Spinal Facet Research Articles

Update on Interventional Radiology of the Spine.

Interventional radiologists now perform spinal interventions routinely for diagnostic and therapeutic purposes. New technologies for the management of spine pathologies have emerged with promising results in terms of safety and efficacy. Interventional radiology techniques in the spine include percutaneous biopsy and therapies for intervertebral disk herniation or spinal stenosis, facet and sacroiliac joint pathologies, vertebral and sacral fractures, and metastases. These techniques can also be easily combined one with the other or to further therapeutic approaches including systemic therapies, surgical approaches, and radiotherapy. This review provides a comprehensive overview of current percutaneous imaging-guided interventional radiology techniques in the spine. It will help readers become familiar with the most common indications, learn about different technical considerations during performance, and review the available evidence. Controversies concerning new products and technical approaches are also addressed.

Association of presurgical circulating MicroRNAs with 1-year postsurgical pain reduction in spine facet osteoarthritis patients with lumbar spinal stenosis

PurposeUp to 30% of spine facet osteoarthritis patients with lumbar spinal stenosis (SF-OA ​+ ​LSS) have little to no improvement in their pain after surgery. Lack of meaningful improvement in pain following surgery provides a unique opportunity to identify specific predictive biomarker signatures that might be associated with the outcomes of surgical treatment. The objective of the present study was to determine whether a microRNA (miRNA) biomarker signature could be identified in presurgical blood plasma that corresponded with levels of SF-OA ​+ ​LSS patient post-surgical pain intensity one year later. MethodsRNA was extracted from baseline plasma of SF-OA ​+ ​LSS patients and prepared for miRNA sequencing. Statistical approaches were performed to identify differentially expressed miRNAs associated with reduced 1-year postsurgical pain (n ​= ​56). Using an integrated computational approach, we further created predicted gene and pathway networks for each identified miRNA. ResultsWe identified a panel of 4 circulating candidate miRNAs (hsa-miR-155-5p, hsa-let-7e-5p, hsa-miR-125a-5p, hsa-miR-99b-5p) with higher levels at presurgical baseline that were associated with greater changes in % NPRS20Δ, reflecting reduced pain intensity levels at one year. Genes encoding hsa-let-7e-5p, hsa-miR-125a-5p, and hsa-miR-99b-5p are part of an evolutionarily conserved miRNA cluster. Using integrated computational analyses, we showed that mammalian target of rapamycin, transforming growth factor-β1 receptor, Wnt signaling, epithelial–mesenchymal transition regulators, and cholecystokinin signaling were enriched pathways of predicted gene targets. ConclusionsTaken together, our findings suggest that 4 presurgical baseline circulating miRNAs correlate with 1-year postsurgical SF-OA ​+ ​LSS patient pain intensity and represent possible candidate biomarker signature of surgical pain response.

The surgical treatment of subaxial acute cervical spine facet dislocations in adults: a systematic review and meta-analysis.

Adult cervical spine traumatic facet joint dislocations occur when excessive traumatic forces displace the vertebrae's facets, leading to loss of joint congruence. Reduction requires either cranial traction or open surgical procedures. This study aims to appraise the effects of different surgical techniques in the treatment of subaxial cervical spine acute traumatic facet blocks in adults. This study was based on a systematic literature review and meta-analysis, registered in Prospero (CRD42021279249). The PICO question was composed of adults with acute cervical spine traumatic facet dislocations submitted to anterior or posterior surgical approaches, associated or not with cranial traction for reduction. Each surgical technique was compared to the other. The primary clinical outcomes included neurological improvement or worsening and surgical success/failure rates. The anterior approach without cranial traction was efficient in reducing facet displacements. Skull traction was an efficient and immediate method to achieve spine dislocation reductions. Differences were not present among techniques regarding neurological improvement. There were no surgical failures in patients operated on via the posterior approach. The need to decompress and stabilize the cervical spine can be achieved by anterior or posterior surgical approaches, and there is no clear answer as to which initial approach is superior to the other.

