Extracranial-intracranial bypass for reconstruction of internal carotid artery in the management of head and neck cancer

Resection of the internal carotid artery in selected patients affected by cancer of the skull base

Invasion of the internal carotid artery (ICA) has been historically considered a criterion of non-resectability of skull base cancer (SBC). Patients affected by SBC who underwent surgery including resection of ICA at two tertiary institutions were included. Demographics, oncologic, and surgical information, complications, and survival outcomes were retrospectively reviewed. Survival outcomes were calculated. Ten patients were included. Three surgical approaches (transnasal endoscopic, transorbital, and transpetrosal) were employed to resect the invaded/abutted tract(s) of the ICA. All patients underwent ICA temporary balloon occlusion test. In two patients, an extracranial-to-intracranial arterial bypass was harvested. Major neuromorbidity was observed in two patients. Perioperative mortality of the series was 10.0%. Mean overall survival was 27.2 months, with 2-year overall and progression-free survival rate of 88.9%. ICA resection is feasible as part of the ablation performed for very advanced SBCs. Survival outcomes are acceptable in adequately selected patients.

EC-IC bypass for cerebral revascularization following skull base tumor resection: Current practices and innovations

Complex skull base tumors can involve critical vessels of the head and neck. To achieve a gross total resection, vessel sacrifice may be necessary. In cases where vessel sacrifice will cause symptomatic cerebral ischemia, surgical revascularization is required. The purpose of this paper is to review cerebral revascularization for skull base tumors, the indications for these procedures, outcomes, advances, and future directions.

Indications and Outcomes of Prophylactic and Therapeutic Extracranial-to-intracranial Arterial Bypass for Cerebral Revascularization

Background:

Extracranial-to-intracranial (EC-IC) arterial bypass is a technically demanding procedure used to treat complex cerebral artery diseases. The indications, proper surgical techniques, and outcomes of this procedure have been under debate over the recent decades.

Methods:

Between January 2004 and December 2012, 28 patients, including patients with cerebral artery occlusion, intracranial aneurysm, cranial base tumor, and Moyamoya disease, underwent EC-IC bypass. Patients’ records were retrospectively reviewed for demography, indications, complications, high-flow versus low-flow bypass, patency rate of bypass, and neurological outcome. The patients were sorted into prophylactic (n = 16) and therapeutic (n = 12) groups based on the preoperative presentation of their neurological symptoms. Follow-up evaluation was performed at a mean of 32.7 ± 24.3 months.

Results:

The overall patency rate of bypass was 100%, the postoperative stroke rate was zero, and the surgical complication rate was 14.3%. There was no significant difference in the bypass patency rate between the 2 groups or between the high-flow and low-flow bypass patients. Patients who underwent prophylactic bypass had minimal surgical and total complications (P = 0.03 and P < 0.01, respectively) and a better neurological outcome. Surgical complications were more common in patients who underwent therapeutic bypass (25%).

Conclusions:

The collaboration of neurosurgeons and plastic surgeons in performing EC-IC bypass can result in excellent outcomes with a high bypass patency rate and few complications, particularly for prophylactic EC-IC bypass.

Viability of anastomoses with coupler in extra-intracranial bypass: cadaveric study

BACKGROUND

The time required to perform an anastomosis in extra-intracranial bypass is approximately 20 to 60 minutes. The search for alternative methods to reduce the ischemic time remains vital.

OBJECTIVE

To evaluate Coupler anastomosis for extra-intracranial bypass in cadavers.

METHODS

In 8 fresh adult cadavers, the saphenous vein and radial artery were used as donor vessels. The superficial temporal and the extracranial internal and external carotid arteries were dissected. A wide craniotomy with a sylvian fissure opening was performed, exposing the middle cerebral and supraclinoid internal carotid arteries. The Coupler devices were tested in all 8 cadavers. The diameter of the donor and recipient vessels as well as the time required to perform the anastomosis were measured. Bypass permeability was evaluated by injecting saline solution under pressure, checking for leaks.

