Restore Disc Height Research Articles

Efficacy of administered mesenchymal stem cells in the initiation and co-ordination of repair processes by resident disc cells in an ovine (Ovis aries) large destabilizing lesion model of experimental disc degeneration.

BackgroundForty percent of low back pain cases are due to intervertebral disc degeneration (IVDD), with mesenchymal stem cells (MSCs) a reported treatment. We utilized an ovine IVDD model and intradiscal heterologous MSCs to determine therapeutic efficacy at different stages of IVDD.MethodologyThree nonoperated control (NOC) sheep were used for MSC isolation. In 36 sheep, 6 × 20 mm annular lesions were made at three spinal levels using customized blades/scalpel handles, and IVDD was allowed to develop for 4 weeks in the Early (EA) and late Acute (LA) groups, or 12 weeks in the chronic (EST) group. Lesion IVDs received injections of 10 × 106 MSCs or PBS, and after 8 (EA), 22 (LA) or 14 (EST) weeks recuperation the sheep were sacrificed. Longitudinal lateral radiographs were used to determine disc heights. IVD glycosaminoglycan (GAG) and hydroxyproline contents were quantified using established methods. An Instron materials testing machine and customized jigs analyzed IVD (range of motion, neutral zone [NZ] and stiffness) in flexion/extension, lateral bending and axial rotation. qRTPCR gene profiles of key anabolic and catabolic matrix molecules were undertaken. Toluidine blue and hematoxylin and eosin stained IVD sections were histopathologically scoring by two blinded observers.ResultsIVDD significantly reduced disc heights. MSC treatment restored 95% to 100% of disc height, maximally improved NZ and stiffness in flexion/extension and lateral bending in the EST group, restoring GAG levels. With IVDD qRTPCR demonstrated elevated catabolic gene expression (MMP2/3/9/13, ADAMTS4/5) in the PBS IVDs and expession normalization in MSC‐treated IVDs. Histopathology degeneracy scores were close to levels of NOC IVDs in MSC IVDs but IVDD developed in PBS injected IVDs.DiscussionAdministered MSCs produced recovery in degenerate IVDs, restored disc height, composition, biomechanical properties, down regulated MMPs and fibrosis, strongly supporting the efficacy of MSCs for disc repair.

Comparing stand-alone oblique lumbar interbody fusion with posterior lumbar interbody fusion for revision of rostral adjacent segment disease: A STROBE-compliant study.

Spinal fusion has become a standard treatment for symptomatic intervertebral degenerative disc disease. The present study aimed to compare perioperative parameters, clinical outcomes, and radiographic results of stand-alone oblique lumbar interbody fusion (OLIF) with posterior lumbar interbody fusion (PLIF) for the revision of rostral adjacent segment disease (ASD) following prior posterior lumbar fusion.Thirty-six patients who underwent revision surgeries for rostral ASD were retrospectively reviewed. Among them, 17 patients underwent stand-alone OLIF (OLIF group) and 19 patients underwent PLIF (PLIF group). The length of operation, intraoperative hemorrhage, bed rest duration, and length of hospital stay were compared between the 2 groups. Clinical results were evaluated with the Oswestry Disability Index (ODI) and visual analog scale (VAS). Radiological results were evaluated with disc height (DH), foraminal height (FH), retrolisthesis index (RI), and lumbar lordosis (LL), as well as the fusion rate and cage subsidence. Follow-up results at 1 week, 3 months, and 12 months postoperatively were compared between the 2 groups.The OLIF group had less intraoperative blood loss, shorter operative time, bed rest time, and hospital stay than did the PLIF group (P < .05). The OLIF group had lower VAS scores for back pain than the PLIF group at 1 week and 3 months postoperatively (P < .05), and lower VAS scores for leg pain than the PLIF group at 1 week postoperatively (P < .05). The OLIF group had lower ODI than the PLIF group at 1 week and 3 months postoperatively (P < .05). No significant differences were found in DH and FH between the 2 groups preoperatively (P > .05); the OLIF group showed higher DH and FH than the PLIF group at all time points (P < .05). No significant differences were found in RI and LL between the 2 groups at any time point. All patients achieved fusion at 12 months postoperatively, and cage subsidence was not observed in either group.OLIF is effective and safe for the treatment of rostral ASD following prior posterior lumbar fusion, and is superior to PLIF in terms of perioperative parameters, short-term clinical outcomes, and DH restoration, with similar fusion and reduction rates.

