Selective motor fascicle transfer and neural-machine interface: case report.

An amputated nerve transferred to a nearby muscle produces a transcutaneously detectable electromyographic signal corresponding to the transferred nerve; this technique is known as targeted muscle reinnervation (TMR). There are 2 issues to overcome to improve this technique: the caliber and the selectivity of the transferred nerve. It is optimal to select and transfer each motor fascicle to achieve highly developed myoelectric arms with multiple degrees-of-freedom motion. The authors report on a case in which they first identified the remnant stumps of the amputated median and radial nerves and then identified the sensory fascicles using somatosensory evoked potentials. Each median nerve fascicle was transferred to the long head branch of the biceps or the brachialis branch, while the short head branch of the biceps was retained for elbow flexion. Each radial nerve fascicle was transferred to the medial or lateral head branch of the triceps, while the long head branch of the triceps was retained for elbow extension. Electrophysiological and functional tests were conducted in the reinnervated muscles. Functional and electrophysiological improvement was noted, with marked improvement in the identification rate for each digit, forearm, and elbow motion after the selective nerve transfers. The authors note that more selective nerve transfers may be required for the development of prostheses with multiple degrees of freedom.

Effectiveness of Low-Dose Intravenous Tissue Plasminogen Activator before Stent Retriever or Aspiration Mechanical Thrombectomy.

PURPOSE: To determine whether thrombolysis with a lower dose of intravenous recombinant tissue plasminogen activator before mechanical thrombectomy is beneficial for functional outcomes compared with mechanical thrombectomy alone. MATERIALS AND METHODS: Data for 100 Japanese patients who underwent mechanical thrombectomy between July 2014 and November 2017 were retrospectively reviewed. These patients were divided into groups according to whether they received intravenous thrombolysis before mechanical thrombectomy, and outcomes were compared. Favorable outcome was defined as a modified Rankin scale score ≤ 2 at 3 months after treatment. RESULTS: Thirty-four patients for the thrombolysis group and 66 patients for the thrombectomy-only group were identified. The thrombolysis and nonthrombolysis groups did not differ significantly in baseline characteristics (mean age, 74.3 y vs 75.7 y [P = .485]; mean preoperative National Institute Health Stroke Scale score, 19.8 vs 19.6 [P = .825]). There were no significant differences in the times required for, or the rates of, successful recanalization. However, the thrombolysis group had a higher rate of complete recanalization (67.6% vs 43.9%; P = .041). Postoperative symptomatic intracranial hemorrhage was not significantly different between groups. Favorable outcomes were observed in 73.5% of patients in the thrombolysis group and 51.5% in the nonthrombolysis group (P = .028). CONCLUSIONS: This single-center retrospective study shows that lower-dose intravenous thrombolysis improves the outcomes of mechanical thrombectomy for Japanese patients with acute anterior-circulation stroke treated within 4.5 hours of onset.

Severe Vasospasm of the Middle Cerebral Artery after Mechanical Thrombectomy Due to Infective Endocarditis: An Autopsy Case.

Untreated infective endocarditis (IE) often produces infective emboli in major cerebral arteries. We describe a case of middle cerebral artery occlusion due to IE, which caused severe vasospasm and reocclusion after mechanical thrombectomy (MT). We present the pathologic findings of the occluded middle cerebral artery and investigate the precautions to be taken while performing MT due to IE. A 72-year-old man with atrial fibrillation treated with dabigatran presented with right hemiparesis and aphasia. A diffusion-weighted image showed a high-intensity area in the left temporoparietal junction, and magnetic resonance angiography revealed a left M2 occlusion. Because of an elevated activated partial thromboplastin time, the thrombolytic therapy was contraindicated; instead, MT was performed. Just after the withdrawal of a stent retriever, the left M2 segment showed severe vasospasm. The next day, the left M2 segment reoccluded. Transthoracic echocardiogram and blood culture findings revealed IE. On the ninth day, the patient died. According to the autopsy report, the cause of death was pulmonary embolism. Pathologic analysis of the occluded M2 segment revealed fibrin thrombi containing vast amounts of neutrophils and invasion of neutrophils into the internal elastic lamina. Severe vasospasm was thought to have occurred because the vascular injury caused by the stent retriever in the vessel had a marked inflammation background. Our findings suggest that devices that are less invasive to the vascular wall are required for performing MT due to IE. The Penumbra aspiration system is thought to be a suitable device.