Transoral decompression, anterior plate fixation, and posterior wire fusion for irreducible atlantoaxial kyphosis in rheumatoid arthritis

STUDY DESIGN: Fifteen consecutive patients with irreducible atlantoaxial kyphosis caused by rheumatoid arthritis were treated by combined transoral odontoid resection, anterior plate fixation, and posterior wire fusion. OBJECTIVES: To investigate the clinical results of this new surgical procedure. SUMMARY AND BACKGROUND DATA: Irreducible atlantoaxial kyphosis in rheumatoid arthritis results from a destruction of the craniocervical joint ligaments and the anterior aspects of the lateral atlantoaxial joints. The development of a paradental synovial pannus and atlantoaxial joint impaction prevents reduction by conservative treatment, such as skull traction. Posterior surgical procedures for the treatment of the irreducible atlantoaxial kyphosis with spinal cord compression have been associated with high morbidity and mortality. METHODS: Fifteen consecutive patients were treated by transoral odontoid resection. The fixation was performed with anterior plating, according to the method of Harms in combination with posterior wire fusion according to Brooks. Before and after surgery, evaluation was performed using the parameters of pain (visual analog scale), range of motion, and subjective assessment of improvement and the Health Assessment Questionnaire. The neurologic deficit was defined according to the classifications proposed by Ranawat, Frankel, and Nurwick. Plain radiographs, including lateral flexion and extension views, and magnetic resonance scans were obtained. RESULTS: No perioperative fatality occurred. The average clinical and radiographic follow-up was 50.7 +/- 15.6 months (range, 26-77). Postoperative pain was relieved (mean pain score before surgery, 7.9 +/- 1.87; after surgery, 3.8 +/- 1.27), and the range of motion of all patients increased (mean 21.5 +/- 14.0 degrees for rotation; mean 17.2 +/- 5. 54 degrees for bending). The score on the Health Assessment Questionnaire increased in three patients, remained unchanged in three and decreased in six patients (three had died). All patients improved at least one Ranawat level after surgery, except a patient in Ranawat Class II, whose condition remained unchanged. All patients were satisfied with the procedure and reported subjective improvement. CONCLUSION: Transoral plate fixation combined with posterior wire fixation after transoral odontoid resectionis an effective, reliable, and safe procedure for the treatment of irreducible atlantoaxial kyphosis in rheumatoid arthritis.     

Odontoid fractures: A retrospective analysis of 53 cases

Background:

The management of odontoid fracture has evolved but controversy persists as to the best method for Type II odontoid fractures with or without atlantoaxial (AA) instability. The anterior odontoid screw fixation can be associated with significant morbidity while delayed odontoid screw fixation has shown to be associated with reasonable good fusion rates. We conducted a retrospective analysis to evaluate the outcome of a trial of conservative management in type II odontoid fractures without atlantoaxial instability (Group A) followed by delayed odontoid screw fixation in cases in which fusion was not achieved by conservative treatment. The outcome of type II odontoid fracture with AA subluxation (Group B) was also analysed where closed reduction on traction could be achieved and in those atlantoaxial subluxations that were irreducible an intraoperative reduction was done.

Materials and Methods:

A retrospective evaluation of 53 cases of odontoid fractures treated over a 9-year period is being reported. All odontoid fractures without AA instability (n=29) were initially managed conservatively. Three patients who did not achieve union with conservative management were treated with delayed anterior screw fixation. Twenty-four cases of odontoid fractures were associated with AA instability; 17 of them could be reduced with skeletal traction and were managed with posterior fusion and fixation. Of the seven cases that were irreducible, the initial three cases were treated by odontoid excision followed by posterior fusion and fixation; however, in the later four cases, intra operative reduction was achieved by a manipulation procedure, and posterior fusion and fixation was performed.

Results:

Twenty-six of 29 cases of odontoid fracture without AA instability achieved fracture union with conservative management whereas the remaining three patients achieved union following delayed anterior odontoid screw fixation. 17 out of 24 odontoid fracture with atlantoaxial dislocation could be reduced on traction and these patients underwent posterior fusion and fixation. Optimal or near optimal reduction was achieved by on table manipulation in four cases which were irreducible with skeletal traction. Atlantoaxial stability was achieved in all cases. All cases were noted to be stable on evaluation with x-rays at six months.

