Pseudomeningocele Following Posterior Cranial Fossa Surgery Significantly Increases the Risk of Intracranial Infection: A 10-Year Retrospective Analysis.

Background: Posterior fossa craniotomy is commonly performed for various pathologies. However, intra-cranial infection following craniotomy causes morbidity. Pseudomeningocele is one of the main complications following posterior fossa operation. This study aimed to test the hypothesis that the risk of intra-cranial infection is increased in patients who undergo posterior fossa craniotomy with pseudomeningocele compared with those without pseudomeningocele. Methods: We retrospectively analyzed the data of patients undergoing posterior fossa craniotomy for the management of neurological pathologies at our institute from 2011 to 2020. A total of 308 craniotomies were included, and the primary outcome of interest was the occurrence of intra-cranial infection. Standard statistical methods were used to explore associations between several parameters, including pseudomeningocele, intra-cranial infection, and wound leak. Results: Of the 308 craniotomies, 41 (13.3%) developed intra-cranial infection and 59 (19.2%) involved pseudomeningocele. Of cases involving pseudomeningocele, 27 (45.8%) developed an intra-cranial infection compared with only 14 of 249 without pseudomeningocele (5.6%; p < 0.001). In the multi-variable analysis, pseudomeningocele was associated with intra-cranial infection (odds ratio [OR] 8.56; 95% confidence interval [CI] 3.145-23.299; p < 0.001) and wound leak (OR 91.339; 95% CI 10.437-799.364; p < 0.001). Conclusion: The findings indicate that patients undergoing posterior fossa craniotomy are at a greater risk of intra-cranial infection if there is pseudomeningocele after the operation.

Unmanageable Cerebrospinal Fluid Leakage With Eosinophilic Meningitis in a Gliadel Wafer Implant Patient.

Gliadel wafer implants (Eisai Inc., Woodcliff Lake, NJ, USA) have shown their efficacy in prolonging survival in patients with malignant gliomas. The safety of Gliadel wafers has also been reported; however, there is a certain risk of adverse events. We present a rare case of refractory cerebrospinal fluid (CSF) leakage with eosinophilic meningitis in a patient with glioblastoma who underwent tumor resection with Gliadel wafer implants. A 60-year-old man presented with a glioblastoma in the right temporal lobe. The patient underwent tumor resection with Gliadel wafer implants. During the postoperative course, the patient presented with intractable CSF leakage and the development of a pseudomeningocele. A delayed rise in blood and CSF eosinophil count (a few weeks after the primary operation) and positive drug-induced lymphocyte stimulation test (DLST) results against the Gliadel wafer led to the diagnosis of an allergic reaction to these implants. Removal of the Gliadel wafers resolved the eosinophilic reaction; however, the patient subsequently required a shunt procedure for persistent hydrocephalus. This case highlights the importance of investigating rare causes of refractory CSF leakage and hydrocephalus due to allergic reactions to Gliadel wafers. Delayed elevations of eosinophils in blood and CSF tests may lead to a diagnosis of eosinophilic meningitis. DLST against Gliadel wafers is also useful for diagnosis when it is available. To control the hydrocephalus, not only the shunt procedure but also wafer removal must be considered; however, patients with limited life expectancy are generally hesitant to undergo such additional procedures.

Pseudomeningocele Mimicking Sciatica.

We report on an elderly woman with sciatica due to disc herniation, experiencing complete pain resolution following surgery. Four weeks later, she developed refractory, excruciating pain with foot palsy, prompting a lumbar magnetic resonance imaging that revealed no recurrent disc herniation. Upon exploration, intermittent nerve entrapment through the dural tear and pseudomeningocele was identified. Following dural repair and nerve repositioning, the postoperative course and long-term outcome were uneventful.In contrast to recurrent disc herniation, sciatica resulting from nerve entrapment by a pseudomeningocele is exceedingly rare. Its differential diagnosis is crucial in cases with seemingly unspectacular magnetic resonance imaging findings, as paralysis can occur in symptomatic patients. The radiological presence of a postoperative pseudomeningocele could be overlooked, and the cause of sciatica might become apparent solely during surgical exploration.

Traumatic Brachial Plexus Root Avulsion With Pseudomeningocele: A Case Series.

