PubMed Health⌕ Search

Biomedical subjects

W Pellet

Publications and source records attributed to W Pellet.

At least 19 recordsLinked to original sources
PubMed2006

High jugular bulb in the translabyrinthine approach to the cerebellopontine angle: anatomical considerations and surgical management.

BACKGROUND: Evidence of a high jugular bulb position (HJBP) during the translabyrinthine approach may compromise the surgical removal of cerebellopontine angle (CPA) tumours. We report a simple surgical procedure to safely manage this frequent normal variation and comment on various alternative options. METHODS: The translabyrinthine approach included a complete skeletonization of the sigmoid sinus and of the presigmoid dura. A thin eggshell bone was left at the jugular bulb surface. The dome of the jugular bulb was gently dissected from the jugular fossa and gradually retracted downward in a tailored way, allowing the surgeon to drill below the internal auditory meatus. A small piece of bone was wedged over the jugular dome in order to maintain its lowered position. RESULTS: Among 178 consecutive translabyrinthine approaches performed for the removal of large CPA tumors, the use of this procedure was required in 44 cases of HJBP. Excepting minimal venous bleeding easily controlled in several cases, we never observed any complication from this procedure nor failure to expose the inferior compartment of the CPA. CONCLUSIONS: The HJBP can be systematically diagnosed with the preoperative CT-scan using bone window imaging. Our results demonstrate that the described procedure is safe and effective to widen the operative corridor that is required for the exposure of the inferior compartment of the CPA in this anatomical situation.

Adult↗
PubMed2006

[Value of retrolabyrinthine approach for surgical resection of meningiomas inserted around the lateral sinus between the transverse and sigmoid parts].

PURPOSE: To describe the retrolabyrinthine approach for the resection of 9 meningiomas inserted around the lateral sinus between the transverse and sigmoid parts, to discuss the value of this approach compared to the retrosigmoid approach for resection of meningioma in this localization and to review the literature. METHODS: Retrospective study. Between 1988 and 2002, 9 patients (8 female, mean age 50 years) underwent surgery via the retrolabyrinthine approach for resection of meningiomas inserted around the lateral sinus between the transverse and sigmoid parts. RESULTS: Resection was total (8 Simpson I and 1 Simpson II) in all patients. In the early postoperative course, one patient was treated for meningitidis with an LCR leak and one patient present a temporary paresis of the vagus nerve. Mean follow-up was 5 years (6 months-10 years). All patients continued their pre-treatment occupation after surgery. No recurrence was observed. CONCLUSION: Two approaches can be used for resection of meningiomas in this localization. The retrosigmoid approach is a common neurosurgical approach exposure of the cerobellopontine angle. It is practised by most neurosurgeons. Via this approach, the cerebellar lobe must be pushed back so the arteries feeding the tumor are in the operative field at the end of the procedure. For numerous authors the operative field is too narrow. On the other hand, the retrolabyrinthine approach described in 1972 by Hitselberger and Pulec allows exposure of feeding arteries during the first steps of operation, an easier resection of meningioma insertion and better control of the lateral sinus. This approach can be enlarged to the retrosigmoid or the subtemporal anatomic region.

Adult↗
PubMed2004

[Functional outcomes after translabyrinthine approach for vestibular schwannomas].

PURPOSE: The aim of this paper is to present the functional outcomes after translabyrinthine approach (TLA) for vestibular schwannoma (VS). We analyzed data from 95 patients who had undergone surgery on between 1991 and 2001. METHODS: This retrospective study of clinical and radiological data concerned 95 patients operated on by TLA for a unilateral vestibular schwannoma, excluding NF2 patients and those who have been operated on after a gamma-knife treatment. Results were evaluated with at least 2 Years follow-up and compared with recent data in the literature. RESULTS: Complete tumor removal was achieved in 84% of cases. The facial nerve was normal at the end of the operative procedure in 85%. Facial nerve function was evaluated in 90 patients with two Years follow-up: 62% were grade I or II according to the House and Brackmann scale, 21% were grade III and 16.5% grade IV to VI. CSF leakage was noted in 8.4% including rhinorrhea in 4.2%. No deaths occurred during this period. CONCLUSION: The results related here show that TLA is a safe and efficient procedure for the removal of large acoustic neuromas.

Adolescent↗
PubMed2004

[Functional outcomes of radiosurgical treatment of vestibular schwannomas: 1000 successive cases and review of the literature].

