An Anatomical Study Of The Medial Femoral Circumflex Artery Base On Three-dimensional Computed Tomographic Angiography

BackgroundThe fracture of the femoral neck is a common type of fracture, it often occurs in the elderly. After the femoral neck fracture, the blood supply of the femoral head can suffer severe damage. The main complications of the femoral neck fracture are nonunion and osteonecrosis of femoral head, some scholars reported the incidence respectively at 15%(nonunion),20%-30%(osteonecrosis of femoral head). The deep branch of the medial femoral circumflex artery and the ascending branch of the lateral femoral circumflex artery are the main arteries which supply the blood to the femoral head and the femoral neck. Now scholars at home and abroad think that the femoral neck’s blood supply more than 70% comes from the medial femoral circumflex artery. Scholars had already studied and found that the vascular volume of the lateral femoral circumflex artery and the medial femoral circumflex artery had changed after the femoral neck fracture, which affects the blood circulation of the femoral head. It may be one kind of the pathogenesis of ischemic necrosis of femoral head after the femoral neck fracture. As people’s live are longer, the incidence of the femoral neck fracture and osteonecrosis of the femoral head is increasing. Therefore understand the anatomical characteristics of the medial femoral circumflex artery which is the main blood supply artery of the femoral head and the femoral neck, will have very important significance to protect the blood supply of the femoral head and the treatment of ischemic necrosis of the femoral head.ObjectiveThe medial femoral circumflex artery is originate from the femoral profound artery or femoral artery. In the operation of some hip surgery, such as the back of the acetabulum fractures open reduction and internal fixation, Kocher-Langenbeck admission passage, and interventional therapy, it can easy to damage the medial femoral circumflex artery trunk or the branch of the artery. Due to the blood supply particularity of the medial femoral circumflex artery, it is prone to ischemic necrosis of femoral head after the medial femoral circumflex artery is injuried. It will be helped to prevent the damage to the medial femoral circumflex artery, while understanding the characteristics of the anatomy of the medial femoral circumflex artery and the relationship between the medial femoral circumflex artery with the main anatomical marks. In the past, the color Doppler and digital subtraction angiography (DSA) could be used to study the status of the blood vessels. But the color doppler can’t be used to subtly describe the blood supply situation of the deep smaller blood vessels. DSA is a kind of examination witch can cause damage to human’s body, it needs high operation requirements, and can produce false positive results due to the lack of injection speed or dose. Some scholars used three-dimensional magnetic resonance angiography to study and observe the medial femoral circumflex artery, but it took a long time to complete the image, also the soft tissue images tended to impact the assessment of the relationship between the medial femoral circumflex artery with the main anatomical marks, and impact the distance measurement with each other, moreover the literature reported the data in detail rarely. In the past, scholars adopted the formalin fixed specimens to research the medial femoral circumflex artery, but due to the limited amount of specimens, loss of physiologic, it made the results of the study has certain limitations.Past research methods are either limited amount of specimens, or can not display accurately, or can’t measure subtly, it is not enough to understand the characteristics of the anatomy of the medial femoral circumflex artery. So to explore a simple and fast way to reflect the status of the medial femoral circumflex artery in physiological conditions intuitively is urgent and needed. Since the three-dimensional CT has been applied to clinical examination and research, qualitative changes have taken place in medical development. It provides the stereoscopic three-dimensional visual perception for clinical, and makes the image more intuitive to reflect the things. It makes the understanding of the morphology of the things to appear more image and real. Three-dimensional computed tomographic angiography(3DCTA) is a minimally invasive techniques, based on the computer X-ray tomography angiography (CTA). It can target vascular imaging under the normal physiological conditions. The reconstruction Images can be well to show the position relationship between the bones with the adjacent blood vessels. In the past, some scholars also adopted 3DCTA to research blood vessels, But the anatomical morphology of the medial femoral circumflex artery in state of 3DCTA, and the relationship between the medial femoral circumflex artery with the main anatomical marks (osseous marks, especially greater trochanter and lesser trochanter), were not described in detail. Thus when in a hip operation, it was inconvenience to identify the location of the blood vessels by applied the osseous marks. This study plans to use the 3DCTA technology to describe the origin, direction, position, anatomical morphology of the medial