Clinical effect of full endoscopic lumbar annulus fibrosus suture.

PURPOSE: The aim of this study was to investigate the clinical efficacy of full endoscopic lumbar annulus fibrosus suture in the treatment of single-segment lumbar disc herniation (LDH). METHODS: The clinical data of patients with single-segment LDH who underwent full endoscopic lumbar discectomy from January 2017 to January 2019 in our hospital were retrospectively analysed. Patients with full endoscopic lumbar discectomy combined with annulus fibrosus suture were divided into group A, and those with simple full endoscopic lumbar discectomy were divided into group B. The general information, surgery-related data, visual analog scale (VAS), Oswestry disability index (ODI), modified MacNab score at the last follow-up, reoperation rate and recurrence were compared between the two groups. RESULTS: All patients were followed up for 12 to 24 months, and the surgical time was 133.6 ± 9.6 min in group A and 129.0 ± 11.7 min in group B. The difference was not statistically significant (p > 0.05). The blood loss of group A was higher than that of group B, and the difference was statistically significant when comparing the groups (p < 0.05). The postoperative symptoms of patients in both groups were significantly relieved, and the VAS score of low back pain and ODI index were significantly lower than the preoperative ones at all postoperative time points (1 month after surgery, 3 months after surgery, and at the last follow-up) (p < 0.05), but there was no significant difference between the groups (p > 0.05). The excellent rate of MacNab at the last follow-up in the two groups were 93.55% and 87.80%, respectively, with no statistically significant difference (p > 0.05). At the last follow-up, the recurrence rate of group A was significantly lower than that of group B, and the difference was statistically significant (p < 0.05), while the difference between the reoperation rate of the two groups was not statistically significant (p > 0.05). CONCLUSIONS: Full endoscopic lumbar discectomy combined with annulus fibrosus repair reduces the postoperative recurrence rate and achieves satisfactory clinical outcomes.

Analysis of the clinical efficacy of visualization of percutaneous endoscopic lumbar discectomy combined with annulus fibrosus suture in lumbar disc herniation.

The objective of this study is to compare the clinical effectiveness of visualization of percutaneous endoscopic lumbar discectomy (VPELD) combined with annulus fibrosus suture technique and simple percutaneous endoscopic lumbar discectomy (PELD) technique in the treatment of lumbar disc herniation. A retrospective analysis was conducted on 106 cases of lumbar disc herniation treated with foraminoscopic technique at our hospital from January 2020 to February 2022. Among them, 33 cases were treated with VPELD combined with annulus fibrosus suture in group A, and 73 cases were treated with PELD in group B. The preoperative and postoperative visual analogue scale (VAS), functional index (Oswestry Disability Index, ODI), healing of the annulus fibrosus, intervertebral space height, and postoperative recurrence were recorded and compared between the two groups. All patients underwent preoperative and postoperative MRI examinations, and the average follow-up period was 12 ± 2 months. Both groups showed significant improvements in postoperative VAS and ODI scores compared to the preoperative scores (P < 0.05), with no statistically significant difference between the groups during the same period (P > 0.05). There was no significant decrease in intervertebral space between the two groups after surgery (P > 0.05). Group A showed significantly lower postoperative recurrence rate and better annulus fibrosus healing compared to group B (P < 0.05). The VPELD combined with annulus fibrosus suture technique is a safe, feasible, and effective procedure for the treatment of lumbar disc herniation. When the indications are strictly adhered to, this technique can effectively reduce the postoperative recurrence rate and reoperation rate. It offers satisfactory clinical efficacy and can be considered as an alternative treatment option for eligible patients.

Changes in Temperature Following Radiofrequency Thermal Ablation of the Nucleus Pulposus and Annulus Fibrosus: A Cadaveric Study.

BACKGROUND: Various minimally invasive procedures for treating discogenic pain have been reported in recent years. A Disc-FX® system can be used to perform nucleus pulposus (NP) removal, radiofrequency ablation, and annuloplasty under the guidance of x-ray fluoroscopy. However, when a probe tip with focused heat is placed on the intradiscal/subannular area to perform nucleo-annuloplasty using radiofrequency lesioning, thermal injury to the spinal cord or spinal nerves is a concern. OBJECTIVES: To assess the thermal profile generated by the Disc-FX ablation and modulation system in intervertebral discs from human cadaveric spine sections and evaluate the safety of its thermal dispersion function. STUDY DESIGN: A cadaveric study. METHODS: NP ablation and annulus fibrosus modulation were performed on a fresh human cadaveric lumbar spine intervertebral disc in a 36.5°C circulating water bath using radiofrequency. The 4 points from the center of the disc to one-third, two-thirds and the outer layer of the annulus were divided into 4 points, A-D, respectively, and radiofrequency lesions were performed on the 4 points. RESULTS: The temperature was increased upon irradiation. It fell slowly with the cessation of irradiation. The temperature was not significantly different between Turbo and Hemo mode at each point. The temperature was not significantly different among the 4 points at each mode. The average temperature of the ventral side of the dura mater was kept below 37°C. LIMITATIONS: The results of this study are limited due to the use of a cadaveric spine, which could not reflect the effect of soft tissue such as muscles and connective tissue around the disc. The position of the temperature measuring probe was relatively fixed. This cadaver demonstration was conducted at the L4-L5 level, which is mostly not restricted by the height of the iliac crest.  CONCLUSIONS: When performing NP ablation and annular modification, the epidural peripheral temperature should always be kept below 37°C. This preliminary in vitro research using human cadaveric discs showed that radiofrequency maintained the epidural space at a safe temperature during nucleo-annuloplasty.

