Vascular anatomy of the spinal epidural space: Considerations on the etiology of the spontaneous spinal epidural hematoma

The anatomy of the blood vessels in the spinal epidural space is an important basis for the understanding of the etiology of the spontaneous spinal epidural hemorrhage (SSEH). The structure of the internal vertebral venous plexus and epidural arteries, in particular the poorly recognised “cluster-type” arteries, has been studied. The cluster arteries are easily mistaken for vascular anomalies. The literature is reviewed, and the different theories on the etiology of the SSEH are discussed.     

颈内静脉的静脉丛引流模式及影响因素

目的　探讨颈内静脉的主要静脉丛引流模式以及相关因素。 方法　根据160例脑血管病患者DSA图像资料，分析动脉造影的静脉期成像。将颈内静脉的主要静脉丛分为前路引流模式（翼静脉丛）及后路引流模式，后路引流模式分为丛状引流（椎旁静脉丛）和孤立静脉引流（以颈深部静脉为主）。后路丛状引流再分为2组：椎旁静脉丛伴或不伴明显颈深部静脉引流。根据临床资料及相关危险疾病，应用卡方检验分析颈内静脉主要静脉丛引流模式的影响因素。 结果　双侧颈内动脉造影显示160例病人共320侧颈内静脉，其中19.7%（63侧）为翼静脉丛引流，16.9%（54侧）为椎旁静脉丛伴有明显颈深部静脉引流，15.6%（50侧）为椎旁静脉丛伴无明显颈深部静脉引流，10侧（3.1%）为颈深部静脉引流，5.7%（13侧）为前、后丛联合引流。χ2检验发现，年龄、伴颈内静脉异常（发育不全、狭窄、闭塞）、伴颈内静脉压迹、合并高血压病是影响颈内静脉静脉丛引流模式的独立危险因素。 结论　颈内静脉的静脉丛引流模式，以后路椎旁静脉丛引流为主，引流模式可因相关因素而改变，这对评估颅底、颈部手术及神经介入治疗具有重要价值。     

颅内外沟通性静脉通道的研究进展

目的 总结颅内外沟通性静脉主要通道的结构功能和临床意义的相关研究进展。方法 以“vertebral venous plexus”“pterygoid venous plexus”“emissary vein”“diploic venous”“extracranial venous outflow”以及“椎静脉丛”“翼丛”“导静脉”“板障静脉”“颅外静脉引流”为关键词,在PubMed、Web of Science、中国知网、万方数据等数据库中检索1957年1月-2019年1月国内外有关颅内外沟通性静脉通道研究的文献,对该通道主要的结构功能及临床意义进行总结分析。结果 共检索到文献518篇,按纳入标准和排除标准,最终纳入35篇英文文献。导静脉、板障静脉、静脉丛相互沟通并与颅内静脉窦沟通,形成颅内颅外静脉广泛的吻合交通。利用MR、CT等成像技术可明确病变与这些颅内外沟通性静脉通道之间的解剖关系,这对经鼻内镜颅底手术及神经介入手术具有重要价值。这些静脉通道还参与了颅内压调节,并可能与多发性硬化、老年痴呆等神经系统疾病有关。结论 了解颅内外静脉主要通道的结构功能及其与颅内病灶之间的关系,对于经鼻内镜颅底手术及神经介入治疗具有重要价值。颅内外静脉通道相对于颅内外动脉通道要复杂得多,其生理及血流动力学特点还需要进一步研究。     

The vertebral venous plexuses: the internal veins are muscular and external veins have valves

The internal and external vertebral venous plexuses (VVP) extend the length of the vertebral column. Authoritative sources state that these veins are devoid of valves, permitting bidirectional blood flow and facilitating the hematogenous spread of malignant tumors that have venous connections with these plexuses. The aim of this investigation was to identify morphologic features that might influence blood flow in the VVP. The VVP of 12 adult cadavers (seven female, mean age 79.5 years) were examined by macro- and micro-dissection and representative veins removed for histology and immunohistochemistry (smooth muscle antibody staining). A total of 26, mostly bicuspid, valves were identified in 19 of 56 veins (34%) from the external VVP, all orientated to promote blood flow towards the internal VVP. The internal VVP was characterized by four main longitudinal channels with transverse interconnections; the maximum caliber of the longitudinal anterior internal VVP veins was significantly greater than their posterior counterparts (P < 0.001). The luminal architecture of the internal VVP veins was striking, consisting of numerous bridging trabeculae (cords, thin membranes and thick bridges) predominantly within the longitudinal venous channels. Trabeculae were composed of collagen and smooth muscle and also contained numerous small arteries and nerve fibers. A similar internal venous trabecular meshwork is known to exist within the dural venous sinuses of the skull. It may serve to prevent venous overdistension or collapse, to regulate the direction and velocity of venous blood flow, or is possibly involved in thermoregulation or other homeostatic processes.     

