PubMed Health⌕ Search

Biomedical subjects

J B Delashaw

Publications and source records attributed to J B Delashaw.

At least 19 recordsLinked to original sources
PubMed1992

Modified supraorbital craniotomy: technical note.

The authors present a surgical approach that incorporates the frontal sinus and extends a supraorbital craniotomy to include the lateral orbital rim and zygoma. The craniotomy provides wide exposure of the anterior fossa, orbit, ipsilateral middle fossa, and cavernous sinus. The procedure can be performed easily, and the bone flaps can be secured rapidly back into the anatomical position at the time of closure. This modified supraorbital craniotomy is ideal for large benign lesions originating along the sphenoid wing or orbit that expand into the anterior fossa.

Craniotomy↗
PubMed1992

Anterior third ventricle meningioma in an adolescent: a case report.

A case of an anterior third ventricular meningioma in a 17-year-old girl is presented. Gross total resection of this tumor with minimal morbidity was accomplished by transcallosal exposure through a frontal craniotomy. A review of the literature implies that surgical morbidity and mortality for the removal of third ventricular meningiomas markedly improved with the use of the operating microscope. Despite advanced imaging capabilities, radiographic analysis of a solid third ventricular mass may not always determine tissue diagnosis. In addition, preoperative placement of a ventriculoperitoneal shunt will treat hydrocephalus, but may limit the surgical options for tumor exposure. The differential diagnosis for this solid anterior third ventricular mass is presented, and the method of treatment for this case is discussed.

Adolescent↗
PubMed1991

Heterogeneity in conducted arteriolar vasomotor response is agonist dependent.

Microiontophoresis of acetylcholine onto cheek pouch arterioles of the pentobarbital-anesthetized hamster results in both a local response at the pipette tip and a conducted dilator response. The conducted response is not dependent on blood flow, and its magnitude decays with distance from the site of stimulation. In an attempt to define the mechanism responsible for activation of arteriolar conduction, vasoactive agonists directed toward different vascular wall cell types, receptor types, and second messengers were applied to arterioles by pressure-pulse microejection. As expected, microapplication caused a consistent arteriolar response at the site of application with each of the agonists tested (local response). However, a high degree of variability was observed among agonists in their ability to produce conducted responses. Acetylcholine, muscarine, and phenylephrine, invariably induced both local and conducted responses. In contrast, bradykinin, substance P, papaverine, isoproterenol, and adenosine, though consistently inducing local responses, displayed a highly variable ability to induce the conducted responses. When conduction was observed, the arteriolar response was similar regardless of the agonist used to induce the response. Microejection of sodium nitroprusside or arginine vasopressin produced local arteriolar responses with no evidence of a conducted response regardless of the dose. These studies reveal previously undetected heterogeneity among microvessel responses and may reflect variations in the coupling mechanisms linking the local vasomotor response to the conducted response.

Acetylcholine↗
PubMed1991

Cranial deformation in craniosynostosis. A new explanation.

Skull growth after premature fusion of a single suture was described by Virchow in 1851. He observed that growth was restricted in a plane perpendicular to a fused suture. However, he failed to predict the compensatory growth patterns that produce many of the deformities recognized as features of individual craniosynostosis syndromes. The deformities resulting from premature closure of a coronal, sagittal, metopic, or lambdoid suture can be predicted by the following observations: (1) cranial vault bones that are prematurely fused act as a single bone plate with decreased growth potential; (2) asymmetrical bone deposition occurs mainly at perimeter sutures, with increased bone deposition directed away from the bone plate; (3) sutures adjacent to the stenotic suture compensate in growth more than those sutures not contiguous with the closed suture; and (4) enhanced bone deposition occurs along both sides of a nonperimeter suture that is a continuation of the prematurely closed suture. These four rules were derived by critically examining the clinical deformities observed with each form of craniosynostosis. These rules assume that cranial sutures have the capacity to compensate by depositing bone asymmetrically along their edges. Unequal growth patterns have been demonstrated in the frontonasal suture of rabbits by Selman and Sarnat. In addition, unequal bone deposition has also been demonstrated along the parieto-interparietal suture in albino rats by Baer. Human studies to determine if asymmetrical bone deposition actively occurs along cranial vault sutures in response to a stenotic suture have not been performed, however. It is also unclear whether these four guidelines apply to cranial base abnormalities observed with craniosynostosis. As new radiologic techniques develop to define the configuration of the skull in intricate detail, a skull pattern of growth explaining the pathogenesis of all deformities created by premature fusion of a cranial vault suture may become apparent.

