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

Lee, Ho Jin,You, Soon Tae,Sung, Jae Hoon,Kim, Il Sup,Hong, Jae Taek The Korean Neurosurgical Society 2021 Journal of Korean neurosurgical society Vol.64 No.6

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.

T1 시상각이 큰 환자에서 경추 만곡이 경추간판 퇴행에 미치는 영향

홍성하,이승환,박병문,송경섭,임성태 대한척추외과학회 2018 대한척추외과학회지 Vol.25 No.2

Study Design: Retrospective evaluation. Objectives: To analyze the effect of cervical lordosis on cervical disc degeneration in patients with a high T1 slope. Summary of Literature Review: The T1 slope is known to be a parameter that may be very useful in evaluating sagittal balance. We previously reported that a low T1 slope was a potential risk factor for cervical spondylosis, especially in the C6-7 cervical segment. However, no study has analyzed the effect of cervical lordosis in patients with a high T1 slope (>25) on cervical disc degeneration. Materials and Methods: Seventy-seven patients with a high T1 slope who underwent cervical spine MRI in our orthopedic clinic were enrolled. Patients were divided into 2 groups according to cervical compensation. The radiologic parameters obtained from radiography and cervical spine MRI were compared between the uncompensated group (cervical lordosis <25) and the compensated group (cervical lordosis ≥25). Results: In the uncompensated group, the average degeneration grade of each segment was 2.72 (±0.70) in C2-3, 3.00 (±0.76) in C3-4, 3.02 (±0.91) in C4-5, 3.37 (±0.95) in C5-6, and 2.95 (±0.98) in C6-7. The average degeneration grade of each segment in the compensated group was 2.38 (±0.78) in C2-3, 2.38 (±0.60) in C3-4, 2.62 (±0.60) in C4-5, 2.82 (±0.72) in C5-6, and 2.41 (±0.74) in C6-7. The degeneration grade was significantly higher in the uncompensated group than in the compensated group for all cervical segments. The risk of high-grade degeneration of C3-4 was significantly higher in the uncompensated group (odds ratio = 6.268; 95% CI, 2.232-17.601; p<.001). Conclusions: Patients with a high T1 slope without compensation of cervical lordosis had a higher grade of degeneration in all cervical segments. 연구 계획: 후향적 연구목적: T1 시상각이 큰 환자들에서 경추 만곡에 의한 보상이 경추간판의 퇴행성 변화에 미치는 효과를 분석하고자 하였다. 선행 연구문헌의 요약: T1 시상각은 시상 균형을 평가하는 유용한 지표로 알려져 있다. 저자들은 T1 시상각이 낮은 경우 제 6-7 경추간판의 퇴행성 변화가 많다고 보고한 바 있다. 그러나 T1 시상각이 큰 환자(>25)에서 경추 만곡의 보상이 경추간판의 퇴행성 변화에 미치는 영향에 대해서는 분석하지않았다. 대상 및 방법: 정형외과에 내원하여 경추부 MRI를 촬영한 환자들 중 T1 시상각이 25도 보다 큰 77명의 환자를 대상으로 하였다. 환자들을 경추 만곡의보상에 따라 비보상군(경추 만곡<25)과 보상군(경추 만곡≥25)으로 분류하였다. 경추간판의 퇴행성 변화는 Miyazaki 분류에 따라 다섯 등급으로 분류하였다. 두 군간의 방사선학적 지표와 MRI상의 추간판 퇴행성 변화를 비교하였다. 결과: 비보상군에서 경추간판의 평균 퇴행 등급은 제 2-3경추간에서 2.72, 제 3-4경추간에서 3.00, 제 4-5경추간에서 3.02, 제 5-6경추간에서 3.37, 제6-7경추간에서 2.95로 나타났다. 보상군에서 경추간판의 평균 퇴행 등급은 제 2-3경추간에서 2.38, 제 3-4경추간에서 2.38, 제 4-5경추간에 서 2.62, 제5-6경추간에서 2.82, 제 6-7경추간에서 2.41로 나타났다. 모든 경추 분절에서 퇴행성 변화가 비보상군에서 보상군에 비해 유의하게 높았다. 제 3-4경추간판에서 3등급 이상의 심한 퇴행 등급의 비율 역시 비보상군에서 유의하게 높았다(OR 6.268, 95% CI 2.232-17.601, p<0.001). 결론: T1 시상각이 25도보다 큰 환자들에서 경추 만곡의 보상이 없는 경우 경추간판 전체에서 퇴행성 변화가 많은 것으로 나타났다. 약칭 제목: 경추 만곡에 의한 보상

