颈1-2关节突间隙螺钉固定融合治疗寰枢椎损伤及不稳

目的：探讨应用经C1－2关节突间隙螺钉固定技术治疗寰枢椎病变的可行性及临床疗效。方法：自2000年4月－2002年4月应用后路经C1－2关节突间隙螺钉内固定技术治疗C2双侧椎弓骨折3例，陈旧性齿状突骨折1例，寰枢椎不稳1例，观察术后寰枢椎的稳定性、植骨融合率及颈椎活动度。结果：5例病人术中无神经及血管损伤等并发症，术后即刻获得稳定，经4－20个月随访，均获得骨性愈合，螺钉无松动、退出及断裂，颈椎旋转活动度平均丧失35．72％。结论：经C1－2关节突间隙螺钉固定技术在治疗寰枢椎疾病中是安全有效的，为重建寰枢椎间稳定提供了一种新的内固定方法。     

Posterior C1-2 fusion using a polyaxial screw/rod system for os odontoideum with bilateral persistence of the first intersegmental artery

The authors report the case of a patient with os odontoideum, myelopathy secondary to atlantoaxial instability, and bilaterally persistent first intersegmental artery at the craniovertebral junction. Instead of occipitocervical fusion, C1-2 posterior fusion was performed using a polyaxial screw/rod system. The information obtained from 3D CT angiography studies may highlight the potential risk of vertebral artery injury in advance and reduce the risk of an intraoperative vertebral artery injury. In addition, C-1 lateral mass screw placement may be a safe procedure for cases of atlantoaxial subluxation in which there are persistent C-1 intersegmental arteries.     

Modified Gallie technique versus transarticular screw fixation in C1-C2 fusion

The effectiveness of a modified Gallie technique versus Magerl and Seeman transarticular screw fixation was compared in the management of 27 patients with symptomatic atlantoaxial instability. Twelve patients were treated using a modified Gallie technique and postoperative halo vest immobilization. Atlantoaxial arthrodesis occurred in seven (58%) patients, stable fibrous union occurred in one patient, and pseudarthrosis with recurrent instability developed in four (33%) patients. Average followup was 6.9 years. All 15 patients treated using Magerl and Seeman transarticular screw fixation and postoperative soft collar immobilization had atlantoaxial arthrodesis develop. Average duration of followup was 4 years. One patient sustained vertebral artery injury during preparation for screw placement. Magerl and Seeman transarticular screw fixation provides stability and more reliably produces atlantoaxial arthrodesis than the Gallie technique provides in patients with atlantoaxial instability without the need for rigid postoperative bracing. Potential for vertebral artery exists despite apparent accurate screw placement. To ensure that safe transarticular screw placement is possible, preoperative fine cut axial computed tomography with reconstructions is required to assess vertebral artery position and C2 isthmus anatomy. A proportion of patients have anatomy unsuitable for screw placement. Traditional wiring techniques are indicated in these patients.     

Posterior atlanto-axial fixation with polyaxial C1 lateral mass screws and C2 pars screws

Purpose  C1-C2 instability or painful osteoarthritis are recognised indications for posterior atlanto-axial fixation. In the traditional trans-articular C1-C2 screw fixation, up to 20% of patients cannot have safe placement of bilateral screws in the event of a medially located vertebral artery and a straight screw trajectory in the sagittal plane. The more recently developed C1-C2 fixation technique with individual C1 lateral mass screws and converging C2 pars screws can be employed in case of a medially located vertebral artery and has comparable biomechanical strength. This is a prospective observational study to investigate the advantages, the safety, and the drawbacks of posterior atlanto-axial fixation with polyaxial C1 lateral mass screws and C2 pars screws. Methods  Twelve consecutive patients with C1-2 instability (n = 11) and painful osteoarthritis (n = 1) underwent a posterior atlanto-axial fixation with polyaxial C1 lateral mass screws and C2 pars screws. The average follow-up was 16 months and all patients reached the 12-month follow-up. Findings  No hardware failure occurred in any of the patients. Correct screw placement and construct stability was found in all 12 patients (100%) at 6 and 12 months after surgery. Mean neck pain on a visual analogue scale (VAS) was 2.1 at 6 months and 2.0 at 12 months. Only transient complications were observed: one patient presented with progressive intestinal herniation through the iliac crest scar; one suffered from severe pain at the posterior iliac crest for 3 months and three patients complained of annoying pain/dysaesthesia in the C2 dermatome for 3–6 months after surgery. Conclusion  This study confirms that posterior atlanto-axial fixation with polyaxial C1 lateral mass screws and C2 pars screws is a safe and effective surgical option in the treatment of atlanto-axial instability or painful osteoarthritis.     

