Cervical Fusion Surgery Research Articles

Cervical Sagittal Alignment and Related Factor Analysis and Prediction Model in Patients Undergoing Revision Surgery After Anterior Cervical Fusion.

Patients with myelopathy or radiculopathy commonly undergo anterior cervical fusion surgery (ACFS), which has a notable failure rate on occasion. The goal of this study was to compare revision and nonrevision surgery patients in cervical sagittal alignment (CSA) subsequent to ACFS; additionally, to identify the best CSA parameters for predicting clinical outcome after ACFS; and furthermore, to create an equation model to assist surgeons in making decisions on patients undergoing ACFS. The data of 99 patients with symptomatic cervical myelopathy/radiculopathy who underwent ACFS were analyzed. Patients were divided into group A (underwent revision surgery after the first surgery failed) and group B (underwent only the first surgery). We measured and analyzed both preoperative and postoperative CSA parameters, including C2 slope, T1 slope, cervical lordosis C2-C7 (CL), C2-C7 sagittal vertical axis (C2C7 SVA), occiput-C2 lordosis angle (C0-C2), and chin brow vertical angle, and we further computed the correlation between the CSA parameters and created a prediction model. The (T1S-CL)-C2S mismatch differed significantly between groups A and B ([9.95 ± 9.95] 0 , [3.79 ± 6.58] 0 , P < 0.05, respectively). A significant correlation was observed between C2 slope and T1CL in group B relative to group A postoperatively (R 2 = 0.42 versus R 2 = 0.09, respectively). Compared with group B, patients in group A had significantly higher C2C7SVA values, more levels of fusion, and more smokers. The sensitivity, specificity, accuracy, and discrimination of the model were, respectively, 73.5%, 84%, 78.8%, and 85.65%. The causes of revision surgery in cervical myelopathic patients after anterior cervical corpectomy and fusion/anterior cervical diskectomy and fusion are multifactorial. (T1S-CL)-C2S mismatch and high C2C7SVA are the best cervical sagittal parameters that increase the odds of revision surgery, and the effect is more enhanced when comorbidities such as smoking, low bone-mineral density, and increased levels of fusion are taken into account.

174 Developing Mixed-Effects Models to Optimize Prediction of Postoperative Outcomes in a Modern Sample of Over 450,000 Patients Undergoing Elective Cervical Spine Fusion Surgery

INTRODUCTION: Cervical spine decompression and fusion surgery is commonly used to treat degenerative cervical spine pathologies.However, there is a paucity of high-quality data defining the optimal comorbidity indices specifically in patients undergoing cervical spine fusion surgery. METHODS: Using data from 2016–2019, we queried the Nationwide Readmissions Database (NRD) to identify individuals who had received cervical spine fusion surgery. The Johns Hopkins Adjusted Clinical Groups (JHACG) frailty-defining indicator was used to assess patient frailty. To measure the level of comorbidity, Elixhauser Comorbidity Index (ECI) scores were queried. ROC curves were developed utilizing comorbidity indices as predictor variables for pertinent complications such as death, non-routine discharge, top-quartile cost, top-quartile length of stay (LOS), and one-year readmission. RESULTS: A total of 453,717 patients were eligible for analysis. Non-routine discharges occurred in 93,961 (20.7%) patients. The mean adjusted all-payer cost for the procedure was $22,573.14 ± $18,274.86 (Top Quartile: $26,775.80) and the mean LOS was 2.7 days ± 4.4 days (Top Quartile: 4.7 days). After surgery, there were 703 (0.15%) mortalities and 58,254 (12.8%) readmissions within one year post-operatively. Models using Frailty+ECI as the primary predictor consistently outperformed the ECI only model with statistically significant p-values, as determined by comparing respective AUCs, for most of the complications assessed. Cost and mortality were the only outcomes for which this was not the case, as Frailty outperformed both ECI and Frailty+ECI in cost (p &lt; 0.0001 for all) and Frailty+ECI preformed as well as ECI alone in mortality (p = 0.10). CONCLUSIONS: Our data suggests that Frailty+ECI may most accurately predict clinical outcomes in patients receiving cervical spine surgery. These models may be used to identify high risk populations and patients who may necessitate greater resource utilization.

