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At least 19 recordsLinked to original sources

Cystic schwannoma of the sphenoid sinus and skull base.

Skull base and intracranial cystic schwannomas are rare tumors. To our knowledge, a cystic schwannoma involving the sphenoid sinus has not been previously reported. The location and fluid-filled nature of the lesion resulted in an erroneous preliminary diagnosis of a destructive sphenoid sinus mucocele. Endoscopic biopsy and decompression established the correct diagnosis and reversed a progressive visual loss until definitive surgical removal of the lesion was accomplished. Diagnostic evaluation, histologic findings and management strategies are discussed.

Humans↗

Skull base surgery for benign skull base tumors.

The use of skull base techniques in the treatment of benign skull base tumors has allowed access to areas of the brain once considered inaccessible. The most common benign skull base tumors encountered in neurosurgical practice are benign meningiomas, schwannomas, and glomus jugulare tumors. Gross total resection of these lesions gives patients the best possible chance of a cure. In this paper, we review the rationale for the use of skull base surgery techniques for benign skull base tumors.

Humans↗

[Anatomical landmarks of skull base and safety of the skull base surgery].

OBJECTIVE: In order to improve the safety of skull base surgery and to completely resect the skull base tumors, the anatomical landmarks of skull base were studied. METHODS: 29 cases of skull base surgery were performed between 1992 and 2002, and their clinical data were retrospectively analysed. The anatomical landmarks of cranial base, such as comb, pterygoid process, spine of temporal bone, styloid process, and internal caroid artery, were analysed in preoperative diagnosis and operative treatment of various kinds of skull base tumors. RESULTS: In the early stages, because of lacking the knowledge of anatomical landmarks of the skull base, the surgery lasted longer, part of skull base tumors remained and operative blood lose was much more than that in later stage. In the later stage, no operative death and severe complications were found in 26 cases which underwent various kinds of skull base surgery. The survival rates at 3 and 5 years were 72.2% and 35.7% respectively for malignant tumors. CONCLUSIONS: Comb, pterygoid process, spine of temporal bone, styloid process, internal caroid artery and their adjacent structures were important anatomical landmarks for operative treatment of anterior, middle and lateral cranial base tumors. It was important to know the anatomical landmarks to ensure the safety of the skull base surgery.

Adolescent↗

Role of brachytherapy in the management of the skull base meningioma. Treatment of skull base meningiomas.

BACKGROUND: The treatment of primary and recurrent skull base meningiomas presents a formidable surgical problem. METHODS: Fifteen patients with primary and recurrent skull base meningiomas were treated by means of interstitial irradiation with iodine 125 (125I) seed implantation. The physical characteristics of 125I enabled the authors to administer a minimum tumor dose ranging from 100 to 500 Gy at a low dose rate of 0.05-0.25 Gy per hour. RESULTS: All 15 patients are alive at a median follow-up of 29 months. Of the 15 patients, 2 with calcification and 2 without calcification achieved only partial responses. The remaining 11 patients achieved a complete response. No early or late complications were observed. CONCLUSIONS: From these data, the authors conclude that interstitial irradiation with 125I seeds is an effective, safe, and simple method in the treatment of both recurrent and primary skull base meningiomas.

Adult↗

Pituitary adenoma invading the skull base--a strategy for skull base surgery.

A strategy for surgical management, including the approach and preoperative evaluation, of pituitary adenoma invading the skull base is described. Preoperative evaluation requires a balloon occlusion test of the internal carotid artery (ICA) to determine tolerance to occlusion. Failure to tolerate occlusion indicates administration of brain protective agents and/or a bypass procedure before tumor removal. The transsphenoidal, pterional, orbitofrontomalar, and infratemporal fossa approaches are all suitable for various tumor locations. A combined orbitofrontomalar and extended frontal approach allows removal of tumor with extensive invasion and is suitable for bypass procedures. Preoperative evaluation of ICA occlusion can prevent development of hemodynamic stroke. We treated five patients with pituitary adenoma invading the skull base, including two primary and three recurrent cases. All symptoms improved, but temporary oculomotor nerve disturbance occurred in three patients and anosmia in one. Reoperations for recurrent pituitary adenomas were effective in reversing the symptoms. No hemodynamic stroke was seen postoperatively. These tumors, except for drug-responsive cases, are indicated for skull base surgery.

