Chirurgische Aspekte der rheumatischen Halswirbelsäule

Approximately 20% percent of the patients with rheumatoid arthritis show pathology in the cervical spine, mainly in the atlantoaxial segment. The translational instability between axis and atlas might be painful and leads in the long term to myelopathic changes due to chronic traumatization of the myelon. Ongoing osseous resorption of the lateral masses of the atlas cause upward migration of the dens into the foramen magnum. In the subaxial cervical spine, the inflammatory process causes instability and deformity. Neck pain is the most common indication for surgery, but neurological symptoms with myelopathy or radicular deficits might be the primary cause for surgery. It has to be kept in mind that clinical assessment in rheumatoid patients might be extremely difficult since previous surgeries on various articulations of the extremities make interpretation of clinical findings difficult. Neurophysiological investigation is suitable to obtain objective results. Stabilization of the atlantoaxial segment is the most common procedure for treatment of atlantoaxial instability. It is performed by screw fixation technique from a posterior approach. In case of severe occipitocervical dislocation, the fixation has to be extended to the occiput. Persistent dislocation or compression by the dislocated dens has to be treated by transoral decompression. In the subaxial spine, instabilities may be treated by posterior plate fixation with lateral mass screws or pedicle screws. Concomitant narrowing of the spinal canal should be approached by anterior decompression with corpectomy and/or posterior laminectomy. The timing of surgery in rheumatoid patients is crucial to obtain satisfactory clinical results.     

Rheumatoid arthritis of the cervical spine. Current concepts for diagnosis and therapy

The involvement of the cervical spine in patients with rheumatoid arthritis (RA) is common,and has recently received growing attention. In the early stage of the disease, there is an isolated atlantoaxial subluxation (AAS). With further progression, osseous destruction of the joints can lead to vertical instability. While the involvement of the middle and lower cervical spine can cause a subaxial instability, neurological deficits can occur at any time. The onset of cervical myelopathy in patients with RA is often missed because of additional problems related to the hands and feet. If patients show clear symptoms of cervical myelopathy, the progression of the disease cannot be stopped by conservative treatment. Other indications for operative treatment are severe pain and radiological evidence of progressive instability. In the case of an isolated AAS, fusion can be restricted to the C1/C2 segment. If there is evidence for vertical or subaxial instability, an occipitocervical fusion has to be performed. To avoid instability adjacent to the fusion, the surgeon must check for signs of potential subaxial instability. If this is the case, fusion should include the entire cervical spine. Additional transoral decompression may be necessary when there is persistent retrodental pannus or osseous compression by an irreducible transverse dislocation or cranial migration of the dens. Non-ambulatory myelopathic patients are more likely to present severe surgical complications with limited prospects of functional recovery. Therefore, it is important to avoid the development of severe cervical myelopathy by early surgical intervention.     

Surgical procedures on the cervical spine in polyarthritis.

Summary Patients with rheumatoid arthritis suffer frequently from instabilities and deformities of the cervical spine which require surgical treatment. The most frequent indication for surgery represents the transverse atlantoaxial instability. As long the atlantoaxial instability remains reducible in extension a limited posterior exposure and screw fixation is adequate. Only situations with fixed dislocations and signs of myelopathy require anterior transoral decompression with simultaneous occipitocervical fusion. In the lower cervical spine, kyphotic deformities require anterior decompression and posterior stabilization in the case of electrophysiologically confirmed neurological deficits. A combined procedure with anterior vertebrectomy and decompression and posterior plate fixation is indicated since the poor bone quality rarely allows anterior stable fixation.      

One stage anterior-posterior approach for traumatic atlantoaxial instability combined with subaxial cervical spinal cord injury

Objectives

To explore the clinical features of traumatic atlantoaxial instability combined with subaxial cervical spinal cord injury (CSCI), and to analyze the feasibility, indication and therapeutic effects of anterior-posterior approach in such cases.

Methods

From March 2004 to September 2009, 16 cases with this trauma were admitted and surgically treated in our department. Before surgery, skull traction was performed. Posterior atlantoaxial pedicle screw internal fixation and bone graft fusion were conducted to manage traumatic atlantoaxial instability. As for subaxial CSCI, anterior cervical corpectomy or discectomy decompression, bone grafting and internal fixation with steel plates were applied.