Conclusions:

The initial conservative management and use of odontoid screw fixation only in cases where conservative management for 6–12 weeks has failed to provide fracture union have shown good outcome in type II odontoid fracture without AA instability rates. Intraoperative manipulation and reduction in patients where AA subluxation failed to reduce on skeletal traction followed by posterior fusion obviates the need for transoral odontoid excision.     

经皮显微脊柱内窥镜下松解复位植骨内固定治疗难复性寰枢关节脱位

目的探讨经皮显微脊柱内窥镜（MED）下松解、复位和寰枢椎（C1、2）侧块螺钉内固定植骨融合治疗难复性C1、2关节脱位的可行性和安全性。方法8例患者中齿突发育不良3例,陈旧性齿突骨折2例,先天性齿突缺如、颅底凹陷症和齿突不连各1例。按Symon和Lavender临床标准评定中型4例,重型3例,特重型1例,施行经皮MED下C1前间隙松解、复位、侧块螺钉固定和植骨融合术。结果8例难复性寰枢椎关节脱位7例完全复位,1例部分复位。全部采用经皮前路C1、2侧块螺钉固定,位置良好,平均手术时间120min（90-150min）,出血量150ml（100-250m1）。随访8-16个月,总有效率100％,显效率51．25％;椎管减压平均改善率76．5％。无内固定断裂与松脱,骨性愈合,颈部旋转受限30°～40°。结论MED下C1、2前间隙松解、复位、侧块螺钉固定和植骨融合治疗寰枢椎关节脱位,达到传统开放手术要求,此技术安全有效。     

Biomechanical assessment of transoral plate fixation for atlantoaxial instability

STUDY DESIGN: In an experimental study using human cadaver specimens the biomechanical data of anterior atlantoaxial plating according to Harms were evaluated. OBJECTIVES: The purpose of this study was to evaluate this method biomechanically. SUMMARY AND BACKGROUND DATA: The optimum fixation method to achieve fusion at the atlantoaxial joint after odontoid resection is still a matter of discussion. Isolated posterior surgical procedures for treatment of irreducible atlantoaxial kyphosis with spinal cord compression are associated with high rates of morbidity and mortality. Transoral atlantoaxial plate fixation has been designed by Harms as a fixation technique after odontoid resection. In a modification, this procedure has been combined with the posterior wire fusion according to Brooks. METHOD: Eight human cadaver craniocervical specimens were tested in flexion, extension, rotation, and bending with a nondestructive flexibility method using a nonconstrained testing apparatus. Five different groups were examined: 1) control group (intact); 2) unstable group (after dissection of the atlantoaxial ligaments and odontoidectomy), 3) Harms group (transoral atlantoaxial plate fixation) 4) Harms-Brooks group (transoral atlantoaxial plate fixation and dorsal atlantoaxial wire fixation); and 5) Magerl group (transarticular atlantoaxial screw fixation). In a second experimental series, failure loads of the Harms-Brooks and the Magerl fixation methods were determined. RESULTS: The angular displacement of the Harms-Brooks group and the Magerl group was less than in any other group. Stiffness values at 0-3.0 Nm loads in any direction were larger for the Harms-Brooks-and Magerl-fixated specimens than for the Harms, control, or unstable specimens. No statistically significant difference was observed between Harms-Brooks and Magerl reconstruction stiffness. Ultimate failure load in the Harms-Brooks group was higher than in the Magerl group. CONCLUSIONS: Experimentally, isolated anterior atlantoaxial plating was less stable than the combined reconstruction procedures. Transoral plate fixation according to Harms in combination with posterior wire fixation according to Brooks provided a failure load and stiffness equal to transarticular screw fixation according to Magerl.     

