Symptomatic Degenerative Disc Research Articles

Regenerative therapies for lumbar degenerative disc diseases: a literature review.

This review aimed to summarize the recent advances and challenges in the field of regenerative therapies for lumbar disc degeneration. The current first-line treatment options for symptomatic lumbar disc degeneration cannot modify the disease process or restore the normal structure, composition, and biomechanical function of the degenerated discs. Cell-based therapies tailored to facilitate intervertebral disc (IVD) regeneration have been developed to restore the IVD extracellular matrix or mitigate inflammatory conditions. Human clinical trials on Mesenchymal Stem Cells (MSCs) have reported promising outcomes exhibited by MSCs in reducing pain and improving function. Nucleus pulposus (NP) cells possess unique regenerative capacities. Biomaterials aimed at NP replacement in IVD regeneration, comprising synthetic and biological materials, aim to restore disc height and segmental stability without compromising the annulus fibrosus. Similarly, composite IVD replacements that combine various biomaterial strategies to mimic the native disc structure, including organized annulus fibrosus and NP components, have shown promise. Furthermore, preclinical studies on regenerative medicine therapies that utilize cells, biomaterials, growth factors, platelet-rich plasma (PRP), and biological agents have demonstrated their promise in repairing degenerated lumbar discs. However, these therapies are associated with significant limitations and challenges that hinder their clinical translation. Thus, further studies must be conducted to address these challenges.

Five-year Follow-up of a Prospective Food and Drug Administration Investigational Device Exemption Trial Evaluating a PEEK-on-Ceramic Cervical Disc Replacement.

Prospective trial comparing the investigation group to propensity matched historic control group. To evaluate 5-year results of single-level PEEK-on-ceramic cervical total disc replacement (TDR) compared to a propensity matched anterior cervical discectomy and fusion (ACDF) control group. Cervical TDR has gained acceptance as treatment for symptomatic disc degeneration. The design and materials used in these devices continue to evolve. Data were collected in the Food and Drug Administration Investigational Device Exemption trial for the PEEK-on-ceramic Simplify(®) Cervical Artificial Disc (n=150) with comparison to a propensity matched ACDF control group (n=117). All patients were treated for single-level cervical disc degeneration with radiculopathy and/or myelopathy. Clinical outcome was based on composite clinical success (CCS), Neck Disability Index (NDI), visual analog scales (VAS) assessing pain, re-operations, and satisfaction. Radiographic measures included segmental range of motion (ROM), disc space height, and heterotopic ossification (HO). Evaluations were performed pre-operatively and post-operatively within 2 and 6 weeks, and 3, 6, 12 months, and annually thereafter. At 5-year follow-up, CCS was significantly greater with TDR than ACDF (91.1% vs. 74.6%; P<0.01). In the TDR group, the mean NDI score was 63.3 pre-operatively, reduced significantly to 23.1 at 6 weeks and remained below 20 throughout 5-year follow-up. In the ACDF group, the mean pre-operative NDI score was 62.4, decreasing to 33.7 at 6 weeks, and ranged from 25.9 to 21.5 throughout follow-up. Mean NDI scores were significantly lower in TDR group at all post-operative points (P<0.05). Mean TDR ROM was 7.3o pre-operatively and 10.1o at 5 years. Bridging HO occurred in 9%. With TDR, there were 6 re-operations (4.0%) vs. 11 (9.4%) with ACDF (P>0.40). PEEK-on-ceramic TDR produced significantly improved outcomes maintained throughout 5-year follow-up, were similar or superior to ACDF, supporting TDR in appropriately selected patients.

The Efficacy of Second-Generation Cervical Spine Arthroplasty: A 5-Year Perspective

Objective: The aim of this study was to determine the surgical outcomes of second-generation cervical arthroplasty in patients with symptomatic cervical disc degeneration at approximately 5 years of follow-up.Methods: A retrospective study was conducted of consecutive patients who underwent elective cervical spine arthroplasty at our institution with the use of a second-generation cervical prosthesis. The inclusion criteria were: (1) patients aged 25 to 50 years, (2) patients undergoing primary cervical surgery, (3) a minimum follow-up of 5 years. Demographic, clinical, surgical, and radiological data were collected and analyzed for patients who met the inclusion and exclusion criteria.Results: Thirty-seven patients were identified. The mean final follow-up was 75.1 months (range, 62.5–92.2 months). Statistically significant improvement was observed at the end of follow-up in the cervical disability index, neck pain, and radicular pain (p&lt;0.001). In total, 89.1% of patients reported being satisfied or very satisfied. During follow-up, 4 patients required reintervention, including 2 for adjacent segment syndrome, 1 for possible implant failure, and 1 for a prevertebral collection. The mean mobility of the operated segment at 5 years was 8.1 (standard deviation, 5.91). Additionally, radiologically, 1 patient exhibited heterotopic ossification, and 5 patients had asymptomatic adjacent segment syndrome.Conclusion: Promising outcomes are associated with second-generation cervical arthroplasty in the management of symptomatic cervical disc degeneration. The improvement in clinical scores, preservation of segmental mobility, and low incidence of complications such as heterotopic ossification and reintervention underscore the potential benefits of second-generation cervical arthroplasty.

