The Anatomic And Experiment Study Of Vascular Injuries Secondary To Pelvic Fractures

Objectives: The hemorrhage is a serious complication of instability pelvic fracture. The shock rate is 30%, the mortality rate is 60%. Although originations of hemorrhage have been thought as follows: the arterial disruption, vein disruption, fracture border, soft tissues, the real originations can't be identification. Is artery or vein injuried ? Is big vessel or small vessel injuried ? which is still a problem. Some scholars think that fracture pattern can predict arterial injury, another scholars think that it can't. There are also many arguments about the diagnosis and treatments of the pelvic fracture with hemorrhage. Some scholar think that patient with pelvic facture should take X-ray and CT before taking angiography, another don't think so. The controversy remains over optimal initial management, Some think that instability pelvic fracture patients with hemodynamic instability should be taken immediate external fixation (EX FIX). Others feel ongoing hemodynamic instability indicates arterial bleeding, and prefer early angiography (ANGIO) before EX-FIX. Our aim is that study the relations of iliac vessel's branches with pelvic sides and lumbosacral plexus and pelvic ligaments by anatomy of pelvic cadaveris. We retrospectively analysis 55 patients of pelvic fracture with hemorrhage, discuss the relations of fracture location, classifications and vessels' injury. Discussing the mechanisms of vessel injury and methods of diagnose and treatment of the pelvic vessels injuries.Methods: The study was performed in 20 formalin-fixed specimens of Chinese cadaver pelvises .We observed the relationship of the patterns of the iliac arterial branches and type with the pelvic ligaments and sacral nerves, and observed the location of the pelvic vessels on the pelvic sides, and measured the vertical distance from vessels to pelvic sides, and observed thecollateral circulations of the pelvic arteries. The results were recorded by mapping, taking pictures. The iliac vein were studied as above. From 1999.1-2003.10 , 55 patients with pelvic artery injuries were observed. The patient ages ranged from 21 to 52 years of age(mean,34.5), and 42 were male, 13 were female. Of 55 patients, 28 patients were struck by automobiles, 12 patients suffered crush injures , 9 patients fell from heights, 6 patients were involved in other accident. Mean injury severity score was 39±16 with a range from 16 to 66. All patients were hypotensive with systolic blood pressures less than 90 mmHg on arrival to hospital. The average amount of blood transfusion was 2886 ml. All patients underwent iliac artery angiography. According to pelvic fracture X-ray : posterior pelvic fracture 21, anterior pelvic fracture 12, fracture of acetabulum 6, combined pelvic fracture 16.Results: The results of anatomy: The diameter of the pelvic vessels which were shorter than 3 mm were iliolumbar arteries and veins, lateral sacral arteries and veins, obturator arteries and veins. The diameter of pelvic vessels from 3 to 5mm were superior gluteal arteries and veins, inferior gluteal arteries and veins, internal pudendal arteries and veins. The diameter of pelvic vessels which were bigger than 5mm were common iliac arteries and veins, internal iliac arteries and veins, external iliac arteries and veins. The vertical distance from pelvic vessels to pelvic sides which were greater than 10mm were common iliac arteries and veins, internal iliac arteries and veins, external iliac arteries and veins, which were smaller than 10mm were iliolumbar arteries and veins, obturator arteries and veins, lateral sacral artery, superior gluteal arteries and veins, inferior gluteal arteries and veins. The differences had significant (p<0.05). The length of the left iliac common artery was 44.17+/-7.28mm, and the length of right iliac common artery was 41.28+/-6.74mm.The left was longer than the right (p<0.05). The length of the left external iliac artery was 105.42+/-7.13mm, and the length of right external iliac artery was 11.63+/-7.23mm. The right was longer than the left (p<0.05). The diameter of the pelvic arteries which the left comparedwith the right had no significant differences. According to the classification by Zhong shizhen about the patterns of the branches of the internal iliac artery, the internal iliac artery were classified into 5 types: type I was 22 sides (25%), type II 8 sides (17.5%),type III 8 sides (17.5%), type IV 2 sides (5%), type V 1 side (2.5%). In 87.5% cases the superior gluteal artery passed through iliolumbar plexus , and in 52.5% cases the inferior gluteal artery passed through iliolumbar plexus. In all the cases , we found the circumflex of iliolumbar- deep iliac circumflex artery.There are widely vascular anastomosis between the iliac arterial blanches. They can be divided into three types: (1) The communicating anastomosis, the diameter bigger than 2mm. They are iliolumbar artery and superior gluteal artery, superior gluteal a and obturator artery, obturator artery and external iliac artery. (2) The direct anastomosis, the diameter between 1-2mm..They are lumbar artery and iliollumbar artery, iliollumbar artery and deep iliac circumflex artery, between obturator arteries. (3) The network anastomosis, the diameter small than lmm.There are widely vascular anastomosis between the iliac vein blanches. The become vein plexus. We observe the