Search

Background Lateral lumbar interbody fusion (LLIF) is widely used in degenerative lumbar spine surgery. Previous studies of radiographic investigations after LLIF have assessed the anterior interbody fusion rate, the changes in the segmental lumbar lordosis, efficacy of indirect neural decompression, and remodeling of the ligamentum flavum hypertrophy and spinal canal dimension, and so on. The purpose of this study was to evaluate the radiological changes in the degenerated facet joints following LLIF with bilateral percutaneous pedicle screw (PPS) fixation, focusing on spontaneous fusion. Methods We retrospectively analyzed 31 patients (79 surgical levels) who underwent two- or three-level LLIF with PPS fixation without direct posterior decompression and bone grafting. We assessed the fusion rate and characteristics of the facet joints’ fusion process on the preoperative, immediately postoperative, 12-month, and at least 2-year computed tomography (CT) images. On average, the last follow-up CT was performed after 30.2 months. Multivariate logistic regression analysis investigated factors related to spontaneous facet joint fusion postoperatively. Results The fusion rates of the interbody and facet joints were 32.9% (26/79) and 19.0% (15/79) after 12-months and 79.7% (63/79) and 58.2% (46/79) at the final CT follow-up, respectively. Of the 46 cases with spontaneous facet fusion, three cases fused posteriorly only. Concomitant anterior interbody fusion was seen in 43/46 (93.5%) cases. Facet fusion started in a ring shape from the outermost joint edges, exposing subchondral bone without cartilage covering, and progressed to the central thicker cartilage regions. Multivariate analysis established that concomitant anterior interbody fusion (adjusted odds ratio [aOR]: 12.10, P = 0.0035) and preoperative facet joint osteoarthritis of Weishaupt Grade ≧ 1 (aOR: 4.770, P = 0.0068) were significant contributing factors to postoperative spontaneous facet fusion. Conclusions Our study shows that spontaneous facet fusion frequently occurs after LLIF and may be an indicator of the inherent structural stability of the LLIF construct.

To determine the incidence and worsening of lumbar spine structure and low back pain (LBP) and whether they are predicted by demographic characteristics or clinical characteristics or appendicular joint osteoarthritis (OA).Paired baseline (2003-2004) and follow-up (2006-2010) lumbar spine radiographs from the Johnston County Osteoarthritis Project were graded for osteophytes (OST), disc space narrowing (DSN), spondylolisthesis, and presence of facet joint OA (FOA). Spine OA was defined as at least mild OST and mild DSN at the same level for any level of the lumbar spine. LBP, comorbidities, and back injury were self-reported. Weibull models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) of spine phenotypes accounting for potential predictors including demographic characteristics, clinical characteristics, comorbidities, obesity, and appendicular OA.Obesity was a consistent and strong predictor of incidence of DSN (HR 1.80 [95% CI 1.09-2.98]), spine OA (HR 1.56 [95% CI 1.01-2.41]), FOA (HR 4.99 [95% CI 1.46-17.10]), spondylolisthesis (HR 1.87 [95% CI 1.02-3.43]), and LBP (HR 1.75 [95% CI 1.19-2.56]), and worsening of DSN (HR 1.51 [95% CI 1.09-2.09]) and LBP (HR 1.51 [95% CI 1.12-2.06]). Knee OA was a predictor of incident FOA (HR 4.18 [95% CI 1.44-12.2]). Spine OA (HR 1.80 [95% CI 1.24-2.63]) and OST (HR 1.85 [95% CI 1.02-3.36]) were predictors of incidence of LBP. Hip OA (HR 1.39 [95% CI 1.04-1.85]) and OST (HR 1.58 [95% CI 1.00-2.49]) were predictors of LBP worsening.Among the multiple predictors of spine phenotypes, obesity was a common predictor for both incidence and worsening of lumbar spine degeneration and LBP.

BACKGROUND: The finite element method (FEM) is an efficient and powerful tool for studying human spine biomechanics. OBJECTIVE: In this study, a detailed asymmetric three-dimensional (3D) finite element (FE) model of the upper cervical spine was developed from the computed tomography (CT) scan data to analyze the effect of ligaments and facet joints on the stability of the upper cervical spine. METHODS: A 3D FE model was validated against data obtained from previously published works, which were performed in vitro and FE analysis of vertebrae under three types of loads, i.e. flexion/extension, axial rotation, and lateral bending. RESULTS: The results show that the range of motion of segment C1–C2 is more flexible than that of segment C2–C3. Moreover, the results from the FE model were used to compute stresses on the ligaments and facet joints of the upper cervical spine during physiological moments. CONCLUSION: The anterior longitudinal ligaments (ALL) and interspinous ligaments (ISL) are found to be the most active ligaments, and the maximum stress distribution is appear on the vertebra C3 superior facet surface under both extension and flexion moments.

Background: Lumbar facet joint is an important element of spinal “three-joint complex”. Whether there is a relationship between strange structure of facet joint and adolescent lumbar disc herniation (ALDH) is nonetheless controversial, and the current research is mainly centered on adults. Objective: To find out the normal lumbar facet joints between 13 and 18 years old to provide anatomical basis for early diagnosis and therapy of lumbar disc herniation. Methods: CT imaging information of 32 sufferers with lumbar disc herniation aged from 13 to 18 years old in Inner Mongolia have been collected as the ALDH group, and 62 wholesome subjects in the equal period had been chosen as the normal group. Uncooked records of continuous scanning lumbar tomography pix were imported into MIMICS 21.0 for evaluation and size in DICOM format. The parameters include facet joint height, facet joint width, et al. Results: 1. The left and right transverse angle of L5S1 segment in the ALDH group were (52.41 ± 9.2) ° and (55.99 ± 10.91) ° (P

Facet joints are the important articular pillars of the spine. Several pathologies can occur in and around the facet joint, including extra ossicles, traumatic dislocation, osteoarthritis, synovial cyst, axial spondyloarthritis, rheumatoid arthritis, calcium pyrophosphate deposition disease, septic arthritis, and malignant and benign neoplasms. Imaging is the mainstay to detect and characterize these diseases. In this review, we discuss the anatomy and function of facet joints, imaging techniques, and the imaging findings of several facet joint diseases. This information may be helpful to radiologists to make the correct diagnosis and optimize the management of patients with facet joint diseases.

Purpose Adjacent segment disease (ASD) requiring revision surgery is the most serious complication that can occur in patients undergoing posterior lumbar interbody fusion (PLIF) surgery. This study aimed to determine the risk factors for surgical ASD requiring revision surgery after PLIF with screw fixation surgery. We especially focused on paraspinal muscle, facet joint, and disc degeneration. Methods Among the patients who underwent PLIF with screw fixation due to degenerative spinal disease from January 2010 to December 2019, patients who underwent revision surgery for the development of ASD were enrolled. To evaluate the risk factors for surgical ASD, we selected a control group. Each patient in the control group was matched by age, sex, fusion level, number of fused segments, secondary MRI follow-up interval, and follow-up duration with a patient in the surgical ASD group. The radiographic and demographic data were compared between the surgical ASD and control groups. Results There were statistically significant differences between the two groups in radiological parameters of preoperative facet degeneration, facet effusion, facet angle, and fatty degeneration of the multifidus muscle. Multivariable logistic regression analysis revealed that preoperative facet effusion (odds ratio [OR] 6.48), preoperative facet angle (OR 1.24), and progression of fatty degeneration in the multifidus muscle (OR 1.07) were significant risk factors for surgical ASD. Conclusions Preexisting high-grade adjacent facet effusion, sagittally oriented facet joint angle, and progressive fatty degeneration of the multifidus muscle are associated with the development of surgical ASD after PLIF surgery.

