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J L Caron

Publications and source records attributed to J L Caron.

15 recordsLinked to original sources
PubMed2001

Scalp nerve blocks decrease the severity of pain after craniotomy.

UNLABELLED: Up to 80% of patients report moderate to severe pain after craniotomy. In this study, we assessed the efficacy of scalp block for decreasing postoperative pain in brain surgery. Thirty patients scheduled for supratentorial craniotomy were enrolled. They were randomly divided into two groups: Ropivacaine (scalp block with 20 mL of ropivacaine 0.75%) and Saline (scalp block with 20 mL of saline 0.9%). Anesthesia was standardized. The scalp block was performed after skin closure and before awakening. Postoperative pain was assessed at 4, 8, 12, 16, 20, 24, and 48 h by using a 10-cm visual analog scale. Analgesia was provided with sub- cutaneous codeine as requested by the patient. Average visual analog scale scores were higher in the Saline group as compared with Ropivacaine (3.7 +/- 2.4 vs 2.0 +/- 1.6; P = 0.036). The total dose of codeine did not differ, nor did the duration of time before the first dose of codeine was required in the Ropivacaine (571 +/- 765 min) versus Saline (319 +/- 409 min; P = 0.17) group. In conclusion, we found that postoperative scalp block decreases the severity of pain after craniotomy and that this effect is long lasting, possibly through a preemptive mechanism. IMPLICATIONS: Up to 80% of patients report moderate to severe pain after craniotomy. This randomized double-blinded study demonstrated that ropivacaine scalp block decreases the severity of pain after supratentorial craniotomy.

Adolescent↗
PubMed1998

The integral biologically effective dose to predict brain stem toxicity of hypofractionated stereotactic radiotherapy.

OBJECTIVE: The aim of this work was to develop a parameter for use during fractionated stereotactic radiotherapy treatment planning to aid in the determination of the appropriate treatment volume and fractionation regimen that will minimize risk of late damage to normal tissue. MATERIALS & METHODS: We have used the linear quadratic model to assess the biologically effective dose at the periphery of stereotactic radiotherapy treatment volumes that impinge on the brain stem. This paper reports a retrospective study of 77 patients with malignant and benign intracranial lesions, treated between 1987 and 1995, with the dynamic rotation technique in 6 fractions over a period of 2 weeks, to a total dose of 42 Gy prescribed at the 90% isodose surface. From differential dose-volume histograms, we evaluated biologically effective dose-volume histograms and obtained an integral biologically-effective dose (IBED) in each case. RESULTS: Of the 77 patients in the study, 36 had target volumes positioned so that the brain stem received more than 1% of the prescribed dose, and 4 of these, all treated for meningioma, developed serious late damage involving the brain stem. Other than type of lesion, the only significant variable was the volume of brain stem exposed. An analysis of the IBEDs received by these 36 patients shows evidence of a threshold value for late damage to the brain stem consistent with similar thresholds that have been determined for external beam radiotherapy. CONCLUSION: We have introduced a new parameter, the IBED, that may be used to represent the fractional effective dose to structures such as the brain stem that are partially irradiated with stereotactic dose distributions. The IBED is easily calculated prior to treatment and may be used to determine appropriate treatment volumes and fractionation regimens minimizing possible toxicity to normal tissue.

Adolescent↗
PubMed1997

Radiosurgery and accelerated radiotherapy for patients with glioblastoma.

OBJECTIVE: To assess the feasibility, toxicity, and local control of stereotactic radiosurgery followed by accelerated external beam radiotherapy (AEBR) for patients with glioblastoma multiforme. MATERIALS AND METHODS: Six males and eight females, with a median age of 67.5 years (range 45-78 years), entered the study. Karnofsky performance status was 90 for five, 80 for six, and 60 for three patients. Following surgery, the patients were left with a residual mass 4 cm. Radiosurgery was delivered with a single dose of 20 Gy to the 90% isodose surface corresponding to the contrast-enhancing edge of the tumour. A total AEBR dose of 60 Gy in 30 fractions was delivered using a concomitant boost technique over four weeks. RESULTS: Median survival time was 40 weeks (range 17-80 weeks). Actuarial survivals at 12 and 18 months were 43% and 14%, respectively. The median time to progression was 25 weeks (range 2-77 weeks). One patient developed a seizure on the day of stereotactic radiosurgery. Two patients experienced somnolence at 47 and 67 days post-radiotherapy. Eight patients remained steroid-dependent. Radiological evidence of leukoencephalopathy was observed in one patient, and brain necrosis in two additional patients at 30 and 63 weeks. One of these two patients with brain necrosis developed complete loss of vision in one eye, and decreased vision in the contralateral eye at 63 weeks. CONCLUSION: Stereotactic radiosurgery followed by AEBR was feasible but was associated with late complications. The use of such radiosurgical boost for patients with glioblastoma multiforme should be reserved for those patients entering controlled clinical trials.