Clinical and Radiologic Outcomes of Direct Versus Indirect Decompression with Lumbar Interbody Fusion: A Matched-Pair Comparison Analysis

To compare the radiologic and clinical outcomes between oblique lumbar interbody fusion (OLIF) without laminectomy and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF). This was a retrospective study. Between April 2012 and January 2017, 25 patients in each of the MI-TLIF and OLIF groups were recruited as matched pairs. Clinical outcomes included visual analogue scale, Oswestry Disability Index, and satisfaction rates. Radiographic outcomes comprised disc height (DH) and fusion status. Intraoperative data and complications were collected. All patients completed the clinical and radiologic outcomes. Outcomes were compared preoperatively and postoperatively. Matched pairs were compared between 2 groups in terms of demographic data and preoperative measurements; less blood loss and shorter operative time were found in OLIF versus MI-TLIF (P < 0.001). The total complication rate was 36% in OLIF and 32% in MI-TLIF (P= 0.77). The outcomes of visual analogue scale and Oswestry Disability Index were significantly improved in both groups, and there was no significant difference between 2 groups. Satisfaction rates of the both groups were more than 90%. OLIF was superior to MI-TLIF with respect its capability to restore DH (P < 0.001). Earlier time of fusion was observed in OLIF (80%) compared with MI-TLIF (52%) at 6 months (P= 0.04). OLIF may achieve equivalent clinical and radiologic outcomes compared with MI-TLIF when the stenosis is minimal because the decompression performed is indirect. Furthermore, the OLIF shows less blood loss and shorter operative time, better restoration of DH, and earlier time to fusion than the MI-TLIF.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters

BACKGROUND CONTEXT Lumbar fusion surgery can be performed through either anterior, lateral or posterior approaches. Although the relative advantage of anterior lumbar surgeries for the restoration of sagittal balance in spinal deformity is well-acknowledged, the comparative utility of these approaches in maintaining sagittal alignment following single level lumbar fusion remains unclear. PURPOSE A systematic review of the current literature was performed to assess the relative change in sagittal lumbar parameters including whole lumbar lordosis (WLL), segmental lumbar lordosis (SLL) and disc height (DH) following lumbar fusion using various approaches. STUDY DESIGN/SETTING Systematic review and meta-analysis. PATIENT SAMPLE All subjects in studies reporting imaging outcomes following single-level lumbar fusion, according to inclusion and exclusion criteria. OUTCOME MEASURES Lumbar sagittal parameters (SLL and WLL) and DH. METHODS A computerized literature search of all articles published up to April 17, 2017 was performed using PubMed and Cochrane databases. The following keywords were used: “anterior lumbar interbody fusion”, “ALIF”, “posterior lumbar interbody fusion”, “PLIF”, “trans-foraminal lumbar interbody fusion”, “TLIF”, “lumbar 360° fusion”, “circumferential lumbar fusion”, “combined anterior and posterior lumbar fusion”, “extreme lateral interbody fusion”, “LLIF”, “lateral lumbar interbody fusion”, “LLIF”, “direct lateral interbody fusion”, “DLIF”, “extraforaminal lumbar interbody fusion”, “ELIF”, with different combinations of operators including “AND”, “NOT” and “OR”. All studies were scored based on Methodological Index for NonRandomized Studies (MINORS) criteria. Pairwise comparisons of the fusion approach effect sizes were performed for the three imaging parameters. RESULTS A total of 1,563 articles under “ALIF”, 2,075 articles under “PLIF”, 1,032 articles under “TLIF”, 1,082 articles under “LLIF” and 894 under “circumferential lumbar fusion” were identified. The articles were further stratified on the basis of number of fusion levels. Only studies reporting relevant imaging outcomes following single-level fusion for degenerative pathologies were included in the final analysis. Using this strategy, a total of 14, 27, 25, 11 and 3 studies were included under ALIF, PLIF, TLIF, minimally invasive-TLIF and LLIF, respectively. Based on pairwise comparisons, ALIF significantly improved WLL and DH restoration as compared to all the other fusion modalities [ALIF vs. PLIF:2.5 (0.5–4.6) vs. 1.5 (0.2–2.4), p CONCLUSIONS Based on a systematic review of the literature, ALIF offers a significantly improved restoration of lumbar sagittal parameters following single-level lumbar fusion.

