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1.
Clin Radiol ; 79(7): e941-e948, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38710602

ABSTRACT

OBJECTIVES: The popularity of trans-radial access (TRA) for cerebral angiography is growing. Potential benefits of TRA over traditional trans-femoral access (TFA) are multitude. This study aimed to evaluate discharge outcomes and patient opinion of TRA compared to TFA in patients undergoing cerebral angiography prior to stereotactic radiosurgery (SRS) treatment for cerebral arteriovenous malformations. METHODS: Consecutive patients treated at the National Centre for Stereotactic Radiosurgery (Sheffield, United Kingdom) over a 22-month period were included. All patients underwent cerebral angiography with either TRA or TFA as part of treatment planning prior to SRS. TRA patients who had previously undergone TFA in other centres were surveyed for their experience of cerebral angiography using a questionnaire. SRS staff at our centre was approached for their opinion. RESULTS: 492 patients were included (median age = 43 years, 57.5% male, median lesions treated = 1). More patients underwent angiography with TFA (75.2%) than TRA (24.8%). No difference was found in accumulated dose for angiography between the groups (p>0.05). There was 17.6% reduction in overnight stay between TRA and TRF, the proportion of patients requiring overnight admission was higher for the TFA (35.2%) than TRA (17.6%, p<0.05). 101 patients were surveyed, with a response rate of 47%. Most respondents (79%) indicated preference for TRA over TFA. CONCLUSIONS: Use of TRA in pre-SRS cerebral angiography is feasible and improves both patient and staff experience. The adoption of TRA could have important implications for department resources and costs by reducing the proportion of overnight admissions.


Subject(s)
Cerebral Angiography , Intracranial Arteriovenous Malformations , Radiosurgery , Humans , Radiosurgery/methods , Male , Female , Intracranial Arteriovenous Malformations/diagnostic imaging , Intracranial Arteriovenous Malformations/surgery , Adult , Cerebral Angiography/methods , Radial Artery/diagnostic imaging , Middle Aged , Treatment Outcome , Surveys and Questionnaires , Aged , Adolescent , Femoral Artery/diagnostic imaging , Retrospective Studies
2.
Br J Neurosurg ; 19(1): 13-20, 2005 Feb.
Article in English | MEDLINE | ID: mdl-16147577

ABSTRACT

This is a systematic review of a consecutive series of 309 meningiomas treated with gamma knife stereotactic radiosurgery between 1994 and 2000. There was an extreme selection bias towards lesions unfavourable for surgery, determined by the patients referred for treatment: 70% of tumours involved the skull base, 47% specifically the cavernous sinus: 15% of patients had multiple meningiomatosis or type 2 neurofibromatosis. Tumour histology was the main determinant of growth control (p < 0.001), the 5-year actuarial control rates being 87% for typical meningiomas, 49% for atypical tumours and 0% for malignant lesions. Complications from radiosurgery were rare, occurring in 3% of tumours, and were most frequently trigeminal and eye movement disturbances treating cavernous sinus meningiomas. Given the problems inherent in managing these tumours, radiosurgery is a valuable strategy and adjuvant treatment for these meningiomas.


Subject(s)
Meningeal Neoplasms/surgery , Meningioma/surgery , Radiosurgery/methods , Cell Transformation, Neoplastic , Female , Humans , Male , Meningeal Neoplasms/pathology , Meningioma/pathology , Middle Aged , Neoplasm Recurrence, Local , Neoplasms, Multiple Primary/pathology , Neoplasms, Multiple Primary/surgery , Neurofibromatosis 2/surgery , Radiosurgery/adverse effects , Radiosurgery/instrumentation , Reoperation , Tomography, X-Ray Computed/methods , Treatment Outcome
3.
Br J Neurosurg ; 18(4): 338-42, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15702831

ABSTRACT

Haemangioblastomas secondary to von Hippel-Lindau (VHL) disease can be difficult to manage surgically, which has lead to an interest in the use of stereotactic radiosurgery. Retrospectively reviewed here are 30 tumours treated in 14 patients with a mean +/- SD follow-up of 34 +/- 24 months. During this time, three of the 14 patients (21%) died, two of generalized progressive disease. Before radiosurgery, the median time between interventions for cranial haemangioblastomas was 3 years (mean 3.9 +/- 5.0 years). After radiosurgery, the tendency for cranial disease progression was similar, 50% of patients developing further disease by 5 years. Local tumour control was achieved in the majority of cases and estimates of this are included. Radiosurgery is a useful palliative measure controlling the majority of haemangioblastomas, although its efficacy in these patients is limited by the tendency of further disease to develop or progress intracranially.


