Search PubMed⌕ Search

Biomedical subjects

J C Maroon

Publications and source records attributed to J C Maroon.

At least 19 recordsLinked to original sources
PubMed1997

Defining the limits of survivorship after very severe head injury.

BACKGROUND: Reliable prediction of outcome after head injury is a daunting task. Although previous reports have highlighted the difficulties of determining outcome in the cohort of severe head injury Glasgow Coma Scale (GCS) score < or = 8), we wondered within the very severely injured population (GCS score 3-5) if a simple combination of clinical parameters may be predictive of poor outcome. METHODS: All patients admitted to a Level 1 trauma center with a GCS score of 3 to 5 from 1986 to 1991 inclusive (380 patients) were retrospectively reviewed and outcome a minimum of 6 months after injury was determined by chart review or telephone. RESULTS: Follow-up was accomplished in all but five patients (1.3%). Functional survival (nonvegetative) was correlated to admission GCS score, pupillary abnormalities, and age. As anticipated, overall functional survival was poor (12.5%), and even worse among those evidencing pupillary abnormalities (6.6%). Interestingly, there was an absence of survivors in the advanced age decades, with the oldest functional survivor of any GCS increasing in a stepwise fashion with increasing coma score. This translated into the oldest survivor of a GCS score of 3 being in their chronologic 30s, a score of 4 in their 40s, and a score of 5 in their 50s. Among patients older than these age decades, that is beyond this simple age/GCS cut-off (32.8% of cohort), there were no functional survivors (95% confidence interval 0, 2.4). CONCLUSIONS: Within the population of very severely head injured patients (GCS score 3-5), the simple combination of age and admission GCS score appears to predict accurately non-functional outcome in almost one third of patients. If confirmed at other centers, this may have wide-ranging implications regarding counseling of families, utilization of resources, and the design of head injury studies.

Adolescent↗
PubMed1996

Athletes with cervical spine injury.

Athletic injuries to the cervical spine are infrequent, but can present difficulty in both diagnosis and management. We designed a simple classification system consisting of three broad types of injuries to facilitate management decisions. Also included is a discussion of variations among injuries within each type and recommendations regarding the athlete's return to competition.

Athletic Injuries↗
PubMed1996

The role of postoperative irradiation in the management of sphenoid wing meningiomas. A preliminary report.

PURPOSE: To determine whether postoperative radiation therapy decreases recurrence rates in subtotally excised and recurrent sphenoid wing meningiomas. METHODS: Patients with primary subtotally excised and recurrent sphenoid wing meningiomas who underwent surgery between 1981 and 1994 (n = 105) were prospectively followed for recurrence. Postoperative radiation was not recommended in patients who had complete excision; therefore, their recurrence rates were not evaluated in this study. Patients with malignant meningiomas also were excluded from analysis. Recurrence was defined as evidence of tumor growth on neuroimaging with or without clinical symptoms. RESULTS: Follow-up information was available for 86 patients; 69 had primary subtotally excised tumors and 17 had recurrent tumors. Follow-up information was unavailable in the remaining 19 patients. Tumor location and histopathology, type of surgery performed, and patient sex and age were similar in the irradiated and nonirradiated subgroups. Postoperative irradiation was delivered to 31 patients with primary tumors and 11 with recurrent tumors; none of these 42 patients had recurrence during a mean observation period of 4.2 and 3.5 years, respectively. The nonirradiated group consisted of 38 patients with primary tumors and 6 with recurrent tumors; 16 of 18 patients who had primary meningiomas had a recurrence and 5 of 6 who had recurrent tumors had another relapse (mean interval between resection and recurrence, 4.4 years and 14 months, respectively). CONCLUSIONS: Postoperative radiation appeared to delay recurrence in subtotally excised and recurrent sphenoid wing meningiomas during the time frame of this study.

Adolescent↗
PubMed1996

The learning curve for acoustic tumor surgery.

Although operative experience is considered to be critically important in the surgical management of acoustic tumors, little objective evidence substantiates this claim. The present study was undertaken to determine whether a learning curve exists for acoustic tumor surgery. The first 96 acoustic tumor patients managed surgically by a new neurotologic team were retrospectively reviewed. A significant improvement (P<.0003; F=6.32) in the ability to achieve good (grade II or better) postoperative facial nerve function was identified. Improving trends for complete resection rate and hearing preservation were documented, and the incidence of cerebrospinal fluid (CSF) leaks declined; however, statistical significance was not achieved. For postoperative facial nerve function, approximately 60 cases were necessary before the new team achieved results similar to those of highly experienced surgeons. The frequencies of complete resection, CSF leaks, hearing preservation, stroke, and mortality were comparable to those of experienced neurotologic teams. The findings of this study may have implications for both patient care and physician training.

Clinical Competence↗
PubMed1996

Automated percutaneous discectomy.

