Five-year outcome of stand-alone fusion using carbon cages in cervical disc arthrosis

Assessing accuracy of measurement methods for bony fusion assessment after anterior cervical discectomy

BACKGROUND CONTEXT

Currently, there is no universally accepted method for assessing radiological fusion shortly after anterior cervical discectomy. Five-year follow-up radiological X-rays demonstrating solid fusion or absence of fusion provided a gold standard for comparison with various assessment methods.

PURPOSE

Establishing the most accurate diagnostic test for earlier bony fusion assessment by comparing different cut-off values for the difference in interspinous distance and the change in Cobb angle on dynamic radiological images against the established gold standard.

DESIGN

Posthoc analysis from the NEtherlands Cervical Kinematics (NECK) trial (NTR1289).

PATIENT SAMPLE

A total of 40 patients with 1 level herniated disc that underwent anterior discectomy between 2010 and 2014 returned for a 5-year follow-up X-ray.

OUTCOME MEASURES

Radiological outcome was assessed quantitatively and qualitatively by fusion on radiographic images 5 years after surgery.

METHODS

Radiological dynamic X-rays were reviewed for fusion at 5-year follow-up by a senior spine surgeon. At this timepoint, bony continuity was indisputable and served as gold standard. Cobb angles and interspinous distances on flexion-extension images were measured independently by 2 investigators. Optimum agreement between the gold standard and the 2 methods was assessed, evaluating varying cut-off values, considering sensitivity, specificity, and area under the curve (AUC).

RESULTS

Dynamic radiographic assessments revealed fusion in 29 out of 40 patients (mean age: 49 years ± 8; 23 women). For Cobb angle (optimal cut-off: ≤3.0°), the AUC was 0.86 with 100% sensitivity and 72.7% specificity. For interspinous distance (optimal cut-off: ≤1.5 mm), the AUC was 0.89 with 96.6% sensitivity and 81.8% specificity. The highest AUC (0.91) was observed for combined cut-off values (Cobb angle ≤3.0° and interspinous distance ≤2.0 mm), yielding 100% sensitivity and 81.8% specificity.

CONCLUSION

The combination of cut-off values ≤3.0° difference for Cobb angle and ≤2.0 mm difference for interspinous distance on lateral flexion-extension X-rays was assessed to be an accurate diagnostic criterion for fusion evaluation. This tool provides a practical and easy applicable method for assessing fusion during follow-up after anterior discectomy.

Evaluation of Topology Optimization Using 3D Printing for Bioresorbable Fusion Cages: A Biomechanical Study in a Porcine Model

STUDY DESIGN

Preclinical biomechanical study of topology optimization versus standard ring design for bioresorbable poly-ε-caprolactone (PCL) cervical spine fusion cages delivering bone morphogenetic protein-2 (BMP-2) using a porcine model.

OBJECTIVE

The aim was to evaluate range of motion (ROM) and bone fusion, as a function of topology optimization and BMP-2 delivery method.

SUMMARY OF BACKGROUND DATA

3D printing technology enables fabrication of topology-optimized cages using bioresorbable materials, offering several advantages including customization, and lower stiffness. Delivery of BMP-2 using topology optimization may enhance the quality of fusion.

METHODS

Twenty-two 6-month-old pigs underwent anterior cervical discectomy fusion at one level using 3D printed PCL cages. Experimental groups (N=6 each) included: Group 1: ring design with surface adsorbed BMP-2, Group 2: topology-optimized rectangular design with surface adsorbed BMP-2, and Group 3: ring design with BMP-2 delivery via collagen sponge. Additional specimens, two of each design, were implanted without BMP-2, as controls. Complete cervical segments were harvested six months postoperatively. Nanocomputed tomography was performed to assess complete bony bridging. Pure moment biomechanical testing was conducted in all three planes, separately. Continuous 3D motions were recorded and analyzed.

RESULTS

Three subjects suffered early surgical complications and were not evaluated. Overall, ROM for experimental specimens, regardless of design or BMP-2 delivery method, was comparable, with no clinically significant differences among groups. Among experimental specimens at the level of the fusion, ROM was <1.0° in flexion and extension, indicative of fusion, based on clinically applied criteria for fusion of <2 to 4°. Despite the measured biomechanical stability, using computed tomography evaluation, complete bony bridging was observed in 40% of the specimens in Group 1, 50% of Group 2, 100% of Group 3, and none of the control specimens.

CONCLUSION

A topology-optimized PCL cage with BMP-2 is capable of resulting in an intervertebral fusion, similar to a conventional ring-based design of the same bioresorbable material.

Respiratory Compromise After Anterior Cervical Spine Surgery: Incidence, Subsequent Complications, and Independent Predictors

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Respiratory compromise (RC) is a rare but catastrophic complication of anterior cervical spine surgery (ACSS) commonly due to compressive fluid collections or generalized soft tissue swelling in the cervical spine. Established risk factors include operative duration, size of surgical exposure, myelopathy, among others. The purpose of this current study is to identify the incidence and clinical course of patients who develop RC, and identify independent predictors of RC in patients undergoing ACSS for cervical spondylosis.

METHODS

A large, prospectively-collected registry was used to identify patients undergoing ACSS for spondylosis. Patients with posterior cervical procedures were excluded. Baseline patient characteristics were compared using bivariate analysis, and multivariate analysis was employed to compare postoperative complications and identify independent predictors of RC.

RESULTS

298 of 52,270 patients developed RC (incidence 0.57%). Patients who developed RC had high rates of 30-day mortality (11.7%) and morbidity (75.8%), with unplanned reoperation and pneumonia the most common. The most common reason for reoperations were hematoma evacuation and tracheostomy. Independent patient-specific factors predictive of RC included increasing patient age, male gender, comorbidities such as chronic cardiac and respiratory disease, preoperative myelopathy, prolonged operative duration, and 2-level ACCFs.

CONCLUSION

This is among the largest cohorts of patients to develop RC after ACSS identified to-date and validates a range of independent predictors, many previously only described in case reports. These results are useful for taking preventive measures, identifying high risk patients for preoperative risk stratification, and for surgical co-management discussions with the anesthesiology team.

Pseudarthrosis of the Cervical Spine

Pseudarthrosis of the cervical spine represents a common and challenging problem for spine surgeons. Rates vary greatly from as low as 0%-20% to >60% and depend heavily on patient factors, approach, and number of levels. While some patients remain asymptomatic from pseudarthrosis, many require revision surgery due to instability, continued neck pain, or radiculopathy/myelopathy. We aimed to provide a practical, narrative review of cervical pseudarthrosis to address the following areas: (1) definitions, (2) incidence, (3) risk factors, (4) presentation and workup, (5) treatment decision-making, and (6) postoperative care. It is our hope the current review provides a concise summary for how to diagnose and treat challenging cervical nonunions.

A Matched Cohort Analysis of Drain Usage in Elective Anterior Cervical Discectomy and Fusion: A Michigan Spine Surgery Improvement Collaborative (MSSIC) Study

STUDY DESIGN

This is a retrospective, cohort analysis of multi-institutional database.

