Intraspinal cervicothoracic junction chondrosarcoma: illustrative case

BACKGROUND

Chondrosarcoma is an uncommon spinal tumor that can present as an extraskeletal mass. Rarely, these tumors present as dumbbell tumors through the neural foramina, mimicking schwannomas or neurofibromas.

OBSERVATIONS

A 46-year-old female presented with 2 years of worsening right-arm radiculopathy. Magnetic resonance imaging of the thoracic spine revealed a peripherally enhancing extramedullary mass through the right T1 foramen and compressing the spinal cord. Computed tomography showed the mass to be partially calcified. She underwent C7-T2 laminectomy and C6-T3 posterior instrumented fusion with gross-total resection of an extradural mass. Pathology revealed a grade I chondrosarcoma. Her symptoms improved postoperatively, with some residual right-arm radicular pain.

LESSONS

Intraspinal extradural dumbbell conventional chondrosarcoma is rare, with only 9 cases, including ours, reported. Patient ages range from 16 to 72 years old, and male sex is more common in these cases. The most common location is the thoracic spine, and our case is the only reported one in the cervicothoracic junction. These tumors often mimic schwannomas on imaging, but chondrosarcoma should remain in the differential diagnosis, because management of these tumors differs. Chondrosarcoma may benefit from more aggressive resection, including en bloc resection, and may require adjuvant radiotherapy.

Tandem cranial and spinal cerebrospinal fluid leaks presenting with otogenic tension pneumocephalus: illustrative case

BACKGROUND

Cranial and spinal cerebrospinal fluid (CSF) leaks are associated with opposite CSF fluid dynamics. The differing pathophysiology between spontaneous cranial and spinal CSF leaks are, therefore, mutually exclusive in theory.

OBSERVATIONS

A 66-year-old female presented with tension pneumocephalus. The patient underwent computed tomography (CT) scanning, which demonstrated left-sided tension pneumocephalus, with an expanding volume of air directly above a bony defect of the tegmen tympani and mastoideum. The patient underwent a left middle fossa craniotomy for repair of the tegmen CSF leak. In the week after discharge, she developed a recurrence of positional headaches and underwent head CT. Further magnetic resonance imaging of the brain and thoracic spine showed bilateral subdural hematomas and multiple meningeal diverticula.

LESSONS

Cranial CSF leaks are caused by intracranial hypertension and are not associated with subdural hematomas. Clinicians should maintain a high index of suspicion for intracranial hypotension due to spinal CSF leak whenever "otogenic" pneumocephalus is found. Close postoperative follow-up and clinical monitoring for symptoms of intracranial hypotension in any patients who undergo repair of a tegmen defect for otogenic pneumocephalus is recommended.

Ocular needlefish injury with cavernous sinus thrombosis and carotid-cavernous fistula: illustrative case

BACKGROUND

The Belonidae family of fish has been implicated in various penetrating injuries; to date, however, there have been limited reports of brain injury due to this species.

OBSERVATIONS

The authors present the case of a young patient who suffered an ocular penetrating injury from a needlefish with a resultant cavernous sinus thrombosis and concomitant carotid-cavernous fistula. This case highlights the interdisciplinary management of this rare condition through a strategy of anticoagulation titration to the endpoint of fistula closure.

LESSONS

Through this report the importance of a high index of suspicion for neurovascular injury and fistula formation in penetrating ocular injuries is highlighted as well as the importance of interdisciplinary management of patients with such injuries and their sequelae.

Durability of an endoscopic management strategy for recurrent choroid plexus carcinoma with a comprehensive molecular characterization: illustrative case

OBJECTIVE

Choroid plexus carcinoma (CPC) is a rare, primarily intraventricular neoplasm. Extent of resection correlates with improved outcomes but is limited due to tumor vascularity and size. Evidence on optimal surgical management and molecular drivers of recurrence remains limited. Here the authors characterize a case of multiply recurrent CPC treated with sequential endoscopic removals over 10 years and highlight its genomic properties.

OBSERVATIONS

Five years after standard treatment, a 16-year-old female presented with a distant intraventricular recurrence of CPC. Whole exome sequencing revealed NF1, PER1, and SLC12A2 mutations, FGFR3 gain, and no TP53 alterations. Repeat sequencing on recurrences 4 and 5 years later showed persistent NF1 and FGFR3 alterations. Methylation profiling was consistent with plexus tumor, subclass pediatric B. Short-term magnetic resonance imaging detected four total isolated recurrences, all treated with complete endoscopic resections at 5, 6.5, 9, and 10 years after initial diagnosis. Mean hospital stay for all recurrences was 1 day with no complications.

LESSONS

The authors describe a patient with four isolated recurrences of CPC over a decade, each treated with complete endoscopic removal, and identify unique molecular alterations that persisted without TP53 alterations. These outcomes support frequent neuroimaging to facilitate endoscopic surgical removal following early detection of CPC recurrence.

Endovascular intervention for bilateral paramedian thalamic stroke due to occlusion of the unilateral P1 segment of the posterior cerebral artery: illustrative cases

BACKGROUND

Occlusion of the unilateral P1 segment can result in bilateral paramedian thalamic infarction in patients with anatomical variants of the bilateral paramedian thalamic artery arising from a single P1 segment. Despite the life-threatening presentation of bilateral paramedian thalamic stroke, timely diagnosis is often challenging.

OBSERVATIONS

The authors herein describe 3 patients treated with endovascular intervention for occlusion of the unilateral P1 segment wherein the bilateral paramedian thalamic arteries arose. All patients were admitted to the authors' emergency department with sudden-onset coma and respiratory distress; however, initial computed tomography was unremarkable. Despite suspicion of basilar artery occlusion, vertebral and carotid angiography revealed occlusion of the unilateral P1 segment. All patients were successfully treated with endovascular intervention. Overall, 2 patients had favorable outcomes (modified Rankin scale [mRS] scores of 0 and 1), whereas in 1 patient, the mRS score reached a baseline score of 3.

LESSONS

In patients with the variant of the bilateral paramedian thalamic artery arising from a single P1 segment, occlusion of the unilateral P1 segment can be life threatening; nevertheless, timely endovascular treatment is effective. Carotid and vertebral angiography, rather than magnetic resonance or computed tomography angiography, is useful for immediate and reliable diagnosis of the relatively small vascular lesions.

Histological changes associated with laser interstitial thermal therapy for radiation necrosis: illustrative cases

BACKGROUND

Patients with lung cancer and melanoma remain the two largest groups to develop brain metastases. Immunotherapy has been approved for treatment of stage IV disease in both groups. Many of these patients are additionally treated with stereotactic radiosurgery for their brain metastases during ongoing immunotherapy. Use of immunotherapy has been reported to increase the rates of radiation necrosis (RN) after radiosurgery, causing neurological compromise due to growth of the enhancing lesion as well as worsening of associated cerebral edema.

OBSERVATIONS

Laser interstitial thermal therapy (LITT) is a surgical approach that has been shown effective in the management of RN, especially given its efficacy in early reduction of perilesional edema. However, little remains known about the pathology of the post-LITT lesions and how LITT works in this condition. Here, we present two patients who needed surgical decompression after LITT for RN. Clinical, histopathological, and imaging features of both patients are presented.

