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Biomedical subjects

K Muraszko

Publications and source records attributed to K Muraszko.

16 recordsLinked to original sources
PubMed2002

Complete osseous regeneration of a large skull defect in a patient with cutis aplasia: a conservative approach.

Cutis aplasia (or aplasia cutis congenita) is a congenital absence of all skin layers, often extending through bone. This defect usually occurs in the scalp and can be extensive, exposing the dura mater, and deeper meninges. Treatment regimens for cutis aplasia have included early operative intervention, including skin and bone grafts, local scalp flaps, or free flaps to close the defect. In addition to the significant perioperative risks, these invasive procedures may inhibit the osteogenic potential of the dura to initiate and sustain bony closure of the defect. We report a case of an infant with Adams-Oliver syndrome and cutis aplasia involving a large portion of the skull that was treated conservatively with topical Silvadene dressings. No surgical treatment of bone or soft tissue reconstruction was necessary. This case report is the first to our knowledge to document complete bony restoration of the cranial vault through serial three-dimensional CT scans. The intensive therapeutic intervention in this case report allowed early discharge from the hospital, a gradual amelioration of the patient's alopecia as the hair-bearing scalp slowly covered the defect, and precluded the need for any subsequent bony reconstruction of the cranial vault. We hypothesize that conservative treatment of cutis aplasia maintains dural induction of osseous regeneration, and any treatment plan for bony defects of cutis aplasia should consider maintenance of dural integrity. Although further investigation is warranted, an initial trial of antimicrobial dressing care might optimally promote secondary closure of the cranial vault without the need for surgical intervention.

Administration, Cutaneous↗
PubMed2000

Intramedullary spinal tumors of disordered embryogenesis.

Abnormal spinal embryogenesis is quite commonplace. While greater than 90 percent of these errors of embryogenesis leads to occult spinal dysraphism with minimal neurologic or orthopedic sequelae, there is a significant minority of these anomalies which leads to the formation of the so-called 'congenital tumors of disordered embryogenesis'. The purpose of this article is to discuss the embryology, presentation, diagnosis and management of the spinal dysraphic states with particular emphasis on those errors which lead to mass lesions in the spinal canal such as dermoids, epidermoids, lipoma/lipomyelomeningocoele and neurenteric cysts. We also include lesions such as dermal sinus tracts and thickened filum terminale in our discussion with particular emphasis on their relationship to the tethered cord syndrome. Proper surgical management of these various conditions necessitates a thorough understanding of their embryologic etiology and the anatomic/physiologic ramifications that such lesions have on the developing spinal cord.

Child↗
PubMed1999

Treatment of children with medulloblastomas with reduced-dose craniospinal radiation therapy and adjuvant chemotherapy: A Children's Cancer Group Study.

PURPOSE: Medulloblastoma is the most common malignant brain tumor of childhood. After treatment with surgery and radiation therapy, approximately 60% of children with medulloblastoma are alive and free of progressive disease 5 years after diagnosis, but many have significant neurocognitive sequelae. This study was undertaken to determine the feasibility and efficacy of treating children with nondisseminated medulloblastoma with reduced-dose craniospinal radiotherapy plus adjuvant chemotherapy. PATIENTS AND METHODS: Over a 3-year period, 65 children between 3 and 10 years of age with nondisseminated medulloblastoma were treated with postoperative, reduced-dose craniospinal radiation therapy (23.4 Gy) and 55.8 Gy of local radiation therapy. Adjuvant vincristine chemotherapy was administered during radiotherapy, and lomustine, vincristine, and cisplatin chemotherapy was administered during and after radiation. RESULTS: Progression-free survival was 86% +/- 4% at 3 years and 79% +/- 7% at 5 years. Sites of relapse for the 14 patients who developed progressive disease included the local tumor site alone in two patients, local tumor site and disseminated disease in nine, and nonprimary sites in three. Brainstem involvement did not adversely affect outcome. Therapy was relatively well tolerated; however, the dose of cisplatin had to be modified in more than 50% of patients before the completion of treatment. One child died of pneumonitis and sepsis during treatment. CONCLUSION: These overall survival rates compare favorably to those obtained in studies using full-dose radiation therapy alone or radiation therapy plus chemotherapy. The results suggest that reduced-dose craniospinal radiation therapy and adjuvant chemotherapy during and after radiation is a feasible approach for children with nondisseminated medulloblastoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Pathophysiology of syringomyelia associated with Chiari I malformation of the cerebellar tonsils. Implications for diagnosis and treatment.