Background Compression-extension injury with unilateral facet joint fracture is one of the most devastating injuries of subaxial cervical spine. However, it is not yet clear which fixation technique represents the optimal choice in surgical management. This study aims to assess the construct stability at the operative level (C4/C5 cervical spine) following anterior cervical discectomy and fusion (ACDF) alone and combined fixation techniques (posterior-anterior fixations). Methods A previously validated three-dimensional C2-T1 finite element model were modified to simulate surgical procedures via the anterior-only approach (ACDF) and combined cervical approach [(transarticular screw, lateral mass screw, unilateral pedicle screw, bilateral pedicle screw) + ACDF, respectively] for treating compression-extension injury with unilateral facet joint fracture at C4/C5 level. Construct stability (range of rotation, axial compression displacement and anterior shear displacement) at the operative level was comparatively analyzed. Results In comparison with combined fixation techniques, a wider range of motion and a higher maximum von Mises stress was found in single ACDF. There was no obvious difference in range of motion among transarticular screw and other posterior fixations in the presence of anterior fixation. In addition, the screws inserted by transarticular screw technique had high stress concentration at the middle part of the screw but much less than 500 MPa under different conditions. Furthermore, the variability of von Mises stress in the transarticular screw fixation device was significantly lower than ACDF but no obvious difference compared with other posterior fixations. Conclusions Of the five fixation techniques, ACDF has proven poor stability and high structural stress. Compared with lateral and pedicle screw, transarticular screw technique was not worse biomechanically and less technically demanding to acquire in clinical practice. Therefore, our study suggested that combined fixation technique (transarticular screw + ACDF) would be a reasonable treatment option to acquire an immediate stabilization in the management of compression-extension injury with unilateral facet joint fracture. However, clinical aspects must also be regarded when choosing a reconstruction method for a specific patient.

Background Previous studies have shown a wide range of anatomical classifications of the subtalar joint (STJ) in the population and this is related to the different force line structures of the foot. Different subtalar articular surface morphology may affect the occurrence and development of flat foot deformity, and there are fewer studies in this area. The main objective of our study was to determine the association of different subtalar articular surface with the occurrence and severity of flat foot deformity. Methods We analyzed the imaging data of 289 cases of STJ. The articular surface area, Gissane’s angle and Bohler’s angle of subtalar articular surface of different types were counted. The occurrence and severity of flat foot deformity in different subtalar articular surface were judged by measuring the Meary angle of foot. Results We classified 289 cases of subtalar articular surface into five types according to the morphology. According to Meary angle, the flat foot deformity of Type I and Type IV are significantly severer than Type II (P ). Type II (7.65 ± 1.38 cm2) was significantly smaller than Type I (8.40 ± 1.79 cm2) in the total joint facet area(P ). Type III (9.15 ± 1.92 cm2) was smaller than Type I (8.40 ± 1.79 cm2), II (7.65 ± 1.38 cm2) and IV (7.81 ± 1.74 cm2) (P ). Type II (28.81 ± 7.44∘) was significantly smaller than Type I (30.80 ± 4.61 degrees), and IV (32.25 ± 5.02 degrees) in the Bohler’s angle (P ). Type II (128.49 ± 6.74 degrees) was smaller than Type I (131.58 ± 7.32 degrees), and IV (131.94 ± 5.80 degrees) in the Gissane’s angle (P ). Conclusions After being compared and analyzed the measurement of morphological parameters, joint facet area and fusion of subtalar articular surface were closely related to the severity of flat foot deformity and Type I and IV were more likely to develop severer flat foot deformity. Level of evidence Level III, retrospective comparative study.

Background Various surgical techniques have been described to address intraforaminal/extraforaminal lumbar lesions. They vary from the classic posterior open approaches to minimally invasive techniques with tubular retractors and even endoscopy. These lesions have been approached from either an ipsilateral or a contralateral approach. Only a few reports have described a contralateral minimally invasive tubular approach to address these lesions. However, none of them have been able to address calcified pathologies. Method We used a contralateral tubular approach to remove the calcified disc herniations in 2 patients presenting with radiculopathy secondary to a calcified intraforaminal L5-S1 disc herniation. Results Early clinical and radiological outcomes were positive. No perioperative complications occurred. Conclusions To our knowledge, this is the first report of the expanded use of fixed tubular retractors to address calcified lumbar intraforaminal disc herniations. This approach allows a satisfactory access and view of the contralateral foramen and offending lesion. It permits a wide decompression while preserving the facet joint and thus prevents iatrogenic instability. It can also avoid the iliac crest, which does not allow an ipsilateral extraforaminal approach at the L5-S1 level. This approach is a safe and effective way to treat this specific pathology.

Study design Retrospective longitudinal cohort study. Objective To investigate the impact of facet joint opening (FJO) on clinical outcomes after minimally invasive decompression surgery for lumbar spinal stenosis. Summary of background data Although FJOs have previously been identified as indicators of segmental spinal instability, their impact on clinical outcomes after decompression alone surgery has yet to be investigated. Methods This study included 296 patients from a single institution who underwent minimally invasive surgery for lumbar spinal stenosis and were followed up for ≥5 years. Our analysis focused on identifying FJOs at the index decompression level (d-FJO) and at multiple levels (m-FJO) (i.e., ≥3 levels within the lumbar segment) using preoperative computed tomography. Clinical outcomes including reoperations, improvement ratio for Japanese Orthopaedic Association (JOA) score, and achievement of a minimal clinically important difference (MCID) in visual analogue scale (VAS) scores for low back pain (LBP) or leg pain at 5 years were compared between patients with and without d-FJO or m-FJO. Results There were 129 (44%) and 62 (21%) patients with d-FJO (more common with lateral olisthesis) and m-FJO (less common with spondylolisthesis), respectively. Reoperations were more common in patients with d-FJO than in those without (16% vs. 5%). On Cox proportional hazards analysis, d-FJO was identified as a predictor for revision at the index decompression level [hazard ratio (HR) 4.04, p = 0.03], whereas m-FJO was a predictor for revision at other lumbar levels (HR 3.71, p = 0.03). Patients with m-FJO had slightly lower rates of achieving MCID in VAS scores for LBP (34% vs. 52%, p = 0.03) and poorer improvement ratio forJOA scores (74% vs. 80%, p = 0.03) than those without. Conclusion FJO at both index decompression level and multiple level were predictors of poor outcomes; patients with FJOs require careful surgical planning or special follow-up.Level of Evidence: 3.

Objectives To investigate the occurrence of facet joint ankylosis in the spine of patients with radiographic axial spondyloarthritis (r-axSpA) using low dose computed tomography (ldCT), and to examine the association between facet joint ankylosis and functional impairment. Methods A group of 126 patients with r-axSpA was selected from Incheon Saint Mary's axSpA observational cohort and whole spine ldCT data were examined. Facet joint (right and left, C2–S1) ankylosis was scored from 0–46 (total). The presence of facet joint ankylosis was assessed by two readers, each blinded to the patient data. The inter-reader reliability of facet joint ankylosis scoring was assessed using intraclass correlation coefficients (ICCs). The CT Syndesmophyte Score (CTSS) was assessed. Lumbar spinal mobility was evaluated using the modified Schober test. Functional impairment was measured using the Bath AS functional index (BASFI). Results The ICCs of ankylosed facet joint scores at the cervical, thoracic, lumbar and whole spine were 0.84, 0.88, 0.92 and 0.90, respectively. Facet joint ankylosis was most common in the thoracic spine. Scores for the whole spine correlated positively with the ASDAS, mSASSS and the syndesmophyte score. Multivariate analysis revealed that facet joint ankylosis was significantly associated with decreased lumbar motion. For both readers, the scores for the whole spine were independently associated with BASFI after adjusting for syndesmophyte score and disease activity. Conclusions Facet joint ankylosis in patients with r-axSpA was associated with functional impairment and spinal mobility. Facet joints should be incorporated into a structural damage assessment method.

Background In interventional pain medicine, cervical facet joint (CFJ) pain is commonly treated with CFJ denervation techniques, almost automatically assuming degeneration of the CFJs as an important cause of CFJ pain. A standard cervical X‐ray is still commonly used in the clinical evaluation of patients suspected for CFJ degeneration. Although degenerative features can be visualized by different radiological imaging techniques, the relation between radiological degenerative features of the cervical spine and pain remains controversial. Paramount in order to estimate the clinical usefulness of a radiological imaging is to establish the reproducibility of the radiological scoring system. A reproducible and clinically feasible diagnostic scoring system was developed to estimate cervical degeneration on standard cervical X‐rays. Materials and Methods A reproducibility study for the interpretation of degenerative abnormalities on standard cervical X‐rays was performed, using a dichotomous outcome (degenerative abnormalities present Yes/No). The estimation of intervertebral disc height loss on standard cervical X‐rays was validated with computed tomography (CT) scan measurements. Results Five radiological degenerative features on standard cervical X‐rays (disc height loss, anterior vertebral osteophytes, posterior vertebral osteophytes, vertebral end plate sclerosis, and uncovertebral osteoarthritis) showed a substantial to excellent reproducibility (kappa value ≥ 0.60). The qualitative definition of disc height loss used in the reproducibility study showed a substantial agreement with the actual measurements of disc height loss on CT scan (kappa value = 0.69). Conclusion Subjective judgment of a cervical standard X‐ray is a reproducible method to demonstrate degenerative abnormalities of the cervical spine.