LESSONS

Criteria for selecting the best patients with RN for LITT therapy remains unclear. Given two similarly sized lesions and not too dissimilar clinical histories but with differing outcomes, further investigation is clearly needed to identify predictors of response to LITT in the setting of SRS and immunotherapy-induced RN.

Diffuse symptomatic pneumocephalus after biportal endoscopic spinal surgery: illustrative case

BACKGROUND

Percutaneous endoscopic lumbar decompression is gaining attention as a minimally invasive surgery. Here, the authors report a rare complication of pneumocephalus caused by vacuum drain after biportal endoscopic spinal surgery (BESS) for lumbar stenosis.

OBSERVATIONS

A 79-year-old woman with spinal stenosis over the L4-5 level received BESS. No visible dural tear was encountered during surgery, and a vacuum drain was placed after surgery. Approximately 150 mL of cerebrospinal fluid was drained on postoperative day 1. Simultaneously, symptoms of intracranial hypotension were noted. Brain computed tomography (CT) revealed pneumocephalus. The patient was advised to have bed rest and hydration, and her symptoms improved subsequently. Follow-up brain CT indicated the resolution of pneumocephalus.

LESSONS

Pneumocephalus after endoscopic lumbar surgery is rare. Dural tear, high rate of normal saline irrigation, and vacuum drain placement are the associated risk factors.

Endoscopic endonasal approach for simultaneously treating a pituitary adenoma coexisting with a paraclinoid aneurysm: illustrative case

BACKGROUND

There is a certain incidence of pituitary adenomas coexisting with intracranial aneurysms, but a concurrent therapeutic strategy of tumor removal and aneurysm clipping via endoscopic endonasal approach is rarely reported. The indications and limitations of endoscopic endonasal approach surgery for this type of lesions are worth discussing.

OBSERVATIONS

The case of a pituitary tumor coexisting with a paraclinoid aneurysm was reviewed. Using an endoscopic endonasal approach, the pituitary adenoma was completely excised with extrapseudocapsular separation technique, the aneurysm was clipped at the same time, and the skull base defect was reconstructed in multilayer fashion. No tumor recurrence was found, and aneurysm clipping was complete at the 6-month follow-up after surgery.

LESSONS

For patients harboring a pituitary adenoma with a selected paraclinoid aneurysm, simultaneous tumor resection and aneurysm clipping via endoscopic endonasal approach are feasible. This strategy has the advantages of saving medical resources, promoting the patient’s rapid postoperative recovery, and reducing possible antiplatelet therapy after interventional therapy. However, surgery needs to strictly follow the indications in experienced hands, and the therapeutic effect needs to be verified by more cases and longer follow-up results.

Language improvement after awake craniotomy in a 12-year-old child: illustrative case

BACKGROUND

Although the standard procedure to treat adult patients with lesions in eloquent brain areas is awake craniotomy with direct electrical stimulation, this procedure is not often used in children because of feasibility concerns. Some studies have shown that the procedure is feasible in children. They reported the postoperative language ability, which was not based on standardized language tests for children. To give an objective overview of preoperative assessment of the language ability of a child before and after this procedure, the authors described the perioperative course, including standardized language tests for children and the awake surgery setting, of a 12-year-old child undergoing awake craniotomy with brain mapping for the indication of cavernoma in the left somatosensory cortex close to the motor cortex.

OBSERVATIONS

The patient performed better on language tests after surgery, showing that his language ability improved. He also cooperated well during the entire perioperative period. His mother was present during the awake surgery, and the patient tolerated the surgery well.

LESSONS

The authors conclude that awake craniotomy is indeed feasible in a child and that it can even result in an improved postoperative language outcome. It is, however, crucial to carefully assess, inform, and monitor the child and their proxies.

Aplastic or twiglike middle cerebral artery with contralateral middle cerebral artery stenosis showing transient ischemic attack: illustrative case

BACKGROUND

Aplastic or twiglike middle cerebral artery (Ap/T-MCA) is a rare anomaly characterized by a unilateral MCA occlusion with plexiform vessels that causes hemorrhagic and (less commonly) ischemic strokes. The reasons for this are rarely discussed, and thus optimal treatment for ischemic Ap/T-MCA remains controversial. Here, the authors report a case of Ap/T-MCA with transient ischemic attacks treated by bypass surgery and discuss the mechanism of ischemic development and treatment methods.

OBSERVATIONS

A 62-year-old hypertensive man with transient, recurrent left hemiparesis visited the authors’ hospital. Magnetic resonance angiography showed proximal occlusion of the right MCA and stenosis in the left MCA. Digital subtraction angiography revealed occlusion of the right MCA and abnormal vascular networks, leading to a diagnosis of Ap/T-MCA with contralateral MCA stenosis. Antiplatelet therapy with aspirin was insufficient, and a superficial temporal artery–MCA bypass was performed. There were no ischemic or hemorrhagic events postoperatively.

LESSONS

Atherosclerosis seems to have a significant impact on the development of ischemic stroke in patients with Ap/T-MCA, and the presence of coexisting atherosclerotic stenotic vascular lesions outside the Ap/T-MCA site is substantial in its development. Bypass surgery is a promising treatment option for ischemic Ap/T-MCA.

Traumatic sacral dermoid cyst rupture with intracranial subarachnoid seeding of lipid particles: illustrative case

BACKGROUND

Intracranial deposits of fat droplets are an unusual presentation of a spinal dermoid cyst after spontaneous rupture and are even more uncommon after trauma. Here, the authors present a case with this rare clinical presentation, along with a systematic review of the literature to guide decision making in these patients.

OBSERVATIONS

A 54-year-old woman with Lynch syndrome presented with severe headache and sacrococcygeal pain after a traumatic fall. Computed tomography of the head revealed multifocal intraventricular and intracisternal fat deposits, which were confirmed by magnetic resonance imaging (MRI) of the neuroaxis; in addition, a ruptured multiloculated cyst was identified within the sacral canal with proteinaceous/hemorrhagic debris, most consistent with a sacral dermoid cyst with rupture into the cerebrospinal fluid (CSF) space. An unruptured sacral cyst was later noted on numerous previous MRI scans. In our systematic review, we identified 20 similar cases, most of which favored surgical treatment.

LESSONS

Rupture of an intraspinal dermoid cyst must be considered when intracranial fat deposits are found in the context of cauda equina syndrome, meningism, or hydrocephalus. Complete tumor removal with close postoperative follow-up is recommended to decrease the risk of complications. CSF diversion must be prioritized if life-threatening hydrocephalus is present.

Intradural lumbar radicular arteriovenous malformation mimicking perimedullary arteriovenous malformation of the conus medullaris: illustrative case

BACKGROUND

Intradural radicular arteriovenous malformation (AVM) of the cauda equina is a rare entity of spinal AVMs. Because of the specific arterial supply of the conus medullaris and cauda equina, AVMs in this area sometimes present with confusing radiological features.

