Small skull base meningiomas. Surgical management.
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Adult↗
Biomedical subjects
O al-Mefty
Publications and source records attributed to O al-Mefty.
Dislocation of the pituitary gland by sphenocavernous meningiomas.
BACKGROUND: Dislocation of the pituitary gland from the sella turcia by tumor has only very rarely been described. To date, only two cases have appeared in the neurosurgical literature. METHODS: After intraoperative identification of pituitary dislocation in five patients with cavernous sinus meningiomas, a review of our most recent 20 patients with cavernous sinus meningiomas was performed. A subgroup of sphenocavernous meningiomas was identified, as were the associations between pituitary dislocation and the patient's endocrinologic status. RESULTS: Of 20 consecutive patients with cavernous sinus meningiomas, seven tumors could be subclassified as sphenocavernous meningiomas due to the significant amount of tumor extension into the sphenoid sinus. At the time of surgery, dislocation of the pituitary gland from the sella into the suprasellar cistern was observed in five of seven of these patients. Four of the five patients with pituitary dislocation had evidence of hypopituitarism, whereas there was no evidence of this condition in the two patients with sphenocavernous meningiomas without pituitary dislocation. CONCLUSIONS: Pituitary dislocation in these patients is likely due to the physical dislocation of the pituitary gland from the sella, through an incompetent diaphragma sella, and by the tumorous extension in the sphenoid sinus. The extension of a cavernous sinus meningioma into the sphenoid sinus, and specifically the sella turcica, may be via the intercavernous venous sinuses. The lack of endocrinologic improvement suggests that the hypopituitarism noted in these patients is likely due to disturbance of the pituitary microcirculation with subsequent pituitary ischemia. The possibility of pituitary dislocation in patients with sphenocavernous meningiomas, especially those with panhypopituitarism, should be considered and searched for at the time of surgery.
Adult↗
Skull base chordomas: a management challenge.
Because of their critical location, invasive nature, and aggressive recurrence, skull base chordomas are challenging and, at times, frustrating tumors to treat. Both radical surgical removal and high-dose radiation therapy, particularly proton beam therapy, reportedly are effective in tumor control and improve survival rates. The authors posit that these tumors are best treated with radical surgery and proton-photon beam therapy. During the last 5 years, they treated 25 patients (15 females and 10 males) who harbored pathologically diagnosed skull base chordomas. The mean age of the patients was 38.4 years (range 8-61 years). Previous surgery or radiation therapy was performed at other institutions in seven and two patients, respectively. The authors performed 33 surgical procedures on 23 patients. Radical removal (defined as absence of residual tumor on operative inspection and postoperative imaging) was achieved in 10 patients; subtotal resection (defined as resection of > 90% of the tumor) was achieved in 11 patients; and partial resection (defined as resection of < 90% of the tumor) was achieved in two patients. Radical surgical removal included not only the excision of soft-tumor tissue, but also extensive drilling of the adjacent bone. Adjuvant therapy consisted of postoperative combined proton-photon beam therapy (given to 17 patients and planned for one patient) and conventional radiation therapy (two patients); three patients received no adjunct therapy. To date, four patients have died. One patient who had undergone previous surgery and sacrifice of the internal carotid artery died postoperatively from a massive stroke; one patient died from adenocarcinoma of the pancreas without evidence of recurrence; and two patients died at 25 and 39 months of recurrent tumor. Permanent neurological complications included third cranial nerve palsy (one patient) and hemianopsia (one patient); radiation necrosis occurred in three patients. Of the 21 patients followed for more than 3 months after surgery, 16 have had no evidence of recurrence and five (including the two mortalities noted above) have had recurrent tumors (four diagnosed clinically and one radiologically). The mean disease-free interval was 14.4 months. A longer follow-up period will, hopefully, support the early indication that radical surgical removal and postoperative proton-photon beam therapy is an efficacious treatment. The use of skull base approaches based on the tumor classification introduced in this paper is associated with low mortality and morbidity rates.