A novel use of cone beam CT: flexion and extension weight-bearing imaging to assess spinal stability

To assess spinal stability in different physiological positions whilst weight-bearing. A cone beam CT scanner (CBCT) was used to identify any abnormal motion in the spine in different physiological positions whilst weight-bearing. The lumbar spine was assessed in 6 different patients with a comfortable neutral standing position and standing flexion and extension images in selected patients. Seated, weight-bearing flexion and extension images of the cervical spine were obtained in a further patient. Clinical indications included stability assessment post-trauma, post-surgical fusion and back pain. The projection images were reconstructed using bone and soft tissue algorithms to give isotropic CT images which could be viewed as per conventional multi-detector CT images. The flexion and extension CBCT data were fused to give a representation of any spinal movement between the extremes of motion. The flexion and extension weight-bearing images gave anatomical detail of the spine. Detail of the surgical constructs was possible. Dynamic structural information about spinal alignment, facet joints, exit foramina and paraspinal musculature was possible. The effective dose from the neutral position was equal to that of supine, multi-detector CT. CBCT can be used to image the lumbar and cervical spine in physiological weight-bearing positions and at different extremes of spinal motion. This novel application of an existing technology can be used to aid surgical decision making to assess spinal stability and to investigate occult back and leg pain. Its use should be limited to specific clinical indications, given the relatively high radiation dose.

Increased vertebral body area, disc and facet joint degeneration throughout the lumbar spine in patients with lumbosacral transitional vertebrae.

Lumbosacral transitional vertebrae (LSTV), developmental spinal canal stenosis, lumbar disc and facet joint degeneration are all common lumbar spine conditions. This study explores the relationship between these entities. Five hundred and five patients (254 females, 251 males), mean age 57 ± 13 years, who underwent abdominopelvic CT examinations were studied. Vertebral body cross-sectional area (CSA), spinal canal CSA, width and depth were measured from L1 to L5. The presence of LSTV was documented and the severity of disc/facet joint degeneration graded. LSTV was present in 155 (31%) of 505 patients, being twice as common in males than in females. After controlling for age, height and weight, vertebral body CSAs from L1 to L5 in male LSTV patients were, on average, 9.8% larger than those in male non-LSTV patients (p < 0.0001 for all) while vertebral body areas at L3 and L4 were 4.5% larger in female LSTV patients than in non-LSTV female patients. Disc degeneration from L2/3 to L5/S1 and facet joint degeneration from L2/3 to L4/5 were more severe in LSTV patients. LSTV Castellvi Type II patients appear to be most prone to disc and facet degeneration. LSTV patients, and particularly male patients, have an increased vertebral body CSA compared to non-LSTV patients throughout the lumbar spine. LSTV patients also have more severe disc and facet joint degeneration. The increase in vertebral body area may be contributing to the increased lumbar and facet joint degeneration seen in LSTV patients. • LSTV patients have increased vertebral body cross-sectional area throughout their lumbar spine compared to non-LSTV patients. This vertebral body area increase was more pronounced in male patients and also apparent in younger patients with LSTV. • LSTV patients have increased disc and facet joint degeneration affecting most of the lumbar spine than non-LSTV patients. • Increased vertebral body area may contribute to the increased lumbar disc and facet joint degeneration seen in LSTV patients.

Acute development of spinal lumbar synovial facet cyst within 1 week after lumbar decompression: illustrative case

BACKGROUNDSynovial facet cysts can sometimes develop in patients with lumbar spinal stenosis after decompressive laminectomy. The etiology of spinal lumbar synovial cysts is still unclear, but their formation is associated with underlying spinal instability, facet joint arthropathy, and degenerative spondylolisthesis.OBSERVATIONSA 61-year-old-male patient presented with neurogenic claudication due to lumbar spinal stenosis. Radiographic studies showed grade I spondylolisthesis and radiological predictors of delayed spinal instability. He underwent lumbar decompression and shortly thereafter developed spinal instability and recurrent symptoms, with formation of a new spinal lumbar synovial facet cyst. He required revisional decompression, cyst excision, and posterolateral spinal fusion for definitive treatment.LESSONSThe literature reports postoperative spinal instability in up to one-third of patients with lumbar spinal stenosis and stable degenerative spondylolisthesis who undergo decompressive laminectomy. Close radiographic monitoring and early advanced imaging may be prudent in this patient population if they develop new postoperative neurological symptoms and show radiographic predictors of instability on preoperative imaging. Posterolateral spinal fusion with instrumentation should be considered in addition to lumbar decompression in this select group of patients who demonstrate radiographic predictors of delayed spinal instability if they are medically capable of tolerating a spinal fusion procedure.

