Anterior Cervical Discectomy And Fusion Research Articles

Positive Cutibacterium acnes Intervertebral Discs Are Not Associated with Subsidence Following Anterior Cervical Discectomy and Fusion at 3 or 6 Months.

Background/Objectives:Cutibacterium acnes (C. acnes), formerly known as Propionibacterium acnes (P. acnes), is an anaerobic, low-virulent bacterium that has been associated with postoperative infections of the shoulder, knee, and cervical spine. Recent studies have highlighted an association between C. acnes and the development of degenerative disc disease (DDD). The aim of this study is to ascertain whether C. acnes increases the risk of subsidence following anterior cervical discectomy and fusion (ACDF). Methods: After IRB approval, consecutive patients undergoing elective ACDF for DDD from 2017 to 2018 were enrolled in this prospective cohort study. Intervertebral disc samples were taken at each affected level and cultured. A total of 66 patients with radiographic follow-ups were included in the final analysis. The extent of subsidence and cervical lordosis was determined immediately postoperatively and at the 3- and 6-month follow-ups. Results: No significant difference in subsidence was observed at 3 months (p = 0.07) or 6 months (p = 0.11) between culture-positive and -negative cohorts. Additionally, there was no significant difference detected in the change in cervical lordosis observed at 3 months (p = 0.16) or 6 months (p = 0.27) between culture-positive and -negative cohorts. For the most inferiorly fused segment, there was a significant difference in subsidence observed at 3 months (1.5 mm, 95% CI: 0.2-2.7 mm, p = 0.02) but not at 6 months (p = 0.17). Conclusions: Intervertebral discs with a positive C. acnes culture were not associated with greater levels of subsidence at 3 or 6 months following ACDF for DDD. Further research is necessary to endorse these results and to gauge the clinical significance of C. acnes infection.

Impact of congenital spinal stenosis on the outcome of three-level anterior cervical discectomy and fusion in patients with cervical spondylotic myelopathy: a retrospective study.

To investigate whether congenital cervical spinal stenosis (CCSS) affects the outcome of three-level anterior cervical discectomy and fusion (ACDF) in patients with cervical spondylotic myelopathy (CSM). One hundred seventeen patients with CSM who underwent three-level ACDF between January 2019 and January 2023 were retrospectively examined. Patients were grouped according to presence of CCSS, which was defined as Pavlov ratio ≤ 0.75. The CCSS and no CCSS groups comprised 68 (58.1%) and 49 (41.9%) patients, respectively. The Japanese Orthopaedic Association (JOA) score did not significantly differ between the two groups at any postoperative time point (p > 0.05). The JOA improvement rate was lower in the CCSS group 1 month after surgery (41.7% vs. 45.5%, p < 0.05), but showed no difference at any follow-up time point after one month. Multivariate logistic regression identified preoperative age (OR = 10.639), JOA score (OR = 0.370), increased signal intensity (ISI) in the spinal cord on T2-weighted MRI (T2-WI) (Grade 1: OR = 6.135; Grade 2: OR = 29.892), and degree of spinal cord compression (30-60%: OR = 17.919; ≥60%: OR = 46.624) as independent predictors of a poor oneyear outcome (JOA recovery rate < 50%). Although early JOA improvement is slower in the CCSS group, it does not affect the final neurological improvement at 1 year. Therefore, CCSS should not be considered a contraindication for three-level ACDF in patients with CSM. The main factors influencing oneyear outcome were preoperative age, JOA score, ISI grade, and degree of spinal cord compression.

The Effect of a Cervical Brace on Postoperative Axial Symptoms Following Single-level Anterior Cervical Discectomy and Fusion.

Retrospective study. This study aims to investigate the effect of cervical brace utilization on postoperative axial symptoms in patients undergoing single-segment anterior cervical discectomy and fusion (ACDF). Anterior cervical discectomy and fusion (ACDF) is the most commonly used surgical method in the treatment of cervical spondylosis. For patients with single-segment ACDF. The absence of a neck brace after surgery is safe and does not affect the outcome of surgery. However, the effect on the incidence of AS is unclear. Patients who underwent anterior cervical single-segment ACDF between May 2020 and August 2021 were retrospectively analyzed. Participants were divided into brace group and nonbraced groups. The incidence of axial symptoms, cervical mobility, and postoperative quality of life were then compared between the 2 groups. A total of 121 patients were included in this study: 62 in the brace group and 59 in the nonbraced group. There were no statistically significant variations observed in the overall demographic characteristics, including age, sex, body mass index, smoking status, and disease duration. The study findings showed that there was a significant decrease in the occurrence of axial symptoms among patients in nonbraced group, in addition to a considerable increase in cervical mobility 1 month following the surgery. The omission of a cervical brace following surgery in patients undergoing single-segment ACDF reduced the incidence of early postoperative axial symptoms, improved their overall quality of life, and facilitated the recovery of postoperative cervical mobility.