The mechanisms previously proposed for the progression of syringomyelia associated with Chiari I malformation of the cerebellar tonsils are controversial, leave many clinical observations unexplained, and underlie the prevalence of different operations currently used as initial treatment. To explore the mechanism of syringomyelia progression in this setting, the authors used anatomical and dynamic (phase-contrast and phase-contrast cine) magnetic resonance (MR) imaging, and intraoperative ultrasonography to examine the anatomy and dynamics of movement of the cerebellar tonsils, the wall of the spinal cord surrounding the syrinx, and the movement of cerebrospinal fluid (CSF) and syrinx fluid at rest, during the respiratory and cardiac cycles, and during Valsalva maneuver in seven affected patients. In all patients the cerebellar tonsils occluded the subarachnoid space at the level of the foramen magnum. Syringomyelia extended from the cervical to the lower thoracic segment of the spinal cord. No patient had evidence of a patent communication between the fourth ventricle and the syrinx on anatomical MR images, dynamic MR images, or intraoperative ultrasound studies. Dynamic MR images of three patients revealed abrupt downward movement of the spinal CSF and the syrinx fluid during systole and upward movement during diastole, but limited movement of CSF across the foramen magnum during the cardiac cycle. Intraoperative ultrasound studies demonstrated abrupt downward movement of the cerebellar tonsils during systole that was synchronous with sudden constriction of the spinal cord and syrinx. Decompression of the foramen magnum was achieved via suboccipital craniectomy, laminectomy of C-1 and C-2, and dural grafting, leaving the arachnoid intact. Immediately after surgery, the pulsatile downward thrust of the tonsils and constriction of the spinal cord and syrinx disappeared. Syringomyelia resolved within 1 to 6 months after surgery in all patients. Observations by the authors suggest the following previously unrecognized mechanism for progression of syringomyelia associated with occlusion of the subarachnoid space at the foramen magnum. The brain expands as it fills with blood during systole, imparting a systolic pressure wave to the intracranial CSF that is accommodated in normal subjects by sudden movement of CSF from the basal cisterns to the upper portion of the spinal canal. With obstruction to rapid movement of CSF at the foramen magnum, the cerebellar tonsils, which plug the subarachnoid space posteriorly, move downward with each systolic pulse, acting as a piston on the partially isolated spinal CSF and producing a systolic pressure wave in the spinal CSF that acts on the surface of the spinal cord.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1994

A special cyst puncture catheter for use in thick-walled or mobile intracranial cysts.

Having encountered a number of thick-walled or mobile symptomatic intracranial cysts that have resisted stereotactic puncture with standard blunt-ended ventricular catheters, the authors have designed a cyst puncture catheter that has a number of features helpful in overcoming this problem. The catheter and its use are described, and examples of difficult-to-puncture cysts are given.

Brain Diseases↗
PubMed1993

Pharmacokinetics and toxicology of immunotoxins administered into the subarachnoid space in nonhuman primates and rodents.

Immunotoxins have been suggested as possible therapeutic agents in patients with leptomeningeal carcinomatosis. The pharmacokinetics, stability, and toxicity of immunotoxins injected into the i.t. space were examined in rats and rhesus monkeys. Monoclonal antibodies specific for the human (454A12 and J1) and rat (OX26) transferrin receptors were coupled to recombinant ricin A chain. In monkeys, the maximally tolerated dose of the anti-human transferrin receptor immunotoxin (454A12-rRA) was a dose that yielded a nominal cerebrospinal fluid (CSF) concentration of approximately 1.2 x 10(-7) M. In rats, the 10% lethal dose (LD10) of the anti-human transferrin receptor immunotoxin was a dose yielding a nominal CSF concentration of 8.8 x 10(-7) M whereas the LD10 of the anti-rat transferrin receptor immunotoxin (OX26-rRA) was a dose yielding a nominal CSF concentration of 1.2 x 10(-7) M. Thus, the species-relevant antibody resulted in toxicity at a concentration one-seventh that of the immunotoxin with the irrelevant antibody. A comparison of the area under the concentration curve at the LD10 for rats with the area under the concentration curve at the maximally tolerated dose in monkeys and humans shows that the species-relevant immunotoxin was a better predictor of the toxic dose of the anti-transferrin receptor immunotoxin in humans than the irrelevant immunotoxin. The pharmacokinetics of the 454A12-rRA immunotoxin within the CSF of monkeys showed a biphasic clearance with an early-phase half-life of 1.4 h and a late phase half-life of 10.9 h. The clearance was 4.4 ml/h or approximately twice the estimated clearance due to bulk flow of CSF. Loss by degradation was ruled out because immunoblot analysis showed that the immunotoxin was stable for up to 24 h after administration. Possible losses in addition to sampling include diffusion into brain tissue and transcapillary permeation. The apparent volume of distribution was 10.1 ml or approximately three-fourths the total CSF volume of the monkey. Dose limiting toxicity corresponded with the selective elimination of Purkinje cells in both rats and monkeys and was manifested clinically as ataxia and lack of coordination. The onset of ataxia in monkeys occurred within 5 days and, in the more mild form, was reversible with time. There was evidence of only minimal inflammation within the CSF, and there were no signs of systemic toxicity. Immunotoxins injected into the subarachnoid space may have potential for treatment of leptomeningeal carcinomatosis.

Animals↗
PubMed1993

Surgical techniques of cranial vault expansion for increases in intracranial pressure in older children.

