Multilevel Cervical Corpectomy Research Articles

Anterior cervical transpedicular screw fixation system in subaxial cervical spine: A finite element comparative study.

Multilevel cervical corpectomy has raised the concern among surgeons that reconstruction with the anterior cervical screw plate system (ACSPS) alone may fail eventually. As an alternative, the anterior cervical transpedicular screw (ACTPS) has been adopted in clinical practice. We used the finite element analysis to investigate whether ACTPS is a more reasonable choice, in comparison with ACSPS, after a 2-level corpectomy in the subaxial cervical spine. These 2 types of implantation models with the applied 75 N axial pressure and 1 N • m pure moment of the couple were evaluated. Compared with the intact model, the range of motion (ROM) at the operative segments (C4–C7) decreased by 97.5% in flexion-extension, 91.3% in axial rotation, and 99.3% in lateral bending in the ACTPS model, whereas it decreased by 95.1%, 73.4%, 96.9% in the ACSPS model respectively. The ROM at the adjacent segment (C3/4) in the ACTPS model decreased in all motions, while that of the ACSPS model increased in axial rotation and flexion-extension compared with the intact model. Compared to the ACSPS model, whose stress concentrated on the interface between the screws and the titanium plate, the stress of the ACTPS model was well-distributed. There was also a significant difference between the maximum stress value of the 2 models. ACTPS and ACSPS are biomechanically favorable. The stability in reducing ROM of ACTPS may be better and the risk of failure for internal fixator is relatively low compared with ACSPS fixation except for under lateral bending in reconstruction the stability of the subaxial cervical spine after 2-level corpectomy.

Clinicoradiological Outcome of 3 or More Levels of Anterior Cervical Corpectomy and Reconstruction.

Studies reporting multilevel anterior cervical corpectomy (>2 levels) and reconstruction in patients with long-segment anterior cervical compression are few and surgical outcomes are variable with increased surgical morbidity and a high incidence of graft-related complications. The aim of this study is to evaluate the effectiveness and safety of cervical corpectomy and anterior reconstruction of 3 or more levels in patients with long-segment anterior cervical compression. We retrospectively reviewed patients who had undergone 3 or more levels of anterior cervical corpectomy and reconstruction from 2014 to 2018. Clinical and radiological parameters such as Nurick grading, modified Japanese Orthopedic Association (mJOA) score, cervical segmental angle, cervical sagittal angle, graft subsidence, and fusion rate were evaluated preoperatively and at a 2-year follow-up. Patients were divided into 2 groups according to their anterior reconstruction, either with fibular strut autogenous graft or titanium mesh cage and rigid anterior cervical plating for subgroup analysis. Patients whose bone stock was found to be poor had undergone posterior instrumentation as a staged procedure. There were 48 patients (mean age: 58.17 years) in the cohort: 42 had undergone 3-level and 6 had undergone 4-level cervical corpectomy with an ossified posterior longitudinal ligament and multilevel cervical spondylotic myelopathy being the main surgical indications. C5 to C7 corpectomy was most common. Of the cohort, 83.4% had standalone anterior reconstruction and only 8 patients (16.6%) had supplementation with posterior instrumentation. Our subgroup analysis showed statistically significant change in Nurick grading, mJOA score, cervical segmental angle, and sagittal angle in both groups at a 2-year follow-up (P < .05). Overall fusion rate was 89.5%. Decreased incidence of graft subsidence, statistically significant less graft subsidence (P = .002) and a higher fusion rate (P = .001) were noted in titanium mesh cage group at 2-year follow-up. Multilevel anterior cervical corpectomy and reconstruction is a safe and efficacious procedure. A titanium mesh cage filled with autogenous bone graft and a rigid anterior cervical plate gives best results. Posterior instrumentation should be considered along with a multilevel cervical corpectomy construct in patients with poor bone stock. 4.

Stereotactic navigation in anterior cervical spine surgery: surgical setup and technique.

