Lumbar Disc Replacement Research Articles

Lumbar Disc Replacement Versus Interbody Fusion: Meta-analysis of Complications and Clinical Outcomes.

Lumbar spinal fusion is a commonly performed operation with relatively high complication and revision surgery rates. Lumbar disc replacement is less commonly performed but may have some benefits over spinal fusion. This meta-analysis aims to compare the outcomes of lumbar disc replacement (LDR) versus interbody fusion (IBF), assessing their comparative safety and effectiveness in treating lumbar DDD. PubMed, Cochrane, and Google Scholar (pages 1-2) were searched up until February 2024. The studied outcomes included operative room (OR) time, estimated blood loss (EBL), length of hospital stay (LOS), complications, reoperations, Oswestry Disability Index (ODI), back pain, and leg pain. Ten studies were included in this meta-analysis, of which six were randomized controlled trials, three were retrospective studies, and one was a prospective study. A total of 1720 patients were included, with 1034 undergoing LDR and 686 undergoing IBF. No statistically significant differences were observed in OR time, EBL, or LOS between the LDR and IBF groups. The analysis also showed no significant differences in the rates of complications, reoperations, and leg pain between the two groups. However, the LDR group demonstrated a statistically significant reduction in mean back pain (p=0.04) compared to the IBF group. Both LDR and IBF procedures offer similar results in managing CLBP, considering OR time, EBL, LOS, complication rates, reoperations, and leg pain, with slight superiority of back pain improvement in LDR. This study supports the use of both procedures in managing degenerative spinal disease.

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.

Assessing lumbar vertebral bone quality: a methodological evaluation of CT and MRI as alternatives to traditional DEXA.

The purpose of this study was to investigate the impact of various methods on the assessment of vertebral bone quality. A consecutive series of 427 candidates for lumbar disc replacement with lumbar DEXA and MRI and/or CT scans were included. Two measurement techniques were used on CTs-a sagittal and axial. From axial images, the upper, mid, and lower portions of each vertebral body were measured. Four MRI vertebral bone quality (VBQ) calculations were generated using separate equations. All CT measures were highly correlated with each other, regardless of measurement or calculation method (range 0.925-0.995). Sagittal measurements were highly correlated with axial (r = 0.928, p < 0.001). CT values were correlated with DEXA (range 0.446-0.534). There was no benefit to measuring multiple axial images of each vertebral body vs. just midbody (r = 0.441 and 0.455, respectively). No MRI VBQ values were highly correlated with DEXA (r = - 0.103, p = 0.045). In receiver operating curve analysis, the area under the curve ranged from 0.539 to 0.558, indicating poor ability of VBQ to identify osteoporosis/osteopenia. CT produced values more closely related to DEXA, while MRI was less reliable for osteoporosis/osteopenia screening. On CT, there was no benefit to making multiple measurements for each vertebral body to calculate a composite. Measuring sagittal CT images produced values similar to axial and required less time. While assessing bone quality from existing images rather than getting an additional DEXA scan is appealing, the methods of measuring these images needs standardization to maximize their utility.

Design of a Novel Kresling Origami Lumbar Disc Replacement for Degenerative Disc Disease

Though it is normal for spinal discs to show signs of wear and deterioration with age, this process may result in degenerative disc disease (DDD), causing pain, stiffness, and even physical deformity. DDD affects 40% of people aged 40 years old and increases to 80% for those aged 80 years or older. Lumbar disc replacements (LDRs) are commonly used as a surgical intervention for DDD. Unfortunately, currently marketed LDRs present a myriad of problems that lead to a clinical failure rate of up to 26% at a two-year follow-up report. Patients with underlying conditions such as diabetes experience even higher rates of clinical failure. Root causes for complications include incorrect sizing of the implant, lack of mobility, and material choices that do not allow for proper integration into the body. Our project proposes a novel design that will replicate the properties of natural lumbar discs and mitigate these complications. This design consists of porous titanium (Ti-6AL-4V)/chitosan sponge composite endplates that can be loaded with compounds to prevent infection and accelerate fusion with the vertebrae surrounding the LDR. A polyurethane Kresling Origami-inspired insert will be sandwiched in between the endplates, allowing the LDR to adjust its size for optimal fitting and provide shock absorption, stability, and mobility to the spinal column. Methods for executing this design are also proposed, along with mechanical and biological tests to be conducted. This paper is the first part in a series of studies that will culminate in assembling and testing the final LDR.

