Anterior Cervical Discectomy and Fusion Alters Whole-Spine Sagittal Alignment

The Effect of Cervical Fusion on Functional Sagittal Spinal Alignment Based on the Inflection Point: Case Series Study

STUDY DESIGN

A retrospective radiologic study.

OBJECTIVE

The inflection point is the disc space between a lordotic and kyphotic segment of spine. To our knowledge, there has been no study evaluating changes in functional sagittal alignment determined by inflection points after cervical fusion surgery. The purpose is to identify changes in functional sagittal alignment after cervical fusion as determined by functional segments between cervicothoracic and thoracolumbar inflection points.

METHODS

Standing radiographs of the sagittal whole spine were taken in 62 patients who underwent cervical fusion procedures. We identified cervicothoracic and thoracolumbar inflection points in the sagittal plane and measured Cobb angles of resulting "functional" cervical, thoracic, and lumbar segments. We also measured the C2 and T1 sagittal vertical axis (SVA) distance to S1 and the anatomic cervical lordosis, thoracic kyphosis, lumbar lordosis, spinopelvic parameters, and T1 sagittal slope. We compared the pre- and post-op values.

RESULTS

The functional cervical segment and T1 sagittal slope increased postoperatively. C2 and T1 SVA distance to S1 decreased postoperatively. In patients with a single level fusion or lower instrumented vertebra (LIV) proximal or equal to C6, functional cervical segment, and anatomic cervical lordosis increased postoperatively. In those with multiple level fusion or LIV distal or equal to C7, the C2 SVA distance to S1 decreased postoperatively.

CONCLUSIONS

After cervical fusion surgery, functional cervical sagittal parameters determined by the inflection point improve without changes in the anatomic sagittal parameters. Postoperative changes in functional sagittal parameters were affected by the number of fused levels and LIV.

Impact of preoperative cervical sagittal alignment for cervical myelopathy caused by ossification of the posterior longitudinal ligament on surgical treatment

BACKGROUND

Surgical procedures for cervical myelopathy caused by ossification of the posterior longitudinal ligament (OPLL) are often chosen based on OPLL size and cervical spine alignment. Recently, cervical sagittal alignment based on sagittal vertical axis (SVA) has received increased attention as an important determinant of radiological and clinical outcomes after surgery. This study aimed to investigate the impact of SVA-based cervical sagittal alignment on surgical treatment for cervical OPLL by reviewing a previous retrospective cohort in which its concept was not taken into account in the surgical procedure choices.

METHODS

We reviewed a total of 96 consecutive patients who underwent surgery for cervical myelopathy caused by OPLL from 2008 to 2014. We performed anterior decompression with fusion (ADF) or posterior decompression with fusion (PDF) on patients with massive OPLL or kyphotic alignment, and we performed laminoplasty (LAMP) on patients without massive OPLL or kyphotic alignment. CSVA (center of gravity of the head - C7 SVA), CL (C2-7 lordotic angle) and C7 slope were measured in cervical X-ray at standing position. Clinical results were evaluated using C-JOA score. We divided patients into two subgroups based on the preoperative CSVA: the Low-CSVA (CSVA <40 mm) and High-CSVA (CSVA ≥40 mm) subgroups.

RESULTS

In the Low-CSVA subgroup, none of the three operations had an effect on the CL. In contrast, in the High-CSVA subgroup, while ADF and PDF had no effect on the CL, LAMP worsened the CL postoperatively. The recovery rates of the C-JOA scores in the Low-CSVA subgroup showed no significant differences among the three operations; however in the High-CSVA subgroup, LAMP resulted in worse recovery rate of the C-JOA score than ADF or PDF.

CONCLUSIONS

LAMP is not suitable for patients with cervical myelopathy caused by OPLL who have high CSVA alignment, even in cases without massive OPLL or kyphotic alignment.

Risk Factors of Unplanned Readmission after Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis

PURPOSE

With an increasing number of anterior cervical discectomy and fusion (ACDF) being conducted for degenerative cervical disc disease, there is a rising interest in the related quality of management and healthcare costs. Unplanned readmission after ACDF affects both the quality of management and medical expenses. This meta-analysis was performed to evaluate the risk factors of unplanned readmission after ACDF to improve the quality of management and prevent increase in healthcare costs.

