A quantitative analysis of orbital soft tissue in Graves' disease based on B-mode ultrasonography

Using B-mode ultrasonography, an attempt was made to measure the volume of extraocular muscles and retrobulbar fat in 31 patients (62 orbits) with Graves' disease. None of the patients had exophthalmometric measurements greater than 21 mm or had eye symptoms. The mean value of muscle volume of Graves' patients was significantly larger than that of normal controls (6.48 +/- 2.70 cm3 and 3.25 +/- 1.30 cm3, respectively, p less than 0.001). All of the patients had extraocular muscle swelling, although 2 of them had no extraocular muscle change for their unilateral eye. The extraocular muscle volume increased as the degree of the proptosis increased. The fat volume tended to increase in parallel with the degree of the proptosis. In the Graves' group with obvious proptosis (Hertel reading: 19--21 mm), the fat volume increased more significantly than in any other group. The ratio of extraocular muscle volume to retrobulbar fat volume was significantly higher in Graves' disease, but it did not increase as the degree of the proptosis increased. A significant correlation between proptosis and muscle volume plus fat volume was observed. No significant difference of the extraocular muscle volume was observed between the patients untreated and treated with antithyroid drugs. The data show a uniform enlargement of the extraocular muscles in Graves' disease and also suggest an involvement of increased retrobulbar fat volume in a group of obvious exophthalmos. The degree of the proptosis is in aclose proportion ot the quantitative change of the orbital soft tissue.     

Assessment of intraorbital structure volume using a numerical segmentation image technique (NSI): the fatty tissue and the eyeball

INTRODUCTION: Measurement of the degree of exophthalmos is one of the main methods used in the assessment of pathological processes that occur in the orbital space and is widely used. However, this only provides initial information about the volume relations between the intraorbital structures. The aims of our work were as follows: to draw up a new computer application, namely the numerical segmentation image (NSI) technique, for the automatic calculation of the volume of the intraorbital structures on the basis of magnetic resonance imaging (MRI) images, to determine its usefulness in the segmentation of fatty tissue and the eyeball and to estimate their volume in relation to the degree of exophthalmos. MATERIAL AND METHODS: A total of 45 patients (90 orbits) were included in the study. All the patients underwent MRI examination of the orbits by a 1.5 T scanner using a head coil. The degree of exophthalmos was determined clinically and radiologically in relation to the interzygomatic line. Quantitative assessment of the eyeball and fatty tissue was made using an NSI application. RESULTS: The influence of fatty tissue volume on the degree of exophthalmos was determined as being statistically significant (r = 0.367, p = 0.000374) but was smaller in comparison with the relationship between total eye muscle volume and degree of exophthalmos; eyeball volume was found to have the least influence (r = 0.344, p = 0.000374). Two eyeballs of significantly smaller volume were found in the group of 90 orbits analysed. CONCLUSIONS: The NSI technique is a clinically useful application, providing objective data calculated individually for each orbit. A credible protocol for estimating the degree of exophthalmos on the basis of the NSI technique should include the eye muscle volume, fatty tissue volume and, in cases where eyeball pathologies coexist, the eyeball volume as well.     

A congenital orbital defect with periorbital-dural tissue adhesion

This case demonstrates a previously unreported congenital orbital deformity. The patient was born with a unilateral exophthalmos. The etiology of the defect was demonstrated by CT scan as a convex bowing of the right superomedial orbital wall behind the axis of the eye. At surgery, this convexity was revealed to be a small bony defect through which the periorbital tissue and dura mater adhered. This sort of orbital deformity, although subtle, must be considered in the differential diagnosis of congenital unilateral exophthalmos.     

Use of immobilized Candida cells on xylitol production from sugarcane bagasse

In this study we used the yeast Candida guilliermondii FTI 20037 immobilized by entrapment in Ca-alginate beads (2.5-3 mm diameter) for xylitol production from concentrated sugarcane bagasse hemicellulosic hydrolysate in a repeated batch system. The fermentation runs were carried out in 125- and 250-ml Erlenmeyer flasks placed in an orbital shaker at 30 degrees C and 200 rpm during 72 h, keeping constant the proportion between work volume and flask total volume. According to the results, cell viability was substantially high (98%) in all fermentative cycles. The values of parameters xylitol yield and volumetric productivity increased significantly with the reutilization of the immobilized biocatalysts. The highest values of xylitol final concentration (11.05 g/l), yield factor (0.47 g/g) and volumetric productivity (0.22 g/lh) were obtained in 250-ml Erlenmeyer flasks containing 80 ml of medium plus 20 ml of immobilized biocatalysts. The support used in this study (Ca-alginate) presented stability in the experimental conditions used. The results show that the use of immobilized cells is a promising approach for increasing the xylitol production rates.     