Rates, Predictive Factors, and Adverse Outcomes of Fusion Surgery for Lumbar Degenerative Disorders in Ontario, Canada, Between 2006 and 2015: A Retrospective Cohort Study

The addition of fusion surgery to the decompression for lumbar degenerative disorders remains controversial. The purpose of this study is to compare the rate and outcome of decompression and fusion versus decompression alone. This population-based retrospective cohort study used several linked administrative databases to identify patients who underwent spinal decompression surgery in Ontario, Canada, from 2006 to 2015. Patients who had previous spine surgery, concurrent lumbar disc replacement, or a diagnosis other than degenerative disc disease were excluded. Adjusted logistic regression was used to assess our outcomes. We identified 33,912 patients, of whom 9748 (28.74%) underwent fusion. Overall, fusion rates increased from 27.66% to 31.33% over the study period (P= 0.025). Factors associated with fusion included: older age, female sex, American Society of Anesthesiologists score ≥3, previous total joint replacement, and surgery by an orthopedic surgeon. Fusion surgery was associated with increased odds of 30-day mortality (odds ratio [OR] 1.77, 95% confidence interval [CI] 1.01-3.09; P= 0.046), 30-day (OR 1.94, 95% CI 1.53-2.46; P < 0.0001) and 90-day reoperation (OR 1.66, 95% CI 1.35-2.05; P < 0.0001), and 30-day readmission (OR 1.23, 95% CI 1.02-1.49; P= 0.027) when adjusting for confounding variables. The odds of suffering a complication after fusion and decompression surgery vs. decompression surgery alone were 4.3-fold greater (95% CI 3.78-5.09; P < 0.0001). As compared with decompression alone, spinal fusion for degenerative lumbar disorders is associated with increased odds of adverse outcomes. These findings highlight the need for spine surgeons to consider carefully their indications for fusion procedures in the setting of degenerative spinal disorders.

Long-Term Results of Charité Lumbar Disc Replacement: A 17-Year Follow-Up in a Workers' Compensation Cohort.

Lumbar total disc replacement (TDR) is an alternative to lumbar fusion for the management of degenerative disc disease. This study aims to provide insight into the long-term clinical outcomes of lumbar TDR with a mean follow-up of 17.2 years in a group of workers' compensation patients. A total of 26 workers' compensation patients with radiographically confirmed discogenic low back pain were treated with the Charité total lumbar disc replacement. Visual analog scale (VAS) scores were assessed before and after the surgery. At follow-up, patients were assessed on quality of life, employment, further lumbar spine surgeries, and associated complications. Simple nonparametric statistical analysis was performed by the first author using Microsoft Excel. Sixteen patients (62%) were able to be contacted with a mean follow-up time of 17.2 years. VAS scores at 17 years were significantly lower than their preoperation level. Of those 16 patients, 81% returned to work and worked for an average of 9.1 years after surgery. Additionally, 6 (38%) patients underwent further lumbar spinal surgery, of whom 4 underwent fusions of the adjacent segment. Nearly all patients (94%) were satisfied with the surgery. This study suggests lumbar TDR may be a useful treatment for degenerative disc disease in select workers' compensation patients. Clinically relevant improvements in pain and employment can be achieved with the charite lumbar TDR in the treatment of degenerative disc disease in workers' compensation patients. These results are sustained over the long term.

National trends in the utilization of lumbar disc replacement for lumbar degenerative disc disease over a 10-year period, 2010 to 2019.