[Early effectiveness of unilateral biportal endoscopic discectomy combined with annulus fibrosus suture in the treatment of lumbar disc herniation].

Objective: To analyze the early effectiveness of unilateral biportal endoscopic discectomy (UBED) combined with annulus fibrosus suture in the treatment of lumbar disc herniation (LDH). Methods: The clinical data of 19 patients with LDH treated with UBED and annulus fibrosus suture between October 2020 and October 2021 were retrospectively analyzed. There were 12 males and 7 females with an average age of 39.1 years (range, 26-59 years). The operative segment was L 4, 5 in 13 cases, and L 5, S 1 in 6 cases. The mean disease duration was 6.7 months (range, 3-15 months). Preoperative neurological examination showed that muscle strength, sensation, and tendon reflex weakened or disappeared in varying degrees. Single annulus fibrosus suture (14 cases) or anchor assisted annulus fibrosus suture (5 cases) was selected according to the location of annulus fibrosus tears. Visual analogue scale (VAS) score was used to assess the low back and leg pain before operation and at 3 days, 3 months, and 6 months after operation. Oswestry disability index (ODI) was used to evaluate the function recovery of lumbar spine before operation and at 3 days, 3 months, and 6 months after operation. At 3 days and 3 months after operation, MRI was used to examine the removal of nucleus pulposus and decompression of nerve root. MacNab criteria was used to evaluate the effectiveness at 6 months after operation and the recovery of nerve root function was recorded. Results: All operations were successfully completed with a mean operation time of 52.7 minutes (range, 40-75 minutes). There was no complication such as nerve injury, spinal cord hypertension syndrome, or dural sac tear during operation, and no complication such as infection, aggravation of nerve damage, or cerebrospinal fluid leakage after operation. All the patients were followed up 6-10 months (mean, 8.2 months). Postoperative MRI showed that the herniated disc was completely removed and nerve roots were fully decompressed. During the follow-up, there was no recurrence of disc herniation. The VAS scores of low back pain and leg pain and ODI at each time point after operation significantly improved when compared with those before operation, and those at 6 months after operation further improved than those at 3 days and 3 months after operation, all showing significant differences ( P<0.05). At 6 months after operation, MacNab standard was used to evaluate the effectiveness, and the results were excellent in 14 cases, good in 4 cases, and fair in 1 case, with an excellent and good rate of 94.7%. Neurological examination showed that the sensation and muscle strength of the affected nerve root innervated area recovered significantly when compared with those before operation ( P<0.05); the recovery of tendon reflex was not obvious, showing no significant difference when compared with that before operation ( P>0.05). Conclusion: UBED combined with annulus fibrosus suture is a safe and effective technique for LDH and early effectiveness is satisfactory.

Regenerating and repairing degenerative intervertebral discs by regulating the micro/nano environment of degenerative bony endplates based on low-tension mechanics.

BACKGROUND: Conservative treatment is the recommended first-line treatment for degenerative disc diseases. Traction therapy has historically been one of the most common clinical methods to address this, but the clinical effect remains controversial. METHODS: Forty-two six-month-old male Sprague-Dawley rats were randomly divided into six groups: the model group (Group A, four coccyx vertebrae (Co7-Co10) were fixed with customized external fixators, and the vertebral disc degeneration model was constructed by axial compression of the target segment Co8 - Co9 for 4 weeks), the experimental control group (Group B, after successful modeling, the external fixation device was removed and self-rehabilitation was performed) and four intervention groups (Groups C to F): Groups C and E: Co8 - Co9 vertebrae compressed for 4 weeks followed by two or 4 weeks of high tension traction (HTT), respectively, and Groups D and F: vertebrae compressed for 4 weeks followed by two or 4 weeks of low-tension traction (LTT), respectively. Imaging tests (X-ray and MRI) were performed to assess disc height and T2 signal intensity at each time point. After the experiment, the animals were euthanized, and the caudal vertebrae were collected for analysis of intervertebral disc histopathology, proteoglycan content, and micronanostructure of the annulus fibrosus, nucleus pulposus and bony endplate. RESULTS: Signs of tissue regeneration were apparent in all four intervention groups. After two to 4 weeks of intervention (HTT and LTT), the morphology of pores in the bony endplate, their number, and diameter had recovered significantly compared with those in Group A. The LTT group was superior to the HTT group, and the 4w in situ group was significantly superior to the 2w group. Meanwhile, the histological scores of discs, the mean fibril diameter and modulus of annulus fibrosus were significantly improved compared with the control groups, and the LTT group was superior to HTT group. CONCLUSIONS: Low-tension traction better promotes active reconstruction of bony endplates and improves the elastic modulus and micro/nanostructure of the disc. Thus, it further promotes the regeneration and repair of intervertebral discs.