OBJECTIVE

This study was designed to analyze the impact of drain use following elective anterior cervical discectomy and fusion (ACDF) surgeries.

SUMMARY OF BACKGROUND DATA

After ACDF, a drain is often placed to prevent postoperative hematoma. However, there has been no high quality evidence to support its use with ACDF despite the theoretical benefits and risks of drain placement.

METHODS

The Michigan Spine Surgery Improvement Collaborative database was queried to identify all patients undergoing elective ACDF between February 2014 and October 2019. Cases were divided into two cohorts based on drain use. Propensity-score matching was utilized to adjust for inherent differences between the two cohorts. Measured outcomes included surgical site hematoma, length of stay, surgical site infection, dysphagia, home discharge, readmission within 30 days, and unplanned reoperation.

RESULTS

We identified 7943 patients during the study period. Propensity-score matching yielded 3206 pairs. On univariate analysis of matched cohorts, there were no differences in rate of postoperative hematoma requiring either return to OR or readmission. We noted patients with drains had a higher rate of dysphagia (4.6% vs. 6.3%; P = 0.003) and had longer hospital stay (P < 0.001). On multivariate analysis, drain use was associated with significantly increased length of stay (relative risk 1.23, 95% confidence interval [CI] 1.13-1.34; P < 0.001). There were no significant differences in other outcomes measured.

CONCLUSION

Our analysis demonstrated that drain use is associated with significant longer hospital stay.Level of Evidence: 3.

Comparison of Outcomes Between Cage Materials Used for Patients Undergoing Anterior Cervical Discectomy and Fusion with Standalone Cages: A Systematic Review and Meta-Analysis

INTRODUCTION

Interbody cages are currently being used to address diseases of the vertebra requiring surgical stabilization. Titanium cages were first introduced in 1988. Polyetheretherketone (PEEK) cages are used frequently as one of the alternatives to titanium cages in current practice. This study aimed to compare available cage materials by reviewing the surgical and radiographic outcomes following anterior cervical discectomy and fusion.

METHODS

A comprehensive search of several electronic databases was conducted following the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines. Baseline characteristics, operative outcomes, arthrodesis rates, subsidence rates, and complications were collected from included studies. Collected outcomes were further stratified according to the procedure type, the number of levels operated, and graft used to compare cage materials.

RESULTS

Following the screening for inclusion criteria, a total of 37 studies with 2363 patients were included. The median age was 49.5 years and the median follow-up was 26 months. Overall, no significant differences were found between PEEK and titanium cages regarding fusion, neurologic deficit, subsidence rates, or "good and excellent" outcome according to Odom criteria. However, the standalone comparison between PEEK, titanium, and poly-methyl-methacrylate (PMMA) cages showed a significantly lower fusion rate for PMMA (PEEK: 94%, PMMA: 56%, titanium: 95%, P < 0.01).

CONCLUSIONS

In the present systematic review and meta-analysis, a comparison of the long-term patient-reported and the radiographic outcomes associated with the use of titanium and PEEK, intervertebral body cages showed similar findings. However, there were significantly lower fusion rates for PMMA cages when using a standalone cage without graft material.

Hybrid Anterior Cervical Discectomy and Fusion and Cervical Disc Arthroplasty: An Analysis of Short-Term Complications, Reoperations, and Readmissions

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Although cervical disc arthroplasty (CDA) has become a well-established and effective treatment for symptomatic cervical degeneration, many patients with multilevel disease are not good candidates for CDA at all levels. For such patients, hybrid surgery (HS)-a combination of adjacent anterior cervical discectomy and fusion (ACDF) and CDA-may be more appropriate. Given the novelty of HS and the relative dearth of studies adequately assessing short-term perioperative complications, this current study sought to assess the short-term morbidity profile of HS, differences in operative duration, length of stay (LOS), and readmission and reoperation rates and reasons relative to a 2-level ACDF cohort.

METHODS

All patients who underwent HS and 2-level ACDF were identified between 2011 and 2018 using a large, prospectively collected registry. Baseline patient characteristics and postoperative complications were compared using bivariate and/or multivariate analysis.

RESULTS

A total of 390 patients undergoing HS were identified. Two-level procedures were the most common (74.9%). Patients undergoing HS were more likely to be younger, male, and have fewer comorbidities. There were no differences between HS and 2-level ACDF in rates of any postoperative complication, transfusion, readmissions, and operative duration. However, HS had a decreased LOS (0.5 days), relative to a 2-level ACDF. HS patients had low rates of reoperation (1.28%) with 1 case for hematoma evacuation and another for revision CDA.

CONCLUSIONS

This study represents one of the largest cohorts of patients undergoing HS reported to date. Patients undergoing HS are not at increased risk of perioperative complications relative to a 2-level ACDF and may benefit from shorter LOS.

The effects of cages implantation on surgical and adjacent segmental intervertebral foramina

Objection

The overarching goal of our research was to compare the clinical and radiological outcomes with different sizes of cages implantation in anterior cervical discectomy and fusion (ACDF), and to evaluate the effects on surgical and adjacent segmental intervertebral foramina.

Methods

The clinical data of 61 patients were analyzed retrospectively. The radiological data included the surgical intervertebral disk space height before (H₀) and after surgery (H), the preoperative mean height of adjacent segments (H_m), the area and height of the surgical and adjacent segment foramen, the surgical segmental Cobb angle (α₁), and C2-7Cobb angle (α₂). The calculation of clinical data was conducted by Japanese Orthopaedic Association Scores (JOA), the recovery rate of JOA scores and visual analog scales (VAS). In accordance with the different ranges of distraction (H/H_m), patients were classified into three groups: group A (H/H_m<1.20, n=13), group B (1.20≤H/H_m≤1.80, n=37), and group C (H/H_m>1.80, n=11).

Results

After the operation and at the final follow-up, our data has demonstrated that the area and height of surgical segmental foramen all increased by comparing those of preoperation in three groups (all P<0.05). However, except for a decrease in group C (all P<0.05), the adjacent segmental foramina showed no significant changes (all P>0.05). The area and height of the surgical segment foramen and the distraction degree were positively correlated (0<R<1, all P<0.05), while the adjacent segments were negatively correlated with it (0<R<1, P=0.002~0.067). JOA scores improved markedly in all groups with similar recovery rates. However, during the final follow-up (P=0.034), it was observed that there were significant differences in visual simulation scores among the three groups.

Conclusion

The oversize cage might give a rise to a negative impact on the adjacent intervertebral foramen in ACDF. The mean value of the adjacent intervertebral disk space height (H_m) could be used as a reference standard. Moreover, the 1.20~1.80 fold of distraction (H/H_m) with optimal cages would achieve a better long-term prognosis.

