Median Sacral Artery Research Articles

An extremely rare bifurcation pattern of the caudal abdominal aorta: case report demonstrated by angiography

An extremely rare bifurcation pattern at the caudal abdominal aorta was encountered on the pelvic angiography and MR angiography of a male patient. Instead of dividing into two common iliac arteries, the caudal abdominal aorta first gave the right external iliac artery at the level of the last lumbar arteries, then bifurcated into a right internal iliac artery and a left common iliac artery. The median sacral artery originated at this anomalous bifurcation. This high origin of the right external iliac artery and separate branching of these right iliac vessels from the abdominal aorta are important during the interventions in the region. We present the angiography findings and discuss the embryological origin of this unusual and unreported congenital anomaly.

Endovascular repair of an abdominal aortic aneurysm in a patient with horseshoe kidney demonstrating the nonend artery nature of an accessory isthmic artery

Horseshoe kidney is a rare congenital anomaly of the urinary system and a coexisting abdominal aortic aneurysm with a horseshoe kidney is associated with substantial surgical challenges. The horseshoe kidney has a variant arterial supply in the majority of patients with accessory renal arteries arising from the aorta or iliac arteries. These arteries are considered to be end arteries and renal tissue perfused with these vessels is under risk of infarction in case of compromise. Since the surgical approach is challenging and carries a high risk of complications, endovascular repair seems to be an attractive alternative when feasible. The purpose of this report is to describe our experience in the successful endovascular treatment of a patient who had the coexistence of an abdominal aortic aneurysm with a horseshoe kidney. The patient had an accessory isthmic artery which shared a common origin with the middle sacral artery which provided retrograde flow following stent-grafting. There was no loss of renal tissue following the intervention. This case demonstrates that accessory renal arteries in patients with horseshoe kidneys are not necessarily end arteries. Their careful analysis prior to the procedure is essential for rational therapy planning.

Anatomy of Spinal Cord Blood Supply in the Pig

In a species as popular in research as the pig, little information is available concerning the blood supply and vascular anatomy of the spinal cord and comparability to humans. To visualize vessels contributing to the blood supply of the spinal cord, x-ray digital subtraction angiography and vascular casting by injection of a polymerizing solution of methylmethacrylate were used. The pig has larger internal thoracic arteries and subscapular arteries than the human, providing extensive collateral flow to the lower body, which offers blood supply to the spinal cord through the collaterals. The pig has a fine-caliber vessel plexus providing blood to the neck area, from which flow will reach both the spinal cord and the base of the brain. The segmental thoracic and lumbar arteries are relatively small in pigs, and they almost all originate as a single branch from the aorta and divide after 3 to 4 mm. The segmental vessels show a clear diminution after 2 to 3 cm at the level of the vertebral bodies. Pigs show major differences in the anatomy of the aortic bifurcation compared with humans. The median sacral artery in pigs is a large-caliber vessel, of a size almost comparable to the common iliac artery, with an isolated single dorsal branch leading to the spinal cord. Documenting the anatomic differences in spinal cord blood supply between pigs and humans will aid in the planning of future experimental studies and in determining the clinical relevance of such studies.

Neurovascular risks of sacral screws with bicortical purchase: an anatomical study

The aim of this cadaver study is to define the anatomic structures on anterior sacrum, which are under the risk of injury during bicortical screw application to the S1 and S2 pedicles. Thirty formaldehyde-preserved human male cadavers were studied. Posterior midline incision was performed, and soft tissues and muscles were dissected from the posterior part of the lumbosacral region. A 6 mm pedicle screw was inserted between the superior facet of S1 and the S1 foramen. The entry point of the S2 pedicle screw was located between S1 and S2 foramina. S1 and S2 screws were placed on both right and the left sides of all cadavers. Then, all cadavers were turned into supine position. All abdominal and pelvic organs were moved away and carefully observed for any injury. The tips of the sacral screws were marked and the relations with the anatomic structures were defined. The position of the sacral screws relative to the middle and lateral sacral arteries and veins, and the sacral sympathetic trunk were measured. There was no injury to the visceral organs. In four cases, S1 screw tip was in direct contact with middle sacral artery. In two cases, S1 screw tip was in direct contact with middle sacral vein. It was observed that the S1 screw tips were in close proximity to sacral sympathetic trunk on both right and the left sides. The tip of the S2 screw was in contact with middle sacral artery on the left side only in one case. It is found that the tip of the S2 screw was closely located with the middle sacral vein in two cases. The tip of the S2 pedicle screw was in contact with the sacral sympathetic trunk in eight cases on the right side and seven cases on the left side. Lateral sacral vein was also observed to be disturbed by the S1 and S2 screws. As a conclusion, anterior cortical penetration during sacral screw insertion carries a risk of neurovascular injury. The risk of sacral sympathetic trunk and minor vascular structures together with the major neurovascular structures and viscera should be kept in mind.

