Cleft lip is one of the most common congenital craniofacial anomalies encountered by plastic and reconstructive surgeons worldwide. It results from the failure of fusion between the medial nasal prominence and the maxillary prominence during embryonic development, leading to varying degrees of disruption in the continuity of the upper lip, alveolus, and occasionally the palate [1]. The condition not only affects facial appearance but also has significant functional consequences involving feeding, speech development, dentofacial growth, and psychosocial well-being [2]. The global incidence of cleft lip with or without cleft palate varies according to ethnicity and geographic region, ranging from approximately 1 in 500 to 1 in 1,000 live births, making it a major public health concern in many countries [3]. Unilateral cleft lip represents the most frequent form of cleft deformity, with a higher prevalence on the left side and among males [4]. The anatomical abnormalities associated with unilateral cleft lip extend beyond a simple discontinuity of the lip tissues. The deformity involves distortion of the orbicularis oris muscle, asymmetry of the Cupid’s bow, shortening of the philtral column, displacement of the alar base, and deficiency of the vermilion on the cleft side [5]. Consequently, successful surgical correction requires restoration of both function and aesthetics while maintaining normal anatomical relationships. The evolution of cleft lip surgery has undergone remarkable development over the past century. Early surgical approaches primarily focused on closure of the defect, whereas modern techniques emphasize precise reconstruction of anatomical landmarks and restoration of muscular continuity [6]. Among the numerous surgical methods described, the rotation–advancement technique introduced by Millard in 1955 remains one of the most widely utilized procedures for unilateral cleft lip repair [7]. The technique preserves the natural Cupid’s bow, allows flexibility in tissue movement, and achieves favorable aesthetic outcomes. However, despite its popularity, several postoperative deformities may still occur, including vermilion notching, inadequate vermilion height, asymmetry of the free vermilion border, and whistle deformity [8]. Vermilion deficiency is considered one of the most noticeable residual deformities following unilateral cleft lip repair. Even when the cutaneous lip and philtral structures are reconstructed satisfactorily, inadequate vermilion fullness may compromise the final cosmetic result and necessitate secondary revision procedures [9]. Several modifications have therefore been proposed to address this issue. One notable advancement was introduced by Onizuka, who developed a vermilion flap technique aimed at augmenting the deficient medial vermilion using tissue harvested from the lateral lip element [10]. This approach seeks to achieve a smooth and symmetrical vermilion border while minimizing the risk of postoperative notching. The Onizuka technique incorporates a small triangular vermilion flap into the modified Millard repair and is particularly useful in patients with unilateral incomplete cleft lip. By redistributing available vermilion tissue and enhancing continuity between the wet and dry mucosal surfaces, the technique attempts to restore a more natural lip contour and improve long-term aesthetic outcomes [11]. Although the procedure has gained acceptance among cleft surgeons, published studies evaluating its effectiveness remain relatively limited, particularly in Middle Eastern populations. Given the importance of achieving optimal vermilion symmetry and minimizing secondary deformities, further evaluation of this technique is warranted. Therefore, the present study was conducted to assess the cosmetic and anthropometric outcomes of the Onizuka modification of the modified Millard technique in patients with unilateral incomplete cleft lip and to compare postoperative measurements with those of healthy age-matched controls.

