椎管内髓外硬膜下肿瘤的外科治疗

目的：探讨椎管内髓外硬膜下肿瘤的临床特点及手术中应用内固定重建脊柱稳定性的疗效。方法：手术治疗椎管内髓外硬膜下肿瘤24例，男14例，女10例；年龄12～68岁，平均40岁。14例在切除肿瘤后应用内固定及自体植骨，10例未行内固定及植骨。结果：本组24例均行后路一次手术切除肿瘤，平均随访22个月（6～36个月），肿瘤无复发，术后脊髓损伤无加重。随访Frankle分级提高1-3级，无血管、神经并发损伤。植入内固定者无固定物断裂、松动，固定效果满意，相应植骨部位均形成骨性融合。结论：椎管内髓外硬膜内肿瘤外科切除同时结合植骨内固定可有效保持脊柱的稳定性。     

Pituitary carcinoma recurrent to the lumbar intradural extramedullary space: case report

Context

Pituitary tumors are rare, and pituitary carcinomas are rarer still. Prognosis is poor, with less than 50% of patients surviving past 1 year after diagnosis. In this case of spinal metastasis from an adrenocorticotropic hormone-secreting pituitary carcinoma, the intradural extramedullary metastases recurred in the same lumbar area 6 years apart.

Findings

Fourteen years prior to presentation in our clinic, a 48-year-old woman was diagnosed with pituitary adenoma which was treated with resection followed by radiation. Eight years later, an intradural extramedullary spinal drop metastasis at L2–L3 was again treated with resection and radiation. Three years later, magnetic resonance imaging (MRI) revealed a mass encasing the right carotid artery, which was treated for 1 year with chemotherapy using temozolomide (Temodar). Three years later, MRI showed intradural extramedullary metastases at the L3–L4 intervertebral disc space and behind the L3 vertebral body; treatment was again resection followed by radiation. Back pain and weakness resolved after surgery and her neurological examination returned to baseline. There was no evidence of recurrence 1 year after surgery.

Conclusion/clinical relevance

In this unusual case, this pituitary carcinoma metastasized twice in 6 years to virtually the same intradural extramedullary lumbar region. Surgical resection of these masses aided in relieving neurological symptoms and prolonging life.     

Spinal intradural primary germ cell tumour—review of literature and case report

Background  Primary spinal cord germ cell tumour is a rare tumour. We herein review the tumour characteristics, associated risk factors, treatment policy, and patterns of failure of primary intradural germ cell tumour. Method  We conducted a PUBMED search using a combination of keywords such as “spinal germ cell tumor,” “germinoma,” “extradural,” “intradural,” “intramedullary,” “extramedullary,” and identified 19 cases of primary spinal germ cell tumour. Clinical features, pathologic characteristics, and treatment details of these patients including status at follow-up were noted from respective case reports. We also describe a case of a young Indian patient of intradural extramedullary germ cell tumour treated with a combination of surgery, chemotherapy, and radiotherapy. Findings  The median age at presentation was 24 years. The most common location of the tumour was thoracic (40%). β-HCG overproduction was noted in 40% of the patients. Most patients were treated with a combination of surgery, radiation therapy, and systemic chemotherapy. Median follow-up was 16.5 months. Recurrence was observed in 10% of the patients, all in β-HCG over-producing tumours. The illustrative case was a 28-year male, presenting with pain in lower back and both lower limbs for 2 months. Magnetic resonance imaging spine showed an inhomogeneous hyperintense soft tissue mass at L₂-L₄ spinal level. He was treated with complete surgical excision and four cycles of chemotherapy with BEP regimen following a histological diagnosis of non-seminomatous germ cell tumour. Palliative irradiation to the lumbar spine was given on progression at 3 months. The patient eventually succumbed to his condition, due to compressive transverse myelitis possibly due to cervical cord metastasis. Conclusion  Limited surgery followed by upfront radiation therapy and adjuvant chemotherapy is the optimal management of this rare group of tumour. Omission of radiation therapy from the treatment armamentarium might engender local recurrence and spinal dissemination at first failure.     

Delayed occurrence of spinal arachnoiditis following a caudal block

Abstract

Context

Spinal arachnoiditis is a rare disease caused by fibrosis and adhesion of the arachnoid membrane due to chronic inflammation. The causes of arachnoiditis are infection, spinal surgery, intraspinal injection of steroid or myelography dye, and spinal anesthesia.

