Ultrasound evaluation of the anatomy and hemodynamics of the Giacomini vein

Introduction

The small saphenous vein (SSV) is an important component of the superficial venous system of the lower extremities and typically drains into the popliteal vein (1). In the mid-19th century, the Italian anatomist Carlo Giacomini first reported that approximately 94% of SSVs do not terminate solely in the popliteal vein. This figure represents the total incidence of any SSV thigh extension; the incidence of the classic Giacomini vein (GV) with great saphenous vein (GSV) confluence was approximately 86.3% based on the same dataset. Instead, they extend proximally along the posterior thigh and ultimately drain into the GSV or the deep venous system (e.g., the femoral vein), with only a small proportion ending in muscular or other surrounding tissues (2). This proximal extension is termed the GV. According to the 2002 International Interdisciplinary Consensus on Venous Anatomical Terminology, the GV is a common subtype of the thigh extension of the SSV (3). As an integral component of the lower limb venous network, the GV may also develop reflux and varicosities under conditions of venous hypertension in the lower extremities (4). Accurate preoperative identification, comprehensive hemodynamic evaluation and reasonable interpretation of blood flow behavior of the GV are essential to formulate targeted treatment plans, reduce intraoperative injury and lower the recurrence rate of lower extremity varicose veins (5). Prior studies have not comprehensively examined differences in GV detection rates according to sex or limb laterality. Additionally, limited evidence is available regarding the association between the severity of saphenous vein reflux and GV-related parameters. Published studies from China addressing the GV remain limited, and large-scale, in-depth analyses are lacking. Ultrasound is currently the preferred modality for evaluating lower extremity veins; however, standardized criteria for GV ultrasound assessment were previously unavailable (6,7).

Based on a review of the literature, a standardized protocol for GV ultrasound examination was established. The distribution characteristics of the GV among individuals were examined, and the effects of different clinical classifications of varicose veins, types of saphenous vein reflux, and degrees of reflux severity on the anatomical and hemodynamic characteristics of the GV were analyzed. The objective was to provide additional reference data on the ultrasound imaging characteristics of the GV in the Chinese population, and to offer more accurate and valuable evidence for the ultrasound diagnosis and differential diagnosis of chronic venous insufficiency of the lower extremities, varicose veins, and other related diseases. We present this article in accordance with the STROBE reporting checklist (available at https://qims.amegroups.com/article/view/10.21037/qims-2026-0526/rc).

Methods

Participants

A total of 238 limbs from 121 patients (including 4 patients with unilateral limb involvement) who were both outpatient and inpatient at Aerospace Center Hospital during the period from July 2025 to January 2026 were prospectively continuously included. All limbs were clinically staged according to the Clinical (C) component of the CEAP (Clinical, Etiological, Anatomical, and Pathophysiological) classification system (2020 revision) (8). Limbs classified as C0–C4 were included, with C0 designated as the primary group and C1–C4 designated as the varicose group. C0 patients, although lacking visible varicose veins, were included if they presented with persistent lower limb symptoms (e.g., heaviness, pain, swelling) suggestive of chronic venous disease, or underwent vascular screening for other indications. C1 patients were included in the varicose group because they often present with symptoms and may exhibit early venous reflux, placing them on the same pathophysiological spectrum as C2–C4 patients. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Ethics Committee of Aerospace Center Hospital (No. 2025-022). Written informed consent was obtained from all participants.

Inclusion criteria: (I) age 18–75 years; (II) limbs classified as C0–C4 according to the CEAP; and (III) ability to cooperate fully with ultrasound and digital subtraction angiography (DSA) examinations.

Exclusion criteria: (I) Limbs classified as C5 or C6 according to the CEAP; (II) ultrasound evidence of deep venous valve insufficiency (reflux time >1 s); (III) limbs with a current or prior history of lower extremity venous thrombosis; (IV) history of lower extremity arterial or venous surgery; (V) limbs with congenital venous malformations, arteriovenous fistulas, or severe lymphedema; (VI) patients with severe cardiac, pulmonary, hepatic, or renal insufficiency, advanced malignancy, pregnancy, lactation, or known coagulation disorders; (VII) cases in which clear imaging could not be obtained due to obesity, edema, or other factors; (VIII) truncal diameter of the SSV <2 mm (due to unreliable ultrasound visualization and measurement of the GV in such cases).

