Cervical Spine Fusion Research Articles

ACDF and posterior spinal fusion revision for posterior nonunion with deformity, myelopathy, and osteoporosis in an 87-year-old: A case report and literature review.

IntroductionCervical spondylotic myelopathy (CSM) is a spinal degenerative disorder that can ultimately lead to compression of the vertebral column with neurological sequelae. Although CSM is the most common spine pathology in the elderly American population, it remains a challenging disorder to treat among older patients.Case presentationWe report an 86 year old female patient with CSM with a history of posterior cervical fusion attempt on C3-C6 that progressed to C3-C6 nonunion with loose instrumentation. The patient had severe osteoporosis. With these indications, the patient underwent a combined anterior-posterior decompression and fusion (CAPDF) consisting of anterior cervical discectomy and fusion (ACDF) of the C3-C5, corpectomy of C6 and C7 with off FDA label use of polymethyl methacrylate augmentation (PMMA) fixation of T1 screws anteriorly for C3-T1 plate fixation and second stage instrumented posterior spinal fusion (PSF) of C3-T3. The patient had a successful fusion and reduction of her cervical spine pain with preservation of her neurological status.DiscussionWe report this case of multi-stage combined anterior and posterior fusion as a corrective measure for pseudarthrosis of a prior posterior cervical spinal fusion attempt.ConclusionIn the event of posterior spinal fusion instrumentation failure in patients with severe osteoporosis, combined multi-stage anterior-posterior fusion is a viable corrective intervention in octogenarians. This case also illustrated the utility of using PMMA for anterior cervical plate and screw stabilization in osteoporotic bone. The authors are not aware of the prior use of PMMA for screw fixation augmentation in the anterior cervical spine.

Bone Graft Erosion into Hypopharynx Presenting with Stridor: Rare Late Complication Following Cervical Spine Surgery.

Cervical bone graft erosion occurs in about 2% of patients as a late complication following cervical spine fusion surgery. The usual presentation in such patients is dysphagia. Stridor is a very rare late complication of such bone erosions. We report a 66-year-old gentleman who presented with stridor, describe the management thereof.

Operative Treatment of Cervical Spine Injuries Sustained in Youth Sports.

Little data exists on surgical outcomes of sports-related cervical spine injuries (CSI) sustained in children and adolescent athletes. This study reviewed demographics, injury characteristics, management, and operative outcomes of severe CSI encountered in youth sports. Children below 18 years with operative sports-related CSI at a Level 1 pediatric trauma center were reviewed (2004 to 2019). All patients underwent morden cervical spine instrumentation and fusion. Clinical, radiographic, and surgical characteristics were analyzed. A total of 3231 patients (mean, 11.3±4.6 y) with neck pain were evaluated for CSI. Sports/recreational activities were the most common etiology in 1358 cases (42.0%). Twenty-nine patients (2.1%) with sports-related CSI (mean age, 14.5 y; range, 6.4 to 17.8 y) required surgical intervention. Twenty-five were males (86%). Operative CSI occurred in football (n=8), wrestling (n=7), gymnastics (n=5), diving (n=4), trampoline (n=2), hockey (n=1), snowboarding (n=1), and biking (n=1). Mechanisms were 27 hyperflexion/axial loading (93%) and 2 hyperextension injuries (7%). Most were cervical fractures (79%) and subaxial injuries (79%). Seven patients (24%) sustained spinal cord injury (SCI) and 3 patients (10%) cord contusion or myelomalacia without neurological deficits. The risk of SCI increased with age (P=0.03). Postoperatively, 2 SCI patients (29%) improved 1 American Spinal Injury Association Impairment Scale Grade and 1 (14%) improved 2 American Spinal Injury Association Impairment Scale Grades. Increased complications developed in SCI than non-SCI cases (mean, 2.0 vs. 0.1 complications; P=0.02). Bony fusion occurred in 26/28 patients (93%) after a median of 7.2 months (interquartile range, 6 to 15 mo). Ten patients (34%) returned to their baseline sport and 9 (31%) to lower-level activities. The incidence of sports-related CSI requiring surgery is low with differences in age/sex, sport, and injury patterns. Older males with hyperflexion/axial loading injuries in contact sports were at greatest risk of SCI, complications, and permanent disability. Prevention campaigns, education on proper tackling techniques, and neck strength training are required in sports at high risk of hyperflexion/axial loading injury. Level III-retrospective cohort study.

