Update of the Natural History, Pathophysiology, and Treatment Strategies of Degenerative Cervical Myelopathy: A Narrative Review

A Systematic Review of Current Terminology for Conditions Preceding Degenerative Cervical Myelopathy: Evidence Synthesis to Inform an AO Spine Expert Opinion Statement

Study DesignSystematic review.ObjectivesThe pre-symptomatic state of Degenerative Cervical Myelopathy (DCM), wherein degenerative changes and spinal cord compression are seen without clinical findings, is poorly understood and inconsistently categorised. Clear identification may elucidate the temporality of DCM development. Therefore, a systematic assessment was undertaken of current terminology for pre-DCM states, with the objective of standardising definitions and informing an AO Spine expert position statement.MethodsMedline and Embase were searched for all studies on asymptomatic spinal compression or clinical findings preceding DCM, returning 3585 studies. After screening, 96 studies were included in the final analysis. The terminology used for pre-DCM states and their definitions were extracted, along with their frequencies or speciality/country of author in the literature.ResultsMultiple terms were used to represent pre-DCM stages, including "asymptomatic" (86 studies), "non-myelopathic" (26 studies), "without myelopathy" (15 studies), "pre-symptomatic" (9 studies) and "sub-clinical" (7 studies). "asymptomatic" was associated with the greatest inconsistency. Some defined this as patients with radiological signs of spinal degeneration with/without spinal cord compression but no clinical signs of myelopathy, whereas others used the term synonymously with healthy controls. This inconsistency is particularly challenging in clinical studies in which DCM patients are compared to those with pre-DCM states and/or healthy volunteers.ConclusionThere is substantial inconsistency in the terms used to describe pre-DCM states. There is no clear relationship between the terms used and the country or speciality of the main author. Standardised definitions for these disease states should be agreed and used in future studies.

Myokinetic Stretching Exercise Versus Post-Isometric Relaxation Combined with Traction in Patients with Cervical Radiculopathy-A Randomized Clinical Trial

BACKGROUND

Cervical radiculopathy is one of the frequent musculoskeletal problems prevalent in the general population, characterized by neck pain radiating to the upper limb. This study investigated the effects of the myokinetic stretching technique versus post-isometric relaxation (PIR) exercises with mechanical traction in patients with cervical radiculopathy.

METHODS

A single-blinded, randomized clinical trial was conducted from March 2023 to June 2023. Sixty-six patients with cervical radiculopathy were randomly assigned to two groups: Group A (n = 33) received myokinetic stretching exercises and Group B (n = 33) received isometric relaxation exercises, while mechanical cervical traction was applied to both groups as the baseline treatment. The treatment frequency was two sessions per week for eight weeks. Outcome measures were pain, range of motion, and neck disability measured through the Numerical Pain Rating Scale, a goniometer, and the Urdu version of the Neck Disability Index. Assessments were performed at the baseline and the 4th and 8th weeks of the treatment.

RESULTS

The between-group analysis showed a non-significant difference (p > 0.05). The within-group analysis showed (p < 0.001) significant improvement in both groups.

CONCLUSION

This study concluded that the myokinetic stretching technique and post-isometric relaxation exercises combined with mechanical traction are effective in improving pain, range of motion, and neck disability in patients with cervical radiculopathy.

Removal of Retro-Corporeal Compressive Pathology Using Guttering Osteotomy During Anterior Cervical Discectomy and Fusion

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

Guttering is a technique that creates a tunnel through the vertebral body adjacent to the endplate to remove compressive pathologies behind the vertebral body during anterior cervical discectomy and fusion (ACDF). In this study, we investigated cases of patients who underwent gutter-shaped osteotomy (guttering) to decompress retro-corporeal compressive lesions.

SUMMARY OF BACKGROUND DATA

Retro-corporeal pathologies causing cord compression cannot be removed using conventional ACDF.

MATERIALS AND METHODS

A total of 217 patients who underwent ACDF to treat cervical myelopathy and were followed up for ≥1 year were retrospectively reviewed. The fusion rate, subsidence, neck pain visual analog scale (VAS), arm pain VAS, and neck disability index (NDI) were assessed. Results were compared between the guttering (patients for whom guttering was performed) and nonguttering (patients for whom guttering was not performed) groups.