OBSERVATIONS

The authors reported a rare case of intradural radicular AVM arising from the lumbar posterior root. The patient presented with urinary symptoms with multiple flow void around the conus medullaris, as shown on magnetic resonance imaging. Digital subtraction angiography demonstrated arteriovenous shunt at the left side of the conus medullaris fed by the anterior spinal artery via anastomotic channel to the posterior spinal artery and rich perimedullary drainers. There was another arteriovenous shunt at the L3 level from the left L4 radicular artery. Preoperative diagnosis was perimedullary AVM with radicular arteriovenous fistula. Direct surgery with indocyanine green angiography revealed that the actual arteriovenous shunt was located at the left L4 posterior root. The AVM was successfully treated by coagulation of feeding branches.

LESSONS

Unilateral arteriovenous shunt fed by either posterior or anterior spinal artery at the conus medullaris may include AVM of the cauda equina despite abundant perimedullary venous drainage. Careful pre- and intraoperative diagnostic imaging is necessary for appropriate treatment.

Calcified chronic subdural hematoma: illustrative case

BACKGROUND

Calcified chronic subdural hematomas (CCSDHs) are rare variants of chronic subdural hematomas (CSDHs) accounting to only 0.3–2.7% of CSDHs. Although the majority of the patients with CSDHs recover from surgery, there still is some doubt about its being applied to CCSDHs.

OBSERVATIONS

In this case report, the authors present a case of a 75-year-old male presenting with deterioration of motor function in his left limbs over the course of 18 months and acute neurological deterioration in the form of altered sensorium for 7 days. The patient experienced an episode of aspiration in the preoperative period that led to deterioration of pulmonary function in the postoperative period. A chest radiograph showed diffuse patches suggesting pulmonary compromise. Computed tomography and magnetic resonance imaging (MRI) documented a large subdural collection at the right frontal and parietal hemisphere with calcification, which was successfully and completely removed by surgery.

LESSONS

The chances of a subdural hematoma progressing to calcification is extremely rare. The presentation of this case was such that surgical intervention was the only option left for the patient. The presence of lacunar infarcts in the thalamus on MRI can also be attributed to the calcified hematoma.

Juvenile psammomatoid ossifying fibroma of the parietal bone and review of calvarial presentations: illustrative case

BACKGROUND

Juvenile psammomatoid ossifying fibroma (JPOF) is an uncommon benign fibro-osseous lesion that only rarely presents in the calvaria.

OBSERVATIONS

The authors reported a case of JPOF in the left parietal bone of a 20-year-old patient and reviewed the 27 other cases of JPOF occurring in the calvaria as reported in the literature.

LESSONS

JPOF rarely presents in the calvaria, and because diagnosis is a histopathologic one, clinicians should consider this entity when presented with a lytic, expansile mass on imaging. Little is known about the molecular mechanisms driving development of JPOF. MDM2 amplification may play a role, although this was not seen in the case presented herein.

Takotsubo cardiomyopathy following mechanical thrombectomy for acute ischemic stroke: illustrative case

BACKGROUND

Excess neurological stress by hemorrhagic stoke induces cardiomyopathy, namely takotsubo cardiomyopathy. Here, the authors report a case of takotsubo myopathy following mechanical thrombectomy for acute large vessel occlusion.

OBSERVATIONS

A 73-year-old man was emergently brought to the authors’ hospital because of left hemiparesis and consciousness disturbance. An ischemic lesion of the right cerebral hemisphere and the right internal carotid artery occlusion was revealed. Emergently, endovascular treatment was performed, and occlusion of the artery was reanalyzed. However, he suffered from hypotension with electrocardiogram abnormality. Subsequently, coronary angiography was performed, but the arteries were patent. The authors made a diagnosis of takotsubo cardiomyopathy.

LESSONS

Endovascular recanalization for large cerebral artery occlusion is so effective that it is becoming widely used. Even in the successful recanalization, we need to care for the takotsubo cardiomyopathy.

Duroplasty in iatrogenic dorsal spinal cord herniation: illustrative case

BACKGROUND

The case report detailed an unusual presentation of an iatrogenic dorsal cord herniation at the level of the thoracic cord after insertion of an epidural catheter 8 months before presentation to the neurosurgical clinic.

OBSERVATIONS

Only 13 cases of iatrogenic dorsal cord herniation, most of which occurred after spinal surgery, have been described in the literature. This was the first case of a spinal cord hernia described after the insertion of an epidural catheter. In this case study, the authors described a 38-year-old man who presented with progressive lower limb weakness, sensory deficits, perianal numbness, and urinary/fecal incontinence. He was diagnosed with a spinal cord hernia that reherniated after an initial sandwich duroplasty repair. Definitive repair was made after his re-presentation using an expansile duroplasty.

LESSONS

In patients with previous spinal instrumentation who present with neurological symptoms, spinal cord herniation should be considered a likely differential despite its rarity. In this case, a simple duroplasty was insufficient to provide full resolution of symptoms and was associated with recurrence. Perhaps a combination of graft and expansile duroplasty may be used for repair, especially when associated with a tethered cord and in the presence of significant adhesions.

Osteosarcoma of the skull base presenting as a petrocavernous pseudoaneurysm and masquerading as an intracranial abscess: illustrative case

BACKGROUND

Telangiectatic osteosarcoma (TOS) is a rare and aggressive high-grade malignant neoplasm composed of blood-filled or empty cystic spaces resembling aneurysmal bone cysts. Uncommonly, TOSs can occur in the skull base.

OBSERVATIONS

The authors present a case of a TOS that presented as a petrocavernous carotid pseudoaneurysm and then masqueraded as an intracranial abscess. The prognosis for TOSs with intracranial involvement is typically unfavorable and inversely related to the degree of intracranial involvement.

LESSONS

Skull-based malignancies should be part of the differential diagnosis for a rapidly progressing lesion. Recovery of polymicrobial organisms during endoscopic sinus surgery should prompt reconsideration of the differential diagnosis. Postinflammatory changes from endovascular coiling have been described and can confound imaging and clinical findings.

Trigeminal neuralgia induced by brainstem infarction treated with pontine descending tractotomy: illustrative case

BACKGROUND

While cases of trigeminal neuralgia induced by a brainstem infarct have been reported, the neurosurgical literature lacks clear treatment recommendations in this subpopulation.

OBSERVATIONS

The authors present the first case report of infarct-related trigeminal neuralgia treated with pontine descending tractotomy that resulted in durable pain relief after multiple failed surgical interventions, including previous microvascular decompressions and stereotactic radiosurgery. A neuronavigated pontine descending tractotomy of the spinal trigeminal tract was performed and resulted in successful pain relief for a 50-month follow-up period.

LESSONS

While many cases of ischemic brainstem lesions are caused by acute stroke, the authors assert that cerebral small vessel disease also plays a role in certain cases and that the relationship between these chronic ischemic brainstem lesions and trigeminal neuralgia is more likely to be overlooked. Furthermore, neurovascular compression may obscure the causative mechanism of infarct-related trigeminal neuralgia, leading to unsuccessful decompressive surgeries in cases in which neurovascular compression may be noncontributory to pain symptomatology. Pontine descending tractotomy may be beneficial in select patients and can be performed either alone or concurrently with microvascular decompression in cases in which the interplay between ischemic lesion and neurovascular compression in the pathophysiology of disease is not clear.

