A novel classification and its clinical significance in Chiari I malformation with syringomyelia based on high-resolution MRI

Impact of intradural abnormalities on symptoms and clinical outcomes in Chiari malformation

PURPOSE

This study aims to investigate the impact of intradural abnormalities on symptoms and clinical outcomes in Chiari malformation.

METHODS

A retrospective study was conducted on 189 patients with Chiari malformation who underwent posterior fossa decompression with duraplasty or tonsillectomy. Intradural abnormalities were categorized as arachnoid abnormalities, foramen of Magendie (FoM) obstruction, and tonsillar abnormalities. Clinical outcomes were assessed using the symptoms improvements, Chicago Chiari Outcome Scale (CCOS), complications and re-operation.

RESULTS

A total of 189 patients with Chiari malformation were included in the study. 79.4 % of the patients were female, with a mean age of 45.0 ± 10.7 years (range: 16-62 years). Common intradural abnormalities included arachnoid adhesions (68.3 %), obstruction of the foramen of Magendie (FoM) (50.3 %), and tonsillar hypertrophy (38.6 %). Obstruction of FoM was more frequently observed in patients with Valsalva provoked headaches (53.7 % vs. 12.8 %, p < 0.001), syringomyelia (93.7 % vs. 67.0 %, p < 0.001). CCOS scores (12.5 ± 2.3 vs. 13.3 ± 2.0, p = 0.027) and improved (53.7 % vs. 78.7 %, p = 0.001) were lower in the obstruction group. Tonsillar abnormalities were associated with higher incidence of Valsalva provoked headaches (61.6 % vs. 15.5 %, p < 0.001) and gait instability (43.8 % vs. 6.0 %, p < 0.001).

CONCLUSIONS

Intradural abnormalities, particularly obstruction of FoM and tonsillar abnormalities, are correlated with symptoms and clinical outcomes in Chiari malformation.

Effectiveness of Cerebellar Tonsillectomy Treatment for Revision Chiari Malformation Surgery: A Series of 63 Patients

BACKGROUND

Revision surgery for patients with persistent, recurrent, or progressive syringomyelia following Foramen Magnum Decompression for Chiari malformation with syringomyelia (CM-SM) is not uncommon and presents both strategic and technical challenges.

METHODS

We conducted a retrospective study including all patients who underwent revision Cerebellar Tonsillectomy (CTL) for CM-SM between 2003 and 2023. Additionally, we performed univariate and multivariate analyses to identify possible factors contributing to failed CTL outcomes.

RESULTS

Sixty-three consecutive patients (13 males; average age 45.86 ± 11.18 years) underwent surgical treatment for persistent (n = 29), progressive (n = 21), or recurrent (n = 13) syringomyelia, with an average interval of 65.57 ± 73.33 months (range: 3-480 months) between the two surgeries. Factors significantly associated with the effectiveness of the revision CTL included dural incision and tonsil manipulation during the first surgery, severe intradural adhesions during the revision CTL, and spinal cord atrophy before the revision CTL. Multivariate logistic regression revealed that dural incision (P = 0.031, odds ratio [OR] = 6.779, 95% confidence interval {CI} [1.187∼38.719]), tonsillar manipulation (P = 0.037, OR = 7.432, 95% CI [1.131∼48.835]), and severe intradural adhesions (P = 0.030, OR = 11.465, 95% CI [1.264∼103.967]) constituted risk factors significantly statistical associated with prognosis outcomes. Long-term follow-up (average 18.75 ± 6.86 months, range: 12-72 months) of revision CTL demonstrated clinical stabilization in 55.6% of cases for at least 1.5 years. The complication rate for revision CTL was 14.3% (n = 9).

CONCLUSIONS

Dural incision and tonsillar manipulation during the first surgery, spinal cord atrophy prior to revision CTL, and severe intradural adhesions during revision CTL are significant risk factors associated with poor prognosis in revision surgery for CM-SM.

Reliability and validity of the pediatric adaptation of the mJOA scale for evaluating cervical spine disorders

PURPOSE

The study aimed to evaluate the validity and reliability of the pediatric adaptation of the Japanese Orthopedic Association (mJOA) scale in pediatric patients with various cervical spine pathologies.

