The Role of Osteobiologics in Augmenting Spine Fusion in Unplated Anterior Cervical Discectomy and Fusion Compared to Plated Constructs: A Systematic Review and Meta-analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: To compare clinical and radiographic outcomes as well as complications of unplated vs plated anterior cervical discectomy and fusion (ACDF) surgery considering the role of osteobiologics in single- and multi-level procedures. METHODS: A systematic search of PubMed/MEDLINE, Scopus, CINAHL, EMBASE, CENTRAL, Cochrane and ClinicalTrials.gov databases was performed. Briefly, we sought to identify studies comparing unplated vs. plated ACDF for cervical degenerative disc disease reporting the use of osteobiologics in terms of clinical outcomes, radiographic fusion, and complications. Data on study population, follow-up time, type of cage and plate used, type of osteobiologic employed, number of levels treated, patient-reported outcomes (PROs), radiographic outcomes and complications were collected and compared. Relevant information was pooled for meta-analyses. RESULTS: Thirty-eight studies met the inclusion criteria. No significant difference was found in terms of clinical outcomes between groups. Unplated ACDF was characterized by reduced blood loss, operation time and length of hospital stay. Fusion was achieved by the majority of patients in both groups, with no evidence of any specific contribution depending on the osteobiologics used. Dysphagia was more commonly associated with anterior plating, while cage subsidence prevailed in the unplated group. CONCLUSION: Unplated and plated ACDF seem to provide similar outcomes irrespective of the osteobiologic used, with minor differences with doubtful clinical significance. However, the heterogeneity and high risk of bias affecting included studies markedly prevent significant conclusions.

Structural Allograft Versus Mechanical Interbody Devices Augmented With Osteobiologics in Anterior Cervical Discectomy and Fusion: A Systematic Review.

STUDY DESIGN: Systematic Literature Review. OBJECTIVE: Perform a systematic review evaluating postoperative fusion rates for anterior cervical discectomy and fusion (ACDF) using structural allograft vs various interbody devices augmented with different osteobiologic materials. METHODS: Comprehensive literature search using PubMed, Embase, The Cochrane Library, and Web of Science was performed. Included studies were those that reported results of 1-4 levels ACDF using pure structural allograft compared with a mechanical interbody device augmented with an osteobiologic. Excluded studies were those that reported on ACDF with cervical corpectomy; anterior and posterior cervical fusions; circumferential (360° or 540°) fusion or revision ACDF for nonunion or other conditions. Risk of bias was determined using the Cochrane review guidelines. RESULTS: 8 articles reporting fusion rates of structural allograft and an interbody device/osteobiologic pair were included. All included studies compared fusion rates following ACDF among structural allograft vs non-allograft interbody device/osteobiologic pairs. Fusion rates were reported between 84% and 100% for structural allograft, while fusion rates for various interbody device/osteobiologic combinations ranged from 26% to 100%. Among non-allograft cage groups fusion rates varied from 73-100%. One study found PEEK cages filled with combinations of autograft, allograft, and demineralized bone matrix (DBM) to have an overall fusion rate of 26%. In one study comparing plate and zero-profile constructs, there was no difference in fusion rates for two-level fusions. CONCLUSION: There was limited data comparing fusion outcomes of patients undergoing ACDF using structural allograft vs interbody devices augmented with osteobiologic materials to support superiority of one method.

Top 100 Cited Articles on Spinal Disc Arthroplasty Research.

STUDY DESIGN: A bibliometric review of current literature. OBJECTIVE: The purpose of this study was to identify and analyze the 100 most cited articles in spinal disc arthroplasty (SDA) research. SUMMARY OF BACKGROUND DATA: In the last several decades, SDA has been widely performed all over the world, with increasing popularity of cervical disc arthroplasty (CDA). While there is a large number of articles on this topic, to our knowledge, there is no bibliometric analysis yet. METHODS: All databases from the Web of Science were searched in a three-step approach. The information of the 100 most cited studies was collected, including title, first and last author, year of publication, journal, total citations, geographic origin, subspecialty, and types of artificial intervertebral disc for further analysis. RESULTS: The 100 most-cited articles were published from 1966 to 2015 in 9 different journals and were cited from 66 to 346 times. A total of 11 countries contributed to the 100 articles and the United States topped the list, with 54 articles, followed by Germany and France, with 10 and nine articles, respectively. There were more studies in CDA (n = 53) than lumbar disc arthroplasty (n = 35). Most of the studies reported clinical and radiographic outcomes (n = 33). The most productive periods were from 2006 to 2010. The majority of publications were in Spine, which published 43 articles. In total, 12 authors published more than two articles on the list. CONCLUSION: Of the top 100 most cited articles on SDA, cervical papers outnumbered lumbar articles and the United States had 55 articles, with no other countries having more than 10. Our paper can help readers determine which of the thousands of articles on this topic are the most impactful and important ones to be familiar with. LEVEL OF EVIDENCE: 3.