MATERIALS AND METHODS

We searched the databases of PubMed, EMBASE, Web of Science, and Cochrane Library to identify eligible studies using the searching terms, "readmission" and "ACDF." A total of 10 studies were included.

RESULTS

Among the demographic risk factors, older age [weighted mean difference (WMD), 3.93; 95% confidence interval (CI), 2.30-5.56; p<0.001], male [odds ratio (OR), 1.23; 95% CI, 1.10-1.36; p<0.001], and private insurance (OR, 0.34; 95% CI, 0.17-0.69; p<0.001) were significantly associated with unplanned readmission. Among patient characteristics, hypertension (HTN) (OR, 2.14; 95% CI, 1.41-3.25; p<0.001), diabetes mellitus (DM) (OR, 1.59; 95% CI, 1.20-2.11; p=0.001), coronary artery disease (CAD) (OR, 2.87; 95% CI, 2.13-3.86; p<0.001), American Society of Anesthesiologists (ASA) physical status grade >2 (OR, 2.13; 95% CI, 1.68-2.72; p<0.001), and anxiety and depression (OR, 1.39; 95% CI, 1.29-1.51; p<0.001) were significantly associated with unplanned readmission. Among the perioperative factors, pulmonary complications (OR, 22.52; 95% CI, 7.21-70.41; p<0.001) was significantly associated with unplanned readmission.

CONCLUSION

Male, older age, HTN, DM, CAD, ASA grade >2, anxiety and depression, pulmonary complications were significantly associated with an increased occurrence of unplanned readmission after ACDF.

[Normative values of cervical sagittal alignment according to the whole spine balance: Based on 126 asymptomatic Chinese young adults]

OBJECTIVE

To explore the normal distribution of cervical sagittal alignment and the relationship between cervical alignment and global spine balance in asymptomatic young adults.

METHODS

A cohort of 272 asymptomatic Chinese adults (including 161 males and 111 females, with an average age of (23.2±4.4) years, ranging from 18 to 45 years) were prospectively recruited from November 2011 to December 2014. The C₀-C₂ angle, disk angles from C₂-C₃ to C₆-C₇, vertebral angles from C₃ to C₇, T₁ slope, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), C₂-C₇ sagittal vertical axis (C₂-C₇SVA), center of gravity of head to C₇SVA (CGH-C₇SVA), C₇-S₁SVA were measured and statistically analyzed. All the subjects were categorized with the Roussouly classification and the cervical morphologies were evaluated as lordotic, straight, sigmoid or kyphotic. Spinal sagittal alignment parameters were compared between different sexes and Roussouly classifications with independent student t test, analysis of variance (ANOVA) or Chi-square test. Correlations between cervical sagittal alignment and global spine sagittal alignment were calculated using the Pearson and Spearman correlation coefficient. Linear regression analysis was performed.

RESULTS

Sixty-seven males and 59 females aged from 18 to 30 years old were included in the study. The mean value of C₀-C₇ was 26.0°±12.8°, composed of 15.2°±6.7° for C₀-C₂, 9.1°±12.1° for sum of disk angles from C₂-C₃ to C₆-C₇, and 1.4°±10.2° for sum of vertebral angles from C₃ to C₇. C₂-C₇SVA [(18.6±7.9) mm] and CGH-C₇SVA [(22.9±12.3) mm]were offset ideally by C₇-S₁SVA [(-21.6±31.0) mm]. Males had a larger T₁ slope (P < 0.05) and accordingly, a larger cervical lordosis C₂-C₇ (P < 0.01) and C₀-C₇ angle (P < 0.01) than females. Males had a smaller C₇-S₁SVA (P < 0.01) and accordingly, a smaller CGH-C₇SVA (P=0.165) than females. Significant difference was found between cervical alignment of different Roussouly types (P < 0.01). In general, a larger LL was consistent with a set of larger TK, C₂-C₇angle, C₀-C₇ angle, and vice versa. There was no significant correlation between cervical morphology and the Roussouly classification (Chi-square=10.548, P=0.308). There was significant correlation between cervical alignment and T₁ slope (P < 0.01), TK (P < 0.01). There was significant correlation between adjacent segmental angles from T₁ slope up to C₀-C₂ angle (P < 0.05).

CONCLUSION

Normative values of each vertebral angle and disk angle were established. The cervical lordosis occurred mainly at C₀-C₂ and disk levels, which was influenced by parameters of other parts of the spine, such as T₁ slope, TK and the Roussouly classification. There was significant correlation between adjacent disk angles.