METHODS

Initial assessments were performed by a neurosurgeon, followed by an independent evaluation by a neurologist within 1-2 days to test inter-rater reliability. The same clinician assessed the same group of children using the adapted mJOA scale at different point in time (between 1 month and 1 year after the initial assessment) to test intra-rater reliability. For known-groups validity, the pediatric mJOA scale assessments were compared between two groups of pathologies with different prognosis. Concurrent validity was assessed against the McCormick scale, and convergent validity was tested by reassessing patients using the adult mJOA scale two or more years after the initial assessment by pediatric one.

RESULTS

A cohort of 169 pediatric patients aged 6 months to 18 years (mean age: 10 ± 4.6 years) with various cervical spine pathologies was recruited. Pathologies included atlanto-axial rotatory fixation (AARF), Chiari type I anomaly, congenital cervical spine scoliosis, atlanto-axial dislocation (AAD) and instability (AAI), cervical spine stenosis and trauma, and congenital cervicothoracic dislocations. The majority of patients underwent cervical spine surgery and were followed up for an average of 6.9 ± 2.97 years. The pediatric mJOA scale demonstrated high inter-rater reliability (r = 0.99, p < 0.0001) and strong intra-rater reliability (r = 0.82, p < 0.0001). Significant differences in pediatric mJOA scores were observed between patients with expected-intact neurological status and those with expected-pathological neurological status (p < 0.0001). The pediatric mJOA scale showed a strong correlation with the McCormick grading system (r = 0.97, p < 0.001) and good correlation with the adult mJOA scale during long-term follow-up (r = 0.82, p < 0.0001).

CONCLUSIONS

The pediatric version of the mJOA scale is a reliable and valid tool for assessing pediatric patients with cervical spine disorders. Its high reliability and validity support its use in both clinical practice and research.

Long-Term Impairment of the Blood-Spinal Cord Barrier in Patients With Post-Traumatic Syringomyelia and its Effect on Prognosis

STUDY DESIGN

Cohort study.

OBJECTIVE

The aim of this study was to explore the association between blood-spinal cord barrier (BSCB) markers and other factors associated with an unfavorable outcome among patients with post-traumatic syringomyelia (PTS) who achieved successful intradural adhesion lysis (IAL).

SUMMARY OF BACKGROUND DATA

Only approximately half of PTS patients receiving IAL have a favorable outcome.

PATIENTS AND METHODS

Forty-six consecutive patients with PTS and 19 controls (CTRL) were enrolled. All PTS patients underwent physical and neurological examinations and spinal magnetic resonance imaging before and 3 to 12 months after IAL. All patients underwent myelography before surgery. BSCB disruption was detected by increased intrathecal and serum concentrations of albumin, immunoglobulin (Ig)G, IgA, and IgM. A multivariable analysis was performed with a logistic regression model to identify factors associated with unfavorable outcomes. Receiver operating characteristic curves were calculated to investigate the diagnostic value of biomarkers.

RESULTS

The ages and general health of the PTS and CTRL groups did not differ significantly. QAlb, IGAQ, IGGQ, and IGMQ was significantly higher in PTS patients than in controls ( P =<0.001). The degree of intradural adhesion was significantly higher in the unfavorable outcome group than in the favorable outcome group ( P <0.0001). QAlb, immunoglobulin (Ig)AQ, IGGQ, and IGMQ was significantly correlated with clinical status ( R =-0.38, P <0.01; R =-0.47, P =0.03; R =-0.56, P =0.01; R =-0.43, P =0.05, respectively). Higher QAlb before surgery (odds ratio=2.66; 95% CI: 1.134-6.248) was significantly associated with an unfavorable outcome. The receiver operating characteristic curve analysis demonstrated a cutoff for QAlb higher than 10.62 with a specificity of 100% and sensitivity of 96.3%.

CONCLUSION

This study is the first to detect increased permeability and BSCB disruption in PTS patients. QAlb>10.62 was significantly associated with unfavorable clinical outcomes following intradural decompression.

LEVEL OF EVIDENCE

Level III-prognostic.

Role of Preoperative Albumin Quotient in Surgical Planning for Posttraumatic Syringomyelia: A Comparative Cohort Study

OBJECTIVE

Surgical procedures for patients with posttraumatic syringomyelia (PTS) remain controversial. Until now, there have been no effective quantitative evaluation methods to assist in selecting appropriate surgical plans before surgery.