Mid-Term to Long-Term Outcomes After Total Cervical Disk Arthroplasty Compared With Anterior Diskectomy and Fusion: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

STUDY DESIGN: This study was a meta-analysis of published randomized controlled trials (RCTs). OBJECTIVE: We investigated the mid-term to long-term outcomes of cervical disk arthroplasty (CDA) versus anterior cervical diskectomy and fusion (ACDF) for the surgical treatment of symptomatic cervical disk degenerative disease. SUMMARY OF BACKGROUND DATA: ACDF has been widely performed for the surgical treatment of symptomatic cervical disk degenerative disease. However, the loss of motion at the operated level has been hypothesized to accelerate adjacent-level disk degeneration. CDA was designed to preserve motion segments and decrease the risk/rate of adjacent segment degeneration. However, it is still uncertain whether mid-term to long-term outcomes after CDA is more effective and safer than those observed after ACDF. METHODS: Two independent reviewers conducted a search of PubMed, Embase, and the Cochrane Library databases for RCTs with a minimum of 48 months of follow-up. For dichotomous variables, the risk ratio and 95% confidence intervals were calculated. For continuous variables, the standardized mean difference and 95% confidence intervals were calculated. RESULTS: Eleven RCTs, finally, were included. The rate of neurological success in the CDA group was not significantly different from that in the ACDF group. The pooled results show that patients who underwent CDA had a significantly greater improvement in Neck Disability Index (NDI) and Short Form 36 Health Survey physical component (SF-36 HSPC) than did those who underwent ACDF. No significant difference was found when comparing the neck and arm pain scores between the CDA and ACDF groups. The overall rate of secondary surgical procedures was significantly lower in patients who underwent CDA than in those who underwent ACDF. We observed similar overall rates of adverse events and adjacent segment degeneration when comparing the CDA group with the ACDF group. CONCLUSIONS: This meta-analysis provides evidence suggesting that CDA was superior to ACDF in terms of NDI score, SF-36 HSPC score, and low rate of secondary surgical procedures. Furthermore, no significant differences existed between the CDA group and the ACDF group in the neck pain visual analog scale score, arm pain visual analog scale score, the rate of neurological success, adjacent segment degeneration, and adverse events. LEVEL OF EVIDENCE: Level 1.

Effect of an intensive conservative therapy with daily teriparatide administration and rehabilitation for osteoporotic delayed vertebral collapse and paralysis.

Although patients with osteoporotic delayed vertebral collapse (ODVC) have frequently been treated surgically, the efficacy and limitation of conservative treatment for it have not yet been reported. The purpose of this study was to investigate the effectiveness and limitation of further intensive conservative treatment for patients with ODVC.Patients treated for ODVC from 2011 to 2014 with a follow-up period of more than 1 year were eligible. The fundamental treatment strategy consisted of surgical treatment following intensive conservative treatment with daily teriparatide and rehabilitation for 3 months. We conducted a surgical treatment for patients who could not keep standing position by themselves because of prolonged leg paralysis or intolerable back pain. We performed a logistic regression model in which surgical treatment was set as an objective variable, and other related factors including sex, age, the level of affected vertebrae, the quality of paralysis, changing rate (δ) of spinal canal encroachment, local kyphotic angle, mobility of collapsed vertebrae, EuroQol questionnaires (EQ5D), numerical rating scale (NRS), and Frankel grade as explanatory variables. We also plotted receiver operating curves (ROCs) to investigate the cutoff values of parameters at the baseline.Thirty patients (6 males and 24 females, mean age 76.7 years) were enrolled. Eventually 12 out of 30 patients avoided surgical treatment because their symptoms were improved. Logistic regression showed that δ of local kyphotic angle (odds ratio: 1.072), P = .01), mobility of collapsed vertebrae (1.063, 0.01), EQ5D (0.98, 0.04), and NRS (1.113, 0.01) were significantly correlated with the need for surgical treatments. Among the factors at baseline, only the mobility of collapsed vertebrae showed a significant value of area under a curve (AUC = 0.727, P = .008).The results that 40% of patients with ODVC did not need further surgical treatment after the intensive conservative treatment was of great significance. Patients with greater mobility of collapsed vertebrae might be treated surgically as quickly as possible.

