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P V Marks

Publications and source records attributed to P V Marks.

At least 19 recordsLinked to original sources
PubMed2001

Management of spontaneous cerebellar hematomas: a prospective treatment protocol.

OBJECTIVE: To identify easily applicable guidelines for the surgical and conservative management of spontaneous cerebellar hematomas. METHODS: A treatment protocol was developed and prospectively applied for the management of 50 consecutive cases of cerebellar hematomas. The appearance of the fourth ventricle, adjacent to the hematoma, on computed tomographic scans was divided into three grades (normal, compressed, or completely effaced). The degree of fourth ventricular compression was correlated with the size and volume of the hematoma and the presenting Glasgow Coma Scale (GCS) score. The hematoma was surgically evacuated for all patients with Grade III compression and for patients with Grade II compression when the GCS score deteriorated in the absence of untreated hydrocephalus. Patients with Grade I or II compression were initially treated with only ventricular drainage in the presence of hydrocephalus and clinical deterioration. RESULTS: The degree of fourth ventricular compression was classified as Grade I in 6 cases, Grade II in 26, and Grade III in 18. The degree of fourth ventricular compression was significantly correlated with the volume of the hematoma (r(s) = 0.67, P < 0.0001), hydrocephalus (r(s) = 0.44, P = 0.001), the preoperative GCS score (r(s) = 0.43, P = 0.001), the maximal diameter of the hematoma (r(s) = 0.43, P = 0.001), and a midline location of the hematoma (chi(2) = 6.84, P < 0.009). Acute deterioration in GCS scores occurred for 6 (43%) of 14 patients with Grade III ventricular compression who were conscious at presentation. Thirteen patients with Grade I or II ventricular compression and stable GCS scores of more than 13 were treated conservatively. Nine patients were treated with ventricular drainage only, and 28 underwent posterior fossa craniectomy and evacuation of the hematoma with ventricular drainage. The mortality rate at 3 months was 40%. None of the patients with Grade III fourth ventricular compression and GCS scores of less than 8 at the time of treatment experienced good outcomes. Overall, 15 (60%) of 25 patients with hematomas with maximal diameters of more than 3 cm and Grade I or II compression did not require clot evacuation. CONCLUSION: Conscious patients with Grade III fourth ventricular compression should undergo urgent clot evacuation before deterioration. Surgical evacuation of the clot may not be required for large hematomas (>3 cm) if the fourth ventricle is not totally obliterated at the level of the clot.

Adolescent↗
PubMed2000

Effect of photodynamic therapy on recurrent pituitary adenomas: clinical phase I/II trial--an early report.

Pituitary adenomas, although histologically benign, are not always curable by surgery alone, principally because of dural infiltration, as well as their peculiar anatomical location. Radiotherapy has been employed as an adjuvant therapy to address residual disease with favourable results. This approach is, however, not without side effects, and it cannot be repeated. We are therefore investigating the effectiveness of photodynamic therapy (PDT) on recurrent pituitary adenomas in humans. This study details the protocol applied to 12 patients with recurrent pituitary adenomas, which involved systemic administration of photosensitizer (Photofrin) followed, after a period of 24-48 h, by intraoperative illumination of the tumour bed using 630 nm laser light. The primary end points were visual, endocrine and radiological improvement. The incidence of side effects was also monitored. The longest follow-up is 2 years. Most patients suffering from visual acuity or field defects have shown improvement when followed for 12 months or more. Three patients showed complete recovery of their visual fields. All those who presented with functional adenomas have shown reduction in their hormone levels. Tumour volume, relative to the preoperative size, was 122, 87, 66, 60 and 46% at 4 days, and 3, 6, 18 and 24 months, respectively. One patient developed severe skin photosensitization due to early exposure to direct sunlight and three others displayed minor skin reactions. There was no treatment-related mortality or morbidity. One patient (operated transcranially) developed hemiparesis postoperatively, which recovered completely. We think this is unrelated to the treatment. This prospective study demonstrates that PDT may be safely applied to the pituitary fossa by the trans-sphenoidal route and indicates the need for a randomized, controlled trial in order to establish its therapeutic potential.