173 Electrical Stimulation Used as an Adjunct to Cervical Spine Fusion in Patients at Risk for Pseudarthrosis

INTRODUCTION: Prior studies show that pulsed electromagnetic field (PEMF) stimulation promotes bone healing and can be a valuable tool to help overcome biological deficiencies in patients at risk. The current study further evaluates the adjunct effect of PEMF in subjects undergoing cervical spinal surgery presenting with risk factors for pseudarthrosis. METHODS: A prospective multicenter clinical trial (NCT 03177473) was conducted at eleven clinical sites. Subjects undergoing cervical spinal fusion surgery with one or more risk factors for pseudarthrosis were identified for enrollment. Risk factors for pseudarthrosis included multilevel fusion, prior failed cervical spine fusion, diabetes, osteoporosis, or smoking. Subjects undergoing cervical spinal fusion were required to wear the PEMF device for 4 hours/day for 6 months post-op. Fusion status was determined at the 12-month visit using anterior/posterior, lateral, and flexion/extension radiographs and computed tomography (without contrast). NDI, EQ-5D, SF-36, and VAS for neck and arm pain were collected as secondary outcome measures. RESULTS: Out of 160 subjects, 144 (90.0%) were graded as fused (all levels) at the 12-month visit. Fusion success was 91.7% (n = 55/60), 89.0% (n = 89/100), and 90.9% (n = 20/22) for subjects with 1, 2+, or 3+ risk factors, respectively. Significant improvements in NDI, SF-36, EQ-5D, VAS-arm and VAS-neck were observed compared to baseline (p &lt; 0.001). A device compliance rate of 85.0% was observed at 3-months and 78.3% at 6-months in subjects who had successful cervical fusion. CONCLUSIONS: The PEMF bone growth stimulator device is a valuable tool to aid in fusion healing, especially in challenging populations. Subjects in this study experienced favorable fusion rates of 90% and significant improvement in patient reported outcomes despite having elevated comorbidity and/or complex surgeries.

A systematic review of risk factors and adverse outcomes associated with anterior cervical discectomy and fusion surgery over the past decade.

Anterior cervical discectomy and fusion (ACDF) is one of the most frequently performed cervical surgeries in the world, yet there have been several reported complications. To determine the actual incidence of complications related to ACDF as well as any risk variables that may have been identified in earlier research. To evaluate the origin, presentation, natural history, and management of the risks and the complications, we conducted a thorough assessment of the pertinent literature. An evaluation of clinical trials and case studies of patients who experienced one or more complications following ACDF surgery was done using a PubMed, Cochrane Library, and Google Scholar search. Studies involving adult human subjects that were written in the English language and published between 2012 and 2022 were included in the search. The search yielded 79 studies meeting our criteria. The overall rates of complications were as follows: Dysphagia 7.9%, psudarthrosis 5.8%, adjacent segment disease (ASD) 8.8%, esophageal perforations (EPs) 0.5%, graft or hardware failure 2.2%, infection 0.3%, recurrent laryngeal nerve palsy 1.7%, cerebrospinal fluid leak 0.8%, Horner syndrome 0.5%, hematoma 0.8%, and C5 palsy 1.9%. Results showed that dysphagia was a common postoperative sequelae with bone morphogenetic protein use and a higher number of surgical levels being the major risk factors. Pseudarthrosis rates varied depending on the factors such as asymptomatic radiographic graft sinking, neck pain, or radiculopathy necessitating revision surgery. The incidence of ASD indicated no data to support anterior cervical plating as more effective than standalone ACDF. EP was rare but frequently fatal, with no correlation found between patient age, sex, body mass index, operation time, or number of levels.

Effect of Intelligent Health Education Based on Health Belief Model on Patients With Kinesophobia After Surgical Treatment of Cervical Spondylosis

