Cervical corpectomy: report of 185 cases and review of the literature

Risk Factors, Incidence and Mortality of Vertebral Artery Injury in Patients Undergoing Anterior Cervical Corpectomy: A Retrospective Large National Data Base Study

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVE

To determine the incidence of vertebral artery injury (VAI), risk factors, intervention, associated complications, and mortality in patients undergoing anterior cervical corpectomy.

METHODS

We performed a retrospective review of the incidence of VAI during anterior cervical corpectomy using the PearlDiver database from 2010-2017. The CPT code 63 081 to identify corpectomy patients. Patient data extracted included, incidence of VAI, demographic factors, intervention, and future complications of death and stroke. The risk were calculated compared with those patients who did not have VAI.

RESULTS

26 126 patients were identified to have undergone cervical corpectomy. Multivariate analysis of risk factors showed that younger age and male sex were associate with higher rate of injury (t = -11.5; P < .0001 and t = 3.8; P = .0001, respectively). Vertebral artery injuries occurred in 78 patients at an incidence of .3%. 11 (14%) VAI patients had a cerebral infarction compared with 1705 (7%) for non-VAI patients (OR = 2.13; 95% CI = [1.18 - 3.85; P = .0179]) during the follow up period. 1-year mortality rates were higher in patients who suffered a VAI (14%) compared to those who did not suffer a VAI (4%; OR = 3.85; CI = [2.04 - 7.14]; P < .0001).

CONCLUSION

Consequence of VAI may not be known for months following the injury. Although the same admission mortality is rare with this injury, there is a significant increase in post-discharge complications. This study suggests that further investigations into long term health risk of VAI is needed.

Anterior cervical corpectomy and fusion with stand-alone cages in patients with multilevel degenerative cervical spine disease is safe

Background

In case of spinal cord compression behind the vertebral body, anterior cervical corpectomy and fusion (ACCF) proves to be a more feasible approach than cervical discectomy. The next step was the placement of an expandable titanium interbody in order to restore the vertebral height. The need for additional anterior plating with ACCF has been debatable and such technique has been evaluated by very few studies. The objective of the study is to evaluate radiographic and clinical outcomes in patients with multilevel degenerative cervical spine disease treated by stand-alone cages for anterior cervical corpectomy and fusion (ACCF).

Methods

Thirty-one patients (66.5 ± 9.75 years, range 53–85 years) were analyzed. Visual Analog Scale (VAS) and the 10-item Neck Disability Index (NDI) were assessed preoperatively and during follow-up on a regular basis after surgery and after one year at least. Assessment of radiographic fusion, subsidence, and lordosis measurement of Global cervical lordosis (GCL); fusion site lordosis (FSL); the anterior interbody space height (ant. DSH); the posterior interbody space height (post. DSH); the distance of the cage to the posterior wall of the vertebral body (CD) were done retrospectively. Mean clinical and radiographic follow-up was 20.0 ± 4.39 months.

Results

VAS-neck (p = 0.001) and VAS-arm (p < 0.001) improved from preoperatively to postoperatively. The NDI improved at the final follow-up (p < 0.001). Neither significant subsidence of the cages nor significant loss of lordotic correction were seen. All patients showed a radiographic union of the surgically addressed segments at the last follow up.

Conclusions

Application of a stand-alone expandable cage in the cervical spine after one or two-level ACCF without additional posterior fixation or anterior plating is a safe procedure that results in fusion. Neither significant subsidence of the cages nor significant loss of lordotic correction were seen.

Trial registration

Retrospectively registered. According to the Decision of the ethics committee, Jena on 25th of July 2018, that this study doesn’t need any registration. https://www.laek-thueringen.de/aerzte/ethikkommission/registrierung/.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04883-5.

Iatrogenic Vascular Injury Associated with Cervical Spine Surgery: A Systematic Literature Review

BACKGROUND

Iatrogenic vascular injury is an uncommon complication of anterior and/or posterior surgical approaches to the cervical spine. Although the results of this injury may be life-threatening, mortality/morbidity can be reduced by an understanding of its mechanism and proper management.

METHODS

We conducted a literature review to provide an update of this devastating complication in spine surgery. A total of 72 articles including 194 cases of vascular lesions following cervical spine surgery between 1962 and 2021 were analyzed.

RESULTS

There were 53 female and 41 male cases (in addition to 100 cases with unreported sex) with ages ranging from 3 to 86 years. The vascular injuries were classified according to the spinal procedures, such as anterior or posterior cervical spine surgery. The interval between the symptom of the vascular injury and the surgical procedure ranged from 0 to 10 years. Only two-thirds of patients underwent intra- or postoperative imaging and the most frequently injured vessel was the vertebral artery (86.60%). Laceration was the most common lesion (41.24%), followed by pseudoaneurysm (16.49%) and dissection (5.67%). Vascular repair was performed in 114 patients. The mortality rate was 7.22%, and 18.04% of patients had 1 or more other complications. Most presumed causes of vascular lesions were by instrumentation/screw placement (31.44%) or drilling (20.61%). Sixteen patients had an anomalous artery. Direct microsurgical repair was achieved in only 15 cases.

CONCLUSIONS

Despite increased anatomical knowledge and advanced imaging techniques, we need to consider the risk of vascular injury as a surgical complication in patients with cervical spine pathologies.

Revision of a Failed C5-7 Corpectomy Complicated by Esophageal Fistula Using a 3-Dimensional-Printed Zero-Profile Patient-Specific Implant: A Technical Case Report

BACKGROUND

Esophageal fistulae are rare, though serious, complications of anterior cervical surgery. Hardware-related issues are important etiologic factors. Patient-specific implants (PSIs) have increasingly been adapted to spinal surgery and offer a range of benefits. Zero-profile implants are a recent development primarily aimed at combating postoperative dysphagia. We report the first use of a 3-dimensional (3D)-printed zero-profile PSI in managing implant failure with migration and a secondary esophageal fistula.

METHODS

A 68-year-old female had a prior C5-7 corpectomy with cage and plate fixation, as well as posterior C3-T1 lateral mass fixation, complicated by anterior plate displacement, resulting in pseudoarthrosis and an esophageal fistula. A 3D-printed zero-profile PSI was designed and implanted as part of a revision procedure to assist in recovery, prevent recurrence, and facilitate bony fusion.

RESULTS

Optimal implant placement was achieved on the basis of preoperative virtual surgical planning. By 1 month postoperatively the patient had significantly improved, with evidence of esophageal fistula resolution and radiographic evidence of optimal implant placement.

CONCLUSIONS

Zero-profile 3D-printed PSIs may combat common and serious complications of anterior cervical surgery including postoperative dysphagia and esophageal fistulae. Further research is required to validate their widespread use for either cervical corpectomy or diskectomy and interbody fusion.

Evaluation of the effectiveness of expandable cages for reconstruction of the anterior column of the spine

PURPOSE

For anterior spine column reconstruction after corpectomy, expandable cages offer solid anterior support and allow correction of deformity, providing excellent primary stability. To provide a larger body of clinical observations concerning the effectiveness of the approach, this retrospective study examines patients treated by corpectomy and reconstruction with an expandable cage for different pathologies.

METHODS

Across 5 years, 39 patients underwent vertebral reconstruction with expandable cages after single (n = 34), double (n = 4), or triple (n = 1) corpectomy. Pathologies were tumors (n = 21), fractures, or deformities in traumatic injuries (n = 14), degenerative pathology (n = 2), and infection (n = 2). Levels were cervical (n = 10), thoracic (n = 14), and lumbar (n = 15). All patients were evaluated clinically and radiographically.

RESULTS

There were no cases of neurologic deterioration. Nurick grade showed significant improvement at 3 months postoperative versus preoperative (p < 0.01). Visual analog scale significantly improved preoperatively versus 3 and 12 months postoperatively (both p = 0). Regional angulation was significantly corrected, from preoperative to 3 and 12 months postoperative, at cervical, thoracic, and lumbar levels. We achieved reconstruction of the normal local anatomy with full recovery of the height of the vertebral body. Six patients (15.4%) had complications and two (5.1%) underwent revision surgery.

CONCLUSIONS

In our experience, expandable cages confer stable anterior support, providing significant improvement of the segmental kyphosis angle and restoration of the original somatic height. Our clinical results are favorable, and the low rate of complications and revision accentuates the expandable cage as a valuable tool to replace the vertebral body in diverse pathologies and different spine levels.

Cervical Spondylotic Myelopathy: When and Why the Cervical Corpectomy?

BACKGROUND

Cervical spondylotic myelopathy (CSM) is a degenerative disease that represents the most common spinal cord disorder in adults. The best treatment option has remained controversial. We performed a prospective study to evaluate the clinical, radiographic, and neurophysiologic outcomes for anterior cervical corpectomy in the treatment of CSM.