Vascular anatomy of the presacral space in unembalmed female cadavers

The purpose of this study was to characterize the vascular anatomy of the female presacral space (PSS) and to correlate findings to the abdominal sacrocolpopexy. Detailed dissections of the PSS were performed in 52 unembalmed female cadavers. The closest cephalad vessel to the mid sacral promontory (MSP) was the left common iliac vein (LCIV), mean distance 27 mm (9-52 mm). The closest vessel lateral to MSP was also the LCIV, mean distance 22 mm (9-35 mm). The average distance of the middle sacral artery and vein to the MSP was 4 mm (0-15 mm) and 7 mm (0-17 mm), respectively. The mean distance of the sacral venous plexuses to the MSP was 34 mm (4-86 mm). Anatomic location of the vascular boundaries and contents of the PSS is highly variable. Careful dissection and exposure of the anterior longitudinal ligament of the sacrum before suture placement should minimize potentially life-threatening vascular complications.

Estimation of the functional role of arterial pathways to the buttock circulation during treadmill walking in patients with claudication

The aim of the study was to estimate the functional contribution of the arterial inflow pathways to the pelvic circulation during walking in patients with stage 2 lower extremity arterial disease. Transcutaneous oxygen pressure (Ptc(O(2))) changes during exercise can be used to estimate the severity of regional blood flow impairment while walking. Seventy patients with stable lower limb claudication were studied using a multivariate linear regression model. The relationship between exercise-induced buttock Ptc(O(2)) changes, the ipsilateral calf Ptc(O(2)) changes, and the arterial diameters of the pelvic arteriographic pathways were analyzed. The ipsilateral hypogastric and lumbar pathway, as well as the ipsilateral calf Ptc(O(2)) changes, were the only variables significantly related to buttock Ptc(O(2)) changes (r = 0.47; P < 0.001). Their normalized respective contribution to the regressive model was 39%, 19%, and 18%. None of the contralateral hypogastric, mesenteric, and sacral pathways or pathways stemming from the external iliac artery showed significant correlation to buttock Ptc(O(2)) changes. The ipsilateral hypogastric and ipsilateral lumbar pathways are the major pathways responsible for the functional buttock blood flow supply during walking. The role of contralateral hypogastric, inferior mesenteric, and median sacral pathways and arteries distal to the internal iliac trunk is negligible in the normal or compensatory blood flow supply. Distal Ptc(O(2)) decrease at exercise aggravates proximal Ptc(O(2)) decrease, possibly through the occurrence of a "steal phenomenon" of distal over proximal circulation during walking.