Investigation of Titanium Mesh and Nano-Hydroxyapatite/Polyamide 66 Bone Graft in Cervical Reconstruction of Spondylosis After Sub-Total Vertebral Body Resection

The nano-hydroxyapatite/polyamide 66 (n-HA/PA66) bionic bone column, as a high-performance tissue repair and replacement material, introduced as a high osteo-induction ability agent. Nanomaterial has significantly taken a place in orthopedic surgery, however, the efficacy of using n-HA/PA66 is yet to be established. In this regard, this study evaluated various sagittal parameters (such as imaging measurement) and clinical efficacy in postoperative patients, whom underwent cervical reconstruction surgery due to cervical spondylosis myelopathy (CSM). In this study, total 62 CSM cases were enrolled between October 2016 to March 2020, and were hospitalized for cervical reconstruction surgery. 31 cases were grafted with titanium mesh and 31 cases were grafted with n-HA/P66. The sagittal parameters such as cervical spine lateral radiographs (C_0-2Coob, C_2-7Coob, T1S, CSVA, and TIA) were taken before operation, after operation (within 1 week), 3, 6, and 9 months after operation. In order to evaluate the clinical efficacy, we used JOA scores before, after, 3 months, 6 months and 9 months after operation. Results showed that JOA scores after the re-examination in the two groups (titanium and n-HA/P66) were significantly higher than before the operation, suggesting a well postoperative functional recovery after surgery in both groups; however, there was no significant difference in JOA score and JOA improvement index between the two groups. In regard of angles measurement (C_0-2Cobb, C_2-7Cobb, T1S, CSVA, and TIA), we observed no significant difference between these two groups before and after the operation. In addition, we showed that C_0-2Cobb and C_2-7Cobb angle had a significant positive correlation; and C_0-2Cobb angle is positively correlated with T1S, and negatively correlated with CSVA. Both titanium mesh and n-HA/PA66 can be well improved and maintained within 9 months after surgery with clinical efficacy, however, using n-HA/PA66 might have more benefits.

Analyzing the Significance of T1 Slope minus Cervical Lordosis in Patients with Anterior Cervical Discectomy and Fusion Surgery

Objective

Accurate measurement of T1 slope (a component of T1s minus cervical lordosis [CL]) is often constrained by anatomical limitations. In this situation, efforts should be made to find the exact meaning of T1s-CL and whether there are any alternatives to it.

Methods

We enrolled 117 patients who received two-level anterior cervical discectomy and fusion (ACDF). Occipital slope, C2 slope (C2s), C7 slope (C7s), T1, O-C2 angle (O-C2A), C2-7 angle (C2-7A), O-C7 angle (O-C7A), T1s-CL, C7-T1 angle (C7-T1A), and C2-7 sagittal vertical axis were measured. We determined 16° (T1s-CL) as the reference point for dividing subjects into the mismatch group and the balance group, and a comparative analysis was performed.

Results

The mean value of C7-T1A was constantly maintained within 2.6° peri-operatively. In addition, C2s and T1s-CL showed the same absolute change (Δ|0.8|°). The mean values of T1s-CL of the mismatch and balance groups were 23.0° and 7.6°, respectively. The five factors with the largest differences between the two groups were as follows : C2s (Δ13.3°), T1s-CL (Δ15.4°), O-C2A (Δ8.7°), C2-7A (Δ14.7°), and segmental angle (Δ7.9°) before surgery. Only four factors showed statistically significant change between the two groups after ACDF : T1s-CL (Δ4.0° vs. Δ0.2°), C2s (Δ3.2° vs. Δ0.7°), O-C2A (Δ2.6° vs. Δ1.3°), C2-7A (Δ6.3° vs. Δ1.3°). A very strong correlation between T1s-CL and C2s was also found (r=|0.88–0.96|).

Conclusion

C2s itself may be the essential key to represent T1s-CL. The amounts and directions of change of these two factors (T1s-CL and C2s) were also almost identical. The above phenomenon was re-confirmed once again through the correlation analysis.

Normative values of cervical sagittal alignment according to global spine balance: based on 126 asymptomatic Chinese young adults

PURPOSE

To explore the normal distribution of cervical sagittal alignment and the relationship between cervical alignment and global spine balance in asymptomatic young adults.

