High-resolution ultrasonography is a noninvasive, readily applicable imaging modality, capable of depicting real-time static and dynamic morphological information concerning the peripheral nerves and their surrounding tissues. Continuous progress in ultrasonographic technology results in highly improved spatial and contrast resolution. Therefore, nerve imaging is possible to a fascicular level, and most peripheral nerves can now be depicted along their entire anatomical course. An increasing number of publications have evaluated the role of high-resolution ultrasonography in peripheral nerve diseases, especially in peripheral nerve entrapment. Ultrasonography has been shown to be a precious complementary tool for assessing peripheral nerve lesions with respect to their exact location, course, continuity, and extent in traumatic nerve lesions, and for assessing nerve entrapment and tumors. In this article, the authors discuss the basic technical considerations for using ultrasoniography in peripheral nerve assessment, and some of the clinical applications are illustrated.

Object: Surgical treatment of nerve lesions in continuity remains difficult, even in the most experienced hands. The regenerative potential of those injuries can be evaluated by intraoperative electrophysiological studies and/or intraneural dissection. The present study examines the value of intraoperative high-frequency ultrasound as an imaging tool for decision making in the management of traumatic nerve lesions in continuity. Methods: Intraoperative high-frequency ultrasound was applied to 19 traumatic or iatrogenic nerve lesions of differing extents. The information obtained was correlated with intraoperative electrophysiological, microsurgical intraneural dissection, and histopathological findings in resected nerve segments. Results: The intraoperative application of high-resolution, high-frequency ultrasound enabled morphological examination of nerve lesions in continuity, with good image quality. The assessment of the severity of the underlying nerve injury matched perfectly with the judgment obtained from intraoperative electrophysiological studies. Both intraneural nerve dissection and neuropathological examination of the resected nerve segments confirmed the sonographic findings. In addition, intraoperative ultrasound proved to be very time efficient. Conclusions: With intraoperative ultrasound, the extent of traumatic peripheral nerve lesions can be examined morphologically for the first time. It is a promising, noninvasive method that seems capable of assessing the type (intraneural/perineural) and grade of nerve fibrosis. Therefore, in combination with intraoperative neurophysiological studies, intraoperative high-resolution ultrasound may represent a major tool for noninvasive assessment of the regenerative potential of a nerve lesion.

Cerebral vasospasm (CVS) is associated with delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (SAH). The most frequently used form of rescue therapy for CVS is invasive endovascular therapy. Due to a lack of prospective data, we performed a prospective randomized multicenter trial (NCT01400360). A total of 34 patients in three centers were randomized to invasive endovascular treatment or conservative therapy at diagnosis of relevant CVS onset. Imaging data was assessed by a neuroradiologist blinded for treatment allocation. Primary outcome measure was development of DCI. Secondary endpoints included clinical outcome at 6 months after SAH. A total of 18 of the 34 patients were treated conservatively, and 16 patients were treated with invasive endovascular treatment for CVS. There was no statistical difference in the rate of cerebral infarctions either at initial or at the follow-up MRI between the groups. However, the outcome at 6 months was better in patients treated conservatively (mRs 2 ± 1.5 vs. 4 ± 1.8, p = 0.005). Invasive endovascular treatment for CVS does not lead to a lower rate of DCI but might lead to poorer outcomes compared to induced hypertension. The potential benefits of endovascular treatment for CVS need to be addressed in further studies, searching for a subgroup of patients who may benefit.

