1. Introduction

According to WHO data, the proportion of congenital clefts of the upper lip and palate (CLP) among congenital malformations averages about 13%. Experts state that on average, one child with cleft lip and palate is born for every 600-1,000 newborns. Currently, there is an increase in the number of patients with this pathology, both as an independent condition and as part of syndromic disorders. It should be noted that this pathology has significant social importance, as CLP substantially affects not only the physical but also the mental development of children. Therefore, timely and correct elimination of the defect plays a key role in the rehabilitation of patients and determines their future quality of life [1,2,3].

Despite the existence of more than 300 methods of surgical treatment for CLP, treating this pathology remains one of the important tasks in pediatric maxillofacial surgery. A.A. Mamedov noted that "most methods are effective when performed by their authors, but do not show good results when performed by other specialists," which is often observed in everyday clinical practice. The relevance of the problem lies not only in the increasing frequency of births of children with CLP and the severity of the defect but also in the complexity of choosing the most suitable and optimal method of surgical treatment.

The application of each methodology depends to some extent on the surgeon/institution, and to date, there is no gold standard for surgical intervention for a specific type of cleft. However, in cases of wide clefts, a single primary closure is often insufficient, considering the increased tension in the defect area and inadequate coverage of the local tissues.

The literature presents some additional methods for primary reconstruction of the palatal cleft, including flaps/grafts from the buccal fat pad (BFP), mucosal/mucosal-muscular flap of the cheek (MCF/MMCF), and acellular dermal matrix (ADM). The aforementioned methods are especially necessary in cases of local tissue volume deficiency to close the defect without tension, which is crucial for preventing the formation of an oronasal fistula and velopharyngeal insufficiency. Many authors confirm that these auxiliary techniques allow for additional tissue coverage in areas of tension and reduce the frequency of postoperative complications. However, to date, there is little data comparing the effectiveness of various auxiliary techniques used in primary repair of palatal clefts.

It should be noted that in cases of large clefts, one primary closure is often insufficient, considering increased tension in the defect area and inadequate coverage of local tissues, especially in the lateral parts of the palate along Ernst-Langenbeck incision lines. This requires the use of various materials or grafts to close the formed lateral defects to reduce tension in the tissues in the surgical intervention area [4,5].

The above-mentioned aspects of cleft surgery necessitate the development of new methods of repair using local tissues and the search for an optimal way to form flaps of sufficient size and good blood supply to prevent necrosis, rejection, and recurrence, as well as primary healing of the lateral parts of the palate with a large tissue volume deficit. Obtaining complete grafts from intraoral donor sites is also a pressing issue.

2. Material and Methods

An analysis of clinical observations was conducted on 103 children aged 1 to 7 years with cleft lip and palate (CLP) and cleft palate (CP) who were under dispensary observation in the pediatric maxillofacial surgery department of the Tashkent State Dental Institute and the Bukhara Regional Multidisciplinary Children's Medical Center from 2022 to 2024. Depending on the severity of the defect, patients were divided into groups according to the classification of Frolova L.E. (1973).

Before the operation, all patients underwent a clinical examination (general clinical blood and urine analysis, biochemical blood analysis for total protein, enzymes, residual nitrogen, urea, bilirubin, electrolytes, and if necessary, chest X-ray, ECG, etc.). In addition, the children were consulted by a pediatrician, anesthesiologist, orthodontist, and, when necessary, an otolaryngologist and neurologist.

To ensure the correct choice of anesthesia method and type of anesthetic, all subjects were examined and consulted by a pediatrician and anesthesiologist before surgical intervention.

The largest number of children - 37 (35.9%) - were operated on using the method of L.E. Frolova. 35 (34%) children were operated on using the method of M.I. Azimov - by transverse incision of the soft palate with longitudinal suturing of the wound. Bardach J. uranoplasty was performed on 31 (30.1%) children.

Depending on the method of covering (material) the wound surface in the area of lateral defects, the subjects were randomly divided into groups:

1st group - iodoform gauze (n=25);

2nd group - PRF (n=27);

3rd group - collagen sponge ("Belkozin," Russia) (n=25);

4th group - buccal fat pad (n=26).

A functional study of the dynamics of blood flow parameters in the mucous membrane of the lateral hard palate defects was carried out using laser Doppler flowmetry (LDF) with the LAKK-M device and software (NPP "Lazma," Moscow, Russia). The perfusion index (PI), average perfusion deviation (σ), and coefficient of variation (Cv) were determined.

