The importance of preserving disc structure in surgical approaches to lumbar disc herniation

Limited discectomy versus aggressive discectomy by spinal endoscopy with the transforaminal approach for lumbar disc herniation: a retrospective study

OBJECTIVE

To compare the clinical and radiological outcomes of limited discectomy (LD) and aggressive discectomy (AD) performed via spinal endoscopy using the transforaminal approach in patients with lumbar disc herniation(LDH) METHODS: We conducted a retrospective review of patients who underwent percutaneous endoscopic transforaminal discectomy (PETD) at the L4-L5 lumbar spine segments in our department from January 2017 to December 2020. The follow-up period extended to 24 months postoperatively. Patients were categorized into the LD and AD groups based on the extent of intraoperative disc removal. We retrospectively collected and analyzed clinical and radiological data.

RESULTS

The study followed 65 patients, with 36 in the LD group and 29 in the AD group. No statistically significant differences were noted in recurrence rates, the excellent and good Macnab rates, preoperative Disc Height Index (DHI), and preoperative Modic changes between the groups (P >0.05). However, significant differences were observed in operation duration, postoperative DHI and postoperative Modic change (P<0.05). No significant differences in Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) scores were detected between the groups preoperatively, or one and two years postoperatively (P>0.05). Nevertheless, notable differences in VAS and ODI scores were present one month postoperatively (P<0.05).

CONCLUSION

As a conventional surgical method for treating LDH, PETD can achieve satisfactory clinical results in both LD and AD, with no significant variance in recurrence rates. However, AD is associated with longer operation times, and greater postoperative reductions in DHI and greater postoperative Modic changes compared to LD.

Injectable hydrogel induces regeneration of naturally degenerate human intervertebral discs in a loaded organ culture model

Low back pain resulting from disc degeneration is a leading cause of disability worldwide. However, to date few therapies target the cause and fail to repair the intervertebral disc (IVD). This study investigates the ability of an injectable hydrogel (NPgel), to inhibit catabolic protein expression and promote matrix expression in human nucleus pulposus (NP) cells within a tissue explant culture model isolated from degenerate discs. Furthermore, the injection capacity of NPgel into naturally degenerate whole human discs, effects on mechanical function, and resistance to extrusion during loading were investigated. Finally, the induction of potential regenerative effects in a physiologically loaded human organ culture system was investigated following injection of NPgel with or without bone marrow progenitor cells. Injection of NPgel into naturally degenerate human IVDs increased disc height and Young's modulus, and was retained during extrusion testing. Injection into cadaveric discs followed by culture under physiological loading increased MRI signal intensity, restored natural biomechanical properties and showed evidence of increased anabolism and decreased catabolism with tissue integration observed. These results provide essential proof of concept data supporting the use of NPgel as an injectable therapy for disc regeneration. STATEMENT OF SIGNIFICANCE: Low back pain resulting from disc degeneration is a leading cause of disability worldwide. However, to date few therapies target the cause and fail to repair the intervertebral disc. This study investigated the potential regenerative properties of an injectable hydrogel system (NPgel) within human tissue samples. To mimic the human in vivo conditions and the unique IVD niche, a dynamically loaded intact human disc culture system was utilised. NPgel improved the biomechanical properties, increased MRI intensity and decreased degree of degeneration. Furthermore, NPgel induced matrix production and decreased catabolic factors by the native cells of the disc. This manuscript provides evidence for the potential use of NPgel as a regenerative biomaterial for intervertebral disc degeneration.

A Biomimetic Peptide Functions as Specific Extracellular Matrix for Quiescence of Stem Cells against Intervertebral Disc Degeneration

Maintaining quiescence of stem cells is a potential way to decrease cell nutrition demand for restoring the organization. Herein, a biomimetic peptide to maintain quiescence of stem cells through C-X-C motif chemokine ligand 8 (CXCL8)-C-X-C motif chemokine receptor 1 (CXCR1) pathway against intervertebral disc degeneration (IVDD) is developed. First, it is confirmed that quiescence can be induced via inhibiting phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway in nucleus pulposus stem cells (NPSCs). Meanwhile, it is well known that CXCR1, a chemokine receptor, can be targeted by CXCL8, resulting in cell proliferation via activating PI3K/Akt/mTOR pathway. Second, a biomimetic peptide (OAFF) that can bind to CXCR1 and form fibrous networks on NPSCs, mimicking extracellular matrix formation is developed. The multivalent effect and long-term binding to CXCR1 on NPSCs of OAFF fibers offer forcefully competitive inhibition with natural CXCL8, which induces NPSCs quiescence and ultimately overcomes obstacle in intradiscal injection therapy. In rat caudal disc puncture model, OAFF nanofibers still maintain at 5 weeks after operation and inhibit degeneration process of intervertebral disc in terms of histopathology and imageology. In situ fibrillogenesis of biomimetic peptide on NPSCs provides promising stem cells for intradiscal injection therapy against IVDD.

Cre/LoxP Genetic Recombination Sustains Cartilage Anabolic Factor Expression in Hyaluronan Encapsulated MSCs Alleviates Intervertebral Disc Degeneration

(1) Background: Inexplicable low back and neck pain frequently results from spinal disc degeneration with an imbalanced intervertebral disc (IVD) cell homeostasis. We hypothesize that introducing MSC expressing a sustained cartilage-anabolic factor in the IVD may stimulate the mucoid materials secreted from the IVD cells, promote the MSC’s chondrogenesis and maintain the hydration content providing mechanical strength to decelerate the disc degeneration progression; (2) Methods: This study expressed a cartilage-anabolic factor runx1 by a baculoviral vector (BV) transduced MSCs through a Cre/LoxP gene editing and recombination system for sustained recombinant runx1 transcription factor production. The Cre/LoxP BV modified MSCs were encapsulated by hyaluronan hydrogel, due to its’ vital composition in ECM of a healthy disc and transplanted to a punctured coccygeal disc in rats through micro-injection, followed by X-ray radiography and histological analysis at the 4- and 12-weeks post-transplantation; (3) Results: Data reveals the Cre/LoxP BV system-mediated long-termed runx1 gene expression, possessing good biosafety characteristics in the in vitro cell transduction and in vivo MSCs transplantation, and maintained superior hydration content in the disc than that of mock transduced MSCs; (4) Conclusions: This proof-of-concept study fulfills the need of implanting therapeutic cells accompanied with microinjection in the disc, such as a discography and paves a road to manufacture composite hyaluronan, such as peptide modified hyaluronan as an MSC carrier for IVD regeneration in the future study.

Runx1 Messenger RNA Delivered by Polyplex Nanomicelles Alleviate Spinal Disc Hydration Loss in a Rat Disc Degeneration Model

Vertebral disc degenerative disease (DDD) affects millions of people worldwide and is a critical factor leading to low back and neck pain and consequent disability. Currently, no strategy has addressed curing DDD from fundamental aspects, because the pathological mechanism leading to DDD is still controversial. One possible mechanism points to the homeostatic status of extracellular matrix (ECM) anabolism, and catabolism in the disc may play a vital role in the disease’s progression. If the damaged disc receives an abundant amount of cartilage, anabolic factors may stimulate the residual cells in the damaged disc to secrete the ECM and mitigate the degeneration process. To examine this hypothesis, a cartilage anabolic factor, Runx1, was expressed by mRNA through a sophisticated polyamine-based PEG-polyplex nanomicelle delivery system in the damaged disc in a rat model. The mRNA medicine and polyamine carrier have favorable safety characteristics and biocompatibility for regenerative medicine. The endocytosis of mRNA-loaded polyplex nanomicelles in vitro, mRNA delivery efficacy, hydration content, disc shrinkage, and ECM in the disc in vivo were also examined. The data revealed that the mRNA-loaded polyplex nanomicelle was promptly engulfed by cellular late endosome, then spread into the cytosol homogeneously at a rate of less than 20 min post-administration of the mRNA medicine. The mRNA expression persisted for at least 6-days post-injection in vivo. Furthermore, the Runx1 mRNA delivered by polyplex nanomicelles increased hydration content by ≈43% in the punctured disc at 4-weeks post-injection (wpi) compared with naked Runx1 mRNA administration. Meanwhile, the disc space and ECM production were also significantly ameliorated in the polyplex nanomicelle group. This study demonstrated that anabolic factor administration by polyplex nanomicelle-protected mRNA medicine, such as Runx1, plays a key role in alleviating the progress of DDD, which is an imbalance scenario of disc metabolism. This platform could be further developed as a promising strategy applied to regenerative medicine.

Endoscopic Spinal Decompression: A Retrospective Review of Pain Outcomes at an Academic Medical Center

INTRODUCTION

 Spinal stenosis is a chronic, debilitating condition that is expected to affect an increasing number of people as the population ages. Symptomatic spinal stenosis, like other spine pathologies, including disc herniation and degenerative disc disease, traditionally required an open decompressive surgical approach if more conservative approaches failed. An emerging alternative has been developed to address the needs of this population of patients in the form of endoscopic spine surgery (ESS). Advantages of ESS include minimal tissue trauma, decreased risk of damage to the neurovascular structures, minimal epidural fibrosis/scarring, reduced hospital stay, early functional recovery, and improved cosmetic outcomes. The purpose of this study was to review the outcomes of patients undergoing transforaminal endoscopic spinal decompression at an academic pain program.

