Neuronavigation Applied to Piezosurgery: Toward Robotic Image-Aided Craniotomy? A Technical Note.

BACKGROUND: Although simple in its concept, craniotomy can still cause serious consequences to the patient. A recent alternative to standard techniques (i.e., perforator and craniotome) is represented by piezosurgery (PS), which exploits a microvibration-emitting blade that cuts the bone directly from the outer surface of the skull. Although PS has been demonstrated to decrease complications, dural lacerations and neurovascular injuries are still possible from inadvertent penetration of the inner tabula. Modern neuronavigation systems can provide the surgeon with the possibility to track the instrument while carving the skull, thus potentially lowering the complication rates. METHODS: Two cases of miniretromastoid craniotomy for trigeminal neuralgia were performed using neuronavigated PS. Before surgery, the patients underwent volumetric brain magnetic resonance imaging and computed tomography. The piezosurgical cutter was registered on the S8 StealthStation neuronavigation system (Medtronic, Dublin, Ireland) using the step-by-step cranial standard instrument calibration protocol. RESULTS: The craniotomy was performed with the surgeon using the neuronavigation monitor to visualize both the position and the trajectory of the instrument's blade while penetrating the bone. No dural lacerations or neurovascular injuries were reported. At the end of the procedure, the bone flaps were perfectly repositioned within their craniotomy margins without the use of cranial fixation devices. CONCLUSIONS: Neuronavigated PS has the potential to decrease craniotomy-related complication rates. By allowing for real-time visualization of the blade's level of penetration, it provides the surgeon with the ability to halt progression when needed, avoiding dural lacerations and neurovascular injuries. The principles behind this technique could anticipate the advent of robotic-image aided craniotomy.

The Role of Bypass Surgery for the Management of Complex Intracranial Aneurysms in the Anterior Circulation in the Flow-Diverter Era: A Single-Center Series.

Despite the increasing popularity of flow diverters (FDs) as an endovascular option for intracranial aneurysms, the treatment of complex aneurysms still represents a challenge. Combined strategies using a flow-preservation bypass could be considered in selected cases. In this study, we retrospectively reviewed our series of patients with complex intracranial aneurysms submitted to bypass. From January 2015 to May 2022, 23 patients were selected. We identified 11 cases (47.8%) of MCA, 6 cases (26.1%) of ACA and 6 cases (26.1%) of ICA aneurysms. The mean maximal diameter was 22.73 ± 12.16 mm, 8 were considered as giant, 9 were fusiform, 8 presented intraluminal thrombosis, 10 presented wall calcification, and 18 involved major branches or perforating arteries. Twenty-five bypass procedures were performed in 23 patients (two EC-IC bypasses with radial artery graft, seventeen single- or double-barrel STA-MCA bypasses and six IC-IC bypasses in anterior cerebral arteries). The long-term bypass patency rate was 94.5%, and the total aneurysm exclusion was 95.6%, with a mean follow-up of 28 months. Median KPS values at last follow-up was 90, and a favorable outcome (KPS ≥ 70 and mRS ≤ 2) was obtained in 87% of the cases. The use of bypass techniques represents, in selected cases, a valid therapeutic option in the management of complex anterior circulation aneurysms when a simpler direct approach, including the use of FD, is considered not feasible.

Confocal Laser Microscopy in Neurosurgery: State of the Art of Actual Clinical Applications.

Achievement of complete resections is of utmost importance in brain tumor surgery, due to the established correlation among extent of resection and postoperative survival. Various tools have recently been included in current clinical practice aiming to more complete resections, such as neuronavigation and fluorescent-aided techniques, histopathological analysis still remains the gold-standard for diagnosis, with frozen section as the most used, rapid and precise intraoperative histopathological method that permits an intraoperative differential diagnosis. Unfortunately, due to the various limitations linked to this technique, it is still unsatisfactorily for obtaining real-time intraoperative diagnosis. Confocal laser technology has been recently suggested as a promising method to obtain near real-time intraoperative histological data in neurosurgery, due to its established use in other non-neurosurgical fields. Still far to be widely implemented in current neurosurgical clinical practice, this technology was initially studied in preclinical experiences confirming its utility in identifying brain tumors, microvasculature and tumor margins. Hence, ex vivo and in vivo clinical studies evaluated the possibility with this technology of identifying and classifying brain neoplasms, discerning between normal and pathologic tissue, showing very promising results. This systematic review has the main objective of presenting a state-of-the-art summary on actual clinical applications of confocal laser imaging in neurosurgical practice.

Characteristics of Moyamoya Disease in the Older Population: Is It Possible to Define a Typical Presentation and Optimal Therapeutical Management?

Whereas several studies have been so far presented about the surgical outcomes in terms of mortality and perioperative complications for elderly patients submitted to neurosurgical treatments, the management of elderly moyamoya patients is unclear. This review aims to explore the available data about the clinical manifestation, characteristics, and outcome after surgery of older patients with moyamoya arteriopathy (MA). We found only two articles strictly concerning elderly patients with MA. We have also evaluated other reported adult series of moyamoya patients, including elderly cases in their analysis. Patients with MA above 50 years old may be considered a peculiar subset in which patients are often presenting with ischemic symptoms and a higher Suzuki grade. Conservative treatment may be proposed in asymptomatic or stable cases due to their fragility and possible increase of post-operative complications, while the best surgical options in symptomatic cases are still under investigation, although we believe that a minimal invasive superficial temporal artery-middle cerebral artery bypass could be considered the treatment of choice for the immediate effect on brain perfusion with a limited rate of post-operative complications.

Trigeminal interfascicular neurolysis (nerve combing) for refractory recurrent neuralgia in multiple sclerosis.

In multiple sclerosis (MS) patients, trigeminal neuralgia (TN) represents a challenging syndrome to treat, often refractory to medical therapy and percutaneous techniques. Despite the frequent lack of a neurovascular conflict, the trigeminal nerve's axons are often damaged, with the myelin sheath permanently degenerated, thus explaining the difficulty in treating TN in MS. The authors illustrate trigeminal interfascicular neurolysis (the combing technique) to control refractory recurrent TN in MS: the nerve is longitudinally divided along its fibers from the root entry zone, determining good pain relief. The video can be found here: https://youtu.be/o1XksPW5fMY.