Minimally invasive spine surgery: an animal model for endoscopic approach to the anterior cervical and upper thoracic spine

BACKGROUND: Minimally invasive video-assisted techniques are currently used for thoracic and lumbar spine surgery with the aim of reducing the morbidity. Recently, an endoscopic approach has been used for endocrine neck surgery, with reduced pain and improved cosmetic results. PURPOSE: To develop an animal model for an endoscopic neck approach to the anterior cervical and upper thoracic spine. METHODS: Five pigs were used. A combination of one 5- and two 3-mm laparoscopic instruments was used to dissect the spine, and dedicated instrumentation was then used to perform discectomies. Carbon dioxide was insufflated at 10 mm Hg. Dissection was carried out upward and downward on the anterior aspect of the spine; discectomy was performed at various levels and evaluated at autopsy. RESULTS: All pigs tolerated the procedure well. Visibility of the cervical spine was excellent, and exposure from C1 to T3 was obtained. For discectomy, an additional 10-mm trocar was inserted, and discectomy of C3-C4 and C4-C5 was performed. Proper location and adequacy were confirmed at autopsy. CONCLUSION: The endoscopic neck approach allows exposure of the entire cervical spine and the upper thoracic spine in the porcine model. This approach has the potential to reduce the morbidity associated with the open cervical approach and provides a wider view and exposure than conventional open surgery. The availability of the porcine model allows the acquisition of the necessary technical skills before introducing this advanced procedure in humans.     

Minimally invasive approach to the cervical spine: a proposal

BACKGROUND and PURPOSE: During the last 3 years, a minimally invasive video-assisted approach for parathyroidectomy and thyroidectomy has been developed. Because of the good exposure of the cervical spine during these procedures, the authors decided to perform an anatomic-radiologic study in order to evaluate which cervical vertebrae could be reached by this minimally invasive approach. PATIENTS and METHODS: Three consenting patients, two undergoing minimally invasive parathyroidectomy and one a conventional operation for C4-C5 disc herniation, were selected for this study. The procedure was carried out through a single 1.5-cm central skin incision above the sternal notch. After opening of the cervical linea alba, dissection was performed under endoscopic vision, without using any CO2 insufflation or trocar. After exposure of the prevertebral fascia, an operative tube was introduced through the cervical incision in order to maintain the operative space without using conventional retractors. RESULTS: Through this operative tube, it was possible to introduce both a 5-mm (or 3-mm) endoscope and the surgical instruments. In our patients, we inserted a 1-mm metal probe to exactly localize during fluoroscopy the vertebrae reached by the dissection (C2-C7). CONCLUSIONS: This study shows the feasibility of an anterior minimally invasive approach to the cervical spine. Although the exact indications have to be verified, a video-assisted approach could add some advantages to the well-known benefits coming from the anterior approaches to the cervical spine, especially in terms of cosmetic results and postoperative course and recovery.     

High anterior cervical approach to the upper cervical spine

BACKGROUND: Surgical exposure of the upper cervical spine is challenging, and optima approaches are subjects of debate. The high anterior cervical approach to the upper cervical spine is a favorable method that provides direct and wide exposure for fusion and anterior decompression of the upper cervical spine. The authors present their experiences with 15 patients in whom fusion and instrumentation on the upper cervical spine were performed via the prevascular extraoral retropharyngeal approach. METHODS: A series of 15 patients who were surgically treated using the high anterior cervical retropharyngeal approach was reviewed. These cases involved a C2 hangman's fracture with significant angulation and translation (11 patients), C2 EDH (1 patient), C2 chordoma (1 patient), C3-4 metastasis (1 patient), and C2-3-4 OPLL (1 patient). RESULTS: Twelve patients underwent C2-3 fusion followed by instrumentation. C2-5 fusion with instrumentation was performed in 2 patients. One patient experienced occipitocervical fusion after anterior removal of a C2 chordoma. A solid fusion was achieved in 13 patients. However, 1 patient needed additional posterior fusion because of fusion failure, and the other died due to ischemic heart disease. There was 1 patient who developed permanent dysphagia related to the hypoglossal nerve and 2 who had transient dysphagia. No complications occurred related to the marginal branch of the facial nerve or submandibular gland. CONCLUSIONS: The high anterior cervical approach is a useful surgical technique for an upper cervical lesion without severe morbidity, which allows direct anterior access to C2 and C3 while allowing extension to the lower cervical spine.     

