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Biomedical subjects

D W Rowed

Publications and source records attributed to D W Rowed.

At least 37 records · Page 2Linked to original sources
PubMed1990

Chronic cluster headache managed by nervus intermedius section.

Cluster headache sufferers who become candidates for surgical treatment are those relatively rare patients who are refractory to all attempts at pharmacological relief. Ablative surgical procedures have been directed against either the trigeminal nerve or the nervus intermedius/greater superficial petrosal (NI/GSP) pathway. Both carry nociceptive impulses from the head and face, and the NI also carries parasympathetic fibres which appear to be responsible for the autonomic concomitants of cluster headache. Trigeminal operative procedures are not consistently helpful in chronic cluster headache, while NI section has been shown to give potentially long lasting relief but carries the potential risks of cerebellopontine angle surgery. In eight selected cases of chronic cluster headache we have demonstrated a high early success rate for pain relief, with few complications, in the performance of NI section, combined, when indicated, with microvascular decompression of the trigeminal main sensory root. We believe that cochlear nerve monitoring helps prevent postoperative hearing impairment. An intimate relationship between the NI and arterial loops of the anterior inferior cerebellar artery (AICA) or the internal auditory artery has been frequently observed in our chronic cluster headache patients.

Adult↗
PubMed1990

Somatosensory evoked potentials and neurological grades as predictors of outcome in acute spinal cord injury.

An analysis of Motor Index score, pinprick sensory score, joint position sense score, somatosensory evoked potential (SSEP) grade in the ulnar (SSEPu) and posterior tibial (SSEPt) regions, and overall SSEP grade (mean SSEPu + t) was conducted in 36 patients with cervical spinal cord injuries to determine the relationship of these scores, both individually and in combination, to functional outcome (as determined using the Barthel Index) at 6 months after injury. The clinical and electrophysiological data were obtained on the same day within 2 weeks after injury. Nineteen patients underwent two SSEP tests 1 week apart within the first 3 weeks following injury in an attempt to identify mean SSEPu + t improvement. Somatosensory evoked potential grading was based on the presence or absence of the cortical evoked potential, the amplitude of the early cortically generated waveform (P22 or P37), and the interpeak latency across the lesion site. Mean SSEPu + t had the strongest individual relationship with outcome (R-square 0.75, p less than 0.0001) and mean SSEPu + t improvement over a 1-week interval during the first 3 weeks after injury was associated with Motor Index score improvement over a 6 month period. Joint position sense score was the best clinical predictor of outcome (R-square 0.64, p less than 0.0001). Mean SSEPu + t correlated with outcome more closely than the combination of Motor Index score and pinprick sensory score. Mean SSEPu + t in combination with all three clinical indicators produced the strongest correlation with outcome (R-square 0.87, p less than 0.0001). This study confirms the prognostic value of quantitative SSEP analysis for patients with acute spinal cord injuries.

Acute Disease↗
PubMed1989

Cochlear nerve action potentials during cerebellopontine angle surgery: relationship of latency, amplitude, and threshold measurements to hearing.

The cochlear nerve action potential (AP) was monitored during two types of hearing preservation surgery: (1) removal of small cerebellopontine angle tumors and (2) retrolabyrinthine vestibular nerve section. The purpose of this investigation was to study the relationship between changes in intraoperative AP latency, amplitude, and threshold, and changes in audiometric hearing subsequent to surgery. The presence or absence of a cochlear nerve AP toward the end of surgery accurately predicted the presence or absence of postoperative hearing (93%). Regression analyses were performed to explore the relationship between audiometric pre- and postoperative thresholds and intraoperative AP threshold changes. Statistically significant relationships were found for (1) pre-operative audiometric thresholds and initial AP click thresholds (p = 0.0068); (2) final AP click thresholds and postoperative audiometric thresholds (p = 0.0003); (3) AP click (p = 0.0001) and 1 kHz (p = 0.0006) threshold shifts and pre- to postoperative audiometric threshold shifts. No relationship was found between either AP latency or amplitude values and postoperative hearing. Intraoperative threshold measurements can be used as an indicator of hearing change. If amplitude or latency indices are also monitored it may be better to use stimulus levels close to the evoked potential threshold.

Action Potentials↗
PubMed1988

Cochlear nerve monitoring during cerebellopontine angle operations.

The authors present their experience with intraoperative monitoring of cochlear nerve action potentials (AP) in 30 adult patients. Operative procedures were acoustic neuroma excision with attempted hearing preservation and selective vestibular neurectomy in patients with incapacitating Meniere's disease and serviceable hearing (SRT less than 50 db, discrimination greater than 60%). Loss of AP is detected rapidly and has been demonstrated after manipulation of the cochlear nerve and after coagulation of small arteries on the tumour capsule. Presence of an AP at the end of the procedure usually correlates with postoperative preservation of hearing. AP monitoring appears to be a reliable means of detecting potentially reversible changes in cochlear nerve function intraoperatively.

Action Potentials↗
PubMed1986

Is no treatment good treatment in the management of acoustic neuromas in the elderly?