METHODS

From January 2011 to January 2017, 60 patients with CSM were prospectively enrolled in the present study. The patients were divided according to the modified Japanese Orthopaedic Association scale (mJOA) score into 2 groups: group A, patients with mild to moderate CSM (mJOA score ≥13); and group B, patients with severe myelopathy (mJOA score <13). Data were collected for each participating subject, including demographic information, symptoms, medical history, radiologic and neurophysiologic features, and functional impairment.

RESULTS

Of the 60 patients, 35 were men (58.3%) and 25 were women (41.7%). Their average age was 57.48 ± 10.60 years. The mean symptom duration was 25.33 ± 16.00 months; range, 3-57 months). Of the 60 patients, 22 had undergone single-level corpectomy and 36 multilevel corpectomy. A significant improvement in the motor evoked potentials was observed in both groups.

CONCLUSIONS

Single- and multilevel corpectomy are valid and safe options in the treatment of CSM. In the present prospective study, a statistically significant improvement in the mJOA score and neurophysiologic parameters was observed for both moderate and severe forms of CSM.

Transoral Endoscopic Approach to Repair Early Pharyngeal Perforations After Anterior Cervical Spine Surgery without Failure of Instrumentation: Our Experience and Review of Literature

BACKGROUND

Pharyngoesophageal injury during anterior cervical spine surgery is a rare and potentially life-threatening complication; generally it is the result of intraoperative manipulation or hardware erosion and sometimes may be due to weakness of the pharyngoesophageal wall from pre-existing pathologic conditions, such as diabetes, gastritis, or obesity.

CASE DESCRIPTION

We describe the management strategies in patients with an early postoperative hypopharyngeal perforation that occurred after anterior cervical spine surgery without failure of instrumentation, and we present a case treated endoscopically at our institution.

CONCLUSIONS

Appropriate treatment for pharyngoesophageal perforations is controversial and not investigated in detail. There is a lack of prospective studies comparing initial conservative versus surgical approaches to treatment. In addition, endoscopic management is growing as a therapeutic option, but no consensus concerning the indications for an endoscopic approach in the treatment of pharyngoesophageal injury in anterior cervical spine surgery is currently reached. A common theme proposed in the literature is that early recognition and aggressive investigation and treatment are essential to ensure a good outcome. A customized interdisciplinary surgical approach is essential for successful treatment. Use of the transoral endoscopic approach is a useful noninvasive method to treat this rare but potentially devastating complication.

Assessing the Intraoperative Risk of Esophageal Perforation during Anterior Cervical Spine Surgery: A Study Using Intraoperative Computed Tomography

Introduction

Using intraoperative computed tomography (iCT), we aimed to clarify the course of the esophagus and pharynx during anterior cervical spine surgery to estimate the risk of intraoperative injury.

Methods

Sixteen patients who underwent anterior cervical spine surgery with intraoperative CT for registration of a navigation system without release of blade retraction were included. To investigate the status of the retracted esophagus and pharynx, the distance between the nasogastric tube and center of the vertebra (NVD) was measured at each disc and vertebral level (C4-7) using axial CT. The location of the cricoid cartilage, which may affect the shift of the esophagus and pharynx, was noted. Presence or absence of contact between the esophagus and the edge of the surgical blade was investigated.

Results

The NVDs were 28.0, 28.3, 28.9, 27.2, 24.7, 19.9, and 13.8 mm at C4, C4/5, C5, C5/6, C6, C6/7, and C7, respectively; NVDs at C6/7 or more caudal levels were significantly shorter than those at C6 or more cranial levels (P < 0.001). The cricoid cartilage was observed at the C4-C5/6 level. Esophageal contact with the edge of the blade was observed in nine cases at C6 or more caudal levels.

Conclusions

The esophagus, which was placed at C6 or more caudal levels, was directly retracted by the blade. Nevertheless, the pharynx, which was placed at C6 or more cranial levels, was mostly retracted with the cricoid cartilage. Thus, the risk of direct esophageal injury was higher at C6 or more caudal levels than at cranial levels.

Predictive Factors for Percutaneous Endoscopic Gastrostomy Tube Placement After Anterior Cervical Fusion

STUDY DESIGN

Retrospective case-control study.

OBJECTIVES

To identify incidence and risk factors for percutaneous endoscopic gastrostomy (PEG) tube placement after anterior cervical fusion (ACF).

METHODS

Adult patients undergoing elective ACF with/without corpectomy for spondylosis from 2002 to 2011 were identified using the Nationwide Inpatient Sample database. The primary outcome measure was PEG tube placement; secondary outcomes included in-hospital mortality, total hospital charges, and discharge disposition. Multiple regression analyses were conducted to identify independent predictors of PEG tube placement.

RESULTS

Of 164 097 patients, 217 (0.13%) required a PEG tube. Patients needing PEG tube placement were older (69 vs 52 years; P < .001) and more likely to be male (65% vs 46.6%; P < .001) when compared with control patients. After regression analysis, age over 65 year (odds ratio [OR] = 4.16; P < .001) was the strongest independent predictor for PEG tube placement; other associated factors included male gender (OR = 2.14; P < .001), congestive heart failure (OR = 4.11; P < .001), anemia (OR = 3.52; P < .001), alcohol abuse (OR = 2.80; P = .009), renal failure (OR = 2.25; P = .003), chronic lung disease (OR = 1.78; P < .001), corpectomy (OR = 2.16; P < .001), and fusion of ≥3 segments (OR = 1.74; P < .001). Mortality rate for patients requiring PEG tube placement was 5.1% versus 0.05% for controls (P < .001); average hospital charges were $134 379 versus $39 519 (P < .001), and nonroutine discharges were seen in 89.3% versus only 6.4% for controls (P < .001).

CONCLUSIONS

The incidence of PEG tube placement after ACF was 0.13% in this study. Identified risk factors included age >65, corpectomy, fusion of ≥3 segments, and various comorbidities. Additionally, there may be increased risk of in-hospital mortality, hospital charges, and nonroutine discharges among these patients.

Clinical Effects of Posterior Longitudinal Ligament Removal and Wide Anterior Cervical Corpectomy for Spondylosis

BACKGROUND

Removing the posterior longitudinal ligament in cervical corpectomy is a controversial issue. It is unclear whether the risks are counterbalanced by clinical benefits. Another unexplored topic is whether the width of the corpectomy affects outcome.

METHODS

This cross-sectional retrospective study included consecutive patients who underwent cervical corpectomy for spondylosis by 6 different neurosurgeons. We compared 2 groups, where the posterior longitudinal ligament was either removed (N = 15 patients) or preserved (N = 21 patients). The posterior width of the corpectomy was assessed postoperatively with computed tomography and magnetic resonance imaging. Clinical results were evaluated with the visual analog scale (VAS), Modified Japanese Orthopedic Association scale (MJOAS), Cooper scale, and neck disability index (NDI), in the long-term follow-up.

RESULTS

Compared to preservation, removal of the posterior longitudinal ligament produced more favorable clinical results (but not statistically significant), based on the VAS (+41%, P = 0.48), MJOAS (+26.5%, P = 0.62), Cooper scale (+19%, P = 0.75), and NDI (+62%, P = 0.22). Magnetic resonance imagings showed that removing the posterior longitudinal ligament produced greater evagination of the dural sac into the space left by the corpectomy. Improvements in clinical outcome were associated with more posterior bone wall removal in the corpectomy (corpectomy width ≥15.6 mm; P < 0.05), based on the VAS, NDI, and MJOAS.

CONCLUSIONS

Removing the posterior longitudinal ligament in cervical corpectomy may produce a better outcome, particularly when associated with more posterior bone wall removal in the corpectomy.

Successfull management of a cervical oesophageal injury after an anterior cervical approach: a case report

The anterior surgical approach for spinal repair, with or without the insertion of stabilizing hardware, is an established procedure in the management of anterior cervical spine (ACS) pathology. Esophageal injury during this approach is a rare complication that can be life threatening. No treatment protocol has yet been standardized. In addition to conservative measures, several surgical approaches have been presented, ranging from primary repair to reconstruction with local, regional, or distant flaps. The SCM muscle flap, used as reinforcement of a primary suture or as a patch to the lesion is in our opinion an effective treatment for persisting or recurring esophageal fistulae after anterior cervical spine surgery.