Adenoma↗
PubMed1998

A preliminary experimental in vivo study of the effect of photodynamic therapy on human pituitary adenoma implanted in mice.

As surgery alone may prove inadequate to effect a cure for invasive pituitary adenomas, photodynamic therapy (PDT) was investigated as a possible adjuvant treatment for this group of tumours. Different subtypes of human pituitary adenoma cells were implanted subcutaneously into nude mice to study the in vivo effect of PDT on such lesions. The photosensitizer used in this study was polyhaematoporphyrin at a dose of 10 mg/kg b.w., followed by light irradiation at a wavelength of 630 nm with varying light doses between 10 and 75 J/cm2. Histopathological examination of the treated implants consistently showed tumour vascular changes with acute inflammatory reaction, interstitial haemorrhage, and evidence of cell death at higher doses of light. These changes were absent in the control groups. These findings indicate that the cytotoxic effect of PDT demonstrated in vitro in previous studies, is also present in vivo.

Adenoma↗
PubMed1997

Muslin induced granuloma following wrapping of intracranial aneurysms: the role of infection as an additional precipitating factor. Report of two cases and review of the literature.

Two patients who developed what appeared to be a granulomatous reaction following muslin wrapping of unclipped aneurysms are reported. They presented with cranial nerve palsies and at operation were found to have an abscess around the wrapped aneurysms. In one of these two patients Staphylococcus epidemidis was isolated from the pus. This, together with further evidence from reported cases in the literature, would suggest that infection may play an additional role at least in some cases in the onset of a foreign-body granulomatous reaction seen following wrapping of aneurysms.

Brain Abscess↗
PubMed1995

Posttraumatic cerebellar infarction.

We report an 18-year-old patient who presented with delayed neurological deterioration secondary to posttraumatic cerebellar infarction. Management by ventricular drainage and posterior fossa decompression resulted in a good outcome. The absence of a demonstrable structural vascular lesion makes this case apparently unique. The possible aetiology, pathogenesis and management of this condition are discussed.

Adolescent↗
PubMed1995

Adjuvant therapy for pituitary adenomas: the possible role of photodynamic therapy.

Although benign, pituitary adenomas may not always be curable by surgery alone. This is usually owing to dural infiltration and the technical problems of removal of involved dura in the sellar region. In such circumstances, some form of adjuvant therapy may be needed to address residual tumour and forestall recurrence. Radiotherapy and drugs, such as bromocriptine or octreotide, although effective are far from ideal adjuvant therapies and this has led to the study of the effects of photodynamic therapy on pituitary adenomas. It has been shown that photodynamic therapy using the photosensitising drugs haematoporphyrin derivative and aluminium phthalocyanine is active experimentally against these tumours. This could provide another useful weapon to use against these challenging lesions.

Adenoma↗
PubMed1994

Undiagnosed epidermoid cyst presenting as trigeminal neuralgia: a need for MRI.

A case of an epidermoid cyst in the cerebello-pontine angle presenting with facial pain is reported. The tumour was discovered during neurovascular decompression of the fifth nerve. A pre-operative CT scan was normal. The role of neuroradiological investigation in young patients with trigeminal neuralgia is discussed.

Adult↗
PubMed1994

Propofol--contrasting effects in movement disorders.

We report two patients presenting for thalamotomy in whom tremor was abolished for 8 h after propofol anaesthesia. Propofol has two contrasting actions. It may have an anti-Parkinsonion effect, abolishing abnormal limb movements. On other occasions, propofol is known to induce spontaneous abnormal limb movements, as well as epileptiform activity. Propofol is probably best avoided for stereotactic procedures. It is difficult to reconcile these two opposing actions.