Allogeneic Disc Progenitor Cells Safely Increase Disc Volume and Improve Pain, Disability, and Quality of Life in Patients With Lumbar Disc Degeneration-Results of an FDA-Approved Biologic Therapy Randomized Clinical Trial.

Progenitor cells derived from intervertebral disc tissue demonstrated immunomodulatory and regenerative properties in preclinical studies. We report the safety and efficacy results of a US Food and Drug Administration-approved clinical trial of these cells for the treatment of symptomatic degenerative disc disease. Sixty patients with symptomatic single-level lumbar degenerative disc disease (mean age 37.9 years, 60% men) were enrolled in a randomized, double-blinded, placebo-controlled Phase I/Phase II study at 13 clinical sites. They were randomized to receive single intradiscal injections of either low-dose cells (N = 20), high-dose cells (N = 20), vehicle alone (N = 10), or placebo (N = 10). The primary endpoint was mean visual analog scale (VAS) pain improvement >30% at 52 weeks. Disc volume was radiologically assessed. Adverse events (AEs), regardless of whether they were related to treatment, were reported. Patients were assessed at baseline and at 4, 12, 26, 52, 78, and 104 weeks posttreatment. At week 52, the high-dose group had a mean VAS percentage decrease from baseline (-62.8%, P = 0.0005), achieving the endpoint of back pain improvement >30%; the mean change was also significantly greater than the minimal clinically important difference of a 20-point decrease (-42.8, P = 0.001). This clinical improvement was maintained at week 104. The vehicle group had a smaller significant decrease in VAS (-52.8%, P = 0.044), while the low-dose and placebo groups showed nonsignificant improvements. Only the high-dose group had a significant change in disc volume, with mean increases of 249.0 mm3 (P = 0.028) at 52 weeks and 402.1 mm3 (P = 0.028) at 104 weeks. A minority of patients (18.3%) reported AEs that were severe. Overall, 6.7% of patients experienced serious AEs, all in the vehicle (n = 1) or placebo (n = 3) groups, none treatment related. High-dose allogeneic disc progenitor cells produced statistically significant, clinically meaningful improvements in back pain and disc volume at 1 year following a single intradiscal injection and were safe and well tolerated. These improvements were maintained at 2 years post-injection. NCT03347708-Study to Evaluate the Safety and Preliminary Efficacy of Injectable Disc Cell Therapy, a Treatment for Symptomatic Lumbar Intervertebral Disc Degeneration.

Clinical Outcome of Lumbar Hybrid Surgery in a Consecutive Series of Patients with Long-term Follow-up.

This was a retrospective study combined with attempted prospective patient contact to collect current data. The purpose of this study was to investigate long-term clinical outcome of patients undergoing lumbar hybrid surgery (total disc replacement (TDR) at one level and fusion at an adjacent level. Many patients with symptomatic lumbar disc degeneration are affected at more than one level. Lumbar TDR was introduced as a fusion alternative; however, some disc levels are not amenable to TDR and fusion is preferable at such levels. Hybrid surgery was introduced as an option to fusing multiple levels. A consecutive series of 305 patients undergoing lumbar hybrid surgery was identified beginning with the first case experience in 2005. Operative and clinical outcome data including visual analog scales (VAS) assessing back and leg pain, Oswestry Disability Index (ODI), and re-operations were collected. The mean follow-up duration was 67.1 months. There were statistically significant improvements (P<0.01) in the mean values of all three clinical outcome measures: VAS back pain scores improved from 6.7 to 3.3; leg pain improved from 4.3 to 2.0; and ODI scores improved from 45.5 to 24.6. There were no significant differences in pain and function scores for patients with minimum 10-year follow-up vs. those with shorter follow-up duration. Re-operation occurred in 16.1% of patients, many of which involved removal of posterior instrumentation at the fusion level (6.2% of study group, 38.8% of re-operations). Re-operation involving the TDR level occurred in 9 patients (2.9%), only 3 of which (1.0%) involved TDR removal/revision. This study supports that for many patients with multilevel symptomatic disc degeneration, hybrid surgery is a viable surgical option. Significant improvements were demonstrated in pain and function scores with no diminished improvement in scores among patients with more than 10-year follow-up.

Is the Use of Intraoperative Neuromonitoring Justified During Lumbar Anterior Approach Surgery?