The Use of T1 Sagittal Angle in Predicting Cervical Disc Degeneration

양봉석,이수건,송경섭,윤상필,장근,이재철,문성환,이환모,이승환 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.5

Study Design: Retrospective evaluation. Purpose: To analyze the effect of T1 slope on degree of degeneration in patients with cervical disc degeneration. Overview of Literature: The T1 slope is well known parameter that may be very useful in evaluating sagittal balance. There are no reports on the analysis of the relationship between T1 slope and cervical disc degeneration. We hypothesized that T1 slope has an effect on the degree of cervical degeneration. Methods: Sixty patients who had cervical spine magnetic resonance imaging (MRI) in our orthopedic clinic were enrolled. Patients were divided into two groups according to T1 slope. Radiologic parameters obtained from radiography and cervical spine MRI were compared between low T1 slope group (≤25) and high T1 slope group (>25). Results: Among low T1 slope group, average degeneration grade of each cervical segment was 2.65 in C2–3, 2.50 in C3–4, 2.62 in C4–5, 3.23 in C5–6, and 2.81 in C6–7. And that of high T1 group was 2.35 in C2–3, 2.32 in C3–4, 2.59 in C4–5, 2.79 in C5–6, and 2.32 in C6–7. Grade of degeneration of low T1 group was significantly higher, as compared with high T1 group in C5–6 (p =0.028) and C6–7 (p =0.009). Percentage of high grade degeneration of more than grand III was 65.4% in low T1 group and 32.4% in high T1 group (p =0.018). Risk of high grade degeneration of C6–7 was significantly higher in low T1 group (odds ratio, 5.63; 95% confidence interval, 1.665–19.057; p =0.005). Conclusions: Patients with low T1 slope had higher grade of degeneration regardless of age and gender. Low T1 slope is a potential risk factor of cervical spondylosis especially in the C6–7 cervical segment.

Clinical Impact and Correlations of Odontoid Parameters Following Multilevel Posterior Cervical Fusion Surgery

이재구,현승재,양승헌,김기정 대한척추신경외과학회 2022 Neurospine Vol.19 No.4

Objective: C2 slope (C2S), a cervical parameter mathematically approximated as T1 slope minus cervical lordosis (T1S–CL), predicts functional improvement in cervical deformity patients. Nonetheless, C2S is a positional parameter based only on the horizontal axis. The current study aims to introduce novel odontoid parameters and establish their relationships with patient-reported health-related quality of life (HRQoL). Methods: Lateral plain radiographs of 32 adults who underwent multilevel posterior cervical fusion were analyzed. The odontoid parameters included odontoid incidence (OI), C2S, odontoid tilt (OT), and gravity line-C2 distance (GL-C2), while the cervical parameters were the Cobb angle at C0–1, C1–2, C0–2, C2–7, C2–7 sagittal vertical axis (cSVA), T1 slope, and T1S–CL. The range of motion (ROM) of the occipito-atlantoaxial complex was measured in flexion and extension plain radiographs. Scores on the Neck Disability Index (NDI) and visual analogue scale (VAS) for axial neck (VASn) and arm pain were measured. Results: Compared to asymptomatic subjects, patients had larger C2S, cSVA, and T1S– CL, and smaller OT. Preoperatively, OI was significantly correlated with the ROM of C1–2 (r = 0.37, p < 0.05) and C0–2 (r = 0.46, p < 0.01). OT and C2S had significant correlations with the C0–1, C1–2, and C0–2 angles, GL-C2, and T1S–CL. Postoperative NDI scores were significantly correlated with OI (r = -0.40, p < 0.05) and OT (ρ = -0.37, p < 0.05). VASn was significantly correlated with GL-C2 (r = -0.35, p < 0.05). Conclusion: The odontoid parameters were significantly correlated with established cervical parameters and HRQoL measures. OI is a constant parameter representing the individual's compensatory reservoir at the upper cervical spine.