Surgical correction of exophthalmos secondary to Graves' disease

Graves' disease has been recorded in the medical literature for more than 150 years. Despite introduction of iodine into the diet, Graves' disease still remains the most important disorder of the thyroid gland. Clinically, Graves' disease is a multisystem disorder of unknown etiology characterized by the clinical triad of infiltrative pretibial dermopathy, thyroid glandular hyperplasia, and ophthalmopathy. Expansion of the bony orbital volume is an effective method of treating moderate to severe exophthalmos. Our experience with a simplified version of a three-wall orbital decompression to correct exophthalmos secondary to Graves' disease is presented.     

Assessment of the volume of intraorbital structures using the numerical segmentation image technique (NSI): the extraocular muscles

INTRODUCTION: In recent years the use of computer systems has allowed numerical analysis of medical images to be introduced and has speeded up the conversion of numerical data into clinically valuable information. The creation of a software application that could almost automatically calculate the volume of anatomical structures imaged by MRI has seemed possible. The aim of our study was to determine the clinical usefulness of an numerical segmentation image technique (NSI) software application in estimating the volume of extraocular muscles. MATERIAL AND METHODS: The study group was formed of 45 patients (90 orbits). All the patients underwent MRI examinations of the orbits by a 1.5 T scanner using a head coil. The degree of exophthalmos was determined clinically and radiologically in relation to the interzygomatic line. The quantitative assessment of all eye muscles was carried out using the NSI application, a new software program introduced by the authors. RESULTS: A close correlation between muscle volume and the degree of exophthalmos was revealed and confirmed by statistical analysis (r = 0.543, p = 3.13396E-08) in agreement with other papers. CONCLUSIONS: The NSI software program is an application which offers a reliable and precise estimation of eye muscle volume. It is therefore useful in the diagnosis of the pathological processes leading to exophthalmos. It has special clinical value for monitoring discrete volume changes of muscles during treatment.     

Upper blepharoplasty with bony anatomical landmarks to avoid injury to trochlea and superior oblique muscle tendon with fat resection.

The trochlea and superior oblique muscle tendon separate the medial and central fat compartments in the upper lid. The purpose of this study was to determine anatomical landmarks to predict the location of and avoid injuring the trochlea and superior oblique muscle tendon with orbital fat resection during upper blepharoplasty. The trochlea and superior oblique muscle tendon were identified in 14 cadaver heads. Bony anatomical landmarks were identified to predict the oblique vector along which the trochlea and superior oblique tendon lie. The trochlea was measured in millimeters from the palpable superior orbital foramen. The oblique course of the superior oblique muscle tendon was measured from its medial location in the lateral direction in millimeters from the frontozygomatic suture. These measurements were obtained with 4.0-power loupe magnification. The trochlea was identified 10.0 +/- 0.9 mm inferior to the palpable superior orbital foramen. The superior oblique muscle tendon coursed laterally along an oblique vector to within 1 mm of the frontozygomatic suture for all 14 dissections. The vertical vector of the superior orbital foramen was measured 15.9 +/- 1.1 mm lateral to the medial canthus. The width of the bony orbit measured 42.2 +/- 1.6 mm. In two dissections, the superior orbital foramen could not be palpated, and the latter measurements were used to predict the superior orbital foramen. This anatomical study showed that when performing orbital fat resection with upper blepharoplasty, the trochlea and superior oblique muscle tendon can be identified and avoided with the above-described bony landmarks.     

Surgical treatment of thyrotoxic exophthalmos

Conservative treatment of thyrotoxic exophthalmos has not given satisfactory results. Our observations, modifications of the standard surgical technique, and the results of orbital decompression for this condition are presented. Through a transverse incision close to the lower eyelid margin, the floor and the lateral orbital wall are explored. The posterior part of the orbital floor and the zygomatic part of the lateral orbital wall, as well as the periorbital fat, are removed. Through an incision made over the medial margin of the orbit, the medial orbital wall is explored and its ethmoidal part is removed. By the same approach, further retrobulbar fat is removed. Through an upper eyelid incision, fat is removed from the eyelid region and the levator aponeurosis is divided. This produces satisfactory symmetrical decompression of the orbit with good correction of exophthalmos and a significant decrease in the signs and symptoms of this condition.     