Among the 121 enrolled participants, 38 underwent both ultrasound and DSA examinations within 2 weeks for combined assessment of GV classification. The physicians performing ultrasound and DSA were blinded to each other’s imaging data and diagnostic results. The remaining 83 patients underwent ultrasound examinations only. GV detection rate, classification, diameter, reflux detection, and reflux duration in all 121 patients were assessed exclusively based on ultrasound findings.

Methods

Instruments

A VINNO G86E color Doppler ultrasound system (VINNO Technology Co., Ltd., Suzhou, China) equipped with a U5–15L linear array probe and a Mindray UTM-400 color Doppler ultrasound system (Shenzhen Mindray Co., Ltd., Shenzhen, China) equipped with an L12–3 probe were used. Examination parameters for venous assessment were optimized accordingly.

Ultrasound examination protocol

• All examinations were conducted with patients in the standing position, with the examined limb maintained in a non-weight-bearing state. Two-dimensional ultrasound was initially used to assess venous patency of the lower extremities and to identify thrombus formation. Color Doppler ultrasound was subsequently used to assess reflux in the GSV and SSV, and reflux duration was recorded.
• The standardized ultrasound protocol for the GV was based on the 2022 Clinical Practice Guidelines for the Management of Varicose Veins of the Lower Extremities issued by the Society for Vascular Surgery, American Venous Forum, and American Vein and Lymphatic Society, and was summarized as follows (6): (i) patients were examined with the affected limb unweighted. During the examination, the probe was moved slowly while gentle pressure was applied to the skin. (ii) On two-dimensional ultrasound, scanning was initiated at the terminal segment of the SSV. During the examination, the probe was moved slowly with gentle compression applied to the skin. If the SSV was observed to ascend proximally after passing through the popliteal fossa—regardless of whether its main trunk drained into the popliteal vein—GV was confirmed. Subsequently, combined longitudinal and transverse scans were performed to identify its course and point of confluence. (iii) Measurement of the GV diameter: the anteroposterior diameter between the intimal layers was measured in a relatively straight segment (transverse section) approximately 2–4 cm above the popliteal crease. Three measurements were obtained, and the mean value was calculated, as depicted in Figure 1. (iv) Assessment of GV reflux: under color Doppler mode, the longitudinal section of the vessel is clearly visualized with the beam-vessel angle kept less than 60°. Squeezing maneuver was applied and then rapidly released, and retrograde blood flow signals within the lumen were visually observed to preliminarily determine the presence of reflux. After reflux is confirmed, the sample volume is placed at the center of the vascular lumen under pulsed wave Doppler mode with appropriate adjustment of sampling gate size, and the duration of retrograde blood flow spectrum is recorded simultaneously.
  

  Figure 1 Standard transverse section for measurement of the internal diameter of the GV. GV, Giacomini vein.

In this study, based on the international interdisciplinary consensus on venous anatomical terminology, the GV was defined as the proximal thigh extension of the SSV that could be continuously traced along a well-defined trunk on ultrasound; isolated high terminal variations with a thin, branching course and no communication with the GSV were excluded.

Diagnostic criteria

• Classification of saphenous vein reflux was based on the Chinese Guidelines for Diagnosis and Treatment of Chronic Venous Diseases, as follows: 0.5–1.0 s, reflux present; ≥1.0 to <2.0 s, mild reflux; ≥2.0 to <3.0 s, moderate reflux; ≥3.0 s, severe reflux (9). A GV reflux duration ≥0.5 s was defined as reflux.
• From Giacomini’s classical anatomical description and subsequent clinical studies, the course of the GV was classified into four types (10): (i) GSV confluence type: the GV originated proximally from the SSV, penetrated the deep fascia, ascended superficially along the posterior thigh within the subcutaneous tissue, and converged anteriorly and medially into the GSV. (ii) Deep vein confluence type: the main trunk of the GV penetrated the deep fascia in the thigh during its ascending course and extended toward the deep femoral vein. (iii) Complex confluence type: the main trunk of the GV ascended and ultimately converged into multiple veins through several branches. (iv) Other confluence type: the GV did not converge into the GSV or femoral vein but instead terminated as small branches within the subcutaneous tissue of the posterior thigh, nerve-associated venous plexuses, or muscle tissue, with specific termination sites not clearly identifiable on ultrasound (Figure 2).
  

  Figure 2 GV types according to Giacomini’s classical anatomical description. (A) Type A GV, GSV confluence type. (B) Type B GV, deep vein confluence type. (C) Type C GV, complex confluence type. (D) Type D GV, other confluence type. (E) GV not detected. GSV, great saphenous vein; GV, Giacomini vein.