Retro-odontoid pseudotumor concomitant with proximal adjacent cervical spondylotic myelopathy after multilevel anterior cervical discectomy and fusion.

Introduction and importanceAdjacent cervical spondylotic myelopathy (CSM) following anterior cervical discectomy and fusion (ACDF) presenting as a retro-odontoid pseudotumor (ROP) is uncommon. This consequence adversely affects hand function, causes gait imbalance and results in other disabilities for the patient. This report describes the successful surgical treatment of a patient with ROP associated with adjacent CSM following multilevel ACDF of the subaxial cervical vertebrae by performing posterior cervical decompression and fusion.Case presentationA 60-year-old-male presented with progressive, disabling cervical myelopathy. He had undergone ACDF C3-C7 for treatment of CSM 16 years ago and his symptoms had fully resolved. Magnetic resonance imaging (MRI) revealed severe cervical spinal cord compression caused by a retro-odontoid mass at the C1-C2 level with upper adjacent segment disease (ASD) of C1-C3. The patient received C1-C3 posterior cervical spinal fusion by C1 lateral mass C2 and C3 pedicle screw fixation and C1-C3 laminectomy. After the surgery, he was able to ambulate independently and the myelopathic symptoms were significantly improved at the 6 months follow-up.Clinical discussionRetro-odontoid pseudotumor concomitant with proximal ASD following ACDF is a rare occurrence. Both diagnosis and surgical management are challenging.ConclusionsPosterior cervical decompression and fusion of C1-C3 is an effective option for treatment of severe cervical spinal cord compression by a retro-odontoid mass at the C1-C2 level combined with ASD after ACDF.

Machine learning-driven identification of novel patient factors for prediction of major complications after posterior cervical spinal fusion.

Posterior cervical fusion is associated with increased rates of complications and readmission when compared to anterior fusion. Machine learning (ML) models for risk stratification of patients undergoing posterior cervical fusion remain limited. We aim to develop a novel ensemble ML algorithm for prediction of major perioperative complications and readmission after posterior cervical fusion and identify factors important to model performance. This is a retrospective cohort study of adults who underwent posterior cervical fusion at non-federal California hospitals between 2015 and 2017. The primary outcome was readmission or major complication. We developed an ensemble model predicting complication risk using an automated ML framework. We compared performance with standard ML models and logistic regression (LR), ranking contribution of included variables to model performance. Of the included 6822 patients, 18.8% suffered a major complication or readmission. The ensemble model demonstrated slightly superior predictive performance compared to LR and standard ML models. The most important features to performance include sex, malignancy, pneumonia, stroke, and teaching hospital status. Seven of the ten most important features for the ensemble model were markedly less important for LR. We report an ensemble ML model for prediction of major complications and readmission after posterior cervical fusion with a modest risk prediction advantage compared to LR and benchmark ML models. Notably, the features most important to the ensemble are markedly different from those for LR, suggesting that advanced ML methods may identify novel prognostic factors for adverse outcomes after posterior cervical fusion.

Posterior Floating Laminotomy as a New Decompression Technique for Posterior Cervical Spinal Fusion Surgery.

ObjectiveIn the cervical spine, many surgical procedures have been developed to achieve optimal results for various disorders, including degenerative diseases, traumatic injury, and tumor. In this study, we report our experience and follow-up results with a new surgical technique for cervical spine entitled posterior floating laminotomy (PFL) in comparison with conventional laminectomy and fusion (LF). MethodsData for 85 patients who underwent conventional LF (n=66) or PFL (n=19) for cervical spine disorders between 2012 and 2019 were analyzed. Radiological parameters, including cervical lordosis (CL), T1 slope (T1S), segmental lordosis (SL), and C2–7 sagittal vertical axis (SVA), were measured with lateral spine X-rays. Functional outcomes, comprising the modified Japanese Orthopaedic Association (mJOA), neck disability index (NDI), and visual analog scale (VAS) scores, were also measured. For the patients who underwent PFL, postoperative magnetic resonance image (MRI) was performed in a month after the surgery, and the degree of decompression was evaluated at the T2-weighted axial image, and postoperative computed tomography (CT) was conducted immediately and 1 year after the operation to evaluate the gutter fusion. ResultsThere was no difference in CL, T1S, SL, and C2–7 SVA between the groups but there was a difference in the preoperative and postoperative SL angles. The mean difference in the preoperative SL angle compared with that at the last follow-up was -0.3° after conventional LF and 4.7° after PFL (p=0.04), respectively. mJOA, NDI, and VAS scores showed significant improvements (p<0.05) during follow-up in both groups. In the PFL group, postoperative MRI showed sufficient decompression and postoperative CT revealed gutter fusion at 1 year after the operation. ConclusionPFL is a safe surgical method which can preserve postoperative CL and achieve good clinical outcomes.

