Facet Degeneration Research Articles

The role of oblique spinous process abutment in the pathogenesis of degenerative lumbar scoliosis: an in vitro study

PURPOSE: To evaluate the efficacy and utility of SPECT/CT as a diagnostic modality and preoperative planning tool in patients undergoing fusion surgery for low back pain and/or leg pain. STUDY DESIGN/SETTING: A prospective cohort study (n525) performed over a 2-year period. PATIENT SAMPLE: All consecutive patients requiring lumbar spondylodesis for back pain and/or leg pain included. OUTCOME MEASURES: Clinical outcome measures included EQ-5D, EQ-5D VAS, ODI and VAS Pain Scores. METHODS: SPECT/CT fusion imaging was performed in conjunction with standard CT and MRI preoperatively to guide patient selection and surgical planning. Clinical outcome measures were collected preoperatively and at 6 weeks, 6 months and 1 year postoperatively. RESULTS: SPECT/CT fusion imaging demonstrated increased sensitivity for facet degeneration when compared to MRI. No difference was identified when comparing SPECT/CT to standard CT to assess disc degeneration. There was a significant improvement in all clinical outcome measures assessed preoperatively and followed out to 1-year postoperatively. Mean ODI score improved from 58.92 to 12.0; VAS back pain score improved from 7.46 preoperatively to 1.0; VAS leg pain score improved from 4.15 to 0.25. CONCLUSIONS: SPECT/CT fusion imaging is an excellent adjunct to existing imaging modalities, facilitating accurate level selection in patients undergoing lumbar fusion surgery for low back pain and/or leg pain. Lumbar fusion surgery guided by SPECT/CT fusion imaging was associated with excellent postoperative health related quality of life (HRQOL) outcome measures. CONFLICTS OF INTEREST: None. FUNDING SOURCES: None.

Reoperation rate and risk factors of elective spinal surgery for degenerative spondylolisthesis: minimum 5-year follow-up

Background contextThe favorable outcome of surgical treatment for degenerative lumbar spondylolisthesis (DS) is widely recognized, but some patients require reoperation because of complications, such as pseudoarthrosis, persistent pain, infection, and progressive degenerative changes. Among these changes, adjacent segmental disease (ASD) and same segmental disease (SSD) are common reasons for reoperation. However, the relative risks of the various factors and their interactions are unclear. PurposeThe purpose of this study was to determine the longitudinal reoperation rate after surgery for DS and to assess the incidence and independent risk factors for ASD and SSD. Study designThis study is a retrospective consecutive case series of patients with DS who were surgically treated. Patient sampleWe assessed 163 consecutive patients who were surgically treated for DS between 2003 and 2008. Individual patients were followed for at least 5 years after the initial surgery. Outcome measuresThe primary end point was any type of second lumbar surgery. Radiographic measurements and demographic data were reviewed. We compared patients who underwent reoperation with those who did not. Logistic regression analysis was used to determine the relative risk of ASD and SSD in patients surgically treated for DS. MethodsRadiographic measurements and demographic data were reviewed. We identified the incidence and risk factors for reoperation, and we performed univariate and multivariate analyses to determine the independent risk factors for revision surgery for SSD and for ASD as the two distinct reasons for the reoperation. Age, gender, etiology, body mass index (BMI), and other radiographic data were analyzed to determine the risk factors for developing SSD and ASD. ResultsThe average patient age was 65.8 (50–81 years; 73 women and 90 men; mean follow-up, 5.9±1.6 years). Eighty-nine patients had posterior lumbar interbody fusion and 74 had laminotomies. Twenty-two patients had L3–L4 involvement and 141 had L4–L5 involvement. The cumulative reoperation rate was 6.1% at 1 year, 8.5% at 2 years, 15.2% at 3 years, 17.7% at 5 years, and 23.3% (38/163 patients) at the final follow-up. A significantly higher reoperation rate was observed for patients undergoing laminotomy than for patients undergoing posterior lumbar interbody fusion (33.8% vs. 14.4%, p=.01). Eighteen patients (11.0%) had SSD, and 13 patients (8.9%) developed ASD. Higher BMI (obesity) and greater disc height (greater than 10 mm) predicted the occurrence of SSD in the multivariate model (BMI=odds ratio 4.11 [95% confidence interval 1.29–13.11], p=.016; disc height=3.18 [1.03–9.82], p=.044), and gender (male) and facet degeneration (Fujiwara grade greater than 3) predicted the development of ASD in the multivariate model (gender=4.74 [1.09–20.45], p=.037; facet degeneration=6.31 [1.09–36.52], p=.039). ConclusionsThe incidence of reoperation in patients surgically treated for DS was 23.2% at a mean time of 5.9 years. A significantly higher incidence of reoperation was observed in patients treated with decompression alone compared with those treated with decompression and fusion. Body mass index and disc height were identified as independent risk factors for SSD, whereas male gender and facet degeneration were identified as independent risk factors for ASD. The results of this comprehensive review will guide spine surgeons in their preoperative planning and in the surgical management of patients with DS, thereby reducing the reoperation rate.