Adult↗
PubMed1995

[Brain metastasis. Palliative treatment with radiosurgery].

This is a retrospective review of 52 patients with metastatic brain disease who underwent stereotactic radiosurgery at McGill University in Montreal. The radiosurgical treatment was performed with the dynamic rotation technique in which there is continuous and simultaneous movement of treatment couch and machine gantry of a 10 MV linac. All patients were treated with a single isocenter and a median dose of 1800 cGy was delivered. In 88% of the cases radiosurgery was given after failure from whole brain conventional irradiation. All 52 cases were assessed with brain CT post radiosurgery. The median follow up time was 6 months (range 1-37 months) and the response rate (partial or complete) was 64%. Only 4 patients (7%) developed late complications related to the treatment. These findings are similar to the literature. Stereotactic radiosurgery is a well tolerated, effective and minimally invasive treatment technique which has a high response rate in selected patients with small, well delineated metastatic brain lesion. Its definitive value as a single therapy or combined with whole brain conventional radiotherapy is being studied in prospective and randomized trials.

Adult↗
PubMed1994

Stereotactic external beam irradiation in previously untreated brain tumors in children and adolescents.

Stereotactically guided external beam irradiation may be a useful form of treatment for small, well-circumscribed, but surgically inaccessible, primary brain tumors that are either benign or of low malignant potential. Between March 1988 and December 1991, 10 children and adolescents with previously untreated primary brain tumors were treated with stereotactic external beam irradiation (SEBI) using a linac-based dynamic technique. Eleven lesions were treated in the 10 patients. Treatment was given using a collimator diameter of 1.5-4 cm (median 2 cm). Single fractions of 18, 20, and 25 Gy were used for 3 lesions in 2 patients. A fractionated schedule delivering a median dose of 42 Gy in 6 fractions over 2 weeks was used in the remaining 8 patients. Morbidity related to treatment was minimal. Three patients suffered a temporary worsening of preexisting neurological symptoms and/or signs at 2, 5, and 5 months posttreatment, with subsequent recovery in all. With a median follow up post-SEBI of 17.5 months (range 5-47 months), improvement in neurological findings related to the lesion was noted for 5 treated lesions; 6 remained clinically stable. Seven of the 11 treated lesions improved radiologically, and only 2 showed evidence of progressive disease. Stereotactic external beam irradiation represents a potentially valuable therapeutic option for selected primary brain tumors in the pediatric and adolescent age group. Morbidity related to the treatment appears acceptable in frequency and type, and preliminary data with regard to response are encouraging. However, in order to assess the impact of such treatment on long-term tumor control and survival, further experience with a larger cohort of patients followed for a longer period of time will be necessary.

Adolescent↗
PubMed1993

A technique for fractionated stereotactic radiotherapy in the treatment of intracranial tumors.

PURPOSE: The excellent treatment results obtained with traditional radiosurgery have stimulated attempts to broaden the range of intracranial disorders treated with radiosurgical techniques. For major users of radiosurgery this resulted in a gradual shift from treating vascular diseases in a single session to treating small, well delineated primary tumors on a fractionated basis. In this paper we present the technique currently used in Montreal for the fractionated stereotactic radiotherapy of selected intracranial lesions. METHODS AND MATERIALS: The regimen of six fractions given every other day has been in use for "fractionated stereotactic radiotherapy" in our center for the past 5 years. Our current irradiation technique, however, evolved from our initial method of using the stereotactic frame for target localization and first treatment, and a "halo-ring" with tattoo skin marks for the subsequent treatments. Recently, we developed a more precise irradiation technique, based on an in-house-built stereotactic frame which is left attached to the patient's skull for the duration of the fractionated regimen. Patients are treated with the stereotactic dynamic rotation technique on a 10 MV linear accelerator (linac). RESULTS: In preparation for the first treatment, the stereotactic frame is attached to the patient's skull and the coordinates of the target center are determined. The dose distribution is then calculated, the target coordinates are marked onto a Lucite target localization box, and the patient is placed into the treatment position on the linac with the help of laser positioning devices. The Lucite target localization box is then removed, the target information is tattooed on the patient's skin, and the patient is given the first treatment. The tattoo marks in conjunction with the target information on the Lucite target localization box are used for patient set-up on the linac for the subsequent 5 treatments. The location of the target center is marked with radio-opaque markers on the target localization box and verified with a computerized tomography scanner prior to the second treatment. The same verification is done prior to other treatments when the target center indicated by the target localization box disagrees with that indicated by the tattoo marks. The new position of the target center is then determined and used for treatment positioning. CONCLUSION: The in-house-built frame is inexpensive and easily left attached to the patient's skull for the 12 day duration of the fractionated regimen. Positioning with the Lucite target localization box verified with tattoo marks ensures a high level of precision for individual fractionated treatments.

Brain Neoplasms↗
PubMed1993

A halo-ring technique for fractionated stereotactic radiotherapy.