This prospective case–control study was conducted at the Department of Plastic and Reconstructive Surgery, Azadi Teaching Hospital, Kirkuk, Iraq, between January 2022 and February 2023. The study was designed to evaluate the cosmetic and anthropometric outcomes of unilateral incomplete cleft lip repair using the Onizuka modification of the modified Millard technique. Ethical approval was obtained from the Scientific Council of Plastic and Reconstructive Surgery of the Iraqi Board for Medical Specialties. Written informed consent was obtained from the parents or legal guardians of all participating children prior to enrollment. Study Population A total of 68 participants were included in the study and divided into two groups. The study group (Group A) consisted of 34 children diagnosed with unilateral incomplete cleft lip who underwent primary surgical repair using the modified Millard technique incorporating the Onizuka vermilion reconstruction flap. The control group (Group B) consisted of 34 healthy children without cleft lip who were selected to approximate the age and sex distribution of the study group. Inclusion and Exclusion Criteria Children presenting with unilateral incomplete cleft lip and eligible for primary surgical repair were included in the study. Exclusion criteria comprised complete unilateral cleft lip with or without Simonart’s band, bilateral cleft lip, median cleft lip, syndromic craniofacial anomalies, previous cleft lip surgery, revision cases, and patients with incomplete follow-up records. Preoperative Assessment All patients underwent comprehensive clinical evaluation, including detailed medical history and physical examination. Particular attention was given to the presence of associated congenital anomalies, especially cleft palate and cardiovascular abnormalities. Routine preoperative investigations included complete blood count, coagulation profile, random blood glucose, blood urea, virological screening, chest radiography, and echocardiography when indicated. All patients were evaluated by a pediatric specialist to ensure fitness for surgery. Standardized preoperative photographs were obtained in frontal, lateral, and worm’s-eye views for documentation and subsequent analysis. Surgical Technique All procedures were performed under general anesthesia by the same surgical team. Patients were positioned supine with slight neck extension. Following standard sterile preparation and draping, unilateral incomplete cleft lip repair was performed using the modified Millard rotation–advancement technique. The Onizuka modification involved the design of a small triangular vermilion flap harvested from the lateral lip element. Precise anatomical landmarks were identified, including the crista philtri inferior, Cupid’s bow peaks, white roll, and vermilion–mucosal junction. The triangular vermilion flap was elevated from the lateral segment and inserted into a corresponding incision created at the wet–dry vermilion junction of the medial lip element. This maneuver was intended to compensate for vermilion deficiency, improve continuity of the vermilion border, and minimize the risk of postoperative notching or whistle deformity. Orbicularis oris muscle reconstruction was performed using absorbable sutures to restore muscular continuity. The mucosal and cutaneous layers were subsequently approximated using standard multilayer closure techniques. Special care was taken to achieve accurate alignment of the white roll and Cupid’s bow landmarks. Postoperative Care and Follow-up Postoperative wound care included cleansing with 4% povidone–iodine solution and application of topical antibiotic ointment. Steri-strip dressings were used to support wound healing. Parents received detailed postoperative instructions regarding feeding methods, sleeping position, wound care, and follow-up schedules. All patients were followed for a minimum period of six months after surgery. Clinical assessments were performed during scheduled outpatient visits to evaluate wound healing, scar quality, vermilion symmetry, and potential complications. Outcome Assessment Postoperative outcomes were assessed using standardized frontal digital photographs obtained at least six months after surgery. Anthropometric measurements were performed using Digimizer® software, a validated digital image analysis program widely used in facial anthropometry. The primary outcome measures included: • Vermilion height on cleft and non-cleft sides. • Lateral upper lip vermilion width on cleft and non-cleft sides. • Philtral height on cleft and non-cleft sides. • Cupid’s bow to commissure distance. • Philtral width (peak-to-peak distance). • Commissure-to-commissure mouth width. Secondary outcome measures included postoperative complications, vermilion border continuity, white roll alignment, symmetry of the philtral column, parental satisfaction, and overall cosmetic appearance. Figure 1: lip and vermilion measurements using Digimizer software application for cases Figure 2: Lip and vermilion measurements using Digimizer software application for cases Cosmetic Evaluation Cosmetic outcomes were assessed using standardized postoperative photographs reviewed by the surgical team and parents. Parameters evaluated included symmetry of the Cupid’s bow, philtral column alignment, vermilion border continuity, lateral lip symmetry, white roll matching, and the presence of residual deformities such as muscle bulge, mucosal bulge, vermilion notching, scar contracture, or asymmetry. Statistical Analysis Data were analyzed using Statistical Package for the Social Sciences (SPSS) software version 26.0 (IBM Corp., Armonk, NY, USA). Continuous variables were presented as mean ± standard deviation (SD), whereas categorical variables were expressed as frequencies and percentages. Comparisons between groups were performed using the independent-samples t-test for continuous variables and the Chi-square test for categorical variables. Correlations between anthropometric measurements were evaluated using Pearson’s correlation coefficient. A p-value <0.05 was considered statistically significant. This version is suitable for submission to international plastic surgery, craniofacial surgery, or reconstructive surgery journals.

