| BackgroudNowadays, the incidence of uterine malignancies has been showed a trend of increasing, which young patients occupied most, and occurred in cervical cancer especially. Cervical cancer has been the most commonly gynecologic cancer and ranked as the second most frequent cancer in women in the world. Nodal metastasis seems to be an important channel of cancer spread in most cases and lymph node involvement has been a major prognostic factor in uterine malignant tumor. Radical hysterectomy and pelvic lymphadenectomy have been the standard treatment for uterine malignant tumor and lymphadenectomy has been an integral part in gynecological cancer surgery. It has important significance for gynecologic cancer prognosis and treatment to obtain pelvic lymphadenectomy.It is well known that the pelvic anatomy of females were complex, as there were so many tissues and organs such as vessels, pelvic, nerve and muscle which from urinary systems, genital systems, digestive systems. There were also so many lymph-vessels and lymph nodes, which accompany with associated vascular. The density distribution and abundant blood stream characteristics of tortuous pelvic vascular branches that associated with pelvic lymphadenectomy has made the surgery of pelvic lymphadenectomy, especially laparoscopic pelvic lymphadenectomy difficult and risking, vascular injuries during the surgical procedure predominantly involve veins and may lead to massive, potentially life-threatening intraoperative bleeding. To standardize the operation techniques and decrease the complications, gynecologic oncologist should acquisition the acknowledgement of pelvic vascular anatomy detailed. But the complicated characteristics of females’pelvic made them been the difficulty and blindness of anatomy and clinical research, especially the veins. However, in recent years, the widely use of interventional therapy, transvaginal operation and the laparoscope technology in gynecology disease diagnosis and treatment, there were also a higher request of the acknowledgement of pelvic vascular anatomy.The recent anatomic study of females’pelvic vascular network mainly derived from autopsy and medical image technology. Research on cadaveric specimens has several limitations. Vessel structure alterations may occur and contribute to the significant differences observed between vascular structures of the cadaver and the in vivo situation, with drastic postmortem changes in intravascular fluid and protein structures, as well as enzymatic processes. What’s more, these studies were limited by the acquisitiveness of cadaver specimens. The technology of digital subtraction angiograph (DSA) was widely applied in clinical, scientific research and teaching in the early. It has been a practical technique for studying the anatomy of vascular as pelvic vascular branches could be displayed clearly. But the operation were complicated and traumatic, it can’t be a clinical routine inspection. To the contrary, the technologies of computed tomography angiography (CTA) and magnetic resonance angiography (MRA) were used for vascular anatomy by more and more researchers with the crossing from invasive to noninvasive. At the same time, the anatomic improved from cadavers to in vivo, macroscopic to microscopic, simple description to quantitative evaluation.The research published related to pelvic vascular network mostly focus on arteries based on different methods. Lacking of plasticity made veins collapsed and different from in vivo situation with the morphology and location changed, so there were less researches about pelvic veins, and the study combined arteries and veins were much less. Multi-slice CT could make the enhancement of arteries and veins clearly, and our team had explored the methods of reconstructing the pelvic vascular network three-dimensional model. The reconstructed three-dimensional model of pelvic vascular network based on CTA data could visualize the anatomy of pelvic vascular network intuitively, allow surgeons to preoperatively design. Nevertheless, the techniques of digital anatomy are technique-dependent and time-consuming. Obviously, it is unpractical for surgeons to perform patient-specific 3D reconstructions for each patient in most hospitals.In order to clarify the dimensional anatomy between the pelvic artery and vein, we collected a large number of CTA data. This study