Complication Avoidance in Chiari Malformation Surgery.

Surgery for symptomatic Chiari type I malformation (CM-I) patients include posterior fossa decompression (PFD) involving craniectomy with or without dural opening, and posterior fossa decompression with duraplasty (PFDD). This review aims to examine the evidence to aid surgical decision-making. A medical database search was expanded to include article references to identify all relevant published case series. Animal studies, editorials, letters, and review articles were excluded. A systemic review and meta-analysis were performed to assess clinical and radiological improvement, complications, and reoperation rates. Seventeen articles, containing data on 3618 paediatric and adult participants, met the inclusion criteria. In the group, 5 papers included patients that had the dura left open. PFDD is associated with better clinical outcomes (RR 1.24, 95% CI, 1.07 to 1.44; P = 0.004), but has a higher complication rate (RR 4.51, 95% CI, 2.01 to 10.11; P = 0.0003). In adults, clinical outcomes differences did not reach statistical significance (P = 0.07) but re-operation rates were higher with PFD (RR 0.17, 95% CI 0.03 to 0.86; P = 0.03), whilst in children re-operation rates were no different (RR 0.97, 95% CI 0.41 to 2.30; P = 0.94). Patients with a syrinx did better with PFDD (P = 0.02). No significant differences were observed concerning radiological improvement. In the absence of hydrocephalus and craniocervical region instability, PFDD provides better clinical outcomes but with higher risk. The use of PFD may be justified in some cases in children, and in the absence of a syrinx. To help with future outcome assessments in patients with a CM-I, standardization of clinical and radiological grading systems are required. not required.

Chiari malformation, a condition that disrupts cerebrospinal fluid circulation. While previous studies have extensively explored the symptoms, treatment approaches, and clinical outcomes for patients with Chiari malformation accompanied by syringomyelia, there is limited research focused on those without syringomyelia. This study aims to evaluate the symptoms, treatments, intradural findings, and clinical outcomes in patients with Chiari malformation without syringomyelia. This single-center, retrospective study analyzed 148 patients diagnosed with Chiari malformation without syringomyelia between January 2010 and September 2022. Patients underwent one of two surgical approaches: posterior fossa decompression (PFD) or posterior fossa decompression with duraplasty (PFDD). Data on clinical symptoms, intradural findings, surgical outcomes, and postoperative complications were collected and analyzed. A total of 148 patients were included in the study, with 30 undergoing PFD and 118 receiving PFDD. Patients treated with PFDD showed significantly improved CCOS scores compared to those treated with PFD (12.8 ± 1.9 vs. 11.8 ± 2.5, P = 0.018). Symptom improvement rates were comparable between the two groups. Among PFDD patients, over 80% exhibited intradural abnormalities, with 28.4% classified as severe. Severe intradural abnormalities were strongly associated with higher rates of Valsalva-provoked pain (59.5% vs. 26.3%, P < 0.001). PFDD significantly improves CCOS scores compared to PFD, highlighting its potential as a more effective surgical approach for Chiari malformation without syringomyelia. Clinical trial number Not applicable.

Excess flexion or extension during occipitocervical fusion (OCF) can lead to postoperative complications, such as dysphagia, respiratory problems, line of sight issues, and neck pain, but posterior fossa decompression (PFD) and OCF require different positions that require intraoperative manipulation. The objective of this study was to describe quantitative fluoroscopic morphometrics in Chiari malformation (CM) patients with symptoms of craniocervical instability (CCI) and demonstrate the intraoperative application of these measurements to achieve neutral craniocervical alignment while leveraging a single axis of motion with the Mayfield head clamp locking mechanism. A retrospective cohort study of patients with CM 1 and 1.5 and features of CCI who underwent PFD and OCF at a single-center institution from March 2015 to October 2020 was performed. Patient demographics, preoperative presentation, radiographic morphometrics, operative details, complications, and clinical outcomes were analyzed. A total of 39 patients met the inclusion criteria, of which 37 patients (94.9%) did not require additional revision surgery after PFD and OCF. In this nonrevision cohort, preoperative to postoperative occipital to C2 angle (O-C2a) (13.5° ± 10.4° vs. 17.5° ± 10.1°, P = 0.047) and narrowest oropharyngeal airway space (nPAS) (10.9 ± 3.4 mm vs. 13.1 ± 4.8 mm, P = 0.007) increased significantly. These measurements were decreased in the two patients who required revision surgery due to postoperative dysphagia (mean difference - 16.6°° in O C2a and 12.8°° in occipital and external acoustic meatus to axis angle). Based on these results, these fluoroscopic morphometrics are intraoperatively assessed, utilizing a locking Mayfield head clamp repositioning maneuver to optimize craniocervical alignment prior to rod placement from the occipital plate to cervical screws. Establishing a preoperative baseline of reliable fluoroscopic morphometrics can guide surgeons intraoperatively in appropriate patient realignment during combined PFD and OCF, and may prevent postoperative complications.