Upper cervical involvement in rheumatoid arthritis

Atlanto-axial dislocation and upward migration of the odontoid were studied in patients with rheumatoid arthritis treated conservatively and those treated by atlanto-axial posterior fusion. Upward migration of the odontoid was evaluated by Ranawat's and Redlund-Johnell's methods after determining the normal range in healthy Japanese adults. Of the 100 patients treated conservatively, atlanto-axial dislocation was found in 49% and upward migration of the odontoid in 26% by the former method, and in 8% by the latter method. The detection rate of these lesions increased with the increase in the duration of the disease and progression of rheumatoid lesions. Abnormal Ranawat values are associated with lesions in the C1-C2 segment and abnormal Redlund-Johnell values with 0-C2 lesions. The latter suggests severe conditions and seems to be a useful indicator for the diagnosis of upward migration of the odontoid in our study. Though rheumatoid lesions in the upper cervical spine mainly involved the C1-C2 level, marked deterioration of the atlanto-occipital joints was also occasionally observed. Therefore, in surgical treatment, attention should be paid also to this region. Patients with abnormal Redlund-Johnell values require spinal fixation including the occipital bone.     

Surgical treatment of atlanto-axial dislocation. An introduction of two new methods

In the past fourty-two months we have operatively treated twenty cases of several types of atlanto-axial dislocation (AAD) including an atlanto-axial deformity. A transoral retropharyngeal approach to the anterior arch of the atlas and the body of the axis was performed in two cases of AAD with dens fracture, 2 traumatic pure anterior AAD with relatively narrow spinal canal and 1 os odontoideum. The operative method we have devised is a modification of the transoral micro-surgical odontoid resection. In hyperextended position the fractured dens or os odontoideum comes to the position nearest to the anterior arch of the atlas and a distance between the atlas and the axis almost disappears. In this position a Halo device is installed and the anterior arch of the atlas, the dens and the body of the axis are fixed by an autograft all together. The articular joints between the atlas and the axis are also fixed by small grafts. The "three points fixation" of the atlanto-axial vertebrae may be a better and safer operative technique for selected AADs. Another method for AAD is a posterior atlanto-axial fixation using a metal plate (Urlich Medical Instruments Co., West Germany). This technique is a modification of fixation with wire and methyl methacrylate. A strong point of this new method is that the laminae of the atlas, axis and C3 vertebra in some cases, are fixed not with wire but a plate. The wire is used only to fix the plate on the laminae, so that the wire is not snapped on elastic fatigue.(ABSTRACT TRUNCATED AT 250 WORDS)     

Primary posterior fusion C1/2 in odontoid fractures: indications, technique, and results of transarticular screw fixation.

Odontoid fractures, especially unstable type II fractures have a poor prognosis in respect to healing. Therefore, operative stabilization (posterior fusion C1/2 or anterior screw fixation) has been suggested for the treatment of unstable type II and for some unstable type III fractures. Compared to posterior fusion C1/2, anterior screw fixation has proven to be effective; it has the advantage of leaving the motion segment C1/2 intact, therefore preserving at least some C1/2 rotation. However, in some instances, this method of stabilization is not indicated. In these cases, posterior fusion C1/2 is the treatment of choice. Primary posterior fusion C1/2 is indicated in (a) odontoid fracture associated with comminution of one or both atlanto-axial joints; (b) fracture of the odontoid associated with an unstable Jefferson fracture; (c) unstable type III odontoid fracture, when immobilization in a halo jacket or plaster cast is not suitable, as in elderly people or polytraumatized patients; (d) atypical type II fractures (comminuted or with oblique fracture in the frontal plane); (e) irreducible fracture dislocation C1/2, e.g., several-weeks-old fracture; (f) unstable type II or shallow and unstable type III odontoid fracture, when marked thoracic kyphosis is associated with limited extension of the cervical spine; (g) unstable type II or shallow type III odontoid fracture in elderly people with degenerative narrow spinal canal; (h) pathologic fracture of the odontoid. In all these instances, posterior fusion C1/2 is the treatment of choice. We prefer the transarticular screw fixation technique. Compared to other posterior fusion techniques, it has the advantage of increased stability and allows effective stabilization of C1/2 in a reduced position as well as immediate ambulation with minimal head support. This technique can also be performed when the posterior arch of the atlas is fractured or absent. Our experience of 12 acute odontoid fractures, managed by this technique, is presented. At follow-up, all C1/2 fusions were united in reduced position.     