To explore the application effect of intelligent health education based on the health belief model on patients with postoperative kinesophobia after surgical treatment of cervical spondylosis. A prospective cohort study was conducted with patients who underwent anterior cervical discectomy, decompression, and fusion surgery with a single central nerve and spine center, and who had postoperative kinesophobia, ie, fear of movement. The patients made voluntary decisions concerning whether they would receive the intervention of intelligent health education. The patients were divided into a control group and an intelligent education group and the intervention started on the second day after the surgery. The intelligent education group received intelligent education starting from the second day after surgery through a WeChat widget that used the health belief model as the theoretical framework. The intelligent health education program was designed according to the concept of patient problems, needs, guidance, practice, and feedbacks. It incorporated four modules, including knowledge, intelligent exercise, overcoming obstacles, and sharing and interaction. It had such functions as reminders, fun exercise, shadowing exercise, monitoring, and documentation. Health education for the control group also started on the second day after surgery and was conducted by a method of brochures of pictures and text and WeChat group reminder messages. The participants were surveyed before discharge and 3 months after their surgery. The primary outcome measure compared between the two groups was the degree of kinesophobia. Secondary outcome measures included differences in adherence to functional exercise (Functional Exercise Adherence Scale), pain level (Visual Analogue Scale score), degree of cervical functional impairment (Cervical Disability Index), and quality of life (primarily assessed by the Quality of Life Short Form 12 [SF-12] scale for psychological and physiological health scores). A total of 112 patients were enrolled and 108 patients completed follow-up. Eventually, there were 53 cases in the intelligent education group and 55 cases in the control group. None of the patients experienced any sports-related injuries. There was no statistically significant difference in the primary and secondary outcome measures between the two groups at the time of discharge. At the 3-month follow-up after the surgery, the level of kinesophobia in the intelligent education group (25.72±3.90) was lower than that in the control group (29.67±6.16), and the difference between the two groups was statistically significant (P<0.05). In the intelligent education group, the degree of pain (expressed in the median [25th percentile, 75th percentile]) was lower than that of the control group (0 [0, 0] vs. 1 [1, 2], P<0.05), the functional exercise adherence was better than that of the control group (63.87±7.26 vs. 57.73±8.07, P<0.05), the psychological health was better than that of the control group (40.78±3.98 vs. 47.78±1.84, P<0.05), and the physical health was better than that of the control group (43.16±4.41 vs. 46.30±3.80, P<0.05), with all the differences being statistically significant. There was no statistically significant difference in the degree of cervical functional impairment between the two groups (1 [1, 2] vs. 3 [2, 7], P>0.05). Intelligent health education based on the health belief model can help reduce the degree of kinesophobia in patients with postoperative kinesophobia after surgical treatment of cervical spondylosis and improve patient prognosis.

The influence of anterior cervical discectomy and fusion surgery on cervical muscles and the correlation between related muscle changes and surgical efficacy

BackgroundAnterior cervical discectomy and fusion surgery (ACDF) is a common technique in treating degenerative cervical spondylosis. This study is to evaluate the changes of cervical muscles after ACDF and analyze the correlation between related muscle changes and clinical efficacy.MethodsSixty-five postoperative patients (single-level ACDF) with cervical spondylotic myelopathy from January 2013 to December 2022 were analyzed. The measured parameters include: the axial section of longus colli cross-sectional area (AxCSA), the volume of cervical longus, the ratio of long and short diameter line (RLS), the cervical extensor cross-sectional area (CESA), the vertebral body area (VBA), and the CESA/VBA. The visual analog scale (VAS), modified Japanese Orthopedic Association score (mJOA), and neck disability index (NDI) were evaluated. The changes in muscle morphology were analyzed, and the correlation analysis was conducted between morphological changes and function scores.ResultsThe postoperative AxCSA of surgical segment (3rd month, 12th month, and the last follow-up) was decreased compared to preoperative (141.62 ± 19.78), and the differences were significant (P < 0.05). The corresponding data reduced to (119.42 ± 20.08) mm2, (117.59 ± 19.69) mm2, and (117.41 ± 19.19) mm2, respectively (P < 0.05). The RLS increased, and the volume of cervical longus decreased significantly after surgery (P < 0.05). Negative correlation was found between postoperative volume of cervical longus and VAS at the 3rd month (r = − 0.412), 12th month (r = − 0.272), and last follow-up (r = − 0.391) (P < 0.05). Negative correlation existed between postoperative volume of cervical longus and NDI at the 3rd month (r = − 0.552), 12th month (r = − 0.293), and last follow-up (r = − 0.459) (P < 0.05).ConclusionThe volume of cervical longus decreased and its morphology changed after ACDF surgery. The mainly affected muscle was the cervical longus closing to the surgical segment. Negative correlation was found between the postoperative volume of cervical longus and function scores (VAS and NDI).