EFFECTS OF TAIL FAT ON HALOTHANE BIOTRANSFORMATION IN FAT-TAILED SHEEP

1. The aim of the present study was to evaluate the effects of tail fat on halothane biotransformation following similar anaesthetic exposure in intact sheep and sheep with a ligated median sacral artery. 2. A prospective randomized experimental study was performed using 12 healthy, 10-12-month-old female sheep. 3. Sheep were randomly divided into two groups of six animals each and were anaesthetized twice at 2 weekly intervals. After mask induction with halothane in 100% oxygen, sheep were intubated and anaesthesia was maintained for 3 h using a rebreathing system. Serum fluoride concentration (SFC) was measured at 0, 1, 3, 6, 12, 24, 48 and 72 h following the induction of anaesthesia. Serum biochemistry was also evaluated at baseline and 72 h after anaesthesia. Induction and extubation times and time to sternal recumbency were also recorded during anaesthetic induction and recovery. Prior to the second anaesthesia (2 weeks later), the median sacral artery (MSA) was ligated under epidural anaesthesia in the experimental group. Sheep in the control group underwent sham operation. All sheep were anaesthetized as before. 4. Following the first halothane anaesthesia, SFC was significantly increased from 3 to 48 h compared with baseline. In the second stage of the experiment, the increases in SFC in the control group were similar to those seen in the first stage of the experiment. However, in MSA-ligated sheep, the increases in SFC were only significant between 3 and 12 h compared with baseline. The SFC was significantly higher in intact sheep from 3 to 72 h compared with the MSA-ligated group. Extubation and sternal recumbency times were significantly longer in intact sheep. 5. Ligation of the MSA in fat-tailed sheep induced a significant reduction in SFC, suggesting that the presence of tail fat substantially affects halothane metabolism during the peri-anaesthetic period in sheep. The greater extent of halothane biotransformation may be clinically important in, otherwise normal, obese patients.

Three-Dimensional Computed Tomographic Anatomy of the Abdominal Great Vessels Pertinent to L4-L5 Anterior Lumbar Interbody Fusion

A recent accumulation of surgical and radiological literature has helped spine surgeons to better understand the anatomy and establish surgical trajectories to the anterior L4-L5 disc space. However, the preoperative display of anatomic data in individual subjects in the three-dimensional (3-D) mode has rarely been attempted. The objective of this study was to acquire 3-D images of the abdominal great vessels pertinent to the L4-L5 anterior lumbar interbody fusion (ALIF), and to better define the radiological vascular anatomy. The 3-D images of 100 subjects with non-spinal diseases, generated from abdominal computed tomography angiography (CTA), were analyzed retrospectively. The anatomy of the great vessels pertinent to the L4-L5 ALIF procedure was investigated by measuring the level of the abdominal aorta (AA) bifurcation and that of the inferior vena cava (IVC) confluence in relation to the lumbar vertebral body. These two complexes were segmented into upper or lower parts, or disc level. The visibility of the middle sacral artery (MSA) and the left L4 lumbar artery on the 3-D images was also assessed. The AA bifurcation level was above L4 in 4, at L4 in 55, at L4-L5 in 23, and at L5 in 18 subjects. The IVC confluence level was at L4 in 17, at L4-L5 in 14, at L5 in 68 and below L5 in 1 subject. Levels of the bifurcation of the AA/IVC as combined data showed that the AA bifurcation was usually located 1 - 2 segments above the IVC confluence. The MSA and L4 segmental artery were identified in 79 and 83 subjects, respectively. The 3-D images of the abdominal great vessels together with the lumbar spinal column were reliably depicted. Anatomic data obtained from this study are in accordance with those obtained from conventional 2-D studies, and the 3-D images can serve as a versatile tool for preoperative evaluation for the ALIF candidates and can contribute to the reduction of surgical time and perioperative vascular complications.

Consideration of the potential courses of the common iliac artery

We encountered a rare case of the left common iliac artery in a 92-year-old Japanese female cadaver during dissection practice for medical students. The artery entered into the small pelvis without branching to the external iliac artery. There, it went down slightly medially and then turned laterally and passed behind the first sacral nerve. The artery ran anterolaterally further and returned to the greater pelvis and became the external iliac artery, which continued to the femoral artery as usual. During the course in the small pelvis, the artery branched to give rise to each branch of the internal iliac artery. We speculate that in the present case, a communication between the median sacral artery and the superior gluteal artery, passing behind the first sacral nerve, enlarged and compensated the usual common iliac artery.

