Biomedical subjects

W Pellet

Publications and source records attributed to W Pellet.

At least 37 records · Page 2Linked to original sources

PubMed2001

Long-term outcome after gamma knife surgery for secondary trigeminal neuralgia.

OBJECT: This study was directed to evaluate the potential role of gamma knife surgery (GKS) in the treatment of secondary trigeminal neuralgia (TN). The authors have identified three anatomicoclinical types of secondary TN requiring different radiosurgical approaches. METHODS: Pain control was retrospectively analyzed in a population of patients harboring tumors of the middle or posterior fossa that involved the trigeminal nerve pathway. This series included 53 patients (39 women and 14 men) treated using GKS between July 1992 and June 1997. The median follow-up period was 55 months. Treatment strategies differed according to lesion type, topography, and size, as well as visibility of the fifth cranial nerve in the prepontine cistern. Three different treatment groups were established. When the primary goal was treatment of the lesion (Group IV, 46 patients) we obtained pain cessation in 79.5% of cases. In some patients in whom GKS was not indicated for treatment of the lesion, TN was treated by targeting the fifth nerve directly in the prepontine cistern if visible (Group II, three patients) or in the part of the lesion including this nerve if the nerve root could not be identified (Group III, four patients). No deaths and no radiosurgically induced adverse effects were observed, but in two cases there was slight hypesthesia (Group IV). The neuropathic component of the facial pain appeared to be poorly sensitive to radiosurgery. At the last follow-up examination, six patients (13.3%) exhibited recurrent pain, which was complete in four cases (8.8%) and partial in two (4.4%). CONCLUSIONS: The results of GKS regarding facial pain control are very similar to those achieved by microsurgery according to series published in the literature. Nevertheless, the low rate of morbidity and the greater comfort afforded the patient render GKS safer and thus more attractive.

Adolescent↗

PubMed2001

[Recurrent acoustic neurinoma after complete surgical resection].

BACKGROUND: Mortality of acoustic neurinoma surgery is currently very low, well below the figures reported by the first surgeons. Morbidity has also declined with attempts at preserving the facial function and more recently hearing function. Long-term follow-up has demonstrated the well-known risk of recurrence after partial resection, but also evidenced a risk after complete resection. PATIENTS AND METHODS: We reviewed two series of patients, the first including 40 patients treated and followed at the Timone Hospital since 1975 and the second including 97 operated patients who were followed by the ENT Federation over 8 to 16 years. We studied recurrence after partial and complete resection. RESULTS: Recurrence rate was 20% after partial resection and 9.2% after complete resection. DISCUSSION: The 20% recurrence rate after partial resection was similar to that reported in the literature. After total extirpation, our 9.2% recurrence rate appears well above the 1% reported by others. Although our series could have a bias due to the large number of patients lost to follow-up, the large population size and the fact that we had a majority of large tumors would suggest that recurrence rate is generally underestimated. An 8 to 10% rate appears to be closer to reality. Most recurrences were late, with a peak around 8 years. We did however observe recurrences as early as 1 year and as late as 20 years. Delay appears to be shorter after partial removal. A wide range of localizations were observed but two areas predominated: the internal auditory canal and the components of the acousticofacial pedicle, and to a lesser degree the brain stem. Most patients were asymptomatic. The principal manifestations were balance disorders or trigeminal nerve lesions, more rarely facial palsy. But these clinical signs came late and generally signaled a bulky tumor measuring more than 3 cm. CONCLUSION: These findings lead us to insist on the need for radiological monitoring of all operated neurinomas irrespective of the initial surgery. MRI appears to be more accurate than computed tomography. Images must be interpreted carefully due to possible postoperative remodeling. For us, these observations point to the need for prolonged follow-up of at least 8 years, longer for young subjects, for all patients undergoing surgical resection of an acoustic neurinoma.

Adolescent↗

PubMed2000

Gamma knife radiosurgery as a primary treatment for prolactinomas.