Statistical analysis

Statistical analyses were performed using SPSS 26.0. Normality was assessed using the Shapiro-Wilk test. For measurement data with a normal distribution, results were expressed as the mean ± standard deviation. Comparisons between two groups were conducted using the independent samples t-test, and comparisons among multiple groups were performed using one-way analysis of variance. For measurement data not following a normal distribution, results were expressed as the median [25^th percentile (P₂₅), 75^th percentile (P₇₅)]. Comparisons between two groups were conducted using the Wilcoxon rank-sum test, and comparisons among multiple groups were conducted using the Kruskal-Wallis test. Categorical data were presented as numbers and percentages. Group comparisons were conducted using the Chi-squared test or Fisher’s exact test, as appropriate. P<0.05 was considered statistically significant. For multiple comparisons, P values were adjusted using the Bonferroni correction method.

Results

Patient demographics

A total of 121 patients were included in the analysis consisting of 50 male patients (41.32%) and 71 female patients (58.68%), aged 18–75 years, with a mean body mass index (BMI) of 22.91±2.93 kg/m². Among these, 38 patients (76 limbs) underwent both color Doppler ultrasound and DSA examinations, whereas 83 patients (162 limbs) underwent color Doppler ultrasound only. No statistically significant differences in sex distribution, age, or BMI were observed between the two groups (P>0.05).

Consistency check of ultrasound and DSA in 76 limbs

Both modalities detected 60 cases of GV, demonstrating complete agreement. A high level of concordance was observed in GV classification, with a kappa value of 0.854 [95% confidence interval (CI): 0.752, 0.956], as presented in Table 1 and Figures 3,4.

Figure 3 GV confluence into the GSV in the right lower limb (type A). (A) Ultrasound demonstrated the GV running superficially within the subcutaneous tissue before converging into the GSV. (B) DSA demonstrated the GV converging into the GSV in the upper medial thigh. Long arrow: GV; short arrow: GSV. DSA, digital subtraction angiography; GSV, great saphenous vein; GV, Giacomini vein.

Figure 4 GV confluence into the femoral vein in the right lower limb (type B). (A) Ultrasound demonstrated the SSV converging into the popliteal vein at the popliteal fossa and continuing proximally. (B) The GV was observed to continue ascending toward the femoral vein. (C) Transverse section showing the GV located deep to the muscle layer. (D) DSA demonstrated the GV ultimately converging into the femoral vein. Thin arrow: GV; thick arrow: confluence point of the GV and femoral vein. DSA, digital subtraction angiography; GV, Giacomini vein; POPV, popliteal vein; SSV, small saphenous vein.

Distribution of GV

Among the 121 patients, 117 (96.69%) presented with bilateral limb involvement, whereas 4 (3.31%) had unilateral involvement. The GV was detected in 176 limbs (73.95%), with the GSV confluence type accounting for the highest proportion. The detection rate was significantly higher in the right lower limb than in the left (P<0.05). No statistically significant difference in GV detection rate was observed between sexes (P>0.05), as depicted in Table 2 and Figure 5.

Figure 5 Distribution of GV types among 176 cases (GSV confluence type; deep vein confluence type; complex confluence type; other confluence type). GSV, great saphenous vein; GV, Giacomini vein.

Comparison of GV parameters across different CEAP levels

As presented in Tables 3,4, 116 limbs were classified as C0 and 122 limbs as C1–C4. The detection rates of the GV and GV reflux were significantly higher in the varicose group than in the primary group. Although the detection rate of GV reflux showed a gradual increase with higher CEAP classifications, no statistically significant differences were observed in GV incidence, inner diameter, reflux detection rate, or reflux duration among the different classifications within the varicose group (P>0.05), as presented in Tables 3,4 and Figure 6.

Figure 6 Spectral Doppler waveform demonstrating reflux following squeezing maneuver in the GV. After compressing the distal limb and releasing quickly, the spectral Doppler showed a reverse blood flow spectrum within the GV lumen, with a duration of more than 0.5 seconds. GV, Giacomini vein.

