Mean C2 Research Articles

How cervical and cervicothoracic scoliosis influence the atlantoaxial joint.

Children with cervical or cervicothoracic congenital scoliosis are limited in their ability to compensate for the main curve of the deformity because there are only a few mobile segments in their cervical spine. Over the years, we have frequently observed coronal atlantoaxial dislocation (CAAD) in a lateral direction (from left to right or vice versa) in these patients. It was anticipated that CAAD might compensate for the horizontal position of the head, and it is hypothesized that CAAD depends on the degree of scoliotic deformity. Thus, the aim of our study was to investigate whether there is a correlation between CAAD and scoliosis parameters in these patients. Retrospective analysis was performed based on CAT scans and preoperative X-rays of patients with cervical and cervicothoracic scoliosis with an apex between C4 and T6. Seventeen patients, with a mean age of 7.25 years, who were 9 girls and 8 boys, and who were treated between 2006 and 2022 were included. Cobb`s angle of the main curve (CA-MC), Cobb`s angle of the secondary curve (CA-SC), and T1-, C2- and UEV (upper end vertebra) tilt were measured on whole-spine radiographs in the standing position. The CAAD was measured via coronal CAT scan reconstruction and defined as the difference in the distances of the lateral masses to the midline of the axis. Pearson`s linear correlation coefficients (r) were determined using SPSS to evaluate correlations between CAAD and the measured parameters. p < 0.05 indicated statistical significance. CAAD toward the convex region in patients with scoliosis was typically observed; the mean CAAD was 3mm ± 3.7mm. The mean CA-MC was 46° ± 13°, the mean CA-SC was 16° ± 9.6°, the mean T1 tilt was 17° ± 8.8°, the mean C2 tilt was 9°± 8.8°, and the mean UEV tilt was 24° ± 7.2°. There was a strong linear correlation between CAAD and CA-MC (r = 0.784, p < 0.001), C2 tilt (r = 0.745; p < 0.001), and UEV tilt (r = 0.519; p = 0.033). There was no correlation between CAAD and either CA-SC or T1 tilt. Children with cervical or cervicothoracic scoliosis tend to have a CAAD toward the convexity of the scoliosis that correlates to CA-MC, C2-tilt, and UEV-tilt. CAAD may be seen as a compensatory mechanism to keep the head in a horizontal position. Severe or progressive CAAD may result in destruction of the atlantoaxial joint, including severe complaints, thus necessitating close follow-up and possibly early surgical treatment. Moreover, CAAD might be a useful additional radiographic parameter to be checked in future scoliosis studies.

Acylcarnitines metabolism in depression: association with diagnostic status, depression severity and symptom profile in the NESDA cohort.

Acylcarnitines (ACs) are involved in bioenergetics processes that may play a role in the pathophysiology of depression. Previous genomic evidence identified four ACs potentially linked to depression risk. We carried forward these ACs and tested the association of their circulating levels with Major Depressive Disorder (MDD) diagnosis, overall depression severity and specific symptom profiles. The sample from the Netherlands Study of Depression and Anxiety included participants with current (n = 1035) or remitted (n = 739) MDD and healthy controls (n = 800). Plasma levels of four ACs (short-chain: acetylcarnitine C2 and propionylcarnitine C3; medium-chain: octanoylcarnitine C8 and decanoylcarnitine C10) were measured. Overall depression severity as well as atypical/energy-related (AES), anhedonic and melancholic symptom profiles were derived from the Inventory of Depressive Symptomatology. As compared to healthy controls, subjects with current or remitted MDD presented similarly lower mean C2 levels (Cohen's d = 0.2, p ≤ 1e-4). Higher overall depression severity was significantly associated with higher C3 levels (ß=0.06, SE = 0.02, p = 1.21e-3). No associations were found for C8 and C10. Focusing on symptom profiles, only higher AES scores were linked to lower C2 (ß=-0.05, SE = 0.02, p = 1.85e-2) and higher C3 (ß=0.08, SE = 0.02, p = 3.41e-5) levels. Results were confirmed in analyses pooling data with an additional internal replication sample from the same subjects measured at 6-year follow-up (totaling 4141 observations). Small alterations in levels of short-chain acylcarnitine levels were related to the presence and severity of depression, especially for symptoms reflecting altered energy homeostasis. Cellular metabolic dysfunctions may represent a key pathway in depression pathophysiology potentially accessible through AC metabolism.