ASSOCIATION OF PRESURGICAL CIRCULATING MICRORNAS WITH 1-YEAR POSTSURGICAL PAIN REDUCTION IN SPINE FACET OSTEOARTHRITIS PATIENTS WITH LUMBAR SPINAL STENOSIS

Purpose: In any given year, low back pain (LBP) affects many adults around the world and generates tremendous personal and societal burden. Among patients referred from primary care with persistent LBP, 41% have a clinical profile and symptoms consistent with spine facet osteoarthritis-induced lumbar spinal stenosis (S-FOA+LSS). S-FOA+LSS is the principal cause of chronic back (and leg/neurogenic claudication) pain for 1 in 5 adults over the age of 65, and is the primary reason for spinal surgery in this age group.

Resection of Lumbar Spinal Facet Joint Cysts and Cerebrospinal Fluid Leakage: Incidence, Prognostic Parameters, and Outcome in a Single-center Series.

Single-center series. Intraspinal facet joint cysts can lead to nerve root compression symptoms with severe discomfort and disability. Permanent improvement can be achieved by surgical resection of the cyst. However, cerebrospinal fluid (CSF) leakage is a common problem in resection of facet joint cyst.The aim of the study was to investigate the frequency of CSF leak after resection of a joint cyst and to determine predictive factors. A total of 176 consecutive patients underwent surgery for lumbar spinal facet joint cyst in our institution between 1997 and 2018. Patients with a CSF leak were compared with patients without a CSF leak (control group). CSF leakage occurred in 14 patients (8.0%) In 2 of the cases (14.3%), the CSF leak was recognized only postoperatively, in 12 cases (85.7%), the CSF leak was detected intraoperatively. Despite intraoperative dura repair, 4 of these 12 patients (33.3%) presented with CSF leakage postoperatively. Altogether 6 patients had postoperative CSF leakage. Compared with patients without CSF leak, there were no differences in preoperative symptoms, surgical technique, complications, or postoperative findings. Adhesion of the cyst to the dura mater was present in all 14 patients with CSF leakage (100%), but only 61.7% of the control group ( P <0.005). All patients in the CSF leak group showed an improvement of their preoperative symptoms. The rate of CSF leakage in resection of spinal facet joint cyst was 8% in the present study. The occurrence of a CSF leakage was independent of clinical factors, level, or side of the cyst, but significantly correlated to dural adhesion of the cyst.Since neither clinical recovery nor recurrence rates do depend on complete removal of the cyst, aggressive resection of dural adherend parts of the cyst wall should be avoided to prevent CSF leakage.

Ultrasound-guided interventions in rheumatology.

Over the last few years, percutaneous procedures have undergone great advances, thanks to the ultrasound (US) guidance, due to the technical improvements in the US field, combined with the greater availability, good portability, and reduced cost of US devices. The direct target visualization and the real-time imaging performance enabled by US-guidance account for an improved accuracy in needle placement in several rheumatology interventions. So, ultrasound-guided procedures contribute to several diagnostic or therapeutic procedures such as fluid aspiration or treatment instillations of common joints, tendons, and bursas. In clinical practice, this fact is especially important in the case of depth areas like the hip, small anatomical structures as tendon sheaths or nerves in tenosynovitis or nervous blocks, or complex anatomical structures like the spine's facet joints. The US-guide is an essential tool for performing diagnostic procedures as synovial biopsy. US can also be combined with other imaging techniques, like the establishment portal arthroscopy for instance. Compared to older blind procedures, US-guided injections are more accurate and safer, and they result in better clinical outcomes in terms of joints improvement in function and decreased risk of damages caused by needle misplacement. With the ultrasound guided treatment, we can avoid the instillation of therapeutic products outside the predetermined target, which may be sometimes potentially harmful. The aim of this article is to describe the main generalities of ultrasound-guided procedures in rheumatology, their main advantages and disadvantages, and their particularities in joints where they are most frequently used, such as the shoulder, hip, and knee.

MRI for in vivo Analysis of Ablation Zones Formed by Cooled Radiofrequency Neurotomy to Treat Chronic Joint Pain Across Multiple Axial Spine Sites.

