Preservation Of Lower Cranial Nerves Research Articles

Jugular Foramen Paragangliomas.

Paragangliomas are the most common tumors at jugular foramen and pose a great surgical challenge. Careful clinical history and physical examination must be performed to adequately evaluate neurological deficits and its chronologic evolution, also to delineate an overview of the patient performance status. Complete imaging evaluation including MRI and CT scans should be performed, and angiography is a must to depict tumor blood supply and sigmoid sinus/internal jugular vein patency. Screening for multifocal paragangliomas is advisable, with a whole-body imaging. Laboratory investigation of endocrine function of the tumor is necessary, and adrenergic tumors may be associated with synchronous lesions. Preoperative prepare with alpha-blockage is advisable in norepinephrine/epinephrine-secreting tumors; however, it is not advisable in exclusively dopamine-secreting neoplasms. Best surgical candidates are young otherwise healthy patients with smaller lesions; however, treatment should be individualized each case. Variations of infratemporal fossa approach are employed depending on extensions of the mass. Regarding facial nerve management, we avoid to expose or reroute it if there is preoperative function preservation and prefer to work around facial canal in way of a fallopian bridge technique. If there is preoperative facial nerve compromise, the mastoid segment of the nerve is exposed, and it may be grafted if invaded or just decompressed. A key point is to preserve the anteromedial wall of internal jugular vein if there is preoperative preservation of lower cranial nerves. Careful multilayer closure is essential to avoid at most cerebrospinal fluid leakage. Residual tumors may be reoperated if growing and presenting mass effect or be candidate for adjuvant stereotactic radiosurgery.

Technique Nuances for Functional Preservation of Lower Cranial Nerves during Surgical Management of Ventral Foramen Magnum Meningiomas Via a Dorsal Lateral Approach

This study established novel technique nuances in surgery for ventral foramen magnum meningiomas (vFMMs) via a dorsal lateral approach. From July 2012 to July 2019, 37 patients with vFMMs underwent tumor resection surgery and were operated on with a dorsal lateral approach. Two safe zones were selected as the entrance of the surgical corridor. Safe zone I was located between the dural attachment of the first dental ligament (FDL) and the branches of C1; safe zone II lay between the dural attachment of the FDL and the jugular foramen. The tumor was debulked first through safe zone I and then through safe zone II. The tumor was removed through a trajectory from the caudal to cephalad to allow tumor debulking from below and downward delivery, away from the brainstem and lower cranial nerves. Thirty-three patients underwent gross total resection, and 4 patients underwent subtotal resection. Four patients transiently required a nasogastric feeding tube. All patients recovered within 3 months postoperatively. Three patients (8.1%) developed permanent mild hoarseness and dysphagia as a result of postoperative damage of cranial nerves IX and X. One patient underwent tracheotomy. No patient experienced tumor recurrence during the follow-up period. We established a minimal retraction principle, in which the selection of 2 safe zones as the entrance of the surgical corridor, tumor removal from the inferior to superior direction, and debulking followed by devascularization were the key elements to implement the minimal retraction principle in vFMM surgery.

Temporal paragangliomas

Temporal paragangliomas (PGL) are usually limited to the paraganglionar system with a sporadic or familial origin. Familial PGL have recently been shown to be associated with germline alterations in SDH group of genes, and occasionally are associated with a variety of genetic multisystemic disorders (von Hippel-Lindau disease, multiple endocrine neoplasia type 2 and neurofibromatosis type 1). Temporal bone PGL are normally located in the region of the jugular foramen and on the promontory along the Jacobson nerve. Occasionally, vagal PGL may reach the jugular foramen and behave as jugular PGL. Treatment of temporal PGL must be based on the biological behavior of the tumour, age and medical condition of the patient, location and size of the PGL, and potential for treatment induced morbidity. The main treatment modalities for PGL are surgery and radiation therapy. Patients with large temporal PGL whose resection would result in potentially disabling morbidity are often selected for radiation therapy or wait and scan policy. Small tympanic PGL where resection may be carried out with a low morbidity risk can be removed through an endomeatal tympanotomy. Jugular PGL limited to the infralabyrinthine region involving only the vertical segment of the ICA, can benefit of an extended facial recess approach, which allows a postoperative normal hearing and facial nerve function. For more extensive disease in the middle ear or around the ICA, external auditory canal preservation is not possible and some kind of facial nerve mobilization is required. Preservation of lower cranial nerves is facilitated by intrabulbar dissection, previous extradural ligation of the sigmoid sinus. Management of large intracranial involvement is controversial, although most authors advocate resection of the tumour in a single stage. Surgical control of the tumour can be expected in 70-85% of the patients and is clearly dependent on the tumour stage. Tumour size determines success in hearing and lower cranial nerves preservation.

Tumors of the Jugular Foramen: Diagnosis and Management

Jugular foramen tumors are rare cranial base lesions that present diagnostic and management difficulties. With the availability of new diagnostic procedures these tumors have been more precisely studied and questions of whether, when, and how these lesions should be treated often arise. Data from 106 consecutive patients surgically treated in the past 17 years were retrospectively analyzed to identify surgical outcomes. The tumors were approached by a multidisciplinary team composed of neurosurgeons, ear, nose, and throat surgeons, and neuroradiologists. Hypervascular lesions were embolized 3 to 5 days before surgery. The same surgical technique was used to resect all tumors. The surgical defect was covered with vascularized myofascial flaps. The internal carotid artery was infiltrated in two patients, and a saphenous graft bypass was carried out before removal of the lesions. The facial nerve was reconstructed with nerve grafts (great auricular nerve) or XII/VII anastomosis in five cases. Postoperative radiotherapy was carried out for malignant and invasive tumors. Paragangliomas were the most frequent lesions, followed by schwannomas and meningiomas. Complete excision was possible in 89% of benign tumors and 80% of paragangliomas. Lower cranial nerve deficit was the most frequent complication (10 patients, 9.4%), transient in 4 patients. Facial and cochlear nerve paralysis occurred in 8 patients (7.5%). The function of the facial nerve recovered spontaneously in 3 patients. Four patients (3.7%) developed postoperative cerebrospinal fluid leakage. Four patients (3.7%) died after surgery. Radical removal of benign jugular foramen tumors is the treatment of choice and may be curative. Large lesions can be radically excised in one surgical procedure with preservation of lower cranial nerves. Cranial base reconstruction with vascularized myofascial flaps reduces the incidence of postoperative cerebrospinal fluid leakage. Damage of the lower cranial nerves is the most serious surgical complication.