METHODS

A total of 67 males and 59 females aged from 18 to 30 years old were recruited from 11/2011 to 12/2014. The C₀-C₂ angle, disk angles from C₂-C₃ to C₆-C₇, vertebral angles from C₃ to C₇, T₁ slope, thoracic kyphosis (TK), lumbar lordosis, pelvic incidence, sacral slope, C₂-C₇ sagittal vertical axis (SVA), center of gravity of head to C₇ SVA (CGH-C₇SVA), C₇-S₁SVA were measured and statistically analyzed. The Roussouly classification was utilized.

RESULTS

Mean value of C₀-C₇ was 26.0° ± 12.8°, composed of 15.2° ± 6.7° for C₀-C₂, 9.1° ± 12.1° for sum of disk angles from C₂-C₃ to C₆-C₇, and 1.4° ± 10.2° for sum of vertebral angles from C₃ to C₇. C₂-C₇SVA (18.6 mm ± 7.9 mm) and CGH-C₇SVA (22.9 mm ± 12.3 mm) were offset ideally by C₇-S₁SVA (-21.6 mm ± 31.0 mm). Significant difference was found between cervical alignment of different Roussouly types (p < 0.01). There was significant correlation between cervical alignment and T₁ slope (p < 0.01), TK (p < 0.01). There was significant correlation between adjacent segmental angles from T₁ slope up to C₀-C₂ angle (p < 0.05).

CONCLUSION

Normative values of each vertebral angle and disk angle were established. The cervical lordosis occurred mainly at C₀-C₂ and disk levels, which was influenced by parameters of other parts of the spine, such as T₁ slope, TK and the Roussouly classification. There was significant correlation between adjacent disk angles.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Cervical balance and clinical outcomes in cervical spondylotic myelopathy treated by three-level anterior cervical discectomy and fusion and hybrid cervical surgery: A CONSORT-compliant study with minimum follow-up period of 5 years

As the technology of combining with fusion and nonfusion procedure, cervical hybrid surgery (HS) is an efficacious alternative for treatment with cervical spondylotic myelopathy. While studies on cervical alignment between 3-level HS and anterior cervical discectomy and fusion (ACDF) were seldom reported. The effects of cervical imbalance on its related clinical outcomes are yet undetermined as well.Patients with cervical spondylotic myelopathy, who underwent 3-level ACDF or HS, were included to compare cervical alignment parameters after surgery and then explore the relationship between cervical balance and clinical outcomes.Forty-one patients with HS (HS group) and 32 patients who with ACDF (ACDF group) were reviewed from February 2007 to September 2013 with the mean follow-up of 90.3 ± 25.5 (m) and 86.3 ± 28.9 (m), respectively. Cervical alignments parameters including the C2 to C7 cervical lordosis (CL), C2 to C7 sagittal vertical axis, T1 slope. and T1SCL (T1 slope minus CL), and the clinical outcomes like neck disability index (NDI) and Japanese Orthopedic Association (JOA) score were measured and recorded preoperatively (PreOP), intraoperatively, and on the first preoperative day and the last follow-up (FFU). The balance and imbalance groupings were sorted based on the T1SCL: T1SCL≤20°,balance; T1SCL > 20°, imbalance.We found significant improvements (P < .001) in NDI and JOA at intraoperatively and FFU after ACDF and HS, and no difference on cervical alignment and clinical outcomes between the 2 procedures on the basis of intergroup comparisons. By between-subgroups comparisons, however, we found significant differences in CL and T1SCL at PreOP (P < .05). Nonetheless, there was no significant difference on the clinical outcomes between balance and imbalance subgroups at FFU at PreOP (P > .05), indicating that the change of T1SCL was not correlated to NDI and JOA at FFU.Both HS and ACDF groups showed significant clinical improvements after surgery. There was no correlation between cervical balance and clinical symptoms.

The Effect of Anterior Cervical Discectomy and Fusion on Cervical Sagittal Vertical Axis and Lordosis with Minimum 2-Year Follow-Up

BACKGROUND

Anterior cervical discectomy and fusion (ACDF) can induce lordosis and improve cervical sagittal vertical axis (SVA), but multilevel ACDF may inadvertently increase cervical SVA because of insufficient lordosis induction.