PurposeRadiofrequency (RF) ablation is the targeted damage of neural tissues to disrupt pain transmission in sensory nerves using thermal energy generated in situ by an RF probe. The present study aims to evaluate the utility of magnetic resonance imaging (MRI) for in vivo quantitative assessment of ablation zones in human subjects following cooled radiofrequency neurotomy for chronic pain at spinal facet or sacroiliac joints. Ablation zone size and shape have been shown in animal models to be influenced by size and type of RF probe – with cooled RF probes typically forming larger, more spherical ablation zones. To date, MRI of RF ablation zones in humans has been limited to two single retrospective case reports.Patients and MethodsA prospective, open-label pilot study of MRI for evaluation of cooled radiofrequency ablation zones following standard of care procedures in adult outpatients was conducted. Adult subjects (n=13) received monopolar cooled RF (CRF) ablation (COOLIEF™, Avanos Medical) of sensory nerves at spinal facet or sacroiliac joints, followed by an MRI 2–7 days after the procedure. MRI data were acquired using both Short Tau Inversion Recovery (STIR) and contrast-enhanced T1-weighted (T1C) protocols. T1C MRI was used to calculate 3-dimensional ellipsoid ablation zone volumes (V), where well-defined regions of signal hyperintensity were used to identify three orthogonal diameters (T, D, L) and apply the formula V=π/6×T×D×L.ResultsAmong 13 patients, 96 CRF ablation zones were created at 4 different anatomic sites (sacroiliac, lumbar, thoracic and cervical). CRF ablation zone morphology varied by anatomical location and structural features of surrounding tissues. In some cases, proximity to bone and striations of surrounding musculature obscured ablation zone borders. The volumes of 75 of the 96 ablation zones were measurable from MRI, with values (mean±SD) ranging from 0.4679 (±0.29) cm3 to 2.735 (±2.62) cm3 for the cervical and thoracic sites, respectively.ConclusionIn vivo T1C MRI analysis of cooled RF ablation zones at spinal facet and sacroiliac joints demonstrated variable effects of local tissues on ablation zone morphology. Placement of the CRFA probe very close to bone alters the ablation zone in a negative way, causing non-spherical and incomplete lesioning. These new data may serve to inform practicing physicians about optimal cooled RF probe placement in clinical procedures.

A novel technique for surgical excision of a symptomatic lumbar spine facet joint synovial cyst using a cyst dyeing method: a report of two cases and a literature review

The aim of this study was to investigate the efficacy of a cyst dyeing technique that was used during the surgical excision of facet joint cysts in 2 cases. We evaluated the patients’ clinical outcomes and perioperative complications after decompression of lumbar spinal stenosis caused by the cysts. Two patients, who underwent surgical decompression for symptomatic lumbar spinal stenosis caused by facet cysts in August and October 2020, were reviewed. Their main complaints were severe low back pain and sciatica 1 or 2 months ago, for which they visited Wooridul Spine Hospital, Daegu, Korea. Under general anesthesia, the cysts were removed with the cyst dyeing method, using indigo carmine. Clinical outcomes were assessed by preoperative and postoperative visual analog scale (VAS) scores. Perioperative complications were observed.Favorable clinical outcomes and no perioperative complications were reported. Low back pain and sciatica improved, as shown by changes of the VAS score from 9 or 8 to 1, and no dural defects were observed. The cyst dyeing method is an effective technique for the surgical removal of symptomatic lumbar spine facet joint cysts.

Morphometric Computed Tomography-Based Analysis of Cervical Pedicle and Facet Joints in South Indian Population

Title: Morphometric CT based analysis of cervical pedicle and facet joints in South Indian population.&#x0D; Aim: To evaluate individual morphometric variations of the cervical spine pedicles and facet joints by computed tomography among patients attending a tertiary care centre.&#x0D; Methodology: A retrospective cross-sectional study was carried out among 25 patients undergoing CT study of the cervical spine at Saveetha Medical College and Hospitals, Thandalam. Various measurements of the cervical pedicles and cervical facet joints were obtained and analysed as mean, standard deviation, and range using Statistical Package for the Social Sciencessoftware.&#x0D; Results: Among the 25 subjects, 56% were males and 44% were females with mean age of 59.9 and 55.2 respectively. Pedicle length (PL) and Pedicle height (PH) was comparatively smaller in women than in men. Pedicle isthmus (PI) and Lateral pedicle distance (LPD) of C7 was the greatest in both genders. Pedicle axial length (PAL) was equal in both genders with left side being more than the right. Maximum Superior Pedicle distance (SPD) was found to be at C5 level in both genders. Sagittal angulation showed lesser values in females and the Transverse angulation was the lowest at C7 level in both genders. Facet tropism showed a decreasing pattern from C3 to C7 in both genders.&#x0D; Conclusion: This study helps the surgeon to understand variations in the morphometrics of the study population and will be useful in the determination of a safe treatment modality.