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.     

C1-C2 transarticular screw fixation: technical aspects.

OBJECTIVE: I review posterior atlantoaxial fusion with transarticular screw fixation, including indications, complications, and operative technique, emphasizing my experience. METHODS: The indications for C1-C2 transarticular screw fixation include traumatic injuries to the atlantoaxial complex, instability resulting from inflammatory disease (rheumatoid arthritis), and congenital abnormalities (os odontoideum). All patients underwent stabilization using cannulated C1-C2 transfacetal screws by the method described by Magerl. Supplemental interspinous fusion with bicortical autologous iliac crest graft and titanium cable was used to restore the posterior tension band by use of the method described by Sonntag's group. Preoperatively, all patients underwent imaging with plain radiographs, magnetic resonance imaging, and axial computed tomography. Patients were maintained in a rigid cervical orthosis postoperatively. RESULTS: Measures used to improve safety and efficacy include patient positioning, fluoroscopic guidance, preoperative magnetic resonance imaging, axial computed tomography, and open reduction of C1-C2 subluxation before screw passage. In this series of 75 patients, fusion was obtained in 72 patients (96%). There were no instances of vertebral artery injury, errant screw placement, instrumentation failure, dural laceration, spinal cord injury, or hypoglossal nerve injury. CONCLUSION: C1-C2 transarticular screw fixation with a posterior tension band construct provides excellent fusion rates with few perioperative complications. Preoperative imaging and meticulous surgical technique improve outcomes.     

Anterior C1-C2 screw fixation and bony fusion through an anterior retropharyngeal approach

We present a case that demonstrates an occasion where an alternative method of C1-C2 fusion may be used when a posterior approach limited to the atlantoaxial level is not desirable. A 22-year-old man presented with a symptomatic nonunited Brooks posterior atlantoaxial fusion following a chronically displaced type II odontoid fracture with a two-part fracture of the posterior arch of C1. An anterior retropharyngeal approach was used to perform an anterior C1-C2 fusion with screw fixation. The surgical technique, as well as the merits and indications of this infrequently used procedure, are discussed.     

Posterior lumbar interbody fusion using one diagonal fusion cage with transpedicular screw/rod fixation

Posterior lumbar interbody fusion (PLIF) using threaded cages has gained wide popularity for lumbosacral spinal disease. Our biomechanical tests showed that PLIF using a single diagonal cage with unilateral facetectomy does add a little to spinal stability and provides equal or even higher postoperative stability than PLIF using two posterior cages with bilateral facetectomy. Studies also demonstrated that cages placed using a posterior approach did not cause the same increase in spinal stiffness seen with pedicle screw instrumentation, and we concluded that cages should not be used posteriorly without other forms of fixation. On the other hand, placement of two cages using a posterior approach does have the disadvantage of risk to the bilateral nerve roots. We therefore performed a prospective study to determine whether PLIF can be accomplished by utilizing a single diagonal fusion cage with the application of supplemental transpedicular screw/rod instrumentation. Twenty-seven patients underwent a PLIF using one single fusion cage (BAK, Sulzer Spine-Tech, Minneapolis, MN, USA) inserted posterolaterally and oriented anteromedially on the symptomatic side with unilateral facetectomy and at the same level supplemental fixation with a transpedicular screw/rod system. The internal fixation systems included 12 SOCON spinal systems (Aesculap AG, Germany) and 15 TSRH spinal systems (Medtronic Sofamor Danek, USA). The inclusion criteria were grade 1 to 2 lumbar isthmic spondylolisthesis, lumbar degenerative spondylolisthesis, and recurrent lumbar disc herniations with instability. Patients had at least 1 year of low back pain and/or unilateral sciatica and a severely restricted functional ability in individuals aged 28-55 years. Patients with more than grade 2 spondylolisthesis or adjacent-level degeneration were excluded from the study. Patients were clinically assessed prior to surgery by an independent assessor; they were then reassessed at 1, 3, 6, 12, 18, and 24 months postoperatively by the same assessor and put into four categories: excellent, good, fair, and poor. Operative time, blood loss, hospital expense, and complications were also recorded. All patients achieved successful radiographic fusion at 2 years, and this was achieved at 1 year in 25 out of 27 patients. At 2 years, clinical results were excellent in 15 patients, good in 10, fair in 1, and poor in 1. Regarding complications, one patient had a postoperative motor and sensory deficit of the nerve root. Reoperation was required in one patient due to migration of pedicle screws. No implant fractures or deformities occurred in any of the patients. PLIF using diagonal insertion of a single threaded cage with supplemental transpedicular screw/rod instrumentation enables sufficient decompression and solid interbody fusion to be achieved with minimal invasion of the posterior spinal elements. It is a clinically safer, easier, and more economical means of accomplishing PLIF.     

