Anterior fusion for rotationally unstable cervical spine fractures

STUDY DESIGN: A retrospective analysis of 32 rotationally unstable cervical fractures treated by brace, halo vest, or posterior surgical constructs plus fusion is compared with a second, prospective study of 18 similar fractures treated by early anterior discectomy, fusion, and plating. OBJECTIVES: To characterize an often unrecognized fracture pattern and compare various methods of management to identify the most effective treatment. SUMMARY OF BACKGROUND DATA: The rotationally unstable cervical spine fracture (compression-extension Stage 1) involves a hyperextension and lateral flexion injury, resulting in a unilateral pedicle, facet complex, and/or lamina fracture under compression and anterior annular disruption under tension. This fracture pattern allows a rotatory spondylolisthesis of the spine around the axis of the intact lateral mass and facet complex. METHODS: A retrospective review was made of 284 cervical fractures, identifying 32 compression-extension Stage 1 fractures that were treated by a variety of techniques. The results of that study led to a second (prospective) study, in which 18 similar fractures were treated by early anterior discectomy, fusion, and plating. RESULTS: Nonoperative treatment was uniformly unsuccessful. Posterior stabilization and fusion procedures led to unsuccessful results in 45%, related either to late kyphosis because of disc collapse or the inability of midline stabilization procedures to control rotational instability. Anterior fusion resulted in solid union without residual deformity in all cases. All four patients in the prospective study with incomplete cord lesions showed improvement in cord function, as did seven patients who had radiculopathy. CONCLUSION: Although posterior bony injury is the usual radiographic finding, the anterior disc and anterior longitudinal ligament disruption are the more significant injuries and lead to late collapse and kyphotic deformity. Early anterior fusion is recommended in compression- extension Stage 1 cervical spine injuries.     

Severe hyperflexion sprains of the lower cervical spine in adults.

Severe sprains of the cervical spine result from a traumatic rupture of the intervertebral disc and ligaments. Although rare, these lesions may lead to a significant kyphotic deformity if they are not surgically treated. The treatment of such a kyphotic deformity may consist of surgical fixation of the lesion through either an anterior or posterior approach. A retrospective study has been done examining 44 severe cervical sprains in 41 patients surgically treated through a posterior approach, using Roy-Camille plates. With an average followup of 29 months (range, 6-60 months), 73% of the patients recovered a normal range of spinal motion, with either moderate or no pain. No neurologic or vascular complications directly attributable to posterior plating and no secondary kyphosis were observed. A moderate sagittal displacement with kyphotic angulation occurred above the fusion in five patients. Posterior screw plate fixation appears to be a safe and effective treatment for severe hyperflexion sprain of the lower cervical spine in the adult.     

Surgical reconstruction of late post-traumatic thoracolumbar kyphosis

Thirty-four patients underwent surgery for late post-traumatic thoracolumbar kyphosis. Indications for surgery included increasing kyphotic deformity, pain, or increasing neurologic deficit. Procedures included anterior spinal fusion only, posterior spinal fusion only, anterior and posterior fusions as staged procedures, and anterior and posterior fusions under the same anesthetic. Eighteen of the patients with anterior fusions also underwent decompression of the spinal cord by resection of the vertebral body. Stable fusion with halt in progression of deformity was obtained in 33 of the 34 patients by following basic biomechanical principles.     

The fractured cervical spine rendered unstable by anterior cervical fusion.

Anterior interbody grafts are prone to displacement if there is posterior instability or gross deformity of the vertebral body. Twenty-one patients treated with anterior interbody fusion for cervical vertebral fractures and dislocations were studied. Twelve of the fractures were considered unstable preoperatively, and 50% of this group treated with anterior stabilization had graft migration postoperatively. If anterior fusion is used in unstable cervical fractures then posterior stabilization or complete bed rest with effective external stabilization (i.e., tongs or Halo-thoracic brace) for 4 weeks is mandatory. The other alternative is posterior stabilization before anterior decompression. In the presence of posterior instability, anterior interbody fusion alone cannot be recommended as the treatment of choice for cervical fractures.     