BackgroundLumbar fusion (LF) is commonly performed to manage lumbar degenerative disc disease (LDDD) that has failed conservative measures. However, lumbar disc replacement (LDR) procedures are increasingly prevalent and designed to preserve motion in carefully selected patients.MethodsA retrospective cohort study was performed using the National Inpatient Sample (NIS), queried from 2010 to 2019 to identify patients undergoing single and double-level LF or LDR with a diagnosis of LDDD using International Classification of Diseases (ICD) 9th (ICD-9) and 10th (ICD-10) revision diagnostic and procedure codes. Propensity score matching (PSM) with a ratio of 2:1 was performed. All cost estimates reflect reported hospital costs adjusted to December 2019 United States Dollars.ResultsA total of 1,129,121 LF cases (99.3%) and 8,049 LDR cases (0.7%) were identified, with 364,637 (32.3%) and 712 (8.8%) comprising two-level surgeries, respectively. 1,712 LDRs were performed in 2010 (1.27% of all), decreasing to 565 in 2013 (0.52%), and increased slightly to 870 in 2019 (0.74%). LDR patients were significantly more likely to be younger (mean age 41.2 vs. 57.1, P<0.001) and healthier (mean ECI 0.88 vs. 1.80, P<0.001). On matched analysis, LDR hospital costs were $4,529 less (P<0.001) and length of stay was 0.65 days shorter (P<0.001) than LF patients. LDR patients had lower rates of any complication (7.0% vs. 13.2%, P<0.001), neurologic complication (3.0% vs. 4.2%, P=0.006), and blood transfusion (3.1% vs. 8.1%, P<0.001) compared to LF patients.ConclusionsThe prevalence of LDR procedures decreased from 2010–2017 but began to increase again in 2018 and 2019. Single-level LDR was associated with reduced costs and length of stay (LOS), and lower rates of blood transfusion compared to LF in patients with LDDD.

129. National trends in the utilization of lumbar disc replacement for lumbar degenerative disc disease over a 10-year period, 2010 to 2019

<h3>BACKGROUND CONTEXT</h3> In the treatment of lumbar degenerative disc disease (DDD) that has failed conservative measures, lumbar fusion (LF) remains the gold standard. Approved in 2004, lumbar disc replacement (LDR) is designed to preserve motion. Initial studies showed LDR was used in 2.7% of surgeries for DDD and spondylosis. <h3>PURPOSE</h3> We aim to analyze the trends, complications and costs associated with LDR compared to LF using a large national database. <h3>STUDY DESIGN/SETTING</h3> Restrospective, administrative database. <h3>PATIENT SAMPLE</h3> National Inpatient Sample, 2010-2019. <h3>OUTCOME MEASURES</h3> Cost, length of stay, discharge destination, index hospitalization complications. <h3>METHODS</h3> The National Inpatient Sample (NIS) was queried from 2010 to 2019 to identify patients undergoing single and double- level LF and LDR with a diagnosis of lumbar DDD using ICD-9 and ICD-10 diagnostic and procedure codes. Revision procedures were excluded. Propensity score matching (PSM) with a ratio of 2:1 was performed to compare health care utilization metrics and index hospital complications for patients undergoing single-level LF or LDR. <h3>RESULTS</h3> A total of 1,129,121 LF cases (99.3%) and 8,049 LDR cases (0.7%) we identified during the study period, with 364,637 (32.3%) and 712 (8.8%) comprising two-level procedures, respectively. 1,712 LDRs were performed in 2010 (1.27% of all), decreasing to 565 in 2013 (0.52%), and increased slightly to 870 in 2019 (0.74%). For single-level procedures, the proportion of LDR cases decreases from 1.41% in 2010 to 0.66% in 2013 (p <0.001), but then increased gradually to 1.17% in 2019 (p <0.001 for trend). The proportion of two-level LF and LDR procedures increased significantly over the study period from 15.7% in 2010 to 45.5% in 2019 (p <0.001 for trend). LDR patients were significantly more likely to be younger (mean age 41.2 vs 57.1, p <0.001), healthier (mean ECI 0.88 vs 1.80, p <0.001) and male (57.5% vs 47.1%, p <0.001). LDR patients were also more likely to have procedures paid for by private insurance (55.8% vs 43.7%, p <0.001) and reside in higher income areas (top quartile 30.0% vs 23.2%, p <0.001). On PSM analysis, a total of 1,343 single-level LDR patient records were matched to 2,686 single-level LF patient records, and 141 two-level LDR patient records were matched to 282 two-level LF patient records. Single-level LDR patients had significantly shorter LOS (2.45 vs 3.10 days, p <0.001), lower likelihood of discharge to facility (1.7% vs 3.4%, p=0.003), and lower costs overall ($27,714 vs $32,242, p <0.001) compared to matched LF patients. Single-level LDR patients had significantly lower rates of any complication (7.0% vs 13.2%, p <0.001), blood transfusion (3.1% and 8.1%, p <0.001) and neurologic complication (3.0% vs 4.8%, p=0.006). There were no differences with regard to VTE, pneumonia, renal, would or pulmonary complications. With regard to two-level procedures, there were no differences with regard to LOS and discharge to facility (p=0.38 and 0.21, respectively), while overall costs were significantly higher for LDR patients compared to LF ($53,270 to $44,721, p=0.005). There were no differences in rates of index hospitalization complications for two-level procedures. <h3>CONCLUSIONS</h3> The utilization of LDR procedures decreased from 2010-2017 but began to increase again in 2018 and 2019. After adjusting for demographic, medical and hospital variables, single-level LDR was associated with reduced costs and LOS, and lower rates of blood transfusion compared to single-level fusion in patients with lumbar DDD. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Evaluating the Impact of Modic Changes on Operative Treatment in the Cervical and Lumbar Spine: A Systematic Review and Meta-Analysis.