Method

Case report.

Findings

A 60-year-old woman presented with progressive weakness and sensory change of both legs and urinary symptoms. She had received a single caudal block 6 months before symptom onset. Magnetic resonance imaging of the thoraco-lumbar spine showed an intradural extramedullary tumor at the T5–T7 level. She underwent laminectomy and tumor resection. The pathological finding was arachnoiditis. After surgery, a rehabilitation program of strengthening exercises of both lower extremities and gait training was started. At 2-month follow-up, she was able to walk with orthoses and performed daily activities with minimal assistance.

Conclusion

Symptoms of spinal arachnoiditis occurred 6 months after a single caudal block in this woman. Clinicians should be aware of this possible delayed complication.     

脊柱外周型原始神经外胚层肿瘤影像学表现(7例报告)

目的观察脊柱外周型原始神经外胚层肿瘤(pPNET)的影像学表现。方法回顾性分析7例经病理证实的脊柱pPNET患者的影像学资料。结果 7例脊柱pPNET病例中,男性4例,女性3例。病变位于颈段(C2~7)1例,颈胸段(C7~T2)1例,胸段(T10~12)1例,腰段(L3~4、L4~5)2例,腰骶段(L1~S2)1例,骶段(S1~4)1例;其中,髓外硬膜内1例,硬膜外6例。MR(n=7)和CT(n=4)检查表现为硬膜内或硬膜外肿块,信号/密度不均,T1WI为等或稍低信号,T2WI为稍高信号,CT为等密度,增强扫描呈不同程度不均匀强化。肿瘤位于髓外硬膜内者可伴有多发蛛网膜下腔转移,硬膜外pPNET肿瘤的主体部分多位于椎骨或椎旁组织,肿块椎管内部分累及多个椎体平面,并通过椎间孔、骶孔与椎旁部分沟通。结论脊柱pPNET可表现为髓外硬膜内或硬膜外肿瘤,确诊依赖病理及免疫组化检查。     

椎管内髓外硬膜下多发性肿瘤的诊断与手术治疗

目的探讨椎管内多发性肿瘤的诊断及治疗方法。方法本组男11例,女4例。年龄16～81岁,（51.0±21.2）岁。病程2～27月,（11.0±7.6）月。均无皮肤咖啡斑及体表神经纤维瘤,头颅MR未见异常。增强MR示椎管内髓外硬膜下肿瘤46个,其中≥0.5cm肿瘤35个,肿瘤累及颈段1例,累及胸段5例,累及腰骶段12例。手术方法：采用后正中入路椎板切除术切除肿瘤,〈1cm者切除半椎板,在显微镜下操作,力争保留重要的载瘤神经而将肿瘤自神经上剔除,如肿瘤与神经无法分离,尽可能游离神经根在切除肿瘤后行神经根吻合。术后常规应用抗生素及激素治疗,术后戴颈围领、围腰保护2个月,同时训练腰背部肌肉。结果15例手术肿瘤全切12例,其中1例行神经根吻合;未全切的3例中2例术前诊断为多发神经纤维瘤或神经鞘瘤,因部位散在且直径〈0.5cm未考虑手术切除,另1例术中见肿瘤与多根神经根粘连,病理为转移瘤,仅行部分切除减压术。手术共切除肿瘤33个。病理：神经鞘瘤8例,神经纤维瘤1例,室管膜瘤2例,黑色素瘤1例,腺癌转移1例,脊膜瘤2例。黑色素瘤患者于术后22个月死亡,转移瘤患者于术后1年死亡,余13例随访4～72个月,平均30.1月,肿瘤无复发增长,其中2例多发神经鞘瘤未手术全切除者分别随访12、43个月,肿瘤无明显增长。13例存活者术后KPS评分较术前均有改善（术前75.4±13.3,术后最后一次随访时97.7±6.0,t=-7.366,P=0.000）。结论椎管内髓外硬膜下多发肿瘤以良性居多,中老年多见,半椎板及次全椎板入路显微手术切除是有效的治疗方法,〈0.5cm的无症状肿瘤可严密随访。     