Adenoma↗

The contribution of high-resolution multiplanar reformats of the skull base to the detection of skull-base fractures.

AIM: To investigate the contribution of routine review of submillimetric multiplanar reformats to the diagnosis of skull-base fractures. METHODS: A prospective analysis was performed of 407 cases referred over a 6-month period for CT of the skull following cranial trauma. The reformatted 5-mm axial sections and subsequently the high-resolution multiplanar reformats (HRMPRs) were viewed on an ADW 4.1 workstation using bone windows and algorithm. All skull-base fractures and related features, recorded by the consensus of two radiologists, were classified as anatomically significant or non-significant on the basis of eight criteria. The clinical features of skull-base injury and any subsequent treatment were noted in all cases of skull-base fracture. RESULTS: HRMPRs detected 80 separate skull-base fractures in 36/407 cases. Of these 80 fractures, 57 were visible on 5-mm axial sections. In 8 of the 36 cases, the significant anatomical features were only evident on review of the HRMPRs. In 6 of the 36 cases, none of the skull-base fractures was visible on 5-mm sections, but these individuals had only minor associated clinical features and no therapeutic requirements. Review of HRMPRs could have been confined to patients with skull-base fractures, abnormal intracranial and extracranial air collections or opacified mastoid air cells revealed by 5-mm axial sections. This policy would have led to the detection of 79/80 (99%) of skull-base fractures and all significant anatomical features. CONCLUSION: The 5-mm axial sections demonstrated 71% of skull-base fractures and 78% of skull-base fractures with significant anatomical features, using HRMPRs as a gold standard. There were no significant clinical sequelae at short-term follow-up of those fractures only evident on HRMPRs.

Adolescent↗

A surgical method for treating anterior skull base injuries.

Skull base surgery was performed on 18 patients with anterior skull base injuries. The operative technique consisted of opening the operative field in the anterior skull base via a coronal incision and a frontal craniotomy, debridement of the anterior skull base including the injured dura mater, performing drainage from the anterior skull base to the nasal cavity by ethmoidectomy, and reconstructing the resulting dural and anterior skull base defect using bilateral temporal musculo-pericranial flaps and a bone graft. Seventeen of the 18 patients recovered without any complications, although epidural abscesses in the anterior skull base had been present in four patients at the time of the operation. Only one patient developed an epidural abscess in the anterior skull base after the operation. None of the patients developed any other complications including meningitis, recurrent liquorrhoea or cerebral herniation. Satisfactory aesthetic results were achieved in 16 of the 18 patients. In one patient, uneven deformity of the forehead, which was caused by the partial sequestration of the frontal bone due to postoperative infection, was observed. In another patient, a depressed deformity of the forehead, which was caused by the partial loss of the frontalis muscle following the use of the frontal musculo-pericranial flap instead of a temporal musculo-pericranial flap, was observed. Anterior skull base reconstruction using bilateral temporal musculo-pericranial flaps provides excellent results in terms of patient recovery and aesthetics.

Adolescent↗

A high-resolution MRI study of linear growth of the human fetal skull base.

The skull base, otherwise referred to as the basicranium or cranial base, plays a key role in the process of skull development, providing both support for the brain and an architectural component of the craniofacial complex. Consequently, the fetal skull base has been the focus of numerous studies employing various methods, including sectioning, plain radiography and CT. This paper investigates high-resolution (hr) MRI as an alternative method for looking at and quantifying the fetal skull base. The evaluation tests two basic hypotheses drawn from previous studies. These suggest that the anterior segment of the midline skull base grows more rapidly than the posterior segment and that the width of the posterior cranial fossa increases disproportionately in relation to its length. I imaged 42 formalin preserved human fetuses from museum collections with hrMRI. The T2-weighted image voxels were significantly smaller than those acquired with conventional clinical MRI. Landmarks of the fetal skull base were identified on reformatted axial and sagittal images. Bivariate plots revealed that the growth rate of the anterior skull base is almost twice that of the posterior skull base and that increases in the width of the posterior cranial fossa exceed those in its length. These findings confirm those of previous investigations and show that hrMRI offers a way forward in noninvasive quantification of fetal morphology.