Adjacent Segment Pathology After Treatment With Cervical Disc Arthroplasty or Anterior Cervical Discectomy and Fusion, Part 2: Clinical Results at 7-Year Follow-Up

Background

Adjacent segment pathology (ASP) following cervical disc arthroplasty (CDA) or anterior cervical discectomy and fusion (ACDF) is identified by imaging (RASP) or clinical symptoms (CASP). Clinical symptoms of CASP have been broadly defined, but subsequent adjacent-level surgeries are clear indicators of CASP. Current literature remains inconsistent in the incidence and potential predictors of CASP. Here, we will evaluate a robust data set for the incidence of CASP resulting in subsequent surgery, attempt to identify factors that might affect CASP, and analyze the association of CASP with patient-reported outcomes (PROS) and RASP.

Methods

Data were prospectively collected during a US Food and Drug Administration randomized, multicenter, investigational device exemption trial comparing CDA (Mobi-C, Zimmer Biomet, Westminster, CO) with ACDF. CASP was defined as any adjacent-level subsequent surgical intervention. Post hoc analyses were conducted on the incidence, time to CASP diagnosis, and relationship of CASP with patient demographics. Longitudinal retrospective case-control analysis was used to assess the correlation of CASP to PROs and radiographic adjacent segment pathology (RASP).

Results

Kaplan-Meier estimates indicated significantly lower probability of CASP over time for 1-level (P = .002) and 2-level (P = .008) CDA patients. Treatment with ACDF and younger age were associated with higher CASP risk. CDA was more effective than ACDF (70.5%; 95% CI = 45.1, 84.2; P < .0001) at preventing CASP. Case-control analysis indicated increased probability of CASP for patients with grade 3/4 RASP, but the difference was not statistically significant. When we pooled CASP patients, the median grade of RASP at the visit prior to surgery was 1, with only 6 patients presenting with grade 3/4 RASP.

Conclusions

Patients treated with CDA have a lower incidence of CASP than do patients treated with ACDF, although the mechanism remains unclear. CASP and RASP remain uncorrelated in this large data set, but other predictive variables such as treatment, age, and number of levels should be further investigated.

Retropharyngeal hematoma following anterior cervical spine surgery: Lessons from a case report (CARE-compliant)

RATIONALE

Retropharyngeal hematoma (RH) is an infrequent but potentially life-threatening complication of anterior cervical spine surgeries (ACSS). Challenging situations might be confronted and catastrophic events or even deaths still occurred occasionally during the treatment. Currently, no widely accepted protocol has been developed.

PATIENT CONCERNS

A 55 years old male underwent ACSS due to cervical myelopathy. Thirty-three hours after surgery the patient presented cervical swelling and obstructive dysphagia. Conservative treatment resulted in no recovery and cervical swelling progressed.

DIAGNOSES

Emergent magnetic resonance imaging and plain radiograph established massive incisional and RHs. RH was shown to extend from the base of the skull to T1.

INTERVENTIONS

An emergent surgery was performed under local anesthesia and cervical hematoma was evacuated. Nonetheless, evacuation of the blood clots in the vision field resulted into incomplete recovery of throat blockage. A gloved finger was used to explore the retropharyngeal space and some hidden blood clots were found and evacuated, then the patient obtained complete relief of the symptoms.

OUTCOMES

Normal respiration and swallowing functions were obtained after the surgery. Obviously, recovery of motor function was noted while no other complication was found at 3-month follow-up LESSONS:: Our case illustrated that dysphagia was an early symptom of RH. Posterior compression from RH could cause obstruction of the pharyngeal airway and lead to difficulty of intubation. Hematoma could spread through the retropharyngeal space, a hematoma exploration beyond the visual range might be necessary in some cases for fear of the hidden hematoma.

Comparison of radiological outcomes and complications between single-level and multilevel anterior cervical discectomy and fusion (ACDF) by using a polyetheretherketone (PEEK) cage-plate fusion system

This study aimed to compare the differences in radiological outcomes and complications between single- and multilevel anterior cervical discectomy and fusion (ACDF) by using a polyetheretherketone (PEEK) cage-plate fusion system.Fifty-seven patients who underwent ACDF via the PEEK cage-plate fusion system were enrolled and subjected to ≥6 months of follow-up. The patients were divided into 4 groups according to different cage-plate implantation levels: 1-level group (n = 17), 2-level group (n = 24), 3-level group (n = 12), and 4-level group (n = 4). Fusion time, changes in segment and global lordotic angle, subsidence rate, and changes in disc and adjacent segmental disc height were subjected to radiological evaluation.The fusion period of multilevel ACDF was longer than that of single-level ACDF. The fusion period of the 3-level (4.09 ± 0.94, P = .004) and 4-level (5.25 ± 0.89, P = .004) group was also significantly longer than that of the 1-level group. The mean lordotic angle in all of the groups was changed in the immediate postoperative period and in the final follow-up. The cage subsidence rates were 11.76% (2/17) in the 1-level group, 20.83% (5/24) in the 2-level group, and 2/12 (16.67%) in the 3-level group. No subsidence occurred in the 4-level groups. Changes in the lower adjacent segmental disc height were significantly increased in multilevel ACDF compared with those in single-level ACDF.Despite the longer fusion time, the outcomes of the proposed system were even better with the greater number of treatment levels by using PEEK cage-plate fusion system. Changes in the lower adjacent segmental disc height should also prolong follow-up duration to investigate the symptomatic adjacent segment degeneration in multilevel ACDF.

Clinical presentation and outcome after anterior cervical discectomy and fusion for degenerative cervical disc disease

Background:

Anterior cervical discectomy and fusion (ACDF) is a well-described surgical approach for symptomatic degenerative cervical disc disease which does not respond to conservative management. In the present study, we assessed clinical presentation and outcomes of ACDF.

Materials and Methods:

The present study was conducted from October 1, 2015, to October 31, 2017, in the Department of Neurosurgery, Narayana Medical College and Hospital, Nellore, Andhra Pradesh, among 100 consecutive adult patients who underwent single- or two-level ACDF for degenerative cervical disc disease.

Results:

The mean age was 47.2 ± 12.8 years (range: 20–74 years). Majority of the patients were male (86/100). Presenting symptoms were neck pain (77%), limb weakness (73%), paresthesias (53%), radicular pain (49%), stiffness in limbs (16%), and bladder involvement (13%). Fusion was done with stand-alone titanium cage/bone graft or titanium cage/bone graft with anterior cervical plate. At the time of discharge, significant improvement in preoperative symptoms (neck pain [47/77-61%], radicular pain [31/49-63%], limb weakness [53/73-72.6%], paresthesias [44/53-83%], stiffness in limbs [13/16-81%], and bladder symptoms [8/13-61%]) was reported by majority of these patients. Majority of these patients also reported improvement in preoperative sensory deficits at the time of discharge. Postoperative complications were hoarseness of voice (22%), dysphagia (16%), deterioration of motor power (8%), and postoperative hematoma (7%).

Conclusions:

A significant proportion of patients with degenerative cervical disc disease show remarkable recovery after ACDF.

Radiological Fusion Criteria of Postoperative Anterior Cervical Discectomy and Fusion: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVES

Diagnosis of pseudarthrosis after anterior cervical fusion is difficult, and often depends on the surgeon's subjective assessment because recommended radiographic criteria are lacking. This review evaluated the available evidence for confirming fusion after anterior cervical surgery.