Surgical management of the subaxial cervical spine (C3-T1) in rheumatoid arthritis

Summary In the process of skeletal changes in rheumatoid arthritis (RA) the lower cervical spine may characteristically be affected by subluxation, discoligamentous insufficiency and bone resorption. These may cause severe pain and important neurological deficit and necessitate surgical intervention. Out of a series of 122 RA patients who underwent surgery of the cervical spine, in 23 the subaxial cervical spine was operated on. Pain was the leading symptom in all patients. In only six were there no pathological neurological findings, and all showed marked kyphotic deformity of the cervical spine. Fourteen patients were operated by a posterior approach, one by a ventral approach, and in eight patients the surgical procedure consisted of anterior decompression and dorsal stabilization. A mean of 21.3 months after surgery, clinical and radiological evaluation was performed. In two patients the sensomotor deficit improved, and out of 16 patients with cervical myelopathy, nine improved. No pseudoarthrosis was noted, and moderate loss of correction was seen in only three patients. In a subjective evaluation, 14 patients rated their result as good, six as fair and none as poor. In conclusion, following decompression, we noted good recovery from myelopathic symptoms. Sufficient stability in patients with RA is achieved by a combined anterior and posterior approach, the main goal of the anterior approach being decompression by vertebrectomy and that of the posterior approach stabilization by plate and screw fixation.     

Results of ventral spondylodesis of the cervical spine (C2-C7)

The author reports of 130 anterior intercorporeal fusions in unstable and/or displaced injuries of the inferior cervical spine (C2-7). Reduction was achieved preoperatively by progressive skull traction in four-fifths of the cases and in the remainder by gentle manual mobilization just before surgery. As a whole, flexion/extension and rotation were found to be reduced by one-fourth despite compensatory mobility below and above the graft; fusions were well tolerated if only one intervertebral space at the lower cervical spine was involved. Robinsons technique, together with anterior plate fixation, yields immediate stabilization, avoids graft migration and redisplacement of the spine, and provides the best functional outcome.     

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.      

Single-stage Anterior and Posterior Fusion Surgery for Correction of Cervical Kyphotic Deformity Using Intervertebral Cages and Cervical Lateral Mass Screws: Postoperative Changes in Total Spine Sagittal Alignment in Three Cases with a Minimum Follow-up of Five Years

The surgical treatment of cervical kyphotic deformity remains challenging. As a surgical method that is safer and avoids major complications, the authors present a procedure of single-stage anterior and posterior fusion to correct cervical kyphosis using anterior interbody fusion cages without plating, as illustrated by three consecutive cases. Case 1 was a 78-year-old woman who presented with a dropped head caused by degeneration of her cervical spine. Case 2 was a 54-year-old woman with athetoid cerebral palsy. She presented with cervical myelopathy and cervical kyphosis. Case 3 was a 71-year-old woman with cervical kyphotic deformity following a laminectomy. All three patients underwent anterior release and interbody fusion with cages and posterior fusion with cervical lateral mass screw (LMS) fixation. Postoperative radiographs showed that correction of kyphosis was 39° in case 1, 43° in case 2, and 39° in case 3. In all three cases, improvement of symptoms was established without major perioperative complications, solid fusion was achieved, and no loss of correction was observed at a minimum follow-up of 61 months. We also report that preoperative total spine sagittal malalignment was improved after corrective surgery for cervical kyphosis and was maintained at the latest follow-up in all three cases. The combination of anterior fusion cages and LMS is considered a safe and effective procedure in cases of severe cervical kyphotic deformity. Preoperative total spine sagittal malalignment improved, accompanied by correction of cervical kyphosis, and was maintained at last follow-up in all three cases.     

Increased fusion rates with cervical plating for two-level anterior cervical discectomy and fusion

STUDY DESIGN: A retrospective review of all patients surgically treated with a two-level anterior cervical discectomy and fusion with and without anterior plate fixation by a single surgeon. OBJECTIVES: To compare the clinical and radiographic success of two-level discectomy and the effect of anterior cervical plate fixation. SUMMARY OF BACKGROUND DATA: Prior studies of multisegment fusions have shown decreased fusion rates correlating with the number of increased levels. The use of anterior plates for single-level cervical fusions is controversial. However, their use in multilevel fusions may be warranted because of the increased pseudarthrosis rates. METHODS: Over a 6-year period, 60 patients were treated surgically with a two-level anterior cervical discectomy and fusion by the senior author. Thirty-two patients had cervical plates, and 28 underwent fusions without plates. These patients were followed for an average of 2.7 years. Clinical and radiographic follow-up evaluations were performed. RESULTS: Of the 60 patients, 7 had a pseudarthrosis. The pseudarthrosis rates were 0% for patients with plating and 25% for those with no plating. This difference was statistically significant (P = 0.003). No correlation of pseudarthrosis with gender, age, level of surgery, history of tobacco use, or the presence of prior anterior surgery was found. There was significantly less graft collapse (P = 0.0001) in the patients without plates in whom pseudarthrosis developed (1.4 mm) than in those who had fusions with plates (0.3 mm). The amount of kyphotic deformity of the fused segment was 0.4 degree in patients with plating compared with 4.9 degrees in those without plating who developed a pseudarthrosis (P = 0.0001). CONCLUSIONS: The addition of plate fixation for two-level anterior cervical discectomy and fusion is a safe procedure with no significant increase in complication rates. The pseudarthrosis rates are significantly higher in patients treated without plate fixation. No nonunions occurred in the patients treated with plate fixation. There was significantly less disc space collapse and kyphotic deformity with the plated fusions than with the nonplated fusions, in which a pseudarthrosis developed. The complication rates for plated fusions are extremely low and do not differ from those for nonplated fusions.     