Cranial Fossa, Posterior↗

Secondary craniofacial problems following skull base surgery.

Skull base wounds remain the most challenging that a skull base surgeon faces because of the unique and unforgiving requirements of the intracranial compartment. To successfully reconstruct these defects after complex exposure and radical resection around vital structures, a most conservative approach must be taken (i.e., one must choose the option that has the greatest chance to be successful, even if it means taking the extra time and effort of doing a free tissue transfer). Indeed, one can take no short cuts if the skull base would be left with a tenuous repair. Close postoperative surveillance of the patient for complications and maximal medical management is essential. Because of the difficulty of examining the hidden skull base wound postoperatively, surgeons must have a low threshold for re-exploration if a complication is suspected. As the first decade of the multidisciplinary skull base team approach passes, and long-term results are being assessed, the question of "is it worth it?" is fair. The reported series are showing increased survival rates and decreased complication rates. Therefore, the answer would appear to be "yes". The question is best answered, however, by the individual patient who previously had no hope for treatment of his or her deep-seated skull base tumor.

Adult↗

Reconstruction of skull base defects after minimally invasive endoscopic resection of anterior skull base neoplasms.

BACKGROUND: The endoscopic resection of the cribriform plate during minimally invasive endoscopic resection (MIER) of the anterior skull base neoplasms may result in large anterior skull base defects. The objective of this study is to describe techniques for the management of skull base defects after MIER. METHODS: Retrospective analysis was performed on patients undergoing MIER and skull base reconstruction between April 2000 and August 2005. RESULTS: Fourteen patients underwent endoscopic resection of anterior skull base tumors and reconstruction during the study period. The mean age was 57.4 years (range, 26-84 years). The sex distribution was eight men and six women. The specific indications for resection included 11 malignant and 3 benign neoplasms. Ten patients received adjuvant therapy, and in two instances this occurred before surgery. In all instances, the dura was exposed; however, only 10 cerebrospinal fluid (CSF) leaks were encountered intraoperatively. Reconstruction of the skull base was successfully performed, most commonly in a multilayer fashion, using an array of materials including cartilage, fat, acellular dermal graft, and mucosal free grafts. Lumbar drain placement was used in seven cases for an average of 5.6 days. No postoperative CSF leaks occurred. The mean follow-up was 18.0 months (range, 1-56 months). CONCLUSION: This report describes methods for the reconstruction of the skull base after MIER. Reconstitution of the skull base barrier can be achieved through application of principles for surgical repair of CSF rhinorrhea.

Adult↗

Imaging of the skull base.

Skull-base imaging has been a key factor in the advancement of skull-base surgery. The analysis of MR imaging or CT of the skull base emphasizes important landmarks, which are key to surgical planning. Although the definitive diagnosis usually is done by biopsy, the radiologist can limit the list of possibilities of the identity of a skull base lesion. The apparent site of origin is a key factor. Separation of cystic abnormalities from more solid enhancing abnormalities also is critical.

Biopsy↗

Endoscopic endonasal skull base surgery: Part 1--The midline anterior fossa skull base.