胸腰椎管内神经鞘膜瘤影像学表现和手术治疗的临床观察

目的:探讨胸腰段神经鞘膜瘤的影像学特点和手术治疗效果。方法:自2005年6月至2012年12月,手术治疗胸腰椎管内神经鞘膜瘤17例,其中男11 例,女6 例;年龄46～67 岁,平均53 岁;病程3～5 年,平均3.3 年。胸段患者表现为胸背痛,逐渐出现下肢麻木无力或行走不稳;腰段表现为腰背痛,下肢放射痛或感觉麻木,以及间歇性跛行。术前VAS评分 (疼痛视觉模拟标尺法) 5～8分,平均6.12分。11例患者神经功能受损,Frankel C级4例,D级5例,E级2例。CT和MRI检查提示病变部位:胸段3例,胸腰段5例,腰段3例,腰骶段6例;硬膜外5例,髓外硬膜下12例。6例单纯行椎管减压、肿瘤切除术,11例行椎管减压、肿瘤切除及后路内固定植骨融合术。结果:术中未发生大血管或脊髓损伤,术后伤口均正常愈合。17例患者术后均获随访,时间12～60 个月,平均32个月。胸背痛、腰背疼痛和下肢放射痛等显着改善,下肢麻木感明显缓解。末次随访VAS评分 0～3分,平均1.5分。神经功能受损患者末次随访Frankel分级:D级5例,E级6例。结论:MRI 是胸腰段神经鞘膜瘤有效的辅助诊断方法,影像学表现决定具体手术方法,手术目的是椎管有效减压、肿瘤彻底切除和脊柱稳定性的重建。     

Spinal hemangiopericytoma: an institutional experience and review of literature

Purpose

Hemangiopericytoma is a rare tumor of CNS with potential for recurrence and widespread metastasis, even outside CNS with even rare involvement of spinal cord. This case series presents five patients to evaluate the clinical presentation, radiological features, management, pathology and outcome of spinal hemangiopericytomas.

Methods

Between 2004 and 2013, five patients underwent surgery for spinal hemangiopericytoma. Histopathological data were reviewed in all cases and clinical and follow-up details were collected from the data available in our department.

Results

There were three males and two females, including one pediatric patient. Three patients had dorsal spine involvement and two patients had involvement of cervical spine. There were two patients with intradural extramedullary tumors, one patient each with pure intramedullary tumor, pure extradural tumor and both intra and extradural tumor. All of them presented with motor weakness. Gross total resection of the tumor was done in three patients. Four patients received post-operative radiotherapy. Histopathology showed anaplastic tumor in four cases with high MIB-1 LI. Most of them were positive for CD34, mic-2 and bcl-2. Three patients who underwent gross total resection improved significantly in the follow-up period. Two patients who underwent subtotal resection expired due to spread of their disease.

Conclusion

Spinal hemangiopericytoma is a rare tumor. Strong clinical suspicion is required to diagnose it pre-operatively. Gross total resection is the goal and radiotherapy should be given in case of residual tumor or high-grade tumors.

     

Feasibility of unilateral hemilaminectomy utilizing a Williams retractor for the resection of intradural-extramedullary spinal neoplasms

BackgroundWhile open approaches have historically been used in the surgical treatment of intradural-extramedullary spine tumors, minimally-invasive surgical (MIS) techniques are frequently applied to minimize post-operative complications associated with open surgery. Tubular retractor systems in particular have been employed in combination with the unilateral hemilaminectomy (UHL) approach. Here we describe the use of a Williams retractor as a safe and effective minimally-invasive alternative to tubular retractor systems with similar post-operative outcomes.MethodsWe retrospectively reviewed a cohort of eight patients who underwent unilateral hemilaminectomy using a Williams retractor for the minimally-invasive resection of intradural-extramedullary neoplasms at a large tertiary academic center from 2017 to 2019. Patient demographics, pathologic specimens, radiographic studies, and intraoperative parameters were collected and analyzed.ResultsIn our series, gross total resection was achieved in all cases. Average operative time was 158 ± 40 minutes, the mean estimated blood loss (EBL) was 44.4 ± 30.4 mL, and mean length of stay was three days. All patients reported symptomatic improvement at follow-up as reported by Visual Analog Scale scores.ConclusionA Williams retractor yields similar outcomes with respect to post-operative pain, operative time, and EBL as it maintains the advantages of the UHL approach in the resection of intradural-extramedullary spine tumors while enhancing feasibility and providing significant cost savings.     