Standard craniofacial techniques to expand the cranial vault were successful in treating elevations of intracranial pressure (ICP) in 7 older children. Of the 7 patients, a diagnosis of craniosynostosis was made in 6 and deformational head deformity with slit ventricle syndrome in 1. There were 5 boys and 2 girls, whose ages ranged from 3 1/2 to 8 years (mean, 5.2 yr). Three patients had previously undergone surgical treatment of craniosynostosis. One patient presented with visual changes and papilledema. Another with a deformational skull deformity was shunt-dependent and was diagnosed with slit ventricle syndrome. This patient had undergone several temporal craniectomies to control recurrent symptoms of increased ICP. The remaining 2 patients appeared to have craniosynostosis as an explanation for reduced cranial vault size and elevated ICP, but the specific sites of sutural fusion could not be identified. Total follow-up ranged from 3 to 18 months, and evidence of resolution of signs and symptoms of increased ICP was achieved in each of the 7 patients. Plastic surgeons involved in caring for children with craniosynostosis should be particularly aware of the possibility of increased ICP developing or recurring following craniofacial surgery.

Cerebral Ventricles↗
PubMed1992

Retroperitoneal neurogenous choristoma.

A 6-year-old girl with urinary complaints underwent ultrasonography, which revealed a retroperitoneal cystic mass adjacent to the left kidney. Computerized tomography did not demonstrate whether the mass was an adrenal cyst or a duplicated upper pole segment. Exploration revealed a neurogenous choristoma, which is a collection of histologically normal tissue that is ectopically situated. We believe that this is the first report of this rare entity occurring in the retroperitoneum.

Child↗
PubMed1990

A study of the reactivity of feeding vessels to arteriovenous malformations: correlation with clinical outcome.

Isolated segments from the feeding arteries to arteriovenous malformations (AVMs) from 24 patients were studied in vitro. In a perfusion chamber, isometric contraction of these arterial rings to various vasoactive substances was recorded and correlated with the following: spontaneous activity, spasm as seen in the operating room; radiographic evidence of ectasia preoperatively and postoperatively; and postoperative course. Of the 24 patients studied, four patients had nonreactive AVM nutrient vessels upon in vitro testing. In addition, these vessel segments displayed no spontaneous activity although all of the other vessels tested developed spontaneous activity while in the perfusion chamber. The patients with "unreactive vessels" had an increased incidence of postoperative edema and hemorrhage in the surrounding brain, consistent with the symptoms of normal perfusion pressure breakthrough. Thus, our study utilizes an in vitro technique to evaluate a specific segment of the AVM complex, the feeding vessel, which permitted us to assess abnormalities of reactivity in these vessel segments. This method may be useful for future evaluations of the pathophysiology of AVMs.

Animals↗
PubMed1986

Management of pituitary tumors.

Pituitary adenomas represent the only true adenomas of the cranial cavity. In 1000 asymptomatic pituitary glands examined at autopsy, there was a 22.4 per cent incidence of undetected microadenomas. Advances in diagnostic endocrinology, in radiologic imaging, and in surgical and medical treatments have brought many more patients to the attention of the authors. Over the last 10 years, their treatment approaches have evolved to those presented in this article.

Acromegaly↗
PubMedDate not supplied

A comparison of continuous epidural infusion and intermittent intravenous bolus doses of morphine in children undergoing selective dorsal rhizotomy.

BACKGROUND AND OBJECTIVES: Selective dorsal rhizotomy (SDR) is associated with moderale to severe postoperative pain. Although the efficacy of epidural analgesia in this population has been demonstrated, it has not been compared with conventional intravenous (i.v.) analgesia. This prospective study compared the effects of epidural and i.v. morphine regarding postoperative analgesia, side effects, and outcomes in children following SDR. METHODS: Twenty-seven children were randomized to receive either epidural or i.v. analgesia. Children in the epidural group had a catheter placed by the neurosurgeon and received preservative-free morphine (Duramorph) 30 microg/kg, followed by an infusion of 3 microg/kg/h for 3 days. Children in the i.v. group received morphine 0.05-0.1 mg/kg intraoperatively, followed by 0.02 mg/kg doses postoperatively administered by nurses via a patient-controlled analgesia device. RESULTS: The epidural group experienced lower pain scores (P = .04) and fewer muscle spasms (P < or = .04), and tolerated activity better (P < or = .02) during the early postoperative period than the i.v. group. Side effects were similar between groups, with no respiratory depression in either group. Parents of children in both groups perceived an adequate level of comfort and were very satisfied with the analgesic technique. Additionally, parents believed that their child's postoperative pain was less than anticipated (P < or = .01). CONCLUSIONS: Both techniques provided effective postoperative analgesia with a similar incidence of side effects; however, our findings suggest that continuous infusions of epidural morphine improved overall comfort with lower pain scores, fewer muscle spasms, and improved tolerance of activity during the initial postoperative period.

Analgesia, Epidural↗