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Biomedical subjects

L Kesterson

Publications and source records attributed to L Kesterson.

At least 19 recordsLinked to original sources
PubMed1997

Treatment of pneumonia in mechanically ventilated trauma patients. Results of a prospective trial.

OBJECTIVES: To determine the efficacy and magnitude of associated adverse effects of 2 different antibiotic regimens for the treatment of pneumonia in intubated surgical patients and to assay and compare blood samples and bronchoalveolar lavage fluid with respect to some host-defense parameters, especially in patients with unilateral pneumonia. DESIGN: Randomized, prospective, unblinded clinical comparison of 2 treatment arms with respect to intent to treat and clinical and microbiologically evaluable patients. SETTING: Six university surgical services in teaching hospitals with modern and well-staffed intensive care units. INTERVENTIONS: The consistency and objectively of the diagnosis of pneumonia was improved by the use of a grid of diagnostic parameters. Aggressive mechanical approaches to pneumonia in intubated surgical patients were supplemented by therapeutic use of aztreonam and vancomycin hydrochloride or combined imipenem and cilastatin sodium. RESULTS: Patients randomized to the aztreonam-vancomycin group were somewhat more ill, fared slightly better, and had fewer serious drug-related side effects than did those treated with imipenem-cilastatin (all P > .05). Immunologic parameters assessed by evaluation of bronchoalveolar lavage fluid showed differences between infected pulmonary lobes and noninfected ones; some changes were also noted in patients who recovered compared with those whose pneumonia persisted or recurred. CONCLUSIONS: Clinical studies of pneumonia in surgical patients need to be stratified to assure comparability, to identify patients in whom treatment is likely to fail, and to display differences between more and less effective therapies. Studies of blood and bronchoalveolar lavage samples showed that certain local and systemic immunologic parameters correlate with clinical status and outcome.

Aztreonam↗
PubMed1994

Preoperative spinal angiography for lateral extracavitary approach to thoracic and lumbar spine.

PURPOSE: To establish the safety, efficacy, and value of preoperative angiography in the surgical management of thoracic and lumbar spine disease, in which it is important to avoid injury to the artery of Adamkiewicz or other vessels that supply the spinal cord. METHODS: Sixty-one patients were evaluated primarily using digital subtraction angiography, low-osmolar or nonionic contrast agents, selective catheterization limited to the region of disease, and careful angiographic techniques. RESULTS: Two minor (small hematomas of the groin) and no major complications of angiography were encountered. Arterial supply to the spinal cord was identified in 22 patients. In 17 patients (77%), the arterial supply was in the region of planned surgery. In each of these patients the surgical approach was altered, either by dictating the use of a posterior surgical approach (four patients) or by altering the side of the lateral extracavitary approach (13 patients). CONCLUSION: Spinal angiography is a safe preoperative examination for thoracic and lumbar spine surgery. It is specifically useful when the lateral extracavitary surgical approach to spinal cord decompression and fusion (which predictably interrupts the terminal end-arterial blood supply to the spinal cord, if present) is planned.

Adolescent↗
PubMed1993

Clinical behavior of acoustic tumors. A flow cytometric analysis.

OBJECTIVE: Recently, nonsurgical treatment of acoustic tumors has been advocated as an alternative to surgical resection. Because of the relatively short follow-up in reported series of radiation-treated acoustic tumors, the lack of growth of some tumors may merely reflect the variable biologic growth potential of these tumors and not the result of treatment. DNA flow cytometry has been used to predict biologic activity in other solid tumors. It is applied in this study to assess the variability of growth potential in a typical acoustic tumor population and to determine whether relationships exist between flow cytometric data and clinical characteristics of acoustic tumors. DESIGN: DNA flow cytometry techniques were used to evaluate formalin-fixed, paraffin-embedded tissue previously obtained from patients who were surgically treated for acoustic neuromas. Relationships between flow cytometry data and historical data were also statistically evaluated. SETTING: Tissue samples were from patients of a large private otologic practice. PATIENTS: Subjects were a convenience sample of 49 patients (26 female and 23 male) with a mean age of 59 years who had undergone surgical removal of an acoustic neuroma. None of the patients had other stigmata of neurofibromatosis or tumor recurrence. All tissue specimens were pathologically confirmed acoustic neurons, with a range in tumor size from 1 to 6 cm. MAIN OUTCOME MEASURES: The measures included DNA ploidy and S-phase fraction. Historical data included age, sex, size of tumor, presenting symptom, and symptom duration. RESULTS: All 49 tumors showed a diploid distribution, with S-phase values ranging from 1.07% to 20.74% (mean +/- SD, 6.30 +/- 4.24). The ploidy and S-phase data compare favorably with previously published data in which fresh tissue was used. There were no statistically significant relationships between S-phase value and historical data. CONCLUSIONS: The wide range of S-phase values is consistent with a large variation in tumor growth potential and suggests caution in interpreting the results of radiation treatment of acoustic tumors when follow-up relatively short.

