Surgical Management after Chiari Decompression Failure: Craniovertebral Junction Revision versus Shunting Strategies.

Revision surgery after posterior fossa decompression for Chiari malformation is not uncommon and poses both strategic and technical challenges. We conducted a single-center retrospective cohort study including all adult patients who underwent revision surgery after posterior fossa decompression for Chiari type I malformation between 2010 and 2019. Among 311 consecutive patients operated on for Chiari malformation at our institution, 35 patients had a least one revision surgery with a mean follow-up of 70.2 months. Mean delay for revision was 28.8 months. First revision surgery was performed at the level of the foramen magnum in 25/35 cases and consisted in duraplasty revision in all cases, arachnolysis (51.4%), additional bone decompression (37.1%), tonsillar coagulation or resection (25.7%), 4th ventricle to cervical subarachnoid spaces shunt (5.7%). Most repeat revisions consisted in CSF diversion procedures, with either ventriculo-peritoneal or syringo-peritoneal shunts. Mean number of interventions per patient was 3.2, with 22.9% of patients undergoing 4 or more surgeries. Based on our experience, we propose that revision at the level of the foramen magnum should be considered as a first-line strategy for Chiari decompression failure. Shunting procedures can be performed in case of extensive arachnoiditis or repeated failures.

Reintervention rate of arachnolysis versus shunting for nonforaminal syringomyelia.

OBJECTIVE: Surgical treatment for nonforaminal syringomyelia related to spinal arachnoiditis is still controversial. The authors sought to assess respective outcomes and rates of reintervention for shunting and spinal cord untethering (arachnolysis) in spinal arachnoiditis with syringomyelia. METHODS: This retrospective cohort study was conducted at a single reference center for syringomyelia. Patients undergoing arachnolysis and/or shunting interventions for nonforaminal syringomyelia were screened. RESULTS: The study included 75 patients undergoing 130 interventions. Arachnolysis without shunting was performed in 48 patients, while 27 patients underwent shunting. The mean follow-up between the first surgery and the last outpatient visit was 65.0 months (range 12-379 months, median 53 months). At the last follow-up, the modified McCormick score was improved or stabilized in 83.4% of patients after arachnolysis versus 66.7% after shunting. Thirty-one (41.3%) patients underwent reintervention during follow-up, with a mean delay of 33.2 months. The rate of reintervention was 29.2% in the arachnolysis group versus 63.0% in the shunting group (chi-square = 8.1, p = 0.007). However, this difference was largely driven by the extension of the arachnoiditis: in patients with focal arachnoiditis (≤ 2 spinal segments), the reintervention rate was 21.6% for arachnolysis versus 57.1% for shunting; in patients with extensive arachnoiditis, it was 54.5% versus 65.0%, respectively. Survival analysis assessing the time to the first reintervention demonstrated a better outcome in both the arachnolysis (p = 0.03) and the focal arachnoiditis (p = 0.04) groups. CONCLUSIONS: Arachnolysis led to fewer reinterventions than shunting in patients with nonforaminal syringomyelia. There was a high risk of reintervention for patients with extensive arachnopathies, irrespective of the surgical technique.

Management of Chiari malformation type I and syringomyelia during pregnancy and delivery.

