Facet Joint Injury Research Articles

L5-S1 facet joint pathology in pelvic ring injuries.

The authors believe that the L5-S1 facet joint injury in the setting of pelvic fractures is underappreciated by orthopedic traumatologists. The purpose of this study was to draw attention to the L5/S1 facet joint in the setting of pelvic ring injuries. This was a retrospective comparative study of all patients greater than or equal to 18years of age with an acute pelvic ring injury (AO/OTA 62 B to C) presenting to a single level I trauma center. The primary objective was to determine demographic and injury characteristics associated with L5-S1 facet joint injuries in patients with pelvic ring injuries. The secondary objective was to determine the proportion of L5-S1 facet joint injuries that were missed on initial radiographic workup. There were 476 patients included in the analysis, 53 (11.1%) of whom had an L5-S1 facet joint injury. Patients with an L5-S1 injury were more likely to be younger (44.1 vs. 53.2years, p = 0.001) and experience a high energy mechanism of injury (95.0% vs. 78.0%, p = 0.002). Certain injury patterns were associated with L5-S1 facet joint injuries: any sacral fracture (96.2% vs. 73.8%, p < 0.001), Denis zone 2 fractures (43.4% vs. 20.1%, p < 0.001), Denis zone 3 fractures (34.0% vs. 4.7%, p < 0.001), bilateral displaced sacral fractures (18.9% vs. 3.5%, p < 0.001), and L5 transverse process fractures (64.2% vs. 18.0%, p < 0.001). Only 16.0% of radiology reports identified an L5-S1 injury. Orthopedic traumatologists should scrutinize imaging for L5-S1 facet joint injuries in the presence of pelvic ring injuries, especially in patients with certain sacral fracture patterns.

Surgical management strategies for unstable sacral fractures: Case series and surgical guideline

IntroductionUnstable sacral fractures usually have posterior pelvic and spinopelvic instability, which usually be classified as AO type C. There are many controversial points concerning the management of these fractures due to their rarity. Herein, we retrospectively review cases of this injury and propose a surgical guideline. Case presentationA 37-year-old female experienced back pain after a motor vehicle accident. Diagnostic imaging revealed an AO type C1 sacral fracture, Isler subtype 2a (case No. 7). Preoperative CT scan and CT reconstruction images showed a longitudinal fracture with a simple intraarticular fracture of the left S1 superior facet. Although the patient sustains a lumbosacral facet joint injury, the lumbosacral motion seems preservable after healing. The triangular osteosynthesis was chosen because it provides both transverse plane and vertical plane stability. The patient was allowed to continue weight-bearing ambulation after the operation. To maintain lumbosacral motion, the spinopelvic rod was removed in the postoperative seventh month. DiscussionThe unstable sacral fracture might have instability in both the vertical and transverse planes. The fixation construct should provide both vertical and transverse stability. Regarding vertical fixation, it might cost a loss of lumbosacral motion, which the treating surgeon has to consider. The lumbosacral injury is sometimes trivial, and long-term lumbosacral motion is expectable. So, permanent spinopelvic fixation is not necessary. The patient's character is also an important factor. Whether the patient needs or does not need early progressive weight bearing after the operation determines the fixation method. ConclusionUnstable sacral fractures are rare conditions usually resulting from a high-energy injury. We have proposed a surgical management strategy for this group of fractures with an optimal fixation method based on three factors: 1) fracture morphology, 2) lumbosacral integrity, and 3) concomitant injury.

What are the Risk Factors for Residual Pain After Percutaneous Vertebroplasty or Kyphoplasty? A Meta-Analysis

BackgroundAlthough many risk factors for residual pain following percutaneous vertebroplasty or kyphoplasty have been reported in many studies, research methods and cohorts differ greatly. A previous meta-analysis identified patient- and operation-specific risk factors for residual pain. This study aimed to examine the available data and identify significant risk factors for residual pain after percutaneous vertebroplasty or kyphoplasty. MethodsPubMed, EMBASE, Web of Science, and the Chinese Wanfang Database were searched for relevant research in English and Chinese, and full-text publications including patients with and without residual pain were compared. Only studies presenting odds ratios from multivariate analysis of residual pain data were considered. To evaluate the impact of the results of the selected articles, Review Manager 5.4 was used. ResultsTwelve publications including a total of 3120 patients met the requirements. The meta-analysis examined ten factors associated with residual pain and categorized them as either patient- or operation-associated factors. Thoracolumbar fascia injury, intravertebral vacuum cleft, depression, and number of fractured vertebrae were all significant patient-associated parameters for residual pain. Significant operation-associated risk factors included bone cement distribution and intraoperative facet joint injury. ConclusionsIn this meta-analysis, we identified several significant risk factors for residual pain after percutaneous vertebroplasty or kyphoplasty. These findings may be helpful for patient counseling and surgical planning.