Lumbar discectomy with annulus fibrosus closure: A retrospective series of 53 consecutive patients.

INTRODUCTION: Lumbar disc herniation is most common degenerative alteration of the spine. Whenever surgical therapy proves to be necessary, recurrent disc herniation is most frequent concern. Here, primary aim was to determine the percentage of patients eligible for insertion of an annular closure device (ACD). Secondary aim to evaluate 12-month incidence of recurrent disc herniation at the operated level. Our hypothesis was that ACD might help in preventing recurrent disc herniation. METHODS: Patients in a single Swiss neurosurgical center underwent limited discectomy alone (n=41, group 1) versus limited discectomy plus ACD (n=12, group 2). Mean postoperative follow-up period was 12months. RESULTS: Twelve out of 53 patients (22.6%) were eligible for ACD implantation. Patients of group 2 were significantly taller (mean 176cm, P=0.007) as compared with group 1 (mean 170). The only statistically significant difference of intraoperative parameters between group 1 and 2 was amount of nucleus materiel removed (P=0.01), being greater in group 2 (mean 0.9) as compared with group 1 (mean 0.3). In group 1 six patients (6/41, 14.6%) presented with symptomatic reherniation at same level of surgery, while in group 2 only one patient experienced recurrence (1/12, 8.3%). No adverse events were reported. DISCUSSION: In the current study one out of five patients with lumbar disc herniation was considered suitable for ACD placement. In vast majority of these patients reherniation was precluded on the short-term basis. Patients with ACD were taller and had intraoperatively a higher volume of the nucleus pulposus materiel removed.

Selective Retention of Bone Marrow Stromal Cells with Gelatin Sponge for Repair of Intervertebral Disc Defects after Microendoscopic Discectomy: A Prospective Controlled Study and 2-Year Follow-Up.

OBJECTIVE: Discectomy remains the classic procedure for treating lumbar intervertebral disc (IVD) herniation, but the occurrence of defects after discectomy is thought to be an important cause generating recurrent and accelerated IVD degeneration. Previous studies attempted suture of the annulus fissure, but the validity of this technique on restraining the degenerative process is controversial. On the other hand, cell therapies have been shown in multiple clinical and basic studies. Our purpose was to investigate the effectiveness of selective retention of autologous Bone Marrow Stromal Cells (BMSCs) with gelatin sponge in combination with annulus fibrosus suture (AFS) for the repair of IVD defects following mobile microendoscopic discectomy (MMED). METHODS: This prospective, two-armed, and controlled clinical study was conducted from December 2016 to December 2018. Written informed consent was obtained from each patient. Forty-five patients with typical symptoms, positive signs of radiculopathy, and obvious lumbar disc herniation observed by MRI were enrolled. Patients were divided into 3 groups with different treating methods: MMED (n = 15), MMED+AFS (n = 15), and MMED+AFS+BMSCs (n = 15). A postoperative 2-year follow-up was performed to evaluate the patient-reported outcomes of VAS, ODI, and SF-36. The improvement rate of VAS and ODI was calculated as [(latest-preoperative)/preoperative] to evaluate the therapeutic effect of the three groups. Assessment parameters included Pfirrmann grade, intervertebral disc height (IDH), and disc protrusion size (DPS), as measured by MRI to evaluate the morphological changes. RESULTS: All patients enrolled had a postoperative follow-up at 3, 6, 12, and 24 months. VAS and ODI scores were significantly improved compared to the preoperative status in all three groups with a mean DPS reduction rate over 50%. At the final follow-up, the improvement rate of the VAS score in the MMED+AFS+BMSCs group was significantly higher than the MMED+AFS and MMED groups (80.1% ± 7.6% vs. 71.3% ± 7.0% vs. 70.1% ± 7.8%), while ODI improvement showed a significant change (65.6% ± 8.8% vs. 59.9% ± 5.5% vs. 57.8% ± 8.1%). All participants showed significant improvement in SF-36 PCS and MCS; the differences between each group were not significant. The mean IDH loss rate of the MMED+AFS+BMSCs group was also significantly lower than other groups (-17.2% ± 1.3% vs. -27.6% ± 0.7% vs. -29.3% ± 2.2%). The Pfirrmann grade was aggravated in the MMED and MMED+AFS groups while maintained at the preoperative grade in the MMED+AFS+BMSCs group. No adverse events of cell transplantation or recurrence were found in all patients during the postoperative follow-up period. CONCLUSIONS: It is feasible and effective to repair lumbar IVD defects using SCR-enriched BMSCs with gelatin sponges, which warrants further study and development as a cell-based therapy for IVD repair.

