The relation between the lumbar vertebrae and the spinal nerves for far lateral lumbar spinal approaches.

The far lateral approaches to the lumbar spine require accurate knowledge of regional anatomy. The aim of this study is to evaluate the course of the lumbar nerve roots and their relation to important bony landmarks. Seven adult male cadavers fixed with formaldehyde were used. Morphometric parameters, including the lumbar nerve root diameters, the angle between the nerve roots and the midline, the transverse process length, the inter-transverse process height and width, and the relation between the nerve roots and the transverse processes of the caudal vertebrae were measured. It was observed that the diameter of the nerve roots, and the angle between the nerve roots and the midline, and the distance between the nerve roots and the lateral edge of the superior articular process increased gradually from L1 to L5. The diameter of the nerve root was 4.9+/-0.5mm for L1 and 7.5+/-1.0mm for L5. The midline nerve root angle was 36.1+/-1.6 degrees mm for L1 and 40.4+/-1.4 degrees mm for L5. The distance between the nerve root and the lateral edge of the superior articular process was 6.5+/-1.0mm for L1 and 11.4+/-1.6mm for L5. The nerve roots crossed the transverse processes of the caudal lumbar vertebrae. The nerve roots of L1 and L2 crossed the transverse processes in their first two quarters, the L3 nerve root crossed the transverse process in its second, third or fourth quarters, and the L4 nerve roots crossed the L5 transverse process in its third and fourth quarter or even external to it. Descending toward the lower lumbar vertebrae, the diameter of the lumbar nerve root increases and the nerve roots exit the intervertebral foramen with a larger angle. The special relation between the nerve roots and the caudal vertebra transverse process should be remembered during far lateral lumbar spine approaches.     

Pedicular and Extrapedicular Morphometric Analysis in the Korean Population : Computed Tomographic Assessment Relevance to Pedicle and Extrapedicle Screw Fixation in the Thoracic Spine

Objective

To evaluate the anatomical parameters that must be considered when performing thoracic transpedicular or extrapedicular screw fixation.

Methods

We selected 958 vertebrae (1,916 pedicles) from 98 patients for analysis. Eight parameters were measured from CT scans : the transverse outer pedicular diameter, transverse inner pedicular diameter, length, angle, chord length of the pedicles and the transverse width, angle, and chord length of the pedicle-rib units.

Results

The age of the patients ranged from 21 to 82 years (mean : 48.2 years) and there were 57 men and 41 women. The narrowest transverse outer pedicular diameter was at T5 (4.4 mm). The narrowest pedicle length was at T1 (15.9 mm). For pedicle angle, T1 was 31.6 degrees, which was the most convergent angle, and it showed the tendency of the lower the level, the lesser the convergent angle. The chord length showed a horizontal pattern with similar values at all levels. For the PRU width, T5 showed a similar pattern to the pedicle width at 13.4 mm. For the PRU angle, T1 was the largest angle at 46.2 degrees and the tendency was the lower the level, the narrower the angle. For chord length, T1 was the shortest at 46.9 mm and T8 was the longest at 60.1 mm.

Conclusion

When transpedicular screw fixations carried out at the mid-thoracic level, special care must be taken because there is a high chance of danger of medial wall violation. In these circumstances, extrapedicular screw fixation may be considered as an alternative treatment.     