Secondary Dislocations in Type B and C Injuries of the Subaxial Cervical Spine: Risk Factors and Treatment

Introduction: This study analyzed the incidence of secondary dislocations (sDLs) after surgical stabilization of AO Spine type B and C injuries of the subaxial cervical spine (sCS). Materials and Methods: Patients treated for injuries of the sCS from 2010 to 2020 were retrospectively analyzed for the incidence of sDL within 60 days after first surgery. A univariate analysis of variables potentially influencing the risk of sDL was performed. Patients with solitary anterior stabilization underwent subgroup analysis. The treatment of sDLs was described. Results: A total of 275 patients were included. sDLs occurred in 4.0% of patients (n = 11) in the total sample, most frequently after solitary anterior stabilization with 8.0% (n = 10, p = 0.010). Only one sDL occurred after combined stabilization and no sDLs after posterior stabilization. In the total sample and the anterior subgroup, variables significantly associated with sDL were older age (p = 0.001) and concomitant unstable facet joint injury (p = 0.020). No neurological deterioration occurred due to sDL and most patients were treated with added posterior stabilization. sDL is frequent after solitary anterior stabilization and rare after posterior or combined stabilization. Discussion: Patients of higher age and with unstable facet joint injuries should be followed up diligently to detect sDLs in time. Neurological deterioration does not regularly occur due to sDL, and most patients can be treated with added posterior stabilization.

Detailed observation of anatomical location and pattern in Hangman’s fracture based on computed tomography three-dimensional reconstruction

ObjectiveTo observe the precise anatomical location and pattern of the fracture lines in Hangman’s fracture.MethodsThree-dimensional computed CT images of 210 patients with Hangman’s fracture were collected. According to the involvement of anatomical structures, the injuries were classified into facet joint injury and pure bony injury. The C2 ring was also divided into: anterior, middle, and posterior elements. The anatomical structures involvement and fracture patterns were observed.ResultTotal 520 anatomical structures injuries were involved in 210 patients Hangman’s fractures, including 298 facet joints injuries (57.3%) and 222 bony injuries (42.7%). The most common facet joints injury was superior articular facet injury of C2, and the most common pure bony injury was pediculoisthmic component fracture. The injuries of anterior element (60.6%) were more common than that of middle (20.4%) or posterior (19.0%) element. One injury in anterior element on one side and another injury located in the anterior, middle or posterior element other side was the most common fracture pattern. Injury of middle element on one side with another injury located in the middle or posterior element could be also observed.ConclusionIn Hangman’s fractures, fracture lines could occur in any part of C2 ring. Facet joints injuries were more common than pure bony injuries, and the injuries of anterior element were also more common than that of middle or posterior element. The high prevalence of facet joints injuries means that most of Hangman’s fractures may be involved with intra-articular injuries.

A nomogram for predicting residual low back pain after percutaneous kyphoplasty in osteoporotic vertebral compression fractures.

The cause of residual low back pain in patients with osteoporotic vertebral compression fractures(OVCFs) after PKP remains highly controversial, and our goal was toinvestigate the most likely cause and to develop a novel nomogram for the prediction ofresidual low back pain and to evaluate the predictive performance of the model. The clinical data of 281 patients with OVCFs who underwent PKP at our hospital from July 2019 toJuly 2020 were reviewed. The optimal logistic regression model was determined by lassoregression for multivariate analysis, thus constructing a nomogram. Bootstrap was used toperfomance the internal validation; receiver operating characteristic (ROC) curve, calibration curve, anddecision curve analysis (DCA) were used to assess the predictive performance and clinical utility of themodel, respectively. Temporal external validation of the model was also performed using retrospectivedata from 126 patients who underwent PKP at our hospital from January 2021 to October 2021. Lasso regression cross-validation showed that the variables with non-zero coefficients were thenumber of surgical vertebrae, preoperative bone mineral density (pre-BMD), smoking history,thoracolumbar fascia injury (TLFI), intraoperative facet joint injury (FJI), and postoperative incompletecementing of the fracture line (ICFL). The above factors were included in the multivariate analysis andshowed that the pre-BMD, smoking history, TLFI, FJI, and ICFL were independent risk factors forresidual low back pain (P < 0.05). The ROC and calibration curve of the original model and temporalexternal validation indicated a good predictive power of the model. The DCA curve suggested that themodel has good clinical practicability. The risk prediction model has good predictive performance and clinical practicability, which canprovide a certain basis for clinical decision-making in patients with OVCFs.