Background We describe the minimally invasive, facet-sparing postero-lateral approach to the thoracic spine for a ventral dural repair in a patient with intracranial hypotension secondary to a spontaneous dural breach. Methods We performed a minimally invasive approach using a short paramedian posterior skin incision followed by a 10 × 10 mm targeted trans-laminar approach, to achieve a microsurgical repair of a symptomatic ventral dural defect causing severe disability. Conclusion The facet-sparing postero-lateral approach is safe and effective in the surgical management of thoracic dural tears, even in the most anterior ones, and avoids the traditional costotransversectomy.

Objective Lumbar interventional pain procedures (LIPPs) are frequently used in low back pain and have shown an increasing trend in recent years. LIPPs are highly effective when performed by properly trained physicians. However, some adverse events are seen during interventional procedures. Our aim in this study is to determine the immediate adverse event rates of LIPPs and to inform our colleagues about possible adverse events. Study Design Retrospective, observational study. Setting A university hospital pain management center. Methods After approval by the institutional ethics committee, a retrospective evaluation of patients who received fluoroscopy-guided LIPPs between January 2015 and December 2020 was performed. This observational study was conducted with 4,209 patients who underwent LIPPs, including epidural steroid injection, sacroiliac and facet joint injection, medial branch block or radiofrequency ablation, application of pulsed radiofrequency to the dorsal root ganglion, epidural catheter placement, or spinal cord stimulator application. Results No major adverse events were detected during the procedures. Minor adverse events were detected in 60 patients, and the adverse events rate was found to be 1.4% (95% confidence interval: 1.0–1.8%). Minor adverse events rates varied between 0.7% and 2.3% according to the procedure type. The most common adverse events were determined to be vasovagal reactions (26/60). Facial numbness, cramps, and seizures were detected as rare adverse events. Conclusion No major adverse events were seen in 4,209 patients. The rate of minor adverse events was 1.4%, with no sequelae in any of the events. When evidence-based guidelines are followed, interventional pain procedures can be performed safely.

Background An incidental dural tear is a well-known complication during spine surgery. A rare consequence is a postoperative nerve root herniation. The purpose of this report is to describe a case of such a herniation with entrapment in the facet gap joint and to present the first MR images of this rare surgical complication. Case presentation We report a case of a patient who underwent lumbar decompression surgery and afterwards suffered a sudden intractable sciatica. Postoperative MRI showed a new facet joint gap effusion. During revision surgery an entrapped nerve root was found in the facet joint gap. In retrospective, the herniated nerve root is visible on postoperative MRI. Conclusion This case report highlights a rare complication during spine surgery. This finding is important as signs suggestive for nerve root herniation can easily be overlooked on MRI. Furthermore, this represents the first MRI documentation of this complication.

An understanding of the common MRI findings observed after decompression surgery is important. However, to date, no study addressing this has been published. The aim of this study was to analyze and describe the immediate postoperative MRI findings after lumbar decompression surgery. We retrospectively analyzed the immediate postoperative MRIs of 121 consecutive patients who underwent lumbar decompression surgery between July 2017 and June 2018. Changes in stenosis at the decompressed and adjacent levels, epidural fat edema, epidural and subdural fluid collections, nerve root swelling, facet joint effusions, intervertebral disc signal, and paravertebral muscle edema were correlated with clinical characteristics. Both groups had reduced central canal stenosis postoperatively (p 0.001) but worsened stenosis at adjacent segments. Fluid collection, hemorrhagic or non-hemorrhagic, at the laminectomy site was the commonest finding (one-level: 73.8%, two-level: 88.5%), with a higher percentage of severe central canal compromise in the two-level decompression group (p = 0.003). Other postoperative MRI findings, such as epidural fat edema, nerve root swelling, subdural fluid collection, and facet joint effusion, were noted without statistical significance. In conclusion, even with successful decompression for lumbar canal stenosis, increased central canal stenosis at adjacent segments is common on immediate postoperative MRI scans, showing no statistically significant correlation with the immediate postoperative outcome. Postoperative fluid collection at the laminectomy site is the commonest imaging finding, and higher rates of hemorrhagic fluid and more severe central canal compromise occur in two-level decompression, but rarely cause clinical problems.

To analyze the clinical and biomechanical outcome of professional athletes after lumbar total disk replacement, with a focus on restoration of the functional activity.This nonrandomized retrospective single-center study included 11 professional athletes who underwent lumbar disc replacement surgery using the prosthesis M6-L (Spinal Kinetics, Schaffhausen, Switzerland). The average postoperative follow-up was 3.18 ± 1.14 years. The following outcomes were evaluated: intensity of pain in the lumbar spine and lower limbs, Oswestry Disability Index, Short-Form 36, complications, time of return to previous sports activity, range of movement, degree of lumbar lordosis, degenerative changes of the adjacent levels, and degree of heterotopic ossification.The operated patients reported significant decrease of pain on visual analog scale (P0.001) as well as significant improvement of Oswestry Disability Index (P = 0.001) and Short-Form 36 (P0.001). For the duration of follow-up, the patients maintained segmental range of motion at L4-L5 (P = 0.04) and L5-S1 (P = 0.03) levels. There was also some statistically insignificant increase of global lumbar lordosis (P = 0.84). We did not identify any significant degeneration of the adjacent intervertebral disks (P0.05) or progression of the facet joint degenerative changes at the implantation level and in the adjacent segments (P0.05). One patient (9.1%) developed grade I heterotopic ossification 5 years after surgery and in 1 patient (9.1%), a lesion of superior hypogastric plexus was recorded. The average time of return to previous sports activity was 9.72 ± 3.03 weeks.Total lumbar disc replacement using M6-L prosthesis in professional athletes made it possible to achieve statistically significant reduction of pain and facilitated early return to normal sports activities. In our opinion, preservation of movement of the operated lumbar segment can help to reduce the mechanical stress with beneficial impact on the rate of degeneration of the adjacent level.

Objective To directly compare robotic-versus fluoroscopy-guided percutaneous pedicle screw (PPS) placement in thoracolumbar spine trauma with a focus on clinically acceptable pedicle screw accuracy and facet joint violation (FJV). Methods A retrospective chart review assessed 37 trauma patients undergoing percutaneous thoracic and/or lumbar fixation. Postoperative computed tomography images were reviewed by authors blinded to surgical technique who assessed pedicle screw trajectory accuracy and FJV frequency. Results Seventeen patients underwent placement of 143 PPS with robotic assistance (robot group), compared with 20 patients receiving 149 PPS using fluoroscopy assistance (control group). Overall, the robot cohort demonstrated decreased FJV frequency of 2.8% versus 14.8% in controls (P = 0.0003). When further stratified by level of surgery (i.e., upper thoracic, lower thoracic, lumbar spine), the robot group had FJV frequencies of 0%, 3.2%, and 3.7%, respectively, compared with 17.7% (P = 0.0209), 14.3% (P = 0.0455), and 11.9% (P = 0.2340) in controls. The robot group had 84.6% clinically acceptable screw trajectories compared with 81.9% in controls (P = 0.6388). Within the upper thoracic, lower thoracic, and lumbar regions, the robot group had acceptable screw trajectories of 66.7%, 87.1%, and 90.7%, respectively, compared with 58.8% (P = 0.6261), 91.1% (P = 0.5655), and 97.6% (P = 0.2263) in controls. Conclusions There was no significant difference in clinically acceptable screw trajectory accuracy between robotic versus fluoroscopy-guided PPS placement. However, the robot cohort demonstrated a statistically significantly decreased FJV overall and specifically within the thoracic spine region. Use of robotic technology may improve radiographic outcomes for a subset of patients or spine surgeries.