Intraoperative neuromonitoring (IONM) became widely used in spine surgery to reduce the risk of iatrogenic nerve injury. However, the proliferation of IONM has fallen into question based on effectiveness and costs, with a lack of evidence supporting its benefit for specific spine surgery procedures. The purpose of this study was to evaluate the use of IONM and the rate of neurological injury associated with anterior lumbar spinal surgery. This was a retrospective study on a consecutive series of 359 patients undergoing lumbar anterior approach surgery for anterior lumbar interbody fusion (ALIF), total disc replacement (TDR), or hybrid (ALIF with TDR) for the treatment of symptomatic disc degeneration. Patients undergoing any posterior spine surgery were excluded. Operative notes were reviewed to identify any changes in IONM and the surgeon's response. Clinic notes were reviewed up to 3 months postoperatively for indications of iatrogenic nerve injury. There were 3 aberrant results with respect to IONM. Changes in IONM of a lower extremity occurred for 1 patient (0.3%). The surgeon evaluated the situation and there was no observable reason for the IONM change. Upon waking, the patient was found to have no neurological deficit. There were 2 cases of neurologic deficits in this population, which were classified as false-negatives of IONM (0.56%, 95% CI: 0.1% to 1.8%). In both cases, the patients were found to have a foot drop after the anterior approach surgery. In this study, there was 1 false-positive and 2 false-negative results of IONM. These data suggest that IONM is not beneficial in this population. However, many surgeons may feel obligated to use IONM for medicolegal reasons. There is a need for future studies to delineate cases in which IONM is beneficial and the type of monitoring to use, if any, for specific spine surgery types. This study questions the routine use of IONM in anterior lumbar approach surgery for the treatment of symptomatic disc degeneration. This has significant implications related to the cost of this practice.

Evaluating alternatives to dual-energy x-ray absorptiometry for assessing bone quality in patients undergoing spine surgery.

The purpose of this study was to compare and contrast lumbar bone quality and osteoporosis/osteopenia screening results via dual-energy x-ray absorptiometry (DEXA), CT, and MRI. A consecutive series of 426 candidates screened for lumbar disc replacement over a 5-year period beginning in 2018 was reviewed. Patients with a preoperative lumbar spine DEXA scan and a CT and/or MRI scan were included. The primary outcome measures included the bone mineral density (BMD) and osteoporosis or osteopenia classification from DEXA scans, Hounsfield units (HUs) for CT, and vertebral bone quality (VBQ) assessment for MRI. Patients were included if they had a DEXA scan within 1 year of an MRI or CT scan. DEXA BMD scores from composite or level-by-level reports were recorded. Asynchronous MRI and CT measurements were conducted using PACS. Interrater and intrarater reliability scores were generated for both CT and MRI measurements and ranged from 1.000 for MRI L1-4 scans to 0.683 for MRI VBQ. All 3 types of scans were statistically significantly correlated with one another; however, CT was more strongly correlated with the lumbar DEXA value (r = 0.439, p < 0.001). The correlation between MRI VBQ and DEXA was -0.103, (p < 0.045). The CT level-by-level measurements correlate with the corresponding level-by-level DEXA BMD values (correlation ranging from 0.531 to 0.289, p < 0.001 to p = 0.007). CT HU values were more strongly related to osteoporosis/osteopenia classification based on DEXA T-scores than were MRI VBQ values. Receiver operating characteristic analyses found that the area under the curve was 0.817 for CT and 0.539 for MRI. These results demonstrate that CT HUs more closely correlate to DEXA scores than MRI VBQ in this population of patients undergoing surgery for symptomatic disc degeneration. Thus, CT may be an alternative to DEXA for assessing VBQ in this population.

Lumbar paraspinal muscle morphology is associated with spinal degeneration in patients with lumbar spinal stenosis

BACKGROUND CONTEXTLumbar spinal stenosis (LSS) has been reported to induce changes in paraspinal muscle morphology, but objective physical function and degenerative spine conditions are rarely assessed. PURPOSETo identify factors associated with paraspinal muscle morphology using objective physical and degenerative spine assessments in patients with LSS. STUDY DESIGN/SETTINGCross-sectional design. PATIENT SAMPLESeventy patients with neurogenic claudication caused by LSS, receiving outpatient physical therapy. OUTCOME MEASURESCross-sectional area (CSA) and functional CSA (FCSA) of the multifidus, erector spinae, and psoas muscles, the severity of stenosis, disc degeneration, and endplate abnormalities were evaluated by magnetic resonance imaging, as well as sagittal spinopelvic alignment by X-ray. Objective physical assessments included pedometry and claudication distance. Patient-reported outcomes included the numerical rating scale of low back pain, leg pain, and leg numbness, and the Zurich Claudication Questionnaire. METHODSTo assess the impact of LSS on paraspinal muscles, FCSA and FCSA/CSA were compared between the dominant and nondominant sides based on the patients’ neurogenic symptoms, and multivariable regression analyses adjusted for age, sex, height, and weight were performed; p<.05 was considered significant. RESULTSSeventy patients were analyzed. At one level below the maximum stenotic level, erector spinae FCSA on the dominant side was significantly lower than that on the nondominant side. In the multivariable regression analyses, at one level below the symptomatic level, disc degeneration, endplate abnormalities, and lumbar spinopelvic alignment, such as decreased lumbar lordosis and increased pelvic tilt, were negatively associated with multifidus FCSA and FCSA/CSA ratio. A significant association was observed between dural sac CSA and erector spinae FCSA. Throughout L1/2 to L5/S, disc degeneration, endplate abnormalities, and lumbar spinopelvic alignment were negatively associated with multifidus and erector spinae FCSA or FCSA/CSA. CONCLUSIONSLumbar paraspinal muscle asymmetry caused by LSS was observed only in erector spinae. Disc degeneration, endplate abnormalities, and lumbar spinopelvic alignment, rather than spinal stenosis and LSS symptoms, were more associated with paraspinal muscle atrophy or fat infiltration.