P126. Development of a novel ensemble machine learning algorithm for prediction of complications and readmission after posterior cervical spinal fusion

<h3>BACKGROUND CONTEXT</h3> Cervical spinal fusion is one of the most commonly performed surgeries in the United States and is rapidly growing in prevalence. The average age and comorbidity burden of patients undergoing cervical fusion has also increased, elevating the risk of perioperative complications and unplanned readmissions. Given the cost and morbidity associated with these poor outcomes, accurate preoperative risk stratification is of great utility. Advanced machine learning (ML) methods have become increasingly employed in spinal surgery due to their ability to recognize complex, non-linear relationships between variables. ML models for preoperative risk stratification of patients undergoing posterior cervical fusion remain limited. <h3>PURPOSE</h3> We aim to develop a novel ensemble ML algorithm for prediction of major perioperative complication and unplanned readmission after posterior cervical fusion. Our secondary aim is to compare its performance against benchmark ML models and logistic regression (LR). <h3>STUDY DESIGN/SETTING</h3> Retrospective, cohort study. <h3>PATIENT SAMPLE</h3> Patients 18 years or older at a non-federal California hospital who underwent posterior cervical spinal fusion. <h3>OUTCOME MEASURES</h3> Readmission within 30 days, major perioperative complications (venous thromboembolism within 30 days, myocardial infarction within 7 days, pneumonia within 7 days, systemic infection within 7 days, surgical site bleeding within 90 days, and wound complications within 90 days). <h3>METHODS</h3> This is a retrospective cohort study of adult patients who underwent instrumented or non-instrumented posterior cervical spinal fusion at any California hospital between 2015-2017. We developed a ML-based model predicting complication risk using AutoPrognosis, an automated ML framework that configures the optimally performing ensemble of ML-based prognostic models. We compared our model with LR and four standard ML models (XGBoost, Gradient Boosting, AdaBoost, Random Forest). Predictive performances were assessed using area under the receiver operating characteristic curve (AUROC). We ranked the contribution of the included variables to model performance. <h3>RESULTS</h3> Of the 6,822 patients who met inclusion criteria, there were 1,279 cases of at least one major complication or readmission (18.8%). The ensemble AutoPrognosis model had superior risk prediction (AUROC: 0.679 + 0.011) compared to LR (0.651 + 0.014). Furthermore, this model outperformed the four benchmark ML algorithms. The variables most important for AutoPrognosis include history of malignancy, number of comorbidities, and hospital volume. Five of the 10 most important features for AutoPrognosis were markedly less important for LR: teaching hospital status, implant complications, pneumonia, stroke and chronic kidney disease. <h3>CONCLUSIONS</h3> We report the use of a novel ensemble ML algorithm for prediction of major perioperative complications after posterior cervical fusion. Our novel AutoPrognosis algorithm is well-calibrated and outperforms LR and four standard ML algorithms. By automating the choice of appropriate model as well as tuning of model hyperparameters, AutoPrognosis can be used by clinicians who may not possess an in-depth knowledge of ML methods – facilitating the use of advanced ML methods in mainstream clinical research. Notably, the predictors most important for AutoPrognosis are different from those for LR. This suggests that the superior discriminative capability of AutoPrognosis results from not just its ability to select among different ML models but also by capturing complex non-linear relationships between variables that logistic regression is unable to capture. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

262. Does preoperative bone mineral density impact fusion success in anterior cervical spine surgery: a prospective cohort study

