Dynamic viscosity of the wall of the lacrimal sac in disorders of the patency of the lacrimal ducts.

PURPOSE: To assess the dynamic viscosity of the lacrimal sac wall in patients with various origins of lacrimal duct obstruction. METHODS: The study was performed in 35 cases: 21 cases with primary nasolacrimal duct obstruction (PANDO) and 14 cases with secondary nasolacrimal duct obstruction after radioiodine therapy (SALDO). The study of biomechanical properties of the lacrimal sac was carried out using a test bench. The principle of the study was to indent the sample at a given speed and record the data obtained from the sensor of the force transmitted to the sample. The area under the curve (AUC) and the peak viscosity were calculated. A qualitative characteristic of the obtained curve was given. RESULTS: Median AUC in patients with PANDO was 17 × 106 [6 × 106; 19 × 106] N/m2 × s, in patients with SALDO 21 × 106 [13 × 106; 25 × 106] N/m2 × s. Intergroup differences were statistically significant (p = 0,048). The median peak viscosity in PANDO patients was 29 × 106 [25 × 106; 35 × 106] N/m2, in patients with SALDO 32 × 106 [21 × 106; 41 × 106] N/m2. The qualitative characteristics of the obtained curves differed. CONCLUSION: Biomechanical properties of the lacrimal sac may vary depending on the cause of obliteration of the lacrimal ducts. The integrated dynamic viscosity is significantly higher in SALDO patients due to exposure to radioiodine compared to that in PANDO patients.

[Anatomical structure and morphometric parameters of the distal segment of the lacrimal drainage system]. / Anatomicheskoe stroenie i morfometricheskie pokazateli vertikal'nogo otdela slezootvodyashchikh putei.

The article analyzes the literature data concerning the anatomical structure of the tear ducts with a focus on morphometric studies of individual structures. It is noted that, despite the high information content of cadaveric studies, most of the information to date has been obtained with the use of intravital radiation visualization methods. It is shown that the lacrimal drainage system has age, gender, and racial characteristics. Most studies focus on features of the bone nasolacrimal canal, while there is a relative shortage of research devoted to soft-tissue nasolacrimal duct. The analysis showed that most of the studies are devoted to particular morphometric indicators, which makes it difficult to obtain a complete objective picture of the size of the tear duct. Information about its volume can be found only in a couple of studies. The numerical values of the obtained data vary, which can be explained by a different approach to the selection of research subjects, sample sizes, anatomical criteria and the calculation method of morphometric parameters. There are only a few studies on morphometric parameters of the nasolacrimal duct in healthy humans, which is extremely important for determining the pathogenesis of disorders of the patency of the lacrimal drainage system.

[Dacryocystorhinostomy with a counteropening in the treatment of secondary nasolacrimal duct obstruction after radioiodine therapy]. / Dakriotsistorinostomiya s nalozheniem kontrapertury pri vtorichnoi obliteratsii slezootvodyashchikh putei vsledstvie terapii radioaktivnym iodom.

Among secondary forms of nasolacrimal duct obstruction caused by radioactive iodine therapy, its distal forms localized in the area of the Hasner's valve are predominant. In this regard, during dacryocystorhinostomy (DCR) there is a high probability of developing the sump syndrome, for which the anatomical prerequisite is that the lower edge of the DCR ostium is above the level of obstruction. In such cases, we propose to supplement DCR with a counteropening in the area of the Hasner's valve. PURPOSE: This study analyzes the clinical effectiveness of dacryocystorinostomy with a counteropening. MATERIAL AND METHODS: The outcomes of 49 surgeries (49 patients) with secondary acquired nasolacrimal duct obstruction due to radioactive iodine therapy were analyzed, including 34 DCR and 15 DCR with a counteropening. The clinical outcomes were analyzed over the longest possible period after surgery. The analysis included the severity of tearing on the Munk scale, the characteristic of the formed ostium on the M. Ali scale and the height of the tear meniscus. Differences were considered significant at a confidence level of 95% (p≤0.05). RESULTS: Analysis of the results of the performed surgeries showed that DCR was clinically effective in 30 (88%) cases, DCR with a counteropening - in 15 (100%) cases. The differences were not statistically significant in the total sample, but were statistically significant when comparing the results of surgeries in patients with distal obliteration. CONCLUSION: The developed and clinically tested method of DCR with a counteropening in the area of the Hasner's valve was completely effective in 15 patients with secondary nasolacrimal duct obstruction caused by radioiodine therapy.

[The lacrimal apparatus as an organ at risk during radionuclide therapy].

Within the framework of the article, the authors analyzed the available information about the damage to the lacrimal apparatus during radionuclide therapy. In focus of article lesions of the lacrimal production system, the main and accessory lacrimal glands, as well as lacrimal drainage are considered. It was found that damage to the lacrimal apparatus is characteristic of 131I therapy for thyroid cancer, as well as for radioligand therapy using anti-PSMA antibodies labeled with 177Lu and 225Ac. 177Lu-PSMA and 225Ac-PSMA may damage the lacrimal gland with the formation of a clinically pronounced "dry eye syndrome". The pathogenesis of such lesions is associated with the accumulation of a radioisotope in the tissues of the lacrimal apparatus, while during therapy with 131I, accumulation is realized due to the expression of the sodium-iodine symporter in the nasolacrimal duct, and during therapy with 177Lu-PSMA and 225Ac-PSMA, the radiobiological effect is realized in connection with the expression PSMA by lacrimal tissue. An analysis of the available sources showed that to date there are no results of systematic studies on the problem, there is a lack of knowledge regarding the individual risks of developing these complications, methods for their prevention that have proven effectiveness have not been developed, and the treatment methods used, having relatively low efficiency, are not specialized. The authors concluded that the strengthening of interdisciplinary interaction, as well as the organization verification methodology and correct studies, can contribute to solving problems related to the study of the complications under consideration.