Outcomes of C1 and C2 posterior screw fixation for upper cervical spine fusion

To achieve stable fixation of the upper cervical spine in posterior fusions, the occiput is often included. With the newer techniques, excluding fixation to the occiput will retain the occiput–cervical motion, while still allowing a stable fixation. Harms’s technique has been adapted at our institution and its effectiveness for indications such as C2 complex fractures and tumors using C1 or C2 as endpoints of a posterior fixation are reviewed. Fourteen cases were identified, consisting of one os odontoideum; four acute fractures and four non-unions of the odontoid; three tumors and two complex fractures of C2 vertebral body, and one C2–C3 post-traumatic instability. One misplaced screw without clinical consequences was the only complication recorded. Screw loosening or migration was not observed at follow-up, showing a stable fixation.     

Surgical treatment of an atlantoaxial fracture after a delayed diagnosis in a comatose patient

Study design

Case report.

Objective

To report a case of fractures of the right lateral atlantoaxial joint and C2 body diagnosed more than 5 months after injury.

Summary of background data

Misdiagnosis of an injury to the cervical spine has been reported frequently. For patients in whom cervical injury is suspected, the primary screening modality is axial CT from the occiput to T1 with sagittal and coronal reconstructions. The inadequacy of this radiological evaluation could delay diagnosis of fractures and lead to unnecessary surgical treatment of the cervical spine.

Methods

We report the case of a 74-year-old woman with an old, displaced combined fracture of the C1 and C2 right facet joint. In this case, CT of the brain was evaluated at the time of injury, but not CT of the cervical spine. As a consequence, diagnosis was delayed and surgical treatment was necessary.

Results

We performed posterior fusion surgery for C1 and C2. A pedicle screw was not inserted on both sides of C2, because of destruction of the insertional point on the right side and a high-riding VA on the left. Alternatively, a lamina screw and hook were used for C2, fixed with lateral mass screws on C1, with a bone graft harvested from the iliac crest.

Conclusions

To avoid unnecessary surgery, surgeons should recognize the possibility of cervical fractures that cannot be detected without CT, especially in patients who are comatose at injury. Atlantoaxial fixation with a hook and lamina screw in C2 is an option for old upper cervical fractures in cases where a pedicle screw cannot be inserted into C2.

     

A retrospective study of congenital osseous anomalies at the craniocervical junction treated by occipitocervical plate-rod systems

Purpose

To evaluate the effectiveness of posterior occipitocervical reconstruction using the anchors of cervical pedicle screws and plate-rod systems for patients with congenital osseous anomalies at the craniocervical junction.

Methods

Twenty patients with congenital osseous lesions who underwent posterior occipitocervical fusion using the anchors of cervical pedicle screws and plate-rod systems for reduction and fixation from 1996 to 2009 were reviewed. The lesions included os odontoideum, occipitalization of the atlas, congenital C2–3 fusion, congenital atlantoaxial subluxation, congenital basilar invagination and combined anomalies. The clinical assessment and the measurements of the images were performed preoperatively, postoperatively and at most recent follow-up.

Results

The combined deformity of flexion of the occipitoatlantoaxial complex and invagination of the odontoid process associated with congenital osseous lesions at the craniocervical junction was corrected by application of combined forces of extension and distraction between the occiput and the cervical pedicle screws. Preoperative myelopathy improved in 94.7 % patients. The mean Ranawat value, Redlund-Johnnell value, atlantodental distance, occiput (O)–C2 angle, and C2–C7 lordosis angle improved postoperatively and was sustained at most recent follow-up. The mean cervicomedullary angle improved from 129.3° preoperatively to 153.3° postoperatively. The mean range of motion at the lower adjacent motion segment remained unchanged at most recent follow-up. The fusion rate was 95 %.

Conclusions

The results of the present study indicate that posterior occipitocervical reconstruction using the anchors of cervical pedicle screws and plate-rod systems is an effective technique for treatment of deformities and/or instability caused by congenital osseous anomalies at the craniocervical junction.     