Adult↗
PubMed1992

Slit ventricle syndrome in children: clinical presentation and treatment.

Symptomatic ventricular coaptation, or the slit ventricle syndrome, is frequently described and recognized as a clinical entity in the pediatric population. It is characterized by symptoms of shunt failure (i.e., ataxia, obtundation, nausea, vomiting, lethargy, irritability, and complaints of headache) and the CT findings of ventricular coaptation (slit-like ventricles). This study of twenty-two children with this syndrome reflects the variety of possible clinical presentations, and the variety of available treatment modalities. Multiple therapeutic approaches were required in seven of the patients. This illustrates not only an evolving treatment regimen, but also that a single treatment modality is not universally effective. Six patients needed only occasional symptomatic support. Blockage and/or removal of the shunt system was the definitive therapy in six patients, pressure augmentation in nine patients, and subtemporal craniectomy in one. This article outlines the theoretical pathophysiology, and a scheme for the management of patients with this syndrome.

Cerebral Hemorrhage↗
PubMed1992

Histological comparison of autogenous canine fascia lata, Gore-Tex, lyophilized human fascia lata, and autogenous canine vein for vascular patch graft material in a canine arteriotomy model.

Autogenous fascia lata has found little clinical use as a vascular patch graft material. Previous experience, however, suggests that it possesses attributes that might make it useful in this regard. To assess its efficacy as a vascular patch graft, nine adult mongrel dogs each underwent four arteriotomies with placements of patch grafts. The four sites included both carotid arteries and both femoral arteries. In each animal, one of four patch graft materials (autogenous canine fascia lata, Gore-Tex, lyophilized human fascia lata, and autogenous canine vein) were placed as patch material at the arteriotomy site utilizing 7-0 running sutures and loop magnification. The site for placement of each graft material was rotated serially in the animals so that each site would have equal numbers of all four graft materials applied. The animals were killed at either 6 to 8 weeks or 11 to 12 weeks after angiography of all four vessels. The specimens were then evaluated histologically. No difference was observed among any of the patch graft materials with regard to myofibroblast plaque formation. Inflammatory responses were noted to be substantially less in the canine fascia lata group than in the other three groups. Granuloma formation, however, appeared to be most significant in the autogenous canine vein group. Only one vessel was occluded. Aneurysm or pseudoaneurysm formation was not noted in any specimen. It appears from the above results that autogenous fascia lata may be an appropriate alternative to currently utilized arterial patch graft materials and that it should be evaluated further for this purpose.

Animals↗
PubMed1991

Cervical laminectomy and dentate ligament section for cervical spondylotic myelopathy.

Seventy-five patients who underwent surgical treatment for cervical spondylotic myelopathy were evaluated with respect to the operative procedure performed and their outcome. Forty patients underwent a laminectomy plus dentate ligament section (DLS), 18 underwent laminectomy alone, and 17 underwent an anterior cervical decompression and fusion (ACDF). The patients were evaluated postoperatively for both stability and for neurologic outcome using a modification of the Japanese Orthopaedic Association Assessment Scale. Functional improvement occurred in all but one patient in the laminectomy plus DLS group. The average improvement was 3.1 +/- 1.5 points in this group; whereas the average improvement in the laminectomy and the ACDF groups was 2.7 +/- 2.0 and 3.0 +/- 2.0 points respectively. All of the patients who improved substantially (greater than or equal to 6 points) in the laminectomy plus DLS and the laminectomy alone groups had normal cervical spine contours (lordosis). The remainder had either a normal lordosis or no curve (no kyphosis or lordosis). All patients in the ACDF group had either a straight spine or a cervical kyphosis. These factors implicate spine curvature, in addition to choice of operation, as factors which are important in outcome determination. No problems with instability occurred in either the laminectomy or the laminectomy plus DLS group. Two patients incurred problems with stability in the ACDF group. Both required reoperation. In addition, four patients in this group who initially improved, subsequently deteriorated. Six patients in the laminectomy plus DLS group had a several day febrile episode related to an aseptic meningitis process. Laminectomy plus DLS is a safe and efficacious alternative to laminectomy for the treatment of cervical spondylotic myelopathy. The data presented here suggests that myelopathic patients with a cervical kyphosis are best treated with an ACDF and that patients with a normal cervical lordosis are best treated with a posterior approach. Although some selected patients may benefit from DLS, no criteria are available which differentiate this small subset of patients.

Adult↗
PubMed1991

Civilian craniocerebral gunshot wounds.