Modic changes (MCs) are believed to be potential pain generators in the lumbar and cervical spine, but it is currently unclear if their presence affects postsurgical outcomes. We performed a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. All studies evaluating cervical or lumbar spine postsurgical outcomes in patients with documented preoperative MCs were included. A total of 29 studies and 6013 patients with 2688 of those patients having preoperative MCs were included. Eight included studies evaluated cervical spine surgery, eleven evaluated lumbar discectomies, nine studied lumbar fusion surgery, and three assessed lumbar disc replacements. The presence of cervical MCs did not impact the clinical outcomes in the cervical spine procedures. Moreover, most studies found that MCs did not significantly impact the clinical outcomes following lumbar fusion, lumbar discectomy, or lumbar disc replacement. A meta-analysis of the relevant data found no significant association between MCs and VAS back pain or ODI following lumbar discectomy. Similarly, there was no association between MCs and JOA or neck pain following ACDF procedures. Patients with MC experienced statistically significant improvements following lumbar or cervical spine surgery. The postoperative improvements were similar to patients without MCs in the cervical and lumbar spine.

A cross-sectional analysis of 284 complications for lumbar disc replacements from medical device reports maintained by the United States Food and Drug Administration

BACKGROUND CONTEXTLumbar disc replacement (LDR) is a motion sparing procedure for degenerative disc disease. When compared to lumbar fusion, this procedure may reduce complications, reoperations, operative time, and length of stay. However, the extent of overall complications related to LDR has not been well defined in the literature. PURPOSEDemonstrate the complication profile of popular LDR implants reported to the Food and Drug Administration (FDA). STUDY DESIGNRetrospective database review. PATIENT SAMPLENationwide database of reported complications related to LDR products from patients throughout the country. OUTCOME MEASURESComplications related to LDR. METHODSData files from January 1, 2004 to April 1, 2021 were queried using the publicly accessible Manufacturer and User Facility Device Experience (MAUDE) database and Alternative Summary Reporting program. Three LDR (“Charité,” “Prodisc-L,” and “Activ L”) products were analyzed for complications. Data collected included the date the reports were received by the FDA, the type of complication, complication event description, and the source of the report. The complication event description was utilized to determine the completion of the investigation. Entries with insufficient information were excluded. Complications were further divided into two categories, device and non-device related. RESULTSA total of 431 complication entries were found between January 1, 2004, and April 1, 2021. After screening for duplicates and events with insufficient information there were 284 total complications. The total complications were then further divided into implant and non-implant related. The five most common overall complications were lumbar pain (49 entries, 17.25%), migration of implant (42 entries, 14.78%), polyethylene dislodged (37 entries, 13.0%), insertion of device problem (37 entries, 13.0%), device handling problem (12 entries, 4.22%). The most common implant related complication, along with the number of MAUDE entries for each implant was migration of implant for Charité (n=6); Migration of implant for ActivL (n=24); Polyethylene dislodged for ProdiscL (n=32). Of the 284 total complications analyzed, 86 (30.28%) of the entries were deemed “investigation completed.” The majority of reports were submitted from the manufacturer and company representative (66.2%, 14.8 % respectively). There were no entries related to LDR within the Alternative Summary Reporting search. CONCLUSIONSThis study outlined the complications of LDR implants from the MAUDE database which have not always been highlighted in previously published studies. The findings of this study provide insight into the potential targets for improvement in future LDR design and surgical techniques to reduce complications and ensure the safe utilization of these implants.

The Lateral Approach in Lumbar Total Disc Replacement: A Literature Review

Lumbar disc replacement has become an area of interest for many practicing spine surgeons. As newer technology emerges focusing on motion sparing devices, novel techniques are being employed to better serve patients and increase post-operative outcomes.

Long-term clinical and radiological outcomes after total lumbar disc replacement at the lumbosacral junction

The study objective is to analyze long-term clinical and radiological outcomes in patients after performing total lumbar disc replacement at the level of the lumbosacral junction.Materials and methods. A multicenter retrospective observational cohort study was performed. The study included medical records of patients who underwent total lumbar disc replacement at the level of the lumbosacral junction. Both clinical and instrumental parameters were assessed. According to the eligibility criteria, 93 patients were included in the study (38 men, 55 women, mean age 39.9 ± 7.5 years). The average postoperative observation period for the respondents was 33.4 ± 9.5 months.Results. The severity of pain in the lumbar spine on a visual analogue scale significantly decreased (from 7.3 ± 2.5 to 1.9 ± 2.2 cm, p &lt;0.001). The indicators of the quality of life according to the Oswestry Disability Index and according to the Short Form-36 scale (including the mental and physical components) of the studied group of respondents significantly improved (from 43.4 ± 17.6 to 18.9 ± 16.0 %, р &lt;0.001 and from 30.8 ± 8.5 to 52.3 ± 12.4 %, p &lt;0.001, respectively). From the 12th month of observation of the respondents, a significant decrease in the values of the range of motions of the operated segment was noted from 5.3 ± 3.2° to 4.1 ± 3.6° (p &lt;0.009). Also, from the 12th month of postoperative observation, a slight decrease in the values of the range of motions of the adjacent segment from 8.6 ± 4.1° to 7.8 ± 3.8° (p &gt;0.05) was verified. The value of global lumbar lordosis after the installation of a lumbar intervertebral disc prosthesis at the level of the lumbosacral junction significantly increased from 49.1 ± 4.8° to 55.6 ± 5.5° (p &lt;0.001). Intervertebral disc prostheses with a lordotic angle of 10° reliably positively correlate with an increase in the values of segmental lordosis, in contrast to implants with an angle of 6° (rS = 0.86, p = 0.04). The severity of pain in the lumbar spine according to visual analogue scale and the range of motion of the operated segment has a significant negative correlation in the late periods of postoperative follow-up (24 and 36 months, rS = -0.74, p = 0.015).Conclusion. The total lumbar disc replacement technique is an effective method of surgical treatment of patients with degenerative diseases of the intervertebral discs of the lumbosacral spine, including at the level of the lumbosacral junction.