femoral circumflex artery, and its relationship with the main anatomical marks,and adjacent arteries. So as to provide the anatomical references for judgement of the condition of a hip injury, related treatment and operative approach.MethodsTo do this research the 3DCTA data were collected who underwent 3DCTA for various reasons, in nanfang hospital, southern medical university, from March 2012 to June 2014 for examination of the pelvis and lower extremities (femoral region). The CT scanners was Somatom Definition. Inputted the data into the matching processing software (Inspace), used the volume rendering(VR) technology to do the three-dimensional reconstruction, and then outputted the image through the workstation (picture archiving communication system, PACS). Excluded the patients who have external iliac artery occlusion, hip tumors, and history of pelvic and hip fracture or operation, which could affect the medial femoral circumflex artery imaging or change the position of the medial femoral circumflex artery.This research included 103 patients, they were 55 men(mean age,54.7±15.9 years) and 48 women(50±16.1 years).We used the PACS workstation which provides Image scaling and rotation function, image measurement function to observe and measure the medial femoral circumflex artery.① The location, origin and course characteristics of the medial femoral circumflex artery were observed. The condition of branches of the medial femoral circumflex artery, and its relationship with the adjacent main artery were observed.② According to the course shape of the medial femoral circumflex artery trunk which express in the 3DCTA reconstruction images, it could be divided into 3 types of anatomical morphology:screw type, which presented multiple spirals and crimp state; circuitous type, which had circuitous and bending state; straight type, the trunk of the artery went relatively flat. And we analyzed the frequency of various kinds of anatomical morphology. ③To do the following measurement by PACS workstation, the length of the artery trunk (L) was measured. On the anteroposterior position, the distances between the origin (A) of the artery to the main anatomical marks[the peak of greater trochanter (B),the inward peak of lesser trochanter (C),and the crosspoint (D) of the femoral artery and the pubic edge or the acetabulum inlet edge] were measured. The distance between the point A and point E was measured. And the point E was the starting point of the femoral profound artery. The diameter of the opening (inner diameter) of the medial femoral circumflex artery trunk was measured. ④ On the anteroposterior position, we connected the peak of greater trochanter (B) with the inward peak of lesser trochanter (C),and made a vertical line through the midpoint (O) of the line(BC).The flat could be divided into four quadrants, contained include upper outside quadrant, inner upper quadrant, outer under quadrant, inner under quadrant. The spatial position of the origin of the medial femoral circumflex artery was observed.The statistical software of SPSS 13.0 was used to do this research. Measurement data was expressed with" x±s". Comparisons of the age and the measurements[the length of the medial femoral circumflex artery trunk (L), the distances between the origin (A) of the artery to the main anatomical marks(AB、AC、AD、AE)]were conducted between genders, by using the t test of two independent sample. There were statistical differences, if P<0.05.ResultsIn this research,there were 103 patients(55 men,48 women,206 hips in total).The following were the results, ① 98.1%(101/103) of the patients had their femoral profound arteries originated from the femoral artery which originated from the external iliac artery, at a distance below the inguinal ligament. The origin openings of the femoral profound arteries were located below the pubic edge or acetabulum front edge, and above the connection line of the greater trochanter and the lesser trochanter. 1.9%(2/103) of the patients had their femoral profound arteries higher originated from the external iliac artery, which located on the pubic edge or acetabulum front edge. Their femoral profound arteries shared the artery trunk with the femoral artery in the groin. ② The medial femoral circumflex artery could be divided into 2 types, originated from the femoral artery and originated from the femoral profound artery. The origin of the medial femoral circumflex artery,2.9%(3/103) of the subjects had their bilateral medial femoral circumflex arteries originate from the femoral artery, 94.2%(97/103) had their bilateral medial femoral circumflex arteries originate from the femoral profound artery, and 2.9%(3/103) had one medial femoral circumflex artery originate from the femoral artery and the other from the femoral profound artery. The origin of the lateral femoral circumflex artery,6.8%(7/103) of the subjects had their bilateral lateral femoral circumflex arteries originate from the femoral artery,90.3%(93/103) had their bilateral lateral femoral circumflex arteries originate from the femoral profound artery, and 2.9%(3/103) had one lateral femoral circumflex artery originate from the femoral artery and the other from the femoral profound artery. Therefore, origination from the femoral profound artery, both the femoral circumflex artery