Subject(s)
Cerebellar Neoplasms/surgery , Hemangioblastoma/surgery , Radiosurgery/instrumentation , Stereotaxic Techniques/instrumentation , von Hippel-Lindau Disease/surgery , Adult , Female , Follow-Up Studies , Humans , Magnetic Resonance Imaging , Male , Neoplasm Recurrence, Local/etiology , Treatment Outcome
4.
Acta Neurochir Suppl ; 91: 55-63, 2004.
Article in English | MEDLINE | ID: mdl-15707026

ABSTRACT

Since its introduction, gamma knife radiosurgery has become an important treatment modality for cerebral arteriovenous malformations. This paper is a brief overview of the technique used, of the clinical results achieved and of the experience gained in Sheffield.


Subject(s)
Arteriovenous Malformations/surgery , Neuronavigation , Radiosurgery , Adolescent , Adult , Aged , Angiography, Digital Subtraction , Arteriovenous Malformations/diagnosis , Cerebral Hemorrhage/etiology , Cerebral Hemorrhage/surgery , Child , Child, Preschool , Cooperative Behavior , Female , Humans , Infant , Male , Middle Aged , Patient Care Team , Patient Selection , Retrospective Studies , Treatment Outcome
5.
J Neurol Neurosurg Psychiatry ; 74(11): 1536-42, 2003 Nov.
Article in English | MEDLINE | ID: mdl-14617712

ABSTRACT

OBJECTIVE: To evaluate the clinical results achievable using current techniques of gamma knife stereotactic radiosurgery to treat sporadic unilateral acoustic neuromas. METHODS: A retrospective review of 234 consecutive patients treated for unilateral acoustic neuromas between 1996 and 1999, with a mean (SD) follow up of 35 (16) months. Tumour control was assessed with serial radiological imaging and by the need for surgical intervention. Hearing preservation was assessed using Gardner-Robertson grades. Details of complications including cranial neuropathies and non-specific vestibulo-cochlear symptoms are included. RESULTS: A tumour control rate in excess of 92% was achieved, with only 3% of patients undergoing surgery after radiosurgery. Results were less good for larger tumours, but control rates of 75% were achieved for 35-45 mm diameter lesions. Of patients with discernible hearing, Gardner-Robertson grades were unchanged in 75%. Facial nerve function was adversely affected in 4.5%, but fewer than 1% of patients had persistent weakness. Trigeminal symptoms improved in 3%, but developed in 5% of patients, being persistent in less than 1.5%. Transient non-specific vestibulo-cochlear symptoms were reported by 13% of patients. CONCLUSIONS: Tumour control rates, while difficult to define, are comparable after radiosurgery with those experienced after surgery. The complications and morbidity after radiosurgery are far less frequent than those encountered after surgery. This, combined with its minimally invasive nature, may make radiosurgery increasingly the treatment of choice for small and medium sized acoustic neuromas.


Subject(s)
Neuroma, Acoustic/surgery , Postoperative Complications , Radiosurgery/methods , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Morbidity , Neuroma, Acoustic/pathology , Retrospective Studies , Treatment Outcome
6.
J Neurol Neurosurg Psychiatry ; 74(9): 1288-93, 2003 Sep.
Article in English | MEDLINE | ID: mdl-12933938