前弓切除联合后路固定治疗齿突骨折畸形愈合

 目的探讨经口前路寰椎前弓切除、寰枢椎侧块关节松解联合后路复位内固定融合术治疗齿突骨折畸形愈合伴难复性寰枢椎脱位的疗效。方法2007年2月至2012年2月共收治6例齿突骨折畸形愈合伴难复性寰枢椎脱位患者,均有外伤史,均存在脊髓损伤表现。男5例,女1例;年龄36~57岁,平均45.5岁。术前日本骨科协会（Japanese Orthopaedic Association,JOA）评分为4~10分,平均（7.5±2.2）分;脊髓有效空间（space available for cord,SAC）为5~11 mm,平均（8.1±2.5） mm。采用经口前路寰椎前弓切除、寰枢椎侧块关节松解联合后路枕颈复位固定融合术,术后颈托外固定3个月。术后观察神经功能改善情况,行X线、CT检查观察寰枢椎复位及融合情况。结果6例患者均获得随访,随访时间12~20个月,平均16个月。寰枢椎术中得到较好复位,术后3个月获得骨性融合,随访期间内固定无松动。6例患者神经功能末次随访时JOA评分为10~15分,平均（14.7±2.1）分,较术前明显提高（差异有统计学意义）,神经功能改善率75.5%。末次随访时SAC为11~17 mm,平均（13.5±2.6） mm,较术前明显增大,差异有统计学意义。1例术后第5天出现后路切口渗液,督促患者采取侧卧位,避免切口受压,3周后切口愈合。1例术后第3天出现神智淡漠,化验室检查显示低钠、低钾血症,经及时补液,1 d后神智恢复正常。结论经口前路寰椎前弓切除、寰枢关节松解联合后路复位固定融合术是治疗齿突骨折畸形愈合伴难复性寰枢椎脱位的安全、有效方法,临床效果满意。     

齿状突骨折诊断及治疗方法的选择：（附30例临床报告）

本文报告３０例齿状突骨折的治疗情况。非手术治疗１６例，手术治疗１４例。着重对齿状突骨折的早期诊断和治疗的选择进行讨论。非手术治疗对于大多数新鲜齿状突骨折是有益的；对不稳定骨折或牵引复位失败的病例宜早期手术寰枢椎融合；对陈旧性骨折脱位伴有脊髓压迫症状，行寰椎后弓切除减压枕颈融合是一种有效的方法。     

后路钛缆与钢丝内固定治疗少儿寰枢椎不稳的临床对照试验

目的:探讨后路钛缆与钢丝治疗少儿寰枢椎不稳的疗效。方法:63例15岁以下寰枢椎不稳患者,男38例,女25例。分别行后路钛缆固定(32例),钢丝内固定(31例),均采用颗粒状自体松质骨植骨的寰枢椎后路融合术治疗。术后对两组手术时间、出血量、骨性融合时间、术后骨性融合病例数疗效进行比较。结果:手术时间:钢丝固定组(110±35.6)min,钛缆固定组(70±25.4)min,两组差异有统计学意义(t=6.205 4,P<0.05)。手术出血量:钢丝固定组(160±55.8)ml,钛缆固定组(120±35.3)ml,两组差异有统计学意义(t=6.235 7,P<0.05)。63例患者均获随访,随访时间3.2~12.9个月,平均6.1个月。术后骨性融合时间:钢丝固定组(3.8±0.3)个月,钛缆固定组(3.1±0.2)个月,两组差异无统计学意义(t=2.314 4,P>0.05)。钢丝固定患者中钢丝断裂4例,钢丝松脱2例,25例获骨性融合;钛缆固定患者中钛缆松脱1例,31例获骨性融合,未发生钛缆断裂、脊髓损伤等其他并发症。术后骨性融合病例数两组差异有统计学意义(2χ=4.199 4,P<0.05)。按疗效评定标准,钛缆固定组,优21例,良10例,可1例,差0例;钢丝固定组,优14例,良11例,可4例,差2例,两组差异有统计学意义(u=5.134 2,P<0.05)。结论:钛缆内固定具有手术时间短、术中出血少、并发症少等优点,是后路治疗少儿寰枢椎不稳的一种更为理想的方法。     

