Clinical outcome of percutaneous endoscopic lumbar decompression in treatment of elderly patients with lumbar spinal stenosis: a matched retrospective study.

PURPOSE: This retrospective cohort study aimed to evaluate the efficacy and safety of percutaneous endoscopic lumbar decompression (PELD) in elderly patients with lumbar spinal stenosis (LSS). STUDY DESIGN: A matched retrospective study. SETTING: The research was conducted in Beijing Chaoyang Hospital, Capital Medical University, China. METHODS: This study included patients treated with PELD for LSS from September 2016 to September 2020. Patients with LSS aged ≥ 80 years were screened according to the inclusion and exclusion criteria as the study group, and then the same number of patients with LSS aged 50-80 years were matched according to gender, stenosis type, and surgical segment as the control group. Preoperative patient status was assessed using the Charlson comorbidity index (CCI) and the American Society of Anesthesiologists (ASA) physical status classification score. Clinical outcomes were assessed using the visual analog scale (VAS), Oswestry Disability Index (ODI) scores, modified Macnab criteria, radiological parameters and complication rates. RESULTS: A total of 624 LSS patients met the screening criteria between September 2016 and September 2020, with 47 LSS patients ≥ 80 years old serving as the study group. Forty-seven LSS patients aged 50-80 years were matched to the study group according to gender, stenosis type, and stenosis segment. The CCI score (1.77 ± 1.67) and ASA classification (2.62 ± 0.74) of the study group were significantly higher than the CCI score (0.66 ± 0.96) and ASA classification (1.28 ± 0.54) of the control group, and the difference was statistically significant. Compared with preoperative data, postoperative ODI, leg pain VAS scores and back pain VAS scores were significantly improved in both groups (p < 0.05). However, no significant difference was found between two groups in preoperative and postoperative ODI, leg pain VAS scores and back pain VAS scores (p > 0.05). The operation time and postoperative hospital stay in control group were significantly lower than those in study (p < 0.05), but there was no significant difference in blood loss between the two groups (p > 0.05). Besides, overall radiological parameters were comparable in elder and younger patients (p > 0.05), and disc height (DH), lumbar lordosis and segmental lordosis decreased after two year follow-up in both groups (p < 0.05). In addition, complication rates were similar between the two groups (p > 0.05), and no serious complications and deaths were found. LIMITATIONS: Single-centre retrospective design, non-randomized sample, small sample size. CONCLUSION: Although elderly LSS patients (≥ 80 years old) are less fit and have more comorbidities, satisfactory outcomes can be achieved with PELD, comparable to those of LSS patients < 80 years old, and without increased complications.

Comparative efficacy and complications of single and dual growing rods for early-onset scoliosis: an updated meta-analysis.

PURPOSE: This updated meta-analysis aimed to compare single and dual growing rods, including both traditional growing rod and magnetically controlled growing rod (MCGR) used in the treatment of early-onset scoliosis (EOS) with regard to deformity correction, spinal growth, and complications. METHODS: This meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using articles extracted from PubMed, EMBASE databases, and Cochrane Library databases. Only articles reporting the complications and the imaging parameters before and after growing rods in the patients diagnosed with EOS were included. We extracted and statistically analyzed the data deemed relevant for this study, and used the Newcastle-Ottawa Scale to assess the risk of bias in each study. Data synthesis and statistical analyses were performed using R software. RESULTS: Fifteen eligible articles containing 409 participants (n = 185, single growing rods; n = 224, dual growing rods) were identified. The meta-analysis found no significant differences in the preoperative and postoperative major Cobb angle, T1-S1 distance, thoracic kyphosis, and coronal balance between single and dual rods groups. The final follow-up major Cobb angle (P = 0.01; standardized mean difference, - 0.42 [95% confidence interval (CI), - 0.74 to - 0.10]; I2 = 23%) was significantly smaller in dual rods group than single-rod group. However, no significant differences in the correction rate of angle (major Cobb angle and kyphosis angle) and changes in the T1-S1 distance between the two groups were observed. Moreover, there were no significant differences in the metalwork failure, infection, or proximal junctional kyphosis between single and dual rods groups. However, total complications (P = 0.03; risk ratio (RR), 0.79 [95% CI, 0.63-0.98]; I2 = 29%) and distraction failure in MCGR (P = 0.04; RR, 0.38 [95% CI, 0.14-0.98]; I2 = 11%) were significantly lower in dual rods group than single-rod group. CONCLUSION: This updated meta-analysis found that patients with dual growing rods had fewer complications, especially distraction failure in MCGR, than those with single growing rod. However, none of deformity correction, spinal growth, or other complications differed between single and dual growing rods. Therefore, we believe that dual growing rods do not provide strong advantages over single growing rod in the treatment of EOS.