Do key measurement parameters derived from specific cervical vertebral segments differ between lordotic and non-lordotic cervical spine alignments? A study of asymptomatic young adults

BackgroundMeasurement parameters derived from specific cervical vertebral segments (e.g., C2 slope) can provide clinicians with important information on cervical sagittal balance and guide pre- and post-surgical decision-making processes. It is unclear however, what constitutes typical values for these types of measurements in an asymptomatic population of young adults, whether values change depending upon the classification of the cervical spine's global alignment, and if any non-lordotic cervical subtypes display values that are comparable to those reported for pre-surgery patients. MethodsNeutral lateral cervical radiographs of 150 asymptomatic participants (18–30 years) were taken. Global cervical alignment was classified as lordotic or one of four non-lordotic subtypes using a multi-method subtyping protocol. Four key measurement parameters - the anterior translation of the head measure (ATHM), C0–C2 angle, C2 slope, and C7 slope – were derived from specific cervical segments. Independent samples t-tests were used to compare lordotic and non-lordotic groups. ResultsThere was considerable variation in the four key measurement parameters amongst this asymptomatic population of young adults. Thirty-four percent of the sample were classified as lordotic and 66% were classified as non-lordotic. There was a significant difference (p ≤ 0.0125) between lordotic and non-lordotic groups for the C0–C2 angle, C2 slope and C7 slope. There was no difference between groups for the ATHM (p ≥ 0.0125). Within the non-lordotic group, the global-kyphotic (GK) subtype had the largest mean C2 slope, largest mean C0–C2 angle, and smallest mean C7 slope. ConclusionsLong term prospective investigations are required to determine whether possible biomarkers (alignment parameters/radiological measurements) for spinal degenerative changes can be identified so that early interventions can be put in place to try and reduce the impact of neck pain on society.

Proximal and distal reciprocal changes following cervical deformity malalignment correction.

Hyperextension of C0-2 is a debilitating compensatory mechanism used to maintain horizontal gaze, analogous to high pelvic tilt in the lumbopelvic complex to maintain an upright posture. This study aims to investigate the impact of cervical deformity (CD) correction on this hyperextension. The authors hypothesize that correction of cervical sagittal malalignment allows for relaxation of C0-2 hyperextension and improved clinical outcomes. A retrospective review was conducted of a multicenter database of patients with CD undergoing spinal realignment and fusion caudal to C2 and cephalad to the pelvis. Range of motion (ROM) and reserve of extension (ROE) were calculated across C2-7 and C0-2. The association between C2-7 correction and change in C0-2 ROE was investigated while controlling for horizontal gaze, followed by stratification into ΔC2-7 percentiles. Sixty-five patients were included (mean age 61.8 ± 9.6 years, 68% female). At baseline, patients had cervical kyphosis (C2-7, -11.7° ± 18.2°; T1 slope-cervical lordosis mismatch, 38.6° ± 18.6°), negative global alignment (sagittal vertical axis [SVA] -12.8 ± 71.2 mm), and hyperlordosis at C0-2 (mean 33.2° ± 11.8°). The mean ROM was 25.7° ± 17.7° and 21.3° ± 9.9° at C2-7 and C0-2, respectively, with an ROE of approximately 9° for each segment. Limited C0-2 ROM and ROE correlated with the Neck Disability Index (r = -0.371 and -0.394, p < 0.01). The mean number of levels fused was 7.0 ± 3.1 (24.6% anterior, 43.1% posterior), with 87.7% undergoing at least an osteotomy. At 1 year, mean C2-7 increased to 5.5° ± 13.4°, SVA became neutral (11.5 ± 54.8 mm), C0-2 hyperlordosis decreased to 27.8° ± 11.7°, and thoracic kyphosis (TK) increased to -49.4° ± 18.1° (all p < 0.001). Concurrently, mean C0-2 ROM increased to 27.6° ± 8.1° and C2-7 ROM decreased significantly to 9.0° ± 12.3° without a change in ROE. Controlling for horizontal gaze, change in C2-7 lordosis significantly correlated with increased TK (r = -0.617, p < 0.001), decreased C0-2 (r = -0.747, p < 0.001), and increased C0-2 ROE (r = 0.550, p = 0.002). CD correction can significantly impact cephalad and caudal compensation in the upper cervical and thoracic spine. Restoration of cervical alignment resulted in increased C0-2 ROE and TK and was also associated with improved clinical outcome.