Prognostic Value of Lordosis Decrease in Radiographic Adjacent Segment Pathology After Anterior Cervical Corpectomy and Fusion

While cervical lordosis alteration is not uncommon after anterior cervical arthrodesis, its influence on radiological adjacent segment pathology (RASP) is still unclear. Biomechanical changes induced by arthrodesis may contribute to ASP onset. To investigate the correlation between cervical lordosis decrease and RASP onset after anterior cervical corpectomy and fusion (ACCF) and to determine its biomechanical effect on adjacent segments after surgery, 80 CSM patients treated with ACCF were retrospectively studied, and a baseline finite element model of the cervical spine as well as post-operation models with normal and decreased lordosis were established and validated. We found that post-operative lordosis decrease was prognostic in predicting RASP onset, with the hazard ratio of 0.45. In the FE models, ROM at the adjacent segment increased after surgery, and the increase was greater in the model with decreased lordosis. Thus, post-operative cervical lordosis change significantly correlated with RASP occurrence, and it may be of prognostic value. The biomechanical changes induced by lordosis change at the adjacent segments after corpectomy may be one of the mechanisms for this phenomenon. Restoring a well lordotic cervical spine after corpectomy may reduce RASP occurrence and be beneficial to long-term surgical outcomes.

Iatrogenic Vertebral Artery Injury During Anterior Cervical Spine Surgery: A Systematic Review

BACKGROUND

Iatrogenic vertebral artery injury (VAI) during anterior cervical surgery is rare but potentially catastrophic.

METHODS

Causes, presentation, diagnosis, management, prognosis, and prevention of VAI were reviewed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. English language studies and case reports published from 1980 to 2017 were retrieved. Data on diagnosis, surgical procedures and approach, site and cause of VAI, management, outcomes, and vertebral artery (VA) status were extracted.

RESULTS

In 25 articles including 54 patients, VAI was diagnosed during or after surgery commonly indicated for cervical degenerative diseases (64%), tumors (14%), and trauma (9%). The incidence of VAI for each side was similar regardless of approach. Common presentations were unexpected copious surgical bleeding, delayed hemorrhage of pseudoaneurysm with neck swelling, dyspnea, hypotension, and cervical bruits caused by arteriovenous fistula. Causes included drilling (61%), instrumentation (16%), and soft tissue retraction (8%). Direct exposure or angiography confirmed VAI. Ten patients had VA anomalies; collateral status was verified in 9 before definitive treatment. Tamponade was adopted for urgent hemostasis in most cases but with a high incidence of pseudoaneurysm (48%). Unknown VA status increased occlusion risk and neurologic sequelae (41%). VA repair and stent placement had excellent outcomes.

CONCLUSIONS

Extensive lateral decompression, loss of landmarks, and anatomic variations or pathologic status of VA increased VAI risk. Evaluation of collateral vessels before definitive treatment helped determine appropriate management and avoid neurologic sequelae. Tamponade was not recommended as definitive treatment. Meticulous preoperative evaluation, cautious intraoperative manipulation, and real-time radiographic guidance reduced VAI risk.

Microscope Enhanced the Efficacy and Safety of Anterior Cervical Surgery for Managing Cervical Ossification of the Posterior Longitudinal Ligament

Background

We aimed to compare microscope-assisted anterior cervical surgery with traditional open-base surgery for treating cervical ossification of the posterior longitudinal ligament (OPLL).

Material/Methods

Patients were grouped into microscope-assisted anterior cervical surgery group (case group, n=30) and conventional anterior cervical surgery group (control group, n=30). Baseline characteristics, intraoperative and post-operative indexes including operation time, blood loss amount, duration of hospitalization, visual analogue scale (VAS), and complication rate were recorded. The neurological functions of patients were assessed using the Japanese Orthopaedic Association (JOA) score. Furthermore, the corresponding rate of improved JOA score (RIS) in each group was also calculated to evaluate surgery outcomes.

Results

The average blood loss amount and hospital stay duration in the case group were lower than in the control group (p<0.05). The post-operative VAS scores of both groups were decreased significantly. Particularly the post-operative VAS score in the case group was significantly lower than that in the control group (p<0.05). While the improvement rate of JOA scores in the case group was significantly higher than that in control group after cervical spine surgery. A significantly higher RIS rate was observed in the case group (p<0.05). Furthermore, post-operative complications of patients in the case group were lower than those in the control group (p<0.05).

Conclusions

Compared to conventional anterior cervical surgery, surgeries operated with microscope exhibit higher efficacy and safety including less bleeding amount, shorter operation time, released pain degree, improved neurological functions, and fewer incidences of complications.

Titanium cages versus autogenous iliac crest bone grafts in anterior cervical discectomy and fusion treatment of patients with cervical degenerative diseases: a systematic review and meta-analysis

OBJECTIVE

A systematic review and partial meta-analysis is conducted to compare the efficacy and safety of anterior cervical decompression and fusion procedures employing either rectangular titanium cages or iliac crest autografts in patients suffering from cervical degenerative disc diseases.

METHODS

Medline, PubMed, CENTRAL, and Google Scholar databases were searched up to June 2015, using the key words cervical discectomy; bone transplantation; titanium cages; and iliac crest autografts. Outcomes of interbody fusion rates were compared using odds ratios (ORs) with 95% confidence intervals (CIs). Values of the Japanese Orthopaedic Association score, and visual analog scale before and after operation were also compared.

RESULTS

The rate of interbody fusion was similar between patients in the iliac crest autograft and titanium cage groups (pooled OR = 0.33, 95% CI = 0.07 to 1.66, P = .178). The overall analysis showed that patients in the two groups did not have significantly different post-surgery Japanese Orthopaedic Association score (pooled difference in means = -0.05, 95% CI = 0.73 to 0.63, P = .876). Improvement in arm and neck pain scores were assessed with a visual analog scale and differed significantly between patients in the iliac crest autograft and titanium cage groups (pooled difference in means = 0.16, 95% CI = -0.44 to 0.76, P = .610; and pooled difference in means = -0.44, 95% CI = -2.23 to 1.36, P = .634, respectively).

CONCLUSIONS

Our results suggest that the use of titanium cages constitutes a safe and efficient alternative to iliac crest bone autografts for anterior cervical discectomy with fusion.

Esophageal Perforation Following Anterior Cervical Spine Surgery: Case Report and Review of the Literature

STUDY DESIGN

Multicenter retrospective case series and review of the literature.

OBJECTIVE

To determine the rate of esophageal perforations following anterior cervical spine surgery.

METHODS

As part of an AOSpine series on rare complications, a retrospective cohort study was conducted among 21 high-volume surgical centers to identify esophageal perforations following anterior cervical spine surgery. Staff at each center abstracted data from patients' charts and created case report forms for each event identified. Case report forms were then sent to the AOSpine North America Clinical Research Network Methodological Core for data processing and analysis.

RESULTS

The records of 9591 patients who underwent anterior cervical spine surgery were reviewed. Two (0.02%) were found to have esophageal perforations following anterior cervical spine surgery. Both cases were detected and treated in the acute postoperative period. One patient was successfully treated with primary repair and debridement. One patient underwent multiple debridement attempts and expired.

CONCLUSIONS

Esophageal perforation following anterior cervical spine surgery is a relatively rare occurrence. Prompt recognition and treatment of these injuries is critical to minimizing morbidity and mortality.

Biomechanics of Cervical "Skip" Corpectomy Versus Standard Multilevel Corpectomy

STUDY DESIGN

In vitro biomechanical study of flexibility with finite-element simulation to estimate screw stresses.

OBJECTIVE

To compare cervical spinal stability after a standard plated 3-level corpectomy with stability after a plated 3-level "skip" corpectomy where the middle vertebra is left intact (ie, two 1-level corpectomies), and to quantify pullout forces acting on the screws during various loading modes.

SUMMARY OF BACKGROUND DATA

Clinically, 3-level cervical plated corpectomy has a high rate of failure, partially because only 4 contact points affix the plate to the upper and lower intact vertebrae. Leaving the intermediate vertebral body intact for additional fixation points may overcome this problem while still allowing dural sac decompression.

METHODS

Quasistatic nonconstraining torque (maximum 1 N m) induced flexion, extension, lateral bending, and axial rotation while angular motion was recorded stereophotogrammetrically. Specimens were tested intact and after corpectomy with standard plated and strut-grafted 3-level corpectomy (7 specimens) or "skip" corpectomy (7 specimens). Screw stresses were quantified using a validated finite-element model of C3-C7 mimicking experimentally tested groups. Skip corpectomy with C5 screws omitted was also simulated.

RESULTS

Plated skip corpectomy tended to be more stable than plated standard corpectomy, but the difference was not significant. Compared with standard plated corpectomy, plated skip corpectomy reduced peak screw pullout force during axial rotation (mode of loading of highest peak force) by 15% (4-screw attachment) and 19% (6-screw attachment).

CONCLUSIONS

Skip corpectomy is a good alternative to standard 3-level corpectomy to improve stability, especially during lateral bending. Under pure moment loading, the screws of a cervical multilevel plate experience the highest pullout forces during axial rotation. Thus, limiting this movement in patients undergoing plated multilevel corpectomy may be reasonable, especially until solid fusion is achieved.