Automated percutaneous discectomy is the most popular technique for intradiscal therapy of lumbar disc disease, with over 80,000 procedures performed worldwide to date. Success rates range from 55% to 85%, and complications are very infrequent (less than one percent). Very careful patient selection seems critical for success.

Automation↗
PubMed1995

A new solution for life without blood. Asanguineous low-flow perfusion of a whole-body perfusate during 3 hours of cardiac arrest and profound hypothermia.

BACKGROUND: The benefits of hypothermia for preventing ischemic injury are well known, but its application in surgery to protect the whole body during procedures requiring circulatory arrest is currently limited to < 1 hour at 15 degrees C using 50% hemodilution. In a significant departure from previous methods, we have developed a technique of asanguineous blood substitution with low-flow perfusion and cardiac arrest at < 10 degrees C in a canine model. Our approach has been to design a hypothermic blood substitute that would protect the brain and visceral organs during several hours of bloodless perfusion. Two different solutions have been designed to fulfill separate requirements in the procedure. METHODS AND RESULTS: With the use of extracorporeal cardiac bypass, 14 adult dogs were exsanguinated during cooling; 11 dogs were blood substituted using in combination the "purge" and "maintenance" solutions (group 1), and 3 dogs were perfused throughout with the "purge" solution alone as controls (group 2). After cardiac arrest, the solutions were continuously circulated for 3 1/2 hours by the extracorporeal pump (flow rate, 40 to 85 mL.kg-1.min-1; mean arterial blood pressure, 25 to 40 mm Hg). The temperature was maintained at < 10 degrees C (nadir, 6.6 +/- 0.1 degrees C) for 3 hours, and the hematocrit was kept at < 1% before controlled rewarming and autotransfusion. In the experimental group, the heart always started spontaneously in the temperature range of 11 degrees C to 27 degrees C, and 8 animals have survived long-term (current range, 14 to 110 weeks) without any detectable neurological deficit. In contrast, two control animals survived after extensive and aggressive cardiac resuscitation efforts; after surgery they exhibited transient motor and sensory deficits for approximately 1 week. Evaluation of biochemical and hematological parameters showed only a transient and inconsequential elevation in enzymes (eg, brain, liver, cardiac) in group 1 compared with the markedly greater elevations in group 2. For example, immediate postoperative values (mean +/- SEM) for lactate dehydrogenase were 114 +/- 10 for group 1 versus 490 +/- 210 for group 2 (P < .03); for SGOT, values were 93 +/- 18 for group 1 versus 734 +/- 540 for group 2 (P < .05). On day 1 for creatine kinase (CK), the group 1 value was 7841 +/- 2307 versus 71,550 +/- 2658 for group 2 (P = .03), and for CK-BB, the group 1 value was 108 +/- 22 versus 617 +/- 154 for group 2 (P = .03). Neurological evaluation using deficit scores (NDS) was based on a modification of the Glasgow Coma Scale score: 0, normal; 1, minimal abnormality; 2, weakness; 3, paralysis; 4, coma; and 5, death. At days 1 and 2 after surgery, NDS (mean +/- SEM) were 0 +/- 0 for the experimental group versus 1.5 +/- 0.5 for the control group. At days 3 and 7 after surgery, NDS were 0 +/- 0 for group 1 versus 1.0 +/- 1.0 for group 2. CONCLUSIONS: The faster neurological recovery of dogs treated with the "intracellular-type" maintenance solution supports the biochemical data showing the benefits of this type of blood substitute for extending the safe limits of hypothermic cardiac arrest procedures to > 3 hours.

Animals↗
PubMed1995

Cryoprobe-assisted removal of spinal cord tumors: technical note.

The application of a cryosurgical contact probe to assist in the removal of intraspinal neoplasms is described. Most often used by ophthalmic surgeons for intraocular extraction purposes, these .89-3 mm cryoprobes provide an ideal safe "handle" when attached to intramedullary or extramedullary spinal cord tumors and facilitate dissection and removal with standard microsurgical techniques.

Cryosurgery↗
PubMed1995

Value of surgical intervention in the treatment of glioma.

The benefit of cytoreductive surgery in the management of glioma remains speculative. We therefore reviewed all confirmed deaths in our Neuro-Oncology Program and examined various clinical factors related to survival. There were 63 patients (34 males/29 females), with an average age of 57.6 years. The pathology was glioblastoma in 44 and anaplastic astrocytoma in 19; median survival was 12 months. Forty patients underwent at least one craniotomy, following which 22.5% achieved a gross total resection, 23 had biopsy only. Only age and gross total resection of tumor as judged by postoperative MR (CT in 2 cases) correlated significantly with outcome. The subtotal craniotomy group and biopsy only cohort were indistinguishable (median survival 11 vs. 10 months, respectively). Although craniotomy associated with gross total resection results in enhanced survival (median 27 months), subtotal tumor excision offers little beyond a diagnosis. Therefore, careful and realistic preoperative assessment of glioma patients ought to be performed to determine optimal surgical management.