ABSTRACT

OBJECTIVE: To evaluate the results of stereotactic radiosurgery treating vestibular schwannomas secondary to type 2 neurofibromatosis. METHODS: A retrospective review of 122 type 2 neurofibromatosis vestibular schwannomas consecutively treated in 96 patients. Tumour control was assessed by recourse to surgical intervention, by serial radiological imaging, and by the calculation of relative growth ratios in patients (n=29) habouring untreated contralateral tumours to act as internal controls. Hearing function was assessed with Gardner-Robertson grades and with averaged pure tone audiogram thresholds. Other complications are detailed. RESULTS: Applying current techniques, eight years after radiosurgery it was estimated that 20% of patients will have undergone surgery for their tumour, 50% will have radiologically controlled tumours, and in 30% there will be some variable concern about tumour control, but up to that time they will have been managed conservatively. Relative growth ratios one and two years after treatment indicate that radiosurgery confers a significant (p=0.01) advantage over the natural history of the disease. Analysis of these ratios beyond two years was precluded by the need to intervene and radiosurgically treat the contralateral control tumours in more than 50% of the cases. This growth control was achieved with 40% of patients retaining their Gardner-Robertson hearing grades three years after treatment, (40% having some deterioration in grade, 20% becoming deaf). Pure tone audiogram results suggest some progressive long term hearing loss, although interpretation of this is difficult. Facial and trigeminal neuropathy occurred in 5% and 2%. CONCLUSIONS: Radiosurgery is a valuable minimally invasive alternative treatment for these tumours. For most patients, it controls growth or defers the need for surgery, or both. There is a price in terms of hearing function, although this may compare favourably with the deafness associated with the natural history of the disease, and with surgery. In deciding on therapy, patients should be aware of this treatment option.


Subject(s)
Neurofibromatosis 2/complications , Neuroma, Acoustic/etiology , Neuroma, Acoustic/surgery , Radiosurgery/methods , Adolescent , Adult , Audiometry , Child , Deafness/etiology , Deafness/prevention & control , Female , Hearing , Humans , Male , Middle Aged , Retrospective Studies , Treatment Outcome
7.
Acta Ophthalmol Scand ; 81(4): 383-8, 2003 Aug.
Article in English | MEDLINE | ID: mdl-12859266

ABSTRACT

PURPOSE: To determine whether metastasis-free survival following stereotactic radiosurgery is comparable with that following enucleation in a cohort of patients with choroidal and ciliary body melanoma. METHODS: This was a non-randomized, retrospective study of 196 patients with uveal melanoma treated between 1990 and 2000. A total of 118 eyes were enucleated and 78 eyes were treated with stereotactic radiosurgery. The following variables were recorded: age and sex of patient; tumour location, volume and height; the presence of retinal detachment, and extrascleral extension. Tumour location was divided into three categories: within the posterior pole; beyond the limits of the posterior pole but not including the ciliary body, and ciliary body location. Analysis of survival time was performed using Kaplan-Meier estimation of survival curves and Cox's proportional hazards regression modelling. RESULTS: The 5-year cumulative metastasis-free survival rate was 51% in the enucleation treatment group compared to 74% in the stereotactic treatment group. However, in the multivariate analysis there was no statistical difference in survival rates between the two treatment groups. The only variables that influenced survival rates were tumour location (p = 0.002), ciliary body tumours with the worst prognosis, and tumour volume (p = 0.001). CONCLUSIONS: Tumour size and location at presentation determined metastasis-free survival. Large ciliary body tumours had the highest risk of metastasis. Metastasis-free survival after stereotactic radiosurgery was comparable to that after enucleation.


Subject(s)
Eye Enucleation , Melanoma/surgery , Neoplasm Recurrence, Local , Radiosurgery , Uveal Neoplasms/surgery , Adult , Aged , Aged, 80 and over , Disease-Free Survival , Female , Humans , Male , Melanoma/mortality , Middle Aged , Proportional Hazards Models , Retrospective Studies , Survival Rate , Uveal Neoplasms/mortality
8.
J Pak Med Assoc ; 53(4): 147-51, 2003 Apr.
Article in English | MEDLINE | ID: mdl-12776899

ABSTRACT

OBJECTIVE: To ascertain the efficacy of stereotactic radiosurgery (gamma knife) for the control of glomus jugulare tumours. METHOD: Between March 1994 and December 1997 we treated eight patients of glomus jugulare tumour with radiosurgery. These patients have been followed for more than four years (range 52 to 97 months). The age of the patients ranged between 32-64 years (mean 53 years). The male: female ratio was 3:5. Three patients had previously undergone surgery and one had unsuccessful embolization. The dose applied to tumour margin ranged between 16-25 Gy (median 25 Gy). Patients were followed up with yearly MRI scans and where possible with cerebral angiography. RESULTS: All patients showed stabilisation of their symptoms following radiosurgery and six improved clinically. Five of these patients showed decrease in the size of lesion seen objectively on radiology, either slight to moderate decrease seen on the MRI scan or reduction in size and vascularity seen on cerebral angiography. The procedure is minimally invasive and none of the patients showed any adverse effect to radiosurgery. CONCLUSION: These results are encouraging but 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.