Trends in scientific publications of Indian spine surgeons over 14 years (2000-2013).

BACKGROUND: The number and quality of scientific publications reflects the standards of scientific research in a country. However, the contribution of Indian spine surgeons toward global publications is unknown. The goal is to study the publications of Indian spine surgeons between 2000 and 2013. MATERIALS AND METHODS: A literature search of the publications by Indian spine surgeons was performed using MEDLINE. The search terms used were India and several spine-related terminologies. The main information of the selected papers including the year of publication, scientific journal, type of pathology studied, Neurosurgical or Orthopedic Department where the study was done, type of study, and the type of article was analyzed. RESULTS: A total of 4459 articles were identified using MEDLINE and after exclusion, 507 articles were analyzed. A growth of 440% in the number of publications was observed in the period between 2009 and 2013, during which 60.15% of the articles were published. Clinical studies (n = 492; 97.04) were the most common types of articles, followed by experimental studies and other types. The Neurosurgery department published the majority of the articles (58.2%). The three most common pathologies studied were spinal tumors (17.35%), surgical technique (15.4%), and spinal infection (15.2%). CONCLUSION: The current study shows that publications in the field of spine surgery have been increasing in the last few years, although it is less. Further efforts such as research training of spine surgeons, inducing collaborations and formulation of multicenter projects and periodically allocating adequate funds are key factors to improve the scientific publications from India.

Magnetic Resonance Imaging Biomarker of Axon Loss Reflects Cervical Spondylotic Myelopathy Severity.

STUDY DESIGN: A prospective cohort study. OBJECTIVE: In this study, we employed diffusion basis spectrum imaging (DBSI) to quantitatively assess axon/myelin injury, cellular inflammation, and axonal loss of cervical spondylotic myelopathy (CSM) spinal cords. SUMMARY OF BACKGROUND DATA: A major shortcoming in the management of CSM is the lack of an effective diagnostic approach to stratify treatments and to predict outcomes. No current clinical diagnostic imaging approach is capable of accurately reflecting underlying spinal cord pathologies. METHODS: Seven patients with mild (mJOA ≥15), five patients with moderate (14≥mJOA ≥11), and two patients with severe (mJOA <11) CSM were prospectively enrolled. Given the low number of severe patients, moderate and severe patients were combined for comparison with seven age-matched controls and statistical analysis. We employed the newly developed DBSI to quantitatively measure axon and myelin injury, cellular inflammation, and axonal loss. RESULTS: Median DBSI-inflammation volume is similar in control (266 µL) and mild CSM (171 µL) subjects, with a significant overlap of the middle 50% of observations (quartile 3 - quartile 1). This was in contrast to moderate CSM subjects that had higher DBSI-inflammation volumes (382 µL; P = 0.033). DBSI-axon volume shows a strong correlation with clinical measures (r = 0.79 and 0.87, P = 1.9 x 10-5 and 2 x 10-4 for mJOA and MDI, respectively). In addition to axon and myelin injury, our findings suggest that both inflammation and axon loss contribute to neurological impairment. Most strikingly, DBSI-derived axon volume declines as severity of impairment increases. CONCLUSION: DBSI-quantified axonal loss may be an imaging biomarker to predict functional recovery following decompression in CSM. Our results demonstrate an increase of about 60% in the odds of impairment relative to the control for each decrease of 100 µL in axon volume. LEVEL OF EVIDENCE: 3.

Analysis of scientific output by spine surgeons from Japan: January 2000 to December 2013.