RATIONALE: To evaluate the functional results of Gamma Knife surgery of vestibular schwannomas relying on a large and prospective series of consecutive cases. MATERIAL AND METHOD: The first 1000 patients with cerebello-pontine angle schwannomas were consecutively treated by Gamma Knife in Marseille Timone University Hospital between July 1992 and March 2001. Patients without NF2 and or clinico-radiological arguments in favor of a facial origin accounted for a population of 927 patients (414 males, for 513 females) including 843 treated in first intention. In this series the Koos classification was: stage I 77 patients, stage II 520 patients, stage III 287 patients and stage IV 42 patients. The average Volume was 12.7mm3. Haring was usefull (Gardner and Robertson) before radiosurgery in 47% of the patients (subnormal in 20.3%). RESULTS: Tumor control at last follow-up was 97%. Globally, a clinical trigeminal injury was observed in 0.6% of the patients and a facial palsy in 1.3%. There was clearly a decrease of the incidence of neuropathies with time; no facial palsy being reported among the last 258 patients. The rate of functional hearing preservation (Gardner) for patients initially in class I was 77.8% (47.6% for class II) at 3 Years. This rate of functional preservation reached 95% among patients with tinnitus as a first symptom. CONCLUSION: Today, strong evidence surports the superiority of Gamma Knife surgery in term of functional perservation and equal efficacy compared with microsurgical removal. Consequently, radiosurgery must be preferred as a first intention choice for young patients with few symptoms presenting with a small to middle size vestibular schwannomas (Koos I-III).

Aged↗
PubMed2004

[Hydrocephalus and vestibular schwannomas treated by Gamma Knife radiosurgery].

The occurrence of hydrocephalus in association with a vestibular schwannoma (VS) is a well-known phenomenon. It is usually supported, albeit never demonstrated, that radiosurgery increases the risk of hydrocephalus. The purpose of this study is to investigate this Issue in our own series of patients in order to provide more data. Between July 1992 and January 2002, among the 1000 VS that have been treated at the Timone hospital using a Gamma knife, 43 patients displayed a hydrocephalus, 32 of them before the treatment (group A) and 11 of them only after the treatment (group B). It is of note that in both groups, age at the time of treatment (median age of 70 in A & B) and Volume of tumor were comparable and significantly higher than for the whole treated population. Following radiosurgery, 75% of the patients from the group A did not require a shunt whereas all the patients from the group B did, including 3 who also had significant tumor progression requiring surgery. Occurrence of a de novo hydrocephalus was a rare event (1%) that required a shunt early after radiosurgery, at a mean interval of 14.8 Months (4-31). Results from this study suggest that radiosurgery does not significantly increase the risk of hydrocephalus during the natural history of a VS. We can postulate that Gamma Knife radiosurgery might provide a protective influence on hydrocephalus decompensation since the number of preexisting hydrocephalus that necessitated a shunt after the treatment was small. More investigations involving more patients will bring more arguments in the near future.

Adult↗
PubMed2004

[Preserving hearing function after Gamma Knife radiosurgery for unilateral vestibular schwannoma].

OBJECTIVE: The majority of the patients still lose hearing function in spite of the technical advances in microsurgery. We wanted to evaluate preservation of hearing function potential after Gamma Knife Surgery. MATERIAL AND METHOD: In Marseille, we performed 1000 Gamma-Knife procedures for vestibular schwannomas between July 1992 and January 2002. This population included 175 patients undergoing first intention surgery for a unilateral schwannoma with functional preoperative hearing (Gardner and Robertson 1 or 2) who were studied with a follow-up longer than 3 Years. Univariate and multivariate analysis was performed. RESULTS: Numerous parameters significantly influenced the probability of functional hearing preservation at 3 years. The overall rate of preservation was 60%. The main parameters of predictability were limited hearing loss (Gardner and Robertson stage 1 versus 2) before radiosurgery, presence of tinnitus as the initial symptom, young age and the small tumor size. Preservation of functional hearing at 3 years was 77.8% when the patient was initially in stage I, 80% when the patient's first symptom was tinnitus, and 95% when the patient had both. In these patients, the probability of functional preservation at 5 years was 84%. CONCLUSION: We report a large population of patients treated by radiosurgery with initial functional hearing. These results demonstrate that a large percentage of selected patients can preserve functional hearing after Gamma Knife Surgery, their chances of functional preservation being greater than after microsurgery or simple surveillance.