Subject(s)
Glomus Jugulare Tumor/surgery , Radiosurgery/methods , Adult , Angiography , Dose-Response Relationship, Radiation , Female , Follow-Up Studies , Glomus Jugulare Tumor/diagnostic imaging , Humans , Male , Middle Aged , Minimally Invasive Surgical Procedures/adverse effects , Minimally Invasive Surgical Procedures/methods , Pakistan , Radiation Dosage , Radiosurgery/adverse effects , Retrospective Studies , Risk Assessment , Sampling Studies , Severity of Illness Index , Treatment Outcome
9.
Diabetologia ; 46(7): 934-9, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12819899

ABSTRACT

AIMS/HYPOTHESIS: The pathogenesis of painful diabetic neuropathy remains unknown. As a consequence we still do not have any effective, rational treatments and a greater understanding of the mechanisms is urgently required. Previous studies have shown no consistent morphological differences in the nerves of patients with and without painful neuropathy. The aim of this study was to compare epineurial haemodynamics in patients with chronic painful and painless neuropathy. METHODS: The techniques of microlightguide spectrophotometry and fluorescein angiography were used to measure epineurial intravascular oxygen saturation and blood flow respectively. Eleven patients with painful and eight with painless neuropathy were studied, with the groups matched carefully in terms of severity of neuropathy and diabetes control. RESULTS: Intravascular oxygen saturation was higher in the painful neuropathy group compared to those without pain (median 73.8% vs 67.7%, respectively; p=0.021). Fluorescein rise time was also faster in those with painful symptoms (median 18.3 s vs 53.6 s; p=0.046) indicating higher epineurial blood flow in these subjects. CONCLUSION/INTERPRETATION: These results indicate that there are distinct differences in haemodynamics within the epineurium of the sural nerve in subjects with painful and painless neuropathy. Haemodynamic factors could therefore have an important role in the pathogenesis of neuropathic pain and might offer further insight into potential treatments for this distressing condition.


Subject(s)
Diabetic Neuropathies/physiopathology , Neuralgia/physiopathology , Peroneal Nerve/physiopathology , Sural Nerve/blood supply , Blood Flow Velocity , Diabetes Mellitus, Type 1/physiopathology , Diabetes Mellitus, Type 2/physiopathology , Female , Humans , Male , Middle Aged , Motor Neurons/physiology , Neural Conduction/physiology , Neurons, Afferent/physiology , Oxygen/blood , Regional Blood Flow , Sural Nerve/physiopathology
10.
Br J Neurosurg ; 16(5): 477-82, 2002 Oct.
Article in English | MEDLINE | ID: mdl-12498492

ABSTRACT

Recognizing a change in our workload and variabilities in referral patterns, we reviewed our previous activity from 1994 to 2000 retrospectively and examined prospectively formal referrals to the Unit in 2001. Arteriovenous malformations still constitute 30% of referrals and treatments, although as a proportion of our workload, this has declined. Radiosurgery is increasingly being chosen as a first line treatment for small and moderate-sized acoustic neuromas, although referral rates vary widely, some neuroscience units referring all and others none of their acoustic neuromas at least for a radiosurgical opinion. About 100 meningiomas, mainly skull-base and/or recurrent tumours after previous surgery, are now treated per year. Compared with other units world-wide, very few pituitary adenomas and cerebral metastases are treated. The implications of this are discussed.