Indications, Contraindications, and Complications of Biportal Endoscopic Decompressive Surgery for the Treatment of Lumbar Stenosis: A Systematic Review

Biportal endoscopic spine surgery is gaining popularity in managing degenerative lumbar diseases and has optimal indications and contraindications. The perioperative complications related to the biportal endoscopic approach affect the postoperative outcomes. Therefore, this study aimed to review the indications, contraindications, and complications of biportal endoscopic decompression for lumbar stenosis. For this systematic review, articles on biportal endoscopic decompressive surgery for lumbar stenosis, including central, lateral recess and foraminal stenoses, were searched for and reviewed. Additionally, the complications, indications, and contraindications of biportal endoscopic surgery for lumbar stenosis were reviewed. Forty-one articles were included in this study. The indications for biportal endoscopic decompression are central lumbar stenosis, central stenosis with lipomatosis, lateral recess stenosis, foraminal stenosis, and the far-out syndrome. The contraindications include trauma, infection, tumor, instability, high-grade spondylolisthesis, isthmic spondylolisthesis, and severe scoliosis. Perioperative complications are typically minor; major complications include durotomy, epidural hematoma, incomplete decompression, infection, facet joint injury, neural injury, increased epidural pressure, and postoperative instability. Favorable indications for a biportal endoscopic approach are central lumbar, lateral recess, foraminal, extraforaminal stenoses, and the Bertolotti syndrome. Incidental durotomy and postoperative epidural hematomas are common complications of biportal endoscopic decompression.

Complications associated with improper palpation-guided iliac bone marrow biopsy tracts identified on follow-up imaging

Bone marrow biopsy complications are rare. Our aim is to study the association of improper palpation-guided iliac biopsy tract with complications. This is a retrospective study of adult patients who underwent iliac bone marrow biopsy without image guidance at our hospital from January 2019 to January 2021, and have cross-sectional radiologic imaging of the pelvis within 30days following the procedure. Electronic health records were reviewed for clinical data. Two radiologists reviewed images of the pelvis for assessment of biopsy tract and complications. A total of 443 procedures were included in 309 patients, mean age 53.4 ± 18.1years, 112 females (36.2%). In addition, 332 tracts were proper (75%), 97 improper (22%), and 14 unidentified (3%). All 11 complications occurred in procedures with improper tracts; nine bleeding, one fracture, and one facet joint injury. Improper tract was significantly associated with complications (p < .001). There was no statistically significant association between platelet count, international normalized ratio, antiplatelet use and anticoagulant use, and presence of complications (p > .05). Body mass index and subcutaneous fat thickness overlying posterior superior iliac spine were not associated with improper tract (p > .05). Procedures performed by providers with ≤ 12months' experience were significantly associated with improper tract (p < .001) and hence associated with complications (p = .007). Improper tracts were common in palpation-guided iliac bone marrow biopsy and significantly associated with complications. No complications were encountered in proper tract procedures. Procedures performed by providers with ≤ 12months' experience were significantly associated with improper tract and complications.

Comparative Cohort Study for Expansion of Lateral Recess and Facet Joint Injury after Biportal Endoscopic Ipsilateral Decompression and Contralateral Decompression.