One-in-five people suffer from chronic low back pain (LBP). The incidence of this disease has doubled since 1950s and affects not only the elderly, but also the young population. However, the mechanism of LBP is still unknown. A possible location where the LBP may develop is the facet joint and it has been revealed that the intervertebral disc (IVD) nucleotomy may be a trigger for LBP. The aim of the present study was to investigate the influence of IVD nucleotomy on the load sharing in the spinal facet joint under the loading scenarios of different postures. Finite element (FE) models of the intact and nucleotomised L4 – L5 spinal segments were generated from the clinical CT images. Seven human postures, including upright, 5° extension, 5° flexion, ± 6° lateral bending and ± 2° axial rotation, were simulated. The resultant forces in the fact joint were compared between the intact and the nucleotomised cases. It was revealed that the IVD nucleotomy significantly increased the forces in the facet joints under the loading scenarios of upright, 5° extension and 5° flexion. The IVD nucleotomy increased the force in the ipsilateral facet joint but decreased the force on the contralateral side under the loading scenarios of ± 2° axial rotation. However, the IVD nucleotomy made little influence on the resultant forces in both facet joints in the postures of ± 6° lateral bending. In conclusion, the IVD nucleotomy can cause an increase in the overall force in the facet joint, and thus may serve as a possible explanation for the LBP and a main contributing factor for the pain complaints.

Objective Pathology of the facet and sacroiliac (SI) joints contributes to 15% to 45% and 10% to 27% of lower back pain cases, respectively. Although tissue engineering may offer novel treatment options to patients suffering from cartilage degeneration in these joints, the tribological characteristics of the facet and SI joints have not been studied in either the human or relevant large animal models, which hinders the development of joint-specific cartilage implants. Design Cartilage was isolated from the knee, cervical facet, thoracic facet, lumbar facet, and SI joints of 6 skeletally mature Yucatan minipigs ( Sus scrofa). Tribological characteristics were assessed via coefficient of friction testing, interferometry, and immunohistochemistry for lubricin organization. Results Compared with the knee, the coefficient of friction was higher by 43% in the cervical facet, 77% in the thoracic facet, 37% in the lumbar facet, and 28% in the SI joint. Likewise, topographical features of the facet and SI joints varied significantly, ranging from a 114% to 384% increase and a 48% to 107% increase in global and local surface roughness measures, respectively, compared with the knee. Additionally, the amount of lubricin in the SI joint was substantially greater than in the knee. Statistical correlations among the various tribological parameters revealed that there was a significant correlation between local roughness and coefficient of friction, but not global roughness or the presence of lubricin. Conclusion These location-specific tribological characteristics of the articular cartilages of the spine will need to be taken into consideration during the development of physiologically relevant, functional, and durable tissue-engineered replacements for these joints.

Background The superior facet arthroplasty is important for intervertebral foramen microscopy. To our knowledge, there is no study about the postoperative biomechanics of adjacent L4/L5 segments after different methods of S1 superior facet arthroplasty. To evaluate the effect of S1 superior facet arthroplasty on lumbar range of motion and disc stress of adjacent segment (L4/L5) under the intervertebral foraminoplasty. Methods Eight finite element models (FEMs) of lumbosacral vertebrae (L4/S) had been established and validated. The S1 superior facet arthroplasty was simulated with different methods. Then, the models were imported into Nastran software after optimization; 500 N preload was imposed on the L4 superior endplate, and 10 N⋅m was given to simulate flexion, extension, lateral flexion and rotation. The range of motion (ROM) and intervertebral disc stress of the L4-L5 spine were recorded. Results The ROM and disc stress of L4/L5 increased with the increasing of the proportions of S1 superior facet arthroplasty. Compared with the normal model, the ROM of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 2/5 from the apex to the base. The disc stress of L4/L5 significantly increased in most directions of motion when S1 superior facet formed greater than 3/5 from the ventral to the dorsal or 1/5 from the apex to the base. Conclusion In this study, the ROM and disc stress of L4/L5 were affected by the unilateral S1 superior facet arthroplasty. It is suggested that the forming range from the ventral to the dorsal should be less than 3/5 of the S1 upper facet joint. It is not recommended to form from apex to base. Level of evidence Level IV

Objective The objective of this study was to establish the level of inter-examiner reliability for six common cervical manual and physical examination procedures used to assess the cervical spine. Materials: Reliability study that used a convenience sample of 51 patients between the ages of 16–70 years presenting with a chief complaint of neck pain. Two physical therapists independently performed the same series of cervical physical examination procedures on each of the participant. The clinicians were blinded to each other’s findings and the clinical status of the patient. Kappa coefficients (κ) were calculated for levels of agreement between the clinicians for each procedure. Results When assessing for asymmetrical motion, excellent levels of reliability (κ range: 0.88–0.96) were observed for the Bilateral Modified Lateral Shear (asymmetry criterion), Bilateral C2 Spinous Kick (asymmetry criterion) and Flexion-Rotation Tests. When pain provocation was used as the indicator of a positive test during palpation of the cervical facet joints, moderate to substantial levels of reliability (κ range: 0.53–0.76) were observed. When patients were instructed not to provide feedback to the clinicians about pain provocation during facet joint palpation and clinicians relied solely on their qualitative assessment of segmental mobility, the level of reliability was lower (κ range: 0.45–0.53). Due to 100 % prevalence of negative findings, Kappa values could not be calculated for the Sharp-Purser test or the Unilateral C2 Spinous Kick Test. Conclusions Most physical examination procedures examined in this study demonstrated moderate to excellent levels of inter-examiner reliability. Palpation for segmental mobility without pain provocation demonstrated a lower level of reliability compared to palpation for pain provocation. Correlation with clinical findings is necessary to establish validity and the applicability of these procedures in clinical practice.

Objective To explore the kinematic biomechanical changes and symmetry in the left and right sides of the facet joints of lumbar spine segments under different functional loads. Methods Participants (n = 10) performing standing flexion and extension movements were scanned using computed tomography (CT) and dual fluoroscopy imagine system. Instantaneous images of the L3–S1 vertebrae were captured, and by matching a three‐dimensional CT model with contours from dual fluoroscopy images, in vivo facet joint movements were reproduced and analyzed. Translations and rotations of lumbar vertebral (L3 and L4) facet joints of data were compared for different loads (0, 5, 10 kg). The participants performed flexion and extension movements in different weight‐bearing states, the translations and angles changes were calculated respectively. Results From standing to extension, there were no statistical differences in rotation angles for the facet joint processes of different vertebral segment levels under different weight loads (P > 0.05). Mediolateral axis and cranio‐caudal translations under different weight loads were not statistically different for vertebral segment levels (P > 0.05). Anteroposterior translations for L3 (1.4 ± 0.1 mm) were greater than those for L4 (1.0 ± 0.1 mm) under the different load conditions (P = 0.04). Bilaterally, mediolateral, anteroposterior, and cranio‐caudal translations of the facet joints under different weights (0, 10 kg) for each segment level (L3 and L4) were symmetric (P > 0.05). From flexion to standing, there were no statistical differences in rotation angles for different weights (0, 5, 10 kg) for each level (L3 and L4) (P > 0.05). There were no statistical differences between mediolateral, anteroposterior, and cranio‐caudal translations at each segment level (L3 and L4) under different loads (P > 0.05). Under the condition of no weight (0 kg), L3 mediolateral translations on the left side (1.7 ± 1.6 mm) were significantly greater (P = 0.03) than those on the right side (1.6 ± 1.6 mm). Left side (1.0 ± 0.7 mm) L4 mediolateral translations were significantly smaller (P = 0.03) than those on the right side (1.1 ± 0.7 mm). There were no statistical differences between different weights for either anteroposterior and cranio‐caudal translations (P > 0.05). There were no statistical differences for mediolateral, anteroposterior, and cranio‐caudal translations for 10 kg (P > 0.05). Conclusion Lumbar spine facet joint kinematics did not change significantly with increased loads. Anteroposterior translations for L3 were greater than those for L4 of the vertebral segments are related to the coronal facet joint surface. Changes in facet surface symmetry indicates that the biomechanical pattern between facet joints may change., At present, many studies on facet joint movement patterns are based on the analysis of morphological data collected by imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI), cadaver specimens, and animal models. But these methods do not reflect true and accurate physiological data under weight‐bearing conditions. Using computed tomography (CT) and dual fluoroscopy imagine system (DFIS), in vivo facet joint movements were exactly reproduced and analyzed. The data collected are of great significance for studying the mechanisms of the lower lumbar spine to delay disease progression, exploration of pathogenesis of the lumbar degenerative disease, and guidance of surgical operation.