Utility of the clivo-axial angle in assessing brainstem deformity: pilot study and literature review

There is growing recognition of the kyphotic clivo-axial angle (CXA) as an index of risk of brainstem deformity and craniocervical instability. This review of literature and prospective pilot study is the first to address the potential correlation between correction of the pathological CXA and postoperative clinical outcome. The CXA is a useful sentinel to alert the radiologist and surgeon to the possibility of brainstem deformity or instability. Ten adult subjects with ventral brainstem compression, radiographically manifest as a kyphotic CXA, underwent correction of deformity (normalization of the CXA) prior to fusion and occipito-cervical stabilization. The subjects were assessed preoperatively and at one, three, six, and twelve months after surgery, using established clinical metrics: the visual analog pain scale (VAS), American Spinal InjuryAssociation Impairment Scale (ASIA), Oswestry Neck Disability Index, SF 36, and Karnofsky Index. Parametric and non-parametric statistical tests were performed to correlate clinical outcome with CXA. No major complications were observed. Two patients showed pedicle screws adjacent to but not deforming the vertebral artery on post-operative CT scan. All clinical metrics showed statistically significant improvement. Mean CXA was normalized from 135.8° to 163.7°. Correction of abnormal CXA correlated with statistically significant clinical improvement in this cohort of patients. The study supports the thesis that the CXA maybe an important metric for predicting the risk of brainstem and upper spinal cord deformation. Further study is feasible and warranted.

Biomechanical testing of circumferential instrumentation after cervical multilevel corpectomy

STUDY DESIGN

Biomechanical investigation.

PURPOSE

This study describes ex vivo evaluation of the range of motion (ROM) to characterize the stability and need for additional dorsal fixation after cervical single-level, two-level or multilevel corpectomy (CE) to elucidate biomechanical differences between anterior-only and supplemental dorsal instrumentation.

METHODS

Twelve human cervical cadaveric spines were loaded in a spine tester with pure moments of 1.5 Nm in lateral bending (LB), flexion/extension (FE), and axial rotation (AR), followed by two cyclic loading periods for three-level corpectomies. After each cyclic loading session, flexibility tests were performed for anterior-only instrumentation (group_1, six specimens) and circumferential instrumentation (group_2, six specimens).

RESULTS

The flexibility tests for all circumferential instrumentations showed a significant decrease in ROM in comparison with the intact state and anterior-only instrumentations. In comparison with the intact state, supplemental dorsal instrumentation after three-level CE reduced the ROM to 12% (±10%), 9% (±12%), and 22% (±18%) in LB, FE, and AR, respectively. The anterior-only construct outperformed the intact state only in FE, with a significant ROM reduction to 57% (±35 %), 60% (±27%), and 62% (±35%) for one-, two- and three-level CE, respectively.

CONCLUSIONS

The supplemental dorsal instrumentation provided significantly more stability than the anterior-only instrumentation regardless of the number of levels resected and the direction of motion. After cyclic loading, the absolute differences in stability between the two instrumentations remained significant while both instrumentations showed a comparable increase of ROM after cyclic loading. The large difference in the absolute ROM of anterior-only compared to circumferential instrumentations supports a dorsal support in case of three-level approaches.

Comparison of two reconstructive techniques in the surgical management of four-level cervical spondylotic myelopathy

To compare the clinical efficacy and radiological outcome of treating 4-level cervical spondylotic myelopathy (CSM) with either anterior cervical discectomy and fusion (ACDF) or “skip” corpectomy and fusion, 48 patients with 4-level CSM who had undergone ACDF or SCF at our hospital were analyzed retrospectively between January 2008 and June 2011. Twenty-seven patients received ACDF (Group A) and 21 patients received SCF. Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI) score, and Cobb's angles of the fused segments and C2-7 segments were compared in the two groups. The minimum patient follow-up was 2 years. No significant differences between the groups were found in demographic and baseline disease characteristics, duration of surgery, or follow-up time. Our study demonstrates that there was no significant difference in the clinical efficacy of ACDF and SCF, but ACDF involves less intraoperative blood loss, better cervical spine alignment, and fewer postoperative complications than SCF.

[Cervical spondylotic myelopathy: clinical and radiological outcome of surgery on a series of 135 patients who underwent at neurosurgery department of CHU Avicenna]

La myélopathie cervicarthrosique est un syndrome clinique en relation avec la diminution des dimensions du canal rachidien, la cervicarthrose est l’étiologie principale après 50 ans. L'objectif du traitement est de rétablir les dimensions du canal rachidien cervical. Le choix de la technique chirurgicale sera guidé par l'analyse des signes cliniques, imageries, pré opératoire en fonction de laquelle sera pratiquée soit la voie antérieure, postérieure, ou exceptionnellement la voie combinée. Notre étude a pour but dans un premier temps d’évaluer à long terme les résultats cliniques et radiologiques de la chirurgie ensuite répondre à cette préoccupation: La lordose cervicale pré opératoire et postopératoire sont t-elles des facteurs de bon pronostic? Nous rapportons une étude rétrospective entre 2000 et 2013 portant sur 135 patients opérés dans notre formation et remplissant les critères inclusions. La collecte des données s'est faite en s'aidant du dossier médical des patients (échelle d'Association des orthopédistes Japonais), Imagerie (Radio, TDM, IRM), mesure de l'angle de courbure rachidienne en pré et postopératoire, ceci dans le but d’évaluer à long terme les résultats clinique et radiologique de la chirurgie. Ont été inclus dans notre étude 135 patients, 82 Hommes (60%), 53 femmes (40%) avec un âge moyen de 52 ans, ayant consulté pour des motifs divers (Névralgies cervicobrachiales, lourdeur des membres, troubles génito-sphinctériens). Soixante cinq patients (48%) ont bénéficié d'un abord antérieur (dissectomie, cloward, somatotomie médiane), 64 patients (47%) ont été opérés par voie postérieure (laminectomie de 1 à 3 niveaux) et 6 patients (5%) ont bénéficié d'un abord combiné dans un délai moyen de 3 mois devant la persistance des symptômes. Le niveau cervical le plus touché était C5C6 suivie de C4C5. L’évolution globale de nos patients était favorable dans 58% des cas, stationnaire dans 41% des cas et 1% d'aggravation. Soixante patients ayant présentés une amélioration en postopératoire avaient une courbure rachidienne en lordose, contre 17 patients en raideur et aucun patient en cyphose (p < 0.05). En définitive, la myélopathie est une pathologie fréquente dans la pratique neurochirurgicale, le diagnostic s'est beaucoup amélioré grâce à l'avènement de IRM, plusieurs voies d'abords sont utilisées en fonction des données cliniques et d'imageries, l’évolution reste favorable si la prise en charge est précoce avant l'apparition des déformations importantes de l'alignement sagittal du rachis.

Pharyngoesophageal diverticulum perforation 18 years after anterior cervical fixation

Anterior cervical spinal surgery can lead to various complications. We hereby present a case of two rare complications combined-pharyngo-oesophageal diverticulum and its perforation after cervical plate dislodgement. A 53-year old male patient presented with progressive dysphagia 18 years after anterior cervical spinal fusion with tricortical bone graft and custom-made plate at the C6/7 level. Oesophagography revealed a pharyngo-oesophageal diverticulum in front of the cervical plate. It was confirmed by subsequent oesophagoscopy, which also demonstrated a 3-cm longitudinal defect at the posterior wall of the diverticulum. During surgical exploration of the patient's neck, the plate was removed, the diverticulum was completely mobilized and excised, the oesophageal wall manually sutured and a cricopharyngeal myotomy performed. An oesophageal suture line failure was suspected postoperatively, but was not confirmed during reoperation. A year later, the patient has no dysphagia or any other symptoms.

Postoperative pharyngocutaneous fistula: treated by sternocleidomastoid flap repair and cricopharyngeus myotomy

INTRODUCTION

Pharyngoesophagocutaneous fistula (PEF) is one of the rare but serious complications of antero-lateral approach to cervical spine surgery. Because of its rarity, the true incidence of PEF is not clear. But, retrospective analysis of large series of cervical spine surgery reports 0-1.62 % incidence (Cloward in Surg 69:175-182, 1971; Elerkay et al. in J Neurosurg Spine 90(Suppl 1):35-41, 1999). Proximity to the vertebral column and thin walls makes the upper digestive tract vulnerable to injury in cervical trauma, surgical or nonsurgical. Presentation in early postoperative period is not rare and carries high morbidity and mortality (Jones and Ginsberg in Ann Thorac Surg 53(3):534-543, 1992). Various procedures for these fistulae such as simple closure, muscle flap interposition, esophageal diversion and jejunal interposition are reported. Some authors also advise removal of prosthetic plates and posterior stabilization, besides the repair of fistulae in a staged manner (Orlando et al. in Spine 28(15):E290-E295, 2003).

METHODS

Two similar cases of pharyngeal fistulae with similar etiology and clinical scenario are presented here, which were managed successfully with initial control of sepsis followed by delayed definitive repair with sternocleidomastoid muscle flap interposition and cricopharyngeus myotomy without removal of prosthetic plates.