Structural Allograft versus Polyetheretherketone Cage in Anterior Cervical Discectomy and Fusion: A Meta-Analysis

Polyetheretherketone (PEEK) cages and structural allografts (SAs) are commonly used in Anterior Cervical Discectomy and Fusion (ACDF), yet their postoperative results remain uncertain. This meta-analysis was conducted to determine whether there were any differences in outcomes between patients who received these two grafts in ACDF. We comprehensively searched electronic databases up to August 2023. Observational studies or randomized controlled trials reported postoperative outcomes, including fusion, subsidence, reoperation rates, and patient-reported outcomes through the Neck Disability Index (NDI), the Visual Analog Scale (VAS) for neck and arm pain, and the Japanese Orthopedic Association (JOA)/modified JOA score following primary ACDF using SA or PEEK cage. The results are presented in odds ratios (ORs) or mean differences with corresponding 95% confidence intervals (CIs). Eleven studies were included, with 1213 patients (788 receiving SAs and 425 receiving PEEK cages). Patients having SA had significantly higher fusion (OR: 1.84, 95% CI: 1.27-2.67, p = 0.001) and lower subsidence (OR: 0.50, 95%CI: 0.30-0.86, p = 0.01) rates when compared with the PEEK cage. There was no difference in revision rate between SA or PEEK cage (p = 0.88). Two grafts demonstrated similar clinical improvements in NDI (p = 0.31), VAS for the neck (p = 0.77) and arm pain (p = 0.22), and JOA/mJOA score (p = 0.99). SA demonstrates better fusion and lower subsidence rates than the PEEK cage in ACDF. Nevertheless, these two cages resulted in equally successful postoperative clinical performances.

Anterior Cervical Discectomy and Fusion for the Treatment of Pincer Cervical Spondylotic Myelopathy: A Single-Center Retrospective Study

BackgroundAnterior and posterior compression of the cervical spinal cord is usually called pincer cervical spondylotic myelopathy (p-CSM), and surgery is generally recommended; however, there is some controversy about the choice of surgical approach because single anterior or posterior surgery cannot effectively relieve contralateral compression, and combined surgery may cause problems related to trauma and effects on cervical spine function. ObjectiveTo investigate the feasibility and indications of single anterior cervical discectomy and fusion (ACDF) for the treatment of p-CSM. MethodsThe data of twenty-one p-CSM patients who were treated with ACDF at a single center from 2019 to 2022 were collected. Neurological status was evaluated by the Japanese Orthopedic Association (JOA) scoring system. The radiological parameters included the percentage of space occupied by the spinal canal, the cervical sagittal Cobb angle, and the cross-sectional area of the spinal cord before and after the operation. Complications and spinal cord compression rates were also observed. Correlations between the decompressive effects and various prognostic factors were statistically analyzed. ResultsThe mean follow-up period was 24.1±3.55 months. The average JOA score significantly increased, with a mean recovery rate of 65.88±8.97%. The fusion rate was satisfactory. Correlation analysis revealed that the number of operation segments and age were important predictors of decompressive effects. There was no further deterioration of spinal cord function after the operation. ConclusionACDF is an effective method for treating pincer spinal cord compression in terms of neurological recovery, radiological parameters, fusion rates, and complications, especially for patients younger than 60 years of age with single operative segments.

Cervical Collar Use Following Cervical Spine Surgery: A Systematic Review.

The utility and risks associated with the use of cervical collars in the postoperative period after cervical spine surgery have been of debate. The purpose of this study was to systematically review the currently available evidence on the use of cervical collars after cervical spine surgery to assess their impact on outcomes. A literature search of the PubMed database was performed using keywords "cervical collar," "anterior cervical discectomy and fusion (ACDF)," "posterior cervical decompression and fusion," "laminoplasty," "post-operative orthotic bracing," "cervical decompression," and "cervical orthosis" in all possible combinations. All English studies with the level of evidence of I to IV that were published from May 1, 1986, to December 3, 2023, were considered for inclusion. A total of 25 articles meeting the inclusion criteria were identified and reviewed. Regarding anterior and posterior fusion procedures, cervical collar use demonstrated improved short-term patient-reported outcomes and pain control. While surgeon motivation for collar use was to increase fusion rates, this is not well drawn out in the literature with the majority of studies demonstrated no significant difference in fusion rates between patients who wore a cervical collar and those who did not. Regarding motion-preserving procedures such as cervical laminoplasty, patients with prolonged postoperative cervical collar use demonstrated increased rates of axial neck pain and decreased final range of motion (ROM). Surgeon motivation for postoperative cervical collar immobilization after completion of fusion procedures is to increase fusion rates and improve postoperative pain and disability despite this not being fully drawn out in the literature. After completion of motion-sparing procedures, the benefits of collar immobilization diminish with their prolonged use which could lead to increased rates of axial neck pain and decreased ROM. Cervical collar immobilization in the postoperative period should be considered its own intervention, with its own associated risk-benefit profile. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Outcomes following two-level Cervical Disc Arthroplasty Relative to two-level Anterior Cervical Discectomy.