Exercise-induced swelling of rat soleus muscle: its relationship with intramuscular pressure

Exercise-induced tissue swelling and its possible consequence for tissue pressure were studied in rat soleus muscle. Rats ran for 75 min on a belt with a 10 degree positive incline. Wet weights of cryofixed soleus muscles were increased at 3 (16%), 6 (28%), 9 (16%), and 24 (16%) h after running compared with those of nonexercised controls. The transient increase in muscle wet weight correlated in time with an increase in muscle volume. Muscle fiber swelling accounted for most of the muscle swelling in absolute terms because of the large proportion (approximately 90%) of the muscle volume composed of fibers, but swelling of the interstitium was about twofold larger than fiber swelling per unit area. Muscle fiber degeneration was most frequently found at the end of the observation period, i.e., 24 h after running. The muscle swelling was not associated with an increase in intramuscular pressure. During the postexercise measuring period (18 min to 24 h after exercise), intramuscular pressures of exercised rats (1.3 +/- 0.3 mm Hg) did not differ significantly from control values (1.0 +/- 0.2 mm Hg). These findings indicate that increased intramuscular pressure is not responsible for the muscle fiber degeneration found in rat soleus muscle 24 h after endurance running.     

Lower blepharoplasty using bony anatomical landmarks to identify and avoid injury to the inferior oblique muscle

In the resection of redundant orbital fat during lower blepharoplasty, selective excision is performed from the medial, central, and lateral compartments. During transcutaneous blepharoplasty, the inferior oblique muscle is susceptible to injury because of its intimate association between the medial and central compartments. When performing a transconjunctival approach, the inferior oblique muscle is even more susceptible to injury because it lies in the direct path of dissection for fat pad exposure. Injury to the inferior oblique muscle can result in symptoms ranging from transient diplopia to a more debilitating permanent strabismus. Fresh cadaver heads were used to identify bony anatomical landmarks that would help to more accurately define the origin and body of the inferior oblique muscle. The orbital rim, infraorbital foramen, and supraorbital notch were chosen as guideline landmarks. The origin of the inferior oblique muscle was designated with respect to the above structures, and the muscle course was delineated. The inferior oblique muscle originates on the orbital floor, 5.14 +/- 1.21 mm posterior to the inferior orbital rim, on a line extending from the infraorbital foramen to 10 +/- 0.9 mm inferior to the supraorbital notch along the supramedial orbital rim. The muscle belly extends from this origin to its insertion into the posterolateral globe in an oblique direction toward the lateral canthal area. Identification of the orbital rim, infraorbital foramen, and supraorbital notch more accurately localizes the origin and course of the inferior oblique muscle, which may facilitate fat resection during lower blepharoplasty by preventing morbidity associated with inferior oblique muscle injury.     

Orbital volume measurements in enophthalmos using three-dimensional CT imaging

The purpose of this study was to investigate enophthalmos by measuring the volume of various orbital structures using off-line computer techniques on images generated by a CT scanner. Eleven patients with enophthalmos had CT scans of the orbits consisting of 30 to 40 adjacent 1.5-mm slices. The data from the scans were analyzed on a Nova 830 stand-alone computer system using software programs that allowed measurement of total bony orbital volume, total soft-tissue volume, globe volume, orbital fat volume, neuromuscular tissue volume, and apex-to-globe distance in the horizontal plane. These data were analyzed comparing the volumes in the normal eye with the volumes in the enophthalmic eye in each patient. The analysis demonstrated a statistically significant increase in bony orbital volume in the enophthalmic eye, but the total soft-tissue volume, fat volume, neuromuscular tissue volume, and globe volume were the same as in the normal eye. The apex-to-globe distance, a measure of the degree of enophthalmos, was less in the enophthalmic eye than in the normal eye. These results suggest that in the majority of patients, the cause of posttraumatic enophthalmos is increased bony orbital volume rather than by soft-tissue loss or fat necrosis. (Several patients showed no volume discrepancies, and it is likely that cicatricial contracture is responsible for the enophthalmos in these cases.) This study suggests that the objective of surgery for correction of enophthalmos in patients with a volume discrepancy should be to decrease the volume of the bony orbit and to increase the anterior projection of the globe.     