后路经关节螺钉固定颗粒状植骨融合治疗寰枢关节不稳定

目的:探讨后路经C1、C2侧块关节螺钉固定、颗粒状松质骨植骨行寰枢关节融合治疗寰枢关节不稳的效果。方法:自1999年12月~2003年4月对58例因齿状突不连、寰椎横韧带断裂或松弛导致寰枢关节不稳定的病例施行了后路经C1、C2侧块关节的螺钉固定术,然后在C1、C2后弓间植入颗粒状松质骨。术中不用钛缆固定寰椎后弓与枢椎棘突。术后不需任何外固定。结果:无手术中损伤脊髓和椎动脉的病例。49例获得随访,时间6个月～3年10个月,平均20个月,全部获得了骨性融合。结论:当寰枢关节不稳定时用两枚螺钉由后路经C1、C2侧块关节固定即可起到足够的稳定作用;在C1、C2后弓间植入颗粒状松质骨可获得很高的融合率。     

Augmentation of occipitocervical contoured rod fixation with C1-C2 transarticular screws.

BACKGROUND CONTEXT: The technique of occipitocervical fusion using a threaded contoured rod attached with sublaminar wires to the occiput and upper cervical vertebrae is widely used throughout the world and has been clinically proven to provide effective fixation of the destabilized spine. However, this system has some disadvantages in maintaining stability, especially at C1-C2 because of the large amount of axial rotation at this level. In some clinical situations such as fracture of the C1 lamina, C1 laminectomy, and excessively lordotic curvature, it is not always possible to wire C1 directly into the construct. In such cases, combination of other stabilization methods that include C1 indirectly can be used to achieve a reliable posterior internal fixation. PURPOSE: Primarily, to evaluate whether a contoured rod construct in which C1 is indirectly included using C1-C2 transarticular screws is biomechanically equivalent to a standard, fully wired contoured rod construct. Secondarily, to evaluate the biomechanical benefit of adding C1-C2 transarticular screws to a fully wired contoured rod construct. STUDY DESIGN: Repeated-measures nondestructive in vitro biomechanical testing of destabilized cadaveric human occipitocervical spine specimens. METHODS: Six human cadaveric specimens from the occiput to C3 were studied. Angular and linear displacement data were recorded while nonconstraining nondestructive loads were applied. Three methods of fixation were tested: contoured rod incorporating C1 with and without transarticular screws and contoured rod with transarticular screws without incorporating C1. RESULTS: All three constructs reduced motion to well within normal range. In contoured rod constructs with C1 wired, addition of transarticular screws slightly but significantly improved stability. In constructs with transarticular screws, incorporation of C1 into the contoured rod wiring did not improve stability significantly. CONCLUSIONS: Adding C1-C2 transarticular screws to a wired contoured rod construct where C1 is included only slightly improves stability. As the absolute reduction in motion from adding transarticular screws is small (<1 degree), it is doubtful whether any enhanced fusion from this additional procedure outweighs the surgical risks. However, transarticular screws provide an effective alternate method to fixate C1 when the posterior arch of C1 is absent or has been fractured.     