OBJECT: The purpose of this study was to estimate the efficacy of gamma knife radiosurgery (GKS) in controlling tumor growth and endocrinopathy associated with prolactinomas. METHODS: Between 1993 and 1997, 164 of 469 patients with pituitary adenomas treated by GKS harbored prolactinomas. The dose to the tumor margin ranged from 9 to 35 Gy (mean 31.2 Gy), and the visual pathways were exposed to a dose of less than 10 Gy. The mean tumor diameter was 13.4 mm. The mean follow-up time for 128 cases was 33.2 months (range 6-72 months). Tumor control was observed in all but two patients who underwent surgery 18 and 36 months, respectively, after GKS. Clinical cure was achieved in 67 cases. Clinical improvement was noted with a decrease in the hyperprolactinemia after GKS. Nonetheless, in 31 (29%) of 108 patients who were followed for more than 2 years no improvement in serum prolactin levels was demonstrated, although this could be normalized by bromocriptine administration after treatment. Nine infertile women became pregnant 2 to 13 months after GKS and all gave birth to normal children. There was no visual deterioration related to GKS. Five women experienced premature menopause. In these patients there was subtotal disappearance of the tumor and an empty sella developed. CONCLUSIONS: Gamma knife radiosurgery as a primary treatment for prolactinomas can be safe and effective both for controlling tumor growth and for normalization of prolactin hypersecretion. A higher margin dose (> or = 30 Gy) seemed to be associated with a better clinical outcome. Gamma knife radiosurgery may make prolactinomas more sensitive to the bromocriptine.

Humans↗

PubMed2000

[Neurofibromatosis type 2. Preliminary results of gamma knife radiosurgery of vestibular schwannomas].

BACKGROUND AND PURPOSE: The aim of this study was to assess tolerance and efficacy of gamma knife radiosurgery on vestibular schwannomas for patients affected with neurofibromatosis type 2. METHODS: Between July 1992 and December 1997, a gamma knife procedure was performed on 35 vestibular schwannomas affecting 27 patients (12 females and 15 males, mean age=27 years-old, range: 14-65). Fifteen of the patients were included in the Wishart subtype (severe form) and 12 patients in the Gardner subtype (mild form). This group of 27 patients represented 8,2% of the total group of vestibular schwannomas radiosurgically treated by our team. The mean tumor volume was 4,000 mm(3) (range: 400-14,400 mm(3)) and staging according to Koos classification was 9 stage 2 tumors (extension in the cerebellopontine angle), 19 stage 3 tumors (in contact with the brain stem or cerebellum) and 7 stage 4 tumors (compression of axial structures). The delivered mean marginal dose (50% isodose) was 13 Gy (range: 10-18 Gy). After the treatment, the mean clinical and radiological follow-up was 32 months (range: 6-70). RESULTS: Twenty six (74%) of the treated tumors were controlled by the treatment (15 stabilizations and 11 regressions of the tumor volume) at last follow-up. One microsurgical removal was required in a growing stage 4 tumor and in 2 cases of growing stage 3 tumors. Three post-radiosurgical facial nerve deficits (9%) were observed, 2 of them were transient. According to the Gardner and Robertson classification, classes I (good) and II (serviceable) hearing were preserved at last follow-up in 57% of the patients having the same hearing level prior to the gamma knife. CONCLUSIONS: Our experience confirms that tolerance of gamma knife radiosurgery compares favorably with microsurgery of bilateral vestibular schwannomas. This treatment should be restricted to small and medium growing tumors. Treatment strategy of neurofibromatosis type 2 patients should be planned by multidisciplinary experienced teams disposing of the whole armamentarium. A longer follow-up study is required to confirm the current results regarding the tumor control rate.

Adolescent↗

PubMed2000

[Endolymphatic sac tumors].