RESULTS

Thirty-five patients (16.1%) were included in the guttering group, while 182 patients (83.8%) were included in the nonguttering group. Fusion rates assessed by interspinous motion ( P =0.559) and bone bridging on computed tomography (CT) ( P =0.541 and 0.715, respectively) were not significantly different between the 2 groups at 1 year after surgery. Furthermore, neck pain VAS ( P =0.492), arm pain VAS ( P =0.099), and NDI ( P =1.000) 1 year after surgery did not demonstrate significant intergroup differences. All patients in the guttering group exhibited healed guttering on 1-year postsurgery CT.

CONCLUSIONS

Guttering as an adjunct to ACDF could provide a more expansive workspace for complete decompression when compressive pathology extends retrocorporeal. This additional bone resection is not associated with increased pseudarthrosis or subsidence or related to aggravation of patient symptoms.

LEVEL OF EVIDENCE

Level III.

Novel radiologic parameter for assessing decompression adequacy in anterior cervical decompression surgery: the V-line

BACKGROUND CONTEXT

Anterior cervical decompression surgeries, such as Vertebral Body Sliding Osteotomy (VBSO) and Anterior Cervical Corpectomy and Fusion (ACCF), serve as vital surgical options for managing cervical myelopathy. Despite their effectiveness, incomplete expansion of the spinal canal can occur in certain cases. However, many patients still experience positive clinical outcomes after these surgeries, suggesting that assessing outcomes based solely on the lesion's canal-occupying effect may be limited. In cases of anterior-based fusion surgery, changes in cervical alignment can occur postoperatively. Since traditional measures like the canal occupying ratio (COR) consider only the absolute size of the lesion, they may overlook improvements in clinical symptoms due to enhanced lordosis.

PURPOSE

This study introduces the V-line, a novel radiologic parameter, to universally evaluate decompression outcomes in these procedures.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

This retrospective analysis encompassed 93 patients treated for cervical myelopathy due to ossification of the posterior longitudinal ligament through either VBSO (N=76) or ACCF (N=17) OUTCOME MEASURE: Radiological evaluations included C2-7 lordosis, segmental lordosis, and COR. The Japanese Orthopedic Association (JOA) scores were assessed preoperatively, at 1-year postoperatively, and at the final follow-up.

METHODS

The V-line, defined on a plain lateral radiograph in the neutral position, connects the lowest point on the posterior margin of the vertebral body immediately above the osteotomy site to the highest point on the posterior margin immediately below it. The V-line classification was "V-line (-)" if the postoperative pathologic lesion contacted the V-line and "V-line (+)" if it did not. Patients were categorized based on postoperative COR and the V-line assessment.

RESULTS

The V-line (+) group achieved a higher final JOA score (15.3±1.91) and JOA recovery rate (62.16±32.22) compared to the V-line (-) group, which recorded a final JOA score (14.25±2.33, p=.037) and a JOA recovery rate (24.71±32.00, p<.001). Additionally, postoperative C2-7 lordosis (18.05±9.59, p<.001) and segmental lordosis (18.53±8.49, p=.008) in the V-line (+) group were significantly greater than in the V-line (-) group (10.68±8.38; 11.42±7.87). However, when comparing groups based on postoperative COR, significant differences were observed only in the JOA recovery rate, with no notable differences in final JOA score, C2-7 lordosis and segmental lordosis between the groups.

CONCLUSIONS

Since the V-line accounts for both the mass effect of the pathological lesion and cervical alignment, this parameter effectively reflects the reduced impact of spinal cord compression when cervical lordosis is restored, even with residual canal-occupying lesions present. These findings underscore the importance of considering changes in alignment, not just the reduction in lesion size, in assessing decompression adequacy. Therefore, the V-line provides a more comprehensive measure of decompression adequacy than the traditional COR, which may fail to capture the clinical significance of changes in postoperative spinal alignment.

Automatic Pavlov ratio measurement method based on spinal landmarks identification by a deep-learning model

BACKGROUND

Cervical canal stenosis is one of the important pathogenic factors of cervical spondylosis. The accuracy of the Pavlov ratio measurement is crucial for the diagnosis and treatment of cervical spinal stenosis. Manual measurement is influenced by observer variability, accompanied by its inefficiency, which affects clinical evaluation.