Retrospective cohort study. To evaluate postoperative adverse events, readmissions, and five-year survival to reoperation for two-level cervical disc arthroplasty (CDA) relative to two-level anterior cervical discectomy and fusion (ACDF). CDA and ACDF are both treatment options for degenerative cervical spine pathology. Relative to ACDF, CDA is a relatively novel treatment option, and limited research exists comparing outcomes between two-level CDA and two-level ACDF. Patients undergoing two-level CDA or two-level ACDF were isolated from the PearlDiver M165Ortho database. These two cohorts were matched 1:1 based on patient age, sex, and Elixhauser Comorbidity Index (ECI) scores. The odds of 90-day postoperative adverse events were compared between the two groups by multivariable analysis. Overall cost-of-care for the first 90-days postoperatively, and five-year survival to cervical spine reoperation were then assessed. Of the two-level cases identified, only 3.9% had CDA and the rest had ACDF. After matching, there were 4,224 patients in each of the study groups. With controlling for patient age, sex, and ECI on multivariable analysis, two-level CDA patients had significantly lower odds of experiencing 90-day dysphagia (OR 0.60, P<0.0001 driving aggregated any adverse event [OR 0.65, P<0.0001]) and readmission (OR 0.69, P=0.0002). Median 90-day cost of care was greater for two-level ACDF patients ($4,776.00 vs. $3,191.00, P<0.0001). No significant difference in five-year survival to cervical spine reoperation was identified (P=0.7). Relative to two-level ACDF patients, two-level CDA patients were found to have significantly lower odds of 90-day readmissions and minor adverse events (dysphagia), while rates of major adverse events (pulmonary embolism, deep vein thrombosis, sepsis, etc.) were comparable between the groups. Further CDA patients had lower cost of overall care, but no difference in five-year survival to cervical spine reoperation. Thus, it may be appropriate to further consider CDA when two-level surgery is pursued.

Five-year Follow-up of a Prospective Food and Drug Administration Investigational Device Exemption Trial Evaluating a PEEK-on-Ceramic Cervical Disc Replacement.

Prospective trial comparing the investigation group to propensity matched historic control group. To evaluate 5-year results of single-level PEEK-on-ceramic cervical total disc replacement (TDR) compared to a propensity matched anterior cervical discectomy and fusion (ACDF) control group. Cervical TDR has gained acceptance as treatment for symptomatic disc degeneration. The design and materials used in these devices continue to evolve. Data were collected in the Food and Drug Administration Investigational Device Exemption trial for the PEEK-on-ceramic Simplify(®) Cervical Artificial Disc (n=150) with comparison to a propensity matched ACDF control group (n=117). All patients were treated for single-level cervical disc degeneration with radiculopathy and/or myelopathy. Clinical outcome was based on composite clinical success (CCS), Neck Disability Index (NDI), visual analog scales (VAS) assessing pain, re-operations, and satisfaction. Radiographic measures included segmental range of motion (ROM), disc space height, and heterotopic ossification (HO). Evaluations were performed pre-operatively and post-operatively within 2 and 6 weeks, and 3, 6, 12 months, and annually thereafter. At 5-year follow-up, CCS was significantly greater with TDR than ACDF (91.1% vs. 74.6%; P<0.01). In the TDR group, the mean NDI score was 63.3 pre-operatively, reduced significantly to 23.1 at 6 weeks and remained below 20 throughout 5-year follow-up. In the ACDF group, the mean pre-operative NDI score was 62.4, decreasing to 33.7 at 6 weeks, and ranged from 25.9 to 21.5 throughout follow-up. Mean NDI scores were significantly lower in TDR group at all post-operative points (P<0.05). Mean TDR ROM was 7.3o pre-operatively and 10.1o at 5 years. Bridging HO occurred in 9%. With TDR, there were 6 re-operations (4.0%) vs. 11 (9.4%) with ACDF (P>0.40). PEEK-on-ceramic TDR produced significantly improved outcomes maintained throughout 5-year follow-up, were similar or superior to ACDF, supporting TDR in appropriately selected patients.

Outcomes of non-contiguous two-level anterior cervical discectomy and fusion in patients with degenerative cervical myelopathy: a retrospective study.