Tumors of the endolymphatic sac are rare and can be found in patients with Von Hippel Lindau disease. They most often develop within the intrapetrosal part of the sac but can sometimes be located in the distal part. Their growth is slow and they spread in two directions: laterally toward the external and middle ear and in the direction of the jugular foramen and medially into the ponto-cerebellar angle. The symptoms are usually auditive, with a constant neurosensorial deafness of sudden onset in 50 % of cases and sometimes associated with a tinnitus and dizziness. The varieties with medial extension result in a cerebellopontine angle syndrome. Diagnosis is made by imaging (CT scan and MRI) that reveals a heterogeneous tumor between the lateral sinus and the internal auditory meatus, hypervascularized showing contrast, with cystic zones and associated with bone lysis. Histological examination of a papillary cystadenoma is performed and the differential diagnosis is essentially made with a papillary of the choroïd plexus. They require total surgical excision in order to avoid possible recurrence and can be performed by retrosigmoïd approach, or more ideally, by transpetrosal approach.

Adult↗

PubMed1999

Gamma Knife radiosurgery of the glomus jugulare tumour - early multicentre experience.

Leksell Gamma Knife was used to treat 66 patients with glomus jugulare tumour at 6 European sites between 1992-1998. The age of the patients ranged between 18-80 years (median 54 years). Gamma Knife radiosurgery was a primary treatment in 30 patients (45. 5%). Open surgery preceded radiosurgery in 24 patients (36.4%), embolisation in 14 patients (21.2%) and fractionated radiotherapy in 5 patients (7.6%). The volume of the tumour ranged 0.5-27 cm(3) (median 5,7 cm(3)). The minimal dose to the tumour margin ranged between 10-30 Gy (median 16.5 Gy). After radiosurgery 52 patients were followed, the follow up period was 3-70 months (median 24 months). Neurological deficit improved in 15 patients (29%) and deteriorated in 3 patients (5,8%), one transient and two persistant. Neuroradiological follow up using MRI or CT was performed in 47 patients 4-70 months (median 24 months) after radiosurgery. Tumour size decreased in 19 patients (40%) while in the remaining 28 patients (60%) no change in the tumour volume was observed. None of the tumours increased in volume during the observation period. Control angiography was performed in 6 patients. Pathological vascularisation completely disappeared in one patient, reduced in two and there was no change in the remaining three. Radiosurgery proves to be a safe treatment for glomus jugulare tumour with no mortality and no acute morbidity. Because of its naturally slow growth rate, up to 10 years of follow up will be necessary to establish a cure rate after radiosurgery for these lesions.

Adolescent↗

PubMed1999

[Translabyrinthine approach and venous prolapses (jugular bulb and lateral sinus)].

Temporal bone venous prolapse with or without meningeal prolapse are a frequent problem in middle ear and labyrinth surgery. 178 translabyrinthine approaches with prolapse study are reported in this retrospective study. Superficially, the approach was narrow in 43% of the patients because of a lateral sinus prolapse in 27 cases or a temporal meningeal prolapse in 50 patients. Surgery was technically difficult in 8 patients with lateral sinus prolapse associated with meningeal prolapse. Deep labyrinth structure reaming was difficult in 40% because of an abnormal position of the jugular bulb and/or the superior petrosal sinus. Both superficial and deep approach was narrow in 22% of the cases. 23 lateral sinus prolapses associated with transhigh jugular bulb and 17 lateral sinus prolapses associated with superior petrosal sinus prolapses were noted and reported. Expectation of these anatomical variations, more frequent on the right side, should be established before surgery with imaging studies in order to perform a safe and efficient surgical procedure.

Cranial Sinuses↗

PubMed1999

[Lumbar canal stenosis caused by amyloidosis of the yellow ligament].

Symptomatic lumbar canal stenosis without bony stenosis has previously been described. We describe the pathological modifications of ligamentum flavum among such operated patients. Ten patients were prospectively included in this study. Their mean age was 74, ranges: from 52-90. Clinical manifestation was a radicular claudication (sciatic or crural). Neuroradiology confirmed in all cases the ligamentum flavum thickness as the main cause of the symptomatology. This feature was also confirmed operatively and complete resection of the ligamentum flavum was performed. Resolution of the radicular pain was obtained in all cases at last follow-up. Pathological examination of the ligamentum flavum displayed characteristic features of degenerative modifications and elastic fibers fragmentation caused by numerous amorphous deposits. The deposits were studied using red Congo staining, polarized light and immunostaining methods. Such technique showed evidence of amyloid origin of the deposits. Immunodetection was positive for the P component in the amyloid deposits and for beta-2-microglobulin in one case (chronic renal failure and hemodialysis). The deposits did not express antitransthyretin antibodies. In parallel, control ligamentum flavum were obtained from 10 operated patients affected by bony lumbar stenosis. Moderate degenerative features were observed but small amounts of amyloid deposits were found in only 3 of those cases, without thickening of the ligamentous structure. This study correlates the presence of thickened ligamentum flavum caused by amyloid deposition, with symptomatic non-osseous lumbar canal stenosis. Association with degenerative modifications of the spine in the studied cases is suggestive of a microtraumatic origin.