Wallis动态稳定系统置入治疗腰椎失稳症的效果

背景：为保证可控制范围内的脊柱运动,改变失稳节段运动的负荷模式,并限制其异常活动,同时避免相邻节段椎间盘退变的发生,多种后路腰椎非融合固定装置被研发并用于临床。 目的：探讨Wallis动态稳定系统治疗腰椎失稳症的临床效果。 方法：选择中山大学附属第一医院脊柱外科收治的腰椎失稳症患者10例,男3例,女7例,年龄43~65岁,其中失稳节段1例为L1/2和L4/5,1例为L2/3,1例为L3/4,其余均为L4/5;合并相同节段腰椎间盘突出症2例,腰椎管狭窄症7例,相邻节段腰椎管狭窄症3例;失稳节段均行后路椎管减压、Wallis置入固定治疗。观察治疗前后视觉模拟VAS评分、下腰痛JOA评分、Oswestry功能障碍指数变化;失稳节段和相邻节段的活动范围及L4/5节段椎间盘后高度的变化。 结果与结论：10例患者均获得随访,随访时间2~13个月,平均9.2个月。手术时间平均128 min(90~185 min),术中平均出血量264 mL (50~600 mL)。腰痛均消失,术后患者的症状和体征均有明显改善;1例置入治疗后3个月因L4/5右侧腰椎管狭窄症复发,再行开窗减压术后症状消失。治疗后VAS评分较术前显著降低(P=0.003);JOA评分较术前显著增加(P=0.002),ODI评分较术前显著降低(P=0.008)。术后L4/5节段的活动范围与术前相比明显减少(P < 0.05),而术后相邻节段L3/4、L5/S1的活动范围与术前相比差异无显著性意义(P > 0.05)。提示Wallis动态稳定系统置入治疗腰椎失稳症能够取得比较满意的临床效果。     

腰椎退行性变对腰丛神经根及通道影响的尸体解剖研究

目的探讨腰椎退行性变对腰丛神经根及通道的影响。方法选取18例中老年尸体为对象,分析腰椎退行性变对腰丛神经根及通道的影响。结果椎间盘、椎间关节及黄韧带的退变常会导致黄韧带的间距变短,导致L4~5脊神经节和椎间静脉下支神经受到椎间管的压迫,L5及S1神经根中的硬膜囊外部分受到盘带间的压迫,而盘带间变窄还会致椎管变窄,导致人体最外侧的腰丛神经根受到影响。结论如果腰椎出现退行性变,患者的腰丛神经根通道将会受到明显影响。     

成人颈椎椎弓根螺钉在儿童腰椎应用的可行性*

背景：由于1~3岁幼年儿童椎体发育未完全成熟,各种解剖径线相对较成人小得多,尚无幼儿专用的椎弓根螺钉固定器械,现有能够利用的直径最小的椎弓根螺钉是用于成人颈椎侧块或椎弓根固定的钉棒系统。 目的：观察将成人颈椎椎弓根螺钉应用到成年猪颈椎与幼猪腰椎固定后的生物力学对比。 方法：将6具完整新鲜成年猪颈段C3~C6脊椎标本和6具完整8周龄新鲜幼猪腰段脊柱标本自椎间盘及关节处离断,游离成单个椎体,共54个椎体108侧椎弓根。按照标准操作将成人颈椎椎弓根螺钉分别安置在成年猪颈椎标本和幼猪腰椎标本的椎弓根上,应用生物力学方法测试螺钉的最大轴向拔出力。 结果与结论：颈椎标本最大轴向拔出力高于腰椎标本,但差异无显著性意义(P > 0.05);L1椎弓根螺钉的拔出力均值明显小于L3椎弓根螺钉的拔出力均值(P < 0.05);C5椎弓根螺钉的拔出力均值明显大于C3椎弓根螺钉的拔出力均值(P < 0.05);颈椎和腰椎标的骨密度差异有显著性意义(P < 0.01),椎体椎弓根力学数值与椎体骨密度之间存在线性正相关。说明取得了成人颈椎椎弓根螺钉在轴向拉力方面适应于幼儿腰椎的初步实验依据。     

后路及单侧椎间孔和前路腰椎椎体间融合并置入椎弓根螺钉后相邻节段的生物力学变化

目的：比较经后路、单侧椎间孔、前路腰椎椎体间融合及附加椎弓根螺钉后相邻节段的力学性能。 方法：新鲜的雄性小牛L1~L5节段脊柱标本15具。随机取5只标本作为正常对照组,在非破坏状况下测试其力学指标后,再将15只标本随机分为3组,按要求制作L4/5前路椭圆形碳纤维Cage 1枚融合（前路腰椎椎体间融合组）、后路长方体碳纤维椎间Cage 2枚融合（后路腰椎椎体间融合组）和侧方椎间钛合金Cage 1枚融合（单侧椎间孔腰椎椎体间融合组）模型。测试完成后,每个标本附加L4/5节段双侧Moss-miamiTM椎弓根螺钉测试。 结果：3种融合方法在附加内固定前后应变和位移都高于正常对照组,强度低于正常对照组（P<0.01）,3组间以单侧椎间孔腰椎椎体间融合组变化最大,后路腰椎椎体间融合组最小（P<0.05）;在内固定前后配对比较,附加内固定后各组应变、位移增加,强度降低（P<0.05）。 结论：3种融合方法在附加内固定前后都有加速上位相邻节段退变的趋势,附加内固定比单纯融合更易导致相邻节段退变,单侧椎间孔腰椎椎体间融合退变趋势更加明显,后路腰椎椎体间融合的趋势相对较小。     