Anesthesia, Intravenous↗
PubMed1993

Stereotactic surgery for post-traumatic cerebellar syndrome: an analysis of seven cases.

A variety of post-traumatic movement disorders may follow severe head injury. Generally, the movement disorder is a moderate to severe intention tremor, and this is often the major source of disability for the patient. The clinical features of 7 patients whose predominant problem was a post-traumatic cerebellar syndrome, who were treated by stereotactic ablation of the ventralis intermedius thalamic nucleus, are reported. 6 patients had good relief of their tremor and only 1 patient did not improve. Conservative treatment is usually ineffective, but in appropriately selected cases, stereotactic thalamotomy has a high degree of clinical success.

Adolescent↗
PubMed1993

Racial differences between Maori and European New Zealanders in aneurysmal subarachnoid haemorrhage.

Racial differences in the incidence and rate of rupture of intracranial aneurysms are well recognized. A retrospective study of racial differences between Maori and European New Zealanders presenting to the Auckland Regional Neurosurgical Unit between 1985 and 1990 was conducted. It was found that the incidence per 100,000 of the population for all aneurysms was 14.3 for Europeans and 25.7 for Maoris. The mean age at rupture was 10 years earlier in Maoris with single aneurysms. A strong association between aneurysmal subarachnoid haemorrhage and cigarette smoking was found in both groups not only for single, but also for multiple aneurysms. Maoris were also found to have an abnormally high incidence of middle cerebral artery aneurysms and a low incidence of vertebrobasilar ones compared with Europeans.

Adult↗
PubMed1993

In vitro study of the effect of photodynamic therapy on pituitary adenomas.

Photodynamic therapy (PDT) has been employed in the management of recurrent cerebral gliomas, but its activity against pituitary adenomas has not been specifically studied. An in vitro study of the effects of PDT against a variety of pituitary adenomas was conducted. It was found that PDT using haematoporphyrin derivative as a photosensitizer showed dose dependent activity against a variety of pituitary adenomas. The activity of PDT against pituitary adenomas should be investigated further and may hopefully provide a useful form of adjuvant therapy for preventing recurrence of micro-invasive pituitary adenomas or dealing with established recurrence after surgery and radiotherapy.

Adenoma↗
PubMed1992

An in vitro study of the effect of photodynamic therapy on human meningiomas.

Despite being benign CNS tumours, meningiomas are not always curable and the likelihood of recurrence depends upon the completeness of initial removal. Adjuvant therapy for incompletely resected meningiomas is generally unsatisfactory and such lesions continue to pose difficult management problems. Photodynamic therapy (PDT) has been employed in the management of recurrent cerebral gliomas but its activity against meningiomas has not been specifically studied. An in vitro study of the effects of PDT against a variety of meningiomas was therefore conducted. It was found that PDT using haematoporphyrin derivative as a photosensitizing drug showed dose-dependent activity against a variety of histological subtypes of meningioma. The activity of PDT against meningiomas should be investigated further and may eventually provide a useful form of adjuvant therapy for incompletely resected lesions.

Aged↗
PubMed1992

A randomized trial of nimodipine in severe head injury: HIT I. British/Finnish Co-operative Head Injury Trial Group.

We studied the efficacy of nimodipine in severely head-injured patients in a randomized study. Of 176 patients who received nimodipine, 2 mg/h iv for 2 day, 53% had a favorable outcome (moderate or good recovery). Of 175 control patients, 49% had a favorable outcome. This difference was not statistically significant but does not exclude the possibility that a study of a larger number of patients could show a clinically useful benefit.

Adult↗
PubMed1992

Life-threatening glossopharyngeal neuralgia.

Glossopharyngeal neuralgia is a rare condition that, on occasions, may be associated with cardiac dysrhythmia. This case report describes the case of an 86-year-old woman whose glossopharyngeal neuralgia was complicated by life-threatening dysrhythmias and who was cured by posterior fossa rhizotomy.

Aged↗