PURPOSE

To automatically and accurately measure the Pavlov ratio, we develop a novel deep-learning model by detecting keypoints of cervical spine and measure the Pavlov ratio on plain lateral cervical spine radiographs.

METHODS

We developed a two-stage deep-learning model; in the first stage, we employ the YOLOX model as the object detection network to locate the ROIs containing the vertebral bodies and spinous processes; in the second stage, we introduce the high-resolution net (HRNet) as keypoint detection network and a series of deconvolutional networks (DNs) as the heatmap-based regressor. Based on the mentioned combining algorithms, we can rapidly detect the 38 keypoints in plain lateral cervical spine radiographs, and then measure the Pavlov ratio of the cervical spine. Radiographs from Shanghai Changhai Hospital (a total of 874) were split into training and test subsets (787 and 87 radiographs, respectively). One hundred twelve cases from Shanghai Changzheng Hospital and 108 cases from Shanghai Fourth People's Hospital are used as external validation datasets.

RESULTS

Our proposed model successfully achieved the objective of automating the recognition of spinal landmarks with the mean absolute error (MAE)ranged from 0.05 to 0.08, and the symmetric mean absolute percentage error (SMAPE) ranged from 4.54% to 6.43%. The achieved accuracy is comparable to that of seasoned medical professionals and notably surpasses the performance of junior physicians (SMAPE ranged from 8.74% to 26.19%). Furthermore, our model demonstrated excellent accuracy in external validation experiments (SMAPE ranged from 4.40% to 5.95%).

CONCLUSION

This study presents a novel YOLOX-HRNet-DN model to assist landmarks identification on lateral cervical spine radiographs and demonstrates excellent accuracy in measuring the Pavlov ratio. The proposed method could provide a potential tool for the automatic estimation of the Pavlov ratio to improve the efficiency and accuracy of the treatment workflow.

Atrophy of the Posterior Cricoarytenoid Muscle as an Indicator of a Recurrent Laryngeal Nerve Injury History Before Revision Anterior Cervical Spine Surgery

STUDY DESIGN

Retrospective study.

OBJECTIVES

In our recent study, we observed some cases of symptomatic normal vocal cord motility instead of asymptomatic vocal cord palsy (VCP) in preoperative laryngoscopy of a revision anterior cervical spine surgery (ACSS) cohort. We assumed the intrinsic muscle atrophy caused by recurrent laryngeal nerve injury could cause vocal cord-related symptoms. Thus, radiological examinations were reviewed in relation to the posterior cricoarytenoid (PCA) muscle, one of the intrinsic muscles.

METHODS

We retrospectively analyzed 64 patients who underwent a revision ACSS. Patients with vocal cord-related symptoms were classified as symptomatic group (group S, n = 11), and those without symptoms as asymptomatic group (group AS, n = 53). The bilateral size and signal intensity of the PCA muscles in these patients were measured in the axial view with preoperative computed tomography (CT) and magnetic resonance imaging (MRI) evaluations. Since the size and signal intensity values were different on each image, the ratios of the contralateral and ipsilateral muscle values were analyzed for each modality.

RESULTS

There was no VCP on laryngoscopy study. However, the mean ratio of the PCA muscle size on CT was 1.40 ± .37 in group S and 1.02 ± .12 in group AS (P = .007). These values on the MRI were 1.49 ± .45 in group S and 1.02 ± .14 in group AS, which was also a significant difference (P = .008).

CONCLUSIONS

Evaluating the size of the PCA muscle before revision ACSS may predict a previous recurrent laryngeal nerve injury. Careful planning for the appropriate approach should be undertaken if vocal cord-related symptoms and atrophy of PCA muscle are evident.

Reoperation Rates According to Surgical Approach After Operation for Degenerative Cervical Pathology in Patients With Athetoid Cerebral Palsy: A Nationwide Cohort Study

STUDY DESIGN

National population-based cohort study.

OBJECTIVE

The overall complication rate for patients with athetoid cerebral palsy (CP) undergoing cervical surgery is significantly higher than that of patients without CP. The study was conducted to compare the reoperation and complication rates of anterior fusion, posterior fusion, combined fusion, and laminoplasty for degenerative cervical myelopathy/radiculopathy in patients with athetoid cerebral palsy.