Comparison of GV parameters among different reflux types

As depicted in Table 5, statistically significant differences in GV inner diameter were observed among different types of saphenous vein reflux (P<0.05). However, subsequent multiple comparisons demonstrated no significant differences in GV inner diameter between any two reflux types (P>0.05). Significant differences were identified in the detection rate of GV reflux among the different reflux types (P<0.05). Further multiple comparisons indicated that the incidence of GV reflux was significantly higher in the SSV reflux group and in the combined reflux group than in the GSV reflux group (P<0.05). Multiple comparisons further demonstrated that the incidence of GV reflux was significantly higher in the SSV reflux group and in the combined reflux group than in the GSV reflux group (P<0.05). As presented in Table 6, no statistically significant differences were observed in GV inner diameter or GV reflux duration among groups stratified by GSV reflux severity (P>0.05). Although the GV reflux detection rate showed a progressive increase with greater GSV reflux severity, this trend did not reach statistical significance (P>0.05). No statistically significant differences were identified in GV inner diameter, GV reflux detection rate, or GV reflux duration among groups with varying severities of SSV reflux (P>0.05).

Discussion

The GV represents the principal pathway by which the SSV extends into the thigh and serves as an important connecting channel within the superficial venous system of the lower extremities. The detailed anatomical and ultrasonographic characteristics of the GV have been well documented in previous authoritative consensus documents (11,12). In brief, the GV runs within the fascial space deep to the superficial fascia. This triangular space is medially adjacent to the semitendinosus muscle and laterally to the long head of the biceps femoris muscle. Under pathological conditions, the GV may function either as a passive pathway for saphenous vein reflux or as a compensatory escape pathway. It may develop varicosities secondary to valvular insufficiency. A relatively rare and specific type of paradoxical reflux may also occur in the GV. When the saphenopopliteal junction is incompetent, blood from the popliteal vein refluxes into the SSV, increasing distal pressure and forcing blood upward through the GV into the GSV, forming a retrograde flow against gravity. This is a unique hemodynamic phenomenon closely related to its distinctive anatomical structure (13). Although not the focus of this study, identification of paradoxical reflux is also of clinical significance for treatment selection and recurrence risk assessment.

Varicose veins not originating from the main truncal veins may be readily overlooked on ultrasound examination and consequently under-recognized in clinical practice. Therefore, accurate preoperative assessment of the anatomical course and hemodynamic characteristics of the GV, using modalities such as color Doppler ultrasound, is essential for the development of comprehensive and precise treatment strategies and for the prevention of postoperative recurrence.

Color Doppler ultrasound was used as the primary investigative method in this study. Standardized measurements of the GV were performed in 238 limbs, and the anatomical and hemodynamic characteristics of the GV were analyzed in detail. The overall detection rate of the GV was high, with significantly higher detection in the right lower limbs compared with the left lower limbs, and no statistically significant differences between sexes. Among the four GV subtypes, the GSV confluence type was the most prevalent. All limbs with GV reflux were classified within the varicose group, in which GV detection rates were significantly higher than in the primary group. The detection rate of GV reflux increased progressively with higher CEAP classifications. Additionally, detection rates in the SSV reflux group and in the combined reflux group were significantly higher than in the GSV reflux group.

The incidence of GV reflux increased with greater severity of GSV reflux. Ultrasound and DSA demonstrated a high level of concordance in the classification of GV subtypes, supporting the diagnostic accuracy of ultrasound for GV classification. These findings provide a theoretical basis for the use of ultrasound as a preferred diagnostic modality for lower extremity venous diseases (14). The results further contribute data regarding the characteristics of the GV in the Chinese population and may inform future research, clinical evaluation, and the development of individualized treatment strategies.

The high prevalence of the GV in the general population has been documented in multiple studies. Early autopsy investigations reported a detection rate of 94% by Carlo Giacomini, with subsequent studies reporting rates of 82.2%, 85%, 92%, and 95%, respectively (15-18). The overall GV detection rate in this study was 74.0%, which is consistent with previous ultrasound-based reports ranging from 62% to 90%, supporting the reliability of ultrasound as an imaging modality for GV assessment (19-23). Based on a systematic review of the existing literature, the GV was classified into four types in this study, incorporating both common anatomical patterns and complex drainage pathways. This classification enhances structural clarity and improves clinical applicability. The GSV confluence type accounted for the largest proportion, consistent with previous findings (24). Twenty-three GVs (9.7%) exhibited complex confluence with multiple branches, which is highly consistent with results reported by Delis et al. (21). These findings indicate that multiple terminations constitute an anatomical variant with a measurable incidence, further supporting the reliability and generalizability of this classification system. Therefore, during ultrasound evaluation of the GV, careful delineation of its course and branches particularly in complex confluence types is necessary to support appropriate surgical planning, reduce intraoperative risk, and improve treatment outcomes. Due to the limited number of GV reflux-positive cases in this study, the statistical conditions required for a comparative analysis of hemodynamics across different anatomical types were not met. Therefore, no correlational study was conducted. Further in-depth investigation may be pursued by expanding the sample size in the future.