METHODS

We conducted a retrospective review of electronic medical records with approval from the University of Florida Institutional Review Board (IRB #202001529). Twenty patients underwent successful transforaminal endoscopic lumbar spinal decompression surgery at UF Health Pain Medicine from July 1, 2019, to June 1, 2020. The majority of cases were performed at L4-5 (n = 14), followed by an equal number (n = 3) of cases at L3-4 and L5-S1. Preoperative and postoperative visual analog scale (VAS) pain scores from patients' pain clinic appointments were obtained from the electronic health records system to assess the intervention as a pain relief strategy.

RESULTS

 Patients had an average pain reduction of 82% (SD = 31%), resulting in an average postoperative pain score of 1.8 (SD = 2.8) on a 10-point VAS.

CONCLUSION

 This study highlights the benefits of endoscopic spine surgery for patients, including pain reduction and reduced scarring.

Effectiveness of an Annular Closure Device to Prevent Recurrent Lumbar Disc Herniation: A Secondary Analysis With 5 Years of Follow-up

IMPORTANCE

Patients with large annular defects following lumbar microdiscectomy for disc herniation are at increased risk for symptomatic recurrence and reoperation.

OBJECTIVE

To determine whether a bone-anchored annular closure device in addition to lumbar microdiscectomy resulted in lower reherniation and reoperation rates vs lumbar microdiscectomy alone.

DESIGN, SETTING, AND PARTICIPANTS

This secondary analysis of a multicenter randomized clinical trial reports 5-year follow-up for enrolled patients between December 2010 and October 2014 at 21 clinical sites. Patients in this study had a large annular defect (6-10 mm width) following lumbar microdiscectomy for treatment of lumbar disc herniation. Statistical analysis was performed from November to December 2020.

INTERVENTIONS

Lumbar microdiscectomy with additional bone-anchored annular closure device (device group) or lumbar microdiscectomy only (control group).

MAIN OUTCOMES AND MEASURES

The incidence of symptomatic reherniation, reoperation, and adverse events as well as changes in leg pain, Oswestry Disability Index, and health-related quality of life when comparing the device and control groups over 5 years of follow-up.

RESULTS

Among 554 randomized participants (mean [SD] age: 43 [11] years; 327 [59%] were men), 550 were included in the modified intent-to-treat efficacy population (device group: n = 272; 270 [99%] were White); control group: n = 278; 273 [98%] were White) and 550 were included in the as-treated safety population (device group: n = 267; control group: n = 283). The risk of symptomatic reherniation (18.8% [SE, 2.5%] vs 31.6% [SE, 2.9%]; P < .001) and reoperation (16.0% [SE, 2.3%] vs 22.6% [SE, 2.6%]; P = .03) was lower in the device group. There were 53 reoperations in 40 patients in the device group and 82 reoperations in 58 patients in the control group. Scores for leg pain severity, Oswestry Disability Index, and health-related quality of life significantly improved over 5 years of follow-up with no clinically relevant differences between groups. The frequency of serious adverse events was comparable between the treatment groups. Serious adverse events associated with the device or procedure were less frequent in the device group (12.0% vs 20.5%; difference, -8.5%; 95% CI, -14.6% to -2.3%; P = .008).

CONCLUSIONS AND RELEVANCE

In patients who are at high risk of recurrent herniation following lumbar microdiscectomy owing to a large defect in the annulus fibrosus, this study's findings suggest that annular closure with a bone-anchored implant lowers the risk of symptomatic recurrence and reoperation over 5 years of follow-up.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01283438.

Negative biomechanical effects of large grade nuclectomy in the transforaminal endoscopic discectomy increased the risk of adjacent segment diseases: A finite element study

PURPOSE

The protection of articular processes (AP) in the transforaminal endoscopic discectomy (TED) was proven to optimise post-operative biomechanical environments. Published studies reported a large grade of nuclectomy leading to poor prognosis, but the underlying biomechanical mechanism was unclearly illustrated. This study aimed to investigate the changes of biomechanical environments after an in-out TED with intact AP and a large grade of nuclectomy and an out-in TED with limited foraminoplasty and a smaller grade of nuclectomy.

METHODS

A previously constructed and validated lumbo-sacral model was used in this study, and in-out TED with intact AP and out-in TED with limited foraminoplasty, a smaller grade of nuclectomy was simulated. Biomechanical changes in the L5-S1 segment related to the degeneration acceleration were computed under different directional loading conditions.

RESULTS

Post-operative biomechanical changes after the out-in TED with limited foraminoplasty were slight, except for the facet contact pressure under the extension position. By contrast, significant biomechanical deterioration, both in the adjacent disc and zygapophyseal joints, is observed under extension in the model after the in-out TED with large nuclectomy.

CONCLUSION

A large grade of nuclectomy is regarded as an independent risk factor of adjacent segment disease in the caudal functional spinal unit after the in-out TED.

TELD with limited foraminoplasty has potential biomechanical advantages over TELD with large annuloplasty: an in-silico study

Background

Facetectomy, an important procedure in the in–out and out–in techniques of transforaminal endoscopic lumbar discectomy (TELD), is related to the deterioration of the postoperative biomechanical environment and poor prognosis. Facetectomy may be avoided in TELD with large annuloplasty, but iatrogenic injury of the annulus and a high grade of nucleotomy have been reported as risk factors influencing poor prognosis. These risk factors may be alleviated in TELD with limited foraminoplasty, and the grade of facetectomy in this surgery can be reduced by using an endoscopic dynamic drill.

Methods

An intact lumbo-sacral finite element (FE) model and the corresponding model with adjacent segment degeneration were constructed and validated to evaluate the risk of biomechanical deterioration and related postoperative complications of TELD with large annuloplasty and TELD with limited foraminoplasty. Changes in various biomechanical indicators were then computed to evaluate the risk of postoperative complications in the surgical segment.

Results

Compared with the intact FE models, the model of TELD with limited foraminoplasty demonstrated slight biomechanical deterioration, whereas the model of TELD with large annuloplasty revealed obvious biomechanical deterioration. Degenerative changes in adjacent segments magnified, rather than altered, the overall trends of biomechanical change.

Conclusions

TELD with limited foraminoplasty presents potential biomechanical advantages over TELD with large annuloplasty. Iatrogenic injury of the annulus and a high grade of nucleotomy are risk factors for postoperative biomechanical deterioration and complications of the surgical segment.

VAST Clinical Trial: Safely Supplementing Tissue Lost to Degenerative Disc Disease

Background

The function of the intervertebral disc is structural. Loss of tissue alters biomechanics, leads to subsequent disc degeneration, and is attributable to discogenic pain. A viable structural allograft was delivered into degenerate discs to determine whether intervention could safely stabilize anatomy, reduce pain, and improve function.

Methods

Following institutional review board approval and patient consent, subjects were randomized to receive allograft or saline at either 1 or 2 levels or continue nonsurgical management (NSM). Data were collected at baseline, 3, 6, and 12 months. Back pain with a visual analog scale (VAS) and disability by the Oswestry Disability Index (ODI) were assessed, as were adverse events. This trial is registered on http://www.clinicaltrials.gov (NCT03709901).

Results

At 6 and 12 months, the VAS improved from 54.81, 55.25, and 62.255 in the allograft, saline, and NSM subjects, respectively, to 16.0 and 41.0 in the allograft and saline groups at 6 months, and 12.27 and 19.67, respectively, at 12 months. All subjects in the NSM cohort crossed over to allograft treatment. At 6 and 12 months, ODI improved from 53.73, 49.25, and 55.75 in the allograft, saline, and NSM subjects, respectively, to 18.47 and 28.75 in the allograft and saline groups 1 and 2 at 6 months, and 15.67 and 9.33, respectively, at 12 months. At 3 months the ODI of the NSM group was 62.75 and subjects reached 19.0 and 11.0 at 6 and 12 months, respectively. Adverse events were transient and resolved in all cohorts.

Conclusions

This study is supported by data demonstrating that improved pain and function at 12 months can be attained with a supplemental viable disc matrix. Subjects receiving the VIA Disc Matrix achieved improvements that were durable at 12 months.

Level of Evidence

1.

Clinical Relevance

Initial assessments indicate that a 1-level or 2-level treatment offers a reliable intervention that is safe and beneficial.

Radiographic measurements of cervical alignment, fusion and subsidence after ACDF surgery and their impact on clinical outcome

BACKGROUND

Some recent studies indicate correlations between cervical alignment and clinical outcome after anterior cervical discectomy and fusion (ACDF) surgery. However, there still are no established criteria for the interpretation of alignment, fusion and subsidence in relation to clinical outcome.