Adolescent↗
The suboccipital cavernous sinus.
The authors studied the microsurgical anatomy of the suboccipital region, concentrating on the third segment (V3) of the vertebral artery (VA), which extends from the transverse foramen of the axis to the dural penetration of the VA, paying particular attention to its loops, branches, supporting fibrous rings, adjacent nerves, and surrounding venous structures. Ten cadaver heads (20 sides) were fixed in formalin, their blood vessels were perfused with colored silicone rubber, and they were dissected under magnification. The authors subdivided the V3 into two parts, the horizontal (V3h) and the vertical (V3v), and studied the anatomical structures topographically, from the superficial to the deep tissues. In two additional specimens, serial histological sections were acquired through the V3 and its encircling elements to elucidate their cross-sectional anatomy. Measurements of surgically and clinically important features were obtained with the aid of an operating microscope. This study reveals an astonishing anatomical resemblance between the suboccipital complex and the cavernous sinus, as follows: venous cushioning; anatomical properties of the V3 and those of the petrous-cavernous internal carotid artery (ICA), namely their loops, branches, supporting fibrous rings, and periarterial autonomic neural plexus; adjacent nerves; and skull base locations. Likewise, a review of the literature showed a related embryological development and functional and pathological features, as well as similar transitional patterns in the arterial walls of the V3 and the petrous-cavernous ICA. Hence, due to its similarity to the cavernous sinus, this suboccipital complex is here named the "suboccipital cavernous sinus." Its role in physiological and pathological conditions as they pertain to various clinical and surgical implications is also discussed.
Arteries↗
The transcondylar approach to extradural nonneoplastic lesions of the craniovertebral junction.
Ventral extradural lesions at the craniovertebral junction are commonly exposed through the transoral or transmaxillary approach. The disadvantages of these approaches include: 1) difficulty in reaching laterally located lesions; 2) ineligibility of patients with an intradental distance of less than 25 mm or severe macroglossia; 3) the need for a separate procedure for stabilization and fusion; and 4) the risk of infection from transgressing a contaminated field. In this report, the authors describe the use of the transcondylar approach to extradural nonneoplastic lesions of the anterior craniovertebral junction for decompression and stabilization. Advantages of this approach include: 1) a short distance to the lesion; 2) a wide surgical envelope; 3) direct visualization of the dural sac, eliminating manipulation of the brainstem or upper spinal cord; 4) easy identification and control of the ipsilateral vertebral artery; 5) direct visualization and preservation of the lower cranial nerves; and 6) a sterile field. In addition, occipitocervical fusion and instrumentation can be performed during the same procedure. The transcondylar approach, based on anatomical studies in cadavers, was used to treat eight patients with ventral nonneoplastic lesions at the craniocervical junction. The technique and results are described.
Adolescent↗
Significance of proliferating cell nuclear antigen in predicting recurrence of intracranial meningioma.
It is well known that the histological appearance of meningiomas often fails to predict accurately the clinical behavior of the tumor. Therefore, attention has turned from tumor histology to tumor biology. Proliferating cell nuclear antigen (PCNA), a cell cycle-regulated protein, has been recently characterized as the cofactor of DNA polymerase-delta, an enzyme required for DNA replication. The rate of synthesis of PCNA directly correlates with the proliferative state of cells. Immunohistochemical labeling of this antigen is now possible with monoclonal antibodies that allow for its demonstration in routinely fixed, paraffin-embedded specimens. In this study, the PCNA labeling index (LI) was determined for 83 meningiomas, including tumors with both benign and malignant clinical courses and with benign, atypical, and malignant histologies, apparent after total or subtotal resections. No statistical difference was found between the LI on recurrence and that found at initial presentation. In addition, stepwise multivariate regression analysis failed to identify any combination of factors (age, gender, race, age of specimen, tumor histology, Simpson grade of resection) that contributes to the predictive strength of the PCNA LI for tumor recurrence. However, for LIs less than 2%, only one of 26 gross totally resected tumors recurred (mean follow up 53 months); for LIs more than 7%, five of 13 gross totally resected tumors recurred (mean follow up 55 months). The difference in recurrence rates between gross totally resected meningiomas with PCNA LIs less than 2% and those with PCNA LIs more than 7% achieved statistical significance with a Fisher's exact probability equaling 0.011. The authors conclude that quantitative PCNA labeling of meningiomas is a promising technique that can provide meaningful prognostic information.