3D virtual reconstruction and quantitative assessment of the human intervertebral disc's annulus fibrosus: a DTI tractography study.

The intervertebral disc's (IVD) annulus fibrosus (AF) retains the hydrostatic pressure of the nucleus pulposus (NP), controls the range of motion, and maintains the integrity of the motion segment. The microstructure of the AF is not yet fully understood and quantitative characterization is lacking, leaving a caveat in modern medicine's ability to prevent and treat disc failure (e.g., disc herniation). In this study, we show a reconstruction of the 3D microstructure of the fibers that constitute the AF via MRI diffusion tensor imaging (DTI) followed by fiber tracking. A quantitative analysis presents an anisotropic structure with significant architectural differences among the annuli along the width of the fibrous belt. These findings indicate that the outer annuli's construction reinforces the IVD while providing a sufficient degree of motion. Our findings also suggest an increased role of the outer annuli in IVD nourishment.

Gelatin-Poly (γ-Glutamic Acid) Hydrogel as a Potential Adhesive for Repair of Intervertebral Disc Annulus Fibrosus: Evaluation of Cytocompatibility and Degradability.

STUDY DESIGN: An in vitro experimental study testing a Gelatin-poly (γ-glutamic acid) hydrogel for disc repair. OBJECTIVE: To evaluate the cytocompatibility and degradability of the above mentioned hydrogel for intervertebral disc annular fibrosis (AF) repair. SUMMARY OF BACKGROUND DATA: No repair strategies for correcting annular defects in lumbar discectomy have been clinically well recognized. Exogenous supplementation of regenerative materials to fill defects is a minimally invasive way to restore compromised mechanical properties. The injected materials, most commonly gelatin-based materials with cross-linking agents, serve as sealants and as a scaffold for incorporating biomaterials for augmentation. However, cytotoxicity of hydrogel crosslinking agents is of concern in developing viable materials. METHODS: This in vitro experimental study evaluated a newly developed gelatin-based hydrogel for intervertebral disc AF repair. Mechanical strength was augmented by γ-PGA, and 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (EDC) was used for material crosslinking. Isolated bovine tail intervertebral discs (IVDs) were used to test the hydrogel, and hydrogel surface monolayer AF cell culture was used to investigate efficacy in hydrogel constructs of different EDC concentrations. Cell metabolic activity was evaluated with Alamar blue assay, cell viability assay with live/dead stain, and sulfated glycosaminoglycan (GAG) and double strain DNA were quantified to evaluate proliferation of implanted cells and synthesis of extracellular matrix (ECM) proteins. RESULTS: EDC concentrations from 10 to 40 mM resulted in significant decreases in AF cell proliferation without obvious influence on cell viability. Higher EDC concentrations resulted in decreased percentage of Alamar blue reduction and GAG and DNA concentration, but did not affect GAG/DNA and live-dead ratios. Degradation tests revealed that higher EDC concentrations decreased the hydrogel degradation rate. CONCLUSION: The developed gelatin-poly (γ-PGA) hydrogel with 20 mM EDC concentration provides an effective gap-filling biomaterial with good cytocompatibility, suggesting substantial promise for use as a sealant for small AF defects.Level of Evidence: N/A.

A Pilot Study of Full-Endoscopic Annulus Fibrosus Suture Following Lumbar Discectomy: Technique Notes and One-Year Follow-Up.