Minimally invasive approaches to the cervical spine

Minimally invasive approaches and operative techniques are becoming increasingly popular for the treatment of cervical spine disorders. Minimally invasive spine surgery attempts to decrease iatrogenic muscle injury, decrease pain, and speed postoperative recovery with the use of smaller incisions and specialized instruments. This article explains in detail minimally invasive approaches to the posterior spine, the techniques for posterior cervical foraminotomy and arthrodesis via lateral mass screw placement, and anterior cervical foraminotomy. Complications are also discussed. Additionally, illustrated cases are presented detailing the use of minimally invasive surgical techniques.     

内镜下上颈椎前方咽后入路的应用解剖学研究

目的 对上颈椎前路咽后入路进行解剖学研究,为应用内镜行上颈椎前路手术提供解剖学依据.方法 对10具防腐和3具新鲜成人尸体标本进行C臂机下模拟上颈椎前路手术内固定及逐层解剖,测量咽后壁厚度,观察穿刺套管经甲状腺上动脉下方入路时与重要血管神经等结构的相应关系,分析MED下进行上颈椎前路咽后壁手术的安全性.结果 MED套管与甲状腺上血管、神经相邻,而距离舌下神经、舌动脉、舌咽神经等较远.在颈1～2水平咽后壁正中旁开10 mm软组织厚度平均为(5.32±2.14)mm,咽后间隙与椎前间隙之间可以形成较大腔隙,足可以安全放置外径18 mm套管.结论 经内镜下行上颈椎前路咽后手术入路是安全的.     

上位颈椎前路手术咽后人路"窗口"显露技术的临床应用观察

目的:探讨上颈椎前路减压经咽后入路"窗口"显露技术在上颈椎损伤手术中的应用.方法:2000年1月至2008年7月手术治疗上位颈椎损伤患者5例,男4例,女1例;年龄16～68岁,平均35岁.C2椎弓骨折(HangmanⅡ型)2例,C2,3椎间盘突出症2例,C2椎体结核1例.所有患者经高位前方咽后入路舌下神经、喉上神经、咽和颈动脉之间的"窗口"成功获得显露.Hangman骨折复位后行C2,3椎间盘切除椎闻植骨融合内固定.C2,3椎间盘突出症患者行相应椎间盘切除,减压植骨融合内固定.C2椎体结核行病灶清除并植骨等.结果:5例患者均成功在舌下神经、喉上神经、咽和颈动脉之间的"窗口"显露出C1前弓一C3椎体.随访5～26个月,平均13.5个月.无伤口感染,无颈部重要血管神经损伤.患者的神经症状恢复良好,所有患者植骨都获得了融合.结论:前方咽后入路的"窗口"显露技巧可使上颈椎获得理想的显露,创伤小,切口并发症少,有相关经验后也比较安全.     

The anterior retropharyngeal approach to the upper part of the cervical spine

Since 1959, we have used a superior extension of the anterior approach to the cervical spine of Robinson and Smith in a consecutive series of seventeen patients. This approach provided anterior access to the neural elements from the clivus to the body of the third cervical vertebra, without the need for posterior dissection of the carotid sheath or entrance into the hypopharynx or oral cavity. It also provided adequate exposure for the insertion of iliac or fibular strut grafts, which was necessary in thirteen patients. The approach gave excellent exposure for anterior intralesional excision of a tumor in ten patients, marginal excision of an osteochondroma, two corpectomies of the second cervical vertebra combined with removal of the odontoid process, corpectomy of the second cervical vertebra for the treatment of fixed atlanto-axial subluxation, removal of a bullet anterior to the clivus, reduction of a dislocation of the second on the third cervical vertebra secondary to an unstable fracture of the pedicles of the second cervical vertebra, and anterior débridement for treatment of pyogenic vertebral osteomyelitis. In contrast to the reported results of transmucosal approaches to the atlas and axis, there were no infections or iatrogenic neurological deficits of the spine in the present series. Twelve patients who were followed for two years or more had a solid anterior fusion and no subsequent loss of cervical stability. Pain in the neck was relieved in all of the patients who had had a pathological or traumatic fracture.     