Experience with 120 patients who incurred a gunshot wound to the head with dural penetration is presented. All of the patients were managed by a standard resuscitation protocol and assigned a clinical grade based on their level of consciousness both at the time of presentation and at 2 to 4 months after injury. Fifty patients (42%) underwent surgery. Twenty-eight patients (23%) had a good recovery, 19 (16%) were moderately disabled, 6 (5%) were severely disabled, and 67 (56%) died. All patients who were alert and awake with a normal or near normal neurological examination at the time of admission survived with a good outcome. All but 4 patients who were comatose at the time of admission died. Nine patients, however, who were not comatose at the time of admission died from potentially preventable causes. In 3 of these patients, a more aggressive diagnostic approach (including cerebral angiography) may have altered their ultimate outcome. An expeditious approach to the trauma victim with a comprehensive management scheme after injury may have altered the course in the remainder of these patients.

Adult↗
PubMed1991

A new method of methyl methacrylate fixation in skull reconstruction.

Fifty-two methyl methacrylate cranioplasties were performed in 47 patients over a 5-year period. The indications for the original craniectomy fell into four categories. Nine patients had a craniectomy for tumor, 32 for trauma, 5 for infection, and 1 for aneurysm. A new approach, which eliminates the need for suture or wire fixation and which facilitates intraoperative calvarial contouring, is presented. An excellent cosmetic result is the norm with this technique.

Adolescent↗
PubMed1991

Evaluation and treatment of atlas burst fractures (Jefferson fractures).

Although several large series of atlas fractures have been reported recently, none has concentrated on the evaluation and treatment of atlas burst fractures (Jefferson fractures). The treatment of this fracture is challenging. Its diagnosis may easily be missed due to concerns about associated trauma and absence of neurological signs. In addition, the open-mouth anteroposterior x-ray study, which is usually pathognomonic for the diagnosis, is often inadequate or not obtained. In order to clarify the diagnosis and treatment of this disorder, 17 cases of Jefferson fracture treated between 1982 and 1989 at the Louisiana State University Affiliated Hospitals are presented. The diagnosis was delayed in three patients because of a low index of suspicion and inadequate x-ray films. Four patients were noted to have unstable Jefferson fractures, all of these had an associated Type II odontoid fracture and were treated with occiput-C-2 wiring and fusion. The remainder of the patients had stable Jefferson fractures and were managed with Minerva jackets or rigid collar stabilization. No significant complications related to the treatment of the Jefferson fracture occurred in this series. One patient died from associated injuries; however, the remaining patients enjoyed an excellent long-term result with the acquisition of spinal stability and the resolution of subjective complaints.

Adolescent↗
PubMed1991

Texas Scottish Rite Hospital rod instrumentation for thoracic and lumbar spine trauma.

The authors present their experience with 28 patients who had incurred unstable thoracic or lumbar spine fractures and who were intraoperatively stabilized with the Texas Scottish Rite Hospital (TSRH) universal instrumentation system. These patients were treated over a 1-year period and reflect an evolving insight into the treatment of thoracic and lumbar spine trauma with universal instrumentation. The TSRH instrumentation system appears equivalent to the more established Cotrel-Dubousset system in most respects. The construct design of the TSRH system facilitates the safe application of a rigid spinal implant. No cases of instability or pseudoarthrosis were observed during an average follow-up period of 9 months, (minimum 3 months). As the surgical treatment plan evolved, shorter and more compact constructs were increasingly utilized. There were no cases of instrumentation failure, regardless of the number of spinal levels fused or the number of levels instrumented. The value of using short rods when possible is emphasized: they may decrease the incidence of delayed instability and discomfort related to loosening at the hook/bone interface compared to that observed when long-rod systems are used in association with short spine fusions causing a fusion/instrumentation mismatch.

Adolescent↗
PubMed1990

The diagnosis of infections associated with acrylic cranioplasties.

Fifty-two methylmethacrylate cranioplasties were performed on forty-seven patients over a five year period. Two cranioplasties became infected and required removal. The overall infection rate for methylmethacrylate cranioplasty was thus 2/52 or 3.8%. Both of these patients had bifrontal cranioplasties involving both orbital rims and the frontal sinus. The infection rate for those cranioplasties involving the frontal sinus was 2 of 9 or 22%. None of the 43 cranioplasties not involving the frontal sinus became infected. Ten patients in this series had postoperative CT scans. Gas within the non-infected methylmethacrylate could simulate infection, making it difficult to diagnose cranioplasty infections by CT. Although certain CT changes, such as epidural air and soft tissue swelling, may be observed only with infected cranioplasties, the clinical picture is the only truly reliable indicator of infection.

Abscess↗
PubMed1990

Effect of dosage and timing of administration of naloxone on outcome in the rat ventral compression model of spinal cord injury.

