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Biomedical subjects

J C Maroon

Publications and source records attributed to J C Maroon.

At least 55 records · Page 3Linked to original sources
PubMed1992

Methylprednisolone or naloxone treatment after acute spinal cord injury: 1-year follow-up data. Results of the second National Acute Spinal Cord Injury Study.

The 1-year follow-up data of a multicenter randomized controlled trial of methylprednisolone (30 mg/kg bolus and 5.4 mg/kg/hr for 23 hours) or naloxone (5.4 mg/kg bolus and 4.0 mg/kg/hr for 23 hours) treatment for acute spinal cord injury are reported and compared with placebo results. In patients treated with methylprednisolone within 8 hours of injury, increased recovery of neurological function was seen at 6 weeks and at 6 months and continued to be observed 1 year after injury. For motor function, this difference was statistically significant (p = 0.030), and was found in patients with total sensory and motor loss in the emergency room (p = 0.019) and in those with some preservation of motor and sensory function (p = 0.024). Naloxone-treated patients did not show significantly greater recovery. Patients treated after 8 hours of injury recovered less motor function if receiving methylprednisolone (p = 0.08) or naloxone (p = 0.10) as compared with those given placebo. Complication and mortality rates were similar in either group of treated patients as compared with the placebo group. The authors conclude that treatment with the study dose of methylprednisolone is indicated for acute spinal cord trauma, but only if it can be started within 8 hours of injury.

Acute Disease↗
PubMed1992

Blood substitution: an experimental study.

Priming fluids for cardiopulmonary bypass have been extremely varied, with resultant hemodilution. Furthermore, major surgeries utilizing cardiopulmonary bypass require multiple postoperative transfusions of blood and blood products. The appeal of having a readily available blood substitute for major cardiovascular and neurosurgical operations could prove to be a life saver, while also eliminating the risk of diseases transmitted by transfusion. Blood substitutes could also lessen the reported complications resulting from blood damage due to prolonged circulation of the blood by the extracorporeal pump. A technique was examined in 15 dogs using hypothermia for maximum metabolic suppression, incorporating an aqueous blood substitute (Cryomedical Sciences, Inc., Rockville, MD). The anesthetized animals were cannulated for extracorporeal pump oxygenation. As temperature was lowered the dogs were exsanguinated and volume replaced with blood substitute to lower the hematocrit to less than 1%. After 3 hours of cardiac arrest and continuous perfusion at a core temperature less than 10 degrees C, rewarming began. When temperature reached greater than or equal to 10 degrees C, the blood substitute was drained and the animals were autotransfused. The heart was started at 15 degrees C and spontaneous respiration resumed at 29 degrees C. Using the first generation blood substitute the survival rate was maximal (100%) at 2.5 hrs under 10 degrees C and 3 hours of cardiac arrest. Research is underway on a new blood substitute, which is to serve as a universal hypothermic preservation solution (in situ organ preservation).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Lumbar surgery in the elderly.

By virtue of modern neuroimaging, neurosurgeons are increasingly confronted by patients once deemed too old for lumbar corrective procedures. Management of these patients is problematic, as the literature is relatively mute in regard to results and complications within this elderly cohort. We, therefore, reviewed all surgical procedures for benign lumbar disease at two large metropolitan hospitals from January 1986 to June 1988 for patients greater than or equal to 70 years of age. There were 155 procedures performed on 143 patients (male:female, 48:95); the average age of the patients was 74.9 +/- 8.8 years; there were 32 cases of herniated disc, 29 cases of disc plus hypertrophic ligament/bone, and 94 cases of lateral recess/stenosis alone. Hospital stay averaged 7.5 +/- 3.5 days, and increasing age did not correlate with an extended admission. Major morbidity was low (6.9%), and there were no deaths. At follow-up, an average of 34.3 +/- 12.2 months postoperatively, 66.6% (56 of 84) of the patients reported no or minimal discomfort, whereas 15.4% (13 of 84) had not improved at all. Overall, 77.3% (65/84) were pleased with their procedure. These data represent the most comprehensive review in the literature of lumbar procedures in the elderly and indicate that these operations may be undertaken in this population with acceptable morbidity and a reasonable expectation of clinical improvement.