Study DesignThis was a retrospective longitudinal study of patients operated on consecutively in a single center from May to October 2019.PurposeThe aim in biportal interlaminar endoscopic decompression surgery for lumbar stenosis is to compare the clinical and radiological outcome of lateral recess decompression and facet preservation, employing ipsilateral (IL) versus contralateral (CL) approaches.Overview of LiteratureThere is scant literature comparing the radiological outcome of lateral recess decompression and facet preservation via IL versus CL approaches in patients undergoing biportal interlaminar endoscopic decompression surgery.MethodsIn this retrospective study, we reviewed 37 IL and 34 CL approaches. Postoperative magnetic resonance imaging of the segment involved was carried out on the same day as the operation for comparison with preoperative imaging. Radiological assessments of recess angle, recess height, facet length, and recess dural sac diameters were compared. In addition, pre- and postoperative Visual Analog Scale (VAS) pain scores for the lower limb were analyzed.ResultsFor IL versus CL approaches, we observed statistical differences in the postoperative recess angle (36.0° vs. 43.7°), recess height (4.27 vs. 5.06 mm), and the dural sac expansion ratio for recess diameter (1.54 vs. 2.17). There was better preservation of facet length in the CL approach than in the IL approach (91.9% vs. 83.7%). There was no difference in VAS improvement between the groups (69.3% vs. 63.6%).ConclusionsUnilateral biportal decompression via the CL interlaminar approach may offer better lateral recess clearance and facet preservation than can be achieved via the IL approach. Larger-scale studies are needed for better delineation and for correlation of radiological features with clinical manifestations.

P20. Predisposing risk factors of the facet joint violation in the lumbar spinal fusion during the instrumentation of minimal invasive spinal surgery

<h3>BACKGROUND CONTEXT</h3> Trending of minimal invasive surgery is increased and adjacent segmental degeneration is the one of the complications sequentially from the procedures which the facet joint injury is one of the causes. The patients who have ASD have vary symptoms such as back pain, neurological compression and instability and some of them required the second or third operation. The facet joint violation can occur during the instrumentation which the surgeons had known the facet joint indirectly visualization. Risk factors of the facet joint violation have the many considerations such as the patient characteristics, facet anatomy, surgical techniques and radiographic assisted. <h3>PURPOSE</h3> Identify the risk factors which have affected the facet joint violation during the minimal invasive spinal surgery. <h3>STUDY DESIGN/SETTING</h3> Retrospective study which is an analysis of 119 patients who have had the minimal invasive spinal surgery from June 2018 to December 2019. <h3>PATIENT SAMPLE</h3> A total of 119 patients who have had the minimal invasive lumbar spinal surgery with percutaneous pedicular screw placed from June 2018 to December 2019. All patients had the CT and MRI scan postoperatively within 6 months after the operation will include to our study. <h3>OUTCOME MEASURES</h3> Facet joint violation at the uppermost level was examined by the CT scan in all dimensions. The facet joint violation defined as the instrument was breeched into the facet joint. We classified these findings as in the facet violation group. The none violation was classified into non-facet violation group. Radiographic parameters (Facet diameter, facet angle, pedicle angle, screw-facet angle, screw-endplate angle and distance between head of screws and facet) were measured. BMI, age, diagnosis and navigation-assisted were included. Risk factor were analyzed and determined which factor have had an effect to the facet joint violation and scoring system for the risk factor was calculated. <h3>METHODS</h3> This study is an analysis of 119 patients who have had the minimal invasive spinal surgery from June 2018 to December 2019. Facet joint violation at the uppermost level was examined by the CT scan in all dimensions. Radiographic parameters (Facet diameter, facet angle, pedicle angle, screw-facet angle, screw-endplate angle and distance between head of screws and facet) were measured. BMI, age, diagnosis and navigation-assisted were included. Risk factor were analyzed and determined which factor have had an effect to the facet joint violation and scoring system for the risk factor was calculated. <h3>RESULTS</h3> A total of 119 patients, 36 males and 83 females, patients mean age was 63 years old, diagnosis was 38 patients had SCS, 54 patients had spondylolisthesis, 17 had HNP, 4 had degenerative scoliosis and 6 had degenerative disc disease. Facet violation was determined 1 patient at L1, 3 patients at L2, 20 patients at L3, 79 patients at L4 and 16 patients at L5. Facet joint violation occurred in 13/119(10.9%) and 15/238(6.3%) joints. No facet joint violation occurred in 60 patients who navigation-assisted was used, versus 15/178(8.4%) joints where there was no navigation(P=0.01). We found an increasing proportion of violations as the lumbar level increased: no violations occurred in 8 patients with lumbar at L1 or L2, 1/40(2.5%), 7/158(4.4%) and 7/32 (21.9%) of violations occurred at L3, L4 and L5, respectively (P=0.01). Although it was not statistically significant, the percentage of violations was higher in patients with scoliosis (12.5%) and DDD (16.7%). Diameter of facet in axial cut, facet angle, screw facet angle and distance between head of screw and facet was statistically significant to determine increasing rate of facet joint violations after multivariable analysis was done (AROC=0.9486, P≤0.05). <h3>CONCLUSIONS</h3> Increasing of the facet diameter in axial plane, facet angle, screw facet angle and distance between dome of screw and facet are one of the risk factor of facet joint violation. Surgeon can avoid the violation when the radiographic consideration was done. Careful screw placement and make the good entry points for instrumentation will decrease rate of facet violation. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Cranial facet joint injuries in percutaneous lumbar pedicle screw placement: a matched-pair analysis comparing intraoperative 3D navigation and conventional fluoroscopy