Traumatic avulsion pseudomeningocele of the brachial plexus is an uncommon and challenging condition with particular diagnostic and treatment challenges. This case series intends to investigate the unusual consequences of brachial plexus damage, emphasizing the significance of surgical procedures and rehabilitation strategies. Three cases of traumatic avulsion pseudomeningocele with medical histories, imaging studies, procedures, and recovery plans were carefully examined. The rehabilitation approaches and surgical procedures are outlined in detail. Each case had its own unique set of difficulties and complications. Nerve grafting and pseudomeningocele repair surgery were performed. The outcomes were evaluated based on neurological examination, range of motion, sensory recovery, and patient reports. Only a few patients showed discernible improvements in their quality of life, motor function, and discomfort. In this case series, we highlight the people with traumatic avulsion pseudomeningocele of the brachial plexus and recount their inspiring journeys. Surgical procedures and rehabilitation approaches have produced favorable outcomes regarding recovering functionality and enhancing patients' general well-being. These results highlight the value of interdisciplinary partnerships and individualized strategies in treating this uncommon illness. Further, more profound research and long-term follow-up are required regarding the condition and optimizing the treatment methods for this challenging clinical entity.

Postoperative Cerebrospinal Fluid-Related Complications After Posterior Fossa and Posterolateral Skull Base Surgeries: Development of a Predictive Model and Clinical Risk Score.

BACKGROUND: Postoperative pseudomeningocele (PMC) and cerebrospinal fluid (CSF) leak are common complications following posterior fossa and posterolateral skull base surgeries. We sought to 1) determine the rate of CSF-related complications and 2) develop a perioperative model and risk score to identify the highest risk patients for these events. METHODS: We performed a retrospective cohort of 450 patients undergoing posterior fossa and posterolateral skull base procedures from 2016 to 2020. Logistic regressions were performed for predictor selection for 3 prespecified models: 1) a priori variables, 2) predictors selected by large effect sizes, and 3) predictors with P ≤ 0.100 on univariable analysis. A final model was created by elimination of nonsignificant predictors, and the integer-based postoperative CSF-related complications (POCC) clinical risk score was derived. Internal validation was done using 10-fold cross-validation and bootstrapping with uniform shrinkage. RESULTS: A total of 115 patients (25.6%) developed PMC and/or CSF leakage. Age >55 years (odds ratio [OR], 0.560; 95% confidence interval [CI], 0.328-0.954), body mass index >30 kg/m2 (OR, 1.88; 95% CI, 1.14-3.10), and postoperative CSF diversion (OR, 2.85; 95% CI, 1.64-5.00) were associated with CSF leak and PMC. Model 2 was the most predictive (cross-validated area under the receiver operating characteristic curve, 0.690). The final risk score was devised using age, body mass index class, dural repair technique, use of bone substitute, and duration of postoperative CSF diversion. The POCC score performed well (cross-validated area under the receiver operating characteristic curve, 0.761) and was highly specific (96.1%). CONCLUSIONS: We created the first generalizable and predictive risk score to identify patients at risk of CSF-related complications. The POCC score could improve surveillance, inform doctor-patient discussions regarding the risks of surgery, and assist in perioperative management.

Direct pseudomeningocele contrast injection for spinal CSF leak localization.

CT myelography has been traditionally used to evaluate post-operative paraspinal fluid collections to discern CSF leaking into a pseudomeningocele versus a contained seroma. Rather than performing a lumbar puncture and injecting intrathecal contrast for myelography, we present the first report of direct contrast injection into a post-operative paraspinal pseudomeningocele for CSF leak confirmation and localization. This is a simple procedure that has several advantages over a conventional CT myelogram for the evaluation of post-operative paraspinal fluid collections.

Intraoperative application of triamcinolone - a risk factor for delayed CSF fistula formation?

PURPOSE: Cerebrospinal fluid (CSF) leaks are a well-known complication in spinal surgery, caused mostly by incidental durotomy (ID). However, delayed pseudomeningocele formation has been described in patients following an unremarkable surgery - without ID. Intraoperative and epidural triamcinolone application has been suspected to be a potential risk factor. This study was conducted to evaluate the management of ID and identify further risk factors for secondary CSF fistula formation. METHODS: After obtaining approval from the institutional ethics committee, a total of about 5512 patients, who underwent spine surgery between January 2014 and December 2017, were retrospectively reviewed. Of those, 139 cases with intraoperative ID and 15 with delayed pseudomeningocele formation were extracted and analyzed to identify potential risk factors for a late presenting dural injury (LPDI). RESULTS: The incidence of delayed CSF fistulas was 0.27%, with 15 patients presenting with a secondary symptomatic CSF fistula following an unremarkable surgery. Triamcinolone was identified as a risk factor (p<0.001) for pseudomeningocele formation with an OR of 11.5, as it was applied in 80.0% (n=12) of these cases. Revision surgery was performed at a mean period of 6 weeks after initial surgery. CONCLUSION: In our retrospective analysis, intraoperative application of triamcinolone was significantly associated with a high rate of delayed CSF fistulas. It should therefore be used with caution and only after weighing in potential negative side effects.