RESULTS

The anastomoses were successfully performed in all specimens. The size of the head of the fitting Coupler required the performance of a wide craniotomy (6 × 6 cm) and a wide opening of the sylvian fissure. The time required to perform each anastomosis ranged from 4 to 7 minutes, being easier with the radial artery than with the saphenous vein.

CONCLUSION

Coupler devices are helpful to perform the anastomoses, because they significantly reduce ischemia time. Their use is easier at the M1 segment, just before the bifurcation and after takeoff of the lenticulostriate arteries, and in the M2 segment. It would be advisable to have a smaller coupling system, allowing maneuverability in the deeper areas where space is limited.

A novel strategy to engineer small-diameter vascular grafts from marrow-derived mesenchymal stem cells

Tissue-engineered blood vessels have mainly relied on endothelial cells (ECs), smooth muscle cells (SMCs), and biocompatible materials. However, long-term results have revealed several material-related failures, such as stenosis, thromboembolization, and the risk of infection. Furthermore, SMCs from elderly persons have reduced capacity in proliferation and collagen production. Mesenchymal stem cells (MSCs) have the ability to differentiate into multiple cell lineages, including osteoblasts, chondrocytes, ECs, and SMCs. In the current experiment, rabbit MSCs were cultured to form a cell sheet. A tissue-engineered vascular graft (TEVG) was fabricated by rolling the MSC sheet around a mandrel. The TEVG was implanted into a defect of the common carotid artery after it was examined macroscopically and microscopically. Hematoxylin and eosin staining showed that cell sheet was composed of five to seven layers of cells with the thickness of 40-50 µm. Results from the adhesion assay revealed that MSCs had similar antiplatelet adhesion property to ECs. Histological analysis of TEVGs showed that the layers of the cell sheet had fully fused in vitro. After implantation, TEVGs had excellent patency and integrated well with the native vessel. The structure of the TEVGs was similar to that of the native artery 4 weeks after implantation. Electron microscopy showed that the implanted TEVGs endothelialized. These results indicated that a completely biological TEVG could be assembled with autologous MSCs. These TEVGs are useful for revascularization in humans, which would reduce the occurrence of complications caused by foreign materials.

The plastic surgeon's role in extracranial-to-intracranial bypass using a reverse great saphenous vein graft

BACKGROUND

Extracranial-to-intracranial bypass is used for flow replacement and diversion that prevent the serious complications associated with sudden ligation of the middle cerebral artery for treatment of complex tumors or aneurysms. Extracranial-to-intracranial bypass is a demanding procedure that requires experience in advanced microsurgical techniques. In this article, the authors review the first report of an extracranial-to-intracranial bypass performed by a plastic surgeon with emphasis on indications for microsurgical involvement in neurosurgical practice and on description of the surgical technique.

METHODS

Between April of 2004 and October of 2006, three extracranial-to-intracranial bypass cases were performed including one for a complex aneurysm rupture and two for resections of cranial base tumors. In every case, the intracranial approach was used by the neurosurgeon. The bypass was performed by interposing a reverse great saphenous vein graft between the superficial temporal artery, in end-to-end anastomosis, and the second segment of the middle cerebral artery, in end-to-side anastomosis.

RESULTS

In each case, postoperative cerebral angiography demonstrated complete patency of the extracranial-to-intracranial bypass. Neither of the two surviving patients at a mean follow-up of 13 months had deterioration of neurologic function, postoperative stroke, or surgery-related death. One of the patients was dead before the 6-month follow-up.

CONCLUSIONS

The reverse great saphenous vein graft is a good option for extracranial-to-intracranial bypass, with the advantages of high-flow graft, wide lumen, adequate length, easy harvest, and minimal donor-site morbidity. The plastic surgery/neurosurgery alliance allows scope for improved outcomes in complex neurosurgical cases and continues to push the frontiers of reconstructive microsurgery.

Exposure of the Distal Cervical Segment of the Internal Carotid Artery Using the Trans-spinosum Corridor: Cadaveric Study of Surgical Anatomy

Background:

Exposure of the most distal portion of the cervical segment of the internal carotid artery (ICA) is technically challenging. Previous descriptions of cranial base approaches to expose this segment noted facial nerve manipulation, resection of the glenoid fossa, and significant retraction or resection of the condyle. We propose a new approach using the frontotemporal orbitozygomatic approach to expose the distal portion of the cervical segment of the ICA via the trans-spinosum corridor.