<h3>BACKGROUND CONTEXT</h3> Patients with osteoporosis have an imbalance in anabolic versus catabolic bone homeostasis. It has been theorized that osteoporosis may impact fusion rates in lumbar spine surgery. However, to our knowledge this has not been investigated in cervical spine surgery. As our population ages, we are encountering ever increasing numbers of patients with osteoporosis and osteopenia coming in for elective surgery. <h3>PURPOSE</h3> The purpose of this study is to identify risk factors for pseudarthrosis in patients undergoing anterior cervical spine surgery. <h3>STUDY DESIGN/SETTING</h3> This was a prospective, single-center study conducted at an academic medical center between 2002 and 2018. <h3>PATIENT SAMPLE</h3> Seventy-nine patients who underwent 1-4 level anterior cervical spine fusions between the years of 2002-2018, and had a bone mineral density examination performed preoperatively, completed the study with one year of clinical and radiographic follow-up. <h3>OUTCOME MEASURES</h3> Bone density as measured by T-score, Hounsfield units and fusion status were measured. <h3>METHODS</h3> We prospectively collected and analyzed data on patients undergoing anterior cervical spine fusions involving between 1-4 levels between the years of 2002-2018 in which a bone mineral density (BMD) examination was clinically indicated. Based on the World Health Organization (WHO) classification using DEXA scan for measurement of BMD, normal bone density was defined as T-score greater than or equal to -1 SD, osteopenia as having a T-score less than -1 and greater than -2.5 SD, and osteoporosis as having a T-score less than or equal to -2.5 SD. Patients were followed for a minimum of one year. CT scans performed postoperatively were used to evaluate fusion. Three Hounsfield unit measurements were obtained on the vertebrae above and below the fusion levels and averaged. A total of 79 patients completed the study with one-year of clinical and radiographic follow-up. BMD, number of levels fused, smoking status, age, sex and ACE inhibitors/ARBs were analyzed to assess their impact on fusion success. Fusion was established when there was continuous bone bridging between the vertebrae on CT scan. Multivariate analysis was performed to identify potential risk factors for pseudarthrosis utilizing JMP 10.0.0 statistical software. (SAS Institute Inc, Carey, North Carolina). <h3>RESULTS</h3> Fourteen patients (18%) developed pseudarthrosis at one-year postoperatively. The mean age at surgery was 58.8 ±10.5 (30 to 84 years). The mean BMD was -0.45 ±1.4 (-3 to 4). Osteopenia and osteoporosis were identified as risk factors for pseudarthorsis at a minimum of 1 year follow up. Number of levels fused, smoking status, Hounsfield units, ACE/ARB medications, age or gender were not statistically significant risk factors correlated with development of pseudarthrosis although the study may have been underpowered to detect these differences. <h3>CONCLUSIONS</h3> This study suggests that preoperative osteopenia or osteoporosis may be correlated with a higher incidence of pseudarthrosis in anterior cervical spine surgery, even more so than smoking or number of levels fused. While the number of patients enrolled in this study is small, the results are convincing enough to warrant screening and treatment of osteoporosis as well as the optimization of preoperative bone stock in all potential candidates for cervical spine fusion. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

P125. Development of a novel ensemble machine learning algorithm for prediction of complications and readmission after anterior cervical spinal fusion

