More anterior bone loss in middle vertebra after contiguous two-segment cervical disc arthroplasty.

BACKGROUND: Contiguous two-segment cervical disc arthroplasty (CDA) is safe and effective, while post-operative radiographic change is poorly understood. We aimed to clarify the morphological change of the three vertebral bodies operated on. METHODS: Patients admitted between 2015 and 2020 underwent contiguous two-level Prestige LP CDA were included. The follow-up was divided into immediate post-operation (≤ 1 week), early (≤ 6 months), and last follow-up (≥ 12 months). Clinical outcomes were measured by Japanese Orthopedic Association (JOA) score, visual analogue score (VAS), and neck disability index (NDI). Radiographic parameters on lateral radiographs included sagittal area, anterior-posterior diameters (superior, inferior endplate length, and waist length), and anterior and posterior heights. Sagittal parameters included disc angle, Cobb angle, range of motion, T1 slope, and C2-C7 sagittal vertical axis. Heterotopic ossification (HO) and anterior bone loss (ABL) were recorded. RESULTS: 78 patients were included. Clinical outcomes significantly improved. Of the three operation-related vertebrae, only middle vertebra decreased significantly in sagittal area at early follow-up. The four endplates that directly meet implants experienced significant early loss in length. Sagittal parameters were kept within an acceptable range. Both segments had a higher class of HO at last follow-up. More ABL happened to middle vertebra. The incidence and degree of ABL were higher for the endplates on middle vertebra only at early follow-up. CONCLUSION: Our findings indicated that after contiguous two-segment CDA, middle vertebra had a distinguishing morphological changing pattern that could be due to ABL, which deserves careful consideration before and during surgery.

The association of cervical sagittal alignment with anterior bone loss following single-level anterior cervical surgery.

Background: Anterior bone loss (ABL) is a common phenomenon after cervical disc replacement (CDR), which can also be observed after anterior cervical discectomy and fusion (ACDF). This study aimed to investigate the incidence and severity of ABL in single-level CDR and ACDF and explore the association of cervical sagittal alignment with ABL. Methods: This is a single-center retrospective cohort study. A total of 113 patients treated with CDR and 99 patients treated with ACDF were retrospectively reviewed from January 2014 to December 2018 in West China Hospital. Radiological data were collected at pre-operation, 1 week, 3 months postoperatively, and the last follow-up. The incidence and severity of ABL after both CDR and ACDF were evaluated. Cervical sagittal alignment parameters, including C0-C2 angle, cervical lordosis (CL), C2-C7 sagittal vertical axis (cSVA), T1 slope, functional spinal unit angle, disc angle, and surgical level slope, were evaluated. Results: ABL was identified in 75 (66.4%) patients in the CDR group and 57 (57.6%) patients in the ACDF group. There were no significant differences in the incidence, severity, and location of ABL between the ACDF and CDR groups. For patients who underwent ACDF, the proportion of females was significantly higher in the ABL group (64.9% vs. 33.3%, P=0.002), whereas the body mass index (BMI) was significantly lower in the ABL group compared to the non-ABL group (22.72±3.09 vs. 24.60±3.04, P=0.002). No effect of ABL on the short-term clinical outcomes of ACDF and CDR was observed. In the ACDF group, patients with ABL had significantly smaller postoperative CL (11.83°±8.24° vs. 15.25°±8.32°, P=0.04) and cSVA (17.77±10.08 vs. 23.35±9.86 mm, P=0.007). In the CDR group, no significant differences were found in the cervical sagittal parameters between patients with and without ABL (CL: 12.58±8.70 vs. 15.46±8.50, P=0.10; cSVA: 20.95±8.54 vs. 19.40±9.43, P=0.38). Conclusions: ABL is common after both CDR and ACDF with comparable incidence and severity. Cervical sagittal alignment was closely related to ABL after ACDF yet had less influence on ABL after CDR.

Predictive Value of Cervical Degenerative Quantitative Scoring System on Postoperative Disc Height Loss After Cervical Disc Replacement.