T1 Slope and Cervical Sagittal Alignment on Cervical CT Radiographs of Asymptomatic Persons

박지훈,조철범,송준호,김석우,하윤,오재근 대한신경외과학회 2013 Journal of Korean neurosurgical society Vol.53 No.6

Objective : We performed a retrospective analysis of medical records and radiographic images of patients who never underwent spinal treatment including diagnosis. The objective of this study is to explain the biomechanical and physiologic characteristics of cervical alignment related to thoracic inlet angle including T1 slope changes in each individual. Methods : We reviewed the cervical CT radiographs of 80 patients who visited ENT outpatient clinic without any symptom, diagnosis and treatment of cervical spine from January 2011 to September 2012. All targeted people were randomized without any prejudice. We assessed the data-T1 slope, Cobb’s angle C2-7, neck tilt, sagittal vertical axis (SVA) C2-7 and thoracic inlet angle by the CT radiographs. Results : The relationships between each value were analyzed and we concluded that Cobb’s angle C2-7 gets higher as the T1 slope gets higher, while the SVA C2-7 value decreases. Conclusion : We propose that the T1 slope is background information in deciding how much angle can be made in the cervical spinal angle of surgical lordotic curvature, especially severe cervical deformity.

T1 Slope and Cervical Sagittal Alignment on Cervical CT Radiographs of Asymptomatic Persons

Park, Ji Hoon,Cho, Chul Bum,Song, Jun Ho,Kim, Seok Woo,Ha, Yoon,Oh, Jae Keun The Korean Neurosurgical Society 2013 Journal of Korean neurosurgical society Vol.53 No.6

Objective : We performed a retrospective analysis of medical records and radiographic images of patients who never underwent spinal treatment including diagnosis. The objective of this study is to explain the biomechanical and physiologic characteristics of cervical alignment related to thoracic inlet angle including T1 slope changes in each individual. Methods : We reviewed the cervical CT radiographs of 80 patients who visited ENT outpatient clinic without any symptom, diagnosis and treatment of cervical spine from January 2011 to September 2012. All targeted people were randomized without any prejudice. We assessed the data-T1 slope, Cobb's angle C2-7, neck tilt, sagittal vertical axis (SVA) C2-7 and thoracic inlet angle by the CT radiographs. Results : The relationships between each value were analyzed and we concluded that Cobb's angle C2-7 gets higher as the T1 slope gets higher, while the SVA C2-7 value decreases. Conclusion : We propose that the T1 slope is background information in deciding how much angle can be made in the cervical spinal angle of surgical lordotic curvature, especially severe cervical deformity.

Accuracy and Reliability of X-ray Measurements in the Cervical Spine

Catarina Marques,Emma Granström,Anna MacDowall,Nuno Canto Moreira,Martin Skeppholm,Claes Olerud 대한척추외과학회 2020 Asian Spine Journal Vol.14 No.2

Study Design: This study is a post hoc analysis of a multicenter prospective randomized controlled trial which compared artificial disc replacement and anterior cervical discectomy and fusion. Purpose: Useful radiographic parameters for assessing cervical alignment include the Cobb angles, T1 slope (T1S), occipitocervical inclination (OCI), K-line tilt (KLT), and cervical sagittal vertical axis (cSVA). This study aimed to determine measurement accuracy and reliability for these parameters. Overview of Literature: Various authors have assessed repeatability by comparing different methods of measurement, but knowledge of measurement error and minimal detectable change is scarce. Methods: We evaluated 758 lateral cervical radiographs. One medical student and one spine surgeon (i.e., measured ×2 within 4 weeks) independently measured the parameters obtaining 5,850 values. Standard error of measurement (SEm) and minimum detectable change (MDC) were calculated for each parameter. The accuracy and reliability of the Cobb angle measurements were calculated for the different types of angles: cervical lordosis, prosthesis angle, segmental angle with two bone surfaces (SABB), and segmental angle with one bone and one metal surface. Reliability was determined with intraclass correlation coefficient (ICC). Results: SEm was 1.8° and MDC was 5.0° for the Cobb angle, with an intraobserver/interobserver ICC of 0.958/0.886. All the different subtypes of Cobb angles had an ICC higher than 0.950, except SABB (intraobserver/interobserver ICC of 0.922/0.716). The most accurate and reliable measurement was for KLT. Conclusions: This study provides normative data on SEm and MDC for Cobb angles, T1S, KLT, OCI, and cSVA in cervical lateral radiographs. Reliability was excellent for all parameters except SABB (e.g., good).