METHODS

We consecutively enrolled PTS patients (arachnoid lysis group, n = 42; shunting group, n = 14) from 2003 to 2023. Additionally, 19 intrathecal anesthesia patients were included in the control group. All patients with PTS underwent physical and neurological examinations and spinal magnetic resonance imaging preoperatively, 3-12 months postoperatively and during the last follow-up. Preoperative lumbar puncture was performed and blood-spinal cord barrier disruption was detected by quotient of albumin (Qalb, cerebrospinal fluid/serum).

RESULTS

The ages (p = 0.324) and sex (p = 0.065) of the PTS and control groups did not differ significantly. There were also no significant differences in age (p = 0.216), routine blood data and prognosis (p = 0.399) between the arachnoid lysis and shunting groups. But the QAlb level of PTS patients was significantly higher than that of the control group (p < 0.001), and the shunting group had a significantly higher QAlb (p < 0.001) than the arachnoid lysis group. A high preoperative QAlb (odds ratio, 1.091; 95% confidence interval, 1.004-1.187; p = 0.041) was identified as the predictive factor for the shunting procedure, with the receiver operating characteristic curve showing 100% specificity and 80.95% sensitivity for patients with a QAlb > 12.67.

CONCLUSION

Preoperative QAlb is a significant predictive factor for the types of surgery. For PTS patients with a QAlb > 12.67, shunting represents the final recourse, necessitating the exploration and development of novel treatments for these patients.

Individualized Functional Decompression Options for Adult Chiari Malformation With Syringomyelia and A Novel Scale for Syringomyelia Resolution: A Single-Center Experience

OBJECTIVE

To compare outcomes of posterior fossa bony decompression alone (PFD) versus PFD with duraplasty (PFDD) versus PFDD with additional obex exploration (PFDDO) in patients with Chiari malformation type I (CMI) combining syringomyelia.

METHODS

Clinical records of adult patients who underwent decompressions from 2014 to 2022 were retrospectively analyzed. The decompression procedure was individualized based on the cerebrospinal fluid pulse in the surgical field. The Chicago Chiari Outcome Scale (CCOS) was used to assess the prognosis of the patients and a novel syringomyelia resolution scale, based on 3-dimensional volume, was introduced. The percentage change in the cervical syrinx volume was classified as follows by resolution: ≥ 70%, 30%-70%, and < 30%.

RESULTS

Seventy-eight individuals were enrolled, of which 22, 20, and 36 underwent PFD, PFDD, and PFDDO, respectively. The three decompression groups had no significant difference in the preoperative characteristics and postoperative prognosis. Multivariate analyses revealed that better CCOS was significantly correlated with younger age at surgery (p = 0.018), syrinx originated from lower cervical levels (p = 0.037), narrower preoperative cerebral aqueduct (p = 0.005), and better syrinx volume resolution (p = 0.004). Additionally, a better cervical syrinx volume resolution was significantly correlated with higher CCOS (p = 0.017), narrower cerebral aqueduct (p = 0.035), and better tonsillar descent resolution (p = 0.007).

CONCLUSION

Individualized functional decompression induced an equal effect on CCOS and syrinx volume resolution for all CMI patients with syringomyelia. Our syringomyelia resolution scale facilitates communication and prediction of CMI prognosis.

A Novel Craniocervical Junction Compression Severity Index-Based Grading System for Multidirectional Quantification of the Biomechanics at Foramen Magnum of Chiari Malformation Type I

Objective  This study aimed to establish a novel grading system, based on the craniovertebral junction compression severity index (CVJCSI) for multidirectional quantification at the foramen magnum plane for Chiari malformation type I (CMI). Methods  The CVJCSI grading system was established to stratify patients based on the ventral (modified clivoaxial angle < 138°), dorsal (tonsil herniation), and central (brainstem herniation) CVJ (craniovertebral junction) compression, the CVJCSI grading system was established to stratify patients. The optimal surgical method for each grade was recommended by intragroup comparisons regarding the efficacy of the three operations. Finally, according to the CVJCSI grading system, a prospective validation trial was performed and surgically treated for internal validation. Results  Based on the retrospective study ( n  = 310), the CVJCSI included six grades: I: syrinx alone without compression; II: dorsal compression; III: dorsal and central compression; IV: ventral compression; V: dorsal and ventral compression; and VI: ventral, dorsal, and central compression. Among all available variables, only the CVJCSI and surgical methods significantly affected the CCOS. The CCOS scores, overall and for each CVJCSI grade, increased in the prospective cohort ( n  = 42) compared with that in the retrospective analysis. Conclusions  The CVJCSI can be used to stratify CMI patients. The higher the CVJCSI grade, the more severe the CVJ compression and the worse posterior fossa deformity. Meanwhile, the CVJCSI was negatively correlated with the CCOS. The lower the CVJCSI grade, the better the response to surgery, and the less-invasive surgical procedures were warranted. Finally, the prospective cohort study validated the proposed CVJCSI-based surgical protocols.