METHODS

Patients who underwent 1-, 2-, or ≥3-level ACDF in the subaxial spine with minimum 2-year follow up were retrospectively studied. C2-C7 Cobb angle (lordosis), cervical SVA, and T1 slope were measured preoperatively, immediately postoperatively, and at last follow-up.

RESULTS

Inclusion criteria were met by 127 patients. There were no differences in baseline demographics among 1-, 2-, and ≥3-level ACDF groups. Mean follow-up was 43.7 months (range, 24-142 months). Increase of cervical SVA immediately postoperatively was 1.94 mm, -1.44 mm, and 7.25 mm for 1-, 2-, and ≥3-level ACDF (P = 0.041) and at last follow-up was 2.97 mm, 0.70 mm, and 9.32 mm for 1-, 2-, and ≥3-level ACDF (P = 0.026). At last follow-up, 2-level ACDF patients had the greatest decrease in T1 slope (-0.43°) compared with increase of 2.71° for 1-level and 2.84° for ≥3-level patients (P = 0.028). In all 3 groups, segmental (ACDF levels) lordosis, cervical SVA, and T1 slope did not decrease from immediate postoperative to last follow-up. Only 2-level ACDF maintained C2-7 lordosis (2.16°) compared with loss of lordosis in 1-level (-0.84°) and ≥3-level (-2.00°) ACDF (P = 0.008) at last follow-up. Linear regression analysis showed that T1 slope had no relationship with correction of cervical SVA (P = 0.5310) but had a significant correlation with Cobb angle loss of C2-C7 lordosis (P = 0.0016).

CONCLUSIONS

Compared with 1- and 2-level ACDF, ≥3-level ACDF resulted in significant increase of cervical SVA and loss of overall lordosis. Compared with 1- and ≥3-level ACDF, 2-level ACDF had the greatest ability to maintain lordosis. T1 slope had a significant correlation with loss of C2-C7 lordosis after ACDF.

Correlation between kinematic sagittal parameters of the cervical lordosis or head posture and disc degeneration in patients with posterior neck pain

The purpose of this retrospective cross-sectional study was to examine the degrees of the cervical disc degeneration and the parameters of cervical sagittal balance in plain radiographs, representing cervical lordosis or head posture in subjects with posterior neck pain. A total of 113 patients with posterior neck pain with or without radiating pain were analyzed. The kinematic sagittal parameters of cervical radiographs were obtained at the occipito-cervical (O-C2) angle, sagittal Cobb's angles of C1-C2, C2-C7, and sagittal vertical axis (SVA) of C1-C7 and C2-C7. Cervical disc degeneration was evaluated using the sum of Pfirrmann grades and total modified Matsumoto scores calculated from MRI of the cervical spine. A significant positive correlation was found for the C2-C7 angle using the sum of the Pfirrmann grades and total modified Matsumoto scores, whereas the O-C2 angle and the C1-C2 angle were negatively correlated. The sagittal cervical parameters representing cervical kyphosis and jaw lifting posture were found to be significantly correlated with the degree of cervical disc degeneration. These findings suggest that the loss of the natural sagittal lordosis of the cervical spine may contribute to the progression of disc degeneration, rather than the forward head posture.

Analysis of the Variables Affecting the Incidence, Location, and Severity of Cage Subsidence Following Anterior Cervical Discectomy and Fusion Operation

BACKGROUND

For surgical management of degenerative cervical spine disease with myeloradiculopathy, stand-alone cages are frequently used in 1- and 2-level anterior cervical discectomy and fusion (ACDF) operations with a paucity of literature on factors influencing cage subsidence. The aim of this study was to analyze the variables affecting the incidence, location, and severity of cage subsidence.

METHODS

Retrospective review of prospectively collected data of 77 patients (95 levels) undergoing ACDF surgery was conducted. Variables analyzed were age, gender, sagittal alignment, maximum disc height (superior, inferior, and procedure levels), cage size, shape, location, degree of subsidence (minor <2 mm, mild 2-4 mm, moderate 5-7.5 mm, severe >7.5 mm) and location of subsidence.

RESULTS

The incidence of cage subsidence was 34% (32 levels), and 91% were minor or mild. Significantly lower mean maximum height of the inferior disc compared to the nonsubsidence group (5.17 versus 5.96; P = 0.0025) was recorded. Significantly greater incidence of subsidence (40%) was recorded in patients with abnormal cervical spine alignment (focal or diffuse kyphosis) versus 18% with normal alignment (P = 0.02). Greater incidence of subsidence was recorded with more anterior positioned cages (52%; p=0.01). No statistical significance was found for age, gender, superior disc height, or cage shape/size.