Radiological and Radionuclide Imaging of Degenerative Disease of the Facet Joints.

The facet joint has been increasingly implicated as a potential source of lower back pain. Diagnosis can be challenging as there is not a direct correlation between facet joint disease and clinical or radiological features. The purpose of this article is to review the diagnosis, treatment, and current imaging modality options in the context of degenerative facet joint disease. We describe each modality in turn with a pictorial review using current evidence. Newer hybrid imaging techniques such as single photon emission computed tomography/computed tomography (SPECT/CT) provide additional information relative to the historic gold standard magnetic resonance imaging. The diagnostic benefits of SPECT/CT include precise localization and characterization of spinal lesions and improved diagnosis for lower back pain. It may have a role in selecting patients for local therapeutic injections, as well as guiding their location with increased precision.

Simple facet joint repair with dynamic pedicular system: Technical note and case series.

Purpose:Facet joints are important anatomical structures for the stability of spine. Surgical or degenerative damage to a facet joint may lead to spinal instability and causes clinical problems. This article explains the importance of facet joints, reviews facet replacement systems, and describes a simple and effective method for facet replacement after surgical removal of facet joints.Materials and Methods:Ten patients were operated with the diagnosis of unilateral nerve root compression secondary to facet degeneration. The hypertrophic facet joints were removed with microsurgical techniques and the roots were decompressed. Then, a unilateral artificial facet joint was created using two hinged screws and a dynamic rod.Results:The clinical outcome of all the patients was determined good or excellent at second and last follow-up (mean 13.3 months) controls using visual analog scale (VAS) and Oswestry Disability Index (ODI) scores. Radiological evaluations also demonstrated no implant-related complications.Conclusions:The authors suggest that, if removal of a facet joint is necessary to decompress the nerve roots, the joint can be replaced by a construct composed of two hinged screws connected by a dynamic rod. This simple system mimics the function of a normal facet joint and is an effective technique for unilateral facet joint replacement.

Controlled motion with the XL-TDR lateral-approach lumbar total disk replacement: in vitro kinematic investigation.

Anterior-approach total disk replacement (TDR) devices are thought to retain close to so-called normal range of motion (ROM); however, they are also inherently unstable due to resection of the anterior longitudinal ligament and annulus. This instability/laxity is manifested as increased neutral zone (NZ) motion. The XL-TDR device (NuVasive, Inc., San Diego, California, United States) is implanted through a lateral approach that preserves the anterior ligamentous and annular structures. This potentially makes the XL-TDR device more stable than those delivered anteriorly. This study investigates XL-TDR biomechanical features in a cadaveric model. Biomechanical evaluation consisting of nondestructive multidirectional testing was performed with the hybrid protocol on six fresh-frozen cadaveric specimens (L2-S1). Motion segment kinematics were obtained using an optoelectronic system. Test conditions were (1) intact spine, (2) XL-TDR at L4-L5, and (3) XL-TDR at L4-L5 with anterior annulus/ligament resected. ROM and NZ were calculated for each condition in each loading direction (flexion-extension total, flexion alone, extension alone, lateral bending, and axial rotation). Insertion of the XL-TDR device decreased ROM with respect to intact in all directions. NZ in all directions was not statistically different from intact (p < 0.05), although there was a trend toward decreased NZ in flexion (p = 0.078). Removing the anterior ligament/annulus increased ROM significantly with respect to the XL-TDR condition in all directions (p < 0.003). NZ also increased, with the most significant changes in extension, lateral bending, and axial rotation (p < 0.002). The kinematics of XL-TDR have demonstrated that the retention of the anterior ligament/annulus has a significant stabilizing effect, diminishing ROM to less than intact, with a more controlled motion (more natural NZ). Removing the anterior ligament/annulus illustrated its stabilizing role, with ROM and NZ increasing significantly. Future studies will investigate the potential benefit of controlled XL-TDR motion on facet kinematics that may have clinical implications related to limiting facet degeneration.