METHODS

The Korean Health Insurance Review and Assessment Service national database was used for analysis. Data from patients diagnosed with athetoid CP who underwent cervical spine operations for degenerative causes between 2002 and 2020 were reviewed. Patients were categorized into four groups for comparison: anterior fusion, posterior fusion, combined fusion, and laminoplasty.

RESULTS

A total of 672 patients were included in the study. The overall revision rate was 21.0% (141/672). The revision rate was highest in the anterior fusion group (42.7%). The revision rates of combined fusion (11.1%; hazard ratio [HR], .335; P = .002), posterior fusion (13.8%; HR, .533; P = .030) were significantly lower than that of anterior fusion. Revision rate of laminoplasty (13.1%; HR, .541; P = .240) was also lower than anterior fusion although the result did not demonstrate statistical significance.

CONCLUSION

Anterior fusion presented the highest reoperation risk after cervical spine surgery reaching 42.7% in patients with athetoid CP. Therefore, anterior-only fusion in patients with athetoid CP should be avoided or reserved for strictly selected patients. Combined fusion, with the lowest revision risk at 11.1%, could be safely applied to patients with athetoid CP.

Construction of a nomogram for predicting the prognosis of patients with cervical spondylotic myelopathy: a retrospective study

Cervical spondylotic myelopathy (CSM) is a neurological disorder characterized by degenerative changes in the spinal cord and compression of the spinal cord and its adjacent structures due to various reasons, such as intervertebral disc herniation. The Japan Orthopaedic Association score is a disease-specific outcome tool that provides quantitative measurements for CSM patients. At present, no scholars have developed a model that can directly predict the prognosis of CSM patients. This study used binary logistic regression analysis to identify clinical independent predictive factors, and then used R language to construct a nomogram. The results showed that Hb (0.71 [0.51, 0.99]), LYM (0.32 [0.22, 0.46]), and ALB (0.32 [0.23, 0.45]) were independent predictive factors. Good prediction performance with modest errors was shown by the nomogram in both the training and validation groups. Hb, LYM, ALB are independent predictors of the prognosis of ACDF in CSM patients. The constructed nomogram can help clinicians assess and treat patients early, benefiting more patients.

Protein Kinase C and Matrix Metalloproteinases Expression Using Phorbol Myristate Acetate in Degenerative Intervertebral Disc Cells

Background

Degeneration of nucleus pulposus (NP) cells involves multiple factors. The relationship between the canonical Wnt/β-catenin signaling pathway and matrix metalloproteinases (MMPs) is important in cellular senescence. Protein kinase C (PKC), an intermediate of the non-canonical Wnt pathway stimulated by phorbol myristate acetate (PMA), possibly prevents NP cell senescence, although not yet demonstrated in human-based studies. This study aimed to investigate the effect of PMA stimulation on the non-canonical and canonical Wnt pathways and MMP expression in human NP cells to ascertain its inhibitory effects on the senescence of NP cells.

Methods

Human disc tissues of Pfirrmann grades 1 and 2 were collected from patients during spinal surgery and subsequently cultured. Protein and ribonucleic acid (RNA) were isolated from NP cells treated with PMA (400 nM) for 24 hours. Expression of MMP1, MMP13, tissue inhibitor of matrix metalloproteinase 1 (TIMP1), a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5), transient receptor potential vanilloid 4 (TRPV4), interleukin-6 (IL-6), and β-catenin were detected using western blot analysis. Messenger RNA (mRNA) expression of type II collagen and glycosaminoglycan (GAG) were analyzed using reverse transcription polymerase chain reaction. IL-6 and prostaglandin E2 (PGE2) levels were measured using enzyme-linked immunosorbent assay.

Results

Expression of PKC-δ (intermediate of the non-canonical Wnt pathway) and β-catenin (intermediate of the canonical Wnt pathway) was increased by PMA treatment. The mRNA levels of type II collagen and GAG increased; however, their protein levels were not altered. PMA treatment increased the expression of MMP1, TIMP1, ADAMTS5, IL-6, PGE2, and TRPV4; however, the expression of MMP13 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) was unaltered.