CONCLUSIONS

Greater incidence of cage subsidence is significantly associated with a lower maximum disc height of the disc below the operated level (<5.5 mm), abnormal sagittal alignment, and more anteriorly positioned cages. We found that the vast majority of cage subsidence was focal, minor to mild, without having any immediate or late clinical implications in terms of need for revision surgery.

Applicability of cervical sagittal vertical axis, cervical lordosis, and T1 slope on pain and disability outcomes after anterior cervical discectomy and fusion in patients without deformity

OBJECTIVE

Understanding what influences pain and disability following anterior cervical discectomy and fusion (ACDF) in patients with degenerative cervical spine disease is critical. This study examines the timing of clinical improvement and identifies factors (including spinal alignment) associated with worse outcomes.

METHODS

Consecutive adult patients were enrolled in a prospective outcomes database from two academic centers participating in the Quality Outcomes Database from 2013 to 2016. Demographics, surgical details, radiographic data, arm and neck pain (visual analog scale [VAS] scores), and disability (Neck Disability Index [NDI] and EQ-5D scores) were reviewed. Multivariate analysis was used.

RESULTS

A total of 186 patients were included, and 48.4% were male. Their mean age was 55.4 years, and 45.7% had myelopathy. Preoperative cervical sagittal vertical axis (cSVA), cervical lordosis (CL), and T1 slope values were 24.9 mm (range 0-55 mm), 10.4° (range -6.0° to 44°), and 28.3° (range 14.0°-51.0°), respectively. ACDF was performed at 1, 2, and 3 levels in 47.8%, 42.0%, and 10.2% of patients, respectively. Preoperative neck and arm VAS scores were 5.7 and 5.4, respectively. NDI and EQ-5D scores were 22.1 and 0.5, respectively. There was significant improvement in all outcomes at 3 months (p < 0.001) and 12 months (p < 0.001). At 3 months, neck VAS (3.0), arm VAS (2.2), NDI (12.7), and EQ-5D (0.7) scores were improved, and at 12 months, neck VAS (2.8), arm VAS (2.3), NDI (11.7), and EQ-5D (0.8) score improvements were sustained. Improvements occurred within the first 3-month period; there was no significant difference in outcomes between the 3-month and 12-month mark. There was no correlation among cSVA, CL, or T1 slope with any outcome endpoint. The most consistent independent preoperative factors associated with worse outcomes were high neck and arm VAS scores and a severe NDI result (p < 0.001). Similar findings were seen with worse NDI and EQ-5D scores (p < 0.001). A significant linear trend of worse NDI and EQ-5D scores at 3 and 12 months was associated with worse baseline scores. Of the 186 patients, 171 (91.9%) had 3-month follow-up data, and 162 (87.1%) had 12-month follow-up data.

CONCLUSIONS

ACDF is effective in improving pain and disability, and improvement occurs within 3 months of surgery. cSVA, CL, and T1 slope do not appear to influence outcomes following ACDF surgery in the population with degenerative cervical disease. Therefore, in patients with relatively normal cervical parameters, augmenting alignment or lordosis is likely unnecessary. Worse preoperative pain and disability were independently associated with worse outcomes.

Correlation between cervical lordosis and cervical disc herniation in young patients with neck pain

Abnormal cervical curvature and cervical disc herniation are closely related to neck pain and should be taken into account before any treatment. However, studies have rarely reported on the correlation between cervical lordosis and cervical disc herniation in patients with neck pain. Therefore, in this study, we collect young neck pain patients with abnormal cervical curvature to evaluate the relationship between cervical lordosis and cervical disc herniation.Three hundred patients below 40 years old with neck pain were enrolled. Patient sex, age, apical vertebra, segment of intervertebral disc protrusionl, sagittal diameter of spinal duramater, saggital diameter of spinal canal, height of disc space were recorded, and the cervical curvature, and degree of cervical spinal cord compression (G/F ratio) were calculated. The change of degree of disc herniation and degree of cervical spinal cord compression were analyzed in different cervical curvature groups. Further more, collected these patients who had improved cervical curvature over a period of time, to compare the changes of degree of disc herniation, G/F ratio, and height of disc space.The median age of patients with kyphosis was lower than those with lordosis and straight cervical spine. The degree of disc herniation was higher in the straight and kyphosis groups compared to the lordosis group. Cervical lordosis was inversely correlated with the degree of disc herniation and positively with G/F ratio. Cervical curvature was significantly affected by sex, age, and the degree of disc herniation. With the improvement of cervical lordotic curvature, the degree of disc herniation decreased and height of disc space increased.The degree of disc herniation and cervical spinal cord compression are inversely correlated to cervical lordosis in young neck pain patients, and the degree of disc herniation and height of disc space can recover with the recovery of cervical lordotic curvature. These findings may indicating a link between cervical curvature and degenerative changes which have important clinical implications.