Management of brain metastasis from eccrine porocarcinoma: illustrative case

BACKGROUND

Eccrine porocarcinoma (EP) is a rare malignant skin neoplasm, and there are still many unknowns regarding its natural history and treatment. Due to its scarcity, associated brain metastasis is a far rarer condition.

OBSERVATIONS

A 71-year-old-woman with a history of EP was diagnosed with brain metastasis. In her clinical course, the patient underwent tumor removal surgery twice and Gamma Knife radiosurgery (GKRS) four times. The tumor showed a good response to radiotherapy. The histopathological findings of the brain tumor were consistent with those of the primary skin tumor.

LESSONS

There are only a few case reports referring to the detailed treatment, especially with GKRS, of brain metastasis from EP. Few reports have presented a detailed histopathological comparison between the primary skin lesion and the metastatic brain lesion. Herein, the authors have described the clinical course, histological features, and results of multidisciplinary treatment for brain metastasis of EP.

Management of giant prolactinoma causing craniocervical instability: illustrative case

BACKGROUND

Giant prolactinomas (>4 cm) are a rare entity, constituting less than 1% of all pituitary tumors. Diagnosis can usually be achieved through endocrinological analysis, but biopsy may be considered when trying to differentiate between invasive nonfunctioning pituitary adenomas and primary clival tumors such as chordomas.

OBSERVATIONS

The authors presented a rare case of a giant prolactinoma causing significant clival and occipital condyle erosion, which led to craniocervical instability. They provided a review of the multimodal management. Management involved medical therapy with dopamine agonists, and surgery was reserved for acute neural compression or dopamine agonist resistance, with the caveat that surgery was extremely unlikely to lead to normalization of serum prolactin in dopamine agonist-resistant tumors.

LESSONS

Adjunctive surgical therapy may be necessary in cases of skull base erosion, particularly when erosion or pathological fractures involve the occipital condyles. Modern posterior occipital-cervical fusion techniques have high rates of arthrodesis and can lead to symptomatic improvement. This procedure should be considered early in the multimodal approach to giant prolactinomas because of the often dramatic response to medical therapy and potential for further craniocervical instability.

The underestimated incidence of an orbital angioleiomyoma is possibly associated with an orbital cavernous hemangioma: illustrative case

BACKGROUND

Orbital angioleiomyoma is generally considered a rare tumor; approximately 40 cases have been reported. However, after their experience with 6 consecutive cases in their single institution during 3 years, the authors speculate that the incidence of orbital angioleiomyomas is possibly underestimated.

OBSERVATIONS

A 34-year-old female presented with progressive exophthalmos of 2 years' duration. Orbital computed tomography and magnetic resonance imaging revealed a well-circumscribed orbital tumor with partial and heterogeneous gadolinium enhancement. Technetium-99m red blood cell single-photon emission computed tomography showed positive perfusion in the late blood-pool phase, which was exactly consistent with the finding of a cavernous hemangioma. Under the impression of a cavernous hemangioma, the authors accessed the mass with an endoscopic endonasal approach and completely removed it without neurological deficit. Pathological examination revealed that the final diagnosis was an angioleiomyoma with positive immunostaining results for smooth muscle actin (SMA).

LESSONS

The incidence of orbital angioleiomyomas may not be very low, as these lesions have possibly been misdiagnosed as orbital cavernous hemangiomas because of their histological similarity. Preoperative presumption and differentiation from cavernous hemangiomas are very challenging because of the rarity of orbital angioleiomyoma and similar radiological findings. SMA immunostaining may be critical to differentiate orbital angioleiomyomas from cavernous hemangiomas.

Giant frontal sinus osteoma and its potential consequences: illustrative case

BACKGROUND

Osteomas of the paranasal sinuses are benign, slow-growing bone tumors that can cause a variety of clinical features depending on their size and location. Most osteomas are asymptomatic and located in the frontal sinus. In rare cases, they may grow to extend into the cranial or orbital cavities, resulting in atypical presentations. The authors presented an aggressive case of a frontoethmoidal sinus osteoma with intracranial extension of an inflammatory sinonasal polyp.

OBSERVATIONS

A 30-year-old man with a history of chronic sinusitis presented to the hospital after three episodes of loss of consciousness, chronic worsening of headache, and decreased sense of smell. Rhinoscopic examination showed mucosal polyps arising from the infundibulum and the superior meatus. Computed tomography showed a fibro-osseous mass in the left frontal sinus. Subsequent brain magnetic resonance imaging with and without contrast revealed a large, septated intracranial left frontal lesion approximately 6.5 cm in diameter that was compressing the underlying brain parenchyma.

LESSONS

Intracranial extension of frontal sinus osteomas can have dire neurological implications. Early detection of lesions obstructing the paranasal sinuses outlet could prevent intracranial extension of the disease. The surgical approach to such tumors may be endonasal, open cranial, or a combination of both.

High-resolution MRI of a peroneal intraneural ganglion cyst arising from the knee joint: illustrative case

BACKGROUND

The advancement of high-resolution imaging and increased clinical experience have led to an increased understanding of the formation and treatment of intraneural ganglion cysts. Nearly all intraneural ganglion cysts in the common peroneal nerve have been reported to arise from a joint connection to the superior tibiofibular joint. The authors have identified four cases of intraneural ganglion cysts arising from the knee joint itself; however, none of these reported cases were well described, documented, or illustrated with high-resolution imaging.

OBSERVATIONS

Here the authors present the case of an intraneural ganglion cyst arising from the knee joint and causing intermittent weakness and pain. The articular branch to the knee joint was clearly demonstrated on high-resolution magnetic resonance imaging and confirmed at surgical exploration. The patient was treated with articular branch ligation and has had complete resolution of his symptoms without recurrence of the cyst on follow-up imaging.

LESSONS

This case adds to the mounting evidence that intraneural cyst pathology is dependent on a connection to a synovial joint as stated in the unifying theory of intraneural cyst development.

Distal ventriculoperitoneal shunt catheter tightly coiled around the valve in the absence of a subgaleal cerebrospinal fluid collection: illustrative case

BACKGROUND

Among the known complications of ventriculoperitoneal (VP) shunts, subcutaneous or subgaleal migration of distal catheters is rare. Prior case reports have proposed several risk factors, including inadequate fixation of the shunt device, presence of a large subgaleal space filled with cerebrospinal fluid (CSF), and repetitive flexion/extension movement of the head producing a "windlass effect." Tight coiling of a distal catheter around the valve without a large subgaleal space has not been reported.

OBSERVATIONS

The patient was born prematurely and underwent VP shunt placement for posthemorrhagic ventricular dilatation at 3 months of age with reassuring postoperative imaging. At approximately 3 years of age, shunt radiography and head computed tomography unexpectedly showed excess tubing coiled extracranially around the shunt valve. The patient did not exhibit any clinical symptoms of shunt malfunction and underwent an uneventful revision of the VP shunt system. No CSF-filled subgaleal space was observed intraoperatively.

LESSONS

Distal catheter migration can occur without the clear presence of a subgaleal CSF collection and symptoms of acute hydrocephalus. Appropriate fixation of the shunt system using nonabsorbable stitches is recommended to prevent catheter migration caused by the windlass effect.