divided inti two parts:the first part is to observe the structural features of iliac veins posterior to common iliac artery bifurcation related to pelvic lymphadenectomy through the constructed digital three-dimensional model in vivo for pelvic arteriovenous network of female based on CTA; second part intends to investigate the dimensional positional relationship of common iliac artery bifurcation and internal/external iliac vein confluence through measure related geometric parameters of the constructed digital three-dimensional model in vivo for pelvic arteriovenous network of female based on CTA.Part one Structural features of iliac veins posterior to common iliac artery bifurcation[Objective]To observe the structural features of iliac veins posterior to common iliac artery bifurcation related to pelvic lymphadenectomy through the constructed digital three-dimensional model in vivo for pelvic arteriovenous network of female based on CTA.[Method]1. Consecutive patients undergoing pelvic computer tomography angiography (CTA) scan with thin layer (less than 1 mm) for primary gynecologic diseases in Nanfang Hospital of Southern Medical University from September 2013 to September 2015 were recruited. Studies were excluded if pelvic mass, previous pelvic surgery or uterus enlarged obviously to oppress iliac vessels bifurcation were identified since these conditions are known to significantly alter anatomy. The images were exported in DICOM format for storage.2. The CTA data in DICOM format were imported in software Mimics 14.01 (Materialise Company, Belgium). Through several algorithms, such as segmentation, thresholding, boolean operation and region growth technique,3D models of vascular structures, including arteries and veins, were obtained. Digital three-dimensional model of pelvis were constructed with unenhanced phase data, digital three-dimensional model of artery were constructed with arterial phase data, and digital three-dimensional model of veins were constructed with venous phase data. The digital three-dimensional models were exported in STL format for storage.3. The digital three-dimensional models of pelvis and veins were imported into arterial phase data for registration respectively. Then investigate the anatomic features of iliac veins posterior to common iliac artery bifurcation in the window of three-dimensional view with MIMICS software.[Results]1.442 digital three-dimensional models in vivo for pelvic arteriovenous network of female based on CTA were reconstructed by using Mimics software. The digital model clearly showed the abdominal and pelvic arteriovenous network in physiological state. The 3D models of vessels could intuitively display the relationships between pelvic arteries and veins. And provided a 3D overview from mutil-direction and mutil-angles for doctors.2. Five patterns of veins posterior to CIAB were found:confluence of common iliac veins (CCIV), common iliac vein (CIV), no great vein (N), external/internal iliac veins confluence (EIIVC) and external iliac vein (EIV). There were four patterns of iliac veins beneath CIAB in left ("CIV" 13.8%, "N" 71.27%, "EIIVC" 1.58% and "EIV" 13.35%), while five patterns in right ("CCIV" 8.82%, "CIV" 77.38%, "N" 1.58%, "EIIVC" 6.11%, and "EIV" 6.11%). The bilateral distributions of iliac veins beneath CIAB were significantly different (p< 0.001).3. The venous diameters immediately posterior to the left CIAB were 14.36 ± 2.47 mm in "CIV",0 in "N",15.44 ± 1.42 mm in "EIIVC", and 12.01 ± 1.33 mm in "EIV", respectively. The venous diameters in "CIV" and "EIIVC" were significantly larger than those in "EIV" (P< 0.05). The venous diameters immediately posterior to the right CIAB were 18.34 ± 2.21 mm in "CCIV",14.36 ± 2.47 mm in "CIV",0 in "N",15.43 ± 1.40 mm in "EIIVC", and 12.00 ± 1.33 mm in "EIV", respectively. The venous diameters in "CCIV", "CIV" and "EIIVC" were significantly larger than those in "EIV" (P< 0.05). The venous diameters immediately posterior to the left CIAB in "CIV" and "EIIVC" were significantly larger than right, but there were no difference in "EIV" between the two sides.