Clinical Outcomes of Anterior Cervical Decompression and Fusion Therapy for Patients With Hirayama Disease

To investigate the clinical outcomes of anterior cervical decompression and fusion (ACDF) surgery for the treatment of Hirayama disease (HD). In this study, 15 patients with HD who underwent ACDF operation between March 2022 and March 2023 with complete data were retrospectively analyzed. Following the diagnosis, conservative treatment was ineffective, and thus, disease progression severely affected the quality of life of patients. ACDF was performed in the China-Japan Friendship Hospital, and patients were regularly followed up postoperatively. The cervical range of motion (ROM), the anteroposterior and transverse diameter of the spinal cord, and their ratio were measured before and after the operation. The neurological function of patients before and after the last follow-up was evaluated using the selected brief-Michigan Hand Questionnaire (sb-MHQ), whilst the overall therapeutic effect after the operation was evaluated using Odom's criteria. All patients were followed up for an average of 12 ±4.5 (6-18) months. Dynamic X-ray displayed that the ROM of cervical vertebrae decreased from 72.73 ±12.72 ° (53-97 °) to 33.53 °±10.34 ° (15-54 °) (P < 0.001). Moreover, flexion cervical MRI performed after the operation revealed that spinal cord compression was markedly relieved, and the ratio of the anteroposterior diameter of the spinal cord to the transverse diameter increased from 0.27 ±0.09 to 0.43 ±0.03 (P < 0.001). At the last follow-up visit, finger extension tremor symptoms were alleviated, although they did not completely disappear. Contrastingly, muscle atrophy showed no significant improvement. Finally, the sb-MHQ score significantly increased from 17.33 ±1.76 preoperatively to 24.80 ±1.78 at the last follow-up (P < 0.001). Our results collectively highlighted the efficacy of ACDF for the treatment of HD. This procedure can limit excessive cervical flexion and repeated compression of the spinal cord during cervical movement and considerably improve upper limb functions.

Comparison of head positioning using the Mayfield skull clamp versus padded headrest in anterior cervical discectomy and fusion surgery.

Anterior cervical discectomy and fusion (ACDF) is a commonly implemented surgical intervention for a variety of pathologies affecting the cervical spine. The current literature and daily practice reveal variations on patient head positioning for this procedure with both rigid fixations in the Mayfield skull clamp as well as use of a padded headrest being used. In this study, we therefore examine whether patients undergoing surgery using head positioning in the Mayfield skull clamp versus a padded headrest differ in regard to adverse events, surgical parameters and clinical outcome. A single-center, retrospective analysis of 121 patients treated with ACDF for degenerative disease, traumatic cervical spine injury and infectious disease between November 2019 and March 2023 was performed. Clinical and imaging data for 59 patients positioned in the Mayfield skull clamp and 62 patients positioned in a padded headrest were evaluated using electronic medical records. In addition to demographic data, surgical indications, procedures performed were analyzed for both groups. Level of training (chief, attending and resident), length of surgery and intraoperative radiation exposure (measured by dose area product and total radiation time) were also examined. Finally, modified Rankin Scale (mRS) preoperatively and at last follow-up as well as adverse events were compared between groups. We found no statistically significant differences between the Mayfield and headrest groups regarding surgical indications (P=0.583), procedures performed (P=0.069), level of training of the surgeon (P=0.218), length of surgery (P=0.752), adverse events (P=0.619) or neurological impairment (P=0.080) following surgical intervention. There was a significant difference regarding dose area product between both groups with patients positioned in the Mayfield skull clamp showing lower mean levels of radiation than those in the headrest group (99 versus 131 cGy/cm2; P=0.003). Patient positioning using the Mayfield skull clamp may reduce required radiation exposure during ACDF procedures versus use of a padded headrest.

Anatomical Brushite-Coated Mg-Nd-Zn-Zr Alloy Cage Promotes Cervical Fusion: One-Year Results in Goats.