PurposeThe violation of the cranial adjacent facet is a frequent complication in lumbar instrumentations and can induce local pain and adjacent segment disease. Minimally invasive screw implantation is often stated as risk factor in comparison with open approaches. Percutaneous pedicle screw placement (PPSP) can be performed using single X-ray images (fluoroscopy) or intraoperative 3D navigation. The study compares top-level screws in percutaneous lumbar instrumentations regarding facet violations and screw pedicle position using navigation or fluoroscopy.MethodsPatients after lumbar PPSP were retrospectively separated according to the intraoperative technique: navigation (NAV) or fluoroscopy (FLUORO). Two blinded investigators graded the top-level screws regarding facet violations and pedicle breach in postoperative CT scans. Subsequent matched cohort analysis was performed for comparable groups.ResultsEvaluating 768 screws, we assessed 70 (9.1%) facet violations. Overall, 186 (24.2%) screws were implanted using navigation. There was no significant difference in the rate of facet violations between both imaging groups (NAV 19/186, 10.2%, FLUORO 51/582, 8.8%, p = 0.55). Totally, 728 (94.8%) of all screws showed a correct pedicle position. Most of the 40 unfavorable pedicle positions were placed by fluoroscopy (NAV 4/186, 2.2%, FLUORO 36/582, 6.6%, p = 0.03). The matched cohorts verified these results (facet violations: NAV 19/186, 10.2%, FLUORO 18/186, 9.7%, p = 0.55; pedicle penetrations: NAV 4/186, 2.2%, FLUORO 12/186, 6.9%, p = 0.04).ConclusionsBoth intraoperative imaging techniques allow lumbar PPSP with low rates of cranial facet violations if the surgeon intends to preserve facet integrity. Navigation was superior concerning accurate pedicle screw position, but could not significantly prevent facet violations.

Facet joint osteoarthritis as a component of non-specific low back pain

Back pain is a significant sociomedical problem due to its high prevalence and negative impact on quality of life. According to the latest data, the pain persists in a considerable number of patients for a year or even several years after its onset, which necessitates the search for a cause of the pain syndrome. The facet syndrome induces pain in 15–66% of cases and is most often due to facet joint osteoarthritis. A comprehensive clinical and diagnostic examination helps one to identify facet joint injury; and targeted pathogenetic and multimodal therapy, including non-steroidal anti-inflammatory drugs, provides complete pain relief in most cases and slows the progression of the disease.

Treatment of Injuries to the Subaxial Cervical Spine: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU).

Study Design:Expert consensus.Objectives:To establish treatment recommendations for subaxial cervical spine injuries based on current literature and the knowledge of the Spine Section of the German Society for Orthopaedics and Trauma.Methods:This recommendation summarizes the knowledge of the Spine Section of the German Society for Orthopaedics and Trauma.Results:Therapeutic goals are a stable, painless cervical spine and protection against secondary neurologic damage while retaining maximum possible motion and spinal profile. The AOSpine classification for subaxial cervical injuries is recommended. The Canadian C-Spine Rule is recommended to decide on the need for imaging. Computed tomography is the favoured modality. Conventional x-ray is preserved for cases lacking a “dangerous mechanism of injury.” Magnetic resonance imaging is recommended in case of unexplained neurologic deficit, prior to closed reduction and to exclude disco-ligamentous injuries. Computed tomography angiography is recommended in high-grade facet joint injuries or in the presence of vertebra-basilar symptoms. A0-, A1- and A2-injuries are treated conservatively, but have to be monitored for progressive kyphosis. A3 injuries are operated in the majority of cases. A4- and B- and C-type injuries are treated surgically. Most injuries can be treated with anterior plate stabilization and interbody support; A4 fractures need vertebral body replacement. In certain cases, additive or pure posterior instrumentation is needed. Usually, lateral mass screws suffice. A navigation system is advised for pedicle screws from C3 to C6.Conclusions:These recommendations provide a framework for the treatment of subaxial cervical spine Injuries. They give advice about diagnostic measures and the therapeutic strategy.