Intraoperative stereotactic navigation in spine surgery is quickly becoming popularized for accurate placement of spinal instrumentation as well as assisting in the verification of anatomic landmarks. Navigation is less commonly utilized in anterior cervical spine surgery due to instrumentation being able to be placed under direct visualization. The utility of navigation in anterior cervical spine surgery is its ability to aid in the verification of anatomic location, particularly when anatomy is distorted or pathology comes close to critical neurovascular structures. We present a technique guide for anterior cervical spine navigation that we have applied at our institution and have found to be very beneficial in select patients, particularly those with complex anatomy, large body mass index, undergoing revision surgery, sustained spinal trauma and those patients with severe anterior ossification where depth or medial-lateral landmarks are difficult to visualize. We describe utilization of the technique using a case examples and specifically in a patient with significant ossification of the posterior longitudinal ligament and severe spinal cord compression that underwent multilevel cervical corpectomy. The described technique was found to be reproducible and effective, allowing cervical spine surgeons to perform more complex or minimally invasive procedures with safety and accuracy. We emphasize that navigation does not replace knowledge of anatomy or technical aspects of the procedure.

Complications exclusive to long strut grafts used following multilevel cervical corpectomy: Utilization of advanced imaging techniques.

When surgical decompression of cervical spine is considered, multilevel cervical corpectomy with long strut grafts is the preferred treatment. This procedure is used in a variety of pathologies including degenerative disease, tumors, trauma and infection. Corpectomy with interbody grafting helps in adequate spinal canal and neural decompression compared to multilevel discectomy, which could be difficult as well as inadequate. Fibular/iliac strut grafts are used for reconstruction along with a stabilizing hardware in this procedure. So far, complete imaging spectrum of complications exclusive to strut graft has not been reported in the literature. This pictorial essay presents complications exclusive to the strut graft, utility of advanced imaging in diagnosis and a brief note on the clinical management of complications.

Cervical reconstruction techniques. After adequate selection of the patient report of a series of 34 patients treated with winged expandable cages.

After single or multilevel cervical corpectomy for the treatment of different diseases, many surgical options have been proposed over the years. As a single device, a winged expandable titanium cage (WETC) has been developed. We report the use of this device and our clinical results at 24months of follow-up in a prospective series of 34 patients who underwent single or multilevel corpectomy for the treatment of cervical spondylosis. Thirty-four consecutive patients underwent single or multilevel cervical corpectomy followed by the insertion of a WETC for the treatment of cervical spondylosis at Department of Neurology and Psychiatry "Sapienza" University of Rome, Italy, from May 2011 to May 2013. Patients affected by cervical spondylosis with cervical lordosis >0° were included. Patients affected by cervical lordosis <0°, osteoporosis, or other cervical diseases were excluded. The mean postsurgical Nurick's grade was significantly lower than the mean presurgical Nurick's grade (mean=0.98 for postsurgical Nurick's grade and mean=2.42 for presurgical Nurick's grade). Four patients (11.7%) presented subsidence respectively of 1, 2, 2, and 3mm at 24months of radiological follow-up. Postoperative complications occurred in five patients (14.7%). Our case series at 24months of follow-up demonstrates that the use of a WETC obtains good clinical results after single or multiple corpectomy in patients not affected by osteoporosis who do not require cervical lordosis correction. During the insertion of the device, an adequate preparation of the end plates is suggested and their over distraction should be avoided.

Biomechanics of adjacent segments after a multilevel cervical corpectomy using anterior, posterior, and combined anterior-posterior instrumentation techniques: a finite element model study