Arachnoid Welding-A Simple and Economical Method of Arachnoid Closure to Prevent Cerebrospinal Fluid Leak.

BACKGROUND: Collection of cerebrospinal fluid (CSF) in the subdural compartment is a major cause of postoperative morbidity, especially for posterior fossa surgeries. Arachnoid closure techniques, including suturing of the arachnoid and use of synthetic sealants, have been described in the literature. However, they are not always feasible or effective and have not been universally adopted. METHODS: We describe the technique of arachnoid welding for a case of brainstem cavernoma. This is a simple, cost-effective, and easily reproducible technique using readily available bipolar cautery kept at a low-current setting. At the end of surgery, the arachnoid leaflets are closely approximated, and bipolar cautery is used to seal the edges together. An illustrative video shows the technical nuances of this procedure. This technique can also be applied for arachnoid closure at other cranial and spinal sites. RESULTS: Arachnoid closure can act as an effective natural barrier to keep CSF in its physiological subarachnoid compartment. It provides an additional barrier to prevent CSF leak. It also prevents morbidity associated with adhesions and arachnoiditis. Proper closure of arachnoid makes durotomy during repeat surgery much easier and avoids injury to the underlying pia. A brief review of related literature shows the benefits of closing the arachnoid before dural closure and the different techniques that have been described so far. CONCLUSIONS: The arachnoid welding technique has a wide application, is easy to learn, and can be used especially for posterior fossa surgeries in which rates of CSF leak are the highest.

Surgical management of an ossified giant lumbar pseudomeningocele: A case report.

Background: Pseudomeningoceles (PMs) are infrequent complications of spine surgery resulting from incidental durotomy and subsequent extravasation of cerebrospinal fluid. Giant PMs (GPMs), defined as ≥8 cm in major diameter, are rarely reported in the literature and present a challenge due to a lack of clear guidelines for surgical management. Case Description: Here, the authors discuss the successful surgical management of a 25.3 cm lumbar GPM that became calcified 3 years following an initial T10-S2 laminectomy with instrumented fusion performed at an outside-hospital. Conclusion: This report focuses on the successful 3-year delayed surgical intervention for the management of an ossified GPM.

Spinal Cord Herniation into a Pseudomeningocele-A Delayed Presentation following a Traumatic Cervical Root Avulsion Injury.

Background Spinal cord herniation into a traumatic pseudomeningocele is a rare clinical entity. We present the sixth known case and describe surgical management. Case Presentation A 44-year-old male presented with Brown-Sequard syndrome three decades after a cervical nerve root avulsion injury. Imaging revealed hemicord herniation into a C7/T1 pseudomeningocele in addition to extra-axial cord compression from further pseudomeningoceles. Significant clinical improvement was achieved following surgical repair. The radiological findings and technique for operative repair are described. Conclusion The case highlights this rare pathology and presentation, describes the surgical measures for repair of cord herniation, and provides evidence for the favorable outcome that can be achieved by surgical intervention.

Rates of cerebrospinal fluid leak and pseudomeningocele formation after posterior fossa craniotomy versus craniectomy: A systematic review and meta-analysis.

