The influence of preoperative 12-item veterans rand physical component scores on outcomes following cervical disc replacement.

PURPOSE: To evaluate the influence of preoperative VR-12 physical component scores (PCS) on outcomes following cervical disc replacement (CDR). METHODS: Patients undergoing elective CDR were retrospectively identified. Patient-reported outcomes (PROs) of interest included VR-12 PCS/VR-12 Mental Component Score (MCS)/9-Item Patient Health Questionnaire (PHQ-9)/Short Form-12 (SF-12) PCS and MCS/Patient-Reported Outcome Measurement Information System-Physical Function (PROMIS-PF)/Visual Analog Scale-Neck Pain (VAS-NP)/VAS-Arm Pain (VAS-AP)/Neck Disability Index (NDI). Baseline up to two-year postoperative scores were obtained (average follow-up: 9.2 ± 6.8months). Two cohorts were created: VR-12 PCS < 35 or VR-12 PCS ≥ 35. Improvements in scores from baseline to six weeks postoperatively and to final follow-up were calculated. Changes in scores were compared to previously reported thresholds to determine rates of minimum clinically important difference (MCID). RESULTS: Of 127 patients, 64 were in the worse VR-12 PCS group. Patients with better VR-12 PCS were more likely to have private insurance (p = 0.034). When accounting for insurance differences, the worse VR-12 PCS group reported inferior NDI/VAS-NP/PHQ-9/PROMIS-PF/VR-12 PCS/SF-12 PCS at six weeks and final follow-up (p ≤ 0.015, all). The worse VR-12 PCS group reported greater improvements in VAS-AP and VR-12 PCS by six weeks and in NDI/VR-12 MCS/VR-12 PCS/SF-12 PCS by final follow-up (p ≤ 0.026, all). Patients with worse VR-12 PCS reported greater MCID achievement for VR-12 MCS and SF-12 PCS (p ≤ 0.034, both). CONCLUSION: Following surgery, patients with worse VR-12 PCS report greater improvements in PROs, highlighting the increased relative impact of surgery for patients with worse baseline physical function. These findings can be used to optimize patient experience perioperatively and inform postoperative expectations.

Artificial intelligence in predicting postoperative heterotopic ossification following anterior cervical disc replacement.

OBJECTIVE: This study aimed to develop and validate a machine learning (ML) model to predict high-grade heterotopic ossification (HO) following Anterior cervical disc replacement (ACDR). METHODS: Retrospective review of prospectively collected data of patients undergoing ACDR or hybrid surgery (HS) at a quaternary referral medical center was performed. Patients diagnosed as C3-7 single- or multi-level cervical disc degeneration disease with > 2 years of follow-up and complete pre- and postoperative radiological imaging were included. An ML-based algorithm was developed to predict high grade HO based on perioperative demographic, clinical, and radiographic parameters. Furthermore, model performance was evaluated according to discrimination and overall performance. RESULTS: In total, 339 ACDR segments were included (61.65% female, mean age 45.65 ± 8.03 years). Over 45.65 ± 8.03 months of follow-up, 48 (14.16%) segments developed high grade HO. The model demonstrated good discrimination and overall performance according to precision (High grade HO: 0.71 ± 0.01, none-low grade HO: 0.85 ± 0.02), recall (High grade HO: 0.68 ± 0.03, none-low grade HO: 0.87 ± 0.01), F1-score (High grade HO: 0.69 ± 0.02, none-low grade HO: 0.86 ± 0.01), and AUC (0.78 ± 0.08), with lower prosthesis­endplate depth ratio, higher height change, male, and lower postoperative-shell ROM identified as the most important predictive features. CONCLUSION: Through an ML approach, the model identified risk factors and predicted development of high grade HO following ACDR with good discrimination and overall performance. By addressing the shortcomings of traditional statistics and adopting a new logical approach, ML techniques can support discovery, clinical decision-making, and intraoperative techniques better.

Could the different surgical goals of fusion and non-fusion also be achieved in combination within the same patient? Clinical and radiological outcome of hybrid cervical spine surgery.

PURPOSE: Hybrid cervical spine surgery (HS) is a novel surgical strategy wherein an artificial disc replacement is done with a cervical fusion nearby with a stand-alone titanium cage to combine the advantages in both procedures. The aim of this study was to evaluate interactions of these devices within the same patient, and to analyze, if the different goal of each implant is accomplished. METHODS: Thirty-six patients were treated surgically within a non-randomized retrospective study framework with HS. Patients were examined preoperatively followed by clinical and radiological examination at least one year postoperative. Clinical outcome was detected with NDI, VAS arm/neck, pain self-assessment questionnaires and subjective patient satisfaction. Radiological assessments included RoM, segmental lordosis, cervical lordosis of C2-C7, subsidence, ap-migration and heterotopic ossifications (HO) at the cTDR levels. RESULTS: Statistically significant improvement of all clinical scores was observed (NDI 37.5 to 5.76; VASarm 6.41 to 0.69; VASneck 6.78 to 1.48). Adequate RoM was achieved at cTDR levels. RoM in the ACDF levels was reduced statistically significant (p < 0.001), and solid fusion (> 2°) was achieved in all evaluated fusion level. Global lordosis (C2-C7) increased statistically significant (2.4° to 8.1°). Subsidence and HO at the cTDR levels did not occur. CONCLUSIONS: HS results in preservation of the segmental motion in the cTDR and fast and solid fusion in the cage cohort simultaneously. Patient safety was proven. In carefully selected cases, HS is a safe and viable treatment option by choosing the right "philosophy" level per level.