Spinal arthrodesis via lumbar interbody fusion without direct decompression as a treatment for recurrent radicular pain due to epidural fibrosis: patient series

BACKGROUND

Lumbar radiculopathy is the most common indication for lumbar discectomy, but residual postoperative radicular symptoms are common. Postoperative lumbar radiculopathy secondary to scar formation is notoriously difficult to manage, with the mainstay of treatment focused on nonoperative techniques. Surgical intervention for epidural fibrosis has shown unacceptably high complication rates and poor success rates.

OBSERVATIONS

Three patients underwent spinal arthrodesis without direct decompression for recurrent radiculopathy due to epidural fibrosis. Each patient previously underwent lumbar discectomy but subsequently developed recurrent radiculopathy. Imaging revealed no recurrent disc herniation, although it demonstrated extensive epidural fibrosis and scar in the region of the nerve root at the previous surgical site. Dynamic radiographs showed no instability. Two patients underwent lateral lumbar interbody fusion, and one patient underwent anterior lumbosacral interbody fusion. Each patient experienced resolution of radicular symptoms by the 1-year follow-up. Average EQ visual analog scale scores improved from 65 preoperatively to 78 postoperatively.

LESSONS

Spinal arthrodesis via lumbar interbody fusion, without direct decompression, may relieve pain in patients with recurrent radiculopathy due to epidural fibrosis, even in the absence of gross spinal instability.

Facial palsy after temporal lobectomy for epilepsy: illustrative cases

BACKGROUND

Facial palsy is a rare, unexpected complication of temporal lobectomy (TL) for intractable epilepsy. Even without direct manipulation, the facial nerve fibers may be at risk of injury during supratentorial surgery, including TL.

OBSERVATIONS

The authors presented two cases of facial palsy after unremarkable TL. In the first case, the palsy appeared in a delayed fashion and completely resolved within weeks. In the second case, facial nerve dysfunction was observed immediately after surgery, followed by progressive recovery over 2 years. The second patient had a dehiscence of the roof of the petrous bone overlying the geniculate ganglion, which put the facial nerve at risk of bipolar coagulation thermal injury.

LESSONS

Two major mechanisms could explain the loss of facial nerve function after TL: surgery-related indirect inflammation of the nerve resulting in herpesvirus reactivation and delayed dysfunction (Bell's palsy) or indirect thermal damage to the geniculate ganglion through a dehiscent petrous roof.

Anterior cervical transvertebral approach for resection of an intraspinal ventral lesion: illustrative case

BACKGROUND

The anterior cervical corpectomy and fusion approach has been reported for the removal of ventral cervical tumors. However, the normal cervical vertebral body and the adjacent intervertebral discs have to be sacrificed. In this paper, the authors describe a novel anterior cervical transvertebral approach for the resection of cervical intraspinal ventral lesions.

OBSERVATIONS

A patient presented with an anteriorly placed extramedullary cyst. An anterior cervical transvertebral open-window and close-window approach was designed and applied to resect an intraspinal ventral enterogenous cyst. With this novel technique, a square was cut through the whole vertebral body at the four sides. After the cyst resection, the bone block was restored and fixed with a titanium miniplate. The lesion was totally resected, and the compression of the spinal cord was relieved. The physiological function of the cervical spine was kept intact after the operation. There was no postsurgical complication. The cervical alignment was normal at the 1-year postoperative follow-up.

LESSONS

The anterior cervical transvertebral open-window and close-window approach was developed and confirmed to be effective for the resection of cervical intraspinal lesions. The cervical physiological structure and function can be restored with this new technique.

Lumbar facet cyst tuberculosis: a rare cause of cauda equina compression. Illustrative case

BACKGROUND

Spinal tuberculosis may present in atypical form to involve only the posterior spinal element with relative sparing of the anterior vertebral body and intervertebral disc. Recognition of this unusual pattern is important to avoid delay in diagnosis and treatment.

OBSERVATIONS

The authors report a case of a 59-year-old woman with right-sided radiculopathy and motor weakness. Her lumbosacral magnetic resonance imaging showed a large heterogeneous cyst arising from the right L4-5 facet joint. Laminectomy with excision of the cyst was performed. During surgery, the cyst contained cheese-like material that, on histopathological examination, revealed focal aggregates of tuberculous granuloma. Postoperatively, the patient recovered remarkably with no interval development of instability or any deformity.

LESSONS

Facet cyst tuberculosis is rare but should be considered in the differential diagnosis in patients coming from endemic regions. Laminectomy with excision of the cyst along with concurrent antitubercular chemotherapy is a safe and durable treatment option in this case.

Mixed germ cell tumor infiltrating the pineal gland without elevated tumor markers: illustrative case

BACKGROUND

Tumors in the pineal region consist of various histological types, and correct diagnosis from biopsy specimens is sometimes difficult. The authors report the case of a patient with a mixed germ cell tumor infiltrating into the pineal gland despite showing no elevation of tumor markers.

OBSERVATIONS

An 18-year-old man complained of headache and nausea and showed disturbance of consciousness. Magnetic resonance imaging showed hydrocephalus associated with a cystic pineal tumor. The patient underwent tumor biopsy followed by endoscopic third ventriculostomy for hydrocephalus in a local hospital. A pineocytoma was diagnosed, and the patient was referred to the authors' hospital for treatment. Concentrations of placental alkaline phosphatase, alpha-fetoprotein (AFP), and beta-human chorionic gonadotropin in cerebrospinal fluid were not elevated. However, the authors' review of the tumor specimen revealed some immature cells infiltrating the pineal gland. These cells were positive for AFP, Sal-like protein 4, and octamer-binding transcription factor 3/4; and the diagnosis was changed to mixed germ cell tumor. Chemoradiotherapy was initiated, followed by surgical removal of the residual tumor.

LESSONS

Careful examination of all tumor specimens and immunohistochemical analyses are important for accurate diagnosis of pineal tumors.

Adult isocitrate dehydrogenase-mutant brainstem glioma: illustrative case

BACKGROUND

Adult brainstem gliomas are rare entities that demonstrate heterogeneous biology and appear to be distinct from both their pediatric counterparts and adult supratentorial gliomas. Although the role of histone 3 mutations is being increasingly understood in this disease, the effect of isocitrate dehydrogenase (IDH) mutations remains unclear, largely because of limited data.

OBSERVATIONS

The authors present the case of a 29-year-old male with an IDH1-mutant, World Health Organization grade III anaplastic astrocytoma in the dorsal medulla, and they provide a review of the available literature on adult IDH-mutant brainstem glioma. The authors have amassed a cohort of 15 such patients, 7 of whom have survival data available. Median survival is 56 months in this small cohort, which is similar to that for IDH wild-type adult brainstem gliomas.

LESSONS

The authors' work reenforces previous literature suggesting that the role of IDH mutation in glioma differs between brainstem and supratentorial lesions. Therefore, the authors advocate that adult brainstem gliomas be studied in terms of major molecular subgroups (including IDH mutant) because these gliomas may exhibit fundamental differences from each other, from pediatric brainstem gliomas, and from adult supratentorial gliomas.