Background: Postoperative cerebrospinal fluid (CSF) leak is a major concern after posterior fossa surgery with significant clinical implications. It has been postulated that replacing the bone flap, performing a craniotomy, would reinforce the surgical closure and decrease rates of CSF leak. This systematic review and meta-analysis compared the rate of CSF leak after posterior fossa craniotomies versus craniectomies. Methods: Three databases were searched for English studies comparing the primary outcome, rate of CSF leak, after adult posterior fossa craniotomies versus craniectomies. Secondary outcomes included the rate of postoperative pseudomeningocele formation, CSF leak and pseudomeningocele formation, CSF diversion, revision surgery, and infection. Pooled estimates and relative risks for dichotomous outcomes were calculated using Review Manager 5.4, with corresponding 95% confidence intervals (CIs). Results: A total of 1250 patients (635 craniotomies and 615 craniectomies), from nine studies, were included in the final analysis. Even though rates of CSF leak favored craniotomies, the difference did not reach statistical significance in our pooled analysis (Risk Ratio: 0.71, 95% Confidence Interval: 0.45-1.14, p-value = 0.15, Heterogeneity I-squared = 0%). On the other hand, comparing the rates of pseudomeningocele formation and CSF leak, as a combined outcome, or pseudomeningocele formation only showed a significant difference favoring craniotomies. The quality of evidence in this meta-analysis was graded as having a high risk of bias based on the risk of bias in non-randomized studies - of exposure criteria. Conclusion: Based on evidence with high risk of bias, rates of postoperative CSF leak and pseudomeningocele formation favored posterior fossa craniotomies over craniectomies. Further research with more robust methodology is required to validate these findings.

Post-Operative Complications after Foramen Magnum Decompression with Duraplasty Using Different Graft Materials in Adults Patients with Chiari I Malformation: A Systematic Review and Meta-Analysis.

Despite extensive investigations, the choice of graft material for reconstructive duraplasty after foramen magnum decompression for Chiari type I malformation (CMI) is still a topic of discussion. The authors performed a systematic review and meta-analysis of the literature examining the post-operative complications in adult patients with CMI after foramen magnum decompression and duraplasty (FMDD) using different graft materials. Our systematic review included 23 studies with a total of 1563 patients with CMI who underwent FMDD with different dural substitutes. The most common complications were pseudomeningocele (2.7%, 95% CI 1.5-3.9%, p < 0.01, I2 = 69%) and CSF leak (2%, 95% CI 1-2.9%, p < 0,01, I2 = 43%). The revision surgery rate was 3% (95% CI 1.8-4.2%, p < 0.01, I2 = 54%). A lower rate of pseudomeningocele was observed with autologous duraplasty when compared with synthetic duraplasty (0.7% [95% CI 0-1.3%] vs. 5.3% [95% CI 2.1-8.4%] p < 0.01). The rate of CSF leak and revision surgery was lower after autologous duraplasty than after non-autologous dural graft (1.8% [95% CI 0.5-3.1%] vs. 5.3% [95% CI 1.6-9%], p < 0.01 and 0.8% [95% CI 0.1-1.6%] vs. 4.9% [95% CI 2.6-7.2%] p < 0.01, respectively). Autologous duraplasty is associated with a lower rate of post-operative pseudomeningocele and reoperation. This information should be considered when planning duraplasty after foramen magnum decompression in patients with CMI.

Lumbar Laminectomy Precedes Positional Headache and MRI-Confirmed Pseudomeningocele With Duro-Cutaneous Fistula.

Pseudomeningoceles (PMs) are collections of cerebrospinal fluid (CSF) occurring as a direct result of a dural rent. This article presents a well-documented case of a 68-year-old male presenting to the emergency department with postoperative lumbar PM with a duro-cutaneous fistula. It was initially recognized on palpation of the patient's postoperative incision site and later diagnosed with magnetic resonance imaging (MRI). Incidental durotomies (IDs) leading to PMs are a rare complication of laminectomies and other spinal surgeries. A thorough physical exam, diagnostic imaging, and lumbar drainage to survey the integrity of the dura mater are important aspects of postoperative care.

Abducens nerve palsy associated with pseudomeningocele after cervical spine surgery: a case report.

Background: Cerebrospinal fluid leakage can cause abducens nerve palsy (ANP) secondary to downward brain traction, caused by intracranial hypotension. We present the first case after cervical fixation and fusion with spinal cord decompression. Case Description: We present a 65-year-old male, who undergone C5-C6 decompression by laminectomy and C3-T2 fixation and fusion, without intraoperative complications. Two months later, the patient referred a 2-week history of diplopia, with no other accompanying symptom. Clinical examination revealed a lack of lateral gaze of the left eye. Cervical MRI disclosed findings compatible with pseudomeningocele. Given the time of evolution, the subacute clinical findings and the absence of image or clinical data of infection or intracranial hypotension, we decided to perform conservative treatment. We submitted the patient to periodic clinical examinations and we confirmed progressive clinical improvement of diplopia, in association with neurologic and ophthalmologic specialists. At this time, six months after surgery, the patient is asymptomatic. The swelling has significantly decreased in size. Control MRI revealed no growth of the pseudomeningocele. Conclusions: ANP secondary to intracranial hypotension after cervical spine surgery requires immediate imaging tests and clinical evaluation from neurology and ophthalmology specialists. Management can be conservative, as long as diplopia is the only clinical and radiological finding and wound does not show signs of infection.