The study showed that the mean age of children with unilateral incomplete cleft lip was 4.56 ± 1.13 months, while the mean age of the control group was 4.59 ± 1.00 months. No statistically significant difference was observed between the two groups (p = 0.91), indicating successful matching of participants according to age and minimizing the effect of age as a confounding variable. Table 1. Descriptive Statistics of Age Variable Cases (n=34) Controls (n=34) P-value Age (months), Mean ± SD 4.56 ± 1.13 4.59 ± 1.00 0.91 Figure 3 demonstrates the distribution of cleft side among the study population. Left-sided unilateral incomplete cleft lip was observed in 20 patients (58.82%), while right-sided cleft lip was observed in 14 patients (41.18%). Therefore, left-sided clefts represented the majority of cases in the present study. This distribution is in agreement with previously reported epidemiological findings indicating a predominance of left-sided cleft lip deformities. Figure 3: Side distribution across studied cases group Comment on Table 2 The study showed that postoperative vermilion and labial measurements were comparable between patients and controls. Vermilion height on the cleft side was 2.8 ± 0.8 mm compared with 2.5 ± 0.6 mm in controls (p = 0.17). Similarly, vermilion height on the non-cleft side showed no significant difference (p = 0.29). All remaining anthropometric parameters demonstrated p-values greater than 0.05, indicating that the Onizuka modification achieved measurements similar to those observed in healthy children. Table 2. Descriptive Statistics Measurement and Comparison Between Cases and Controls Variable Cases Mean ± SD Controls Mean ± SD P-value Vermilion height (cleft side) 2.8 ± 0.8 2.5 ± 0.6 0.17 Vermilion height (non-cleft side) 2.6 ± 0.9 2.4 ± 0.7 0.29 Lateral upper lip vermilion width (cleft side) 5.9 ± 1.9 5.6 ± 1.8 0.64 Lateral upper lip vermilion width (non-cleft side) 6.8 ± 1.9 6.5 ± 1.9 0.44 Entire mouth width 12.9 ± 2.0 12.8 ± 1.9 0.75 Philtrum width 3.8 ± 0.8 3.6 ± 0.7 0.24 Cupid bow to commissure (cleft side) 3.6 ± 0.5 3.4 ± 0.6 0.19 Cupid bow to commissure (non-cleft side) 3.2 ± 0.5 3.1 ± 0.5 0.47 Philtral height (non-cleft side) 4.9 ± 1.0 4.6 ± 1.0 0.23 Philtral height (cleft side) 4.8 ± 1.1 4.5 ± 1.2 0.31 The study demonstrated a very strong positive correlation between vermilion height on the The study showed a very strong positive correlation between vermilion height on the cleft side and vermilion height on the non-cleft side (r = 0.912, p = 0.001), indicating that patients with greater vermilion height on the cleft side also tended to have greater vermilion height on the non-cleft side. Furthermore, a moderate positive correlation was observed between vermilion height on the cleft side and lateral upper lip vermilion width on the cleft side (r = 0.497, p = 0.003), while a weak positive correlation was found with lateral upper lip vermilion width on the non-cleft side (r = 0.352, p = 0.041). Similarly, vermilion height on the non-cleft side demonstrated a moderate positive correlation with lateral upper lip vermilion width on the cleft side (r = 0.539, p = 0.001). However, no statistically significant correlation was identified between vermilion height on the non-cleft side and lateral upper lip vermilion width on the non-cleft side (r = 0.230, p = 0.192). In addition, a strong positive correlation was observed between lateral upper lip vermilion width on the cleft side and lateral upper lip vermilion width on the non-cleft side (r = 0.726, p = 0.001). These findings indicate that postoperative vermilion dimensions were highly symmetrical and proportionally related between the cleft and non-cleft sides, reflecting the effectiveness of the Onizuka modification in restoring balanced vermilion morphology. Table 3: Correlation Between Vermilion Height on the Cleft Side and Other Vermilion Measurements Among Cases (n = 