Tendon elongation with bovine pericardium in strabismus surgery-indications beyond Graves' orbitopathy

Pericardium decellularization in a one-day, two-step protocol

Scaffolds used in tissue engineering can be obtained from synthetic or natural materials, always focusing the effort on mimicking the extracellular matrix of human native tissue. In this study, a decellularization process is used to obtain an acellular, biocompatible non-cytotoxic human pericardium graft as a bio-substitute. An enzymatic and hypertonic method was used to decellularize the pericardium. Histological analyses were performed to determine the absence of cells and ensure the integrity of the extracellular matrix (ECM). In order to measure the effect of the decellularization process on the tissue's biological and mechanical properties, residual genetic content and ECM biomolecules (collagen, elastin, and glycosaminoglycan) were quantified and the tissue's tensile strength was tested. Preservation of the biomolecules, a residual genetic content below 50 ng/mg dry tissue, and maintenance of the histological structure provided evidence for the efficacy of the decellularization process, while preserving the ECM. Moreover, the acellular tissue retains its mechanical properties, as shown by the biomechanical tests. Our group has shown that the acellular pericardial matrix obtained through the super-fast decellularization protocol developed recently retains the desired biomechanical and structural properties, suggesting that it is suitable for a broad range of clinical indications.

Surgical Outcome After Treatment of Radiation-Induced Scleral Necrosis in Patients With Uveal Melanoma

PURPOSE

Surgical repair might be required in patients with uveal melanoma (UM) that develop advanced forms of radiation-induced scleral necrosis (RISN). In this monocentric long-term observational study, we aimed at analyzing the treatment outcome after RISN surgery.

METHODS

All consecutive cases with UM who underwent surgical intervention for RISN between 1999 and 2020 were included. Achievement of the tectonic stability and evaluation of incidence and the risk factors for a repetitive patch surgery (RPS) were the main endpoints.

RESULTS

The final analysis included 57 patients (mean age: 58.7 years; 63.2% female patients), where 55 individuals underwent a patch grafting, and 2 cases were treated with conjunctival reconstructive surgery. The mean follow-up time after grafting was 38.5 months (0.03-221.1 months). Tectonic stability was achieved in 56 (98.3%) patients. Scleral graft (38/55, 69.1%) was the most frequent patching material, followed by Tutopatch (7/55, 12.7%), corneal graft (7/55, 12.7%), dura graft (2/55, 3.6%), and fascia lata (FL) graft (1/55, 1.8%). Eleven patients (20%) underwent RPS after the mean time of 12.9 months (0.3-50.3 months). In the final multivariate Cox regression analysis, the use of Tutopatch (5/7; 71.4%, adjusted hazard ratio = 4.66, P = 0.044) and RISN progression after patch grafting (9/11; 81.8%, adjusted hazard ratio = 9.67, P = 0.008) were independent risk factors for RPS.

CONCLUSIONS

RISN surgery maintains long-term tectonic stability in most of the cases underwent surgical repair for RISN after brachytherapy for UM. Depending on graft material and, particularly, further RISN progression, an RPS might be necessary in certain cases.

Long-term results of strabismus surgery for treatment of esotropia in patients with Möbius syndrome

PURPOSE

To evaluate the surgical results of Möbius syndrome esotropia following bilateral medial rectus recession with and without bilateral Hummelsheim procedure.

METHODS

The medical records of patients with Möbius syndrome operated on by a single surgeon from 1993 to 2022 were studied retrospectively. For each patient, age, sex, and ocular deviation before and after surgery were retrieved. Success was defined as a horizontal deviation of up to 15Δ and vertical deviation of <10Δ.

RESULTS

Eleven patients were included. Average patient age at the time of surgery was 4 years. Eight patients with esodeviation up to 70Δ underwent bilateral medial rectus recession; 3 patients with esotropia >70Δ underwent recession plus bilateral Hummelsheim procedure. The mean esodeviation before surgery was 52.5Δ in the first group and 86.6Δ in the second group. The mean horizontal deviation at early follow-up was esotropia of 7.4Δ in the first group and of 15Δ in the second group. The early success rate was 87% in the first group and 67% in the second group. Long-term follow-up revealed exoshift in 43% of the patients in the first group and all 3 patients in the second group.