Fullfield and extrafoveal visual evoked potentials in healthy eyes: reference data for a curved OLED display

PurposeVisual evoked potentials (VEP) present an important diagnostic tool in various ophthalmologic and neurologic diseases. Quantitative response data varied among patients but are also dependent on the recording and stimulating equipment. We established VEP reference values for our setting which was recently modified by using a curved OLED display as visual stimulator. Distinction is made between fullfield (FF) and extrafoveal (EF) conduction, and the effect of sex, age and lens status was determined.MethodsThis prospective cross-sectional study included 162 healthy eyes of 162 test persons older than 10 years. A fullfield pattern-reversal visual evoked potential (FF-PR-VEP) with two stimulus sizes (ss) (20.4′ and 1.4°) as well as an extrafoveal pattern onset–offset VEP (EF-P-ON/OFF-VEP) (ss 1.4° and 2.8°) was derived in accordance with the International Society for Clinical Electrophysiology of Vision guidelines. Amplitudes and latencies were recorded, and the mean values as well as standard deviations were calculated. Age- and sex-dependent influences and the difference between phakic and pseudophakic eyes were examined. A subanalysis of EF-P-ON/OFF-VEP and fullfield pattern onset–offset VEP (FF-P-ON/OFF-VEP) was performed. A 55-inch curved OLED display (LG55EC930V, LG Electronics Inc., Seoul, South Korea) was used as visual stimulator.ResultsMean P100 latency of the FF-PR-VEP was 103.81 ± 7.77 ms (ss 20.4′) and 102.58 ± 7.26 ms (ss 1.4°), and mean C2 latency of the EF-P-ON/OFF-VEP was 102.95 ± 11.84 ms (ss 1.4°) and 113.58 ± 9.87 ms (ss 2.8°). For all stimulation settings (FF-PR-VEP, EF-P-ON/OFF-VEP), a significant effect of age with longer latencies and smaller amplitudes in older subjects and higher amplitudes in women was observed. We saw no significant difference in latency or amplitude between phakic and pseudophakic eyes and between EF-P-ON/OFF-VEP and FF-P-ON/OFF-VEP.ConclusionsA curved OLED visual stimulator is well suited to obtain VEP response curves with a reasonable interindividual variability. We found significant effects of age and gender in our responses but no effect of the lens status. EF-P-ON/OFF-VEP tends to show smaller amplitudes.

Increased Neck Tilt/T1 slope ratio may play an important role in patients with cervical kyphosis

BackgroundIn previous studies, we demonstrated that the T1 slope (T1s) is associated with clinical outcomes, but the results were not specific for individuals. A recent study suggested that an increased pelvic tilt (PT)/sacral slope (SS) ratio may play an important role in the degeneration of lumbar scoliosis and pathogenesis of lumbar spondylolisthesis. Therefore, we aimed to explore the role of neck tilt (NT)/T1s in patients with cervical kyphosis.MethodsIn total, the data of 36 kyphosis patients who underwent anterior cervical hybrid decompression and fusion (ACHDF) for multilevel (3 levels) cervical spondylotic myelopathy were retrospectively analyzed. The radiographic measurements included the T1s, NT, C2–7 Cobb angle, and C2–7 sagittal vertical axis (SVA). The visual analog scale (VAS) and neck disability index (NDI) scores were used to determine the clinical prognosis. Pearson’s correlation coefficient was calculated to assess the relationships among preoperative imaging examination parameters.ResultsThe mean C2–7 Cobb angle was − 5.93 ± 3.00° before surgery, 9.67 ± 6.61° after surgery, and 7.91 ± 8.73° at the follow-up. The preoperative NT/T1s ratio was positively correlated with the ΔC2–7 Cobb angle (r = 0.358, p < 0.05) and negatively correlated with the preoperative C2–7 Cobb angle (r = -0.515, p < 0.01) and preoperative C2–7 SVA (r = -0.461, p < 0.01). The linear regression model indicated a positive correlation between the preoperative NT/T1s ratio and the ΔC2–7 Cobb angle (R2 = 0.122).ConclusionsThe preoperative NT/T1s ratio may be positively correlated with changes in postoperative cervical spine curvature (Cobb angle). The NT/T1s ratio may be worthy of increased attention among sagittal parameters.

Effects of a reduced in‐office bleaching protocol with 37.5% hydrogen peroxide on effectiveness and tooth sensitivity: A double‐blind randomized clinical trial