Combined effect of artificial cervical disc replacement and facet tropism on the index-level facet joints: a finite element study.

BACKGROUND: Artificial Cervical Disc Replacement (ACDR) is an effective treatment for cervical degenerative disc diseases. However, clinical information regarding the facet joint alterations after ACDR was limited. Facet tropism is common in the sub-axial cervical spine. Our previous research indicated that facet tropism could lead to increased pressure on the cervical facet joints. This study aimed to assess the impact of facet tropism on the facet contact force and facet capsule stress after ACDR. METHODS: A C2-T1 cervical finite element model was constructed from computed tomography (CT) scans of a 28-year-old male volunteer. Symmetrical, moderate asymmetrical (7 degrees tropism), and severe asymmetrical (14 degrees tropism) models were created at the C5/C6 level by altering the facet orientation at the C5-C6 level. The C5/C6 ACDR was simulated in the intact, moderate asymmetrical and severe asymmetrical models. A 75-N follower load with 1.0-Nm moments was applied to the top of C2 vertebra in the models to simulate flexion, extension, lateral bending, and axial rotation with the T1 vertebra fixed. The range of motions (ROMs) under all moments, facet contact forces (FCFs) and facet capsule strains were tested. RESULTS: In the asymmetrical model, the right FCFs considerably increased under flexion, extension, right bending, left rotation, especially under right bending the right sided FCF of the severe asymmetrical model was about 5.44 times of the neutral position, and 3.14 times of the symmetrical model. and concentrated on the cephalad part of the facets. The facet capsule stresses on both sides remarkably increased under extension, lateral bending and right rotation. In the moderate and severe asymmetrical models, the capsule strain was greater on both sides of each position than in the symmetric model. CONCLUSIONS: The face tropism increased facet contact force and facet capsule strain after ACDR, especially under extension, lateral bending, and rotation, and also could result in abnormal stress distribution on the facet joint surface and facet joint capsule. The results suggest that face tropism might be a risk factor for post-operative facet joint degeneration progression after ACDR. Facet tropism may be noteworthy when ACDR is considered as a surgical option.

Cervical disc arthroplasty with the Baguera C prosthesis: clinical and radiological results of a 10-year follow-up study.

PURPOSE: We evaluated the long-term safety, mobility and complications of cervical total disc arthroplasty with the Baguera®C prosthesis over 10 years. METHODS: We included 91 patients treated by arthroplasty for cervical degenerative disc disease. A total of 113 prostheses were implanted (50 one-level, 44 two-level and 19 hybrid constructs). They were assessed for complications, clinically, with NDI and SF-12 questionnaires and by independent radiologists for ROM, HO, disc height and adjacent level degeneration. RESULTS: No spontaneous migration, loss of fixation, subsidence, vascular complication or dislocation were observed. The reoperation rate was 1%. About 82.7% of the patients were pain free. About 9.9% were taking occasional grade I painkillers. Motricity and sensitivity were preserved in 98.8% and 96.3%. The NDI showed an average functional disability of 17.58%, 26% lower than preoperatively. The SF-12 scores were close to normal health. The average ROM at the treated level was 7.4°. Motion was preserved in 86.6%. Lack of motion was observed in 13.4%. Grades II and III H0 were present in 53.7% and 31.7%, respectively, Grade IV was present in 13.4%. Motion was preserved in 100% of the grades 0-III. The preoperative adjacent level disc height of 4.3 mm remained stable during all the follow-ups at 4.4 mm and 4.2 mm, respectively, at 5 and 10 years. CONCLUSIONS: After 10 years, cervical arthroplasty with the Baguera®C prosthesis presents excellent safety and functional results and low complications. Motion was preserved in 86.6%, with a 7.4° ROM. Although common, HO did not hinder motion. Adjacent disc height preservation confirms some adjacent level degeneration protection.

Trends in use, outcomes, and revision procedures of anterior cervical disc replacement in the United States: a premiere database analysis from 2006-2019.

