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Biomedical subjects

J M Tew

Publications and source records attributed to J M Tew.

At least 37 records · Page 2Linked to original sources
PubMed1998

Combined interventional and surgical treatment of arteriovenous malformations.

This article describes the combined interventional and surgical treatment of arteriovenous malformations. The development of embolization as an adjunct to microsurgical resection of arteriovenous malformations has expanded the therapeutic armamentarium in the treatment of these lesions. Patient selection, indications, technical aspects as well as avoidance and treatment of complications with regard to endovascular embolization are discussed. Four individual cases are presented to show how embolization can be combined with microsurgery to achieve optimal treatment results.

Adult↗
PubMed1997

Anterior petrosectomy approach to infraclinoidal basilar artery aneurysms: the emerging role of the neuro-otologist in multidisciplinary management of basilar artery aneurysms.

Aneurysms of the basilar artery are uncommon. Historically, because of the central location of these basilar lesions, surgical access has been difficult. Moreover, while this disease and its surgical management inherently carry a high risk of patient morbidity, the presence of neighboring vital neural and vascular structures introduces additional intraoperative challenges. Since 1986 we have employed a transpetrous approach for access to selective aneurysms involving the basilar artery. Removal of the petrous apex has provided an expanded deep window through which infraclinoidal basilar artery aneurysms can be controlled. Reported herein are our results utilizing an anterior petrosectomy approach to the management of infraclinoidal artery aneurysms.

Adult↗
PubMed1997

Surgical management of deep-seated dural arteriovenous malformations.

The best treatment for deep-seated dural arteriovenous malformations (AVMs) remains controversial. Therapeutic options include transarterial and transvenous embolization, surgical excision of the dural nidus, ligation of draining veins, and stereotactically guided radiation treatment. The authors report on their experience with the application and technique of skull base surgical approaches for deep-seated dural AVMs. Their series includes six patients who were surgically treated for five tentorial dural AVMs and one inferior petrosal sinus dural AVM between 1991 and 1995. Three patients presented with progressive brainstem dysfunction, one had progressive myelopathy, and two suffered subarachnoid hemorrhage. Venous hypertension caused progressive neurological deterioration in four patients and ruptured venous aneurysms caused hemorrhage in two patients. Four of the five tentorial dural AVMs received bilateral arterial supply from the internal carotid arteries and external carotid arteries (ECAs). The dural AVM of the inferior petrosal sinus was fed from both vertebral arteries and ECAs. In this series, all dural AVMs drained into deep cerebral veins. Intra- and postoperative angiographic studies were used to document complete obliteration in each case. After surgery, three patients developed transient, delayed (24-72 hours) neurological worsening. One month postsurgery, all six patients showed improvement from their preoperative neurological function. Surgical resection of these deep-seated dural AVMs was accomplished by eliminating the arterial supply rather than ligating the draining veins to avoid aggravating the underlying venous hypertension. This study demonstrates an important role for skull base surgical approaches in the management of patients with deep-seated dural AVMs that have hemorrhaged, are not obliterated by embolization, and for which stereotactically guided radiation therapy is an unsuitable option.

Aged↗
PubMed1997

The surgical resectability of meningiomas of the cavernous sinus.

OBJECTIVE: The optimal management for patients with cavernous sinus meningiomas remains controversial. We attempt to contribute to the ongoing debate of appropriate surgical indications. METHODS: In this retrospective review, 39 patients, including 27 women and 12 men ranging in age from 24 to 73 years (median, 48 yr), underwent surgical treatment for this condition. Completeness of tumor resection, cranial nerve morbidity, general morbidity, and long-term outcome were studied. The cavernous internal carotid artery was partially encased in 15 patients, totally encased in 11 patients, and narrowed by tumor in 13 patients. RESULTS: Of eight patients who underwent complete tumor resection, seven had partial encasement of the internal carotid artery. Of 31 patients who underwent subtotal resection, 11 underwent postoperative radiotherapy. There were no deaths in the series. Morbidity was 17.9% for cranial nerves controlling extraocular motor function. Trigeminal nerve function did not improve after surgical treatment. The median follow-up period was 2 years (range, 6 mo-5.3 yr). Symptomatic and radiographic recurrence occurred in two patients who underwent complete tumor resection and in two patients who underwent subtotal resection. CONCLUSION: Based on our findings and a review of the literature, we conclude the following: 1) the resectability of meningiomas of the cavernous sinus depends on the degree of internal carotid artery involvement; 2) total excision of cavernous sinus meningiomas is possible but rarely achieved in holocavernous meningiomas; 3) cranial nerve morbidity is significant; and 4) subtotal excision with or without postoperative radiotherapy is an effective short-term oncological strategy.