The influence of intrinsic disc degeneration of the adjacent segments on its stress distribution after one-level lumbar fusion.

The presence of degeneration alters the stress within that particular degenerated disc. Therefore, the state of degeneration of the disc at the level adjacent to a single level fusion would influence the rate of subsequent further degeneration of that same adjacent disc. Therefore, the purpose of this study was to investigate the biomechanical effect of the disc degeneration at the adjacent segment on the stress of the corresponding segment after one segment lumbar fusion using validated finite element (FE) models. Three validated L2-L5 FE models with different grades of disc degeneration (normal, mild, moderate) at the L2-L5 were simulated. Based on the intact models that represented each grade of disc degeneration, the matched L3-L4 instrumented fusion models were developed. Therefore, three intact models and three matched fusion models were simulated. Under the 400-N pre-compressive follower loading, 7.5 Nm moments simulating flexion, extension, lateral bending, and torsion in five steps were imposed on the L2 superior endplate of three intact models. The hybrid loading protocol was utilized for the fusion models. The intradiscal pressure and the maximal von Mises stress of the annulus fibrosus in the L2-L3 and L4-L5 segments were analyzed and compared between fusion and intact models with each grade of disc degeneration. Disc degeneration led to an increase of maximal von Mises stress of annulus fibrosus at this degenerated disc, related to disc degeneration under flexion, extension, lateral bending and torsion moments. Furthermore, the fusion also increased a maximal von Mises stress of annulus fibrous at both proximal and distal adjacent segments under hybrid protocol. The increases of annular stress were greater at the proximal adjacent segment than those at distal adjacent segment. However, the contribution of the fusion surgery to the increment rate of annulus fibrosus stress at the adjacent segment did not increase in relation with disc degeneration states at the adjacent segment. The present study demonstrates disc degeneration per se and fusion can cause the increase of disc stress at the adjacent segment. However, they seem not to act synergistically. Therefore, the proper decision of fusion extent needs comprehensive individual considerations about the degree of facet degeneration, canal stenosis and patient's activity.

Effect of pulsed radiofrequency in treatment of facet-joint origin back pain in patients with degenerative spondylolisthesis

Degenerative spondylolisthesis is a well-recognized source of low back pain mainly induced by facet joint pain. Pulsed radiofrequency (PRF) allows heat dissipation, thus producing a temporary injury that affects only type C fibers responsible for pain conduction. We attempted to test whether PRF is a better choice for facet pain due to spondylolisthesis compared to routine steroid injection. Patients were randomly assigned to one of two groups: group one received pulsed RF, and group 2 received injection by steroids (triamcinolone) and bupivacaine. Multiple outcome measures were utilized which included the numeric rating scale (NRS), the Oswestry Disability Index (ODI), satisfaction status, and analgesic intake with assessment at 3, 6, and 12 months post-treatment. Significant pain relief was defined as 50% or more, whereas significant improvement in disability score was defined as reduction of 40% or more. Eighty patients were enrolled in the study and were divided into the two groups of study. PRF significantly reduced NRS at 6-month follow-up compared to steroid + bupivacaine. 75.6 ± 14.3% at pre-treatment and 19.3 ± 9.5% at 6 months (p = 0.001) in PRF group. The mean ODI is depicted in two groups of study (Fig. 1). Interestingly, ODI% was significantly lower in PRF group at 12 weeks and 6 months compare to steroid + bupivacaine group (p = 0.022 and 0.03, respectively), but it was not significantly different at 6 weeks (p = 0.31). Proportion of patients who did not require analgesics were significantly higher in PRF group compared to other group (p = 0.001) in Log-rank (Mantel-Cox) test. Our results demonstrated that the application of PRF might be more effective than steroid and bupivacaine injection in decreasing back pain due to degenerative facet pain and improvement in function of patients.