In this study, an anatomical brushite-coated Mg-Nd-Zn-Zr alloy cage was fabricated for cervical fusion in goats. The purpose of this study was to investigate the cervical fusion effect and degradation characteristics of this cage in goats. The Mg-Nd-Zn-Zr alloy cage was fabricated based on anatomical studies, and brushite coating was prepared. Forty-five goats were divided into three groups, 15 in each group, and subjected to C2/3 anterior cervical decompression and fusion with tricortical bone graft, Mg-Nd-Zn-Zr alloy cage, or brushite-coated Mg-Nd-Zn-Zr alloy cage, respectively. Cervical radiographs and computed tomography (CT) were performed 3, 6, and 12 months postoperatively. Blood was collected for biocompatibility analysis and Mg2+ concentration tests. The cervical spine specimens were obtained at 3, 6, and 12 months postoperatively for biomechanical, micro-CT, scanning electron microscopy coupled with energy dispersive spectroscopy, laser ablation-inductively coupled plasma-time-of-flight mass spectrometry, and histological analysis. The liver and kidney tissues were obtained for hematoxylin and eosin staining 12 months after surgery for biosafety analysis. Imaging and histological analysis showed a gradual improvement in interbody fusion over time; the fusion effect of the brushite-coated Mg-Nd-Zn-Zr alloy cage was comparable to that of the tricortical bone graft, and both were superior to that of the Mg-Nd-Zn-Zr alloy cage. Biomechanical testing showed that the brushite-coated Mg-Nd-Zn-Zr alloy cage achieved better stability than the tricortical bone graft at 12 months postoperatively. Micro-CT showed that the brushite coating significantly decreases the corrosion rate of the Mg-Nd-Zn-Zr alloy cage. In vivo degradation analysis showed higher Ca and P deposition in the degradation products of the brushite-coated Mg-Nd-Zn-Zr alloy cage, and no hyperconcentration of Mg was detected. Biocompatibility analysis showed that both cages were safe for cervical fusion surgery in goats. To conclude, the anatomical brushite-coated Mg-Nd-Zn-Zr alloy cage can promote cervical fusion in goats, and the brushite-coated Mg-Nd-Zn-Zr alloy is a potential material for developing absorbable fusion cages.

Reliable Prediction of Discharge Disposition Following Cervical Spine Surgery With Ensemble Machine Learning and Validation on a National Cohort.

A retrospective cohort study. The purpose of this study is to develop a machine learning algorithm to predict nonhome discharge after cervical spine surgery that is validated and usable on a national scale to ensure generalizability and elucidate candidate drivers for prediction. Excessive length of hospital stay can be attributed to delays in postoperative referrals to intermediate care rehabilitation centers or skilled nursing facilities. Accurate preoperative prediction of patients who may require access to these resources can facilitate a more efficient referral and discharge process, thereby reducing hospital and patient costs in addition to minimizing the risk of hospital-acquired complications. Electronic medical records were retrospectively reviewed from a single-center data warehouse (SCDW) to identify patients undergoing cervical spine surgeries between 2008 and 2019 for machine learning algorithm development and internal validation. The National Inpatient Sample (NIS) database was queried to identify cervical spine fusion surgeries between 2009 and 2017 for external validation of algorithm performance. Gradient-boosted trees were constructed to predict nonhome discharge across patient cohorts. The area under the receiver operating characteristic curve (AUROC) was used to measure model performance. SHAP values were used to identify nonlinear risk factors for nonhome discharge and to interpret algorithm predictions. A total of 3523 cases of cervical spine fusion surgeries were included from the SCDW data set, and 311,582 cases were isolated from NIS. The model demonstrated robust prediction of nonhome discharge across all cohorts, achieving an area under the receiver operating characteristic curve of 0.87 (SD=0.01) on both the SCDW and nationwide NIS test sets. Anterior approach only, age, elective admission status, Medicare insurance status, and total Elixhauser Comorbidity Index score were the most important predictors of discharge destination. Machine learning algorithms reliably predict nonhome discharge across single-center and national cohorts and identify preoperative features of importance following cervical spine fusion surgery.

What Is the Evidence Supporting Osteobiologic Use in Revision Anterior Cervical Discectomy and Fusion?

Systematic literature review. To analyze the literature and describe the evidence supporting osteobiologic use in revision anterior cervical discectomy and fusion (ACDF) surgery. A systematic search of PubMed/MEDLINE, EMBASE, Cochrane library, and ClinicalTrials.gov databases was conducted for literature reporting the use of osteobiologics in revision ACDF. We searched for studies reporting outcomes of using any osteobiologic use in revision ACDF surgeries (independently of the number of levels) in the above databases. There are currently no studies in the literature describing the outcome and comparative efficacy of diverse osteobiologic agents in the context of revision ACDF surgery. A majority of the current evidence is based only upon studies involving primary ACDF surgery. The current study highlights the paucity of literature evidence on the role of diverse osteobiologics in revision ACDF, and foregrounds the need for high-quality evidence on this subject.

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.