METHODS

A retrospective analysis of 208 radiographs of patients following ACDF with stand-alone PEEK cage implantation was performed. The measurements were obtained on plain radiographs in lateral and anteroposterior projections as well as flexion/extension radiographs. Cervical alignment was measured using the Gore, Laing and Cobb methods; fusion was evaluated by an assortment of radiographic hallmarks: the presence of bridging bone, the Cobb angle and the distances between the tips and bases of the spinous processes of the operated segments, respectively. For assessment of subsidence, we used the Mochida method in addition to ventral and dorsal segmental height reduction. Correlation analysis between the different radiological characteristics and clinical outcome at a minimum follow-up of 12 months was conducted.

RESULTS

Two hundred and eight patients were evaluated for alignment, fusion and subsidence. Cervical alignment using the Gore and Cobb methods correlated among each other, but failed to exhibit significant correlation with clinical outcome. Interpretation of fusion rates varied greatly (43.9 to 89.4%) depending on the criteria used. Pearson coefficients between radiographic presence of pseudarthrosis and the measurements of the spinous process distances (0.595; p < 0.001), the Cobb angles (0.187; p = 0.007) and the presence of bridging bone (0.224; p < 0.001) each exhibited statistical significance. None of the methods employed significantly correlated with clinical outcome. Regarding subsidence, we found rates of 62%, 48% and 27% using the Mochida, ventral and dorsal segmental height reduction assessment methods, respectively. Pearson correlations between pairs of Mochida/ventral (r = 0.39; p = 0.66) and Mochida/dorsal (r = 0.007; p = 0.921) height reduction assessment methods were weak and no significant correlation between subsidence rates and clinical outcome was shown.

CONCLUSION

All measured parameters varied depending in the measurement method used. This was most pronounced for fusion. There was a moderate positive correlation between neck pain and subsidence as measured by the Mochida method.

Lumbar disc reherniation prevention with a bone-anchored annular closure device: 1-year results of a randomized trial

BACKGROUND

The risk of recurrent herniation after lumbar discectomy is highest during the first postoperative year. The purpose of this study was to determine whether implantation of a bone-anchored annular closure device (ACD) following limited lumbar discectomy reduced the risk of recurrent herniation and complications during the first year of follow-up compared to limited lumbar discectomy alone (Controls) and whether this risk was influenced by patient characteristics.

METHODS

In this randomized multicenter trial, patients with symptomatic lumbar disc herniation and with a large annular defect following limited lumbar discectomy were randomized to bone-anchored ACD or Control groups. The risks of symptomatic reherniation, reoperation, and device- or procedure-related serious adverse events were reported over 1 year of follow-up.

RESULTS

Among 554 patients (ACD 276; Control 278), 94% returned for 1-year follow-up. Bone-anchored ACD resulted in lower risks of symptomatic reherniation (8.4% vs. 17.3%, P = .002) and reoperation (6.7% vs. 12.9%, P = .015) versus Controls. Device- or procedure-related serious adverse events through 1 year were reported in 7.1% of ACD patients and 13.9% of Controls (P = .009). No baseline patient characteristic significantly influenced these risks.

CONCLUSIONS

Among patients with large annular defects following limited lumbar discectomy, additional implantation with a bone-anchored ACD lowered the risk of symptomatic reherniation and reoperation over 1 year follow-up. Device- or procedure-related serious adverse events occurred less frequently in the ACD group. These conclusions were not influenced by patient characteristics. ClinicalTrials.gov (NCT01283438).

Closing the Treatment Gap for Lumbar Disc Herniation Patients with Large Annular Defects: A Systematic Review of Techniques and Outcomes in this High-risk Population

Lumbar disc herniation (LDH) is one of the most common spinal pathologies and can be associated with debilitating pain and neurological dysfunction. Discectomy is the primary surgical intervention for LDH and is typically successful. Yet, some patients experience recurrent LDH (RLDH) after discectomy, which is associated with worse clinical outcomes and greater socioeconomic burden. Large defects in the annulus fibrosis are a significant risk factor for RLDH and present a critical treatment challenge. It is essential to identify reliable and cost-effective treatments for this at-risk population. A systematic review of the PubMed and Embase databases was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify studies describing the treatment of LDH patients with large annular defects. The incidence of large annular defects, measurement technique, RLDH rate, and reoperation rate were compiled and stratified by surgical technique. The risk of bias was scored for each study and for the identification of RLDH and reoperation. Study heterogeneity and pooled estimates were calculated from the included articles. Fifteen unique studies describing 2,768 subjects were included. The pooled incidence of patients with a large annular defect was 44%. The pooled incidence of RLDH and reoperation following conventional limited discectomy in this population was 10.6% and 6.0%, respectively. A more aggressive technique, subtotal discectomy, tended to have lower rates of RLDH (5.8%) and reoperation (3.8%). However, patients treated with subtotal discectomy reported greater back and leg pain associated with disc degeneration. The quality of evidence was low for subtotal discectomy as an alternative to limited discectomy. Each report had a high risk of bias and treatments were never randomized. A recent randomized controlled trial with 550 subjects examined an annular closure device (ACD) and observed significant reductions in RLDH and reoperation rates (>50% reduction). Based on the available evidence, current discectomy techniques are inadequate for patients with large annular defects, leaving a treatment gap for this high-risk population. Currently, the strongest evidence indicates that augmenting limited discectomy with an ACD can reduce RLDH and revision rates in patients with large annular defects, with a low risk of device complications.

Recurrent lumbar disc herniation: Is there a correlation with the surgical technique? A multivariate analysis

Purpose

The recurrence of a lumbar disc herniation (LDH) is a common cause of poor outcome following lumbar discectomy. The aim of this study was to assess a potential relationship between the incidence of recurrent LDH and the surgical technique used. Furthermore, we tried to define the best surgical technique for the treatment of recurrent LDH to limit subsequent recurrences.

Materials and Methods

A retrospective study was conducted on 979 consecutive patients treated for LDH. A multivariate analysis tried to identify a possible correlation between (1) the surgical technique used to treat the primary LDH and its recurrence; (2) technique used to treat the recurrence of LDH and the second recurrence; and (3) incidence of recurrence and clinical outcome. Data were analyzed with the Pearson's Chi-square test for its significance.

Results

In 582 cases (59.4%), a discectomy was performed, while in 381 (40.6%), a herniectomy was undertaken. In 16 cases, a procedure marked as "other" was performed. Among all patients, 110 (11.2%) had a recurrence. Recurrent LDH was observed in 55 patients following discectomy (9.45%), in 45 following herniectomy (11.8%), and in 10 (62.5%) following other surgery. Our data showed that 90.5% of discectomies and 88.2% of the herniectomies had a good clinical outcome, whereas other surgeries presented a recurrence rate of 62.5% (Pearson's χ²< 0.001). No statistical differences were observed between discectomy or herniectomy, for the treatment of the recurrence, and the incidence for the second recurrences (P > 0.05). A significant statistical correlation emerged between the use of other techniques and the incidence for the second recurrences (P < 0.05).

Conclusions

The recurrence of an LDH is one of the most feared complications following surgery. Although the standard discectomy has been considered more protective toward the recurrence compared to herniectomy, our data suggest that there is no significant correlation between the surgical technique and the risk of LDH recurrence.

Treatment of Intervertebral Disk Disease by the Administration of mRNA Encoding a Cartilage-Anabolic Transcription Factor

Intervertebral disk (IVD) degeneration is often associated with severity of lower back pain. IVD core is an avascular, highly hydrated tissue composed of type II collagen, glycosaminoglycans, and proteoglycans. The disk degeneration is not only a destruction of IVD structure but also is related to a disorder of the turnover of the disk matrix, leading the jelly-like IVD core to be replaced by fibrous components. Here we present a disease-modifying strategy for IVD degenerative diseases by direct regulation of the cells in the IVD using mRNA medicine, to alter the misbalanced homeostasis during disk degeneration. When mRNA encoding a cartilage-anabolic transcription factor, runt-related transcription factor-1, was administered to a rat model of coccygeal disk degeneration using a polyplex nanomicelle composed of polyethylene glycol-polyamino acid block copolymers and mRNA, the disk height was maintained to a significantly higher extent (≈81%) compared to saline control (69%), with prevention of fibrosis in the disk tissue. In addition, the use of nanomicelles effectively prevented inflammation, which was observed by injection of naked mRNA into the disk. This proof-of-concept study revealed that mRNA medicine has a potential for treating IVD degenerative diseases by introducing a cartilage-anabolic factor into the host cells, proposing a new therapeutic strategy using mRNA medicine.

Condoliase for the Treatment of Lumbar Disc Herniation: A Randomized Controlled Trial

STUDY DESIGN

A randomized, double-blind, placebo-controlled, multicenter phase III clinical trial.

OBJECTIVE

To evaluate the efficacy and safety of chemonucleolysis with condoliase in patients with lumbar disc herniation (LDH).

SUMMARY OF BACKGROUND DATA

Condoliase is a pure mucopolysaccharidase derived from a bacterium, Proteus vulgaris that has high substrate specificity for chondroitin sulfate and hyaluronic acid in the nucleus pulposus of the intervertebral disc.

