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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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. CLINICAL RELEVANCE: 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.

Minimally Invasive Revision of Luque Plate Instrumentation: A Case Report.

Extension of existing spinal fusions may necessitate the removal of or linkage to prior constructs. Knowledge of previously placed instrumentation is critical to success in these revision scenarios. The Luque spinal instrumentation system, developed in the late 1980s, is a legacy pedicle screw and plate system that may be encountered during revision operations today. A 67-year-old male with a remote history of L4-S1 fusion with Luque instrumentation presented with bilateral lower extremity neurogenic claudication due to adjacent segment disease at L3-4. Decompression and extension of fusion to the L3-4 level were performed using minimally invasive techniques. Of note, posterior instrumentation was extended by removing prior L4 pedicle screws with a 7 mm female hexagonal driver through tubular retractors, leaving the Luque plates in place, placing modern pedicle screws at L4 (through the plates) and L3, and linking these with standard rods. The surgery and post-operative course were uncomplicated, and the patient experienced complete resolution of his pre-operative claudication symptoms. Extension of prior Luque plate instrumented fusion can be accomplished minimally invasively without removing the plates themselves, resulting in greater operative efficiency and less surgical morbidity.

Collagen Matrix Inlay Graft for Management of Incidental Durotomy During Full-Endoscopic Lumbar Spine Surgery: Technique and Case Series.

BACKGROUND: Endoscopic spine surgery (ESS) has a reduced rate of incidental durotomy (ID) compared with open spine surgery. However, there are unique challenges regarding the management of ID in ESS due to the single, deep, narrow working corridor and aqueous environment. Here, we present a collagen matrix inlay graft technique for the management of ID encountered during ESS. METHODS: Three patients were identified via medical record review of full ESS where an intraoperative ID was encountered. These were all addressed endoscopically. All surgeries were performed by a single surgeon in the years 2019 to 2023. Patient, operative, and postoperative details, including patient-reported outcomes, were recorded. Briefly, the collagen matrix inlay graft technique included introducing a segment of collagen matrix into the surgical field and manipulating the collagen matrix so that it passed through the durotomy and resided within the dura, plugging the hole. RESULTS: Three IDs were identified out of a total of 295 eligible cases (1.02%). The IDs measured 2 to 2.5 mm in length. For these 3 patients, the duration of hospital stay ranged from 172 to 1,068 minutes. No patients exhibited signs or symptoms of cerebrospinal fluid leak at any postoperative timepoint. At the 6-week postoperative visit, all patients had achieved the minimum clinically important difference in Oswestry Disability Index, and all patients with available visual analog scale scores for leg and low back pain had achieved the cutoff for the minimum clinically important difference. CONCLUSIONS: We presented 3 cases of ID during uniportal full ESS who were repaired using a collagen matrix inlay technique. Prolonged bed rest was avoided, and all patients achieved excellent clinical outcomes without further complication. This technique may also be appropriate for other minimally invasive spine surgery techniques. CLINICAL RELEVANCE: ID is a common and undesirable complication of degenerative lumbar spine surgery. Endoscopic ID repair techniques provide an option to avoid conversion to open or tubular surgery for the management of ID.

Preservation of Motion in Spine Surgery.

The number of spinal procedures and spinal fusions continues to grow. Although fusion procedures have a high success rate, they have inherent risks such as pseudarthrosis and adjacent segment disease. New innovations in spine techniques have sought to eliminate these complications by preserving motion in the spinal column. Several techniques and devices have been developed in the cervical and lumbar spine including cervical laminoplasty, cervical disk ADA, posterior lumbar motion preservation devices, and lumbar disk ADA. In this review, advantages and disadvantages of each technique will be discussed.

Learning curve for endoscopic posterior cervical foraminotomy.