Non-contiguous two-level Anterior Cervical Discectomy and Fusion (ACDF) may be a viable option for patients with degenerative cervical myelopathy and imaging-evident spine and radicular compression at two non-contiguous cervical levels. The risk of hastening degeneration and triggering Adjacent Segment Disease at the spine levels located between the fused levels is a putative adverse event, which was assessed in a few studies. The aim of this study is to investigate the clinical outcomes of patients undergoing non-contiguous two levels ACDF and to assess biomechanical modifications at non-fused segments. We retrospectively reviewed all patients with noncontiguous two-level spine and radicular compression, who underwent simultaneous noncontiguous two-level ACDF at our center. We analyzed clinical and radiological outcomes and investigated the rate of adjacent segment disease. Radiographic parameters were calculated on pre- and postoperative images. Thirty-two patients underwent simultaneous noncontiguous two-level ACDF for cervical myelo-radiculopathy between 2015 and 2021 and were followed up for a mean period of 43.3 months. For all patients, the mJOA score significantly improved from 14.57 ± 2.3 to 16.5 ± 2.1 (p<0.01) and the NDI score significantly decreased from 21.45 ± 4.3 to 12.8 ± 2.3 (p<0.01) postoperatively. Cervical lordosis increased after surgery (from 9.65° ±9.47 to 15.12° ± 6.09); intermediate disc height decreased (5.68 mm ± 0.57 to 5.27 mm ±0.98); the ROMs of intermediate (from 12.45 ± 2.33 to 14.77 ± 1.98), cranial (from 14.63 ± 1.59 to 15.71 ± 1.02), and caudal (from 11.58 ± 2.32 to 13.33 ± 2.67) segments slightly increased. During follow-up assessment, in one patient the myelopathy worsened due to spine compression at the intermediate level. Simultaneous and non-contiguous two-level ACDF is a safe and effective procedure. The occurrence of postoperative adjacent and intermediate segment disease is rare.

Diagnosis of spine pseudoarthrosis based on the biomechanical properties of bone

BACKGROUND CONTEXTFailure to fuse following anterior cervical discectomy and fusion (ACDF) may result in symptomatic pseudoarthrosis. Traditional diagnosis involves computerized tomography to detect bridging bone and/or flexion-extension radiographs to assess whether segmental motion is above specific thresholds; however, there are currently no well-validated diagnostic tests. We propose a biomechanically rational approach to achieve a reliable diagnostic test for pseudoarthrosis. PURPOSEDevelop and test a biomechanically based approach to the diagnosis of pseudoarthrosis. STUDY DESIGNLiterature review, development of theory, re-analysis of a previously published study with surgical exploration as the gold-standard, and retrospective analysis of pooled studies to understand time to fusion. METHODSFully automated methods were used to measure disc space strains (change in disc space height divided by initial height). Measurement error combined with the reported failure strain of trabecular bone led to a proposed strain threshold for diagnosis of pseudoarthrosis following ACDF. We reanalyzed previously reported flexion-extension radiographs for asymptomatic volunteers to assess whether flexion-extension radiographs, in the absence of fusion surgery, can be expected to provide sufficient stress on motion segments to allow for reliable strain-based fusion assessment. The sensitivity and specificity of strain- and rotation-based pseudoarthrosis diagnosis were assessed by reanalysis of previously reported post-ACDF flexion-extension radiographs, where intraoperative fusion assessments were also available. Finally, we assessed changes in strain over time using 9,869 flexion-extension radiographs obtained 6 weeks to 84 months post-ACDF surgery from 1,369 patients. RESULTSThe estimated error in automated measurement of disc space strain from radiographs was approximately 3%, and the reported failure strain of bridging bone was less than 2.5%. On that basis, we propose a 5% strain threshold for pseudoarthrosis diagnosis. Reanalysis of a study in which intraoperative fusion assessments were available revealed 67% sensitivity and 82% specificity for strain-based diagnosis of pseudoarthrosis, which was comparable to rotation-based diagnosis. Analysis of post-ACDF flexion-extension radiographs revealed rapid strain reduction for up to 24 months, followed by a slower decrease for up to 84 months. When rotation is less than 2 degrees, the strain-based diagnosis differed from the rotation-based diagnosis in approximately 14% of the cases. CONCLUSIONSWe propose steps for standardizing diagnosis of pseudoarthrosis based on the failure strain of bone, measurement error, and retrospective data. These steps include obtaining high-quality flexion-extension studies, the application of proposed diagnostic thresholds, and the use of image stabilization for conclusive diagnosis, when motion is near thresholds. The necessity for an accurate diagnosis with minimal radiation exposure underscores the need for further optimization and standardization in diagnosing pseudoarthrosis following ACDF surgery. CLINICAL SIGNIFICANCEIn a symptomatic postspine fusion patient, it is important to diagnose or rule-out pseudoarthrosis. There are currently no well-validated diagnostic tests for this condition. Incorporating strain-based intervertebral motion analysis into the diagnosis could lead to a standardized and validated test for detecting spine pseudoarthrosis.

Implant Design and Cervical Spinal Biomechanics and Neurorehabilitation: A Finite Element Investigation.