BACKGROUND: An annulus fissure or defect will inevitably be left on the posterior annulus fibrosus after almost all kinds of lumbar discectomy, which may lead to unsatisfying postoperative pain relief and recurrence of the disc herniation. OBJECTIVE: The objective of this research is to introduce the technique of full-endoscopic annulus fibrosus suture following lumbar discectomy through the transforaminal or interlaminar approach, and to analyze the clinical outcome of full-endoscopic lumbar discectomy and annulus fibrosus suture. STUDY DESIGN: This study used a prospective cohort design. SETTING: The research was conducted in a hospital and outpatient surgery center. METHODS: A total of 50 patients with noncontained lumbar disc herniation treated with full-endoscopic lumbar discectomy and annulus fibrosus suture were treated in our department between January 2018 and November 2018. Full-endoscopic single-stitch suture via the transforaminal approach (Group T) or double-stitch suture via the interlaminar approach (Group I) was selected according to the level of lesion. Lumbar magnetic resonance imaging (MRI) was reexamined on the second day and 3 months after operation to evaluate the completeness of the discectomy and the adequacy of nerve decompression. Patients were followed up on the second day, 3 months, 6 months, and one year after operation to evaluate the relief of low back pain and leg pain, using a visual analog scale (VAS, 100-point scale). At 3 months, 6 months, and one year after operation, the patients were followed up for recovery of lumbar spine function, using the Oswestry Disability Index (ODI). At the one-year follow-up, the MacNab score was used to evaluate the clinical outcome, and the recovery of nerve root function (sensation, muscle strength, and reflex) was recorded. RESULTS: All operations were successfully completed, including 27 cases in Group T and 23 cases in Group I. There were no surgical complications and no recurrence of lumbar disc herniation. Lumbar MRI reexaminations of all patients showed that the herniated disc was completely removed and the nerves were fully decompressed. Postoperative low back pain and leg pain were significantly relieved, and the ODI score was significantly improved (P < .01) in both groups. At the one-year follow-up, the excellent and good rates as measured by the MacNab score were 92.6% in Group T and 91.3% in Group I with no significant difference between the 2 groups (P > .05). The impaired sensation and muscle strength in the low extremities of evolved nerve root of the 2 groups of patients recovered significantly at the one-year follow-up (P < .01), but the tendon reflex did not recover significantly (P > .05). LIMITATIONS: This is an observational cohort study with relatively small sample sizes and short-term follow-up. CONCLUSIONS: Full-endoscopic lumbar discectomy and annulus fibrosus suture through either the transforaminal or interlaminar approach are safe and effective minimally invasive spinal surgery techniques that can reduce the recurrence rate of lumbar disc herniation after full-endoscopic lumbar discectomy.

Melatonin activates autophagy via the NF-κB signaling pathway to prevent extracellular matrix degeneration in intervertebral disc.

OBJECTIVE: This study investigated whether melatonin alleviates intervertebral disc degeneration (IVDD) by promoting autophagy through inhibiting the NF-κB signaling pathway. METHODS: Magnetic resonance imaging (MRI), hematoxylin and eosin (H&E) staining and Safranin-O staining were used to measure disc degeneration in rat needle puncture IVDD models, and melatonin was injected intraperitoneally in the treated group to test its function. The expression of autophagy and extracellular matrix (ECM) degeneration related-markers were measured in the discs using immunohistochemistry. Transmission electron microscopy was used to evaluate the activation of autophagy in human nucleus pulposus (NP) tissues with different degenerated statuses. The expression of autophagy and disc degeneration related-markers were detected in NP cells by Western blot, RT-qPCR, and immunofluorescence analyses. NF-κB signaling pathway involvement was studied by lentivirus-mediated knockdown, Western blotting, and immunohistochemistry and immunofluorescence staining. RESULTS: Melatonin prevented IVDD development in vivo and in vitro. Compared to non-degenerated disc tissues, degenerated human NP tissues showed a decrease in the autophagy-specific marker LC3B and the numbers of autophagosomes and autolysosomes, whereas the p62 level was increased; similar results were observed in rat IVDD models, indicating a negative correlation between autophagy and IVDD. Furthermore, both in vivo and in vitro studies found that melatonin application induced autophagy and reduced ECM disc degradation. Melatonin was also shown to regulate autophagy by inhibiting the NF-κB signaling pathway in vivo and vitro. CONCLUSION: This study indicates that melatonin prevents IVDD by promoting autophagy, indicating its possible therapeutic potential for controlling the progression of IVDD.

Nucleus replacement could get a new chance with annulus closure.

PURPOSE: Disc herniations are usually treated by decompression of the spinal nerves via a partial nucleotomy. As a consequence of reduced disc height (DH), reduced intradiscal pressure (IDP) and increased range of motion (ROM), accelerated degeneration may occur. Nucleus replacement implants are intended to restore those values, but are associated with the risk of extrusion. METHODS: In six fresh frozen lumbar spinal segments (L2-3/L3-4/L4-5/L5-S1, age median 64.5 years (57-72), Pfirrmann grade 2-3), a prolapse was provoked through a box defect (6 × 10 mm) in the annulus. The herniated nucleus material was removed and replaced by a novel collagen-based nucleus implant. An annulus closure device sealed the defect. ROM, neutral zone (NZ) and IDP were measured in the (1) intact and (2) defect state, (3) postoperatively and (4) after cyclic loading (n = 100,000 cycles) applying pure moments (± 7.5 Nm) in flexion-extension, lateral bending and axial rotation. Additionally, the change in DH was determined. Extrusion of implants or nucleus material was evaluated macroscopically. RESULTS: In all specimens, a prolapse could be provoked which decreased DH. Subsequent nucleotomy changed ROM/NZ and IDP considerably. Initial values could be restored by the implantation. Macroscopically, none of the implants nor nucleus material did migrate after cyclic loading. CONCLUSIONS: In this study, a prolapse followed by a nucleotomy resulted in a biomechanical destabilisation. Implantation of the nucleus replacement combined with an annulus closure restored the intact condition without showing signs of extrusion nor migration after cyclic loading. Hence, nucleus replacements could have a new chance in combination with annulus closure devices.