This study investigated whether the selection of different dural substitutes and distinct dural repair techniques correlates with the incidence rate of postoperative CSF leak in a mixed population of adults and children with Chiari type I malformation (CM-I) who underwent posterior fossa decompression with enlargement duraplasty (PFDD) as the first surgical approach. A retrospective analysis was conducted on all patients admitted to the authors' institution between 2006 and 2023 for PFDD to treat syringomyelia and/or symptoms due to CM-I. Clinical, radiological, and surgical data were extracted from a prospectively maintained database. Demographic information was collected from medical records. Surgical procedures were also scrutinized, specifically focusing on the type of dural graft used for duraplasty, alongside perioperative complications and the necessity for subsequent surgeries. Lastly, during follow-up, the occurrence of a CSF leak was assessed and analyzed in relation to the type of dural graft used during surgery. The type of dural substitute chosen changed over the years to reduce CSF fistulas, while the technique of PFDD remained the same. Consequently, large sequential homogeneous groups differing only by dural substitutes were available for comparison. The data from 409 patients with CM-I undergoing PFDD were analyzed. A total of 368 cases had complete surgical data and were included. Thirty patients received autologous duraplasty. The remaining 338 cases with heterologous duraplasty from equine and bovine pericardium were considered for the comparative statistical analysis. The mean follow-up duration ranged from 39 months in adults to 45 months in children. The CSF complication rate requiring revision was 6.5% in the total cohort, with a higher incidence in children (10.5%) compared with adults (3.9%). There was no significant difference in adverse events (CSF leak, revision surgery, or ventriculoperitoneal shunt placement) between the different dural patches by univariate analysis if applied to the total cohort, although the trend neared significance (p = 0.06). In pediatric cases, this value was significant (p = 0.01) in favor of equine pericardium, particularly when combined with a collagen matrix inlay graft. This study on a large and homogeneous series of patients with CM-I undergoing PFDD with heterologous duraplasty demonstrated that CSF complications may be kept low. The dural substitutes derived from equine pericardium, particularly when combined with a collagen matrix inlay graft, exhibited a reduced rate of CSF leaks compared with substitutes derived from bovine pericardium.

The most appropriate surgical technique for posterior fossa decompression in Chiari malformation (CM) remains a matter of debate. Intraoperative electrophysiological studies during posterior fossa decompression of Type I CM (CM-I) aim to shed light on the entity's pathomechanism as well as on the ideal extent of decompression. The existing reports on this issue state that significant improvement in conduction occurs after craniotomy in all cases, but additional durotomy contributes a further improvement in only a minority of cases. This implies that craniotomy alone might suffice for clinical improvement without the need of duraplasty or even subarachnoid manipulation at the level of the craniocervical junction. In contrast to published data, the authors describe the case of a 32-year-old woman who underwent surgery for CM associated with extensive cervicothoracic syringomyelia and whose intraoperative somatosensory evoked potentials (SSEPs) did not notably improve after craniotomy or following durotomy; rather, they only improved after opening of the fourth ventricle and restoration of CSF flow through the foramen of Magendie. Postoperatively, the patient recovered completely from her preoperative neurological deficits. To the authors' knowledge, this is the first report of significant SSEP recovery after opening the fourth ventricle in the decompression of a CM-I. The electrophysiological and operative techniques are described in detail and the findings are discussed in the light of available literature. The authors conclude that there might be a subset of CM-I patients who require subarachnoid dissection at the level of the craniocervical junction to benefit clinically. Prospective studies with detailed electrophysiological analyses seem warranted to answer the question regarding the best surgical approach in CM-I decompression.