This randomized clinical trial evaluated the effectiveness and tooth sensitivity (TS) of 37.5% hydrogen peroxide (37.5HP) in-office bleaching with reduced protocol. Forty participants with shade mean C2 or darker for the six maxillary anterior teeth were randomly allocated into two treatment groups (n=20): two (37.5HP2) or three (37.5HP3) 8min applications/clinical session. Three clinical sessions were performed with a 1week interval. Color evaluations were done with a spectrophotometer at baseline and 1week post-bleaching. TS was measured during and up to 48 h after bleaching using a five-point numeric rating scale. Color change was evaluated by Student's t-test for independent samples. The absolute risk and intensity of TS were analyzed by Fisher's and Mann-Whitney/Friedman tests (p < 0.05). Both treatment groups resulted in a significant tooth whitening 1week post-bleaching (p < 0.001). There were no significant differences between 37.5HP2 and 37.5HP3 for ΔE*ab , ΔE00 and ∆WID . Also, there were not differences between groups regarding high absolute risk (p=1.0) and low intensity of TS at all time assessments (p > 0.7). The in-office bleaching with two 37.5% HP applications produced the same whitening degree, risk and intensity of TS to that performed with three gel applications. Clinicians should opt to use a neutral 37.5% HP in-office bleaching gel for two 8min applications/clinical session because produces the same whitening effectiveness, risk and low intensity of TS as the protocol proposed by manufacturer (three 8min applications).

The importance of preoperative T1 slope for determining proper postoperative C2\u20137 Cobb\u2019s angle in patients undergoing cervical reconstruction

BackgroundThis study aimed to explore the relationship among different cervical sagittal parameters in asymptomatic volunteers and the correlation between surgical efficacy and difference of presumed and actual postoperative C2–7 Cobbs’s angle (C2–7COBB), which was calculated based on preoperative T1 slope (T1S) in patients undergoing cervical reconstruction.MethodsIn total, 158 inpatients with cervical spondylosis and 274 asymptomatic volunteers were retrospectively reviewed. Cervical sagittal parameters, such as C2–7COBB, T1S, thoracic inlet angle (TIA), and neck tilt (NT), were compared. Then, the correlation among these parameters was analyzed in asymptomatic volunteers, and a regression equation between T1S and C2–7COBB was established and used to analyze the correlation among the Japanese Orthopaedic Association (JOA) score improvement, the sagittal parameters, and the difference between presumed and actual postoperative C2–7COBB in patients after cervical reconstruction.ResultsThe mean T1S, C2–7COBB, and TIA were significantly decreased in patients (P < 0.01). T1S and NT had a strong correlation with TIA (P < 0.01). T1S demonstrated a moderate correlation with C2–7COBB in asymptomatic volunteers (r = 0.569, P < 0.01). A regression equation had been established as C2–7COBB = 0.742 × T1S − 0.866. The mean C2–7COBB and JOA score improved significantly (P < 0.05) postoperatively. Moreover, the JOA improvement rate showed a significant negative correlation with the difference in the presumed and actual postoperative C2–7COBB (r = − 0.696, P < 0.01).ConclusionOur study successfully established a regression equation for calculating postsurgical C2–7COBB based on the correlation between T1S and C2–7COBB in asymptomatic volunteers. The regression equation could be used for guiding surgeons to accomplish an ideal postsurgical C2–7COBB for patients with cervical spondylosis.

Cough Reflex Sensitivity in Asthmatic Children.

New knowledge about the neural aspects of cough has revealed a complex network of pathways that initiate cough. The effect of inflammation on cough neural processing occurs at multiple peripheral and central sites within the nervous system. Evidence exists that direct or indirect neuroimmune interaction induces a complex response, which can be altered by mediators released by the sensory or parasympathetic neurons and vice versa. The aim of this study was to clarify changes of cough reflex sensitivity - the activity of airway afferent nerve endings - in asthmatic children.25 children with asthma and 15 controls were submitted to cough reflex sensitivity measurement - capsaicin aerosol in doubling concentrations (from 0.61 to 1250 µmol/l) was inhaled by a single breath method. Concentrations of capsaicin causing two (C2) and five coughs (C5) were reported. Asthmatic children' (11 boys and 14 girls, mean age 9 ± 1 yrs) cough reflex sensitivity (geometric mean, with the 95 % CI) for C2 was 4.25 (2.25-8.03) µmol/l vs. control C2 (6 boys and 9 girls, mean age 8 ± 1 yrs) was 10.61 (5.28-21.32) µmol/l (p=0.024). Asthmatic children' C5 was 100.27 (49.30-203.93) µmol/l vs. control C5 56.53 (19.69-162.35) µmol/l (p=0.348). There was a statistically significant decrease of C2 (cough threshold) in the asthmatic patients relative to controls (p-value for the two-sample t-test of log(C2) for the one-sided alternative, p-value = 0.024). The 95 % confidence interval for the difference of the mean C2 in asthma vs. control, [1.004, 6.207]. For C5, the difference was not statistically significant (p-value = 0.348). There was a statistically significant decrease of cough reflex sensitivity (the activity of airway afferent nerve endings) - C2 value in the asthmatic children relative to controls.

Morphometry of the C2 Pedicle and Lamina in Thai Patients.