Morphometric change in intervertebral foramen after percutaneous endoscopic lumbar foraminotomy: an in vivo radiographic study based on three-dimensional foramen reconstruction.

PURPOSE: This study aimed to perform in vivo three-dimensional (3D) quantitative measurements of morphometric changes in the foramen in patients with lumbar foraminal stenosis (LFS) undergoing percutaneous endoscopic lumbar foraminotomy (PELF) and investigate the relationship between anatomical changes in the foramen and clinical outcomes. METHODS: We retrospectively reviewed consecutive patients with LFS treated with PELF between January 2016 and September 2020 at our centre. Clinical outcomes were evaluated. Foraminal volume (FV) and foraminal minimal area (FMA) were calculated using a novel vertebral and foramen segmentation method. A comparison of the anatomical parameters of the foramen were conducted between the satisfied and unsatisfied groups divided based on the modified MacNab criteria. RESULTS: A total of 26 eligible patients with a mean follow-up of 3.6 years were enrolled. A significant increase was found in overall FV (71.5%) from 1.436 ± 0.396 to 2.464 ± 0.719 cm3 (P < 0.001) and FMA (109.5%) from 0.849 ± 0.207 to 1.780 ± 0.524 cm2. All clinical outcomes were significantly improved (P < 0.001) after PELF. No significant difference was found in changes in neither FV nor FMA between the two groups. CONCLUSION: Clinical results and foraminal dimensions improved significantly after PELF, indicating that PELF was a prominent technique suitable for LFS because of the direct decompression at impingement structures. No relationship was found between morphometric changes and clinical outcomes, revealing that full-scale endoscopic decompression is necessary and adequate for LFS, and unsatisfactory outcomes are less likely to result from decompression procedure.

Radiographic adjacent segment degeneration and risk factors for osteoporotic vertebral compression fractures treated with percutaneous kyphoplasty.

PURPOSE: In this study, we aimed to clarify whether osteoporotic vertebral compression fracture (OVCF) following percutaneous kyphoplasty (PKP) was associated with a high risk for radiographic adjacent segment degeneration (ASD) and to identify the risk factors for radiographic ASD in these individuals. METHODS: We retrospectively reviewed consecutive patients with OVCFs who underwent PKP at our institution between November 2015 and January 2021. The incidence of radiographic ASD was calculated and specific subgroups of ASD were identified. Univariate and multivariate analyses of demographic, clinical baseline, and radiologic data were performed to identify risk factors associated with radiographic ASD. RESULTS: With a mean follow-up time of 27.3 months, a total of 95 eligible patients were enrolled. The incidence of radiographic ASD distinguished from natural degeneration was 52.6%. Patients with OVCFs who underwent PKP had a high risk of developing radiographic ASD, particularly disc degeneration. Intradiscal cement leakage (odds ratio [OR], 5.706; 95% confidence interval [CI], 2.039-15.970; P = 0.001) and preoperative disc height (OR, 0.681; 95% CI, 0.518-0.895; P = 0.006) were identified as independent risk factors. CONCLUSION: Patients with OVCFs who underwent PKP were more likely to develop radiographic ASD, and their progression was distinguished from natural degeneration. Disc degeneration was the most common type of degeneration. Intradiscal cement leakage and preoperative disc height were identified as independent risk factors for developing radiographic ASD in these patients. Further validation through prospective multicenter studies is required.