Conclusions

PMA activated PKC-δ, affecting the non-canonical Wnt pathway; however, its effect on β-catenin in the canonical Wnt pathway was limited. β-catenin activation through the TRPV4 channel led to increased expression of MMP1 and ADAMTS5 and that of IL-6 and PGE2 owing to NF-κB expression. Consequently, the degeneration of NP cells was not prevented.

Preoperative Factors on Loss of Range of Motion after Posterior Cervical Foraminotomy

Background and Objectives: Posterior cervical foraminotomy (PCF) aims to resolve cervical radiculopathy while preserving range of motion (ROM). However, its effectiveness in maintaining ROM is uncertain. This study investigates the changes in ROM after PCF and identifies preoperative factors that influence ROM reduction post surgery. Materials and Methods: This retrospective cohort study included patients treated at our hospital from August 2016 to September 2021. Clinical outcomes were assessed using the visual analog scale (VAS) for neck and arm pain and the neck disability index (NDI). Radiological outcomes included the segmental angle (SA), cervical angle (CA), C2-C7 SVA, Pfirrmann grade, extent of facetectomy, foraminal stenosis, and ROM. Patients were categorized into two groups based on segmental ROM changes: decreased (Group D) and maintained (Group M). Radiological and clinical outcomes were compared between the groups. Univariate and multivariate regression analyses were performed to identify risk factors for ROM loss after PCF. Results: 76 patients were included: 34 in Group D and 42 in Group M, with no demographic differences. Preoperatively, Group D had significantly larger flexion segmental and cervical angles than Group M (segmental, p < 0.001; cervical, p = 0.001). Group D also had a higher Pfirrmann grade (p = 0.014) and more bony bridge formations (p = 0.004). While no significant differences were observed in arm pain VAS and NDI scores, Group D exhibited worse neck pain VAS at the last follow-up (p = 0.03). Univariate linear regression indicated that preoperative segmental ROM (p < 0.001, B = 0.82) and bony bridge formation (p = 0.046, B = 5.33) were significant predictors of ROM loss post PCF. Conclusions: Patients with higher preoperative flexion angles and Pfirrmann grades at the operative level are at an increased risk for ROM loss and neck pain and often exhibit bony bridge formation. Accounting for these factors can improve surgical planning and patient outcomes.

Laminoplasty with foraminotomy versus anterior cervical discectomy and fusion for cervical myeloradiculopathy

BACKGROUND CONTEXT

Anterior cervical discectomy and fusion (ACDF) combined with uncinate process resection and laminoplasty combined with foraminotomy (LPF) have been used to achieve cervical cord and root decompression in patients with combined cervical myeloradiculopathy (CMR).

PURPOSE

To compare the clinical and radiographic outcomes of ACDF with those of LPF for the treatment of CMR.

STUDY DESIGN/SETTING

Propensity score-matched retrospective cohort study.

PATIENT SAMPLE

Patients with CMR who underwent ACDF or LPF and were followed up for at least 2 years.

OUTCOME MEASURES

C2-C7 lordosis, C2-C7 sagittal vertical axis, and cervical range of motion (ROM) were determined. The visual analog scale (VAS) scores for neck and arm pain, neck disability index (NDI), and Japanese Orthopedic Association (JOA) scores were analyzed.

METHODS

The radiographic and clinical outcomes of the 2 groups were compared.

RESULTS

Eighty-four patients were included (n=42 in each group) after application of the inclusion criteria and propensity score matching. A significant decrease in C2-C7 lordosis (p<.001) and ROM (p<.001) was observed in the LPF and ACDF groups, respectively. LPF was associated with a significant decrease in C2 to C7 lordosis (p<.001), while ACDF caused a significant decrease in cervical ROM (p<.001). ACDF effectively improved neck pain VAS (p<.001) and NDI (p<.001), while neck pain did not significantly improve after LPF (p=.103). Furthermore, neck pain VAS (p=0.026) and NDI (p=.021) at postoperative 6 months, were significantly greater in the LPF group than in the ACDF group, while the difference was not statistically significant at 2 years postoperatively (neck pain VAS, p=.502; NDI, p=.085). Arm pain VAS and JOA score both significantly improved after LPF (p=0.003 and 0.043, respectively) or ACDF (p<.001 and 0.039, respectively), and postoperative results were not significantly different between the 2 groups.