RESULTS

Postoperatively, both patients showed no evidence of any wound complications or collections until the seventh day. A contrast swallow study on seventh day showed no leak following which soft diet was started. Both patients were not having any difficulty in swallowing or aspiration. On 1-year follow-up, both patients were having no difficulty in swallowing, no episodes of aspiration and no recurrence of fistula.

CONCLUSION

This case series highlights the importance of cricopharyngeus myotomy for treating PEF and the improved results with the prosthesis kept undisturbed.

Esophagus perforation complicating anterior cervical spine surgery

PURPOSE

To study the diagnosis and treatment strategy of esophagus perforation complicating anterior cervical spine surgery.

METHODS

From 2000 to 2010, we performed 1,045 cases of anterior cervical surgeries. One developed esophagus perforation. The diagnosis and treatment strategy of this case and the other five patients with esophagus perforation from other hospitals were retrospectively reviewed. For an intraoperative perforation, primary double layer suture was performed. Postoperatively, the patient took nutrition by a nasogastric tube instead of oral intake for one week. For three cases of perforations early in the post-operative period, oral intake was forbidden and nasogastric tube was conducted for nutrition support. The wound was debrided and open drainage was conducted postoperatively. Intravenous broad-spectrum antibiotic therapy was utilized. For perforations at postoperative year 3 and 7, prohibition of oral intake, intravenous broad-spectrum antibiotics therapy, and nasogastric tube nutrition support were all conducted and surgical debridement was performed. In operation, fixation plates and screws were removed, and the edges of the perforation were loosely approximated by synthetic absorbable sutures. Postoperatively, skin wound was kept open for drainage.

RESULTS

All the perforations healed evenly without secondary complications.

CONCLUSIONS

When a perforation is suspected, imaging techniques should be employed. Surgical treatment facilitates the healing of esophagus perforation. Supportive treatments including prohibition of oral intake, intravenous broad-spectrum antibiotic therapy, feeding with a nasogastric tube were mandatory parts of treatments.

What is the incidence and severity of dysphagia after anterior cervical surgery?

BACKGROUND

Existing studies suggest a relatively high incidence of dysphagia after anterior cervical decompression and fusion (ACDF). The majority of these studies, however, are retrospective in nature and lack a control group.

QUESTIONS/PURPOSES

We therefore (1) prospectively determined the incidence and severity of dysphagia after ACDF using lumbar decompression patients as a control group; and (2) determined which factors, if any, are associated with increased postoperative dysphagia.

METHODS

Patients undergoing either one- or two-level ACDF (n=38) or posterior lumbar decompression (n=56) were prospectively followed. Baseline patient characteristics were recorded. A dysphagia questionnaire was administered preoperatively and during the 2-week, 6-week, and 12-week postoperative visits. We found no differences in patient age, body mass index, or the preoperative incidence and severity of dysphagia between the cervical and lumbar groups. We compared the incidence and severity of dysphagia between the patients who had cervical and lumbar surgery.

RESULTS

Postoperatively, 71% of patients having cervical spine surgery reported dysphagia at 2 weeks followup. This incidence decreased to 8% at 12 weeks followup. The incidence and severity of dysphagia were greater in the cervical group at 2 and 6 weeks followup with a trend toward greater dysphagia at 12 weeks followup. Body mass index, gender, location of surgery, and the number of surgical levels were not related to the risk of developing dysphagia. We observed a correlation between operative time and the severity of postoperative dysphagia.

CONCLUSIONS

Dysphagia is common after ACDF. The incidence and severity of postoperative dysphagia decreases over time, although symptoms may persist at least 12 weeks after surgery.

LEVEL OF EVIDENCE

Level II, prospective, comparative study. See Guidelines for Authors for a complete description of levels of evidence.

Hypopharyngeal Wall Exposure within the Surgical Field : The Role of Axial Rotation of the Thyroid Cartilage during Anterior Cervical Surgery

OBJECTIVE

Esophageal/hypopharyngeal injury can be a disastrous complication of anterior cervical surgery. The amount of hypopharyngeal wall exposure within the surgical field has not been studied. The objective of this study is to evaluate the chance of hypopharyngeal wall exposure by measuring the amount of axial rotation of the thyroid cartilage (ARTC) and posterior projection of the hypopharynx (PPH).

METHODS

The study was prospectively designed using intraoperative ultrasonography. We measured the amount of ARTC in 27 cases. The amount of posterior projection of the hypopharynx (PPH) also was measured on pre-operative CT and compared at three different levels; the superior border of the thyroid cartilage (SBTC), cricoarytenoid joint and tip of inferior horn of the thyroid cartilage (TIHTC). The presence of air density was also checked on the same levels.

RESULTS

The angle of ARTC ranged from -6.9° to 29.7°, with no statistical difference between the upper and lower cervical group. The amount of PPH was increased caudally. Air densities were observed in 26 cases at the SBTC, but none at the TIHTC.

CONCLUSION

Within the confines of the thyroid cartilage, surgeons are required to pay more attention to the status of hypopharynx/esophagus near the inferior horn of the thyroid cartilage. The hypopharynx/esophagus at the TIHTC is more likely to be exposed than at the upper and middle part of the thyroid cartilage, which may increase the risk of injury by pressure. Surgeons should be aware of the fact that the visceral component at C6-T1 surgeries also rotates as much as when the thyroid cartilage is engaged with a retractor. The esophagus at lower cervical levels warrants more careful retraction because it is not protected by the thyroid cartilage.

Deformative stress associated with an abnormal clivo-axial angle: A finite element analysis

Background:

Chiari malformation, functional cranial settling and subtle forms of basilar invagination result in biomechanical neuraxial stress, manifested by bulbar symptoms, myelopathy and headache or neck pain. Finite element analysis is a means of predicting stress due to load, deformity and strain. The authors postulate linkage between finite element analysis (FEA)-predicted biomechanical neuraxial stress and metrics of neurological function.

Methods:

A prospective, Internal Review Board (IRB)-approved study examined a cohort of 5 children with Chiari I malformation or basilar invagination. Standardized outcome metrics were used. Patients underwent suboccipital decompression where indicated, open reduction of the abnormal clivo-axial angle or basilar invagination to correct ventral brainstem deformity, and stabilization/ fusion. FEA predictions of neuraxial preoperative and postoperative stress were correlated with clinical metrics.

Results:

Mean follow-up was 32 months (range, 7-64). There were no operative complications. Paired t tests/ Wilcoxon signed-rank tests comparing preoperative and postoperative status were statistically significant for pain, bulbar symptoms, quality of life, function but not sensorimotor status. Clinical improvement paralleled reduction in predicted biomechanical neuraxial stress within the corticospinal tract, dorsal columns and nucleus solitarius.

Conclusion:

The results are concurrent with others, that normalization of the clivo-axial angle, fusion-stabilization is associated with clinical improvement. FEA computations are consistent with the notion that reduction of deformative stress results in clinical improvement. This pilot study supports further investigation in the relationship between biomechanical stress and central nervous system (CNS) function.

Diagnosing cervical fusion: a comprehensive literature review

Study Design

Comprehensive literature review.

Purpose

To document the criteria for fusion utilized in these studies to determine if a consensus on the definition of a solid fusion exists.

Overview of Literature

Numerous studies have reported on fusion rates following anterior cervical arthrodesis. There is a wide discrepancy in the fusion rates in these studies. While factors such as graft type, Instrumentation, and technique play a factor in fusion rate, another reason for the difference may be a result of differences in the definition of fusion following anterior cervical spine surgery.

Methods

A comprehensive English Medline literature review from 1966 to 2004 using the key words "anterior," "cervical," and "fusion" was performed. We divided these into two groups: newer studies done between 2000 and 2004, and earlier studies done between 1966 and 2000. These articles were then analyzed for the number of patients, follow-up period, graft type, and levels fused. Moreover, all of the articles were examined for their definition of fusion along with their fusion rate.

Results

In the earlier studies from 1966 to 2000, there was no consensus for what constituted a solid fusion. Only fifteen percent of these studies employed the most stringent definition of a solid fusion which was the presence of bridging bone and the absence of motion on flexion and extension radiographs. On the other hand, the later studies (2000 to 2004) used such a definition a majority (63%) of the time, suggesting that a consensus opinion for the definition of fusion is beginning to form.

Conclusions

Our study suggests that over the past several years, a consensus definition of fusion is beginning to form. However, a large percentage of studies are still being published without using stringent fusion criteria. To that end, we recommend that all studies reporting on fusion rates use the most stringent criteria for solid fusion following anterior cervical spine surgery: the absence of motion on flexion/extension views and presence of bridging trabeculae on lateral x-rays. We believe that a universal adoption of such uniform criteria will help to standardize such studies and make it more possible to compare one study with another.

