvement rate and shorter syrinx reduction time in the SSS group than in the decompression group, concluding that SSS could be superior to suboccipital decompression in patients with syringomyelia, especially with extended ones.
Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.