Impact of previous lumbar spine surgery on the outcome of lumbar total disc replacement: analysis of prospective 5-year follow-up study data.

It is sometimes anticipated that patients with prior spine surgery will have a compromised outcome from future procedures. The purpose of this study was to compare TDR outcomes in patients with prior lumbar spine surgery to those with no previous surgery. Post hoc analysis was performed on 5-year follow-up data collected prospectively in the multi-centre FDA-regulated trial for the activL® Artificial Disc which involved 376 patients treated for single-level symptomatic disc degeneration. Clinical outcome measures included the Oswestry Disability Index (ODI), visual analog scales (VAS) assessing back and leg pain, SF-36, adverse events, and re-operations. Radiographic outcomes included flexion/extension range of motion (ROM) and translation of the operated segment. Patients were divided into two groups: Prior Lumbar Surgery (PLS, n = 92) and No Prior Lumbar Surgery (NPLS, n = 284). Baseline demographics were similar in the two groups. ODI, VAS, and SF-36 Physical Component Scale scores improved significantly (p < 0.05) from baseline in both groups with improvements maintained through 5-year post-TDR with no significant differences between groups. There were no statistically significant differences in rates of serious device-related events, procedure-related events, or re-operations. While ROM was significantly less prior to TDR surgery in the PLS group, there was no significant difference in ROM at post-operative points. Prior lumbar spine surgery was not associated with compromised outcomes following TDR. These results are in line with reports from earlier studies with shorter follow-up, finding that non-destabilizing prior surgery is not a contra-indication for TDR provided that selection criteria are met. Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

172. Seven-year progression and 10-year prediction of adjacent level degeneration and disease after lumbar total disc replacement: A post hoc analysis of a prospective clinical trial with 7-year follow-up

<h3>PURPOSE</h3> To understand the progression of radiographic adjacent-level degeneration (ALDeg) seven years after lumbar total disc replacement (TDR) and the relationship of these changes with range of motion (ROM) and symptomatic adjacent-level disease (ALDis) using the seven-year follow-up data from a prospective, multicenter activL Food and Drugs Administration (FDA) Investigational Device Exemption (IDE) randomized controlled trial. <h3>METHODS</h3> Patients with single-level, symptomatic lumbar disc degeneration who were unresponsive to 6 months of nonoperative care, received activL or ProDisc-L, and had radiographs available were analyzed for the incidence for ALDeg and progression of ALDeg (ΔALDeg). ALDeg presence was determined using a modified, four-point, Kellgren-Lawrence scale. Incidence of ALDis was identified in patients who received activL or ProDisc-L with or without available radiographs. ALDis was defined as the need for reoperation at the segment adjacent to the index segment. The possible relationship between ROM and ΔALDeg was also investigated. Logistic regression modeling was used to predict ALDeg and ALDis outcomes to 10 years. <h3>RESULTS</h3> At baseline, 25% of patients had ALDeg. By seven-year follow-up, 33% of patients had ALDeg and 80% of these patients showed no ΔALDeg. Only a small percentage (3.4%) of patients had severe ΔALDeg by seven-year follow-up; the majority of patients had mild (75.9%) or moderate (20.7%) ΔALDeg by seven years. Incidence of ALDis was identified in 4 patients through seven-year follow-up (2.4%). Three patients received fusion at an adjacent level and one patient underwent fusion at the index and adjacent levels to treat stenosis at both levels along with symptomatic disc degeneration at the adjacent level. Improvement in ROM from baseline ranged from 0°to 16.4° at seven-year follow-up. For each degree in ROM gained at the TDR level, there was a consistent decrease in the percent of patients with ΔALDeg. Of patients having any improvement in ROM from baseline at the TDR level, only 16.9% had ΔALDeg; of patients having a 10°improvement in ROM, 0% of patients had ΔALDeg. The predicted probability of ALDeg after lumbar TDR was 53.9% by 10 years. In contrast, the predicted probability of clinical ALDis was only 2.8% by 10 years. <h3>CONCLUSIONS</h3> Post hoc analysis of seven-year data from a prospective trial confirm relatively low rates of ALDeg, ALDeg progression, and clinical ALDis after TDR over the long-term, with predicted rates being low through to 10 years. Improvement in ROM may be associated with reduced ΔALDeg. <h3>FDA DEVICE/DRUG STATUS</h3> activL total disc replacement (Approved for this indication), prodisc-L total disc replacement (Approved for this indication).