Three-Dimensional Volumetric Magnetic Resonance Imaging Analysis of Syringomyelia Evolution After Posterior Fossa Decompression for Chiari Malformation Type1

OBJECTIVE

This study aims to introduce a method of three-dimensional (3D) volume magnetic resonance imaging (MRI) measurements to evaluate the evolution of syringomyelia (SM) in adults with Chiari malformation type 1 (CM-1) after posterior fossa decompression (PFD), to provide reproducible and accurate measurements.

METHODS

Radiologic and clinical data were obtained for 28 patients. MRI 3D syrinx volumes were evaluated by 2 observers using Philips Healthcare Tumor Tracking tool.

RESULTS

The mean SM preoperative volume was 9.1 ± 15.3 cm3 versus 4.6 ± 8.7 cm3 postoperatively, corresponding to a volume variation reduced by -50% ± 33.4%. A total of 21 patients (75%) showed >25% reduction in SM volume postoperatively and 25 patients (89.2%) showed good to excellent postoperative clinical outcomes. Very high interobserver and intraobserver agreement was noted for 3D volumetric analysis with Cohen weighted κ coefficients (0.899-0.991). A negative correlation was found between the number of involved metameres and the postoperative SM volume reduction (Pearson correlation coefficient = 0.378; P = 0.047). Patients with better clinical outcomes had fewer syrinx septae (F = 8.830; P = 0.001). Similarly, better syrinx volume reduction was associated with fewer septae (F = 1.554; P = 0.233). A positive relationship was observed between clinical outcomes and postoperative syrinx volume reduction (F = 1.554; P= 0.233), with data similar to the reported literature.

CONCLUSIONS

This study shows that 3D volume measurement of the syrinx cavity on MRI is a reproducible and accurate method to assess the postoperative evolution of SM in CM-1 after PFD. Most patients (75%) showed a reduction of SM volume, with a mean volume decrease of 50%. The reliability is yet to be validated in further larger studies.

A novel scoring system for assessing adult syringomyelia associated with CM I treatment outcomes

BACKGROUND

A specific scoring system for syringomyelia is lacking. Our objective was to investigate the value of a novel scoring system (Syringomyelia Outcome Scale of Xuanwu hospital, SOS-XW) in assessing surgical outcomes in the treatment of syringomyelia (SM) associated with Chiari malformation type I (CM I).

METHODS

A quantitative evaluation system (SOS-XW) of SM includes 4 parameters: pain (P), sensation (S), movement (M), and syringomyelia tension index (STI). The clinical data of 88 patients with CM I-related syringomyelia treated by foramen magnum and Magendie dredging (FMMD) from January 2018 to January 2019 were retrospectively analysed with a mean follow-up of 14.3 months, and the SOS-XW score was used to assess the efficacy.

RESULTS

The higher the SOS-XW score, the more severe was the SM and related symptoms. The mean preoperative score was 5.97, and the postoperative score was 2.66. The symptom improvement rates were 77.78% for P, 69.01% for S, 31.82% for M, and 95.06% for the syringomyelia tension index (STI). The symptom improvement rate of the PSM score was weakly correlated with the improvement rate of STI, R² = 0.0016. The percentage of PSM (P + S + M) improvement was lower in patients with an STI of 0. The postoperative SOS-XW score was positively correlated with the postoperative JOA score, R² = 0.8314. The positive detection rate of SOS-XW was higher than that of the JOA score.

CONCLUSIONS

To evaluate the surgical procedure efficacy in the treatment of syringomyelia, the SOS-XW score can provide a more objective, detailed, and comprehensive analysis, especially STI. A reduction in STI is the practical standard for assessing the effectiveness of surgery.