METHODS

Articles describing assessment of anterior cervical fusion were retrieved from MEDLINE and SCOPUS. The assessment methods and fusion rates at 1 and 2 years were evaluated to identify reliable radiographical criteria.

RESULTS

Ten fusion criteria were described. The 4 most common were presence of bridging trabecular bone between the endplates, absence of a radiolucent gap between the graft and endplate, absence of or minimal motion between adjacent vertebral bodies on flexion-extension radiographs, and absence of or minimal motion between the spinous processes on flexion-extension radiographs. The mean fusion rates were 90.2% at 1 year and 94.7% at 2 years. The fusion rate at 2 years had significant independence (P = .048).

CONCLUSIONS

The most common fusion criteria, bridging trabecular bone between the endplates and absence of a radiolucent gap between the graft and endplate, are subjective. We recommend using <1 mm of motion between spinous processes on extension and flexion to confirm fusion.

Bioabsorbable self-retaining PLA/nano-sized β-TCP cervical spine interbody fusion cage in goat models: an in vivo study

STUDY DESIGN

This is an experimental animal study.

OBJECTIVE

The objective of this study was to compare an anterior cervical discectomy and interbody fusion of a novel polylactide/nano-sized β-tricalcium phosphate (PLA/nβ-TCP) bioabsorbable self-retaining cervical fusion cage (BCFC) with an autologous bone graft and polyetheretherketone (PEEK) cages.

BACKGROUND

Although PLA cervical cages have potential advantages compared with traditional materials, they are not currently routinely used in spine surgery because of undesirable effects such as the lack of osteoconductivity and osteolysis around the implant. This study involved the manufacturing of a bioabsorbable cage from PLA/nβ-TCP that was then used as a device for anterior cervical discectomy and fusion (ACDF) on a goat cervical spine fusion model.

MATERIALS AND METHODS

Eighteen goats underwent C3/C4 discectomy and were randomly divided into three groups based on the following methods: Group A (n=6), an autologous bone graft; Group B (n=6), PEEK cage filled with an autologous graft; and Group C (n=6), BCFC filled with an autologous iliac bone. Radiography was performed preoperatively and postoperatively and at 1, 4, 8, and 12 weeks after the operation. Disc space height (DSH) was measured at the same time. After 12 weeks, the fused segments were harvested and evaluated with functional radiographic views, biomechanical testing, and histological analyses.

RESULTS

Over a 12-week period, the BCFC and PEEK cage groups exhibited significantly higher DSH values than the bone graft group. Additionally, the BCFC group yielded a significantly lower range of motion in axial rotation than both the autologous bone graft and PEEK cage groups. A histologic evaluation revealed an increased intervertebral bone volume/total volume ratio and better interbody fusion in the BCFC group than in the other groups.

CONCLUSION

The BCFC device exhibited better results than the autologous bone graft and PEEK cages in single-level ACDF models in vivo. This device may be a potential alternative to the current PEEK cages.

Clinical Application of Ceramics in Anterior Cervical Discectomy and Fusion: A Review and Update

STUDY DESIGN

Narrative review.

OBJECTIVES

Anterior cervical discectomy and fusion (ACDF) is a reliable procedure, commonly used for cervical degenerative disc disease. For interbody fusions, autograft was the gold standard for decades; however, limited availability and donor site morbidities have led to a constant search for new materials. Clinically, it has been shown that calcium phosphate ceramics, including hydroxyapatite (HA) and tricalcium phosphate (TCP), are effective as osteoconductive materials and bone grafts. In this review, we present the current findings regarding the use of ceramics in ACDF.

METHODS

A review of the relevant literature examining the clinical use of ceramics in anterior cervical discectomy and fusion procedures was conducted using PubMed, OVID and Cochrane.

RESULT

HA, coralline HA, sandwiched HA, TCP, and biphasic calcium phosphate ceramics were used in combination with osteoinductive materials such as bone marrow aspirate and various cages composed of poly-ether-ether-ketone (PEEK), fiber carbon, and titanium. Stand-alone ceramic spacers have been associated with fracture and cracks. Metallic cages such as titanium endure the risk of subsidence and migration. PEEK cages in combination with ceramics were shown to be a suitable substitute for autograft.

CONCLUSION

None of the discussed options has demonstrated clear superiority over others, although direct comparisons are often difficult due to discrepancies in data collection and study methodologies. Future randomized clinical trials are warranted before definitive conclusions can be drawn.

Predictors for Airway Complications Following Single- and Multilevel Anterior Cervical Discectomy and Fusion

STUDY DESIGN

A retrospective, multivariate analyses of a prospectively collected multicenter database.

OBJECTIVE

The aim of this study was to evaluate the risk factors for postoperative airway complications following single- and multilevel anterior cervical discectomy and fusion (ACDF).

SUMMARY OF BACKGROUND DATA

Airway compromise following ACDF may result in catastrophic outcome. However, its predictors have not been identified by a multi-institutional study.

METHODS

Patients who underwent ACDF between 2011 and 2013 were selected from the American College of Surgeons National Surgical Quality Improvement Program database. Multiple logistic regression analysis was performed to identify the risk factors for airway compromise following ACDF.

RESULTS

Twelve thousand one hundred eighty-five patients were analyzed in this study. Our multivariate analysis identified older age, male gender, dependent functional status, chronic obstructive pulmonary disease, bleeding disorder, American Society of Anesthesiology class >2, Wound Class >2, and prolonged operative durations as significant predictors of postoperative airway compromise following ACDF. Surprisingly, multilevel and corpectomy procedures were not significant risk factors for airway complication following ACDF.

CONCLUSION

We identified significant risk factors for airway compromise following ACDF procedures. While ACDF is considered a safe procedure, postoperative airway complication can lead to disastrous outcome. Continued efforts to elucidate preoperative risk factors and subsequent optimization are warranted to improve outcomes in ACDF.

LEVEL OF EVIDENCE

3.

Acute airway obstruction due to postoperative retropharyngeal hematoma after anterior cervical fusion: a retrospective analysis

Background

Acute airway obstruction (AAO) after anterior cervical fusion (ACF) can be caused by postoperative retropharyngeal hematoma, which requires urgent recognition and treatment. However, the causes, evaluation, and appropriate treatment of this complication are not clearly defined. The purpose of this retrospective review of a prospective database was to investigate etiologic factors related to the development of AAO due to postoperative hematoma after ACF and formulate appropriate prevention and treatment guidelines.

Methods

Cervical spinal cases treated at our academic institutions from 1998 to 2013 were evaluated. Demographic data, including factors related to hemorrhagic tendency, and operative data were analyzed. Patients who developed a hematoma were compared with those who did not to identify risk factors. Cases complicated by hematoma were reviewed, and times until development of hematoma and surgical evacuation were determined. Degrees of airway compromise and patient behavior were classified and evaluated. Treatment was selected according to the patient’s status.