Efficacy,safety, and reliability of surgery on the lumbar spine under general versus spinal anesthesia- an analysis of 64 cases

Quasi-experimental design purposeCompare intra and postoperative parameters, surgeons’ satisfaction, and cost-effectiveness between general anesthesia (GA) and spinal anesthesia (SA) on patients undergoing surgery in the lumbar spine surgery.Overview of literatureSurgery on the lumbar spine is the commonest surgical procedure among all spinal surgical practices. Both the GA and SA are shown to be suitable techniques for performing the surgery safely. GA is used most frequently. But, SA became increasingly more popular because it allows the patient to self-position thereby reducing various complications associated with GA in a prone position.MethodsA total of 64 patients from June 2016 to July 2019 who underwent either discectomy, laminectomy, or lamino-foraminotomy for herniated lumbar disc or canal stenosis in 1 or 2 levels were included. During the study period, 32 patients were non-randomly selected for each of the GA and SA groups. The heart rate (HR), mean arterial pressure (MAP), blood loss, total anesthetic time, surgeons’ satisfaction, analgesic requirements, cost of the procedure, and hospital stay were recorded and compared.ResultsIn the context of demographic characteristics, baseline HR, or MAP, no significant differences were noted between SA and GA groups. Mean anesthetic time, mean PACU time, mean doses of analgesic requirement, cost of anesthesia, and the surgeon’s satisfaction was significantly lower in the SA Group (P < 0.05). The blood loss, duration of operation, and hospital stay were not significant too. No major Intra and postoperative complications were reported nor were significant differences found in either series.ConclusionSafety and efficacy of SA in comparison to GA were similar for the patients undergoing surgery on the lumbar spine. Notable advantages of SA include shorter anesthesia duration, fewer drug requirements, relative cost-effectiveness, and fewer complications rate. Successful surgery can be performed using either anesthesia type.     

全内镜下腰椎纤维环缝合术的技术要点及临床疗效分析

目的 :介绍全内镜下腰椎纤维环缝合术的技术要点,分析全内镜下腰椎间盘摘除、纤维环缝合术的临床疗效。方法:纳入2018年1月至2018年11月采用全内镜下腰椎间盘摘除、纤维环缝合术治疗的50例非包含型腰椎间盘突出症患者,根据病变节段选择经椎间孔入路全内镜下单针缝合术或经椎板间隙入路双针缝合术。术后第2天、3个月分别复查腰椎MRI及CT以评估突出椎间盘组织摘除的彻底性及神经减压的充分性。分别于术后第2天及3、6、12个月采用视觉模拟评分(visual analogue scale,VAS,100分制)评估患者疼痛症状缓解情况,于术后3、6、12个月采用Oswestry功能障碍指数(Oswestry Disability Index,ODI)评价患者腰椎功能恢复情况,术后1年随访时采用Macnab评定标准评估腰椎功能,记录神经根功能(感觉、肌力及反射)恢复状况。结果:所有手术顺利完成,采用经椎间孔入路27例(包括L_3,48例、L_4,519例),经椎板间隙入路23例(包括L_4,511例、L₅S_1<...     

Metastatic intradural extramedullary spinal cord tumor from ovarian cancer: A case report with a literature review

Context: Metastatic intradural extramedullary spinal cord tumors are extremely rare.Findings: A 76-year-old woman presented with intractable neck pain. Three years earlier, she had been treated for ovarian cancer with bilateral salpingo-oophorectomy. A year later, she underwent resection of a brain metastasis. Magnetic resonance imaging (MRI) showed an encapsulated intradural extramedullary mass at C4–C5. C4–C5 hemilaminectomy, tumor resection, and biopsy were performed. Histological examination of the resection revealed an adenocarcinoma. After surgery, her intolerable neck-shoulder pain was fully resolved, and she had no difficulties with daily living activities. However, two months later, she underwent gamma knife radiosurgery for the recurrent metastatic brain tumor, and four months later, she died from cachexia.Conclusion: Although cases of metastatic intradural extramedullary spinal tumors from ovarian cancer are extremely rare, their possibility should be considered in the differential diagnosis. A history of brain metastases and enhancement on T1-weighted MRI were helpful for making an accurate diagnosis.     