Background contextAdjacent segment degeneration (ASD) after cervical fusion is a clinical concern. Despite previous studies documenting the biomechanical effects of multilevel cervical fusion on segments immediately superior and inferior to the operative segments, the pathogenesis of the initiation of degeneration progression in neighboring segments is still poorly understood. PurposeTo test the hypothesis that changes in range of motion, disc stresses, and facet loads would be highest at the superior adjacent segment (C3–C4) after anterior C4–C7 corpectomy and fusion and that these changes would be the least in anterior fixation and the greatest in posterior or combined anterior-posterior instrumentation techniques. Study designA finite element (FE) analysis of adjacent vertebral segment biomechanics after a two-level corpectomy fusion with three different fixation techniques (anterior, posterior, and combined anterior-posterior). MethodsA previously validated three-dimensional FE model of an intact C3–T1 segment was used. From this intact model, three additional instrumentation models were constructed using anterior (rigid screw-plate), posterior (rigid screw-rod), and combined anterior-posterior fixation techniques after a C4–C7 corpectomy and fusion. Motion patterns, disc stresses, and posterior facet loads at the levels cephalad and caudal to the fusion were assessed. ResultsRange of motion, disc stresses, and posterior facet loads increased at the adjacent segments. Use of posterior fixation, whether alone or in combination with anterior fixation, infers higher changes in segmental motion, disc stresses, and posterior facet loads at adjacent segments compared with the use of anterior fixation alone. The superior C3–C4 motion was most affected during lateral bending and the inferior C7–T1 motion was most affected during flexion, whereas both superior C3–C4 and inferior C7–T1 motions were least affected during extension. However, disc stresses and facet loads were most affected during extension. Hence, it is speculated that the most remodeling changes in discs and facets might be related to the least changes in extension motion. ConclusionsBiomechanical factors such as increased mechanical demand and motion that have been associated with the development of ASD progression are highest in the segment immediately superior to the fusion. These changes are even more pronounced when the fixation technique involves the addition of posterior instrumentation, thereby supporting the hypothesis of the present study. Increased degrees of stiffening of the fused segments not only may lead to degenerative changes in the disc but may also predispose the segments to premature facet degeneration. Over subsequent time period, any remaining construct micro-motion is further eliminated with fusion of the posterior facet joints and the remaining regions in the disc space also filled in with bone, which eventually results in a circumferential type of fusion. After a circumferential fusion, authors, however, speculate that the role of instrumentation in ASD progression might not be significant. In fact, sufficient evidence to support this speculation is still lacking in the literature.

Corpectomy versus discectomy for the treatment of multilevel cervical spine pathology: a finite element model analysis

After multilevel fusions, construct failure because of pseudoarthrosis and instrumentation complications is a well-recognized clinical problem. Little is known about the biomechanics governing the cervical spine after different anterior reconstruction techniques, specifically the number of bone grafts and screws used and whether discectomies versus corpectomies have been performed. A few research groups have compared the efficacy of corpectomy and discectomy procedures under common testing conditions; however, no quantitative stress measurements at graft-end plate and bone-screw interfaces have been reported to date. To test the hypothesis that increasing the number of bone grafts and screws would yield a more stable construct and decrease the stresses at the graft-end plate and bone-screw interfaces. Stability of fusion constructs with three different multilevel reconstruction techniques. A previously validated C3-T1 intact finite element model was modified to evaluate three different anterior C4-C7 fusion models: a two-level corpectomy alone (one graft and four screws), a corpectomy-discectomy (two grafts and six screws), and a three-level discectomy alone (three grafts and eight screws). Two unicortical screws were placed parallel to the corresponding end plates inside the vertebral bodies-C4 and C7 for the corpectomy alone; C4, C6, and C7 for the corpectomy-discectomy; and C4, C5, C6, and C7 for the discectomy alone. Range of motion, graft stresses, end plate stresses, and bone-screw stresses were evaluated. Although total construct motion decreased with an increasing number of bone grafts and screws, this was not significantly different between reconstruction techniques. Stresses in the bone grafts, end plates, and bone near screws decreased as a result of increasing the number of bone grafts and screws, thereby confirming the present study hypothesis. Although the chances of pseudarthrosis have been shown to be lower after multilevel cervical corpectomy versus discectomy, because of fewer bone-graft interfaces required for healing, this benefit should be weighed against the higher bone-screw stresses, operating time, blood loss, and costs associated with corpectomy. Future biomechanical studies focusing on corpectomy and discectomy procedures in similar testing protocols are warranted to compare the findings presented here.

Biomechanical comparison of anterior cervical spine instrumentation techniques with and without supplemental posterior fusion after different corpectomy and discectomy combinations