Characteristics of paraspinal muscle fat infiltration in asymptomatic Chinese adults: a cross-sectional study.

Background: Paraspinal muscle fat infiltration is closely related to the occurrence and development of lumbar spine disorders and postoperative complications. This study aimed to explore the effects of age, sex, muscle, and level on paraspinal muscle fat infiltration among Chinese adults to identify the best single level of assessing whole-level paraspinal muscle fat infiltration and to define the standardized identification thresholds for paraspinal muscle fat infiltration by means of magnetic resonance imaging. Methods: This was a single-center, cross-sectional study conducted on 336 asymptomatic Chinese volunteers aged 20 to 69 years recruited from Beijing and surrounding communities through designed advertisements from May 2022 to October 2022. The fat signal fraction of multifidus (FSFMF), erector spinae (FSFES), psoas major (FSFPM), and the sum of multifidus, erector spinae, and psoas major (FSFTotal) at lumbar levels L1-L5 were measured with magnetic resonance imaging. The Student t-test and Mann-Whitney test were performed, and Pearson correlations and intraclass correlation coefficients were determined. Subgroups were compared using analysis of variance followed by a post hoc Bonferroni test or Kruskal-Wallis test. Results: FSFTotal (14.02%±4.71% vs. 10.34±4.08%; P<0.001), FSFMF (21.14%±6.77% vs. 16.21%±6.26%; P<0.001), and FSFES (15.97%±5.56% vs. 12.37%±4.80%; P<0.001) were higher in females than in males and increased with age and lumbar level, whereas FSFPM did not significantly differ by age (all P values >0.05) or sex (P=0.12) and showed a decreasing trend from L1 to L5. The FSFTotal at L4 showed both the strongest correlation (Pearson correlation coefficient =0.95; P<0.001) and agreement (intraclass correlation coefficient =0.92; P<0.001) with the whole-level FSFTotal. Pathological paraspinal muscle fat infiltration identification thresholds of FSFTotal, FSFMF, FSFES, and FSFPM were 10.0-33.9%, 19.2-47.4%, 16.2-43.6%, and 4.8%, respectively, in each age (range, 20-69 years) and sex group. Conclusions: In asymptomatic Chinese adults, paraspinal muscle fat infiltration can be influenced by age, sex, muscle type, and location. The L4 level can serve as an optimal substitution in whole-level fat infiltration measurement. We present the first data concerning the identification thresholds of pathological paraspinal muscle fat infiltration, which will provide a valuable resource for researchers in the field.

Efficacy of Repeat Percutaneous Endoscopic Lumbar Decompression for Reoperation of Lumbar Spinal Stenosis: A Retrospective Study.

Purpose: To evaluate the efficacy of repeat percutaneous endoscopic lumbar decompression (PELD) in lumbar spinal stenosis (LSS) reoperation. Patients and Methods: This study included patients with LSS who relapsed following treatment with PELD therapy between March 2017 and March 2020. Visual analog scale (VAS) scores and Oswestry Disability Index (ODI) were analyzed preoperatively, postoperatively at 3, 6, 12, and 24 months, and at final follow-up. The modified MacNab criteria were used to assess clinical effects. All complications were recorded. Results: At a mean follow-up of 3 years, 24 patients with LSS who underwent repeat PELD were identified. The patients' mean operative time was 122.3±29.2 min, blood loss was 12.5±5.3 mL, and mean hospital stay was 7.0±1.9 days. VAS leg-pain score improved from 6.1±1.0 to 2.0±1.2 (P<0.001), VAS back-pain score improved from 6.2±0.8 to 2.1±1.1 (P<0.001), and ODI improved from 68.9±6.0 to 20.9±5.6 (P <0.001). According to the modified MacNab criteria, the good-to-excellent rate was 83.3%. Postoperative complications, including hematoma, nerve root injury, and dural injury, developed in four patients. Conclusion: Repeat PELD for reoperation in patients with LSS has a good clinical effect, and is recommended in routine clinical practice. Careful intraoperative manipulation is recommended to prevent complications.