PURPOSE: While anterior cervical discectomy and fusion as well as cervical disk arthroplasty are gold standard treatments for the surgical treatment of cervical radiculopathy, posterior endoscopic cervical foraminotomy (PECF) as a substitute procedure is gaining popularity. To date, studies investigating the number of surgeries needed to achieve proficiency in this procedure are lacking. The purpose of the study is to examine the learning curve for PECF. METHODS: The learning curve in operative time for two fellowship-trained spine surgeons at independent institutions was retrospectively assessed for 90 uniportal PECF procedures (PBD: n = 26, CPH: n = 64) performed from 2015 to 2022. Operative time was assessed across consecutive cases using a nonparametric monotone regression, and a plateau in operative time was used as a proxy to define the learning curve. Secondary outcomes assessing achievement of endoscopic prowess before and after the initial learning curve included number of fluoroscopy images, visual analog scale (VAS) for neck and arm, Neck Disability Index (NDI), and the need for reoperation. RESULTS: There was no significant difference in operative time between surgeons (p = 0.420). The start of a plateau for Surgeon 1 occurred at 9 cases and 111.6 min. The start of a plateau for Surgeon 2 occurred at 29 cases and 114.7 min. A second plateau for Surgeon 2 occurred at 49 cases and 91.8 min. Fluoroscopy use did not significantly change before and after surmounting the learning curve. The majority of patients achieved minimally clinically important differences in VAS and NDI after PECF, but postoperative VAS and NDI did not significantly differ before and after achieving the learning curve. There were no significant differences in revisions or postoperative cervical injections before and after reaching a steady state in the learning curve. CONCLUSION: PECF is an advanced endoscopic technique with an initial improvement in operative time that occurred after as few as 8 cases to as many as 28 cases in this series. A second learning curve may occur with additional cases. Patient-reported outcomes improve following surgery, and these outcomes are independent of the surgeon's position on the learning curve. Fluoroscopy use does not change significantly along the learning curve. PECF is a safe and effective technique that current and future spine surgeons should consider as part of their armamentarium.

Cervical Disk Arthroplasty and Range of Motion at 7 Years: Impact on Adjacent Level Degeneration.

STUDY DESIGN: Secondary analysis of data collected in a prospective, randomized, noninferiority Food and Drug Administration (FDA) Investigational Device Exemption (IDE) clinical trial. OBJECTIVE: The objective of this study was to evaluate the impact of range of motion (ROM) following single-level cervical disk arthroplasty (CDA) on the development of radiographic adjacent level degeneration (ALD). SUMMARY OF BACKGROUND DATA: The rationale for CDA is that maintenance of index-level ROM will decrease adjacent level stresses and ultimately reduce the development of ALD compared with anterior cervical discectomy and fusion. However, little information is available on the impact of hypermobility on the development of ALD after CDA. MATERIALS AND METHODS: Radiographic assessments were evaluated for index-level flexion-extension ROM and ALD. Continuous data was assessed using 1-way analysis of variance. The relationship between ALD progression and ROM was evaluated using χ 2 tests. The α was set at 0.05. RESULTS: More ALD progression was observed after anterior cervical discectomy and fusion than CDA ( P =0.002 at the superior and P =0.049 at the inferior level). Furthermore, there was an association between ALD progression and ROM ( P =0.014 at the superior level and P =0.050 at the inferior level) where patients with mid-ROM after CDA experienced the lowest frequency of ALD progression at the superior and inferior levels. Patients with the lowest and highest ROM after CDA experienced a greater increase in ALD score at the inferior level ( P =0.046). Sex and age were associated with ROM groups ( P =0.001 and 0.023, respectively). CONCLUSIONS: While maintenance of index-level ROM is protective after CDA, patients with the highest ROM after CDA have similar rates of ALD progression to the lowest ROM and greater increases in ALD compared with mid-ROM after CDA. High ROM after CDA may contribute to ALD progression.

Review of Prospective Trials for Degenerative Cervical Myelopathy.