도로 기하구조에 따른 차량 Microphone 위치별 소음 영향 분석

문학룡,한대철,강원평 한국도로학회 2013 한국도로학회논문집 Vol.15 No.4

PURPOSES: The purpose of study is to understand the characteristic of driving noise from the front and rear tire for effective active noise cancellation application. METHODS : As literature review, noise measurement methods were reviewed. Noise measurement conducted at three kind of section by road slope using CPX(Close Proximity Method). Noise data was compared by total sound pressure level and 1/3 octave band frequency sound pressure level. Also, each section was compared by T-test using SPSS. RESULTS : In the case of the uphill section, it was shown that the sound pressure level of the front tire at Sugwang-Ri and Sinchon-RI sections was higher than that of the rear tire in low and high frequency band. In the case of high slope section of Sangsaek-Ri, the sound pressure level of the front tire was higher than that of the rear tire in high frequency. Also, in the case of the downhill section, it was shown that the sound pressure level of the front tire at Sugwang-Ri and Sinchon-RI sections was higher than that of the rear tire in low frequency band. However, the sound pressure levels of both the front and rear tires were approximately the same in the high slope section of Sangsaek-Ri. The result of T-test showed that total sound pressures of the front and rear tires were not different from each other in the case of high slope and high speed. CONCLUSIONS: Road slope was not an important variable for effective active noise cancellation.

Changes in Regional and Global Sagittal Parameters of the Spine during Growth in the Pediatric Population

이춘성,황창주,조재환,이동호,양재준,박세한 대한척추외과학회 2022 대한척추외과학회지 Vol.29 No.3

Study Design: Cross-sectional study. Objectives: To demonstrate normative values for various parameters of spinal sagittal global balance in the pediatric population and elucidate whether these parameters change during growth. Summary of Literature Review: While sagittal parameters for adults have been thoroughly evaluated, relatively few studies have reported normal values and changing trends of sagittal parameters in the pediatric population. Materials and Methods: A total of 200 patients aged 5–20 years were evaluated. Cervical lordosis, thoracic kyphosis, lumbar lordosis, pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), pelvic incidence–lumbar lordosis (PI-LL), C2–C7 sagittal vertical axis (SVA), C7 SVA, T1 pelvic angle (T1PA), and the spinosacral angle (SSA) were assessed. Results: Significant positive correlations were found between age and PI (r=0.297, p<0.001), SS (r=0.184, p=0.009), and PT (r=0.203, p=0.004). Among the global sagittal parameters, T1PA (r=0.345, p<0.001) demonstrated a significant association with age, whereas C7 SVA (r=−0.053, p=0.464) and SSA (r=−0.029, p=0.194) were not significantly associated. Furthermore, PI-LL was significantly smaller in the ≥12-year age group than that in the ≤11-year age group (p=0.037). Conclusions: In conclusion, PI, PT, and SS increase during growth owing to the increasing size of the pelvis. T1PA accordingly increases with an increase in pelvic parameters, whereas no other global sagittal parameters, such as C7 SVA or SSA, change during childhood. The changing trends and normative values of each parameter demonstrated in the present study should be considered when planning long-level fusion operations for pediatric patients.

Odontoid Incidence: A Novel Cervical Parameter Influencing Cervical Alignment From Top to Bottom

이재구,현승재,김기정 대한척추신경외과학회 2022 Neurospine Vol.19 No.2

Objective: By using angulation of the axis itself, this study aims to define and analyze odontoid incidence (OI) and odontoid tilt (OT) as novel cervical alignment parameters and investigate their correlations with cervical alignment. Methods: Novel and existing parameters were measured with whole-spine lateral plain radiographs and EOS images of 42 adults without cervical symptoms. The correlations of OI, OT, C2 slope (C2S), and T1 slope (T1S) were calculated. Results: The OI, OT, and C2S showed significant correlations with C2–7 angle (r = 0.43, r = -0.42, r = 0.62, respectively) and C0–2 angle (r = -0.33, r = 0.48, r = -0.61, respectively). OI, OT, T1S were independent predictors of the C2–7 angle in univariate regression analysis (adjusted-R2 = 0.17, R2 = 0.15, R2 = 0.28, respectively). OI, OT, and T1S were independent predictors in the multivariable regression analysis with estimated standardized coefficients of 0.36, -0.67, -0.69, respectively (adjusted- R2 = 0.80, p < 0.001). Regarding the C0–2 angle, OI and OT were independent predictors in the univariate regression analysis (adjusted-R2 = 0.08, R2 = 0.21, respectively). Conclusion: OI, OT, and C2S had significant correlations with cervical alignment. As the pelvic incidence, the OI is the only anatomical and constant parameter that could be used as a reference point related to the cervical spine from the rostral end. The study results may serve as baseline data for further studies on the alignment and balance of the cervical spine.