Results

Among 785 ACF procedures performed, there were nine cases (1.15%) of AAO. None of these nine patients had preoperative risk factors. In six patients (67%), the hematoma occurred within 24 h, whereas three patients (33%) presented with hematoma at a median of 72 h postoperatively. Four of the nine patients with AAO underwent evacuation of the hematoma. Two patients with inspiratory stridor, anterior neck swelling, and facial edema progressed to respiratory distress and their hematomas were removed by surgery, during which, sustained superficial venous bleeding was confirmed. Intubation was attempted several times in one patient with cyanosis, but is unsuccessful; cricothyroidotomy was performed in this patient and pumping in the small muscular arterial branches was confirmed in the operating room. All of the patients recovered without any complications.

Conclusions

With rapid recognition and appropriate treatment, there were no long-term complications caused by postoperative hematoma. There were no specific preoperative risk factors for hematoma. Systematic evaluation and appropriate management can be helpful for preventing serious complications after development of a postoperative hematoma.

Comparison of Cervical Kinematics, Pain, and Functional Disability Between Single- and Two-level Anterior Cervical Discectomy and Fusion

STUDY DESIGN

A prospective, time series design.

OBJECTIVE

The purpose of this study is two-fold: firstly, to investigate the impact of altered cervical alignment and range of motion (ROM) on patients' self-reported outcomes after anterior cervical discectomy and fusion (ACDF), and secondly, to comparatively differentiate the influence of single- and two-level ACDF on the cervical ROM and adjacent segmental kinematics up to 12-month postoperatively.

SUMMARY OF BACKGROUND DATA

ACDF is one of the most commonly employed surgical interventions to treat degenerative disc disease. However, there are limited in vivo data on the impact of ACDF on the cervical kinematics and its association with patient-reported clinical outcomes.

METHODS

Sixty-two patients (36 males; 55.63 ± 11.6 yrs) undergoing either a single- or consecutive two-level ACDF were recruited. The clinical outcomes were assessed with the Pain Visual Analogue Scale (VAS) and the Neck Disability Index (NDI). Radiological results included cervical lordosis, global C2-C7 ROM, ROM of the Functional Spinal Unit (FSU), and its adjacent segments. The outcome measures were collected preoperatively and then at 3, 6, and 12-month postoperatively.

RESULTS

A significant reduction of both VAS and NDI was found for both groups from the preoperative to 3-month period (P < 0.01). Pearson correlation revealed no significant correlation between global ROM with neither VAS (P = 0.667) nor NDI (P = 0.531). A significant reduction of global ROM was identified for the two-level ACDF group at 12 months (P = 0.017) but not for the single-level group. A significant interaction effect was identified for the upper adjacent segment ROM (P = 0.024) but not at the lower adjacent segment.

CONCLUSION

Current study utilized dynamic radiographs to comparatively evaluate the biomechanical impact of single- and two-level ACDF. The results highlighted that the two-level group demonstrated a greater reduction of global ROM coupled with an increased upper adjacent segmental compensatory motions that is independent of patient-perceived recovery.

LEVEL OF EVIDENCE

3.

Long-Term Follow-Up Results of Anterior Cervical Inter-Body Fusion with Stand-Alone Cages

Objective

The purpose of this study was to evaluate long-term follow-up radiologic/clinical outcomes of patients who underwent anterior cervical discectomy and inter-body fusion (ACDF) with stand-alone cages (SAC) in a single academic institution.

Methods

Total 99 patients who underwent ACDF with SAC between February 2004 and December 2012 were evaluated retrospectively. A total of 131 segments were enrolled in this study. Basic demographic information, radiographic [segmental subsidence rate, fusion rate, C2–7 global angle, and segmental angle changes)/clinical outcomes (by Odom's criteria and visual analog score (VAS)] and complications were evaluated to determine the long-term outcomes.

Results

The majority were males (55 vs. 44) with average age of 53.2. Mean follow-up period was 62.9 months. The segmental subsidence rate was 53.4% and fusion rate was 73.3%. In the subsidence group, anterior intervertebral height (AIH) had more tendency of subsiding than middle or posterior intervertebral height (p=0.01). The segmental angle led kyphotic change related to the subsidence of the AIH. Adjacent segmental disease was occurred in 18 (18.2%) patients. Total 6 (6%) reoperations were performed at the index level. There was no statistical significance between clinical and radiological outcomes. But, overall long-term clinical outcome by Odom's criteria was unsatisfactory (64.64%). The neck and arm VAS score were increased by over time.

Conclusion

Long-term outcomes of ACDF with SAC group were acceptable but not satisfactory. For optimal decision making, more additional comparative long-term outcome data is needed between ACDF with SAC and ACDF with plating.

Prevalence of adjacent segment disease following cervical spine surgery: A PRISMA-compliant systematic review and meta-analysis

Prevalence estimates of adjacent segment degeneration (ASD) following cervical spine surgery varied greatly in current studies. We conducted a systematic review and meta-analysis to summarize the point prevalence of ASD after cervical spine surgery.

METHODS

Comprehensive electronic searches of PubMed, Embase, Web of Knowledge, and Cochrane Library databases were conducted to identify any study published from initial state to January 2016. Those reporting the prevalence of ASD after cervical surgery were included. A random-effects model was used to estimate the prevalence of radiographic ASD, symptomatic ASD, and reoperation ASD. Univariate meta-regression analyses were conducted to explore the potential associations between prevalence and length of follow-up. All analyses were performed using R version 3.2.3 (R Foundation for Statistical Computing).

RESULTS

A total of 83 studies were included in the meta-analysis. The prevalence of radiographic ASD, symptomatic ASD, and reoperation ASD after cervical surgery was 28.28% (95% confidence interval [CI], 20.96-36.96), 13.34% (95% CI, 11.06-16.00), and 5.78% (95% CI, 4.99-6.69), respectively, in a general analysis. It was found 2.79%, 1.43%, and 0.24% additions per year of follow-up in the incidence of radiographic ASD, symptomatic ASD, and reoperation ASD, respectively.

CONCLUSION

This meta-analysis provides some details about the prevalence of radiographic ASD, symptomatic ASD, and reoperation ASD after cervical spine surgery. However, the results of this meta-analysis should be interpreted with caution because of the heterogeneity among the studies.

Adjacent Segment Pathology after Anterior Cervical Fusion

Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion.