METHODS

In this study, patients aged 20 to 70 years with unilateral leg pain, positive straight leg raise test, and a contained LDH were recruited in Japan. Patients were treated with a single injection of condoliase (1.25 U) or placebo and were followed for 1 year after administration. The primary endpoint was change in worst leg pain from baseline to week 13. The secondary endpoints included responder rate, and the changes from baseline up to week 52 in the worst leg pain, worst back pain, Oswestry Disability Index, 36-Item Short-Form Health Survey, neurologic examinations, and imaging parameters.

RESULTS

A total of 82 and 81 patients received an injection of condoliase and placebo, respectively. The average changes in worst leg pain from baseline to week 13 (primary endpoint) were -49.5 mm in the condoliase group and -34.3 mm in the placebo group, and the difference of -15.2 mm was significant (95% confidence interval, -24.2 to -6.2; P = 0.001). Significant improvements were observed in the condoliase groups, compared with the placebo group, in most secondary endpoints at 1 year after administration. In the condoliase group, back pain, Modic type 1 change, and decrease in disc height were frequently reported, without any clinically relevant consequences.

CONCLUSION

Condoliase significantly improved symptoms in patients with LDH and was well tolerated. Condoliase is a novel and potent chemonucleolytic drug for the treatment of LDH.

LEVEL OF EVIDENCE

1.

A multicenter, randomized, double-blind, dose-finding study of condoliase in patients with lumbar disc herniation

OBJECTIVE

Chemonucleolysis with condoliase has the potential to be a new, less invasive therapeutic option for patients with lumbar disc herniation (LDH). The aim of the present study was to determine the most suitable therapeutic dose of condoliase.

METHODS

Patients between 20 and 70 years of age with unilateral leg pain, positive findings on the straight leg raise test, and LDH were recruited. All eligible patients were randomly assigned to receive condoliase (1.25, 2.5, or 5 U) or placebo. The primary end point was a change in the worst leg pain from preadministration (baseline) to week 13. The secondary end points were changes from baseline in the following items: worst back pain, Oswestry Disability Index (ODI), SF-36, and neurological examination. For pharmacokinetic and pharmacodynamic analyses, plasma condoliase concentrations and serum keratan sulfate concentrations were measured. The safety end points were adverse events (AEs) and radiographic and MRI parameters. Data on leg pain, back pain, abnormal neurological findings, and imaging parameters were collected until week 52.

RESULTS

A total of 194 patients received an injection of condoliase or placebo. The mean change in worst leg pain from baseline to week 13 was −31.7 mm (placebo), −46.7 mm (1.25 U), −41.1 mm (2.5 U), and −47.6 mm (5 U). The differences were significant at week 13 in the 1.25-U group (−14.9 mm; 95% CI −28.4 to −1.4 mm; p = 0.03) and 5-U group (−15.9 mm; 95% CI −29.0 to −2.7 mm; p = 0.01) compared with the placebo group. The dose-response improvement in the worst leg pain at week 13 was not significant (p = 0.14). The decrease in the worst leg pain in all 3 condoliase groups was observed from week 1 through week 52. Regarding the other end points, the worst back pain and results of the straight leg raise test, ODI, and SF-36 showed a tendency for sustained improvement in each of the condoliase groups until week 52. In all patients at all time points, plasma condoliase concentrations were below the detectable limit (< 100 μU/ml). Serum keratan sulfate concentrations significantly increased from baseline to 6 hours and 6 weeks after administration in all 3 condoliase groups. No patient died or developed anaphylaxis or neurological sequelae. Five serious AEs occurred in 5 patients (3 patients in the condoliase groups and 2 patients in the placebo group), resolved, and were considered unrelated to the investigational drug. Severe AEs occurred in 10 patients in the condoliase groups and resolved or improved. In the condoliase groups, back pain was the most frequent AE. Modic type 1 change and decrease in disc height were frequent imaging findings. Dose-response relationships were observed for the incidence of adverse drug reactions and decrease in disc height.

CONCLUSIONS

Condoliase significantly improved clinical symptoms in patients with LDH and was well tolerated. While all 3 doses had similar efficacy, the incidence of adverse drug reactions and decrease in disc height were dose dependent, thereby suggesting that 1.25 U would be the recommended clinical dose of condoliase.

Clinical trial registration no.: NCT00634946 (clinicaltrials.gov)

First Results of a New Vacuum Plasma Sprayed (VPS) Titanium-Coated Carbon/PEEK Composite Cage for Lumbar Interbody Fusion

The aim of this study was to assess the performance of a new vacuum plasma sprayed (VPS) titanium-coated carbon/polyetheretherketone (PEEK) cage under first use clinical conditions. Forty-two patients who underwent a one or two segment transforaminal lumbar interbody fusion (TLIF) procedure with a new Ca/PEEK composite cage between 2012 and 2016 were retrospectively identified by an electronic patient chart review. Fusion rates (using X-ray), patient’s satisfaction, and complications were followed up for two years. A total of 90.4% of the patients were pain-free and satisfied after a follow up (FU) period of 29.1 ± 9 (range 24–39) months. A mean increase of 3° in segmental lordosis in the early period (p = 0.002) returned to preoperative levels at final follow-ups. According to the Bridwell classification, the mean 24-month G1 fusion rate was calculated as 93.6% and the G2 as 6.4%. No radiolucency around the cage (G3) or clear pseudarthrosis could be seen (G4). In conclusion, biological properties of the inert, hydrophobic surface, which is the main disadvantage of PEEK, can be improved with VPS titanium coating, so that the carbon/PEEK composite cage, which has great advantages in respect of biomechanical properties, can be used safely in TLIF surgery. High fusion rates, good clinical outcome, and low implant-related complication rates without the need to use rhBMP or additional iliac bone graft can be achieved.

Treatment of lumbar degenerative disc disease-associated radicular pain with culture-expanded autologous mesenchymal stem cells: a pilot study on safety and efficacy

Background

Degenerative disc disease (DDD) is a common cause of lower back pain with radicular symptoms and has a significant socioeconomic impact given the associated disability. Limited effective conservative therapeutic options result in many turning to surgical alternatives for management, which vary in the rate of success and also carry an increased risk of morbidity and mortality associated with the procedures. Several animal based studies and a few human pilot studies have demonstrated safety and suggest efficacy in the treatment of DDD with mesenchymal stem cells (MSCs). The use of bone marrow-derived MSCs for the treatment of DDD is promising and in the present study we report on the safety and efficacy findings from a registry based proof of concept study using a percutaneous intradiscal injection of cultured MSCs for the management of DDD with associated radicular symptoms.

Methods

Thirty-three patients with lower back pain and disc degeneration with a posterior disc bulge diagnosed on magnetic resonance imaging (MRI) met the inclusion criteria and were treated with culture-expanded, autologous, bone marrow-derived MSCs. Prospective registry data was obtained at multiple time intervals up to 6 years post-treatment. Collected outcomes included numeric pain score (NPS), a modified single assessment numeric evaluation (SANE) rating, functional rating index (FRI), measurement of the intervertebral disc posterior dimension, and adverse events.

Results

Three patients reported pain related to procedure that resolved. There were no serious adverse events (i.e. death, infection, or tumor) associated with the procedure. NPS change scores relative to baseline were significant at 3, 36, 48, 60, and 72 months post-treatment. The average modified SANE ratings showed a mean improvement of 60% at 3 years post-treatment. FRI post-treatment change score averages exceeded the minimal clinically important difference at all time points except 12 months. Twenty of the patients treated underwent post-treatment MRI and 85% had a reduction in disc bulge size, with an average reduction size of 23% post-treatment.

Conclusions

Patients treated with autologous cultured MSCs for lower back pain with radicular symptoms in the setting of DDD reported minor adverse events and significant improvements in pain, function, and overall subjective improvement through 6 years of follow-up.

NCT03011398. A Clinical Registry of Orthobiologics Procedures. https://clinicaltrials.gov/ct2/show/NCT03011398?term=orthobiologics&rank=1

Factors associated with lumbar disc hernia recurrence after microdiscectomy

INTRODUCTION

Lumbar disc hernias are a common cause of spinal surgery. Hernia recurrence is a prevalent complication.

OBJECTIVE

To analyse the risk factors associated with hernia recurrence in patients undergoing surgery in our institution.

MATERIALS AND METHODS

Lumbar microdiscectomies between 2010 and 2014 were analysed, patients with previous surgeries, extraforaminales and foraminal hernias were excluded. Patients with recurrent hernia were the case group and those who showed no recurrence were the control group.

RESULTS

177 patients with lumbar microdiscectomy, of whom 30 experienced recurrence (16%), and of these 27 were reoperated. Among the risk factors associated with recurrence, we observed a higher rate of disc height, higher percentage of spinal canal occupied by the hernia and presence of degenerative facet joint changes; we observed no differences in sex, body mass index or age.

DISCUSSION

Previous studies show increased disc height and young patients as possible factors associated with recurrence.

CONCLUSION

In our series we found that the higher rate of disc height, the percentage of spinal canal occupied by the hernia and degenerative facet joint changes were associated with hernia recurrence.