BACKGROUND: Over the last decade, the growing body of work on spine pathology has led to developments and refinements in the areas of basic science, diagnosis and treatment of a variety of spine conditions. Scientific publications have a global impact on the international scientific community as they share vital information that can be applied by physicians worldwide to solve their everyday medical problems. The historical background of scientific publication in journals in Japan on the subject of spine is unclear. METHODS: We performed a literature search for publications by Japanese spine surgeons regarding spine or spinal cord topics using an online database: Pubmed.gov (http://www.ncbi.nlm.nih.gov/pubmed/). The results were stored and analyzed at the Laboratory of Clinical Studies and Basic Models of Spinal Disorders of the University of Caxias do Sul. Results were limited to articles published from January 2000 to December 2013. The search terms used were "Japan" AND ("spine" OR "spinal diseases" OR "spinal cord" OR "spinal cord diseases" OR "vertebroplasty" OR "arthrodesis" OR "discectomy" OR "foraminotomy" OR "laminectomy" OR "denervation" OR "back injuries"). Japanese spine surgeons were defined as spine surgeons from orthopedic or neurosurgical specialties where the publication was affiliated with Japanese services. RESULTS: A total of 16,140 articles were identified by the Medline search. Most of the articles were excluded based on information provided in the title and abstract as they were not related to spine surgery. This study comprised 1768 articles published in the Medline database by Japanese spine surgeons from 2000 to 2013. The number of publications rose in a linear fashion, with the number of papers published increasing by 5.4 per year (p = 0.038). In recent years the publications were increasingly performed in conjunction with the neurosurgery and orthopedics specialties. CONCLUSIONS: This study showed a clear increase in publications (on Medline) by Japanese spine surgeons over the last 14 years. While this is a positive development, there is also cause for concern as there is some evidence that the number of young scientists is declining in Japan. Special attention to educating researchers and improving resources for research is crucial to further increase the number and quality of Japanese publications.

Strategy to increase research in Latin America: project on education in research by AOSpine Latin America.

BACKGROUND: The emancipatory nature of education requires research as its fundamental base, because physicians can only improve their skills and knowledge through enquiry. The number and quality of scientific publications by Latin-American spine surgeons found in the Medline database was low between 2000 and 2011. Nevertheless, the research Bank Survey of AOSpine Latin America (AOSLA) members showed that 96% of responders were very interested and motivated to perform scientific research. METHODS AND POPULATION: The research officer of AOSLA together with the Country Council and the AOSpine Research Commission established a competency-based curriculum to improve understanding of what is necessary to produce research and the best methods to achieve this goal. The research curriculum was divided into four main components: (1) research educational plan, (2) performing research, (3) technical and professional support and (4) assessment. RESULTS: The competences, learning outcomes and a syllabus on knowledge in research were developed to enable the participants to understand and perform investigations effectively. The eLearning module was designed to improve the competences to access, evaluate and use scientific information available in the main databases efficiently. Research courses were given as an isolated activity four times in Brazil and Mexico and as precourse activities six times in Brazil, Mexico and Peru. The result was an increased number of articles published and works presented at congresses. CONCLUSIONS: The project of education in research can be effectively disseminated and applied across regions, across students and across specialties.

Surgical planning and neurological outcome after anterior approach to remove a disc herniation at the C7-T1 level in 19 patients.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The purpose of this study was to report the neurological presentation, outcome and surgical planning in a series of patients with a symptomatic single-level C7-T1 disc herniation who underwent anterior surgical discectomy and fusion. SUMMARY OF BACKGROUND DATA: Disc herniations at C7-T1 are uncommon, and there are few large series in the literature describing anterior treatment of such herniations. METHODS: We performed a retrospective study of patients who underwent surgery for a C7-T1 disc herniation and reviewed the medical records, operative reports, and imaging studies. The surgeons' view line was drawn and its relation to the manubrium and the great vessels was determined on T1 sagittal magnetic resonance imaging. The location of the herniated disc in the spinal canal was determined using a T2 axial magnetic resonance imaging and classified as central, foraminal, and central/foraminal. Loss of muscle strength was evaluated preoperatively and at the last follow-up according to the classification of the Medical Research Council. The disc space was approached anteriorly by a standard cervical supramanubrial Smith-Robinson approach. RESULTS: We identified 19 patients who had undergone C7-T1 discectomy and fusion. The mean age of the sample was 54.26 ± 8.65 years. There was a higher proportion of male patients (57.9%, 11/19). The clinical presentation was predominantly motor deficit in 15/19 cases (78.9%) in intrinsic hand muscles, and usually improved after surgery. The mean follow-up period was 27.05 ± 15.10 months. All the patients underwent an anterior cervical supramanubrial approach with microdiscectomy and fusion. Anterior cervical plate fixation was used in 9/19 cases (47.3%). In the rest of the cases, a stand-alone intervertebral device was placed. CONCLUSION: An anterior cervical supramanubrial approach was easily accomplished in all patients. Motor deficit was the most common surgical indication. LEVEL OF EVIDENCE: 4.

Acute and long-term stability of atlantoaxial fixation methods: a biomechanical comparison of pars, pedicle, and intralaminar fixation in an intact and odontoid fracture model.