A new device used in the restoration of kinematics after total facet arthroplasty

Facet degeneration can lead to spinal stenosis and instability, and often requires stabilization. Interbody fusion is commonly performed, but it can lead to adjacent-segment disease. Dynamic posterior stabilization was performed using a total facet arthroplasty system. The total facet arthroplasty system was originally intended to restore the natural motion of the posterior stabilizers, but follow-up studies are lacking due to limited clinical use. We studied the first 14 cases (long-term follow-up) treated with this new device in our clinic. All patients were diagnosed with lumbar stenosis due to hypertrophy of the articular facets on one to three levels (maximum). Disk space was of normal height. The design of this implant allows its use only at levels L3–L4 and L4–L5. We implanted nine patients at the L4–L5 level and four patients at level L3–L4. Postoperative follow-up of the patients was obtained for an average of 3.7 years. All patients reported persistent improvement of symptoms, visual analog scale score, and Oswestry Disability Index score. Functional scores and dynamic radiographic imaging demonstrated the functional efficacy of this new implant, which represents an alternative technique and a new approach to dynamic stabilization of the vertebral column after interventions for spine decompression. The total facet arthroplasty system represents a viable option for dynamic posterior stabilization after spinal decompression. For the observed follow-up, it preserved motion without significant complications or apparent intradisk or adjacent-disk degeneration.

Clinical relevance of neuroforaminal patency after anterior cervical discectomy and fusion.

We sought to investigate the clinical relevance of neuroforaminal patency and facet degeneration one year after anterior cervical discectomy and fusion (ACDF). Previous studies were characterized by imprecise techniques and fragmentary measurements, and most lacked reliable clinical data and correlation analyses. Patients with cervical mono- or bi-level degenerative pathology were prospectively included. Neuroforaminal size and segmental height were determined quantitatively, and the degree of facet degeneration was assessed qualitatively before and one year after the operation, by computed tomography. Clinical data, such as the severity of neck and arm pain, were assessed on a visual analogue scale (VAS) from 0 to 10, and neck disability index (NDI) was recorded before and one year after the operation. Their correlation with radiological data was investigated. Seventy-nine patients aged 53.3 ± 11.3 years were included. One year after surgery, median VAS pain intensity was still significantly improved (neck, from 5 to 1; right arm, from 2 to 1; left arm, from 4 to 1) as was NDI (from 40 to 20). Neuroforaminal size showed a reduction on both sides (left, 0.0289 ± 0.09 cm(2); right, 0.0149 ± 0.08 cm(2)). One year after the operation, segmental height decreased and facet degeneration increased from measures taken before the operation. No correlations were found between neuroforaminal stenosis or the degree of facet degeneration and various clinical outcome parameters. The decrease in segmental height one year after ACDF leads in turn to secondary neuroforaminal stenosis and progressive facet degeneration. Of the various neuroforaminal variables used, none revealed a threshold value indicative of the presence or severity of radicular arm pain. This absence of correlation between imaging and clinical information is important and should be considered when allocating patients for surgical interventions.

Extraforaminal compression of the L-5 nerve root at the lumbosacral junction: clinical analysis, decompression technique, and outcome

Extraforaminal compression of the L-5 nerve encompasses multiple pathological entities and may result from disc herniations as well as bony (osteophytes or sacral ala) or ligamentous (sacroiliac ligament and lumbosacral band) compression. Several other factors, such as disc space collapse or coronal wedging, can also contribute to narrowing of the extraforaminal space. The extraforaminal space at L5-S1 has unique anatomical features compared with the upper lumbar levels, which makes surgical access to this region difficult. Minimally invasive techniques offer easier access to the region. The purpose of this study was to analyze the contributing factors for extraforaminal compression of the L-5 nerve and assess clinical outcome following surgical decompression. Fifty-two consecutive patients who underwent a minimally invasive far-lateral approach for extraforaminal compression of the L-5 nerve were retrospectively analyzed for clinical data, outcomes, and imaging features (type of disc prolapse, coronal wedging, degree of disc and facet degeneration, facet tropism, foraminal stenosis, osteophytes, and adjacent-level disease). The authors describe the surgical technique used in this study. The mean age of the patient sample was 57 years. Sixteen patients each had an extraforaminal ruptured disc or contained protrusion, and the remaining 20 patients had disc protrusions extending into the foraminal region or the lateral recess. Associated foraminal stenosis was found in 38.5%, and adjacent-level stenosis was noted in 22 cases (42.3%) and spondylolisthesis in 4 (7.7%). Osteophytes were noted in 18 cases. A coronal wedging angle ≥ 3° was found in 46.2%, and the laterality of wedging corresponded to the symptomatic side in 91% of cases. Fifteen patients (28.8%) complained of postoperative dysesthesias, which completely resolved in all cases within 6 months. The incidence of dysesthesias was more common in the ruptured disc group. There were no differences in clinical outcome among the different types of disc prolapses. The mean preoperative and postoperative visual analog scale scores were 7.6 and 3.6, respectively. The mean preoperative and postoperative Japanese Orthopaedic Association (JOA) scores were 6.4 and 13.8, respectively. The mean JOA recovery rate was 86.1%. According to the Macnab functional grading system, 96% of the patients had excellent or good grades at follow-up. A minimally invasive far-lateral approach to L5-S1 requires a good understanding of the regional anatomy and can provide good to excellent clinical results in properly selected cases. This approach is effective in decompressing the far-lateral and foraminal zones. Adequate preoperative diagnosis and tailoring the surgical procedure to address the relevant compressive element in each case is essential to achieving good clinical results.