The device's operating principle is based on the Doppler effect - the change in signal frequency when radiation (He-Ne low-power laser with a wavelength of 632.8 nm) is reflected from moving objects (erythrocytes) in vessels.

The area of lateral defects was probed with a laser quartz LED tip with a sensor diameter of 3 mm, without mechanical load or pressure on the tissues. The results of signal processing were displayed on the device's indicator panel while simultaneously transmitting values to a personal computer. Parallel recording of blood flow perfusion values was also carried out for subsequent processing and analysis of Doppler waveforms.

Statistical analysis was conducted using OriginPro 8.6 (OriginLab Corporation, USA) with the Two-sample t-Test method. A p-value ≤0.05 was considered statistically significant.

3. Results

Local hemodynamics was assessed using three main parameters that reflect the average values of perfusion changes: mean blood flow (average arithmetic value of the microcirculation index - M), mean perfusion change relative to the average blood flow value (Dx), and coefficient of variation (Kv). For comparative analysis, local hemodynamics was also studied in 20 somatically healthy children without developmental defects or palate defects.

An increase in the dynamic average arithmetic indicator of microcirculation (M) and blood flow modulation (Dx) indicates increased tissue perfusion. However, these changes are not related to a decrease in myogenic tone of metarterioles and precapillary sphincters, but to an increase in blood volume in arterioles and blood stasis in venules, and consequently, to an increase in erythrocyte concentration, as the coefficient of variation decreased (assessment of M and Dx allows exclusion of cardiac and respiratory rhythm effects on the indicator). Thus, a decrease in the Kv indicator reflects deterioration of microcirculation, the degree of which depends on autonomic reactivity.

The initial state of microcirculation in the palatal mucosa was characterized by a decrease in blood flow level (M) by 45.9%, and its intensity (σ) by 38%, indicating relatively satisfactory tissue trophism.

According to LDF data, a week after uranoplasty, changes in tissue blood flow levels of varying degrees were observed. In all groups, an increase in blood flow level (M) by an average of 22% was observed, indicating increased tissue perfusion with blood and associated with traumatic intervention.

The most significant increase in this parameter was noted in group IV (cleft lip and palate) - the values increased by 57.2%. The phenomenon of increased blood flow is associated with surgical trauma and the fact that increased vascular permeability and transudate excretion from capillaries occur, leading to a proliferation phase. Significantly increased tissue perfusion with blood on the 7th day in group IV (cleft lip and palate) indicates that a highly vascularized stroma is forming on the surface of the lateral defect and granulation tissue is growing. During this observation period, an increase in blood flow activity (σ) was also noted in all patients by an average of 45%, and vasomotor activity of microvessels (Kv) increased by an average of 8-9%, which confirms an increase in hyperemia and blood flow intensity in the operated area of the palate.

On the 14th day, indicators in the palatine mucosa showed a stable trend towards improvement in microcirculation parameters. The blood flow level (M) decreased and was lower than the baseline level before uranoplasty by an average of 21.3% in group I, 14.3% in group II, 13.6% in group III, and 7.9% in group IV, while blood flow intensity (σ) increased by an average of 20% in all groups. It should be noted that despite the decrease in blood flow intensity, in group IV, this parameter remained within normal limits, while in the other subjects it did not reach normal values. Vasomotor activity of microvessels (Kv) also increased by an average of 9-11%, which was higher than the values obtained before uranoplasty, associated with active processes of granulation tissue maturation and wound epithelialization. The dynamics of microcirculation parameters indicated an increase not only in blood flow intensity but also in vasomotor activity, which is important for maintaining normal hemodynamic function, as it ensures tissue blood flow modulation and its adaptation to local metabolic needs.

On the 21st day, signs of microcirculation restoration were observed in the palatal mucosa. In group I, the blood flow level (M) increased by an average of 3.6% and approached the initial values (before uranoplasty) against a background of decreased blood flow activity (σ) and vasomotor activity of microvessels (Kv), which together characterized a slight improvement in tissue blood flow in the microcirculatory bed. Conversely, in the remaining study groups, the increase in blood flow level (M) was more significant, indicating a faster rate of restoration of normal blood supply in the intervention area.

Also, in patients of group I, a sharp decrease in blood flow activity (σ) and vasomotor activity of microvessels (Kv) was observed, by 53.3% and 44.8% respectively, which was significantly lower than normal values, indicating congestive phenomena in the soft tissues of the jaws.

