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Combined transmandibular-zygomatic approach and infratemporal craniotomy for intracranial skull base tumors.

Large intracranial skull base tumors remain surgically treacherous lesions. The preauricular transzygomatic infratemporal approach to this area has rapidly gained popularity. This article presents modifications to this approach which improved visualization and access to the infratemporal fossa. The procedure increases visualization, minimizes brain retraction, and results in improved resection and outcome. Reconstruction is rapid and there are minimal functional and cosmetic deficits.

Bone Plates↗

Relief of headache by cranioplasty after skull base surgery.

Headache after skull base surgery can cause profound morbidity in certain patients, resulting in significant impairment of their quality of life. Several methods to prevent postoperative headache have been described, including a modification of the skin/muscle incision replacing the craniotomy bone flap replacing the bone flap and filling in the residual defect with methyl methacrylate, using hydroxyapatite cement (HAC) to fill the craniectomy defect, and wiring hardened methyl methacrylate (MMA) into the defect. Ten patients with severe headache following craniectomy for a posterior fossa lesion underwent cranioplasty with MMA, which was placed exactly within the craniectomy defect and secured rigidly with miniplates and screws. The headache decreased in severity in all patients and resolved completely in 90%. Also, 78% of patients with dizziness improved. The procedure and its effect on headache and dizziness will be described.

Journal Article↗

Chordoma of the skull base: predictors of tumor recurrence.

OBJECT: Chordomas of the skull base are generally regarded as slow-growing tumors; however, approximately 20% of these lesions have been shown to recur as early as 1 year postsurgery. The classic pathological paradigms are poor predictors of outcome, and additional markers are needed to identify patients at risk for early tumor recurrence. In this study the authors describe such a marker. METHODS: In a series of 26 patients with chordomas of the skull base, the authors investigated the relationship between the biological behavior of the tumor, which was determined according to the interval for its recurrence and volume doubling time, and several pathological and molecular features, which included the histological variant, proliferative activity, mutation of p53 protein, expression of human telomerase reverse transcriptase (hTERT) messenger (m)RNA, loss of heterozygosity (LOH), and microsatellite instability. The major finding in this study was that hTERT mRNA expression in chordoma cells identifies those tumors that exhibit unusually fast rates of growth. The expression of hTERT mRNA was frequently associated with mutation of p53 protein, indicating that telomerase dysfunction combines with abnormal p53 function to initiate the unrestrained clonal expansion of the tumor cells. In cases in which the tumor was partially removed, mutation of p53 protein and expression of hTERT mRNA predicted increased doubling time for residual tumor as well as the probability of tumor recurrence. Cell proliferation, as investigated using the Ki-67 method, was significantly related to the tumor doubling time; however, the authors found that the pattern of cell proliferation was not homogeneous throughout the chordoma tissue, and that the proliferative index might change by a factor as high as 8 among different regions of the same tumor. The LOH and microsatellite instability do not seem to affect the prognosis of skull base chordomas. CONCLUSIONS: Reactivation of telomerase in chordomas is a reliable predictor of outcome. The ability to predict the biological behavior of chordomas might have immediate implications in the management of this disease in patients who undergo surgery.

Adult↗

[Combined lateral approach for removal of tumors involving skull base].

Involvement of tumor in the skull base area needs combined approaches for complete removal in some cases. The author reports a combination of infratemporal, supralabyrinthine, translabyrinthine and lateral cervical approaches in 8 cases with benign and malignant tumors involving the skull base from 1989 through 1991. No recurrence was found after 1-2.5 years' followup.

Adult↗

Extended pericranial flap and bone graft reconstruction in anterior skull base surgery.

OBJECTIVES: The objectives of this study was to establish a rationale for repairing large anterior skull base defects with an extended pericranial flap and split calvarial bone graft; to define large anterior skull base defects as those spanning the anterior cranial measuring at least 3.0 x 4.0 cm; and to describe the surgical technique and compare it with alternative strategies. Study design Thirty-four patients underwent anterior craniofacial resection of anterior skull-based tumors of varying histology with reconstruction using an extended pericranial flap and split calvarial bone graft. RESULTS: The survival of the pericranial flap and bone graft was maintained in 33 of 34 patients. There was 1 episode of postoperative cerebrospinal fluid leak, 1 episode of osteomyelitis of the bone graft and an epidural abscess, and 1 episode of asymptomatic pneumocephalus. CONCLUSION: Split calvarial bone graft with an extended pericranial flap is an effective technique for reconstructing large anterior skull base defects.

Bone Transplantation↗

Skull base approach to glomus jugulare.

The skull base approach to the jugular bulb provides a better opportunity to preserve facial nerve function. Specifically, this applies to glomus jugulare tumors. Adequate exposure to remove even an extensive glomus jugulare tumor may be obtained by the skull base approach, working between the VIIth nerve left in its bony sheath and the lateral process of the first cervical vertebra.