Fourth ventricle stent placement for treatment of type I Chiari malformation in children

INTRODUCTION

Type I Chiari malformation (CM-I) is a common congenital malformation, often accompanied by syringomyelia. Obstruction of CSF circulation in the foramen magnum is the reason for the formation of the syringomyelia. Fourth ventricle stenting (FVS) could ensure the CSF flow from the fourth ventricle, which might represent an effective approach to achieve syringomyelia relief.

METHODS

We have reviewed four cases of CM-I children who received FVS implantation from November 2021 to July 2022. Each of the patients underwent FMD. The ventricular catheter of an Ommaya reservoir (Medtronic, Inc.) was used as a stent. Duraplasty was performed with autologous fascia. Cervical MRI rechecks were routinely done 3 months later, and the clinical symptoms were followed up.

RESULTS

Four children received FVS, including one boy and three girls, aged from 12 months to 10 years, with a mean age of 6.8 years. No major complication occurred. The syringomyelia or hydrocephalus in each patient were all attenuated, as observed on the reexamination MRI images. During the follow-up time with a mean of 10.8 months, no patient had new symptoms.

CONCLUSION

FVS is an effective and safe method for operation of CM-1 in children. The indications of FVS include redo-FMD, difficulties to ensure post-FMD CSF circulation patency at the foramen magnum and with obstructive hydrocephalus. A long-term follow-up duration is necessary.

Chiari Type 1 Malformation and Syringomyelia in Children: Classification and Treatment Options

Chiari type 1 malformation (CIM) is defined as tonsillar ectopia of >5 mm, while syringomyelia (SM) is defined as a cerebrospinal fluid (CSF)-filled cavity larger than 3 mm dissecting the spinal cord. Over the last decades, our understanding of these pathologies has grown; however, many controversies still exist almost in every aspect of CIM and SM, including etiology, indication for treatment, timing of treatment, surgical technique, follow-up regime, and outcome. This chapter provides a comprehensive overview on different aspects of CIM and SM and on the still existing controversies, based on the evidence presently available. Future directions for clinical research concerning CIM and SM treatment and outcome are elaborated and discussed as well.

Relationship Between Syrinx Resolution and Cervical Sagittal Realignment Following Decompression Surgery for Chiari I Malformation Related Syringomyelia Based on Configuration Phenotypes

OBJECTIVE

Combined with different configuration types of syringomyelia, to analyze the correlation between syrinx resolution and changes in cervical sagittal alignment following Foramen magnum and Magendie dredging (FMMD) for syringomyelia associated with Chiari I malformation (CM-I), and to further explore the respective relationship with clinical outcome.

METHODS

A consecutive series of 127 patients with CM-I and syringomyelia who underwent FMMD in our center met the inclusion criteria of this study. Their clinical records and radiologic data were retrospectively reviewed. The Japanese Orthopedic Association (JOA) scoring system and the Chicago Chiari Outcome Scale (CCOS) were used to evaluate the surgical efficacy. The phenotypes of syringomyelia and the clinical characteristics of the patients were analyzed according to grouping by cervical curvature at baseline.

RESULTS

The preoperative straight or kyphotic cervical alignment is more common in the moniliform syrinx. After surgery, the syrinx resolution and cervical sagittal realignment in the moniliform group are more obvious, and the corresponding prognosis is relatively better. Spearman correlation analysis showed that the ΔS/C ratio (the change ratio of syrinx/cord) was positively correlated with the CCOS (p = 0.001, r = 0.897) and ΔC2-7A (the change of lower cervical angle) (p = 0.002, r = 0.560). There was also a correlation between the ΔJOA score (the change rate of the JOA score) and ΔC2-7A (p = 0.012, r = 0.467).

CONCLUSION

After decompression surgery, syrinx resolution may coexist with the changes in the subaxial lordosis angle, especially for syrinx in moniliform type, and the relationship between syrinx resolution and cervical sagittal realignment might be valuable for evaluating the surgical outcome.

Neurological deterioration after posterior fossa decompression for adult syringomyelia: Proposal for a summarized treatment algorithm

Background

Patients with syringomyelia who present with new neurological symptoms after posterior fossa decompression (PFD) are not uncommon. However, systematic reports on different pathologies are few in the literature.