Rubinstein-Taybi syndrome with scoliosis treated with single-stage posterior spinal fusion: illustrative case

BACKGROUND

Rubinstein-Taybi syndrome (RTS) is a rare disorder with a range of congenital anomalies. Although 40% to 60% of patients with RTS have scoliotic deformities, few reports discuss the outcomes of correctional surgery and postoperative care. To raise awareness of the clinical features of RTS and surgical considerations, the authors report on the surgical treatment of a pediatric patient with RTS accompanied by scoliosis.

OBSERVATIONS

A 14-year-old girl with RTS presented with low back pain associated with progressive scoliosis. Because of jaw hypoplasia, videolaryngoscopy-mediated intubation was chosen. A single-stage T4-L3 posterior corrective fusion with instrumentation was successfully performed. Physical and imaging findings were analyzed up to 2 years after correction. The main thoracic Cobb angle was corrected from 73° to 12° and maintained for 2 years after surgery. The patient's low back pain resolved.

LESSONS

Careful consideration of RTS-associated complications and preoperative planning, including the use of videolaryngoscopy-mediated intubation, anesthesia selection, and postoperative care, proved crucial. Scoliosis may appear in many variations in rare diseases such as RTS. Publication of case reports such as this one is needed to provide detailed information about strategies and considerations for correcting scoliotic deformities in patients with RTS.

Treatment of postoperative vasospasm with intraarterial verapamil after removal of intracranial tumor: patient series

BACKGROUND

The authors report on four clinical cases with intraarterial verapamil administration to resolve vasospasm in patients who underwent surgery for intracranial tumors. Iatrogenic subarachnoid hemorrhage after tumor resection and subsequent vasospasm (an increase in the systolic linear velocity of blood flow through the M1 segment of the middle cerebral artery of more than 250 cm/sec; Lindegaard index: 4.1) were observed in four patients during the early postoperative period after the removal of intracerebral tumors. Each vasospasm case was confirmed by angiography data, was clinically significant, and manifested as the development of a neurological deficit.

OBSERVATIONS

Resolution of vasospasm with the intraarterial administration of verapamil was achieved in all four cases as confirmed by angiographic data in all four cases and complete regression of neurological symptoms in two cases. In all four presented cases, vasospasm was resolved; unfortunately, the resolution did not always lead to significant clinical improvement. However, lethal outcomes were avoided in two cases, and almost full recoveries were achieved in the other two.

LESSONS

The authors believe that the removal of intracranial tumors can cause expected and potential complications, such as cerebral vasospasm, which must be diagnosed and treated in a timely manner.

Multifocal primary central nervous system Ewing sarcoma presenting with intracranial hemorrhage and leptomeningeal dissemination: illustrative case

BACKGROUND

Ewing sarcoma is a neoplasm within the family of small round blue cell tumors and most frequently arises from skeletal bone. Primary involvement of the central nervous system in these lesions is extremely rare, with an incidence of 1%.

OBSERVATIONS

A case is presented of a 34-year-old man who presented with left facial numbness, multiple intracranial lesions, a lumbar intradural lesion, and diffuse spinal leptomeningeal involvement. A lumbar laminectomy and biopsy were performed, which revealed the diagnosis of extraskeletal Ewing sarcoma/primitive neuroectodermal tumor. The patient had a rapidly progressive clinical decline despite total neuroaxis radiation and multiple lines of chemotherapeutic treatments, eventually dying from his disease and its sequelae 6 months after diagnosis.

LESSONS

The authors' review of 40 cases in the literature revealed only 2 patients with isolated intraaxial cranial lesions, 4 patients with cranial and spine involvement, and an additional 34 patients with spine lesions. The unique characteristics of this patient's case, including his presentation with diffuse disease and pathology that included a rare V600E BRAF mutation, are discussed in the context of the available literature.

Endovascular selective hypothermia facilitates giant aneurysm clipping: illustrative case

BACKGROUND

The authors present a case of selective hypothermia used for neuroprotection during clipping of a giant partially thrombosed middle cerebral artery (MCA) aneurysm. Although these cases have traditionally required deep hypothermic cardiac arrest, this case illustrates a novel and entirely endovascular solution that avoids cardiac standstill and whole-body cooling.

OBSERVATIONS

This is, to the authors' knowledge, the first case in human surgery of a catheter-based selective hypothermic circuit used to facilitate MCA trapping for almost 30 minutes. Core temperatures never dropped below 34°C, and the patient recovered uneventfully and has been well for over 5 years.

LESSONS

The technical nuances and physiological changes unique to selective hypothermia are discussed.

Intraoperative contrast-enhanced ultrasound for intramedullary spinal neoplasms: patient series

BACKGROUND

Primary intramedullary spinal tumors cause significant morbidity and death. Intraoperative ultrasound as an adjunct for localization and monitoring the extent of resection has not been systematically evaluated in these patients; the effectiveness of intraoperative contrast-enhanced ultrasound (CEUS) remains almost completely unexplored.

OBSERVATIONS

A retrospective case series of patients at a single institution who had consented to the off-label use of intraoperative CEUS was identified. Seven patients with a mean age of 52.8 ± 15.8 years underwent resection of intramedullary tumors assisted by CEUS performed by a single attending neurosurgeon. Histopathological evaluation revealed 3 cases of hemangioblastoma, 1 case of pilocytic astrocytoma, 2 cases of ependymoma, and 1 case of subependymoma. Contrast enhancement correlated with gadolinium enhancement on preoperative magnetic resonance imaging. Intraoperative CEUS facilitated precise lesion localization and myelotomy planning. Dynamic CEUS studies were useful in demonstrating the blood supply to lesions with a dominant vascular pedicle. Regardless of contrast uptake, the differential enhancement between spinal cord tissue and neoplasm assisted in determining interface boundaries.

LESSONS

Intraoperative CEUS constitutes a useful adjunct for the intraoperative delineation of contrast-enhancing intramedullary tumors and in vivo confirmation of gross-total resection. Systematic investigation is needed to establish the role of CEUS for resection of intramedullary spinal tumors of various pathologies.

Endovascular treatment of a ruptured posterior fossa pure arterial malformation: illustrative case

BACKGROUND

Pure arterial malformations (PAMs) are rare vascular anomalies that are commonly mistaken for other vascular malformations. Because of their purported benign natural history, PAMs are often conservatively managed. The authors report the case of a ruptured PAM leading to subarachnoid hemorrhage (SAH) with intraventricular extension that was treated endovascularly.

OBSERVATIONS

A 38-year-old man presented with a 1-day history of headaches and nausea. A computed tomography scan demonstrated diffuse SAH with intraventricular extension, and angiography revealed a right posterior inferior cerebellar artery-associated PAM. The PAM was treated with endovascular Onyx embolization.

LESSONS

To the authors' knowledge, only 2 other cases of SAH associated with PAM have been reported. In those 2 cases, surgical clipping was pursued for definitive treatment. Here, the authors report the first case of a ruptured PAM treated using an endovascular approach, showing its feasibility as a treatment option particularly in patients in whom open surgery is too high a risk.