The Management of Recurrent Post-myelography Lumbar Pseudomeningocele With Epidural Blood Patch.

Pseudomeningoceles are a well-known potential postoperative complication of spinal and cranial surgeries that can occur after lumbar decompression and posterior fossa surgeries. They are often caused by incidental durotomies but may also occur as a result of dural puncture during diagnostic testing. This report describes a 59-year-old male that developed a recurrent pseudomeningocele after an L4 laminectomy for severe lumbar spinal stenosis that was ultimately treated with an epidural blood patch (EBP). His preoperative condition greatly improved, but he developed a pseudomeningocele that did not resolve after applying ice and light pressure. The patient subsequently underwent a wound exploration where no dural defect was identified. During this exploration, the dura was reinforced with dural onlays and sealant. Unfortunately, the patient developed another pseudomeningocele within a short interval. It was then suspected that the post-laminectomy site provided a space for the dural punctures from previous CT myelography to leak cerebrospinal fluid (CSF) into. The patient subsequently underwent ultrasound (US)-guided aspiration of the pseudomeningocele and EBP injections at the levels where his preoperative myelography was performed. The success of the EBP indicates that the previous CT myelography was the likely cause of the pseudomeningocele. Recurrent spinal pseudomeningoceles with no evidence of incidental durotomy may be caused by dural puncture from myelography. In such cases, EBP to the area that the previous myelography was performed can resolve the pseudomeningocele.

Successful Management of Iatrogenic Cranial Pseudomeningocele With Subgaleal Shunt.

Iatrogenic pseudomeningocele is a common complication of cranial surgeries. However, there are no evidence-based guidelines on how to manage this condition. We report two cases of iatrogenic postoperative cranial pseudomeningocele that failed conservative management including compressive head dressing. Subgaleal shunt placement was utilized with successful resolution in both cases. We postulate that subgaleal shunt placement may be an effective method in the management of iatrogenic subgaleal pseudomeningocele.

Incidence and management of postoperative pseudomeningocele and cerebrospinal fluid leak after Chiari malformation type I decompression.

OBJECTIVE: The optimal surgical management of Chiari malformation type I (CM-I) remains controversial and heterogeneous. The authors sought to investigate patient-specific, technical, and perioperative features that may affect the incidence of CSF-related complications including pseudomeningocele and CSF leak at their institution. METHODS: The authors performed a single-center, retrospective review of all adult patients with CM-I who underwent posterior fossa decompression. Patient demographics, operative details, and perioperative factors were collected via electronic medical record review. The authors performed Fisher's exact test and independent Student t-tests for categorical and continuous variables, respectively. Univariate regression analysis was performed to determine odds ratios. A multivariable regression analysis was performed for those factors with p < 0.10 or large effect sizes (OR ≥ 2.0 or ≤ 0.50) by univariate analysis. The STROBE guidelines for observational studies were followed. RESULTS: A total of 59 adult patients were included. Most patients were female (78.0%), and the mean body mass index was 32.2 (± 9.0). Almost one-third (30.5%) of patients had a syrinx on preoperative imaging. All patients underwent expansile duraplasty, of which 47 (79.7%) were from autologous pericranium. Arachnoid opening for fourth ventricular inspection was performed in 26 (44.1%) cases. CSF-related complications were identified in 18 (30.5%) of cases. Thirteen (22.0%) patients required readmission and 11 (18.6%) required intervention such as wound revision (n = 5), wound revision with CSF diversion (n = 4), CSF diversion alone (n = 1), or blood patch (n = 1). Three (5.1%) patients required permanent CSF diversion. Male sex (OR 3.495), diabetes mellitus (OR 0.249), tobacco use (OR 2.53), body mass index more than 30 (OR 2.45), preoperative syrinx (OR 1.733), autologous duraplasty (OR 0.331), and postoperative steroids (OR 2.825) were included in the multivariable analysis. No factors achieved significance by univariate or multivariable analysis (all p > 0.05). CONCLUSIONS: The authors report a single-center, retrospective experience of posterior fossa decompression for 59 adults with CM-I. No perioperative or technical features were found to affect the CSF-related complication rate. More standardized practices within centers are necessary to better delineate the true risk factors and potential protective factors against CSF-related complications.