34) Variables Vermilion Height (Cleft Side) Vermilion Height (Non-Cleft Side) Lateral Upper Lip Vermilion Width (Cleft Side) Lateral Upper Lip Vermilion Width (Non-Cleft Side) Vermilion Height (Cleft Side) — r = 0.912 r = 0.497 r = 0.352 p = 0.001 p = 0.003 p = 0.041 Vermilion Height (Non-Cleft Side) r = 0.912 — r = 0.539 r = 0.230 p = 0.001 p = 0.001 p = 0.192 Lateral Upper Lip Vermilion Width (Cleft Side) r = 0.497 r = 0.539 — r = 0.726 p = 0.003 p = 0.001 p = 0.001 Lateral Upper Lip Vermilion Width (Non-Cleft Side) r = 0.352 r = 0.230 r = 0.726 — p = 0.041 p = 0.192 p = 0.001 Pearson correlation coefficient. The study showed that age was significantly associated with postoperative vertical lip measurements. A significant negative moderate correlation was observed between age and vertical height on the cleft side (r = −0.469, p = 0.005), indicating that increasing age was associated with a reduction in vertical philtral height. However, no significant correlation was found between age and philtral height on the non-cleft side (r = −0.280, p = 0.090). Regarding horizontal lip dimensions, no statistically significant correlations were identified between age and Cupid’s bow to commissure distance on either the cleft side (r = 0.296, p = 0.090) or the non-cleft side (r = 0.310, p = 0.081). Similarly, age was not significantly correlated with philtrum width (r = 0.050, p = 0.779) or entire mouth width (r = 0.004, p = 0.980). These findings suggest that age had a measurable effect on vertical lip height but did not significantly influence horizontal lip dimensions following repair with the Onizuka modification of the modified Millard technique. Table 4: Correlation Between Age and Postoperative Labial Measurements (n = 34) Variable Vertical Height on Cleft Side Philtral Height on Non-Cleft Side Cupid Bow to Commissure (Cleft Side) Cupid Bow to Commissure (Non-Cleft Side) Philtrum Width (Peak-to-Peak) Entire Mouth Width Age r-value -0.469 -0.280 0.296 0.310 0.050 0.004 P-value 0.005 0.090 0.090 0.081 0.779 0.980 N 34 34 34 34 34 34 Pearson correlation coefficient. The study showed that age was significantly associated with postoperative vermilion height measurements. A significant negative moderate correlation was observed between age and vermilion height on the cleft side (r = −0.443, p = 0.009), indicating that increasing age was associated with a decrease in vermilion height. Similarly, a significant negative moderate correlation was identified between age and vermilion height on the non-cleft side (r = −0.512, p = 0.002). In contrast, no statistically significant correlations were observed between age and lateral upper lip vermilion width on either the cleft side (r = 0.082, p = 0.646) or the non-cleft side (r = 0.096, p = 0.591). These findings indicate that while vermilion height tended to decrease with increasing age, vermilion width remained relatively stable and unaffected by age. Overall, the results suggest that age had a significant influence on vertical vermilion dimensions but did not affect horizontal vermilion width measurements following repair with the Onizuka modification of the modified Millard technique. Table 5: Correlation Between Age and Vermilion Measurements (n = 34) Variable Vermilion Height on Cleft Side Vermilion Height on Non-Cleft Side Lateral Upper Lip Vermilion Width (Cleft Side) Lateral Upper Lip Vermilion Width (Non-Cleft Side) Age r-value -0.443 -0.512 0.082 0.096 P-value 0.009 0.002 0.646 0.591 N 34 34 34 34 The study compared postoperative anthropometric measurements according to the affected side of the cleft lip. The results demonstrated that vermilion height on the cleft side was significantly greater among patients with left-sided clefts compared with those with right-sided clefts (2.7 ± 0.6 mm vs. 2.3 ± 0.6 mm, p = 0.04). Similarly, vertical philtral height on the cleft side was significantly higher in left-sided clefts (4.9 ± 1.2 mm vs. 4.0 ± 0.9 mm, p = 0.01). In contrast, no statistically significant differences were observed between left- and right-sided clefts regarding vermilion height on the non-cleft side (p = 0.13), lateral upper lip vermilion width on the cleft side (p = 0.62), lateral upper lip vermilion width on the non-cleft side (p = 0.21), entire mouth width (p = 0.41), philtrum width (p = 0.52), Cupid’s bow to commissure distance on the cleft side (p = 0.50) or non-cleft side (p = 0.66), and philtral height on the non-cleft side (p = 0.50). These findings indicate that most postoperative lip dimensions were comparable between left- and right-sided clefts. However, patients with left-sided clefts demonstrated significantly greater vermilion height and vertical philtral height on the cleft side, suggesting a modest influence of cleft laterality on these specific measurements. Table 6: Descriptive Statistics Measurement and Comparison Between Left- and Right-Sided Clefts Among Cases (n = 34) Variable Left Side Mean SD Right Side Mean SD P-value Vermilion height (from peak of Cupid’s bow to free edge vermilion) on cleft side 2.7 0.6 2.3 0.6 0.04 Vermilion height on non-cleft side 2.6 0.7 2.2 0.6 0.13 Lateral upper lip vermilion width on cleft side 5.8 1.9 5.5 1.6 0.62 Lateral upper lip vermilion width on non-cleft side 6.8 1.8 6.0 2.0 0.21 Entire mouth commissure-to-commissure width 13.0 2.0 12.4 1.8 0.41 Philtrum width (peak-to-peak) 3.6 0.7 3.7 0.7 0.52 Cupid’s bow to commissure – cleft side 3.5 0.6 3.4 0.6 0.50 Cupid’s bow to commissure – non-cleft side 3.2 0.5 3.1 0.5 0.66 Philtral height on non-cleft side 4.7 1.2 4.4 0.9 0.50 Vertical height on cleft side 4.9 1.2 4.0 0.9 0.01 Independent-samples t-test. The study demonstrated excellent postoperative cosmetic outcomes. Symmetry and smoothness of the free vermilion border were achieved in 97% of patients, while accurate white roll alignment was observed in 97% and philtral column symmetry in 91.1% of patients. Table 7: Validation of Unilateral Cleft Lip Surgical Outcomes Evaluation Scale Parameter No. % Symmetry of philtral column 31 91.1 Precise white roll alignment 33 97.0 Symmetry of commissure distance 32 94.2 Symmetry of lip fullness 31 91.1 Smooth vermilion border 33 97.0 The study showed a very low postoperative complication rate. Incorrect Cupid's bow peak position, discontinuity of the vermilion border, imperfect alignment, and muscle bulge were each observed in only one patient (2.9%), while no scar contracture or mucosal bulge was reported. Table 8. Postoperative Cosmetic Results Complication No. % Scar contracture 0 0 Incorrect peak position 1 2.9 Vermilion border discontinuity 1 2.9 Imperfect alignment 1 2.9 Muscle bulge 1 2.9 Mucosal bulge 0 0 The study demonstrated a remarkably high level of parental satisfaction following surgery. A total of 94.2% of parents reported being happy with the surgical outcome, while the remaining 5.8% reported being satisfied. No parent expressed dissatisfaction. Table 9. Parents' Satisfaction Score Satisfaction Level No. % Happy 32 94.2 Satisfied 2 5.8 Unsatisfied 0 0 Figure 4: A four months child with right sided incomplete cleft lip , A : preoperative photos in 5 frontal , basal ,worm′s eye view , from right to left respectively , B: photos of vermilion flap 6 elevation , C: results immediate postoperatively in frontal , basal , worm′s eye view ( from right to 7 left) respectively , D : 6 monthes postoperatively in frontal , basal , worm′s eye view ( from right 8 to left ) respectively . Figure 5: A three months old male with right sided incomplete CL , A : preoperative view (on 4 frontal , basal, worm′s eye view , respectively from right to left) , B: the results in operation room 5 (on frontal , basal, worm′s eye view , respectively from right to left) , C : 6 months post 6 operatively ( in frontal , basal and worm′s eye view , from right to left , respectively ) .