Transpsoas Lateral Lumbar Interbody Fusion for Degenerative Spine and Adult Deformity: Surgical Technique and the Evidence

The use of Lateral Lumbar Interbody Fusion (LLIF) initially applied for degenerative lumbar conditions, was expanded to the treatment of degenerative scoliosis as first reported by Phillips and Pimenta in 20051. Since then LLIF has been increasingly applied in the treatment of complex sagittal and coronal plane deformities. This approach can be performed “stand-alone” or in conjunction with posterior open or percutaneous pedicle screw placement. The lateral approach avoids the vascular risks of the anterior lumbar approach and the extensive soft tissue dissection and neural manipulation during a posterior approach. LLIF has been shown to be a safe, effective and low morbidity technique for achieving interbody fusion for a variety of lumbar conditions. LLIF has been shown to facilitate the restoration of disc height, sagittal balance and indirect decompression of neural elements. Injuries to the lumbar plexus have been described with this approach and risks can be reduced with use of real time neural surveillance as well as minimizing the duration of psoas retraction.

Adequate Restoration of Disc Height and Segmental Lordosis by Lumbar Interbody Fusion Decreases Adjacent Segment Degeneration

This study aimed to investigate the effects of lumbar interbody fusion-induced biomechanical changes on the adjacent segments, especially disc height and segmental lordosis restoration, and to provide more information for proper surgical strategy selection. The medical records of 528 patients who underwent posterior lumbar interbody fusion were retrospectively reviewed, and a total of 89 patients were included. Surgical indications included degenerative spondylolisthesis (nonspondylolytic), marked disc herniation, or lumbar spinal stenosis requiring extensive decompression at L4/5. Postoperative adjacent segment degeneration (ASD) was assessed based on X-rays and functional status. Disc height, foraminal height, segmental lordosis, lumbar lordosis, and cage geometry were compared between the ASD and non-ASD patients. To identify the possible risk factors for radiographic ASD, univariate analysis was performed first, followed by multivariate logistic regression using variables with P < 0.20. Univariate analysis revealed that the postoperative disc height in the non-ASD group were significantly greater than in the ASD group. The postoperative segmental lordosis in the non-ASD group was significantly greater than that in the ASD group, and the lumbar lordosis in the non-ASD group was also significantly greater than that in the ASD group at the final follow-up visit. Four variables were identified as independent risk factors for ASD by subsequent multivariate logistic regression: postoperative relative disc height of L4/5 (P= 0.011), postoperative segmental lordosis (P= 0.046), lumbar lordosis at the final follow-up visit (P=0.007), and cage height (P= 0.038). Improved lumbar lordosis is correlated with a lower incidence of ASD, and adequate disc height and segmental lordosis restoration are essential for ASD prevention.

Long-Term Minimum Clinically Important Difference in Health-Related Quality of Life Scores After Instrumented Lumbar Interbody Fusion for Low-Grade Isthmic Spondylolisthesis

Despite its growing popularity, no comparative studies have explored the minimum clinically important difference (MCID) of health-related quality of life scores following lumbar interbody fusion (LIF) performed on a single-level adult low-grade isthmic spondylolisthesis (LGIS). The purpose of this study is to investigate factors related to MCID of health-related quality of life scores following instrumented LIF performed on a single-level adult LGIS. Consecutive patients who underwent instrumented LIF for single-level LGIS were reviewed. The inclusion criteria were adult patients who underwent L4-5 or L5-S1, underwent anterior lumbar interbody fusion or transforaminal lumbar interbody fusion with a posterior screw fixation, and had a minimum 36-month postoperative follow-up period. MCID was defined as having an improved score of visual analog scale (VAS) back and leg pain >3 and Oswestry Disability Index (ODI) >12. Patients were subdivided into groups named "achievement" (A) and "nonachievement" (N) depending on their postoperative MCID for each health-related quality of life score category. One-hundred and five patients met the inclusion criteria. The overall achievement of MCID for VAS back, leg, and ODI was 80%, 73.3%, and 82.9%. MCID-VAS leg and ODI were less achieved at the L5-S1 level than at the L4-5 level. Postoperatively, disk height was higher and segmental lordosis (SL) was lower in group A of MCID-VAS leg. SL was lower in group A of MCID-ODI. We postulate that excessive SL does not affect lumbar lordosis; rather, it can result in lowering posterior disk height. The decrease in posterior DH may lead to a decreased foraminal height that, in turn, can lead to nerve root compression. Proper restoration of disk height and bone fusion is more important than restoration of more segmental lordosis or slip reduction for isthmic spondylolisthesis.