Introduction Radiofrequency ablation (RFA) is a demonstrated safe and effective treatment for chronic low back pain. RFA delivers high density electrical current near lumbar medial branch nerve. The success of RFA is contingent upon creating a lesion that overlaps the sensory nerve supplying the affected facet joint(s). Both bipolar-RFA and V-shaped active tip cannulas increase lesion size in experimental models. We describe successful application of concomitant bipolar and V-shaped lesions in a single patient with chronic low back pain caused by lumbar spondylosis. Case presentation An 81-year-old male with atrial fibrillation on chronic warfarin anticoagulation was previously treated with conventional monopolar lumbar facet RFA resulting in a 75% decrement in pain intensity exceeding eight months. Nine months after the procedure, his pain returned with similar pretreatment character and was unresponsive to additional physical therapy and acetaminophen. We elected to use a V-shaped cannula to maximize lesion diameter and lengthen intervals between anticoagulant abstinence to minimize the risk. Intraoperatively, a grounding-pad malfunction compelled us to convert to bipolar-RFA by placing a second adjacent V-shaped cannula, eliminating grounding-pad requirement. Bilateral bipolar medial branch RFA of L3–L4, L4–L5, L5–S1 nerves was performed between these two cannulas without further incident. The patient had sustained analgesia that lasted over twelve months resultant from treatment. Conclusions We herein describe a technique of combined bipolar-RFA utilizing proximally adjacent V-shaped cannulas. Both bipolar and V-shaped cannulas create larger lesions in experiments. While both techniques purport theoretical advantages, the clinical superiority of a combined technique warrants continued clinical investigation.

MRI was used to measure the changes in the angle of the facet joints of the lumbar spine and analyze the relationship between it and the herniated lumbar intervertebral disc. Analysis of the causes of lumbar disc herniation from the anatomy and morphology of the spine provides a basis for the early diagnosis and prevention of lumbar disc herniation. There is a certain correlation between the changes shown in MRI imaging of lumbar disc herniation and the TCM syndromes of lumbar intervertebral disc herniation. There is a correlation between the syndromes of lumbar disc herniation and the direct signs of MRI: pathological type, herniated position, and degree of herniation. Indirect signs with MR, nerve root compression and dural sac compression, are related. The MRI examination results can help syndrome differentiation to improve its accuracy to a certain extent. MRI has high sensitivity for the measurement of the angle of the facet joints of the lumbar spine and can be used to study the correlation between the changes of the facet joint angles and the herniated disc. Facet joint asymmetry is closely related to lateral lumbar disc herniation, which may be one of its pathogenesis factors. The herniated intervertebral disc is mostly on the sagittal side of the facet joint, and the facet joint angle on the side of the herniated disc is more sagittal. The asymmetry of the facet joints is not related to the central lumbar disc herniation, and the angle of the facet joints on both sides of the central lumbar disc herniation is partial sagittal.

Aims The aim of this study was to determine the differences in spinal imaging characteristics between subjects with or without lumbar developmental spinal stenosis (DSS) in a population-based cohort. Methods This was a radiological analysis of 2,387 participants who underwent L1-S1 MRI. Means and ranges were calculated for age, sex, BMI, and MRI measurements. Anteroposterior (AP) vertebral canal diameters were used to differentiate those with DSS from controls. Other imaging parameters included vertebral body dimensions, spinal canal dimensions, disc degeneration scores, and facet joint orientation. Mann-Whitney U and chi-squared tests were conducted to search for measurement differences between those with DSS and controls. In order to identify possible associations between DSS and MRI parameters, those who were statistically significant in the univariate binary logistic regression were included in a multivariate stepwise logistic regression after adjusting for demographics. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported where appropriate. Results Axial AP vertebral canal diameter (p < 0.001), interpedicular distance (p < 0.001), AP dural sac diameter (p < 0.001), lamina angle (p < 0.001), and sagittal mid-vertebral body height (p < 0.001) were significantly different between those identified as having DSS and controls. Narrower interpedicular distance (OR 0.745 (95% CI 0.618 to 0.900); p = 0.002) and AP dural sac diameter (OR 0.506 (95% CI 0.400 to 0.641); p < 0.001) were associated with DSS. Lamina angle (OR 1.127 (95% CI 1.045 to 1.214); p = 0.002) and right facet joint angulation (OR 0.022 (95% CI 0.002 to 0.247); p = 0.002) were also associated with DSS. No association was observed between disc parameters and DSS. Conclusion From this large-scale cohort, the canal size is found to be independent of body stature. Other than spinal canal dimensions, abnormal orientations of lamina angle and facet joint angulation may also be a result of developmental variations, leading to increased likelihood of DSS. Other skeletal parameters are spared. There was no relationship between DSS and soft tissue changes of the spinal column, which suggests that DSS is a unique result of bony maldevelopment. These findings require validation in other ethnicities and populations. Level of Evidence: I (diagnostic study) Cite this article: Bone Joint J 2021;103-B(4):725–733.

Background In patients with spinal metastases, kinematic instability is postulated to be a predictor of pathologic vertebral fractures. However, the relationship between this kinematic instability and the loss of spinal strength remains unknown. Methods Twenty-four 3-level thoracic and lumbar segments from 8 cadaver spines from female donors aged 47 to 69 years were kinematically assessed in axial compression (180 N) and axial compression with a flexion or extension moment (7.5 Nm). Two patterns of lytic defects were mechanically simulated: (1) a vertebral body defect, corresponding to Taneichi model C (n = 13); and (2) the model-C defect plus destruction of the ipsilateral pedicle and facet joint, corresponding to Taneichi model E (n = 11). The kinematic response was retested, and compression strength was measured. Two-way repeated-measures analysis of variance was used to test the effect of each model on the kinematic response of the segment. Multivariable linear regression was used to test the association between the kinematic parameters and compressive strength of the segment. Results Under a flexion moment, and for both models C and E, the lesioned spines exhibited greater flexion range of motion (ROM) and axial translation than the control spines. Both models C and E caused lower extension ROM and greater axial, sagittal, and transverse translation under an extension moment compared with the control spines. Two-way repeated-measures analysis revealed that model E, compared with model C, caused significantly greater changes in extension and torsional ROM under an extension moment, and greater sagittal translation under a flexion moment. For both models C and E, greater differences in flexion ROM and sagittal translation under a flexion moment, and greater differences in extension ROM and in axial and transverse translation under an extension moment, were associated with lower compressive strength of the lesioned spines. Conclusions Critical spinal lytic defects result in kinematic abnormalities and lower the compressive strength of the spine. Clinical relevance This experimental study demonstrates that lytic foci degrade the kinematic stability and compressive strength of the spine. Understanding the mechanisms for this degradation will help to guide treatment decisions that address inferred instability and fracture risk in patients with metastatic spinal disease.

Objective 1) To describe a simplified multidisciplinary grading system for the most clinically relevant lumbar spine degenerative changes. 2) To measure the inter-reader variability among non-radiologist spine experts in their use of the classification system for interpretation of a consecutive series of lumbar spine magnetic resonance imaging (MRI) examinations. Methods ATS multidisciplinary and collaborative standardized grading of spinal stenosis, foraminal stenosis, lateral recess stenosis, and facet arthropathy was developed. Our institution’s picture archiving and communication system was searched for 50 consecutive patients who underwent non-contrast MRI of the lumbar spine for chronic back pain, radiculopathy, or symptoms of spinal stenosis. Three fellowship-trained spine subspecialists from neurosurgery, orthopedic surgery, and physiatry interpreted the 50 exams using the classification at the L4–L5 and L5–S1 levels. Inter-reader agreement was assessed with Cohen’s kappa coefficient. Results For spinal stenosis, the readers demonstrated substantial agreement (κ = 0.702). For foraminal stenosis and facet arthropathy, the three readers demonstrated moderate agreement (κ = 0.544, and 0.557, respectively). For lateral recess stenosis, there was fair agreement (κ = 0.323). Conclusions A simplified universal grading system of lumbar spine MRI degenerative findings is newly described. Use of this multidisciplinary grading system in the assessment of clinically relevant degenerative changes revealed moderate to substantial agreement among non-radiologist spine physicians. This standardized grading system could serve as a foundation for interdisciplinary communication.