Occult neural foraminal stenosis caused by association between disc degeneration and facet joint osteoarthritis: demonstration with dedicated upright MRI system

The aim of our study was to evaluate the presence of dynamic foraminal stenosis using a new low-field dedicated magnetic resonance (MR) unit with a balancing system that allows images to be acquired both in the recumbent and upright position. Imaging of lumbar spine with the patient in a supine, nonweight-bearing position is likely to misrepresent the degree and potential risk of spinal stenosis. In the period between September 2008 and May 2011, we selected 630 symptomatic patients aged 40-65years (mean age 56) who underwent conventional MR in clinostatic position. The study only included selected patients (total 160) who underwent clinostatic and orthostatic evaluation using a dedicated MR system (G-scan). The biomechanical parameters were also considered. Changes in the dimension of the neural foramina were compared using the presence of disc and facet degeneration by statistical analysis. Stenosis of the intervertebral foramen was never found in the presence of normal intervertebral discs either in the presence or in the absence of facet disease, in either clinostatic or orthostatic position. Sixty-one stenotic levels were detected which were visualised exclusively in scans obtained under weight-bearing conditions. We named this dynamic condition "occult stenosis". In all of these cases, disc disease was associated with facet pathology. Our data show that the association between disc pathology and facet osteoarthrosis can cause occult foraminal stenosis. Strategies to image the spine under physiological load conditions may improve the clinical diagnosis of radicular pain.

Lumbar L4-L5 ganglion cyst with hemicauda equina syndrome. Report of a case and review of the literature

Abstract Mostly associated with degenerative facet joints and spondylolisthesis, symptomatic lumbar juxta facet cysts - ganglion and synovial cysts are uncommon lesions of the spine. They can mimic herniated discs, causing low back pain, radiculopathy or even cauda equina syndrome; also some of them are associated with spinal instability. Referring to a case with hemicauda equina syndrome where microsurgical decompression was performed with very good result; alternative treatment solutions are discussed: conservative therapy for symptomatic lesions is often unsuccessful, spinal fusion should be made for those cases with spinal instability, although there are reports of spontaneous resolution of these cysts as well as the symptoms associated with them.

Correlation of Slipped Capital Femoral Epiphysis With Disk Degeneration

Spinal osteoarthritis is greater in patients with known hip pathology secondary to alterations in spinopelvic geometry. To our knowledge, no study has investigated the long-term impact of slipped capital femoral epiphysis (SCFE) on the spine. To evaluate the relationship between SCFE and the presence of degenerative disk disease and facet arthrosis. An anatomic study of disk degeneration in cadaveric lumbar spines with SCFE. An observational study was performed on 25 cadaveric specimens with SCFE and 647 controls that were identified out of 3100 total cadaveric specimens in an osteological collection. The specimens were evaluated for disk degeneration and facet arthrosis at L1/2 to L5/S1 using the classification of Eubanks and colleagues. Linear regression analyses were then used to determine the relationship between SCFE and lumbar disk and facet degeneration at each level, correcting for confounding factors such as age, sex, and race. Linear regression demonstrated a significant association (P<0.01) that was found between SCFE and degenerative disk disease at all levels from L1/2 to L5/S1. In addition, a significant association (P<0.01) was found between SCFE and facet arthrosis at all levels from L1/2 to L5/S1. The findings of this study show a relationship between SCFE and lumbar disk degeneration and facet arthrosis. This relationship may prove useful in predicting the course of spinal osteoarthritis in patients with SCFE.