The GV is commonly present in the population and forms part of the lower limb venous network. In this study, the detection rates of both the GV and GV reflux were significantly higher in the varicose group than in the primary group. GV reflux was identified in 15 cases (8.5%), all within the varicose group, with a reflux rate comparable to previous reports (21,24-26). In contrast, Delis et al. reported no significant difference in GV detection rates between normal and varicose groups (21). This discrepancy may be attributable to advancements in ultrasound technology and examination techniques, which provide higher resolution and improved visualization of small GV pathways. Additionally, the implementation of standardized GV measurement protocols in this study may have further improved measurement accuracy and consistency. Classical theory suggests that venous hypertension may result in venous dilation, structural remodeling, and valvular damage (27,28).

As a communicating channel between the SSV and other venous segments, the GV may undergo partial luminal dilation and remodeling in the presence of venous hypertension associated with varicose veins. This process may increase blood flow and enhance detectability on ultrasound examinations. This mechanism may account for the observed trend of increasing GV reflux detection rates with higher CEAP classifications, although intergroup differences did not reach statistical significance. The lack of statistical significance may be related to limited statistical power due to the relatively small number of detected GV reflux cases. Currently, similar investigations remain limited in the literature. Larger sample sizes and multicenter studies are warranted to further clarify these associations and to provide more robust evidence to support clinical evaluation and management.

To further characterize the distribution pattern of the GV, detection rates were compared between bilateral limbs, and a significantly higher detection rate was observed in the right lower limb than in the left. Delis et al. reported no significant laterality difference in GV detection (21). The study population in Delis et al. predominantly comprised patients with pronounced varicose vein symptoms (66.1%). According to the classical theory of venous remodeling secondary to venous hypertension, substantial compensatory dilation of the GV may already have occurred in such patients, potentially attenuating side-specific differences. In contrast, 48.7% of the limbs in the present study were classified as normal following rigorous evaluation, representing a broader disease spectrum and a distribution closer to the physiological baseline. Anatomically, the left common iliac vein passes posterior to the right common iliac artery, creating the potential for physiological compression, known as iliac vein compression (29). This anatomical relationship may promote earlier reliance on deep and pelvic collateral pathways, thereby reducing dependence on the GV as a compensatory channel. Consequently, even in the presence of venous hypertension, morphological changes in the GV may be less pronounced.

According to the “right-side dominance” theory, the iliac vein-inferior vena cava axis on the right side is relatively straighter and wider, functioning as a principal low-pressure outflow pathway for the right lower limb (30). The superficial venous system on this side may therefore rely less on deep pelvic collateral circulation. When venous hypertension develops, compensatory dilation of the GV may occur more readily on the right, increasing its detectability on ultrasound. This aspect has not been extensively investigated in previous studies and requires confirmation through larger, multicenter prospective studies. In clinical practice, comprehensive bilateral limb evaluation is necessary to prevent omission of relevant diagnostic findings in the contralateral limb due to disproportionate focus on the symptomatic limb.

The GV represents a proximal extension of the SSV and an important superficial communicating branch in the lower limb. Its functional status is closely associated with saphenous vein reflux. In this study, the detection rate of GV reflux was significantly higher in limbs with isolated SSV reflux and in limbs with combined reflux than in limbs with isolated GSV reflux, consistent with previous reports (25,22). As a direct continuation of the SSV, reflux can be directly transmitted to the GV, increasing wall tension and inducing secondary GV reflux. When combined with GSV reflux, the overall pressure burden on the superficial venous system further increases, and the GV, as a key communicating branch, becomes more susceptible to involvement. Therefore, the incidence of GV reflux is highest in the combined GSV and SSV reflux group. The association between GV reflux and the severity of saphenous vein reflux was further examined. The detection rate of GV reflux showed a progressive increase with greater severity of GSV reflux, although the difference did not reach statistical significance. Relevant studies addressing this specific association are currently lacking. As a communicating branch connecting the great and SSVs, the GV may be affected when valvular insufficiency of the GSV occurs, allowing venous hypertension to be transmitted to the connected GV segment (24,31). Greater severity of GSV reflux may result in higher reverse pressure transmitted to the GV and prolonged hemodynamic exposure. Therefore, GV reflux should not be regarded as an isolated phenomenon but rather as a manifestation associated with the severity of saphenous vein reflux. Comprehensive and meticulous assessment of the GV is therefore necessary during the management of saphenous vein reflux. Failure to identify this important collateral reflux pathway may contribute to surgical failure or postoperative recurrence. It should be acknowledged that the relatively small number of GV reflux cases in this study may have limited statistical power. Larger, high-quality studies are required to further validate these findings.