Cervical anterior transpedicular screw fixation. Part I: Study on morphological feasibility, indications, and technical prerequisites

Multilevel cervical spine procedures can challenge the stability of current anterior cervical screw-and-plate systems, particularly in cases of severe three-column subaxial cervical spine injuries and multilevel plated reconstructions in osteoporotic bone. Supplemental posterior instrumentation is therefore recommended to increase primary construct rigidity and diminish early failure rates. The increasing number of successfully performed posterior cervical pedicle screw fixations have enabled more stable fixations, however most cervical pathologies are located anteriorly and preferably addressed by an anterior approach. To combine the advantages of the anterior approach with the superior biomechanical characteristics of cervical pedicle screw fixation, the authors developed a new concept of a cervical anterior transpedicular screw-and-plate system. An in vivo anatomical study was performed to explore the feasibility of anterior transpedicular screw fixation (ATPS) in the cervical spine. The morphological study was conducted based on 29 cervical spine CT scans from healthy patients and measurements were performed on the pedicle sizes, angulations, vertebral body depth, height and width at C2 to T1. Significant morphologic parameters for the new technique are discussed. These parameters include the sagittal and transverse intersection points of the pedicle axis with the anterior vertebral body wall, as well as the distances between sagittal intersection points from C2 to T1. On the basis of these results, standard spine models were reconstructed and used for the conceptual development of a preclinical release prototype of an anterior transpedicular screw-and-plate system. The morphological feasibility of the new technique is demonstrated, and its indications, biomechanical considerations, as well as surgical prerequisites are thoroughly discussed. In the future, the technique of cervical anterior transpedicular screw fixation might diminish the number of failures in the reconstruction of multilevel and three-column cervical spine instabilities, and avoid the need for supplemental posterior instrumentation.

Anterior cervical corpectomy and fusion accelerates degenerative disease at adjacent vertebral segments

BACKGROUND

Anterior cervical corpectomy provides the most direct and thorough surgical approach for anterior decompression when spinal cord compression is found directly behind the vertebral body. However, anterior cervical fusion has been shown to be associated with the development of new degenerative changes at levels immediately adjacent to the fused segments. Th e incidence of adjacent segment disease (ASD) following anterior cervical corpectomy has not been widely reported. We set out to determine the incidence of clinical ASD following anterior cervical corpectomy.

METHODS

We retrospectively reviewed all available medical charts and radiographic studies of all cases of anterior cervical corpectomy performed at the Barrow Neurological Institute over a 4-year period with a minimum 24-month follow-up. Factors assessed included the success of arthrodesis, the presence of degenerative changes on serial follow-up radiographs, and the development of new neurological symptoms.

RESULTS

Seventy-six patients met the criteria for inclusion: 54 had undergone a 1-level corpectomy, 18 underwent a 2-level corpectomy, and 4 underwent a 3- or 4-level corpectomy. Arthrodesis was performed with either allograft or autograft and anterior cervical plating. All patients achieved successful fusion. Follow-up was available for a minimum of 2 years in all cases, with a mean length of 3.6 years. Sixteen patients (21%) eventually developed radiological and clinical evidence of degenerative changes at adjacent levels. In 10 of 11 patients who developed clinical symptoms within 2 years, the changes represented progression of pre-existing, asymptomatic degenerative disease. Five patients developed degenerative changes more than 5 years after surgery; these were all associated with an unrelated new insult to the cervical spine such as trauma.

CONCLUSIONS

Anterior cervical corpectomy with fixation can accelerate degenerative changes identified preoperatively at adjacent, asymptomatic levels of the cervical spine.

LEVEL OF EVIDENCE

Retrospective cohort study (level 2b).

Transient long segment spinal cord hyperintensity after anterior cervical discectomy

A 69-year-old man was admitted to our hospital with progressive numbness in both feet and gait disturbance. MR imaging revealed a large cervical disc herniation resulting in significant spinal cord compression with hyperintensity of the spinal cord on T2-weighted images at C-5/6. Immediately after undergoing anterior cervical discectomy, the patient developed severe weakness of his left hand and lower extremities. MR imaging obtained 5 days after surgery revealed a long segment hyperintensity between C-3 and T-2 on T2-weighted images. This long segment hyperintensity disappeared after 2 weeks of steroid administration. We suspect that the persistent, localised, patchy C-5/6 cord hyperintensity represents spinal cord degeneration due to ischaemia and trauma resulting from the disc herniation. However, the transient long segment hyperintensity may represent oedema, probably due to minor trauma of an already compromised cord, during the decompression surgery. Clinicians should be aware that even careful surgery can result in a significant change in radiological studies and neurological condition.

4- and 5-level anterior fusions of the cervical spine: review of literature and clinical results

In the future, there will be an increased number of cervical revision surgeries, including 4- and more-levels. But, there is a paucity of literature concerning the geometrical and clinical outcome in these challenging reconstructions. To contribute to current knowledge, we want to share our experience with 4- and 5-level anterior cervical fusions in 26 cases in sight of a critical review of literature. At index procedure, almost 50% of our patients had previous cervical surgeries performed. Besides failed prior surgeries, indications included degenerative multilevel instability and spondylotic myelopathy with cervical kyphosis. An average of 4.1 levels was instrumented and fused using constrained (26.9%) and non-constrained (73.1%) screw-plate systems. At all, four patients had 3-level corpectomies, and three had additional posterior stabilization and fusion. Mean age of patients at index procedure was 54 years with a mean follow-up intervall of 30.9 months. Preoperative lordosis C2-7 was 6.5 degrees in average, which measured a mean of 15.6 degrees at last follow-up. Postoperative lordosis at fusion block was 14.4 degrees in average, and 13.6 degrees at last follow-up. In 34.6% of patients some kind of postoperative change in construct geometry was observed, but without any catastrophic construct failure. There were two delayed unions, but finally union rate was 100% without any need for the Halo device. Eleven patients (42.3%) showed an excellent outcome, twelve good (46.2%), one fair (3.8%), and two poor (7.7%). The study demonstrated that anterior-only instrumentations following segmental decompressions or use of the hybrid technique with discontinuous corpectomies can avoid the need for posterior supplemental surgery in 4- and 5-level surgeries. However, also the review of literature shows that decreased construct rigidity following more than 2-level corpectomies can demand 360 degrees instrumentation and fusion. Concerning construct rigidity and radiolographic course, constrained plates did better than non-constrained ones. The discussion of our results are accompanied by a detailed review of literature, shedding light on the biomechanical challenges in multilevel cervical procedures and suggests conclusions.

Esophageal injury associated with anterior cervical spine surgery

BACKGROUND

Anterior cervical spinal surgery has been used to treat a variety of conditions including spondylosis, fracture, tumor, infection, trauma, and instability. Esophageal perforation, a rare and unusual complication of anterior cervical procedures, has been largely relegated to only incidental case reports with few large retrospective studies performed to determine true incidence, treatment, etiology, and outcome.

METHODS

More than 3000 anterior cervical spine surgeries conducted over a 30-year period by 5 active practicing surgeons were reviewed. There were 3 cases of esophageal injury identified with subsequent critical evaluation to determine presentation, diagnosis, risk factors, management, and outcomes. In addition, incidence rates were calculated based on overall occurrence and antecedent risk factors.

RESULTS

Two of the patients with esophageal injury had predisposing risk factors, including diverticula or cervical spine trauma. The third patient had no antecedent risk factors. Symptoms included axial spine pain, odynophagia, dysphagia, purulent spondylitis, and sepsis. Treatment consisted of one or more of the following: reoperation with exploration and repair, esophageal diversion, esophageal rest, antibiotic administration, and wound drainage. Functional outcomes were achieved in all cases with no deaths.

CONCLUSIONS

Esophageal injury incidence based on overall occurrence in this study was 0.1%. Patients with no antecedent risk factors had an incidence of 0.03%. Our results compare favorably with those of the Cervical Spine Research Society survey from 1989, which predicted an incidence of 0.25% based on questionnaires filed by surgeons, representing 1 of only 2 reports that included more than 1000 patients.

Multilevel cervical fusion without plates, screws or autogenous iliac crest bone graft

OBJECTIVE

This prospective study was performed to evaluate the safety and efficacy of polyetheretherketone (PEEK) cages packed with demineralized bone matrix (DBM) mixed with autologous blood and curettage microchip material for treatment of multilevel cervical disc disease and spondylosis without the use of plates, screws or autogenous iliac crest bone graft.

MATERIAL AND METHODS

Sixteen patients underwent multilevel anterior cervical discectomy and fusion (ACDF) for a total of 42 levels. Minimum follow-up was 18 months. Neurological outcomes were evaluated using the Japanese Orthopaedic Association (JOA) scoring system; cervical lordosis and cervical fusion status was assessed on X-ray. Statistical analysis was performed to compare preoperative and postoperative scores using a dependent t-test (P<0.05).