寰枢椎椎弓根螺钉固定融合技术治疗寰枢椎不稳

目的 探讨应用寰枢椎椎弓根螺钉固定技术治疗寰枢椎不稳的疗效.方法 对2003年6月至2009年3月收治的21例寰枢椎不稳患者应用寰枢椎椎弓根螺钉技术治疗,男14例,女7例;年龄28～66岁,平均42.5岁.齿状突骨折10例,先天性游离齿状突4例,Jefferson骨折合并齿状突骨折3例,类风湿关节炎致寰枢椎不稳4例.所有患者均伴有寰枢椎半脱位或失稳.患者术前JOA评分4～14分,平均9.1分.结果 21例患者共置入寰枢椎螺钉84枚,无一例患者发生脊髓、神经根和椎动脉损伤.术中均未发生椎动脉和脊髓损伤,有5例出现静脉丛出血.所有患者均获随访,时间6～48个月,平均16个月.术后JOA评分11～17分,平均15.9分,平均改善率为85.1%.骨折的齿状突均完全愈合,植骨块全部融化,无内固定断裂和松动.结论 寰枢椎椎弓根螺钉固定技术是治疗寰枢椎失稳的有效方法,具有固定牢靠、短节段固定,操作相对安全方便、融合率高等优点.     

寰枢椎椎弓根螺钉固定融合技术治疗寰枢椎不稳

目的 探讨应用寰枢椎椎弓根螺钉固定技术治疗寰枢椎不稳的疗效.方法 对2003年6月至2009年3月收治的21例寰枢椎不稳患者应用寰枢椎椎弓根螺钉技术治疗,男14例,女7例;年龄28～66岁,平均42.5岁.齿状突骨折10例,先天性游离齿状突4例,Jefferson骨折合并齿状突骨折3例,类风湿关节炎致寰枢椎不稳4例.所有患者均伴有寰枢椎半脱位或失稳.患者术前JOA评分4～14分,平均9.1分.结果 21例患者共置入寰枢椎螺钉84枚,无一例患者发生脊髓、神经根和椎动脉损伤.术中均未发生椎动脉和脊髓损伤,有5例出现静脉丛出血.所有患者均获随访,时间6～48个月,平均16个月.术后JOA评分11～17分,平均15.9分,平均改善率为85.1%.骨折的齿状突均完全愈合,植骨块全部融化,无内固定断裂和松动.结论 寰枢椎椎弓根螺钉固定技术是治疗寰枢椎失稳的有效方法,具有固定牢靠、短节段固定,操作相对安全方便、融合率高等优点.     

寰枢椎椎弓根螺钉固定融合技术治疗寰枢椎不稳

目的 探讨应用寰枢椎椎弓根螺钉固定技术治疗寰枢椎不稳的疗效.方法 对2003年6月至2009年3月收治的21例寰枢椎不稳患者应用寰枢椎椎弓根螺钉技术治疗,男14例,女7例;年龄28～66岁,平均42.5岁.齿状突骨折10例,先天性游离齿状突4例,Jefferson骨折合并齿状突骨折3例,类风湿关节炎致寰枢椎不稳4例.所有患者均伴有寰枢椎半脱位或失稳.患者术前JOA评分4～14分,平均9.1分.结果 21例患者共置入寰枢椎螺钉84枚,无一例患者发生脊髓、神经根和椎动脉损伤.术中均未发生椎动脉和脊髓损伤,有5例出现静脉丛出血.所有患者均获随访,时间6～48个月,平均16个月.术后JOA评分11～17分,平均15.9分,平均改善率为85.1%.骨折的齿状突均完全愈合,植骨块全部融化,无内固定断裂和松动.结论 寰枢椎椎弓根螺钉固定技术是治疗寰枢椎失稳的有效方法,具有固定牢靠、短节段固定,操作相对安全方便、融合率高等优点.     