Results

All operations were successful. The average operation time was 3 hours and operative blood loss 400 ml. Satisfactory reduction of both the upper and lower cervical spine and complete decompression were achieved. All patients were followed up for 12 to 36 months. Their clinical symptoms were improved by various levels. The Japanese Orthopaedic Association (JOA) scores ranged from 10 to 16 one year postoperatively, 13.95±2.06 on average (improvement rate=70.10%). X-rays, spiral CT and MRI confirmed normal cervical alignments, complete decompression and fine implants' position. There was no breakage or loosening of screws, nor exodus of titanium mesh or implanted bone blocks. The grafted bone achieved fusion 3-6 months postoperatively and no atlantoaxial instability was observed.

Conclusions

Traumatic atlantoaxial instability may combine with subaxial CSCI, misdiagnosis of which should be especially alerted and avoided. For severe cases, one stage anterior-posterior approach to decompress the upper and lower cervical spine, together with reposition, bone grafting and fusion, as well as internal fixation can immediately restore the normal alignments and stability of the cervical spine and effectively improve the spinal nervous function, thus being an ideal approach.     

Fusion of the cervical spine for instability

The orthopedic and neurosurgical literature is neither clear nor consistent in describing an unstable cervical spine. In a series of 25 patients treated by arthrodesis of the cervical spine for instability, 12 had Gallie fusions at the atlantoaxial level. Eight of those fusions were performed for rheumatoid arthritis. In three patients persistent subluxation of the atlas on the axis occurred because the wires were not fully tightened in areas of poor-quality bone. Stable fixation with relief of symptoms was achieved in all patients who had fusions at the subaxial level. Several of these patients had had prolonged nonsurgical treatment. With rheumatoid bone of poor quality, the surgeon must be very careful to tighten the wires only enough to secure a stable reduction for treatment of subaxial cervical instability. Since stability achieved by healing of soft tissue is generally unreliable, prolonged periods of nonsurgical treatment are not justified for traumatic instability.     

Die atlantoaxiale Kyphose

Atlantoaxial kyphosis (AAK) is a rare sagittal deformity of the occiptoatlantoaxial junction. It is defined as a subgroup of anterior translatory atlantoaxial instability. AAK is a symptom of several ligamentours or bony disorders of the craniocervical junction; however, rheumatoid arthritis and trauma are the most common causes for AAK. AAK can be diagnosed on lateral radiographic views of the upper cervical spine if the angle between McGregor's line and the atlas plane is less than-15 degrees or the atlas-axis angle is greater 105 degrees. Treatment modalities for AAK depend on the ability to reduce the deformity. If closed reduction is achieved, posterior atlantoaxial fusion by sublaminar wiring according to Brooks or transarticular screw fixation according to Magerl are possible choices. Irreducible AAK can be treated with a combined transoral decompression, anterior plating according to Harms, and posterior wiring according to Brooks. This staged therapy for AAK was successful in our rheumatoid patient population with AAK.     

前路松解复位后路内固定治疗难复性寰枢关节脱位

目的：探讨难复性寰枢关节脱位的手术治疗方法。方法：对3例难复性寰椎前脱位的病例经口咽入路切断颈长肌、头长肌、前纵韧带和寰枢侧块关节囊，施行松解复位术，同期行后方固定植骨融合术。后方固定方法包括：经寰枢侧块关节螺钉固定、寰枢侧块钉板固定和借助于枢椎椎弓根螺钉的枕颈固定。结果：3例均获得了解剖复位和植骨融合。结论：经口咽入路的寰枢关节松解复位术可使难复性脱位的寰枢关节获得充分复位，松解复位术是一种安全、有效的治疗方法。     

Cervical spine instability in rheumatoid patients having total hip or knee arthroplasty

The records and roentgenographs of 113 rheumatoid patients treated by total hip or knee arthroplasty were analyzed retrospectively. The cervical spine roentgenographs were evaluated for significant atlantoaxial subluxation, atlantoaxial impaction, and subaxial subluxation. One or more of these findings were present in 69 (61%) of the patients. Thirty-five of the 69 (50%) with roentgenographically documented cervical spine instability had no signs or symptoms of instability at the time of admission for joint replacement. This high incidence of cervical spine instability in a select population of rheumatoid patients emphasizes the importance of preoperative evaluation of the cervical spine including flexion and extension lateral roentgenographs.     