The objective of this study was to compare the stiffness and range of motion (ROM) of 4 cervical spine constructs and the intact condition. The 4 constructs consisted of 3-level anterior cervical discectomy with anterior plating, 1-level discectomy and 1-level corpectomy with anterior plating, 2-level corpectomy with anterior plating, and 2-level corpectomy with anterior plating and posterior fixation. Eight human cadaveric fresh-frozen cervical spines from C2-T2 were used. Three-dimensional motion analysis with an optical tracking device was used to determine motion following various reconstruction methods. The specimens were tested in the following conditions: 1) intact; 2) segmental construct with discectomies at C4-5, C5-6, and C6-7, with polyetheretherketone (PEEK) interbody cage and anterior plate; 3) segmental construct with discectomy at C6-7 and corpectomy of C-5, with PEEK interbody graft at the discectomy level and a titanium cage at the corpectomy level; 4) corpectomy at C-5 and C-6, with titanium cage and an anterior cervical plate; and 5) corpectomy at C-5 and C-6, with titanium cage and an anterior cervical plate, and posterior lateral mass screw-rod system from C-4 to C-7. All specimens underwent a pure moment application of 2 Nm with regards to flexion-extension, lateral bending, and axial rotation. In all tested motions the statistical comparison was significant between the intact condition and the 2-level corpectomy with anterior plating and posterior fixation construct. All other statistical comparisons between the instrumented constructs were not statistically significant except between the 3-level discectomy with anterior plating and the 2-level corpectomy with anterior plating in axial rotation. There were no statistically significant differences between the 1-level discectomy and 1-level corpectomy with anterior plating and the 2-level corpectomy with anterior plating in any tested motion. There was also no statistical significance between the 3-level discectomy with anterior plating and the 2-level corpectomy with anterior plating and posterior fixation. This study demonstrates that segmental plate fixation (3-level discectomy) affords the same stiffness and ROM as circumferential fusion in 2-level cervical spine corpectomy in the immediate postoperative setting. This obviates the need for staged circumferential procedures for multilevel cervical spondylotic myelopathy. Given that the posterior segmental instrumentation confers significant stability to a multilevel cervical corpectomy, the surgeon should strongly consider the placement of segmental posterior instrumentation to significantly improve the overall stability of the fusion construct after a 2-level cervical corpectomy.

The Incidence of C5 Palsy After Multilevel Cervical Decompression Procedures

Retrospective review of 750 consecutive multilevel cervical spine decompression surgeries performed by a single spine surgeon. To determine the incidence of C5 palsy in a large consecutive series of multilevel cervical spine decompression procedures. Palsy of the C5 nerve is a well-known potential complication of cervical spine surgery with reported rates ranging from 0% to 30%. The etiology remains uncertain but has been attributed to iatrogenic injury during surgery, tethering from shifting of the spinal cord, spinal cord ischemia, and reperfusion injury of the spinal cord. We included patients undergoing multilevel cervical corpectomy, corpectomy with posterior fusion, posterior laminectomy and fusion, and laminoplasty. Exclusion criteria included lack of follow-up data, spinal cord injury preventing preoperative or postoperative motor testing, or surgery not involving the C5 level. Incidence of C5 palsy was determined and compared to determine whether significant differences existed among the various procedures, patient age, sex, revision surgery, preoperative weakness, diabetes, smoking, number of levels decompressed, and history of previous upper extremity surgery. Of the 750 patients, 120 were eliminated on the basis of the exclusion criteria. The 630 patients included in the analysis consisted of 292 females and 338 males. The mean age was 58 years (range, 19-87). The incidence of C5 nerve palsy for the entire group was 42 of 630 (6.7%). The incidence was highest for the laminectomy and fusion group (9.5%), followed by the corpectomy with posterior fusion group (8.4%), the corpectomy group (5.1%), and finally the laminoplasty group (4.8%), although these differences did not reach statistical significance. There was a significantly higher incidence in males (8.6% vs. 4.5%, P = 0.05). Incidence of C5 nerve palsy after cervical spine decompression was 6.7%. This is consistent with previously published studies and represents the largest series of North American patients to date. There is no statistically significant difference in incidence of C5 palsy based on surgical procedure, although there was a trend toward higher rates with laminectomy and fusion.

Biomechanical Evaluation of Transfacet Screw Fixation for Stabilization of Multilevel Cervical Corpectomies