[Conclusion]The structure of veins posterior to common iliac artery bifurcation were complex, and this study confirmed the extensive variability of the bilateral common iliac vessels bifurcation in Chinese females. The venous diameters immediately posterior to CIAB in "CCIV", "CIV" and "EIIVC" were significantly larger than that in "EIV". It could help surgeons reduce the risk of vascular injury, hemorrhage or transfusion in pelvic lymphadenectomy.Part two Distribution features of veins posterior to common iliac artery bifurcation[Objective]To investigate the distribution features of iliac veins posterior to common iliac artery bifurcation or dimensional positional relationship of common iliac artery bifurcation between internal/external iliac vein confluences through measure related geometric parameters of the constructed digital three-dimensional model in vivo for pelvic arteriovenous network of female based on CTA.[Method]1. Consecutive patients undergoing pelvic computer tomography angiography (CTA) scan with thin layer (less than 1 mm) for primary gynecologic diseases in Nanfang Hospital of Southern Medical University from September 2013 to September 2015 were recruited. Studies were excluded if pelvic mass, previous pelvic surgery or uterus enlarged obviously to oppress iliac vessels bifurcation were identified since these conditions are known to significantly alter anatomy. The images were exported in DICOM format for storage.2. The CTA data in DICOM format were imported in software Mimics 14.01 (Materialise Company, Belgium). Through several algorithms, such as segmentation, thresholding, boolean operation and region growth technique,3D models of vascular structures, including arteries and veins, were obtained. Digital three-dimensional model of pelvis were constructed with unenhanced phase data, digital three-dimensional model of artery were constructed with arterial phase data, and digital three-dimensional model of veins were constructed with venous phase data. The digital three-dimensional models were exported in STL format for storage.3. The digital three-dimensional models of pelvis and vein were imported into arterial phase data for registration respectively. Then investigate the dimensional positional relationship of common iliac artery bifurcation and internal/external iliac vein confluence in the window of three-dimensional view by software MIMICS quantitatively. To quantify the courses of iliac veins posterior to CIAB, the linear distances (di) and their distances on sagittal (ds), coronal (dc) and perpendicular (dp) axes from CIAB to external/internal iliac veins confluence (EIIVC) were geometrically measured.[Results]The linear distances of the pattern "CCIV" from CIAB to EIIVC in right were 44.80 ± 8.90 mm. Their ds, dc, and dp were 21.27 ± 4.47 mm,18.73 ± 6.22 mm and 33.44 ± 9.61 mm respectively. Whereas the pattern "CCIV" were not observed in left.The linear distances of the pattern "CIV" from CIAB to EIIVC in left were 33.08 ± 10.97 mm. Their ds, dc, and dp were 10.65 ± 9.20 mm,15.26 ± 5.00 mm and 25.77 ± 9.79 mm respectively. And the linear distances of the pattern "CIV" from CIAB to EIIVC in right were 35.26 ± 10.45 mm. Their ds, dc, and dp were 15.83 ± 6.05 mm, 15.55 ± 5.35 mm and 26.34 ± 10.42 mm respectively.The linear distances of pattern "N" from CIAB to EIIVC in left were 29.20 ± 11.07 mm. Their ds, dc, and dP were 3.61 ± 7.90 mm,14.65 ± 5.78 mm and 21.32 ± 13.52 mm respectively. And the linear distances of pattern "N" from CIAB to EIIVC in right were 30.24 ± 7.62 mm. Their ds, dc, and dp were 7.64 ± 8.09 mm,15.64 ± 3.97 mm and 22.29 ±10.51 mm respectively.The linear distances of pattern "EIIVC" from CIAB to EIIVC in left were 16.02 ± 4.56 mm. Their ds, dc, and dp were 2.20 ± 4.44 mm,11.50 ± 3.72 mm and 10.60 ± 7.22 mm respectively. And the linear distances of pattern "EIIVC" from CIAB to EIIVC in right were 20.61 ± 4.52 mm. Their ds, dc, and dp were 9.50 ± 4.49 mm, 11.85 ± 3.34 mm and 12.66 ± 4.95 mm respectively.The linear distances of pattern "EIV" from CIAB to EIIVC in left were 16.15 ± 6.25 mm. Their ds, dc, and dp were 5.72 ±7.13 mm,8.14 ± 8.29 mm and 1.40 ± 10.13 mm respectively. And the linear distances of pattern "EIV" from CIAB to EIIVC in right were 14.17 ± 4.10 mm. Their ds, dc, and dp were 1.67 ± 3.45 mm,11.83 ± 4.01 mm and 3.20 ± 7.40 mm respectively.[Conclusion]The distances from CIAB to EIIVC, including linear distances and their ds, dc, and dv showed significant differences. The overall trend of di, ds, dc and dv from CIAB to EIIVC is a gradual decrease ("CCIV"> "CIV"> "N">"EIIVC">"EIV"). |
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