Changes in the Adjacent Segment 10 Years After Anterior Lumbar Interbody Fusion for Low-Grade Isthmic Spondylolisthesis

Adjacent segment degeneration is a long-term complication of arthrodesis. However, the incidence of adjacent segment degeneration varies widely depending on the patient's age and underlying disease and the fusion techniques and diagnostic methods used. We determined (1) the frequency of adjacent segment degeneration and increased lordosis on imaging tests, (2) the frequency and severity of clinical sequelae of these findings, including revision surgery, and (3) the sequence of degeneration and risk factors for degeneration. Seventy-three patients underwent anterior lumbar interbody fusion for low-grade isthmic spondylolisthesis at one institution between October 2000 and February 2002. Forty-nine (67%) of the original patients had complete radiographic and clinical followup for 10 years. CT and MRI were performed at 5 years and 10 years in all cases. The disc height, sagittal profiles, and facet and disc degeneration at adjacent levels were examined to identify radiographic and clinical adjacent segment degeneration. Mean followup was 134.2 months (range, 120-148 months). Cranial segment lordosis increased (from 14.8° to 18.5°; p < 0.001), while caudal segment lordosis changed little (from 16.4° to 17.3°). Radiographic and clinical adjacent segment degeneration occurred in 19 (38.8%) and six (12.2%) patients, respectively, and two patients (4.1%) underwent revision surgery. Patients with adjacent segment degeneration had more advanced preexisting facet degeneration than patients without adjacent segment degeneration (odds ratio: 18.6; 95% CI, 1.97-175.54, p = 0.01). Acceleration of disc and facet degeneration occurred in 4.1% and 10.2%, respectively. Adjacent segment degeneration requiring surgery is rare, although radiographic adjacent segment degeneration is common after anterior lumbar interbody fusion for isthmic spondylolisthesis. The only risk factor we found was preexisting facet degeneration of the cranial segment. Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Surgical Management of Juxtafacet Cysts

Background Data: Synovial cysts occur most frequently in the lumbar spine (88-99%). They are viewed as regenerative changes that are associated with hypermobility and instability of a motion segment as seen with spondylolisthesis and facet joint instability and facet degeneration. There is extensive controversy regarding the definition, prevalence, pathogenesis, risk factors, and most importantly, treatment options for synovial cysts management. Purpose: To assess the outcome of various surgical procedures done for the treatment of lumbar juxtafacet cysts.Study Design: Retrospective clinical case study. Patients and Methods: The data of 26 patients (17 males and 9 females) who underwent surgery for lumbar juxtafacet cysts, during the years 2005 to 2010 was reviewed. The patients age ranged from 42 to 68 years (mean 55.9 years ± 6). The most affected level was L4–L5 (21 patients), followed by L3–L4 (3 patients), while the least affected level proved to be L5-S1 (2 patients). Five patients had in addition,spondylolisthesis of the involved segment and four patients had hypermobile segments. All patients had signs of nerve root compression that failed to respond to conservative treatment preoperatively. Various patients groups were subject of alternative surgical modalities; as Microscopic laminotomies and medial facetectomies were performed in 5 patients (laminotomy group), formal Laminectomies and medial facetectomy in 12 patients (laminectomy group), while complete facetectomy with additional fusion for spondylolisthesis and hypermobility were performed with 9 patients (fusion group).Results: Conservative treatment proved to be ineffective in all cases. The mean follow up duration was for 28 months (± 7.5) ranging from 18 to 46 months. Excellent to good outcome was achieved in 17 of 26 patients (65.4%), while 6 patients (23.1%) showed fair results and 3 (11.5%) showed poor results. Persistent low back pain was not observedat all among patients of the fusion group (0 out of 9 patients); while being more common in patients operated without fusion (laminotomy and laminectomy groups) (7 out of 17 patients). Moreover, three patients of the latter group have developed grade 1 olisthy during the follow-up duration, and hence requiring additional fusion.Conclusion: Juxtafacet cysts can be treated effectively through different surgical modalities, which should be tailored according to the anatomical and dynamic properties of the patients’ spines, as well as their presenting complaints. The presence of radiological instability even in the absence of overt slippage may necessitate the need for fusion. (2013ESJ050)

Treatment of facet cysts associated with neurogenic intermittent claudication with x-stop.