STUDY DESIGN: A retrospective study. OBJECTIVE: In this study, a cervical degenerative quantitative scoring system was used to identify the risk factors for disc height loss after cervical disc replacement (CDR) and to verify their accuracy. BACKGROUND: Disc height loss after CDR is drawing much attention. Preoperative cervical degeneration has been proven related to postoperative disc height loss but lacked quantitative verification. PATIENTS AND METHODS: A total of 160 patients who underwent CDR with the Prestige-LP disc at our hospital between January 2011 and December 2016 were retrospectively reviewed. Disc height loss was defined as a reduction of more than 2 mm from postoperative to the final follow-up. A quantitative scoring system was used to evaluate preoperative degeneration on radiographs. Multivariate logistic regression was applied to determine predictive factors and calculate the logistic regression formula. Moreover, receiver operating characteristic curve analysis was conducted to obtain the optimal cutoff value and the area under the receiver operating characteristic curve [areas under the curve (AUC)]. RESULTS: Study subjects had a mean age of 43.51 ± 8.51 years, with a mean follow-up time of 60.14 ± 12.75 months. The overall incidence rate of disc height loss was 65.62%. Multivariate logistic regression analysis showed that endplate sclerosis ( P = 0.000) and low preoperative disc height ( P = 0.000) were independent risk factors for postoperative disc height loss. In addition, the calculated optimal cutoff point was 1 point of endplate sclerosis (AUC = 0.768) and 4.5 mm of preoperative disc height (AUC = 0.795). The regression formula established by multivariate logistic regression analysis was composed of preoperative disc height (odds ratio: 2.995, P = 0.000) and endplate sclerosis (odds ratio: 18.131, P = 0.000), with an AUC of 0.879. CONCLUSIONS: Our findings suggest that a comprehensive preoperative assessment is essential when patients with apparent endplate sclerosis and low preoperative disc height are being considered for CDR.

Effects of nurses-led multidisciplinary-based psychological management in spinal surgery: a retrospective, propensity-score-matching comparative study.

BACKGROUND: Patients in spine surgery often have emotional disorders which is caused by multi-factors. Therefore, a multidisciplinary and multimodal intervention program is required to improve emotional disorders during the perioperative period. However, related studies were rare. This study aimed to confirm that the multidisciplinary-based psychological management leading by nurses was effective in treating emotional disorders and show the assignments of the members of the multidisciplinary team with the orientations of nurses. DESIGN: A retrospective, comparative study. METHOD: This study was a retrospective cohort research and compared the results between the intervention group and control group using the Huaxi Emotional Distress Index (HEI) which was used to evaluate emotional disorders. The intervention group consisted of patients who underwent surgery between January 2018 and December 2020 after psychological management was implemented. The control group consisted of patients with regular care who underwent surgery between January 2015 and December 2017. To improve comparability between the two groups, baseline data from the recruited patients were analyzed using propensity-score-matching (PSM) based on age, sex, marital status, education, and disease region. RESULTS: A total of 539 (11.5%) people developed emotional disorders, of which 319 (6.8%), 151 (3.2%) and 69 (1.5%) had mild, moderate mood and severe emotional disorders, respectively. 2107 pairs of patients were matched after PSM. Scores of HEI in the intervention group were heightened compared with those in the control group (P<0.001) after matching. Moreover, the incidence of emotional disorders in patients decreased after implementing psychological management (P = 0.001). The severity of emotional disorders was alleviated with statistical significance as well (P = 0.010). CONCLUSIONS: Nurses-led Multidisciplinary-Based psychological management was able to reduce the incidence of emotional disorders and improve the severity of these in spine surgery patients.

[Influence of preoperative symptom duration on effectiveness of cervical disc arthroplasty in cervical spondylotic radiculopathy patients].

Objective: To investigate the influence of preoperative symptom duration on effectiveness of cervical disc arthroplasty (CDA) in cervical spondylotic radiculopathy (CSR) patients. Methods: The clinical data of 90 CSR patients who underwent single-segment CDA between January 2008 and March 2020 and met the selection criteria were retrospectively analyzed. Based on preoperative symptom duration, patients were divided into an early intervention group (preoperative symptom duration <24 months) and a late intervention group (preoperative symptom duration ≥24 months). There was no significant difference in baseline data between the two groups ( P>0.05), including age, gender, body mass index, smoking status, surgical segment, preoperative neck disability index (NDI), visual analogue scale (VAS) score, cervical lordosis (CL), C 2-C 7 range of motion (ROM), disc angle (DA), disc ROM (DROM), and disc intervertebral height (DIH). The early intervention group had a slightly higher preoperative Japan Orthopedic Association (JOA) score than the late intervention group ( P<0.05). Perioperative indicators such as operation time, intraoperative blood loss, and postoperative hospital stay were recorded. The changes of JOA score, NDI, and VAS score at last follow-up compared with those before operation were used to evaluate the clinical efficacy, and the imaging evaluation of CL, C 2-C 7 ROM, DA, DROM, and DIH was performed before operation, immediately after operation, and at last follow-up. The incidence of prosthesis-related complications, including heterotopic ossification (HO), anterior bone loss (ABL), and prosthesis subsidence, was also assessed at last follow-up. Results: Patients in both groups were followed up 24-120 months, with an average of 53.4 months. There was no significant difference in operation time, intraoperative blood loss, or follow-up duration between the groups ( P>0.05). However, the late intervention group had significantly longer postoperative hospital stay compared to the early intervention group ( P<0.05). At last follow-up, there was no significant difference in the changes of JOA score, NDI, and VAS score between the two groups before and after operation ( P>0.05). During the follow-up, there was no surgical revision in the two groups, and there was no significant difference in the incidence of HO, ABL, and prosthesis subsidence between the two groups at last follow-up ( P>0.05). Imaging evaluation showed that there was no significant difference in CL, C 2-C 7 ROM, DA, DROM, and DIH between the two groups at each time point before and after operation ( P>0.05). The intra-group comparison showed that the early intervention group could maintain the immediate postoperative CL at last follow-up, while the late intervention group had recovered to the preoperative level. Additionally, the C 2-C 7 ROM, DROM, and DA had all recovered to preoperative levels at last follow-up in both groups; meanwhile, the DIH significantly increased immediately after operation and sustained until the last follow-up. Conclusion: Preoperative symptom duration significantly affects the effectiveness of CDA in CSR patients. Patients with preoperative symptom duration ≥24 months have longer postoperative hospital stays and potentially poorer ability to maintain CL compared with patients with preoperative symptom duration <24 months.