Animals↗
PubMed1991

Surgical treatment of metopic synostosis.

Metopic synostosis can present with various skull abnormalities for which early surgical treatment can provide significant benefit to the patient. Correction of skull deformities associated with metopic synostosis requires accurate assessment of the full range of craniofacial defects within context of the patient's age. Alteration in the characteristics of cranial bone as the child grows older necessitates modifications in techniques used for bony remodeling. Changes in the rate of brain and cranial vault growth also must be considered for adjustments in fixation methods. Thus, both the patient's age and the severity of aesthetic deformity dictate the surgical techniques used in the correction of metopic synostosis.

Child, Preschool↗
PubMed1990

Treatment of right hemispheric cerebral infarction by hemicraniectomy.

An anecdotal series of nine patients (three men and six women with an average age of 57 years) presented with progressive neurologic deterioration while on medical therapy for large right hemispheric cerebral infarction. Clinical signs of uncal herniation (anisocoria or fixed and dilated pupils, and/or left hemiplegia with right decerebrate posturing) were present in seven of these nine patients. Computerized tomography of the head confirmed mass effect from cerebral edema. It was the clinical judgment of the treating neurologists and neurosurgeons that each of these nine patients would perish unless surgical decompression of the infarcted brain was performed. Accordingly, each was treated with right hemicraniectomy and dural augmentation. Six patients demonstrated neurologic improvement on the first postoperative day. One patient, with a postoperative diagnosis of lung cancer, died 1 month after surgery. The remaining eight patients are currently living with their families with a follow-up period ranging from 5 to 25 months. Patient outcome as evaluated by the Barthel Index indicates that three individuals are functioning with minimal assistance and that the remaining six patients are functionally dependent. After rehabilitative therapy, four patients returned for elective cranioplasty. These results suggest that hemicraniectomy can be an effective lifesaving procedure for malignant cerebral edema after large hemispheric infarction.

Activities of Daily Living↗
PubMed1990

Floating C-shaped orbital osteotomy for orbital rim advancement in craniosynostosis: preliminary report.

A method of lateral orbital rim advancement is described for periorbital deformities associated with coronal and metopic synostosis in infants. The technique offers the advantages of a smooth lateral rim contour and improvement in accompanying malar recession. In 13 patients with follow-up periods of up to 2 years following surgery, improved orbital contour has been appreciated. Further observation is warranted to determine whether this improvement will last into adulthood.

Child, Preschool↗
PubMed1990

Treatment of bilateral coronal synostosis in infancy: a holistic approach.

Bilateral coronal synostosis often results in a turribrachycephalic skull shape. Reduction of skull height and elongation of the anteroposterior axis of the skull while preserving normal cerebral function are the major therapeutic goals. A surgical technique is described which can successfully accomplish these goals in a single operative procedure.

Craniosynostoses↗
PubMed1990

Preoperative superselective arteriolar embolization: a new approach to enhance resectability of spinal tumors.

The extent of surgical resection of spinal tumors is frequently limited by blood loss and technical difficulty associated with the vascularity of the tumors. We report here the use of superselective percutaneous arterial embolization to reduce the rate of blood loss at the time of surgical resection and enhance resectability. The types of tumors treated were metastatic renal carcinoma, metastatic thyroid carcinoma, metastatic melanoma, and giant cell tumor of the sacrum. Two of the patients required repeated embolization and surgery for recurrent symptoms. The estimated blood loss in seven of nine procedures performed on the six patients ranged from 300 to 800 ml, after which no transfusion was required. In two procedures, extensive resection of very large tumors resulted in larger losses of blood, and postoperative transfusion was necessary. No significant complications of embolization or surgery occurred. A key factor in our embolization technique is the use of microfibrillar collagen, which allows occlusion of tumor vessels as small as 20 microns and may prevent reconstitution of the embolized vessels by collateral flow. We conclude that preoperative arterial embolization enhances the resectability of a variety of spinal tumors by reducing intraoperative blood loss. This may provide an additional benefit by reducing the risk related to postoperative transfusion. By permitting a more aggressive surgical approach, the use of preoperative embolization also has the potential to improve outcome in patients with spinal tumors.