The cervical spine, pivotal for mobility and overall body function, can be affected by cervical spondylosis, a major contributor to neural disorders. Prevalent in both general and military populations, especially among pilots, cervical spondylosis induces pain and limits spinal capabilities. Anterior Cervical Discectomy and Fusion (ACDF) surgery, proposed by Cloward in the 1950s, is a promising solution for restoring natural cervical curvature. The study objective was to investigate the impacts of ACDF implant design on postsurgical cervical biomechanics and neurorehabilitation outcomes by utilizing a biofield head-neck finite element (FE) platform that can facilitate scenario-specific perturbations of neck muscle activations. This study addresses the critical need to enhance computational models, specifically FE modeling, for ACDF implant design. We utilized a validated head-neck FE model to investigate spine-implant biomechanical interactions. An S-shaped dynamic cage incorporating titanium (Ti) and polyetheretherketone (PEEK) materials was modeled at the C4/C5 level. The loading conditions were carefully designed to mimic helmet-to-helmet impact in American football, providing a realistic and challenging scenario. The analysis included intervertebral joint motion, disk pressure, and implant von Mises stress. The PEEK implant demonstrated an increased motion in flexion and lateral bending at the contiguous spinal (C4/C5) level. In flexion, the Ti implant showed a modest 5% difference under 0% activation conditions, while PEEK exhibited a more substantial 14% difference. In bending, PEEK showed a 24% difference under 0% activation conditions, contrasting with Ti's 17%. The inclusion of the head resulted in an average increase of 18% in neck angle and 14% in C4/C5 angle. Disk pressure was influenced by implant material, muscle activation level, and the presence of the head. Polyetheretherketone exhibited lower stress values at all intervertebral disc levels, with a significant effect at the C6/C7 levels. Muscle activation level significantly influenced disk stress at all levels, with higher activation yielding higher stress. Titanium implant consistently showed higher disk stress values than PEEK, with an orders-of-magnitude difference in von Mises stress. Excluding the head significantly affected disk and implant stress, emphasizing its importance in accurate implant performance simulation. This study emphasized the use of a biofidelic head-neck model to assess ACDF implant designs. Our results indicated that including neck muscles and head structures improves biomechanical outcome measures. Furthermore, unlike Ti implants, our findings showed that PEEK implants maintain neck motion at the affected level and reduce disk stresses. Practitioners can use this information to enhance postsurgery outcomes and reduce the likelihood of secondary surgeries. Therefore, this study makes an important contribution to computational biomechanics and implant design domains by advancing computational modeling and theoretical knowledge on ACDF-spine interaction dynamics.

P184. Are patients with segmental cervical kyphosis appropriate candidates for cervical disc arthroplasty (CDA)? A clinical and radiographic analysis compared to anterior cervical discectomy and fusion (ACDF)

P184. Are patients with segmental cervical kyphosis appropriate candidates for cervical disc arthroplasty (CDA)? A clinical and radiographic analysis compared to anterior cervical discectomy and fusion (ACDF)

Prevertebral Soft-tissue Swelling Following One-level Anterior Cervical Discectomy and Fusion: An Analysis Based on Surgical Level.

The purposes of this study were to identify the primary level at which PSTS occurs following one level anterior cervical discectomy and fusion (ACDF) based on surgical level, and to quantify the degree to which it occurs. Although prevertebral tissue swelling (PSTS) peaks at day 2 or 3 after ACDF, with swelling noted to be prominent at levels C2-4, the way in which the features of PSTS vary according to surgical level has not been examined. 37 patients who underwent one-level ACDF were reviewed and classified into retropharyngeal and retrotracheal group based on surgical level. PSTS occurring at C2-C6 and the width of airway (WA) at C2-C4 was assessed using plain radiographs before surgery and at 1, 3, 5, and 7 days postoperatively. The retropharyngeal group comprised 10 patients while the retrotracheal group comprised 27 patients. Retropharyngeal group had the most severe PSTS on day 3 after surgery. C4 showed PSTS peaked on day 3, with a value of 3.26 times the preoperative prevertebral tissue thickness. WA at C4 was narrowest on day 1, with a value of 0.74 times and remained narrow until day 3. The retrotracheal group showed the most severe PSTS on day 1 at level C3:2.81 times. WA at C4 was narrowest on day 1 with a value of 0.78 times and increased thereafter. PSTS following one-level ACDF for both retropharyngeal and retrotracheal lesions was greatest at the C3 and C4 levels, with peaks on the third day after operation for the former, and the first day for the latter. WA at C4 was narrowest from day 1 in both groups. In the retrophyaryngeal group, narrowing remained until day 3.

Revisiting the Posterior Approach for Cervical Radiculopathy Utilizing Endoscopic Techniques: A Favorable Short-Term Outcome and Cost Comparison With Anterior Cervical Discectomy and Fusion.