BackgroundLumbar interbody fusion is a standard technique for treating degenerative lumbar disorders involving instability. Due to its invasiveness, a minimally invasive technique, extraforaminal lumbar interbody fusion (ELIF), was introduced. On surgically approaching posterolaterally, the posterior muscles and spinal canal are barely invaded. Despite its theoretical advantage, ELIF is technically demanding and has not been popularised. Therefore, we developed a microendoscopy-assisted ELIF (mELIF) technique which was designed to be safe and less invasive. Here, we aimed to report on the surgical technique and clinical results.MethodsUsing a posterolateral approach similar to that of lateral disc herniation surgery, a tubular retractor, 16 or 18 mm in diameter, was placed at the lateral aspect of the facet joint. The facet joint was partially excised, and the disc space was cleaned. A cage and local bone graft were inserted into the disc space. All disc-related procedures were performed under microendoscopy. The spinal canal was not invaded. Bilateral percutaneous screw-rod constructs were inserted and fixed.ResultsFifty-five patients underwent the procedure. The Oswestry Disability Index and visual analogue scale scores greatly improved. Over 90% of the patients obtained excellent or good results based on Macnab’s criteria. There were neither major adverse clinical effects nor the need for additional surgery.ConclusionsmELIF is minimally invasive because the spinal canal and posterior muscles are barely invaded. It produces good clinical results with fewer complications. This technique can be applied in most single-level spondylodesis cases, including those involving L5/S1 disorders.

Background Facet tropism (FT) refers to the difference in the orientation of facet joints with respect to each other in the sagittal plane. FT leads to unequal biomechanical forces on facet joint and intervertebral disc during rotation and other physiologic movements. Most of the studies have reported the incidence of FT in the lumbar spine to vary between 40% and 70%, with L4-5 level being the most commonly afflicted level. The objective of this study was to find the association between FT and various lumbar and cervical degenerative disorders. Methods A systematic search of PubMed was performed with the keywords “facet tropism” and “facet asymmetry.” Data for meta-analysis were extracted from the studies to obtain pooled impact of FT on lumbar disc herniation (LDH) and lumbar degenerative spondylolisthesis (LDS). Results Eighty-two articles were included in the systematic review and 18 studies had the required data to be included in the meta-analysis. The pooled standard mean difference between FT angles in patients with or without LDH was 0.31 with (P = 0.04). The pooled odds ratio for FT in patients with LDH was 3.27 with (P = 0.02). Subgroup analysis showed that there is no significant difference in the L3/4, L4/5, and L5S1 subgroups. The pooled standard mean difference between FT angles in patients with or without LDS was 0.54 (P = 0.009). Conclusions FT is significantly associated with LDH and LDS along with various other lumbar and cervical degenerative diseases.

Study design Multicenter double-blind randomized sham-controlled trial. Objective To assess the efficacy of radiofrequency (RF) denervation of the cervical facet joints in chronic cervical facet joint pain. Summary of background data One randomized controlled trial showed efficacy of RF denervation in whiplash-associated disease. There are no randomized controlled trials on RF denervation in patients with chronic cervical facet joint pain. Methods Patients were randomized to receive RF denervation combined with bupivacaine (intervention group) or bupivacaine alone (control group). In the intervention group, an RF thermal lesion was made at the cervical medial branches after the injection of bupivacaine. The primary outcome was measured at 6 months and consisted of pain intensity, self-reported treatment effect, improvement on the Neck Disability Index, and the use of pain medication. Duration of effect was determined using telephone interviews. Results We included 76 patients. In the intervention group, 55.6% showed > 30% pain decrease versus 51.3% in the control group (P = 0.711); 50.0% reported success on the Patients' Global Impression of Change in the intervention group versus 41.0% (P = 0.435); the Neck Disability Index was 15.0 ± 8.7 in the intervention group compared with 16.5 ± 7.2 (P = 0.432), the need for pain medication did not differ significantly between groups (P = 0.461). The median time to end of treatment success for patients in the RF group was 42 months, compared with 12 months in the bupivacaine group (P = 0.014). Conclusions We did not observe significant differences between RF denervation combined with injection of local anesthesia compared with local anesthesia only at 6 months follow-up. We found a difference in the long-term effect after 6 months follow-up in favor of the RF treatment.Level of Evidence: 2.

Spinal osteochondromas are very rare, and they present with nonspecific localized pain owing to bone involvement. Diagnosis is made based on direct X-ray and computed tomography (CT) imaging of the exophytic bone lesion with pedunculated or sessile structure. Although asymptomatic patients can be observed, surgical excision is the main treatment modality. We present the case of a 34-year-old man with solitary thoracic osteochondroma. The patient presented with complaints of pain in the legs, numbness, and inability to walk. The diagnosis was confirmed with CT imaging showing calcified heterogeneous bone lesion originating from the left side of T1-2 facet joint. After total excision, histopathological examination revealed the diagnosis of osteochondroma. No new clinical or radiological findings were detected in the 10-month follow-up.

Objective To evaluate the effect of inserting epidemiological information into lumbar spine imaging reports on subsequent nonsurgical and surgical procedures involving the thoracolumbosacral spine and sacroiliac joints. Design Analysis of secondary outcomes from the Lumbar Imaging with Reporting of Epidemiology (LIRE) pragmatic stepped-wedge randomized trial. Setting Primary care clinics within four integrated health care systems in the United States. Subjects 238,886 patients ≥18 years of age who received lumbar diagnostic imaging between 2013 and 2016. Methods Clinics were randomized to receive text containing age- and modality-specific epidemiological benchmarks indicating the prevalence of common spine imaging findings in people without low back pain, inserted into lumbar spine imaging reports (the “LIRE intervention”). The study outcomes were receiving 1) any nonsurgical lumbosacral or sacroiliac spine procedure (lumbosacral epidural steroid injection, facet joint injection, or facet joint radiofrequency ablation; or sacroiliac joint injection) or 2) any surgical procedure involving the lumbar, sacral, or thoracic spine (decompression surgery or spinal fusion or other spine surgery). Results The LIRE intervention was not significantly associated with subsequent utilization of nonsurgical lumbosacral or sacroiliac spine procedures (odds ratio [OR] = 1.01, 95% confidence interval [CI] 0.93–1.09; P = 0.79) or any surgical procedure (OR = 0.99, 95 CI 0.91–1.07; P = 0.74) involving the lumbar, sacral, or thoracic spine. The intervention was also not significantly associated with any individual spine procedure. Conclusions Inserting epidemiological text into spine imaging reports had no effect on nonsurgical or surgical procedure utilization among patients receiving lumbar diagnostic imaging.

Background The treatment of unilateral CFD in patients without neurologic deficits remains controversial, especially in the choice of the best surgical approach. Our objective is to determine the way spine surgeons from Latin America manage this condition. Methods A survey regarding management and surgical strategies was conducted by the AO Spine Latin American Trauma Study Group considering the treatment of unilateral CFD. Results All AO Spine Latin American Trauma Study Group members were sent a link to the survey, among whom 285 replied, with 197 respondents answering all the questions. Nonsurgical management was considered by 25% of the surgeons. The majority stated that magnetic resonance imaging is necessary (65%) to treat this type of patient. A posterior approach was preferred by 44%, an anterior approach by 29%, and a combined approach by 25%, while 2.2% did not answer. Traction was not used by the majority of respondents (62%). In the setting of an anterior disk herniation, the majority of surgeons preferred to employ an anterior (45%) or combined (44%) approach versus an isolated posterior approach (only 0.5%). Comparing early versus late cervical trauma, fewer surgeons adopted an isolated anterior approach with the latter (29% vs. 15%). Conclusions Wide variations exist in the management of unilateral CFD by Latin American surgeons, with early injuries generally treated using either an anterior or posterior approach and treated early but after an MRI, while a combined approach is used more commonly with late injuries. Either an anterior or combined approach is used when disk herniation is present.