29. Imaging outcome at 24-month follow-up in a prospective, multicenter study of two-level cervical arthroplasty with a PEEK on ceramic artificial disc

<h3>BACKGROUND CONTEXT</h3> The use of cervical total disc replacement (cTDR) continues to increase. The implants continually evolve with respect to design and materials. Imaging studies of these devices provides insight to their ability to provide and maintain range of motion (ROM), disc height, and depending on the implant materials, facet joint assessment. <h3>PURPOSE</h3> The purpose of this study was to evaluate the imaging outcome of a PEEK-on-ceramic artificial disc for the treatment of two-level cervical disc disease. <h3>STUDY DESIGN/SETTING</h3> Data for this study came from a prospective, multicenter, non-randomized, historically controlled FDA Investigational Device Exemption (IDE) trial evaluating the Simplify®Cervical Artificial Disc for use at two levels. <h3>PATIENT SAMPLE</h3> Two-level cTDR was performed in 182 patients treated for symptomatic cervical disc degeneration with radiculopathy/myelopathy. <h3>OUTCOME MEASURES</h3> The primary outcome measures were ROM, disc height, and heterotopic ossification (HO) of the treated levels. MRI was used to assess the facet joints. <h3>METHODS</h3> The cTDR is composed of PEEK endplates with a mobile ceramic core. Radiographic evaluations were performed preoperatively, at hospital discharge, and 6 weeks, and 3, 6, 12, and 24 months postoperatively. MRI was performed pre- and 24 months postoperatively. All images were evaluated by an independent core lab. HO was evaluated based on a 0 (normal) to 4 (bridging bone) scale. Facets joints were scored on a 4-point scale ranging from 0 (normal) to 3 (severe degeneration) based on the MRI performed pre- and 24 months postoperatively. <h3>RESULTS</h3> At the superior cTDR level, the mean ROM improved from 8.0° prior to surgery to 9.5° at 24-month follow-up. At the inferior level, the values were 6.6° and 8.9°, respectively. At both operated levels, mean disc height increased postoperatively and the increase was maintained through 24-month follow-up. At the superior index level, the preoperative mean height was 3.1 mm and at 24 months it was 4.3 mm. At the inferior index level, the preoperative height was 3.1 mm and was 4.0 at 24 months. HO rates at 24-month follow-up were, the superior index level, severe HO (Grade 3) occurred in 8 patients (5%). Bridging HO (Grade 4) was also seen in 8 patients (5%). At the inferior index level, severe and bridging HO was seen in 17 (10%) and 5 (3%) patients, respectively. There was a lack of facet degeneration progression assessed on MRI between pre- and 24-month follow-up. No patient had severe facet degeneration at either operated level at either time point. The percentage of patients with a grade of moderate facet degeneration did not change at either level 8% at the superior index level and 5% at the inferior index level. At both levels, there appeared to be patients changing from the "none" category to the "mild" category. At the superior level prior to surgery, the figures for "none" and "mild" were 62% and 30% respectively. At 24-month follow-up, the figures were 52% and 39%, respectively. A similar pattern was seen at the inferior index level. <h3>CONCLUSIONS</h3> This study adds to the expanding evidence that two-level cTDR increases and maintains ROM and disc height and through 24-month follow-up. The majority of cTDR patients did not experience bridging HO. This PEEK-on-ceramic cTDR produces minimal artifact, allowing for reliable MRI visualization. This was used to evaluate the facet joints and a lack of facet degeneration progression was found. <h3>FDA DEVICE/DRUG STATUS</h3> Simplify Cervical Artificial Disc 2-level (Approved for this indication).

101. Lumbar total disc replacement: occurrence of device removal or revision surgery during a 20-year experience with 1,775 patients

<h3>BACKGROUND CONTEXT</h3> A concern expressed about lumbar total disc replacement (TDR) has been safety. One measure of safety is the need for subsequent surgery for implant removal or revision. This may be of particular importance considering TDR removal/revision generally requires re-operation through the anterior approach with the corresponding increased risk of vascular injury. <h3>PURPOSE</h3> The purpose of this study was to analyze the incidence of, and reasons for, lumbar TDR removal or revision. <h3>STUDY DESIGN/SETTING</h3> The study was based on retrospective record review followed by a mailing and/or telephone call to collect current information from patients who had not been seen recently in the clinic. <h3>PATIENT SAMPLE</h3> A consecutive series of 1,775 lumbar TDR patients, beginning with the first case experience in 2000, was reviewed to identify those undergoing re-operation for TDR removal or revision. Only patients who were at least 2 years postoperative were included. All patients were treated for symptomatic disc degeneration unresponsive to nonoperative care. <h3>OUTCOME MEASURES</h3> The primary outcome measure was the occurrence of TDR removal or revision. <h3>METHODS</h3> The mean follow-up was 89.0 months with a median of 76 months and maximum of 251 months. For each case of device removal/revision, the reason, duration from index surgery and procedure performed were recorded. <h3>RESULTS</h3> In the series of 1,775 patients, 26 (1.46%) underwent TDR removal or revision. Removal was performed in 23 patients (1.29%) and 3 patients underwent TDR revision (0.17%). Based on the total number of 2,082 TDRs implanted in the 1.775 patients, the rates of removals and revisions were 1.15% and 0.14%, respectively. Removals included: 10 for migration and/or loosening, 3 developed problems after a trauma, 3 had ongoing pain, 2 developed lymphocytic reaction to device materials, and one each of: TDR was too large and replaced with a smaller device, vertebral body fractures (osteoporosis), developed a lytic lesion, device subsidence and facet arthrosis, and infection seeded from a chest infection at 146-month post-TDR. The 3 revisions were: repositioning the core (technique error), repositioning device after displacement, and core replacement due to wear/failure. With respect to timing, 34.6% of removals/revisions occurred within one month after the index implantation. Of note, 42.3% of revisions/removals occurred in the first 25 TDR cases performed by individual surgeons. Vascular complication during TDR removal occurred in one patient with an iliac vein tear whose TDR was removed due to trauma including spinal fracture. The series included 264 patients with verified minimum 15-year follow-up. In this subset, only one patient underwent removal/revision surgery 15 or more years after TDR. This was the patient who underwent TDR removal due to trauma-related spinal fracture. <h3>CONCLUSIONS</h3> In this large consecutive patient series, 1.5% of lumbar TDRs were removed/revised. Only one revision was related to device failure or wear. Many of the removals/revisions were performed within a month of implantation. Also of note, many occurred within the first 25 TDR cases for individual surgeons, suggesting a learning curve. The low rate of removal/revision in this large institutional experience over a 20-year period provides support for the safety of these devices. <h3>FDA DEVICE/DRUG STATUS</h3> Charite and activL, approved for 1-level (Approved for this indication), ProDisc-L for 1- and 2-level (Approved for this indication), Hybrid, devices other than ProDisc for 2-level, adjacent to prior fusion (Not approved for this indication), All devices other than Charite, ProDisc-L, and activL (Investigational/Not Approved)