Percutaneous endoscopic lumbar discectomy: minimally invasive technique for multiple episodes of lumbar disc herniation

Backgrounds

Although open lumbar discectomy is a gold standard surgical technique for lumbar disc herniation (LDH), surgery-induced tissue injury may actually become a source of postsurgical pain. Percutaneous endoscopic lumbar discectomy (PELD) is introduced as a minimal invasive spinal technique for LDH. The PELD has gained popularity and shown successful results. The authors report the clinical usefulness of the PELD technique in two patients with the serial multilevel LDHs.

Case presentations

A 32-year-old man suffered from radicular pain at the L5 dermatome due to the down migrated soft LDH at the L4–5 level. The PELD was performed to remove the ruptured fragments, yielding a complete decompression of the L5 nerve root. Four years later, he visited the clinic because of right leg radiating pain along the S1 dermatome. An MRI scan revealed the LDH at the L5-S1 level. The PELD with foraminoplasty was also performed successfully at the L5-S1 level. Two months after the second PELD, he visited the clinic again because of severe pain along the left L4 dermatome; consequently, the PELD was also performed at the L3–4 level without any complications. A 34-year-old man presented with radiating pain in the back and both legs at the L5 dermatome. The MR images show a disc extrusion at the L4–5. The patient underwent the PELD at the L4–5 via the left approach. After the PELD, the back and leg pain both improved. One year later, the patient suffered from severe pain in the back and the left anterior thigh. The MR images show a left paramedian LDH at the L2–3. After the PELD was performed at the L2–3, the pain was relieved. The final MR images show no signs of any aggravated degeneration of the intervertebral discs or the facet joints at all of the treated levels.

Conclusion

When multiple episodes of LDH occur in a patient’s life span, PELD could be considered as an alternative good technique to treat LDH in each step by preserving normal anatomic structures.

Surgical Outcome of Percutaneous Endoscopic Interlaminar Lumbar Discectomy for Highly Migrated Disk Herniation

STUDY DESIGN

Technical report.

OBJECTIVE

To present a detailed surgical technique for percutaneous endoscopic interlaminar discectomy (PEID) for highly migrated disk herniation.

SUMMARY OF BACKGROUND DATA

Percutaneous lumbar endoscopic discectomy for highly migrated disk herniation is still challenging even for an experienced surgeon. Because of the risk of failure and technical difficulty, open discectomy is recommended for a high-grade migration. However, past reports focused on the transforaminal approach (percutaneous endoscopic transforaminal discectomy) and may give a biased impression. We may overlook the merit of PEID. The surgical procedure for PEID is similar to a traditional open discectomy and the range of approach could be widened by the inclined introduction and pivoting motion of an endoscope.

METHODS

Eighteen consecutive patients (M:F=12:6; age, 56±15 y) with highly migrated disk herniation were enrolled for the present study. The disk material was migrated superiorly in 7 patients (L4-5, 4; L5-S1, 2; L2-3, 1) and inferiorly in 11 patients (L4-5, 6; L3-4, 4; L5-S1, 1). PEID was applied in 17 patients and PETD was performed for L2-3 disk herniation. The follow-up period was 16±12 months. The outcome was graded using the MacNab criteria.

RESULTS

Complete removal of the disk material was confirmed with magnetic resonance imaging in 16 patients (success rate 89%). Revision operation was necessary in 2 patients with inferior migration from L4-5. The residual disk was removed through the L5-S1 laminar window 2 days after surgery with excellent outcome at the last follow-up. The outcome at the last follow-up was excellent in 12 patients, good in 3, fair in 2, and poor in 1. Dural tear was suspected in 1 patient without any further problems and there was no recurrence during follow-up.

CONCLUSIONS

PEID may be applied comfortably even for less-experienced surgeons because of the familiar anatomy with open surgery.

The Effect and Feasibility Study of Transforaminal Percutaneous Endoscopic Lumbar Discectomy Via Superior Border of Inferior Pedicle Approach for Down-Migrated Intracanal Disc Herniations

Transforaminal percutaneous endoscopic lumbar discectomy (PELD) is gradually regarded as an effective alternative to posterior open surgery. However, migrated herniations bring a great technical challenge even for experienced surgeons due to the absence of the appropriate approaching guideline. We aimed to describe a safe and effective approaching technique for the removal of down-migrations on the basis of the clinical outcomes and complications compared with the conventional approaching method.A total of 45 patients recommended to single-level PELD with foraminoplasty were randomly divided into 2 groups, group A received foraminoplasty via upper border of inferior pedicle, group B was approached through the common transforaminal route. The clinical outcomes were evaluated by Visual Analog Scale (VAS) for leg pain and Oswestry Disability Index (ODI) scores. Then participants were classified into 2 types of migrations (high-grade and low-grade) based on the extent of migration presented on preoperative magnetic resonance imaging (MRI). The various comparisons between the 2 surgical techniques were analyzed.The postoperative VAS and ODI scores significantly decreased in both of the 2 groups after surgery (P < 0.001). The follow-up continued 1 year. With increasing length of follow-up, the disparities in clinical outcomes between the 2 groups were gradually narrowing and there was no significant difference at the end of follow-up (P = 0.32; P = 0.46). There were no differences in the operation time and duration of hospital stay (P = 0.36; P = 0.08). The highly migration group in group B showed a significant longer operation time (P = 0.02), but the extent of migration did not have a significant influence on the operation time in group A with the modified approach (P = 0.19). There were no apparent approach-related complications in group A during the procedure and follow-up period.Foraminoplastic-PELD via upper border of inferior pedicle can serve as a safe and effective minimally invasive technique for removal of down-migrated herniations. Furthermore, it is essential to identify the radiologic characteristics so as to choose the most appropriate approaching technique.

Evaluation of an In Situ Gelable and Injectable Hydrogel Treatment to Preserve Human Disc Mechanical Function Undergoing Physiologic Cyclic Loading Followed by Hydrated Recovery

Despite the prevalence of disc degeneration and its contributions to low back problems, many current treatments are palliative only and ultimately fail. To address this, nucleus pulposus replacements are under development. Previous work on an injectable hydrogel nucleus pulposus replacement composed of n-carboxyethyl chitosan, oxidized dextran, and teleostean has shown that it has properties similar to native nucleus pulposus, can restore compressive range of motion in ovine discs, is biocompatible, and promotes cell proliferation. The objective of this study was to determine if the hydrogel implant will be contained and if it will restore mechanics in human discs undergoing physiologic cyclic compressive loading. Fourteen human lumbar spine segments were tested using physiologic cyclic compressive loading while intact, following nucleotomy, and again following treatment of injecting either phosphate buffered saline (PBS) (sham, n = 7) or hydrogel (implant, n = 7). In each compressive test, mechanical parameters were measured immediately before and after 10,000 cycles of compressive loading and following a period of hydrated recovery. The hydrogel implant was not ejected from the disc during 10,000 cycles of physiological compression testing and appeared undamaged when discs were bisected following all mechanical tests. For sham samples, creep during cyclic loading increased (+15%) from creep during nucleotomy testing, while for implant samples creep strain decreased (-3%) toward normal. There was no difference in compressive modulus or compressive strains between implant and sham samples. These findings demonstrate that the implant interdigitates with the nucleus pulposus, preventing its expulsion during 10,000 cycles of compressive loading and preserves disc creep within human L5-S1 discs. This and previous studies provide a solid foundation for continuing to evaluate the efficacy of the hydrogel implant.

Is sequestrectomy a viable alternative to microdiscectomy? A systematic review of the literature

BACKGROUND

Traditionally, lumbar discectomy involves removal of the free disc fragment followed by aggressive or conservative excision of the intervertebral disc. In selected patients, however, it is possible to remove only the free fragment or sequester without clearing the intervertebral disc space. However, there is some controversy about whether that approach is sufficient to prevent recurrent symptoms and to provide adequate pain relief.

QUESTIONS/PURPOSES

This systematic review was designed to pose two questions: (1) Does performing a sequestrectomy only without conventional microdiscectomy lead to an increased reherniation rate; and (2) is there a difference in the patient-reported levels of radicular pain?

METHODS

Systematic MEDLINE and EMBASE searches were carried out to identify all articles published in peer-reviewed journals reporting the outcomes of interest for conventional microdiscectomy versus sequestrectomy for lumbar disc herniation from L2 to the sacrum (Level III evidence and above); hand-searching of bibliographies was also performed. A minimum of Level II evidence was required with a followup rate of greater than 75%. Followup in all studies was from 18 to 86 months. Seven studies met the inclusion criteria for this review. The studies were analyzed for operating time, hospital stay, pre- and postoperative visual analog scale, and reherniation rate.

RESULTS

Patients in both the microdiscectomy and sequestrectomy groups showed comparable improvement of visual analog scale (VAS) score for leg pain. VAS score improvement ranged from 5.6 to 6.5 points in the microdiscectomy groups and 5.5 to 6.6 in the sequestrectomy group. The reherniation rate in the microdiscectomy group ranged from 2.3% to 11.8% and in the sequestrectomy groups from 2% to 12.5%.

CONCLUSIONS

This review of the available literature suggests that, compared with conventional microdiscectomy, microsurgical lumbar sequestrectomy can achieve comparable reherniation rates and reduction in radicular pain when a small breach in the posterior fibrous ring is found intraoperatively.