Could the Splitting of the Annulus During Percutaneous Endoscopic Lumbar Diskectomy (PELD) Be a Culprit for Recurrent Disk Herniation?: An Analysis of the Reherniation Pattern After PELD.

OBJECTIVE: To explore which preoperative radiologic variables have propensity for reherniation and to evaluate whether the inherent annulus splitting procedure during percutaneous endoscopic lumbar diskectomy (PELD) could prompt reherniation, we assessed the correlation between the anatomic location of annular penetration and reherniation. METHODS: Three hundred and fifty patients who underwent PELD for central or subarticular disk herniation through a transforaminal approach were followed-up for at least 24 months. Fifty-four subjects that were reoperated for recurrent herniation were allocated as the reherniation group and the other 296 subjects were allocated as the non-reherniation group. The numerical rating scale score, another lumbosacral disk herniation (LDH) lesion in addition to the PELD level (another LDH), location (central or subarticular) and severity of LDH (protrusion or extrusion), and tear of the posterior longitudinal ligament (PLL) were compared between the 2 groups to identify which variables could be predictive factors for reherniation. To assess the influences of PELD on reherniation, location and severity of reherniation were compared with those of initial herniation. RESULTS: The location at the subarticular region and the existence of a concomitant PLL tear during initial LDH were significantly related to subsequent reherniation. The location and severity of these reherniations were significantly retained when compared with those of primary herniation. CONCLUSIONS: PLL tear and subarticular herniation were significantly related to recurrent disk herniation. Reherniation patterns after PELD generally matched those of primary herniation. The annulus penetrating step during PELD did not increase the risk of reherniation.

A Heterologous Fibrin Glue Enhances the Closure Effect of Surgical Suture on the Repair of Annulus Fibrous Defect in a Sheep Model.

Improving the closure effect of surgical suture for repair of annulus fibrosus defects remains an unsolved problem. A new type of porcine fibrin glue was reported for the repair of annulus fibrous defects in sheep models in this study. Continuous axial loading test showed that this glue could effectively improve the closure effect of surgical suture for annulus fibrous defect. Magnetic resonance imaging (MRI) of the lumbar spine confirmed that, compared with non-fibrin glue treated intervertebral discs, it contributed to preservation of the nucleus pulposus and maintained the physiological hydration of the intervertebral discs. Moreover, histomorphology evaluation showed that the porcine fibrin glue could partially reverse degeneration of the injured intervertebral discs. Taken together, porcine fibrin glue can effectively enhance the closure effect of surgical suture on annulus fibrosus, improve the repair effect and slow down the degeneration of the intervertebral disc, and provide a potential therapeutic strategy for degenerative intervertebral disc disease.

Surgical Experience and Complications in 50 Patients Treated with an Anular Closure Device Following Lumbar Discectomy.

OBJECTIVE: To examine the results of an anular closure device for prevention of lumbar disc reherniation in daily routine practice. METHODS: Fifty patients with large anular defects were treated with limited discectomy and a bone-anchored anular closure device. The device physically occludes the defect in the anulus fibrosus and is intended for prevention of lumbar disc reherniation. Pain scores on a visual analogue scale, back function on the Oswestry Disability Index, and neurological status were noted. Symptomatic reherniation and reoperation rates were assessed at each follow-up. Surgical findings and complications, device-related and/or procedure-related, were recorded. Follow-up was 6, 12, 26, and 52 weeks. RESULTS: Mean anular defect height/width was 4.6 mm/10.1 mm. The overall symptomatic reherniation and reoperation rate was 2%. During the 1-year follow-up period, mean back pain decreased from 43 to 8 (P < 0.001), leg pain decreased from 71 to 4 (P < 0.001), and the Oswestry Disability Index decreased from 46 to 5 (P < 0.001). Among 15 patients with preoperative neurological deficits, improvements in neurological function were noted in 14 (93%). There were no serious device-related complications. CONCLUSIONS: The presented study shows promising early results in using the anular closure device. The procedure is safe with significantly fewer reherniations than for patients with large anular defects without anular closure. Further studies with longer follow-up periods are warranted to prove these findings for long-term outcomes.

