Assessing the Stiffness of Spinal Fusion in Animal Models

The clinical goal of spinal fusion is to reduce motion and the associated pain. Therefore, measuring motion under loading is critical. The purpose of this study was to validate four-point bending as a means to mechanically evaluate simulated fusions in dog and rabbit spines. We hypothesized that this method would be more sensitive than manual palpation and would be able to distinguish unilateral vs bilateral fusion. Spines from four mixed breed dogs and four New Zealand white rabbits were used to simulate posterolateral fusion with polymethyl methacrylate as the fusion mass. We performed manual palpation and nondestructive mechanical testing in four-point bending in four planes of motion: flexion, extension, and right and left bending. This testing protocol was used for each specimen in three fusion modes: intact, unilateral, and bilateral fusion. Under manual palpation, all intact spines were rated as not fused, and all unilateral and bilateral simulated fusions were rated as fused. In four-point bending, dog spines were significantly stiffer after unilateral fusion compared with intact in all directions. Additionally, rabbit spines were stiffer in flexion and left bending after unilateral fusion. All specimens exhibited significant differences between intact and bilateral fusion except the rabbit in extension. For unilateral vs bilateral fusion, significant differences were present for right bending in the dog model and for flexion in the rabbit. Unilateral fusion can provide enough stability to constitute a fused grade by manual palpation but may not provide structural stiffness comparable to bilateral fusion.     

颈椎病伴椎管狭窄患者再手术问题探讨

目的：探讨颈椎病伴椎管狭窄患者再手术的原因、手术方式及其相关问题。方法：我院2002年7月～2003年12月对40例颈椎病伴椎管狭窄术后疗效不佳或症状复发的患者进行了后路多节段（5个或以上）减压手术。根据其手术治疗方式及影像学资料分析再手术原因，并进行术后疗效评价。结果：经前路手术者再手术的主要原因为：（1）伴有多节段颈椎管狭窄因素时，只选择部分压迫重的节段行减压融合15例；（2）经前路多节段（≥3个节段）减压融合后，相邻节段继续退变，出现新的脊髓压迫表现及椎间不稳定9例；（3）伴有OPLL时，行部分节段前路减压融合后，病变呈进展表现，产生或加重对脊髓的压迫8例。经后路手术者再手术的原因为：（1）后路减压节段不够5例（包括1例前后路联合手术者）；（2）后路减压不充分3例。再手术后随访1．3～2．7年，平均2．1年，所有患者脊髓功能获得一定的提高，JOA评分改善率为51．3％。结论：颈椎病伴椎管狭窄病例再手术的主要原因为椎管狭窄因素仍然存在，经后路多节段（5个或以上）减压手术治疗可彻底去除颈椎管狭窄因素，有效解除脊髓前、后方所受的压迫，可获得较满意的临床疗效。     

胸腰椎骨折术后内固定松动、断裂的原因及预防

目的 探讨椎弓根螺钉系统用于胸腰椎骨折术后出现松动、断裂的原因，并提出相应的预防对策。方法 12例胸腰椎骨折术后内固定失效病例，采用RF系统3例，AF系统9例。均未行植骨融合，AF系统中未按要求安装横连结3例，术后伤椎前缘高度平均恢复至正常的85．2％。结果 术后8—21个月出现棒断裂4例，螺钉断裂3例，钉帽松动5例。结论 内固定物的自身问题、术者的经验欠缺及操作不规范是胸腰椎骨折术后椎弓根螺钉系统松动、断裂的原因，但伤椎骨结构未能得到良好重建及术后椎间盘退变可能是其更重要的因素。因此重视内固定物的选择、加强规范操作，强调对损伤椎体及椎间盘的全面处理是预防内固定失效的有效措施。     

脊髓血管母细胞瘤的显微手术治疗(附11例分析)

目的探讨脊髓血管母细胞瘤的临床特点和外科治疗技巧。方法回顾性分析11例脊髓髓内血管母细胞瘤的诊治经验。本组临床表现主要为感觉和运动障碍、肌肉萎缩及大小便失禁。均经后正中入路切除肿瘤,术中及术后常规使用甲基强的松龙。结果肿瘤均获全切除。术后短时间内症状改善8例,无变化2例,加重1例,无手术死亡。结论本病根据术前典型的影像资料均可确诊。术中尽可能避免活检或分块切除肿瘤,以免引起难以控制的出血和盲目止血引起的脊髓损害。大剂量甲基强的松龙可减轻脊髓水肿。     

大鼠大脑皮质向脊髓与红核投射的比较

目的 比较大脑皮质向脊髓与红核发出投射的区域并探讨是否有分支投射存在。方法 将。TB及NY分别注入大白鼠的脊髓与红核内，在大脑皮质观察比较标记细胞出现的部位。结果 FB标记细胞出现在24，10，8，6，4，3，1，2，23，29b，29c，18，7，13，39区。NY标记细胞出现于6，4，3，1区，10区的尾侧部及7，18区的颅饲部亦有少量存在。无发现双标记细胞。结论 大脑皮质向脊髓发出投射的区域非常广泛，向红核发出投射的区域全部重叠于皮质脊髓神经元分布的区域内，皮质脊髓神经元无分支投射到红核。     