Two hundred twenty-eight patients with acoustic neuromas were seen between 1974 and 1985. Twenty-eight received no surgical treatment. Five patients who had undergone previous partial excision were excluded. The mean age was 71 years. The mean expected survival was 14.3 years. The mean follow-up interval was 51 months (range 12 to 120 months). All patients underwent at least two CAT scans (mean = 4). Tumor size ranged from 4 mm to 30 mm. Three patients underwent insertion of ventricular-peritoneal shunt for hydrocephalus (mean 16 months after presentation) and two patients partial tumor removal (mean 30 months after presentation). Tumor growth was measured in each patient using CAT scanning. Monitoring by clinical examination and regular CAT scanning is possible, but in this study 20% of patients required surgical treatment within one third of their expected survival time. This suggests that an expectant attitude for this group of patients may be a debatable form of management.

Age Factors↗
PubMed1986

Radiologic assessment of acoustic neuroma in the elderly. Is no treatment good treatment?

Twenty-three elderly patients with acoustic neuroma have been followed conservatively (no treatment) for a mean of 3.8 years. Five patients subsequently required ventricular shunting. Two patients required partial excision of their tumors (one previously treated by shunting). Eleven patients who have required no treatment have no significant complaints. There was significant variation in tumor growth rates making predictability for surgical intervention hazardous. A mean growth rate of 0.22 cm/year was noted. Our statistics suggest tumor removal in healthy patients with larger tumors at time of presentation; in other patients, conservative follow-up may be more appropriate.

Age Factors↗
PubMed1985

Traumatic aneurysm of the posterior inferior cerebellar artery caused by fracture of the clivus.

The authors present a case of traumatic aneurysm of the posterior inferior cerebellar artery produced by fracture of the clivus. Varieties of clival fractures reported in the literature are reviewed. Associated basilar or carotid arterial lesions have been reported, but traumatic aneurysm, so far as we are aware, has not. The authors emphasize the importance of a high index of suspicion of undetected traumatic intracranial aneurysm when an unusual amount of subarachnoid hemorrhage is noted on the initial computed tomographic scan, particularly if associated with displaced basal skull fracture.

Arteries↗
PubMed1985

Transorbital intracavernous needle biopsy in painful ophthalmoplegia. Case report.

Painful ophthalmoplegia due to lesions in the region of the anterior cavernous sinus and superior orbital fissure may elude early diagnosis. Principal disease categories to be considered in patients with this complaint are neoplasm, vascular lesion, and inflammation. Although high-resolution computerized tomography (CT) may be helpful, definitive diagnosis frequently requires histological examination of tissue. In suitable patients this may be obtained by transsphenoidal or orbital biopsy. The orbital fine-needle aspiration technique has been recommended, but experience with this method is limited, and a definitive diagnosis cannot always be reached. The authors have established that, in suitable patients, the fine-needle aspiration technique with CT guidance may also be employed safely and effectively for lesions of the anterior cavernous sinus.

Aged↗
PubMed1985

Subdural meningioma of spinal cord. Case report.

A case of extensive circumferential meningioma of the spinal subdural space is reported. A potential mechanism for this growth pattern is proposed, and preoperative diagnosis by computerized tomography is discussed. This case reinforces the necessity for intradural exploration when an expected extradural neoplasm is not encountered at operation.

Adult↗
PubMed1984

Spinal injuries due to hockey.

Although many types of sports and recreational activities have been identified as common causes of acute spinal cord injury, hockey has been a rare cause of acute cord injury in Canada or elsewhere. For example, from 1948 to 1973 there were no patients with cord injuries due to hockey in a series of 55 patients with acute cord injuries due to sports or other recreational activities admitted to two Toronto hospitals. In contrast, between 1974 and 1981, the Acute Spinal Cord Injury Unit, Sunnybrook Medical Centre treated six patients with cervical spinal injury due to hockey, five of whom were seen during a 13 month period from September, 1980 to October, 1981. Five of the six sustained a severe acute cervical spinal cord injury, and one a cervical root injury. The cord injury was complete in two cases, while three had complete motor loss but incomplete sensory loss below the level of the lesion. All were males aged 15 to 26 years. Of the players with cord injury, four struck the boards with the neck flexed, and one struck another player with the neck flexed. The one player without cord injury struck the boards with his neck extended. The commonest bony injury was a burst fracture of C5 or C6. One of the patients with a complete cord injury died three months later of a pulmonary embolus, and the other patients with cord injury showed some recovery of root function, but little or no cord recovery. The reasons for the increase in spinal injuries in hockey are unknown.

Adolescent↗
PubMed1984

The University of Toronto head injury treatment study: a prospective, randomized comparison of pentobarbital and mannitol.

Fifty-nine patients were treated in a prospective, randomized comparison of pentobarbital and mannitol for the control of intracranial hypertension resulting from head injury. Patients with elevated intracranial pressure (ICP) after evacuation of intracranial hematomas were randomized to one of two treatment groups; mannitol initially or pentobarbital initially, followed by the second drug as required by further elevation of ICP. Similarly, patients with raised ICP but without hematomas requiring evacuation were randomly assigned to two treatment groups in an identical paradigm. Those with ICP elevation and no hematoma treated with pentobarbital as initial therapy had a 77% mortality compared to a 41% mortality for those with mannitol as initial treatment. Patients with evacuated hematomas had mortalities of 40% and 43% (no significant difference) for pentobarbital and mannitol respectively. In both no-hematoma and hematoma streams pentobarbital was less effective than mannitol for control of raised ICP. Multivariable statistical analysis indicates that pentobarbital coma is not better than mannitol for the treatment of intracranial hypertension and may be harmful in no-hematoma patients with intracranial hypertension after head injury.

