Surgical anatomy of the superior orbit on ultra-high-resolution MRI at 9.4 Tesla.

BACKGROUND: A good understanding of the anatomical details is required to ensure optimal results during surgery of the orbit. Several indications for orbital surgery require biopsy, resection, or reconstructive procedures. The intricate relationships between the orbital septum and adjacent structures of the upper orbit can cause difficulties in interpreting the surgical anatomy of this region. The purpose of this study was to acquire further insight into the anatomy of the superior part of the orbit, with special attention paid to the orbital septum. METHODS: An ex-vivo study was performed using magnetic resonance imaging (MRI) at 9.4 Tesla (isotropic resolution = 20 µm) on six human cadaver specimens to examine the superior-medial half of the orbit. To visualise the posterior layers of the upper orbit, a dissection of three of the orbits was performed prior to the MRI examination, and a flexible PVC sheet was introduced above the levator muscle. RESULTS: The technique enabled a visualisation of anatomically important landmarks of the anterior and posterior parts of the upper orbit at a resolution near histological levels; to the authors' knowledge, this visualisation has not been reported previously. A posterior continuation of the orbital septum, which forms a distinct anatomical structure, is revealed. CONCLUSIONS: The posterior aspect of the orbital septum separates the levator muscle and the orbital fat pad. Between these two structures, a surgical corridor is formed using MRI, enabling alternative access to the superior part of the orbit; this alternative access might be less invasive because the orbital septum remains undamaged.

Suspension surgery with autogenous fascia lata via a less invasive modification of the Crawford method on 85 patients with congenital severe eyelid ptosis.

BACKGROUND: Autogenous fascia lata is considered the gold standard for frontalis suspension surgery to correct severe congenital upper eyelid ptosis. METHODS: This study evaluated the efficacy of a less invasive modification of the standard technique described by Crawford. A total of 85 patients with severe congenital ptosis were enrolled in this study and submitted to surgical correction by frontalis suspension using autogenous fascia lata. Among these patients, 51 had previously undergone ptosis correction using other surgical techniques. The final lid level and contour were evaluated in addition to complications, such as lagophthalmos and ptosis recurrences. RESULTS: Overall, the final results were evaluated as good in 71 of the cases, whereas 11 cases were graded as satisfactory and three cases as poor according to the success criteria. The average increase in eyelid height, measured as the marginal reflex distance (MRD), was 2.9 mm. The best results were obtained in the group of patients with no previous eyelid surgeries. The examples of poor results could be attributed to lagophthalmos and were all confined to the group of patients with a previously failed surgery that employed synthetic suspension materials and levator shortening procedures. No recurrences were observed during the follow-up interval, which lasted an average of 6.4 months (range = 2-59 months). CONCLUSIONS: This technique allows a safe surgery with an overall high rate of success. This surgery is also safe and successful in cases of congenital ptosis with associated abnormalities, such as blepharophimosis, and in cases that require secondary ptosis repair.

Surgical approach to the superior mid-orbit.

Access to the superior mid-orbit is required for procedures on the levator muscle in the correction of upper eyelid ptosis and in surgery aimed at local lesions in this region. The purpose with this human cadaver study was to clarify the anatomical substrate for a surgical approach to the levator muscle and the upper mid-orbit structures, in which the orbital septum and the retroseptal fat pad is not harmed during surgery. Macro-anatomical dissections and histological examinations were performed on five human orbits from three formalin embalmed cadaver heads. It was found that the orbital septum extends posteriorly from its junction with the levator aponeurosis. This posterior continuation of the orbital septum encloses the superior orbital fat pad and separates this from the anterior surface of the levator muscle. In between the orbital septum and the levator, there is a dissection space that provides a minimal invasive access corridor to the structures in the upper mid-orbit.

A modified technique for levator resection in congenital ptosis.

This study describes a modified technique for levator resection in congenital ptosis and presents the results from a consecutive series of patients operated on with this method. Eighteen patients were operated on for congenital ptosis. By means of a blunt dissection through the potential space between the levator aponeurosis and the orbital septum, this operation method takes advantage of this anatomical entrance route to surgery on the levator complex, and thereby avoids violation of the orbital septum and the retroseptal fat pad. In a consecutive series of 18 patients with congenital ptosis, 88% of the patients achieved a good result according to the success criteria. In surgery for moderate congenital ptosis, the amount of levator resection is of utmost importance to obtain the desired height of the eyelid. With this method this can be obtained without violating the orbital septum.

Pilot study on the time course of apoptosis in the regenerating corneal epithelium.

PURPOSE: To determine whether apoptosis contributes to regeneration of the corneal epithelium following erosion and following ultraviolet irradiation. METHODS: Central corneal erosions were made on one eye of 16 rats. One eye of another set of 16 rats was exposed to UVB irradiation. The rats were killed at time intervals varying from 12 hours to 7 days after treatment. Enucleated eyes were fixed in buffered formaldehyde and evaluated by terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate (dUTP) nick-end labelling (TUNEL) and morphology. The total number of cells and the number of TUNEL positive cells were counted in perpendicular sections using light microscopy. RESULTS: Following central erosion the total epithelial cell number was restored by day 3. During the first 5 days, TUNEL positive cells were observed only in small numbers, but an increase occurred by days 6 and 7. After UVB, an increase in TUNEL positive cells was noted for at least 3 days, and by day 7 there was a small increase of TUNEL positive cells. This differed from the results seen in control animals. CONCLUSIONS: The present study indicates that after injury, apoptosis occurs in two distinct phases. There is an initial early phase of apoptosis which subsides at about the time the cell mass is being restored and after damaged cells have been removed. A later phase of apoptosis occurs suggests it has a homeostatic role which contributes to the regulation of the cell population.