寰枢椎椎弓根钉板固定融合治疗上颈椎伤病临床体会

[目的]探讨经寰枢椎椎弓根钉板固定融合治疗上颈椎伤病的临床疗效。[方法]回顾2000年3月~2007年9月,徒手对50例上颈椎伤病患者进行后路经寰枢椎椎弓根钉板系统复位内固定,置入200枚寰枢椎椎弓根钉,在寰椎后弓及枢椎椎板间植骨融合,使寰枢椎复合体得到稳定。其中男36例,女14例;年龄20~65岁,平均41.52岁。Ⅱ型齿状突陈旧性骨折23例,齿状突不连12例,横韧带损伤15例。[结果]4例术后出现枕大神经痛,经对症治疗1个月后痊愈;2例螺钉穿破寰椎左侧椎弓根外侧壁,未发现脊髓、椎动脉损伤。48例获得随访,随访时间25~60个月,平均27.56个月,均获得骨性融合,未发现钉板断裂。所有患者X线片示寰椎完全复位,枢椎齿状突骨折处复位良好。CT片示螺钉与椎动脉及脊髓位置关系良好。按JOA评分标准,优34例,良13例,可2例,差1例;优良率94.00%。[结论]寰枢椎椎弓根螺钉结合钉板系统固定治疗上颈椎伤病,能显著增强寰枢椎间生物力学稳定性,植骨融合率高,该术式在寰枢椎融合术中具有较高的推广应用价值。     

Atlantoaxial synovial cyst. A case report

The case of a 62-year-old patient with an atlanto-axial synovial cyst is presented. The narrowing of the spinal canal was associated with anterior medullar compression and neurological deficit. A transoral approach with odontoid resection was performed. The diagnostic of synovial cyst was histologically confirmed. Secondary atlanto-axial instability required posterior fixation completed by C1-C2 transarticular screw fixation. The follow-up showed an improvement of the neurological deficit. Similar cases reported in the literature are reviewed and discussed.     

Transoral approach for the treatment of atlanto-axial dislocation with the Os odontoideum and obstruction of the bilateral vertebral arteries (author's transl)]

The two approaches are well-known in the surgical treatment of atlanto-axial dislocation, the one is the anterior and the other is the posterior approach. The indication of these methods is still controversial. This report concerns with one case of atlanto-axial dislocation with the separate odontoid and bilateral obstruction of both vertebral arteries, which was successfully treated by transoral decompression and fusion between the bodies of the atlas and axis. The reasons why we chose this method were: (1) the spinal cord decompression was necessary because of the presence of compression of the cord by the separate odontoid process, (2) the spinal fusion had to be performed to stabilize the atlanto-axial articulation, (3) it was necessary to avoid the damage of collateral circulations to the brainstem through the deep cervical arteries demonstrated by bilat vertebral angiography. The posterior approach is highly susceptible to injure these collateral circulations.     

Chiari I malformation associated with atlanto-axial dislocation: focussing on the anterior cervico-medullary compression

Summary Background. Chiari I malformation with atlantoaxial dislocation may cause both posterior and anterior cervicomedullary compression. We studied the clinicoradiological features and surgical outcome in patients having Chiari I malformation with atlantoaxial dislocation. Method. Thirty-nine patients with Chiari I malformation with atlanto-axial dislocation underwent preoperative and follow-up neurological status assessment. In Chiari I malformation with reducible atlanto-axial dislocation (n = 11), a direct posterior stabilization was done. In Chiari I malformation with irreducible atlanto-axial dislocation (n = 28), a single stage transoral decompression with posterior stabilization and/or posterior decompression and duraplasty were done in 18 patients. In 10 patients, only posterior decompression and/or posterior stabilization was performed. Seven among the latter patients subsequently deteriorated and required transoral decompression. Comparison of mean neurological status scores of patients with Chiari I malformation with irreducible atlanto-axial dislocation who underwent single stage transoral decompression with posterior stabilization versus the posterior procedure alone was done using T-test and proportional significance also calculated. Findings. Patients with Chiari I malformation with atlanto-axial dislocation have a high incidence of long tract signs and sphincteric disturbances with a decrease in the mean foramen magnum diameter. The mean neurological status scores of patients with Chiari I malformation with irreducible atlanto-axial dislocation who underwent single stage transoral decompression with posterior stabilization were significantly better than those patients who underwent the posterior procedure alone. The latter patients also showed significant clinical improvement following transoral decompression. In the presence of Chiari I malformation with reducible atlanto-axial dislocation, reduction and stabilization of atlanto-axial dislocation resulted in neurological improvement. The follow up neurological status scores of these patients improved after surgical intervention even in the presence of poor preoperative grades. Conclusions. Patients with Chiari I malformation should be investigated for the presence of atlanto-axial dislocation. In case atlantoaxial dislocation coexists, priority must be given to relieving anterior cervicomedullary compression.     