<h3>BACKGROUND CONTEXT</h3> Anterior cervical spinal fusion procedures have grown in prevalence due to excellent outcomes, low risk of perioperative outcomes and reduced length of hospitalization. The average age and comorbidity burden of patients undergoing anterior cervical fusion has increased. Given the significant cost and morbidity associated with developing major perioperative complications and unplanned readmissions, accurate risk stratification of patients undergoing this procedure is of great utility. Advanced machine learning (ML) methods have become increasingly employed in spinal surgery due to their ability to recognize complex, non-linear relationships between variables. ML models for preoperative risk stratification of patients undergoing anterior cervical fusion remain limited. <h3>PURPOSE</h3> We aim to develop a novel ensemble ML algorithm for prediction of major perioperative complication and readmission after anterior cervical fusion. Our secondary aim is to compare its performance against benchmark ML models and logistic regression (LR). <h3>STUDY DESIGN/SETTING</h3> Retrospective, cohort study. <h3>PATIENT SAMPLE</h3> Patients 18 years or older at a non-federal California hospital who underwent anterior cervical spinal fusion. <h3>OUTCOME MEASURES</h3> Readmission within 30 days, major perioperative complications (venous thromboembolism within 30 days, myocardial infarction within 7 days, pneumonia within 7 days, systemic infection within 7 days, surgical site bleeding within 90 days, and wound complications within 90 days). <h3>METHODS</h3> This is a retrospective cohort study of adult patients who underwent anterior cervical fusion at any California hospital between 2015-2017. We developed a ML-based model predicting complication risk using AutoPrognosis, an automated ML framework that configures an optimally performing ensemble of ML-based prognostic models. We compared our model with LR and four standard ML models (XGBoost, Gradient Boosting, AdaBoost, Random Forest). Predictive performances were assessed using area under the receiver operating characteristic curve (AUROC). Calibration was assessed using Brier scores. We ranked the contribution of the included features to model performance. <h3>RESULTS</h3> Of the 23,184 patients who met inclusion criteria, there were 1,886 cases of major complication or readmission (8.13%). The ensemble AutoPrognosis model had superior risk prediction (AUROC 0.724 + 0.015) compared to LR (0.717 + 0.012). Furthermore, our model outperformed the four standard ML algorithms. The AutoPrognosis model was well-calibrated (Brier score 0.069 + 0.01). The variables that are most important for AutoPrognosis include patient sex, workers' compensation insurance, age, malnutrition, and chronic obstructive pulmonary disease. Teaching hospital status, schizophrenia, and quadriplegia are also among the 10 most important features for AutoPrognosis model performance but not for LR. <h3>CONCLUSIONS</h3> We report the use of a novel ensemble ML algorithm for prediction of major perioperative complications after anterior cervical fusion. This algorithm is well-calibrated and demonstrates excellent risk prediction, superior to LR and four standard ML algorithms. By automating the choice of appropriate model as well as tuning of model hyperparameters, AutoPrognosis can be used by clinicians who may not possess an in-depth knowledge of ML methods – facilitating the use of advanced ML methods in mainstream clinical research. Notably, the predictors most important for AutoPrognosis are different from those for LR. This suggests that the superior discriminative capability of AutoPrognosis results from not just its ability to select among different ML models but also by capturing complex non-linear relationships between variables that LR is unable to capture. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Operative Treatment of Severe Cervical Spine Injuries Sustained in Youth Sports: Experience from a Pediatric Level 1 Trauma Center over a 16-Year Period

Background:Sports-related cervical spine injuries (CSI) are devastating traumas with the potential for permanent disability. There is a paucity of literature on operative CSI sustained in youth athletes.Hypothesis/Purpose:The aims of this study aims were to review injury characteristics, surgical treatment, and outcomes of severe pediatric CSI encountered in youth sports.Methods:We reviewed children less than 18 years old with operative sports-related CSI at a pediatric Level 1 pediatric trauma center between 2004−2019. All cases underwent modern cervical spine instrumentation and fusion. SCI were stratified according to the American Spinal Injury Association Impairment Scale (ASIA). Clinical, radiographic, and surgical characteristics were compared between groups of patients with and without spinal cord injury (SCI).Results:Three thousand two hundred and thirty-one children (mean, 11.3y±4.6y) were evaluated for CSI at our institution during the 16-year period. The majority of traumas resulted from sports/recreational activities and were seen in 1365 cases (42.3%). Of these, 171/1365 patients (12.5%) were admitted and 29/1365 patients (2.1%) required surgical intervention (mean age, 14.5y±2.88y; range, 6.4y–17.8y). Sports included: eight football (28%), seven wrestling (24%), five gymnastics (17%), four diving (14%), two trampoline (7%), one hockey (3%), one snowboarding (3%), and one biking injury (3%). Mechanisms were 19 hyperflexion (65%), eight axial loading (28%), and two hyperextension injuries (7%). The majority of operative CSI were fractures (79%) and/or subaxial defects (72%). Seven patients (30%) sustained SCI and three patients (10%) spinal cord contusion or myelomalacia without neurologic deficits. The risk of SCI increased with age (15.8y vs. 14.4y; p=0.03) and axial loading mechanism (71% vs. 14%; p=0.003).Postoperatively, two SCI patients (29%) improved 1 ASIA Grade and one (14%) improved 2 ASIA Grades. Increased complications developed in SCI than patients without SCI (mean, 2.0 vs 0.1 complications; p=0.02). Clinical and radiographic fusion occurred in 24/26 patients (92%) with adequate follow-up (median, 32 months). Ten patients returned to their previous activity and nine to sports with a lower level of activity.Conclusion:The overall incidence of sports-related operative CSI is low. Age- and gender discrepancies exist, with male adolescent athletes most commonly requiring surgery. Hyperflexion injuries had a good prognosis; however, older males with axial loading CSI sustained in contact sports were at greatest risk of SCI, complications, and permanent disability.Figure 1.1:Etiology of all cervical spine injuries between 2004-2019

Fusion Rates with Autologous Bone Grafts in Pediatric Patients Undergoing Posterior Cervical Spine Fusion

Fusion Rates with Autologous Bone Grafts in Pediatric Patients Undergoing Posterior Cervical Spine Fusion

Effects of focused continuous pulsed electromagnetic field therapy on early tendon-to-bone healing.