Cervical Vertebrae↗

PET-methionine of skull base neuromas and meningiomas.

Eighteen patients with intracranial skull base tumours diagnosed at CT or MR as neuromas or meningiomas were studied with positron emission tomography (PET) using L-(methyl-11C) methionine. Compared with normal cerebellar tissue, the uptake of methionine in the tumours increased more rapidly and reached a higher level, and showed a slow decline after a peak occurring about 5 min after the injection. All the meningiomas exhibited considerably higher accumulation of the tracer compared with the surrounding cerebellar tissue, which made the tumour easy to identify and to demarcate from the surrounding cerebellar tissue, which made the tumour easy to identify and to demarcate from the surrounding structures (tumour to cerebellum ratios 2.62-5.37, mean 3.63). The uptake was homogeneous in all meningiomas, which were all of the syncytial type. The neuromas showed lower contrast against the cerebellum (tumour to cerebellum ratios 1.1-1.87, mean 1.48). Some neuromas displayed an irregular pattern with regions of decreased tracer uptake corresponding to small cystic areas within the neuroma. There was no overlap in methionine uptake between the two tumour groups. The results indicate that PET-methionine may contribute to the evaluation, treatment planning and follow-up of patients with skull base meningiomas and neuromas.

Adult↗

Morphine/ondansetron PCA for postoperative pain, nausea, and vomiting after skull base surgery.

OBJECTIVE: Patients who underwent skull base procedures have been noted to experience appreciable pain. This study examines pain after surgery and the effectiveness of patient controlled analgesia (PCA) with combination morphine ondansetron for analgesia and control of emesis. STUDY DESIGN AND SETTING: A total of 120 skull base surgery patients were randomized to receive placebo, morphine, or morphine ondansetron. Demographic and intraoperative variables were recorded along with pain, nausea, vomiting, and rescue analgesics. Total PCA use, hospital stay, satisfaction, and cost were also compared. RESULTS: Demographically the groups were similar. Pain was elevated with placebo PCA, and this group averaged twice as many analgesic rescues. Total usage time was lower with placebo PCA. Morphine ondansetron PCA had the lowest pain score with highest satisfaction. Nausea and vomiting was similar but female patients had more vomiting regardless of PCA group. CONCLUSIONS AND SIGNIFICANCE: The use of morphine PCA reduced pain and did not appreciably increase nausea or vomiting. The addition of ondansetron produced no real benefit and its PCA use cannot be justified. EBM RATING: A-1b.

Adolescent↗

[Anatomo-radiological classification of meningioma of the posterior skull base].

Between 1972 and february 1993, 140 posterior skull base (clivus and posterior aspect of the petrous bone) meningiomas were seen and treated in our department. Since 1982, we use an anatomo-radiological classification system which is suggested here as a standard classification method for comparison among series of these tumors. Once a meningioma of this region has been discovered the problem is to establish as precisely as possible: its site of origin which will provide evidence of the likely direction of displacement of the blood vessels and nerves of the region. Its exact area of attachment is of prime importance in selecting the best surgical approach. Its size and tumoral extensions which will often dictate the addition of other approaches to allow complete removal. THE SITE OF ATTACHMENT (140 CASES): The posterior skull base may be subdivided into four zones: the clival zone: which comprises the clivus itself and that part of the petrous apex situated medial to the trigeminal impression; the posterior surface of the petrous bone itself subdivided into three roughly equal zones; *an anterior zone (zone A) situated between the trigeminal impression and the anterior lip of the IAM, *a median zone (zone M) from the anterior lip of the IAM to a line immediately posterior to the labyrinthine block, *a posterior zone (zone P) extending from this line to the sigmoïd sinus. In our series, we find meningiomas of the posterior skull base with a discrete site of attachment in the clival zone (10 cases), zone A (29 cases), zone M (31 cases), zone P (19 cases) others have a much wider attachment encompassing two or even three zones, zone A. M (29 cases), zone M. P (15 cases), zone A. M. P (7 cases). THE STAGE OF THE TUMOR: The tumor's base of implantation having been precisely defined, the stage of the tumor is then determined by measuring the distance between the tumor surface and the line of attachment. In our series, 131 tumors were measured: 13 tumors were stage I (tumors with an encroachment into the angle of less than 1 cm), 38 tumors were stage II (1-1.9 cm), 37 tumors were stage III (2-2.9 cm), 43 tumors were stage IV (more than 3 cm). TUMOR EXTENSIONS: These are appreciated on axial, coronal and sagittal images (MRI). Meningiomas of the clivus may extend [8 cases]: very commonly to the petrous apex (zone A) [7 cases], almost always to the tentorium [7 cases], often to the cavernous sinus [5 cases].(ABSTRACT TRUNCATED AT 400 WORDS)

Cranial Fossa, Posterior↗

Computed tomography of the human developing anterior skull base.