Posterior atlantoaxial subluxation due to os odontoideum combined with cervical spondylotic myelopathy : a case report

In patients with os odontoideum and posterior atlantoaxial subluxation are extremely rare. No reports have described posterior atlantoaxial subluxation associated with os odontoideum combined with cervical spondylotic canal stenosis, both of which require surgical treatment. We report one case of a 75-year-old female who underwent arthrodesis between the occiput and C3 using a hook-and-rod system and also a double-door laminoplasty from levels C3 to C7. The claw mechanism was applied between the C2 lamina and the C3 inferior articular process. The posterior atlantoaxial subluxation was completely reduced by the method that the rod gradually pushed the posterior arch of C1 anteriorly during connection to the occiput. Twelve months after surgery, the patient showed improvement in preoperative clumsiness and gait disturbance, and the latest plain radiographs showed solid osseous fusion, with no loss of correction or instrumentation failure.

     

Odontoid fractures: high complication rate associated with anterior screw fixation in the elderly

This study is a retrospective analysis of patients older than ¶65 years with odontoid fractures. The series consisted of 29 consecutive patients with odontoid fractures (18 women, mean age 78, range 66–99 years). Twenty-six patients were neurologically intact, Frankel E, whereas three had neurological symptoms: two Frankel D and one Frankel C. Eleven patients were treated with anterior screw fixation according to Böhler, seven with a posterior C1–C2 fusion. Ten patients with either minimally displaced ¶fractures or with complicating medical conditions were treated conservatively. At follow-up, 7/7 patients with posterior fusion had healed without any problems, whereas ¶8/11 patients treated with anterior screw fixation, and 7/10 conservatively treated patients were either failures or had healed, but after a complicated course of events. We conclude that anterior screw fixation according to Böhler is associated with an unacceptably high rate of problems in the elderly. Probable causes may be osteoporosis with comminution at the fracture site, or stiffness of the cervical spine preventing ideal positioning of the screws. As non-operative treatment also often fails, the method of choice seems to be posterior C1–C2 fusion.     

C3–C4 spondyloptosis without neurological deficit—a case report

Background contextTraumatic spondyloptosis of the cervical spine is usually associated with a complete, or rarely a partial, neurological deficit. Traumatic spondyloptosis with bipedicular fracture of the C3 vertebra is uncommon. To the best of the authors' knowledge, there is no report in the literature of bipedicular fracture of C3 with spondyloptosis of C3 over C4 with no neurological deficit. Literature is not clear about the role of preoperative traction in neurologically intact patients, and most authors advise both anterior and posterior fixation for cervical spondyloptosis.PurposeTo report a case of C3–C4 spondyloptosis with C1 and C2 posterior arch fractures with no neurological deficit and its management strategy and underline the fact that closed reduction and limited anterior fusion can preserve the motion segment of cervical spine at other fractured levels and give a stable cervical column with good long-term results.Study designA case report with review of the literature.MethodsA 35-year-old man fell from a height with hyperextension-compression injury to the cervical spine. The patient suffered fracture of the posterior elements of C1–C3 along with spondyloptosis of C3 over C4 without any neurological deficit. The patient was treated with an awake nasotracheal intubation with gradual cervical traction under fluoroscopic guidance to acceptable alignment followed by anterior cervical fusion at C3–C4.ResultsAt 24 months' follow-up, the C3–C4 level fused completely with fracture healing at C1 and C2. The patient remained asymptomatic with normal neurological examination and near complete cervical motion. The patient returned to his preinjury job and recreational activities.ConclusionsA case of C3–C4 spondyloptosis with associated C1–C2 posterior arch fracture is reported. The patient can present without neurological deficit if associated with a fracture of the posterior elements. Spondyloptosis without neurological deficit can be treated with gradual reduction under fluoroscopic guidance. A limited anterior-only fusion at the spondyloptosis level can provide good long-term results with preservation of other motion segments.     

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.     