Minimally invasive percutaneous endoscopic 2 levels adjacent lumbar discectomy through 1 portal skin incision: Preliminary study

Background:

Acute lumbar disc herniation can occur in every lumbar intervertebral disc space and in multiple levels simultaneously. In the cases of 2 levels adjacent lumbar disc herniations of severe unilateral radiculopathic leg pain caused by compression of the nerve roots, respectively, multiple incision or long incision is generally needed for simultaneous removal of disc fragment in 2 levels.

Objectives:

We proposed the minimally invasive one portal skin incision endoscopic discectomy is effective and safe method to treat 2 levels adjacent lumbar disc herniation.

Materials and Methods:

We have experimented total 8 cases of 2 levels adjacent lumbar disc herniation having unilateral radiculopathic pain respectively. All cases are 2 levels adjacent lumbar disc herniation. We have tried a percutaneous endoscopic transforaminal approach through minimal one portal skin incision and remove the two herniated disc materials in the adjacent levels.

Results:

The L2-L3 level was involved in 2 patients, L3-L4 level in 6 patients, while the L4-L5 level was involved in 7 patients, L5-S1 level in 1 patient. The mean follow-up was 18.5 months. The mean visual analogue score (VAS) of the patients prior to surgery was 7.75, and the mean postoperative VAS was 2.375. According to Macnab's criteria, 3 patients had excellent results, 4 patients had good results, 1 patient had fair results, and no patient had a poor result; satisfactory results were obtained in 87.5% of the cases.

Conclusion:

The percutaneous endoscopic transforaminal approach through 1 skin portal incision could be effective surgical method in unilateral adjacent 2 levels lumbar disc herniation.

Comparison of discectomy versus sequestrectomy in lumbar disc herniation: a meta-analysis of comparative studies

Background

Lumbar disc removal is currently the standard treatment for lumbar disc herniation. No consensus has been achieved whether aggressive disc resection with curettage (discectomy) versus conservative removal of the offending disc fragment alone (sequestrectomy) provides better outcomes. This study aims to compare the reherniation rate and clinical outcomes between discectomy and sequestrectomy by literature review and a meta-analysis.

Methods

A systematic search of PubMed, Medline, Embase and the Cochrane Library was performed up to June 1, 2014. Outcomes of interest assessing the two techniques included demographic and clinical baseline characteristics, perioperative variables, complications, recurrent herniation rate and post-operative functional outcomes.

Results

Twelve eligible trials evaluating discectomy vs sequestrectomy were identified including one randomized controlled study, five prospective and six retrospective comparative studies. By contrast to discectomy, sequestrectomy was associated with significantly less operative time (p<0.001), lower visual analogue scale (VAS) for low back pain (p<0.05), less post-operative analgesic usage (p<0.05) and better patients’ satisfaction (p<0.05). Recurrent herniation rate, reoperation rate, intraoperative blood loss, hospitalization duration and VAS for sciatica were without significant difference.

Conclusions

According to our pooled data, sequestrectomy entails equivalent reherniation rate and complications compared with discectomy but maintains a lower incidence of recurrent low back pain and higher satisfactory rate. High-quality prospective randomized controlled trials are needed to firmly assess these two procedures.

Stem cell therapy for intervertebral disc regeneration: obstacles and solutions

Intervertebral disc (IVD) degeneration is frequently associated with low back and neck pain, which accounts for disability worldwide. Despite the known outcomes of the IVD degeneration cascade, the treatment of IVD degeneration is limited in that available conservative and surgical treatments do not reverse the pathology or restore the IVD tissue. Regenerative medicine for IVD degeneration, by injection of IVD cells, chondrocytes or stem cells, has been extensively studied in the past decade in various animal models of induced IVD degeneration, and has progressed to clinical trials in the treatment of various spinal conditions. Despite preliminary results showing positive effects of cell-injection strategies for IVD regeneration, detailed basic research on IVD cells and their niche indicates that transplanted cells are unable to survive and adapt in the avascular niche of the IVD. For this therapeutic strategy to succeed, the indications for its use and the patients who would benefit need to be better defined. To surmount these obstacles, the solution will be identified only by focused research, both in the laboratory and in the clinic.

Lumbar Microdiscectomy: A Clinicoradiological Analysis of Outcome

Background:

The long-term outcome after lumbar microdiscectomy (LMD) may be affected by low back pain (LBP) and segmental instability, the determinants of which remain unclear. We sought to analyze the interaction between clinical, functional, and radiological variables and their impact on patient outcome.

Methods:

All patients who underwent LMD in 2004-2005 were invited to participate in this retrospective cohort study. Patients were re-evaluated clinically and radiologically after a three to five year follow-up.

Results:

Forty-one of 97 eligible patients were enrolled. Twelve patients (29.3%) reported moderate-to-severe sciatica, 12 (29.3%) had moderate LBP, and 13 (31.7%) exhibited clinical evidence of segmental instability. Thirty-eight patients (92.7%) had minimal disability and 3 (7.3%) had moderate disability. Twenty-three patients (56.1%) were fully satisfied, while 18 (43.9%) had only partial satisfaction, having expected a better outcome. Thirty-three patients (80.5%) returned to full-time work. Median disc space collapse (DSC) was 20% (range 5-66%) and L4-L5 was particularly affected. Prevalence of Modic changes increased from 46.3% to 78% with type 2 predominance. Multivariate logistic regression analysis identified the following negative prognostic factors: female sex, young age, lack of regular exercise, and chronic preoperative LBP. There was no correlation between the course of Modic changes, DSC, and patient outcome.

Conclusion:

Although many patients may be symptomatic following LMD, significant disability and dissatisfaction are uncommon. Female sex, young age, lack of exercise, and chronic preoperative LBP may predict a worse outcome. Disc collapse is a universal finding, particularly at L4-L5. Neither DSC nor Modic changes seem to affect patient outcome.

Percutaneous endoscopic intra-annular subligamentous herniotomy for large central disc herniation: a technical case report

STUDY DESIGN

Technical case report.

OBJECTIVE

To describe the novel technique of percutaneous endoscopic herniotomy using a unilateral intra-annular subligamentous approach for the treatment of large centrally herniated discs.

SUMMARY OF BACKGROUND DATA

Open discectomy for large central disc herniations may have poor long-term prognosis due to heavy loss of intervertebral disc tissue, segmental instability, and recurrence of pain.

METHODS

Six consecutive patients who presented with back and leg pain, and/or weakness due to a large central disc herniation were treated using percutaneous endoscopic herniotomy with a unilateral intra-annular subligamentous approach.

RESULTS

The patients experienced relief of symptoms and intervertebral disc spaces were well maintained. The annular defects were noted to be in the process of healing and recovery.

CONCLUSION

Percutaneous endoscopic unilateral intra-annular subligamentous herniotomy was an effective and affordable minimally invasive procedure for patients with large central disc herniations, allowing preservation of nonpathological intradiscal tissue through a concentric outer-layer annular approach.

Increase in facet joint loading after nucleotomy in the human lumbar spine

Low-back pain has been related to degenerative changes after nucleotomy. Although several etiologies for pain after nucleotomy have been proposed, there is evidence of pain arising in the facet joints in general, which may be related to changes in load transfer. This study addresses the effect of nucleotomy on facet joint loading. Nine human lumbar motion segments (age: 40-59 years) were loaded in axial compression and extension-flexion. Reaction forces were compared with soft tissue structures sequentially removed. After nucleotomy the facets supported significantly greater load, almost doubling from a median of 8.6% of the applied external force to 15.8%. Force transmission related to the capsular ligament increased significantly from an intact median of 1.2-5.1% after nucleotomy. No correlation was observed between force increase on the facets and the proportion of disc nucleus removed. Even a small quantity of nucleus removal (range: 0.7-1.7g) increased the forces transmitted over the facet joints, both with and without capsular ligaments. This suggests that the proportion of material removed might not be important clinically with regard to facet joint degeneration and pain.

Recurrence Rate after Herniotomy only versus Discectomy in Lumbar Disc Herniation

Objective

Lumbar disc herniation (LDH) recurrence necessitating reoperation can pose problems following spinal surgery, with an overall reported incidence of approximately (3-13%). The purpose of this study is to identify the rate of recurrent disc herniation, to discuss the radiologic indications for herniotomy and to analyze clinical outcomes compared with conventional discectomy.

Methods

This study is a retrospective case control study. The authors retrospectively reviewed 114 patients who underwent herniotomy & conventional discectomy by a single surgeon for single-level LDH between June 2009 and May 2012. Herniotomy group was 57 patients and conventional discectomy group was 57 patients that were selected from 631 patients using stratified randomization. Evaluation for LDH recurrence included detailed medical chart and radiologic review and telephone interview. Postoperative VAS and the Korean version of ODI were examined one week after surgery. Clinical outcome was investigated according to Odom's criteria from three months to three years.

Results

Of the 114 patients for whom the authors were able to definitively assess symptomatic recurrence status, four patients (7%) experienced LDH recurrence following single-level herniotomy and three patients (5.2%) conventional discectomy. There were no differences in the VAS and Korean version of ODI between herniotomy group and conventional discectomy group. The herniotomy group had better results than the conventional discectomy group in clinical outcome from three months to three years, but the difference was not significant.