Correlation Between Postoperative Imaging Parameters and Clinical Outcomes of Percutaneous Endoscopic Transforaminal Decompression for Lumbar Spinal Foraminal and Lateral Recess Stenosis.

Objective: To investigate the correlation between postoperative imaging parameters and clinical outcomes in patients with foraminal stenosis (FS) and lateral recess stenosis (LRS) who underwent percutaneous endoscopic transforaminal decompression (PETD). Methods: The study included 104 eligible patients who underwent PETD, and the mean follow-up time was 2.4 years (range 2.2-3.6 years). Visual Analog Scale (VAS) scores, Oswestry Disability Index (ODI) scores, and the modified MacNab criteria were used to evaluate the clinical outcomes. The related parameters of the FS and LRS based on computed tomography and magnetic resonance imaging were measured before and after surgery. Correlations between the imaging parameters and clinical outcomes were investigated. Results: The proportion of excellent and good results following MacNab evaluation was 82.6%. In the treatment of LRS, VAS-back, VAS-leg, and ODI at the 2-year follow-up were negatively correlated with postoperative facet joint length based on computed tomography. In the treatment of FS, the above clinical results were positively correlated with the variation of foraminal width and nerve root-facet distance before and after surgery based on magnetic resonance imaging. Conclusion: PETD can achieve good clinical outcomes in the treatment of patients with LRS or FS. Postoperative facet joint length was negatively correlated with clinical outcomes of LRS patients. In FS patients, the variation in foraminal width and nerve root-facet distance before and after surgery were positively correlated with their clinical outcomes. These findings may help surgeons optimize treatment strategies and selection of surgical candidates.

Paraspinal Muscle Degeneration: A Potential Risk Factor for New Vertebral Compression Fractures After Percutaneous Kyphoplasty.

Background: The paraspinal muscle is essential for maintaining normal spine function and structure, which degeneration is closely related to various spinal diseases. The main objective of this study was to identify the potential role of paraspinal muscle degeneration in the occurrence of new vertebral compression fractures (NVCF) and develop a clinically applicable nomogram for prospective NVCF risk prediction. Methods: A total of 202 patients with single-level osteoporotic vertebral compression fractures (OVCF) who underwent percutaneous kyphoplasty treatment between January 2016 and March 2019 were included in this study. Demographic, clinical, radiological, and treatment data were collected and analyzed. The paraspinal muscle cross-sectional area (CSA) and fat signal fraction (FSF) were measured to quantify the extent of muscle degeneration. Multivariate binary logistic regression analysis was performed to select risk factors to build a nomogram that predicted the occurrence of NVCF. The concordance index (C-index) and calibration curve were used to evaluate the discriminative capacity and predictive accuracy of the nomogram. Results: NVCF occurred in 54 of 202 patients (26.7%). The erector spinae FSF (OR = 1.064; P = 0.001), psoas major FSF (OR = 1.326; P < 0.001), and the difference index of the muscle CSA between multifidus and psoas major (OR = 1.048; P < 0.001) were independent risk factors for the occurrence of NVCF. The nomogram performance was good after evaluation using the calibration curves and C-index (95% confidence interval, 0.854-0.943). Conclusion: Paraspinal muscle degeneration is a potential risk factor for NVCF occurrence. A nomogram was designed to precisely predict the risk of NVCF. This predictive nomogram may help clinicians to make better clinical decisions and provide more accurate functional exercise protocol for OVCF patients.

Early Readmission and Reoperation After Percutaneous Transforaminal Endoscopic Decompression for Degenerative Lumbar Spinal Stenosis: Incidence and Risk Factors.