Postoperative spinal epidural hematoma: risk factor and clinical outcome

We report a series of epidural hematomas which cause neurologic deterioration after spinal surgery, and have taken risk factors and prognostic factors into consideration. We retrospectively reviewed the database of 3720 cases of spine operation in a single institute over 7 years (1998 April- 2005 July). Nine patients who demonstrated neurologic deterioration after surgery and required surgical decompression were identified. Factors postulated to increase the postoperative epidural hematoma and to improve neurologic outcome were investigated. The incidence of postoperative epidural hematoma was 0.24%. Operation sites were cervical 3 cases, thoracic 2 cases, and lumbar 4 cases. Their original diagnoses were tumor 3 cases, cervical stenosis 2 cases, lumbar stenosis 3 cases and herniated lumbar disc 1 case. The symptoms of epidural hematomas were neurologic deterioration and pain. After decompression, clinical outcome revealed complete recovery in 3 cases (33.3%), incomplete recovery in 5 cases (55.6%) and no change in 1 case (11.1%). Factors increasing the risk of postoperative epidural hematoma were coagulopathy from medical illness or anticoagulation therapy (4 cases, 44.4%) and highly vascularized tumor (3 cases, 33.3%). The time interval to evacuation of complete recovery group (29.3 hours) was shorter than incomplete recovery group (66.3 hours). Patients with coagulopathy and highly vascularized tumor were more vulnerable to spinal epidural hematoma. The postoperative outcome was related to the preoperative neurological deficit and the time interval to the decompression.     

Variants in the structure and topography of the superior margin of the epidural space of the human spinal cord

Variants in the structure of the upper margin of theepidural space at sites of transition from the dura mater of the spinal cord to the dura mater of the brain were studied. Stereoepidurographic (88 observations) and corrosion studies (49 observations) identified four levels for the position of the upper margin of the anterior section (intracranially located, lower edge of the occipital bone, bodies of C₁ and C₂) along with five levels for the posterior section (occipital bone, occipital bone-arch of C₁, C₁, C₁–C₂, C₂) of the epidural space. Variants on the shape of the upper margin of the anterior (falciform, oval, and dentate in the frontal plane; pointed, flexed spurs, pointed slits, and olive-shaped in the sagittal plane) and posterior (collar-shaped, oval, and bidentate forks with prongs of equal length and forks with prongs of unequal lengths) sections of the epidural space arose as a result of asymmetry in the attachment of the upper sections of the sac of the dura mater of the spinal cord to the walls of the vertebral canal. Weak areas of the upper wall of the epidural space (sites of transition from the dura mater of the spinal cord to the dura mater of the brain, paravasal capsule of the vertebral artery, the area of the first intervertebral foramen) were seen. __________ Translated from Morfologiya, Vol. 132, No. 5, pp. 38–42, September–October, 2007.     

The role of cutaneous afferents in controlling locomotion evoked by epidural stimulation of the spinal cord in decerebrate cats

The effects of the cutaneous input on the formation of the locomotor pattern in conditions of epidural stimulation of the spinal cord in decerebrate cats were studied. Locomotor activity was induced by rhythmic stimulation of the dorsal surface of spinal cord segments L4-L5 at a frequency of 3-5 Hz. Electromyograms (EMG) recorded from the antagonist muscles quadriceps, semitendinosus, tibialis anterior, and gastrocnemius lateralis were recorded, along with the kinematics of stepping movements during locomotion on a moving treadmill and reflex responses to single stimuli. Changes in the pattern of reactions observed before and after exclusion of cutaneous receptors (infiltration of lidocaine solution at the base of the paw or irrigation of the paw pads with chlorothane solution) were assessed. This treatment led to impairment of the locomotor cycle: the paw was placed with the rear surface downward and was dragged along in the swing phase, and the duration of the stance phase decreased. Exclusion of cutaneous afferents suppressed the polysynaptic activity of the extensor muscles and the distal flexor muscle of the ipsilateral hindlimb during locomotion evoked by epidural stimulation of the spinal cord. The effects of exclusion of cutaneous afferents on the monosynaptic component of the EMG response were insignificant.     