A minimum 2-year comparative study of autologous cancellous bone grafting versus beta-tricalcium phosphate in anterior cervical discectomy and fusion using a rectangular titanium stand-alone cage

Although titanium stand-alone cages are commonly used in anterior cervical discectomy and fusion (ACDF), there are several concerns such as cage subsidence after surgery. The efficacy of β-tricalcium phosphate (β-TCP) granules as a packing material in 1- or 2-level ACDF using a rectangular titanium stand-alone cage is not fully understood. The purpose of this study is to investigate the validity of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP. This retrospective study included 55 consecutive patients who underwent ACDF with autologous iliac cancellous bone grafting and 45 consecutive patients with β-TCP grafting. All patients completed at least 2-year postoperative follow-up. Univariate and multivariate analyses were performed to examine the associations between study variables and nonunion after surgery. Significant neurological recovery after surgery was obtained in both groups. Cage subsidence was noted in 14 of 72 cages (19.4 %) in the autograft group and 12 of 64 cages (18.8 %) in the β-TCP group. A total of 66 cages (91.7 %) in the autograft group showed osseous or partial union, and 58 cages (90.6 %) in the β-TCP group showed osseous or partial union by 2 years after surgery. There were no significant differences in cage subsidence and the bony fusion rate between the two groups. Multivariate analysis using a logistic regression model showed that fusion level at C6/7, 2-level fusion, and cage subsidence of grades 2-3 were significantly associated with nonunion at 2 years after surgery. Although an acceptable surgical outcome with negligible complication appears to justify the use of rectangular titanium stand-alone cages in 1- and 2-level ACDF with β-TCP, cage subsidence after surgery needs to be avoided to achieve acceptable bony fusion at the fused segments. Fusion level at C6/7 or 2-level fusion may be another risk factor of nonunion.

Polyetheretherketone (PEEK) cages in cervical applications: a systematic review

BACKGROUND CONTEXT

Polyetheretherketone (PEEK) cages have been widely used during the past decade in patients with degenerative disorders of the cervical spine. Their radiolucency and low elastic modulus make them attractive attributes for spinal fusion compared with titanium and bone graft. Still, limitations are seen such as pseudoarthrosis, subsidence, and migration of the cages. Limited evidence on the clinical outcome of PEEK cages is found in the literature other than noncomparative cohort studies with only a few randomized controlled trials.

PURPOSE

To assess the clinical and radiographic outcome of PEEK cages in the treatment of degenerative disc disorders and/or spondylolisthesis in the cervical spine.

STUDY DESIGN

Systematic review of all randomized controlled trials and prospective and retrospective nonrandomized comparative studies with a minimum follow-up of 6 months and all noncomparative cohort studies with a long-term follow-up of more than 5 years.

OUTCOME MEASURES

The primary outcome variable was clinical performance. Secondary outcome variables consisted of radiographic scores.

METHODS

The MEDLINE, EMBASE, and Cochrane Library databases were searched according to the Preferred Reporting Items of Systematic reviews and Meta-Analyses statement and Meta-analysis Of Observational Studies in Epidemiology guidelines. No conflict of interest reported. No funding received.

RESULTS

A total of 223 studies were identified, of which 10 studies were included. These comprised two randomized controlled trials, five prospective comparative trials, and three retrospective comparative trials.

CONCLUSIONS

Minimal evidence for better clinical and radiographic outcome is found for PEEK cages compared with bone grafts in the cervical spine. No differences were found between PEEK, titanium, and carbon fiber cages. Future studies are needed to improve methodology to minimize bias. Publication of lumbar interbody fusion studies needs to be promoted because differences in clinical and/or radiographic scores are more likely to be demonstrated in this part of the spine.

Reoperation rates after anterior cervical discectomy and fusion versus posterior cervical foraminotomy: a propensity-matched analysis

BACKGROUND CONTEXT

Anterior cervical discectomy and fusion (ACDF) and posterior cervical foraminotomy (PCF) are both used to surgically treat patients with cervical radiculopathy and have been shown to have similar outcomes. Nonetheless, ACDF has become increasingly more commonplace compared with PCF, in part because of a pervasive belief that PCF has a higher incidence of required reoperations.

PURPOSE

To determine the reoperation rate at the index level of ACDF versus PCF 2 years postoperatively.

STUDY DESIGN

A retrospective case-control.

PATIENT SAMPLE

All patients that underwent ACDF and PCF for radiculopathy (excluding myelopathy indications) between January 2005 and December 2011.

OUTCOME MEASURES

Revision surgery within 2 years, at the index level, was recorded.

METHODS

Propensity score analysis between the ACDF and PCF groups was done, matching for age, gender, race, body mass index, tobacco use, median income and insurance status, primary surgeon, level of surgery, surgery duration, and length of hospital stay.

RESULTS

Seven hundred ninety patients met the inclusion/exclusion criteria, including 627 ACDF and 163 PCF. Before propensity matching, the PCF group was found to be significantly older and more likely to be male. After matching, there were no significant differences between groups for any baseline characteristics. Reoperation rate at the index level was 4.8% for the ACDF group and 6.4% for the PCF group (p=.7) within 2 years of the initial surgery. Using equivalence testing, based on an a priori null hypothesis that a clinically meaningful difference between the two groups would be ≥5%, we found that the absolute difference of 1.6% was significantly (p=.01) less than our hypothesized difference.

CONCLUSIONS

This study demonstrates that even after accounting for patient demographics, operative characteristics, and primary surgeon, there are no significant differences in 2-year reoperation rates at the index level between ACDF and PCF. The reoperation rates are statistically equivalent. Thus, spine surgeons can operate via the posterior approach without putting patients at increased risk for revision surgery at the index level.

Rates of anterior cervical discectomy and fusion after initial posterior cervical foraminotomy

BACKGROUND CONTEXT

In select patients, posterior cervical foraminotomy (PCF) and anterior cervical discectomy and fusion (ACDF) result in similar clinical outcomes when used to treat cervical radiculopathy. Nonetheless, ACDF is performed more frequently, in part because of surgeon perception that PCF requires operative revisions more frequently. The present study investigates the rate of ACDF reoperation at the index level after initial PCF.

PURPOSE

To determine the rate of ACDF after initial PCF and to further describe any patient characteristics or preoperative or operative data that increase the rate of reoperation after PCF.

STUDY DESIGN

Retrospective chart review.

METHODS

Demographic, operative, and reoperation information was collected from the electronic medical records for all patients who underwent PCF at one institution between 2004 and 2011. All patients were subsequently contacted by telephone to identify postoperative complications and more conclusively determine whether any revision operation was performed at the index level.

RESULTS

One hundred seventy-eight patients who underwent a PCF were reviewed, with an average follow-up of 31.7 months. Nine (5%) patients underwent an ACDF revision operation at the index level. The reason for reoperation in these patients included cervical radiculopathy, foraminal stenosis, disc herniation, and cervical spondylosis. Patients who subsequently underwent ACDF at the index level were significantly younger (25 vs. 35 years, p=.03), had lower body mass index (25 vs. 29, p=.01), and more likely to take anxiolytic (56% vs. 22%, p=.04) or antidepressant medication (67% vs. 27%, p=.02), compared with those that did not have a revision operation.

CONCLUSIONS

This is the first study to determine conversion to ACDF after PCF. The present study demonstrates that PCF is associated with a low reoperation rate, similar to the historical reoperation for ACDF. Accordingly, spine surgeons can operate via a PCF approach without a significant increased risk for ACDF revision surgery at the index level.

Differential segmental motion contribution of single- and two-level anterior cervical discectomy and fusion

PURPOSE

To determine and compare the biomechanical effects of single- and two-level anterior cervical decompression and fusion (ACDF) on the re-distribution of the segmental contribution to total cervical range of motion (ROM) in a prospective longitudinal design.