Purpose: To identify the incidence rates and risk factors for early readmission and reoperation after percutaneous transforaminal endoscopic decompression (PTED) for degenerative lumbar spinal stenosis (DLSS). Patients and Methods: A total of 1011 DLSS patients who underwent PTED were retrospectively evaluated. Of them, 58 were readmitted, and 31 underwent reoperation. The patients were matched with 174 control patients to perform case-control analyses. The clinical and preoperative imaging data of each patient were recorded. Univariate analyses were performed using independent sample t-tests and Fisher's exact tests. Furthermore, the risk factors for early readmission and reoperation were analyzed using multivariate logistic regression analyses. Results: The incidence rates of readmission and reoperation within 90 days after PTED were 5.7% and 3.1%, respectively. Age (odds ratio [OR]=1.054, p=0.001), BMI (OR=1.104, p=0.041), a history of lumbar surgery (OR=3.260, p=0.014), and the number of levels with radiological lumbar foraminal stenosis (LFS, OR=2.533, p<0.001) were independent risk factors for early readmission. The number of levels with radiological LFS (OR=5.049, p<0.001), the grade of surgical-level facet joint degeneration (OR=2.010, p=0.023), and a history of lumbar surgery (OR=10.091, p<0.001) were independent risk factors for early reoperation. Conclusion: This study confirmed that aging, a higher BMI, a history of lumbar surgery, and more levels with radiological LFS were associated with a higher risk of early readmission. More levels with radiological LFS, a higher grade of surgical-level facet joint degeneration, and a history of lumbar surgery were predictors of early reoperation. These results are helpful in patient counseling and perioperative evaluation of PTED.

Identification of preoperative radiological risk factors for reoperation following percutaneous endoscopic lumbar decompression to treat degenerative lumbar spinal stenosis.

Background: This study aimed to identify radiological risk factors associated with reoperation after percutaneous transforaminal endoscopic decompression (PTED) for degenerative lumbar spinal stenosis (DLSS). Methods: The preoperative clinical data of 527 consecutive patients with DLSS who underwent PTED were retrospectively reviewed. Overall, 44 patients who underwent reoperation were matched for age, sex, body mass index, and surgical segment to 132 control patients with excellent or good clinical outcomes. Radiological characteristics were compared between the groups using independent sample t-tests and Pearson's chi-square tests. A predictive model was established based on multivariate logistic regression analysis. Results: The analyses revealed significant differences in the presence of lumbosacral transitional vertebra (LSTV, 43.2% vs. 17.4%, p = 0.001), the number of levels with senior-grade disc degeneration (2.57 vs. 1.96, p = 0.018) and facet degeneration (1.91 vs. 1.25 p = 0.002), and the skeletal muscle index (SMI, 849.7 mm2/m2 vs. 1008.7 mm2/m2, p < 0.001) between patients in the reoperation and control groups. The results of the logistic analysis demonstrated that LSTV (odds ratio [OR] = 2.734, 95% confidence interval [CI]:1.222-6.117, p < 0.014), number of levels with senior-grade facet degeneration (OR = 1.622, 95% CI:1.137-2.315, p = 0.008), and SMI (OR = 0.997, 95% CI:0.995-0.999, p = 0.001) were associated with reoperation after PTED. The application of the nomogram based on these three factors showed good discrimination (area under the receiver operating characteristic curve 0.754, 95% CI 0.670-0.837) and good calibration. Conclusion: LSTV, more levels with senior-grade facet degeneration, and severe paraspinal muscle atrophy are independent risk factors for reoperation after PTED. These factors can thus be used to predict reoperation risk and to help tailor treatment plans for patients with DLSS.

Posterior Apophyseal Ring Fracture in Adult Lumbar Disc Herniation: An 8-Year Experience in Minimally Invasive Surgical Management of 48 Cases.