Adult↗
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↗
Diaphragma sellae meningiomas.
Despite their unique clinical, radiological, and surgical considerations, diaphragma sellae meningiomas remain largely undistinguished from tuberculum sellae meningiomas. On the basis of our experience with 12 patients with diaphragma sellae meningiomas and our review of the literature, we classify these tumors into three groups: Type A, originating from the upper leaf of the diaphragma sellae anterior to the pituitary stalk; Type B, originating from the upper leaf of the diaphragma sellae posterior to the pituitary stalk; and Type C, originating from the inferior leaf of the diaphragma sellae. Each type has specific clinical symptoms. Type A mainly presents with unilateral visual disturbances and visual field defects resembling those of tuberculum sellae meningiomas, although preoperative diabetes insipidus occurred in patients with large tumors. Type B causes fewer visual disturbances, but memory disturbance and hypopituitarism occur. Type C closely resembles nonfunctioning pituitary adenomas; bitemporal hemianopsia and hypopituitarism are common. Multiplanar magnetic resonance images can accurately diagnose the tumor and establish its type. Surgical approaches include the cranio-orbital approach for Types A and B and the transcranial-transsphenoidal approach for Type C. Surgery is more difficult than for tuberculum sellae meningiomas because of the deep location and the difficulty of dissecting Types A and B from the pituitary stalk. Repair of the sphenoid sinus to prevent cerebrospinal fluid leakage is mandatory for Type C tumors.
Adult↗
Experimental chronic compressive cervical myelopathy: effects of decompression.
Twelve dogs developed a delayed onset of neurological abnormalities from chronic cervical cord compression that was characteristic of myelopathy. The animals were divided into two groups and matched according to degree of neurological deficit. Six animals underwent decompression through removal of the anteriorly placed compressive device. Throughout the experiment, serial neurological examinations and somatosensory evoked potential studies were performed on each animal. Spinal cord blood flow measurements were obtained during each surgical procedure and at sacrifice. Magnetic resonance images were obtained after compression and before sacrifice. All animals in the decompressed group showed significant neurological improvement after decompression; no spontaneous improvement in neurological function was seen in the compressed group. On pathological examination, irreversible changes including large motor neuron loss, necrosis, and cavitation were seen in four of the animals in the decompressed group and five in the compressed group. Cervical spondylotic myelopathy in humans is known to respond to decompression; this study provides further evidence that this animal model for chronic compressive cervical myelopathy accurately reflects the disease process seen in humans.
Animals↗
Vascular considerations and complications in cranial base surgery.
The technical evolution of cranial base surgery has resulted in approaches that allow more radical surgical extirpation of complex cranial base lesions. Our service has extensively applied these cranial base approaches for lesions of the cranial base. A subgroup of 100 patients who had cranial base tumors involving potential manipulation or sacrifice of carotid arteries underwent 20-minute balloon test occlusions coordinated with vascular assessments consisting of a combination of the following: 1) four-vessel cerebral angiogram with compression studies; 2) occlusion transcranial Doppler ultrasonography; 3) occlusion single-photon emission computed tomography perfusion studies; and 4) xenon-133 cerebral blood flow studies. Transient neurological deficits associated with balloon test occlusion occurred in 7 of 100 patients (7%). Subsequently, 18 patients underwent permanent carotid occlusion by endovascular detachable balloons. Delayed ischemic complications (> 72 h) occurred in 4 of 18 (22%) patients. Additionally, a number of vascular complications not predicted by the balloon occlusion tests and vascular assessments were experienced. Repeat vascular assessments defined the causes and guided treatment of ischemic patients. Ischemic complications were caused by hemodynamic insufficiency, embolization, vasospasm, radiation vasculopathy, and venous anomaly. Our experience leads us to believe that no vascular assessment exists today that can predict the occurrence of vascular complications accurately. The current enthusiasm for cranial base surgery must be tempered with the sober reality that management of cerebrovascular anatomy and physiology remain significant limitations. Consideration of potential cerebrovascular complications is paramount to successful outcome and implementation of cranial base surgery.