Adolescent↗
PubMed2004

[Surgical management of vestibular schwannomas secondary to type 2 neurofibromatosis].

To evaluate the results of Gamma Knife radiosurgery treating vestibular schwannomas (VS) secondary to type 2 neurofibromatosis (NF2) we reviewed our clinical experience. Among the VS that have been treated between July 1992 and January 2002, we could analyze retrospectively the data of 50 VS from 37 patients. Fourteen patients had the mild phenotype while 23 were affected by the severe form. Before radiosurgery, one or two microsurgery attempts had been undertaken in 16 VS. Tumor Volume ranged from 120 to 14405 mm3 (mean: 3468 mm3) at the time of treatment; 12 tumors were Koos stade 4. Median clinical and radiological follow-up was 62 Months and ranged from 27 to 123 Months. The 5-Year and 10-Year actuarial survival rates without failure justifying tumor removal were 90 and 85% respectively. The 5-Year actuarial survival rate without hearing decreasing was 36% when selecting the cases of useful hearing (Gardner I & II) at the time of treatment. Severe phenotype (p=0.05) and dose (>12 Gy) delivered at the tumor margin (p=0.032) were correlated to hearing deterioration at univariated analysis. Permanent facial neuropathy occurred in 2%. Even though the level of tumor control and hearing preservation is not the same as for sporadic VS, these results show that Gamma Knife radiosurgery is a valuable alternative treatment for VS in NF2 patients. Future orientation of early proactive radiosurgical treatment of intracanalicular VS will probably improve these results.

Adolescent↗
PubMed2004

[Results and indications of gamma knife radiosurgery for large vestibular schwannomas].

Regular treatment of large vestibular schwannomas (VS) is surgical resection of the tumor with attempt of facial nerve preservation. In a very reduced number of tumors, microsurgery is not warranted mainly because of controlateral deafness or the risk of life-threatening open surgery. The purpose of this study was to analyze the results of Gamma Knife radiosurgery delivered for large VS. Between July 1992 and January 2002, we treated 50 patients harboring a large VS defined as a Koos grade IV tumor. Data and follow-up were available for 45 tumors involving 44 patients, including 12 neurofibromatosis type 2. Mean age at the time of treatment was 43,5 (range: 14-84), mean diameter of the tumor in the CPA was 18mm (range: 12-30) and the mean Volume was 4301 mm3 (range: 1340-11405). Gamma knife treatment was undertaken using on average 13.4 isocenters (range: 4-48) and 10.2 Gy at the tumor margin (range: 8-14). Median follow-up was 45.5 Months (from 24 to 108 Months). Tumor control was 69% (interval confidence: 52-83%) and 3 patients had to be operated because of continuous tumor growth. Statistical analysis showed that tumor Volume was correlated to Gamma Knife failure in a uni-and multivariate model (p=0.027). No brain stem complication was observed. No facial nerve deterioration was found and hearing preservation could be obtained at a useful level in 12 out of 20 patients (60%). These results suggest that in a highly selected subgroup of patients with large VS, radiosurgery can be an interesting alternative to open surgery, particularly if hearing preservation is required. Information should be given to the patients that the risk of failure is greater than for small and medium sized VS.

Adolescent↗
PubMed2004

[Surgical removal of unilateral vestibular schwannomas after failed Gamma Knife radiosurgery].

One of the primary criticismes of vestibular schwannoma (VS) radiosurgery is that the risk of surgical morbidity is increased for patients whose tumor progresses after the procedures. We reviewed the French experience of operated patients after failed Gamma Knife radiosurgery. From July 1992 to January 2002, 25 out of the 1000 treated patients underwent another treatment procedure for a gamma knife failure. Excluding the NF2 patients, 21 patients have been operated and the present study shows the data collected for 20 of them. In order to analyze the difficulties observed during the surgery, a questionnaire was filled by the surgeons. The mean interval between radiosurgery and removal was 36 Months, from 10 to 83 Months. The mean increase in Volume was 559% (37 to 3036%, median 160%). Evolution of the Koos grading was found from 8 grade II, 10 grade III et 2 grade IV to 10 grade III and 10 grade IV. Patients have been operated for radiological tumor growth in 7 cases and for clinico-radiological evolution in 13 cases. In 9 cases, the surgeon considered that he had to face unusual difficulties mainly because of adhesion of the tumor to neurovascular structures. Tumor removal was total in 14 cases, near total in 4 cases and subtotal in 2 cases. One case of venous infarction was noticed at the second day following surgery responsible of hemiparesis and aphasia that gradually recovered. At last follow-up examination, facial nerve was normal (House and Brackmann grade I and II) in 10 cases while it was a grade III in 7 cases and grade IV and V in 3 cases. We recommend that the decision for surgical removal of growing vestibular schwannoma after Gamma Knife treatment should be done after a sufficiently long follow-up period. Our results show that the quality of removal and of facial nerve preservation might be impaired by radiosurgery in half of cases. However these results do not support a change in our policy of radiosurgical treatment of small to medium size vestibular schwannoma.