Background:Traumatic upper cervical spine leads to instability and neurological deficit. At present, C2 (axis) pedicle or lamina screws for fixation are popular because further external immobilization is not needed. However, these techniques demand experience inserting the screws and carry the risk of vertebral artery or spinal cord injury. In some patients, the C2 screws cannot be inserted because of limited C2 size.Objective:To determine the width, length, height, and angle in the C2 pedicle and lamina in the Thai population.Materials and Methods:Patient data were collected from the Picture Archiving and Communication System at the Faculty of Medicine, Prince of Songkla University from January 2016 to December 2017. The C2 parameters, i.e., width, length, height, and angle of the pedicle and lamina were recorded.Results:The CT C-spine scans of 270 patients were enrolled. The mean Thai C2 pedicle dimensions were width 5.51 mm, length 23.78 mm, angle 39.04°, and height 8.64 mm. The mean C2 lamina dimensions were width 5.88 mm, length 32.17 mm, angle 49.46°, and height 12.27 mm. Twenty-four patients from the 270 patients (8.8%) had a pedicle width <3.5 mm but all patients had a lamina width ≥3.5 mm.Conclusion:In the Thai samples, 8.8% had a C2 pedicle width <3.5 mm which would not allow insertion of screws; however, they could be replaced with lamina screws since the lamina width was ≥3.5 mm. In this study, all of the patients who could not be inserted pedicle can be replaced with lamina screws inserted.

Predictive formula of cervical lordosis in asymptomatic young population

BackgroundNot a large number of previous studies have reported the normal sagittal balance of the cervical spine and physiological cervical lordosis (CL) has not been clearly defined yet.MethodsThis was a prospective radiological analysis of asymptomatic subjects. The following cervical sagittal parameters were measured: CL, thoracic inlet angle (TIA), T1 slope (T1S), neck tilt (NT), and C2–7 sagittal vertical axis (C2–7 SVA). The Pearson correlation test was calculated, and the stepwise multiple regression analysis was conducted by using the CL (dependent variable) and the other cervical sagittal parameters (independent variables) to determine the best sets of predictors. A paired sample t test was conducted between the predicted and measured values.ResultsThe mean age of 307 participants was 24.54 + 3.07. The mean CL, TIA, T1S, NT, and C2–C7 SVA was 17.11° ± 6.31°, 67.87° ± 7.78°, 25.84° ± 5.36°, 42.53° ± 6.68°, and 14.60 ± 8.20 mm, respectively. The formula was established as follows: CL = 0.762 × T1S − 0.392 × C2–C7 SVA + 0.25 × TIA − 13.795 (R = 0.812, R2 = 0.660) (stepwise multiple regression) and CL = 0.417 × TIA − 11.193 (R = 0.514, R2 = 0.264) (simple linear regression). There was no statistical difference between the predicted CL and the measured CL (t = 0.034, P = 0.973).ConclusionsThere was a significant correlation between CL and other cervical sagittal parameters, including TIA, T1S, NT, and C2–C7 SVA in asymptomatic Chinese population. The results of this study may serve as a normal reference value for the study of asymptomatic population.

Postoperative Kyphosis in Cervical Spondylotic Myelopathy: Cut-off Preoperative Angle for Predicting the Postlaminoplasty Kyphosis.

A prospective cohort study. This study aimed to investigate the relationship between preoperative cervical sagittal alignment and postoperative kyphosis in patients with cervical spondylotic myelopathy (CSM) and to determine the cut-off angle for predicting the postlaminoplasty kyphosis. There have been several reports describing a cervical kyphosis after laminoplasty. However, there has been no study on the cut-off angle for predicting the postoperative kyphosis in a large series of patients with CSM. A total of 1025 consecutive patients with CSM (642 men and 383 women; mean age, 64.4 yr; range, 23-93 yrs) who underwent laminoplasty were included. The average follow-up period was 30.0 months. Radiography was performed before the surgery and at final follow-up. The cervical alignment with neutral view was measured by using the Cobb method. An alignment of C2-7 lordotic angle more than 0° was defined as lordosis and C2-7 lordotic angle less than 0° was defined as kyphosis. The incidence of postoperative kyphosis was evaluated on lateral radiographs. In all patients, the mean C2-7 alignment in the neutral position was 11.5° lordotic before surgery and 14.2° lordotic at final follow-up. In the patient without preoperative kyphotic alignment, receiver operating characteristic curve of preoperative C2-7 lordotic angle showed 7° as a predictor for the postlaminoplasty kyphosis (area under the curve = 0.75, P < 0.0001). Among the preoperatively 720 patients with lordosis more than 7°, postoperative kyphosis was observed in 20 patients (2.8%), whereas in the preoperatively 191 patients with lordosis less than 7°, postoperative kyphosis was seen in 28 patients (14.7%). The cut-off value of preoperative C2-7 lordotic angle for predicting the postlaminoplasty kyphosis was 7° in CSM patient without preoperative kyphotic alignment. 3.

