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Biomedical subjects

M C Preul

Publications and source records attributed to M C Preul.

28 records · Page 2Linked to original sources

Neurosurgeon as innovator: William V. Cone (1897-1959).

Neurosurgeons are well known for being productive researchers and innovators. Few, however, have possessed the prolific ingenuity of William Cone. In 1934, he and William Penfield were cofounders of the Montreal Neurological Institute where, until 1959, he filled the twin roles of neurosurgeon-in-chief and neuropathologist. Because he did not find writing easy, many of his technical inventions and refinements remained unpublished. His numerous innovations included the extensive use of twist-drill technique for biopsy, drainage for subdural hematoma and cerebral abscess, and ventriculography. In the mid-1940's, he developed power tools driven by nitrogen that led to the modern, universally used air-driven tool systems. He had a special interest in the treatment of spinal dysfunction, for which he invented the Cone-Barton skull-traction tongs along with the Cone spinal operating table. He also devised operative procedures for vertebral fracture-dislocation and craniospinal anomalies. For the maintenance of muscle tone in the paralyzed bladder, he constructed a tidal drainage system. He introduced and popularized ventriculoperitoneal shunting techniques and carried out some of the earliest experimental trails to treat brain infections with sulphonamide and antibiotic drugs. He designed his own set of surgical suction devices, bone rongeurs, and a personal suction "air-conditioning" system for each surgeon. He had a keen early interest in intracranial tumors, and also demonstrated on monkeys how subdural mass lesions caused pupillary dilation and mesial temporal lobe damage due to cerebral compression. His work for the military during World War II on effects of altitude on brain pressure remained classified for many years. The first clipping and excision of an intracranial aneurysm is attributed to Cone. Although Penfield was known as "the Chief," Cone was referred to as "the Boss." His fervent dedication to provide total care to his patients was expressed in round-the-clock vigils; he did not separate "nursing" from "surgical" care. Ultimately, Cone's driving passion for perfection led in part to his tragic death. His accomplishments, inventions, and his example as teacher and physician have become part of neurosurgery's collective legacy.

Canada↗

MRI diagnosis of brainstem cavernous angiomas presenting as tumours.

We report experience with 11 patients misdiagnosed for years, on the basis of computed tomography (CT) and angiography, as harbouring brainstem tumours in whom magnetic resonance imaging (MRI) demonstrated cavernous angiomas. Seven had undergone external irradiation, 2 had a ventriculo-peritoneal shunt, 2 developed aseptic femur necrosis following corticosteroid treatment, 1 had undergone a biopsy with a pathological diagnosis of glioma. CT had depicted ill-defined, hyperdense, faintly enhancing lesions. Angiography was normal, or showed an avascular mass or subtle venous pooling. MRI delineated discrete lesions, typical of cavernous angiomas, with a mixed hyperintense, reticulated, central core surrounded by a hypointense rim. Six patients subsequently underwent stereotactic radiosurgery without changes in clinical status or lesion. Although hemorrhagic neoplasms may mimic the clinical course and MRI appearance of cavernous angiomas, MRI is useful in the diagnosis of brainstem cavernous angiomas and should be performed in patients with suspected brainstem tumours.

Adult↗

Origins of Wilder Penfield's surgical technique. The role of the "Cushing ritual" and influences from the European experience.

Wilder Penfield left two great legacies: the development of successful surgical treatment of epilepsy and the establishment with his colleagues of the Montreal Neurological Institute as a world-renowned medical center, "dedicated to relief of pain and suffering and to the study of neurology." That Harvey Cushing's surgical ritual (which stemmed from the painstaking operative methods of Halsted) played a paramount role in the origins of Penfield's surgical technique is revealed by a set of notes and drawings by Penfield during repeated visits in the 1920's to Cushing's clinic at the Peter Bent Brigham Hospital. Penfield's intellectual approach to the nervous system was derived from his studies with Sherrington. Holmes, Cajal, and Hortega. His eclectic surgical style emerged from his familiarity with the operating techniques of Halsted, Dandy, Horsely, Sargent, Cushing, Frazier, Whipple, Leriche, and Foerster. Penfield's debt to these teachers is documented in his memoirs and in an unpublished report on European neurosurgery which he sent ot the Rockefeller Foundation in 1928.

Epilepsy↗

Autonomic and histopathological effects of percutaneous trigeminal ganglion compression in the rabbit.

The histopathological and autonomic effects of percutaneous trigeminal ganglion compression for trigeminal neuralgia were studied in New Zealand White rabbits. Drops in mean arterial blood pressure of 38% and in heart rate of 30% were observed during compression (p less than 0.0001). Corneal reflex, pinprick sensation, and mastication strength were intact in 13 of 14 rabbits after compression. These findings resembled the effects of percutaneous compression in humans and suggested that the New Zealand White rabbit is a useful model for the study of percutaneous compression. Trigeminal sensory roots and ganglia from 14 rabbits killed at intervals from 1 to 84 days after percutaneous compression were sectioned and stained using immunoperoxidase for neurofilaments, hematoxylin and eosin, luxol fast blue, and cresyl echt violet. Focal axonal damage and demyelination were present 7 days after compression. No difference could be detected in the perikaryonal distribution of neurofilaments between compressed and control trigeminal ganglia. Focal demyelination and Schwann cell proliferation preceding remyelination were present in the trigeminal sensory root at 84 days. Differential injury of axons compared to trigeminal ganglion cell bodies suggests that axonal regeneration is possible and may contribute to the recovery of motor and sensory function in patients after percutaneous compression.