Clinical-Instrumental Results and Analysis of Functional Activity Restoration in Professional Athletes After Lumbar Total Disk Replacement

To analyze the clinical and biomechanical outcome of professional athletes after lumbar total disk replacement, with a focus on restoration of the functional activity. This nonrandomized retrospective single-center study included 11 professional athletes who underwent lumbar disc replacement surgery using the prosthesis M6-L (Spinal Kinetics, Schaffhausen, Switzerland). The average postoperative follow-up was 3.18 ± 1.14 years. The following outcomes were evaluated: intensity of pain in the lumbar spine and lower limbs, Oswestry Disability Index, Short-Form 36, complications, time of return to previous sports activity, range of movement, degree of lumbar lordosis, degenerative changes of the adjacent levels, and degree of heterotopic ossification. The operated patients reported significant decrease of pain on visual analog scale (P < 0.001) as well as significant improvement of Oswestry Disability Index (P= 0.001) and Short-Form 36 (P < 0.001). For the duration of follow-up, the patients maintained segmental range of motion at L4-L5 (P= 0.04) and L5-S1 (P= 0.03) levels. There was also some statistically insignificant increase of global lumbar lordosis (P= 0.84). We did not identify any significant degeneration of the adjacent intervertebral disks (P > 0.05) or progression of the facet joint degenerative changes at the implantation level and in the adjacent segments (P > 0.05). One patient (9.1%) developed grade I heterotopic ossification 5 years after surgery and in 1 patient (9.1%), a lesion of superior hypogastric plexus was recorded. The average time of return to previous sports activity was 9.72 ± 3.03 weeks. Total lumbar disc replacement using M6-L prosthesis in professional athletes made it possible to achieve statistically significant reduction of pain and facilitated early return to normal sports activities. In our opinion, preservation of movement of the operated lumbar segment can help to reduce the mechanical stress with beneficial impact on the rate of degeneration of the adjacent level.

Revision Surgery of Total Lumbar Disk Replacement: Review of 48 Cases.

This was a retrospective clinical review. The objective of this study was to analyze failure mechanisms after total lumbar disk replacement (TDR) and surgical revision strategies in patients with recurrent low back pain (LBP). Several reports indicate that TDR revision surgery carries a major risk and that it should not be recommended. The clinical results of posterior instrumented fusion using the prosthesis like an interbody cage have not been well analyzed. From 2003 to 2018, 48 patients with recurrent LBP after TDR underwent revision surgery. The average age was 39 years (24-61 y). The mean follow-up was 100.4 months (24.6-207.7 mo). Clinical data, self-assessment of patient satisfaction, and Oswestry Disability Index collected at each clinical control or by phone call for the older files and radiologic assessments were reviewed. The surgical revision strategy included posterior fusion in 41 patients (group A) and TDR removal and anterior fusion in 7 patients (group B), of which 6 patients had an additional posterior fixation. Facet joint osteoarthritis was associated with TDR failure in 85%. In 68% the position of the prosthesis was suboptimal. Range of motion was preserved in 25%, limited in extension in 65%, and limited in flexion in 40%. Limited range of motion and facet joint osteoarthritis were significantly related (P=0.0008). The complication rate in group B was 43% including iliac vein laceration. Preoperative and 2-year follow-up Oswestry Disability Index were 25.5 and 22.0, respectively, in group A versus 27.9 and 21.3 in group B. Posterior osteoarthritis was the principal cause of recurrent LBP in failed TDR. The anterior approach for revision carried a major vascular risk, whereas a simple posterior instrumented fusion leads to the same clinical results. Level IV.

2021 Position Statement From the International Society for the Advancement of Spine Surgery on Cervical and Lumbar Disc Replacement.