Adult↗
PubMed2004

[Radiosurgery of vestibular schwannomas after microsurgery and combined radio-microsurgery].

Significant morbidity is expected after microsurgery for recurrent or growing residual vestibular schwannoma (VS). In order to avoid this procedure, radiosurgery appeared as an interesting alternative. The purpose of this study is to analyze the results of Gamma Knife radiosurgery in this indication. Between July 1992 and January 2002, 60 patients (including 12 NF2 patients) underwent radiosurgical treatment after one or more attempts of surgical resection (including 27 growing remnant VS and 19 recurrent VS) and could be followed with enough informations, out of 103 patients (10% of the VS population treated during the same period). Mean interval between surgical removal and radiosurgery was 71.5 Months (1.8-127.8 Months). Technical difficulties during the procedure were observed in the 12 cases, mainly due to problems in identifying the target. Median follow-up was 51.6 Months. Four out of 58 patients (7%, confidence interval: 1.9-16.7) were diagnosed as failure. Statistical study failed to find significant parameters influencing failure. Facial and trigeminal nerves were not impaired while one case of severe bulbopontine radio-induced injury leading to a lower cranial nerve deficit was observed. These results show that, in spite of additional difficulties to treat these patients with radiosurgery, this treatment is efficient with acceptable morbidity and can avoid another microsurgical procedure. The strategy of planned combined micro-and radiosurgical treatment of large VS deserves additional investigations to be validated.

Adult↗
PubMed2003

Mixed meningeal and brain plasma-cell granuloma: an example of an unusual evolution.

We report a study of a 22-year-old woman with a plasma-cell granuloma (PCG), a rare intracranial lesion characterized by a non-neoplastic polyclonal proliferation of plasma cells and other mononuclear cells. She presented after a generalized seizure and CT-scan and magnetic resonance images demonstrated a left temporo-basal tumour mass involving both the meningeal layers and the brain parenchyma. Histopathological examination of a biopsy led to the diagnosis of a typical PCG. After a short course of steroid administration, the clinical and radiological features improved and complete regression of the lesion was shown after one year and persisted at four-year follow-up. This dramatic regression of an intracranial PCG shows that neither surgical removal nor radiation therapy is required to treat a broad skull base PCG.

Adult↗
PubMed2003

Relative indications for radiosurgery and microsurgery for acoustic schwannoma.

The physical and biological principles underlying the use of radiosurgery for the treatment of vestibular schwannomas of up to 2.5 cm in diameter are reviewed together with the historical controversies that have surrounded its introduction. The results in terms of mortality, quality of life, preservation of facial movement and hearing, incidence of shunt-dependent hydrocephalus, cancer neogenesis and brain stem damage are compared in the Marseilles series of 600 microsurgical procedures and 830 Gamma knife procedures and with the peer-reviewed literature. The key principles of a steep profile to radiation exposure at the tumour margin, careful topographical planning of the radiation against the tumour shape to minimise the radiation dose to the cranial nerves and brain stem, early tumour swelling, tumour texture and national history of the tumour are analysed. Protocols for the management of unilateral schwannoma, Type II neurofibromatosis (both the Wishart and the Gardner types) and residual/recurrent tumours are presented. In summary, the growth of nearly 97% of vestibular schwannomas (up to 2.5 cm) is arrested by the Gamma knife, the facial nerve is preserved in almost all cases and hearing may be preserved at its pre-operative level in nearly 70% of cases without the complications of microsurgery.

Humans↗
PubMed2003

Gamma knife radiosurgical management of petroclival meningiomas results and indications.