寰枢椎脱位后路螺钉固定方法的临床选择

目的 探讨寰枢椎脱位后路钉棒固定术中寰椎螺钉和枢椎螺钉固定方法 的临床选择.方法 对2002 年11 月至2011 年12 月广州军区广州总医院收治的228 例可复性和23 例难复性寰枢椎脱位患者,术前进行置钉可行性和复位可能性评估,针对性地选择寰椎和枢椎的后路螺钉固定方法,进行寰枢椎后路钉棒固定治疗.结果 251 例患者均行钉棒固定并获得满意复位.寰椎螺钉固定采用椎弓根螺钉403 枚、部分经椎弓根螺钉77 枚、侧块螺钉22 枚;枢椎螺钉固定采用椎弓根螺钉437 枚、椎板螺钉56 枚、侧块螺钉9 枚.术中未发生椎动脉、脊髓损伤.237 例患者获得随访,随访时间4～38 个月,平均随访时间13 个月.230 例患者获骨性融合;6例为纤维愈合,动力位片（均随访2 年以上）未见复发脱位;另1 例为假关节未融合并双侧枢椎椎弓根螺钉松动,行后路翻修手术治愈.结论 根据寰枢椎脱位的复位难易程度和个体解剖特点灵活选择寰椎和枢椎不同的后路螺钉固定方法,扩大了寰枢椎后路钉棒固定技术的适用范围,提高了手术安全性和成功率.     

Posterior fixation and fusion with atlas pedicle screw system for upper cervical diseases

Objective： To evaluate the feasibility, safety and efficacy of atlas pedicle screws system fixation and fusion for the treatment of upper cervical diseases.
Methods： Twenty-three consecutive patients with upper cervical disorders requiring stabilization, including 19 cases of atlantoaxial dislocation （4 congenital odontoid disconnections, 6 old odontoid fractures, 4 fresh odontoid fractures of Aderson Ⅱ C, 3 ruptures of the C1 transverse ligament, and 2 fractures of C1）, 2 cases of C2 tumor （instability after the resection of the tumors）, and 2 giant neurilemomas of C2-C3（instability after resection of the tumors）, were treated by posterior fixation and fusion with the atlas pedicle screw system, in which the screws were inserted through the posterior arch of C1. The operative time, bleeding volume and complications were reported. All patients were immobilized without external fixation or with rigid cervical collars for 1-3 months. All patients were followed up and evaluated with radiographs and CT.
Results： In the 23 patients, 46 C1 pedicle screws, 42 C2 pedicle screws and 6 lower cervical lateral mass screws and 2 lower cervical pedicle screws were placed. The mean operative time and bleeding volume was 2.7 hours and 490 ml respectively. No intraoperative complications were directly related to surgical technique. No neurological, vascular or infective complications were encountered. All patients were followed up for 3-36 months （average 15 months）. Firm bony fusion was documented in all patients after 3-6 months. One patient with atlas fracture showed anterior occipitocervical fusion. There was no implant failure. Conclusions： Posterior fixation and fusion of the atlas pedicle screw system is feasible and safe for the treatment of upper cervical diseases, and may be applicable to a larger number of patients.     

颈后路手术治疗类风湿性寰枢椎不稳

目的：对类风湿性寰枢椎不稳患者颈后路植骨融合、内固定手术进行探讨。方法：对21例类风湿性寰枢椎不稳患者采用颈后路植骨融合、内固定手术，其中7例可复性寰枢椎半脱位行寰枢椎间植骨钛缆或Apofix固定术；14例难以复位者行枕颈间植骨cervifix固定术。结果：随访6～28个月(平均18个月)。21例均无并发症发生，X线显示均获骨性融合，19例患者神经功能获不同程度改善，2例虽无改善但无神经损害发展。结论：颈后路植骨融合、内固定术可为类风湿性寰枢椎不稳的患者提供牢固的融合固定，且以早期手术为佳。     

Occipitocervical fusion in patients with rheumatoid arthritis

Instability and deformity of the cervical spine caused by rheumatoid arthritis is a well known entity. Operative intervention is indicated for patients with progressive deformity and when pain is resistant to conservative treatment. In a series of 39 patients who underwent posterior occipitocervical fusion with a Y plate, 22 patients were observed clinically and radiographically at average 41.5 months after surgery. In 35 of the 39 patients the main indication for surgery was pain, and in 30 of the 39 patients additional neurologic deficit (radiculopathy or myelopathy) was present. Thirty-one of the 39 patients had atlantoaxial instability. The atlantoaxial instability was associated with cranial migration of the dens in 19 patients. According to the classification of Conaty and Mongan 77.3% patients had satisfactory results and 22.7% had unsatisfactory results. Of the 30 patients with neurologic deficit, nine patients had a significant improvement. No patient had a worse result after surgery. Solid fusion was seen in all 22 patients at followup. Seven patients experienced complications directly related to the surgical procedure. Posterior fixation combined with anterior decompression in the presence of spinal stenosis represents a useful and safe method to treat instability and deformity caused by rheumatoid arthritis. Early surgical procedures may reduce the complication rate.     