134. Lumbar total disc replacement for the treatment of adjacent segment degeneration after lumbar fusion

<h3>BACKGROUND CONTEXT</h3> One of the potential problems associated with lumbar fusion is the development of adjacent segment degeneration. While there may be debate over the incidence and causes of ASD, it does exist and for patients with significant symptoms, merits treatment. There is little information available specifically on the treatment of this condition. <h3>PURPOSE</h3> The purpose of this study was to investigate the outcome of lumbar TDR used to treat adjacent segment degeneration after prior lumbar fusion. <h3>STUDY DESIGN/SETTING</h3> This study was based on retrospective record review combined with a mailing to collect current outcome data. <h3>PATIENT SAMPLE</h3> The study was based on 30 consecutive patients, beginning with first case experience in 2005, who underwent lumbar TDR at one or more levels adjacent to a prior fusion to treat symptomatic disc degeneration unresponsive to nonoperative care. The median number of lumbar spine surgeries prior to TDR was 2. <h3>OUTCOME MEASURES</h3> The outcome measures used in the study included visual analog scales (VAS) assessing back and leg pain, the Oswestry Disability index (ODI), and the occurrence of re-operations. <h3>METHODS</h3> Records of patients undergoing TDR were reviewed and those who had previously undergone lumbar fusion were identified. Charts were reviewed to collect general patient data, surgical details, and clinical outcome measures. Mailings were sent to patients who had not been seen recently in the clinic to collect current outcome data. <h3>RESULTS</h3> The mean follow-up duration after TDR was 76.6 months. A total of 40 TDRs were implanted in the 30 patients. The most frequently operated level was L4-5 above a prior L5-S1 fusion. The VAS back pain and ODI scores improved significantly from pre-TDR to final follow-up (VAS back pain from 7.3 to 4.6, p <0.001 and ODI scores 48.9 to 32.4, p <0.025). VAS leg pain scores improved, but not significantly (4.4 to 3.6). Three patients (10.0%) underwent additional lumbar spinal surgery after the TDR procedure. These included one patient undergoing a discectomy at an upper lumbar level following a fall, one patient underwent multiple surgeries at a remote facility to perform instrumented posterior fusion at the TDR level and the level fused anteriorly prior to the TDR surgery, and the third patient received a spinal cord stimulator after TDR and reported he later had surgery performed remotely to add posterior supplemental fixation at the TDR level due to instability. <h3>CONCLUSIONS</h3> While there is much literature discussing the occurrence and possible mechanisms of lumbar adjacent segment degeneration following lumbar fusion, less information is available on the treatment of this condition. The current study found that TDR can be used effectively for treating adjacent segment degeneration providing the patient is an appropriate candidate for this procedure. In evaluating these patients, particular attention must be paid to the condition of the facet joints to ensure TDR is not contra-indicated. <h3>FDA DEVICE/DRUG STATUS</h3> Charite, ProDisc-L, activL (Not approved for this indication)

P77. What happened to patients who received the Charite lumbar artificial disc?

P77. What happened to patients who received the Charite lumbar artificial disc?

Evaluation of Anterior Lumbar Interbody Fusion Performed Using a Stand-Alone, Integrated Fusion Cage.