Aged↗
PubMed1991

The relationship between survival and the extent of the resection in patients with supratentorial malignant gliomas.

Current neurosurgical opinion favors the radical surgical removal of supratentorial gliomas, when feasible, in the belief that this optimizes patient survival. Although bolstered by the results of some early investigators, the efficacy of this approach remains debatable. Therefore, we undertook a review of the English language literature of the past 30 years for a series of surgically treated malignant gliomas. Twenty reports comprising 5691 patients were identified. Only 4 found the extent of the surgical resection related to survival. In 2 of these, it followed age, histological findings, and performance status in importance. The 2 other studies did not rank the prognostic variables at all. On closer inspection, however, there does appear to be a subgroup of young patients with favorable histological findings and good performance status for whom surgery is beneficial. Future reporting of surgical results of patients with gliomas will require stratification by the known prognostic variables of age, histological findings, and performance status to characterize better this subgroup for whom surgery is beneficial.

Age Factors↗
PubMed1991

Ultraprofound hypothermia with complete blood substitution in a canine model.

The potential for hypothermia to prevent or ameliorate ischemic injury to the central nervous system is well known. To determine if a more prolonged period of metabolic suppression with blood substitution is possible, a method was developed to lower body temperature to near the freezing point. Eight adult mongrel dogs underwent closed-chest extracorporeal circulation with both external and internal body cooling. As they were cooled, progressive hemodilution was employed until complete exsanguination and blood substitution with an aqueous solution was accomplished. Continuous circulation and a core temperature at a mean of 1.7 degrees C were maintained from 2 1/2 to 3 hours. After rewarming to 20 degrees C, the animals were autotransfused and allowed to recover. Of the eight animals, two died due to technical factors related to cardiac defibrillation. Of the six surviving animals, five survived over a long period and one died on the 10th postoperative day with hepatorenal failure resulting from a presumed blood transfusion incompatability reaction. All six showed normal neurological function and kennel behavior, except one dog with mild weakness of a hindlimb. When the dogs were sacrificed 1 to 2 months postoperatively, all organs were histologically normal. Specifically, there was no gross or microscopic evidence of ischemic or hypoxic injury to any central nervous system structures. This pilot study demonstrates that it is possible to successfully achieve complete exsanguination, blood substitution, and ultraprofound body temperature, while continuous circulation of the blood substitute is maintained. With the capability of controlling and repeatedly performing washout of the extracellular environment and by reaching lower temperatures, it may be possible to attain greater cellular metabolic suppression. This perhaps will extend the allowable times for circulatory arrest procedures. In addition, "bloodless ischemia" may be beneficial in removing both blood substances and formed elements which may mediate organ ischemia. With replacement of blood at warm temperatures, coagulopathy is avoided. This preliminary evidence demonstrates potential in the combination of ultraprofound hypothermia and complete blood component substitution. However, further study is required to confirm the potential of achieving circulatory arrest of longer duration.

Animals↗
PubMed1990

Diagnosis and microsurgical approach to far-lateral disc herniation in the lumbar spine.

Lumbar-disc herniations that occur beneath or far lateral to the intervertebral facet joint are increasingly recognized as a cause of spinal nerve root compression syndromes at the upper lumbar levels. Failure to diagnose and precisely localize these herniations can lead to unsuccessful surgical exploration or exploration of the incorrect interspace. If these herniations are diagnosed, they often cannot be adequately exposed through the typical midline hemilaminectomy approach. Many authors have advocated a partial or complete unilateral facetectomy to expose these herniations, which can lead to vertebral instability or contribute to continued postoperative back pain. The authors present a series of 25 patients who were diagnosed as having far lateral lumbar disc herniations and underwent paramedian microsurgical lumbar-disc excision. Twelve of these were at the L4-5 level, six at the L5-S1 level, and seven at the L3-4 level. In these cases, myelography is uniformly normal and high-quality magnetic resonance images may not be helpful. High-resolution computerized tomography (CT) appears to be the best study, but even this may be negative unless enhanced by performing CT-discography. Discography with enhanced CT is ideally suited to precisely diagnose and localize these far-lateral herniations. The paramedian muscle splitting microsurgical approach was found to be the most direct and favorable anatomical route to herniations lateral to the neural foramen. With this approach, there is no facet destruction and postoperative pain is minimal. Patients were typically discharged on the 3rd or 4th postoperative day. The clinical and radiographic characteristics of far-lateral lumbar-disc herniations are reviewed and the paramedian microsurgical approach is discussed.

