A comparison of haemodynamics between subcranial-intracranial bypass and the traditional extracranial-intracranial bypass

Maxillary Nerve as Landmark for Exposure of the Internal Maxillary Artery in Extracranial-Intracranial Bypass Surgery

OBJECTIVE

To establish a new method for fast exposure of the internal maxillary artery (IMA) during extracranial-intracranial bypass surgery.

METHODS

To explore the positional relationship between the IMA and the maxillary nerve and pterygomaxillary fissure, 11 formalin-fixed cadaveric specimens were dissected. Three bone windows of the middle fossa were created for further analysis. Then the IMA length that could be pulled up above the middle fossa was measured after different degrees of removal of bony structure. The IMA branches under each bone window were also explored in detail.

RESULTS

The top of the pterygomaxillary fissure was located 11.50 mm anterolateral to the foramen rotundum. The IMA could be identified just inferior to the infratemporal segment maxillary nerve in all specimens. After drilling of the first bone window, the IMA length that could be pulled above the middle fossa bone was 6.85 mm. After drilling of the second bone window and further mobilization, the IMA length that could be harvested was significantly longer (9.04 mm vs. 6.85 mm; P < 0.001). Removal of the third bone window did not significantly improve the IMA length that could be harvested.

CONCLUSIONS

The maxillary nerve could be used as a reliable landmark for the exposure of the IMA in the pterygopalatine fossa. With our technique, the IMA could be easily exposed and sufficiently dissected without zygomatic osteotomy and extensive middle fossa floor removal.

Double-barreled IMA-M2 and STA-MCA bypass in severe stenosis of terminal internal carotid artery: three case reports

EC-IC bypasses have been performed to treat complex aneurysms or moyamoya disease or atherosclerotic steno-occlusive disease. We report the three cases that underwent EC-IC revascularization of the IMA-M2 bypass using the radial artery graft concurrently after the STA-MCA anastomosis to prevent potential ischemic damage during the operation and augment more flow in terminal internal carotid artery stenosis. All patients experienced neither perioperative complications nor further events for a 3-month follow-up. The double-barreled IMA-M2 and STA-MCA bypass is a good option for substantial amount of EC-IC revascularization with minimizing ischemic injury and maximizing flow amount in patients with severe hemodynamic compromise.

Imaging methods for surgical revascularization in patients with moyamoya disease: an updated review

Neuroimaging is crucial in moyamoya disease (MMD) for neurosurgeons, during pre-surgical planning and intraoperative navigation not only to maximize the success rate of surgery, but also to minimize postsurgical neurological deficits in patients. This is a review of recent literatures which updates the clinical use of imaging methods in the morphological and hemodynamic assessment of surgical revascularization in patients with MMD. We aimed to assist surgeons in assessing the status of moyamoya vessels, selecting bypass arteries, and monitoring postoperative cerebral perfusion through the latest imaging technology.

Internal maxillary artery to middle cerebral artery bypass for a complex recurrent middle cerebral artery aneurysm: case report and technical considerations

We report the case of a 41-year-old male who presented with an enlarging aneurysm neck one year after clipping. The patient underwent an IMAX-MCA bypass followed by endovascular coil occlusion of the aneurysm neck incorporating an MCA branch origin. To our knowledge, this case represents the first documented IMAX-MCA bypass from a European centre. This case demonstrates that for neurosurgeons experienced in EC-IC bypass surgery, IMAX-MCA bypass is feasible and can be performed safely as long as careful attention is paid to anatomical landmarks and vascular anastomosis principles. CTA-based neuronavigation and micro-Doppler are essential intraoperative tools for identifying the IMAX.

Microsurgical Techniques for Exposing the Internal Maxillary Artery in Cerebral Revascularization Surgery: A Comparative Cadaver Study

BACKGROUND

The internal maxillary artery (IMAX) is currently considered one of the main donor vessels in extracranial-to-intracranial bypass surgeries. Four main techniques for harvesting the IMAX have been described: via the anterior medial infratemporal fossa (AMITF), the middle infratemporal fossa (MITF), the anterior lateral middle fossa (ALMF), and the lateral middle fossa (LMF). The advantages and limitations of these techniques have not yet been systematically evaluated and compared.

METHODS

Twenty-five cadaver specimens were used to evaluate the harvesting technique. The length and the caliber of the targeted IMAX segments, as well as the depth from the operating plane to the IMAX, surgical time, and surgical area of exposure, were analyzed.

RESULTS

The MITF technique provided the greatest operating area of exposure (mean, 3.88 ± 0.97 cm²). The LMF and MITF techniques provided the largest IMAX caliber (mean, 3.1 ± 0.4 mm and 3.0 ± 0.3 mm, respectively). The ALMF technique provided the shallowest operative depth as well as the least time of exposure (21.8 minutes). The MITF technique exposed the longest IMAX segment (mean, 18.8 ± 3.5 mm).

CONCLUSIONS

Advantages of the AMITF and MITF techniques include anatomic simplicity, absence of skull base drilling, and greater discretion in muscle dissection. These properties can simplify the anastomosis procedure compared with the ALMF and LMF techniques. Identification of the IMAX pattern is important before selecting the approach for this bypass operation.

Percutaneous transluminal angioplasty for radial artery graft stenosis after high-flow superficial temporal artery trunk to middle cerebral artery interposition bypass

Due to its higher patency rate, a radial artery graft (RAG) is used as an interposition graft for internal-external high-flow bypass more frequently than a saphenous vein graft (SAG). Nevertheless, there are still a few cases of RAG stenosis after bypass surgery. Unfortunately, these reports do not elaborate on the treatment for RAG stenosis. Here, we report the first case of severe RAG stenosis after high-flow STAt-RA-MCA bypass, which was successfully treated with PTA. We speculated that RAG stenosis is associated with the over-length and kinking of the intracranial segment of the RAG instead of vasospasm. We elaborated on the surgical procedure and treatment experience in this particular case in detail. According to our experience, PTA is a type of surgical procedure that can be considered for treating RAG stenosis after high-flow bypass. As long as the surgical procedure can be performed well according to the distance between the stenosis and the anastomosis and the characteristics of the RA tissue, PTA is able to achieve satisfactory long-term results.