Using Percutaneous Endoscopic Outside-In Technique to Treat Selected Patients with Refractory Discogenic Low Back Pain.

BACKGROUND: Controversy is not uncommon in the diagnosis of discogenic low back pain (DLBP) and in the identification of the location of the pain source for the symptomatic disc in patients with DLBP. Various techniques, from minimally invasive procedures to fusion surgery, are used to treat chronic DLBP, but the clinical outcomes are variable. Percutaneous endoscopic discectomy by transforaminal or interlaminar approach is considered to be an effective method to treat DLBP, but the evidence is limited; the lack of clear evidence may be associated with patient selection and surgical technique. OBJECTIVES: The purpose of this study is to evaluate the clinical results of percutaneous endoscopic treatment for annular tear in selected patients with DLBP by using the outside-in technique. STUDY DESIGN: A prospective study and retrospective observations were performed on 24 consecutive patients with a minimum 2 years of follow-up. This study was approved by the Institutional Review Board (IRB) of Buddhist Dalin Tzu-Chi General Hospital Foundation (IRB number: 10504004) and written informed consent was obtained from all patients. SETTING: This research took place within an interventional pain management and spine practice. METHODS: Twenty-four consecutive patients with single-level DLBP diagnosed by positive high-intensity zone on magnetic resonance imaging, positive provocative discography, and block test underwent a percutaneous endoscopic procedure from January 2014 to December 2015. The transforaminal approach or interlaminar approach was selected according to the location of the annular tear. The torn lesions were visualized directly and treated by puncture and debridement of the inflammatory tissues from the outer annulus fibrosus to the inner nucleus using the outside-in technique. The Visual Analog Scale (VAS) score and Oswestry Disability Index (ODI) score were evaluated before and after surgery. The clinical global outcomes were assessed on the basis of modified MacNab criteria. RESULTS: These patients included 13 men and 11 women with a mean age of 43.8 years (range, 32-55 yrs). There were 15 lesion levels at L4/L5 and 9 lesion levels at L5/S1. Among them, 15 levels were accessed by transforaminal approach and 9 levels by interlaminar approach. No serious complications were observed during the follow-up periods. All except 2 patients experienced significant symptomatic and functional improvements at the 2-year follow-up with a success rate of 91.7%. LIMITATIONS: Significant limitations include nonrandom format and small sample size. Future research may focus on controlled prospective studies with larger sample sizes and long-term follow-up to examine the validity of this protocol. CONCLUSIONS: The percutaneous endoscopic procedure provides a safe and effective treatment for selected patients with DLBP. The outside-in technique allows the surgeons to visualize and treat the torn or inflammatory lesions directly, and the success rate is high at 2 years follow-up. KEY WORDS: Transforaminal, interlaminar, outside-in technique, endoscopic discectomy, discogenic low back pain.

Comparative analysis of the intervertebral disc signal and annulus changes between immediate and 1-year postoperative MRI after transforaminal endoscopic lumbar discectomy and annuloplasty.

PURPOSE: Postoperative magnetic resonance imaging (MRI) after microdiscectomy for lumbar disc herniation frequently shows spinal canal compression by the remaining annulus, which gradually decreases over time. Transforaminal endoscopic lumbar discectomy (TELD) can remove the herniation with minimal trauma to surrounding soft tissue. We aim to identify this remodeling of annulus fibrosus and the change of disc signal after TELD. METHODS: We reviewed patients who underwent TELD. Clinical data obtained were Oswestry disability index (ODI) and visual analog scale (VAS) for back and leg pain. Residual mass signal and disc protrusion size were measured in postoperative MRI. RESULTS: Thirty-one patients were reviewed. The mean age was 38.3 ± 14.4 years (range 18 to 76 years). ODI was 18.2% at the first follow-up and 12.7% at the last follow-up (p = 0.009). VAS for back and leg pain were 2.0 and 1.0 without significant change during follow-up. Disc protrusion size was reduced by 67.7% at the 1-year follow-up (p < 0.001). The residual mass signals at postoperative day 1 were high in 12 cases, intermediate in 18 cases, and low in1 case. The signal intensity was correlated with the percentage of disc protrusion reduction (p = 0.048). The percentage of disc protrusion reduction correlated with the last follow-up ODI (p = 0.018). CONCLUSION: One year after TELD, annulus remodeling was observed with an average of 67.7% of size reduction. The high signal intensity of residual mass at day 1 correlated with disc protrusion reduction at follow-up MRI. The percentage of disc protrusion reduction associated with the ODI at the final follow-up.

Thermal Annuloplasty Using Percutaneous Endoscopic Discectomy for Elite Athletes with Discogenic Low Back Pain.

