Excess intracellular ATP causes neuropathic pain following spinal cord injury.

Intractable neuropathic pain following spinal cord injury (NP-SCI) reduces a patient's quality of life. Excessive release of ATP into the extracellular space evokes neuroinflammation via purinergic receptor. Neuroinflammation plays an important role in the initiation and maintenance of NP. However, little is known about whether or not extracellular ATP cause NP-SCI. We found in the present study that excess of intracellular ATP at the lesion site evokes at-level NP-SCI. No significant differences in the body weight, locomotor function, or motor behaviors were found in groups that were negative and positive for at-level allodynia. The intracellular ATP level at the lesion site was significantly higher in the allodynia-positive mice than in the allodynia-negative mice. A metabolome analysis revealed that there were no significant differences in the ATP production or degradation between allodynia-negative and allodynia-positive mice. Dorsal horn neurons in allodynia mice were found to be inactivated in the resting state, suggesting that decreased ATP consumption due to neural inactivity leads to a build-up of intracellular ATP. In contrast to the findings in the resting state, mechanical stimulation increased the neural activity of dorsal horn and extracellular ATP release at lesion site. The forced production of intracellular ATP at the lesion site in non-allodynia mice induced allodynia. The inhibition of P2X4 receptors in allodynia mice reduced allodynia. These results suggest that an excess buildup of intracellular ATP in the resting state causes at-level NP-SCI as a result of the extracellular release of ATP with mechanical stimulation.

[Two Cases of Venous Malformation of the Orbit Treated by Endoscopic Endonasal Surgery].

Venous malformation of the orbit(VMO), previously called orbital cavernous hemangioma, has been classified as a vascular malformation according to the International Society for the Study of Vascular Anomalies. Among various surgical approaches for VMO, endoscopic endonasal surgery(EES)has recently been developed, especially for those in the inferomedial quadrant of the orbit. Two 67-year-old and 69-year-old women presented with decreased visual acuity and visual field deficit, respectively. Their CT and MRI scans revealed retrobulbar masses, suggestive of the inferomedial type of VMO. The first case was diagnosed as an intraconal VMO, and subtotal removal was achieved through binostril EES using a two-surgeon four-handed technique after palliative partial resection through a prior frontal craniotomy. In the second case, diagnosed as an extraconal VMO, total en bloc removal was achieved using the same surgical technique as above. In both cases, the visual functions improved after the procedures, with uneventful postoperative courses. Although the inferomedial VMO is an uncommon type, EES is well indicated for this condition. The international consensus of surgical techniques and staging from a surgical point of view should be established in the near future.

[Consciousness Impairment and Left Hemiparesis due to Contrast Medium in the Coil Embolization of Unruptured Large Right Middle Cerebral Artery Aneurysm: A Case Report].

Neurological deficits following coil embolization of anterior circulation aneurysms due to the toxicity of contrast medium are rare. Here, we describe a patient with mild consciousness impairment and left hemiparesis following coil embolization of a large right middle cerebral artery aneurysm without evidence of ischemia or hemorrhage, who recovered completely with conservative treatment. The patient's clinical course and radiological findings led us to conclude that the neurological deficits were due to the toxic effect of contrast medium used during the coil embolization.

[A Girl with Intraorbital Varix: A Case Report].

We report a case of intraorbital varix. A 16-year-old girl showed sudden left-sided exophthalmos after vomiting. After several episodes of vomiting, she developed complete loss of vision in the left eye, followed by orbital pain, disruption of eye movement, and periorbital swelling. No change in symptoms or signs was observed after the Valsalva maneuver or jugular vein compression. Computed tomography (CT), magnetic resonance imaging (MRI), and angiography were inconclusive. Transcranial surgery revealed a large varix near the optic nerve. The lesion could not be completely resected because the orbital fat interfered with its complete visualization. We cauterized the lesion to reduce its volume. The patient's symptoms improved markedly after surgery and cauterization. Thus, cauterization appears to be an effective strategy to reduce the volume of an unresectable intraorbital varix.

A Sufficient Surgical Window for Deep-Seated Extracranial Schwannomas in the Craniocervical Junction by the Anterolateral Approach.

Care should be taken regarding surrounding anatomic structures during access to deepseated extracranial schwannomas in the craniocervical junction (CCJ). Herein, we present surgical tips for extracranial schwannomas in the CCJ using the anterolateral approach. A retrospective review was performed of 3 cases of surgical treatment of extracranial schwannomas in the CCJ by the anterolateral approach, which is a presternomastoid retrojugular route to the CCJ. The combination of neck rotation and reflection of the sternocleidomastoid muscle presented a sufficient, shallow surgical field for the CCJ. We could identify tumors along the accessory nerves and internal jugular veins, and had sufficient rostrocaudal working space to resect the tumors. Two cases were enucleated total resection and 1 was subtotal resection. Two patients experienced transient postoperative vocal cord partial paralysis and 1 had transient dysphagia. These neurological complications improved within 1 month. The anterolateral approach can provide a shallow and sufficient rostral and caudal surgical window.

Conservative and Surgical Management of Spinal Cord Cavernous Malformations.

OBJECTIVES: We present a case series of spinal cord cavernous malformations (SCCMs) to describe clinical presentation and outcomes of both surgical and conservative management. METHODS: The clinical courses of patients diagnosed with SCCMs at our institution were retrospectively reviewed. Neurologic symptoms were evaluated using the Modified McCormick Scale. RESULTS: A total of 18 patients were identified. Five patients (27.8%) presented with acute onset bleeding, 4 of whom underwent immediate surgical resection. Thirteen patients (72.2%) were initially managed conservatively. Eight patients (38.9%) developed a hemorrhage during follow-up, and 8 (38.9%) required surgical resection due to bleeding or neurological worsening. The mean (range) duration from primary symptoms to subsequent hemorrhage or deterioration of symptoms was 1.42 (range: 0.25-4.33) years. The mean duration from primary symptoms to surgery was 2.10 (range: 0.25-5.0) years. No patients experienced subsequent hemorrhage after surgical resection. Eleven patients (84.6%) in the surgery group showed improved neurological status, and 2 patients (15.4%) remained unchanged. The annualized subsequent hemorrhage risk was 3.7%. Patients in the immediate surgical group had a significantly larger lesion compared with those in the conservative group. There was significance between the worst Modified McCormick Scale grades at the time of debilitating symptoms and the length of hemorrhage, but not the size of the lesion. CONCLUSIONS: Surgery for SCCMs resulted in no recurrence of hemorrhage or exacerbation of neurological symptoms, and should be considered for patients who experienced acute onset of hemorrhage or debilitating symptoms during follow-up.