Intradiploic encephalocele of the primary motor cortex in an adult patient: electrophysiological implications during surgery

Epilepsy Surgery Outcome of Traumatic Intradiploic Meningoencephalocele: A Case Report and Literature Review

We highlight an under-recognized epileptic pathology in a 56-year-old left-handed female with progressive right facial numbness and weekly focal seizures characterized by episodic aphasia. She was found to have a left frontoparietal intradiploic meningoencephalocele (IDME). Her only epilepsy risk factor was minor head trauma 10 years prior to presentation. She underwent craniotomy for encephalocele resection and mesh cranioplasty without residual neurological deficits and excellent seizure outcome: at 3-year follow-up, she was still seizure-free since surgery, except for an isolated breakthrough seizure at 7 postoperative months when she discontinued her preoperative regimen of Lacosamide monotherapy. Traumatic IDME is a rare condition and rarely presents with seizures. Symptoms may arise up to decades following minor head trauma and are progressive in nature. The likely definitive treatment is cranioplasty and dural repair with or without resecting the protruding parenchyma.

Frontal intradiploic encephalocele in a 44-year-old male patient: illustrative case

BACKGROUND

Encephaloceles are protrusions of the cerebral tissue through a skull defect. They occur mostly in children and very rarely in adults.

OBSERVATIONS

The authors present a case of a 44-year-old man presenting with a first-time generalized seizure. Computed tomography of the head showed bone destruction associated with a right frontal lesion. Magnetic resonance imaging scans demonstrated a largely isointense lesion in the intradiploic space that contained small, hyperintense nodular components and showed a low to moderate contrast agent enhancement.

LESSONS

The patient underwent resection, during which the histological examination found the lesion to be an intradiploic encephalocele. The patient had an uneventful postoperative course with a cessation of seizures. The imaging and neuropathological findings as well as a literature review, together with a discussion on the etiology of intradiploic encephaloceles, are contained in this report.

A red herring CVA with unexpected outcome: illustrative case

BACKGROUND

Disruptions to the integrity of the inner table and trabeculae of the calvaria are rare phenomena. Increasingly rare is the phenomenon of herniation of brain parenchyma through the defects in the skull causing neurological deficit. Surgical intervention is commonly performed but is fraught with risk of brain tissue loss.

OBSERVATIONS

The authors present a case of a 78-year-old White male presenting with strokelike symptoms who was found to have an intradiploic encephalocele that was successfully treated with surgical intervention and neuroplastic reconstruction of the anatomical deficit. The patient had a marked recovery and had near-complete resolution of symptoms.

LESSONS

This notably rare phenomenon resolved with neurosurgical intervention, sparing the parenchyma, and provided the patient with perceivably normal contour of the head using a collaborative approach with neuroplastic intervention.

Brain herniation (encephalocele) into arachnoid granulations: prevalence and association with pulsatile tinnitus and idiopathic intracranial hypertension

PURPOSE

Brain herniation into arachnoid granulations (BHAG) of the dural venous sinuses is a recently described finding of uncertain etiology. The purpose of this study was to investigate the prevalence of BHAG in a cohort of patients with pulsatile tinnitus (PT) and to clarify the physiologic and clinical implications of these lesions.

METHODS

The imaging and charts of consecutive PT patients were retrospectively reviewed. All patients were examined with MRI including pre- and post-contrast T1- and T2-weighted sequences. Images were reviewed separately by three blinded neuroradiologists to identify the presence of BHAG. Their location, signal intensity, size, presence of arachnoid granulation, and associated dural venous sinus stenosis were documented. Clinical records were further reviewed for idiopathic intracranial hypertension, history of prior lumbar puncture, and opening pressure.

RESULTS

Two hundred sixty-two consecutive PT patients over a 4-year period met inclusion criteria. PT patients with BHAG were significantly more likely to have idiopathic intracranial hypertension than PT patients without BHAG (OR 4.2, CI 1.5-12, p = 0.006). Sixteen out of 262 (6%) patients were found to have 18 BHAG. Eleven out of 16 (69%) patients had unilateral temporal or occipital lobe herniations located in the transverse sinus or the transverse-sigmoid junction. Three out of 16 (19%) patients had unilateral cerebellar herniations and 2/16 (13%) patients had bilateral BHAG.

CONCLUSION

In patients with PT, BHAG is a prevalent MRI finding that is strongly associated with the clinical diagnosis of IIH. The pathogenesis of BHAG remains uncertain, but recognition should prompt comprehensive evaluation for IIH.