Adult↗
PubMed1997

Cervical myelopathy associated with intracranial dural arteriovenous fistula: MR findings before and after treatment.

The MR findings in three patients with intracranial dural arteriovenous fistula associated with cervical myelopathy are described. The MR appearance of an enlarged cord with associated abnormal signal and enhancement is nonspecific and can simulate tumor, demyelination, and inflammation. Enlarged perimedullary vessels may not always be identifiable, but if present, should suggest the presence of an arteriovenous fistula.

Aged↗
PubMed1996

Role of genomic instability in meningioma progression.

Microsatellite length instability, probably resulting from defective DNA mismatch repair mechanisms, has been described in a variety of cancers. Such genetic instability may play a significant role in tumor formation and progression. To investigate the role of microsatellite alterations in meningioma tumorigenesis and progression, we examined 33 microsatellite markers on nine chromosomes for abnormalities in 18 benign, 15 atypical, and 11 malignant meningiomas. In each tumor, at least 15 markers were investigated. Microsatellite instability was not detected in any of the cases examined. However, loss of heterozygosity for markers from various chromosomes was seen frequently among atypical and malignant meningiomas. Although some of these chromosomal losses might represent random events, our data also indicate a role for specific loci on chromosome arms 14q, 1p, 10q, and possibly 9p in the development of malignancy in meningiomas. Our results argue against a significant role for a generalized microsatellite instability phenotype in meningiomas, but they suggest that genomic instability resulting in frequent allelic deletions may contribute to meningioma progression.

Alleles↗
PubMed1996

Comparison of surgical treatments for trigeminal neuralgia: reevaluation of radiofrequency rhizotomy.

In this study, we reevaluate the results of radiofrequency rhizotomy and review the effectiveness of other surgical procedures for the treatment of trigeminal neuralgia. Five hundred patients with trigeminal neuralgia underwent radiofrequency rhizotomy at the University of Cincinnati Medical Center, Cincinnati, OH, between 1981 and 1986. Their results are compared with those of patients reported in the literature who underwent radiofrequency rhizotomy (6205 patients), glycerol rhizotomy (1217 patients), balloon compression (759 patients), microvascular decompression (MVD) (1417 patients), and partial trigeminal rhizotomy (250 patients). Comparisons were based on the following outcome parameters: technical success, pain relief and recurrence, facial numbness, dysesthesia, corneal anesthesia, keratitis, trigeminal motor dysfunction, permanent cranial nerve deficit, intracranial hemorrhage or infarction, perioperative morbidity, and perioperative mortality. We found that MVD had the lowest rate of technical success. Radiofrequency rhizotomy and MVD had the highest rates of initial pain relief and the lowest rates of pain recurrence. Glycerol rhizotomy had the highest rate of pain recurrence. Balloon compression had the highest rate of trigeminal motor dysfunction. Balloon compression and MVD had the lowest rates of corneal anesthesia or keratitis. MVD had the lowest rates of facial numbness and dysesthesia. All percutaneous procedures had similar rates of dysesthesia. Posterior fossa exploration had the highest rates of permanent cranial nerve deficit, intracranial hemorrhage or infarction, and perioperative morbidity and mortality. On the basis of our experience and a review of the literature, we conclude the following: 1) percutaneous techniques and posterior fossa exploration offer advantages and disadvantages, 2) radiofrequency rhizotomy is the procedure of choice for most patients undergoing first surgical treatments, and 3) MVD is recommended for healthy patients who have isolated pain in the first ophthalmic trigeminal division or in all three trigeminal divisions and patients who desire no sensory deficit.