CONCLUSIONS

In our small patient cohort of patients with Möbius syndrome, bilateral medial rectus recession corrected esodeviations of up to 70Δ. In more severe cases (>70Δ), adding bilateral Hummelsheim procedure was beneficial.

Update on the surgical management of Graves' orbitopathy

Graves' orbitopathy (GO) is a complex autoimmune disorder of the orbit that causes the eye to appear disfigured. GO is typically associated with Graves' disease, an inflammatory autoimmune condition that is caused by thyrotropin receptor autoantibodies. Although our knowledge of the pathophysiology of GO has improved, its exact pathogenesis remains unclear. Some patients suffer from disfigurement, double vision, and even vision loss rather than hyperthyroidism. The disease severity and activity prompt different treatments, as the signs of GO are heterogeneous, so their management can be very complex. Despite medical advances, the first-line treatment for moderate-to-severe active GO is still glucocorticoids, while surgery can be critical for the treatment of chronic inactive GO. Surgery is sometimes required in the acute phase of the disease when there is an immediate risk to vision, such as in dysthyroid optic neuropathy. Most surgeries for GO are rehabilitative and subdivided into three categories: decompression, strabismus repair, and lid surgery. This review is a basic overview of the field, with up-to-date knowledge of the surgical techniques for GO. We review and summarize recent literature on the advances in surgery for GO to provide up-to-date insights on the optimal surgical treatment for GO.

The use of lyophilized bovine pericardium (Tutopatch®) in the management of third nerve palsy following prior conventional strabismus surgery - a case series

To study the secondary management of strabismus due to third nerve palsy using bovine pericardium (Tutopatch®) when previous conventional surgical therapy had failed. Review of our clinic records of selected patients with third nerve palsy, in whom residual deviation had been managed using Tutopatch® after previous surgical correction. The squint angle was measured preoperatively, and at 1 day, 3 months, and if possible 6 months postoperatively. Nine patients were enrolled in this study. One patient had mainly residual vertical deviation and was corrected with tendon elongation of the contralateral superior rectus. Three patients were operated on with tendon elongation of the lateral rectus muscle with or without medial rectus muscle resection and/or advancement (Group 1). Lateral rectus splitting after tendon elongation in addition to the resection and/or advancement of the medial rectus was performed in five patients with complete third nerve palsy (Group 2). In Group 1, the preoperative median squint angle was -20° (range -17° to -25°), which improved postoperatively to -4.5° (range -12° to +3°). In Group 2, the preoperative horizontal and vertical median squint angles were -27° (range -20° to -40°) and 0.5° (range 0° and 20°), respectively. Postoperatively, they had improved to -12.5° (range-2° to -25°), and 1.5° (range 0° to 7°), respectively. Two patients of Group 2 were re-operated due to residual exotropia. No postoperative complications were observed in any patient. In this small series several complex re-do situations of patients with third nerve palsy were evaluated in which Tutopatch® markedly improved outcomes after an initially ineffective surgical management. For better evaluation of its usefulness a study with more patients is recommended.

Congenital Fibrosis of the Extraocular Muscles: An Overview from Genetics to Management

Congenital fibrosis of the extraocular muscles (CFEOM) is a genetic disorder belonging to the congenital cranial dysinnervation disorders and is characterized by nonprogressive restrictive ophthalmoplegia. It is phenotypically and genotypically heterogeneous. At least seven causative genes and one locus are responsible for the five subtypes, named CFEOM-1 to CFEOM-5. This review summarizes the currently available molecular genetic findings and genotype–phenotype correlations, as well as the advances in the management of CFEOM. We propose that the classification of the disorder could be optimized to provide better guidance for clinical interventions. Finally, we discuss the future of genetic-diagnosis-directed studies to better understand such axon guidance disorders.