Cervical spine loading characteristics in a cadaveric C5 corpectomy model using a static and dynamic plate

Anterior plates are used to increase the initial stability of anterior cervical spine fusions; however, plating has been suggested to cause graft stress shielding, leading to reduced fusion rates. The objectives of this study were to quantify the effects of graft size and plating (static versus dynamic) and the role of the posterior elements on load transmission in anterior cervical fusion. A C5 corpectomy was performed on six human cervical spines (C3-C7). An instrumented height-adjustable graft and dynamic cervical plate were used to measure axial load transmission. Each specimen underwent axial compressive testing with dynamic and static plate configurations, optimal and undersized graft heights, and posterior elements intact and removed. Dynamic plating allowed significantly more load transmission by the graft, particularly in the undersized graft configuration. The posterior elements play a significant role in load transmission.     

前路ALPS内固定器在胸腰椎爆裂骨折并截瘫治疗中的应用

目的: 讨论脊柱前路手术和前路锁定钢板系统 (AnteriorLockingPlateSystem, ALPS) 治疗胸腰椎爆裂骨折合并截瘫的方法和疗效。方法: 对 35例胸腰椎爆裂骨折合并截瘫的患者行前路手术减压、复位、植骨和ALPS内固定器治疗。结果: 33例获得随访, 大部分患者的神经功能不同程度的恢复, 未见内固定物松动、断裂, 无明显后凸畸形复发。结论: 脊柱前路手术减压充分, 在有椎体间支撑植骨时, ALPS内固定器能提供坚强的固定, 符合生物力学要求。     

A biomechanical evaluation of cervical spinal stabilization methods in a bovine model. Static and cyclical loading

A bovine model was developed for biomechanical evaluation of surgical procedures stabilizing traumatic cervical injuries disrupting the anterior and posterior spinal column. Cervical spinal segments and C4-5 functional spinal units were tested statically, and C4-5 functional spinal units were tested cyclically in evaluation of 1) the intact cervical spine, 2) Rogers' wiring method, 3) Bohlman's triple-wire technique, 4) sublaminar wiring, 5) anterior cervical plate instrumentation, and 6) posterior hook plate stabilization. Anterior cervical plate instrumentation proved inadequate, and was the least rigid, with axial and flexural loading (P less than 0.05). There was no significant difference between each of the three posterior wiring methods, and all generally restored stability to equal that of the uninjured intact cervical spine. Posterior hook plating with an interspinous bone graft serving as an extension block was the most effective method in reducing flexural stress across the injured C4-5 segment (P less than 0.05). Cyclical in vitro testing was the most sensitive method in highlighting mechanical differences between instrumentation systems, particularly with "on-line" continuous measurement of anterior and posterior strains. Anterior cervical plate stabilization does not appear to confer enough stability in cervical facet injuries to obviate the need for posterior cervical stabilization procedures. The recently developed posterior hook plate technique offers biomechanical advantages that should be weighed against the greater technical precision needed for insertion and the increased potential for neurologic and vascular complications.     

Anterior cervical discectomy for one- and two-level cervical disc disease: the controversy surrounding the question of whether to fuse,plate, or both