Cadaveric biomechanical investigation. To test the feasibility of transfacet screws as a minimally invasive posterior fixation device for the cervical spine by comparing the biomechanical stability of transfacet screws to lateral mass screws and rods in a multilevel cervical corpectomy model. Minimally invasive surgery (MIS) of the spine has gained increasing acceptance and popularity. However, a minimally invasive means of instrumenting the posterior cervical spine has yet to be discovered. Posterior transfacet screws have been described as a means of posterior fixation. In addition, they have the potential of being placed percutaneously through stab incisions. However, validation of transfacet screws in an unstable cervical model in which posterior instrumentation may be necessary has not been carried out till date. Sixteen cadaveric cervical spines were randomized to transfacet or lateral mass instrumentation groups. The spines were tested in the following conditions: (a) intact, (b) after multilevel corpectomies with strut graft placement with stand-alone posterior fixation, and (c) with an additional anterior plate over the strut graft. Corpectomy site loading was measured with a custom-designed strut graft. Data were collected for spinal stiffness, range of motion, and strut graft loading, and was analyzed using 2-way analysis of variance (P<0.05). Stand-alone transfacet screw fixation was found to provide inferior spinal stability and resulted in increased spinal motion and graft loading compared with the other constructs (P<0.05 for all). It is unclear what kind of mechanical stiffness is necessary to stabilize the cervical spine and obtain solid fusion. However, decreased stability and increased graft loading suggest that transfacet screws may not be the ideal method of posterior fixation to supplement multilevel anterior cervical corpectomies and fusions despite their potential as a minimally invasive method for posterior cervical instrumentation.

Biomechanical effects of anterior, posterior, and combined anterior-posterior instrumentation techniques on the stability of a multilevel cervical corpectomy construct: a finite element model analysis

Background contextMultilevel corpectomy, with or without anterior instrumentation, has been associated with both graft and anterior screw-plate complications. The addition of posterior instrumentation after anterior fixation has been shown to increase the overall stiffness of fused segments and decrease the likelihood of instrumentation failure. Little biomechanical information exists for providing guidance in the selection of an appropriate instrumentation technique after a multilevel cervical corpectomy. Clinical studies have also been inconclusive in choosing an optimum fixation strategy. PurposeTo test the hypothesis that combined anterior-posterior fixation would lower the stresses on the bone-screw interfaces observed after an isolated anterior fixation and on the graft–end plate interfaces observed after an isolated posterior fixation. Study designA finite element (FE) analysis of a C4–C7 corpectomy fusion with three different fixation techniques: anterior, posterior, and combined anterior-posterior. MethodsA previously validated three-dimensional FE model of an intact C3–T1 segment was used. From this intact model, three additional instrumentation models were constructed using anterior (rigid screw-plate), posterior (rigid screw-rod), and combined anterior-posterior fixation techniques following a C4–C7 corpectomy fusion. Construct stability at the cephalad and caudal levels of the corpectomy was assessed. ResultsBiomechanical comparisons between these instrumentation techniques show the least amount of construct motion in the combined anterior-posterior instrumentation model. The use of both anterior and posterior fixation shields the graft–end plate and screw-bone interfaces from peak stresses as compared with an isolated anterior or an isolated posterior fixation, thereby supporting the hypothesis of this study. ConclusionsA combined fixation technique should be balanced against increased operating room time and surgery costs because of dual anterior and posterior fixation and the increased risk of long anterior plating, such as dysphasia, plate or screw dislodgement, or migration. Our study suggests that the use of posterior fixation, whether alone or in combination with anterior fixation, infers comparable stability. Further studies are warranted to identify whether the current findings are consistent with other biomechanical studies.

Risk Factors for Early Reconstruction Failure of Multilevel Cervical Corpectomy With Dynamic Plate Fixation

Retrospective case series. To investigate risk factors for early reconstruction failure of multilevel cervical corpectomy with dynamic plate fixation. For anterior cervical decompression and fusion, reinforcement by plate fixation was performed to decrease early reconstruction failure and to increase the fusion rate. However, a relatively high complication rate such as graft dislodgement, has been reported in patients undergoing multilevel corpectomy and reconstruction. Risk factors associated with early reconstruction failure have not been explicitly described. In 30 instrumented multilevel corpectomy and reconstruction, medical records and radiographic studies were reviewed to investigate risk factors with regard to sagittal alignment of the cervical spine, graft subsidence, screws used in fixation, endplate preparation, and intermediate screw for fibular graft. Reconstruction failures included anterior slipping at the bottom of the graft in 2 cases, fracture of the C7 vertebral body in 2 cases, and pullout of a screw in 2 cases. Four patients were found to have nonunion of the graft at the final follow-up, but none had experienced early reconstruction failure.On radiologic measurement, the fusion area lordotic angle after surgery in the patients with reconstruction failures was significantly larger than that of the patients with no complications. The postoperative C2-C7 lordotic angles of the patients with reconstruction failure were also larger, but this trend was not statistically significant. No other factor, such as age and gender, type of screw used, intermediate screw or preservation of the endplates was related to reconstruction failures in this study. Postoperative cervical hyperlordosis may adversely affect graft stability in the early postoperative period of the surgery of corpectomy and reconstruction with dynamic plate fixation.