Principles of surgical treatment of the cervical spine in rheumatoid arthritis

Summary About 20% of patients with rheumatoid arthritis complain about neck problems based on instability and deformity. As a consequence, pain, myelopathy, and severe neurological deficit may occur. Results reported in the literature were not encouraging as regards surgical decompression and stabilization. However, new surgical techniques allow a more aggressive strategy towards the complex problem of the instable cervical spine in rheumatoid arthritis. The most frequent instability of C1/2 can be stabilized by a posterior atlantoaxial screw fixation, a three-dimensional multidirectional construct with few complications. For the inclusion of the occiput into the fusion and the extension of the fusion down to the lower cervical spine, a titanium Y-plate is presented as a successful implant. While through a posterior approach, stability may be achieved, decompression is preferably done by anterior diskectomy or vertebrectomy. Encouraging results with a significant recovery of neurological deficits justify an early intervention in cases of instability of the cervical spine in rheumatoid arthritis.     

高位颈椎的前路手术治疗

目的观察高位颈椎前路手术的临床效果,方法本组15例．男10例,女5例．年龄12—67岁。C1,2椎体结核3例．Hangman 7例,先天性齿状突不连伴难复性环椎脱位3例,齿状突骨折2例。本组经高位前方咽后入路显露C2-3,椎体结核患者行病灶清除术．先天性齿状突不连者行前路松解复位．后路环枢融合;Hangman骨折。复位后行C2,3椎间植骨融合术．放自锁钛板内固定,齿状突骨折行前路中空螺钉内固定。结果15例患者均成功地显露C1前弓至C3椎体,并完成病灶清除、复位、减压融合内固定：无颈部重要血管神经损伤,无伤口感染．9例不全瘫有部分恢复。结论高位前方咽后入路可充分显露上颈椎．高位颈椎前路术式能有效复位、减压和稳定,并可最大程度重建颈椎生理功能。     

Atlanto-axial rotation dislocation (case report)

The authors present a female patient 45 years old, who had a car accident as a driver of a passenger car. Her car was hit from the left side by another car and the women hurt her head, neck and left shoulder. Due to pain in the region of the head and neck she was taken to the respective surgical out-patient department where they diagnosed the concussion of the brain of II degree and distortion of the cervical spine. The patient was treated conservatively by bed rest with the cervical spine fixed in the soft Schanz collar. After ten days she was discharged from the hospital and further followed up by a neurologist in the out-patient department. She underwent physical therapy focussed on the relaxation of muscles in the region of the cervical spine. Due to persisting pain in the region of upper cervical spine the patient was sent to the department of the first author six weeks after the injury. On clinical examination the head was inclined to the right and rotated to the left with pain in the region of the occipitocervical passage. Radiographs were made in the lateral and Sandberg projection. In the lateral projection the atlantodental distance was normal, the Sandberg projection showed an evidently asymmetrical location of the dens between the lateral masses of the atlas, asymmetrical size of the lateral masses and inclination of the head to the left. These basic projections alone showed an evident rotational atlantoaxial dislocation of I degree according to Fielding. The authors further added CT examination which showed rotation of C1 against C2 and asymmetrical location of the dens without dislocation from the anterior arch of the atlas. A conservative physical therapy was not successful and the patient felt worse. Twelve months after the injury a pre-operative traction by Glisson sling was introduced for five days with a gradual weight bearing up to 5 kg. A reduction followed from the dorsal approach and fixation of C1-C2 after Magerl combined with Gallie technique. The surgery was without complications and the post-operative radiographs showed a good position of the C1-C2 complex and a correct insertion of screws through atlantoaxial joints. The patient wore for six weeks a Philadelphia collar and another six weeks the Schanz collar. Standard and functional radiographs in flexion and extension made 12 weeks after the surgery showed bone bridging between C1-C2 arches and a stable atlantoaxial fusion. At the check one year after the surgery the patient had a limited rotation of the head by 25%, however, she was without pain and the inclination and rotation of the head was compensated. In the authors' view the use of Magerl technique of C1-C2 fixation is possible in case of a rotational atlantoaxial dislocation but difficult with regard to the changed anatomical conditions.     