Conclusion

There were no significant differences in clinical outcome between herniotomy and conventional discectomy. Recurrence rates following herniotomy for LDH compare favorably with those in patients who have undergone conventional discectomy, lending further support for its effectiveness in treating herniotomy.

The effect of nucleotomy on facet joint loading - a porcine in vitro study

BACKGROUND

Lumbar facet joints have been cited as a possible origin of low-back pain. A relationship between disc height decrease and facet joint degeneration has been reported. Facet joint degeneration may also be triggered by nucleotomy, performed on prolapsed discs, which might change the natural load sharing between the anterior and posterior structures of the spine. In this study load bearing of the facet joints was compared between natural and nucleotomised spinal segments.

METHODS

Nine porcine lumbar motion segments were tested quasi-statically in ±1.5° extension-flexion under 700 N constant compression loading. The kinematics of the spinal segments were recorded as a response to the applied load. These kinematics were subsequently applied to the segments with the ligaments and disc sequentially removed and the reaction forces measured. This was performed in samples with and without nucleotomy. Comparison of the reaction forces allowed a direct comparison between healthy and pathological force transmission over the facet joints. Load sharing was related to the proportion of removed nucleus.

FINDINGS

The proportion of applied compression force supported by the facets increased from a mean of 40.7% (standard deviation, SD 10.0%) to 82.0% (SD 7.2%) after nucleotomy averaged over the entire extension-flexion regime. No correlation was observed between facet loading and the proportion of the nucleus removed.

INTERPRETATION

Increased facet loading after nucleotomy might cause greater cartilage wear, which may be related to facet joint degeneration. The independence of facet loading on the proportion of nucleus removed might be due to a complete pressure loss once the annulus is incised.

A novel approach to the surgical treatment of lumbar disc herniations: indications of simple discectomy and posterior transpedicular dynamic stabilization based on carragee classification

Surgery of lumbar disc herniation is still a problem since Mixter and Barr. Main trouble is dissatisfaction after the operation. Today there is a debate on surgical or conservative treatment despite spending great effort to provide patients with satisfaction. The main problem is segmental instability, and the minimally invasive approach via microscope or endoscope is not necessarily appropriate solution for all cases. Microsurgery or endoscopy would be appropriate for the treatment of Carragee type I and type III herniations. On the other hand in Carragee type II and type IV herniations that are prone to develop recurrent disc herniation and segmental instability, the minimal invasive techniques might be insufficient to achieve satisfactory results. The posterior transpedicular dynamic stabilization method might be a good solution to prevent or diminish the recurrent disc herniation and development of segmental instability. In this study we present our experience in the surgical treatment of disc herniations.

Relationship of surgical accuracy and clinical outcomes in Charitè lumbar disc replacement

OBJECTIVE

To retrospectively assess the clinical and functional outcomes of a group of patients receiving Charitè lumbar disc replacement and to compare those outcomes to the corresponding surgical technical accuracy.

METHODS

A retrospective study of all patients treated over a 3-year period was undertaken. Objective pain scores were quantified from 1 to 10. Short Form 36-Health Survey (SF-36v2) scores were compared to Australian population norms. Surgical placements were radiographically classified. Heterotopic ossification, disc height restoration and angle-defined instability were assessed using established protocols.

RESULTS

Twenty-five patients were identified with three patients lost to follow-up. Average follow-up was 34 months. Ideal surgical placement was achieved in five (33%) single-level and three (37.5%) dual-level disc replacements. Sub-optimal surgical placement was seen in nine (60%) single-level and five (62.5%) dual-level disc replacements. Poor surgical placement was observed in a single-level disc replacement. All patients demonstrated a reduction in objective pain score (P < 0.05). SF-36v2 outcomes were superior in single-level compared to dual-level and ideal compared to sub-optimal replacements (P < 0.05).

CONCLUSION

The hypothesis that ideal surgical placements are associated with improved clinical and functional outcomes in total lumbar disc replacement was confirmed.

Fragmentectomy versus Conventional Microdiscectomy in Single-Level Lumbar Disc Herniations : Comparison of Clinical Results and Recurrence Rates

Objective

This retrospective study aimed to compare clinical outcomes in terms of pain relief and recurrence rate between fragmentectomies and conventional microdiscectomies in patients with lumbar disc herniation (LDH).

Methods

Between January 2008 and May 2011, a total of 175 patients met the inclusion criteria of this study. The visual analogue scale (VAS) scores of back and radicular pains were recorded before surgery, 2 and 6 weeks after surgery. Recurrence was defined when a patient had the same pattern of preoperative symptoms and was confirmed with magnetic resonance imaging.

Results

Seventy-four patients (42.3%) were suitable for fragmentectomy, and 101 patients underwent conventional microdiscectomy. There were no significant differences in VAS scores between the fragmentectomy and conventional microdiscectomy groups 2 and 6 weeks after surgery. During the follow-up period, 3 patients (4.05%) in the fragmentectomy group and 7 patients (6.93%) in the conventional microdiscectomy group relapsed.

Conclusion

If patients are selected according to well-defined criteria, fragmentectomy can be a good surgical option for LDH, in the physiological aspect of preserving healthy intervertebral disc materials.

Clinical experience and results of lumbar microendoscopic discectomy: a study with a five-year follow-up

OBJECTIVE

To investigate the efficacy of microendoscopic discectomy (MED) for the treatment of lumbar disc herniation over a five-year follow-up period.

METHODS

Between January 2000 and December 2002, 275 patients were accepted for MED in our hospital. A retrospective review was carried out on 151 of these cases with a mean of five years follow-up. The study helped us to assess the efficacy of this technique in the treatment of lumbar disc diseases. Modified MacNab criteria were used to assess the clinical outcome, and the disc-height ratio was assessed radiographically according to the Mochida's method.

RESULTS

According to the modified MacNab criteria, 78.8% of patients were rated as excellent, 13.2% as good, 4.6% as fair, and 3.3% as poor. Complications included five revision surgeries due to recurrence of herniation, five dural lacerations during operation, and three cases of vertebral/disc infection. The average disc-height ratio was 76.25%. Approximately 57% of the patients maintained their primary engagement.

CONCLUSION

MED is both feasible and efficacious for the management of lumbar disc disease. On the basis of the present study it is concluded that MED is better than open discectomy (OD).

Full endoscopic contralateral transforaminal discectomy for distally migrated lumbar disc herniation

BACKGROUND

Discectomy of distally, inferiorly migrated disc herniations below midpedicle level of the vertebral body in the lower lumbar spine is known to be very difficult by endoscopy. The purpose of this study was to introduce the technical possibility of percutaneous endoscopic lumbar discectomy using a contralateral transforaminal approach for distally migrated disc herniation.

METHODS

We reviewed 12 patients who underwent percutaneous endoscopic lumbar discectomy using the contralateral transforaminal approach for distally migrated disc herniation. Complete removal was verified through postoperative magnetic resonance imaging (MRI) follow-up in all patients. Mean follow-up was 25 months.

RESULTS

Clinical results according to MacNab criteria were excellent in ten patients and good in two. Average visual analogue scale for lower back pain and radicular pain improved from 6.8 and 8.2 preoperatively to 1.5 and 1.4, postoperatively (p < 0.01, respectively).

CONCLUSION

Percutaneous endoscopic lumbar discectomy using contralateral transforaminal approach can be a useful method in patients with distally migrated disc herniation, and endoscopic navigation of anterior epidural space from the contralateral foramen in the lower lumbar spine is technically possible.

What happens to Modic changes following lumbar discectomy? Analysis of a cohort of 41 patients with a 3- to 5-year follow-up period

Object

The natural history of Modic changes (MCs) in the lumbar spine is often marked by conversion from one type to another, but their course following lumbar discectomy remains unknown. The authors sought to study the impact of surgery on the natural history of these lesions.

Methods

Forty-one patients treated with lumbar microdiscectomy between 2004 and 2005 were enrolled in this study and underwent clinical evaluation and repeat MR imaging after a median follow-up of 41 months (range 32–59 months). Preoperative and follow-up MR images were reviewed and the type, location, and extent of MCs at the operated level were recorded and compared.

Results

The study population consisted of 27 men and 14 women with a mean age of 54 years (range 24–78 years). During the follow-up period, the prevalence of MCs increased from 46.3% to 78%, and 26 patients (63.4%) had Type 2 lesions at the operated level. Of the 22 patients without MCs, 4 (18.2%) converted to Type 1 and 9 (40.9%) to Type 2. Of the 5 Type 1 lesions, 3 (60%) converted to Type 2, and 2 (40%) remained Type 1 but increased in size. In contrast, none of the 14 Type 2 changes converted to another type, although 10 (71.4%) increased in extent. There were no reverse conversions to Type 0.

Conclusions

Following lumbar discectomy, most patients develop Type 2 changes at the operated level, possibly as a result of accelerated degeneration in the operated disc. Neither the preoperative presence of MCs nor their postoperative course appears to affect the clinical outcome.