Cervical radiculopathy is a spine ailment frequently requiring surgical decompression via anterior cervical discectomy and fusion (ACDF) or posterior foraminotomy/discectomy. While endoscopic posterior foraminotomy/discectomy is gaining popularity, its financial impact remains understudied despite equivalent randomized long-term outcomes to ACDF. In a cohort of patients undergoing ACDF vs endoscopic posterior cervical foraminotomy/discectomy, we sought to compare the total cost of the surgical episode while confirming an equivalent safety profile and perioperative outcomes. A single-center retrospective cohort study of patients with unilateral cervical radiculopathy undergoing ACDF or endoscopic cervical foraminotomy between 2018 and 2023 was undertaken. Primary outcomes included the total cost of care for the initial surgical episode (not charges or reimbursement). Perioperative variables and neurological recovery were recorded. Multivariable analysis tested age, body mass index, race, gender, insurance type, operative time, and length of stay. A total of 38 ACDF and 17 endoscopic foraminotomy/discectomy operations were performed. All patients underwent single-level surgery except for 2 two-level endoscopic decompressions. No differences were found in baseline characteristics and symptom length except for younger age (46.8 ± 9.4 vs 57.6 ± 10.3, P = 0.002) and more smokers (18.4% vs 11.8%, P = 0.043) in the ACDF group. Actual hospital costs for the episode of surgical care were markedly higher in the ACDF cohort (mean ±95% CI; $27,782 ± $2011 vs $10,103 ± $720, P < 0.001) driven by the ACDF approach (β = $17,723, P < 0.001) on multivariable analysis. On sensitivity analysis, ACDF was never cost-efficient compared with endoscopic foraminotomy, and endoscopic failure rates of 64% were required for break-even cost. ACDF was associated with significantly longer operative time (167.7 ± 22.0 vs 142.7 ± 27.4 minutes, P < 0.001) and length of stay (1.1 ± 0.5 vs 0.1 ± 0.2 days, P < 0.001). No significant difference was found regarding 90-day neurological improvement, readmission, reoperation, or complications. Compared with patients treated with a single-level ACDF for unilateral cervical radiculopathy, endoscopic posterior cervical foraminotomy/discectomy can achieve a similar safety profile, pain relief, and neurological recovery at considerably less cost. These findings may help patients and surgeons revisit offering the posterior cervical foraminotomy/discectomy utilizing endoscopic techniques. Endoscopic posterior cervical foraminotomy/discectomy offers comparable safety, pain relief, and neurological recovery to traditional methods but at a significantly lower cost.

The incidence, clinical features and risk factors for postoperative retropharyngeal hematoma and related dyspnea following anterior cervical discectomy and fusion: a single-center study of 10615 patients

BACKGROUND CONTEXTPostoperative retropharyngeal hematoma (PRH) and related dyspnea are rare but life-threatening complications following anterior cervical discectomy and fusion (ACDF) that require urgent recognition and treatment. However, current knowledge of PRH after ACDF is limited. Meanwhile, whether the morphological features of upper airway are the risk factors of PRH remains unknown. PURPOSEThe study aimed to investigate the incidence, clinical features, and risk factors, especially the morphological features of upper airway, of PRH and related dyspnea following ACDF. STUDY DESIGNA nested case‒control study. PATIENT SAMPLEConsecutive patients who underwent ACDF at a single institute from January 2010 to December 2021 were retrospectively reviewed. OUTCOME MEASURESThe outcome measures included the incidence, clinical features, intervention, outcome and risk factors for PRH and related dyspnea. METHODSAll patients with PRH were classified into the hematoma group. For each PRH subject, 3 control subjects without PRH were randomly selected as the control group. The clinical features, interventions and outcomes of patients were described. Potential risk factors were evaluated, including demographics, comorbidities, surgical characteristics, coagulation function, blood loss, preoperative blood pressure, and the morphological features of upper airway [prevertebral soft tissue thickness (PVT) and location of transverse arytenoid muscle (TAM) and epiglottis]. Univariate tests and multivariable logistic regression analysis were used to determine the risk factors for PRH. Subgroup analysis was also conducted for PRH patients with and without dyspnea. RESULTSAmong the 10615 patients who underwent ACDF, 18 (0.17%) developed PRH. The median time from the index surgery to PRH formation was 8.5 hours (25 and 75 percentile: 4 hours to 24 hours). All the PRH patients initially presented with wound swelling. Twelve (0.11%) patients presented dyspnea due to PRH, 2 of whom received urgent intubation and 1 of whom received emergent tracheotomy. All patients underwent hematoma evacuation, and most of them presented with completely relieved symptoms after evacuation, except for 1 patient who died from ischemic hypoxic encephalopathy. A level between the epiglottis and the TAM (LET) greater than 2, ossification of posterior longitudinal ligament (OPLL) and higher diastolic blood pressure (DBP) before surgery were found to be risk factors for PRH formation. Subgroup analysis revealed that a smaller prevertebral soft tissue thickness at C5 was associated with the development of dyspnea. CONCLUSIONThis study is the largest study to date focusing on the PRH and related dyspnea after ACDF. Our study showed that the incidences of PRH and related dyspnea after ACDF were 0.17% and 0.11%, respectively. The predominant symptoms of PRH were wound swelling and acute dyspnea. Most PRH cases occurred in the acute postoperative period. We demonstrated the risk factors for PRH to be (1) OPLL, (2) LET≥2 and (3) higher DBP before surgery and advocate paying increased attention to upper airway morphological features for identifying the risk of PRH after ACDF. With urgent recognition and timely intervention, severe clinical outcomes could be avoided.

A Meta-Analysis of Surgical Outcomes in 25727 Patients Undergoing Anterior Cervical Discectomy and Fusion or Anterior Cervical Corpectomy and Fusion for Cervical Deformity.