main vein plexus that are relation to the pelvic fracture .They are sacral vein plexus, bladder vein plexus, posterior pubic vein plexus.Of 55 patients, 50 patients suffered injury of internal artery or its branches, 3 patients with occlusion of the external iliac artery, 1 patient with external iliac artery disruption, 1 patient with occlusion of common iliac artery, 3 cases died, mortality rate was 5.45%. The injured vessels were common iliac artery 1, external iliac arteries 4, internal iliac arteries 2, superior gluteal arteries 42, iliac lumber arteries 24, lateral sacral arteries 24, inferior gluteal arteries 8, obturator arteries 15, pudendal arteries 6. There were 64 injured vessels in posterior pelvic fracture and 17 in anterior pelvic fracture, hree patients with occlusion of the external iliac artery, twenty-three patients with the disruption of the internal iliac artery branches. Three casese died. According to the Yongth-Bergess' classification : type LC8 cases, type APC25cases, type VS lOcases, type CM 12 cases. The superior gluteal artery disruptions were 32 cases, acute artery embolizations 23 cases , the successful incidence was 95.55%.Conclusions: According to the diameter of pelvic vessels, the pelvic vessels were classified into three kinds: (1) small diameter vessels (D<3mm): iliaclumber artery, lateral sacral artery, obturator artery. (2) medium diameter vessels (3mm 5mm): common iliac artery and vein, internal iliac artery and vein, external iliac artery and vein. According to the distance from vessels to pelvic sides, the pelvic vessels were classified into two sorts: (1) close bone vessels(distance<10mm): iliolumbar artery and vein, lateral sacral artery and vein, obturator artery and vein, superior gluteal artery and vein, inferior gluteal artery and vein, internal pudendal artery and vein. (2) distant place artery ( distance >10mm): common iliac artery and vein, internal iliac artery and vein, external iliac artery and vein. 2. The mechanisms of pelvic vessels injury were classified into direct injury and indirect injury. In direct injury, the injury was caused by the chips of fractures, while indirect injury was caused by displacing of the sempelvises. The direct injured arteries were iliolumbar artery, lateral sacral artery, obutator artery, superior gluteal artery, inferior gluteal artery. The indirect injured arteries were superior gluteal artery, inferior gluteal artery, internal pudendal artery, common iliac artery, internal iliac artery, external iliac artery. 3. The direct injury was associated with the place and degree of pelvic fractures, while indirect injury was associated with the displacing of hemipelvis and classification of pelvic fractures. During the management of the pelvic artery injury, we supposed that injured arteries should be embolized superselectively. 5. The pelvic anatomic characteristics were associated with the injured vessels. The superior gluteal artery, which passed through sacral nerve plexus and had a small angle out of the pelvis, was liable to be injured, while inferior gluteal artery, which had a bigger angle out of the pelvis, had a lower injured incidence. The pelvicligaments can protect the pelvic arteries from being injured.The locations of causing pelvic vessels: (1) Sacroiliac joint: At this place , the internal iliac arteries and veins through over each other, and are banded by nerves and ilium . The have small mobility. So when demi-pelvis displace, they easily are injured. (2) Anterior sacrum: Aacral fracture cause lateral sacral arteries and veins. (3 ) Greater sciatic notch: The superior gluteal vessels near the bone, and easily injured. (4) Superior rami of pubis: There are anastomosis of obturator vessels and inferior epigastric vessels, when pubic fracture , they are easily injured. 0 7.The pelvic vessels are injured which are caused often by type APC II ■> III and type VS fractures. Solitarius vessels injury are caused by local pelvic fracture.The pelvic arterial injury should be treated as follows: (1) When internal artery are injured, besides internal iliac artery, the deep iliac circumflex artery, communicating branch of external iliac artery and obturator artery, lateral sacral artery should be embolised . (2) When superior gluteal artery are injured, besides superior glutea artery, the superior gluteal artery, iliolumbatr arter should be embolised. 3 ) When iliolumbar artery are injured, besides iliolumbar artery, the deep iliac circumflex artery, superior gluteal artery should be embolised . (4) When lateral sacral artery are injured, besides lateral sacral artery, the other lateral sacral artery, medium sacral artery should be embolised .(5)When inferior gluteal artery are injured, besides inferior gluteal artery, the superior gluteal artery, internal pudendal artery, lateral femoral circumflex artery and obturator artery, lateral sacral artery should be embolised (6) When obturator artery are injured, besides obturator artery, communicating branch of external iliac artery and obturator artery should be embolised. The anterior sacral venous plexus, bladder venous plexus, posterior pubis venous plexus are easily injured when pelvic fractures. The ascending lumbar vein which through out lumbar nerve 4 and 5 is easily injured when sacral ala fracture. The anterior sacral venous plexus is easily injured when sacral fracture. The posterior pubis venous plexus are easily injured when pubic fractures.