Degenerative cervical myelopathy (DCM) is the leading cause of spinal cord dysfunction in adults. DCM refers to a collection of degenerative conditions that cause the narrowing of the cervical canal resulting in neurological dysfunction. A lack of high-quality studies and a recent increase in public health awareness has led to numerous prospective studies evaluating DCM. Studies evaluating the efficacy of surgical intervention for DCM can be characterized by the presence (comparative) or absence (noncomparative) of a nonoperative control group. Noncomparative studies predominate due to concerns regarding treatment equipoise. Comparative studies have been limited by methodological issues and have not produced consistent findings. More recent noncomparative studies have established the safety and efficacy of surgical intervention for DCM, including mild myelopathy. The optimal surgical intervention for DCM remains controversial. A recent randomized clinical trial comparing dorsal and ventral techniques found similar improvements in patient-reported physical function at early follow-up. Recent prospective studies have enriched our understanding of DCM and helped guide current treatment recommendations.

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

PURPOSE: 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. METHODS: 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. RESULTS: 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. 41.6 years; 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). CONCLUSION: 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.

Robotic-Assisted Revision Spine Surgery.

As the surgical treatment of spinal degenerative conditions increases, more patients will ultimately require revision spine surgery. Revision spine surgery is more technically demanding than primary surgery with increased complication rates and variable clinical outcomes. The freehand placement of pedicle screws into a previously operated and/or fused level is more difficult due to the altered anatomic landmarks and/or bone loss. Additional benefit of robotic spine surgery is appreciated during such revision spine surgical procedures with unusual anatomic considerations, whereby the preoperative planning using robotic planning software and computer-assisted robotic guidance play a crucial role in assisting the surgeon to "visualize the invisible." We highlight 3 roles of this technology in 3 cases: planning strategic osteotomies, redrilling of screw holes, and insertion of revision screws in previously operated thoracolumbar and cervical spine regions.

Can Robotic Spine Surgery Become the Standard of Care?

Concerns regarding traditional techniques led to the development of robotic systems to facilitate the safe and accurate placement of pedicle screws. The Mazor Spine Assist was the first robotic spine surgery (RSS) platform to receive US Food and Drug Administration approval in 2004. Since then, there has been a steady increase in the application of RSS with several additional iterations of the Mazor platform and other competing systems receiving approval. As the indications, potential benefits, and utilization of RSS continue to expand, the question naturally arises as to whether RSS will eventually become the standard of care for spine surgery. In this article, we review the available evidence and experience with RSS and discuss the potential for RSS to become the medical standard of care.

The Incidence of Subsequent Cervical Spine Surgery after Cervical Disc Arthroplasty, a Minimum Two-year Follow-up.

To identify the risk factors and incidence of subsequent cervical spine surgery in patients undergoing primary cervical disc arthroplasty (CDA). We analyzed the 2005-2015 NYS SPARCS database. Patients were longitudinally followed to determine the incidence of re-operation. Univariate and Multivariate analyses were used to identify demographic risk factors. Eight-hundred and thirty-five CDA patients had a cervical spine re-operation rate of 7.5%; 4.4% re-operation rate at two-year follow-up. The most common cervical re-operation was a primary anterior cervical discectomy and fusion (ACDF) (76.2%). Patients who underwent re-operation were more likely to be younger (p = 0.034) and female (p = 0.007). Logistic regression analysis found only female sex to have increased odds of re-operation (odds ration = 2.10, 95% confidence interval 1.21-3.63). There was a 4.4% rate of subsequent cervical spine surgery following CDA at 2 years and a 7.5% rate of subsequent cervical spine surgery. The most common cervical spine procedure following CDA was ACDF. Female sex was the only patient demographic factor to significantly influence the odds of cervical spine re-operation. (Journal of Surgical Orthopaedic Advances 31(1):007-011, 2022).

Robotic Spine Surgery: Past, Present, and Future.

STUDY DESIGN: Systematic review. OBJECTIVE: The aim of this review is to present an overview of robotic spine surgery (RSS) including its history, applications, limitations, and future directions. SUMMARY OF BACKGROUND DATA: The first RSS platform received United States Food and Drug Administration approval in 2004. Since then, robotic-assisted placement of thoracolumbar pedicle screws has been extensively studied. More recently, expanded applications of RSS have been introduced and evaluated. METHODS: A systematic search of the Cochrane, OVID-MEDLINE, and PubMed databases was performed for articles relevant to robotic spine surgery. Institutional review board approval was not needed. RESULTS: The placement of thoracolumbar pedicle screws using RSS is safe and accurate and results in reduced radiation exposure for the surgeon and surgical team. Barriers to utilization exist including learning curve and large capital costs. Additional applications involving minimally invasive techniques, cervical pedicle screws, and deformity correction have emerged. CONCLUSION: Interest in RSS continues to grow as the applications advance in parallel with image guidance systems and minimally invasive techniques. IRB APPROVAL: N/A.