Plate fixation for Letenneur type I Hoffa fracture: a biomechanical study

BackgroundA coronal fracture of the posterior femoral condyle, also known as a Hoffa fracture, is an unusual injury, and there are only a handful of case reports or series exploring it. The optimal fixation method of these intraarticular fractures remains controversial; improper or unstable fixation usually lead to an unsatisfactory prognosis. The use of posterior–anterior or reversed lag screw fixation is still a popular method. Additional buttress plating is also recommended for fixation of these difficult fractures. The purpose of this study was to compare the mechanical strength of four different fixation patterns for this uncommon fracture.Material and methodsSixteen sawbone simulated models of Letenneur type I Hoffa fractures were created with one of four fixation patterns: two screws implanted in the anterior–posterior (AP) direction or posterior–anterior (PA) direction; one screw in the PA direction with a plate implanted in the posterior position of the distal femoral condyle or with a plate in the lateral position. Biomechanical testing was performed to determine the post-fixation axial stiffness, the maximum load to failure and the fragment vertical displacement for each of the four constructs.ResultsThe plate fixation patterns whether implanted in the posterior or lateral position were shown to provide higher overall axial stiffness and load to failure, and less vertical displacement than the other two patterns of pure screw fixation. Among these constructs, the lateral plate fixation was found to provide the highest stiffness and load to failure and the least displacement for the posterior condylar fragments, followed by the posterior plate fixation. The lowest overall stiffness and load to failure and the largest vertical displacement were found in the construct with the AP direction placed screws.ConclusionIt was concluded that the lateral position implanted plate is biomechanically the strongest fixation method for Letenneur type I Hoffa fractures. However, this plate fixation is not recommended for all cases. The choice of internal fixation pattern depends on the surgeons.     

Mortality related to and functional outcomes of upper cervical spine fractures in the elderly

BackgroundAlthough the mortality related to hip fracture and osteoporotic vertebral fracture have been reported, few studies have examined the mortality related to atlas and/or axis fractures. The aim of this study was to assess the association between mortality and atlas and/or axis fractures retrospectively and to elucidate the efficacy of surgical treatment.MethodsA total of 33 elderly patients who were treated for atlas and/or axis fractures at our institution between January 2012 and December 2018 were included in this study. These patients were divided into two groups: surgical treatment and conservative treatment. Fracture types, comorbidities, neurological status, treatment types, and walking ability at follow-up were reviewed. Mortality was assessed using medical records or via phone interviews.ResultsThe mean age at injury was 79.9 ± 8.0 years, and the mean follow-up period was 2.3 years. The overall mortality rates at 1 and 5 years were 21.4% and 48.4%, respectively. During the observation period, 12 (36%) patients died. Twenty-two patients were treated conservatively (14 were treated with a cervical collar, 8 were treated with a halo vest). Surgical procedures included occipital-cervical fixation, osteosynthesis of C2 fractures, C1–2 fixation, and C1–4 fixation using a posterior approach. Surgical treatment correlated with better survival rates. There was no significant difference between the two groups in terms of ambulatory ability and functional recovery.ConclusionUpper cervical spine fractures appear to have a worse prognosis compared to hip and osteoporotic vertebral fractures. This study indicates the efficacy of surgical treatment for upper cervical spine fractures in the elderly for improving survival prognosis.     

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.     

Sagittal range of motion after extensive cervical fusion

Background contextComplicated cervical spine revision and deformity correction surgeries are becoming increasingly common. These challenging operations often necessitate fusion of the entire cervical spine. Patients frequently express concern over the likely loss of range of motion (ROM) of the neck postoperatively. However, we are aware of no study that specifically examines the sagittal cervical ROM after extensive cervical fusion.PurposeTo characterize sagittal ROM after extensive cervical fusion.Study designRetrospective case series.Patient sampleThirty patients were included.Outcome measuresRadiographs at final follow-up were measured for cervical ROM by the occipitocervical and cervicosternal angles with the neck in full flexion and extension.MethodsThe surgical and medical records at one tertiary referral academic institution were used to identify adults who had undergone extensive cervical fusion between 1996 and 2008. An “extensive cervical fusion” entailed an upper instrumented vertebra proximal to C3 and lower instrumented vertebra distal to C7. Radiographs at final follow-up were measured for cervical ROM by the occipitocervical and cervicosternal angles with the neck in full flexion and extension.ResultsThe average age at surgery was 58.3±10.0 years. The surgical levels were occiput–T1 (one patient), occiput–T4 (one patient), occiput–T6 (one patient), C1–T1 (one patient), C1–T2 (one patient), C2–T1 (nine patients), C2–T2 (eight patients), C2–T3 (six patients), and C2–T4 (two patients). Twenty-seven of the procedures were revisions. The other surgical indications were chin-on-chest deformity (one patient), cervical scoliosis (one patient), and multilevel cervical myelopathy (one patient). The mean follow-up period was 34.5±30.9 months (range, 6–154 months). The mean cervical ROM values by the occipitocervical and cervicosternal angles were 29.5±11.0° and 7.5±5.0°, respectively. The mean total cervical ROM value was 34.1±14.7°.ConclusionsA substantial degree of sagittal ROM can be maintained after extensive surgical fusion of the cervical spine.     