[Effect of anterior cervical discectomy and decompression with different fusion segments on sagittal spine-pelvis balance]

Objective

To explore the effect on sagittal spine-pelvis balance of different fusion segments in anterior cervical discectomy and fusion (ACDF).

Methods

The clinical data of 326 patients with cervical spondylotic myelopathy, treated by ACDF between January 2010 and December 2016, was retrospectively analysed. There were 175 males and 151 females with an average age of 56 years (range, 34-81 years). Fusion segments included single segment in 69 cases, double segments in 85 cases, three segments in 90 cases, and four segments in 82 cases. Full spine anterolateral X-ray films were performed before operationand at 12 months after operation. The spine-pelvis parameters of fusion segments were measured and compared. The parameters included C 0-2 Cobb angle, C 2-7 Cobb angle, C 2-7 sagittal vertical axis (C 2-7 SVA), T 1 slope (T 1S), thoracic inlet angle (TIA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), sacral slope (SS), C 7 sagittal vertical axis (C 7 SVA), T 1 pelvic angle (TPA). The Japanese Orthopaedic Association (JOA) score of cervical spine and visual analogue scale (VAS) scores of pain of cervical spine and upper extremity were compared before operation and at 12 months after operation. Pearson correlation analysis was performed on LL, PI, SS, C 7 SVA, and TPA before and after operation to evaluate the changes of spine-pelvis fitting relationship after ACDF.

Results

All 326 patients were followed up 12-32 months (mean, 18.5 months). During the follow-up period, internal fixator was in place, and no spinal cord nerve or peripheral soft tissue injury was found. JOA scores and cervical VAS scores improved significantly at 12 months after operation ( P<0.05), no significant difference was found in VAS scores of upper extremity when compared with preoperative scores ( P>0.05). The preoperative cervical VAS scores and the postoperative JOA scores at 12 months had significant differences between groups ( P<0.05). At 12 months after operation, there was no significant difference in sagittal spine-pelvis parameters in the single segment group compared with preoperative ones ( P>0.05); but the C 0-2 Cobb angle, C 2-7 Cobb angle, C 2-7 SVA, T 1S, TIA, C 7 SVA, and TPA in the double segments, three segments, and four segments groups were significant larger than preoperative ones ( P<0.05). The C 0-2 Cobb angle, C 2-7 Cobb angle, T 1S, C 7 SVA, and TPA among 4 groups had significant differences before operation and at 12 months after operation ( P<0.05). At 12 months after operation, the changes of C 7 SVA and TPA in the double segments, three segments, and four segments groups were significantly larger than those in the single segment group ( P<0.05). PI had positive correlations with LL and SS before and after operation in 4 groups ( P<0.05).

Conclusion

Normal fitting relationship between lumbar spine and pelvis in physiological state also exists in patients with cervical spondylotic myelopathy, and ACDF can not change this specific relationship. In patients with cervical spondylotic myelopathy, the sagittal spine-pelvis sequence do not change after ACDF single-level fusion, while the sagittal spine-pelvis balance change after double-level and multi-level fusion.

[Comparison of the long-term outcomes of total arthroplasty and anterior spinal fusion in the treatment of cervical degenerative disc disease: a metaanalysis]

AIM

The study aim was to perform a meta-analysis based on the results of randomized clinical trials comparing long-term outcomes of total intervertebral disc arthroplasty (TA) and anterior cervical spinal fusion (ACSF) in the surgical treatment of cervical degenerative disc disease.