Early Outcomes of Bone Autografting in the Bilateral Atlantoaxial Joints Applied in Posterior Fusion Surgery.

OBJECTIVE: Cable-dragged reduction and cantilever beam internal fixation can provide promising results in the treatment of atlantoaxial dislocation or instability. However, bilateral atlantoaxial joints bone autografting has not been conducted in this technique. We aim to evaluate the safety and effectiveness of bilateral atlantoaxial joints bone autografting in posterior cable-dragged reduction and cantilever-beam internal fixation. METHODS: In this retrospective study, we included 14 patients with a minimum 24-month follow-up from December 2019 to September 2020. The granular bone harvested from the iliac crest was packed into the bilateral atlantoaxial joints of 14 patients in posterior cable-dragged reduction and cantilever-beam internal fixation. X-ray imaging and cervical computed tomography (CT) were performed during follow-up. The time required for bone fusion was recorded. The clinical outcomes were evaluated using the JOA scores, NDI, and VAS scores. Mann-Whitney U test, the chi-squared test, or the Fisher exact test were used to compare the two groups regarding patient characteristics, clinical outcomes, bone fusion rates, and cervical sagittal alignment. RESULTS: The operations were successfully performed in all patients without any intraoperative complications. The mean operation time was (169.64 ± 20.91) minutes, and the intraoperative blood loss was (130.71 ± 33.62) mL. All patients received satisfactory reductions and firm bony fusion at the final follow-up. The fusion rates were 64.29% in the atlantoaxial joints and 21.43% in post bone graft area at 3 months postoperatively, and a significant difference was observed (p = 0.022). Besides, the cervical sagittal alignment in all patients was well maintained in the last follow-up compared to preoperatively. Importantly, a complete bony fusion in the atlantoaxial joints was observed in all patients. Moreover, the JOA, NDI, and VAS scores had improved significantly at the last follow-up. CONCLUSION: Bone autografting of the bilateral atlantoaxial joints is a safe and effective technique to increase bone fusion rates, shorten bone fusion time, and reduce complication rates when the cable-dragged reduction and cantilever beam internal fixation approach is used. Therefore, it is a cost-effective surgical procedure for treating patients with atlantoaxial dislocation or instability.

Anterior cervical X-shape-corpectomy and fusion vs. anterior cervical corpectomy and fusion for two-level cervical spondylosis.

PURPOSE: Anterior cervical X-shape-corpectomy and fusion (ACXF) is a novel cervical surgery, designed as partial alternative to the classic technique, anterior cervical corpectomy and fusion (ACCF). The aim of this study was to evaluate the early-stage outcomes of ACXF in treating two-level cervical spondylosis (CS) through comparisons with ACCF. METHODS: A retrospectively comparative study was conducted in two cohorts of patients who underwent single-vertebral ACXF or ACCF to treat two-level CS during September 2019 and October 2021. Clinical and radiological data of all the patients were collected from pre-operation to 1 year after the surgery, following by intra- and intergroup analyses and comparisons. RESULTS: Fifty-seven patients were included, with 24 undergoing ACXF and 33 undergoing ACCF. ACXF group had significantly shorter drainage duration (2.13 ± 0.61 days vs. 3.48 ± 1.30 days, P < 0.001) and less drainage volume (30.21 ± 26.88 ml vs. 69.30 ± 37.65 ml, P < 0.001) than ACCF group. Both techniques significantly improved all the clinical parameters (P < 0.01) with comparable effects (P > 0.05). Each complication rate in ACXF group was lower than that in ACCF group without significant difference (P > 0.05). ACXF showed a significantly smaller transverse decompression range than ACCF (11.93 ± 1.27 mm vs. 16.29 ± 1.88 mm, P < 0.001). Postoperatively, ACXF yielded a comparable fusion rate (P > 0.05) and a significantly lower subsidence rate (P < 0.01) than ACCF technique at all time points. CONCLUSIONS: ACXF is a potential surgical alternative for certain patients with two-level CS, as it provides both adequate decompression range and fewer adverse events than ACCF. The further modifications on ACXF worth exploration.