STUDY DESIGN: In vitro human cadaveric biomechanical study. OBJECTIVE: The aims of this project were to evaluate the acute segmental fixation and long-term screw stability afforded by 3 C2 fixation techniques: intralaminar, pars, and pedicle. SUMMARY OF BACKGROUND DATA: C2 intralaminar screws offer the advantages of avoiding the vertebral artery; however, direct biomechanical comparison of this technique to the other methods of instrumenting C2 has not been performed. METHODS: Fourteen cadaveric specimens were dual energy radiograph absorptiometry scanned and segregated into 2 groups (n = 7/group) matching the C2 bone mineral density. All specimens were instrumented with C1 lateral mass and C2 intralaminar screws while measuring the insertional torque (IT). In group 1 C2 pars screws were inserted while in group 2 pedicle screws were placed. Nondestructive testing was performed in axial rotation, flexion/extension (FE), and lateral bending. The odontoid was then resected and loading repeated. Subsequently, specimens were disarticulated about C2 and individually loaded for 2000 cycles in the cephalocaudad plane. The screws were then failed by a tensile load directed in the parasagittal plane. Full range of motion over C1-C2 and peak screw pull-out force was quantified. RESULTS.: Transpedicular technique generated significantly higher IT than the pars screws and marginally greater IT than intralaminar screws. With the intact atlantoaxial ligamentous complex, intralaminar fixation was superior to pars and similar to pedicle instrumentation at limiting axial torsion. After odontoid destabilization, however, this technique was less effective at reducing the lateral bending range of motion. Destructive loading revealed the highest pull-out forces with the pedicle screws, followed by intralaminar and pars screws. CONCLUSION: Our results suggest that C2 intralaminar fixation provides a viable alternative to pedicle screws and is superior to pars instrumentation in cases with preserved atlantoaxial ligamentous attachments. In the presence of a traumatic dens fracture, however, intralaminar fixation may not be the optimal choice.

Comparison of BRYAN cervical disc arthroplasty with anterior cervical decompression and fusion: clinical and radiographic results of a randomized, controlled, clinical trial.

STUDY DESIGN: A prospective, randomized, multicenter study of surgical treatment of cervical disc disease. OBJECTIVE: To assess the safety and efficacy of cervical disc arthroplasty using a new arthroplasty device at 24-months follow-up. SUMMARY OF BACKGROUND DATA: Cervical disc arthroplasty preserves motion in the cervical spine. It is an alternative to fusion after neurologic decompression, whereas anterior decompression and fusion provides a rigorous comparative benchmark of success. METHODS: We conducted a randomized controlled multicenter clinical trial enrolling patients with cervical disc disease. Ultimately 242 received the investigational device (Bryan Cervical Disc), and 221 patients underwent a single-level anterior cervical discectomy and decompression and fusion as a control group. Patients completed clinical and radiographic follow-up examinations at regular intervals for 2 years after surgery. RESULTS: Analysis of 12- and 24-month postoperative data showed improvement in all clinical outcome measures for both groups; however, 24 months after surgery, the investigational group patients treated with the artificial disc had a statistically greater improvement in the primary outcome variables: Neck disability index score (P = 0.025) and overall success (P = 0.010). With regard to implant- or implant/surgical-procedure-associated serious adverse events, the investigational group had a rate of 1.7% and the control group, 3.2%. There was no statistical difference between the 2 groups with regard to the rate of secondary surgical procedures performed subsequent to the index procedure. Patients who received the artificial cervical disc returned to work nearly 2 weeks earlier than the fusion patients (P = 0.015). CONCLUSION: Two-year follow-up results indicate that cervical disc arthroplasty is a viable alternative to anterior cervical discectomy and fusion in patients with persistently symptomatic, single-level cervical disc disease.

Indications and techniques for anterior cervical plating.

Anterior cervical plating is commonly performed to stabilize anterior cervical fusions. Modern plating options include dynamic plates, with screws that can either toggle within fixed holes or translate within slotted holes. Regardless of the plating system used, paramount to success and avoidance of complications with plated anterior cervical fusions are meticulous plating techniques, exacting graft carpentry, and understanding the biomechanical limitations of plating in certain situations, such as multilevel corpectomies reconstructed with a single-strut graft. In order to prevent graft-related complications associated with long-strut grafts, additional posterior fixation and fusion, or alternative corpectomy constructs, such as multilevel anterior cervical discectomy and fusion, corpectomy-discectomy, and corpectomy-corpectomy, should be considered instead if the pattern of stenosis allows.