Although GV varicosity is relatively uncommon, inadequate preoperative assessment or insufficient intraoperative management may contribute to postoperative recurrence of varicose veins (32). Currently, minimally invasive techniques predominate in the management of GV varicosities, and CHIVA has been reported to reduce recurrence rates (33-35). Accurate ultrasound evaluation is essential for the success of CHIVA, necessitating detailed preoperative assessment of GV reflux, including its location and severity. The origin of GV reflux directly influences clinical management. If the reflux primarily originates from the main trunk of the GSV, ablation of the diseased GSV can eliminate the pressure gradient driving reflux, thereby leading to resolution of secondary GV reflux. If the reflux originates from the SSV or combined deep and superficial venous pathways, targeted treatment of the respective diseased vessels is required, as residual GV reflux may increase the probability of postoperative recurrence. Through precise targeting of reflux sites, the functional blood vessels were preserved to the maximum extent.

This study only included patients with early superficial venous insufficiency classified as C4 or below, and excluded cases with deep venous reflux or complex reflux patterns. Therefore, issues related to advanced-stage disease could not be investigated, and the direction of GV reflux was not explored, which will be addressed in future studies. Furthermore, the potential hemodynamic role of the GV in cases of popliteal vein or saphenopopliteal junction incompetence was not examined due to our exclusion of deep venous reflux, and should be addressed in future research. The consistency of ultrasound and DSA in GV classification was validated, and future multicenter, prospective studies may further corroborate the findings. This study examined sex- and laterality-related differences in GV detection rates, clarified the association between reflux severity and GV parameters, and conducted data analysis in a Chinese population. Additionally, our classification of type A GV was based on continuity with the GSV trunk. Reflux originating from the perineal region via an incompetent posterior accessory GSV (PAGSV) may also contribute to GV incompetence independently of the GSV, a pattern that warrants further investigation in future studies. Although the results provide some reference value, this part of the analysis is relatively weakly correlated with the core research direction of the paper and has limited practical applicability.

Conclusions

In summary, ultrasound was used to assess the anatomical and hemodynamic characteristics of the GV, further elucidating its role and pathological relevance within the lower extremity venous network. The findings confirm the high prevalence of the GV and demonstrate a close association between GV reflux and the development and progression of lower extremity varicose veins. In patients presenting with lower extremity varicose veins, comprehensive ultrasound examination and targeted assessment of the GV are recommended to facilitate early identification of pathological changes and to provide objective evidence to inform clinical diagnosis and therapeutic decision-making.

Acknowledgments

We would like to acknowledge the hard and dedicated work of all the staff that implemented the intervention and evaluation components of the study.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://qims.amegroups.com/article/view/10.21037/qims-2026-0526/rc

Data Sharing Statement: Available at https://qims.amegroups.com/article/view/10.21037/qims-2026-0526/dss