PURPOSE: We sought to characterize trends in demographics, comorbidities, and postoperative complications among patients undergoing primary and revision cervical disc replacement (pCDR/rCDR) procedures. METHODS: In this retrospective database study, the Premier Healthcare database was queried from 2006 to 2019. Annual proportions or medians were calculated for patient and hospital characteristics, comorbidities, and postoperative complications associated with CDR surgery. Trends were assessed using linear regression analyses with year of service as the sole predictor. RESULTS: A total of 16,178 pCDR and 758 rCDR cases were identified, with a median (IQR) age of 46 (39; 53) and 51 (43; 60) years among patients, respectively. The annual number of both procedures increased between 2006 and 2019, from 135 to 2220 for pCDR (p < 0.001), and from 17 to 49 for rCDR procedures (p < 0.001), with radiculopathy being the main indication for surgery in both groups. Mechanical failure was identified as a major indication for rCDR procedures with an increase over time (p = 0.002). Baseline patient comorbidity burden (p = 0.045) and complication rates (p < 0.001) showed an increase. For both procedures, an increase in outpatient surgeries and procedures performed in rural hospitals was seen (pCDR: p = 0.045; p = 0.006; rCDR: p = 0.028; p = 0.034). CONCLUSION: PCDR and rCDR procedures significantly increased from 2006 to 2019. At the same time, comorbidity burden and complication rates increased, while procedures were more often performed in an outpatient and rural setting. The identification of these trends can help guide future practice and lead to further areas of research.

The lexicon for periprosthetic bone loss versus osteolysis after cervical disc arthroplasty: a systematic review.

BACKGROUND: Periprosthetic bone loss is a common observation following arthroplasty. Recognizing and understanding the nature of bone loss is vital as it determines the subsequent performance of the device and the overall outcome. Despite its significance, the term "bone loss" is often misused to describe inflammatory osteolysis, a complication with vastly different clinical outcomes and treatment plans. Therefore, the goal of this review was to report major findings related to vertebral radiographic bone changes around cervical disc replacements, mitigate discrepancies in clinical reports by introducing uniform terminology to the field, and establish a precedence that can be used to identify the important nuances between these distinct complications. METHODS: A systematic review of the literature was conducted following PRISMA guidelines, using the keywords "cervical," "disc replacement," "osteolysis," "bone loss," "radiograph," and "complications." A total of 23 articles met the inclusion criteria with the majority being retrospective or case reports. RESULTS: Fourteen studies reported periprosthetic osteolysis in a total of 46 patients with onset ranging from 15-96 months after the index procedure. Reported causes included: metal hypersensitivity, infection, mechanical failure, and wear debris. Osteolysis was generally progressive and led to reoperation. Nine articles reported non-inflammatory bone loss in 527 patients (52.5%), typically within 3-6 months following implantation. The reported causes included: micromotion, stress shielding, and interrupted blood supply. With one exception, bone loss was reported to be non-progressive and had no effect on clinical outcome measures. CONCLUSIONS: Non-progressive, early onset bone loss is a common finding after CDA and typically does not affect the reported short-term pain scores or lead to early revision. By contrast, osteolysis was less common, presenting more than a year post-operative and often accompanied by additional complications, leading to revision surgery. A greater understanding of the clinical significance is limited by the lack of long-term studies, inconsistent terminology, and infrequent use of histology and explant analyses. Uniform reporting and adoption of consistent terminology can mitigate some of these limitations. Executing these actionable items is critical to assess device performance and the risk of revision. LEVEL OF EVIDENCE IV: Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Effect of facet joint distraction on the functional and radiological outcomes after anterior cervical disc replacement.

OBJECTIVE: The purpose of this study is to explore: 1) whether the extent of facet joint distraction affects functional outcomes following single-level anterior cervical disc replacement (ACDR) for cervical spondylotic radiculopathy and 2) whether the extent of facet joint distraction correlates with the cervical sagittal parameters. METHODS: We performed a retrospective analysis on 70 patients who had undergone a single-level ACDR to treat cervical spondylotic radiculopathy between January 2014 and December 2018. Pre- and post-operative lateral cervical spine X-ray radiographs were collected to determine radiographic parameters, including C0-C2 angle, C2-C7 angle, C7 Slope (C7S), T1 Slope (T1S), C2-C7 sagittal vertical axis (SVA), C2-C7 range of motion (ROM), Segmental ROM, disc height (DH) and inter-facet distance (ID). And the extend of facet joint distraction was evaluated by the two indexes: degree of intervertebral distraction (DID) defined and degree of facet joint distraction (DFJD). The visual analog scale (VASneck) and the Neck Disability Index scores (NDI) were adopted to demonstrate functional outcomes. Patients with the functional outcome improvement below the average were set as the positive group in the receiver operating characteristic (ROC) curve analysis, to find an optimal cut-off value of extent of facet joint distraction. RESULTS: VASneck and NDI scores improved significantly from pre- to post-operation among the entire cohort, and DFJD had a statistically significant negative correlation with ΔVASneck (p < 0.001) and ΔNDI (p < 0.001). According to ROC curve analysis, the cut-off value of DFJD for differing the appropriate and excessive distraction groups was set at 29.16% (sensitivity = 70.73%, specificity = 67.86%). Between these two groups, the ΔT1S, ΔROM, ΔVASneck, and ΔNDI were significantly different (p < 0.05). CONCLUSION: Single-segment ACDR may improve the functional outcome of patients with cervical spondylotic radiculopathy. However, those whose DFJD was greater than 29.16% had worse VASneck and NDI scores, as well as a lower ΔT1S and a lower ΔROM.