MATERIAL AND METHODS

We searched Pubmed, EMBASE, ELibrary, and Cochrane Library databases for randomized clinical trials reported between 2008 and August 2018. The relative risk and 95% confidence interval were calculated for dichotomous variables; for continuous variables, we used the standardized mean difference and their 95% CI with application of a random effects model.

RESULTS

The metaanalysis involved 9 randomized controlled clinical trials including the long-term outcomes of surgical treatment in 2,439 patients. A pooled analysis of the data showed that regression of neurological symptoms (p<0.00001), improvement in the quality of life of patients (Neck Disability Index), and lower pain severity (visual analogue scale for upper extremities) were significantly more often observed (p=0.02) in the group of TA patients. In addition, the TA technique was characterized by a statistically significantly lower rate of re-surgery (p<0.0005) and degeneration of the superjacent segment (p<0.0001), with the rate of adverse events being slightly increased (p=0.04).

CONCLUSION

Compared to anterior cervical spinal fusion, TA of cervical intervertebral discs is characterized by significantly better clinical efficacy in patients with cervical degenerative disc disease in the long-term postoperative follow-up.

Comparison of Spinal Curvatures in the Sagittal Plane, as Well as Body Height and Mass in Polish Children and Adolescents Examined in the Late 1950s and in the Early 2000s

BACKGROUND Humans are exposed to various stimuli which lead to somatic modifications and changes in body posture, negatively affecting many of its characteristics. The purpose of this study was to assess significant alterations which occurred in selected morphological features and spinal curvatures in children and adolescents over a period of 40 years. MATERIAL AND METHODS The total of 7041 subjects, aged 4-18 years (mean age 11.3 years) were included in the study, which was designed to compare measurements performed in year 1959 (Group 1, n=3235 individuals) and in year 2003 (Group 2, n=3806 individuals). The children were examined for body height, body mass, as well as thoracic and lumbar curvatures. In 1959, the measurements were carried out using a spherodorsimeter, while in 2003, the CQ System photogrammetry was used, producing corresponding results. The Mann-Whitney U test and the Student's t-test were used for statistical analysis. RESULTS The findings showed a significant decrease in the angle of lumbar lordosis and in sacral inclination as well as an increase in body height and mass, particularly in prepubertal children. On the other hand, the angle of thoracic kyphosis and the partial angles of physiological spinal curvatures changed only to a small degree over the 40-year period. CONCLUSIONS This study provides evidence related to changes which occurred during the relevant period of over 40 years, namely a decrease in both the angle of lumbar lordosis and the sacral inclination angle, as well as an increase in body height and mass. These changes should be taken into consideration in selecting norms and standards applied in healthcare services, and the findings suggest it is necessary to regularly update such standards.

The Influences of Different Ratios of Biphasic Calcium Phosphate and Collagen Augmentation on Posterior Lumbar Spinal Fusion in Rat Model

PURPOSE

To determine the influence of different ratios of hydroxyapatite (HA)/beta tricalcium phosphate (β-TCP) and collagen augmentation for posterior lumbar fusion in a rat model.

MATERIALS AND METHODS

We generated a posterior lumbar fusion model in 50 rats and divided it into five groups of equal number as follows; 1) autologous bone graft as group A, 2) 70% HA+30% β-TCP as group B, 3) 70% HA+30% β-TCP+collagen as group C, 4) 30% HA+70% β-TCP as group D, and 5) 30% HA+70% β-TCP+collagen as group E. Rats were euthanized at 12 weeks after surgery and fusion was assessed by manual palpation, quantitative analysis using microCT and histology.

RESULTS

The score of manual palpation was significantly higher in group C than group E (3.1±1.1 vs. 1.8±0.8, p=0.033). However, in terms of microCT analysis, group D showed significantly higher scores than group B (5.5±0.8 vs. 3.1±1.1, p=0.021). According to quantitative volumetric analysis, 30% HA+70% β-TCP groups (group D and E) showed significantly reduced fusion mass at 12 weeks after surgery (123±14.2, 117±46.3 vs. 151±27.3, p=0.008, 0.003, respectively). Collagen augmentation groups revealed superior results in terms of both microCT score and histologic grade.

CONCLUSION

A 7:3 HA/β-TCP ratio with collagen augmentation rather than a 3:7 HA/β-TCP ratio could be a more favorable graft substitute for lumbar spinal fusion. There was positive role of collagen as an adjunct for spinal bone fusion process.