Vascular anatomy of the presacral space: A fresh tissue cadaver dissection

To assess variability in the vascular structures of the presacral space and to estimate the risk of injury because of blind suture placement during sacral colpopexy. Ten fresh frozen female cadavers were evaluated. Three 0-polyester sutures were placed blindly through the peritoneum and around the midline of the anterior longitudinal ligament. The presacral space was dissected and the sutures examined for injury to vessels. The midline of the anterior longitudinal ligament was marked from the promontory to its inferior edge, and measurements were taken to the leading edge of vessels proximal to the presacral space. On a template, all vessels larger than 2 mm were drawn to scale and overlaid on the template. Unequivocal vascular injury was found in 5 cadavers because of blind sutures. Four injuries occurred to the middle sacral artery and 1 to the left common iliac vein. There was significant variability in location of vessels, particularly on the left side of the ligament. The vascular pattern of the presacral space is variable, and major vessels may deviate significantly from their expected positions. Surgeons should carefully expose this space prior to placing sutures during sacral colpopexy.

MR aortography and serum cholesterol levels in patients with long-term nonspecific lower back pain.

A cross-sectional analysis of the feeding arteries of the lumbar spine and cholesterol levels on patients with long-term nonspecific lower back pain. To evaluate whether occlusion of lumbar and middle sacral arteries or serum cholesterol levels are associated with lower back pain and/or with disc degeneration. Atherosclerosis in the wall of the abdominal aorta usually develops at the ostia of branching arteries and the bifurcation, and may obliterate orifices of lumbar and middle sacral arteries. Obstruction of these arteries causes ischemia in the lumbar spine and may result in back symptoms and disc degeneration. MR aortography and cholesterol blood tests were performed on 51 patients with long-term lower back pain without specific findings (i.e., spinal or nerve root compression) in regular lumbar MR images. The patients ranged from 35 to 70 years of age (mean age, 56 years). Serum cholesterol and low-density lipoprotein (LDL) cholesterol levels were measured. To assess symptoms and disability NASS low back Outcome Instrument was used. Twenty-nine (78%) of 37 men and 11 (77%) of 14 women showed occluded lumbar and/or middle sacral arteries. The prevalence of occluded arteries was 2.5 times more than in subjects of corresponding age group in a Finnish necropsy material. Twenty-three (62%) men and seven (50%) women had significant disc degeneration. Disc degeneration was associated with occluded lumbar/middle sacral arteries (P = 0.035). Patients with occluded arteries or significant disc degeneration did not complain more severe symptoms than those without, whereas patients with above normal serum LDL cholesterol scored higher in neurogenic symptoms (P = 0.031) and complained more often severe pain (P = 0.049) than those with normal LDL cholesterol. The study indicates that lumbar and middle sacral arteries are often occluded in patients with nonspecific long-term lower back pain. Occlusion of these arteries may also be associated with disc degeneration.

Laparoscopic ligation of the median sacral artery before resection of a sacrococcygeal teratoma

To minimize the risk of exsanguinating hemorrhage, the authors describe a technique of laparoscopic ligation of the median sacral artery before posterior sagittal resection of type I sacrococcygeal teratoma (SCT). Two female infants with antenatally diagnosed SCT underwent postnatal evaluation and preoperative imaging and were taken to the operating room. In both patients, pneumoperitoneum was established via an epigastic 5-mm trocar. Two additional trocars were inserted in the right and left lower quadrants. The peritoneal reflection was opened to the right of the sigmoid colon, and the presacral space was explored. A large median sacral artery was identified easily, isolated, and divided. The children then were placed in a prone position, and the tumors underwent en bloc resection via a Chevron incision with minimal blood loss. The laparoscopic portion of the procedure was performed in an average of 15 minutes. This is the first report of laparoscopic ligation of the median sacral artery before posterior resection of a sacrococcygeal tumor in an infant. This technique can be performed easily with minimal morbidity. Division of this artery is a logical preventative measure and may reduce the risk of hemorrhage during operative resection.

Importance of extrasegmental vessels for spinal cord blood supply in a chronic porcine model.