Adult↗
PubMed1996

Meningeal architecture of the cavernous sinus: clinical and surgical implications.

OBJECTIVE: The meningeal structure of the cavernous sinus (lateral sellar compartment) was anatomically and histologically studied. We discuss the clinical and surgical significance and present clinical examples of cranial base tumors. METHODS: Ten adult cadaveric heads were used for microsurgical dissection or histological studies. Specimens of the cavernous sinus were continuously sectioned in three dimensions and stained by Masson's trichrome method. The findings are anatomically discussed as they pertain to presented clinical cases. RESULTS: The cavernous sinus, located in an interdural space between periosteal and meningeal dura, is properly accessed by detachment of the periosteal bridge between the superior orbital fissure and the middle fossa. The lateral meningeal dura is dissected under minimal hemorrhage from the sinus, with a surgically important cleaving plane between the "deep layer," a semitransparent meningeal sheath with which the cranial nerves are covered and protected. It has various degrees of meningeal pockets, of which Meckel's cave is the largest example. Adventitia of the carotid artery in the sinus, uncovered with protective meninges, is considered to contact directly with tumors of the sinus origin. The meningeal wall of the cavernous sinus anatomically has three weak points as far as tumor invasion and extension are concerned: the venous plexus around the superior orbital fissure, the loose texture of the medial wall around the pituitary body, and dural pockets of the IIIrd and Vth cranial nerves. The dural wall is extremely thin or missing at those points. CONCLUSION: A surgical technique based on the meningeal anatomy is important for cavernous sinus surgery. The cavernous apex and Meckel's cave, which are spaces of convergence of cranial nerves, however, are weak points for surgical dissection. The presence or absence of tumor invasion into those areas may influence the microsurgical results.

Adult↗
PubMed1996

Long-term results in direct carotid-cavernous fistulas after treatment with detachable balloons.

Transarterial embolization of direct carotid-cavernous fistulas (CCFs) using detachable balloons is the best initial option for occlusion of the fistula and preservation of the internal carotid artery. However, the long-term safety and efficacy of this treatment is unknown. The authors reviewed the long-term outcome of 87 patients with 88 direct CCFs occluded by detachable balloons. Clinical follow up was obtained in 48 (83%) of 58 patients treated with latex balloons (mean follow-up period 10 years, range 5.9-15.5 years) and 28 (97%) of 29 patients treated with silicone balloons (mean follow-up period 4 years, range 1-6.6 years). Two patients were treated with both balloon types. There were no late recurrent symptoms of cranial bruit, proptosis, chemosis, or arterialized conjunctiva in patients treated with either latex or silicone balloons. Diplopia improved in all patients; however, five patients required shortening of the lateral rectus muscle. Delayed ischemia occurred in three patients: one patient had a transient ischemic episode 5 years after treatment with latex balloons and two patients (85 and 90 years old) who had ruptured spontaneous intracavernous aneurysms suffered cerebral infarctions 6 weeks and 4 months, respectively, after treatment with silicone balloons. There were five deaths in the series unrelated to balloon treatment. These results show that after transarterial embolization of direct CCFs using either silicone or latex detachable balloons, the long-term risks are low for fistula recurrence, symptomatic foreign body reaction, symptomatic pseudoaneurysm formation, and cerebral ischemia.

Adolescent↗
PubMed1996

Recurrence of hemifacial spasm after microvascular decompression.

The success of medical and surgical treatment for hemifacial spasm, and involuntary paroxysmal unilateral contraction of the facial muscles, has been mixed. Although microvascular decompression has the greatest reported success, symptom recurrence affects many patients in whom treatment was initially successful. In this study, we report the results of 34 patients who underwent microvascular decompression of the facial nerve from 1976 to 1989 as well as review the literature concerning the incidence and timing of recurrence in more than 600 patients who underwent microvascular decompression. In this series, 94% of 34 patients had continuous relief of spasm after surgical treatment (mean duration, > 6 yr). Of those patients whose spasms were completely initially relieved, 10.3% developed some degree of recurrent spasm; however, no patient developed a recurrence after 24 months without spasm. Our review of the literature discloses that 86% of all recurrences occurred within 2 years of surgery. Patients who have no recurrence of symptoms 2 years after surgical treatment have only a 1% chance of developing recurrent hemifacial spasm. We also comment on possible causes of treatment failure and recurrence of hemifacial spasm after surgical treatment.