双侧钉棒及同侧单钉棒置入内固定的生物力学比较

背景：腰椎失稳、腰椎滑脱等腰椎退行性疾病常常需要实施腰椎融合,其目标是稳定脊柱,但究竟采取何种内固定方式仍存在争论。 目的：比较单侧与双侧经椎间孔减压椎体间融合治疗腰椎退行性病变的生物力学差异。 方法：人新鲜尸体腰椎标本6具,L4~5模拟微创经椎间孔减压椎体间融合,根据不同的内固定组合方式分为2组,即双侧钉棒组及同侧单钉棒组。在生物力学试验机上测量各种固定方式不同工况下的运动范围(ROM值),并进行比较。 结果与结论：以完整的腰椎运动单元为参照,两固定组的ROM值均低于对照组(P < 0.05)。其中双侧钉棒组在各工况下ROM值均显著低于同侧单钉棒组(P < 0.05)。提示在生物力学实验中,单侧椎弓根螺钉固定椎间融合生物力学性能优良,刚度适中,腰椎可获得可靠的稳定性。但与双侧钉棒固定比较,单钉棒方式仍然存在差距。     

腰骶部脊神经后根的解剖与临床应用

目的从解剖和临床两方面探讨腰骶部脊神经后根的穿刺径路。方法对10具成人尸体腰骶部脊神经后根进行解剖学研究；根据解剖学研究结果对30例腰腿痛病人X-线及CT图片所示椎骨、硬膜囊与神经后根进行测量并分析，寻找一条安全穿刺脊神经后根的路径。结果尸体标本示脊神经前、后根分别位于马尾前、后部，后根较前根粗大，出硬脊膜后下行一段距离再出椎间孔，L3,4、L4,5、L5S1椎间隙的硬膜囊直径小于相应节段椎板间隙间距，且越低位者差距越大。病人测得的数据与标本相似，临床上从椎板间隙最宽处穿刺进针均能抵达相应的脊神经后根。结论经椎板间隙最宽处穿刺人路可抵达相应脊神经后根而不伤及硬膜囊。     

Pedicle Morphometry for Thoracic Screw Fixation in Ethnic Koreans : Radiological Assessment Using Computed Tomographic Myelography

Objective

In the thoracic spine, insertion of a pedicle screw is annoying due to small pedicle size and wide morphological variation between different levels of the spine and between individuals. The aim of our study was to analyze radiologic parameters of the pedicle morphometry from T1 to T8 using computed tomographic myelography (CTM) in Korean population.

Methods

For evaluation of the thoracic pedicle morphometry, the authors prospectively analyzed a consecutive series of 26 patients with stable thoracic spines. With the consent of patients, thoracic CTM were performed, from T1 to T8. We calculated the transverse outer diameters and the transverse angles of the pedicle, distance from the cord to the inner cortical wall of the pedicle, and distance from the cord to the dura.

Results

Transverse outer pedicle diameter was widest at T1 (7.66 ± 2.14 mm) and narrowest at T4 (4.38 ± 1.55 mm). Transverse pedicle angle was widest at T1 (30.2 ± 12.0°) and it became less than 9.0° below T6 level. Theoretical safety zone of the medial perforation of the pedicle screw, namely, distance from the cord to inner cortical wall of the pedicle was more than 4.5 mm.

Conclusion

Based on this study, we suggest that the current pedicle screw system is not always suitable for Korean patients. Computed tomography is required before performing a transpedicular screw fixation at the thoracic levels.     

An in vivo preparation for investigating neural responses to controlled loading of a lumbar vertebra in the anesthetized cat.