Endoscopic transcervical anterior release and posterior fixation in the treatment of irreducible vertical atlantoaxial dislocation

Vertical atlantoaxial dislocation is a type of atlantoaxial instability with upper cervical spinal cord compression. The transoral ondontoid resection with posterior fixation is the gold standard for ventral decompression. Results are satisfying though surgery can be challenging due to its invasiveness. The endoscopic transcervical anterior release could provide sufficient ventral decompression with less collateral damage. In the illustrative case, anatomic reduction was achieved with significant improvement in neurological function and radiographic parameters. Endoscopic transcervical anterior release and posterior fixation appears to be a viable and interesting alternative for the treatment of vertical atlantoaxial dislocation in properly selected individuals, and its implementation could significantly reduce the post-surgical complications.     

难复性寰枢椎脱位的外科治疗

目的 探讨难复性寰枢椎脱位治疗中寰枢椎松解方法的选择,应用椎弓根螺钉钉棒系统复位、固定及融合的疗效.方法 对2003年12月至2008年6月收治的19例难复性寰枢椎脱位患者的病例资料进行同顾性分析.男15例,女4例;年龄11～66岁,平均41.5岁.寰椎前脱位15例,寰椎后脱位4例.14例有明确外伤史.所有患者均表现为颈部疼痛、活动受限,14例有四肢麻木、行走不稳等颈髓压迫症状.术前常规行X线、MR和CT三维重建检查,评估寰椎移位及旋转程度.根据脱位类型及移位程度选择前路和(或)后路对寰枢椎进行松解,在持续颅骨牵引下利用椎弓根螺钉进行寰椎复位、固定及髂骨块植骨融合.术后头-颈-胸支具保护12周.结果 所有患者均获随访,随访时间10～60个月,平均26.4个月.患者颈部疼痛缓解,14例存在神经压迫的患者神经功能好转,脊髓ASIA残损分级提高.平均4.5个月植骨愈合.术前寰椎移位5～13mm,平均(8.7±2.6)mm,术后平均(2.6±1.2)mm;术前寰椎旋转0°～55°,平均(17.3°±5.8°),术后平均(5.0°±2.4°);两者均较术前下降,差异有统计学意义(P<0.05).无神经、椎动脉损伤及内同定失败、切口感染等并发症.结论 对难复性寰枢椎脱位应根据脱位类型和移位程度选择相应的寰枢椎松解方法.良好的寰枢椎松解、复位结合后路椎弓根螺钉钉棒固定、髂骨块植骨融合是治疗难复性寰枢椎脱位较好的方法.     

枢椎椎板螺钉在上颈椎后路固定术中的应用

目的探讨枢椎椎板螺钉固定术应用于上颈椎后路融合内固定术中的可行性。方法回顾性分析本院2012年1月—2014年12月在上颈椎后路融合固定术中采用枢椎椎板螺钉固定的19例患者资料,术中根据枢椎椎弓根是否存在缺如、细小等情况,选择置入双侧枢椎椎板螺钉或单侧枢椎椎板螺钉并对侧椎弓根螺钉,联合枕骨板螺钉和/或寰椎侧块螺钉。15例上颈椎畸形患者均有不同程度脊髓功能损害表现,日本骨科学会(JOA)评分为5~15分,平均11.5分。4例外伤性寰枢椎骨折患者有后颈部疼痛及活动障碍,疼痛视觉模拟量表(VAS)评分为2~7分,平均4.5分。术后复查患者影像学资料,观察内固定位置及植骨融合情况。结果所有手术顺利完成,未发生椎动脉、脊髓等损伤。术后复查CT,显示所有枢椎椎板螺钉位置良好,均未突破内侧皮质骨。随访时X线、CT示螺钉位置良好,无松动及断钉。所有患者术后12个月植骨均融合,上颈椎畸形患者神经功能均有不同程度改善,JOA评分为13~17分,平均15.3分。外伤性寰枢椎骨折患者颈部疼痛及活动障碍明显改善,VAS评分为0~2分,平均1.0分。结论枢椎椎板螺钉固定在上颈椎后路固定手术中方法简单安全、效果良好,对于无法行枢椎椎弓根螺钉固定的患者,枢椎椎板螺钉固定是一种安全有效的替代方法。     