Distal clavicle fractures treated by anteroinferior plating with a single screw: Two case reports.

BACKGROUND: For the treatment of distal clavicle fractures, each treatment method has its own advantages and disadvantages, and there is no optimal surgical solution. CASE SUMMARY: Based on this, we report 2 cases of distal clavicle fractures treated utilizing an anterior inferior plate with a single screw placed in the distal, in anticipation of providing a better surgical approach to distal clavicle fracture treatment. Two patients were admitted to the hospital after trauma with a diagnosis of distal clavicle fracture, and were admitted to the hospital for internal fixation of clavicle fracture by incision and reduction, with good postoperative functional recovery. CONCLUSION: With solid postoperative fixation and satisfactory prognostic functional recovery, this technique has been shown to be simple, easy to perform and effective.

Overloaded vertebral body: a unique radiographic phenomenon following multilevel anterior cervical discectomy and fusion.

PURPOSE: Because previous studies have not focused on postoperative cervical collapse, the purpose of the present study was to introduce the overloaded vertebral body (OVB) phenomenon following multilevel zero-profile anterior cervical discectomy and fusion (ACDF) as well as to investigate its effects on radiographic outcomes. METHODS: We conducted a retrospective study involving patients who underwent ACDF. A total of 55 patients were included in the analysis, including 110 OVB and 110 non-OVB. The evaluated vertebral parameters included the vertebral cross-sectional area (CSA), wedge angle (WA), vertebral height [anterior (AH) and posterior (PH)] and anterior-posterior vertebral diameter [upper (UD) and lower (LD)]. RESULTS: The CSA and WA were significantly lower in the OVB group than in the non-OVB group at 3, 6, and 12 months after surgery as well as at the final follow-up (p < 0.01). The AH of the OVB group was significantly lower at 3, 6, and 12 months after surgery as well as at the final follow-up compared to 1 week after surgery (p < 0.01). CONCLUSIONS: OVB, a new phenomenon following multilevel ACDF, is defined as the cervical vertebral body located in the middle of the surgical segments in multilevel anterior cervical spine surgery. Statistical analysis of vertebral parameters, including CSA, WA, AH, PH, UD, and LD, showed that OVB occurs mainly at the anterior edge of the vertebra and that its largest radiographic manifestation is the loss of height at the anterior edge of the vertebra in the early postoperative period.

A Novel Intraoperative Posture-Adjustment Apparatus for Correction of Cervical Lordosis in Anterior Cervical Surgery.

OBJECTIVE: Cervical alignment is a crucial factor related to the success of anterior cervical surgical procedures. In patients with severe spinal cord compression, a traditional neck pillow (TNP) may not adequately correct cervical position during surgery. Therefore, the aim of this study was to introduce this innovative intraoperative posture-adjustment apparatus (IPAA), and explored its clinical and radiological results in cervical angle correction against TNP in patients who had undergone anterior cervical surgery. METHODS: The clinical and radiological data of 86 patients who underwent anterior cervical surgery with a minimum follow-up period of 1 year were retrospectively reviewed. Of these, 58 patients underwent IPAA, whereas 28 underwent TNP. Radiological parameters such as the degree of C2-C7 lordosis (CL), functional spinal unit angle (FSUA), C7 slope (C7S), fusion rate, and adjacent segment disease (ASD) were recorded and compared between the groups. Clinical outcomes including the Japanese Orthopaedic Association (JOA), neck disability index (NDI), visual analogue scale (VAS) for neck and arm were recorded. Complications such as kyphosis, dysphagia, Braden Scale score, revision surgery, hematoma, cerebrospinal fluid leakage, wound infection, and deep venous thrombosis were also recorded. The independent t-test or Mann-Whitney U test was used to compare continuous data, and categorical variables were assessed using the Pearson's chi-square test or Fisher's exact test. RESULTS: Compared with the pre-operative data, the post-operative CL, FSUA, and C7S were significantly increased in both groups. CL, FSUA, and C7S in the IPAA group (14.44 ± 4.94°, 7.36 ± 2.91°, 16.54 ± 4.63°) were significantly higher than those in the TNP group (7.17 ± 8.19°, 4.99 ± 5.36°, 14.19 ± 4.48°; P < 0.05). Although there were no significant differences between the groups in terms of VAS arm and JOA scores, the post-operative and final follow-up NDI and VAS neck scores in the IPAA group were significantly lower than those in the TNP group (p < 0.05). At the last follow-up, the TNP group had significantly more kyphotic patients than the IPAA group (2 vs. 0, p = 0,041). There was no significant difference between the groups in terms of fusion rate, ASD, or complications such as dysphagia, Braden's Scale score, revision surgery, hematoma, cerebrospinal fluid leakage, wound infection, or deep venous thrombosis. CONCLUSION: IPAA was shown to be more effective than TNP in adjusting cervical alignment (CL, FSUA, and C7S). These findings suggest that IPAA could be used as an alternative way to TNP in neck setting and cervical alignment adjustment and IPAA could potentially improve clinical outcomes after anterior cervical surgery.