Vertebrae at the thoracolumbar junction: A quantitative assessment using CT scans.

The thoracolumbar junction is often associated with traumatic injuries, due to its biomechanical instability. Reasons for this instability are currently still under debate; however, contributing factors such as the rapid change in spinal curvature and facet orientation from the thoracic to lumbar transition have been implicated. Normally, the superior facet orientation in the thoracic region is angled in a coronal plane, whereas vertebrae in the lumbar region have facets angled in the sagittal plane. Distinguishing between thoracic, lumbar, and transitional vertebrae at the thoracolumbar junction based on articular facet angles, using quantitative methods on CT scans has, to the authors' knowledge, not yet been reported in the literature. Therefore, this study aimed to evaluate whether quantitative measurements can be clinically applied and used to differentiate vertebrae at the thoracolumbar junction using CT scans and, additionally, to record possible cases of congenital defects or variations observed in the spine. A sample (n=173) of CT scans representative of the Windhoek population in Namibia was retrospectively assessed using radio-imaging software. Measurements of the angle formed by the superior facets of the vertebrae at the thoracolumbar junction (T11-L1) were recorded. Based on the results of this study, quantitative morphometry of the superior facet of vertebrae can differentiate between thoracic, lumbar,. and transitional vertebrae at the thoracolumbar junction. All individuals with identified thoracolumbar transitional vertebrae (TLTV) in this sample had at least one other congenital anomaly of the spine.

Extracting cervical spine popping sound during neck movement and analyzing its frequency using wavelet transform

With the excessive use of smartphones, cervical spine pain is becoming increasingly prevalent. A denoised cervical spine popping sound can aid in monitoring and estimating the state of the cervical spine. However, cervical spine popping sounds that are collected when a subject performs neck movements is contaminated by constant noise. Therefore, a denoising algorithm called Wavelet Transform-Based Stationary-Nonstationary (WTST-NST) is adopted to remove the noise. The input signal is decomposed using wavelet transform to obtain the wavelet coefficients. The wavelet coefficients are then separated into two parts, the nonstationary part and the stationary part, using stationary-nonstationary filtering technology. Finally, the wavelet coefficients of the nonstationary part are reconstructed to obtain the denoised cervical spine popping sound. In addition, the frequency components of the sound are analyzed using the multiresolution analysis of the wavelet transform. The experimental results demonstrate that the implementation of the WTST-NST algorithm in the sound analysis of cervical spine facet joints efficiently reduces the overlapped noise, producing an almost pure cervical spine popping sound. Furthermore, the frequency components of cervical spine popping sounds during the smartphone use period are significantly higher than that in the non-use period and are significantly associated with self-reported neck and upper back pain during the smartphone use period. Therefore, the WTST-NST algorithm preserved almost all the features of the sampled input signal. The denoised cervical spine popping sound can be used to quickly and conveniently monitor the status of the cervical spine during the smartphone use period.

Minimally Invasive Surgery for Traumatic High-Grade Lateral Spondylolisthesis of L1 with Multiple Spinal Fractures: Closed Reduction and Internal Fixation Using Percutaneous Pedicle Screws.

Background:Traumatic high grade lateral spondylolisthesis at the thoracolumbar junction is an extremely severe injury caused by high-energy trauma, commonly resulting in polytrauma. The treatment of this pathology is challenging, and even death following surgery has been reported. Therefore, it is necessary to focus on making surgical invasion minimal.Methods:A 53-year-old female fell from a height and presented with severe back pain and complete paralysis below L1. Computed tomography (CT) showed a Grade 4 traumatic lateral spondylolisthesis and severe comminution of L1, and mild compression fractures at T9 and L3.Results:First, we performed posterior surgery on the day of the injury to reduce the fracture and stabilize the spinal column using percutaneous pedicle screws (PPS). Twelve days later we resected the L1 vertebral body and inserted a cage with an iliac bone graft using an anterior approach. The estimated blood loss from posterior and anterior surgeries was 320ml and 200ml, respectively. Bony fusion was achieved as seen on CT at the 1-year follow-up.Conclusion:A 2-stage combined posterior-anterior approach using PPS can be performed less invasively, enabling adequate reduction, internal fixation, and anterior reconstruction for patients with high grade traumatic lateral spondylolisthesis without spinal shortening or facet interlocking.