Stereotactic radiosurgery has become established as an effective treatment modality for certain non-malignant brain diseases such as arteriovenous malformations. This paper describes an extension of our linear accelerator-based radiosurgical technique to fractionated treatment of intracranial disease. The fractionated stereotactic radiotherapy technique expands the use of the modality by sparing normal cells within the treatment volume thus improving the therapeutic ratio. The first treatment is given using a stereotactic frame both for target localization and patient immobilization. The frame is then removed and subsequent treatments use a standard neurosurgical halo-ring for patient immobilization. The halo-ring is left in place on the skull for the duration of the course of treatment. Thus the physical requirements for fractionation pertain firstly to the patient immobilization and target localization using the halo-ring and secondly to the stringent quality assurance procedures required to maintain spatial accuracy under these new conditions. We describe a sensitive and effective technique for checking the rotational beam parameters and collimator alignment which we use immediately prior to treatment to ensure adequate accuracy of dose delivery to the target volume.

Equipment Design↗
PubMed1993

Early and late complications following dynamic stereotactic radiosurgery and fractionated stereotactic radiotherapy.

Between December 1986 and June 1990, 112 patients (116 lesions), underwent treatment with dynamic stereotactic radiosurgery at McGill University. Of the treated lesions, 59 were arteriovenous malformations and 53 were a variety of other neoplastic conditions. In 86 lesions, the treatment was delivered in a single fraction and the treatment of the remaining 30 lesions was fractionated. Complications attributed to treatment developed in seven of the 112 patients (6.3%). No relationship was found between complications and prescribed dose, fractionation, collimator diameter, type and anatomical region of the lesion that was treated, or previous irradiation. Although extensive clinical experience will be necessary to determine optimal total doses, the potential role of fractionated treatment, and the tolerance of critical structures to radiosurgery, the relatively low incidence of complications in our series allows us to conclude that radiosurgery is well tolerated by the vast majority of patients.

Adolescent↗
PubMed1992

Dynamic stereotactic radiosurgery in the palliative treatment of cerebral metastatic tumors.

From October 1988 to April 1990, 9 patients with metastatic brain disease (11 lesions) underwent stereotactic radiosurgery. All patients but two had recurrent metastatic disease after previous brain irradiation. The patients were treated with a single dose of 20 Gy, delivered to spherical target volumes ranging in diameters from 10 mm to 30 mm and prescribed to the 90% isodose surface. All tumors treated showed a favorable response to the treatment, with 4 patients achieving a complete radiological disappearance of the tumor. The majority of the patients experienced a rapid clinical improvement of their symptoms. No complications attributable to the radiosurgical treatment were seen. Stereotactic radiosurgery appears to be an effective and safe treatment for patients with recurrent metastatic brain disease.

Adult↗
PubMed1992

Photon radiosurgery: a clinical review.

The term radiosurgery has been used to describe a variety of radiotherapy techniques which deliver high doses of radiation to small, stereotactically defined intracranial targets in such a way that the dose fall-off outside the targeted volume is very sharp. Proton, charged particle, gamma unit, and linear accelerator-based techniques appear to be equivalent from the standpoint of accuracy, dose distributions, and clinical results. However, capital and operating costs associated with the use of linear accelerators in general clinical use are much lower. Radiosurgery has an established role in the treatment of arteriovenous malformations and acoustic neurinomas. Interest in these techniques is increasing in neurosurgical and radiation oncological communities, as radiosurgery is rapidly assuming a place in the management of several other conditions, including craniopharyngiomas, meningiomas, and selected malignant lesions.

Humans↗
PubMed1985

Meningioma cysts.

We studied six cases of intracranial meningioma with cyst formation. Manifestations included focal neurologic signs (four cases), seizures (three cases), headache (three cases), and personality changes (two cases). CT revealed a cystic enhancing supratentorial lesion in five cases. Angiographic changes of meningioma were observed in only three cases, and correct preoperative diagnosis was made in only half the cases so studied. Histologically, all lesions were syncytial meningiomas. Cyst fluid was always xanthochromic, acellular, and highly proteinaceous. The variety of anatomic configurations suggests several pathophysiologic mechanisms in formation of the cysts that are commonly misdiagnosed preoperatively. Tissue analysis is needed for all cystic, enhancing lesions of the brain.

Adult↗
PubMed1985

Tension pneumocephalus after evacuation of chronic subdural hematoma and subsequent treatment with continuous lumbar subarachnoid infusion and craniostomy drainage.

We present a case of tension pneumocephalus after burr hole evacuation of bilateral chronic subdural hematomas. Subsequent treatment was effected with combined twist drill closed system drainage and continuous intrathecal infusion of a physiological solution. The clinical entity, tension pneumocephalus, and the use of continuous subarachnoid infusion and drainage as a method of cerebral reexpansion are discussed.

Aged↗