Systematic review and meta-analysis. 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. 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. 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. 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.

Do Osteobiologics Augment Fusion in Anterior Cervical Discectomy and Fusion Surgery Performed With Mechanical Interbody Devices (Polyether ether ketone, Carbon Fiber, Metal Cages) and is the Fusion Rate Comparable to that With Autograft? A Systematic Review.

Systematic Review of the Literature. The purpose of this study was to perform a systematic review describing fusion rates for anterior cervical discectomy and fusion (ACDF) using autograft vs various interbody devices augmented with different osteobiologic materials. A systematic review limited to the English language was performed in Medline, Embase and Cochrane library using Medical Subject Heading (MeSH) terms. Studies that evaluated fusion after ACDF using autografts and osteobiologics combined with PEEK, carbon fibre, or metal cages were searched for. Articles in full text that met the criteria were included in the review. The main outcomes evaluated were the time taken to merge, the definition of the fusion assessment, and the modality of the fusion assessment. The risk of bias of each article was assessed by the MINORS score or ROB 2.0 depending on the randomisation process. The total number of references reviewed was six hundred and eighty-two. After applying the inclusion criteria, 54 were selected for the retrieval of the full text. Eight studies were selected and included for final analysis in this study. Fusion rates were reported between 83.3% and 100% for autograft groups compared to 46.5% and 100% for various interbody device/osteobiological combinations. The overall quality of the evidence in all radiographic fusion studies was considered insufficient due to a serious risk of bias. Mechanical interbody devices augmented with osteobiologics performed similarly to autografts in terms of reliability and efficacy. Their time to fusion and fusion rate were comparable to autografts at the end of the final follow-up.

Complications With Demineralized Bone Matrix, Hydroxyapatite and Beta-Tricalcium Phosphate in Single and Two-Level Anterior Cervical Discectomy and Fusion Surgery.

Systematic literature review. To analyze the evidence available reporting complications in single or two-level anterior cervical discectomy and fusion (ACDF) using a demineralized bone matrix (DBM), hydroxyapatite (HA), or beta-tricalcium phosphate (β-TCP). A systematic review of the literature using PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov databases was performed in August 2020 to identify studies reporting complications in one or two-level ACDF surgery using DBM, HA, or β-TCP. The study was reported following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. A total of 1857 patients were included, 981 male and 876 female, across 17 articles; 5 prospective, and 12 retrospectives. We noted heterogeneity among the included studies concerning the study design and combination of graft materials utilized in them. However, we noted a higher incidence of adjacent segment disease (17.7%) and pseudoarthrosis (9.3%) in fusion constructs using DBM. Studies using β-TCP reported a higher incidence of pseudoarthrosis (28.2%) and implant failures (17.9%). Degenerative cervical conditions treated with one or two-level ACDF surgery using DBM, HA, or β-TCP with or without cervical plating are associated with complications such as adjacent segment disease, dysphagia, and pseudarthrosis. However, consequent to the study designs and clinical heterogeneity of the studies, it is not possible to correlate these complications accurately with any specific graft material employed. Further well-designed prospective studies are needed to correctly know the related morbidity of each graft used for achieving fusion in ACDF.

Biomechanical study of anterior transpedicular root screw intervertebral fusion system of lower cervical spine: a finite element analysis.

Background: The cervical anterior transpedicular screw (ATPS) fixation technology can provide adequate stability for cervical three-column injuries. However, its high risk of screw insertion and technical complexity have restricted its widespread clinical application. As an improvement over the ATPS technology, the cervical anterior transpedicular root screw (ATPRS) technology has been introduced to reduce the risk associated with screw insertion. This study aims to use finite element analysis (FEA) to investigate the biomechanical characteristics of a cervical spine model after using the novel ATPRS intervertebral fusion system, providing insights into its application and potential refinement. Methods: A finite element (FE) model of the C3-C7 lower cervical spine was established and validated. After two-level (C4-C6) anterior cervical discectomy and fusion (ACDF) surgery, FE models were constructed for the anterior cervical locked-plate (ACLP) internal fixation, the ATPS internal fixation, and the novel ATPRS intervertebral fusion system. These models were subjected to 75N axial force and 1.0 Nm to induce various movements. The range of motion (ROM) of the surgical segments (C4-C6), maximum stress on the internal fixation systems, and maximum stress on the adjacent intervertebral discs were tested and recorded. Results: All three internal fixation methods effectively reduced the ROM of the surgical segments. The ATPRS model demonstrated the smallest ROM during flexion, extension, and rotation, but a slightly larger ROM during lateral bending. Additionally, the maximum bone-screw interface stresses for the ATPRS model during flexion, extension, lateral bending, and axial rotation were 32.69, 64.24, 44.07, 35.89MPa, which were lower than those of the ACLP and ATPS models. Similarly, the maximum stresses on the adjacent intervertebral discs in the ATPRS model during flexion, extension, lateral bending, and axial rotation consistently remained lower than those in the ACLP and ATPS models. However, the maximum stresses on the cage and the upper endplate of the ATPRS model were generally higher. Conclusion: Although the novel ATPRS intervertebral fusion system generally had greater endplate stress than ACLP and ATPS, it can better stabilize cervical three-column injuries and might reduce the occurrence of adjacent segment degeneration (ASD). Furthermore, further studies and improvements are necessary for the ATPRS intervertebral fusion system.