Computer-assisted secondary reconstruction of unilateral posttraumatic orbital deformity

Until now, computer-assisted surgery has not been practiced as part of the surgical routine of posttraumatic orbital reconstruction. The purpose of this study was to investigate the use of a navigation system for computer-assisted preoperative planning with virtual reconstruction to obtain symmetry of the orbits and intraoperative control of virtual contours in comparison with the clinically achieved surgical results. A further objective of the computer-assisted orbital analysis was to use an ideal measurement for the two-dimensional and three-dimensional changes following orbital reconstruction and to check the equality of the postoperative values for the affected orbits in comparison with those of the unaffected sides. Patients with unilateral posttraumatic orbital defects (n = 18) underwent computer-assisted surgery and preoperative planning using a spiral computed tomography database. Surgical procedures were preplanned with virtual correction by mirroring an individually defined three-dimensional segment from the unaffected side onto the deformed side, creating an ideal unilateral reconstruction. These computer-models were intraoperatively used as virtual templates to navigate the preplanned contours and the globe projection using the Stryker-Leibinger navigation system. Individual noninvasive registration with an overall inaccuracy of approximately 1 mm was achieved by using a maxillary occlusal splint with four markers. The mirroring of the unaffected side allowed an ideal virtual reconstruction. A mean decrease in enlarged orbital volume of 4.0 (SD +/- 1.9) cm was achieved, as was a mean increase in the sagittal globe projection of 5.88 (SD +/- 2.98) mm. With a paired Student test, the decrease between the preoperative and postoperative differences of the affected and unaffected sides was proved significant for orbital volume, globe projection, and computed tomography-based Hertel scale changes (p < 0.01). In 15 of 18 cases, simultaneous malar bone advancement resulted primarily in an additional increase in orbital volume before intraorbital augmentation with calvarial split-bone grafts could be performed. Intraorbital bony augmentation included one (n = 1), two (n = 7), three (n = 8), and all four (n = 2) orbital walls. Computer-assisted preoperative planning enables the surgeon to predict reconstructive surgical steps before the operation. Highly vulnerable structures such as the optic nerve can be detected and avoided intraoperatively, and virtually preplanned bone graft positions and/or orbital frame contours can be checked. Computer-assisted preoperative planning and surgery thus advance the difficult surgical field of orbital reconstruction, particularly through a greater exploitation of radiologic information without additional radiation to the patient.     

EXOPHTHALMOS—From the Standpoint of the Otolaryngologist

Exophthalmos may be due to an inflammatory process or to tumor formation. Inflammatory processes are most likely to occur in children and young adults. Tumors are the most common cause of exophthalmos in adults.Since the advent of chemotherapy and the antibiotics, rarely does orbital cellulitis develop from sinal infection.Tumors causing exophthalmos are likely to be benign if they arise from the frontal sinus and malignant if they arise from the maxillary and ethmoid sinuses.     

Exophthalmos from the standpoint of the otolaryngologist

Exophthalmos may be due to an inflammatory process or to tumor formation. Inflammatory processes are most likely to occur in children and young adults. Tumors are the most common cause of exophthalmos in adults.Since the advent of chemotherapy and the antibiotics, rarely does orbital cellulitis develop from sinal infection. Tumors causing exophthalmos are likely to be benign if they arise from the frontal sinus and malignant if they arise from the maxillary and ethmoid sinuses.     

Modified three-wall orbital expansion to correct persistent exophthalmos or exorbitism.

It is believed that a variation of the 3-wall orbital expansion of Tessier can be used to correct persistent exophthalmos, as well as exorbitism. The operation is described, and the results in 3 patients are shown.     

Spinal stiffness changes throughout the respiratory cycle.

Posteroanterior stiffness of the lumbar spine is influenced by factors, including trunk muscle activity and intra-abdominal pressure (IAP). Because these factors vary with breathing, this study investigated whether stiffness is modulated in a cyclical manner with respiration. A further aim was to investigate the relationship between stiffness and IAP or abdominal and paraspinal muscle activity. Stiffness was measured from force-displacement responses of a posteroanterior force applied over the spinous process of L2 and L4. Recordings were made of IAP and electromyographic activity from L4/L2 erector spinae, abdominal muscles, and chest wall. Stiffness was measured with the lung volume held at the extremes of tidal volume and at greater and lesser volumes. Stiffness at L4 and L2 increased above base-level values at functional residual capacity (L2 14.9 N/mm and L4 15.3 N/mm) with both inspiratory and expiratory efforts. The increase was related to the respiratory effort and was greatest during maximum expiration (L2 24.9 N/mm and L4 23.9 N/mm). The results indicate that changes in trunk muscle activity and IAP with respiratory efforts modulate spinal stiffness. In addition, the diaphragm may augment spinal stiffness via attachment of its crural fibers to the lumbar vertebrae.     