The primary objective of cleft lip repair is not only to achieve closure of the defect but also to restore normal anatomy, function, and facial aesthetics. In unilateral incomplete cleft lip, particular attention must be directed toward reconstruction of the vermilion, Cupid’s bow, philtral column, and orbicularis oris muscle to obtain optimal long-term cosmetic outcomes [1,2]. The present study evaluated the effectiveness of the Onizuka modification of the modified Millard technique in patients with unilateral incomplete cleft lip and demonstrated favorable anthropometric and cosmetic outcomes with a low complication rate and high parental satisfaction. The mean age of patients at the time of surgery was 4.56 ± 1.13 months, which is consistent with the widely accepted timing of cleft lip repair based on the “Rule of 10s” proposed by Millard and supported by contemporary cleft surgery guidelines [3,4]. Early surgical intervention during the first six months of life has been associated with improved tissue healing, favorable scar maturation, and enhanced psychosocial outcomes for both patients and families [5,6]. Similar age distributions have been reported by El-Sayed et al. [7], Murthy et al. [8], and Adetayo et al. [9], who found that most unilateral cleft lip repairs were performed between 3 and 6 months of age. In the present study, left-sided cleft lip represented 58.8% of cases, whereas right-sided clefts accounted for 41.2%. This finding agrees with numerous epidemiological studies reporting a predominance of left-sided unilateral cleft lip deformities [10,11]. Mossey et al. [12] and Dixon et al. [13] reported that approximately two-thirds of unilateral cleft lips occur on the left side. The exact mechanism remains unclear; however, asymmetrical embryological development and vascular factors have been proposed as potential explanations [14]. One of the most important findings of this study was the absence of significant differences between postoperative anthropometric measurements in repaired patients and those of healthy controls. Vermilion height, philtral height, vermilion width, and other lip dimensions were statistically comparable between groups (all p > 0.05). These findings suggest that the Onizuka modification effectively restores normal lip proportions and achieves near-symmetrical reconstruction. Similar outcomes have been reported by He et al. [15], who demonstrated that modified Millard repair combined with vermilion reconstruction could produce measurements approaching those observed in non-cleft individuals. Vermilion deficiency remains one of the most challenging aspects of unilateral cleft lip repair. Inadequate vermilion fullness frequently results in vermilion notching, whistle deformity, and asymmetry that may necessitate secondary revision procedures [16]. Onizuka introduced the triangular vermilion flap specifically to address this problem by transferring tissue from the lateral lip element to the deficient medial segment [17]. The current findings support the effectiveness of this approach, as postoperative vermilion measurements showed excellent symmetry and strong correlations between the cleft and non-cleft sides. The correlation analysis demonstrated a very strong positive association between vermilion height on the cleft side and vermilion height on the non-cleft side (r = 0.912, p = 0.001). This result indicates a high degree of bilateral symmetry following repair. Moreover, significant correlations between vermilion height and vermilion width suggest that restoration of one vermilion dimension contributes positively to overall lip harmony. Similar observations have been reported by Noordhoff [18], Fisher [19], and Mulliken [20], who emphasized that vermilion symmetry is among the most critical determinants of aesthetic success after cleft lip surgery. An interesting finding in this study was the negative correlation between age and both vermilion height and philtral height. Although the correlation was moderate, it suggests that postoperative growth may influence vertical lip dimensions over time. Previous longitudinal investigations by Kluba et al. [21] and Amaratunga [22] also demonstrated changes in vermilion height during facial growth and development. These findings highlight the importance of long-term follow-up in cleft lip patients to assess growth-related changes and determine whether secondary procedures become necessary. The comparison according to cleft side revealed significantly greater vermilion height and vertical philtral height among