OBJECTIVE: Although a recurrent question in clinical practice, the management of Chiari malformation type I (CMI) and/or syringomyelia during pregnancy and delivery is still debated. The aim of this study was to investigate the modalities of delivery and anesthesia in women presenting with CMI and/or syringomyelia at a national reference center, and to question their potential role in the natural history of these conditions. STUDY DESIGN: We conducted a retrospective cohort study using a standardized questionnaire, a customized clinical severity score and data from medical records. RESULTS: 83 patients were included in the final analysis: 32 had CMI without syringomyelia, 27 had CMI with syringomyelia and 24 had non-foraminal syringomyelia. Most patients (55/83) were not diagnosed at the time of their pregnancy, 12 had surgery before being pregnant and 16 were diagnosed but not operated. Most women underwent vaginal delivery (62 %) and neuraxial (i.e. epidural or spinal) anesthesia (69 %). However, the proportion of cesarean procedures increased to 53.6 % and even 83.3 % when considering only patients already diagnosed or operated on, respectively. Nonetheless, neither vaginal compared to cesarean delivery (change in clinically severity score: -1.5 ± 0.4 versus -0.9 ± 0.4, p = 0.4) nor neuraxial compared to general anesthesia (-1.2 ± 0.3 versus -1.5 ± 0.6, p = 0.7) were associated with increased clinical deterioration. CONCLUSION: Although individual evaluation is mandatory, this study supports that neither delivery nor anesthesia modalities affect the natural history for the vast majority of patients with CMI and/or syringomyelia.

Prospective Follow-up of Intramedullary Slitlike Cavities: A Consecutive Series of 48 Patients.

Object: Predicting whether intramedullary slitlike cavity (SC) will worsen over time or remain stable is an outstanding clinical challenge. The aim of this study was to identify early features of SC (clinical and magnetic resonance imaging [MRI] findings). Methods: We prospectively included all patients referred to our institution following the discovery of a SC and divided them in two groups: typical SC (defined as a cavity spanning fewer than three vertebrae, not enlarging the spinal cord, and located at the midline between the anterior third and posterior two-thirds of the spinal cord) or atypical SC (all others). Clinical evolution and changes in MRI features were evaluated during follow-up. In some patients, diffusion tensor imaging was performed and cervical cord cross-sectional area was analyzed. Results: A total of 48 consecutive patients were included in the study. The mean follow-up was 58 months. Of the seven patients presenting with deficits at first consultation, two worsened and five remained stable. Of the 41 patients without deficits, seven worsened and 34 remained stable. None of the patients developed severe motor deficits or experienced enlargement of the cavity; 7% of patients who presented with typical SC worsened compared with 35% with atypical SC. The negative predictive value was 0.93 (P = 0.02). Conclusion: Most patients remained stable and a subset of patients developed minor motor deficits. For clinical management, we propose surveillance of patients with a typical SC and close follow-up of those with an atypical SC and/or presenting with deficits.

Long-term follow-up of Chiari-related syringomyelia in adults: analysis of 157 surgically treated cases.

OBJECTIVE: To determine the long-term outcome of surgically treated Chiari-related syringomyelia. METHODS: The medical charts of 157 consecutive surgically treated patients with Chiari-related syringomyelia were retrospectively analyzed. Factors predicting outcome, either clinical or radiological, are discussed, and our results are compared with those of other large series in the literature. RESULTS: The study included 74 men and 83 women (age range, 16-75 years; mean age at surgery, 38.3 years). Pain and sensory disturbance were the most frequent initial symptoms. The average duration of preoperative symptoms was 8.2 years. The follow-up period ranged from 82 to 204 months (median, 88 months). At the end of the study, 99 patients (63.06%) had improved, 48 (30.58%) had stabilized, 9 (5.73%) had worsened, and 1 (0.63%) had died during the postoperative period. Factors predicting improvement or stabilization were young age at the time of surgery and clinical signs of paroxysmal intracranial hypertension. Factors associated with a poor outcome were older age at the time of surgery, arachnoiditis, and a clinical feature of long-tract impairment syndrome. The presence of arachnoiditis or of basilar invagination was associated with poor clinical presentation (P = 0.05 and 0.0001, respectively). The extent of the cyst on postoperative magnetic resonance imaging was a predictor of poor clinical outcome (P = 0.002). CONCLUSION: Our results confirmed that surgery is an effective and safe treatment of Chiari-related syringomyelia, with a 90% chance of long-term stabilization or improvement on average. Surgery should be proposed as soon as possible in patients with clearly progressing clinical features.