CONCLUSION

LPF and ACDF yielded similar outcomes for arm pain and neurological recovery. More immediate neck pain improvement was observed with ACDF, while neck pain after 2 years postoperatively was similar between the LPF and ACDF groups. Furthermore, increased postoperative loss of lordosis was observed in the LPF group, whereas decreased postoperative ROM was observed in the ACDF group. These findings should be considered when deciding the surgical method for patients with CMR.

LEVEL OF EVIDENCE

III.

Different Neurogenic Bladders in Patients with Cervical and Thoracic Myelopathy: Direct Comparison from a Prospective Case Series

Background/Objectives: This study aimed to identify the unique characteristics of neurogenic bladders and associated symptoms in patients with cervical or thoracic myelopathy using clinical surveys and urodynamic studies (UDSs). Methods: Patients with degenerative cervical (DCM) or thoracic (DTM) myelopathy and lower urinary tract symptoms (LUTSs) scheduled for decompressive surgery were prospectively enrolled. A UDS was performed one day preceding surgery to evaluate the preoperative urological function. Subjective symptoms were evaluated using the International Prostate Symptom Score (IPSS) and the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire before surgery and one year postoperatively. Results: Sixty-two patients (DCM: 50, DTM: 12) with a mean age of 63.2 years (men: 30, women: 32) were enrolled. The UDS revealed that 5 (8.1%) patients, all with DCM, exhibited completely normal UDS results, and the remaining 57 had at least one abnormal finding. Based on the International Continence Society classification, an underactive bladder was significantly more common in patients with DTM compared to patients with DCM (75.0% vs. 18.0%, p < 0.001). The results of the questionnaire showed that the voiding symptom IPSS were significantly worse, preoperatively, in patients with DTM (5.0 ± 4.4 [DCM] vs. 8.7 ± 4.5 [DTM]; p = 0.013). One year postoperatively, the IPSS grade of 24.0% of patients with DCM improved, whereas only one (8.3%) patient with DTM showed improvement. Conclusions: Patients with DTM reported worse voiding symptoms and exhibited more underactive bladders on UDS than patients with DCM before decompression. One year postoperatively, more patients with DCM showed subjective improvements in urinary function than those with DTM.

The role of oxidative stress in intervertebral disc degeneration: Mechanisms and therapeutic implications

Oxidative stress is one of the main driving mechanisms of intervertebral disc degeneration(IDD). Oxidative stress has been associated with inflammation in the intervertebral disc, cellular senescence, autophagy, and epigenetics of intervertebral disc cells. It and the above pathological mechanisms are closely linked through the common hub reactive oxygen species(ROS), and promote each other in the process of disc degeneration and promote the development of the disease. This reveals the important role of oxidative stress in the process of IDD, and the importance and great potential of IDD therapy targeting oxidative stress. The efficacy of traditional therapy is unstable or cannot be maintained. In recent years, due to the rise of materials science, many bioactive functional materials have been applied in the treatment of IDD, and through the combination with traditional drugs, satisfactory efficacy has been achieved. At present, the research review of antioxidant bioactive materials in the treatment of IDD is not complete. Based on the existing studies, the mechanism of oxidative stress in IDD and the common antioxidant therapy were summarized in this paper, and the strategies based on emerging bioactive materials were reviewed.

Assessing the Reproducibility of the Structured Abstracts Generated by ChatGPT and Bard Compared to Human-Written Abstracts in the Field of Spine Surgery: Comparative Analysis

BACKGROUND

Due to recent advances in artificial intelligence (AI), language model applications can generate logical text output that is difficult to distinguish from human writing. ChatGPT (OpenAI) and Bard (subsequently rebranded as "Gemini"; Google AI) were developed using distinct approaches, but little has been studied about the difference in their capability to generate the abstract. The use of AI to write scientific abstracts in the field of spine surgery is the center of much debate and controversy.

OBJECTIVE

The objective of this study is to assess the reproducibility of the structured abstracts generated by ChatGPT and Bard compared to human-written abstracts in the field of spine surgery.