The effect of the dosage and timing of administration of naloxone after spinal cord injury in rats via the ventral compression technique is presented. The rat ventral compression technique allows for a ventral compression of the spinal cord without the requirement of a previous laminectomy. It therefore facilitates the creation of an experimental lesion that is similar to that observed in the human clinicopathological situation. The first part of the two-part study presented herein involved the determination of the optimal dose of naloxone, administered intraperitoneally 45 minutes after the creation of the lesion. Of the groups studied (control group through 10.0 mg/kg group), 2.0 mg/kg of naloxone proved to be superior to both lesser and greater dosages. The second part of the study involved the administration of a 2.0 mg/kg dose of naloxone at varying intervals ranging from 10 minutes before lesioning to 24 hours after lesioning. A multiphasic response was again demonstrated, with an optimal time of administration occurring 45 minutes after the creation of the lesion. A significant effect was offered by a midrange dose of naloxone (2.0 mg/kg), administered at 45 minutes after injury (P less than 0.02 by analysis of variance and Duncan's multiple range test). These findings are discussed with respect to recent evidence regarding the effects of narcotic antagonists on both mu and kappa narcotic receptors. Past and future experiments must account for these responses to multiphasic dosage and timing of administration. Failure to do so may lead to erroneous conclusions.

Animals↗
PubMed1990

Fascia lata graft as a dural substitute in neurosurgery.

We present 37 cases in which fascia lata was used for dural patching when there was inadequate regional tissue, such as pericranium or temporalis fascia to repair the dural defect. Operative indications included tumor in 17 patients (46%), trauma in nine (25%), cerebrospinal fluid fistula in seven (19%), infection in two (5%), dural patching in two (5%). Follow-up ranged from one month to five years, with an average follow-up of two years. There were no cranial or spinal complications related to the fascia lata grafting (including cerebrospinal fluid leakage, meningitis, and wound infection). Fascia lata is relatively simple to obtain, but harvesting necessitates a second incision; this second incision resulted in no complications in our patients.

Adult↗
PubMed1990

A new rat spinal cord injury model: a ventral compression technique.

A new rat spinal cord injury model, which uses a modification of a DeBakey aortic aneurysm clamp to create the injury, is presented. The model produces a ventral persisting mass (bone and soft tissue) without the requirement of a prior decompressive operation (laminectomy). Modifications of the original technique have resulted in a nil surgical mortality rate. This technique has been applied to 138 animals. It has produced a consistent percentage of animals with complete myelopathies, as well as incomplete myelopathies and animals without apparent injury. The percent of baseline neurological function lost (change in degrees of the angle of tilt as measured by the inclined plane technique) in each group of surviving animals was 58, 36, and 9%, respectively. Sagittal postmortem sections confirmed mass lesions located ventral to the spinal cord. Histological sections confirmed neuronal loss consistent with the neurological findings.

Animals↗
PubMed1990

Dose-dependent effects of naloxone and methylprednisolone in the ventral compression model of spinal cord injury.

A study of the dose-response effects of naloxone and methylprednisolone after rat ventral spinal cord injury is presented. The spinal cord injury model used herein is unique in that it results in a ventral compression of the spinal cord without the need for a prior laminectomy. This allows for a close approximation of the human clinicopathological situation. There was a statistically significant positive effect on neurological outcome with a naloxone dose of 2.5 mg/kg, whereas higher and lower doses yielded little or no influence on outcome. Methylprednisolone was observed to offer similar results. These results, however, did not achieve statistical significance. The early administration of moderately high doses (45-60 mg/kg), however, offered the best results. The responses to the treatment regimens presented here offer hope for spinal cord injury victims. The observed dose-response relationships indicate that erroneous conclusions may arise from studies using inappropriate doses of narcotic antagonists, as well as other drugs.

Animals↗
PubMed1989

Naloxone and mortality in the gerbil stroke model.

Endorphins and narcotics have been implicated in the exacerbation of neurologic deficits after stroke. To test the theory that narcotic antagonists might offer an improvement in neurologic sequelae following stroke, we administered various doses of naloxone intraperitoneally to 50 adult gerbils 45 minutes after carotid artery transsection. Low-dose naloxone therapy (1.0 to 2.5 mg/kg) was more effective in preventing death than either control (sterile saline) or high-dose naloxone (10 mg/kg). A naloxone dose of 1.0 or 2.5 mg/kg offered a significant improvement in mortality over both the control and the high-dose therapy (P = .026). It appears that an appropriate dose of naloxone (1.0 to 2.5 mg/kg), given early enough to alter outcome, offers an improved survival in the gerbil stroke model. This finding obviously has significant implications for the use of narcotic antagonists in human beings with stroke.

Animals↗