Cervical and lumbar degenerative disc disease are well-known causes of neck and back pain and associated radiculopathy in spine patients. The estimated 1-year incidence rate of neck pain and any episode of lower back pain is 10.4% to 21.3%[1][1],[2][2] and 1.5% to 36%,[3][3] respectively. Previous

Novel Total Nucleus Replacement Using Spherical Magnetic Beads: A Biomechanical Study

Objective: Lumbar Degenerative Disc Disease is a potential cause of spinal instability. Surgical techniques such as arthrodesis or arthroplasty are implemented to restore the stability to the spine. Both a fusion and a disc replacement are substantially invasive. A lumbar disk replacement is typically done via retroperitoneal or Trans peritoneal approach. With increasing number of symptomatic levels, the disk replacement becomes incrementally more invasive, with a potential for a significant blood loss, injury to great vessels, injury to abdominal viscera, weakening of abdominal wall, etc. There is no minimally invasive way to perform a disk replacement either at one or multiple levels. Our goal was to evaluate the feasibility of a novel and less invasive total nucleus replacement using magnetic spherical beads in a cadaver-based multidirectional bending flexibility model. We aimed to assess the ability of the beads to restore stability to a spine segment. We hypothesized that the beads would increase stability during flexion and extension motions. Methods: Three fresh-frozen, human cadaveric L2-L3 segments were used. We performed multidirectional flexibility tests in six directions, under intact, nucleotomy and bead insertion conditions. We measured the ranges of motions, the neutral zone and the elastic zone. Results: There was statistically significantly more flexion-extension range of motion, neutral zone and elastic zone observed upon nucleotomy than during intact condition. Bead insertion statistically significantly reduced the neutral zone observed after nucleotomy, during flexion and extension loading. Conclusion: We conclude that our novel total nucleus replacement is capable of restoring the stability to spine motion segments during flexion and extension motions, by means of adjustments to their neutral zones.

150. Outpatient vs inpatient anterior lumbar surgery: a multisite, comparative analysis of patient safety measures

BACKGROUND CONTEXT The frequency and complexity of spinal surgery performed in an outpatient setting has been steadily increasing in the past decade. However, data on the safety and efficacy of most spinal procedures adapted to the outpatient setting is lacking. The few studies that have reviewed specific outpatient procedures have mostly focused on anterior cervical surgery, and have drawn conflicting conclusions. To our knowledge, there is no published literature on the feasibility, safety and effectiveness of anterior lumbar surgery (fusions and disc replacements) in an outpatient setting. PURPOSE The purpose of this study is to evaluate the safety and efficacy of outpatient anterior lumbar procedures compared to procedures done at an inpatient setting in a matched cohort of patients. STUDY DESIGN/SETTING This study is a retrospective matched cohort study of patients who underwent an anterior lumbar interbody fusion (ALIF) or a lumbar artificial disc replacement (LADR) at an inpatient facility, compared to a free-standing ambulatory surgery center. PATIENT SAMPLE Consecutive adult patients of several orthopedic and neurosurgical spine surgeons, who underwent elective stand-alone ALIF or LADR or a hybrid of fusion and disc replacement, at either an inpatient tertiary care facility or an outpatient surgical center were studied. A minimum of 90-day follow-up was required. OUTCOME MEASURES Reoperation rates, readmission rates, 90-day complication rates, and length-of-stay data were collected and compared between the two groups. Complications that were specifically assessed included neurological injury, durotomy, vascular injuries, bowel injuries, postoperative ileus, epidural or retroperitoneal hematomas, postoperative urinary retention, urinary tract infections, deep vein thrombosis (DVT), pulmonary embolism (PE), cardio-pulmonary complications, intractable pain, surgical site infection, and death. METHODS Medical records of 231 consecutive patients who underwent ALIF or LADR procedures between 2016-2019 were reviewed. The inpatient and outpatient cohorts were matched with regards to age, sex, body mass index (BMI), and medical comorbidities. Length of stay, complication data, reoperations, and readmissions were recorded and compared between the groups. RESULTS A total of 124 (54%) inpatient and 107 (46%) outpatient patients were reviewed for this study. The two groups had similar baseline characteristics. While there was a trend toward fewer complications, reoperations and readmission for the outpatient cohort, the differences were not statistically significant. The overall 90-day complication rate was 5.6% for the inpatient cohort, and 0.9% for the outpatient cohort. Of the patients in the inpatient cohort, 3.2% were re-admitted within 90 days, compared to 1.9% of those in the outpatient cohort. Reoperation rate was 1.6% for the inpatient cohort. No patient from the outpatient cohort required reoperation. The average hospital stay was 56.9 hours, compared to 5.2 hours at the ambulatory surgery center. CONCLUSIONS There were no statistically significant differences between the 90-day complication and reoperation rates between anterior lumbar procedures performed in an inpatient vs outpatient setting in a matched cohort of patients. Furthermore, the overall 90-day readmission rates were lower for outpatients than for inpatients. Our results support the conclusion that anterior lumbar procedures including 1- and 2-level ALIF and LADR procedures can be performed safely in an outpatient setting. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Lumbar and cervical viscoelastic disc replacement: Concepts and current experience.