Adult↗
Outcome of aggressive removal of cavernous sinus meningiomas.
Despite recent advances in surgery of the cavernous sinus, meningiomas in that area offer a formidable challenge. The rationale for aggressive surgical removal of cavernous sinus meningiomas is based on the presumption that the extent of removal is inversely related to the rate of recurrence. Over the past 10 years, 41 patients with histologically benign meningiomas involving the cavernous sinus underwent aggressive surgery. Total removal, as confirmed by intraoperative inspection and postoperative radiological studies, was achieved in 31 patients (76%). Twelve patients have been followed for more than 5 years; 10 underwent total tumor removal and only one of these experienced recurrence (5 years after surgery). The other two patients underwent subtotal removal and had symptomatic and radiological evidence of regrowth 3 and 4 years after surgery. Pre-existing cranial nerve deficits improved in only 14% of the patients, remained unchanged in 80%, and worsened permanently in 6%. Seven patients experienced a total of 10 new cranial nerve deficits, four of which involved the nerves subserving ocular motor function. Extraocular muscle function did not worsen in the 25 patients with a seeing eye ipsilateral to the tumor, and no instance of visual worsening occurred. Two patients died 4 months after surgery, one from severe delayed vasospasm and hypothalamic infarction and the other because of a myocardial infarction. Another patient died from a pulmonary embolus on the 9th postoperative day. There were three instances of cerebral ischemia; one was transient, lasting less than 24 hours, while two were related to injury of the middle cerebral artery and resulted in residual hemiplegia. Other complications included three cases of nonfatal pulmonary emboli, two cerebrospinal fluid leaks, and one instance each of exposure keratitis, acute hypothyroidism, and cerebral edema.
Adult↗
The road less traveled: transtemporal access to the CPA.
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Cerebellar Neoplasms↗
Skull base approaches to complex cerebral aneurysms.
The authors used skull base approaches to improve the surgical treatment of cerebral aneurysms. These approaches facilitate aneurysm surgery by allowing early proximal and distal vascular control, shortening and widening of the operative field, increasing the range of the surgeon's operative view and motion, and alleviating brain retraction. Twenty-two patients with ruptured giant or complex aneurysms were operated upon acutely using skull base approaches appropriate for their location: (1) the orbitocranial approach for anterior circulation, ophthalmic artery, and intracavernous lesions (n = 10); (2) the orbitozygomatic approach for aneurysms of the upper third of the basilar artery (n = 6); (3) the petrosal approach for aneurysms of the middle third of the basilar artery (n = 2); and (4) the far lateral-transcondylar approach for vertebrobasilar aneurysms (n = 4). Clipping and dissection of the aneurysms was facilitated by the skull base approaches. No surgical mortality occurred in this series of patients; transient cranial nerve paresis was the only morbidity related to the approaches. We compare the three-dimensional spatial geometry of skull base and conventional approaches, and discuss the advantages and nuances of skull base approaches.
Adult↗
Significance of MRI changes after surgery of the skull base.