Biomechanical evaluation of occipitocervicothoracic fusion: impact of partial or sequential fixation

BACKGROUND CONTEXT: Surgical instrumentation used for posterior craniocervical instability has evolved from simple wiring techniques to sophisticated implant systems that incorporate multiple means of rigid fixation for the cervical spine. Polyaxial screws and lamina hooks in conjunction with occipital plating and transitional rods for caudal fixation theoretically allow for fixation points at each vertebra along the posterior aspect of the cervical spine. However, the potential for anatomical constraints to prevent intraoperative instrumentation at the desired vertebral level exists. The biomechanical implications of such "skipped segments" have not been well documented. PURPOSE: The purpose of this study was to determine the biomechanical effects of partial three-point fixation versus sequential fixation at all levels of the cervical spine from the occiput to T1. STUDY DESIGN/SETTING: Fresh frozen human cadaveric cervical spines from the occiput (CO) to T1 were prepared and mounted on a spine simulator. Motion was assessed by a three-dimensional optoelectronic motion measurement system. Kinematic data were collected and range of motion (ROM) was analyzed and reported. METHODS: Eight human noninstrumented intact spines (Treatment 1) were tested for baseline ROM which was subclassified into axial (CO-C2), upper subaxial (C2-C4), lower subaxial (C4-T1), and total (CO-T1) ROM. Flexion extension, lateral bending, and axial torsion testing with an applied +/-3Nm moment was conducted. The same testing protocol was performed after three-point fixation in which screws were placed at the CO, C4, and T1 (Treatment 2), and also after sequential fixation at all levels from CO through T1 (Treatment 3). Fixation was achieved using an occipital plate, 12-mm lateral mass screws for C3 through C6, and 20-mm lateral mass or pedicle screws were used for C1, C2, C7, and T1. RESULTS: Intact spine testing (Treatment 1) showed statistically significant larger ROM for all segments and for overall ROM when compared with both Treatment 2 (partial fixation CO, C4, and T1) and Treatment 3 (sequential fixation at all levels from the occiput to T1). When comparing Treatment 2 with Treatment 3, no significant difference in flexion extension ROM was detected between axial, upper subaxial, lower subaxial, and total overall ROM (p > .05). Lateral bending showed statistically significant increased ROM for Treatment 2 constructs compared with Treatment 3 constructs in total overall lateral bend ROM. For axial rotation, there was significantly increased ROM for Treatment 2 at the lower subaxial segment and total overall ROM (p < .05) when compared with Treatment 3. CONCLUSIONS: There was no statistical difference between the three-point fixation treatment group and the sequential fixation group in flexion extension bending. Lateral bending and axial rotation demonstrated an increase in total overall ROM with partial fixation compared with fixation at all levels. Axial rotation in particular showed increased mobility in the lower cervical spine for the partial fixation group. In the instance where surgeons are not able to apply sequential fixation at diseased levels, especially for the lower subaxial cervical spine, particular attention to limitation of lateral bending and axial rotation by the use of external orthotics must be considered.     

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.     

APS Recommendations for the Urological Evaluation of Patients with Spinal Cord Injury

Abstract

Context

The complex anatomy and the importance of ligaments in providing stability at the upper cervical spine region (O–C1–C2) require the use of many imaging modalities to evaluate upper cervical injuries (UCI). While separate classifications have been developed for distinct injuries, a more practical treatment algorithm can be derived from the injury pattern in UCI.

Objective

To propose a practical treatment algorithm to guide treatment based on injuries characteristic of UCI.