Cervical Disc Arthroplasty for the Treatment of Noncontiguous Cervical Degenerative Disc Disease: Results of Mid- to Long-Term Follow-up.

OBJECTIVE: The long-term results of cervical disc arthroplasty (CDA) for noncontiguous cervical degenerative disc disease (CDDD) are still uncertain. Moreover, it is unclear whether CDA delays or avoids the degeneration of the intermediate segment (IS), leading to controversy in the field. Therefore, this study aimed to investigate the mid- to long-term clinical and radiographic outcomes of CDA in treating noncontiguous CDDD and to explore whether the IS degenerated faster after CDA than other non-surgically treated adjacent segments. METHODS: We retrospectively analyzed patients with noncontiguous CDDD who underwent CDA in our department between January 2008 and July 2018. The patients were divided into the CDA and hybrid surgery (HS) groups, and clinical and radiographic outcomes were evaluated at routine postoperative intervals. Clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA), neck disability index (NDI), and visual analogue scale (VAS), while radiographic outcomes included cervical lordosis (CL), C2-C7 range of motion (ROM), segmental ROM, and disc angle (DA) at the arthroplasty level. Complications were also evaluated.Pre- and postoperative values were compared using paired t-tests or Wilcoxon rank-sum tests. Independent Student t-tests or Mann-Whitney U tests analyzed continuous data between CDA and HS groups, while chi-square or Fisher exact tests assessed categorical data. RESULTS: Sixty-four patients with noncontiguous CDDD, with 31 in the CDA group and 33 in the HS group, were evaluated. The mean follow-up time was over 70 months. The most frequently involved levels were C4/5 and C5/6. Both groups showed significant improvements in JOA, NDI, and VAS values after surgery. Although CL was maintained, the CL in the CDA group was consistently lower than that in the HS group (p < 0.05). There was a significant decrease in C2-C7 ROM (p < 0.05), but at the last follow-up, the C2-C7 ROM in the CDA group was greater than that in the HS group (p < 0.05). At the last follow-up, 44.3% of arthroplasty levels had developed heterotopic ossification (HO), and 48.45% had developed anterior bone loss (ABL). In addition, adjacent segment degeneration (ASDeg) was observed in the IS (22.7%), superior adjacent segment (20.6%)and inferior adjacent segment (21.9%). CONCLUSION: CDA or CDA combined with fusion are viable treatments for noncontiguous CDDD, with satisfactory outcomes after mid-to-long-term follow-up. ASDeg is similar in non-surgical segments after 70 months of follow-up. ROM of the IS issimilar to preoperative levels, indicating CDA does not increase the risk of IS degeneration.

Risk Factors of Nonfusion after Anterior Cervical Decompression and Fusion in the Early Postoperative Period: A Retrospective Study.