OBJECTIVE: Posterior apophyseal ring fracture (PARF) is an uncommon disorder that is usually accompanied by lumbar disc herniation (LDH). The aim of this study to describe the 8-year experience of performing minimally invasive treatment of PARF, giving particular attention to surgical technique and clinical outcome. METHODS: We reviewed 1,324 consecutive patients with LDH seen in our department between 2013 and 2020. Forty-eight patients (3.63%) were enrolled who were diagnosed with PARF associated with LDH and underwent transforminal endoscopic lumbar discectomy (TELD). Mean duration of the final postoperative follow-up was 5.1 years. The control group was comprised of 50 patients diagnosed with LDH without PARF at the same facility. Data on clinical outcomes were analyzed. RESULTS: The mean operation time in the PARF group was 105.4 minutes, which was longer than the mean operation time of the control group (83.9 minutes) (p = 0.001). Surgical complications, including dural tears (6.3%) and surgical instrument rupture (4.2%) were more common in the PARF group (p = 0.025). However, there was no significant difference in the proportion of excellent and good results and recurrence rates between the LDH patients with and those without PARF, respectively. CONCLUSION: TELD is a safe and effective minimally invasive approach for the treatment of PARF. However, minimally invasive techniques may require longer operation time and steeper learning curve for inexperienced surgeons. The separation and removal of bone fragments, a key step in the procedure, requires patience and care to prevent rupture, residual surgical instruments, and leakage of cerebrospinal fluid.

A predictive nomogram for intradiscal cement leakage in percutaneous kyphoplasty for osteoporotic vertebral compression fractures combined with intravertebral cleft.

Background: For patients with osteoporotic vertebral compression fractures (OVCFs) treated with percutaneous kyphoplasty (PKP), the occurrence and risk factors of intradiscal cement leakage should be characteristic of the presence of intravertebral cleft (IVC). This study aimed to identify risk factors for intradiscal leakage in individuals with OVCFs combined with IVC treated with PKP and build a powered and well-calibrated predictive nomogram. Methods: This study retrospectively reviewed consecutive patients who underwent PKP at our center between January 2016 and May 2021. Patients diagnosed with OVCFs combined with IVC were identified, and the incidence of different types of bone cement leakage was recorded. Risk factors for intradiscal leakage among the demographic, perioperative baseline, and radiologic data were identified, following which a nomogram was developed and verified. Results: A total of 109 eligible patients were included, and the intradiscal leakage rate was 32.1%. Compression rate (odds ratio [OR] 0.025; 95% confidence interval [CI] 0.002-0.264; P = 0.002) and cemented vertebral body fraction (OR 44.122; 95% CI 2.790-697.740; P = 0.007) were identified as independent risk factors. A predictive nomogram with good predictive power (C-statistic = 0.786) and fitness of data (Hosmer-Lemeshow goodness-of-fit test, P = 0.092) was established to build a quantitative relationship between the risk factors and intradiscal leakage. Conclusion: The incidence rate of intradiscal leakage in PKP for OVCFs combined with IVC was 32.1%. Compression rate and cemented vertebral body fraction were identified as independent risk factors. A powered and well-calibrated nomogram was established to accurately predict the probability of intradiscal leakage. Further prospective and multicenter studies are required to verify and calibrate our findings.

Cervical Extensor Muscles Play the Role on Malalignment of Cervical Spine: A Case Control Study With Surface Electromyography Assessment.

STUDY DESIGN: A case control study. OBJECTIVE: The aim of this study was to identify the potential impact of cervical spine malalignment on muscle parameters. SUMMARY OF BACKGROUND DATA: Muscular factors are associated with cervical alignment. Nevertheless, only muscle dimensions or imaging changes have been evaluated, function of cervical muscles has scarcely been investigated. METHODS: Thirty-four patients diagnosed as cervical spine degeneration associated with cervical malalignment and 32 control subjects were included in this case control study. Visual analogue scale (VAS) and the neck disability index (NDI) were used. The sagittal alignment parameters and cervical range of motion (ROM) were measured on cervical spine lateral radiographs, included C2-C7 lordosis, C2-C7 sagittal vertical axis (C2-C7 SVA), cervical gravity-sagittal vertical axis (CG-SVA), T1-Slope, and spinal canal angle (SCA). Surface electromyography (SEMG)-based flexion-relaxation ratio (FRR) was measured. RESULTS: The result showed VAS score of the neck significantly lower in controls (P<0.05), C2-C7 lordosis, C2-C7 SVA, CG-SVA, T1-Slope and ROM showed significantly different (P<0.001) between malalignment group and control group, FRR of splenius capitis (FRRSpl) and upper trapezius (FRRUTr) of the malalignment group were lower than in the control group, which correlated well with NDI (rSpl = -0.181 rUTr = -0.275), FRRSpl correlated well with VAS (rSpl = -0.177). FRRSpl correlated strongly with C2-C7 SVA (r = 0.30), CG-SVA (r = 0.32), T1-Slope (r = 0.17), ROM (r = 0.19), FRRUTr correlated with C2-C7 lordosis (r = -0.23), CG-SVA (r = 0.19), T1-Slope (r = 0.28), ROM (r = 0.23). CONCLUSION: Cervical malalignment patients had more tensional posterior cervical muscle and poor muscle functions. CG-SVA showed advantages in evaluating cervical malalignment.Level of Evidence: 3.