AimsRotator cuff (RC) tears are common musculoskeletal injuries which often require surgical intervention. Noninvasive pulsed electromagnetic field (PEMF) devices have been approved for treatment of long-bone fracture nonunions and as an adjunct to lumbar and cervical spine fusion surgery. This study aimed to assess the effect of continuous PEMF on postoperative RC healing in a rat RC repair model.MethodsA total of 30 Wistar rats underwent acute bilateral supraspinatus tear and repair. A miniaturized electromagnetic device (MED) was implanted at the right shoulder and generated focused PEMF therapy. The animals’ left shoulders served as controls. Biomechanical, histological, and bone properties were assessed at three and six weeks.ResultsExtension of the tendon from preload to the maximum load to failure was significantly better in the PEMF-treated shoulders at three weeks compared to controls (p = 0.038). The percentage strain was significantly higher in the PEMF group at both timepoints (p = 0.037). Collagen organization was significantly better (p = 0.034) as was tissue mineral density in the PEMF-treated group at three weeks (p = 0.028). Tendon immunohistochemistry revealed a prominent increase in type I collagen at the repair site at three weeks following continuous PEMF treatment compared with controls. None of the other tested parameters differed between the groups.ConclusionMED-generated PEMF may enhance early postoperative tendon-to-bone healing in an acute rat supraspinatus detachment and repair model. Superior biomechanical elasticity parameters together with better collagen organization suggest improved RC healing.Cite this article: Bone Joint Res 2021;10(5):298–306.

Diagnosis of reoperated cervical non-union: Multicenter retrospective study about 45 patients

IntroductionNon-union is one of the main complications of single- or multi-level cervical spine fusion, considerably impairing functional results. The aim of this study was to evaluate the respective contributions of imaging examinations in the diagnostic process, the challenge being to avoid inappropriate surgery and unnecessary complementary examinations. Material and methodA retrospective multicenter study included all patients managed for cervical spine non-union between 2008 and 2018. We evaluated the imaging examinations performed on each patient and determined signs of non-union in each image. ResultsThe study included 45 patients in 4 centers: 55% female; mean age, of 48±8.0 years; 57% smokers. Systematic static radiography showed signs of non-union in 55% of cases. Dynamic X-ray was performed in 34% of patients, and showed hypermobility of the level in 80% of cases. CT supported diagnosis of non-union in 97% of cases, and MRI in 48%. SPECT-CT was positive in all cases of non-union. DiscussionDynamic X-ray is rarely prescribed, but frequently provided an objective measure of hypermobility of the level in non-union, justifying first-line use. Millimetric-slice CT was reliable for diagnosis. MRI is relevant only once diagnosis has been made, as part of preoperative work-up. Nuclear imaging can be useful in order to solve doubtful cases. ConclusionIn suspected cervical spine non-union, we recommend dynamic X-rays (flexion/extension) and CT-scan as first-line diagnosis examinations. Level of evidenceIV.

Recurrent cerebellar infarction due to vertebral artery dissection in an athetotic patient

AbstractA 42‐year‐old man with longstanding athetotic‐type cerebral palsy and history of cervical spine fusion surgery was affected by multiple episodes of vertebral artery dissections, resulting in bilateral cerebellar infarction. Continuous involuntary movements noted in the upper limbs and neck, as well as a limited cervical range of motion due to the operation might have precipitated the dissecting events.

Vacuum plasma sprayed porous titanium coating on polyetheretherketone for ACDF improves the osteogenic ability: An in vitro and in vivo study.