Intradiploic Encephalocele at the Parietal Bone: A Case Report and Literature Review

Intradiploic encephalocele is a rare condition of herniation of the brain parenchyma through the diploic space. A 52-year-old man presented with a parietal intradiploic encephalocele manifesting as an intermittent headache for 7 months. CT revealed an osteolytic lesion involving the right parietal bone. MRI demonstrated brain herniation within the diploic space. Surgery may be unnecessary in the absence of concurrent symptoms or neurological deficits. After 2 years of follow-up, symptoms were improved without neurological deficits and CT findings. We report the X-ray, CT, and MRI findings of an extremely rare case of parietal intradiploic encephalocele in adulthood.

Intradiploic encephalocele following linear skull fracture: a rare evolution of growing skull fracture

Growing skull fracture (GSF) is a rare complication of pediatric head trauma. It usually arises from a linear fracture with an underlying dural tear, which results in herniation of the intracranial contents. In rare cases, the herniated intracranial contents can be restricted in the diploe, resulting in an expanded diploic cavity. If there is brain parenchyma herniating into the expanded diploic cavity, the condition is termed as intradiploic encephalocele (IE). Here we present a peculiar pediatric occipital GSF case that resulted from the silent progression of a linear fracture with a small brain herniation into the widened fracture finally leading to an IE after approximately 7 years. Detailed imaging findings from the early injury to the late phase of the disease were provided to record this natural process. To the best of our knowledge, this is the first case providing the imaging data of early injury before developing into IE.

Motor Evoked Potential Warning Criteria in Supratentorial Surgery: A Scoping Review

During intraoperative monitoring of motor evoked potentials (MEP), heterogeneity across studies in terms of study populations, intraoperative settings, applied warning criteria, and outcome reporting exists. A scoping review of MEP warning criteria in supratentorial surgery was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Sixty-eight studies fulfilled the eligibility criteria. The most commonly used alarm criteria were MEP signal loss, which was always a major warning sign, followed by amplitude reduction and threshold elevation. Irreversible MEP alterations were associated with a higher number of transient and persisting motor deficits compared with the reversible changes. In almost all studies, specificity and Negative Predictive Value (NPV) were high, while in most of them, sensitivity and Positive Predictive Value (PPV) were rather low or modest. Thus, the absence of an irreversible alteration may reassure the neurosurgeon that the patient will not suffer a motor deficit in the short-term and long-term follow-up. Further, MEPs perform well as surrogate markers, and reversible MEP deteriorations after successful intervention indicate motor function preservation postoperatively. However, in future studies, a consensus regarding the definitions of MEP alteration, critical duration of alterations, and outcome reporting should be determined.

Tissue damage in herniated brain parenchyma into giant arachnoid granulations: demonstration with high resolution MRI

BACKGROUND

Brain herniation (BH) into arachnoid granulation has been remarkable in recent years.

PURPOSE

To evaluate the damage in herniated parenchyma into the giant arachnoid granulation (GAG) and to investigate the clinical-demographic importance of this damage.

MATERIAL AND METHODS

Patients with BH into GAG were retrospectively included in the study. Each of the patients had at least one high-resolution 3D magnetic resonance imaging (MRI) sequence. The arachnoid granulation dimensions, locations, and origin of herniated parenchyma were evaluated by two experienced radiologists. The demographic and symptomatic features of the patients were recorded from the hospital database.

RESULTS

A total of 27 patients (21 females, 6 males; age range 6-71 years; mean age 41.3 years) were found to contain BH into GAG. It was most commonly seen in the transverse sinus (67%); the origin was most common in the cerebellar parenchyma (56%). Abnormal signal and morphology were detected in herniated parenchyma in 11 (47%) patients, atrophy in six, and atrophy and gliosis in five. The most common complaints were headache (47%), while other frequent symptoms were vertigo (15%) and blurred vision (11%). There was a statistically significant positive correlation between frequency of damage in herniated brain parenchyma and the maximal size of GAG (P<0.05).

CONCLUSION

In patients with BH into GAG, parenchymal damage may be associated with various symptoms, such as headache and vertigo, although they have not been statistically proven. It is important to carefully evaluate hernia tissue, as the risk of tissue damage may increase in larger GAGs.

Transcranial cerebellar herniation following craniotomy: Case report and literature review

To report a case of post-surgical encephalocele through craniotomy burr holes following the resection of a meningioma of the posterior fossa. A 49-year-old female presented in the emergency room with cephalea. The MRI showed a meningioma of the convexity of the posterior fossa. A resection was performed and the bone flap replaced. The patient recovered uneventfully and was discharged. After 30 days the patient consulted referring cephalea, vomiting and imbalance. Brain MRI revealed a trans-cranial cerebellar herniation through the craniotomy burr holes. An urgent surgery was performed to repair the encephalocele. Post-surgical brain MRI was performed and did not show complications. Post-surgical encephalocele is an uncommon complication after the resection of a posterior fossa lesion. To avoid this complication, it is recommended thorough dural and bony closure, particularly in the posterior fossa surgeries and in high-risk patients.