The stabilizing potential of anterior, posterior and combined techniques for the reconstruction of a 2-level cervical corpectomy model: biomechanical study and first results of ATPS prototyping.

Clinical studies reported frequent failure with anterior instrumented multilevel cervical corpectomies. Hence, posterior augmentation was recommended but necessitates a second approach. Thus, an author group evaluated the feasibility, pull-out characteristics, and accuracy of anterior transpedicular screw (ATPS) fixation. Although first success with clinical application of ATPS has already been reported, no data exist on biomechanical characteristics of an ATPS-plate system enabling transpedicular end-level fixation in advanced instabilities. Therefore, we evaluated biomechanical qualities of an ATPS prototype C4-C7 for reduction of range of motion (ROM) and primary stability in a non-destructive setup among five constructs: anterior plate, posterior all-lateral mass screw construct, posterior construct with lateral mass screws C5+C6 and end-level fixation using pedicle screws unilaterally or bilaterally, and a 360° construct. 12 human spines C3-T1 were divided into two groups. Four constructs were tested in group 1 and three in group 2; the ATPS prototypes were tested in both groups. Specimens were subjected to flexibility test in a spine motion tester at intact state and after 2-level corpectomy C5-C6 with subsequent reconstruction using a distractable cage and one of the osteosynthesis mentioned above. ROM in flexion-extension, axial rotation, and lateral bending was reported as normalized values. All instrumentations but the anterior plate showed significant reduction of ROM for all directions compared to the intact state. The 360° construct outperformed all others in terms of reducing ROM. While there were no significant differences between the 360° and posterior constructs in flexion-extension and lateral bending, the 360° constructs were significantly more stable in axial rotation. Concerning primary stability of ATPS prototypes, there were no significant differences compared to posterior-only constructs in flexion-extension and axial rotation. The 360° construct showed significant differences to the ATPS prototypes in flexion-extension, while no significant differences existed in axial rotation. But in lateral bending, the ATPS prototype and the anterior plate performed significantly worse than the posterior constructs. ATPS was shown to confer increased primary stability compared to the anterior plate in flexion-extension and axial rotation with the latter yielding significance. We showed that primary stability after 2-level corpectomy reconstruction using ATPS prototypes compared favorably to posterior systems and superior to anterior plates. From the biomechanical point, the 360° instrumentation was shown the most efficient for reconstruction of 2-level corpectomies. Further studies will elucidate whether fatigue testing will enhance the benefit of transpedicular anchorage with posterior constructs and ATPS.

The Use of Expandable Cages in Patients Undergoing Multilevel Corpectomies for Metastatic Tumors in the Cervical Spine

Expandable cages have been used successfully to reconstruct the anterior spinal column in the treatment of traumatic, neoplastic, infectious, and degenerative spine disease. To the best of our knowledge, no studies report the results of the use of expandable cages in patients undergoing multilevel corpectomies for cervical spine metastatic disease. We report our experience with the use of expandable cages in this subgroup of patients.From August 2006 to May 2008, 5 patients presenting with myelopathy, pain, and/or radiculopathy secondary to metastatic disease of the cervical spine underwent multilevel cervical corpectomies and placement of expandable cages in our institution. All procedures were supplemented with an anterior cervical plate and with posterior instrumentation to achieve a 360 degrees fusion. A visual analog scale (VAS), Nurick grade, Frankel grade, American Spinal Injuries Association (ASIA) grade, and Ranawat grade were used to evaluate patients pre- and postoperatively. The mean follow-up period was 13.2 months. Three patients underwent a 2-level corpectomy, 1 a 3-level corpectomy, and 1 a 4-level corpectomy. Postoperative imaging studies showed that all patients had correction of preoperative kyphosis. The mean VAS score was reduced from 6.4 to 1. All other indices of spinal cord injury measured improved postoperatively or were stabilized. Postoperative imaging studies showed stable constructs in 4 patients.The use of expandable cages in multilevel corpectomies for the treatment of metastatic cervical spine disease appears to be a safe and effective way to reconstruct the anterior column of the cervical spine, preventing further neurologic deterioration.