Subject(s)
Radiosurgery/statistics & numerical data , Workload , Arteriovenous Malformations/surgery , Humans , Meningeal Neoplasms/surgery , Meningioma/surgery , Neoplasm Metastasis/therapy , Neuroma, Acoustic/surgery , Prospective Studies , Referral and Consultation/trends , Retrospective Studies , Trigeminal Neuralgia/surgery , United Kingdom
11.
Neurosurgery ; 48(5): 973-82; discussion 982-3, 2001 May.
Article in English | MEDLINE | ID: mdl-11334299

ABSTRACT

OBJECTIVE: To investigate the potential of novel magnetic resonance (MR) angiographic techniques for the assessment of cerebral arteriovenous malformations. METHODS: Forty patients who were about to undergo stereotactic radiosurgery were prospectively recruited. Three-dimensional, sliding-slab interleaved ky (SLINKY), time-of-flight acquisition was performed, as was a dynamic MR digital subtraction angiography (DSA) procedure in which single thick slices (6-10 cm) were obtained using a radiofrequency spoiled Fourier-acquired steady-state sequence (1 image/s). Sixty images were acquired, in two or three projections, during passage of a 6- to 10-ml bolus of gadolinium chelate. Subtraction and postprocessing were performed, and images were viewed in an inverted cine mode. SLINKY time-of-flight acquisition was repeated after the administration of gadolinium. Routine stereotactic conventional catheter angiography was performed after MR imaging. All images were assessed (in a blinded randomized manner) for Spetzler-Martin grading and determination of associated vascular pathological features. RESULTS: Forty-one arteriovenous malformations were assessed in 40 patients. Contrast-enhanced (CE) SLINKY MR angiography was the most consistent MR imaging technique, yielding a 95% correlation with the Spetzler-Martin classification defined by conventional catheter angiography; MR DSA exhibited 90% agreement, and SLINKY MR angiography exhibited 81% agreement. CE SLINKY MR angiography provided improved nidus delineation, compared with non-CE SLINKY MR angiography. Dynamic information from MR DSA significantly improved the observation of early-draining veins and associated aneurysms. CONCLUSION: CE SLINKY MR angiographic assessment of cerebral arteriovenous malformations offers significant advantages, compared with the use of non-CE SLINKY MR angiography, including improved nidus demonstration. MR DSA shows promise as a noninvasive method for dynamic angiography but is presently restricted by limitations in both temporal and spatial resolution.


Subject(s)
Cerebral Angiography , Intracranial Arteriovenous Malformations/diagnosis , Magnetic Resonance Angiography/methods , Adult , Aged , Angiography, Digital Subtraction/standards , Cerebral Angiography/standards , Cerebral Veins/diagnostic imaging , Cerebral Veins/pathology , Female , Humans , Intracranial Aneurysm/complications , Intracranial Arteriovenous Malformations/classification , Intracranial Arteriovenous Malformations/complications , Magnetic Resonance Angiography/standards , Male , Middle Aged , Phlebography/standards
12.
J Neurosurg ; 93 Suppl 3: 191-2, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11143246

ABSTRACT

The purpose of this paper was to note a potential source of error in magnetic resonance (MR) imaging. Magnetic resonance images were acquired for stereotactic planning for GKS of a vestibular schwannoma in a female patient. The images were acquired using three-dimensional sequence, which has been shown to produce minimal distortion effects. The images were transferred to the planning workstation, but the coronal images were rejected. By examination of the raw data and reconstruction of sagittal images through the localizer side plate, it was clearly seen that the image of the square localizer system was grossly distorted. The patient was returned to the MR imager for further studies and a metal clasp on her brassiere was identified as the cause of the distortion.


Subject(s)
Imaging, Three-Dimensional , Magnetic Resonance Imaging , Neuroma, Acoustic/surgery , Radiosurgery , Adult , Artifacts , Female , Humans , Neuroma, Acoustic/diagnosis , Quality Assurance, Health Care
13.
J Neurosurg ; 93 Suppl 3: 198-202, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11143248