This paper describes a method for applying controlled loads to a lumbar vertebra while recording in vivo from primary afferents innervating the lumbar paraspinal tissues. Unlike the appendicular skeleton, the vertebral column poses a unique challenge for neurophysiological investigations. Distances between paraspinal tissues and the spinal cord are short. In addition, substantial removal of the paraspinal tissues to access the spinal roots or spinal cord appears necessary. The preparation described in this report takes advantage of the anatomical fact that the L6 dorsal root enters the spinal cord 2-2.5 vertebral segments rostral to its passage through the intervertebral foramina. This effectively lengthens the distance between the lumbar paraspinal tissues and central recording sites. The preparation has five unique features: (1) the L6 and L7 vertebrae remain intact; (2) lumbar paraspinal tissues and their attachments to the L6 and L7 vertebrae remain intact on one side of the vertebral column; (3) the intact L6 vertebra can be loaded at its spinous process; (4) the magnitude of the load applied at the L6 spinous process can be controlled with a feedback motor; (5) the direction of load relative to the long axis of the spine can be controlled. Using this preparation, single unit recordings were obtained from the L6 dorsal root during controlled loading of the L6 lumbar vertebra at its spinous process. The responses of two paraspinal muscle proprioceptors to vertebral loading are characterized in this report. With existing electrophysiological techniques this preparation can be used to study central processing of paraspinal inputs. By combining mechanical loading of the lumbar spine in the presence of inflammatory mediators this preparation can contribute to the understanding of the mechanisms by which interactions between mechanical and chemical stimuli likely produce low back pain.     

单枚融合器行经椎间孔腰椎椎体间融合的解剖学观测

背景：有部分学者认为,与经椎间孔腰椎椎体间融合技术相关的手术器械是按照西方人体格设计,和国人体格存在一定的差异,甚至融合物难以置入,所以探讨相关的解剖技术就显得很有必要。 目的：测量腰椎椎间孔及与经椎间孔腰椎椎体间融合相关的解剖参数。 方法：对14具正常成人尸体脊柱腰段椎间孔宽度、长度、高度进行了观测;对腰椎各结构与后正中矢状面的距离进行了观测。 结果与结论： 结果表明腰段(L1~ L5)椎间孔宽度逐渐变小;L1 ~ L4椎间孔高度逐渐增大,L5略小于L4,L1 ~ L5高度均明显大于其宽度(P < 0.01);L1 ~ L5椎间孔长度逐渐增大(P < 0.05)。L1至L5 椎板峡部宽、下关节突最外侧缘至后正中矢状面距离逐渐增大,其性别间、左右间差异均无显著性意义(P > 0.05)。结果表明国人经椎间孔入路能满足高度9~14 mm单枚椎间融合器斜向置入,单枚椎间融合器置入不会因牵拉硬膜囊和神经根而导致脊髓与神经根损伤。     

Anterior Lumbar Interbody Fusion with Stand-Alone Interbody Cage in Treatment of Lumbar Intervertebral Foraminal Stenosis : Comparative Study of Two Different Types of Cages

Objective

This retrospective study was performed to evaluate the clinical and radiological results of anterior lumbar interbody fusion (ALIF) using two different stand-alone cages in the treatment of lumbar intervertebral foraminal stenosis (IFS).

Methods

A total of 28 patients who underwent ALIF at L5-S1 using stand-alone cage were studied [Stabilis® (Stryker, Kalamazoo, MI, USA); 13, SynFix-LR® (Synthes Bettlach, Switzerland); 15]. Mean follow-up period was 27.3 ± 4.9 months. Visual analogue pain scale (VAS) and Oswestry disability index (ODI) were assessed. Radiologically, the change of disc height, intervertebral foraminal (IVF) height and width at the operated segment were measured, and fusion status was defined.