On the 28th day after uranoplasty, the trend of improvement in microcirculation indicators generally persisted. In group IV, an increase in blood flow level (M) was observed by an average of 8.2% and this indicator was closest to the lower limit of normal values. In patients of the remaining groups, a different picture was observed - the blood flow level decreased by an average of 5-7%.

Blood vessel activity (σ) decreased by 30.6% in patients of group IV, while in all other groups this indicator increased sharply by an average of 36.4%. It should be noted that despite the observed fluctuations in values, blood vessel activity was within normal values only in representatives of group IV.

Thus, the obtained results indicate a faster restoration of blood flow in the microcirculatory bed of the palatal mucosa in the area of lateral defects in group IV subjects. It should be noted that the indicators characterizing microcirculation were generally within normal values only in patients of this group.

In LDF, such parameters as vascular tone and the integral characteristic of microcirculation efficiency - the fluxmotion index (FMI) - were also studied.

Initial indicators (before uranoplasty) showed that vascular tone was elevated compared to normal, characterizing a state of vasoconstriction. As a result of the deterioration of microcirculation, the integral characteristic of microcirculation efficiency - the fluxmotion index (FMI) - increased by an average of 10%.

Before uranoplasty, a decrease in microcirculation was observed in the palatal mucosa. On the 7th day after the intervention, a reduction in vascular tone was noted. The most significant decrease in this indicator (by 40%) was observed in group I, while in the other groups, vascular tone decreased insignificantly.

At the same time, the fluxmotion index (FMI) in group IV showed a slight tendency to increase (by 4%), which indicated an improvement in microcirculation regulation effectiveness - the development of mild hyperemia and blood flow in response to the surgical intervention. LDF indicators suggested an intensification of compensatory-adaptive mechanisms; pulse fluctuation values were above normal, characterizing impaired venous outflow in the lateral defect area. In groups II and III, the fluxmotion index remained practically unchanged, while in group I, it decreased by an average of 9%.

On the 14th day after uranoplasty, changes in the main amplitude-frequency characteristics were observed, indicating normalization of blood flow in the microcirculatory bed, as well as restoration of normal venous outflow in the venules.

Against the background of normalization of some hemodynamic parameters in the operated area, an increase in microvessel tone was noted in the study groups (by 37.6%, 15.4%, 8.7%, and 9.8%, respectively), which characterized vasoconstriction, limiting blood flow and contributing to a decrease in hyperemia in the microcirculatory bed.

The fluxmotion index (FMI) decreased by 4.3-21% in the groups, indicating strain on the regulatory mechanisms of microcirculation, associated with active processes of granulation tissue maturation.

It should be noted that in patients of group IV, microcirculatory disorders in the palatal mucosa were less pronounced, indicating the absence of tissue tension along the edges of lateral defects. The persisting changes on the 14th day after the intervention are mainly associated with active processes of granulation tissue maturation and epithelialization of the lateral defects.

On the 21st day after uranoplasty, vascular tone in group I increased by 33%, indicating vasoconstriction and limitation of blood flow under conditions of venous congestion in the tissues. In the remaining groups, this parameter decreased by 12%, characterizing the normalization of microvessel tone.

The dynamics of changes in the fluxmotion index (FMI) varied. In group I, the indicator decreased by 30.8%, characterizing tension in microcirculation regulation mechanisms associated with increased venous congestion in the microcirculatory system. In group IV, FMI was within normal values.

On the 28th day after uranoplasty, according to LDF data, the level of rhythmic components stabilized. Vascular tone was restored and exceeded the initial values before uranoplasty. The effectiveness of microcirculation functioning in the palatal mucosa in group I remained reduced, indicating persistent tension in the mechanisms regulating tissue blood flow in the microcirculatory bed. In the remaining study groups, the FMI was close to normal values.

The above values obtained from LDF indicate that in patients of group IV after uranoplasty, minor shifts in the microcirculatory bed are observed, which normalize over a shorter period compared to other study groups.

4. Conclusions

Based on the research results, it has been proven that the overall clinical effectiveness of the algorithm using the buccal fat pad to cover the surface of marginal defects is expressed in accelerating wound epithelialization by 2 times, lengthening the palate to 76.6±0.6 mm, and forming a palatopharyngeal ring with a width of 28.6±0.5 mm.