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

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 two 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<0.001) and ROM (p<0.001) was observed in the LPF and ACDF groups, respectively. LPF was associated with a significant decrease in C2-C7 lordosis (p<0.001), while ACDF caused a significant decrease in cervical ROM (p<0.001). ACDF effectively improved neck pain VAS (p<0.001) and NDI (p<0.001), while neck pain did not significantly improve after LPF (p=0.103). Furthermore, neck pain VAS (p=0.026) and NDI (p=0.021) 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=0.502; NDI, p=0.085). Arm pain VAS and JOA score both significantly improved after LPF (p=0.003 and 0.043, respectively) or ACDF (p<0.001 and 0.039, respectively), and postoperative results were not significantly different between the two 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.

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.

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.

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.