Can knee flexion contracture affect cervical alignment and neck tension? A prospective self-controlled pilot study.

BACKGROUND CONTEXT: The coordination of the alignment between the lower extremities and cervical spine helps to achieve balance and horizontal gaze during standing and walking. Malalignment in any segment can disturb the global balance, causing compensation in another segment. Knee flexion contracture (KFC) can cause spine inclination with increased C7 tilt or C7 SVA (sagittal vertical axis). Cervical alignment and the posterior muscles are essential for maintaining the horizontal gaze which is closely related to neck tension (NT). PURPOSE: This study aimed to determine whether KFC can affect cervical alignment and its potential effects on the posterior muscles and NT. DESIGN: A prospective pilot study was carried out in preoperative (pre-op) and postoperative (post-op) phases. PATIENT SAMPLE: This study included 22 consecutive patients with KFC and 12 control subjects in our department who agreed to participate from between August 1, 2018 and February 28, 2019 in our department. OUTCOME MEASURES: Visual analog scale (VAS) and neck disability index (NDI) were used. The sagittal alignment parameters and cervical range of motion (ROM) were measured on radiographic images, and included the C0-C2 lordosis (C0-2L), C2-C7 lordosis (C2-7L), C2 SVA, C7 SVA, T1 slope, thoracic kyphosis, lumbar lordosis (LL), pelvic tilt, sacral slope, and knee flexion angle (KA). Surface electromyography-based flexion-relaxation ratio (FRR) and ultrasound-based shear wave elastography (SWE) were performed. METHODS: The control group was matched for age, sex, and body mass index with the KFC group. Patients in the KFC group underwent arthroscopic surgery to correct knee alignment. Comparisons between pre-op and post-op phases were performed using paired sample t tests, comparisons between KFC and control groups were performed using independent samples t tests. The correlation analysis between the parameters was performed using Spearman analysis. Funding for this study was provided by the National Natural Science Foundation of China (60,000 USD), Beijing Municipal Administration of Hospitals Incubating Program (50,000 USD), and Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support (20,000 USD). There were no conflicts of interest associated with this study. RESULTS: The average follow-up time for this pilot study was 11.4±1.5 days. Pre-op, the KFC group had higher KA, T1S, C7 SVA, C2 SVA, C0-2L, SWE, VAS, and NDI compared with the control group, but all of these parameters were decreased significantly post-op. The LL, FRR of splenius capitis (FRRsc), and ROM of the KFC group pre-op were lower than the control group, and all of these were increased significantly post-op. There were no differences in pelvic tilt, sacral slope, C2-7 L, or TK between the KFC and control groups, or in FRR of splenius capitis (FRRutr) between pre-op and post-op phases. KA had strong correlations with LL (r=-0.83), which correlated well with C7 SVA (r=-0.75). C7 SVA correlated strongly with C2 SVA (r=0.79), which also correlated strongly with C0-2 L (r=0.76). C0-2 L correlated well with FRRsc (r=-0.65) and SWEsc (r=0.72), and both of them correlated well with VAS (r=-0.54, r=0.71) and NDI (r=-0.57, r=0.76). ROM correlated well with FRRsc (r=0.71), SWEsc (r=-0.74), VAS (r=-0.66), and NDI (r=-0.66). CONCLUSIONS: KFC may cause spine inclination and craniocervical malalignment, leading to NT and ROM reduction. The results of this pilot study may be helpful in guiding further studies concerning KFC and NT.