ABSTRACT

OBJECT: One of the limiting factors in gamma knife radiosurgery is the restriction to one treatment imposed by the fixed stereotactic frame. The ability, in selected cases, to remove the frame and replace it on a subsequent occasion in the same location would facilitate fractionated treatments and provide flexibility in the timing of treatment delivery. It is the purpose of this work to investigate techniques for frame fixation and for essential verification of frame position once it has been reapplied. METHODS: A technique is proposed that requires four surgical self-tapping screws to be inserted into the skull. Aluminum pins are inserted through the frame pillars and are tightened against the head of the screws, providing a firm fixation of the frame. Pin lengths are recorded on gauges to ensure reproducibility of the position. In phantom tests, test objects were localized (using the angiographic localizer) before and after each of five frame removal/reapplications to test the reproducibility of frame position. The mean error in the observed target coordinates was 0.3 mm and the maximum error observed was 0.7 mm, indicating that the frame can be reapplied with some confidence. Repetition of bubble skull measurements has been investigated as a means of verifying that the frame was repositioned correctly; however, reproducibility of patient measurements was found to be poor even when no frame movement had occurred. In contrast, the use of a radiotherapy simulator to obtain repeated lateral and anteroposterior projections of the head was shown to be capable of detecting frame movements of as little as 1 mm. CONCLUSIONS: Using this technique of frame application facilitates the reapplication of the frame with an accuracy of plus or minus 0.7 mm. Bubble measurements are inadequate for the detection of frame movement. Simple techniques in which a radiotherapy simulator is used can verify correct frame placement and indicate frame movements of less than 1 mm.


Subject(s)
Radiosurgery/instrumentation , Stereotaxic Techniques/instrumentation , Bone Screws , Equipment Design , Humans , Phantoms, Imaging , Reproducibility of Results
14.
Chirality ; 11(8): 645-50, 1999.
Article in English | MEDLINE | ID: mdl-10467316

ABSTRACT

Propylisopropyl acetamide (PID), an amide analogue of the major antiepileptic drug valproic acid (VPA), possesses favorable anticonvulsant and CNS properties. PID contains one chiral carbon atom and therefore exists in two enantiomeric forms. The purpose of this work was to synthesize the two PID enantiomers and evaluate their enantiospecific teratogenicity. Enantioselective synthesis of PID enantiomers was achieved by coupling valeroyl chloride with optically pure (4S)- and (4R)-benzyl-2-oxazolidinone chiral auxiliaries. The two oxazolidinone enolates were alkylated with isopropyl triflate, hydrolyzed, and amidated to yield (2R)- and (2S)-PID. These two PID enantiomers were obtained with excellent enantiomeric purity, exceeding 99.4%. Unlike VPA, both (2R)- and (2S)-PID failed to exert teratogenic effects in NMRI mice following a single 3 mmol/kg subcutaneous injection. From this study we can conclude that individual PID enantiomers do not demonstrate stereoselective teratogenicity in NMRI mice. Due to its better anticonvulsant activity than VPA and lack of teratogenicity, PID (in a stereospecific or racemic form) has the potential to become a new antiepileptic and CNS drug.


Subject(s)
Abnormalities, Drug-Induced , Allylisopropylacetamide/analogs & derivatives , Anticonvulsants/chemical synthesis , Allylisopropylacetamide/chemical synthesis , Allylisopropylacetamide/toxicity , Animals , Anticonvulsants/toxicity , Female , Male , Mice , Pregnancy , Stereoisomerism
15.
Diabetologia ; 42(6): 737-42, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10382594

ABSTRACT

AIMS/HYPOTHESIS: Experimental studies have shown that abnormalities of nerve microcirculation are important factors in the pathogenesis of diabetic neuropathy but there have been few clinical studies. We have applied microlightguide spectrophotometry to measure intravascular oxygen saturation (HbO2%) and blood flow in human sural nerve. METHODS: We studied ten patients with mild-moderate sensory motor diabetic neuropathy, nine patients without neuropathy and nine control subjects. We took 300 measurements of oxygen saturation under direct visual control through a 1.9 mm rigid endoscope over three regions of the nerve. Spectrophotometric measurements of nerve fluorescence were taken after an intravenous injection of sodium fluorescein and the rate of increase in nerve fluorescence (rise time) was used as an indicator of nerve blood flow. RESULTS: Nerve oxygen saturation was reduced in patients with neuropathy compared with control subjects (67.1 +/- 2.2% vs 76.7 +/- 2.1%, p = 0.006). Fluorescein rise time was prolonged in patients with neuropathy compared with the control group (48.5 +/- 7.0 s vs 14.0 +/- 3.1 s, p = 0.001) suggesting impaired nerve blood flow. There was a correlation between rise time, nerve oxygen saturation, glycaemic control and sural nerve sensory conduction velocity (p < 0.01). CONCLUSION/INTERPRETATION: The combination of microlight-guide spectrophotometry and micro-endoscopy provides a valuable minimally invasive technique for clinical investigation of nerve microcirculation. We have shown reduced nerve oxygenation and impaired blood flow in diabetic neuropathy and these findings strongly support a central role of microvascular disease in the pathogenesis of diabetic neuropathy.