Objective: Endovascular treatment of cerebral aneurysms with detachable coils has proven to be a save and effective treatment. But long-term recurrence due to aneurysm regrowth or coil compaction has been reported in up to thirty percent of cases. Therefore a growing number of previously coiled aneurysms have to be retreated by coiling or, in some circumstances, by clipping. We present a consecutive series of ten patients who underwent surgical clipping for recurrent aneurysms after primary coil embolization. Methods: During a 4-year period ten patients with intracranial aneurysms previously treated by coil embolization underwent surgery for clipping of recanalized aneurysms. All aneurysms were located in the anterior circulation (internal carotid artery [ICA], 2; middle cerebral artery [MCA], 3; anterior communicating artery [AcomA], 5). Clinical data and imaging studies of the patients were analyzed retrospectively. Results: All recurrences were detected by routine control angiograms within a median period of 14 months after primary treatment. In three aneurysms treated for SAH dense arachnoid scarring around the aneurysm sac was noted. In four cases, coils were found intraoperatively to be extruding through the aneurysm sac into the subarachnoid space. Each aneurysm could be clipped without affecting the perfusion of the parent vessel. In one patient the aneurysm sac including the coil package was resected. In one patient one of the central anteromedial arteries was injured during dissection due to dense arachnoid scarring because of prior SAH. As a consequence infarction of the head of the caudate nucleus without neurological compromise was observed on follow-up CT scans. Another patient developed transient aphasia due to vasospasm in the early postoperative period with complete restitution. In the end all patients had an uneventful recovery. Removal of the coil package was not necessary in most cases. Clipping of the aneurysm neck was possible even in cases with coil dislocation into the parent vessel. Conclusion: Clipping of previously coiled aneurysms is a unique problem for vascular neurosurgeons. In most cases clipping is feasible. Clipping should still be considered as a definite treatment option in previously coiled recurrent aneurysms. Results in this small series were good. Ziel: Die endovaskuläre Coilembolisation intrakranieller Aneurysmen gilt inzwischen als sicher und effektiv. Angiographische Langzeitstudien haben allerdings eine Rekanalisierungsrate gecoilter Aneurysmen von bis zu 30% beschrieben. Deshalb müssen rekanalisierte endovaskulär behandelte Aneurysmen zunehmend entweder durch erneute Coilembolisation, oder in bestimmten Fällen durch mikrochirurgisches Clipping behandelt werden. Wir präsentieren eine Serie von zehn Patienten, bei denen auf Grund einer Aneurysmarekanalisation nach primärer Coilembolisation ein Aneurysma-Clipping durchgeführt wurde. Methode: Die retrospektive Studie über einen Zeitraum von 4 Jahren umfasst zehn Patienten, die nach primärer Coilembolisation auf Grund einer Aneurysmareperfusion offen mikrochirurgisch geclippt wurden. Es handelte sich ausschließlich um Aneurysmen des vorderen Kreislaufs. Resultate: Alle Aneurysmareperfusionen wurden anlässlich von routinemäßigen Kontrollangiographien (Median 14 Monate) entdeckt. Bei 3 Aneurysmen, welche initial durch eine Ruptur mit konsekutiver SAB symptomatisch wurden, war die Aneurysmapräparation durch ausgedehnte arachnoidale Vernarbungen erschwert. Intraoperativ konnte in vier Fällen Coilmaterial außerhalb des eigentlichen Aneurysmasacks im Subarachnoidalraum gefunden werden. Jedes Aneurysma konnte durch einen Clip versorgt werden, ohne Beeinträchtigung der Perfusion des aneurysmatragenden Gefäßes. Bei einem Patienten wurde das Aneurysma inklusive Coil-Paket reseziert. Bei einem Patienten mit ausgedehnter arachnoidaler Vernarbung kam es bei der Präparation zu einer Verletzung einer der Aa. centrales anteromediales mit konsekutivem, klinisch folgenlosem Infarkt des Nucleus caudatus. Ein anderer entwickelte in der frühen postoperativen Phase einen symptomatischen Vasospasmus mit transienter Sprachproduktionsstörung, welche sich rasch und ohne Residuum zurückbildete. Schließlich boten alle Patienten ein zufriedenstellendes klinisches Endergebnis. Die Entfernung von Coilmaterial aus dem Aneurysma war in den meisten Fällen nicht erforderlich. Sogar im Fall einer Coildislokation in das aneurysmatragende Gefäß war ein Verschluss des Aneurysmahalses durch einen geeigneten Clip möglich. Schlussfolgerung: Die offene chirurgische Behandlung zuvor embolisierter intrakranieller Aneurysmen stellt ein einzigartiges Problem für vaskulär tätige Neurochirurgen dar. In den meisten Fällen ist eine Ausschaltung des Aneurysmas durch ein Clipping möglich. Das mikrochirurgische Clipping zuvor embolisierter intrakranieller Aneurysmen sollte neben wiederholten endovaskulären Maßnahmen als Therapieoption dieser meist komplexen Läsionen mit in Betracht gezogen werden.