Accuracy of various fluoroscopic landmarks for determination of midline implant placement within the cervical disc space.

PURPOSE: The traditional teaching has been that proper function of a cervical disc replacement is dependent upon appropriate placement, which includes centering the device in the coronal plane. The purpose of this study was to identify the most reliable anatomical landmark for determining midline placement of an implant within the cervical disc space under fluoroscopy. METHODS: Digital fluoroscopy images were taken for each cervical level at 0 °, 2.5 °, 5 °, 7.5 °, 10 °, and 15 ° from the mid-axis by rotating the C-arm beam of six cadavers. Thin-slice CT scanning of the same levels was subsequently performed. Three independent reviewers measured the distance between anatomic structures: (a) tip of the right uncinate; (b) medial border of the right pedicle; and (c) center of the spinous processes for different x-ray angles across cervical levels C3-7. RESULTS: Both the uncinate and pedicle demonstrated superior overall accuracy to that of the spinous process (p ≤ 0.02) at all angles except at 0 ° for the pedicle where the difference was not statistically significant. Overall (pooled C3-7), the accuracy of the uncinate did not differ significantly from that of the pedicle at any fluoroscopic angle. The center of the spinous process measurement was particularly sensitive to deviations from the perfect anteroposterior fluoroscopy image. CONCLUSIONS: The results of this investigation suggest that the tip of the uncinate and the medial border of the pedicle are more accurate measures of midline in the cervical spine than the center of the spinous process and are less susceptible to inadvertent off-axis imaging.

The impact of smoking on outcomes following anterior cervical fusion-nonfusion hybrid surgery: a retrospective single-center cohort study.

BACKGROUND: There is mixed evidence for the impact of cigarette smoking on outcomes following anterior cervical surgery. It has been reported to have a negative impact on healing after multilevel anterior cervical discectomy and fusion, however, segmental mobility has been suggested to be superior in smokers who underwent one- or two-level cervical disc replacement. Hybrid surgery, including anterior cervical discectomy and fusion and cervical disc replacement, has emerged as an alternative procedure for multilevel cervical degenerative disc disease. This study aimed to examine the impact of smoking on intermediate-term outcomes following hybrid surgery. METHODS: Radiographical and clinical outcomes of 153 patients who had undergone continuous two- or three-level hybrid surgery were followed-up to a minimum of 2-years post-operatively. The early fusion effect, 1-year fusion rate, the incidence of bone loss and heterotopic ossification, as well as the clinical outcomes were compared across three smoking status groups: (1) current smokers; (2) former smokers; (3) nonsmokers. RESULTS: Clinical outcomes were comparable among the three groups. However, the current smoking group had a poorer early fusion effect and 1-year fusion rate (P < 0.001 and P < 0.035 respectively). Both gender and smoking status were considered as key factors for 1-year fusion rate. Upon multivariable analysis, male gender (OR = 6.664, 95% CI: 1.248-35.581, P = 0.026) and current smoking status (OR = 0.009, 95% CI: 0.020-0.411, P = 0.002) were significantly associated with 1-year fusion rate. A subgroup analysis demonstrated statistically significant differences in both early fusion process (P < 0.001) and the 1-year fusion rate (P = 0.006) across the three smoking status groups in female patients. Finally, non-smoking status appeared to be protective against bone loss (OR = 0.427, 95% CI: 0.192-0.947, P = 0.036), with these patients likely to have at least one grade lower bone loss than current smokers. CONCLUSIONS: Smoking is associated with poor outcomes following hybrid surgery for multilevel cervical disc disease. Current smokers had the poorest fusion rate and most bone loss, but no statistically significant differences were seen in clinical outcomes across the three groups.

Cervical sagittal alignment after Prestige LP cervical disc replacement: radiological results and clinical impacts from a single-center experience.