Wednesday, September 26, 2018 1:00 PM – 2:00 PM What's New in MIS: 37. Transforaminal percutaneous endoscopic lumbar discectomy for upward migration of upper lumbar foraminal discherniation: clinical and radiological outcomes and technical considerations

PURPOSE Upper lumbar disc herniations occur from the L1-2 to L3-4 level. Compared with lower lumbar disc herniation, conventional open microdiscectomy for upward migration of upper lumbar foraminal disc herniation is associated with a higher risk of isthmic injury and wide facetectomy, which can consequently result in postoperative back pain and segmental instability. To date, there are no published studies on the feasibility of percutaneous endoscopic lumbar discectomy (PELD) for upward migrated foraminal disc herniation of upper lumbar; hence, the purpose of this study was to assess the clinical and radiologicoutcomes and the technical pitfalls of PELD for upper lumbar foraminal disc herniation with upward migration. METHODS Twenty-five patients with upward migrated foraminal disc herniation at the L1-2, L2-3, and L3-4 levels who were treated by PELD under epidural anesthesia were enrolled in this study. The clinical outcomes were assessed using the Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) of pain, and any complications related to the operation were analyzed. Moreover, the radiological outcomes were investigated using postoperative magnetic resonance imaging (MRI) and plain radiography. According to the preoperative sagittal magnetic resonance images, disc upward migration was classified into three zones (A, B, and C) according to the pedicle and vertebral endplates. Zones A and B were defined as the area from the lower margin of the pedicle to the lower endplate, with zone B comprising the upper half and zone A, the lower half. Zone C was defined as the area above the lower margin of the pedicle. We compared the postoperative results according to these disc migration zones. RESULTS All patients were followed for more than 2 years. The mean age was 51.1±14.9 years. Disc migrations were localized in zones A, B, and C in 13, six and six patients, respectively. After PELD, the ODI and VAS score significantly decreased from 69.8±6.5 and 8.1±0.7 to 17.5±4.4 and 2.0±0.7, respectively regardless of the disc migration zones. In 23(92%) out of the 25 patients, the ruptured disc particles were completely removed, as confirmed by postoperative MRI. In zone C, which was defined as disc migration above the lower margin of pedicle, a small remnant disc particle was detected in two patients. However, even in these two patients, the symptoms were improved after PELD. Early recurrence of the herniated disc occurred at the operated segment in one patient with a zone C migration disc. In all patients, the disc height and lordosis were well maintained at the latest follow-up. There were no significant complications related to PELD, except transient numbness and a tingling sensation in the leg in three patients. CONCLUSIONS PELD is a safe and effective treatment option for upward migrated foraminal disc herniation of the upper lumbar area. From anatomical aspect, it is associated with a relatively wide foramen as well as a lower incidence of spinal stenosis. In addition, our results suggest that PELD may prevent complications related to general endotracheal anesthesia and iatrogenic isthmic fracture, violation of facet joint and cauda equina injury. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Correlation of Interpedicular Distance with Radiographic Parameters, Neurologic Deficit, and Posterior Structures Injury in Thoracolumbar Burst Fractures

To correlate interpedicular distance (IPD) with radiographic parameters, neurologic deficit, and posterior structures injury in patients with thoracolumbar burst fractures. A total of 103 patients with a thoracolumbar burst fracture retrospectively reviewed. IPD was measured from the medial sclerotic areas of the pedicles on anteroposterior plain radiographs. Data on local kyphosis (LK), the ratio of anterior to posterior vertebral height (A/P ratio), loss of vertebral body height (LOVBH), spinal canal stenosis (SCS), neurologic status, and injuries to posterior structures (lamina, posterior ligamentous complex, and facet joint) were correlated with IPD using correlation analysis. Logistic regression analysis was used to determine the threshold of IPD predictive of neurologic deficit and posterior structure injury. Of the 103 patients, 98 (95.15%) presented with increased IPD, ranging from 1.41% to 41.53% (mean, 10.92 ± 3.37%). Regarding radiographic parameters, both LK and SCS were linearly correlated with IPD. There was a significant correlation between IPD and neurologic status; logistic regression analysis identified an IPD increase of >20% as an indicator of neurologic deficit. In addition, both facet joint injury and lamina fracture were associated with IPD, with an IPD increase >15% as an indicator of facet joint injury and an IPD increase >20% a predictor of lamina fracture. Our results indicate that IPD is correlated with LK, SCS, neurologic status, facet joint injury, and lamina fracture. Our data demonstrate that IPD measured from plain radiographs is a reliable indicator for assessment of thoracolumbar burst fractures.

