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Biomedical subjects

F W Zonneveld

Publications and source records attributed to F W Zonneveld.

At least 19 recordsLinked to original sources
PubMed1995

Dehiscence of the jugular bulb in Crouzon's disease.

Patients with Crouzon's disease have a distorted nasopharynx, which frequently leads to retained middle ear secretions and necessitates myringotomy. A review of the computed tomographic (CT) scans of 21 ears in 11 patients with Crouzon's disease found that 12 jugular bulbs were protruding or dehiscent. The relationship between the jugular bulb and the middle ear space was normal bilaterally in only 2 of the 11 patients. Consequently, patients with Crouzon's disease are at risk for inadvertent puncture of the jugular bulb during myringotomy. CT scans obtained prior to myringotomy can be helpful in detecting dehiscent or protruding jugular bulbs.

Adolescent↗
PubMed1991

[Conservative therapy frequently indicated in blow-out fractures of the orbit].

The results of the conservative approach in the management of patients with orbital blow-out fractures were studied at the Orbital Centre, Amsterdam. In 54 out of 111 patients with a pure blow-out fracture, high resolution CT was performed. In these 54 patients with diplopia, clinical examination together with the analysis of direct multiplanar high resolution CT revealed four cases of impaired motility. These were oedema, oculomotor nerve palsy, enophthalmos and adhesions around the lower eye muscles and the orbital floor. Patients were immediately instructed to exercise eye movements thoroughly. If diplopia did not resolve, further management was decided on. In all patients with edema or oculomotor nerve palsy, diplopia resolved spontaneously. Surgery was necessary to reduce diplopia in the enophthalmos and adhesion groups. This study shows that eye movement exercises together with a 'wait and see' approach diminish the number of operations by 50% in patients with pure blow-out fractures. It also circumvents the iatrogenic adhesions between eye muscles and orbital floor, which are difficult to treat.

Combined Modality Therapy↗
PubMed1991

Intradiploic epidermoid cysts of the bony orbit.

Epidermoid cysts originating within the diploic space of the bony orbit are rare. The authors retrospectively studied four patients with an intradiploic epidermoid cyst of the orbital bones to investigate the clinical and the computed tomographic (CT) findings. The clinical presentation was dependent on the location of the slowly expanding epidermoid cyst. The sphenoid bone was involved in three patients and the frontal bone in one patient. Proptosis caused by intraorbital extension of the mass was the most common presenting sign. The findings on high-resolution CT scans appeared to be specific for intradiploic epidermoid cysts. The typical sclerotic margin, which is diagnostic of intradiploic epidermoid cysts, can be demonstrated by CT scans with a bone window setting.

Adolescent↗
PubMed1991

Primary and secondary implants in the anophthalmic orbit. Preoperative and postoperative computed tomographic appearance.

Sagittal computed tomographic (CT) scans of 10 anophthalmic orbits with a primary implant, an acrylic ball covered with donor sclera, and 10 anophthalmic orbits before and after insertion of a secondary implant were studied. For each patient, the scans of the anophthalmic and contralateral normal orbit were compared. In the anophthalmic orbits, the anatomy was optimally restored in those with a primary implant, and suboptimal results were achieved in the orbits with a secondary implant. The greatest differences were noticed in the orbits without an implant. Differences were noticed for the position and length of the superior muscle complex and the inferior rectus muscle, the position of the upper eyelid, the depth of the superior sulcus, and the backward tilt of the prosthesis. The authors conclude that the rotatory displacement of the orbital contents after enucleation, which explains the sequelae of the anophthalmic orbit, is grossly circumvented by the insertion of an implant. In achieving this effect, primary implants are better than secondary ones.

Adolescent↗
PubMed1991

Prosthesis motility with and without intraorbital implants in the anophthalmic socket.

Ocular prosthesis motility was measured and compared in 15 patients with a primary baseball implant after enucleation of an eye, in 11 patients with a secondary baseball implant, in 12 patients with an Allen implant, and in 11 patients without any intraorbital implant. In all patients a noticeable lag of movement of the prosthetic eye was measured: in the extreme directions of gaze the excursions of the prosthesis were far less in comparison with the contralateral normal eye. For normal eye movement round the primary position of gaze, however, the prosthesis motility in the primary baseball and Allen implant group appeared to be sufficient to give a lifelike appearance. The average motility of the prostheses in these two groups did not differ. The motility in the secondary baseball group and in the group without an implant was evidently worse. In the last group the prosthesis motility was most impaired. We conclude that the insertion of an implant, even when inserted some time after the enucleation (a secondary implant), improves the motility of the prosthesis markedly. We recommend the primary baseball implant as the correction of choice after enucleation.

Adolescent↗
PubMed1991

Conjunctival cysts in anophthalmic orbits.