Aged↗

PubMed1999

[Dural metastases mimicking meningioma. Report of a case].

We report a case of dural metastasis, detailing the neuroradiologic and therapeutic aspects. The clinical presentation was limited to a progressive left hemiparesis. Post-contrast CT scan revealed a heterogeneous high-density mass of the right fronto-parietal convexity. MRI demonstrated dural involvement mimicking meningioma. Chest X-ray showed a right lung opacity, suggesting the diagnosis of dural metastasis. Surgical resection was performed. Histology confirmed the diagnosis of dural metastasis from a poorly differentiated carcinoma. Treatment was completed with radiotherapy and chemotherapy. Dural metastases are rarely reported. A review of the literature revealed principally 2 radiological aspects: hemorrhagic effusion and tumor mass. The pathophysiology of dural metastases is still a subject of debate. Two mechanisms have been put forward involving venous and arterial dissemination. As radiological aspects are confusing, the diagnosis of dural metastasis should be evoked in patients with spontaneous hemorrhagic subdural effusion or a tumor mass involving the dura mater.

Diagnosis, Differential↗

PubMed1998

Endolymphatic sac tumors: report of three cases.

OBJECTIVE AND IMPORTANCE: We present three cases of endolymphatic sac tumors and review the previously published cases. Despite frequent extension to the cerebellopontine angle, these rare tumors have only recently been recognized by neurosurgeons. CLINICAL PRESENTATION: A 26-year-old man developed a progressive hearing loss, revealing an intrapetrous retrolabyrinthine tumor on the right side. A 28-year-old woman experienced a left cerebellopontine angle syndrome, with a lytic intrapetrous mass extending into the cerebellopontine angle. A 38-year-old woman presented with an intracranial hypertension syndrome caused by a tumor of the jugular foramen. INTERVENTION: For the first and second patients, the tumors originated from the operculum of the endolymphatic sac. Total removal was achieved, via a transpetrosal approach, in these two cases. No recurrence was detected after a 20-month follow-up period. For the third patient, the tumor originated from the distal part of the sac. Recurrence was observed 8 years after subtotal removal via a retrosigmoid route. Histological analysis revealed a papillary-cystic adenocarcinomatous pattern in all cases, without features of aggressiveness. CONCLUSION: Endolymphatic sac tumors are locally invasive neoplasms characterized by bipolar intrapetrous and posterior fossa involvement. The anatomic complexity of the endolymphatic sac may explain the distinct patterns of extension of these tumors. Early radical surgery is related to good outcomes.

Adenocarcinoma, Papillary↗

PubMed1998

Preservation of hearing in acoustic neuromas treated by gamma knife surgery.

138 acoustic schwannomas were treated by Gamma Knife surgery from July 1992 to May 1994. Cases with neurofibromatosis were excluded because of differences in the patterns of growth and development of tumors in these cases. Hearing was evaluated by tonal and vocal audiometry and classified using the Gardner and Robertson score. 104 patients were observed at 3 years after treatment. Hearing studies, the relation of tumor volume to hearing, central and marginal dose, number of shots and preoperative brain-stem-evoked responses (BER) were all recorded. 70% of patients with normal hearing maintained a useful hearing, and 50% of patients with useful hearing maintained serviceable hearing. No correlation was found between hearing preservation and tumor volume, central and marginal dose and number of shots. Gamma Knife surgery seems to be superior to microsurgery with regard to preservation of useful hearing.

Audiometry↗

PubMed1997

Expression of cell adhesion molecules in normal nerves, chronic axonal neuropathies and Schwann cell tumors.