上胸椎前方手术入路的解剖及其临床意义

目的研究上胸椎与其毗邻组织结构的解剖关系,为探讨上胸椎前方手术入路提供参考.方法取20具经防腐处理的尸体标本,模拟上胸椎前路手术,部分劈开胸骨,并分别经不同的血管、神经间隙显露椎体,比较不同的血管、神经间隙入路的暴露范围及其优缺点.观察上胸椎毗邻的血管、神经等组织结构的走行及其与椎体的对应关系.结果头臂干外侧间隙入路（头臂干与右头臂静脉、左头臂静脉根部之间的间隙）95%可显露达T3椎体以下,而头臂干内侧间隙入路（气管食道鞘与头臂干、左头臂静脉之间的间隙）只有45%可显露达T3椎体以下.上腔静脉与升主动脉之间的间隙只能在直视下显露T4,并且视野狭小.右喉返神经在T1,2水平从迷走神经发出,绕过锁骨下动脉斜行走向内上,在T1椎体上缘水平附近走向气管食道沟.胸导管75%在T1椎体到T1-2椎间盘水平入左侧静脉角,约50%最高点达T1水平.左头臂静脉55%平T3椎体水平从上腔静脉发出.主动脉弓主干约80%在T3-4椎间盘水平横过椎体.结论头臂干外侧间隙入路操作简单、显露清楚,可以很容易地显露T3和T4椎体;头臂干外侧间隙与头臂干内侧间隙相比,可多显露0.5～1个椎体.但由于迷走神经穿过此间隙并在此发出心支,所以应注意保护迷走神经.在右侧施行T1,2水平手术时易损伤右喉返神经.在采用左侧入路时应注意胸导管的走行,避免损伤胸导管.     

The anterior surgical approach to the cervical spine for intervertebral disc disease

THE ANTERIOR SURGICAL APPROACH to the cervical spine in patients with discogenic compressive pathological findings causing radiculopathy or myelopathy is a commonly performed operation with several technical variations. We describe the normal and pathological anatomy and the techniques of surgical decompression of the dura with autograft fusion, which we have used for the past 35 years.     

借助胸腔镜技术的胸段、上腰段脊柱前路手术

目的探讨胸腔镜辅助胸椎、上腰椎前路手术的适应证 ,单肺或双肺通气的选择以及术中注意事项。方法　应用胸腔镜、骨科常规手术器械或自制的骨科器械 ,在胸腔镜辅助下行病灶清除、脊髓减压、植骨、钢板螺丝钉内固定术。结果　全部病例手术都顺利完成 ,切口均一期愈合 ,随访 3～ 10个月 ,影像学检查显示病灶清除彻底 ,脊髓减压充分 ,除 1例骨折复位、固定后仍有轻度侧方成角畸形外 ,其他病例复位满意、内固定可靠 ,位置良好。结论胸椎、上腰椎疾患 ,不论是否并发脊髓、马尾神经压迫 ,都能在胸腔镜辅助下完成病灶清除术 ,必要时还可进行脊髓减压、脊柱前路植骨、内固定手术。原则上可选择常规气管插管、双肺通气下完成手术。     

Minimally invasive anterior contralateral approach for the treatment of cervical disc herniation

BACKGROUND: During the practice of ipsilateral approach to the offending lesion in anterior simple discectomy, the authors realized that it achieves better surgical exposure of the opposite foraminal area. In addition, it was also realized that routine procedures for better visualization of the foraminal area, such as stripping longus colli muscles, further excising of the anterior longitudinal ligament, or using a spreader, which cause more invasive surgery during the standard anterior approach, are not necessary because the contralateral approach already achieves sufficient exposure of the target foraminal area. OBJECTIVE: Evaluation of the results and effectiveness of this minimal invasive technique in patients with either soft or hard disc herniations. METHODS: Between January 1994 and April 2002, 216 patients underwent anterior contralateral microdiscectomy without fusion for cervical disc herniation at 1 or 2 adjacent levels. Anterior contralateral microdiscectomy is a less invasive technique than standard anterior simple discectomy in which longus colli muscles are not stripped, and the lateral part of annulus fibrosis at the side of intervention and ventrolateral part of it at the opposite side are not removed. In addition, a mini Zenker handheld retractor is used for retraction of paravertebral soft tissues and a spreader is not used during the discectomy procedure. There were 182 patients diagnosed with radiculopathy and 34 patients with myelopathy. Assessments of the neurological status of patients with radiculopathy were done by physical examinations, and of those with myelopathy according to the modified Japanese Orthopaedic Association cervical spine functional assessment scale. These neurological assessments were repeated in the 18th month after surgery. In the follow-up period, the outcomes of surgery were also assessed for all patients in 4 categories, from failure to excellent. RESULTS: Surgery outcomes generally have been good to excellent and none of the patients were made worse by the procedure. The outcomes were significantly better in the radiculopathy and soft disc herniation groups. Other positive outcome factors were short duration and sudden onset of symptoms, normal cervical curvature, and single-level disease. Follow-up radiological studies revealed fibrous healing with normal or slight loss of disc height in 199 (92.1%) patients and total obliteration of the involved disc space representing radiological fusion signs in 13 (6%) patients. The overall complications observed in this study were 2 spontaneous and 2 postinfection collapses of disc level, 1 excessive fibrosis of disc level, and 2 adjacent-level diseases. CONCLUSION: Anterior contralateral microdiscectomy without fusion achieves better exposure for resection of the offending foraminal or far lateral lesions, ventral osteophytes, or a disc fragment under direct microscopic visualization. Collapse and instability of the involved disc level can also be avoided via this less invasive technique.     