Virtual placement of posterior C1-C2 transarticular screw fixation

We wanted to evaluate how often safe and effective posterior C1-C2 transarticular screw placement is realizable when it is performed according to guidelines given in the literature. In 50 adult patients, computerized tomography scan data from C0 to C3 were transformed into a 3D spine model. Virtually, bilateral screws were placed from the medial third of the C2-C3 facet joint towards the rim of the C1 anterior arc parallel to midline. Three categories of virtual screw position were rated: optimal (virtual screw inside the C2 pars interarticularis, transversing the middle third of the atlantoaxial joint, and sparing the vertebral artery canal), suboptimal (virtual screw violating the C2 pars interarticularis, and/or transversing the lower or upper third of the C1-C2 joint, and sparing vertebral artery canal), and unacceptable (virtual screw breaching the vertebral artery canal). Optimal placement was seen in 74, suboptimal placement in 11, and unacceptable locations in 15 sites. We conclude that due to the variability of the anatomy of the upper cervical spine, optimal transarticular C1-C2 screw placement is not possible in up to 26%, and even hazardous in up to 15%. This paper was presented in part at the Jahrestagung der Deutschen Gesellschaft für Neurochirurgie, May 25–28, 2003, Saarbrücken, Germany     

C1-C2 intra-articular screw fixation for atlantoaxial posterior stabilization

STUDY DESIGN: A trial of a new posterior stabilization technique for atlantoaxial instability and a report of preliminary results. OBJECTIVES: To describe a new posterior stabilization technique for atlantoxial instability. SUMMARY OF BACKGROUND DATA: Magerl's transarticular screw fixation is an accepted technique for rigid atlantoaxial stabilization, which reportedly has yielded many good clinical results. However, the technique is technically demanding and poses a risk of injury to the nerves and veins. METHODS: Eleven patients who had been treated with intra-articular screw fixation in combination with Halifax interlaminar clamp (OSTEONICS, Allendale, NJ) for atlantoaxial instability were observed. Results of their clinical examinations and biomechanical studies using resinous bones of a cervical spine model were reviewed. RESULTS: In all patients, occipital pain, neck pain, and neural deficit improved, and bony fusion with no correction loss was shown on radiography. To date, no vascular or neural complications have been found, and no instrumentation failures have occurred. In the biomechanical study, the Halifax with transarticular screw fixation had significantly greater flexion stiffness than the Halifax only or the Halifax with intra-articular screw fixation, but the torsion stiffness of the Halifax with intra-articular screw fixation was significantly greater than that of the other Halifax combinations. CONCLUSION: The preliminary results showed that this technique was effective in strengthening the rotational stability of the atlantoaxial fixation and was considered useful for atlantoaxial posterior stabilization.     

后路经侧块关节螺钉内固定技术治疗寰枢椎不稳

目的：评价Magerl法内固定治疗寰枢椎不稳或脱位的临床疗效。方法：寰枢椎不稳14例,男10例,女4例;年龄17～62岁,平均38.6岁。均实施后路复位,Magerl法经关节螺钉内固定和自体髂骨植骨。结果：14例患者共植入经关节螺钉28枚。所有患者获随访,时间9～35个月,平均16个月,术后JOA评分13.8～15.8分,平均（14.50±0.66）分。改善率平均（76.12±4.94）%。术后无椎动脉和脊髓损伤发生,植骨全部融合。结论：Magerl法固定是治疗寰枢椎不稳的良好方法之一,无须加用结构性植骨和辅助内固定,自体颗粒状松质骨植骨即可实现有效的骨性融合。     

颈1～2关节突间隙螺钉治疗颈2椎弓骨折

目的探讨应用颈1～2关节突间隙螺钉固定技术治疗颈2双侧椎弓骨折(Hangman骨折)的可行性及临床疗效.方法自2000年9月～2002年9月应用颈后路经颈1～2关节突间隙螺钉固定加植骨融合术治疗Hangman骨折6例,观察术后寰枢椎的稳定性、植骨融合率及颈椎活动度.结果 6例病人术中无神经及血管损伤等并发症,术后上颈椎即刻获得稳定,经6～26个月随访,全部病人均获得骨性愈合,螺钉无松动、退出及断裂,颈椎旋转活动度平均丧失35.72%.结论颈1～2关节突间隙螺钉固定技术治疗Hangman骨折是安全有效的,为重建寰枢椎间的稳定性提供了一种新的内固定方法.