Humans↗
PubMed1990

Occult posttraumatic cervical ligamentous instability.

Posttraumatic progressive cervical ligamentous instability and spinal deformity may occur in spite of initially apparently normal spine radiographs. Patients at risk for the development of this problem are generally under 25 years of age and have greater than 1.5 mm of horizontal displacement and greater than 5 degrees of angular displacement on initial cervical roentgenograms. Recent experience with this entity at our institution has led to a reevaluation of the currently existing radiographic criteria for determining ligamentous stability.

Accidents, Traffic↗
PubMed1990

Automated percutaneous discectomy: a prospective multi-institutional study.

A prospective multi-institutional study was carried out to evaluate automated percutaneous discectomy in the treatment of lumbar disc herniations. Of the 327 patients who prospectively met the study criteria and were followed for longer than 1 year, 75.2% were successfully treated. When patients (n = 168) who prospectively did not meet the study criteria were treated, the success rate was 49.4%. One case of discitis was reported; otherwise, no other serious complications were noted, and specifically no vascular or nerve damage was encountered. This study indicates that automated percutaneous discectomy can be used successfully to treat lumbar disc herniations with minimal morbidity and emphasizes the need for proper patient selection.

Humans↗
PubMed1989

Major cerebral vessels injury caused by a seatbelt shoulder strap: case report.

Major cerebral arterial injury may result from penetrating or blunt trauma. In blunt trauma, clinical suspicion of such injury may not be raised, especially if the cranial CT scan is negative. We report a case of a seatbelt shoulder strap to the neck resulting in injury to three major cerebral vessels as demonstrated by cerebral angiography. Although the initial cranial CT scans were negative, a cerebral infarction ultimately developed. The patient was managed conservatively and recovered most of her functions. The importance of clinical suspicion and cerebral angiography is stressed.

Adult↗
PubMed1989

Mechanical aspiration of hematomas in an in vitro model.

A modified Nucleotome (Surgical Dynamics, San Leandro, California) was used to aspirate blood clot in an in vitro model of intracerebral hematoma. This machine was successful in removing the clot at a reasonably rapid rate. It aspirates normal rat brain far more slowly. It therefore shows promise for being effective and safe in removing intracerebral hematomas in humans.

Adult↗
PubMed1989

Effect of intraventricular nadolol infusion on shock-induced aggression in 6-hydroxydopamine-treated rats.

Increasingly, beta blockers are being utilized to treat patients with aggressive disorders secondary to brain lesions. To secure further data about the potential efficacy of beta blockers for this condition, a rat model was employed in which aggression was enhanced by 6-hydroxydopamine. Following lesioning of the brain, aggression in the rats increased from an average baseline of 10.9 +/- 2.1 to 42.7 +/- 2.0 fights per testing period. Thereafter, either pharmacologically inert, artificial CSF or nadolol was introduced through transcerebral, intraventricular perfusion with a significant reduction in aggression in the nadolol-treated animals when compared with those receiving artificial CSF.

Aggression↗
PubMed1989

Head injuries in athletes.

Head injury is a common consequence of athletic participation. Athletes, parents, coaches, trainers, and tem physicians must remain aware that there are potentially significant immediate and long-term effects from both serious and minor head injuries. The recognition of severe and minor head injuries, their immediate management, and guidelines for allowing athletes to return to competition provide the focus for this article.

Athletic Injuries↗
PubMed1989

Management of cervical spine injuries in athletes.

Trauma to the spinal column may cause a variety of clinical syndromes depending on the type and severity of the impact and bony displacement as well as secondary insults such as hemorrhage, ischemia, and edema. Complete spinal cord injury results in a transverse myelopathy, with total loss of spinal function below the level of the lesion. This insult is caused by either anatomic disruption of the spinal cord or hemorrhagic or ischemic injury at the site of injury. Complete injury patterns are rarely reversible, although, with long-term follow-up, improvement of one spinal level may be seen as a result of resolution of initial segmental traumatic cord swelling.

Athletic Injuries↗