Methods:

Six formalin-fixed injected heads were used for cadaveric dissection. Two blocs containing the carotid canal and surrounding region were used for histological examination.

Results:

The ICA lies immediately medial to the vaginal process. The carotid sheath attaches laterally to the vaginal process. With use of the trans-spinosum corridor, the surgeon's line of sight courses in front of the temporomandibular joint, through the foramen spinosum, spine of the sphenoid, and vaginal process. Removal of the vaginal process exposes the vertical portion of the petrous segment of the ICA. The loose connective tissue space between the adventitia and the carotid sheath is easily entered from above. Incision of the carotid sheath exposes the ICA without disruption of the temporomandibular joint.

Conclusion:

Control of the cervical segment of the ICA can be critical when dealing with cranial base tumors that invade or surround the petrous segment of the ICA. This novel technique through the trans-spinosum corridor can effectively expose the distal portion of the cervical segment of the ICA without causing manipulation of the facial nerve and while maintaining the integrity of the temporomandibular joint.

Revision Glomus Tumor Surgery

The infratemporal fossa approach type A is the best way to deal with recurrent tympano-jugular paragangliomas because facial nerve rerouting is fundamental to reaching the area of the internal carotid artery, where recurrence is likely to occur. Preservation of lower cranial nerve function is not feasible when there is tumor infiltration of the medial wall of the jugular bulb; any attempt at nerve dissection increases the risk of leaving some tumor remnants. Correct management of the internal carotid artery, including preoperative stent insertion or permanent preoperative balloon occlusion, is usually a fundamental step when dealing with these highly vascularized lesions. Because of the tumor tendency to infiltrate the bony structures, aggressive drilling of the temporal bone is also advised, especially at the level of the petrous apex. Patients affected by uncontrolled recurrences still die of this disease.

Revascularization for complex skull base tumors

We discuss revascularization techniques for complex skull base lesions utilizing high-flow arterial bypass. At present, the radial artery is the donor graft utilized in most circumstances at our institution. The knowledge of revascularization techniques is very important to achieve radical resection in lesions where arterial compromise is documented.

Recommendations for Comprehensive Stroke Centers

Background and Purpose— To develop recommendations for the establishment of comprehensive stroke centers capable of delivering the full spectrum of care to seriously ill patients with stroke and cerebrovascular disease. Recommendations were developed by members of the Brain Attack Coalition (BAC), which is a multidisciplinary group of members from major professional organizations involved with the care of patients with stroke and cerebrovascular disease.

Summary of Review— A comprehensive literature search was conducted from 1966 through December 2004 using Medline and Pub Med. Articles with information about clinical trials, meta-analyses, care guidelines, scientific guidelines, and other relevant clinical and research reports were examined and graded using established evidence-based medicine approaches for therapeutic and diagnostic modalities. Evidence was also obtained from a questionnaire survey sent to leaders in cerebrovascular disease. Members of BAC reviewed literature related to their field and graded the scientific evidence on the various diagnostic and treatment modalities for stroke. Input was obtained from the organizations represented by BAC. BAC met on several occasions to review each specific recommendation and reach a consensus about its importance in light of other medical, logistical, and financial factors.

Conclusions— There are a number of key areas supported by evidence-based medicine that are important for a comprehensive stroke center and its ability to deliver the wide variety of specialized care needed by patients with serious cerebrovascular disease. These areas include: (1) health care personnel with specific expertise in a number of disciplines, including neurosurgery and vascular neurology; (2) advanced neuroimaging capabilities such as MRI and various types of cerebral angiography; (3) surgical and endovascular techniques, including clipping and coiling of intracranial aneurysms, carotid endarterectomy, and intra-arterial thrombolytic therapy; and (4) other specific infrastructure and programmatic elements such as an intensive care unit and a stroke registry. Integration of these elements into a coordinated hospital-based program or system is likely to improve outcomes of patients with strokes and complex cerebrovascular disease who require the services of a comprehensive stroke center.