BACKGROUND: Cervical disc replacement (CDR) has been widely used to treat one- and two-level cervical degenerative disc disease. Studies have shown the effectiveness of CDR in preserving range of motion (ROM) and delaying adjacent segment degeneration (ASD). Cervical sagittal alignment is an important factor affecting favorable clinical outcomes in cervical spine surgery. This study aimed to explore whether cervical sagittal alignment can be maintained after CDR and to identify the impact of cervical sagittal alignment on outcomes after CDR. METHODS: This was a single-center, retrospective study. 132 patients who underwent one-level CDR were included. Cervical sagittal alignments, including cervical lordosis (CL), segmental alignment (SA), sagittal vertical axis (SVA), T1 slope (T1s), and T1s minus CL (T1s-CL), were measured. The effects of cervical sagittal alignment on the CDR outcomes were analyzed. Patients were divided into the heterotopic ossification (HO) group and ASD group to determine the potential impacts of cervical sagittal parameters. RESULTS: The cervical sagittal alignment parameters, except for the SVA, were significantly improved after CDR and showed decreasing trends at the last follow-up. Significantly higher CL and T1s were found in patients with better ROM after CDR. SVA ≥ 20 mm increased the risk of anterior HO (odds ratio = 2.945, P = 0.007). Significantly kyphotic SA and lower T1s values were found in the ASD patients than in the non-ASD patients (P < 0.05). Patients with ASD at the inferior level showed significantly worse CL (P < 0.05). CONCLUSION: CDR had limited function of improving cervical sagittal alignment. Poor cervical sagittal alignment after CDR was associated with HO, ASD, and less ROM.

Osteolysis after cervical disc arthroplasty.

PURPOSE: Cervical disc arthroplasty (CDA) has become an increasingly popular treatment for cervical degenerative disc disease. One potential complication is osteolysis. However, current literature on this topic appears limited. The purpose of this study is to elucidate the incidence, aetiology, consequence, and subsequent treatment of this complication. METHODS: A systematic literature review was performed according to the PRISMA guidelines. Studies discussing the causes, incidence and management of osteolysis after a CA were included. RESULTS: A total of nine studies were included. We divided these studies into two groups: (1) large case series in which an active radiological evaluation for osteolysis was performed (total = six studies), (2) case report studies, which discussed symptomatic cases of osteolysis (total = three). The incidence of asymptomatic osteolysis ranged from 8 to 64%; however, only one study reported an incidence of < 10% and when this case was excluded the incidence ranged from 44 to 64%. Severe asymptomatic bone loss (exposure of the implant) was found in less than 4% of patients. Bone loss from osteolysis appeared to occur early (< 1 year) after surgery and late (> 1 year) as well. Symptomatic patients with osteolysis often required revision surgery. These patients required removal of implant and conversion to fusion in the majority of the cases. CONCLUSIONS: Osteolysis after CDA is common; however, the majority of cases have only mild or asymptomatic presentations that do not require revision surgery. The timing of osteolysis varies significantly. This may be due to differences in the aetiology of osteolysis.

The safety and efficacy of hybrid surgery for multilevel cervical degenerative disc disease versus anterior cervical discectomy and fusion or cervical disc arthroplasty: a systematic review and meta-analysis.

BACKGROUND: Multilevel cervical degenerative disc disease (CDDD) can be treated surgically with anterior cervical discectomy and fusion (ACDF), cervical disc arthroplasty (CDA), or a hybrid surgery (HS) of the two in which both procedures are used at different vertebral levels. A systematic review and meta-analysis was performed to compare the clinical and radiographical outcomes of HS against ACDF or CDA alone. METHODS: Three electronic databases were searched for articles published before December 2018. The literature was searched and assessed by independent reviewers according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement. RESULTS: Eight papers were identified as eligible with a total of 424 patients. Post-operative C2-C7 range of motion (ROM) was significantly greater after HS than ACDF (p = 0.004; mean difference (MD) 6.14°). The ROM of the superior adjacent segment was significantly lower after HS than ACDF (p < 0.0001; MD - 2.87°) as was the ROM of the inferior adjacent segment (p = 0.0005; MD - 3.11°). HS patients' return to work was shorter than those who underwent ACDF (p < 0.00001; MD - 32.01 days) and CDA (p < 0.00001; MD - 32.92 days). There were no statistically significant differences in functional outcomes following CDA compared with HS. There was no significant difference in operation time, intra-operative blood loss, or post-operative complications between any of the procedures. CONCLUSION: The number of included studies was small, the heterogeneity between them was substantial, and the quality of evidence was very low. Large randomised controlled trials are required to provide strong evidence that would enable recommendation of one intervention over another.

[Impact of heterotopic ossification after single-level cervical disc replacement on adjacent segment].