Cervical degenerative disease is a common and frequently occurring disease, which seriously affects the health and quality of the life of patients worldwide. Anterior cervical decompression and interbody fusion is currently recognized as the gold standard for the treatment of degenerative cervical spondylosis. Polyetheretherketone (PEEK) has become the prevailing material for cervical fusion surgery. Although PEEK has excellent biocompatibility, it is difficult to form bone connection at its bone-implant interface due to its low surface hydrophilicity and conductivity. It is widely accepted that Ti has excellent osteogenic activity and biocompatibility. In this study, a Ti-PEEK composite cage was prepared by coating Ti on the surface of a PEEK cage using a vacuum plasma spraying technique to enhance the osteogenic property of PEEK. The Ti-PEEK samples were evaluated in terms of their in vitro cellular behaviors and in vivo osteointegration, and the results were compared to a pure PEEK substrate. The skeleton staining and MTS assay indicated that the MC3T3-E1 cells spread and grew well on the surface of Ti-PEEK cages. The osteogenic gene expression and western blot analysis of osteogenic protein showed upregulated bone-forming activity of MC3T3-E1 cells in Ti-PEEK cages. Furthermore, a significant increase in new bone formation was demonstrated on Ti-PEEK implants in comparison with PEEK implants at 12weeks in a sheep cervical spine fusion test. These results proved that the Ti-PEEK cage exhibited enhanced osseointegrative properties compared to the PEEK cage both in vitro and in vivo.

Vascularized Bone Grafts for Spinal Fusion-Part 3: The Occiput.

Obtaining successful arthrodesis at the craniocervical junction and atlantoaxial joint can be more challenging than in other segments of the cervical spine. This challenge stems from the relatively hypermobile joints between the occipital condyles, the motion that occurs at C1 and C2, as well as the paucity of dorsal bony surfaces for posterior arthrodesis. While multiple different techniques for spinal fixation in this region have been well described, there has been little investigation into auxiliary methods to improve fusion rates. To describe the use of an occipital bone graft to augment bony arthrodesis in the supraaxial cervical spine using a multidisciplinary approach. We review the technique for harvesting and placing a vascularized occipital bone graft in 2 patients undergoing revision surgery at the craniocervical junction. The differentiation from nonvascularized bone graft, either allograft or autograft, to a bone graft using vascularized tissue is a key principle of this technique. It has been well established that vascularized bone heals and fuses in the spine better than structural autogenous grafts. However, the morbidity and added operative time of harvesting a vascularized flap, such as from the fibula or rib, precludes its utility in most degenerative spine surgeries. By adapting the standard neurosurgical procedure for a suboccipital craniectomy and utilizing the tenets of flap-based reconstructive surgery to maintain the periosteal and muscular blood supply, we describe the feasibility of using a vascularized and pedicled occipital bone graft to augment instrumented upper cervical spinal fusion. The use of this vascularized bone graft may increase fusion rates in complex spine surgeries.

Perioperative Corticosteroids Reduce Dysphagia Severity Following Anterior Cervical Spinal Fusion: A Meta-Analysis of Randomized Controlled Trials.

The anterior approach to the cervical spine is commonly used to treat cervical pathology. It is, however, associated with high rates of dysphagia, which may be associated with substantial patient morbidity. Perioperative corticosteroid administration has been advocated to decrease dysphagia rates; its efficacy, however, remains uncertain. We conducted a meta-analysis of randomized trials to determine the efficacy of perioperative corticosteroid administration in reducing postoperative dysphagia as well as any adverse effects, such as pseudarthrosis and infection. We conducted a systematic search of electronic databases (MEDLINE, Embase, CENTRAL [Cochrane Central Register of Controlled Trials], ClinicalTrials.gov) to identify randomized controlled trials (RCTs) that evaluated corticosteroids versus any comparator for prevention of postoperative dysphagia after anterior cervical spine procedures. Two independent reviewers used the GRADE (Grades of Recommendation Assessment, Development and Evaluation) criteria to assess eligibility and risk of bias, perform data extraction, and rate the quality of evidence. The primary outcome was severity of postoperative dysphagia. We conducted meta-analyses of dysphagia (both overall and by delivery method), pseudarthrosis, and postoperative infection. After screening of 927 articles, a total of 7 studies were eligible for final inclusion. These included 431 patients, of whom 247 received corticosteroids and 184 received placebo or a control treatment. Moderate-quality evidence demonstrated a significant improvement in postoperative dysphagia rates (odds ratio, 0.35; 95% confidence interval, 0.20 to 0.63; p < 0.001), and this finding was robust to both permutation analyses and sensitivity analyses removing the studies with a high risk of bias. There was no significant difference between intravenous and local steroid administration (p = 0.16). There were no documented infections. There was no significantly increased risk of pseudarthrosis in those receiving steroids compared with placebo or a control treatment (p = 0.13). This meta-analysis found moderate-quality evidence supporting the use of perioperative corticosteroid administration as an adjunct to anterior cervical spinal procedures. Patients treated with corticosteroids intravenously or locally had significantly decreased severity of dysphagia. Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Failure in Cervical Spinal Fusion and Current Management Modalities