Robotic-guided placement of cervical pedicle screws: feasibility and accuracy.

INTRODUCTION: It has been shown that pedicle screw instrumentation in the cervical spine has superior biomechanical pullout strength and stability. However, due to the complex and variable anatomy of the cervical pedicles and the risk of catastrophic complications, cervical pedicle screw placement is not widely utilized. STUDY DESIGN: A retrospective, consecutive patient review. OBJECTIVE: To review and report our experience with robotic guided cervical pedicle screw placement. METHODS: We retrospectively reviewed preoperative and postoperative CT scans of 12 consecutive patients who underwent cervical pedicle screw fixation with robotic guidance. Screw placement and deviation from the preoperative plan were assessed using the robotic system's planning software by fusing the preoperative CT (with the planned cervical pedicle screws) to the post-op CT. This process was carried out by manually aligning the anatomical landmarks on the two CTs. Once a satisfactory fusion was achieved, the software's measurement tool was used manually to compare the planned vs. actual screw placements in the axial, sagittal and coronal planes within the instrumented pedicle in a resolution of 0.1 mm. Medical charts were reviewed for technical issues and intra-operative complications. RESULTS: Eighty-eight cervical pedicle screws were reviewed in 12 patients; mean age = 65 years, M:F = 2:1, and mean BMI = 27.99. No intra-operative complications related to the cervical pedicle screw placement were reported. Robotic guidance was successful in all 88 screws: eight in C2, 14 in C3, 16 in each of C4 and C5, 19 in C6, and 15 at C7. There were 14 pedicle screw breaches (15.9%); all were medial, less than 1 mm, and with no clinical consequences. In the axial plane, the screws deviated from the preoperative plan by 1.32 ± 1.17 mm and in the sagittal plane by 1.27 ± 1.00 mm. In the trajectory view, the overall deviation was 2.20 ± 1.17 mm. Although differences were observed in screw deviation from the pre-op plan between the right and left sides, they were not statistically significant (p > 0.05). CONCLUSION: This study indicates that robotic-guided cervical pedicle screw placement is feasible and safe. The medial breaches did not result in any clinical consequences.

Spine Patient Satisfaction With Telemedicine During the COVID-19 Pandemic: A Cross-Sectional Study.

STUDY DESIGN: Original research, cross-sectional study. OBJECTIVES: Evaluate patient satisfaction with spine care delivered via telemedicine. Identify patient- and visit-based factors associated with increased satisfaction and visit preference. METHODS: Telemedicine visits with a spine surgeon at 2 practices in the United States between March and May 2020 were eligible for inclusion in the study. Patients were sent an electronic survey recording overall satisfaction, technical or clinical issues encountered, and preference for a telemedicine versus an in-person visit. Factors associated with poor satisfaction and preference of telemedicine over an in-person visit were identified using multivariate logistic regression. RESULTS: A total of 772 responses were collected. Overall, 87.7% of patients were satisfied with their telemedicine visit and 45% indicated a preference for a telemedicine visit over an in-person visit if given the option. Patients with technical or clinical issues were significantly less likely to achieve 5 out of 5 satisfaction scores and were significantly more likely to prefer an in-person visit. Patients who live less than 5 miles from their surgeon's office and patients older than 60 years were also significantly more likely to prefer in-person visits. CONCLUSIONS: Spine telemedicine visits during the COVID-19 pandemic were associated with high patient satisfaction. Additionally, 45% of respondents indicated a preference for telemedicine versus an in-patient visit in the future. In light of these findings, telemedicine for spine care may be a preferable option for a subset of patients into the future.

Minimally Invasive Robotic Lumbar Facet Decortication.