Anterior lumbar interbody fusion (ALIF) has been performed for many years. Often, posterior supplemental fixation has been used to provide additional stability to the operated segment. Interbody implants have evolved to incorporate unique designs, polyetheretherketone, integrated screws, and surface texture. With these changes, the need for supplemental posterior fixation has been debated. The purpose of this study was to evaluate the clinical outcome of stand-alone ALIF. A surgery log was reviewed to identify the consecutive series of 58 patients undergoing ALIF using a STALIF stand-alone cage from March 2011 (first case) to December 2018 (minimum 24 months postoperative) with a mean follow-up of 30.6 months. All patients were treated for symptomatic degenerative conditions. Charts were reviewed to collect general patient information, operative data, and patient-reported outcomes, including the Oswestry Disability Index (ODI), visual analog scales (VAS) separately assessing back pain and leg pain, and re-operations. For patients who were not seen recently in clinic for follow-up, current outcome data were collected through mailings. The mean operative blood loss was 52.1 mL. There was a statistically significant improvement in mean ODI scores from 41.7 preoperatively to 21.0 at follow-up (P < 0.01). There was also significant improvement (P < 0.01) in VAS back pain (6.0-2.5) and leg pain (4.1-1.3). Subsequent surgery was performed on 9 patients. Reasons for re-operation were pseudoarthrosis (n = 3), progressive cage subsidence (n = 1), foraminal stenosis at the index level (n = 1), metal allergy reaction (n = 2), adjacent segment degeneration (n = 1), and ongoing pain (n = 1). There were no cases of device failure, vertebral body fracture, or screws backing out of the implant. Stand-alone ALIF was associated with statistically significant improvements in ODI scores, back pain, and leg pain. The re-operation rate for clear pseudoarthrosis or cage subsidence was 6.8%. These results support that stand-alone ALIF produces good outcomes in patients treated for symptomatic disc degeneration while avoiding the use of posterior fixation and its complication risk and cost. The results of this study support that stand-alone ALIF is a viable procedure for the treatment of symptomatic disc degeneration unresponsive in patients who have failed nonoperative care and who do not have specific indications for supplemental posterior instrumentation.

In which cases do surgeons specializing in total disc replacement perform fusion in patients with symptomatic lumbar disc degeneration?

The purpose of this study was to investigate reasons and their frequency for why spine surgeons subspecializing in total disc replacement (TDR) performed lumbar fusion rather than TDR. The study was based on a consecutive series of 515 patients undergoing lumbar TDR or fusion during a 5-year period by three surgeons specializing in TDR. For each fusion patient, the reason for not performing TDR was recorded. TDR was performed in 65.4% (n = 337) of patients and the remaining 34.6% (n = 178) underwent anterior lumbar interbody fusion (ALIF ± posterior instrumentation). Of the 178 fusion patients, the most common reason for fusion was combined factors related to severe degenerative changes (n = 59, 11.5% of the study population). The second most common reason was > Grade 1 spondylolisthesis (n = 32, 6.2%), followed by insurance non-coverage (n = 24, 4.7%), and osteopenia/osteoporosis (n = 13, 2.5%). Fusion patients were significantly older than TDR patients (52.5 vs. 41.6years; p < 0.01). There was no significant difference with respect to gender (41.2% female vs. 43.8% female, p > 0.05) or the percentage of patients with single-level surgery (61.2% vs. 56.7%, p > 0.05). The most common reason for not performing lumbar TDR was related to anatomic factors that may compromise stability of the operated segment and/or TDR functionality. The older age of fusion patients may be related to these factors. This study found that many patients are appropriate candidates for lumbar TDR. However, even among TDR subspecialists, fusion is preferred when there are factors that cannot be addressed with TDR and/or may compromise implant functionality.

Patient with Lumbar Spondylosis and Diskogenic Pain

Diskogenic low back pain (LBP), defined as pain that originates from a damaged vertebral disk, is a common cause of LBP. It is characterized by a three-phase cascade of degeneration marked by dysfunction, instability, and stabilization. A distinct pathologic characteristic of the disks from patients with diskogenic LBP has been found to be the formation of the zones of vascularized granulation tissue, with extensive innervation extending from the outer layer of the annulus fibrosus into the nucleus pulposus along a torn fissure. In addition, there appears to be an association between microbial infection and symptomatic disk degeneration. Low-virulence microorganisms, in particular Propionibacterium acnes, might be causing a chronic low-grade infection in the lower intervertebral disks in some patients. The diagnosis of diskogenic pain is primarily based on clinical manifestations, physical examinations, imaging studies, and provocative diskography. Diskogenic pain should be differentiated from other axial back pain conditions, such as facet arthropathy, sacroiliac joint pain, myofascial strain and pain, vertebral compression fracture, and other, less common conditions. Treatment options should be tailored to individual needs. Early and gradual physical and behavioral therapies are encouraged. Pharmacologic therapy, composed primarily of analgesics, nonsteroidal antiinflammatory drugs, muscle relaxants, and antidepressants, may have modest positive effects. A subset of patients with Modic type I changes in magnetic resonance imaging may benefit antibiotic therapy directed at the infected disks by P. acnes and other low-virulence microorganisms. There is evidence that supports the use of epidural steroid injections and intradiskal injections (methylene blue, ozone, steroids) for diskogenic pain. Additional options include intradiskal biacuplasty, gray ramus communicans nerve blocks/radiofrequency ablation, and intradiskal stem cell injections for disk repair/regeneration, all of which have gained support in clinical trials. These treatment modalities have shown promise to provide equal or even better outcomes compared with surgical spinal fusion or total disk replacement with an artificial disk. This review contains 2 figures and 149 references. Keywords: collagen, diskogenic low back pain (LBP), herniation, intervertebral disk, spondylosis

Current Knowledge and Future Therapeutic Prospects in Symptomatic Intervertebral Disc Degeneration.