Five out of 149 patients (3%) who received an intraorbital implant to prevent or treat the disfiguring symptoms associated with the postenucleation socket syndrome developed intraorbital conjunctival cysts. All five patients had received a secondary implant two 14 months previously. After excision of the cysts four patients required additional surgery for lack of conjunctiva and/or recurrent cyst formation. The clinical findings, mechanism of development, and management of this rare but serious complication of socket surgery are described.

Adult↗
PubMed1990

Applications of three-dimensional display techniques in medical imaging.

This paper outlines some of the current uses of three-dimensional techniques in medical imaging applications and their potential for the future. As an example, three-dimensional imaging is described using a CT scanner, as it applies to a case involving craniofacial surgery. This includes defining the relationship between the requirements on the data acquisition system, as well as the specification of the hardware and software for the display. A currently used algorithm is described for the display of surfaces as a function of local position, orientation of the surface and the position of a virtual light source. This includes the use of transparency and cut plane greyscale techniques, in addition to the display of the surfaces. A speculation is made regarding the use of a three-dimensional display as the standard viewing mode in CT, with slice and multiplanar imaging as submodes.

Algorithms↗
PubMed1990

Computed tomography in the assessment of the postenucleation socket syndrome.

To gain a deeper insight into the cause of the postenucleation socket syndrome, high-resolution computed tomography (CT) was performed in 22 anophthalmic patients before insertion of an intraorbital implant. The anatomy of the normal and the anophthalmic orbits was compared. Computed tomographic scans were made either in the sagittal and the coronal plane or in the sagittal and transverse plane. The authors discovered a sagging and retraction of the superior muscle complex and a downward and forward redistribution of orbital fat. Finally, an upward displacement of the distal end together with a retraction of the inferior rectus muscle was found. These phenomena were measured and appear to cause a rotatory displacement of orbital contents from superior to posterior and from posterior to inferior which is best demonstrated in the sagittal plane. This redistribution of orbital contents can explain the sequelae of the anophthalmic orbit. No signs of orbital fat atrophy could be demonstrated. With this knowledge, the proper treatment of patients with a postenucleation socket syndrome is ascertained.

Adult↗
PubMed1987

Grease-gun injury of the orbit: computed tomography and magnetic resonance imaging in diagnosis and treatment.

A 19-year-old male was referred because of a grease-gun injury of the left orbit, resulting in a 25 mm proptosis and marked decrease in vision. The clinical diagnosis of penetration of the retrobulbar fat space by the grease and the subsequent accurate drainage of the grease was made possible on the basis of high resolution computed tomography (CT) and magnetic resonance imaging (MRI). As a result, lateral orbitotomy could be avoided. Eight months after the injury the visual acuity was fully recovered and the proptosis reduced to 2 mm. The visual field was relatively undisturbed. The specific value of CT and MRI for the management of this unusual trauma is briefly discussed.

Adult↗
PubMed1987

The role of direct multiplanar high resolution CT in the assessment and management of orbital trauma.

Basic anatomic research has resulted in the discovery of an intricate intraorbital connective tissue system involved in normal eye movements, and in combination with the development of the direct triplane high-resolution CT technique, this research has dramatically improved the treatment of orbital trauma. On the basis of clinical and CT evaluation, four causes of motility impairment after orbital trauma are now recognized and permit patient-tailored treatment methods.

Accidents, Traffic↗
PubMed1986

Direct coronal and direct sagittal CT of abdomen and pelvis: an approach to staging malignancies.

Direct coronal and sagittal CT images are of high quality and are applicable to a majority of patients in daily practice. Because of the fact that transverse scans alone can be misleading, direct CT images in two or more different planes greatly enhance one's capability to stage neoplasms that are complex and extensive. The integrity of the margins of an organ, in the presence of tumor, is best determined by coronal or sagittal scanning. Lesions of the adrenal and kidney and retroperitoneal processes with possible extension into liver or other adjacent organs can be evaluated best using the combination of transverse and coronal or sagittal scans of the upper abdomen. Depending on the origin of pelvic lesions, the radiologist must consider in every individual case the performance of either direct coronal or sagittal sections or both. This judgment is based on the findings on the transverse scans, understanding of anatomic relationships of the pelvic viscera and knowledge of staging systems and their implications with respect to therapeutic decisions. In such a tailored approach, multiplanar CT facilitates improved presurgical evaluation. In some cases, the true extent of the lesion can only be seen in the coronal or sagittal planes. A potential new role for direct multiplanar CT is that it may be used as a sort of "gold standard" for the analysis of multiplanar ultrasound and MRI studies.

Abdominal Neoplasms↗
PubMed1986

Patient positioning for direct sagittal CT of the orbit parallel to the optic nerve.

A patient positioning technique for midsagittal brain scanning was modified to allow for direct sagittal computed tomography examinations of the orbit parallel to the optic nerve. High-resolution, artifact-free images are obtained that clearly depict all vital interfaces in sagittal cross sections. This technique is applicable to nearly all patients and does not present the many disadvantages of multiplanar reformating.

Brain↗