Is the Pretransplant C 2 an Optimum Predictor of Posttransplant dose for Tacrolimus in Renal Transplantation Patients?

Aim: The study evaluated whether a single dose pretransplant 2-h tacrolimus concentration (C2) could predict the post-transplantation trough concentration (C0). Materials &amp; methods: C2 concentration of tacrolimus was measured after single-dose administration (0.1 mg/kg) in 20 patients, 4–7 days prior to renal transplantation. Tacrolimus C0 monitoring was done on post-transplant day 2, 5, 10, 15 and 30. Results: The mean C2 was 21.79 ± 16.83 ng/ml (4.25–69.46) and the mean C0 obtained 48 h after transplant was 10.2 ± 6.27 (1.63–22.07) ng/ml. The Spearman correlation between C2 and C0 was 0.71 (p &lt; 0.01). Conclusion: Pretransplant C2 could explain only 50% of the total variation in the post-transplant dose requirement hence it may not be sole predictor of the post-transplant dose.

Random matrix-improved estimation of covariance matrix distances

Given two sets x1(1),…,xn1(1) and x1(2),…,xn2(2)∈Rp (or ℂp) of random vectors with zero mean and positive definite covariance matrices C1 and C2∈Rp×p (or ℂp×p), respectively, this article provides novel estimators for a wide range of distances between C1 and C2 (along with divergences between some zero mean and covariance C1 or C2 probability measures) of the form 1p∑i=1nf(λi(C1−1C2)) (with λi(X) the eigenvalues of matrix X). These estimators are derived using recent advances in the field of random matrix theory and are asymptotically consistent as n1,n2,p→∞ with non trivial ratios p∕n1<1 and p∕n2<1 (the case p∕n2>1 is also discussed). A first “generic” estimator, valid for a large set of f functions, is provided under the form of a complex integral. Then, for a selected set of atomic functions f which can be linearly combined into elaborate distances of practical interest (namely, f(t)=t, f(t)=ln(t), f(t)=ln(1+st) and f(t)=ln2(t)), a closed-form expression is provided. Besides theoretical findings, simulation results suggest an outstanding performance advantage for the proposed estimators when compared to the classical “plug-in” estimator 1p∑i=1nf(λi(Cˆ1−1Cˆ2)) (with Cˆa=1na∑i=1naxi(a)xi(a)⊤), and this even for very small values of n1,n2,p. A concrete application to kernel spectral clustering of covariance classes supports this claim.

A novel concept of posterior decompression and instrumented fusion with selective lordotic correction for cervical ossification of the posterior longitudinal ligament

PurposeThe recovery rate of Japanese Orthopedic Association (JOA) score with K-line (−) cervical ossification of the posterior longitudinal ligament (OPLL) for posterior decompression with in-situ fusion (PDF) tends to be lower than that of anterior decompression with fusion (ADF). However, ADF is a technically demanding operation and has ADF-specific complications. This prospective report introduced a novel concept of PDF with selective lordotic correction as well as prophylactic foraminal decompression. MethodsSix consecutive patients (four men and two women; mean age, 61.8 years) were included. PDF was performed, attempting to create cervical lordosis to acquire a posterior shift of the spinal cord, while preventing postoperative C5 palsy by prophylactic facetectomy and selective lordotic correction. ResultsThe mean recovery rate of JOA score at the final follow-up was 70.9 ± 20.3%. The mean C2–C7 angle preoperatively and at final follow-up was 5.5 ± 3.9° and 12.2 ± 4.8°, respectively. No symptomatic nerve root palsy, except one case with transient C7 root iatrogenic palsy, was found. ConclusionsA novel concept of PDF with selective lordotic correction obtained recovery rates of JOA scores comparable to those of ADF. We believe that this method can improve PDF outcomes in patients with K-line (−) OPLL.

Ten-Year Results of Reconstruction for Rheumatoid Cervical Spine Lesions and Occurrence Factor of Subaxial Subluxation.