Rapid contrast-induced encephalopathy after a small dose of contrast agent: illustrative case

BACKGROUND

Contrast-induced encephalopathy is a rare complication of cerebral angiography with only few cases reported to date. This paper reports on contrast-induced encephalopathy mimicking meningoencephalitis following cerebral angiography with iopromide, a subhypertonic nonionic contrast agent.

OBSERVATIONS

A 50-year-old woman underwent cerebral angiography for assessment of recurrent nasopharyngeal carcinoma with invasion of internal carotid artery. The patient experienced symptoms including a disturbance of consciousness, seizures, frequent blinking, and stiffness in the extremities immediately after angiography of the left common carotid artery using iopromide (4 ml/s, total 6 ml). Computed tomography scans of the brain showed no obvious abnormalities, whereas brain magnetic resonance imaging showed swelling of the left cerebral cortex without signs of ischemia or hemorrhage. The patient was treated with intravenous rehydration, mannitol dehydration, and other supportive treatment. With this treatment, neurological status progressively improved, with complete resolution of symptoms at day 10.

LESSONS

This observation highlights that even a small dose of subhypertonic nonionic contrast agent can rapidly induce contrast encephalopathy.

Neuroendovascular surgery

Neuroendovascular surgery and interventional neuroradiology both describe the catheter-based (most often) endovascular diagnosis and treatment of vascular lesions affecting the brain and spinal cord. This article traces the evolution of these techniques and their current role as the dominant and frequently standard approach for many of these conditions. The article also discusses the important changes that have been brought to bear on open cerebrovascular neurosurgery by neuroendovascular surgery and their effects on resident and fellow training and describes new concepts for clinical care.

Three-stage Gamma Knife treatment for metastatic brain tumors larger than 10 cm3: a 2-institute study including re-analyses of earlier results using competing risk analysis

OBJECTIVEThe results of 3-stage Gamma Knife treatment (3-st-GK-Tx) for relatively large brain metastases have previously been reported for a series of patients in Chiba, Japan (referred to in this study as the C-series). In the current study, the authors reappraised, using a competing risk analysis, the efficacy and safety of 3-st-GK-Tx by comparing their experience with that of the C-series.METHODSThis was a retrospective cohort study. Among 1767 patients undergoing GK radiosurgery for brain metastases at Mito Gamma House during the 2005-2015 period, 78 (34 female, 44 male; mean age 65 years, range 35-86 years) whose largest tumor was > 10 cm3, treated with 3-st-GK-Tx, were studied (referred to in this study as the M-series). The target volumes were covered with a 50% isodose gradient and irradiated with a peripheral dose of 10 Gy at each procedure. The interval between procedures was 2 weeks. Because competing risk analysis had not been employed in the published C-series, the authors reanalyzed the previously published data using this method.RESULTSThe overall median survival time after 3-st-GK-Tx was 8.3 months (95% CI 5.6-12.0 months) in the M-series and 8.6 months (95% CI 5.5-10.6 months) in the C-series (p = 0.41). Actuarial survival rates at the 6th and 12th post-3-st-GK-Tx months were, respectively, 55.1% and 35.2% in the M-series and 62.5% and 26.4% in the C-series (HR 1.175, 95% CI 0.790-1.728, p = 0.42). Cumulative incidences at the 12th post-3-st-GK-Tx, determined by competing risk analyses, of neurological deterioration (14.2% in C-series vs 12.8% in M-series), neurological death (7.2% vs 7.7%), local recurrence (4.8% vs 6.2%), repeat SRS (25.9% vs 18.0%), and SRS-related complications (2.3% vs 5.1%) did not differ significantly between the 2 series.CONCLUSIONSThere were no significant differences in post-3-st-GK-Tx results between the 2 series in terms of overall survival times, neurological death, maintained neurological status, local control, repeat SRS, and SRS-related complications. The previously published results (C-series) are considered to be validated by the M-series results.

Recurrent desmoid-type fibromatosis associated with underlying neuromuscular choristoma

OBJECTIVE

Desmoid-type fibromatosis (DTF) presents a therapeutic dilemma. While lacking metastatic potential, it is a locally aggressive tumor with a strong propensity for occurrence near nerve(s) and recurrence following resection. In this study, the authors introduce the association of an occult neuromuscular choristoma (NMC) identified in patients with DTF.

METHODS

After experiencing a case of DTF found to have an occult NMC, the authors performed a retrospective database review of all other cases of biopsy-proven DTF involving the extremities or limb girdles in patients with available MRI data. Two musculoskeletal radiologists with expertise in peripheral nerve imaging reviewed the MRI studies of the eligible cases for evidence of previously unrecognized NMC.

RESULTS

The initial case of a patient with an occult sciatic NMC is described. The database review yielded 40 patients with DTF-18 (45%) in the upper limb and 22 (55%) in the lower limb. Two cases (5%) had MRI findings of NMC associated with the DTF, one in the proximal sciatic nerve and the other in the proximal tibial and sural nerves.

CONCLUSIONS

The coexistence of NMC may be under-recognized in a subset of patients with extremity DTF. This finding poses implications for DTF treatment and the likelihood of recurrence after resection or biopsy. Further study may reveal crucial links between the pathogenesis of NMC and DTF and offer novel therapeutic strategies.

The value of visible 5-ALA fluorescence and quantitative protoporphyrin IX analysis for improved surgery of suspected low-grade gliomas

OBJECTIVE

In patients with suspected diffusely infiltrating low-grade gliomas (LGG), the prognosis is dependent especially on extent of resection and precision of tissue sampling. Unfortunately, visible 5-aminolevulinic acid (5-ALA) fluorescence is usually only present in high-grade gliomas (HGGs), and most LGGs cannot be visualized. Recently, spectroscopic probes were introduced allowing in vivo quantitative analysis of intratumoral 5-ALA-induced protoporphyrin IX (PpIX) accumulation. The aim of this study was to intraoperatively investigate the value of visible 5-ALA fluorescence and quantitative PpIX analysis in suspected diffusely infiltrating LGG.

METHODS

Patients with radiologically suspected diffusely infiltrating LGG were prospectively recruited, and 5-ALA was preoperatively administered. During resection, visual fluorescence and absolute tissue PpIX concentration (CPpIX) measured by a spectroscopic handheld probe were determined in different intratumoral areas. Subsequently, corresponding tissue samples were safely collected for histopathological analysis. Tumor diagnosis was established according to the World Health Organization 2016 criteria. Additionally, the tumor grade and percentage of tumor cells were investigated in each sample.

RESULTS

All together, 69 samples were collected from 22 patients with histopathologically confirmed diffusely infiltrating glioma. Visible fluorescence was detected in focal areas in most HGGs (79%), but in none of the 8 LGGs. The mean CPpIX was significantly higher in fluorescing samples than in nonfluorescing samples (0.693 μg/ml and 0.008 μg/ml, respectively; p < 0.001). A significantly higher mean percentage of tumor cells was found in samples with visible fluorescence compared to samples with no fluorescence (62% and 34%, respectively; p = 0.005), and significant correlation of CPpIX and percentage of tumor cells was found (r = 0.362, p = 0.002). Moreover, high-grade histology was significantly more common in fluorescing samples than in nonfluorescing samples (p = 0.001), whereas no statistically significant difference in mean CPpIX was noted between HGG and LGG samples. Correlation between maximum CPpIX and overall tumor grade was highly significant (p = 0.005). Finally, 14 (40%) of 35 tumor samples with no visible fluorescence and 16 (50%) of 32 LGG samples showed significantly increased CPpIX (cutoff value: 0.005 μg/ml).

