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J C Maroon

Publications and source records attributed to J C Maroon.

At least 19 recordsLinked to original sources
PubMed1992

Percutaneous laser discectomy with the Ho:YAG laser.

A prototype Ho:YAG (2.15 microns) laser operating at 2-J/pulse, 3 Hz through a 600-microns fiber was employed to perform laser discectomies at the L3-4 disc through an 18G needle in five juvenile pigs. No temperature elevations were recorded in the posterior longitudinal ligament at the disc level and all animals recovered fully with no adverse sequelae, even immediately upon awakening from anesthesia. Pathologic examination demonstrated a wide swath of coagulation necrosis confined to the disc space. The Ho:YAG laser, owing to its close approximation to the intense 2.0 microns absorption band of water, appears to be a viable candidate for clinical trials of laser discectomy.

Adult↗
PubMed1992

Intracranial cryosurgery in a canine model: a pilot study.

Although virtually abandoned decades ago following the introduction of levodopa for the treatment of movement disorders, intracranial cryosurgery potentially offers a simple and accurate means of destroying deep-seated lesions when coupled with computed tomographic-stereotaxic placement techniques. We performed a pilot investigation of the size and histology of brain cryolesions in six dogs, using a 3-mm probe maintained at -160 degrees C for 6 minutes while simiultaneously monitoring the process by real-time ultrasound. Lesion diameter was 1.4 +/- 0.1 cm at less than or equal to 2 days but enlarged to 2.25 +/- 0.21 cm at 1 week, primarily at the expense of white matter. Ultrasound appearance of the lesion was characterized by a hyperechoic ice ball, the size of which consistently underestimated true size (determined by histology). By microscopy, the lesion was a hemorrhagic infarction that incited little surrounding edema and exhibited a sharp transitional zone. These data indicate that the cryosurgical probe can lesion significant volumes of brain in a reproducible and discrete fashion with minimal reaction to the surrounding tissue. Further work is required to clarify the observed "growth" of lesion size between days 2 and 7.

Animals↗
PubMed1992

Cryosurgery re-visited for the removal and destruction of brain, spinal and orbital tumours.

Advances in neuroimaging and cryosurgical techniques have prompted us to re-evaluate the potential of cryosurgical techniques for the removal and the destruction of various neoplasms. We have used cryosurgical instrumentation to remove tumours in the brain, spine and orbit in 71 patients without complications. Cryosurgery was used to facilitate removal and extraction in 64 and to destroy residual neoplasms when removal was incomplete in 7. Intraoperative real time ultrasonic imaging permitted precise delimitation of tumours from surrounding tissues and allowed monitoring during the production of cryosurgical lesions thus permitting heretofore unavailable visualization of the production of cryogenic lesions in the central nervous system. New cryosurgical instrumentation was used to produce lesions up to three times larger than similar sized probes previously available. Our results reconfirm that cryosurgery facilitates the removal of tumours in the brain, spinal cord and orbit, reduces blood loss in vascular tumours, and is effective in ablating residual neoplasms involving the superior sagittal sinus, torcula and parasagittal areas. A Doppler flowmeter proved useful for monitoring sagittal sinus blood flow during the production of cryosurgical ablation of residual tumour attached to the walls of the sagittal sinus. Recent advances in ultrasonic and neuroimaging coupled with stereotactic techniques and improvements in cryosurgical instrumentation may prove useful in the future percutaneous destruction of selective intracranial neoplasms.

Adult↗
PubMed1992

Cauda equina syndrome secondary to an improperly placed nucleotome probe.

Automated percutaneous lumbar discectomy has been shown to be a low morbidity procedure in the treatment of contained herniated lumbar discs. Described in this paper is a complication, i.e., a cauda equina syndrome secondary to a Nucleotome probe improperly placed in the thecal sac. The authors reemphasize the landmarks for the thecal sac, i.e., the medial border of the pedicles, and discuss the preventable nature of this type of complication.

Adult↗
PubMed1992

Comparison of the effects of total blood substitution during two different levels of hypothermic cardiac arrest.

The effect of total blood replacement with a solution containing neither hemoglobin nor fluorocarbon was studied under two different levels of hypothermia. Ten dogs were anesthetized and esophageal temperature lowered to about 24 degrees at which time exsanguination began. Upon cardiac arrest and the completion of exsanguination, continuous whole body closed chest extracorporeal circulation of an oxygenated blood substitute was begun. Hematocrit was 1% while core temperature remained less than 10 degrees C for 3 hours of perfusion during which nadirs of 1.3 degrees C (Group I, N = 5) and 7.3 degrees (Group II, N = 5) were achieved. Replacement of the perfusate with whole blood began once the dog was rewarmed to approximately 10 degrees C. All dogs survived the procedure. Two dogs from each group died by the fourth post-operative day but the others survived long term. Group II showed a faster return to normal based on motor behavioral, biochemical and hematological changes. Thus the combination of profound hypothermia and complete blood substitution with a solution lacking any special oxygen carrying molecule, can be tolerated for 3 hours using both levels of hypothermia, however, the warmer one appears to be associated with faster recovery.

Animals↗
PubMed1992

Complete blood substitution during profound hypothermic cardiac arrest in dogs.

This study compared the effects of 3 hours of cardiac arrest performed at 2 different levels of profound hypothermia in totally exsanguinated, blood substituted dogs. Dogs (N = 10) were anesthetized and esophageal temperature was lowered to 24 degrees at which time exsanguination began. Once exsanguination was complete and the heart had arrested, continuous whole body perfusion of an oxygenated blood substitute solution was performed for 3 hours. Core temperature during this period remained below 10 degrees C and reached nadirs of 1.3 degrees C in Group 1 (N = 5) versus 7.3 degrees C in Group II (N = 5). Once the dog was allowed to rewarm to 10 degrees C replacement of the perfusate with blood was begun. All dogs survived the procedure but 2 dogs from each group died by 4 days following the experiment. The remaining 6 dogs were observed for between 10 and 85 days. The group perfused with blood substitute at the warmer nadir had a faster recovery of motor behavior and showed smaller changes from normal in several biochemical and hematological parameters. These findings indicate that profound hypothermia and total blood substitution can be successfully achieved at either temperature nadir, but the warmer level appears to be associated with a faster recovery.

Animals↗
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

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↗