The Efficacy of Cervical Pedicle Screw Is Enhanced When Used With 5.5-mm Rods for Metastatic Cervical Spinal Tumor Surgery.

The cervical spine presents challenges in treating metastatic cervical spinal tumors (MCSTs). Although the efficacy of cervical pedicle screw placement (CPS) has been well established, its use in combination with 5.5-mm rods for MCST has not been reported. This study aimed to evaluate the efficacy of CPS combined with 5.5-mm rods in treating MCST and compare it with that of CPS combined with traditional 3.5-mm rods. This retrospective study analyzed 58 patients with MCST who underwent posterior cervical spinal fusion surgery by a single surgeon between March 2012 and December 2022. Data included demographics, surgical details, imaging results, numerical rating scale score for neck pain, Eastern Cooperative Oncology Group performance status, and Spine Oncology Study Group Outcomes Questionnaire responses. Preoperative Spinal Instability Neoplastic Scores were significantly higher in the 5.5-mm rod group. Greater kyphotic changes in the index vertebra were observed in the 3.5-mm rod group. Neck pain reduction was significantly better in the 5.5-mm rod group. CPS with 5.5-mm rods provides superior biomechanical stability and effectively resists forward bending momentum in posterior MCST fusion surgery. These findings support the use of 5.5-mm rods to enhance surgical outcomes.

Three Episodes of Postanesthesia Paradoxical Vocal Cord Motion Disorder in the Same Patient: A Case Report.

Postanesthesia paradoxical vocal cord motion disorder (PVCMD) is often benign. However, if not recognized, PVCMD can lead to unnecessary treatments. Our patient had 3 different surgeries over a period of 20 months. The first episode of PVCMD occurred after a shoulder surgery, and the patient was reintubated. PVCMD was correctly diagnosed and treated successfully with reassurance after an ulnar nerve decompression. The third episode of PVCMD occurred after a cervical fusion surgery. Prevertebral edema from surgery further compromised the airways. Our case demonstrates the challenges of identifying and managing perioperative PVCMD, especially when surgical complications confound the airway management.

Intraoperative Protection of Pharyngeal Autonomic Nerves: Preventing Dysphagia After Anterior Cervical Decompression and Fusion Surgery

The study aims to investigate whether intraoperative protection of the pharyngeal autonomic nerve can effectively reduce the incidence of postoperative dysphagia following anterior cervical decompression and fusion surgery (ACDF). A retrospective analysis was conducted on 130 cases that underwent ACDF from January 2018 to June 2022 at our hospital. Divided into nonautonomic neuroprotection (NANP) group and autonomic neuroprotection group based on whether receive protective measures for the pharyngeal autonomic nerve during surgery. General data were recorded and compared between the 2 groups. Postoperative outcomes were evaluated using Neck Disability Index, Japanese Orthopaedics Association (JOA) score, and JOA improvement rate. The incidence and severity of postoperative dysphagia were assessed using Bazaz dysphagia assessment criteria and swallowing-quality of life questionnaire. There were no significant differences in general data (P > 0.05). The average operation time and intraoperative blood loss also showed no significant differences (P > 0.05). Both groups showed significant improvements in Neck Disability Index and JOA scores at all follow-up time points compared to preoperative scores (P < 0.01). The incidence of postoperative dysphagia in the autonomic neuroprotection group was significantly lower than that in the NANP group at all follow-up time points (P< 0.05). Both group showed a significant reduction in scores 3 days postoperatively compared to preoperative scores (P < 0.01), and the NANP group also showed significant reductions in scores at 3 month and 1 year postoperative follow-up time points compared to preoperative scores (P < 0.01). The adoption of pharyngeal autonomic nerve protective measures during ACDF can effectively lower the probability of postoperative dysphagia.