Spine fusion for atlanto-axial instability.

A follow-up study was done on fifty-seven spine fusions for atlanto-axial instability, classified as Type I - deficient odontoid (twenty-eight patients), Type II - deficient ligaments (twenty-three patients), and Type III - rotatory fixation (six patients). The average age of the patients at the time of the fusion was thirty years, and half had had significant trauma. Symptoms had been present for an average of 12.3 months before fusion. Preoperatively pain was the predominant complaint in twenty-nine; neurological complaints, in twenty-four; and instability in the rest. Of the forty-six Gallie fusions, there was one non-union and of the eleven occipitocervical fusions, two non-unions. Follow-up averaging 4.2 years revealed resolution of symptoms in almost all patients.     

寰枢关节360°松解在经口寰枢椎复位钢板内固定术治疗僵硬难复性寰枢椎脱位中的应用

目的探讨在经口寰枢椎复位钢板(TARP)内固定术中采用寰枢关节360°松解技术治疗僵硬难复性寰枢椎脱位的临床疗效。方法 2005年1月—2014年12月,对23例常规方法不能彻底松解的僵硬难复性寰枢椎脱位患者采用寰枢关节360°松解TARP内固定术治疗。通过术前、术后影像学检查(X线、CT三维重建和MRI)判断寰枢椎复位、内固定器位置及脊髓受压改善情况。采用日本骨科学会(JOA)评分评估患者临床症状改善情况。结果所有患者手术均顺利完成,术后颈椎局部症状和肢体麻木无力均不同程度改善,术后影像学资料显示内固定位置满意,脊髓压迫均彻底解除。所有患者术后随访6~12个月(平均9.3个月),末次随访时JOA评分由术前(8.5±3.2)分提高至(13.2±2.1)分;所有患者均获骨性融合。除1例患者因术中硬膜破裂,二期拆除TARP改为后路枕颈固定,其他患者未发生感染、神经血管损伤、钉板松脱等并发症。结论按常规方法不能完成充分松解的由陈旧性骨痂和瘢痕等因素造成的僵硬难复性寰枢椎脱位,采用寰枢关节360°松解技术可以获得彻底松解,再行TARP内固定术即可完成寰枢关节的完全复位,彻底解除脊髓压迫。     

Transoral decompression and posterior fusion for rheumatoid atlanto-axial subluxation

Cervical myelopathy is an uncommon but potentially fatal complication of rheumatoid atlanto-axial subluxation. Computerised myelotomography with three-dimensional reconstruction shows that rheumatoid pannus, together with the odontoid peg, contributes significantly to anterior cervico-medullary compression. These findings were the basis for treatment by transoral anterior decompression and posterior occipitocervical fusion, which removes both bony and soft-tissue causes of compression and allows early mobilisation without major external fixation. We report encouraging results from this combined approach in 14 patients who had progressive neurological deterioration.     