The surgical management of orbital neurofibromatosis

Orbitofacial neurofibromatosis may cause severe soft-tissue deformity along with pulsating exophthalmos. The orbit is enlarged, and the greater wing of the sphenoid is absent. The eye in some cases may be functionally useless, immobile, displaced, and blind. In these, orbital exenteration with soft-tissue excision and orbital reconstruction is recommended. External cover is provided by the thin eyelid skin, and a prosthesis ultimately allows a very satisfactory end result. Four such cases with a minimum of 2 years of follow-up are presented.     

Eye muscle antibodies in endocrine exophthalmos. Clinical and serological observations

Serum samples were obtained from 65 patients with endocrine exophthalmos class I-V. In 33/65 patients who were treated either with prednisone or with ciclosporin, blood was sampled before, during and after therapy. Antibodies against eye muscle were determined during the course of immunosuppressive therapy in order to have an objective parameter of the therapeutic effect. To ascertain the specificity of the reaction both eye and abdominal muscles were used as antigens in an ELISA system. Both IgG and IgM antibodies were detected. In 45/65 patients (71%) eye muscle antibodies were positive before starting therapy. Antibodies were mostly detected in patients with active disease. Patients with exophthalmos of recent onset always had IgM antibodies whereas patients with chronic exophthalmos were mostly IgG positive. Patients with relapse showed mostly IgG but also IgG and IgM positivity in 2 cases. In 58% of cases only IgG antibodies were found whereas in 34% both IgG and IgM were detected and in 8% only IgM antibodies. There was no association between antibodies directed against eye muscle and thyroid microsomal and thyroglobulin antibodies or with the state of thyroid function. Furthermore there was no correlation between exophthalmos classes and eye muscle antibody binding activity. The antibody level declined during therapy with prednisone or with ciclosporin but rose again 8-12 weeks after stopping the drug in patients with progressive disease.     

Shaken helical track bioreactors: Providing oxygen to high-density cultures of mammalian cells at volumes up to 1000 L by surface aeration with air

A new scalable reactor was developed by applying a novel mixing principle that allows the large-scale cultivation of mammalian cells simply with surface aeration using air owing to increased liquid-gas transfer compared to standard stirred-tank bioreactors. In the cylindrical vessels (50 mL-1500 L) with a helical track attached to the inside wall, the liquid moved upward onto the track as the result of orbital shaking to increase the liquid-gas interface area significantly. This typically resulted in a 5-10-fold improvement in the volumetric mass transfer coefficient (k(L)a). In a 1500-L helical track vessel with a working volume of 1000 L, a k(L)a of 10h(-1) was obtained at a shaking speed of 39 rpm. Cultivations of CHO cells in a shaken 55-L helical track bioreactor resulted in improved cell growth profiles compared to control cultures in standard systems. These results demonstrated the possibility of using these new bioreactors at scales of 1000 L or more.     

Mechanisms of global support and posttraumatic enophthalmos: I. The anatomy of the ligament sling and its relation to intramuscular cone orbital fat

The mechanisms of posttraumatic enophthalmos were evaluated to determine the interrelation between fat and ligaments in globe support. Anatomic studies demonstrate that the ligaments form an essential "sling" framework for the globe but are alone insufficient to maintain the globe's full forward position. Removal of extramuscular fat in cadavers and in patients undergoing blepharoplasty did not significantly change globe position. Loss of intramuscular cone fat (atrophy or displacement) in cadavers and patients produced enophthalmos. Fat atrophy is not a prominent feature in most patients with posttraumatic enophthalmos. Some loss of intramuscular cone fat from displacement outside the muscle cone is frequently present. The principal mechanism, however, of posttraumatic enophthalmos involves a displacement and change in the shape of orbital soft tissue. Loss of bone and ligament support permits posterior displacement and a reshaping of orbital soft tissue under the influence of gravity and the remodeling forces of fibrous scar contracture. The shape of the retrobulbar orbital contents changes from a modified cone to a sphere, and the globe sinks backward and downward. Given that the volume of orbital soft tissue is constant following trauma, procedures to restore the shape and position of the orbital soft tissue by mobilization and bone reconstruction will correct or significantly improve enophthalmos.