Case report and mini literature review: anesthetic management for severe peripartum cardiomyopathy complicated with preeclampsia using sufetanil in combined spinal epidural anesthesia

Peripartum cardiomyopathy (PPCM) is a rare entity, and anesthetic management for cesarean section of a patient with this condition can be challenging. We hereby present the anesthetic management of a patient with PPCM complicated with preeclampsia scheduled for cesarean section, along with a mini review of literature. A 24 year-old primigravida with twin gestation was admitted to our hospital with severe PPCM and preeclampsia for peripartum care, which finally required a cesarean section. Preoperative optimization was done according to the goal of managing left ventricular failure. Combined spinal epidural (CSE) anaesthesia with bupivacaine and sufentanil was used for cesarean section under optimal monitoring. The surgery was completed without event or complication. Postoperative pain relief was adequate and patient required only one epidural top up with sufentanil 6 hours after operation. To the best of our knowledge there is no report in literature of the use of sufentanil as a neuraxial opioid in the anesthetic management of cesarean section in a patient with PPCM. CSE with sufentanil may be a safer and more effective alternative in such cases.     

Spatial correlation between sensory regions and the drainage fields of pial veins in rat cerebral cortex

Summary Visual and somatosensory evoked potentials were mapped in the cerebral cortex of adult rats and, after filling the cerebral arteries and veins with dye, the mappings were then compared to the distribution of pial veins. A close relationship was found between the position, size and shape of the occipital venous drainage field and the distribution of visual evoked potentials with high amplitudes and short latencies. Accordingly, such potentials evoked by stimulation of the forepaw and the tailroot were confined to the fronto-parietal drainage field. In the case of individual variations in the expansion and shape of sensory areas, the medial and lateral borders of the occipital drainage field and the medial border of the fronto-parietal drainage field covaried. Only at the common border between these two drainage fields, visual evoked potentials with small amplitudes and long latencies extended into the parietal drainage field and overlapped with somatosensory evoked potentials. This overlapping area corresponds in position to the anterior part of the peristriate cortex. A comparison between the vascular organization and cytoarchitectonic maps of the rat cortex indicates that other parts of the characteristic pattern of venous drainage fields may also correlate with the cytoarchitectonic and functional organization of the cerebral cortex. These observations suggest that during morphogenesis the formation of sensory projections to the cerebral cortex may interact with the angiogenesis, mainly with the development of veins.Fellow of the Alexander von Humboldt Stiftung     

Course of the short gastric veins and their suitability for pancreatic islet transplantation

Experience is being gained with pancreatectomy for patients with chronic pancreatitis suffering intractable pain. Transplantation of pancreatic islets isolated from the patient's own pancreas reduces the amount of injected insulin required, and research aims to develop treatments to make such patients independent of administered insulin. Claims have been made that the uppermost short gastric vein runs directly to the upper pole of the spleen in about 90% of subjects and that infusion of pancreatic islets by this route would allow them to settle in the spleen. This study investigates these claims. The findings suggest that the short gastric veins are inappropriate as a route of islet administration. Most short gastric veins, including the most superior, drain to tributaries of the splenic vein. Short gastric veins passing to the spleen itself without extra-splenic connections to the splenic vein and its tributaries are relatively rare. Only four examples in 12 specimens were found, and only two of these were the most superior short gastric vein. The short gastric veins run in the fat of the gastrosplenic ligament and are most readily visible as they leave the stomach. In our 12 dissecting room specimens, the short gastric veins ranged in number from 3-17, and in diameter from 0.5-4.5 mm (mean = 1.7 mm; SD = 0.7 mm). The four short gastric veins that drained directly to the spleen ranged in diameter from 0.5-1 mm, significantly narrower than those draining to the splenic vein or its tributaries and small for cannulation.     

光纤硬膜外导管优化与硬膜外腔解剖生理的探讨

目的探讨光纤硬膜外导管下硬膜外腔的解剖生理学特点,分析光纤硬膜外导管下置管较盲探下置管的技术优势。方法选择研究我院2013年1月至11月收治的60例需要进行硬膜外麻醉腹部手术患者资料,麻醉时分别采用普通导管(30例)与光纤硬膜外导管(30例),观察患者的麻醉和硬膜外腔的解剖结构特点。结果患者在插管后5 min、切皮时的HR、SPB和MAP与同组麻醉前、诱导前、插管前及观察组比较,差异具有统计学意义(P0.05)。硬膜外腔与椎管骨膜之间形成1个腔隙,这个腔隙并不与颅腔联通,但是含有一定的结缔组织和静脉丛,腔体容积一般能够达到100 m L左右,其前部与侧方不宽,而后部宽度较大,从颈部开始逐步扩大到腰部之后达到顶峰,而后逐步缩窄,一直到骶裂孔。结论光纤硬膜外导管可使患者的解剖生理结构更加清晰呈现,使麻醉医生从盲目置管达到明视置管。     