Cell adhesion molecules (CAMs) play a role in the normal development and regeneration of tissues as well as in the biological behaviour of tumors. We studied the immunohistochemical expression of various CAMs, such as neural cell adhesion molecule (NCAM), its polysialylated isoform (PSA-NCAM), epithelial (E-) cadherin, and beta1 integrins (alpha2beta1, alpha5beta1, alpha6beta1) in a series of frozen specimens of 10 normal nerves, 5 axonal neuropathies, 26 benign Schwannomas and 2 malignant peripheral nerve sheath tumors (MNST). NCAM was expressed by non-myelinating Schwann cells from normal nerves and overexpressed by Schwann cells from patients with chronic axonal neuropathies and Schwannomas. The expression was lower in MNST. Expression of PSA-NCAM was heterogeneously displayed by Schwann cells from the various tissues studied. Anti E-cadherin immunoreactivity was present in myelin sheath in normal nerves and axonopathies. It was expressed in some Schwannomas especially in vestibular Schwannomas. Integrins VLA alpha2 and VLA alpha6 were widely expressed by Schwann cells from normal nerves, axonal neuropathies and Schwannomas but their expression was low in MNST. VLA alpha5 was not expressed by Schwann cells from normal nerve and Schwannomas but present in chronic axonal neuropathies and MNST. In addition VLA alpha6 was strongly expressed by perineurial cells. These data show that CAMs have a characteristic pattern of expression in normal nerve. Also, some CAMs are always expressed by Schwann cells but the expression of others differs in normal nerves versus axonopathies or tumors, suggesting a role of the microcellular environment in the regulation of CAM expression. Schwannomas have different pattern of expression than MNST.

Axons↗

PubMed1997

[Primary spinal osteosarcomas].

The rarity of primary osteosarcoma of the spine led us to index the 66 reported cases published in literature. From this analysis a difference was found between spinal osteosarcoma and osteosarcoma of the extremities. Tumors of the spine appear to be two times more frequent in the male population in their thirties. The average period between the beginning of the symptoms and the first consultation is seven months. Back pain is permanent and localized to the affected vertebra. In 80 percent of the cases, neurological symptoms already exist at the stage of the diagnosis. Magnetic resonance imaging (MRI), computed tomography and standard X-ray remain complementary in the morphological analysis of this tumor. All the aspects from the lytic to sclerotic forms are noted, although the lytic form is common. Among spinal osteosarcoma, the lumbar vertebrae are the most frequently affected. Diagnosis can only be established by pathology, even though this may also lead to some errors. In all the reported cases surgery is used, but carcinological methodology is not possible and a complete removal of affected tissue is difficult, with this being achieved in only a quarter of the cases. Radiation therapy, when used, requires doses of 70 Gy to 80 Gy without any certitude of controlling the tumour and with high risks of post-radiation complications. Chemotherapy on its own, despite the use of high-dose methotrexate, only has a temporary effect due to partial action on the primary center. Twenty years ago, only twenty percent of all patients suffering from osteosarcoma lived beyond two years, with worse prognosis for spinal osteogenic sarcoma. Today, the therapeutic approach for spinal tumors uses techniques developed in the treatment of osteosarcoma of the extremities, which can now expect more than seventy percent of all patients to live beyond five years. Present day methods recommend a rapid confirmation of the diagnosis, and then a neoadjuvant chemotherapy followed by surgery to remove all the affected area. This strategy allows an evaluation of the tumor chemosensitivity and to adapt the treatment in consequence. The latest results of this treatment on spinal osteosarcoma appear to be encouraging.

Humans↗

PubMed1997

[Primary spinal osteosarcoma. Apropos of a case].

We report a case of primary osteogenic sarcoma of the third lumbar vertebra, detailing the neuroradiologic and therapeutic aspects. The clinical presentation was limited to low back pain which radiated to the left thigh for 5 months. Lumbosacral spine roentgenograms revealed a sclerotic lesion of the left part of the body of the third lumbar vertebra. Treatment consisted of total vertebrectomy, chemotherapy completed with radiotherapy. Fourteen months after a complex combined treatment no recurrence was observed. A review of the literature highlighted the rarity of this tumor. Usually, patients with vertebral osteogenic sarcoma do poorly. Today, the therapeutic approach for these spinal tumors should use techniques developed in the treatment of osteosarcoma of the extremities because of their encouraging results.