Failed fusion in the cervical spine is a multifactorial problem stemming from a combination of patient and surgical factors. Patient-related risk factors such as steroid use, poor bone quality, and smoking can be optimized preoperatively. Age, prior radiation, prior surgery, and underlying genetics are nonmodifiable patient-centered risk factors. Surgical risks for failed fusion include the number of segments fused, anterior versus posterior approach for fusion, the type of bone graft, and the instrumentation utilized. Many symptomatic cases of failed fusion (pseudarthrosis) result in pain, neurological deficits, or loosened hardware necessitating a revision surgery consisting of extending the prior construct and utilizing additional allografts or autografts to augment the fusion. Given the relatively mobile nature of the cervical spine, pseudoarthrosis (either known or anticipated) must be recognized by the spine surgeon, and steps should be considered to optimize the likelihood of future fusion. This consists of both performing a rigid fixation and using appropriate bone graft to enhance the environment for arthrodesis. Vascularized bone grafts are a useful tool to augment fusion and provide added structural stability in cases at high risk of pseudoarthrosis.

Prospective phenotyping of long-term survivors of generalized arterial calcification of infancy (GACI)

PurposeGeneralized arterial calcification of infancy (GACI), characterized by vascular calcifications that are often fatal shortly after birth, is usually caused by deficiency of ENPP1. A small fraction of GACI cases result from deficiency of ABCC6, a membrane transporter. The natural history of GACI survivors has not been established in a prospective fashion. MethodsWe performed deep phenotyping of 20 GACI survivors. ResultsSixteen of 20 subjects presented with arterial calcifications, but only 5 had residual involvement at the time of evaluation. Individuals with ENPP1 deficiency either had hypophosphatemic rickets or were predicted to develop it by 14 years of age; 14/16 had elevated intact FGF23 levels (iFGF23). Blood phosphate levels correlated inversely with iFGF23. For ENPP1-deficient individuals, the lifetime risk of cervical spine fusion was 25%, that of hearing loss was 75%, and the main morbidity in adults was related to enthesis calcification. Four ENPP1-deficient individuals manifested classic skin or retinal findings of PXE. We estimated the minimal incidence of ENPP1 deficiency at ~1 in 200,000 pregnancies. ConclusionGACI appears to be more common than previously thought, with an expanding spectrum of overlapping phenotypes. The relationships among decreased ENPP1, increased iFGF23, and rickets could inform future therapies.

Crossing the Cervico-Thoracic Junction in Long Posterior Cervical Fusions Reduces Caudal Adjacent Segment Pathology.

Study Design:Retrospective case control.Objectives:The purpose of this study is to compare clinical outcomes and rates of symptomatic caudal adjacent segment pathology (ASP) in posterior cervical fusions (PCF) constructs with end-instrumented vertebrae in the cervical spine (EIV-C) to PCF constructs that end in the proximal thoracic spine (EIV-T).Methods:Retrospective review of 1714 consecutive cervical spinal fusion cases was done. Two groups were identified: 36 cervical end-instrumented vertebra patients (age56 ± 10 yrs) and 53 thoracic EIV patients (age 57 ± 9 yrs). Symptomatic ASP was defined as revision surgery or nerve root injection (or recommended surgery or injection) at the adjacent levels.Results:EIV-C patients had a significantly higher rate of caudal-level symptomatic ASP requiring intervention compared with EIV-T patients (39% vs 15%, p = 0.01). The development of caudal-level ASP was highest at C7 (41%), followed by C6 (40%). The overall complication rate and surgical revision rates, however, were similar between the groups. Neck Disability Index outcomes at 2 years postop were significantly better in the EIV-T group (24.5 vs. 34.0, p = 0.05).Conclusions:Long PCF that cross the C-T junction have superior clinical outcomes and reduced rates of caudal breakdown, at the expense of longer fusions and higher EBL, with no increase in the rate of complications. Crossing the C-T junction affords protection of the caudal adjacent levels without adding significant operative time or morbidity.