荧光显微镜观察封闭式脊髓窗内的大鼠脊髓微循环

目的 探讨应用荧光显微镜通过改进的封闭式脊髓窗,观察大鼠脊髓背侧软脊膜微循环状态的可行性及效果.方法 用8周龄雄性SD大鼠,暴露T9至T11棘突,咬除T10棘突和椎板,暴露硬脊膜;在T9和T11棘突上安装固定器辅助物.用牙科丙烯酸树脂和玻璃片为原料在T10节段安装改进的封闭脊髓窗.采血并离心(2 000 ×g)收集红细胞,将100 μL压积的红细胞用Dil荧光染料(5 mg/L)体外孵育,静脉注射人体内;用罗丹明6G(0.3 g/L)静脉注射,体内标记白细胞.大鼠脊柱用微循环观测椎体固定器进行固定.用动物活体荧光成像显微系统进行观测和记录.结果 通过该系统可以观测大鼠软脊膜上微血管的形态和分布特点、血管密度;可以观测到Dil标记的红细胞在血管内的黏附和流速,观察和记录罗丹明6G标记的白细胞在血管壁的黏附滚动.结论 改进式的封闭脊髓窗和微循环观测椎体固定器,可用于对大鼠软脊膜上微血管进行观察和检测.     

Lymphatico-venous anastomosis after obstruction of abdominal lymphatics and lymphatic drainage of the prostate in canines

The communication between abdominal lymphatics and the vertebral venous system in canines was observed under conditions of lymphatic obstruction. After obstructing lymphatics of the lumbar trunks, lipiodol was injected into the pedal lymphatics and visualized to enter the inferior vena cava 10 days later, and the vertebral venous system 12 days later by fluoroscopy. Radiographs of the transverse sectioned vertebrae showed that the contrast medium flowed from the para-aortic lymph nodes into the vertebral venous system and entered the vessels around the vertebrae and in the spinal canal, and the vertebral body at the ventral surface of lumbar vertebra. Histologically, the contrast medium was identified in the Haversian canal and peripheral region of the bone marrow. These results suggest that prostate cancer may metastasize the vertebral bone through the lymphatico-venous anastomosis and vertebral venous system. © 1993 Wiley-Liss, Inc.     

股骨头颈骨内、外静脉回流的解剖学研究

目的 :为探讨Legg Perthes病的发病机理及临床治疗提供形态学依据。 方法 :采用巨微解剖、血管透明、组织切片、造影、扫描电镜等方法对 45例胎儿、新生儿及儿童的股骨头颈骨内、外静脉回流途径、骨内微血管构筑特点进行观察。结果 :(1 )髋关节骨外静脉包括 :旋股内、外侧静脉 ,闭孔静脉 ,臀上、下静脉 ,颈后静脉 ,髂腰静脉 ,股骨头韧带静脉 ,颈升静脉 ;骨内静脉包括 :前、后、上、下骺静脉 ,内骺静脉 ,前、后、上、下干骺静脉。关节囊内存在丰富的滑膜下静脉网 ,髋关节周围形成两个彼此有吻合的环状结构。(2 )一条微动脉一般有两条微静脉伴行 ,微静脉间有丰富的横行吻合支 ,在微动脉移行为毛细血管的部位 ,常可见到环形缩窄。结论 :(1 )Legg Perthes病与股骨头、颈静脉回流障碍密切相关。 (2 )根据股骨头、颈骨内外静脉回流特点 ,Legg Perthes病可以设计骨内、外双重介入治疗 ,骨内、囊内静脉搭桥的显微外科治疗方案     

Anatomical variations in the pattern of the right hepatic veins: possibilities for type classification

A morphological study of the right hepatic veins (RHVv) was conducted based on the shape and the confluence pattern of the superior right hepatic vein (SRHV) and the presence of accessory right hepatic veins. The study was performed in 110 undamaged, randomly selected, cadaveric human livers prepared using the corrosion cast methodology. The principles for classifying the RHVv into types were as follows: the length of the vein trunk, the confluence of 2 or 3 main tributaries that form a trunk, and the accessory right hepatic veins that modify the venous drainage of the right side of the liver. Four types of SRHV were identified. Type 1 (20%), type 2 (40%) and type 3 (25%) were the most common, while type 4 (15%) was linked to the accessory right hepatic veins in cases where they drain a surgically important part of the liver. Accessory right hepatic veins were found in a total of 31 casts (28%). The hepatocaval confluence was studied and the tributary-free part of the SRHV trunk before it entered the inferior vena cava was measured. The tributary-free part of the SRHV was longer than 1 cm in 77% of the casts. Anastomoses between the terminal tributaries of the veins involved in the drainage of the right side of the liver were also investigated.