Intervertebral disc (IVD) degeneration is the main source of intractable lower back pain, and symptomatic IVD degeneration could be due to different degeneration mechanisms. In this article, we describe the molecular basis of symptomatic IVD degenerative disc diseases (DDDs), emphasizing the role of degeneration, inflammation, angiogenesis, and extracellular matrix (ECM) regulation during this process. In symptomatic DDD, pro-inflammatory mediators modulate catabolic reactions, resulting in changes in ECM homeostasis and, finally, neural/vascular ingrowth-related chronic intractable discogenic pain. In ECM homeostasis, anabolic protein-regulating genes show reduced expression and changes in ECM production, while matrix metalloproteinase gene expression increases and results in aggressive ECM degradation. The resultant loss of normal IVD viscoelasticity and a concomitant change in ECM composition are key mechanisms in DDDs. During inflammation, a macrophage-related cascade is represented by the secretion of high levels of pro-inflammatory cytokines, which induce inflammation. Aberrant angiogenesis is considered a key initiative pathologic step in symptomatic DDD. In reflection of angiogenesis, vascular endothelial growth factor expression is regulated by hypoxia-inducible factor-1 in the hypoxic conditions of IVDs. Furthermore, IVD cells undergoing degeneration potentially enhance neovascularization by secreting large amounts of angiogenic cytokines, which penetrate the IVD from the outer annulus fibrosus, extending deep into the outer part of the nucleus pulposus. Based on current knowledge, a multi-disciplinary approach is needed in all aspects of spinal research, starting from basic research to clinical applications, as this will provide information regarding treatments for DDDs and discogenic pain.

Association between vitamin D receptor gene polymorphism (rs731236) and aggrecan gene VNTR polymorphism with the risk of lumbar intervertebral disc degeneration.

Background:Low back pain is one of the most common causes of referral to physicians. Lumbar disc degeneration (LDD) is the main cause of back pain in different countries. It seems that genetic factors are more effective than environmental factors in the developing of degenerative phenomena. The aim of this investigation, therefore, was to study the association of the aggrecan gene (ACAN) variable number tandem repeat (VNTR) and the vitamin D receptor (VDR) rs731236 (TaqI) polymorphisms, with lumbar intervertebral disc degeneration in a population in the North of Iran.Methods:In this study, 55 patients with symptomatic intervertebral disk degeneration and 55 control subjects were included. VDR gene polymorphism was genotyped by PCR-based RFLP. The isolated DNA was used to genotype the VNTR of ACAN gene via conventional PCR.Results:For VDR gene polymorphism, the CC genotype (OR=5.337, P=0.019) was significantly higher among the patients compared with the controls, revealing a higher frequency of the C allele in patients compared with controls (OR=2.707, P=0.005). The lower number of frequent repetitions in the VNTR aggrecan gene was associated with a six-time increase of lumbar disc degeneration. Also, high BMI can be considered as an independent factor in the incidence of this disease.Conclusion:Aggrecan gene VNTR polymorphism had an association with degeneration of lumbar intervertebral discs that the shorter VNTR repeats increasing the chance of the disc degeneration in this population in the North of Iran. Moreover, an association between the mutant allele (C) of VDR gene TaqI polymorphism and disc degeneration is found.

Revision Surgery for Symptomatic Adjacent Segment Disc Degeneration after Initial Anterior Cervical Fusion: Is ROI-C Better than Plate-Cage Construct?

The optimal revision surgical strategy for patients who develop symptomatic adjacent segment disc degeneration (ASD) is controversial. The risks of intraoperative complications, especially the incidence of dysphagia, were relatively high for revision surgeries. This study was aimed at comparing the efficacy of revision surgery using a traditional plate-cage construct and zero-profile anchored spacer (ROI-C) device in treating symptomatic ASD after initial anterior cervical discectomy and fusion (ACDF) surgery. Forty-two patients who developed symptomatic ASD were retrospectively analyzed and classified into two groups (plate-cage group and ROI-C group). The clinical and radiological results were compared. We further evaluated the complication of dysphagia and dysphagia-related risk factors in these patients. The JOA and NDI scores, C2-7 lordotic angle, and intervertebral space height were significantly improved after revision surgery in both groups. The operative time and intraoperative blood loss both significantly decreased in the ROI-C group. The incidence of postoperative dysphagia was much lower in the ROI-C group than in the plate-cage group (18.75% vs. 57.69%; P = 0.01). The presence of dysphagia after initial surgery (P = 0.003) and revision surgery type (P = 0.01) was significantly related to the presence of dysphagia after revision surgery. These results indicated that both the plate-cage construct and ROI-C are effective in treating symptomatic ASD. However, compared with the traditional plate-cage construct, ROI-C with less operative time, less blood loss, and lower incidence of dysphagia is more suitable. Furthermore, ROI-C should preferably be used for patients who present with dysphagia after initial cervical surgery. This study will provide clinical guidance for spinal surgeons to choose the zero-profile device in treating specific and complicated cases, which will significantly improve the therapeutic efficacy of symptomatic adjacent segment degeneration.