Neurally Augmented Sexual Function in Human Females: A Preliminary Investigation

Objective. Neurally augmented sexual function (NASF) is the production of pleasurable genital stimulation and subsequent orgasm through the application of electrical energy to provide stimulation of the spinal cord or peripheral nerves. The purpose of this paper is to demonstrate the reproducibility of this phenomenon. Materials and Methods. Eleven otherwise healthy women, ages 32–60 years, were selected for this study. Through standard techniques, quadripolar (octopolar in the final patient) leads were placed in the epidural space percutaneuously. The lead was maneuvered initially to an L1–L2 position and then repositioned based on feedback from the patient. The patients were allowed to utilize the device ad libitum for up to 9 days. Results. Successful stimulation was achieved in 91% (10/11) of patients. These women described a greater frequency in sexual activity, increased lubrication, and overall satisfaction. A smaller subset had substantial improvement in sexual function as measured by orgasmic capacity. This subset consisted of women with secondary anorgasmia. A return of orgasmic capacity was found in 80% (4/5) of patients having secondary anorgasmia with an average intensity of ≥ 3/5 while using the device. Once the device was removed, the patients returned to their previous anorgasmic status. Conclusions. Pleasurable genital stimulation of the spinal cord is a consistently reproducible phenomenon. In a subset of the population studied, improvement in orgasmic function was noted. This was noted in the group with secondary orgasmic dysfunction.     

胫骨前肌疲劳时比目鱼肌诱发肌电图H波的变化及其机制探讨

为了解主动肌疲劳时拮抗肌脊髓运动神经元兴奋性变化的规律 ,本研究采用踝关节背屈运动形式 ,对胫骨前肌 (主动肌 )疲劳状态下的比目鱼肌 (拮抗肌 )诱发肌电图H波成分进行了观察。并以压迫阻断胫骨前肌Ⅰa类神经纤维传导的方法 ,对比目鱼肌H波变化机制进行了分析探讨。结果发现 :(1)胫骨前肌疲劳后 ,比目鱼肌H波明显受到抑制 ,与安静时比较呈非常显著性差异 ;(2 )胫骨前肌Ⅰa类神经纤维传导被阻断后 ,比目鱼肌H波的抑制现象没有解除。表明 ,胫骨前肌疲劳时比目鱼肌H波被抑制的原因 ,可能是由于主动肌内的代谢产物激活了Ⅲ·Ⅳ类神经纤维的感受器 ,Ⅲ·Ⅳ类神经纤维的传入冲动增加 ,使Ⅰa抑制性中间神经元被激活 ,导致拮抗肌脊髓运动神经元的兴奋性受到了抑制     

A New and Alternative Leads Positioning for Complex Regional Pain Syndrome Treatment: Paraforaminal Stimulation

We present a case of a female patient suffering from type I complex regional pain syndrome (CRPS) who developed “mirror imaging” of her CRPS and was successfully treated with dual spinal cord stimulation (SCS) in the paraforaminal epidural space. This patient initially had unilateral pain that was unsuccessfully treated with midline SCS and single‐lead lateral epidural lead placement “paraforaminally.” One year later, because we believed that paraforaminal stimulation would preferentially stimulate primary sensitized afferents innervating the painful area, we reperformed SCS with two leads positioned laterally and paraforaminally close to the roots within the epidural space. After repositioning and after 1 year of paraforaminal stimulation, there was significant improvement in the patient's symptoms, resolving all unilateral and “mirrored” symptoms. We conclude that paraforaminal stimulation may be a valid therapeutic option for the treatment of CRPS.     

脊柱放线菌感染并发脊髓压迫症(附3例报告)

目的探讨脊柱放线菌感染并发脊髓压迫症的临床和影像学特点及治疗方法。方法回顾性分析3例经病理检查证实的本病患者的临床资料。结果3例患者均有颈、胸脊椎及软组织感染和脊髓压迫症状;MRI示病变椎体骨质破坏,颈、胸硬膜外软组织肿块,脊髓受压。病理学检查组织病理学检查证实3例均为放线菌感染,2例表现为炎性肉芽组织伴微脓肿形成,另1例表现为硬膜外脓肿。均予以脓肿清除、脊髓减压术,并给予4~8周大剂量青霉素G静脉滴注,后改口服维持4~6个月,术后及随访3例患者均取得显著的疗效。结论脊柱放线菌感染并发脊髓压迫症临床和影像学表现无特征性,其确诊依赖于病理学和微生物学检查。脓肿引流、椎管内减压术和大剂量抗生素治疗有效。     

脊髓损伤后中枢性疼痛的实验模型和机制研究进展

中枢性疼痛(central pain,CP)是脊髓损伤(spi-nal cord injury,SCI)的顽固性合并症,为患者主观上感到损伤平面以下皮肤痛觉消失区一种以自发痛为主的疼痛,发生率为11%~94%,严重者为5%~30%。近年来其发生率逐年增高,使很多患者陷于抑郁、药物成瘾、甚至自杀的悲惨境地。许多疼痛