Magnetic resonance (MR) imaging is commonly used in the followup of patients who have undergone surgical removal of tumors from the cranial base to assess the possibility of tumor recurrence, persistence, or surgical complications. Interpretations of this study must be cautious because postoperative enhanced signals are encountered frequently. Although technological improvements continue to enhance the usefulness of MR images for followup, problems remain in differentiating between fibrotic, reconstructive changes, and tumor recurrence. In this study, the hospital records and MR findings of 215 patients who had undergone skull base surgery were reviewed. The study was prompted by negative operative exploration in three patients in whom postoperative MR images strongly suggested tumor recurrence. One-year follow-up images were available in 174 patients. Of these, 94% showed signal enhancement on the 1-year follow-up study. Progressive changes were observed in 14% of patients. The correlation of preoperative MR findings and surgery, with regard to dural involvement, vascular involvement, cranial nerve infiltration, and extent of intracranial infiltration, was analyzed in 28 patients. Methods to facilitate the detection of tumor recurrence using MR images are reviewed.
Adult↗
Orbitocranial exposure in the management of infratemporal fossa tumors.
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Adenocarcinoma↗
The "subdural" space: a new look at an outdated concept.
This review considers the structure of the meninges, as seen at the electron microscopic level, with particular emphasis on the dura-arachnoid junction and whether a naturally occurring space is found at this interface. The classic view has been that a so-called subdural space is located between the arachnoid and dura and that subdural hematomas or hygromas are the result of blood or cerebrospinal fluid accumulating in this (preexisting) space. The dura is composed of elongated, flattened fibroblasts and copious amounts of extracellular collagen. A specialized layer of fibroblasts, the dural border cell layer, is found at the dura-arachnoid junction and is characterized by flattened fibroblasts, no extracellular collagen, extracellular spaces, and few cell junctions. These features combine to create a layer of the inner dura that is structurally weak when compared with external portions of the dura and the internally located arachnoid. The arachnoid layer is composed of larger cells with numerous cell junctions, no extracellular space, and no extracellular collagen. The occurrence of many tight junctions in this layer also serves as a barrier to the movement of fluids and ions. Fibroblasts specialized to form the arachnoid trabeculae attach to the inner surface of the arachnoid layer, bridge the subarachnoid space, and surround vessels in the subarachnoid space as well as attach to pia on the surface of the brain. Under normal conditions, there is no evidence of a naturally occurring space being extant at the dura-arachnoid junction. A space may appear at this point subsequent to pathological/traumatic processes that result in tissue damage with a cleaving opening of the structurally weakest plane in the meninges--through the dural border cell layer. Furthermore, when a space does appear, it is not "subdural" in location but rather within a morphologically distinct cell layer.
Animals↗
Use of vascularized fat from the rectus abdominis myocutaneous free flap territory to seal the dura of basicranial tumor resections.
Resection of large skull base tumors may sometimes result in extirpation defects that are not amenable to local tissue closure. Patients with these tumors require free tissue transfer for closure of the intracranial space after basicranial tumor extirpation. The deep inferior epigastric artery supplies the rectus abdominis muscle and the skin and subcutaneous tissue of the lower abdomen. The closure of massive, central defects can be performed with a free flap designed from the ample rectus abdominis vascular territory. This free tissue donor site has abundant and reliable well-vascularized skin and subcutaneous tissue that can be customized to seal these tenuous areas and provide three-dimensional reconstruction. We have modified the rectus abdominis myocutaneous free flap in seven patients for reconstruction of the skull base. The subcutaneous fat was sculptured to form a soft, vascularized "cork" and was used for obliteration of the irregular deep portions of defects at the midcranial base against the repaired or unrepaired dura. All patients who had the vascularized fat used to obliterate the deep space had successful closure of the defect without cerebral spinal fluid leak. There were two wound infections and one donor-site hernia in this group. The judicious use of the vascular territory of the deep inferior epigastric vessels can accomplish secure three-dimensional reconstruction of the skull base. The flap can be reliably transferred, and the vascularized subcutaneous fat can be used to sequester and seal the dura repair.(ABSTRACT TRUNCATED AT 250 WORDS)
Adenocarcinoma↗