Adult↗
PubMed1984

Management of acute spinal cord injuries.

This report describes the results achieved in 144 patients with spinal cord injury admitted during the period 1974 to 1979 to the Acute Spinal Cord Injury Unit of Sunnybrook Medical Centre in Toronto. Several innovations have been made. These are based on a systems analysis approach to care and documentation. It includes epidemiologic studies of, and programs for, urologic and respiratory management and the use of halo devices. The unit has achieved a marked reduction in both mortality and morbidity. Patients have been transferred to the unit earlier after trauma and have been discharged earlier to rehabilitation hospitals partly because of the coordination of the acute and rehabilitation phases of care. There has been a marked reduction in the cost of care, because of fewer complications and a shorter stay in the acute hospital. The study confirms the advantages of regionalization and specialization in the field of acute spinal cord injury.

Acute Disease↗
PubMed1982

Favorable results with syringosubarachnoid shunts for treatment of syringomyelia.

From 1969 to 1979, 20 patients with syringomyelia were treated with a syringosubarachnoid shunt. The principal indications for this procedure were: significant progressive neurological deterioration and absent or minimal tonsillar ectopia. There were 15 patients with idiopathic syringomyelia, four with posttraumatic syringomyelia, and one with syringomyelia secondary to spinal arachnoiditis. The operations were performed with an operating microscope, and attention was directed to preserving thearachnoid membrane to ensure proper placement of the distal end of the shunt in an intact subarachnoid space. In all cases, a silicone rubber ventricular catheter was inserted into the syrinx through a posterior midline myelotomy. The average follow-up period was 5 years. A favorable result was obtained in 15 of the 20 patients (75%), including an excellent result with improvement of neurological deficit in 11 patients and a good result with cessation of progression in four patients. In the remaining five patients the result was poor with further progression of neurological deficit. A short duration of preoperative symptoms was usually a favorable prognostic feature. Four patients with a history of less than 6 months all had excellent results. Thirteen patients had a syringosubarachnoid shunt only, and all had good or excellent results. Seven patients had other surgical procedures, before, accompanying, or after shunt placement, and two had favorable results. Thus, the syringosubarachnoid shunt is an effective therapeutic modality for many patients with syringomyelia, particularly if there is little or no tonsillar herniation.

Adult↗
PubMed1981

Intraoperative regional cerebral blood flow during carotid endarterectomy.

Regional cerebral blood flow (rCBF) during internal carotid artery (ICA) occlusion for endarterectomy can be measured without inconvenience using the probe holder illustrated. When mean ipsilateral hemispheric CBF exceeds 20 ml/100 gm/min, an intraluminal bypass is not necessary (63% of patients), except in patients with extensive cerebrovascular disease in whom rCBF should also exceed 20 ml/100 gm/min in all areas. ICA "stump" pressure is falsely high in about 20% of patients, and is therefore not a dependable criterion for selecting patients who need shunting. While intraoperative shunting is capable of restoring pre-occlusion CBF levels, it does not eliminate the risk of intraoperative ischemic neurological deficit of probable embolic origin.

Adult↗
PubMed1979

Current concepts in the immediate management of acute spinal cord injuries.

The management of acute spinal cord injuries has changed considerably during the past 10 years owing to new information about the pathophysiology of cord trauma and new diagnostic and treatment methods. It is now known that the cord suffers not only from the immediate physical effects of trauma, but also from secondary pathologic processes, such as ischemia and edema, which are treatable in the first few hours after injury. New neuroradiologic and neurophysiological techniques, such as the recording of the somatosensory evoked potential, increase the accuracy of diagnosis and prognosis in the acute phase. Current immediate treatment includes the administration of steroids and mannitol, with careful attention to respiratory and cardiovascular homeostasis, to overcome post-traumatic ischemia and edema, and immobilization of the spine with devices such as the halo. New surgical procedures are used in selected cases to improve neurologic recovery, to provide rigid immobilization of the spine or to allow earlier mobilization of the patient. The care of spinal cord injuries in the acute phase is facilitated by multidisciplinary units.

Animals↗
PubMed1978

Somatosensory evoked potentials in acute spinal cord injury: prognostic value.

The somatosensory evoked potential is absent in patients with complete motor and sensory loss below the level of spinal cord injury. When spinal cord injury is incomplete, these alterations in potential may be elicited from stimulation of a nerve entering the cord below the level of injury. The presence of such potentials soon after injury, or their early return, and progressive normalization of the wave form are sensitive early indications of favorable prognosis. Indeed, recovery of the somatosensory evoked potentials frequently precedes major clinical improvement and may occur in advance of clinical recovery or posterior column function.

Adolescent↗