Systematic Review. To evaluate which cervical deformity correction technique between anterior cervical discectomy and fusion (ACDF) and anterior cervical corpectomy and fusion (ACCF) produces better clinical, radiographic, and operative outcomes. We conducted a meta-analysis comparing studies involving ACDF and ACCF. Adult patients with either original or previously treated cervical spine deformities were included. Two independent reviewers categorized extracted data into clinical, radiographic, and operative outcomes, including complications. Clinical assessments included patient-reported outcomes; radiographic evaluations examined C2-C7 Cobb angle, T1 slope, T1-CL, C2-7 SVA, and graft stability. Surgical measures included surgery duration, blood loss, hospital stay, and complications. 26 studies (25727 patients) met inclusion criteria and were extracted. Of these, 14 studies (19077 patients) with low risk of bias were included in meta-analysis. ACDF and ACCF similarly improve clinical outcomes in terms of JOA and NDI, but ACDF is significantly better at achieving lower VAS neck scores. ACDF is also more advantageous for improving cervical lordosis and minimizing the incidence of graft complications. While there is no significant difference between approaches for most surgical complications, ACDF is favorable for reducing operative time, intraoperative blood loss, and length of hospital stay. While both techniques benefit cervical deformity patients, when both techniques are feasible, ACDF may be superior with respect to VAS neck scores, cervical lordosis, graft complications and certain perioperative outcomes. Further studies are recommended to address outcome variability and refine surgical approach selection.

Biomechanical Effects on the Prostheses and Vertebrae of Three-Level Hybrid Surgery: A Finite Element Study.

Three-level hybrid surgery (HS) consisting of cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF) has been partly used for the treatment of multi-level cervical degenerative disc disease (CDDD). The complications related to the implants and the collapse of the surgical vertebral bodies had been reported in multi-level anterior cervical spine surgery. Thus, this study aimed to explore the biomechanical effects on the prostheses and vertebrae in three-level HS. A FE model of cervical spine (C0-T1) was constructed. Five surgical models were developed. They were FAF model (ACDF-CDA-ACDF), AFA model (CDA-ACDF-CDA), FFF model (three-level ACDF), SF model (single-level ACDF), and SA model (single-level CDA). A 75-N follower load and 1.0-N·m moment was applied to produce flexion, extension, lateral bending, and axial rotation. Compared with the intact model, the range of motion (ROM) of total cervical spine in FAF model decreased by 34.54%, 54.48%, 31.76%, and 27.14%, respectively, in flexion, extension, lateral bending, and axial rotation, which were lower than those in FFF model and higher than those in AFA model. The ROMs of CDA segments in FAF and AFA models were similar to the intact model and SA model. Compared with the intact model, the ROMs at C3/4 segment in FFF model increased from 5.71% to 7.85%, and increased from 5.31% to 6.81% at C7/T1 segment, following by FAF model, then the FAF model. The maximum interface pressures of the Prestige-LP in FAF model were similar to SA model, however the corresponding values were increased in AFA model. The maximum interface pressures of the Zero-P were increased in FAF and AFA model compared with those in SF and FFF models. The stress was mainly distributed on the screws. In AFA model, the maximum pressures of the ball and trough articulation in superior and inferior Prestige-LP were all increased compared with those in SA and FAF model. In FFF model, the maximum pressures of the vertebrae were higher than those in other models. The stress was mainly distributed on the anterior area of the vertebral bodies. HS seemed to be more suitable than ACDF for the surgical treatment of three-level CDDD in consideration of the biomechanical effects, especially for the two-level CDA and one-level ACDF construct. But a more appropriate CDA prosthesis should be explored in the future.

Postoperative Horner Syndrome: A Case Report Describing a Rare Complication After Anterior Cervical Discectomy and Fusion

The gold standard for correcting cervical degenerative disc disease (CDDD) is anterior cervical discectomy and fusion (ACDF), which is a safe, effective procedure. Horner syndrome (HS) is an extremely rare complication immediately post-ACDF due to impairment of the sympathetic trunk. Herein, we present the case of a 48-year-old woman with CDDD-related pain and radiculopathy who was counselled and consented for C5–6 and C6–7 ACDF. ACDF was performed with standard anterior left-sided incisions at appropriate levels. Unlike our usual practice, deeper-toothed retractors were employed for better exposure. Two cages were inserted at C5–6 and C6–7. The procedural time was standard (180 minutes), without intraoperative complications. The patient experienced significant symptom relief immediately post-ACDF, but developed sudden onset left-sided HS, with ptosis, miosis, and anhidrosis, approximately 48 hours post-ACDF. At a 2-week postoperative follow-up, she exhibited clinical improvement, and by 12 weeks, her HS had completely resolved. To our knowledge, this case is the first documented instance of delayed-onset HS post-ACDF. It may be associated with the type of retractors used, resulting in neuropraxia or strain on the sympathetic chain ganglia. We recommend adequate exposure while minimizing excessive retraction of the longus colli muscle to reduce irritation to the sympathetic trunk.