The ossification of the anterior skull base, especially the lamina cribrosa, has been studied by computed tomography and histopathology. Sixteen human fetuses, (referred to our laboratory for pathological examination after spontaneous abortion between 18 and 32 weeks of gestation) and three infants, (1, 2 and 6 years of age, respectively) were examined. The cartilaginous preformation of the anterior skull base creates a 'pseudo-defect' on CT in the coronal plane, even with ultra thin sections and high resolution CT. By the age of 6 years of life this 'artefact' is no longer, as the present ossification of the lamina cribrosa is, by that time, complete.

Embryonic and Fetal Development↗

The surgical treatment of skull-base tumors with intracranial extension.

As a discipline, skull-base surgery via the transtemporal route has matured since 1975. Previously considered unresectable, skull-base tumors with intracranial extension can now be successfully removed by means of modification of contemporary exposures with neurosurgical collaboration. Between September 1970 and February 1986, 126 skull-base tumors have been operated on by The Otology Group, P.C. Of these, 49 had intracranial extension. In this article, techniques for tumor removal and dural defect reconstruction are outlined. A single-staged procedure is advised. The advantages of and exceptions to this format are described. Techniques that will prevent postoperative cerebrospinal fluid leakage are highlighted. Results and complications of this surgical series are discussed, and team aspects of this surgery are emphasized.

Adolescent↗

Advanced neuronavigation in skull base tumors and vascular lesions.

OBJECTIVE: The purpose of this study was to describe the usefulness of recent advances of neuronavigational technology in the management of skull base tumors and of vascular lesions, treated via a skull base approach. METHODS: In 16 patients (skull base meningioma n = 9, petrous apex epidermoid n = l, craniopharyngeoma n = 1, giant internal carotid artery aneurysm n = 1, basilar/vertebral artery aneurysm n = 2, brain stem cavernoma n = 2), "advanced" neuronavigation was used. In contrast to "conventional" neuronavigation, the information for the neurosurgeon was enhanced by the intraoperative screen display of 3-dimensional reconstructions of the lesion, vessels, nerves and fiber tracts at risk. The 3-dimensional reconstructions were obtained by preoperative manual or automated segmentation processes. In addition, different imaging modalities (computed tomography [CT] with magnetic resonance imaging [MRI], CT with CT angiography, T (l)- with diffusion-weighted MRI) were fused and shown on the screen. RESULTS: In the cases of tumors, "advanced" neuronavigation facilitated the approach (n = 4), contributed to tailor the approach (n = 2) and helped to identify hidden neurovascular structures (n = 9). In the cases of aneurysms, "advanced" neuronavigation allowed us to reduce the skull base approach to the needs of safe aneurysm clipping (n = 3). In both cases of brain stem cavernoma, "advanced" neuronavigation was deemed useful for definition of the best surgical approach in relation to the pyramidal tract and brain stem nuclei. CONCLUSION: The authors' experiences suggest that neuronavigation, which displays 3-dimensional reconstructions of lesion, vessels, nerves and fiber tracts during surgery and makes use of image fusion techniques, is an important tool in the neurosurgical management of skull base lesions.

Adolescent↗

The fixed combination of collagen with components of fibrin adhesive-a new hemostypic agent in skull base procedures.

CSF leak still is one of the major sources of morbidity after extensive skull base procedures. Of the various standard closure techniques of traumatic or iatrogenic dural defects, none provides a really waterlight, persistent closure. Even the supplementary use of fluid fibrin glue did not substantially improve the rate of postoperative CSF leaks. The application of a collagen sheet covered with a fixed layer of solid components of a fibrin tissue glue (TachoComb(R)) overcomes the major drawbacks of dural sealing in skull base surgery. The dural defects of 58 patients undergoing extensive skull base procedures were sealed with this new hemostyptic agent. The series includes 44 patients undergoing primary surgery, 6 patients with traumatic or iatrogenic tears of venous sinuses, and 8 patients with postoperative leaks after previous skull base procedures in which other sealing methods were previously used. In the group of primary surgery, none of the patients had postoperative CSF leakage or venous rebleeding. One patient developed a delayed pneumatocephalus. All cases of patent CSF fistulas were resolved without any adjuvant therapy. Preliminary experience shows that the good sealing and hemostyptic performance of this new agent will considerably reduce the risk of postoperative CSF leak and infection after skull base procedures.

Journal Article↗

Vasospasm after resection of skull base tumors.