METHODS

Fifty-one patients undergoing either a single- or two-level ACDF due to cervical disc disease were recruited. Functional radiographs were taken preoperatively and then at 3, 6 and 12-month follow-ups. Global ROM of C2-C7, ROM of the treated functional spinal unit (FSU) and the superior and inferior segmental ROMs were then measured. The relative contribution from the FSU and each of the adjacent segments to total cervical ROM were compared pre- and post-operatively within and between the two groups at each of the time points.

RESULTS

Single-level ACDF patients demonstrated a significantly greater total cervical ROM at 6 and 12 months compared with the two-level ACDF group (p = 0.021 and 0.045, respectively). A significantly greater contribution from the FSU to the total ROM was found at 3 months in the two-level ACDF group (p = 0.016), but the greater contribution shifted to the superior adjacent segment at 6 and 12 months (p = 0.025 and 0.046). The two-level ACDF group did not demonstrate a significant difference at 3 months (p = 0.087), but a significant increase in contribution was found at 6 and 12 months (p < 0.01).

CONCLUSIONS

Single-level ACDF maintains and restores a more physiological re-distribution of segmental contribution of ROM compared with two-level ACDF, which required longer time to achieve stable FSU immobilization and coupled with significantly increased superior segment contribution.

Comparison of outcomes and safety of using hydroxyapatite granules as a substitute for autograft in cervical cages for anterior cervical discectomy and interbody fusion

BACKGROUND

After cervical discectomy, autogenic bone is packed into the cage to increase the rate of union between adjacent vertebral bodies, but donor site-related complications can still occur. In this study we evaluate the use of hydroxyapatite granules as a substitute for autograft for interbody fusion.

METHODS

From November 2008 to November 2011, 236 patients participated in this study. Peek cages were packed with autologous bone grafts taken from the iliac crest in 112 patients and hydroxyapatite (HA) granules in 124 patients. Patients were followed for 12 months. The patients' neurological signs, results, and complications were fully recorded throughout the procedure. Radiological imaging was done to assess the fusion rate and settling ratio.

RESULTS

Formation of bony bridges at the third month was higher in the autograft group versus the granule group. However, there was no difference between both groups at the 12-month follow-up assessment. No difference (P> 0.05) was found regarding improvement in neurological deficit as well as radicular pain and recovery rate between the two groups.

CONCLUSIONS

Interbody fusion cage containing HA granules proved to be an effective treatment for cervical spondylotic radiculopathy and/or myelopathy. Clinical and neurological outcome, radiographic measurement and fusion rate in cage containing HA are similar and competitive with autograft packed cages.

Risk factors for subsidence in anterior cervical fusion with stand-alone polyetheretherketone (PEEK) cages: a review of 82 cases and 182 levels

INTRODUCTION

To determine risk factors for subsidence in patients treated with anterior cervical discectomy and fusion (ACDF) and stand-alone polyetheretherketone (PEEK) cages.

MATERIALS AND METHODS

Records of patients with degenerative spondylosis or traumatic disc herniation resulting in radiculopathy or myelopathy between C2 and C7 who underwent ACDF with stand-alone PEEK cages were retrospectively reviewed. Cages were filled with autogenous cancellous bone harvested from iliac crest or hydroxyapatite. Subsidence was defined as a decrease of 3 mm or more of anterior or posterior disc height from that measured on the postoperative radiograph. Eighty-two patients (32 males, 50 females; 182 treatment levels) were included in the analysis.

RESULTS

Most patients had 1-2 treatment levels (62.2 %), and 37.8 % had 3-4 treatment levels. Treatment levels were from C2-7. Of the 82 patients, cage subsidence occurred in 31 patients, and at 39 treatment levels. Multivariable analysis showed that subsidence was more likely to occur in patients with more than two treatment levels, and more likely to occur at treatment levels C5-7 than at levels C2-5. Subsidence was not associated with postoperative alignment change but associated with more disc height change (relatively oversized cage).

CONCLUSION

Subsidence is associated with a greater number of treatment levels, treatment at C5-7 and relatively oversized cage use.

Evidence-based analysis of adjacent segment degeneration and disease after ACDF: a systematic review

BACKGROUND CONTEXT

Follow-up studies of patients undergoing anterior cervical discectomy and interbody fusion (ACDF) have demonstrated varying degrees of radiographic degeneration at adjacent levels, with most cases being asymptomatic (adjacent segment degeneration, ASDeg) and far fewer being symptomatic (adjacent segment disease, ASDz). Controversy remains as to whether these conditions are related to altered biomechanics or represent the natural history of cervical spondylosis at the adjacent segment.

PURPOSE

To provide an evidence-based analysis of the peer-reviewed literature on clinical studies of ASDeg and ASDz after ACDF.

STUDY DESIGN/SETTING

Systematic review of existing literature.

METHODS

The MEDLINE database was queried for clinical studies reporting ASDeg and/or ASDz after ACDF. Articles written in the English language with a minimum follow-up of 2 years were independently reviewed and analyzed by two authors, and the level of evidence was assigned. Data were pooled to generate summary outcomes and organized by number of levels, technique, and graft/implants.

RESULTS

Of the 238 articles returned from the MEDLINE database query, 14 met inclusion criteria. An average of 168 patients was enrolled per study with an average follow-up of 106.5 months. Graft materials, cage design, plate fixation system, and length of fusion varied widely. Additionally, no clear standard was seen for radiographic assessment modalities (eg, plain lateral radiograph, flexion-extension radiographs, computed tomography, or magnetic resonance imaging). Validated clinical outcome measures were used in 43% (6/14) of the studies. The average incidence of ASDeg was 47.33% (459.14/970) with a range from 16% to 96%. The frequency-weighted average for ASDz was 11.99% (263.70/2,199) with a range from 1.80% to 36.00%. Follow-up ranged from 24 to 296 months with no reliable commonalities, which prohibited a meta-analysis.

CONCLUSIONS

This review highlights the heterogeneous methodology of the peer-reviewed literature on ASDeg and ASDz after ACDF and the paucity of high-level clinical data published on these conditions. Despite the low level of evidence to define the incidence of ASDeg and ASDz, it is clear that radiographic ASDeg is more common than symptomatic ASDz, indicating that adjacent segment pathology remains subclinical in a large subset of patients. This analysis underscores the need for standardized radiographic measures in the assessment of ASDeg and validated clinical outcome measures for ASDz after ACDF. Consistent methodology and multi-surgeon collaboration may improve the quality of clinical data on ASDeg and ASDz and elucidate the true etiology and incidence of these conditions.

Elastic resistance of the spine: Why does motion preservation surgery almost fail?

Single metamere motility should not be interpreted merely as a movement on the 3 planes but also, and above all, as elastic resistance to dynamic stress on these 3 planes. In the light of this consideration, the aim of motion preservation is to neutralize excessive movements while preserving the physiological biomechanical properties of the metamere involved to interrupt the progression of degenerative processes and to prevent adjacent segment disease. Despite the fact that a myriad of devices have been developed with the purpose of achieving dynamic neutralization of the spine, there are now some doubts regarding the true efficacy of these devices.