Facet degeneration often leads to the formation of synovial facet cysts. As facet cysts invade the spinal canal, they become a contributing factor to spinal stenosis. Previous studies have demonstrated successful treatment of neurogenic intermittent claudication (NIC), a major symptom of spinal stenosis, with an interspinous process device. To compare clinical outcomes of patients with and without synovial facet cysts treated with an interspinous process device. Retrospective review of prospective data of consecutive patients undergoing the X-Stop procedure at an institution. Visual Analog Scale; Oswestry Disability Index; sitting, standing, and walking tolerances; and satisfaction survey. Review of all patients from 2006 to 2010 undergoing X-Stop procedure at an institution. Imaging studies were used to identify the presence and measure the size of the facet cysts in 285 patients with a minimum of 6-month follow-up. Comparative clinical outcomes determined if X-Stop is a successful treatment option for patients with NIC in conjunction with synovial facet cysts (<3 mm, ≥3 mm). Fifty-eight of 285 patients (20.4%) were determined to have a synovial cyst as a contributing component of spinal stenosis. Twelve of 58 patients were noted to have a cyst ≥3 mm. The mean follow-up time for patients with and without a facet cyst was 21 months (6-55±12 mo) and 22 months (6-61±12 mo), respectively. The age of the patient at the time of the operation with and without facet cysts was 73 (±10 y). Patients without synovial cysts, with synovial cysts, and cysts ≥3 mm had an average change in Oswestry Disability Index of 15.6, 15.8, and 16.2, respectively. Visual Analog Scale scores were 2.3, 1.8, and 2.3, respectively. In addition, on satisfaction surveys 72.4%, 82.0%, and 77.8% were either very or somewhat satisfied, respectively. Overall complications included 4 spinous process fracture, 4 hematomas, 1 wound infection, and 1 implant migration. No statistical difference was noted in any of the outcome measures among patients with small facet cysts, large facet cysts, or without facet cysts when treated with an interspinous process device. We can thus conclude that X-Stop is an appropriate treatment consideration for NIC with or without the presence of synovial facet cysts.

Biomechanical behavior of two different cervical total disc replacement designs in relation of concavity of articular surfaces: ProDisc-C® vs. Prestige-LP®

Recently, many cervical total disc replacement (TDR) devices have been introduced in a variety of designs in an attempt to recreate motion behavior of the normal cervical spine thereby to limit the progression of adjacent degeneration. The purposes of this study were to evaluate and compare the range of motion (ROM) and location of instant center of rotation (COR), and load sharing characteristics of two major products with different design concepts in cervical TAR-Prodisc-C® and Prestige-LP®. A 3-D finite element (FE) model of intact cervical spine (C3-6) was made from CT scans of a normal person and validated. Based on this model, postoperative FE models simulating TDR implantation at the C4-5 disc space were made for Prodisc-C® (Synthes Spine, Paoli, PA) and Prestige-LP® (Medtronic Sofamor Danek, Memphis, TN), respectively. These two TDR devices feature different design concepts that affect kinematics: Rotations and some translations were allowed at the articulating surface of Prestige LP® as the ‘concave down’ articulating surface is less constrained whereas only rotations were allowed with Prodisc-C® that features ball & socket articulating surface in ‘concave up’ orientation. Hybrid protocol (intact: 1Nm) with a compressive follower load of 73.6N were applied at the superior endplate of the C3 vertebral body. The inferior endplate of C6 vertebral body was constrained in all directions. At the index level, Prestige-LP® showed 15% less motion than Prodisc-C® in extension and about the same in flexion. Differences in ROM were negligible at the adjacent level. Here, the COR of Prestige-LP® was located more postero-inferiorly than that of Prodisc-C® by about 1-mm during extension at the index level. Facet load was less with Prestige-LP® by about 10% at the index level but 14% more at the adjacent level. The results of this study indicated that the biomechanical behavior of the postoperative cervical spine can be indeed influenced by the design features such as concavity orientation and extent of constraint of the articulating surfaces. Particularly, ROM and COR location as well as the facet loads at the index level and adjacent levels were more sensitive during extension. It would be interesting to note that resulting differences in facet load at the index and adjacent levels between the two designs will manifest to different clinical results in terms of postoperative facet degeneration.

Biomechanics of adjacent segments after a multilevel cervical corpectomy using anterior, posterior, and combined anterior-posterior instrumentation techniques: a finite element model study