上颈椎微创内固定技术的应用研究进展

先天性畸形、肿瘤、感染、创伤及退行性病变等常导致上颈椎失稳而需要内固定手术治疗，不同的发病机制及损伤部位选择的内固定方式也不同，目前固定方式主要有齿状突螺钉内固定、寰枢椎经关节螺钉内固定、枕寰枢螺钉内固定、寰枢椎螺钉-棒内固定、枢椎椎弓根螺钉内固定等。但一些经典的手术方式常需要较大的切口来暴露术区，对软组织的创伤大，术中出血较多，围手术期疼痛较明显。因此各国学者提出了手术创伤更小，安全性更高的手术方式，即微创手术，以期减少手术相关的并发症。目前微创上颈椎内固定技术主要包括主要包括微创前路上颈椎内固定技术（经皮前路齿状突螺钉内固定技术、经皮前路寰枢椎经关节螺钉内固定技术、 经皮前路枕寰枢螺钉内固定技术）和微创后路上颈椎内固定技术（微创后路寰枢椎螺钉-棒内固定技术、经皮后路寰枢椎经关节螺钉内固定技术、经皮枢椎椎弓根螺钉内固定技术）。笔者就微创内固定技术做一综述，为脊柱外科医生提供参考和借鉴。     

Anterior approach to the cervical spine: surgical anatomy

While performing the anterior approach to the cervical vertebral bodies, injury to important anatomic structures in the vicinity of the dissection represents a serious risk. The midportion of the recurrent laryngeal nerve and the external branch of the superior laryngeal nerve are encountered in the anterior approach to the lower cervical spine. The recurrent laryngeal nerve is vulnerable to injury on the right side, especially if ligation of inferior thyroid vessels is performed without paying sufficient attention to the course and position of the nerve, and the external branch of the superior laryngeal nerve is vulnerable to injury during ligature and division of the superior thyroid artery. Avoiding injury to the recurrent laryngeal nerve (especially on the right side) and superior laryngeal nerve is a major consideration in the anterior approach to the lower cervical spine. The sympathetic trunk is situated in close proximity to the medial border of the longus colli at the C6 level (the longus colli diverge laterally, whereas the sympathetic trunk converges medially). The damage leads to the development of Horner's syndrome with its associated ptosis, meiosis, and anhydrosis. Awareness of the regional anatomy of the sympathetic trunk may help in identifying and preserving this important structure while performing anterior cervical surgery or during exposure of the transverse foramen or uncovertebral joint at the lower cervical levels. Finally, the spinal accessory nerve (embedded in fibroadipose tissue in the posterior triangle of the neck) is prone to injury. Its damage will result in an obvious shoulder droop, loss of shoulder elevation, and pain. Prevention of inadvertant injury to the accessory nerve is critical in the neck dissection.     

A surgical approach to the upper thoracic spine

We describe a surgical approach to the upper thoracic spine which allows an adequate exposure of the vertebral bodies from T1 to T3. The approach causes little functional disturbance and is especially useful in older patients with spinal tumours causing spinal cord compression.     

Minimally invasive lateral mass plating in the treatment of posterior cervical trauma: surgical technique

OBJECTIVE: The technique of lateral mass fixation restores the posterior tension band and provides effective stabilization in patients with many types of traumatic injuries. However, postoperative wound pain is not uncommon. The objective of this work is to describe a modified technique of minimally invasive lateral mass plating for cervical spine trauma. METHODS: Patient 1 was a 64-year-old woman who had been in a motor vehicle accident and sustained bilateral C5-C6 facet dislocation with posterior C5-C6 distraction. She was otherwise neurologically intact, and attempts at closed reduction were not successful. Patient 2 was a 16-year-old girl who had also been in a motor vehicle accident but had an incomplete spinal cord injury. She had an unstable burst fracture of C7 with posterior C5-C6 distraction. Both patients underwent anterior cervical fusion followed by staged minimally invasive posterior fusion with good results. A dilator tubular retractor system (METRX) was used to access the bilateral lateral masses through a small midline incision under fluoroscopic guidance. Lateral mass screws were then placed by using a modified Magerl technique, securing two-hole plates on each side onto the lateral masses, performed through the METRX system. We also successfully performed four-level lateral mass plating in a cadaveric cervical spine using a 2-cm skin incision. CONCLUSIONS: We describe successful placement of lateral mass screw and plate constructs with the use of a minimally invasive approach by means of a tubular dilator retractor system. This approach preserves the integrity of the muscles and ligaments that maintain the posterior tension band of the cervical spine.