Estimating Facet Joint Apposition with Specimen-Specific Computer Models of Subaxial Cervical Spine Kinematics.

Computational models of experimental data can provide a noninvasive method to estimate spinal facet joint biomechanics. Existing models typically consider each vertebra as one rigid-body and assume uniform facet cartilage thickness. However, facet deflection occurs during motion, and cervical facet cartilage is nonuniform. Multi rigid-body computational models were used to investigate the effect of specimen-specific cartilage profiles on facet contact area estimates. Twelve C6/C7 segments underwent non-destructive intervertebral motions. Kinematics and facet deflections were measured. Three-dimensional models of the vertebra and cartilage thickness estimates were obtained from pre-test CT data. Motion-capture data was applied to two model types (2RB: C6, C7 vertebrae each one rigid body; 3RB: left and right C6 posterior elements, and C7 vertebrae, each one rigid body) and maximum facet mesh penetration was compared. Constant thickness cartilage (CTC) and spatially-varying thickness cartilage (SVTC) profiles were applied to the facet surfaces of the 3RB model. Cartilage apposition area (CAA) was compared. Linear mixed-effects models were used for all quantitative comparisons. The 3RB model significantly reduced penetrating mesh elements by accounting for facet deflections (p=0.001). The CTC profile resulted in incongruent facet articulation, whereas realistic congruence was observed for the SVTC profile. The SVTC profile demonstrated significantly larger CAA than the CTC model (p<0.001).

Posterior Lumbar Interbody Fusion with Preservation of Posterior Structures for Management of Lumbar Spondylolisthesis

Introduction: Successful posterior lumbar interbody fusion requires excessive removal of posterior spinal elements and distraction of neural structures. It also requires a large amount of bone graft. The authors have developed this technique to assess results of treatment of degenerative spondylolisthesis by posterior lumbar interbody fusion with preservation of posterior spinal elements and also to examine the safety and efficacy of the recapping T-saw laminoplasty technique for the management of degenerative lumbar spondylolisthesis using posterior lumbar interbody fusion by interbody cages with preservation of posterior elements.&#x0D; Methodology: Twenty-five patients with degenerative spondylolisthesis underwent recapping T-saw laminoplasty in the lumbar spine for posterior lumbar interbody fusion with interbody cage. The T-saw was used for the division of the posterior elements. After discectomy and insertion of cages, the excised lamina was replaced exactly in situ to their original anatomic position. Patients were followed neurologically and radiologically.&#x0D; Result: Only one lamina was excised and replaced again. Primary bone healing was obtained in all patients by four to six months post surgery. No complications such as postoperative spinal canal stenosis, facet arthrosis, or kyphosis were observed.&#x0D; Conclusion: This technique of posterior lumbar interbody fusion through recapping laminoplasty provide wide space for easier insertion of cages and allow anatomic reconstruction of the vertebral arch preserving its important mechanical roles.

RETRACTED: Influence of nucleotomy on the load sharing in the spinal facet joint under the loading scenarios of different human postures

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.

POS1150 ANATOMICAL LOCATIONS AND CORRELATES OF CALCIUM PYROPHOSPHATE CRYSTAL DEPOSITS OF THE SPINE – PATHOLOGIC EXAMINATION OF 77 SURGICAL CASES