OBJECTIVE: Although high fusion rates have been reported for anterior cervical decompression and fusion (ACDF) in the medium and long term, the risk of nonfusion in the early period after ACDF remains substantial. This study investigates early risk factors for cage nonfusion in patients undergoing single- or multi-level ACDF. METHODS: This was a retrospective study. From August 2020 to December 2021, 107 patients with ACDF, including 197 segments, were enrolled, with a follow-up of 3 months. Among the 197 segments, 155 were diagnosed with nonfusion (Nonfusion group), and 42 were diagnosed with fusion (Fusion group) in the early period after ACDF. We assessed the significance of the patient-specific factors, radiographic indicators, serum factors, and clinical outcomes. The Wilcoxon rank sum test, t-tests, analysis of variance, and stepwise multivariate logistic regression were used for statistical analysis. RESULTS: Univariate analysis showed that smoking, insufficient improvement in the C2-7 Cobb angle (p = 0.024) and the functional spinal unit Cobb angle (p = 0.022) between preoperative and postoperative stages and lower serum calcium (fusion: 2.34 ± 0.12 mmol/L; nonfusion: 2.28 ± 0.17 mmol/L, p = 0.003) ß-carboxyterminal telopeptide end of type 1 collagen (ß-CTX) (fusion: 0.51 [0.38, 0.71]; nonfusion: 0.43 [0.31, 0.57], p = 0.008), and N-terminal fragment of osteocalcin (N-MID-BGP) (fusion: 18.30 [12.15, 22.60]; nonfusion: 14.45 [11.65, 18.60], p = 0.023) are risk factors for nonfusion in the early period after ACDF. Stepwise logistic regression analysis revealed that poor C2-7 Cobb angle improvement (odds ratio [OR], 1.107 [1.019-1.204], p = 0.017) and lower serum calcium (OR, 3.700 [1.138-12.032], p = 0.030) are risk factors. CONCLUSIONS: Patients with successful fusion after ACDF had higher preoperative serum calcium and improved C2-7 Cobb angle than nonfusion patients at 3 months. These findings suggest that serum calcium could be used to identify patients at risk of nonfusion following ACDF and that correcting the C2-7 Cobb angle during surgery could potentially increase fusion in the early period after ACDF.

Mechanical properties of an elastically deformable cervical spine implant.

Anterior cervical surgery is widely accepted and time-tested surgical procedure for treating cervical radiculopathy and myelopathy. However, there is concern about the high adjacent segment degeneration rate and implant subsidence after the surgery using the traditional polyetheretherketone cage. Thus, we creatively designed a polyurethane cervical implant that can continuous load-sharing through elastic deformation and decrease postoperative stress concentration at adjacent segments. In this study, the design rationality and safety of this novel implant was evaluated based on several mechanical parameters including compression test, creeping test, push-out test and subsidence test. The results showed that the novel cervical implant remained intact under the compressive axial load of 8000 N and continues to maintained the elastic deformation phase. The minimum push-out load of the implant was 181.17 N, which was significantly higher than the maximum compressive shear load of 20 N experienced by a normal human cervical intervertebral disc. Besides, the creep recovery behaviour of the implant closely resembled what has been reported for natural intervertebral discs and clinically applied cervical devices in literature. Under the load of simulating daily activities of the cervical spine, the implant longitudinal displacement was only 0.54 mm. In conclusion, this study showed that the current design of the elastically deformable implant was reasonable and stable to fulfil the mechanical requirements of a cervical prosthesis under physiological loads. After a more comprehensive understanding of bone formation and stress distribution after implantation, this cervical implant is promising to be applied to certain patients in clinical practice.

Is Cervical Disc Arthroplasty an Effective Treatment for Cervical Degenerative Disease With Osteopenia?

STUDY DESIGN: Retrospective case-control study. OBJECTIVES: To evaluate postoperative outcomes of single-level cervical disc arthroplasty (CDA) in patients with osteopenia and compare these results with a matched cohort of normal bone mineral density (BMD). METHODS: Patients who had undergone single-level CDA were collected and screened. Included patients were divided into the osteopenia group and the normal group. 38 eligible patients with osteopenia were included in the final analysis. Subsequently, a 1:1 match was utilized. Clinical, radiographic data, and complications were recorded. Appropriate statistical methods were applied to conduct analysis using SPSS version 24.0. RESULTS: The mean follow-up time was 30.5 ± 27.3 months. The osteopenia group achieved satisfactory clinical outcomes, with no significant intergroup differences. Additionally, there were no significant differences between groups in any of the radiological parameters, either in cervical alignment or segmental height, or range of motion. The radiological incidence rate of adjacent segmental degeneration and heterotopic ossification (HO) was comparable in both groups, respectively, with a similar composition of ROM-limiting HO. However, the osteopenia group had a tendency of more implant subsidence (2.7% vs 15.2%). The logistic regression analysis showed the osteopenia group had a significantly higher incidence rate of anterior bone loss (ABL) (OR = 5.37, 95% CI: 1.50 - 19.22). CONCLUSIONS: Single-level CDA for patients with osteopenia achieved similar satisfactory clinical outcomes compared with the normal BMD group. Meanwhile, the osteopenia group maintained adequate sagittal balance and segmental height. Based on this observation, this option may be feasible for selected patients with osteopenia.

Self-healing hydrogels for bone defect repair.