Atlantoaxial fixation using the polyaxial screw–rod system

The aim of this study is to evaluate the first results of the atlantoaxial fixation using polyaxial screw–rod system. Twenty-eight patients followed-up 12–29 months (average 17.1 months) were included in this study. The average age was 59.5 years (range 23–89 years). The atlantoaxial fusion was employed in 20 patients for an acute injury to the upper cervical spine, in 1 patient with rheumatoid arthritis for atlantoaxial vertical instability, in 1 patient for C1–C2 osteoarthritis, in 2 patients for malunion of the fractured dens. Temporary fixation was applied in two patients for type III displaced fractures of the dens and in two patients for the atlantoaxial rotatory dislocation. Retrospectively, we evaluated operative time, intraoperative bleeding and the interval of X-ray exposure. The resulting condition was subjectively evaluated by patients. We evaluated also the placement, direction and length of the screws. Fusion or stability in the temporary fixation was evaluated on radiographs taken at 3, 6, 12 weeks and 6 and 12 months after the surgery. As concerns complications, intraoperatively we monitored injury of the nerve structures and the vertebral artery. Monitoring of postoperative complications was focused on delayed healing of the wound, breaking or loosening of screws and development of malunion. Operative time ranged from 35 to 155 min, (average 83 min). Intraoperative blood loss ranged from 50 to 1,500 ml (average 540 ml). The image intensifier was used for a period of 24 s to 2 min 36 s (average 1 min 6 s). Within the postoperative evaluation, four patients complained of paresthesia in the region innervated by the greater occipital nerve. A total of 56 screws were inserted into C1, their length ranged from 26 to 34 mm (average, 30.8 mm). All screws were positioned correctly in the C1 lateral mass. Another 56 screws were inserted into C2. Their length ranged from 28 to 36 mm (average 31.4 mm). Three screws were malpositioned: one screw perforated the spinal canal and two screws protruded into the vertebral artery canal. C1–C2 stability was achieved in all patients 12 weeks after the surgery. No clinically manifested injury of the vertebral artery or nerve structures was observed in any of these cases. As for postoperative complications, we recorded wound dehiscence in one patient. The Harms C1–C2 fixation is a very effective method of stabilizing the atlantoaxial complex. The possibility of a temporary fixation without damage to the atlantoaxial joints and of reduction after the screws and rods had been inserted is quite unique.     

Complications of transpedicular screw fixation in the cervical spine

Today, posterior stabilization of the cervical spine is most frequently performed by lateral mass screws or spinous process wiring. These techniques do not always provide sufficient stability, and anterior fusion procedures are added secondarily. Recently, transpedicular screw fixation of the cervical spine has been introduced to provide a one-stage stable posterior fixation. The aim of the present prospective study is to examine if cervical pedicle screw fixation can be done by low risk and to identify potential risk factors associated with this technique. All patients stabilized by cervical transpedicular screw fixation between 1999 and 2002 were included. Cervical disorders included multisegmental degenerative instability with cervical myelopathy in 16 patients, segmental instability caused by rheumatoid arthritis in three, trauma in five and instability caused by infection in two patients. In most cases additional decompression of the spinal cord and bone graft placement were performed. Pre-operative and post-operative CT-scans (2-mm cuts) and plain X-rays served to determine changes in alignment and the position of the screws. Clinical outcome was assessed in all cases. Ninety-four cervical pedicle screws were implanted in 26 patients, most frequently at the C3 (26 screws) and C4 levels (19 screws). Radiologically 66 screws (70%) were placed correctly (maximal breach 1 mm) whereas 20 screws (21%) were misplaced with reduction of mechanical strength, slight narrowing of the vertebral artery canal (<25%) or the lateral recess without compression of neural structures. However, these misplacements were asymptomatic in all cases. Another eight screws (9%) had a critical breach. Four of them showed a narrowing of the vertebral artery canal of more then 25%, in all cases without vascular problems. Three screws passed through the intervertebral foramen, causing temporary paresis in one case and a new sensory loss in another. In the latter patient revision surgery was performed. The screw was loosened and had to be corrected. The only statistically significant risk factor was the level of surgery: all critical breaches were seen from C3 to C5. Percutaneous application of the screws reduced the risk for misplacement, although this finding was not statistically significant. There was also a remarkable learning curve. Instrumentation with cervical transpedicular screws results in very stable fixation. However, with the use of new techniques like percutaneous screw application or computerized image guidance there remains a risk for damaging nerve roots or the vertebral artery. This technique should be reserved for highly selected patients with clear indications and to highly experienced spine surgeons.