Complications on minimally invasive oblique lumbar interbody fusion at L2-L5 levels: a review of the literature and surgical strategies.

Fusion is the cornerstone in the treatment of an unstable degenerative lumbar spinal disease. Various techniques have been developed. Amongst these techniques exists the oblique lumbar interbody fusion (OLIF), which is the ante-psoas approach. Adequate restoration of disc height with large cages placed in the intervertebral space, indirect decompression, and correction of sagittal and coronal alignment can be achieved with OLIF procedure with the advantage of minimal risk for the psoas muscle and lumbar plexus. Nevertheless, this technique entails complications directly associated with the anatomical location where the fusion takes place. This surgical area is a window between the left lateral border of the aorta, or the left common iliac artery, and the anterior belly of the left psoas muscle. Vascular complications associated with the injury of the main vessels, segmental artery or iliolumbar vein of the lumbar spine have been reported, as well as urologic lesions due to ureter transgression, amongst others. Although these complications have been described in the literature, an article that complements this information with technical advice for its avoidance is yet to be published. This article is a review of the most frequent complications associated with the OLIF procedure in L2-L5 lumbar levels, as well as a description of technical strategies for the prevention of such complications.

ISSLS PRIZE IN BASIC SCIENCE 2018: Growth differentiation factor-6 attenuated pro-inflammatory molecular changes in the rabbit anular-puncture model and degenerated disc-induced pain generation in the rat xenograft radiculopathy model.

To elucidate the effects of growth differentiation factor-6 (GDF6) on: (i) gene expression of inflammatory/pain-related molecules and structural integrity in the rabbit intervertebral disc (IVD) degeneration model, and (ii) sensory dysfunction and changes in pain-marker expression in dorsal nerve ganglia (DRGs) in the rat xenograft radiculopathy model. Forty-six adolescent rabbits received anular-puncture in two non-consecutive lumbar IVDs. Four weeks later, phosphate-buffered saline (PBS) or GDF6 (1, 10 or 100µg) was injected into the nucleus pulposus (NP) of punctured discs and followed for 4weeks for gene expression analysis and 12weeks for structural analyses. For pain assessment, eight rabbits were sacrificed at 4weeks post-injection and NP tissues of injected discs were transplanted onto L5 DRGs of 16 nude rats to examine mechanical allodynia. The rat DRGs were analyzed immunohistochemically. In GDF6-treated rabbit NPs, gene expressions of interleukin-6, tumor necrosis factor-α, vascular endothelial growth factor, prostaglandin-endoperoxide synthase 2, and nerve growth factor were significantly lower than those in the PBS group. GDF6 injections resulted in partial restoration of disc height and improvement of MRI disc degeneration grades with statistical significance in rabbit structural analyses. Allodynia induced by xenograft transplantation of rabbit degenerated NPs onto rat DRGs was significantly reduced by GDF6 injection. Staining intensities for ionized calcium-binding adaptor molecule-1 and calcitonin gene-related peptide in rat DRGs of the GDF6 group were significantly lower than those of the PBS group. GDF6 injection may change the pathological status of degenerative discs and attenuate degenerated IVD-induced pain.

Adequate cage placement for a satisfactory outcome after lumbar lateral interbody fusion with MRI and CT analysis.

Introduction Through an extreme lateral retroperitoneal and transpsoas approach to intervertebral disc and fusion surgery, a large lordosis cage can be placed for solid and stable intervertebral fusion and to provide strong anterior support, disc height restoration, favorable alignment, and indirect nerve decompression. However, appropriate placement of the interbody cage remains insufficiently researched. We sought to determine both appropriate cage placement as well as other factors affecting nerve decompression in extreme lateral interbody fusion (XLIF) surgery. Methods We included 53 consecutive patients suffering from lumbar degenerative diseases with an indication for XLIF. Radiographic analysis using a sagittal computed tomography (CT) and axial magnetic resonance imaging (MRI) views was conducted to determine intervertebral disc height and angle, degree of disc bulging and thickness of the flavum, the area of the dural tube, cage height, pre- and postoperative disc bulging, change of disc bulging after surgery, cage subsidence, and cage placement at the rostral and caudal endplates. Results Intervertebral disc height and angle were significantly increased at all levels (L2/3, 3/4, 4/5) (p < 0.05). The area of the dural tube was significantly increased (p < 0.05), whereas the degree of disc bulging and thickness of the flavum were significantly decreased at all disc levels (p < 0.05). The enlarged area of the dural tube showed significant correlation with increased disc height (p = 0.019), preoperative flavum thickness (p = 0.008), change of flavum thickness (p < 0.0001), and cage placement at the rostral endplate (p = 0.014). Conclusions A decrease in flavum buckling is more important than disc protrusion as a consideration for obtaining indirect decompression. Central placement may be advantageous for indirect decompression.