Steroids and Risk Factors for Airway Compromise in Multilevel Cervical Corpectomy Patients

Prospective, randomized, double-blind study. To evaluate intravenous corticosteroids in preventing delayed extubation after multilevel corpectomy and strut graft reconstructive procedures and to identify risk factors for delayed extubation in these patients. We performed a prospective, randomized double-blind study in patients undergoing multilevel cervical corpectomy procedures. Our hypothesis was that high-dose perioperative steroids would decrease edema and thus decrease the incidence of delayed extubation. We studied patients undergoing 2- or 3-level anterior cervical corpectomy procedures with anterior strut graft reconstruction. Sixty-six patients were randomized to receive 3 doses of either intravenous dexamethasone (n = 35) or saline (n = 31). The first dose was given before the incision, with subsequent doses given 8 and 16 hours later. Patients remained intubated until postoperative day 1, at which time a cuff leak test was performed by the anesthesiology attending. If a leak was present, the patient was extubated. If not, the test was repeated each postoperative day until a leak was present, indicating a patent airway. Five of 35 (14%) in the steroid group and 6 of 31 (19%) in the saline group required delayed extubation (P = 0.22). There were no statistical differences in preoperative parameters of age, gender, diagnosis, smoking history, BMI, number of operative levels, or preoperative American Society of Anesthesiologists rating between the 2 groups. Similarly there were no differences between the groups for duration of anesthesia, intraoperative colloids or crystalloids, intraoperative blood loss, or intraoperative urine output. The data for both groups were pooled to evaluate risk factors for delayed extubation. The only statistically significant risk factor for delayed extubation in this study was female gender (P = 0.0001). Based on our data, we cannot recommend intravenous dexamethasone for prevention of delayed extubation after multilevel anterior cervical corpectomy and strut grafting procedures.

Anterior pedicle screw fixation for multilevel cervical corpectomy and spinal fusion

Prevention of graft dislodgement in multilevel cervical corpectomy and fusion has been an unresolved problem. Anterior plate fixation has a significant failure rate. External support with a halo-vest is uncomfortable for patients. In the present study, we report a new surgical technique of anterior pedicle screw (APS) fixation for multilevel cervical corpectomy and spinal fusion, and describe the safety and utility of the system. After cervical corpectomy, the pedicles on the right side were visualised under oblique fluoroscopy. Guide wires were inserted into the pedicles from the inner wall of the excavated vertebral body until they were hidden in the pedicles. After a fibula autograft was placed, the graft was penetrated in the reverse direction by the guide wires. After drilling and tapping, cannulated screws were inserted into the pedicles through the grafted fibula along the guide wires. In 9 patients with cervical myelopathy, the surgery was accomplished with a fibula autograft using APS fixation. A total of 22 APSs were inserted, and 21 screws were placed precisely in the pedicles. There were no neurovascular complications. Patients were allowed to ambulate without a halo-vest on the second day after the surgery. Post-operatively, no dislodgement of the grated fibula occurred, and all patients improved neurologically. The insertion of APSs is feasible and safe. APS fixation enables us to obtain rigid fixation anteriorly, and we propose that APS fixation is an attractive option for multilevel cervical corpectomy and fusion.

Surgical management of cervical myelopathy: indications and techniques for surgical corpectomy

There are a variety of surgical treatments for cervical spondylotic myelopathy (CSM). Review the indications and techniques for multilevel cervical corpectomy in the treatment of CSM. Cervical corpectomy is effective and relatively safe for the treatment of a variety of diseases of the cervical spine. Indications, surgical considerations, operative positioning, surgical method, and complications avoidance are discussed as a guide to effectively performing this procedure.