Safety and effectiveness of spinal dural defect repair in the management of superficial siderosis: A systematic review and patient-level analysis.

OBJECTIVE: Superficial siderosis (SS) is a disabling neurodegenerative condition that may be caused by spinal dural defects. Surgical repair is increasingly performed, however clinical outcomes remain unclear. METHODS: A systematic search of PubMed, MEDLINE, and EMBASE was conducted (inception to February 2020). Studies reporting cases of (i) superficial siderosis, (ii) spinal dural defect, (iii) and surgical closure of the defect were included. Demographic characteristics, clinical presentation, operative technique and clinical outcome were extracted for patient-level analysis. RESULTS: A total of 26 publications were included, which reported 38 patients with a median age of 58 years, and a male predominance (78.9 %). Ataxia (85.7 %) and hearing loss (80.0 %) were the most common presenting symptoms. The causative dural defect was most commonly ventral in location (91.7 %) and most commonly identified by CT myelography (48.6 %). Operative technique was highly variable and included primary suture, fibrin glue, dural substitute, or tissue (fat or muscle) graft. Clinical improvement was reported in 21 %, with stabilisation of symptoms in the majority (66 %) and clinical deterioration in 13.2 %. Surgical complications were observed in 7.9 %. CONCLUSION: In patients with superficial siderosis and spinal dural defect, operative closure leads to improvement or stabilisation of symptoms in the vast majority (87%) of patients.

Spinal pseudomeningocele closure: capsulofascial interposition technique.

INTRODUCTION: The development of a spinal pseudomeningocele is a complication of dural repair or reconstruction that carries significant morbidity for pediatric patients. In addition to cerebrospinal fluid (CSF) hypotension and positional headaches, CSF leaking into the extradural space increases the risk for incisional breakdown, meningitis, and cosmetic deformity. Spinal pseudomeningocele management is challenging, and reported techniques range from local wound revisions/exploration to shunt placement for permanent CSF diversion. METHODS: At our institution, we have recently implemented a multidisciplinary approach of capsulofascial interposition for the surgical repair of the symptomatic spinal pseudomeningocele with a combined neurosurgery-plastic surgery team. To our knowledge, this technique has not previously been characterized, and we describe the technical aspects of this surgery here. RESULTS: Among 10 patients treated with this technique, none required reoperation or developed infections following pseudomeningocele closure; 2 patients received postoperative transfusions; and 2 patients underwent CSF diversion procedures. CONCLUSION: We propose that this capsulofascial interposition technique should be employed in the surgical treatment of symptomatic spinal pseudomeningoceles.

Rapid ossification of a giant post-operative occipital pseudomeningocele following posterior fossa surgery.

Pseudomeningocele formation following posterior fossa surgery is a well-recognised complication, occurring in up to 33% of operated cases in some series. Ossification of a cranial pseudomeningocele is, however, an exceptionally rare event with only three prior reported cases. We present the unique case of a paediatric patient who developed rapid ossification of a giant occipital pseudomeningocele following posterior fossa surgery. An 8-year-old female patient underwent a midline posterior fossa craniotomy for resection of an exophytic brainstem low-grade glioma. Post-surgery, the patient developed pan-ventricular hydrocephalus and a large occipital pseudomeningocele, which initially increased in size despite a successful endoscopic third ventriculostomy (ETV) being performed. At approximately 3 months post-surgery, reduction of the pseudomeningocele was observed with associated prominent ossification of the pseudomeningocele wall on computed tomography (CT) imaging. Surgical excision was subsequently undertaken, and intra-operatively, a large ossified pseudomeningocele was found. Follow-up MRI 1 month later demonstrated almost complete resolution of the pseudomeningocele with an associated reduction in the degree of pan-ventricular ventriculomegaly. This case highlights that ossification of even giant pseudomeningoceles can occur over a time period of just a few months and clinicians should consider ossification whenever a change in size or consistency of a post-operative pseudomeningocele is encountered.