METHODS

In total, 60 abstracts dealing with spine sections were randomly selected from 7 reputable journals and used as ChatGPT and Bard input statements to generate abstracts based on supplied paper titles. A total of 174 abstracts, divided into human-written abstracts, ChatGPT-generated abstracts, and Bard-generated abstracts, were evaluated for compliance with the structured format of journal guidelines and consistency of content. The likelihood of plagiarism and AI output was assessed using the iThenticate and ZeroGPT programs, respectively. A total of 8 reviewers in the spinal field evaluated 30 randomly extracted abstracts to determine whether they were produced by AI or human authors.

RESULTS

The proportion of abstracts that met journal formatting guidelines was greater among ChatGPT abstracts (34/60, 56.6%) compared with those generated by Bard (6/54, 11.1%; P<.001). However, a higher proportion of Bard abstracts (49/54, 90.7%) had word counts that met journal guidelines compared with ChatGPT abstracts (30/60, 50%; P<.001). The similarity index was significantly lower among ChatGPT-generated abstracts (20.7%) compared with Bard-generated abstracts (32.1%; P<.001). The AI-detection program predicted that 21.7% (13/60) of the human group, 63.3% (38/60) of the ChatGPT group, and 87% (47/54) of the Bard group were possibly generated by AI, with an area under the curve value of 0.863 (P<.001). The mean detection rate by human reviewers was 53.8% (SD 11.2%), achieving a sensitivity of 56.3% and a specificity of 48.4%. A total of 56.3% (63/112) of the actual human-written abstracts and 55.9% (62/128) of AI-generated abstracts were recognized as human-written and AI-generated by human reviewers, respectively.

CONCLUSIONS

Both ChatGPT and Bard can be used to help write abstracts, but most AI-generated abstracts are currently considered unethical due to high plagiarism and AI-detection rates. ChatGPT-generated abstracts appear to be superior to Bard-generated abstracts in meeting journal formatting guidelines. Because humans are unable to accurately distinguish abstracts written by humans from those produced by AI programs, it is crucial to exercise special caution and examine the ethical boundaries of using AI programs, including ChatGPT and Bard.

An Algorithmic Roadmap for the Surgical Management of Degenerative Cervical Myelopathy: A Narrative Review

Degenerative cervical myelopathy (DCM) is a leading cause of disability, and its surgical management is crucial for improving patient neurological outcomes. Given the varied presentations and severities of DCM, treatment options are diverse. Surgeons often face challenges in selecting the most appropriate surgical approach because there is no universally correct answer. This narrative review aimed to aid the decision-making process in treating DCM by presenting a structured treatment algorithm. The authors categorized surgical scenarios based on an algorithm, outlining suitable treatment methods for each case. Four primary scenarios were identified based on the number of levels requiring surgery and K-line status: (1) K-line (+) and ≤3 levels, (2) K-line (+) and ≥3 levels, (3) K-line (-) and ≤3 levels, and (4) K-line (-) and ≥3 levels. This categorization aids in determining the appropriateness of anterior or posterior approaches and the necessity for fusion, considering the surgical level and K-line status. The complexity of surgical situations and diversity of treatment methods for DCM can be effectively managed using an algorithmic approach. Furthermore, surgical techniques that minimize the stages and address challenging conditions could enhance treatment outcomes in DCM.

Meta-Analysis on Efficacy and Complications of Bone Morphogenetic Protein-2 for Posterior Fusion of Cervical Spine

OBJECTIVE

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is effective for promoting robust fusion for long-level cervical deformity and revision surgeries. However, only a few studies have reported its efficacy and complications in posterior cervical fusion (PCF).

METHODS

Therefore we evaluated the efficacy and complications of rhBMP-2 application in PCF surgery by searching 3 electronic databases (PubMed, Cochrane Database, and EMBASE) for studies that evaluated the use of rhBMP-2 in PCF. Five studies (1 prospective and 4 retrospective) were included in the meta-analysis.

RESULTS

The quality of each study was assessed, and data on pseudarthrosis, wound infection, neurologic, and immediate medical complications were extracted and analyzed. We found that the use of rhBMP-2 in PCF showed significant benefits in terms of pseudarthrosis and no significant increases in the risk for neurologic and immediate medical complications regardless of the dose. However, high-dose (>2.1 mg/level) rhBMP-2 was a risk factor for wound infection after PCF.