and the lateral femoral circumflex artery, were in the majority. ③The relationship between the medial femoral circumflex artery with the lateral femoral circumflex artery. There were 103 cases of patients in total,3 cases of the medial femoral circumflex arteries and 7 cases of the lateral femoral circumflex arteries originated from the femoral artery.3 cases existed a mixed state (one lateral femoral circumflex artery originated from the femoral artery, medial femoral circumflex artery originated from the femoral profound artery, and the other lateral femoral circumflex artery originated from the femoral profound artery, medial femoral circumflex artery originated from the femoral artery). The other 90 cases of patients had their bilateral medial femoral circumflex artery and lateral femoral circumflex artery originate from the femoral profound artery. Their relationship was that,75.6%(68/90)of these cases, the medial femoral circumflex arteries sent out first and the lateral femoral circumflex arteries sent out later; 17.8%(16/90) of these cases, the lateral femoral circumflex arteries sent out first and the medial femoral circumflex arteries sent out later; 6.7%(6/90) of these cases, the medial femoral circumflex arteries and the lateral femoral circumflex arteries sent out in the same flat. ④ The morphology of the medial femoral circumflex artery trunk,1.9%(4/206)、 76.7%(158/206) and 21.3% (44/206) of the subjects had the artery of screw type, of circuitous type and of straight type. The circuitous type was in the majority among them. The trunk and branch of the medial femoral circumflex artery could be displayed by the 3DCTA technology. The artery trunk went towards inside and behind after it was issued, divided into branches along the course. The ascending branch, descending branch and deep branch could be seen. The ascending branch went upward and towards obturator formamen. The descending branch went downward. The deep branch was the continuation of the medial femoral circumflex artery trunk, which continued to go around the back of the femoral neck, and finally went to the outward and upper direction, became the main blood supply of the femoral head and the femoral neck. ⑤In the state of stand upright and pelvis no tilt,44.7%(92/206) of the medial femoral circumflex artery trunk went inside and above the lesser trochanter,35.9%(74/206) of the artery trunk went around the basal parts of the femoral neck, and 19.4%(40/206) of the artery trunk went around the middle part of the femoral neck. The spatial position of the origin of the medial femoral circumflex artery which originated from the femoral profound artery, was located in the front of the greater trochanter and the lesser trochanter in the Sagittal position; and located in the inner upper quadrant in anteroposterior position. It was located below the pubic edge or acetabulum front edge, and above the connection line of the greater trochanter and the lesser trochanter. ⑥ The distances between the origin of the medial femoral circumflex artery to the main anatomical marks, male vs. female[AB (32.80±14.15 mm vs.34.85±15.24 mm,P=0.316)、AC(14.79±7.10 vs.13.38±5.55 mm, P=0.112)、 AD(17.38±8.41 vs.17.64±10.18 mm, P=0.842)、AE (9.76±7.77 mm vs.11.16±9.26 mm, P=0.238)],there were no statistical difference between males and females regarding the distances between points AB,AC,AD or AE (P>0.05).The length of the medial femoral circumflex artery trunk, male 17.00±8.80 mm, female 17.45±10.59 mm, P=0.741, there were no statistical difference between males and females regarding the length of the artery trunk (P>0.05)。There were 103 patients were researched, the diameter (inner diameter) of the opening of the medial femoral circumflex artery was 1.1～4.7 mm, mean 2.09±0.74 mm.Conclusions① To do this research the three-dimensional computed tomography angiography (3DCTA) technology is used for stereo observation of the medial femoral circumflex artery. According to the need, It can display the reconstructed images of the bone and blood vessel individually or in combination, and rotate and zoom to any angle. The artery can be showed Perfectly.② The origin of the medial femoral circumflex artery is not constant. It can originate from the femoral profound artery, and can also originate from the femoral artery. The position of the medial femoral circumflex artery can be high, or be low. The relationship between the artery with the lateral femoral circumflex artery is not constant. So we must pay attention to the existence of its anatomical variations,when doing clinical treatment.③ The anatomical morphology and course characteristics of the medial femoral circumflex artery can be shown vividly in this research through 3DCTA.The length of the artery trunk was measured. And the distances between the origin of the artery to the main anatomical marks (AB、AC、AD、AE) were measured. we find that there are no statistical difference between males and females regarding the length of the artery trunk, or the distances between points AB,AC,AD or AE (P>0.05)④ With the help of the main anatomical marks, we can identify the location of the medial femoral circumflex artery, so as to prevent the iatrogenic injury. It can be used to provide anatomical reference for clinical evaluation,treatment and operative approach of hip injury.