Objective: To investigate the impact of heterotopic ossification (HO) after cervical disc replacement (CDR) on clinical outcome and radiological outcome of adjacent segment. Methods: The data of patients underwent single-level Prestige-LP CDR between January 2008 and March 2014 in West China Hospital with a minimum 36 months of follow-up were retrospectively analyzed in this study. The incidence of HO, whether it affected clinical outcome, and its impact on adjacent segment intervertebral disc height (IDH), range of motion (ROM) and adjacent segment degeneration were observed. The data were compared with independent sample t test between the two groups. Results: Ninety-two patients were included in this study, including 48 males and 44 females, the mean age was (44±8) years, and the mean follow-up was (62±23) months. At the final follow-up, 34 patients developed HO after CDR, but the incidence of Grade 4 HO was 7.6%. In both of the HO and non-HO groups, clinical outcomes at the final follow-up were all significantly improved when compared to those before the operation. And there was no significant differences in any clinical indexes between the HO and non-HO groups. The adjacent segment IDH before operation and at the final follow-up in the HO group and non-HO group were similar(t=0.596, 0.825 and t=0.877, 0.644, all P>0.05). The preoperative adjacent segment ROM of HO group was similar with that in non-HO group(t=0.056, 0.709, both P>0.05), but the adjacent segment ROM in HO group was higher than that in the non-HO group at the final follow-up (upper adjacent segment: 10.0°±2.0° vs 9.0°±1.3°; lower adjacent segment: 10.2°±1.9° vs 8.8°±1.3°, t=2.824, 4.022, both P<0.05). The incidence of adjacent segment degeneration of HO group was higher than that of non-HO group at the final follow-up(41.2% vs 19.0%, χ(2)=5.343, P<0.05). Conclusions: HO is a common phenomenon in the long-term follow-up after the CDR operation with Prestige LP prosthesis, but HO does not affect the improvement of clinical outcome. HO after CDR might be one of important risk factors accelerating adjacent segment degeneration.

[A long-term follow-up study on the occurrence of heterotopic ossification after artificial cervical disc replacement with Discover disc].

Objective: To analyze the incidence of heterotopic ossification after artificial cervical disc replacement with Discover disc, and to explore the effect of heterotopic ossification on postoperative radiological and clinical efficacy. Methods: From January 2010 to January 2015, 45 patients with cervical spondylosis underwent single-level artificial cervical disc replacement in Shanghai Changzheng Hospital, including 29 cases of cervical spondylotic myelopathy, 11 cases of cervical spondylotic radiculopathy and 5 cases of mixed cervical spondylosis. At the last follow-up, Mehren grading method was used for classification of heterotopic ossification, among which, grade 0-Ⅱ was defined as low grade ossification group, and 26 patients (16 male, 10 female) were enrolled in this group; grade Ⅲ-Ⅳ was defined as high grade ossification group, and 19 patients (12 males, 7 females) were included in this group. C(2-7) Cobb angle, cervical total range of motion and range of motion at index level were used to evaluate the radiological outcomes of the two groups. Japanese Orthopaedic Association (JOA) score, neck disability index (NDI) score and visual analogue scale (VAS) were used to evaluate the clinical outcomes of the two groups. The adjacent segment intervertebral disc height and range of motion were used to evaluate the effects of heterotopic ossification on adjacent segment. Results: All patients were followed up regularly for (98±18) months. There were no statistical differences between the two groups regarding to demographic data (all P>0.05). There was no significant differences in C(2-7) Cobb angle and total range of motion between the two groups at the last follow-up (all P>0.05), but range of motion at index level in the group with low grades was significantly higher than that in the group with high grades (7.8°±6.2° vs 2.6°±1.2°, t=3.60, P<0.05). There was no significant differences in JOA score, recovery rate and NDI score between the two groups (all P>0.05). There was no significant differences in the adjacent segment intervertebral disc height before operation and at the last follow-up (both P>0.05). There was no significant differences in range of motion at adjacent segment before operation (P>0.05), while range of motion at adjacent segment in the group with low grades was significantly lower than that in the group with high grades (9.5°±1.1° vs 10.6°±1.8° and 9.4°±1.4° vs 10.5°±1.7°, repectively, t=2.54, 2.31, both P<0.05). Conclusions: Heterotopic ossification does not affect the clinical outcomes, cervical curvature and cervical total range of motion after artificial cervical disc replacement with Discover disc. However, the higher grade of heterotopic ossification, the lower range of motion at index level and the higher range of motion at adjacent segment.

[Effects of preoperative segmental mobility on the clinical and radiographic outcomes following one-level artificial cervical disc replacement].