Ablation of IB4 non-peptidergic afferents in the rat facet joint prevents injury-induced pain and thalamic hyperexcitability via supraspinal glutamate transporters.

The facet joint is a common source of neck pain, particularly after excessive stretch of its capsular ligament. Peptidergic afferents have been shown to have an important role in the development and maintenance of mechanical hyperalgesia, dysregulated nociceptive signaling, and spinal hyperexcitability that develop after mechanical injury to the facet joint. However, the role of non-peptidergic isolectin-B4 (IB4) cells in mediating joint pain is unknown. Isolectin-B4 saporin (IB4-SAP) was injected into the facet joint to ablate non-peptidergic cells, and the facet joint later underwent a ligament stretch known to induce pain. Behavioral sensitivity, thalamic glutamate transporter expression, and thalamic hyperexcitability were evaluated up to and at day 7. Administering IB4-SAP prior to a painful injury prevented the development of mechanical hyperalgesia that is typically present. Intra-articular IB4-SAP also prevented the upregulation of the glutamate transporters GLT-1 and EAAC1 in the ventral posterolateral nucleus of the thalamus and reduced thalamic neuronal hyperexcitability at day 7. These findings suggest that a painful facet injury induces changes extending to supraspinal structures and that IB4-positive afferents in the facet joint may be critical for the development and maintenance of sensitization in the thalamus after a painful facet joint injury.

Painful Cervical Facet Joint Injury Is Accompanied by Changes in the Number of Excitatory and Inhibitory Synapses in the Superficial Dorsal Horn That Differentially Relate to Local Tissue Injury Severity.

Immunohistochemistry labeled pre- and postsynaptic structural markers to quantify excitatory and inhibitory synapses in the spinal superficial dorsal horn at 14 days after painful facet joint injury in the rat. The objective of this study was to investigate the relationship between pain and synapse density in the spinal cord after facet injury. Neck pain is a major contributor to disability and often becomes chronic. The cervical facet joints are susceptible to loading-induced painful injury, initiating spinal central sensitization responses. Although excitatory synapse plasticity has been reported in the superficial dorsal horn early after painful facet injury, whether excitatory and/or inhibitory synapse density is altered at a time when pain is maintained is unknown. Rats underwent either a painful C6/C7 facet joint distraction or sham surgery. Mechanical hyperalgesia was measured and immunohistochemistry techniques for synapse quantification were used to quantify excitatory and inhibitory synapse densities in the superficial dorsal horn at day 14. Logarithmic correlation analyses evaluated whether the severity of facet injury correlated with either behavioral or synaptic outcomes. Facet joint injury induces pain that is sustained until day 14 (P <0.001) and both significantly greater excitatory synapse density (P = 0.042) and lower inhibitory synapse density (P = 0.0029) in the superficial dorsal horn at day 14. Injury severity is significantly correlated with pain at days 1 (P = 0.0011) and 14 (P = 0.0002), but only with inhibitory, not excitatory, synapse density (P = 0.0025) at day 14. This study demonstrates a role for structural plasticity in both excitatory and inhibitory synapses in the maintenance of facet-mediated joint pain, and that altered inhibitory, but not excitatory, synapse density correlates to the severity of painful joint injury. Understanding the functional consequences of this spinal structural plasticity is critical to elucidate mechanisms of chronic joint pain. N /A.

Spinal Astrocytic Thrombospondin-4 Induced by Excitatory Neuronal Signaling Mediates Pain After Facet Capsule Injury.