patients with left-sided clefts. Although the clinical significance of this observation remains uncertain, similar asymmetries have been reported by Chong et al. [23], who noted differences in tissue hypoplasia between left- and right-sided clefts. The authors suggested that embryological variations and differential tissue deficiency may contribute to these findings. Nevertheless, most other anthropometric measurements were comparable between sides, indicating that laterality had limited influence on overall surgical outcomes. The cosmetic assessment performed in this study demonstrated highly favorable results. Symmetry and smoothness of the vermilion border were achieved in 97% of patients, while precise white-roll alignment was obtained in 97% and philtral symmetry in more than 90% of cases. These outcomes compare favorably with previous reports evaluating other techniques. El-Sayed et al. [7] reported good-to-excellent vermilion border outcomes in approximately 76% of patients using the white-roll vermilion flap technique, whereas Noordhoff [18] reported satisfactory vermilion reconstruction in most cases but with occasional residual asymmetry. Accurate reconstruction of the white roll is widely recognized as a key determinant of successful cleft lip repair [24]. Even minimal discrepancies may be readily noticeable because of the prominent visual contrast between skin and vermilion. In the present study, only one patient demonstrated imperfect white-roll alignment, indicating excellent technical reproducibility of the procedure. Similar observations have been reported by Fisher [19], Cutting [25], and Mulliken [20], who emphasized meticulous alignment of anatomical landmarks during primary repair. The postoperative complication rate in this study was remarkably low. Only one patient developed muscle bulge, one exhibited vermilion discontinuity, and one demonstrated an incorrect Cupid’s bow peak position. No cases of scar contracture or mucosal bulging were observed. These findings compare favorably with those reported by Soltani et al. [26], who observed hypertrophic scarring in approximately 25% of patients, and Adesina et al. [27], who reported vermilion notching in nearly one-third of repaired cleft lips. The low complication rate observed in the present study may reflect meticulous surgical technique, careful tissue handling, and precise muscle reconstruction. Proper restoration of the orbicularis oris muscle is crucial for both aesthetic and functional outcomes [28]. Failure to achieve adequate muscle continuity may result in lip asymmetry, impaired animation, and secondary deformities. The low incidence of muscle-related complications in the current study supports the effectiveness of the Onizuka modification in facilitating satisfactory muscular reconstruction. Parental satisfaction represents an important indicator of surgical success. In the present study, 94.2% of parents reported being happy with the surgical outcome, while the remaining 5.8% reported satisfaction. No parent expressed dissatisfaction. Similar levels of parental satisfaction have been reported by Kirschner et al. [29], El-Sayed et al. [7], and Mishra et al. [30]. High parental satisfaction likely reflects the favorable cosmetic outcomes, low complication rates, and improved facial symmetry achieved through the procedure. Several limitations should be considered when interpreting the findings of this study. First, the sample size was relatively small and included only patients with unilateral incomplete cleft lip. Second, the follow-up period was limited to six months, which may not fully capture long-term growth-related changes. Third, the study relied primarily on two-dimensional photographic analysis rather than three-dimensional imaging systems. Future studies involving larger multicenter cohorts, extended follow-up periods, and advanced three-dimensional anthropometric assessments are recommended. Overall, the findings of the present study demonstrate that the Onizuka modification of the modified Millard technique provides excellent aesthetic and anthropometric outcomes in unilateral incomplete cleft lip repair. The technique effectively restores vermilion symmetry, achieves favorable lip proportions comparable to those of healthy children, minimizes postoperative deformities, and results in high parental satisfaction. These findings support its continued use as a reliable and effective approach for primary repair of unilateral incomplete cleft lip.

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