Objective: To investigate the effects of preoperative segmental range of motion (ROM) on clinical and radiographical outcomes after artificial cervical disc replacement (ACDR) and explore whether ACDR could be indicated for patients with preoperative limited or excessive segmental ROM. Methods: From January 2008 to December 2017, patients who underwent Prestige-LP ACDR in West China Hospital were retrospectively reviewed. The preoperative and postoperative X-rays of the cervical spine were collected to measure the radiographic parameters, including cervical lordosis (CL), C(2-7) ROM, disc height (DH), disc angle (DA) and ROM at the arthroplasty level. Clinical outcomes were evaluated using the Japanese Orthopedic Association (JOA) and the Neck Disability Index (NDI) scores. The correlation between preoperative segmental ROM and postoperative clinical and radiographical outcomes were also analyzed. Results: A total of 161 patients were analyzed, with 73 males and 88 females. The mean age was (44±8) years, and the follow-up period was 34 months (12-120 months). JOA and NDI scores improved after ACDR (P<0.05). However, postoperative C(2-7) ROM and ROM at the arthroplasty level were comparable with preoperative counterparts (both P>0.05). Preoperative segmental ROM positively correlated with C(2-7) ROM and ROM at the arthroplasty segment (r=0.213、0.271, both P<0.05), but was negatively correlated with the change of ROM (r=-0.534, P<0.05). The segmental ROM was 4.0°±1.0° in the limited-ROM group (A) and 14.6°±1.3° in the excessive-ROM group (B), respectively. There were significantly more patients diagnosed with cervical spondylosis in group A than in group B (35.5% vs 10.7%, P<0.05). The level-distribution was statistically different between the two groups. C(5/6) and C(6/7) were prone to limited motion in group A, while C(4/5) and C(5/6) were predisposed to excessive motion in group B (all P<0.05). After surgery, C(2-7) ROM increased for 14.2°±16.8° in group A, while paradoxically decreased for 2.2°±14.4° in group B. However, C(2-7) ROM in group B was still larger than that in group A (P<0.05). Similarly, the ROM at the arthroplasty level increased by 3.1°±3.7° in group A, whereas the values decreased by 4.4°±4.2° in group B postoperatively. In addition, group A still had less segmental ROM than group B (P<0.05). The preoperative DH in group A was less than that in group B (P<0.05). The rates of ASD, HO, and high-grade HO in group A were all higher than those in group B but without significant differences (all P>0.05). Conclusion: Preoperative segmental ROM has no significant effects on clinical outcomes after ACDR; it has a positive correlation with postoperative global and segmental ROM while is negatively correlated with ROM change.

[Long-term outcomes of Bryan artificial cervical disc replacement for degenerative cervical spondylosis].

Objective: To compare the long-term clinical effect and imaging results of Bryan artificial cervical disc replacement (ACDR) and anterior cervical discectomy and fusion (ACDF) and to explore whether ACDR can reduce the occurrence of postoperative adjacent segment degeneration (ASD) in the treatment of degenerative cervical spondylosis. Methods: It was a retrospective study. Total of 60 patients with degenerative cervical spondylosis, who had received operations by Bryan ACDR (n=27) and ACDF (n=33) in the Third Hospital of Hebei Medical University between January 2005 and December 2009 were enrolled in this study. The Japanese Orthopedic Association (JOA) scores, neck disability index (NDI), visual analogue scale (VAS), Odom's scale, cervical range of motion (ROM), surgical segment ROM, heterotopic ossification (HO) and ASD were used to evaluate the clinical and radiologic results. The indices abovementioned were compared between the two groups. Results: The VAS, NDI and JOA scores at each follow-up node in both ACDR and ACDF group were all significantly improved when compared with those before operation (all P<0.05), but there was no significant differences between the two groups (all P>0.05). Of all, 88.9%(24/27) of patients in ACDR group and 84.8%(28/33) of patients in ACDF group achieved excellent or good results, however, there was no significant difference in Odom's scale between the two groups (P>0.05). At the last follow-up, the cervical ROM in ACDR group was 43.2°±8.8°, which was slightly lower than that before operation (45.7°±10.4°), the difference was not statistically significant (t=0.954, P=0.345); the surgical segment ROM in ACDR group was 5.9°±3.6°, which was significantly reduced when compared with that before operation (8.8°±3.4°, t=3.043, P<0.01). However at the last follow-up, the cervical ROM in ACDF group was 36.4°±8.4°, which was significantly reduced when compared with that before operation (43.9°±11.1°), the difference was statistically significant (t=3.095, P<0.01). Although, there was no significant difference in the cervical ROM between the two groups before operation (t=0.643, P=0.523), and the difference was statistically significant at the last follow-up (t=3.054, P<0.01). At the last follow-up, the incidence of HO in ACDR group was 92.6%, and the high-grade HO was 37.0%. The incidence of ASD in ACDR group was 39.5%, which was much lower than that in ACDF group (61.1%, χ(2)=4.462, P=0.035). Conclusion: At minimum follow-up of 10 years, Bryan ACDR achieves a satisfactory clinical effect consistent with ACDF. In terms of advantages, ACDR could maintain the ROM of cervical and retain the ROM of the surgical segment, which reduces the occurrence of ASD by preserving motion.

An enhanced recovery after surgery pathway: association with rapid discharge and minimal complications after anterior cervical spine surgery.