Results

Final mean VAS (back and leg) and ODI scores were significantly decreased from preoperative values (5.6 ± 2.3 → 2.3 ± 2.2, 6.3 ± 3.2 → 1.6 ± 1.6, and 53.7 ± 18.6 → 28.3 ± 13.1, respectively), which were not different between the two devices groups. In Stabilis® group, postoperative immediately increased disc and IVF heights (10.09 ± 4.15 mm → 14.99 ± 1.73 mm, 13.00 ± 2.44 mm → 16.28 ± 2.23 mm, respectively) were gradually decreased, and finally returned to preoperative value (11.29 ± 1.67 mm, 13.59 ± 2.01 mm, respectively). In SynFix-LR® group, immediately increased disc and IVF heights (9.60 ± 2.82 mm → 15.61 ± 0.62 mm, 14.01 ± 2.53 mm → 21.27 ± 1.93 mm, respectively) were maintained until the last follow up (13.72 ± 1.21 mm, 17.87 ± 2.02 mm, respectively). The changes of IVF width of each group was minimal pre- and postoperatively. Solid arthrodesis was observed in 11 patients in Stabilis group (11/13, 84.6%) and 13 in SynFix-LR® group (13/15, 86.7%).

Conclusion

ALIF using stand-alone cage could assure good clinical results in the treatment of symptomatic lumbar IFS in the mid-term follow up. A degree of subsidence at the operated segment was different depending on the device type, which was higher in Stabilis® group.     

The pathophysiology of myelin basic protein-induced acute experimental allergic encephalomyelitis in the Lewis rat

Histological and electrophysiological studies were performed on Lewis rats with acute experimental allergic encephalomyelitis (EAE) induced by inoculation with guinea-pig myelin basic protein (MBP) and Freund's adjuvant. The histological studies showed demyelination in the lumbar, sacral and coccygeal dorsal and ventral spinal roots and to a lesser extent in the spinal cord, including the dorsal root entry and ventral root exit zones. The electrophysiological studies demonstrated reduced conduction velocities between the lumbar ventral roots and sciatic nerve. Conduction block was demonstrated at the ventral root exit zone of the lumbar spinal cord but was less severe than in rats with whole spinal cord-induced acute EAE. Recordings of the M wave and H reflex elicited in a hindfoot muscle by sciatic nerve stimulation showed a normal M wave, indicating normal peripheral nerve motor conduction, but a markedly reduced H reflex. The reduction in the H reflex is accounted for by demyelination-induced nerve conduction block in the dorsal and ventral spinal roots, intramedullary ventral roots and at the dorsal root entry and ventral root exit zones of the spinal cord. Demyelination and nerve conduction abnormalities were well established in the relevant lumbar segments on the day of onset of hindlimb weakness. It is concluded that demyelination in the lumbar ventral roots and to a lesser extent in the lumbar spinal cord, including the ventral root exit zone, is an important cause of hindlimb weakness in myelin basic protein-induced acute EAE in the Lewis rat.     

Spondylolisthesis accompanying bilateral pedicle stress fracture at two vertebrae

There has been no report of bilateral pedicle stress fractures involving two vertebrae. The authors describe a unique case of spondylolisthesis accompanying a bilateral pedicle stress fracture involving two vertebrae. De novo development of spondylolisthesis at the L5-S1 vertebrae accompanying a bilateral pedicle stress fracture at L4 and L5 was observed in a 70-year-old woman. The patient's medical history was unremarkable and she did not have any predisposing factors except severe osteoporosis. Interbody fusion with bone cement augmented screw fixation was performed. Surgical treatment resulted in good pain management and improved functional recovery.     

Diagnostic value of electrical stimulation of lumbosacral roots in radiculopathies*

Needle electrical stimulation of the lumbosacral roots at the laminar level of the Th12-L1 or L1-2 intervertebral spaces were performed in 24 normal subjects and 58 patients with various kinds of lumbar radiculopathy (unilateral L4, L5 and S1 herniated nucleus pulposus and lumber stenosis). The root stimulation method was compared with conventional needle EMG. Lumber electrical stimulation showed root abnormalities objectively in 80% of patients while the diagnostic value of needle EMG was 65%. Therefore, electrical root stimulation is superior to routine EMG for localizing lumbar root involvement. However, the only needle EMG demonstrated the root pathology in 7 cases (12%) and single electrophysiological abnormality was found by the root stimulation in 16 cases (27%). Thus, both electrophysiological methods should be complementary to each other in evaluation of the lumbar radiculopathy.     