Severe bone defects can be caused by various factors, such as tumor resection, severe trauma, and infection. However, bone regeneration capacity is limited up to a critical-size defect, and further intervention is required. Currently, the most common clinical method to repair bone defects is bone grafting, where autografts are the "gold standard." However, the disadvantages of autografts, including inflammation, secondary trauma and chronic disease, limit their application. Bone tissue engineering (BTE) is an attractive strategy for repairing bone defects and has been widely researched. In particular, hydrogels with a three-dimensional network can be used as scaffolds for BTE owing to their hydrophilicity, biocompatibility, and large porosity. Self-healing hydrogels respond rapidly, autonomously, and repeatedly to induced damage and can maintain their original properties (i.e., mechanical properties, fluidity, and biocompatibility) following self-healing. This review focuses on self-healing hydrogels and their applications in bone defect repair. Moreover, we discussed the recent progress in this research field. Despite the significant existing research achievements, there are still challenges that need to be addressed to promote clinical research of self-healing hydrogels in bone defect repair and increase the market penetration.

Cervical collar use following anterior cervical hybrid surgery: protocol for a prospective randomized, time-controlled trial.

INTRODUCTION: Cervical hybrid surgery (HS) combines anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) to establish an individualized surgical plan for patients with multiple cervical disc degenerative diseases. In order to maintain the stability of the spine after HS, an external cervical collar is often used. However, there is still controversy regarding the importance of a cervical collar following surgery. This study aims to determine whether the cervical collar is effective and how long it should be worn after surgery. METHODS: This is a randomized, single-center, prospective, parallel-controlled trial. Eligible participants will be selected according to the inclusion and exclusion criteria. The primary outcome is the neck disability index, which will be evaluated before surgery and at one week, 3 weeks, 6 weeks, 3 months, 6 months, and 12 months following surgery. The secondary outcomes consist of the Japanese Orthopedic Association Scores, MOS 36-item short-form health survey (SF-36), visual analog scale, Pittsburgh Sleep Quality Index (PSQI), Bazaz dysphagia scoring system, Falls Efficacy Scale, cervical collar satisfaction score, neck soft tissue assessment, and Braden Scale, as well as radiologic assessments for cervical lordosis, disc height of the operative levels, fusion rate, range of motion (ROM), and complications including anterior bone loss, prosthesis migration, and heterotopic ossification. The clinical and radiologic examinations were performed by investigators with no therapeutic relationship with the individual patient. All radiographs were examined by one independent radiologist. ETHICS AND DISSEMINATION: The results of this study will be published in peer-reviewed journals and presented at conferences. Upon completion of this trial, our findings could provide an appropriate cervical collar-wearing guideline for patients receiving HS. TRIAL REGISTRATION: ChiCTR.org.cn ChiCTR2000033002. Registered on 2020-05-17.

Cervical sagittal balance after consecutive three-level hybrid surgery versus anterior cervical discectomy and fusion: radiological results from a single-center experience.

INTRODUCTION: According to the different numbers and relative locations of cervical disc replacement (CDR) and anterior cervical discectomy and fusion (ACDF), three-level hybrid surgery (HS) has many constructs. The purpose of this retrospective study was to compare the sagittal alignment parameters of HS and ACDF for cervical degenerative disc disease (CDDD) and the association of the respective parameters. METHODS: This study involved patients with three-level CDDD who underwent ACDF or HS at our institution between June 2012 and August 2021. This follow-up included one-level CDR and two-level ACDF (type I group), two-level CDR and one-level ACDF (type II group) and three-level ACDF. Cervical sagittal alignment parameters included cervical lordosis (CL), segment alignment (SA), T1 slope (T1S), C2-C7 sagittal vertical axis (SVA), T1S-CL, C2 slope (C2S), occipital to C2 angle (O-C2A) and segment range of motion (ROM). Postoperative complications included adjacent segment degeneration, imbalance, prosthetic subsidence and heterotopic ossification. RESULTS: The three groups with a total of 106 patients were better matched in terms of demographics. Patients who underwent HS had significantly higher CL than those who underwent ACDF at 1 week, 6 months, 12 months and the final follow-up after surgery, as well as significantly better SA at 12 months and the final follow-up. There was no significant difference in T1S, SVA, T1S-CL, C2S, O-C2A or segment ROM among the three groups after surgery. The T1S-CL was significantly associated with C2S in the type I and type II groups at the preoperative and final follow-up. There was no significant difference in postoperative complications among the three groups. CONCLUSIONS: Most improvements in cervical sagittal alignment (CL, SA, T1S, SVA, T1S-CL, C2S, O-C2A, and segmental ROM) were observed in all three groups postoperatively. HS was more advantageous than ACDF in the maintenance of postoperative CL and SA. Thus, three-level HS may be better for maintaining cervical curvature. The number of replacement segments differed in those who underwent HS but did not affect the correlation between T1S-CL and C2S, both of which are well balanced.

Uncovertebral Joint Fusion Versus End Plate Space Fusion in Anterior Cervical Spine Surgery: A Prospective Randomized Controlled Trial.