OBJECTIVEEnhanced recovery after surgery (ERAS) pathways are associated with improved outcomes, lower morbidity and complications, and higher patient satisfaction in multiple surgical subspecialties. Despite these gains, there are few data to guide the application of ERAS concepts to spine surgery. The authors report the development and implementation of the first ERAS pathway for patients undergoing anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA).METHODSThis was a retrospective cohort study of prospectively collected data. The authors created a multidisciplinary pathway based on best available evidence for interventions that positively influence outcomes after anterior cervical spine surgery. Patients were followed prospectively up to postoperative day 90. Patient data were collected via electronic medical record review and included demographics, comorbidities, baseline and perioperative opioid use, postoperative complications, and length of hospital stay (LOS). ERAS process measures and compliance with pathway elements were also tracked.RESULTSThirty-three patients were cared for under the pathway (n = 25 ACDF; n = 8 CDA). The median LOS was 416 minutes (interquartile range [IQR] 210-1643 minutes). Eight patients required an extended stay-longer than 23 hours. Reasons for extended admission included pain (n = 4), dyspnea (n = 1), hypoxia (n = 1), hypertension (n = 1), and dysphagia (n = 1). The median LOS for the 8 patients who required extended monitoring prior to discharge was 1585 minutes (IQR 1423-1713 minutes). Overall pathway compliance with included process measures was 85.6%. The median number of ERAS process elements delivered to each patient was 18. There was no strong association between LOS and number of ERAS process elements provided (Pearson's r = -0.20). Twelve percent of the cohort was opioid tolerant on the day of surgery. There were no significant differences between total intraoperatively or postanesthesia care unit-administered opioid, or LOS, between opioid-tolerant and opioid-naïve patients. There were no complications requiring readmission.CONCLUSIONSAn ERAS pathway for anterior cervical spine surgery facilitates safe, prompt discharge. The ERAS pathway was associated with minimal complications, and no readmissions within 90 days of surgery. Pain and respiratory compromise were both linked with extended LOS in this cohort. Further prospective studies are needed to confirm the potential benefits of ERAS for anterior cervical spine surgery, including longer-term complications, cost, and functional outcomes.

Cervical disc arthroplasty: tips and tricks.

Cervical disc arthroplasty (CDA) is a powerful, motion-sparing treatment option for managing cervical radiculopathy or myelopathy. While CDA can be an excellent surgery for properly indicated patients, it is also less forgiving than cervical fusion. Optimally resolving patient symptoms while maintaining range of motion relies on near perfection in the surgical technique. Different CDA options exist on the market, with some having long-term proven success and others in early stages of clinical trials. We discuss the different options available for use, as well as strategies of positioning, approach, disc space preparation, implantation, and fusion prevention that we believe can help improve performance and outcomes of CDA.

Clinical and radiological outcome at 10 years of follow-up after total cervical disc replacement.

PURPOSE: Previous studies have demonstrated that total cervical disc replacement (cTDR) represents a viable treatment alternative to the 'gold standard' anterior cervical discectomy and fusion for the treatment of well-defined cervical pathologies at short- and mid-term follow-up (FU). However, the implementation and acceptance of a non-fusion philosophy is closely associated with its avoidance of adjacent segment degeneration. Proof of the functional sustainability and clinical improvement of symptoms at long-term FU is still pending. The aim of this ongoing prospective study was to investigate the clinical and radiological results of cTDR at long-term FU. METHODS: 50 patients were treated surgically within a non-randomised prospective study framework with cTDR (ProDisc C™, Synthes, Paoli, PA, USA). Patients were examined preoperatively followed by routine clinical and radiological examinations at 1, 5 and 10 years after surgery, respectively. In addition to the clinical scores, conventional X-ray images of the cervical spine were taken in anteroposterior and lateral view as well as flexion/extension images. Clinical outcome scores included parameters such as the Neck Disability Index (NDI), Visual Analogue Scale (VAS), arm and neck pain self-assessment questionnaires as well as subjective patient satisfaction rates. The radiological outcome variables included the range of motion (ROM) of the implanted prosthesis between maximum flexion and extension images, the occurrence of heterotopic ossifications and radiographic signs of adjacent segment degenerative changes. The reoperation rate following cTDR was recorded as a secondary outcome variable. RESULTS: A significant and maintained clinical improvement of all clinical outcome scores was observed after a mean FU of 10.2 years (VASarm 6.3-2.1; VASneck 6.4-1.9; NDI 21-6; p < 0.05). An increase in the incidence and the extent of heterotopic ossifications was noted during the post-operative course with a significant influence on the function of the prosthesis, which, however, did not reveal any detrimental effect on the patients' clinical symptomatology. Prosthesis mobility declined from 9.0° preoperatively and 9.1° at 1 year FU to 7.7° and 7.6° at the five- and ten-year FU examinations, respectively. Radiological signs of adjacent segment degeneration were detected in 13/38 (35.7%), however, in only 3/38 (7.9%) patients this radiological changes were associated with clinical symptoms requiring conservative treatment. Intraoperative technical failure in two cases required interbody fusion with a cage (2/50). One patient (1/48, 2.1%) treated this motion device had revision surgery at the index level. CONCLUSION: Cervical total disc replacement with ProDisc C demonstrated a significant and maintained improvement of all clinical outcome parameters at a follow-up of ≥10 years. The present long-term data reveal that with an exceptionally low implant-related reoperation rate and low symptomatic adjacent segment degeneration rate, cTDR may be regarded as a safe and viable treatment option.