Study DesignRetrospective chart review.PurposeThis study evaluated long-term surgical outcomes of computer-assisted reconstruction using transarticular or cervical pedicle screws for cervical spine lesions caused by advanced rheumatoid arthritis (RA).Overview of LiteratureWe routinely employ C1–C2 transarticular and cervical pedicle screw instrumentation to reconstruct advanced and unstable RA cervical lesions. However, few reports are available on the long-term results of surgical reconstruction for rheumatoid cervical disorders, particularly regarding cervical pedicle screw fixation.MethodsSix subjects (all female) with RA cervical lesions who underwent atlantoaxial or occipitocervical fixation and were followed for at least 10 years were retrospectively studied. A frameless, stereotactic, optoelectronic, computed tomography-based image guidance system was used for correct screw placement. Variables including the Japanese Orthopaedic Association score, EuroQol, Ranawat value, and C2–C7 angle before and 2, 5, and 10 years after surgery were assessed along with the occurrence of subaxial subluxation (SAS).ResultsMean age at initial surgery was 58.2±7 years (range, 51–68 years), and mean follow-up period was 141±11 months (range, 122–153 months). Lesions included atlantoaxial subluxation (AAS, n=2) and AAS+vertical subluxation (n=4). Mean C2–C7 lordotic angle before and 2, 5, and 10 years after surgery was 20.1°±6.1°, 21.0°±4.0°, 18.8°±4.7°, and 17.8°±5.3°, respectively. SAS did not occur in cases maintaining the C2–C7 lordotic angle. In two cases where the C2–C7 lordotic angle declined from 5 years postoperatively, SAS occurred at the C2–C3 level in one and at the C4–C5 level in the other, both of which required reoperation.ConclusionsPatients with rheumatoid cervical lesions who undergo atlantoaxial or occipitocervical fixation using C1–C2 transarticular or pedicle screws carry a risk of SAS for up to 10 years postoperatively, which may require reoperation.

The Nature of the Shared Environment.

While a standard part of twin modeling, the magnitude of shared environment (c2) is rarely examined by comparing estimates obtained using other methods. To clarify these effects on familial resemblance, we estimated c2 for 20 diverse phenotypes in: (i) monozygotic and dizygotic twins, (ii) all step-siblings, and (iii) reared together and apart half-siblings, ascertained from the Swedish general population. The mean c2 estimates (± 95% CIs) differed across methods and were higher from twins (0.18; 0.13-0.23) than from the step (0.12; 0.09-0.14) and half-sibs (0.09; 0.06-0.13). c2 estimates correlated moderately across these three methods (ICC = + 0.28). When step-siblings from blended (each sib biologically related to one parent) and adoption-like families (one sib offspring of both parents and one of neither), were examined separately, resemblance was much lower in the latter. We need to clarify the range of environmental processes now considered together under the term "shared environment."

The C2 Pedicle Width, Pars Length, and Laminar Thickness in Concurrent Ipsilateral Ponticulus Posticus and High-Riding Vertebral Artery: A Radiological Computed Tomography Scan-Based Study.

Study DesignRetrospective radiological study.PurposeWe aimed to determine the prevalence of ponticulus posticus (PP) and high-riding vertebral artery (HRVA) occurring simultaneously on the same side (PP+HRVA) and in cases of PP+HRVA, to assess C2 radio-anatomical measurements for C2 pars length, pedicle width, and laminar thickness.Overview of LiteraturePP and HRVA predispose individuals to vertebral artery injuries during atlantoaxial fixation. In cases of PP+HRVA, the construct options thus become limited.MethodsConsecutive computed tomography scans (n=210) were reviewed for PP and HRVA (defined as an internal height of <2 mm and an isthmus height of <5 mm). In scans with PP+HRVA, we measured the ipsilateral pedicle width, pars length, and laminar thickness and compared them with controls (those without PP or HRVA).ResultsPP was present in 14.76% and HRVA in 20% of scans. Of the 420 sides in 210 scans, PP+HRVA was present on 13 sides (seven right and six left). In scans with PP+HRVA, the C2 pars length was shorter compared with controls (13.69 mm in PP+HRVA vs. 20.65 mm in controls, p<0.001). The mean C2 pedicle width was 2.53 mm in scans with PP+HRVA vs. 5.83 mm in controls (p<0.001). The mean laminar thickness was 4.92 and 5.48 mm in scans with PP+HRVA and controls, respectively (p=0.209).ConclusionsThe prevalence of PP+HRVA was approximately 3% in the present study. Our data suggest that, in such situations, C2 pedicle width and pars length create important safety limitations for a proposed screw, whereas the translaminar thickness appears safe for a proposed screw.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P109. Effect of cervical deformity correction on stenosis, spinal canal and cord compression utilizing magnetic resonance and computed tomography imaging modalities