Our purpose was to investigate the interaction of the important components of spinal cord blood supply in the pig model to enable its use for future studies of spinal cord protection. Twenty-five juvenile pigs (20-22 kg) underwent serial intercostal (IC) or lumbar artery (LA) ligation until disappearance of motor evoked potentials (MEPs). Pigs underwent sequential craniocaudal IC/LA ligation alone (n=5); following clamping of both subclavian arteries (n=4), or clamping of the median sacral artery (MSA, n=4). Animals also underwent serial caudocranial clamping of LA/IC alone (n=4); preceded by clamping of the subclavian arteries (n=4), or of the MSA (n=4). Results were verified by Tarlov's scores and perioperative angiography. All animals with MEP loss suffered postoperative paraplegia. Groups were equivalent with regard to stable arterial pressures (64.6+/-3.1 degrees C) throughout the experiment, temperature (36+/-1.1 degrees C) and other physiological parameters. Mean number of clamped IC/LA before MEP loss for cranio-caudal clamping direction was 12.8+/-0.8 for segmental arteries isolated, 9+/-0.8 if both subclavian arteries were ligated previously and only 4.3+/-0.5 IC if the median sacral artery was clamped before. Mean number of clamped LA for caudo-cranial clamping direction was 5.8+/-0.9 for segmental lumbar arteries, 5.5+/-0.6 LA if both subclavian arteries were ligated previously and 3.5+/-0.6 if the median sacral artery was clamped before. This study confirms the importance of lumbar and MSA arteries to cord viability. It documents the interaction of the subclavian and MSA (roughly equivalent to the hypogastric arteries in humans) with segmental vessels in providing spinal cord blood supply. It also provides the physiologic basis for use of the pig model for studies of spinal cord protection in aortic surgery.

PRESSURE ULCERS

Two articles on “Pressure Ulcers” appeared in JAMDA Nov./Dec. 2001. Both stressed that the actual etiology is obscure. Generally pressure is accepted as the cause. Shear 1 Reichel SM Shearing force as a factor in decubitus ulcers in paraplegics. JAMA. 1958; 166: 762-763 Crossref PubMed Scopus (118) Google Scholar or vascular occlusive disease 2 Webster RM Schermerhorn TJ Sacral decubiti, the median sacral artery, fluorescein, and acts of God. Br J Gen Pract. 2001; 51: 849 PubMed Google Scholar may be the etiology.

Concomitant conus medullaris arteriovenous malformation and sacral dural arteriovenous fistula of the filum terminale.

A patient with a spinal intradural arteriovenous malformation (AVM) at the conus medullaris concomitant with a sacral dural arteriovenous fistula (AVF) of the filum terminale is reported. A 44-year-old-male presentied with bilateral leg weakness and urinary incontinence for several months. Spinal angiography demonstrated two lesions: one was spinal intradural AVM at the conus medullaris supplied by the anterior spinal artery; the other was sacral dural AVF of the filum terminale supplied by the middle sacral artery. Although multifocal spinal cord AVMs have been reported, this is the first case report of two different types of vascular malformations coexisting in one patient. The arterial supply of the dural AVF of the filum by the middle sacral artery is also first demonstrated in the literature. The patient was treated successfully by surgical approach for both lesions in the same operation.

Von Recklinghausen病に合併した仙骨前神経鞘腫の1例

A 53-year-old woman admitted with presacral tumor confused initially with ovarian cystoma was diagnosed with von Recklinghausen's disease based on physical findings, and an elastic hard mass was palpable on the posterior wall of the rectum. CT scan and MRI showed a solid cystic tumor 7 cm in diameter in the presacral space. Angiography showed a hypervascular mass fed by the middle and left lateral sacral arteries. We suspected the tumor was a malignant peripheral nerve sheath tumor, and extirpated it. The specimen was a 8×6×5 cm yellowish solid cystic tumor weighing 130g. The histopathological diagnosis was schwannoma. Presacral schwannoma in a patient with von Recklinghausen's disease is quite rare, and has not, to our knowledge, been reported in the literature except for 1 case.

The vascular anatomy anterior to the L5-S1 disk space.