Background:Spinal involvement in calcium pyrophosphate deposition disease (CPPD) is thought to be a rare occurrence and is seen infrequently as crowned dens syndrome. Furthermore, data on anatomical locations and correlates of calcium pyrophosphate (CPP) deposits in spinal CPPD are scarce.Objectives:To describe the anatomical locations and correlates of pathologically confirmed CPPD of the spine.Methods:Consecutive patients with spinal CPPD were identified via retrospective chart review of individuals who underwent spine surgery for intractable chronic neck or back pain at Massachusetts General Hospital between 2009 and 2014. These deposits and surrounding anatomical structures were surgically resected and confirmed to have calcium pyrophosphate deposition upon pathologic review. We reviewed musculoskeletal imaging (CT, MRI, XR) and laboratory data from these pathologically confirmed cases.Results:From April 2009 to August 2014, we identified 77 individuals with pathologically confirmed CPPD of the spine. The mean age was 68 years; 41 (53%) were female; mean BMI was 28.7. Calcium pyrophosphate (CPP) was grossly identified intraoperatively by the surgeon in 38 cases (50%), typically as “chalky white deposits” (Figure 1). CPP deposits were seen most frequently in the ligamentum flavum (23%) and intervertebral disc (23%), followed by other less common locations (Table 1). Imaging findings in the soft tissue or intervertebral disc suggestive of CPPD were found in 5 cases (6%), whereas findings of spinal canal narrowing, facet arthropathy, or ligamentum flavum thickening were eventually correlative with CPP deposits in pathologic specimens. Only 7 (9%) experienced a prior episode of acute CPP arthritis (pseudogout). Chondrocalcinosis on x-ray was seen in 26 cases (34%), most commonly in the wrist and/or knees. Osteoarthritis was present in all spinal imaging, and 65% had comorbid scoliosis. Laboratory abnormalities associated with secondary causes of CPPD (hypercalcemia, hypomagnesemia, hyperparathyroidism) were not seen with spinal CPPD.Conclusion:Spinal CPPD may occur more frequently than previously perceived. The ligamentum flavum and intervertebral discs were common anatomical locations for spinal CPPD. Advanced imaging of the spine showed low sensitivity for detecting spinal CPPD. Only a small minority had typical peripheral joint involvement or imaging with peripheral joint chondrocalcinosis. Thus, without pathologic confirmation, the vast majority of cases would remain unidentified. These findings call for the need to seek pathologic confirmation to determine the robust epidemiology and also raise the potential role for preoperative CPPD treatment.Table 1.Spinal Anatomic Locations of Pathologically Confirmed CPPDSpinal Anatomic LocationNo. of Sites (%)*ligamentum flavum29 (23)Intervetebral Disc28 (23)Other Location19 (15)Posterior Elements18 (15)Facet14 (11)Synovium8 (6)Interspinous Ligament3 (2)Subarticular/Lateral Recess2 (2)Fibrocartilaginous Tissue1 (1)Inner Spine1 (1)Other Ligament1 (1)*Some patients had more than one anatomic location where CPP was isolatedFigure 1.Gross visualization of calcium pyrophosphate deposition (black arrow)Disclosure of Interests:Jonathan Dau: None declared, Gary Ho: None declared, Hyon Choi Consultant of: Ironwood, Selecta, Horizon, Takeda, Kowa, Vaxart, Grant/research support from: Ironwood, Horizon, Joseph Schwab: None declared, Minna Kohler Speakers bureau: Eli Lily, Consultant of: Novartis.

Variation in global treatment for subaxial cervical spine isolated unilateral facet fractures

PurposeTo determine the variation in the global treatment practices for subaxial unilateral cervical spine facet fractures based on surgeon experience, practice setting, and surgical subspecialty.MethodsA survey was sent to 272 members of the AO Spine Subaxial Injury Classification System Validation Group worldwide. Questions surveyed surgeon preferences with regard to diagnostic work-up and treatment of fracture types F1–F3, according to the AO Spine Subaxial Cervical Spine Injury Classification System, with various associated neurologic injuries.ResultsA total of 161 responses were received. Academic surgeons use the facet portion of the AO Spine classification system less frequently (61.6%) compared to hospital-employed and private practice surgeons (81.1% and 81.8%, respectively) (p = 0.029). The overall consensus was in favor of operative treatment for any facet fracture with radicular symptoms (N2) and for any fractures categorized as F2N2 and above. For F3N0 fractures, significantly less surgeons from Africa/Asia/Middle East (49%) and Europe (59.2%) chose operative treatment than from North/Latin/South America (74.1%) (p = 0.025). For F3N1 fractures, significantly less surgeons from Africa/Asia/Middle East (52%) and Europe (63.3%) recommended operative treatment than from North/Latin/South America (84.5%) (p = 0.001). More than 95% of surgeons included CT in their work-up of facet fractures, regardless of the type. No statistically significant differences were seen in the need for MRI to decide treatment.ConclusionConsiderable agreement exists between surgeon preferences with regard to unilateral facet fracture management with few exceptions. F2N2 fracture subtypes and subtypes with radiculopathy (N2) appear to be the threshold for operative treatment.