Adult↗
PubMed1990

Craniofacial trauma: an assessment of risk related to timing of surgery.

Following the retrospective analysis of approximately 4000 head-injury patients, 49 were identified with a combination of displaced facial fractures and significant cerebral trauma. The purpose of this study was to define clinical and radiographic features in these patients that are associated with a poor prognosis, which in turn might influence the timing of facial fracture repair. The presence of an upper-level facial fracture, low Glasgow coma score, intracranial hemorrhage, displacement of normally midline cerebral structures, and multisystem trauma was associated with a statistically significant poorer prognosis. Additionally, in demographically similar groups of patients (age, sex, concomitant injury) preselected for intracranial pressures of less than 15 mmHg at the time of surgery, no significant difference in survival was appreciated in patients who underwent early (0 to 3 days), middle (4 to 7 days), or late (greater than 7 days) surgical repair. Early surgical repair of facial fractures in these circumstances does not appear to have a negative impact on recovery.

Adolescent↗
PubMed1989

Cranial vault growth in craniosynostosis.

Skull growth after single suture closure was described in 1851 by Virchow, who noted that growth in the plane perpendicular to a fused suture was restricted. However, this observation failed to predict compensatory growth patterns that produce many of the deformities recognized as features of individual syndromes. The deformities resulting from premature closure of a coronal, sagittal, metopic, or lambdoid suture can be predicted on the basis of the following observations: 1) cranial vault bones that are prematurely fused secondary to single suture closure act as a single bone plate with decreased growth potential; 2) asymmetrical bone deposition occurs mainly at perimeter sutures, with increased bone deposition directed away from the bone plate; 3) sutures adjacent to the prematurely fused suture compensate in growth more than those sutures not contiguous with the closed suture; and 4) enhanced symmetrical bone deposition occurs along both sides of a non-perimeter suture that is a continuation of the prematurely closed suture. These observations regarding growth in craniosynostosis are illustrated with clinical material in this report.

Cranial Sutures↗
PubMed1988

A study of the functional elements regulating capillary perfusion in striated muscle.

The microcirculatory anatomy of the hamster tibialis anterior muscle is based on modules (units) consisting of groups of 12-20 capillaries which run parallel to muscle fibers. The units are supplied by a common terminal arteriole and drained by a common terminal venule; a single terminal arteriole commonly supplies two microvascular units or a "unit pair." Regulation of the tibialis muscle microcirculation was investigated in pentobarbital-anesthetized hamsters using epifluorescence microscopy. We examined the patterns of capillary control in response to physiological and pharmacological stimuli including elevation of superfusate oxygen content, direct muscle stimulation, and topical application of phenylephrine. Changes in capillary perfusion were rarely manifested as responses of individual capillaries. The predominant response consisted of a coordinated change in virtually all the capillaries of a unit pair. For example, gradual elevation of superfusate PO2 resulted in simultaneous arrest or "derecruitment" of capillary flow in all capillaries of a unit pair in 37 of 43 such elements studied. In the 6 unit pairs showing atypical behavior, no more than four individual capillaries showed atypical behavior. Capillaries in 28 of 29 unit pairs were also recruited during muscle stimulation as members of a unit pair. In 18 of 21 unit pairs, exposure to topical phenylephrine resulted in simultaneous arrest of capillary flow in all capillaries of a unit pair. These data suggest that in this striated muscle, regulation of capillary perfusion is accomplished by control of capillary unit pairs. Accordingly, the patterns of interdigitation of units will ultimately determine the precision of control of tissue diffusion distance as well as oxygenation.