Does Spinal Cord-Canal Mismatch Adversely Affect the Clinical Outcomes of Anterior Cervical Discectomy and Fusion for the Treatment of Cervical Myelopathy?

Retrospective cohort study. To clarify whether clinical outcomes of anterior cervical discectomy and fusion (ACDF), is affected by presence of spinal canal-cord mismatch (SCCM). SCCM is considered a factor that would moderately influence surgeons to perform posterior surgery since it could widen the spinal canal, while an anterior approach could only remove degenerative pathologies grown into the spinal canal. We retrospectively reviewed 186 patients who underwent ACDF and had been followed-up for >2 years. Patients with spinal cord occupation ratio (SCOR) of ≥0.7 were classified into the SCCM group, while those with a SCOR of <0.7 were included in the no-SCCM group. Patient demographics, cervical sagittal parameters, neck pain visual analog scale (VAS), arm pain VAS, and Japanese Orthopedic Association (JOA) score were assessed. JOA score was the primary outcome of the study. One-hundred and forty-seven patients (79.0%) were included into the no-SCCM group, while 39 patients (21.0%) were classified into the SCCM group. Postoperative radiographic parameters including C2-C7 lordosis, C2-C7 sagittal vertical axis, and range of motion did not significantly differ between the two groups. Neck pain VAS, arm pain VAS, and JOA score (no-SCCM group, from 13.7±2.5 to 14.6±2.3, P<0.001; SCCM group, from 13.8±1.6 to 15.0±2.0, P<0.001) significantly improved after the operation in both groups, and results were not significantly different between the two groups. Furthermore, SCOR was not significantly associated with JOA recovery rate at 2 years postoperatively in linear regression analysis. Clinical and radiographic outcomes of ACDF were not affected by the presence of SCCM. Furthermore, SCOR was not significantly associated with neurologic recovery at 2 years of follow-up. Therefore, ACDF can be safely and effectively applied for treating cervical myelopathy, regardless of the presence of SCCM, when other factors favor the anterior approach. 3.

Study on the consistency between CT hounsfield units and MRI evaluation of preoperative cervical paraspinal muscular fat infiltration in patients undergoing ACDF

ObjectiveTo explore the feasibility of applying CT Hounsfield Units (HUs) for the assessment of preoperative paraspinal muscle fat infiltration (FI) in different segments in patients who underwent anterior cervical discectomy and fusion (ACDF). To compare the consistency of preoperative paraspinal muscle FI evaluations using MRI and those via CT HUs in patients who underwent ACDF surgery.MethodsNinety-five patients (45 males and 50 females, aged 37‒71 years) who received CT and MRI examinations and underwent ACDF surgery were retrospectively analyzed. In the axial T2-weighted MR images at the median level of the C3/4, C4/5, and C5/6 segments, regions of interests (ROIs) were delineated along the boundaries of the cervical multifidus (MF) and semispinalis cervicis (Scer) muscles. Using the threshold tool in ImageJ software, areas of fat tissue and intermuscular septa within the ROI were quantified. The effective cross-sectional area (ECSA) for each side was obtained by subtracting the areas of fat tissue and intermuscular septa from the total ROI area. The ratio of the fat tissue area to the CSA was then calculated to determine the initial FI value. The depth of subcutaneous fat from the midline spinous process to the epidermis at the median plane of the C4/5 intervertebral disc was measured. The initial FI values were then divided by the depth of fat to determine the post-correction FI value. Using the Picture Archiving and Communication System (PACS), at identical segments and planes, ROIs were delineated using the same method as in MRI under a standard soft tissue window (width of 500 HU, level of 60 HU). The CT HU values were measured within these defined areas. The CT HU values from both sides are summed to obtain the total HU value for the segment. According to whether the measurement results of two sets of data follow a normal distribution, Pearson’s test or Sperman’s test was used to analyze the correlation.ResultsOn MRI, a statistically significant difference was observed in the post-correction FI only at the C3/4 segment compared to the other two segments (P < 0.05). No significant difference in the post-correction FI between the C4/5 and C5/6 segments was noted (P > 0.05). The CT HU results showed a substantial discrepancy between C3/4 and C4/5 segments and between C3/4 and C5/6 segments (P < 0.05), whereas no statistically significant difference was found in the CT HU value between the C4/5 and C5/6 segments (P > 0.05). The consistency analysis revealed a relatively strong correlation between the post-correction FI and CT HU values of the C3/4 and C4/5 segments. Furthermore, a strong correlation was detected in the variations in the measurement outcomes at the C5/6 segment.ConclusionPatients requiring surgical treatment for the cervical spine exhibit varying degrees of FI in paraspinal muscles across different locations and segments. Evaluating the degree of FI in the paraspinal muscles of the cervical spine through CT HU values is feasible. There is considerable consistency between the post-correction FI assessed under MRI and the measurements of CT HU values in evaluating the FI of paraspinal muscles in the cervical spine.