Posterior Fossa Decompression and Duraplasty with and without Arachnoid Preservation for the Treatment of Adult Chiari Malformation Type 1: A Systematic Review and Meta-Analysis

Objective To evaluate the revision surgical techniques with intraoperative CT navigation system for the treatment of craniocervical junction malformation after inappropriate excessive posterior fossa decompression.Methods 12 patients with Chiari Ⅰ malformation,basilar invagination and syringomyelia,after extensive posterior fossa decompression received the revision surgery from April 2009 to March 2012.The clinical presentation,treatment and follow-up results of the patients were retrospectively studied.Results The 12 patients included 5 females and 7 males.The mean age was 37.4 years.The most common symptom was motor deficit in 12 patients.Syringomyelia occurred in 8 patients.Three patients got cerebellar ptosis.8 patients were performed the posterior fixation and fusion in a reduced position with the intraoperative CT and neuronavigation.4 patients with irreducible craniovertebral junction were only performed the posterior occipitocervical fixation,whereas 1 patient was performed the posterior occipitocervical fixation,and a transoral odontoidectomy was performed as the second procedure.During 9-24 months of follow-up,solid bone fusion was observed between the occipital bone and axis in all patients.The syringomyelia in 7 patients was improved.The cerebellar ptosis of 3 patients was resolved.The range of McCormick grade was Ⅰ-Ⅲ and the range of 6 months postoperative KPS score was 80-100.Conclusions It was necessary that simultaneous fixation and fusion after an appropriate posterior decompression in patients of basilar invagination associated with Chiari malformation.The revision occipitocervical fixation and fusion with the intraoperative CT and neuronavigation for the treatment of craniocervical junction malformation after inappropriate excessive posterior fossa decompression could be successfully performed. Key words: Arnold chiari malformation type Ⅰ; Fixation; Neuronavigation; Intraoperative computed tomography

The true importance of performing a watertight dural closure, for neurological procedures, is to avoid several complications such as cerebrospinal fluid (CSF) leakage, pseudomeningocele (PSM), meningitis, cerebral abscess, tonsilar herniation, hydrocephalus, etc1 […] Cerebellum, brainstem and spinal cord adhesions following basilar impression and Chiari malformation surgery

Object A subset of patients with Chiari malformation Type I (CM-I) presented with acute onset of a neurological deficit. In this study the authors summarize their experience with these patients' clinical presentation, imaging results, timing of surgery, and outcome following decompression. Methods The authors reviewed clinical records, imaging studies, and operative notes from all patients undergoing posterior fossa decompression for CM-I at St. Louis Children's Hospital from 1990 to 2008. Of the 189 patients who underwent surgery, 6 were identified with the acute onset of a neurological deficit at presentation. Results All 6 children (age range 3–14 years, 3 boys and 3 girls) had either syringomyelia (5 patients) or T2 signal changes in the spinal cord (1 patient) and CM-I on initial MR imaging. Three patients presented after minor trauma (1 with paraparesis, 2 with sensory deficits). Three patients presented without a clear history of trauma (1 with abrupt onset of spontaneous dysphagia and ataxia, 2 with sensory deficits). Decompression was performed at a mean 7.7 ± 4.9 days after symptom onset (7.0 ± 1.6 days after neurosurgical evaluation). In 1 patient, symptoms had resolved by the time of surgery; in the remainder of the patients, clear improvements were noted within 2 weeks of surgery, with complete resolution of symptoms by 12 months postoperatively. Follow-up MR images were obtained in 4 patients, demonstrating improvement in the extent of the syrinx in each patient. Conclusions Children with CM-I and syringomyelia can develop acute spinal cord or bulbar deficits with relatively minor head or neck injuries. The prognosis for symptomatic improvement in the observed deficit is good, with each patient in our series showing resolution of deficits over time. However, based on this relatively limited experience, the authors suggest that patients who present with an acute neurological deficit and are found to have CM-I be managed with early posterior fossa decompression. Patients with CM-I and syringomyelia may be at higher risk of acute neurological deficit than those without a syrinx.