RESULTS

Eight patients underwent two-level, six underwent three-level and two underwent four-level operations. The fusion rate was 90.5% and non-fusion rate was 9.5%, but reoperation was not required for these patients in the follow-up period. Cervical lordosis was preserved and neurological status was improved. No cage migration or cage failure occured.

CONCLUSION

ACDF using PEEK cages packed with DBM is a safe and efficient method for treatment of multilevel cervical disc disease and spondylosis. It preserves cervical lordosis and obviates the complications related to iliac crest graft harvest and screw-plate fixation.

Successful treatment of cervical myelopathy with minimal morbidity by circumferential decompression and fusion

Circumferential cervical decompression and fusion (CCDF) is an important technique for treating patients with severe cervical myelopathy. While circumferential cervical decompression and fusion may provide improved spinal cord decompression and stability compared to unilateral techniques, it is commonly associated with increased morbidity and mortality. We performed a retrospective analysis of patients undergoing CCDF at the University of California, San Francisco (UCSF) between January 2003 and December 2004. We identified 53 patients and reviewed their medical records to determine the effectiveness of CCDF for improving myelopathy, pain, and neurological function. Degree of fusion, functional anatomic alignment, and stability were also assessed. Operative morbidity and mortality were measured. The most common causes of cervical myelopathy, instability, or deformity were degenerative disease (57%) and traumatic injury (34%). Approximately one-fifth of patients had a prior fusion performed elsewhere and presented with fusion failure or adjacent-level degeneration. Postoperatively, all patients had stable (22.6%) or improved (77.4%) Nurick grades. The average preoperative and postoperative Nurick grades were 2.1 +/- 1.9 and 0.4 +/- 0.9, respectively. Pain improved in 85% of patients. All patients had radiographic evidence of fusion at last follow-up. The most common complication was transient dysphagia. Our average clinical follow-up was 27.5 +/- 9.5 months. We present an extensive series of patients and demonstrate that cervical myelopathy can successfully be treated with CCDF with minimal operative morbidity. CCDF may provide more extensive decompression of the spinal cord and may be more structurally stable. Concerns regarding operation-associated morbidity should not strongly influence whether CCDF is performed.

Comparison of multisegment anterior cervical fixation using bone strut graft versus a titanium rod and buttress prosthesis: analysis of outcome with long-term follow-up and interview by independent physician

STUDY DESIGN

A retrospective study of 73 consecutive patients who underwent cervical corpectomy and anterior strut fixation over 3 or more disc levels between July 1989 and May 1999.

OBJECTIVE

To compare the efficacy of cervical spine fixation by autologous strut graft from iliac crest or fibula versus a titanium prosthesis without bone graft.

SUMMARY OF BACKGROUND DATA

Strut grafting after multilevel anterior cervical corpectomy remains a challenging procedure, with published dislocation rates from 0% to 71%, and nonunion from 0% to 54%. This paper describes a quicker and easier alternative to the use of a bone strut, imparting a very high degree of immediate spinal stability, and osseous integration equivalent to bone fusion.

METHODS

Thirty-eight bone-graft operations and 38 titanium prosthesis operations were performed on 73 patients between July 24, 1989 and May 20, 1999. Average follow-up was 53.2 months (range 19.8-134).

RESULTS

The group of patients who received the prosthesis was significantly older than the bone-grafted group and required significantly more segments excised, but operation times were significantly shorter than for the bone strut operation. The titanium prosthesis had a lower incidence of dislodgement in the early postoperative period (1/38 vs. 4/38 for bone struts) but a higher rate of late reoperation (4/38 vs. 1/38 for bone struts). The SF-36 scores in the domain of Physical Function (only) were significantly higher in the bone-grafted group (P = 0.016, Mann Whitney), consistent with the difference in mean ages of the 2 groups. The groups were indistinguishable by Odom criteria, patient verdict, pain scores, analgesic intake, length of hospital stay, radiologic fusion rate, and residual symptoms.

CONCLUSION

A titanium rod and buttress prosthesis may be a faster and easier alternative to conventional iliac crest/fibula autograft after multisegmental cervical vertebral corpectomy.

Indications for circumferential surgery for cervical spondylotic myelopathy

BACKGROUND CONTEXT

The surgical management of patients with cervical spondylotic myelopathy (CSM) remains challenging.

PURPOSE

To review the indications, techniques, and results of circumferential fusion for CSM.

CONCLUSION

Circumferential decompression and stabilization with instrumentation is a viable option to treat selected complex cervical spine disorders. It provides immediate stabilization of the spine, decreases anterior graft and instrumentation failure, and can obviate the need for postoperative halo immobilization.

Complications and Long-Term Follow-Up Results in Titanium Mesh Cage Reconstruction After Cervical Corpectomy

OBJECTIVE

The incidence of the complications and long-term outcome with a minimum 2-year follow-up of anterior cervical reconstruction using titanium mesh cage is evaluated. Relevant literature was also reviewed to discuss the potential risk factors of the complications of this procedure.

METHODS

From 1999 to 2003, 26 patients with cervical spine disorders, (12 patients with OPLL, 7 with cervical spondylosis, 3 with vertebral tumors, 2 with osteomyelitis, and 2 with traumatic lesions) were operated on by this procedure. The series included 14 males and 12 females with a mean age of 60.9 years. Corpectomy was performed on 1 (14 cases), 2 (12 cases). Autologous bone fragments were taken from the excised vertebra.

RESULTS

The average improvement rate as scored on the neurosurgical cervical spine scale was 67.4%. The average follow-up period was 54.3 months (range, 24 to 72 months) in 21 who were followed up, and bone union was observed in all cases (22/22 cases) that could be followed up for more than 6 months postoperatively. The average time required for fusion was 6.7 months. Postoperative complications included dyspnea (1 case) and cerebrospinal fluid leakage (2 cases), which was treated by lumbar drainage, without any additional repair operation. No hardware-related complications or adjacent segment degenerative changes were encountered during the follow-up periods.

CONCLUSIONS

This reconstruction technique yielded good clinical results and helped to avoid complications associated with harvesting bone from the iliac crest donor site. However, risk factors related to the method should be carefully considered.

The V2 segment of the vertebral artery in anterior and anterolateral cervical spinal surgery: A cadaver angiographic study

OBJECTIVE

The second segment of the vertebral artery is under the risk of injury during anterior and anterolateral cervical spine procedures. To avoid such a risk, one needs to be familiar with the regional anatomy. The aim of this study was to measure the distance between the vertebral artery and the uncinate process, midline, and the medial side of the longus colli muscle using vertebral artery angiograms at the level of C6, C5, C4, and C3 vertebrae.

MATERIALS AND METHODS

In 12 human cadavers, the vertebral arteries were first irrigated with water. Then the arteries were filled with silicon and barium, and finally their angiographic images were obtained.

RESULTS

The transverse diameter of the vertebral artery was measured at C6, C5, C4, C3, and C2 level. The values on the left were bigger than the values on the right (p>0.05). The distance between the vertebral artery and the midline decreased from C6 (17.2+/-5.6mm on the right, 17.2+/-2.3mm on the left) to C3 (15.8+/-5.3mm on the right, 13.8+/-2.1mm on the left) (p>0.05). The distance between the apex of the uncinate process and the medial side of the vertebral artery was found to be longer at C4 (2.7+/-1.0 mm on the right, 2.2+/-1.0mm on the left) and C5 (2.5+/-1.1mm on the right, 2.5+/-1.0mm on the left) vertebra levels on the right side (p=0.339 at C4, p=0.862 at C5). The distance between the medial side of the longus colli muscle and the medial side of the vertebral artery was measured as 9.7+/-2.7 mm (9.5+/-2.9 mm on the right, 9.8+/-2.6mm on the left) at C6 level, 9.2+/-2.6mm (8.6+/-2.4mm on the right, 9.8+/-3.1mm on the left) at C5, 9.4+/-1.9 mm (9.2+/-2.1mm on the right, 9.5+/-2.0mm on the left) at C4, and 10.4+/-2.7 mm (10.5+/-3.0mm on the right, 10.1+/-2.6mm on the left) at C3 vertebra level. No significant difference was found between the right and the left (p>0.05). The angle between the vertebral artery and the midline was measured as 4.0+/-1.9 degrees on the right and 2.2+/-1.4 degrees on the left side (p=0.030).

CONCLUSION

It was considered that the values obtained could be useful in anterolateral and anterior cervical approaches in terms of evaluating the position of the vertebral artery and its relation to vertebral structures. It is also concluded that the risk of injury in upper subaxial cervical spine is higher than in the lower part of the subaxial cervical spine.

Functional outcome after central corpectomy in poor-grade patients with cervical spondylotic myelopathy or ossified posterior longitudinal ligament

OBJECTIVE

We studied the long-term functional outcome in poor-grade patients (Nurick Grades 4 and 5) with cervical spondylotic myelopathy (CSM) or ossified posterior longitudinal ligament after central corpectomy (CC). We sought to determine whether there were any prognostic factors that could predict functional outcome in these patients.