CONCLUSIONS

Visible 5-ALA fluorescence is able to detect focal intratumoral areas of malignant transformation, and additional quantitative PpIX analysis is especially useful to visualize mainly LGG tissue that usually remains undetected by conventional fluorescence. Thus, both techniques will support the neurosurgeon in achieving maximal safe resection and increased precision of tissue sampling during surgery for suspected LGG.Clinical trial registration no.: NCT01116661 (clinicaltrials.gov).

Detection of microbleeds associated with sentinel headache using MRI quantitative susceptibility mapping: pilot study

OBJECTSentinel headaches (SHs) associated with cerebral aneurysms (CAs) could be due to microbleeds, which are considered a sign that an aneurysm is unstable. Despite the prognostic importance of these microbleeds, they remain difficult to detect using routine imaging studies. The objective of this pilot study is to detect microbleeds associated with SH using a magnetic resonance imaging (MRI) quantitative susceptibility mapping (QSM) sequence and then evaluate the morphological characteristics of unstable aneurysms with microbleeds.METHODSTwenty CAs in 16 consecutive patients with an initial presentation of headache (HA) leading to a diagnosis of CA were analyzed. Headaches in 4 of the patients (two of whom had 2 aneurysms each) met the typical definition of SH, and the other 12 patients (two of whom also had 2 aneurysms each) all had migraine HA. All patients underwent imaging with the MRI-QSM sequence. Two independent MRI experts who were blinded to the patients' clinical history performed 3D graphical analysis to evaluate for potential microbleeds associated with these CAs. Computational flow and morphometric analyses were also performed to estimate wall shear and morphological variables.RESULTSIn the 4 patients with SH, MRI-QSM results were positive for 4 aneurysms, and hence these aneurysms were considered positive for non-heme ferric iron (microbleeds). The other 16 aneurysms were negative. Among aneurysm shape indices, the undulation index was significantly higher in the QSM-positive group than in the QSM-negative group. In addition, the spatial averaged wall shear magnitude was lower in the aneurysm wall in direct contact with microbleeds.CONCLUSIONSMRI-QSM allows for objective detection of microbleeds associated with SH and therefore identification of unstable CAs. CAs with slightly greater undulation indices are associated with positive MRI-QSM results and hence with microbleeds. Studies with larger populations are needed to confirm these preliminary findings.

Prediction of clinical outcome in subacute subarachnoid hemorrhage using diffusion tensor imaging

OBJECTIVEClinical outcome in nontraumatic subarachnoid hemorrhage (SAH) is multifactorial and difficult to predict. Diffusion tensor imaging (DTI) findings are a prognostic marker in some diseases such as traumatic brain injury. The authors hypothesized that DTI parameters measured in the subacute phase of SAH can be associated with a poor clinical outcome.METHODSDiffusion tensor imaging was prospectively performed in 54 patients at 8-10 days after nontraumatic SAH. Logistic regression analysis was performed to evaluate the association of fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values with a poor clinical outcome (modified Rankin Scale score ≥ 3) at 3 months.RESULTSAt 8-10 days post-SAH, after adjusting for other variables associated with a poor outcome, an increased ADC at the frontal centrum semiovale was associated with a poor prognosis (OR estimate 1.29, 95% CI 1.04-1.60, p = 0.020). Moreover, an increase of 0.1 in the FA value at the corpus callosum at 8-10 days after SAH corresponded to 66% lower odds of having a poor outcome (p = 0.002).CONCLUSIONSDecreased FA and increased ADC values in specific brain regions were independently associated with a poor clinical outcome after SAH. This preliminary exploratory study supports a potential role for DTI in predicting the outcome of SAH.

Graph theory analysis of complex brain networks: new concepts in brain mapping applied to neurosurgery

Neuroanatomy has entered a new era, culminating in the search for the connectome, otherwise known as the brain's wiring diagram. While this approach has led to landmark discoveries in neuroscience, potential neurosurgical applications and collaborations have been lagging. In this article, the authors describe the ideas and concepts behind the connectome and its analysis with graph theory. Following this they then describe how to form a connectome using resting state functional MRI data as an example. Next they highlight selected insights into healthy brain function that have been derived from connectome analysis and illustrate how studies into normal development, cognitive function, and the effects of synthetic lesioning can be relevant to neurosurgery. Finally, they provide a précis of early applications of the connectome and related techniques to traumatic brain injury, functional neurosurgery, and neurooncology.

Magnetic resonance imaging as an alternative to computed tomography in select patients with traumatic brain injury: a retrospective comparison

OBJECT

Traumatic head injury (THI) is a highly prevalent condition in the United States, and concern regarding excess radiation-related cancer mortality has placed focus on limiting the use of CT in the evaluation of pediatric patients with THI. Given the success of rapid-acquisition MRI in the evaluation of ventriculoperitoneal shunt malfunction in pediatric patient populations, this study sought to evaluate the sensitivity of MRI in the setting of acute THI.

METHODS

Medical records of 574 pediatric admissions for THI to a Level 1 trauma center over a 10-year period were retrospectively reviewed to identify patients who underwent both CT and MRI examinations of the head within a 5-day period. Thirty-five patients were found, and diagnostic images were available for 30 patients. De-identified images were reviewed by a neuroradiologist for presence of any injury, intracranial hemorrhage, diffuse axonal injury (DAI), and skull fracture. Radiology reports were used to calculate interrater reliability scores. Baseline demographics and concordance analysis was performed with Stata version 13.

RESULTS

The mean age of the 30-patient cohort was 8.5 ± 6.7 years, and 63.3% were male. The mean Injury Severity Score was 13.7 ± 9.2, and the mean Glasgow Coma Scale score was 9 ± 5.7. Radiology reports noted 150 abnormal findings. CT scanning missed findings in 12 patients; the missed findings included DAI (n = 5), subarachnoid hemorrhage (n = 6), small subdural hematomas (n = 6), cerebral contusions (n = 3), and an encephalocele. The CT scan was negative in 3 patients whose subsequent MRI revealed findings. MRI missed findings in 13 patients; missed findings included skull fracture (n = 5), small subdural hematomas (n = 4), cerebral contusions (n = 3), subarachnoid hemorrhage (n = 3), and DAI (n = 1). MRI was negative in 1 patient whose preceding CT scan was read as positive for injury. Although MRI more frequently reported intracranial findings than CT scanning, there was no statistically significant difference between CT and MRI in the detection of any intracranial injury (p = 0.63), DAI (p = 0.22), or intracranial hemorrhage (p = 0.25). CT scanning tended to more frequently identify skull fractures than MRI (p = 0.06).

CONCLUSIONS

MRI may be as sensitive as CT scanning in the detection of THI, DAI, and intracranial hemorrhage, but missed skull fractures in 5 of 13 patients. MRI may be a useful alternative to CT scanning in select stable patients with mild THI who warrant neuroimaging by clinical decision rules.