The purpose of this study was to assess the usefulness of radiofrequency thermal annuloplasty (TA) using percutaneous endoscopic discectomy/TA (PED/TA) in elite athletes with discogenic low back pain. Twelve patients (11 men, 1 woman; mean age 27.9 years) underwent PED/TA under local anesthesia. Clinical data for these patients (17 affected intervertebral discs), including type of sport played, average duration of low back pain, disc level affected, presence or absence of a high signal intensity zone on magnetic resonance imaging, and whether the patient returned to playing competitive sport, were retrospectively reviewed. The most common sport played by the patient was baseball (n = 8), followed by cycling (n = 2), tennis (n = 1), and hammer throw (n = 1). The average duration of low back pain was 24.3 months. The intervertebral disc levels affected were L4/5 (n = 11) and L5/S1 (n = 6). A high signal intensity zone was detected in nine discs. Although two patients required additional surgery, all patients were able to return to their original competitive level of play. Duration for the return to play was 2.8 months after surgery except the two revision cases. PED/TA for discogenic pain enables an early return to competitive sports, and so is particularly useful for elite athletes.

Mesenchymal Stem Cell-Seeded High-Density Collagen Gel for Annular Repair: 6-Week Results From In Vivo Sheep Models.

BACKGROUND: Our group has previously demonstrated in vivo annulus fibrosus repair in animal models using an acellular, riboflavin crosslinked, high-density collagen (HDC) gel. OBJECTIVE: To assess if seeding allogenic mesenchymal stem cells (MSCs) into this gel yields improved histological and radiographic benefits in an in vivo sheep model of annular injury. METHODS: Fifteen lumbar intervertebral discs (IVDs) were randomized into 4 groups: intact, injury only, injury + acellular gel treatment, or injury + MSC-seeded gel treatment. Sheep were sacrificed at 6 wk. Disc height index (DHI), Pfirrmann grade, nucleus pulposus area, and T2 relaxation time (T2-RT) were calculated for each IVD and standardized to healthy controls from the same sheep. Quantitative histological assessment was also performed using the Han scoring system. RESULTS: All treated IVDs retained gel plugs on gross assessment and there were no adverse perioperative complications. The MSC-seeded gel treatment group demonstrated statistically significant improvement over other experimental groups in DHI (P = .002), Pfirrmann grade (P < .001), and T2-RT (P = .015). There was a trend for greater Han scores in the MSC-seeded gel-treated discs compared with injury only and acellular gel-treated IVDs (P = .246). CONCLUSION: MSC-seeded HDC gel can be delivered into injured IVDs and maintained safely in live sheep to 6 wk. Compared with no treatment and acellular HDC gel, our data show that MSC-seeded HDC gel improves outcomes in DHI, Pfirrmann grade, and T2-RT. Histological analysis shows improved annulus fibrosus and nucleus pulposus reconstitution and organization over other experimental groups as well.

A percutaneous, minimally invasive annulus fibrosus needle puncture model of intervertebral disc degeneration in rabbits.

PURPOSE: Various animal models have been proposed to mimic the pathophysiologic process of intervertebral disc degeneration, a leading cause of back pain. The purpose of this study is to describe a minimally invasive technique via percutaneous needle puncture of the annulus fibrosus in New Zealand white rabbits. METHODS: Under fluoroscopic guidance, an 18-gauge spinal needle was inserted 2 cm lateral to the midline spinous process. The needle was slowly advanced at approximately 45° angle until it was adjacent to the L5/L6 disc space. Lateral and anteroposterior views were used to verify correct needle position before advancing into the nucleus pulposus. The rabbits underwent weekly X-rays for 4 weeks to assess disc height index. MRI T2 relaxation was evaluated at week four to assess morphological changes. Discs were histologically graded on a 12-point scale to assess degeneration and compared to discs obtained from uninjured rabbits. RESULTS: There were no complications associated with the percutaneous needle puncture procedure. All animals survived the duration of the experiment. Four weeks after injury, the disc height had progressively narrowed to approximately 50% of baseline. MRI assessment at the 4-week time point demonstrated a mean T2 relaxation time at the L5/L6 level that was 20.9% of the T2 relaxation time at the uninjured L4/L5 disc level ( p < 0.001). Histological analysis demonstrated lamellar disorganization of the annulus and decreased cellularity and proteoglycan content within the injured nucleus compared to uninjured control discs. CONCLUSION: The present study demonstrated a reliable technique of inducing an annular tear via a percutaneous needle puncture. Compared to open surgical approaches, the percutaneous model produces similar progressive disc degeneration while minimizing harm to the animal subjects. CLINICAL RELEVANCE: The present study establishes a technique for the introduction of novel therapeutic agents to treat disc degeneration that may translate to future clinical trials.