The V2 segment of the vertebral artery in anterior and anterolateral cervical spinal surgery: a cadaver angiographic study

OBJECTIVE: The second segment of the vertebral artery is under the risk of injury during anterior and anterolateral cervical spine procedures. To avoid such a risk, one needs to be familiar with the regional anatomy. The aim of this study was to measure the distance between the vertebral artery and the uncinate process, midline, and the medial side of the longus colli muscle using vertebral artery angiograms at the level of C6, C5, C4, and C3 vertebrae. MATERIALS AND METHODS: In 12 human cadavers, the vertebral arteries were first irrigated with water. Then the arteries were filled with silicon and barium, and finally their angiographic images were obtained. RESULTS: The transverse diameter of the vertebral artery was measured at C6, C5, C4, C3, and C2 level. The values on the left were bigger than the values on the right (p>0.05). The distance between the vertebral artery and the midline decreased from C6 (17.2+/-5.6mm on the right, 17.2+/-2.3mm on the left) to C3 (15.8+/-5.3mm on the right, 13.8+/-2.1mm on the left) (p>0.05). The distance between the apex of the uncinate process and the medial side of the vertebral artery was found to be longer at C4 (2.7+/-1.0 mm on the right, 2.2+/-1.0mm on the left) and C5 (2.5+/-1.1mm on the right, 2.5+/-1.0mm on the left) vertebra levels on the right side (p=0.339 at C4, p=0.862 at C5). The distance between the medial side of the longus colli muscle and the medial side of the vertebral artery was measured as 9.7+/-2.7 mm (9.5+/-2.9 mm on the right, 9.8+/-2.6mm on the left) at C6 level, 9.2+/-2.6mm (8.6+/-2.4mm on the right, 9.8+/-3.1mm on the left) at C5, 9.4+/-1.9 mm (9.2+/-2.1mm on the right, 9.5+/-2.0mm on the left) at C4, and 10.4+/-2.7 mm (10.5+/-3.0mm on the right, 10.1+/-2.6mm on the left) at C3 vertebra level. No significant difference was found between the right and the left (p>0.05). The angle between the vertebral artery and the midline was measured as 4.0+/-1.9 degrees on the right and 2.2+/-1.4 degrees on the left side (p=0.030). CONCLUSION: It was considered that the values obtained could be useful in anterolateral and anterior cervical approaches in terms of evaluating the position of the vertebral artery and its relation to vertebral structures. It is also concluded that the risk of injury in upper subaxial cervical spine is higher than in the lower part of the subaxial cervical spine.     

下颈椎弓根CT图像的指标测量

背景：由于颈椎弓根较小的周径,高度的个体差异,周围复杂的解剖结构,在置椎弓根螺钉时易误伤脊髓、椎动脉及神经根,临床应用受到限制。正确的理解椎弓根及其周围结构解剖特点有助于提高经椎弓根螺钉内固定操作的安全性。 目的：评价CT测量颈椎椎弓根在颈椎弓根内固定的临床意义。 方法：随机选择81例正常成人颈椎CT片进行颈椎骨性指标的研究,测量指标包括13项：椎弓根高度、宽度,椎弓根内侧、外侧、上缘、下缘皮质厚度,椎弓根内松质骨高度、宽度,椎弓根轴线的骨性通道全长,椎弓根的长度1、长度2,椎弓根的内倾角和椎弓根轴线在矢状面上与椎体下终板之间的角度。 结果与结论：椎弓根宽度小于高度,C3、C4外径最小,颈椎椎弓根的松质骨内径小,皮质骨比例高。外侧皮质骨较内侧和上、下侧皮质骨均薄。下颈椎椎弓根的三个通道长度变化不显著,内倾角和上下倾角则有一定区别。提示经螺旋CT可以较好的呈现椎弓根内部的情况,为颈椎弓根螺钉内固定提供影像学数据。     

Reinnervation of denervated lumbar ventral roots and their target muscle by thoracic spinal motoneurons via an implanted nerve autograft in adult rats after spinal cord injury.