Intradural metastatic spinal cord compression from ACTH-secreting pituitary carcinoma

Summary. Pituitary carcinomas are uncommon and intradural metastatic spread to the spine is rarer still. We describe a 27-year old man with metastatic spinal cord compression from an adrenocorticotrophic hormone (ACTH) cell pituitary carcinoma, 16 years following the initial presentation. He had three previous resections of the pituitary tumour and post-operative radiotherapy. The intradural, extramedullary spinal metastases causing thoracic and lumbar cord compression were excised, with neurological improvement.Spinal metastases in pituitary carcinoma are uncommon, but aggressive surgical resection of the spinal metastases produces good symptomatic relief.     

内镜治疗腰椎间盘突出症合并椎体后缘离断

目的:探讨全脊柱内镜下治疗腰椎间盘突出症合并椎体后缘离断的有效性及安全性。方法:自2015年1月至2018年1月,采用全脊柱内镜治疗腰椎间盘突出症合并椎体后缘离断患者21例,男17例,女4例;年龄18～48岁,中位年龄27岁,其中16例<30岁;病程6个月～5年,中位病程21个月。均为单节段单侧椎间盘突出,采用椎板间入路,于镜下症状侧单侧摘除突出椎间盘,全部或部分切除离断的骨块。结果:所有病例无切口感染、椎间隙感染、肠道损伤、硬脊膜损伤、脑脊液漏等并发症发生。手术时间32～92 min,中位时间57 min。术后影像学检查示椎体后缘离断骨块完全切除2例,部分切除16例,未切除3例;椎间盘均彻底摘除。21例均获随访,时间12～36个月,中位时间15个月。腰痛视觉模拟评分(visual analogue scale,VAS)评分,术前(7.10±1.20)分,术后3 d(3.46±0.23)分,术后6个月(2.36±0.19)分;腿痛VAS评分,术前(8.80±0.55)分,术后3 d(3.54±0.28)分,术后6个月(2.59±0.26)分;Oswestry功能障碍指数评分,术前...     

Incisional hernia after extreme lateral interbody fusion on the lumbar spine: A case report

IntroductionExtreme lateral interbody fusion is a minimally invasive lateral transpsoas approach for spine surgery. We herein report a case of an incisional hernia after an extreme lateral interbody fusion on the lumbar spine that was successfully treated by laparoscopic surgery with intraperitoneal onlay mesh repair.Presentation of caseA 78-year-old woman was referred to our hospital with a complaint of left abdominal bulge and pain. She had undergone an extreme lateral interbody fusion for a lumbar spinal canal stenosis from L1 to L4 a year prior. Abdominal computerized tomography showed a left lumbar incisional hernia, and laparoscopic surgery was performed. The hernia orifice was sutured closed and covered with mesh. The patient was discharged five days after the operation with no complications.DiscussionWhen performing XLIF for a spinal disorder, the muscles should be separated bluntly along their fibers to prevent muscle atrophy, and the incised fascia should be securely sutured closed. Abdominal wall incisional hernias can occur after spinal surgeries such as extreme lateral interbody fusion.ConclusionLaparoscopic repair for abdominal wall incisional hernia after spine surgery is safe and feasible.     

显微内窥镜下单侧入路双侧减压治疗腰椎椎管狭窄症

目的 探讨显微内窥镜下利用单侧入路双侧减压技术治疗腰椎椎管狭窄症的手术适应证及临床疗效.方法 2005年2月至2007年6月,采用显微内窥镜下单侧入路双侧减压技术治疗腰椎椎管狭窄症患者53例,男36例,女17例;年龄52～75岁,平均57岁.全部病例均有腰痛、单侧或双侧下肢疼痛、麻木及神经性间歇性跛行病史,其中有双下肢症状者均自觉一侧下肢症状较重.所有患者术前均行腰椎X线摄片、CT、MR等影像学检查确诊为单节段腰椎椎管狭窄症,并结合临床表现排除退变性腰椎失稳、多节段腰椎椎管狭窄.术后患者获得平均16个月(8～26个月)的随访,采用视觉模拟评分法(visual analogue scale,VAS)及腰椎功能障碍指数(Oswestry disability index,ODI)评定患者手术后的疗效.结果 术后无硬脊膜撕裂、神经根损伤等严重并发症发生.VAS及ODI评定结果显示患者手术前后的VAS及ODI分值改变有统计学意义(P<0.01).术后CT显示椎管得到有效扩大,解剖结构破坏较少.结论 显微内窥镜下单侧入路双侧减压技术减压效果良好,复发率低,适用于早期症状较轻的单节段腰椎椎管狭窄症患者.     