Adult↗
PubMed1995

Allelic losses on chromosomes 14, 10, and 1 in atypical and malignant meningiomas: a genetic model of meningioma progression.

To investigate chromosomal events that underlie formation and progression of meningiomas, we have examined a set of 18 benign (WHO grade I), 15 atypical (grade II), and 13 anaplastic/malignant (grade III) meningiomas for loss of heterozygosity (LOH) on chromosomes 1p, 6p, 9q, 10q, and 14q. Frequent loss of loci on these chromosomes was seen in grade II and grade III tumors, specifically, 14q (II and III, 47 and 55%), 1p (40 and 70%), and 10q (27 and 40%). In contrast, LOH for these loci was infrequent in benign meningiomas, specifically, 14q (0%), 1p (11%), and 10q (12%). The smallest common regions of deletion that could be defined were 14q24-q32, 1p32-pter, and 10q24-qter. These observations indicate the likely presence of tumor suppressor genes in these regions that are involved in the development of WHO grade II and grade III meningiomas. Because LOH for loci on chromosomes 1p and 10q was found in tumors of all grades and because the frequency of LOH in all three regions increased with tumor grade, these results would support a model for the formation of aggressive meningiomas through tumor progression.

Adult↗
PubMed1995

Long-term results of radiofrequency rhizotomy in the treatment of cluster headache.

Although the primary treatment of chronic cluster headache is medical, surgical treatment is sometimes used. The authors reviewed the charts of seven patients (ages 36 to 68 years) with chronic cluster headache to identify who responded best to percutaneous stereotactic radiofrequency rhizotomy after medical treatment failed. All patients had immediate pain relief after surgery. At follow-up (median 5 years, range 2 to 20 years), two patients remained pain-free 7 and 20 years later (excellent results); three patients had mild pain recurrence that was well controlled on medications (good results) 6 to 12 months after surgery; and two patients had major pain recurrence 4 days and 2 months after surgery (poor results). Six patients had relief of vasomotor symptoms. One patient had transient diplopia and keratitis without permanent sequelae. Both patients with excellent results had preoperative major pain around the eye; both patients with poor results had major pain around the temple, ear, and cheek; and the three patients with good results had pain equally severe in the eye, temple, and cheek. There was no association between patient age or sex, pain duration, preoperative response to lidocaine blockade, or previous surgery with pain relief. No differences occurred in pain relief between patients with dense hypalgesia and patients with analgesia. The authors conclude that (1) some patients with chronic cluster headache treated by percutaneous stereotactic radiofrequency rhizotomy achieve long-term pain relief, and (2) surgery on the trigeminovascular system alone may not cure the condition in patients with major pain around the temple, ear, and cheek.

Adult↗
PubMed1995

Management of 100 consecutive direct carotid-cavernous fistulas: results of treatment with detachable balloons.

Direct carotid-cavernous fistulas are high-flow shunts with a direct connection between the internal carotid artery and the cavernous sinus. The goals of treatment are to eliminate the fistula and preserve carotid artery patency. The authors reviewed the outcome of 98 patients with 100 consecutive direct carotid-cavernous fistulas initially treated by transarterial embolization with detachable balloons (1979-1992) at the University of Cincinnati Medical Center to evaluate the merits of this technique and to provide a standard for comparison with future treatment alternatives. Among 100 fistulas, 76 were traumatic in origin, 22 resulted from a ruptured aneurysm, and 2 were iatrogenic. The most common presentations were orbital bruit (80%), proptosis (72%), chemosis (55%), abducens palsy (49%), and conjunctival injection (44%). Eighty-eight fistulas were successfully occluded in 86 patients with detachable balloon(s), and internal carotid blood flow was preserved in 66 patients (75%). Initial attempts at balloon occlusion failed in four patients in whom the fistula eventually closed spontaneously. Five patients required direct surgery to occlude the fistula, and two were treated with nondetachable balloons; one patient died from injuries sustained from trauma. The permanent neurological complication rate was 4%, including cerebral infarction in one patient, frontal intracerebral hemorrhage in one patient, and vision loss in another patient. One death occurred related to cerebral infarction from a balloon that shifted. Transient ischemia occurred in three patients. On the basis of these results, we conclude that transarterial embolization with detachable balloons provides a high rate of fistula obliteration with low morbidity and is the best initial procedure to treat direct carotid-cavernous fistulas.