Clinical outcomes after posterior dynamic transpedicular stabilization with limited lumbar discectomy: Carragee classification system for lumbar disc herniations

BACKGROUND

The observed rate of recurrent disc herniation after limited posterior lumbar discectomy is highest in patients with posterior wide annular defects, according to the Carragee classification of type II (fragment-defect) disc hernia. Although the recurrent herniation rate is lower in both type III (fragment-contained) and type IV (no fragment-contained) patients, recurrent persistent sciatica is observed in both groups. A higher rate of recurrent disc herniation and sciatica was observed in all 3 groups in comparison to patients with type I (fragment-fissure) disc hernia.

METHODS

In total, 40 single-level lumbar disc herniation cases were treated with limited posterior lumbar microdiscectomy and posterior dynamic stabilization. The mean follow-up period was 32.75 months. Cases were selected after preoperative magnetic resonance imaging and intraoperative observation. We used the Carragee classification system in this study and excluded Carragee type I (fragment-fissure) disc herniations. Clinical results were evaluated with visual analog scale scores and Oswestry scores. Patients' reherniation rates and clinical results were evaluated and recorded at 3, 12, and 24 months postoperatively.

RESULTS

The most common herniation type in our study was type III (fragment-contained), with 45% frequency. The frequency of fragment-defects was 25%, and the frequency of no fragment-contained defects was 30%. The perioperative complications observed were as follows: 1 patient had bladder retention that required catheterization, 1 patient had a superficial wound infection, and 1 patient had a malpositioned transpedicular screw. The malpositioned screw was corrected with a second operation, performed 1 month after the first. Recurrent disc herniation was not observed during the follow-up period.

CONCLUSIONS

We observed that performing discectomy with posterior dynamic stabilization decreased the risk of recurrent disc herniations in Carragee type II, III, and IV groups, which had increased reherniation and persistent/continuous sciatica after limited lumbar microdiscectomy. Moreover, after 2 years' follow-up, we obtained improved clinical results.

Intradiscal electrothermal therapy for symptomatic internal disc disruption: 24-month results and predictors of clinical success

Object

Degeneration of the intervertebral disc can be the source of severe low-back pain. Intradiscal electrothermal therapy (IDET) is a minimally invasive treatment option for patients with symptomatic internal disc disruption unresponsive to conservative medical care. This study was undertaken in the neurosurgical setting to evaluate 24-month pain and functional outcomes and predictors of clinical success in patients with discogenic back pain treated with IDET.

Methods

Using MR imaging and discography findings, 50 patients with lumbar discogenic pain were identified, underwent IDET treatment, and were followed up for 24 months. Outcomes included assessments of back pain severity based on an 11-point numeric scale and back function based on the Oswestry Disability Index. The Prolo scale was applied to determine economic and functional status at 24 months.

Results

There was an average 68 and 66% improvement in back pain and function, respectively, between pretreatment and 24 months after treatment (p < 0.0001 for both comparisons). A maximum score of 5 on the Prolo scale for economic and functional status was achieved in 63 and 22% of patients, respectively. The global clinical success rate was 78% (39 of 50 patients) based on no reoperations at the affected level due to persistent symptoms, with a ≥ 2-point improvement in pain severity and a ≥ 15-point improvement in back function. Predictors of 24-month clinical success included discographic concordance (p < 0.0001), a high-intensity zone on MR imaging (p = 0.0003), low Pfirrmann grade (p = 0.0002), and more extensive anulus coverage (p < 0.0001). There were no procedure-related adverse events.

Conclusions

The findings of this study suggest that durable clinical improvements can be realized after IDET in highly select surgical candidates with mild disc degeneration, confirmatory imaging evidence of anular disruption, and highly concordant pain provocation on low-pressure discography.

Biomechanical testing of a polymer-based biomaterial for the restoration of spinal stability after nucleotomy

BACKGROUND

Surgery for disc herniations can be complicated by two major problems: painful degeneration of the spinal segment and re-herniation. Therefore, we examined an absorbable poly-glycolic acid (PGA) biomaterial, which was lyophilized with hyaluronic acid (HA), for its utility to (a) re-establish spinal stability and to (b) seal annulus fibrosus defects. The biomechanical properties range of motion (ROM), neutral zone (NZ) and a potential annulus sealing capacity were investigated.

METHODS

Seven bovine, lumbar spinal units were tested in vitro for ROM and NZ in three consecutive stages: (a) intact, (b) following nucleotomy and (c) after insertion of a PGA/HA nucleus-implant. For biomechanical testing, spinal units were mounted on a loading-simulator for spines. In three cycles, axial loading was applied in an excentric mode with 0.5 Nm steps until an applied moment of +/- 7.5 Nm was achieved in flexion/extension. ROM and NZ were assessed. These tests were performed without and with annulus sealing by sewing a PGA/HA annulus-implant into the annulus defect.

RESULTS

Spinal stability was significantly impaired after nucleotomy (p < 0.001). Intradiscal implantation of a PGA-HA nucleus-implant, however, restored spinal stability (p < 0.003). There was no statistical difference between the stability provided by the nucleus-implant and the intact stage regarding flexion/extension movements (p = 0.209). During the testing sequences, herniation of biomaterial through the annulus defect into the spinal canal regularly occurred, resulting in compression of neural elements. Sewing a PGA/HA annulus-implant into the annulus defect, however, effectively prevented herniation.

CONCLUSION

PGA/HA biomaterial seems to be well suited for cell-free and cell-based regenerative treatment strategies in spinal surgery. Its abilities to restore spinal stability and potentially close annulus defects open up new vistas for regenerative approaches to treat intervertebral disc degeneration and for preventing implant herniation.

Recurrent lumbar disc herniation after conventional discectomy: a prospective, randomized study comparing full-endoscopic interlaminar and transforaminal versus microsurgical revision

STUDY DESIGN

Prospective, randomized, controlled study of patients with recurrent lumbar disc herniations after conventional discectomy, operated either in a full-endoscopic or microsurgical technique.

OBJECTIVE

Comparison of results of lumbar revision discectomies in full-endoscopic interlaminar and transforaminal technique with the conventional microsurgical technique.

SUMMARY OF BACKGROUND DATA

Recurrences after lumbar disc operations cannot be prevented. Because of the existing scarring, the risk of intraoperative complications may be increased and consecutive damage may arise owing to greater traumatization. In disc surgery, tissue-sparing interventions are becoming more widespread. Endoscopic techniques have become the standard in many areas because of the advantages they offer intraoperatively and postoperatively. With the transforaminal and interlaminar techniques, 2 full-endoscopic procedures are available for the lumbar spine.

METHODS

Eighty-seven patients with recurrent herniation after conventional discectomy underwent full-endoscopic or microsurgical intervention and were followed for 2 years. In addition to general and specific parameters, the following measuring instruments were used: visual analog scale, German version of the North American Spine Society Instrument, Oswestry Low-Back Pain Disability Questionnaire.

RESULTS

Postoperatively, 79% of the patients no longer had leg pain, and 16% had occasional pain. The clinical results were the same in both groups. The re-recurrence rate was 5.7% with no difference between the groups. The full-endoscopic techniques brought significant advantages in the following areas: rehabilitation, complications, and traumatization.

CONCLUSIONS

The clinical results of the full-endoscopic technique are equal to those of the microsurgical technique. At the same time, there are advantages in the operation technique and reduced traumatization. With the surgical devices and the possibility of selecting an interlaminar or posterolateral to lateral transforaminal procedure, recurrent lumbar disc herniations can be sufficiently removed using the full-endoscopic technique. Full-endoscopic surgery is a sufficient and safe supplementation and alternative to microsurgical procedures.

Surgical treatment for lumbar lateral recess stenosis with the full-endoscopic interlaminar approach versus conventional microsurgical technique: a prospective, randomized, controlled study

OBJECT

Extensive decompression with laminectomy where appropriate is often still described as the method of choice in surgery for lateral recess stenosis. Nonetheless, tissue-sparing procedures are becoming more common. Endoscopic techniques have become the standard in many areas because of the advantages they offer in surgical technique and in rehabilitation. Transforaminal and interlaminar access provide 2 full-endoscopic (FE) techniques for lumbar spine surgery. The goal of this prospective randomized controlled study was to compare the surgical results for the FE technique via the interlaminar approach with those of the conventional microsurgical technique in patients with degenerative lateral recess stenosis.

METHODS

A total of 161 patients with FE or microsurgical decompression underwent follow-up for 2 years. In addition to general and specific parameters, the following measuring instruments were used: visual analog scale, German version of the North American Spine Society instrument, and the Oswestry low-back pain disability questionnaire.

RESULTS

The results show that 74.5% of patients reported no longer having leg pain, and 20.5% had only occasional pain. The clinical results were the same in both groups. The rate of complications and revisions was significantly reduced in the FE group. The FE techniques brought advantages in the following areas: operation, complications, traumatization, and rehabilitation.

CONCLUSIONS

The clinical results of the FE interlaminar technique are equal to those of the microsurgical technique. At the same time, there are advantages in the operation technique, such as reduced traumatization. The FE interlaminar spinal decompression procedure is a sufficient and safe supplement and alternative to microsurgical procedures.