Animals↗
PubMed1988

Lambdoid synostosis: surgical considerations.

Premature closure of the lambdoid suture may result in abnormalities in skull shape not only in the parieto-occipital region, but also in the frontal region and at the vertex of the skull. Although most of these abnormalities are mild, some constitute significant abnormalities in shape and therefore require specific surgical correction. In this report, we describe our approach from five patients we have treated and followed for 6 to 24 months with abnormalities characteristic of unilateral and bilateral lambdoid synostosis. We describe our approach to the simultaneous correction of frontal, occipital, and abnormal vertical height skeletal abnormalities in one operative procedure. To date, no negative neurologic sequelae have resulted from this operative approach, but significant improvement in skull form has been appreciated.

Craniosynostoses↗
PubMed1987

Cervical meningocele and associated spinal anomalies.

Simple meningoceles are infrequent forms of dysraphism and are often benign. They have been associated with other spinal anomalies. The uncommon cervical meningocele may have a higher propensity to be associated with other spinal anomalies. Four patients with cervical meningocele are presented with radiographic evaluation and clinical course. Multiple abnormalities were documented radiographically and operatively, including hydrocephalus, Chiari malformation, hydromyelia, lipomeningomyelocele, tethered cord, thickened filum terminale, diastematomyelia, Klippel-Feil syndrome, and thoracic hemivertebrae. Prior to the development of any late neurological abnormality from associated spinal anomalies, magnetic resonance imaging is recommended early in a child born with a simple meningocele.

Abnormalities, Multiple↗
PubMed1987

Late surgical treatment of unilateral coronal synostosis using methyl methacrylate.

Three techniques combining the shaping of calvarial and facial bone with onlay of methyl methacrylate are presented for use in the late treatment of unilateral coronal synostosis deformities. The procedures described are suggested as possible alternatives to extensive bone repositioning procedures. They have the advantage of being quicker and are therefore potentially safer operations. Acrylic is malleable and does not resorb; thus, permanent superior esthetic results may be achieved. The two most serious risks when using this technique are infection and limitation of growth. The risk of infection may be reduced by attaching the acrylic implant securely to surrounding bone, under sterile conditions, beneath well-vascularized skin. Growth limitation may be obviated by not placing acrylic across sutures in children with enlarging skulls.

Adult↗
PubMed1986

Surgical approaches for the correction of metopic synostosis.

Premature closure of the metopic suture results in a deformity ranging from a minor variation to a severe cosmetic deformity. The three principal abnormalities comprising metopic synostosis are trigonocephaly secondary to the restriction of growth of both frontal bones, deficient lateral supraorbital rims, and hypotelorism. Seventeen of 18 patients evaluated for metopic synostosis had surgical correction of their anomalies. For a minor degree of prominence at the metopic suture, a bicoronal flap followed by shaping at the suture with a shaping burr was sufficient and yielded favorable cosmetic results. A more extensive procedure for cosmetic resolution of trigonocephaly and hypotelorism was required for those patients with more pronounced deformities. In patients with moderate to severe metopic synostosis, the following procedures were important in achieving excellent cosmetic results: a bicoronal subgaleal flap down to the supraorbital rims with preservation of continuity of pericranium with an intact periorbita; bifrontal craniotomy with complete removal of the metopic suture; dural plication in midline to achieve an immediate aesthetically pleasing contour; removal or remodeling of the supraorbital rims and nasion with replacement of the remodeled frontal bone anteriorly in order to rebuild the orbital rim and release the supraorbital bar from the anterior cranial base; and securement of the bifrontal bones anteriorly and laterally, but not posteriorly, to allow further anterior and lateral displacement of the supralateral orbital margin.

Craniosynostoses↗
PubMed1986

Spinal cord arteriovenous malformation in a neonate. Case report.

A 2-day-old neonate with a spinal cord arteriovenous malformation developed severe paraparesis. The abrupt neurological deterioration was not associated with hemorrhage or aneurysmal dilatation. Ischemic damage of the spinal cord is suggested as the cause of the clinical manifestation.

Arteriovenous Malformations↗