Methods

A literature review was performed on the Pubmed database using the following keywords: (1) “occipital condyle injury”; (2) “craniocervical dislocation or atlanto-occipital dislocation or craniocervical dislocation”; (3) “atlas fractures”; and (4) “axis fractures”. Just articles containing the diagnosis, classification, and treatment of specific UCI were included. The data obtained were analyzed by the authors, dividing the UCI into two groups: Group 1 – patients with clear ligamentous injury and Group 2 – patients with fractures without ligament disruption.

Results

Injuries with ligamentous disruption, suggesting surgical treatment, include: atlanto-occipital dislocation, mid-substance transverse ligament injury, and C1–2 and C2–3 ligamentous injuries. In contrast, condyle, atlas, and axis fractures without significant displacement/misalignment can be initially treated using external orthoses. Odontoid fractures with risk factors for non-union are an exception in Group 2 once they are better treated surgically. Patients with neurological deficits may have more unstable injuries.

Conclusions

Ascertaining the status of relevant ligamentous structures, fracture patterns and alignment are important in determining surgical compared with non-surgical treatment for patients with UCI.     

Stability analysis of craniovertebral junction fixation techniques

BACKGROUND: Craniovertebral arthrodesis in the upper cervical spine is challenging because of the high degree of mobility afforded by this region. A novel method for achieving atlantoaxial fixation with use of polyaxial screws inserted bilaterally into the lateral masses of C1 and transpedicularly into C2 with longitudinal rod connection has recently been introduced. The question remains as to whether this technique provides adequate stability when extended cephalad to include the occiput. The purpose of this study was to determine the primary stability afforded by this novel construct and compare its stability with the current standard of bilateral longitudinal plates combined with C1-C2 transarticular screws. METHODS: We used ten fresh-frozen human cadaveric cervical spines (C0-C4). Pure moment loads were applied to the occiput, and C4 was constrained during the testing protocol. We evaluated four conditions: (1) intact, (2) destabilized by means of complete odontoidectomy, (3) stabilization with longitudinal plates with C1-C2 transarticular screw fixation, and (4) stabilization with a posterior rod system with C1 lateral mass screws and C2 pedicle screws. Rigid-body three-dimensional rotations were detected by stereophotogrammetry by means of a three-camera system with use of marker triads. The range of motion data (C0-C2) for each fixation scenario was calculated, and a statistical analysis was performed. RESULTS: Destabilization of the specimen significantly increased C0-C2 motion in both flexion-extension and lateral bending (p < 0.05). Both fixation constructs significantly reduced motion in the destabilized spine by over 90% for all motions tested (p < 0.05). No significant differences were detected between the two constructs in any of the three rotational planes. CONCLUSIONS: Both hardware systems provide equivalent construct stability in the immediate postoperative period when it is critical for the eventual success of a craniovertebral arthrodesis. On the basis of this work, we believe that the decision to use either construct should be determined by clinical rather than biomechanical concerns.     

Clinical and radiologic outcome of laminar screw at C2 and C7 for posterior instrumentation—review of 25 cases and comparison of C2 and C7 intralaminar screw fixation

BackgroundThe aim of this study is 2-fold: to analyze a clinical case series in which we used laminar screws for cervical posterior instrumentation and to describe the difference between C2 and C7 laminar screws in terms of technique and anatomy.MethodsData were obtained from 25 patients who underwent cervical posterior fixation with intralaminar screws at C2 or C7. C2 intralaminar screw instrumentation was used for 7 patients requiring occipitocervical fixation (basilar invagination [3 patients], C1 unstable bursting fracture [1 patient], C1-C2 instability with occipital assimilation [2 patients], and dystopic os odontoideum [1 patient]), 13 patients with C1-C2 instability, 1 patient with C2-C3 subluxation, and 4 patients undergoing C7 fixation due to pseudoarthrosis or cervical instability after trauma. A total of 34 laminar screws were placed including 1 thoracic laminar screw, and the patients were assessed both clinically and radiographically.ResultsThere were no instances where a screw violated the spinal canal nor any hardware fractures noted during the follow-up period. As for perioperative complications, there were 2 cases of postoperative wound infection, 1 case of dural laceration during dissection, and 2 cases of partial dorsal laminar breach. However, there was no neurologic compromise in any of the cases. The fusion success rate was 100%.ConclusionThese preliminary results support the use of intralaminar screws for posterior instrumentation at C2 and C7.     