Background contextAdjacent segment degeneration (ASD) after cervical fusion is a clinical concern. Despite previous studies documenting the biomechanical effects of multilevel cervical fusion on segments immediately superior and inferior to the operative segments, the pathogenesis of the initiation of degeneration progression in neighboring segments is still poorly understood. PurposeTo test the hypothesis that changes in range of motion, disc stresses, and facet loads would be highest at the superior adjacent segment (C3–C4) after anterior C4–C7 corpectomy and fusion and that these changes would be the least in anterior fixation and the greatest in posterior or combined anterior-posterior instrumentation techniques. Study designA finite element (FE) analysis of adjacent vertebral segment biomechanics after a two-level corpectomy fusion with three different fixation techniques (anterior, posterior, and combined anterior-posterior). MethodsA previously validated three-dimensional FE model of an intact C3–T1 segment was used. From this intact model, three additional instrumentation models were constructed using anterior (rigid screw-plate), posterior (rigid screw-rod), and combined anterior-posterior fixation techniques after a C4–C7 corpectomy and fusion. Motion patterns, disc stresses, and posterior facet loads at the levels cephalad and caudal to the fusion were assessed. ResultsRange of motion, disc stresses, and posterior facet loads increased at the adjacent segments. Use of posterior fixation, whether alone or in combination with anterior fixation, infers higher changes in segmental motion, disc stresses, and posterior facet loads at adjacent segments compared with the use of anterior fixation alone. The superior C3–C4 motion was most affected during lateral bending and the inferior C7–T1 motion was most affected during flexion, whereas both superior C3–C4 and inferior C7–T1 motions were least affected during extension. However, disc stresses and facet loads were most affected during extension. Hence, it is speculated that the most remodeling changes in discs and facets might be related to the least changes in extension motion. ConclusionsBiomechanical factors such as increased mechanical demand and motion that have been associated with the development of ASD progression are highest in the segment immediately superior to the fusion. These changes are even more pronounced when the fixation technique involves the addition of posterior instrumentation, thereby supporting the hypothesis of the present study. Increased degrees of stiffening of the fused segments not only may lead to degenerative changes in the disc but may also predispose the segments to premature facet degeneration. Over subsequent time period, any remaining construct micro-motion is further eliminated with fusion of the posterior facet joints and the remaining regions in the disc space also filled in with bone, which eventually results in a circumferential type of fusion. After a circumferential fusion, authors, however, speculate that the role of instrumentation in ASD progression might not be significant. In fact, sufficient evidence to support this speculation is still lacking in the literature.

Long‐term Follow‐up of Cervical Facet Medial Branch Radiofrequency Treatment With the Single Posterior‐lateral Approach: An Exploratory Study

Over 50% of patients presenting to pain clinic with neck pain have the cervical facet joints as the source of pain. Radiofrequency (RF) treatment of the medial branch, innervating the facet joint, is a therapeutic option. The objectives of this study were to evaluate the therapeutic effect and its duration of RF treatment, using the single posterior-lateral approach in patients suffering from facet joint degeneration and to identify predictors for a long-term effect. Of the 130 consecutive patients with axial neck pain referred to the University Pain Center Maastricht, 67 fulfilled the inclusion criteria. The therapeutic effect was measured using the Patients' Global Impression of Change (PGIC) scale. Retrospective data were made complete using newly collected PGIC follow-up data. A Kaplan-Meier curve evaluated the long-term therapeutic effect. Possible predictors of outcome were evaluated. Two patients refused to participate and in the remaining 65 patients, overall pain relief was reported in 55.4% at 2-month follow-up. Moderately, important change of improvement and substantial change of improvement were seen in 50.8% of patients. At 3-year follow-up, 30% still reported pain reduction. Spinal treatment level was the only predictor found. Radiofrequency treatment of the cervical facet joints using a single posterior-lateral approach is a promising technique in patients with chronic neck pain due to facet degeneration. The short-term and long-term therapeutic effects of this intervention justify a randomized controlled trial to estimate the efficacy of cervical facet joint RF treatment in a chronic neck pain population.

Protecting facet joints post-lumbar discectomy: Barricaid annular closure device reduces risk of facet degeneration

Lumbar discectomy is an effective treatment for lumbar disc herniation (LDH). Although the majority of patients experience successful outcomes, a significant fraction will experience a recurrence of their back pain due to facet joint degeneration. Facet joint degeneration after discectomy may be the result of excessive nuclear removal, disc space narrowing, and annular injury. This study investigated whether implantation with the Barricaid annular closure device (ACD) during discectomy reduced the rate of facet degeneration. Inclusion criteria were primary lumbar disc herniation failing conservative treatment, Visual Analog Scale (VAS) Leg≥40/100, Oswestry Disability Index (ODI)≥40/100 and defects that were ≤60 mm2 (Barricaid arm only), and patient age 18-75. CT interpretations were collected preoperatively and 12 months post-discectomy. Patients implanted with Barricaid had significantly reduced rates and grades of facet degeneration than patients without Barricaid. Reinforcing the annulus fibrosus with Barricaid during lumbar discectomy may slow the progression of facet joint degeneration.