Anterior Lumbar Interbody Fusion With Cement Augmentation Without Posterior Fixation to Treat Isthmic Spondylolisthesis in an Osteopenic Patient-A Surgical Technique.

Anterior lumbar interbody fusion (ALIF) has been well established as an effective surgical intervention for chronic back pain due to osteoporotic vertebral collapse. Historically, ALIF has consisted of an anterior approach to disc height restoration with a subsequent posterior pedicle screw fixation. Although the applications of cement augmentation with posterior fixation have been previously reported, treatment of patients with both isthmic spondylolisthesis and decreased bone mineral density using a stand-alone ALIF is controversial because of concerns for decreased fusion rates and increased subsidence risk, respectively. We report a case of stand-alone ALIF used to treat a low-grade isthmic spondylolisthesis in the setting of idiopathic thoraco-lumbar scoliosis in a patient with secondary degenerative changes and discuss the benefits of this surgical technique in a patient with several comorbidities. An osteopenic 66-year-old woman with multiple medical comorbidities and 2 years of left radicular leg pain was found to have a Myerding grade I isthmic spondylolisthesis in the setting of idiopathic thoraco-lumbar scoliosis with secondary changes. The patient underwent an L5-S1 stand-alone ALIF with anterior cement augmentation without posterior pedicle screw fixation. The patient experienced immediate relief of radicular leg pain postoperatively and had an uneventful course. At 2 years follow-up, she remained symptom free, and radiographs showed excellent fusion and maintenance of intervertebral disc height. The use of stand-alone ALIF with anterior cement augmentation of the vertebral bodies is a surgical technique that could produce excellent improvement in patients with low-grade isthmic spondylolisthesis in the setting of osteopenia. The use of the all-anterior approach in similar patients with multiple medical comorbidities can also be a useful technique, as it decreases associated morbidity of surgery and complication risks associated with prolonged operative times.

Osmosis and viscoelasticity both contribute to time-dependent behaviour of the intervertebral disc under compressive load: A caprine in vitro study

The mechanical behaviour of the intervertebral disc highly depends on the content and transport of interstitial fluid. It is unknown, however, to what extent the time-dependent behaviour can be attributed to osmosis. Here we investigate the effect of both mechanical and osmotic loading on water content, nucleus pressure and disc height. Eight goat intervertebral discs, immersed in physiological saline, were subjected to a compressive force with a pressure needle inserted in the nucleus. The loading protocol was: 10 N (6 h); 150 N (42 h); 10 N (24 h). Half-way the 150 N-phase (24 h), we eliminated the osmotic gradient by adding 26% poly-ethylene glycol to the surrounding fluid. For 62 additional discs, we determined the water content of both nucleus and annulus after 6, 24, 48, or 72 h. The compressive load was initially counterbalanced by the hydrostatic pressure in the nucleus. The load forced 4.3% of the water out of the nucleus, which reduced nucleus pressure by 44(±6)%. Reduction of the osmotic gradient disturbed the equilibrium disc height, and a significant loss of annulus water content was found. Remarkably, pressure and water content of the nucleus pulposus remained unchanged. This shows that annulus water content is important in the response to axial loading. After unloading, in the absence of an osmotic gradient, there was substantial viscoelastic recovery of 53(±11)% of the disc height, without a change in water content. However, for restoration of the nucleus pressure and for full restoration of disc height, restoration of the osmotic gradient was needed.