Minimally invasive percutaneous pedicle screws (PPS) are placed through muscle sparing paramedian incisions and provide rigid 3 column fixation to promote stability and fusion. Percutaneous pedicle instrumentation is generally performed as adjunctive posterior stabilization after anterior lumbar interbody fusion or lateral lumbar interbody fusion procedures. In these instances, arthrodesis is often achieved through the interbody fusion rather than posterior column fusion. In some cases, the surgeon may choose to perform posterior facet fusion in addition to PPS and anterior interbody. The addition of a minimally invasive facet fusion to PPS and anterior column interbody fusion creates more fusion surface and enables a truly circumferential fusion. While robotic-guided facet decortication has been suggested, there are currently no published techniques. Here, we describe a novel minimally invasive technique to perform percutaneous robotic facet decortication in conjunction with PPS following anterior lumbar interbody fusion or lateral lumbar interbody fusion.

Seatbelts Save Lives, and Spines, in Motor Vehicle Accidents: A Review of the National Trauma Data Bank in the Pediatric Population.

STUDY DESIGN: Database study. OBJECTIVE: The purpose of this study was to use a large, nationwide database to determine prevalence of pediatric spine fractures in the United States, associated injuries, mechanisms of injury (MOI), use of safety devices, and mortality rates. SUMMARY OF BACKGROUND DATA: Spinal fractures account for 1% to 2% of pediatric injuries. However, they are associated with significant comorbidities and complications. Motor vehicle accidents (MVAs) are most responsible for increased incidence observed. METHODS: Retrospective review of National Trauma Data Bank between 2009 and 2014 (analysis in 2019) for all vertebral fractures in patients under 18 years of age. Subanalysis included those in MVAs where protective device use data were available. Patient demographics, MOI, geographical and anatomical region of injury, concomitant musculoskeletal/organ injury, protective device usage, hospital length of stay, surgical procedures, and mortality were all analyzed. RESULTS: A total of 34,563 patients with 45,430 fractured vertebrae included. Median age was 15 years. Most fractures (63.1%) occurred in patients aged 15 to 17 years, most frequent MOI was MVA (66.8%), and most common geographic location was the South (38%). Males sustained more spine fractures than females, overall (58.4% vs. 41.6%; P < 0.001) and in MVAs (54.4% vs. 45.6%; P < 0.001). Those in MVAs wearing seatbelts had lower odds of cranial (29.6% vs. 70.4%; odds ratio [OR] = 0.85, 95% confidence interval [CI]: 0.82-0.89; P < 0.001) and thoracic (30.1% vs. 69.9%; OR = 0.88, 95% CI: 0.84-0.91; P < 0.001) organ injury, multivertebral (30% vs. 70%; OR = 0.78, 95% CI: 0.73-0.83; P < 0.001) and concomitant nonvertebral fractures (30.9% vs. 69.1%; OR = 0.89, 95% CI:0.73-0.83; P < 0.001), and 21% lower odds of mortality (29.3% vs. 70.7%; OR = 0.79, 95% CI: 0.66-0.94; P = 0.009). Over 70% of drivers were not restrained during MVA, with majority of seatbelt violations incurred by males, ages 15 to 17, in the South. CONCLUSION: Over 60% of pediatric spinal fractures occur in children aged 15 to 17 years, coinciding with the beginning of legal driving. MVA is the most common cause and has significant association with morbidity/mortality. Nearly two- thirds pediatric spinal fractures sustained in MVAs occurred without seatbelts. Absence of seatbelts associated with >20% greater odds of mortality. Ensuring new drivers wear protective devices can greatly reduce morbidity/ mortality associated with MVA.Level of Evidence: 3.

Risk factors for reoperation after lumbar total disc replacement at short-, mid-, and long-term follow-up.