The ideal lumbar and cervical discs should provide six degrees of freedom and tri-planar (three-dimensional) motion. Although all artificial discs are intended to achieve the same goals, there is considerable heterogeneity in the design of lumbar and cervical implants. The “second generation total disc replacements” are non-articulating viscoelastic implants aiming at the reconstruction of physiologic levels of shock absorption and flexural stiffness. This review aims to give an overview of the available implants detailing the concepts and the functional results experimentally and clinically. These monobloc prostheses raise new challenges concerning the choice of materials for the constitution of the viscoelastic cushion, the connection between the components of the internal structure and the metal endplates and even the bone anchoring mode. New objectives concerning the quality of movement and mobility control must be defined.

Long-Term Residual-Mobility and Adjacent Segment Disease After Total Lumbar Disc Replacement.

Study Design:Retrospective cohort study.Objectives:Total disc replacement (TDR) has been introduced in order to preserve segmental motion and thus reduce adjacent segment disease (ASD) as seen after spinal fusion. However, it is uncertain whether these presumed beneficial effects remain. The aim of this study was to evaluate the long-term incidence of ASD and residual-mobility in relation to clinical outcome.Methods:A total of 210 patients treated with lumbar TDR for degenerative disc disease were invited for follow-up. ASD was reported in case of severe degeneration in an adjacent disc at latest follow-up, or if an increase in disc degeneration was observed in these adjacent segments as compared to direct postoperative radiographs. Residual-mobility of the TDR was defined as a minimal rotation of 4.6° on flexion-extension radiographs. Patient-reported outcome measures were obtained.Results:Fifty-seven patients (27.1%) were lost to follow-up. In 32 patients (15.3%) a revision by spinal fusion had been performed. In 20 patients this revision had occurred ≥5 years after TDR and were included. Consequently, 141 patients were available for analysis (mean follow-up of 16.7 years). Residual-mobility was noted in 38.0%. No significant associations were observed between residual-mobility and the occurrence of ASD, or with clinical outcome. In addition, ASD and clinical outcome were not related either.Conclusions:It appears that long-term preservation of motion after TDR is met for only a third of patients. However, residual-mobility is not associated with the occurrence of ASD, and both residual-mobility and ASD do not appear to be related to long-term clinical outcome.

A review on the current state of ball-on-socket type artificial lumbar disc prosthesis

Total lumbar disc replacement is an alternative to interbody fusion for the effective treatment of symptomatic degenerative disc disease. This paper reviewed the history of ball-on-socket type artificial lumbar disc (ALD) prosthesis, which is a typical ALD prosthesis and summarized the ALD prosthesis research progress, according to different materials such as metal-on-metal, metal-on-polymer, and polymer-on-polymer prosthesis. The structural design factors of ball-on-socket type ALD prosthesis were analyzed and its prospect of development was also presented. The purpose of this paper is to provide a theoretical reference for the design of the ball-on-socket ALD prosthesis by reviewing the current state of ball-on-socket type ALD prosthesis.