Since the introduction of anterior approaches to the cervical spine for the surgical treatment of degenerative disc disease, controversies have developed regarding the necessity of fusion following anterior cervical discectomy, the use of allografts instead of autologous bone for fusion, and, recently, the employment of anterior cervical plating systems in addition to fusion for uncomplicated disc disease. We reviewed seven clinical papers dealing with these issues; these articles surveyed a total of 1153 patients. Several observations can be made from these reviews. First, there is little or no difference in clinical outcome following single-level anterior discectomy, whether a fusion is performed or not, regardless of whether the operation was for soft discs or osteophytes. Second, most patients who underwent two-level discectomies had outcomes comparable to patients who underwent surgery at one level, regardless of whether they were fused or not. Data from four prospective randomized clinical studies in addition to multiple non-randomized or retrospective studies support these conclusions. Although the incidence of complications such as persistent postoperative posterior cervical and shoulder pain and kyphotic deformities is higher in unfused patients (and is quite significant in some series), the advantages conferred by interbody fusion such as biomechanical stability, decreased incidence of kyphotic deformity, and decreased pain are offset by graft and donor-site morbidity. Specific indications for fusion include multi-level discectomies, significant straightening of the cervical spine, failed prior fusions, and trauma. It has been demonstrated that comparable fusion rates can be achieved with allografts rather than harvested autologous bone. The advantages of autografts over allografts are relatively slight in most patients who undergo anterior fusion for one- or two-level disc disease, although patients with impaired healing, significant osteopenia, or concomitant microvascular disease, such as chronic smokers, may benefit from autologous bone. The use of allografts avoids donor-site morbidity in patients without these problems. Anterior cervical plates are useful for cases of instability requiring fusion (such as trauma); these implants may decrease reoperation rates and the incidence of delayed instability in select cases. However, the cost-effectiveness of their generalized use for uncomplicated cervical disc disease has not been demonstrated. In conclusion, a general statement regarding the optimal surgical treatment for cervical disc herniations using anterior approaches is difficult to make with this limited review. Surgeons' experience and familiarity with a particular approach are probably the most important factors in ensuring successful outcomes.     

Complications in three-column cervical spine injuries requiring anterior-posterior stabilization.

A study was undertaken to elicit the hidden factors that, when identified, would signal the presence of cervical spine instability. Data were derived from the records and radiographs of 21 patients having sustained traumatic injury to the lower cervical spine (C3-C7) and who failed a single-stage posterior stabilization procedure necessitating a second (or combined) anterior-posterior arthrodesis. Mechanism of injury most frequently identified in this group was the distraction-flexion (locked facets) pattern (nine patients) and the "tear drop" compression-flexion injury pattern (seven patients). All 21 patients underwent a posterior wiring and bone graft stabilization procedure with persistent postoperative instability. Thus, failure to recognize the presence of "three-column" instability, the sine qua non of this group, resulted in the failure of posterior tension band stabilization as a means of gaining cervical spine stability. Three-column cervical spine instability is suspected in the presence of: 1) retrolisthesis and angulation of the superior vertebra on the next inferior vertebra; 2) distraction of the posterior interspinous ligaments sufficient to allow subluxation or dislocation of the facets; in conjunction with 3) a "shear" dislocation of one vertebra on another. Anterior shearing force through the disc space is capable of disrupting the intervertebral disc, along with disruption of the anterior and posterior longitudinal ligaments, each contributing to the presence of anterior and middle column cervical spine instability.     

Cervical spine stabilization. A three-dimensional, biomechanical evaluation of rotational stability, strength, and failure mechanisms

The three-dimensional rotational biomechanical properties of several different types of posterior stabilizing procedures are reported. A severe ligamentous and bony injury was simulated with three vertebral body human cervical spine segments. Good stabilization was noted for all of the repairs in flexion loading. Without polymethylmethacrylate supplementation, none of the repairs was stable in extension. All of the repairs provided reasonable stabilization for lateral bending except for the posterior wiring without methacrylate, and all but the posterior wiring and facet fusion provided reasonable stabilization against axial rotation loading. The supplementation of all of these repairs with polymethylmethacrylate added considerably to the stability of all the constraints. These findings may be useful in clinical decision-making for determining the kind of repairs and postoperative brace protection to use.     

Postlaminectomy kyphosis. Causes and surgical management.

Postlaminectomy instability of the cervical spine can be managed either anteriorly or posteriorly. The posterior procedures that have been described are best performed at the time of the original decompressive procedure. Thus, the development of a kyphotic deformity is prevented. Generally, it is technically easier to achieve anterior stabilization and arthrodesis if a postlaminectomy kyphosis develops.     