Non-dysraphic intramedullary spinal cord lipoma of the child: Report of 3 cases

Background and purposeNon-dysraphic intramedullary spinal cord lipomas (NDSCL) represent 1% of spinal cord tumors. They are less frequent than dysraphic spinal cord lipomas and clinical presentation is unspecific. There are no guidelines on surgical management.Material and methodsWe report three observations of NDSCL in children, focusing on the clinical presentation, surgical management and postoperative outcome.ResultsThe patients, one female and two males, aged from 5 months to 10 years presented with neurological deterioration, pain, spinal rigidity and in two cases, a subcutaneous mass. Spinal MRI found intradural lipomas without spina bifida, located in the cervico-thoracic area in all cases. The lipoma extended to the medulla oblongata in two cases and was in the lumbar region in the third. These lipomas were massive, requiring decompression surgery. Surgery confirmed the lipoma to be subpial. We performed debulking of the lipoma without attempting total resection, and with or without dural plasty and laminoplasty, followed by minerva cast in two cases, and avoidance of standing in the youngest. Satisfactory recovery occurred in all three cases. After a follow-up between 4 months and 9 years, the outcome was favorable in all cases, and no patient presented with secondary spinal deformation or lipoma progression.ConclusionNDSCL is a rare entity, which often manifests with progressive pain and neurological deficits. In our experience, partial resection with or without dural plasty and laminoplasty has been associated with satisfactory postoperative outcomes and no recurrence of symptoms. We should be attentive to the risk of postoperative spinal deformity in these young patients.     

Intradural extramedullary mature cystic teratoma: not only a childhood disease

OBJECTIVE: The authors report on the first case of a spinal intradural extramedullary cystic teratoma in an aged patient. These lesions have been reported in adolescents and young adults often with a history of spinal dysraphism. They are believed to be congenital lesions; however, they have also been reported in patients with a history of posterior spinal surgery or lumbar puncture. METHOD: An 85-year-old man was evaluated for persistent and progressive lower extremity paresis. His symptoms began after relatively minor trauma. He had no prior lumbar surgeries. Neuroimaging studies revealed an L1-L2 intradural mass. A putative diagnosis of a cystic intradural extramedullary mass was made. A lumbar laminectomy and durotomy were performed. RESULTS: A cystic lesion containing hair follicles, cartilage, adipose, and neural tissue was encountered. Pathologic review corroborated the diagnosis of cystic teratoma. CONCLUSIONS: The occurrence of cystic teratomas in the absence of previous surgery or lumbar puncture is uncommon. Even rarer are reports of these lesions in aged patients. Of particular interest in this case is the fact that this patient had not undergone any previous lumbar procedures nor did he have a history of spinal dysraphism. Though rare, this entity should be included in the differential of cystic intradural spinal cord lesions.     

组配型横突拉钩的研制与临床应用

目的研制组配型横突拉钩并探讨其临床应用效果。方法通过腰椎骨骼标本和腰部软组织的观察、测量,设计制作了以腰椎横突为固定支点的组配型拉钩,将其应用于单侧椎弓根螺钉联合对侧经皮椎板关节突螺钉固定并椎间融合植骨的手术方式,并与传统椎板拉钩的使用进行比较。对比2组病例手术时间、术中出血量、术后切口引流液量、切口长度、术后72 h腰部切口疼痛视觉模拟量表(visual analogue scale,VAS)评分。采用日本骨科学会(Japanese Orthopaedic Association,JOA)下腰痛评分法对临床效果进行评价和对比。结果在手术时间、术中出血量和切口长度方面,组配型横突拉钩组优于椎板拉钩组,差异有统计学意义(P0.05);而在术后切口引流液量、术后72 h腰部切口疼痛VAS评分及最后随访JOA评分方面2组相比差异无统计学意义(P0.05)。结论与传统椎板拉钩相比,组配型横突拉钩具有容积小、组装方便、把持性好、固定确切、视野大、对手术操作干扰小以及适合人群和手术方式广泛等优点,可作为腰椎后路内固定手术的显露工具。