Timing of tracheostomy after anterior cervical spine fixation

BACKGROUND

Patients with cervical spinal cord injury frequently undergo early anterior cervical spine fixation (ACSF) and tracheostomy procedures to reduce further deterioration, to reduce risk of pulmonary complications, and to improve patient mobilization. However, tracheostomy is often delayed because of the risk of cross contamination as a result of the proximity to the ACSF incision site. Currently, there is a paucity of studies evaluating this outcome to determine the safety of early tracheostomy after ACSF. In this study, we have evaluated the outcomes and complications associated with early tracheostomy placement.

METHODS

We performed a retrospective review of all patients who underwent tracheostomy placement and ACSF during the same hospitalization between 2005 and 2010. A variety of patient and procedural data were collected, including demographics, timing of ACSF and tracheostomy, length of hospitalization, indication for surgery, American Spinal Injuries Association and Glasgow Coma Scale scores on admission, reason for tracheostomy, method of tracheostomy, and complications.

RESULTS

Of the 1,184 patients who underwent an ACSF, 20 (1.7%) required a postfixation tracheostomy. Tracheostomy was performed at mean (SD) of 6.9 (4.2) days after ACSF, ranging from 0 to 17 days. Although nearly half of all patients underwent postfixation tracheostomy within 6 days, no wound or implant infection was seen to occur in any patient. Ten patients (50%) developed ventilator-associated pneumonia, with most cases occurring before tracheostomy (90% vs. 10%, p < 0.0001). Univariate analysis only revealed late tracheostomy to significantly increase the risk of complications (odds ratio, 9.33; 95% confidence interval, 1.19-73.0; p = 0.033). Analysis of all studies in the literature revealed a 1% cross-infection rate, with no cases involving implant contamination.

CONCLUSION

Our findings suggest that early tracheostomy can be performed safely after cervical spine fixation surgery, with no patients developing incisional or implant infections. As the risk of cross contamination is only 1%, early tracheostomy should be strongly considered because of its potential benefits.

LEVEL OF EVIDENCE

Therapeutic/care management, level IV.

Prevalence of adjacent segment degeneration after spine surgery: a systematic review and meta-analysis

STUDY DESIGN

Systematic review of published prevalence of adjacent segment degeneration (ASD) after spine surgery.

OBJECTIVE

To evaluate the prevalence of ASD in patients after cervical and lumbar spine surgery.

SUMMARY OF BACKGROUND DATA

ASD is a common complication after spine surgery in long-term follow-up. A large body of literature has been reported on the topic, but no meta-analysis of the epidemiological data on ASD has been published

METHODS

We searched the MEDLINE until March 2012 published in English language that reported the prevalence of ASD after spine surgery. We determined the ASD rates by calculating proportions and 95% confidence interval (CI) for each study and then pooled the data to derive a pooled proportion and 95% CI.

RESULTS

A total of 94 studies with 34,716 patients from 19 countries were included. The occurrence of radiograph ASD ranged from 4.8% to 92.2%, and the pooled prevalence was 29.3% (95% CI, 22.7%-35.8%) by the random-effects model. The occurrence of symptoms ASD ranged from 0.0% to 30.3%, and the pooled prevalence was 7.4% (95% CI, 6.4%-8.5%). In cervical position, the occurrence of radiograph ASD and symptoms ASD was 32.8% (95% CI, 17.8%-47.9%) and 6.3% (95% CI, 4.8%-7.8%); in lumbar position, the occurrence of radiograph ASD and symptoms ASD was 26.6% (95% CI, 21.3%-31.9%) and 8.5% (95% CI, 6.4%-10.7%). In the 0.5- to 2- or less, more than 2- to 5- or less, and more than 5- to 20- or less year diagnosis time, the radiograph ASD prevalence was 21.8% (16.0%-27.6%), 33.6% (21.8%-45.4%), and 37.4% (10.7%-64.1%), respectively; and the symptoms ASD prevalence was 6.5% (4.8%-8.1%), 12.1% (8.2%-16.0%), and 3.2% (2.5%-4.0%), respectively.

CONCLUSION

Spine surgery is associated with significant risk of ASD. These figures may be useful in the estimation of the burden of the ASD after spine surgery.

Airway compromise due to wound hematoma following anterior cervical spine surgery

One of the most serious adverse events associated with anterior cervical spine surgery is wound hematoma resulting in airway compromise. The reported incidence of this postoperative complication has varied from 0.2% to 1.9%. Obstruction of the airway secondary to bleeding presents a challenging clinical scenario given the rapidity of onset, distorted anatomy of the upper respiratory tract, urgent need to act and potential for catastrophic consequences. This high-risk, life-threatening clinical scenario requires specialized knowledge and a well-designed treatment protocol to achieve a positive outcome. In this review, we report a case of airway compromise secondary to wound hematoma following anterior cervical discectomy and fusion, followed by a review of relevant literature, anatomy, etiologic factors and diagnostic considerations. We also propose guidelines for the prevention and management of postoperative airway obstruction due to wound hematoma.

Single-level anterior cervical discectomy and interbody fusion using PEEK anatomical cervical cage and allograft bone

BACKGROUND

In an effort to avoid the morbidity associated with autogenous bone graft harvesting, cervical cages in combination with allograft bone are used to achieve fusion. The goal of the current study was to assess the reliability and efficacy of anterior cervical discectomy and interbody fusion (ACDF) using a PEEK anatomical cervical cage in the treatment of patients affected by single-level cervical degenerative disease.

METHODS AND MATERIALS

Twenty-five patients affected by single-level cervical degenerative pathology between C4 and C7 were enrolled in this study. The clinical findings were assessed using the Neck Disability Index and the Visual Analog Scale. Surgical outcomes were rated according to Odom's criteria at last follow-up. Fusion was graded as poor, average, good or excellent by assessing the radiographs. Cervical spine alignment was evaluated by sagittal segmental alignment and sagittal alignment of the whole cervical spine preoperatively, 6 months postoperatively and at the last follow-up.

RESULTS

Twenty-five patients underwent ACDF using a PEEK anatomical cervical cage. All patients had a minimum 2 years of follow-up. The operative levels were C4-C5 in 5 patients, C5-C6 in 12 patients and C6-C7 in 8 patients. Preoperatively, average NDI was 34, 13 at 6 months, and 10 at latest follow-up. The mean preoperative VAS was 7; the mean postoperative VAS at latest follow-up was 3. Good or excellent fusion was achieved in all patients within 10 months (mean 5 months). Preoperatively, average sagittal segmental alignment (SSA) was 0.2° and average sagittal alignment of the cervical spine (SACS) 15.8°. Six months after surgery, average SSA was 1.8° and average SACS 20.9°, and at last follow-up, average SSA was 1.6° and average SACS 18.5°.

CONCLUSION

Anterior cervical discectomy and interbody fusion using PEEK anatomical cervical cages can be considered a safe and effective technique to cure cervical disc herniation with intractable pain or neural deficit in cases where conservative treatment failed.