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://qims.amegroups.com/article/view/10.21037/qims-2026-0526/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Ethics Committee of Aerospace Center Hospital (No. 2025-022). Written informed consent was obtained from all participants.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Standring S. Grays anatomy: the anatomical basis of clinical practice. 39th ed. London: Elsevier Churchill Livingstone; 2005:1452-87.
2. Giacomini C. Osservazioni anatomiche per servire allo studio della circolazione venosa delle estremita inferiori Parte I: Delle vene superficiali dell’arto addominale e principalmente della saphena esterna. Giornale della Reale Accademia di Medicina di Torino 1873;14:109-215.
3. Caggiati A, Bergan JJ, Gloviczki P, Jantet G, Wendell-Smith CP, Partsch HInternational Interdisciplinary Consensus Committee on Venous Anatomical Terminology. Nomenclature of the veins of the lower limbs: an international interdisciplinary consensus statement. J Vasc Surg 2002;36:416-22. [Crossref] [PubMed]
4. Muschamp SD, Holdstock JM, Davies VL, Herbert PE, Whiteley MS. Aneurysm of the Giacomini vein. J Vasc Surg Venous Lymphat Disord 2022;10:765-6. [Crossref] [PubMed]
5. Xie H, An YQ, Zhang C, Zhao XN, Wang YY, Niu LY, Liu Y. Application of Ultrasound in Etiological Identification of Recurrent Varicose Veins of Lower Limbs. Chinese Journal of Ultrasound in Medicine 2022;38:213-7.
6. Gloviczki P, Lawrence PF, Wasan SM, Meissner MH, Almeida J, Brown KR, Bush RL, Di Iorio M, Fish J, Fukaya E, Gloviczki ML, Hingorani A, Jayaraj A, Kolluri R, Murad MH, Obi AT, Ozsvath KJ, Singh MJ, Vayuvegula S, Welch HJ. The 2022 Society for Vascular Surgery, American Venous Forum, and American Vein and Lymphatic Society clinical practice guidelines for the management of varicose veins of the lower extremities. Part I. Duplex Scanning and Treatment of Superficial Truncal Reflux: Endorsed by the Society for Vascular Medicine and the International Union of Phlebology. J Vasc Surg Venous Lymphat Disord 2023;11:231-261.e6.
7. Liu G, Oomens D, Graves A, Weiley V, Bevan C, Lamb K, Necas M, Rae D, Paraskevas P, Parsi Y, Adams M, Thoirs K. Ultrasound Assessment for Chronic Venous Insufficiency: Introducing an Evidence-Based Clinical Guideline for Sonographers. Sonography 2026;13:e70028.
8. Lurie F, Passman M, Meisner M, Dalsing M, Masuda E, Welch H, et al. The 2020 update of the CEAP classification system and reporting standards. J Vasc Surg Venous Lymphat Disord 2020;8:342-52. [Crossref] [PubMed]
9. The Vascular Surgery Group of the Chinese Society of Surgery of the Chinese Medical Association. The Vascular Surgery Branch of the China International Exchange Association for Medical and Health Care; The Vascular Surgery Branch of the Taiwan-Beijing Medical and Health Exchange Association; The Vascular Medicine Professional Committee of the Chinese Research Hospital Association; The Peripheral Vascular Disease Management Branch of the Chinese Geriatrics Society; The Vascular Surgery Branch of the Chinese Microcirculation Society. China Guidelines for Diagnosis and Treatment of Chronic Venous Diseases. National Medical Journal of China 2019;99:3047-61.
10. Bush RG, Hammond K. Treatment of incompetent vein of Giacomini (thigh extension branch). Ann Vasc Surg 2007;21:245-8. [Crossref] [PubMed]
11. Coleridge-Smith P, Labropoulos N, Partsch H, Myers K, Nicolaides A, Cavezzi A. UIP. Duplex ultrasound investigation of the veins in chronic venous disease of the lower limbs--UIP consensus document. Part I. Basic principles. Vasa 2007;36:53-61.
12. Cavezzi A, Labropoulos N, Partsch H, Ricci S, Caggiati A, Myers K, Nicolaides A, Smith PC. Duplex ultrasound investigation of the veins in chronic venous disease of the lower limbs--UIP consensus document. Part II. Anatomy. Eur J Vasc Endovasc Surg 2006;31:288-99.
13. Theivacumar NS, Dellagrammaticas D, Mavor AI, Gough MJ. Endovenous laser ablation (EVLA) of great saphenous vein to abolish “paradoxical reflux” in the Giacomini vein: a short report. Eur J Vasc Endovasc Surg 2007;34:229-31. [Crossref] [PubMed]