CONCLUSIONS

Our meta-analysis of the currently available literature suggests that patients with PCF may benefit from BMP-2 usage without increasing the risk of complications. However, dose control and containment are important to ensure a low risk of complications.

Tailor-Made Surgical Strategy for Coexistent Cervical Myelopathy and Bilateral Radiculopathy. Combined Laminoplasty, Laminectomy, and Foraminotomy: Report of Two Cases

Cervical spondylosis is a common and degenerative disease consisting of myelopathy and radiculopathy. Surgical treatment can be considered for patients with cervical spondylosis resulting in severe pain, motor weakness, ambulation difficulty, and urination disorder. As myelopathy and radiculopathy often coexist, two-staged anterior and posterior fixation/decompression surgery can be selected to resolve those two pathologies. However, due to the invasiveness of that management, posterior surgery in a single session seems favorable. In this study, we present two cases of cervical spondylosis. A 67-year-old man was complaining of pain in the neck and right upper extremity. Radiographically, cervical canal stenosis was concurrently diagnosed with the foraminal stenosis of the left C3/4 and right C6/7. Laminoplasty from C3 to C6 (left open; C3 to C5, right open; C6) and foraminotomy of the left C3/4 and right C6/7 were performed in a single session. Another 43-year-old man was bothered by pain in the neck and bilateral upper extremities resulting from cervical canal stenosis and bilateral foraminal stenosis of C6/7. Laminoplasty from C3 to C5, laminectomy of C6, and foraminotomy of bilateral C6/7 were performed in a single session. Preoperative symptoms were remitted in both cases. As described in our cases, a tailor-made combination of laminoplasty, laminectomy, and foraminotomy can effectively resolve cervical spondylosis in a single session.

Does Posterior Cord Compression From the Ligamentum Flavum Influence Clinical Outcomes After Anterior Cervical Discectomy and Fusion?

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To clarify whether outcomes of anterior cervical discectomy and fusion (ACDF) differ according to the presence of posterior cord compression from the ligamentum flavum (CCLF).

SUMMARY OF BACKGROUND DATA

Although ACDF effectively addresses anterior cord compression from disc material and bone spurs, it cannot address posterior compression. Whether ACDF could result in favorable outcomes when CCLF is present remains unclear.

PATIENTS AND METHODS

A total of 195 consecutive patients who underwent ACDF and were followed up for >2 years were included. CCLF was graded based on magnetic resonance imaging findings. Patients with CCLF grade 2 were classified as such, whereas patients with CCLF grades 0 to 1 were classified as the no-CCLF group. Patient characteristics, cervical sagittal parameters, neck pain visual analog scale, arm pain visual analog scale, and Japanese Orthopedic Association (JOA) score were assessed. Categorical variables were analyzed using a χ 2 test, whereas continuous variables were analyzed using the Student t test. Multivariable logistic regression analysis was performed to elucidate factors associated with JOA recovery rates of >50%.

RESULTS

One hundred sixty-seven patients (85.6%) were included in the no-CCLF group, whereas the remaining 28 patients (14.4%) were included in the CCLF group. Among patients in the CCLF group, 14 patients (50.0%) achieved clinical improvement. JOA score significantly improved in the no-CCLF group after the operation ( P < 0.001), whereas improvement was not appreciated in the CCLF group ( P = 0.642). JOA scores at 3 months ( P = 0.037) and 2 years ( P = 0.001) postoperatively were significantly higher in the no-CCLF group. Furthermore, the JOA recovery rate at 2 years after surgery was significantly higher in the no-CCLF group ( P = 0.042). Logistic regression demonstrated that CCLF was significantly associated with a JOA recovery rate of >50% at 2 years after surgery (odds ratio: 2.719; 95% CI: 1.12, 6.60).

CONCLUSION

ACDF performed for patients with CCLF grade 2 showed inferior JOA score improvement compared with those with CCLF grade 0 or 1. ACDF cannot remove posterior compressive structures, which limits its utility when ligamentum flavum significantly contributes to cord compression.