Biomechanical investigation of a novel integrated device for intra-articular stabilization of the C1-C2 (atlantoaxial) joint

Background contextThe anatomy of the atlantoaxial joint makes stabilization at this level challenging. Current techniques that use transarticular screw fixation (Magerl) or segmental screw fixation (Harms) give dramatically improved stability but risk damage to the vertebral artery. A novel integrated device was designed and developed to obtain intra-articular stabilization via primary interference fixation within the C1–C2 lateral mass articulation.PurposeTo assess the atlantoaxial stability achieved with a novel integrated device when compared with the intact, destabilized, and stabilized state using the Harms technique.Study designA biomechanical study of implants in human cadaveric cervical spines.MethodsSix human cadaveric specimens were used. Biomechanical testing was performed with moment control in flexion-extension, lateral bending, and axial rotation. Range of motion (ROM) was measured in the intact state, after both destabilization by creation of a Type II odontoid peg fracture and sequential stabilization using the integrated device and the Harms technique.ResultsMean flexion-extension ROM of the intact specimens at C1–C2 was 14.1°±2.9°. Destabilization increased the ROM to 31.6°±4.6°. Instrumentation with the Harms technique reduced flexion-extension motion to 4.0°±1.4° (p<.01). The integrated device reduced flexion-extension motion to 3.6°±1.8° (p<.01). In lateral bending, the respective mean angular motions were 1.8°±1.1°, 14.1°±5.8°, 1.4°±0.7°, and 0.4°±0.3° for the intact destabilized Harms technique and integrated device. For axial rotation, the respective mean values were 67.3°±13.8°, 74.2°±16.1°, 1.4°±0.7° and 0.9°±0.7°. Both the Harms technique and integrated device significantly reduced motion compared with the destabilized spine in flexion-extension, lateral bending, and axial rotation (p<.05). Direct comparison of the Harms technique and the integrated device revealed no significant difference (p>.10).ConclusionsThe integrated device resulted in interference fixation at the C1–C2 lateral mass joints with comparable stability to the Harms technique. Perceived advantages with the integrated device include avoidance of fixation below the C2 lateral mass where the vertebral artery is susceptible to injury, and access to the C1 screw entry point through the blade of the integrated device avoiding extended dissection superior to the C2 nerve root and its surrounding venous plexus.     

Transoral approach to extradural non-neoplastic lesions of the craniovertebral junction

Background

The transoral approach allows for an unobstructed anterior view of the craniovertebral junction from the lower clivus to C1 and C2. It can be applied to a heterogeneous spectrum of pathological lesions involving this area including craniovertebral junction malformations, atlanto-axial synovial cysts, pseudoarthrosis following odontoid fractures, selected cases of retro-odontoid pannus, and vertical translocation in rheumatoid patients.

Methods

Microsurgical strategy is dictated by the nature and site of the target lesion. Atlas preservation during transoral approach (atlas-sparing technique) minimizes postoperative instability and is suitable for the majority of extradural non-neoplastic lesions of the craniovertebral junction. The transoral trans-atlas approach allows for a wider exposure of the anterior craniovertebral junction, but at the price of a higher incidence of postoperative instability; it is usually required in patients with severe basilar invagination or irreducible vertical translocation in rheumatoid arthritis.

Conclusions

The transoral corridor is an effective route to approach a variety of anterior extradural lesions of the craniovertebral junction. Tailoring the approach to each specific lesion provides the needed exposure whilst limiting postoperative instability.     

齿状突合并周围骨折的诊断和治疗

目的：探讨齿状突合并周围骨折的诊治方法。方法：2003年1月～2006年3月我院收治新鲜齿状突骨折合并周围骨折17例。经急诊颈椎正侧位X线片、颅骨牵引后颈椎张口位及侧位X线片、CT冠状面和矢状面平扫加重建，诊断齿状突骨折合并周围骨折。采用谭明生法、Harms法和AO拉力螺钉对本组患者行寰枢椎椎弓根螺钉同定，用自体髂后上棘松质骨行寰枢椎后表面植骨融合．随访观察疗效。结果：17例齿状突骨折患者术前影像学诊断合并齿状突周围骨折20处，术中发现周围骨折5例5处．共25处骨折．平均每例患者1．5处周围骨折。所有患者手术顺利，可疑椎动脉挫伤1例。术后随访3个月～3年，平均1．4年，颈枕部疼痛1例：复查X线片显示齿状突骨折均愈合，畸形愈合3例，合并存在的25处齿状突周围骨折均愈合．无钉棒系统松动、断裂。结论：齿状突合并周围骨折是齿状突骨折的一种特殊类型，由于影像学的局限性．术前准确诊断很闲难。采用寰枢椎椎弓根螺钉短节段固定融合治疗效果满意．