Biopsy↗
PubMed1994

Laser discectomy. Comparison of systems.

Percutaneous methods of lumbar disc removal have gained wide popularity since the introduction of the automated suction device. Newer methods to enter this field include the Nd:YAG and Ho:YAG lasers. To date, no experimental model exists to compare the efficacy of disc removal of these devices. An in vitro disc elastance (pressure/volume) model was designed that accurately reflects the mass of dry disc removed after any type of discectomy procedure. The experimental design consists of an infusion pump compressing a static column of air in line with the disc through a 12-gauge needle. Both mechanical and laser devices exhibited a reproducible treatment plateau, beyond which no disc removal was effected. Total energy, as opposed to power, was found to be the main determinant of the extent of disc removal during laser discectomy. Finally, in the experimental model of juvenile swine the automated suction device exhibited superior disc removal compared to the two lasers, but the clinical applicability of this is debatable. Disc space elastance offers a rapid and reproducible method to quantitate the extent of disc removal after intradiscal treatment methods and if employed in human cadaver spines may minimize the need for clinical trials to compare different devices and techniques.

Animals↗
PubMed1994

Laser discectomy: a review.

The percutaneous treatment of lumbar disc disease with laser energy has emerged recently as an alternative to open surgical or even mechanical percutaneous methods. Although numerous laser wavelengths have been employed in both the experimental and clinical settings, no consensus exists regarding selection of laser, treatment duration, or energy requirements. Inspection of the disc/water absorption spectrum combined with the limitations of the fiberoptic delivery systems argue for the use of lasers near 2.0 microns, such as the 2.1-microns Ho:YAG. Although recently developed in vitro models have allowed for laser system comparisons, most clinical work has been empiric, uncontrolled, and in very small series.

Animals↗
PubMed1994

Recurrent spheno-orbital meningioma.

A series of 15 patients who underwent neurosurgical procedures for recurrent spheno-orbital meningioma is reported. There were 11 women and four men, with a mean age of 46 years. The mean duration between the first and second operations was 46 months. Progressive proptosis without neurological deficit was the most common symptom. All tumors were large at the time of reoperation and involved the greater and lesser wings of the sphenoid bone and the orbit. Aggressive resection in all patients resulted in no deaths and only slight morbidity, with the exception of one patient who developed blindness 24 hours after surgery due to central retinal artery occlusion. Fourteen patients were improved cosmetically and one patient, treated early in the series, had persistent proptosis due to inadequate bone removal. No attempt was made to remove tumor within the cavernous sinus in patients who were neurologically normal. Although postoperative imaging demonstrated complete gross excision of tumor in nine patients, 10 underwent conventional radiation therapy for residual tumor visualized at the time of surgery in the dura of the superior orbital fissure, the cavernous sinus, or the basal optic canal. Although this study is inconclusive and requires further long-term documentation, no recurrences have been seen to date in the follow-up period, ranging from 16 to 95 months. The following important points are discussed: 1) the failure by experienced surgeons to radically excise bone, tumor, and involved dura at the first operation; 2) the importance of early aggressive therapy, depending upon the patient's age and medical condition; 3) the almost invariable intracranial dural involvement, which at times was seen only by gadolinium-enhanced magnetic resonance imaging and not visualized on computerized tomography; 4) an illustrated stepwise surgical technique for complete resection through a small craniotomy without the need for complicated reconstruction of the orbit or temporal fossa; 5) the role of radiation therapy when removal is incomplete or deemed hazardous because of cavernous sinus involvement; and 6) the excellent cosmetic results possible with minimal morbidity and no mortality.

Adult↗
PubMed1993

Percutaneous discectomy for lumbar disc herniation.

Percutaneous discectomy for lumbar disc herniation is a well established, low-risk procedure effective in 70% to 80% of appropriately selected patients. Advantages include the use of local anesthesia, minimal tissue disruption, no epidural fibrosis or scarring, and negligible biomechanical effect. The risk of automated percutaneous lumbar discectomy is significantly less than that of traditional surgery.

Adult↗
PubMed1993

Temperature distributions in porcine orbital tissues following the use of CO2 and Nd:YAG lasers.

Temperature distributions in the orbital tissues of a live porcine model were obtained during and immediately following the application of CO2 and Nd:YAG (both contact and noncontact) laser irradiation to muscle tissue adjacent to the optic nerve. Temperatures were measured with thermocouples and an infrared-sensitive thermographic camera system. Significant thermal spread was observed only in the case of the contact Nd:YAG laser, along with histologic evidence of damage to the optic nerve. After the laser was switched off, the target cooled with a time constant on the order of 10 seconds.

Adipose Tissue↗
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↗