14. De Maeseneer MG, Kakkos SK, Aherne T, Baekgaard N, Black S, Blomgren L, et al. Editor’s Choice - European Society for Vascular Surgery (ESVS) 2022 Clinical Practice Guidelines on the Management of Chronic Venous Disease of the Lower Limbs. Eur J Vasc Endovasc Surg 2022;63:184-267. [Crossref] [PubMed]
15. Kosinski C. Observations on the Superficial Venous System of the Lower Extremity. J Anat 1926;60:131-42.
16. Mercier R, Fouques P, Portal N, Vanneuville G. Surgical anatomy of the small saphenous vein. Surgical results in the radical treatment of varices of the lower limb. J Chir (Paris) 1967;93:59-70.
17. Prakash Kumari J, Nishanth Reddy N, Kalyani Rao P, Preethi Ramya T. Singh G. A review of literature along with a cadaveric study of the prevalence of the Giacomini vein (the thigh extension of the small saphenous vein) in the Indian population. Rom J Morphol Embryol 2008;49:537-9.
18. Stolic E. Posterior subaponeurotic vein of the thigh. C R Assoc Anat 1970;149:1016-26.
19. Engel AF, Davies G, Keeman JN. Preoperative localisation of the saphenopopliteal junction with duplex scanning. Eur J Vasc Surg 1991;5:507-9. [Crossref] [PubMed]
20. Caggiati A. Fascial relationships of the short saphenous vein. J Vasc Surg 2001;34:241-6. [Crossref] [PubMed]
21. Delis KT, Knaggs AL, Khodabakhsh P. Prevalence, anatomic patterns, valvular competence, and clinical significance of the Giacomini vein. J Vasc Surg 2004;40:1174-83. [Crossref] [PubMed]
22. Liu JL, Ding JH, Zhang FX. Clinical Observation of Giacomini Vein. Chinese Journal of General Surgery 2014;29:809-10.
23. Nowak-Tarnawska A, Reina-Gutierrez L. The vein of Giacomini: an in-depth review of its anatomy, hemodynamics, and treatment alternatives. Phlebolymphology 2024;31:4-12.
24. Georgiev M, Myers KA, Belcaro G. The thigh extension of the lesser saphenous vein: from Giacomini’s observations to ultrasound scan imaging. J Vasc Surg 2003;37:558-63. [Crossref] [PubMed]
25. Veltman HJ, Zollmann P, Zollmann M, Zollmann C, Berger I, Preller A, Mendoza E. Reflux origin of the insufficient small saphenous vein by duplex ultrasound determination and consequences for therapy considering the saphenopopliteal junction type. J Vasc Surg Venous Lymphat Disord 2023;11:1114-21. [Crossref] [PubMed]
26. Shin M, Kim Y, Kim DI, Lee KB. The frequency of occurrence and clinical significance of the giacomini vein. Korean J Vasc Endovasc Surg 2007;23:39-42.
27. Nadasy GL, Patai BB, Molnar AA, Hetthessy JR, Tokes AM, Varady Z, Dornyei G. Vicious Circle With Venous Hypertension, Irregular Flow, Pathological Venous Wall Remodeling, and Valve Destruction in Chronic Venous Disease: A Review. Angiology 2026;77:271-95. [Crossref] [PubMed]
28. Kuk H, Jeanneret C, Noppeney T, Korff T. The biomechanics of venous remodeling. In: Hecker M, Duncker DJ, editors. Vascular Mechanobiology in Physiology and Disease. Cham: Springer International Publishing; 2021:167-89.
29. Mousa AY, AbuRahma AF. May-Thurner syndrome: update and review. Ann Vasc Surg 2013;27:984-95. [Crossref] [PubMed]
30. Standing S. Gray’s Anatomy: The Anatomical Basis of Clinical Practice. 42nd ed. London: Elsevier; 2021.
31. Engelhorn CA, Engelhorn ALDV, de Oliveira EDS, de Macedo JM, Anizelli LB, de Mendonça MLO. The role of the giacomini vein in preoperative mapping of lower limb varicose veins. J Vasc Bras 2024;23:e20240058. [Crossref] [PubMed]
32. Goyal VD, Misra G, Pahade A. Vein of Giacomini can lead to the recurrence of varicosities after endovenous laser ablation of varicose veins. Indian J Thorac Cardiovasc Surg 2023;39:286-8. [Crossref] [PubMed]
33. Guzelmansur I, Oguzkurt L, Koca N, Andic C, Gedikoglu M, Ozkan U. Endovenous laser ablation and sclerotherapy for incompetent vein of Giacomini. Phlebology 2014;29:511-6. [Crossref] [PubMed]
34. Dong YM, Wang LJ, Wang SM, Jiang HL, Meng LY, Tian K. Observation on the Efficacy of High-Position Varicose Vein Ligation and Debridement Combined with Ultrasound-Guided Foam Sclerotherapy for Varicose Veins Complicated with GV Dysfunction. Zhejiang Medical Journal 2021;43:423-5.
35. Ma XH, Li M, Sun GY, Zhang J, Liu J, Xue LJ, Liu XP, Guo W. Effect of CHIVA strategy on venous valvular insufficiency in lower extremity. Academic Journal of Chinese Pla Medical School 2020;41:1053-7.