BACKGROUND CONTEXT Cervical deformity (CD), often degenerative in etiology, is typically accompanied by the onset of symptomatic spinal stenosis. It is hypothesized that causation of spinal canal and cord compressive forces is multifactorial, with reduction of compressive forces being a key driver of symptom alleviation. PURPOSE To quantify and assess the relationship between postoperative changes to sagittal alignment, canal or cord decompression, and symptom alleviation. STUDY DESIGN/SETTING Retrospective review of a prospective CD database. PATIENT SAMPLE Twenty-seven CD patients. OUTCOME MEASURES Stenotic Levels, Pavlov Ratio, Spinal Canal Cross-Sectional Area, Spinal Cord Cross-Sectional Area, mJOA scores, NSR Neck Pain scores. METHODS ConsecutiveCD patients (C2–C7 Cobb>10°, CL>10°, cSVA>4 cm, or CBVA>25°) undergoing multilevel fusion. Those with pre-operative magnetic resonance imagings (MRIs) and 1-year post-operative cervical MRI or CT scans were assessed for spinal canal and cord cross-sectional area, using dedicated imaging software at each interspace and body from C2–C7, and the apex of deformity[apex]. Stenotic vertebral levels were measured using Pavlov's method from C2 to C7: a ratio of canal to vertebral body RESULTS A total of 27 patients were included (61±10 years, 64.2%F, BMI: 29.6±8.0, CCI: 0.81±1.1). BL radiographic assessment: TS-CL: 34.0±17.2; Cervical Lordosis: −1.6±15.7; cSVA: 36.3±18.5; PI-LL: 0.12±19.3; Pelvic Tilt: 20.1±11.6; SVA: 0.94±71.6. Ames classification deformity descriptors: C: 57.7%, CT: 30.8%, T: 7.7%, S: 3.8%. Surgical approach included 7.4% anterior, 51.9% posterior, 40.7% combined; 23(79%) patients had decompression procedures, all patients had an osteotomy, and mean fusion length was 8.6±4.2 levels. Following surgical intervention, mean canal cross-sectional area (267.5 mm2 vs. 320.5 mm2, p=.025), apex canal cross-sectional area (240 mm2 vs. 301.3 mm2, p=.039), and apex cord cross-sectional area (60.6 mm2 vs. 70.1 mm2, p=.019) all increased (regardless of decompression procedure status). Decreased stenotic levels (4.11vs. 2.97, p=.003) and improved apex pavlov ratios (0.76vs. 0.91, p=.032) were also observed. Cervical kyphosis correction correlated with Δ in stenotic levels (rs: 0.664, p=.001), Δ in mean C2–C7 pavlov ratio (rs: 0.601, p=.004), and Δ in apex canal area (rs: 0.562, p=.024). TS-CL correction correlated with Δ in stenotic levels (rs: 0.751, p CONCLUSIONS Sagittal realignment was associated with reduction of symptomatic stenosis and cord compressive forces, regardless of decompression status. Stenotic level reduction was associated with improved mJOA scores, while alleviation of dynamic radial compressive forces at the apex of deformity significantly reduced patient neck pain.

Surgical Outcomes of Cervical Myelopathy in Patients with Athetoid Cerebral Palsy: A 5-Year Follow-Up.

Study DesignObservational cohort study.PurposeTo assess the surgical outcomes of posterior decompression and fusion for cervical myelopathy in patients with athetoid cerebral palsy.Overview of LiteraturePatients with athetoid cerebral palsy demonstrate involuntary movements and develop severe cervical spondylosis with kyphosis. In these patients, surgery is often performed at an early age because of myelopathy. A few studies have reported about the long-term outcomes of surgical treatment; however, they contain insufficient information.MethodsFrom 2003 to 2008, 13 patients with cervical myelopathy due to athetoid cerebral palsy underwent posterior fusion surgery and were included in this study. The Japanese Orthopaedic Association (JOA) score, neck disability index (NDI), C2–7 angle on radiography, and need for additional surgical treatment were examined at 1 and 5 years postoperatively.ResultsThe mean C2–7 angle was −10.5°±21.1° preoperatively and was corrected to −2.9°±13.5° immediately postoperatively. This improvement was maintained for 5 years. The JOA score was 9.5±2.5 preoperatively and 12.2±1.7 at the 5-year follow-up. NDI was 17±6.9 preoperatively and 16±7.5 at the 5-year follow-up. Patient satisfaction with surgery on a 100-point scale was 62.2±22.5 at the 5-year follow-up. Three patients needed additional surgery for loosening of screws. These results demonstrate good surgical outcomes for posterior fusion at 5 years.ConclusionsPosterior decompression and fusion should be considered a viable option for cervical myelopathy in patients with athetoid cerebral palsy.