The effect of cervical plating on single-level anterior cervical discectomy and fusion

The use of anterior plates for single-level cervical fusions is controversial. Previous studies that evaluated single and multiple-level fusions have shown increased and decreased fusion rates when cervical plates are used. The purpose of this study was to compare the clinical and radiographic success of single-level discectomy performed with and without anterior cervical plate fixation. During a 6-year period, 80 patients were surgically treated with a single-level anterior cervical discectomy. Forty-four patients had cervical plates, whereas 36 had fusions without plates (average follow-up, 2.3 years). The pseudarthrosis rates were 4.5% (2 of 44) for patients with plating and 8.3% (3 of 36) without plating. This difference was not significant (p = 0.653). There was no correlation of pseudarthrosis with sex, age, level of surgery, history of tobacco use, or the presence of previous anterior surgery. The amount of graft collapse for patients with plating was 0.75 mm compared with 1.5 mm for those without a plate (p = 0.026). The amount of kyphotic deformity of the fused segment was 1.2 degrees with plating compared with 1.9 degrees for patients without plating (p = 0.079). Ninety-one percent of the patients with plating had good or excellent results compared with 88% in the group without cervical plates, based on Odom's criteria. The addition of plate fixation for single-level anterior cervical discectomy and fusion is safe and not associated with a significant increase in complication rates. The pseudarthrosis rates are not significantly different when a cervical plate is used.     

Distraction extension injuries of the cervical spine

Twenty-four consecutive patients with cervical distraction extension injuries were retrospectively reviewed to study the safety and efficacy of various treatment protocols in this type of cervical spine injury. Sixteen of 24 patients with cervical distraction extension injuries underwent surgical stabilization. All patients undergoing surgical stabilization were noted to have a stable fusion at their latest follow-up. There were three instances of surgically related neurologic deterioration as a result of over-distraction of the anterior column interspace at the time of graft placement. The overall mortality rate was 42% in this aged patient population. Anterior reconstruction of the cervical spine with an anterior cervical graft and plate acting as a tension band is the ideal treatment method for stabilization of acute distraction extension injuries involving primarily the soft tissue structures (anterior longitudinal ligament and intervertebral disc). Type 2 injuries, depending on the degree of displacement and the adequacy of closed reduction, may need to be approached initially posteriorly to obtain adequate alignment, followed by an anterior reconstructive procedure. Great care should be taken during anterior graft placement to avoid over-distraction of the spine. If nonsurgical intervention is selected, close regular radiographic follow-up is necessary to detect early vertebral malalignment, which may predispose to spinal cord dysfunction. Older patients sustaining this injury have a high mortality rate.     

The use of plate fixation in anterior surgery of the degenerative cervical spine: a comparative prospective clinical study

The method of anterior mono- or bisegmental cervical spine fusion is a well-established procedure for degenerative conditions of the cervical spine. While the early reports promote fusion with bone graft alone, recent studies report superior results with the addition of anterior plating. The objective of this study was to evaluate the influence of using plates in anterior cervical spine fusion in a prospective study. Fifty candidates for anterior monoor bisegmental cervical spine fusion were randomly and prospectively selected and assigned to a plated and a non-plated group. After a minimum follow-up of 22 months, patients were clinically and radiologically examined. The reduction in pain, improvement in neurology and functional assessment showed a significant improvement in both groups compared to the preoperative values. The total neurological score improved significantly in both groups, but the changes were greater in the group with plates. There was no significant difference between the groups for fusion rating, but graft quality (graft height) was significantly better in the plated group. We conclude that the overall data do not suggest better results with plating in mono- or bisegmental anterior spine fusions. Indications for additional internal fixation are restricted to special conditions with increased instability, insufficient bone quality or inappropriate graft placing.     

Vertebral locking lesion following cervical spine fracture in ankylosing spondylitis

Spine fractures in patients with ankylosing spondylitis frequently extend to all 3 columns, which can lead to displacement and deformity with severe instability. Cervical spine fractures occasionally cause severe kyphotic deformities, such as chin-on-chest deformities. In such cases, the patients typically exhibit a chronic progression of hyperkyphosis after the traumatic event. This article describes a unique case of ankylosing spondylitis associated with an acute chin-on-chest deformity following a spine fracture due to a vertebral locking lesion.A 60-year-old man fell while walking and sustained a compression fracture of the C6 vertebra. Two weeks later, the patient acutely developed an inability to raise his head, difficulties with chewing and swallowing, and a horizontal gaze. Radiographs demonstrated a severe kyphosis in the cervical spine with a locking lesion between the anterior wall of the C5 and C6 vertebrae. The patient also presented with neurological impairment in his hands. Because the anterior approach to the spine was anatomically impossible, halo traction was initially applied under a close observation of neurological symptoms. Three days after halo traction, release of the vertebral locking lesion and realignment of the spine were seen. The patient subsequently underwent spinal fusion using a combined anterior-posterior approach.Postoperatively, neurological dysfunction improved, and solid fusion was confirmed at 6 months. In cases of acute kyphotic deformity following cervical spine fracture in ankylosing spondylitis patients, halo traction followed by circumferential spine fusion is a safe and effective approach for improving the alignment and stability of the spine.