Vasospasm after resection of skull base tumors is a rare complication that often produces serious ischemic sequelae. In four of the authors' recent cases, vasospasm complicated the patient's postoperative course. A review of the literature produced a number of cases that can help determine possible causes of vasospasm after tumor resection, ways to prevent it, and methods to evaluate it when it occurs. The cause appears to be multifactorial and the surgical approach may contribute to the pathogenesis of vasospasm. Physicians must have a high degree of suspicion to detect vasospasm at an early stage of skull base surgery. Cerebral blood flow measurement and transcranial Doppler are useful monitoring tools.

Adenocarcinoma↗

The role of hair shaving in skull base surgery.

OBJECTIVE: We sought to evaluate surgical wound infection rates in patients undergoing skull base surgery without hair removal. METHODS: We undertook a retrospective study of 175 skull base operations performed without hair removal. Anterior operations were conducted via the subcranial approach (n = 120) and lateral or posterior procedures via various approaches (n = 55). Wounds were examined daily during hospitalization and at routine outpatient follow-up (8 to 45 months) and classified according to the Center for Disease Control and Prevention guidelines. RESULTS: The overall surgical wound infection rate was 1.1% (2 of 175): 0.8% (1 of 120) for anterior and 1.8% (1 of 55) for lateral or posterior procedures. It was similar for clean operations (lateral and posterior) and clean-contaminated (anterior) procedures and was less than or similar to the rates reported for skull base procedures with hair removal. No wound infection occurred among the infected (trauma, fungal infections, and brain abscess) patients. CONCLUSIONS: Skull base surgery without hair removal is safe and not associated with increased risk of wound infection. The method may prevent additional psychologic stress, promote restoration of the patient's self-image, and accelerate his or her return to normal life.

Adolescent↗

Microvascular free tissue transfer in reconstructing skull base defects: lessons learned.

OBJECTIVE: To demonstrate the effectiveness of microvascular free tissue transfer in reconstructing complex skull base defects. STUDY DESIGN: Retrospective chart review. METHODS: A retrospective chart review was conducted identifying patients with anterior or lateral skull base defects, or both, who underwent microvascular free flap reconstruction. Appropriate demographic, pathological, and preoperative and postoperative clinical data were collected and analyzed. RESULTS: Thirty-five patients with skull base defects were identified, including 8 women (Mean age, 43.9 y; age range, 28-75 y) and 27 men (mean age, 57.9 y; age range, 19-85 y). Defects were secondary to trauma in two cases, whereas the remaining 33 cases were secondary to ablative procedures for a variety of malignant tumors, of which squamous cell carcinoma was the most common (n = 18). The average defect surface area was 89.3 cm(2), and 36 free flaps were used. The most commonly used flap was the rectus myocutaneous (n = 20); however, six different flap types were employed, including three radial forearm fascial flaps. In all, there were seven flap-related complications and there was one total flap loss. A total of 43 postoperative complications occurred in 23 patients, with the most common complications being grouped as intracranial (n = 10), orbital (n = 9), and cardiac (n = 9). The perioperative mortality rate was 5.7%, and the average hospital stay was 13.5 days (range, 7-37 d). CONCLUSIONS: The use of microvascular free tissue transfer for reconstruction of complex skull base defects has proven highly successful in the large series presented in the current study. The versatility and reliability of free flaps for such reconstruction are discussed, and helpful hints are given to minimize the complication rate.

Adult↗

Endoscopic endonasal approaches to anterior skull base defects in pediatric patients.

INTRODUCTION: We studied 12 pediatric patients with congenital or acquired anterior skull base defects. All subjects underwent surgery owing to progressive symptoms. The endoscopic endonasal approach is a new method in the treatment of this pathology in children. MATERIALS AND METHODS: Twelve children had surgery to correct anterior skull base defects: seven patients with a spontaneous anterior basal meningoencephalocele and five with posttraumatic cerebrospinal fluid (CSF) leakage. The defects were repaired using the endoscopic endonasal approach, which combined with the fluorescein diagnostic test, detects the exact location of the skull base defect. Different closure techniques were used to obtain a permanent graft, depending on the type, location, and size of the defect. An intraoperative fluorescein test confirmed the absence of CSF leakage after surgery. RESULTS: The follow-up period ranged from 3 to 72 months. Symptoms resolved in all patients after surgery and none of them experienced complications or recurrence of CSF leakage. Postoperative magnetic resonance scans showed that the defect had successfully been repaired in all patients. DISCUSSION: The surgical treatment of skull base defects in children reduces life-threatening risks, which include infections, CSF leaks, and enlargement or trauma of the sac. The endoscopic technique minimizes surgical scars and has little impact on brain tissue. The endoscopic endonasal approach to the anterior skull base helps to preserve the physiology of the nose and sinuses and reduces the impact on the still developing splanchnocranium in pediatric patients. It ensures a definitive repair of the defect and requires a very short inpatient period.

Adolescent↗