Elongation of the inferior rectus tendon with fascia lata graft for large vertical squint angles in patients with Graves' orbitopathy

PURPOSE

To investigate the use of fascia lata (FL) grafts for inferior rectus muscle (IRM) tendon elongation in patients with large vertical squint angles with Graves' orbitopathy (GO).

METHODS

In this retrospective study, we included a consecutive series of 20 eyes of 13 patients with GO who underwent IRM tendon elongation with FL. Orthoptic and ophthalmologic examinations including measurement of the head posture, the extent of deviation in primary position (PP), elevation, motility, and binocular diplopia at the tangent of Harms were conducted preoperatively and after a mean postoperative time of 10.8 (5.0-35.0) months in all patients.

RESULTS

The mean total repositioning distance was 9.3 ± 3.6 (3.5-16.0) mm. Postoperatively, we found a significant increase in elevation (5.4 ± 2.4 vs. 2.7 ± 2.4 mm preoperatively, p = 0.011). A significant reduction in vertical squint angle (2.8 ± 3.7 vs. 20.2 ± 18.8 Δ preoperatively, p = 0.004), chin elevation (2.3 ± 3.7 vs. 12.9 ± 6.3° preoperatively, p < 0.001), extorsion in PP (0.1 ± 3.8 vs. 8.4 ± 7.8° preoperatively, p = 0.002), and in elevation (1.8 ± 4.8 vs. 11.1 ± 10.9° preoperatively, p = 0.004) occurred postoperatively. A mean dose-effect relation of 2.6 ± 2.9 Δ/mm was calculated. Postoperatively, the lower eyelid retraction was significantly increased (1.5 ± 1.4 vs. 0.4 ± 0.5 mm preoperatively, p = 0.005).

CONCLUSION

IRM tendon elongation with FL is a feasible and effective procedure without relevant risk for surgery-related complications.

Mapping of bovine pericardium to enable a standardized acquirement of material for medical implants

OBJECTIVES

Bovine pericardium - native, fixed as well as decellularized - is one of the most common implant materials in modern cardiovascular surgery. Although used in everyday procedures, there are no recommendations in regard to which part of the pericardium to prefer. It was the aim of this study, to identify areas of the pericardium with consistent properties and high durability.

METHODS

Fresh bovine pericardia were collected from a local slaughterhouse. The native pericardia were analyzed at 140 spots in regard to thickness and fiber orientation. Based on these results, five promising areas were selected for further evaluation. The pericardia were decellularized with detergents (0.5% sodiumdesoxycholate/0.5% sodiumdodecylsulfate) and subsequently incubated in DNAse. The two investigation groups native und DC consisted of 20 samples each. The efficiency of the decellularization was evaluated by DNA quantification, as well as DAPI and H&E staining. Biomechanical properties were determined using uniaxial tensile tests. To evaluate the microstructure, scanning electron microscopy, Picrosirius Red- and Movat's Pentachrome staining were utilized. To assess the long-term durability, patches were tested in a high-cycle system for a duration equaling the stress of three months in-vivo. Commercially available, fixed pericardium patches served as control group.

RESULTS

Only a limited part of the pericardium showed a homogenous and usable thickness. The decellularization removed all cell nuclei, proven by negative DAPI and H&E staining, and also significantly reduced the DNA amount by 84%. The mechanical testing revealed that two investigated areas had an inconsistent tensile strength. Microscopical observations showed that the integrity of the extracellular matrix did not suffer by the decellularization procedure. During the long-term testing, most of the pericardia slowly lost tautness, though none of them got measurably damaged. Especially one area showed no decline of tensile strength after durability testing at all. Decellularized patches and fixed patches achieved comparable results in mechanical testing and microscopical evaluation after the durability testing.

CONCLUSION

We could clearly document significant, location-based differences within single pericardia. Only one area showed consistent properties and a high durability. We highly recommend taking this into account for future implant material selections.