BACKGROUND: The uncovertebral joint is a potential region for anterior cervical fusion. Currently, we are aware of no clinical trials on human uncovertebral joint fusion (UJF). The purpose of this study was to compare the time it took to achieve osseous union/fusion and the clinical efficacy of UJF to end plate space fusion (ESF)-i.e., traditional anterior cervical discectomy and fusion (ACDF)-in anterior cervical surgery. METHODS: Patients with single-level cervical spondylosis were recruited from April 2021 through October 2022 and randomly divided into the UJF and ESF groups, with 40 patients in each group. Autologous iliac bone was used for bone grafting in both groups. The primary outcome was the early fusion rate at 3 months postoperatively. Secondary outcomes included the prevalence of complications and patient-reported outcome measures (PROMs), including the Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI), and visual analog scale (VAS) scores for arm and neck pain. RESULTS: A total of 74 patients (92.5%) with an average age of 49.8 years (range, 26 to 65 years) completed the trial and were included in the analysis. There was no significant difference between the 2 groups at baseline. The operative duration and intraoperative blood loss were also comparable between the 2 groups. The fusion rate in the UJF group was significantly higher than that in the ESF group at 3 months (66.7% compared with 13.2%, p < 0.0001) and 6 months (94.1% compared with 66.7%, p = 0.006) after the operation. No significant difference was found in the fusion rate between the 2 groups 12 months postoperatively. Overall, the PROMs significantly improved after surgery in both groups and did not differ significantly between the groups at any follow-up time point. The prevalence of complications was not significantly different between the 2 groups. CONCLUSIONS: In our study of anterior cervical fusion surgery, we found that the early fusion rate after UJF was significantly higher than that after ESF. LEVEL OF EVIDENCE: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Research trends and hotspots of mesenchymal stromal cells in intervertebral disc degeneration: a scientometric analysis.

Mesenchymal stromal cells (MSCs) are important potential candidates for regenerative therapy for intervertebral disc degeneration (IDD). This scientometric study aimed to summarize the main research trends, identify current research hotspots, and measure the networks of the contributors and their scientific productivity. A total of 1102 publications regarding MSC in IDD were recognized from January 2000 to April 2022. The number of records every year followed an overall uptrend with fluctuations. The main trend of research demonstrated the practice of gradually applying MSC-based therapy to IDD with the assistance of advances in biomaterials and IDD pathology. A recent focus on MSC-derived exosomes and notochordal cells was detected. The basic studies in this field were mainly contributed to by Japan, the USA, and European countries, while China dominated in the number of recent publications. Tokai University with Daisuke Sakai was the most productive contributor. Cell biology, tissue engineering, and biomaterials were the categories with deep engagement in research of this field.

Biomechanical performance of the novel assembled uncovertebral joint fusion cage in single-level anterior cervical discectomy and fusion: A finite element analysis.

Introduction: Anterior cervical discectomy and fusion (ACDF) is widely accepted as the gold standard surgical procedure for treating cervical radiculopathy and myelopathy. However, there is concern about the low fusion rate in the early period after ACDF surgery using the Zero-P fusion cage. We creatively designed an assembled uncoupled joint fusion device to improve the fusion rate and solve the implantation difficulties. This study aimed to assess the biomechanical performance of the assembled uncovertebral joint fusion cage in single-level ACDF and compare it with the Zero-P device. Methods: A three-dimensional finite element (FE) of a healthy cervical spine (C2-C7) was constructed and validated. In the one-level surgery model, either an assembled uncovertebral joint fusion cage or a zero-profile device was implanted at the C5-C6 segment of the model. A pure moment of 1.0 Nm combined with a follower load of 75 N was imposed at C2 to determine flexion, extension, lateral bending, and axial rotation. The segmental range of motion (ROM), facet contact force (FCF), maximum intradiscal pressure (IDP), and screw-bone stress were determined and compared with those of the zero-profile device. Results: The results showed that the ROMs of the fused levels in both models were nearly zero, while the motions of the unfused segments were unevenly increased. The FCF at adjacent segments in the assembled uncovertebral joint fusion cage group was less than that that of the Zero-P group. The IDP at the adjacent segments and screw-bone stress were slightly higher in the assembled uncovertebral joint fusion cage group than in those of the Zero-P group. Stress on the cage was mainly concentrated on both sides of the wings, reaching 13.4-20.4 Mpa in the assembled uncovertebral joint fusion cage group. Conclusion: The assembled uncovertebral joint fusion cage provided strong immobilization, similar to the Zero-P device. When compared with the Zero-P group, the assembled uncovertebral joint fusion cage achieved similar resultant values regarding FCF, IDP, and screw-bone stress. Moreover, the assembled uncovertebral joint fusion cage effectively achieved early bone formation and fusion, probably due to proper stress distributions in the wings of both sides.