Objective

The purpose of this study was to summarize our experience for failed PFD.

Methods

Between January 2015 and December 2019, 85 consecutive failed PFD patients were identified. The neurological courses were summarized with Klekamp J (KJ) or mJOA score system for all patients. Long-term results were summarized with Kaplan-Meier method.

Results

Twenty-eight consecutive patients underwent FMDD (Foramen magnum and foramen of Magendie dredging) (Group I), extradural PFD and manipulation of tonsil was significantly associated with lower failure rates. Twenty patients underwent craniocervical fixation (Group II), nine underwent local spinal segment decompression (Group III), six underwent CSF diversion procedures, and one were treated for persistent pain by radiofrequency. Neuropathic pain was most significantly improved in Group I while swallowing improved in Group II within 1 year after the surgery. In the long term, late postoperative deterioration-free possibility in Group II was better than in Group I. All patients in Group III improved (P = 0.0088). Six cases of CSF diversion procedures were relieved in a short time. Pain in one patient persisted after PFD, and trial of radiofrequency failed.

Conclusion

Not only does the recurrent cerebrospinal fluid flow obstruct the foramen magnum, but also spinal pathologies and craniocervical instabilities may occur. This study provides the largest summarized clinical experience that may assist surgeons with different therapeutic decisions for failed PFD.

Spinal Obstruction-Related vs. Craniocervical Junction-Related Syringomyelia: A Comparative Study

Background

No prior reports have focused on spinal cord injury (SCI) characteristics or inflammation after destruction of the blood–spinal cord barrier by syringomyelia. This study aimed to determine the differences in syringomyelia-related central SCI between craniocervical junction (CCJ) syringomyelia and post-traumatic syringomyelia (PTS) before and after decompression.

Methods

In all, 106 CCJ, 26 CCJ revision and 15 PTS patients (mean history of symptoms, 71.5 ± 94.3, 88.9 ± 85.5, and 32.3 ± 48.9 months) between 2015 and 2019 were included. The symptom course was analyzed with the American Spinal Injury Association ASIA and Klekamp–Samii scoring systems, and neurological changes were analyzed by the Kaplan–Meier statistics. The mean follow-up was 20.7 ± 6.2, 21.7 ± 8.8, and 34.8 ± 19.4 months.

Results

The interval after injury was longer in the PTS group, but the natural history of syringomyelia was shorter (p = 0.0004 and 0.0173, respectively). The initial symptom was usually paraesthesia (p = 0.258), and the other main symptoms were hypoesthesia (p = 0.006) and abnormal muscle strength (p = 0.004), gait (p < 0.0001), and urination (p < 0.0001). SCI associated with PTS was more severe than that associated with the CCJ (p = 0.003). The cavities in the PTS group were primarily located at the thoracolumbar level, while those in the CCJ group were located at the cervical-thoracic segment at the CCJ. The syrinx/cord ratio of the PTS group was more than 75% (p = 0.009), and the intradural adhesions tended to be more severe (p < 0.0001). However, there were no significant differences in long-term clinical efficacy or peripheral blood inflammation markers (PBIMs) except for the red blood cell (RBC) count (p = 0.042).

Conclusion

PTS tends to progress faster than CCJ-related syringomyelia. Except for the RBC count, PBIMs showed no value in distinguishing the two forms of syringomyelia. The predictive value of the neutrophil-to-lymphocyte ratio for syringomyelia-related inflammation was negative except in the acute phase.

Syrinx reduction due to spontaneous spinal cord tear: demonstration on 3 T MRI and review of the literature

A holocord syringomyelia due to Chiari 1.5 malformation (CM) in a 12-year-old girl was serially imaged with 3 T MRI over 4 years. The serial MRI showed reduction in size of the syrinx, without any surgical intervention or CM improvement, but rather due to spontaneous spinal cord tear. The tear was clearly demonstrated by evidence of flow signal across the tear between syrinx and subarachnoid space at the upper thoracic level. The tear showed spontaneous closure at follow-up. A medullary tear has been described in the adult population as one of the putative causes of spontaneous syringomyelia reduction, but its clear demonstration with modern high-resolution MRI has not been reported in the paediatric population. Moreover, this is the first reported case of syrinx reduction due to spontaneous fissuration in a paediatric patient.