Implantation of a distractible titanium cage after cervical corpectomy: technical experience in 20 consecutive cases

This prospective observational study was undertaken to investigate the advantages, the safety, and the drawbacks of reconstructing a cervical corpectomy with a distractible corpectomy cage. According to the author's literature search, this is the second clinical report on a distractible cervical corpectomy cage. 20 Consecutive patients underwent a single- or multi-level cervical corpectomy for spondylotic myelopathy, traumatic fracture, or tumor. The corpectomy defect was reconstructed by means of a distractible titanium cage, and local bone from the corpectomy was layed around the cage for fusion. An anterior cervical plate and/or a posterior lateral mass or pedicle screw fixation was added in all patients. The average follow-up was 14 months, and all patients had at least 12 months of follow-up. No hardware failure occurred in any of the patients. Construct stability was achieved in 19 out of 20 patients (95%) at 12 months postoperatively. The mean regional lordosis was 1 degrees preoperatively, 9 degrees postoperatively, and 7 degrees at the follow-up. Mean neck pain on a VAS was 3.9 preoperatively, and 2.6 at 12 months. There were three perioperative complications: transient neurological worsening in one patient, one transient vocal cord paralysis, and persistent dysphagia in one patient. A single- or multi-level cervical corpectomy can be safely and effectively reconstructed by a distractible titanium cage and local bone graft in combination with anterior cervical plating and/or posterior lateral mass/pedicle screw fixation. Potential advantages of this technique are an unforced cage insertion in its non-distracted position, press-fitting the cage into the corpectomy defect through cage distraction, correction of kyphosis or preservation of local lordosis through cage distraction, and the absence of donor site morbidity. However, the stability rate in the current series did not exceed the fusion rates of auto- or allografts.

Biomechanical Comparison of Cervical Spine Reconstructive Techniques After a Multilevel Corpectomy of the Cervical Spine

An in vitro biomechanical study of several reconstructive techniques after a two-level cervical corpectomy. To evaluate, compare, and quantitate the stability of several reconstructive strategies (anterior, posterior, or anterior/posterior with or without instrumentation) after a multilevel cervical corpectomy. Several clinical and biomechanical studies have questioned the stability of stand-alone long-segment anterior plate fixation after a multilevel (>or=2) corpectomy. The large cantilever forces generated within the stabilized construct, particularly at the caudal screw-bone interface, have led to plate and screw dislodgement and the need for further surgical intervention. The addition of posterior segmental instrumentation has been shown to improve overall stability and decrease local stresses on the anterior fusion construct (graft and plate). Seven fresh-frozen cadaveric human cervical spines (C1-T1) were harvested. The C1-C2 and C7-T1 vertebral bodies were embedded in poly-methylmethacrylate (PMMA). Three VICON cameras tracked three-dimensional segmental motions at the ends of the fusion construct after a two-level corpectomy and placement of a strut graft with or without instrumentation. Pure moments (flexion/extension, lateral bending, and axial rotation) were applied to the C1 level of each specimen. The motion segments were loaded to a maximum of 2 Nm using dead weights. Testing was first performed on the intact specimens. Then, a two-level corpectomy at the C4 and C5 levels was performed. A PMMA strut graft was then placed into the corpectomy site. Biomechanical testing was then repeated among three different reconstruction techniques: 1) anterior cervical locking plate (PEAK; Depuy-Acromed, Raynham, MA) with dual unicortical screw fixation at C3 and C6; 2) posterior cervical instrumentation (Summit; Depuy-Acromed) using a 3.0-mm rod with segmental lateral mass screw fixation from C3 to C6; and 3) a combined anterior-posterior instrumentation using the anterior PEAK plate and posterior Summit rod system. In all pure moments tested (flexion/extension/lateral bending/axial rotation) the combined anterior-posterior instrumentation reconstruction model and the posterior-only instrumentation model were significantly more rigid than the anterior-only instrumentation model (P < 0.05). Interestingly, no statistically significant difference was noted between the combined anterior plate/posterior instrumentation model and the posterior instrumentation-only model. The biomechanical results obtained suggest that posterior segmental instrumentation confers significant stability to a multilevel cervical corpectomy regardless of the presence or absence of anterior instrumentation. In cases in which the stability of a multilevel reconstruction procedure is tenuous, the surgeon should strongly consider the placement of segmental posterior instrumentation to significantly improve the overall stability of the fusion construct.

15. Steroids for multi-level cervical corpectomy procedures: do they reduce upper airway edema? A randomized, prospective, double-blind study

15. Steroids for multi-level cervical corpectomy procedures: do they reduce upper airway edema? A randomized, prospective, double-blind study