METHODS

Functional outcome data were collected for 72 patients (68 men and 4 women; mean age, 49.7 yr; range, 30-67 yr) with CSM (60 patients) or OPLL (12 patients) of Nurick Grades 4 (55 patients) and 5 (17 patients). Uninstrumented CC was performed at 1 level in 12 patients, at 1 level combined with a discoidectomy at another level in 4 patients, at 2 levels in 50 patients, and at 2 levels plus a discoidectomy in 5 patients. The age at presentation (< or =50 yr or >50 yr), grade before surgery (4 or 5), the number of levels operated (1 or >1), diagnosis (CSM or ossified posterior longitudinal ligament), and duration of myelopathic symptoms (< or =12 mo or >12 mo) were studied for their effect on the functional outcome noted at the last follow-up. Functional outcome was graded as poor (no change in Nurick grade), fair (improvement of one Nurick grade), good (improvement of two Nurick grades), and cure (follow-up Nurick grade of 0 or 1).

RESULTS

The follow-up ranged from 9 to 104 months (mean, 36.3 mo). One patient died 3 weeks after CC after surgery for a perforated duodenal ulcer. There was transient operative morbidity in 12 patients (16.9%). The mean Nurick score improved from 4.24 to 2.47 (P < 0.001). Of the 54 patients (76%) who improved in their Nurick grade, the functional outcome was graded as fair in 13 patients (18.3%), good in 24 patients (33.8%), and cure in 17 patients (23.9%). The functional outcome was poor in 17 patients (23.9%). Functional improvement after CC was uniformly correlated with myelopathic symptoms of 12 months' duration or shorter. The other favorable prognostic indicators for improvement after CC were a diagnosis of CSM and preoperative Nurick Grade 5; however, patients with a preoperative Nurick grade of 4 were more likely to experience a cure.

CONCLUSION

More than three-fourths of patients with poor-grade CSM improve in their functional status after CC, with nearly 24% of patients obtaining a cure. Because patients with a duration of myelopathic symptoms of 12 months or less had the best functional outcome, early decompressive surgery should be offered to patients with poor-grade CSM.

Osteoradionecrosis of the cervical spine resulting from radiotherapy for primary head and neck malignancies: operative and nonoperative management

✓ Osteoradionecrosis is a process of dysvascular bone necrosis and fibrous replacement following exposure to high doses of radiation. The poorly vascularized necrotic tissue may cause pain and/or instability, and it cannot resist infection well, which may result in secondary osteomyelitis. When these processes affect the cervical spine, the resulting instability and neurological deficits can be devastating, and immediate reestablishment of spinal stability is paramount. Reconstruction of the cervical spine can be particularly challenging in this subgroup of patients in whom the spine is poorly vascularized after radical surgery, high-dose irradiation, and infection. The authors report three cases of cervical spine osteoradionecrosis following radiotherapy for primary head and neck malignancies. Two patients suffered secondary osteomyelitis, severe spinal deformity, and spinal cord compression. These patients underwent surgery in which a vascularized fibular graft and instrumentation were used to reconstruct the cervical spine; subsequently hyperbaric oxygen (HBO) therapy was instituted. Fusion occurred, spinal stability was restored, and neurological dysfunction resolved at the 2- and 4-year follow-up examinations, respectively. The third patient experienced pain and dysphagia but did not have osteomyelitis, spinal instability, or neurological deficits. He underwent HBO therapy alone, with improved symptoms and imaging findings. Hyperbaric oxygen is an essential part of treatment for osteoradionecrosis and may be sufficient by itself for uncomplicated cases, but surgery is required for patients with spinal instability, spinal cord compression, and/or infection. A vascularized fibular bone graft is a very helpful adjunct in these patients because it adds little morbidity and may increase the rate of spinal fusion.

Effect of constrained posterior screw and rod systems for primary stability: biomechanical in vitro comparison of various instrumentations in a single-level corpectomy model

Cervical corpectomy is a frequently used technique for a wide variety of spinal disorders. The most commonly used approach is anterior, either with or without plating. The results for single-level corpectomy are better than in multilevel procedures. Nevertheless, hardware- or graft-related complications are observed. In the past, constrained implant systems were developed and showed encouraging stability, especially for posterior screw and rod systems in the lumbar spine. In the cervical spine, few reports about the primary stability of constrained systems exist. Therefore, in the present study we evaluated the primary stability of posterior screw and rod systems, constrained and non-constrained, in comparison with anterior plating and circumferential instrumentations in a non-destructive set-up, by loading six human cadaver cervical spines with pure moments in a spine tester. Range of motion and neutral zone were measured for lateral bending, flexion/extension and axial rotation. The testing sequence consisted of: (1) stable testing; (2) testing after destabilization and cage insertion; (3a) additional non-constrained screw and rod system with lateral mass screws, (3b) with pedicle screws instead of lateral mass screws; (4a) constrained screw and rod system with lateral mass screws, (4b) with pedicle screws instead of lateral mass screws; (5) 360 degrees set-up; (6) anterior plate. The stability of the anterior plate was comparable to that of the non-constrained system, except for lateral bending. The primary stability of the non-constrained system could be enhanced by the use of pedicle screws, in contrast to the constrained system, for which a higher primary stability was still found in axial rotation and flexion/extension. For the constrained system, the achievable higher stability could obviate the need to use pedicle screws in low instabilities. Another benefit could be fewer hardware-related complications, higher fusion rate, larger range of instabilities to be treated by one implant system, less restrictive postoperative treatment and possibly better clinical outcome. From a biomechanical standpoint, in regard to primary stability the constrained systems, therefore, seem to be beneficial. Whether this leads to differences in clinical outcome has to be evaluated in clinical trials.

Intraoperative evaluation of bone decompression in anterior cervical spine surgery by three-dimensional fluoroscopy

Sufficient bone decompression of osteophytes is essential for functional long-term outcome in surgery for spondylotic cervical myelopathy. Postoperative CT scans clearly show that decompression is sometimes insufficient. Intraoperative CT scanning has been used to monitor sufficient decompression. Instead of standard intraoperative fluoroscopy, we used an isocentered three-dimensional (3D) fluoroscopy with 3D image reconstruction to evaluate the extent of bone decompression. From October 2003 to April 2004, we have used intraoperative 3D fluoroscopy on seven patients with anterior cervical spine surgery due to cervical spondylotic myelopathy. Five patients were operated on in one level, two patients had surgery in two segments. If surgery was performed in two levels or preoperative cinetic MRT showed cervical instability, internal plate fixation was done additionally. All patients were positioned on a radiolucent operating table, made of carbon fibers. Three-dimensional fluoroscopy was always performed before wound closure to evaluate sufficient bone removal. The scanning time was 120 s and the whole procedure from scanning to evaluation is approximately 5 min. In all patients we were able to evaluate the extent of bone decompression. Additionally, placement of cage, plates and screws can be evaluated intraoperatively. In one patient, 3D fluoroscopy showed insufficient decompression, especially on the right side. Further bone removal was performed before the end of the procedure. Intraoperative 3D fluoroscopy is a valuable tool for imaging bone decompression and implant location in anterior cervical spine surgery. The technique is safe, reliable and should help us to avoid incomplete decompression or misplacement of implants and therefore improve long-term functional outcome in cervical spine surgery in the future.

Excision of high and mid cervical spinal cord arteriovenous malformations by anterior operation

Symptomatic cervical spinal arteriovenous malformations (AVMs) located on the anterior aspect of the spinal cord are rare and surgical removal of these AVMs presents considerable challenges and risks. Surgical techniques to date have usually been by posterior approach and lateral dissection around the cord or via midline myelotomy, both approaches involving cord manipulation and retraction and in the latter, dissection through the spinal cord. We present two teenage patients with symptomatic anteriorly placed mid to high cervical spinal AVMs and associated aneurysm in which excision of the AVMs and aneurysm was performed by an anterior approach using vertebrectomy/corpectomy. The first case had a small perimedullary glomus-type AVM with an aneurysm on the anterior aspect of the cord at the C3/4 level; excision was performed using a single level vertebrectomy/corpectomy, the patient remaining neurologically intact. The second case had a medium-sized juvenile AVM with an aneurysm, both perimedullary and intramedullary, centred at the C5/6 level; excision was performed using a two-level vertebrectomy/corpectomy with no deterioration in the marked pre-operative tetraparesis, which at long-term follow up had improved and stabilised. Anterior approaches have been recently described for treatment of anteriorly placed cervical arteriovenous fistulas (AVFs) and an intramedullary haemangioblastoma, but not as yet for spinal AVMs. These are the first two reported cases of anteriorly situated cervical AVMs successfully removed surgically by an anterior approach and with good neurological outcomes.