OBJECTIVE: An endonasal endoscopic surgery to the anterior fossa skull base was developed in cadaver dissection as a minimally invasive surgical technique and, subsequently, used in patient treatment. METHODS: Six cadaver head specimens were used. Ideal head positioning and various surgical routes were studied. To estimate the extent of surgical exposure provided by this technique, the width of the exposed anterior cranial fossa was measured between the medial margin of the orbits, the optic nerves and the carotid arteries. Three demonstrative patient cases are presented. RESULTS: Ideal head positioning was discovered to be at 15-degree extension of the forehead-chin line. Paraseptal, middle meatal and middle turbinectomy approaches were developed. The average width between the medial orbits was measured to be 24 mm (range 22-29 mm) at the crista galli level, 27 mm (range 24-30 mm) at the planum sphenoidale, 18 mm (range 15-22 mm) between the optic nerves, and 17 mm (range 13-21 mm) between the rostral carotid siphons. This technique, when it was applied in patient care, proved to be minimally invasive. CONCLUSIONS: This endoscopic endonasal approach provided a direct "short-cut" access to the midline anterior fossa skull base. This technique can be used for the surgical treatment of cerebrospinal fluid (CSF) leak, meningiomas, craniopharyngiomas, pituitary adenomas, and other midline intracranial anterior skull base lesions. This is the first report in the English literature describing endonasal endoscopy for the surgical treatment of primary intracranial anterior fossa skull base lesions.

Adult↗

[Modified transcranial approach to resect tumor around the anterior skull base and double tissue flap to reconstruct the anterior skull base].

OBJECTIVE: To explore better approach of resecting tumor around the anterior skull base and reconstructing the anterior skull base. METHODS: In November 2004, a 49-years-old male patient with intracranial recrudescent adenoid cystic carcinoma in the anterior cranial fossa was treated using modified transcranial approach. Neurosurgeon and rhinolaryngologist cooperated to excise the tumour completely, and to reconstruct anterior skull base using the pedicle periosteum temporal musculofascial flap (15 cm x 10 cm) and the pedicle flap of aponeurosis of occipitofron tails muscle and muscular fasciae (10 cm x 6 cm). RESULTS: After operation, the wound healed by first intention. Complication, such as infection and cerebrospinal rhinorrhea, did not occur. The patient was discharged 10 days after operation, and was followed up for 8 months, no local recurrence were investigated and no scar formed over the face. CONCLUSION: The modified transcranial approach is a relatively novel exposure that enables the skilled cranial base surgeon to safely resect many malignant lesions previously and to reconstruct the defect of anterior skull base together.

Craniotomy↗

Reconstruction of skull base defects.

Skull base defects are classified into three regions based on the anatomic location and growth pattern of the tumors. The goals of reconstruction are based on the necessity of obtaining a watertight seal between the cranial contents and the aerodigestive tract, thereby avoiding any communication, which could result in ascending meningitis. Pedicled flap options have largely been replaced by free tissue transfers, with the exception of small Zone I defects that can still be safely reconstructed with local pedicle flaps. The rectus abdominis free muscle flap has become the workhorse of skull base reconstruction, resulting in a decrease in the complication rate following these procedures. Various other factors have significantly improved the prognosis of patients who require tumor ablation involving the skull base.

Humans↗

Surgical reconstruction after extensive skull base surgery.

Skull base surgery is a rapidly expanding surgical subspecialty bringing together the sophisticated surgical skills of the neurotologist-head and neck surgeon and the neurosurgeon. Newly described surgical approaches to the skull base have made possible greater surgical ablation of the skull base region, resulting in large defects and thus heightening the need for reconstructing these regions. Prevention of cerebrospinal fluid leaks is the most important aspect of reconstruction and is achieved most readily when possible by dural patch grafts of fascia lata, coverage of the dura with soft tissue, and preservation of the soft tissue utilizing skin or split thickness skin grafts. Soft tissue may be in the form of free fascia lata grafts, pedicled galeal flaps, or local or regional skin flaps. Defects of the skull base larger than a few square centimeters are best reconstructed with local or regional skin flaps or musculocutaneous flaps. These flaps lend sufficient structural support so that bone support is not usually required. Subsequent cranioplasty, when necessary, can provide protection to those regions of the brain that are more susceptible to blunt trauma.

Cranial Fossa, Posterior↗