BACKGROUND CONTEXT: The reoperation rate following TDR (Total Disc replacement) has been established at short- and mid-term time points through the Food and Drug Administration Investigational Device Exemption (FDA IDE) trials. However, these trials include highly selected centers and surgeons with strict governance of indications. The utilization of TDR throughout the community needs further analysis. PURPOSE: To identify the risk factors for lumbar spine reoperation in patients undergoing lumbar total disc replacement (TDR) at short-, mid-, and long-term follow-up. STUDY DESIGN/SETTING: This study is a multi-center retrospective cohort study utilizing the New York Statewide Planning and Research Cooperative System database. PATIENT SAMPLE: We identified 1,368 patients who underwent an elective primary lumbar TDR in New York State between January 1, 2005 and September 30, 2013. OUTCOME MEASURES: The primary functional outcome of interest was lumbar reoperation, specifically the evaluation of independent risk factors for lumbar reoperation at a minimum of 2 years, with sub-analyses performed at 5 and ten years. METHODS: International Classification of Diseases, Ninth revision codes were utilized to identify patients undergoing a primary lumbar TDR. We excluded patients with primary/revision lumbar fusion procedures and revision disc replacement procedures. Hospital academic status was determined by the Accreditation Council for Graduate Medical Education. Unique encrypted patient identifiers allowed for longitudinal follow-up for reoperation. Logistic regression models compared reoperation and no-reoperation cohorts, and were performed on sub-analyses for significant univariate predictors of reoperation. RESULTS: Between January 2005 and September 2013, 1368 patients underwent a primary lumbar TDR. Reoperation occurred in 8.8% by 2 years, 15.8% by 5 years, and 19.5% by ten years. Diabetics were more likely to have reoperations (7.5% vs 3.8%, p=.013). Teaching hospitals experienced a decreased reoperation rate compared to nonteaching hospitals at 2-year (5.0% vs 10.5%, p=.002), 5-year (10.7% vs 17.9%, p=.002) and 10-year (11.7% vs 21.9%, p=.045) follow-up. Lumbar fusion was the most common reoperation (14.2%). CONCLUSION: We identified an 8.8% reoperation rate after inpatient lumbar TDR at 2-years, 15.8% at 5-years, and 19.5% at 10-years. When stratifying by teaching status, reoperation rates at teaching centers align with those reported in FDA IDE studies. Diabetes was the only patient factor influencing reoperation rate. There is a growing consensus that lumbar TDR is a durable and appropriate surgical option for lumbar degenerative disc disease. Proper indications are crucial to obtaining good outcomes with lumbar TDR.

Effect of Combined Leukocyte-Poor Platelet-Rich Plasma and Hyaluronic Acid on Bone Marrow-Derived Mesenchymal Stem Cell and Chondrocyte Metabolism.

OBJECTIVE: Given the potential applications of combined biologics, the authors sought to evaluate the in vitro effect of combined platelet-rich plasma (PRP) and hyaluronic acid (HA) on cellular metabolism. DESIGN: Bone marrow-derived mesenchymal stem cells (BMSCs) and chondrocytes were obtained from the femurs of Sprague-Dawley rats. An inflammatory model was created by adding 10 ng/mL interleukin-1-beta to culture media. Non-crosslinked high-molecular-weight HA, activated-PRP (aPRP), and unactivated-PRP (uPRP) were tested. Cellular proliferation and gene expression were measured at 1 week. Genes of interest included aggrecan, matrix metalloproteinase (MMP)-9, and MMP-13. RESULTS: Combined uPRP-HA was associated with a significant increase in chondrocyte and BMSC proliferation at numerous preparations. There was a trend of increased chondrocyte aggrecan expression with combined PRP-HA. The greatest and only significant decrease in BMSC MMP-9 expression was observed with combined PRP-HA. While a significant reduction of BMSC MMP-13 expression was seen with PRP and HA-alone, a greater reduction was observed with PRP-HA. MMP-9 chondrocyte expression was significantly reduced in cells treated with PRP-HA. PRP-alone and HA-alone at identical concentrations did not result in a significant reduction. The greatest reduction of MMP-13 chondrocyte expression was observed in chondrocytes plus combined PRP-HA. CONCLUSIONS: We demonstrated a statistically significant increase in BMSC and chondrocyte proliferation and decreased expression of catabolic enzymes with combined PRP-HA. These results demonstrate the additive in vitro effect of combined PRP-HA to stimulate cellular growth, restore components of the articular extracellular matrix, and reduce inflammation.