Posterior fossa decompression, with or without duraplasty, is effective for the treatment of pediatric patients with symptomatic Chiari malformation type I (CM-I). The aim of this study was to compare effectiveness and clinical outcomes of Y-shaped vs linear techniques during posterior fossa decompression with duraplasty (PFDD) for CM-I patients. Retrospective review of data for pediatric patients (≤21 years old) with CM-I and surgically managed with PFDD with or without C1 laminectomy was performed. Clinical characteristics, including presence of a syrinx and presentation, were recorded. Patients were dichotomized into 2 propensity score-matched (PSM) groups based on whether a Y-shaped or linear dural incision was used. All statistical tests were 2-tailed, and a P-value <.05 was significant. A total of 228 patients met the inclusion criteria, with 124 undergoing linear and 104 undergoing Y-shaped dural incision. After PSM, each group had 66 patients who were well-matched for age, sex, presentation, and extent of tonsillar herniation. Patients in the linear incision group had significantly lower estimated blood loss (Y-shaped: 66.5 ± 75.8 mL vs linear: 33.9 ± 18.9 mL, P < .01). Although the rate of complete symptom resolution was higher in the linear group before PSM (Y-shaped: 28.8% vs linear: 57.3%, P < .001), this difference was not significant after PSM (Y-shaped: 31.8% vs linear: 47%, P = .205). Similarly, fewer repeat decompression procedures were needed in the linear group before PSM (Y-shaped: 13.5% vs linear: 0.8%, P < .001) but not after (Y-shaped: 10.6% vs linear: 1.5%, P = .062). Linear and Y-shaped dural incisions are safe and effective for PFDD in pediatric CM-I patients. Linear incisions were associated with reduced blood loss, although neither group had a clinically significant blood loss and overall clinical outcomes were comparable after PSM. These findings can help guide surgical decision-making for CM-I. Further studies are warranted to validate these results and explore the influence of surgeon experience and preference on the associated outcomes.

Background:Decompression of Chiari malformation is a common procedure in both pediatric and adult neurosurgery. Although the necessity for some bony removal is universally accepted, other aspects of Chiari surgery are the subject of debate. The most controversial points include the optimal amount of bony removal, the use of duraplasty (and the type of material), the need for subarachnoid dissection, and the need for tonsillar shrinkage.Material and Methods:We critically reviewed the literature to elucidate the risks and benefits of different graft types and to clarify optimal treatment options therein. Based on our search results, 108 relevant articles were identified. With specific inclusion and exclusion criteria, we noted three studies that directly compared two tlpes of dural substitutes in Chiari malformation surgery.Results:Our review did not support the superiority of either autologous or nonautologous grafts when duraplasty is employed. Our institutional experience, however, dictates that when the pericranium is available and of good quality, it should be utilized for duraplasty. It is non-immunogenic, inexpensive, and capable of creating a watertight closure with the dura.Conclusions:Discrepancies between the three comparative studies analyzed are likely attributable to increases in pericranial quality and thickness with maturity. Future randomized studies with large numbers and the power to resolve differences in the relatively low rates of complications in Chiari surgery are warranted.

Comparison of Clinical and Radiographic Outcomes for Posterior Fossa Decompression with and without Duraplasty for Treatment of Pediatric Chiari I Malformation: A Prospective Study.

OBJECT Techniques for combined extradural and intradural decompression with expansile duraplasty for Chiari malformation type I (CM-I) have been well described, with various allogenic and autologous materials used for duraplasty. However, the approach and surgical technique used for duraplasty in our treatment of CM-I and developed by the senior author in the 1990s has not been described. METHODS A prospective database was initiated in March 2003 to denote the use of cervical fascia for duraplasty and incorporate an ongoing detailed record of complications during the surgical treatment of children and adults with CM-I with and without syringomyelia. A total of 389 surgeries for CM-I were performed on 379 patients from March 2003 to June 2016. A total of 123 posterior procedures were performed on 123 patients in which both a posterior fossa extradural and intradural decompression with duraplasty (extra-intradural) was performed. In this paper the authors describe the surgical technique for harvesting and using cervical fascia for duraplasty in the surgical treatment of CM-I and analyze and discuss complications from a prospective database spanning 2003-2016. RESULTS The authors found that cervical fascia can be harvested in patients of all ages (2-61 years old) without difficulty, and it provides a good substitute for dura in creating an expansile duraplasty in patients with CM-I. Cervical fascia is an elastic-like material with a consistency that allows for a strong watertight closure. Harvesting the cervical fascia graft does not require any further extension of the incision superiorly or inferiorly to obtain the graft. Complications were uncommon in this study of 123 children and adults. The risk of any type of complication (aseptic meningitis, CSF leak, pseudomeningocele, infection, development of hydrocephalus, and need for ventriculoperitoneal shunt) for the 78 patients in the pediatric age group was 0%. The risk of complication in the adult group was 6.7% (1 patient with aseptic meningitis and 2 patients with CSF leak). CONCLUSIONS Autologous cervical fascia is easy to obtain in patients of all ages and provides an effective material for duraplasty in the treatment of CM-I. Complications from the combination of both an extradural and intradural decompression with autologous cervical fascia duraplasty are uncommon.

Surgical outcomes using wide suboccipital decompression for adult Chiari I malformation with and without syringomyelia

Surgical results of arachnoid-preserving posterior fossa decompression for Chiari I malformation with associated syringomyelia