BACKGROUND: Surgical treatment of petroclival meningiomas remains challenging. In order to refine indications for the use of stereotactic radiosurgery in the treatment of these tumours, we retrospectively evaluated our experience in this field. METHODS: Thirty-two patients harboring a petroclival meningioma were treated consecutively using a Gamma knife between December 92 and June 1998. Eight patients underwent radiosurgery after one or more attempted surgical removals and 24 had radiosurgery as the primary treatment. The main symptoms before radiosurgery were cranial nerve palsies, including a sixth nerve deficit in 10 patients and a trigeminal nerve disturbance in 9. All patients underwent a conformal multi-isocentric treatment (mean isocenter's number 8.8) and the dose delivered at the tumour margin ranged from 10 to 15 Gy (mean dose 13 Gy). FINDINGS: The duration of follow-up varied from 24 to 118 months (mean clinical follow-up 56 months, mean radiological follow-up 52.6 months). All 32 patients survived. The tumour volume remained unchanged in 28 patients and decreased slightly in 4. Neurological status worsened permanently in 2 patients with a delayed hemiparesis due to focal pontine infarction. These complications were associated with large meningiomas with vascular involvement and ventral brainstem compression, and occurred at the very early stage of our experience. At last follow-up, preoperative fifth or sixth cranial nerve deficits had improved or recovered in 13 out of 19 patients and any delayed worsening or new cranial nerve deficits were not observed after radiosurgery. CONCLUSIONS: Stereotactic radiosurgery with a Gamma knife provides effective management of small to middle sized petroclival meningiomas and is an alternative to microsurgery. Careful selection of patients and use of major technical refinements should improve the safety of this treatment.

Adult↗
PubMed2002

[Grade I and II vestibular schwannomas: hearing, clinical course. Pre- and postoperative aspects].

We propose a point by point response to the questions raised at this round table concerning the spontaneous and postoperative course of grade I and II vestibular schwannomas, focusing on hearing function. The questions concerning non-operated schwannomas are: For operated schwannomas, the questions are: Spontaneously, 75-80% of these schwannomas progress significantly with a degradation of hearing function in more than half of the cases. We monitor clinical disorders and order routine audiometry and MRI. For us, Gardner and Roberson class A or 1 is truly useful hearing function. Preservation of truly useful hearing function after microsurgery is no better than 10%; satisfactory facial motor function is preserved in 70-80% of the cases with grade I, II, or III schwannomas and in more than 50% for grade IV schwannomas. Incomplete excision to preserve hearing function is compromised by recurrence. We preferably treat the smaller grade I schwannomas by radiosurgery to halt tumor progression and attempt to preserve hearing function.

Adult↗
PubMed2002

[Preservation of hearing function in the radiosurgical treatment of unilateral vestibular schwannomas. Preliminary results].

INTRODUCTION: Preservation of functional hearing can be now attempted during the surgical treatment of a vestibular schwannomas. The probability of functional hearing preservation for each of the neurosurgical approaches is currently under evaluation. We report here a preliminary evaluation of our radiosurgical experience. MATERIAL AND METHOD: In Marseilles, we performed 800 gamma-knife procedures for cochleovestibular schwannomas by between July 1992 and December 2000. These patients were evaluated systematically according to a prospective methodology. We report here the study of the population of 211 patients with unilateral schwannoma and a functional preoperative hearing (Gardner and Robertson 1 or 2) treated as first intention, with a follow-up longer than two years. RESULTS: Hearing was improved with the radiosurgery in 3% of cases with a average gain of 10 decibels. Average loss in decibel on the four main frequencies (500, 1,000, 2,000, 4,000 Hz) was 17 dB. The probability of functional hearing preservation with radio surgery was high: 73%. However, this probability depended on numerous factors related to the patient and to the "operative technique". The main parameters of predictability were limited preoperative tonal loss, Gardner and Robertson stage 1 (versus 2), multiisocentric planning, peripheral dose lower than 13 Gy. So a Gardner and Robertson stage 1 intracanalicular tumor treated in accordance with "the state of the art" with a gamma-knife and a marginal dose inferior to 13 Gy has a probability of functional conservation at 2 years greater than 95%. CONCLUSION: Our results are preliminary and they require the confirmation of a more extensive and more prolonged follow-up. However, the large size of this population and the systematic methodology should help us in determining more precisely the place of radiosurgery and especially to better inform the patients of their chances of hearing preservation according to their individual risk profile.

Follow-Up Studies↗