The Lateral Transfacetal Retrovascular Approach for an Anteriorly Located Chordoma Originating from the Second Cervical Vertebra

Summary  Background. Anteriorly located lesions at the craniocervical junction (CCJ) require careful surgical planning to avoid neuraxis retraction. Several different routes have been described in the search for the most appropriate yet least invasive approach. However, most of these far-lateral posterior approaches are specifically tailored for non-osseous intradural tumours or chordomas with cephalad extension. We introduce an approach that allows for better access to laterally extending osseous tumours originating from the second cervical vertebra. Using this approach, the lesion is manipulated from a strictly lateral direction parallel to a plane through the articular pillar of the CCJ and the odontoid process, and the C1- and C2-laminae are spared for posterior fixation.  Method. The application of this approach is demonstrated in detail by an illustrative case of a chordoma originating from C2 that presented with intradural mass effect, considerable bone destruction, far-lateral extension to the right, and vertebral artery involvement.  Findings. The described approach gave ample access for total tumour resection. It allowed for safe control and displacement of the vertebral artery, spinal cord decompression, C2-corpectomy across the midline, and anterolateral bone reconstruction. No C1- or C2-hemilaminectomy was needed, and these bone elements could be used for posterior fixation (the patient presented in this study was referred to our institution after posterior fixation from the occiput to C3 had already been performed elsewhere). No intra-operative or postoperative complications occurred. At the 6-month follow-up, the patient was fully ambulatory with no neurological deficit.  Interpretation. The described lateral transfacetal route is the method of choice for operating on laterally extending osseous tumours originating from the second cervical vertebra.     

Lateral mass screw–rod fixation of the cervical spine: a prospective clinical series with 1-year follow-up

BACKGROUND CONTEXT: Lateral mass plating has become the technique of choice for posterior cervical fixation. Although these systems are safe and reliable, they can be difficult to use in patients with abnormal cervical anatomy; screw placement can be compromised by the fixed hole spacing of the plate; screw back-out and other forms of implant failure can occur; and extension across the cervicothoracic junction can be problematic. PURPOSE: To report a series of patients undergoing posterior cervical stabilization with a polyaxial screw-rod construct and to investigate whether this new system offers any advantages over existing methods of fixation. STUDY DESIGN: A prospective study evaluating clinical and radiographic parameters in a consecutive series of patients treated with this technique. PATIENT SAMPLE: There were 21 patients in the study group. The surgical indication was cervical spondylosis in 14, trauma in 2, postsurgical kyphosis in 2 and 1 case each of congenital cervicothoracic stenosis, C7-T1 pseudarthrosis and basilar invagination with brainstem compression. OUTCOME MEASURES: Clinical indicators included age, gender, neurologic status, surgical indication and number of levels stabilized. Note was made of whether laminectomy and concomitant anterior reconstructive surgery were performed. Radiographic indicators included early postoperative computed tomography (CT) scan to check for screw placement and plain radiographs at subsequent visits. METHODS: The participants in this study underwent posterior cervical stabilization using lateral mass screw-rod fixation. Clinical and radiographic assessment was carried out immediately after surgery, and 3, 6 and 12 months after surgery. One-year follow-up was obtained in all cases. RESULTS: A total of 212 screws were implanted in 21 patients. Fixation was carried out over an average of 5.5 spinal segments (range, 2 to 11). The system was successfully implanted in all patients despite the presence of coronal and sagittal plane deformities and/or lateral mass abnormalities in the majority of cases. This system allowed for screw placement in the occiput, C1 lateral mass, C2 pars, C3-C7 lateral masses and upper thoracic pedicles. Early postoperative CT scanning confirmed satisfactory screw placement in all cases. Three patients experienced transient single-level radiculopathy, for an incidence of 1.4% per screw placed. Two patients developed wound seromas requiring evacuation. There were no infections or other wound healing problems. There were no examples of cord or vertebral artery injury, cerebrospinal fluid leak, screw malposition or back-out, loss of alignment or implant failure. When compared with plating techniques, screw-rod fixation appeared to offer several advantages. First, unlike plates, rods proved to be amenable to multiplanar contouring, which is often needed for deformities associated with cervical spondylosis. Second, lateral mass screw placement was more precise because it was not constrained by the hole spacing of the plate. Third, screw back-out and other types of implant failure were not seen. Fourth, the screw-rod system was more easily extended to the occiput and across the cervicothoracic junction. Fifth, the screw-rod system permitted the application of compression, distraction and reduction forces within the construct, to a greater extent than plate systems. The incidence of postoperative radiculopathy was similar to that seen with plate systems. CONCLUSIONS: These data indicate that posterior cervical stabilization with polyaxial screw-rod fixation is a safe, straightforward technique that appears to offer some advantages over existing methods of fixation. Results appear to be durable at 1-year follow-up. Benefits are more significant with longer constructs, especially those extending to the occiput or crossing the cervicothoracic junction.     