Purpose To describe a modified minimally invasive spine (MIS) procedure to treat lumbar developmental spinal stenosis (DSS) to achieve complete decompression and fusion. The method preserves the muscles, ligaments, and most of the bony structures. DSS is not considered a good indication for MIS procedures and few reports discuss alternative treatments. Because MIS has the advantages of low blood loss, rapid recovery, and short hospital stay, it would be ideal for DSS. Methods After confirming the screw positions, we placed a tube retractor in the facet joint on the decompressed side. The inferior facet joint and part of the superior joint of the lower segment were removed, the spinal canal was carefully exposed under a microscopic view, and fusion was performed through Kambin’s triangle. Next, the operation table was rotated to the contralateral side and angled to approximately 15–20 degrees. We then tilted the tube retractor in the facet joint toward the operation side by 15–20 degrees, which provided access to the contralateral canal for decompression. The ligament flavum was carefully removed and the dural sac was gently retracted to expose the lateral recess on the other side. We then examined the nerve root on the contralateral side to ensure there was no compression. Results Eight patients with lumbar DSS were treated using this method. Patients' neurological symptoms improved greatly without complications and patients were able to walk the day after surgery. The inner plate of the contralateral lamina and muscle as well as most of the ligaments that contribute to stability were preserved. Conclusion This modified MIS decompression procedure successfully treated DSS by providing spinal canal decompression and preserving most of the stabilizing structures.

Objective By observing the 3D anatomy of normal adult cervical facet joints, using the picture archiving and communication system to measure its 3D parameters and discussing its clinical significance, the aim of this study was to provide a reliable morphological basis for the design and manufacture of lower cervical facet joint interface distractors. Methods We selected 200 patients who underwent cervical spine 3D spiral computed tomography (CT) examination in the imaging department of our hospital from September 2019 to May 2020 and whose spiral CT images showed no cervical spinal canal stenosis, cervical disc herniation, obvious bone hyperplasia, or infection. The anterior and posterior diameters of the facet joints on both sides of the cervical spine, the space between the joints, and the left and right diameters were measured on the sagittal, cross-sectional and coronal planes after reconstruction with 3D spiral CT. Results The anterior and posterior diameters of the facet joints of the cervical spine, the space between the joints, and the left and right diameters all increased from top to bottom along the cervical spine. The 3D parameters of the C2-3~C6-7 segments were significantly different between the male and female groups. Conclusion The anteroposterior diameter, joint space interval, and left and right diameter of cervical facet joints are different in each segment and between the sexes. The lower cervical facet joint interface fusion device designed according to the measurement results can fully meet the needs of most patients.

OBJECTIVEFacet cysts may represent a sign of intrinsic facet disease and instability, increasing the importance of less-invasive approaches that limit tissue dissection and improve visualization. The authors developed an intraoperative cyst-dyeing technique, involving the injection of indigo carmine from the facet joint into the cyst, as an adjunct during decompression. This study aimed to evaluate the clinical outcomes and perioperative complication rates of microendoscopic spinal decompression for lumbar spinal stenosis (LSS) and lumbar foraminal stenosis (LFS), caused by facet cysts and to elucidate the efficacy of the cyst-dyeing method in microendoscopic surgery for facet cysts.METHODSForty-eight consecutive patients who underwent surgical treatment with microendoscopic decompression for symptomatic LSS or LFS caused by facet cysts from 2011 to 2018 were reviewed. These patients were divided into two groups: a group that did not receive dye (N), with the patients undergoing surgery from April 2011 to May 2015; and a group that received dye (D), with patients undergoing surgery from June 2015 to March 2018. The authors evaluated the operative time, blood loss, perioperative complications, visual analog scale scores for low-back and leg pain, and Japanese Orthopaedic Association scores. Surgical outcome was evaluated 2 years postoperatively and was compared between groups D and N.RESULTSThe clinical outcomes were generally excellent or good. Group N consisted of 36 patients and group D of 12 patients. Comparing the clinical results, it was found that the cyst-dyeing method reduced the perioperative complication rate, including reduction in dural tears to 0%, and shortened the average operative time by approximately 40 minutes.CONCLUSIONSIn this study, the authors demonstrated that the clinical outcomes of microendoscopic spinal decompression in patients with LSS or LFS caused by facet-joint cysts are generally favorable. Additionally, the adjunctive cyst-dyeing method effectively delineated the cystic and dural boundaries, facilitating safer and more effective cyst separation and neural decompression. Microendoscopic surgery combined with this novel facet cyst-dyeing method is a safe and effective minimally invasive technique for facet-joint cysts.

Objective We simulated the trajectory for an L5/S1 percutaneous endoscopic transforaminal discectomy (PETD) to guide decision-making for the surgery approach. Methods Twenty-three patients with L5/S1 lumbar disc herniation were included in the study. The patients all underwent thin-section computed tomography scans, after which data were collected for 3-dimensional reconstruction. Simulations of the trajectory for the L5/S1 PETDs were generated and the hindrance of surrounding anatomic structures was evaluated. Results Preoperative simulation showed that 14 patients were considered suitable for lumbar PETD. Nine patients were not considered suitable for PETD surgery according to the simulation. Factors affecting the trajectory included high iliac crest in 5 patients, L5 transverse process in 3 patients, and hypertrophic L5-S1 facet joint in 1 patient. Conclusions Preoperative simulation of the trajectory for L5/S1 PETD was helpful in the decision-making for the surgical approach.

Background The principles of choosing an appropriate implant height remain controversial in total cervical disc replacement (TDR). By performing an in vitro biomechanical study and exploring the biomechanical impact of implant height on facet joint and motion function, the study aimed to offer valid proposals regarding implant height selection during TDR. Methods A total of 6 fresh-frozen male cadaveric cervical spines (C2–C7) with 5 mm intervertebral disc height at C5/6 level were enrolled in the study. Specimens with the intact condition and with different height artificial discs were tested. Facet joint pressures and range of motion under each condition were recorded using a specialized machine. Results The artificial disc heights that were involved in this study were 5 mm, 6 mm, and 7 mm. The range of motion decreased along with the increment of implant height, while facet joint pressure showed an opposite trend. Specimens with a 5 mm implant height could provide a similar range of motion (11.8° vs. 12.2° in flexion-extension, 8.7° vs. 9.0° in rotation, 7.9° vs. 8.2° in lateral bending) and facet joint pressure (27.8 psi vs. 25.2 psi in flexion, 59.7 psi vs. 58.9 psi in extension, 24.0 psi vs. 22.7 psi in rotation, 32.0 psi vs. 28.8 psi in lateral bending) compared with intact specimens. Facet joint pressure of specimens with 6 mm implant height (≥ 1 mm in height) increased during flexion at the C5–6 segment (30.4 psi vs. 25.2 psi, P = 0.076). However, specimens with 7 mm implant height (≥ 2 mm in height) showed a significant reduction in motion (9.5° vs. 12.2° in flexion-extension, P < 0.001) and increment of facet joint pressure at C5–6 segment (44.6 psi vs. 25.2 psi in flexion, 90.3 psi vs. 58.9 psi in extension, P < 0.0001) and adjacent segments. Conclusions This study suggested that an appropriate artificial disc height can achieve near-normal biomechanical properties and is recommended. We should be very cautious when using artificial discs ≥ 1 mm in height compared to normal. However, implants ≥ 2 mm in height compared to normal significantly increased the facet joint pressure and decreased the range of motion; therefore, it should not be used in clinical practice.

Background The long-term outcome of facet joint replacement (FJR) still is to be proven. Methods We present a prospective case series of 26 (male-to-female ratio of 1:1; mean age: 61 years) patients undergoing FJR with a follow-up of at least 1 year (range: 12–112; mean: 67 months). Visual analog scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), and the 12-Item Short Form Health Survey (SF-12) were applied pre- and postoperatively (after 3, 6, and 12 months) as well as at the last follow-up (N = 24). Using X-rays of the lumbar spine (N = 20), the range of motion (ROM) and disk height in the indicator and adjacent levels were assessed. Results FJR was performed at L3/L4 (N = 7), L4/L5 (N = 17), and L5/S1 (N = 2). Mean VAS (mm) for back pain decreased from 71 to 18, mean VAS for right leg pain from 61 to 7, and from 51 to 3 for the left leg. Mean ODI dropped from 51 to 22% (for all p Conclusions In selected cases, long-term results of FJR show good outcome concerning pain, quality of life, preservation of lumbar spine motion, and protection of adjacent level.