Dissection of 37 human cadavers was performed to assess the variability in the vascular anatomy anterior to the L5-S1 disc space. To determine the variability of the anterior vascular anatomy at the L5-S1 disc space, and to assess its reliability as an anatomic landmark for the placement of anterior interbody fusion devices. Although multiple studies have defined both the lumbar spinal anatomy and the anatomy of the great vessels, the relation of the great vessels to the anterior L5-S1 disc space has not been quantified directly. This study investigated 35 human cadavers (17 males and 18 females). The anterior L5-S1 disc space and great vessel bifurcation were exposed through a transabdominal approach. Two independent observers each obtained 10 measurements in each specimen. The middle sacral artery was present in 100% of the specimens, averaging 2.5 mm in width. Its location in relation to the midline was quite variable, with a range greater than 2 cm in both the top and bottom of the disc. The distance from the bifurcation to the top of the L5-S1 disc averaged 18 mm (range, 7-36 mm). The total width between the left common iliac vein and the right common iliac artery averaged 33.5 mm (range, 12-50 mm). The middle sacral artery, present in 100% of the specimens, is a poor anatomic landmark for locating the midline at L5-S1. Because the average space available between the left common iliac vein and the right common iliac artery is 33.5 mm, and because the left common iliac vein averages only 12 mm from midline, the surgeon must be prepared to mobilize the local vasculature in most cases to expose the L5-S1 disc space adequately.

Anomalous Intercostal Arterial Trunk

Anomalous Intercostal Arterial Trunk

Endoleaks after endovascular repair of aortic aneurysm: are they predictable?-initial results.

To evaluate the predictability of endoleak. Thirteen women and 60 men (mean age, 69.8 years) underwent transfemoral insertion of endoluminal stent-grafts for treatment of aortic aneurysms. Follow-up included helical computed tomography (CT) at 3-month intervals. In the cases of endoleak, angiography also was performed to document the number of leak sites, their size and position, the feeding artery, the size of the aneurysm, the amount of thrombus, and the visualization of the lumbar arteries and inferior mesenteric artery. These data were correlated (Student t test) with the probability of endoleak. A total of seven (10%) endoleaks were identified at CT in 68 patients. The feeding vessels were lumbar arteries in three cases, the inferior mesenteric artery in three cases, and the median sacral artery in one case. Of all factors, only the number of lumbar arteries visualized preoperatively (P <.005) had a significant correlation with probability of endoleak. In 71% (five of seven patients) of the cases of lumbar endoleak, four lumbar arteries were patent, whereas among the 61 patients with successfully repaired aneurysm, only eight (13%) had four patent lumbar arteries. Endoleaks were never found in the primarily thrombosed sections of an aneurysm. Prediction of endoleaks with absolute certainty remains elusive. The single correlating risk factor identified from the data was patency of four or more lumbar arteries visualized preoperatively at CT.

Treatment of leaks after endovascular repair of aortic aneurysms.

To evaluate leaks after the endovascular repair of aortic aneurysms and treat them with occlusive therapy. Seventy patients (11 women, 59 men), aged 26-82 years (mean, 69.2 years), underwent transfemoral insertion of endoluminal stent-grafts for treatment of aortic aneurysms. Indications were traumatic pseudoaneurysms (n = 5) or arteriosclerotic aneurysms (n = 65). Aneurysms were thoracic (n = 5) or infrarenal (n = 65). To exclude the possibility of leaks, spiral computed tomography (CT) was performed at 3-month intervals. Patients with leaks that persisted unchanged longer than 3 months were referred for angiography and occlusive therapy. At CT, 21 leaks were identified in 17 of 70 patients (24%). Only 11 of those 17 patients (65%) had leaks identified with conventional aortography. Selective angiography, however, depicted all of these. Eighteen of 21 leaks proved amenable to occlusive treatment: surgery (n = 1), further stent implantation (n = 4), or embolization (n = 13). In one leak, spontaneous occlusion occurred after 3 months. Two leaks in either the iliolumbar or the median sacral artery were inaccessible; one remained untreated, and the other was unsuccessfully treated. Mean follow-up of occlusive therapy was 6.8 months (range, 2-14 months). Successful occlusion of perigraft leaks is feasible in most cases and can be performed without major complications.