Animals↗

Percutaneous trigeminal ganglion compression for trigeminal neuralgia. Experience in 22 patients and review of the literature.

Between 1983 and 1988, a percutaneous trigeminal ganglion compression (PTGC) procedure for trigeminal neuralgia was performed on 22 patients. All patients were initially relieved of their pain. There were three recurrences (14%); two of these patients underwent a second PTGC procedure and one a partial trigeminal nerve root section. Follow-up examination 3 to 53 months after the procedure showed that all patients were free of pain. Morbidity included persistent minor hypesthesia in five patients, persistent minor dysesthesias in three, persistent minor weakness in three, aseptic meningitis in one, transient sixth nerve palsy in one, and transient otalgia in three. None of the patients had either anesthesia dolorosa or an absent corneal reflex.

Adult↗

Hyperbaric oxygen in the treatment of elevated intracranial pressure after head injury.

This study is the first to evaluate the effect of hyperbaric oxygen (HBO) on elevated intracranial pressure (ICP) after severe head injury during documented controlled ventilation, hypocapnea, and minute-by-minute ICP data collection. We studied the effect of HBO at 2 atmospheres absolute (ATA) with 100% O2, on ICP in 2 patients, aged 5 and 21 years. Each patient had diffuse cerebral swelling after blunt trauma and after a gun shot wound, respectively. Both required controlled hyperventilation, osmotic diuretics and ICP monitoring. ICP, mean arterial blood pressure, pulse and atmospheric pressure were recorded at 1-min intervals during 1-hour treatments and for 15 min before and after HBO therapy. Controlled hyperventilation was continued during HBO therapy and PCO; was measured at intervals. Each patient underwent 4 treatments. Data was divided into 5 phases, all at 100% O2; (1) prior to therapy; (2) during pressurization from 1 to 2 ATA; (3) at 2 ATA; (4) during depressurization from 2 to 1 ATA, and (5) after HBO therapy. During pressurization the mean ICP dropped from 13 to 8 Torr, rising to 14 Torr during HBO therapy at 2 ATA, and to 16 Torr during depressurization to 1 atmosphere, then returning to 12 Torr after HBO therapy. We conclude from this preliminary work that HBO may lower ICP in head-injured patients with diffuse cerebral swelling during the first 15 min, or pressurization phase, of therapy. However, rebound elevations in ICP may occur during or after treatment. No lasting effects of treatment were seen after concluding therapy. The effect of HBO on elevated ICP has not yet been clarified, but deserves further careful study in those patients with severe enough injury to require ICP monitoring.

Adult↗

Trigeminal depressor response during percutaneous microcompression of the trigeminal ganglion for trigeminal neuralgia.

Percutaneous microcompression of the trigeminal ganglion for trigeminal neuralgia was performed 23 times on 21 patients. Significant abrupt drops in heart rate and blood pressure (P less than 0.0002) occurred when the needle entered the foramen ovale or upon balloon advancement or inflation. In 16 of 23 (70%) procedures, the heart rate fell abruptly to 60 or less, by a mean of 38%. Mean arterial blood pressure decreased transiently by 31% during 12 of 23 (55%) procedures. Our findings of transient bradycardia and hypotension upon mechanical stimulation or compression of the mandibular nerve or trigeminal ganglion show for the first time the presence of a trigeminal depressor response in humans. We recommend that heart rate and arterial blood pressure be monitored continuously during percutaneous microcompression of the trigeminal ganglion. Intravenous atropine should be available for immediate use, and an external pacemaker should be fitted preoperatively.

Adult↗

Using pattern analysis of in vivo proton MRSI data to improve the diagnosis and surgical management of patients with brain tumors.

We have used pattern analysis of proton magnetic resonance spectroscopic imaging (1H MRSI) data in a variety of situations related to the clinical management of patients with brain tumors and other cerebral space-occupying lesions (SOLs). Here, we review how 'leave-one-out' linear discriminant analyses (LDAs) of in vivo 1H MRSI spectral patterns have enabled us to quickly, accurately, and non-invasively: (1) discriminate amongst tissue arising from the five most common types of supratentorial tumors found in adults, and (2) use the metabolic heterogeneity of cerebral SOLs to predict certain pathological characteristics that are useful in guiding stereotaxic biopsy and selective tumor resection. These findings suggest that pattern analysis of 1H MRSI data can significantly improve the diagnostic specificity and surgical management of patients with certain cerebral SOLs.

Aged↗