Intraspinally implanting a nerve autograft (NAG) to promote axonal regeneration toward periphery was investigated as a surgical treatment for spinal cord injury in adult rats. Fifteen animals underwent a left hemisection of the spinal cord at T12 level and an intradural section of all ipsilateral lumbar ventral roots. In repaired animals (n = 9), the electrophysiologically selected left L3 and L4 lumbar ventral roots supplying the quadriceps muscle were anastomosed to a NAG. The NAG was taken from the right peroneal nerve and then ventrolaterally implanted into the cord at a level 7 mm rostral to the hemisection. In the control group (n = 6), sectioned lumbar ventral roots were left unrepaired. Nine months later, the animals were assessed with clinical, electrophysiological, and histological examinations. Muscle action potential and motor evoked potential were obtained from the denervated/reinnervated quadriceps in all repaired animals, with a mean amplitude of 918.3+/-328.9 microV and 215.8+/-39.7 microV, respectively. Horseradish peroxidase retrograde labeling from the denervated/repaired lumbar ventral roots, performed in five repaired animals, showed that the mean of labeled neurons, ipsilaterally located in the thoracic ventral horn near the implantation site, was 145.8+/-111.7. Histological analysis showed numerous myelinated axons in the NAG and denervated/repaired lumbar ventral roots of all repaired animals. The study of neuromuscular junctions furthermore confirmed numerous newly formed endplates appearing in the denervated/reinnervated quadriceps. These changes were absent in the control animals. These data indicate that the rostral thoracic spinal motoneurons can innervate the caudal denervated/repaired lumbar ventral roots and the target quadriceps via an implanted NAG, thereby inducing some functional recovery in adult rats after lower thoracic spinal cord injury.     

X-ray computed tomography of lumbosacral roots and primary hypertrophic neuritis (Dejerine-Sottas disease)

CT without contrast of lumbosacral nerve roots was performed in 13 patients with peroneal atrophy and 28 control subjects. Two series of 5 mm serial sections parallel to the plane of the disk were examined at the L4-L5 and L5-S1 levels, and the transverse diameter of the S1 nerve roots measured at the lower part of the lateral recess. Results showed frank bilateral, grossly symmetrical hypertrophy of lumbosacral roots in 8 of the 13 patients. This hypertrophy involved all roots examined (L4, L5, S1), except in one case where only S1 roots were involved. Hypertrophy was often more marked on the distal part of the roots and on spinal nerves, contrasting with the sometimes normal or only slightly altered appearance of the nerve roots emerging from the dural sac. In these 8 cases, the diameter of the S1 nerve roots was 8 to 18 mm, in contrast to a mean of 3.5 +/- 1 mm in the 28 controls. CT scan images were normal in the remaining 5 patients. The presence of a CT image of nerve hypertrophy was in all cases associated with a marked fall in nerve conduction rate (median nerve motor conduction rate less than 25 msec-1), and a decrease in number of myelinated fibers with numerous onion bulbs. In contrast, the absence of CT nerve hypertrophy could not predict the results of electrophysiological and histological examinations.     

Relationship between the states of spinal impact injuries and magnetically evoked EMGs in rats

Abstract

The relationship between the states of spinal Impact injuries and magnetically evoked electromyograms (EMGs) were studied in rats. Impact injuries to the spinal cord were induced at a depth of 0.25-2.0 mm by insertion of a cylinder tip measuring 2 mm in diameter into the lumbar vertebrae L1-L2. Magnetically induced electromyograms for the brain and lumbar vertebrae L4-L5 were recorded from the tibialis anticus and the gastrocnemius muscles. H-reflex was not induced by the spinal cord injury (SCI) at a depth of 0.25 mm, although motor evoked potential (MEP) was observed. Continuous waves following the M- response were observed in the SCI at a depth of 0.25 mm. Elevation of the threshold, reduction of its latency and decrease in amplitude of the M-responses were observed at an injury depth of 0.5 mm or deeper. With SCI magnitude from mild (0.5 mm depth) to severe (1.0 mm depth), the amplitudes of the M-response were decreased, and the latency of the M-response was shorter than that of the control. The F-response was accelerated in severe SCI. Our results indicated that there was a relationship between extensive injury legions and the H-reflex F- and M-responses in magtnetically evoked EMGs. Magnetically evoked EMGs are useful for monitoring the states of SCI. [Neurol Res 2000; 22: 727-732]