Adult↗

PubMed1997

[Acoustico-facial cavernomas. Apropos of 2 surgically treated cases].

BACKGROUND: Acousticofacial cavernomas are rare lesions. Only 4 cases with a cerebellopontine extension have been reported previously whereas intrapetrous facial nerve cavernomas are well described in the otologic literature. In this paper, we describe two additional cases of acousticofacial cavernomas. METHOD AND RESULTS: The two patients were operated via a translabyrinthine route with a preoperative diagnosis of vestibular schwannoma. In the first case, the lesion was confined in the internal auditory canal whereas the cavernoma extended into the cerebellopontine angle in the latter. CONCLUSIONS: Diagnosis is suspected when facial nerve deficit strikingly reveals a small cerebellopontine angle lesion. MRI examination is not specific enough when the lesion is confined to the internal auditory canal. Treatment is based upon surgical removal although facial nerve impairment is often described as the main cause of postoperative morbidity.

Adult↗

PubMed1996

Cervical interbody xenograft with plate fixation: evaluation of fusion after 7 years of use in post-traumatic discoligamentous instability.

STUDY DESIGN: This retrospective study analyzed clinical and radiologic follow-up evaluations of cervical arthrodesis where interbody xenograft combined with internal fixation was used for management of post-traumatic discoligamentous instability. OBJECTIVES: To report results of use of xenograft to avoid the various disadvantages linked to the use of autologous or allogenous bone graft. SUMMARY OF BACKGROUND DATA: Ligamentous instability of the cervical spine is unlikely to heal in a high proportion of cases, and surgical arthrodesis is usually indicated. Anterior arthrodesis has proved to be a safe procedure, but many problems are associated with the use of autograft or allograft. Given the great number of xenograft procedures, there are relatively few reports in the literature. METHODS: A retrospective study analyzed a consecutive series of 52 patients presenting with post-traumatic discoligamentous instability of the cervical spine in which cervical interbody xenografts with plate fixations were done. Follow-up clinical evaluation for neck pain and radiologic evaluation for arthrodesis stability and xenograft fusion at various points in time were done. RESULTS: The long-term results in 41 patients were satisfactory: no infectious complications, extrusion, fracture, loss of height, or resorption of the graft. Seventy-five percent fusion was seen before 9 months after surgery, and 100% fusion was seen 3-18 months after surgery (average, 7.4 months). CONCLUSIONS: Interbody xenograft combined with a rigid plate fixation avoids the problems linked to autologous or allogenous bone graft and gives a safe and solid interbody fusion when arthrodesis is required in ligamentous instability of the cervical spine.

Adolescent↗

PubMed1995

Giant central neurocytoma with tetraventricular and extra-axial extension. Case report.

The central neurocytoma is a recently recognized benign intraventricular tumour of young adults. The authors report a unique case of a panventricular neurocytoma with extension to the interpeduncular and prepontique cisterns which developed in a 35-year-old woman with a 7-year history of headaches and amenorrhea. They review the different pathological and topographical patterns of previously published neurocytomas and discuss the histogenesis of this rare tumour.

Adult↗

PubMed1995

Crowned dens syndrome: a manifestation of hydroxy-apatite rheumatism.

Crowned dens syndrome is defined as an association of acute cervical pain and calcifications in the peri-odontoid space. The authors report one case of this rare localization of hydroxy-apatite rheumatism and review 12 similar cases in the literature. This disease affects only adult females. Patients present with inflammatory signs, can be treated with non-steroid anti-inflammatory drugs and recover without sequela. Calcium pyrophosphate dihydrate deposition can also lead to this syndrome. Other perioodontoid calcifications and ossifications, usually asymptomatic, appear only as a radiologically crowned dens.

Anti-Inflammatory Agents, Non-Steroidal↗