Subject(s)
Diabetic Neuropathies/diagnosis , Ischemia/diagnosis , Peripheral Nervous System Diseases/diagnosis , Diabetic Neuropathies/complications , Diabetic Neuropathies/pathology , Female , Glycated Hemoglobin/analysis , Hemodynamics , Humans , Ischemia/complications , Male , Middle Aged , Neural Conduction , Oxygen Consumption , Peripheral Nervous System Diseases/pathology , Sural Nerve/blood supply
16.
J Clin Neurosci ; 6(6): 474-6, 1999 Nov.
Article in English | MEDLINE | ID: mdl-18639183

ABSTRACT

Despite the recent resurgence of interest in the use of pallidotomy for the treatment of Parkinson's disease, there remains considerable debate about the optimal lesion site. Although the current understanding of the neural mechanisms underlying Parkinsonism would suggest that the medial pallidum is the logical site for alleviation of symptoms, some surgeons still advocate lesions in the lateral pallidum. We report the case of such a lesion placement verified pathologically, which resulted in exacerbation of akinesia postoperatively. This demonstrates that accurate targeting in the pallidum is critical to avoid exacerbation of symptoms by lesioning the lateral pallidum.

17.
Epilepsy Res ; 30(1): 41-8, 1998 Mar.
Article in English | MEDLINE | ID: mdl-9551843

ABSTRACT

The teratogenic properties of valproic acid (VPA) and its analogues depend to a great extent on their chemical structure. We investigated the structure-teratogenicity relationships of VPA, its structural isomer, valnoctic acid (VCA), and their two amide analogues, valpromide (VPD) and valnoctamide (VCD), respectively. Each substance was injected (3 mmol/kg) in NMRI-mice on the morning of day 8 of gestation. Embryolethality, fetal weight and exencephaly rates were recorded on day 18 of gestation. VPA caused 53% exencephaly, VPD induced 6%, VCA and VCD produced only 1% exencephaly (control values between 0 and 1%). VPA-treated mice also had increased embryolethality rates (52%). There was no significant change of embryolethality in the other treatment groups. Pharmacokinetic studies showed that VCD was eliminated from plasma at a slower rate than VPA. Also, the residual teratogenic activity of VPD was not accounted for by the relatively small amounts of its hydrolysis product VPA. This study indicates that VPD, VCA and VCD were distinctly less teratogenic than VPA. Apparently the amidation of the free carboxylic group and/or methyl-substitution at the beta-position of the carbon chain greatly decreased the teratogenic activity of VPA.


Subject(s)
Abnormalities, Drug-Induced/epidemiology , Amides/toxicity , Anticonvulsants/toxicity , Embryo, Mammalian/pathology , Pentanoic Acids/toxicity , Teratogens , Valproic Acid/analogs & derivatives , Valproic Acid/toxicity , Amides/blood , Animals , Anticonvulsants/blood , Body Weight , Embryo, Mammalian/drug effects , Female , Fetal Death , Mice , Mice, Inbred Strains , Pentanoic Acids/blood , Pregnancy , Valproic Acid/blood
19.
Br J Neurosurg ; 11(6): 520-4, 1997 Dec.
Article in English | MEDLINE | ID: mdl-11013623

ABSTRACT

Four cases of synovial cyst (ganglion) arising from the facet joints of the lumbar spine are reported. A typical presenting feature was exacerbation of pain on standing or walking, mimicking vascular claudication. MRI proved in all four cases to be the definitive investigation and surgery the treatment of choice, producing excellent results.


Subject(s)
Lumbar Vertebrae/surgery , Spinal Diseases/surgery , Synovial Cyst/surgery , Aged , Female , Humans , Lumbar Vertebrae/pathology , Magnetic Resonance Imaging , Male , Middle Aged , Neurologic Examination , Spinal Diseases/diagnosis , Synovial Cyst/diagnosis
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