Adolescent↗
PubMed1995

Long-term results of surgical treatment of idiopathic neuralgias of the glossopharyngeal and vagal nerves.

Physicians disagree about the best surgical treatment for patients with idiopathic neuralgias of the glossopharyngeal and vagal nerves after medical treatment has failed. Some favor percutaneous thermal rhizotomy, and other prefer extracranial section of the glossopharyngeal or branches of the vagal nerve, intracranial section of the glossopharyngeal and upper vagal rootlets, or microvascular decompression. However, the results of these procedures are limited to series with follow-up periods of less than 5 years or to series with longer follow-ups that were performed before the microneurosurgical era. We reviewed the long-term results of 14 patients with vagoglossopharyngeal neuralgia treated surgically at our center between 1976 and 1987 to determine the best treatment. Sixteen procedures were performed: 2 percutaneous thermal rhizotomies; 2 extracranial sections of the superior laryngeal nerve; and 12 intracranial glossopharyngeal and upper vagal rhizotomies, 4 with and 8 without microvascular decompression. The follow-ups ranged from 4 to 17 years (mean, 10 yr). All 14 patients who underwent percutaneous or intracranial rhizotomies were pain free. Two patients who underwent percutaneous rhizotomies developed persistent dysphagia and hoarseness. Both patients who underwent extracranial nerve section experienced pain recurrence 2 and 4 years later. Of 12 patients who underwent intracranial section of the glossopharyngeal and upper vagal rootlets, 2 developed dysphagia, which resolved completely in 1 patient and persisted mildly in the other; 1 had transient hoarseness; and 2 developed frequent coughing episodes, which persisted in 1 patient and resolved completely in the other. Side effects due to motor vagal deficits may be eliminated by intraoperative monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Management strategies and surgical techniques for deep-seated supratentorial arteriovenous malformations.

The therapeutic options for arteriovenous malformations (AVMs) of the thalamus and the basal ganglia have expanded to include preoperative embolization, stereotactic radiation, and microsurgery. Adjuncts to surgery such as stereotactic guidance, electrophysiological monitoring, intraoperative ultrasound, intraoperative angiography, and induced hypotension have significantly reduced postoperative morbidity. We review the management and outcome of 65 consecutive patients who were treated for deep-seated supratentorial vascular malformations; 45 patients (69%) were treated surgically, 10 patients (15%) were treated conservatively, and 10 patients (15%) underwent radiosurgery. This retrospective study (1976-1993) includes 51 AVMs (78%), 14 cavernous angiomas (22%), and 10 associated vascular anomalies (15%). Initially, 59 (91%) of 65 patients presented with hemorrhage; 23 patients (39%) suffered recurrent hemorrhages. Malformations ranged in size from 1 to 7.5 cm (mean, 2.8 cm). AVMs were fed principally by the anterior and posterior choroidal, thalamoperforate, and lenticulostriate arteries. Venous drainage was uniform via the deep venous system. Among 39 patients who underwent surgery for AVMs, 26 (67%) improved, 7 (18%) remained unchanged, 5 (13%) worsened, and 1 (3%) died. Among six patients who underwent surgery for cavernous angiomas, four (66%) improved, one (17%) remained unchanged, and one (17%) worsened. Operative complications included transient neurological deficits in seven patients (16%), permanent neurological deficits in six patients (13%), and new bleeding from residual AVMs in four patients (9%). Among 10 patients treated conservatively, 3 (30%) had repeat hemorrhages, 2 (20%) had progressive neurological deficits, and 1 (10%) died.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