Background and Objective Learning a new technique in neurosurgery is a big challenge especially for trainees. In recent years, simulations and simulators got into the focus as a teaching tool. Our objective is to propose a simulator for placement of cortical bone trajectory (CBT) screws to improve results and reduce complications.Methods We have created a platform consisting of a sawbone navigated with a 3D fluoroscope to familiarize our trainees and consultants with CBT technique and later implement it in our department. Objective Structured Assessment of Technical Skills (OSATS) and Physician Performance Diagnostic Inventory Scale (PPDI) were obtained before and after the use of the simulator by the five participants in the study. Patients who were operated on after the implementation of the technique were retrospectively reviewed.Results During the simulation, there were 4 cases of pedicle breach out of 24 screws inserted (16.6%). After having completed simulation, participants demonstrated an improvement in OSATS and PPDI (p = 0.039 and 0.042, respectively). Analyzing the answers to the different items of the tests, participants mainly improved in the knowledge (p = 0.038), the performance (p = 0.041), and understanding of the procedure (p = 0.034). In our retrospective series, eight patients with L4–L5 instability were operated on using CBT, improving their Oswestry Disability Index (ODI) score (preoperative ODI 58.5 [SD 16.7] vs. postoperative ODI 31 [SD 13.4]; p = 0.028). One intraoperative complication due to a dural tear was observed. In the follow-up, we found a case of pseudoarthrosis and a facet joint violation, but no other complications related to misplacement, pedicle fracture, or hardware failure.Conclusion The simulation we have created is useful for the implementation of CBT. In our study, consultants and trainees have valued very positively the learning obtained using the system. Moreover, simulation facilitated the learning of the technique and the understanding of surgical anatomy. We hope that simulation helps reducing complications in the future.

BACKGROUND CONTEXT A few studies have already investigated the influences of functional structures of the cervical spine on its biomechanical behavior. In most studies, this has been done by measuring the range of motion. However, this parameter lacks of qualitative information about the overall kinematic behavior, such as coupled motions or translations. These data are essential for future development of cervical implants and surgical techniques. PURPOSE An investigation of the influences of cervical structures on the kinematic behavior of the cervical spine under in vivo conditions is almost impossible due to ethical reasons. Therefore, an in vitro study was conducted which allowed the analysis of these influences using three-dimensional helical axes. STUDY DESIGN/SETTING An in vitro test applying pure moments on mono-segmental specimens was designed in order to investigate the influences of a series of structures on the kinematic behavior of the cervical spine using three-dimensional helical axes. METHODS In this study we extracted motion segments C2–C3, C4–C5, and C6–C7 from 6 human cadaveric specimens with an average age of 48 years. The specimens were carefully selected using X-ray images. For the in vitro experiments, seven states were defined. The first state represented the intact state of each specimen. The remaining six states correspond with the subsequent resection of the following structures in the given order: interspinous ligament, ligamentum flavum, facet capsule, vertebral arch, posterior longitudinal ligament, and anterior longitudinal ligament. Each state was tested using a well-established spine tester. Each test sequence included 3.5 quasi-static motion cycles in all three bending directions using pure moments of 1 Nm. All motions were recorded using a motion tracking device and six reflective markers which were attached to the specimens. The recordings were then used to calculate the 3D helical axes, which were matched with the X-ray images. Due to the small number of specimens, qualitative results, such as the helical axes, were analyzed using descriptive statistics. RESULTS In general, the overall range of motion was increased in all loading directions due to the resection steps. The least change in the kinematic behavior of the cervical spine was observed during flexion/extension. For lateral bending and axial rotation the greatest change in the pattern of the helical axes was observed during the resection of the vertebral arch. For some specimens, however, typical patterns regarding the orientation of the helical axes remained until the last state. For lateral bending, it could be observed that the deviation in the axes’ orientation increased whereas for axial rotation it decreased. CONCLUSION Resection of the cervical ligaments are much less crucial than the removal of guiding structures such as the facet joint. Furthermore, coupled motions not only result from the orientations of the articular surfaces of the facet joints but also from the overall shape of the cervical vertebrae including the uncinate processes. CLINICAL SIGNIFICANCE It is well-known that coupled motions play a substantial role in cervical kinematics. However, the influences of cervical structures on the overall kinematic behavior of the cervical spine are not yet fully understood. Knowledge of these influences could help to reduce or even prevent iatrogenic degeneration after surgical intervention. Furthermore, the data provided by this study can be helpful for future developments of cervical implants as well as finite element models for more advanced numerical investigations.

Degeneration is a hallmark of painful joint disease and is mediated by many proteases that degrade joint tissues, including collagenases. We hypothesized that purified bacterial collagenase would initiate nociceptive cascades in the joint by degrading the capsular ligament’s matrix and activating innervating pain fibers. Intra-articular collagenase in the rat facet joint was investigated for its effects on behavioral sensitivity, joint degeneration, and nociceptive pathways in the peripheral and central nervous systems. In parallel, a co-culture collagen gel model of the ligament was used to evaluate effects of collagenase on microscale changes to the collagen fibers and embedded neurons. Collagenase induced sensitivity within one day, lasting for 3 weeks (p

The use of the 3D orientation angle of the calcaneal posterior subtalar (PTC) joint facet might be superior to the Böhler's angle to evaluate the quality of reduction after performing an open reduction and internal fixation (ORIF) of displaced intra-articular calcaneal fractures (DIACFs).

Objective Thoracic spinal pain is common, and patients with this type of pain have limited therapeutic options. The cohort in this study received diagnostic intra-articular zygapophysial joint injections leading to thermal neurotomy to the medial branch nerves to demonstrate improved pain as well as physical and psychological function. Design A consecutive cohort from 2012 to 2018 with retrospective analysis of prospectively gathered data. Setting A private multidisciplinary pain clinic with referrals from primary care. Results Forty-six complete data sets from 39 patients were found using a pre-procedure and 3-month post-procedure questionnaire. Further follow-up results were found for the dual primary outcomes of duration of ≥50% relief using a numeric rating scale (NRS) for the entire group. The group was then divided into three subgroups of T1/2–T3/4, T4/5–T8/9, and T9/10–T12/L1. Success rates of 63% for ≥3 months of ≥50% relief and 46% for ≥6 months of ≥50% relief were found, for an average duration of 7.8 months. Group mean change in the NRS was 6.7, decreasing to 4.3 (P36% improvement in scores. Conclusion This cohort demonstrates that there is a pragmatic diagnostic and therapeutic option available for patients with thoracic zygapophysial joint pain that can achieve 50–100% of pain relief in 63% of patients with improved physical and psychological function.

Study design Cross-sectional study. Objective The aim of this study was to evaluate the actual prevalence of degenerative spinal changes and their association with age in a cohort of professional soccer players. Summary of background data Presently, there are data that athletes have more degenerative changes than nonathletes; however, the research examining the prevalence of degenerative spinal conditions among professional elite soccer players is scarce. Methods Professional male soccer players were included in the study (n = 40, average age 26,6 ± 4,5 years, average height 18 ± 0.07 m, weight 76.7 ± 7.1 kg). Lumbosacral spine MRI scanning at the L1-S1 level has been performed. Two radiologists with at least 7 years of experience of working with athletes evaluated all images independently of each other. Results 92.5% (n = 37) of soccer players had ≥1 spinal degenerative condition. Thirty-five percent (n = 14) of players had three to five, and 50% (n = 20) had six or more conditions. The average age of players who had six or more conditions was significantly higher than those who had zero to five or three to five conditions-28.1 ± 4.8 years versus 25.1 ± 3.6 years (P = 0.029), and 24.8 ± 3.6 years, respectively.Kruskal-Wallis test has shown no association between the number of degenerative conditions and weight (P = 0.98) as well as body mass index (P = 0.99). The age was associated with degenerative changes (P = 0.008).Disc desiccation was the most common pathologic condition, which was found in 82.5% of athletes. Facet joint arthropathy and spondylosis were present in 70, and 50% of the studied lumbar spine MRI scans, respectively. The spondylolysis prevalence of 20% was noted. Conclusion Elite professional soccer players demonstrate a high prevalence of asymptomatic degenerative lumbar spinal degenerative changes, which are significantly associated with age. These conditions might lead to the development of symptomatic lower back pain, given the high-intensity exercise required in professional soccer. It is presently unclear what measures might be applied for the primary prevention of these degenerative spinal conditions.Level of Evidence: 4.