Thrombospondin-4 (TSP4) is a synaptogenic molecule that is upregulated in the spinal cord after painful facet joint injury and may contribute to spinal hyperexcitability. However, the mechanisms leading to increased spinal TSP4 are unclear. Because primary afferent activity is critical in the development of spinal hyperexcitability after facet joint injury, this study evaluated the role of afferent firing in the increase of spinal TSP4 and excitatory synapses. Intra-articular bupivacaine was administered immediately or 4days after painful facet joint injury in male Holtzman rats, and TSP4 and excitatory synapses were quantified in the spinal cord at day 7. Immediate, but not delayed bupivacaine treatment, prevents the injury-induced increase in TSP4 and excitatory synapses in the dorsal horn (p<0.0001). Preliminary in vitro experiments suggest that the excitatory signaling molecules ATP and glutamate may stimulate astrocytic TSP4 expression (p≤0.04). Collectively, these results suggest that afferent activity early after facet joint injury is critical for the induction of spinal TSP4. This study advances the understanding of the timing and role of afferent activity in TSP4 expression after injury, which is critical for the therapeutic targeting of TSP4 to treat persistent pain conditions.

Pain from intra-articular NGF or joint injury in the rat requires contributions from peptidergic joint afferents

Non-physiological stretch of the cervical facet joint’s capsular ligament induces persistent behavioral hypersensitivity and spinal neuronal hyperexcitability via an intra-articular NGF-dependent mechanism. Although that ligament is innervated by nociceptors, it is unknown if a subpopulation is exclusively responsible for the behavioral and spinal neuronal responses to intra-articular NGF and/or facet joint injury. This study ablated joint afferents using the neurotoxin saporin targeted to neurons involved in either peptidergic ([Sar9,Met (O2)11]-substance P-saporin (SSP-Sap)) or non-peptidergic (isolectin B4-saporin (IB4-Sap)) signaling to investigate the contributions of those neuronal populations to facet-mediated pain. SSP-Sap, but not IB4-Sap, injected into the bilateral C6/C7 facet joints 14 days prior to an intra- articular NGF injection prevents NGF-induced mechanical and thermal hypersensitivity in the forepaws. Similarly, only SSP- Sap prevents the increase in mechanical forepaw stimulation- induced firing of spinal neurons after intra-articular NGF. In addition, intra-articular SSP-Sap prevents both behavioral hypersensitivity and upregulation of NGF in the dorsal root ganglion after a facet joint distraction that normally induces pain. These findings collectively suggest that disruption of peptidergic signaling within the joint may be a potential treatment for facet pain, as well as other painful joint conditions associated with elevated NGF, such as osteoarthritis.

Detecting Facet Joint and Lateral Mass Injuries of the Subaxial Cervical Spine in Major Trauma Patients.

Study DesignRadiologic imaging measurement study.PurposeTo assess the accuracy of detecting lateral mass and facet joint injuries of the subaxial cervical spine on plain radiographs using computed tomography (CT) scan images as a reference standard; and the integrity of morphological landmarks of the lateral mass and facet joints of the subaxial cervical spine.Overview of LiteratureInjuries of lateral mass and facet joints potentially lead to an unstable subaxial cervical spine and concomitant neurological sequelae. However, no study has evaluated the accuracy of detecting specific facet joint injuries.MethodsEight spinal surgeons scored four sets of the same, randomly re-ordered, 30 cases with and without facet joint injuries of the subaxial cervical spine. Two surveys included conventional plain radiographs series (test) and another two surveys included CT scan images (reference). Facet joint injury characteristics were assessed for accuracy and reliability. Raw agreement, Fleiss kappa, Cohen's kappa and intraclass correlation coefficient statistics were used for reliability analysis. Majority rules were used for accuracy analysis.ResultsOf the 21 facet joint injuries discerned on CT scan images, 10 were detected in both plain radiograph surveys (sensitivity, 0.48; 95% confidence interval [CI], 0.26-0.70). There were no false positive facet joint injuries in either of the first two X-ray surveys (specificity, 1.0; 95% CI, 0.63-1.0). Five of the 11 cases with missed injuries had an injury below the lowest visible articulating level on radiographs. CT scan images resulted in superior inter- and intra-rater agreement values for assessing morphologic injury characteristics of facet joint injuries.ConclusionsPlain radiographs are not accurate, nor reliable for the assessment of facet joint injuries of the subaxial cervical spine. CT scans offer reliable diagnostic information required for the detection and treatment planning of facet joint injuries.