Design, fabrication, and evaluation of single- and multi-level 3D-printed non-covering cervical spinal fusion surgery templates.

Cervical spinal fusion surgeries require accurate placement of the pedicle screws. Any misplacement/misalignment of these screws may lead to injuries to the spinal cord, arteries and other organs. Template guides have emerged as accurate and cost-effective tools for the safe and rapid insertions of pedicle screws. Novel patient-specific single- and multi-level non-covering templates for cervical pedicle screw insertions were designed, 3D-printed, and evaluated. CT scans of two patients were acquired to reconstruct their 3D spine model. Two sets of single-level (C3-C7) and multi-level (C4-C6) templates were designed and 3D-printed. Pedicle screws were inserted into the 3D-printed vertebrae by free-hand and guided techniques. For single-level templates, a total of 40 screws (2 patients × 5 vertebrae × 2 methods × 2 screws) and for multi-level templates 24 screws (2 patients × 3 vertebrae × 2 methods × 2 screws) were inserted by an experienced surgeon. Postoperative CT images were acquired to measure the errors of the entry point, 3D angle, as well as axial and sagittal plane angles of the inserted screws as compared to the initial pre-surgery designs. Accuracy of free-hand and guided screw insertions, as well as those of the single- and multi-level guides, were also compared using paired t-tests. Despite the minimal removal of soft tissues, the 3D-printed templates had acceptable stability on the vertebrae during drillings and their utilization led to statistically significant reductions in all error variables. The mean error of entry point decreased from 3.02mm (free-hand) to 0.29mm (guided) using the single-level templates and from 5.7mm to 0.76mm using the multi-level templates. The percentage reduction in mean of other error variables for, respectively, single- and multi-level templates were as follows: axial plane angle: 72% and 87%, sagittal plane angle: 56% and 78%, and 3D angle: 67% and 83%. The error variables for the multi-level templates generally exceeded those of the single-level templates. The use of single- and multi-level templates also considerably reduced the duration of pedicle screw placements. The novel single- and multi-level non-covering templates are valuable tools for the accurate placement of cervical pedicle screws.

An Overview of Recent Advances in Anterior Cervical Decompression and Fusion Surgery.

Anterior cervical diskectomy and fusion (ACDF) has evolved significantly in the last few years with the aim of enhancing effectiveness and safety while reducing hospitalization and healthcare-related costs. Transitioning from iliac crest autografts to allografts minimizes donor-site complications like pain, infections, and hematoma. Allograft options, such as polyetheretherketone (PEEK) and tantalum, vary in their osteoinductive properties and elastic modulus, influencing fusion rates, time, and the rate of subsidence. Recently introduced zero-profile cages offer bone fixation through screws, resulting in reduced blood loss, improved spinal alignment, and decreased complications like dysphagia and adjacent segment disease. Intraoperative neuromonitoring (IONM) has gained widespread use. The North American Spine Society (NASS) 2023 recommendations endorse IONM in cervical deformity corrections and myelopathy cases. Insufficient studies hinder clear radiculopathy recommendations, but emerging research supports IONM for patients at greater risk of C5 nerve root injury or positional injury. Advancements in hemostatic agents, such as gelatin sponges, oxidized cellulose, and fibrin sealants, contribute to safety by reducing postoperative hematoma rates and eliminating the need for drainage. Innovations like the exoscope, endoscope, and computed-tomography (CT) navigation have transformed surgical practices. Exoscopes are emerging as an alternative to microscopes, offering benefits like a smaller footprint, adjustable positioning, lower costs, and shared intraoperative views for educational purposes. The use of endoscope offers the possibility of performing a minimally invasive technique with improved results in terms of cosmesis and patient-perceived outcome. CT navigation can be useful in high-risk procedures, such as cervical plate placement for major instability. This paper provides an overview of cutting-edge technologies in ACDF surgery, emphasizing cage materials and designs, safety measures, and operating room advancements. It also highlights areas for future research, underlining the procedure's continuous evolution.