A biomechanical analysis of C2 corpectomy constructs.

BACKGROUND CONTEXT: Reconstruction of C2 after tumor destruction and resection remains a significant challenge. Most constructs use a strut graft with plate or screw fixation. A novel C2 prosthesis (cage/plate construct) combining a titanium mesh cage with bilateral C1 shelves and a T-plate has been used successfully in 18 patients. Supplemental posterior instrumentation includes C0-C3 or C1-C3 fixation. Biomechanical comparisons of this C2 prosthesis with traditional fixation options have not been reported. PURPOSE: To investigate and compare the stability of the novel cage/plate construct with a conventional strut graft and plate construct. STUDY DESIGN: An in vitro, cadaveric biomechanical study of C2 replacement constructs. METHODS: Seven fresh-frozen cadaveric human spines (C0-C5) were tested intact. Next, the cage/plate and strut graft/plate constructs were tested with occiput-C3 and C1-C3 posterior instrumentation. Pure moment loads (up to 1.5 Nm) were applied in flexion/extension, lateral bending, and axial rotation. Motion was evaluated using a three-camera motion analysis system. Statistical significance was evaluated using one-way repeated measures analysis of variance with Student-Newman-Keuls post hoc pairwise comparisons. RESULTS: All constructs provided a statistically significant decrease in motion in this C2 corpectomy model as compared with the intact condition. There was no statistical difference in C1-C3 motion between the four constructs in lateral bending, regardless of whether the occiput was included in the posterior fixation. Other significant differences were detected in flexion-extension and axial rotation, and these differences were dependent upon the type of anterior reconstruction and whether the occiput was included in the posterior fixation. CONCLUSIONS: Under acute loading conditions, both the cage/plate and strut graft/plate constructs provided initial stability beyond that of the intact specimen. For some reconstructions the occiput does not need to be included in the posterior instrumentation in order to obtain equivalent stability across the C1-C3 spinal space.     

多节段颈椎骨折脱位的诊治分析

目的 探讨颈椎多节段骨折脱位的临床特点和诊治方法。方法 对1988～2001年43例(男38例,女5例)多节段颈椎骨折脱位患者的影像学资料及临床表现进行回顾分析。结果 连续多节段损伤为36例,其中32例损伤位于下颈椎;不连续多节段损伤为7例,其中有5例为上颈椎伴下颈椎损伤;损伤部位为椎体31例,椎板25例,棘突9例,椎弓4例,横突5例,关节突5例;多见的受累节段为C4、C5、C6和C7;屈曲压缩型占60．5％。行颈前路椎体大块切除脊柱稳定重建21例,后路椎板减压加关节突钢板内固定10例,前、后路联合减压颈椎稳定重建2例;保守治疗10例。结论 颈椎多节段损伤多为屈曲压缩型,连续型损伤多见,不连续型损伤少见;连续型多节段损伤多为下颈椎损伤;不连续型多节段损伤多数为寰、枢椎损伤合并下颈椎损伤;多节段颈椎损伤中不稳定节段及脊髓受损平面均位于下颈椎;手术应在减压的同时重建脊柱的稳定性。