Circumferential fusion: a comparative analysis between anterior lumbar interbody fusion with posterior pedicle screw fixation and transforaminal lumbar interbody fusion for L5–S1 isthmic spondylolisthesis

Background ContextTransforaminal lumbar interbody fusion (TLIF) or anterior lumbar interbody fusion with percutaneous pedicle screws (ALIFPS) offer significantly higher radiographic fusion rates than other fusion techniques for L5–S1 isthmic spondylolisthesis (IS). As it stands, there is a relative paucity of comparative data of the two techniques. PurposeTo define the clinical, radiographic, and financial differences between TLIF and ALIFPS for L5–S1 IS. Design/SettingA retrospective cohort study conducted at a single tertiary care center. Patient SampleSixty-six patients who underwent either TLIF or ALIPFS for L5–S1 IS at a single tertiary care center between 2009 and 2014. Outcome MeasuresQuality of life outcome scores including the EuroQol-5 Dimensions (EQ-5D), Pain Disability Questionnaire (PDQ), and Patient Health Questionnaire-9 (PHQ-9). Sagittal balance parameters including: pelvic incidence, pelvic tilt, sacral slope, segmental lordosis, total lordosis, degree of slip, disc height, and L1-axis S1 distance (LASD). Cost measures included in-hospital charges, hospital length of stay (LOS), and post-admission costs accrued over 1 year. MethodsQuality of life (QoL) outcome scores, radiographic data, and financial data were collected with a minimum of 1-year follow-up. Clinical results were investigated using the PDQ, PHQ-9, and EQ-5D. Radiographic measurements included lumbar lordosis, segmental lordosis, pelvic tilt, pelvic incidence, height of disc, L-1 axis S-1 distance, and the degree of slip. Cost data were generated based on patient-level resource utilization. Comparative data were presented as median with interquartile range (IQR). Continuous variables were compared using either independent Student t tests assuming unequal variance or Mann-Whitney U tests for parametric and nonparametric variables, respectively. The minimally clinical important difference (MCID) used for each questionnaire was as follows: PDQ (26), PHQ-9 (5), and EQ-5D (0.4). ResultsA total of 66 patients met inclusion criteria. In the ALIFPS cohort, PDQ scores improved from 69 [47, 82] to 26 [18.2, 79.7], p=.02. In the TLIF cohort, PDQ scores improved from 73 [46, 85] to 48.5 [23, 67.5], p=.01. Both groups also showed a significant improvement in EQ-5D scores at 1 year, but the ALIFPS group showed a significantly greater improvement in EQ-5D scores at 1 year (0.1 [0,0.2] vs. 0.2 [0.1, 0.4], p=.02). Furthermore, only the ALIFPS cohort showed a significant improvement in segmental lordosis. The ALIFPS cohort showed a significantly greater improvement in disc height than did TLIF (3.5 [2, 5.5] vs. 6.7 [4.1, 10], p=.01). No significant differences were found in the direct costs of both procedures. ConclusionsOur findings suggest that anterior lumbar interbody fusion with percutaneous pedicle screws can achieve better clinical outcomes compared with TLIF for the treatment of IS. We believe the superior radiographic outcomes achieved through ALIFPS, namely a greater restoration of segmental lordosis and disc height, may have contributed to the improved clinical outcomes presented in the current study.

Does Lordotic Angle of Cage Determine Lumbar Lordosis in Lumbar Interbody Fusion?

Retrospective, radiological analysis. To determine that 15° lordotic angle cages create higher lumbar lordosis in open transforaminal lumbar interbody fusion (TLIF) than 4° and 8° cages. Restoration of lumbar lordosis is important to obtain good outcome after lumbar fusion surgery. Various shapes and angles of cages in interbody fusion have been used; however, it is not proved that lordotic angle of cages determine lumbar lordosis. Sixty-seven patients were evaluated after TLIF using 15° cages and screw instrumentation. For comparison, TLIF using 4° lordotic angle cages in 65 patients and 8° cages in 49 patients were analyzed. Lumbar lordosis angles, segmental lordosis angles, disc height, and bony union rate were measured on the radiographs. The lumbar lordosis was 31.1° preoperatively, improved to 42.9° postoperatively, and decreased to 36.4° at the last follow-up in the 15° group. It was 35.8° before surgery, corrected to 41.5° after surgery, and changed to 33.6° at the last follow-up in the 4° group. In the 8° group, it was 32.7° preoperatively, improved to 39.1° postoperatively, and decreased to 34.5° at the last follow-up. These changes showed statistical significances (P < 0.001). The segmental lordosis at L4-5 was 6.6° before surgery, 13.1° after surgery, and 9.8° at the last follow-up in the 15° group. It was 6.9°, 9.5°, and 6.2° in the 4° group and 6.7°, 9.8°, and 8.1° in the 8° group, respectively (P < 0.001). The disc height restoration was better in the 15° group than in the 4° and 8° groups (P < 0.001). Bony union rate was not significant among the three groups (P = 0.087). The lordotic angle of the cages determined restoration of lumbar lordosis after TLIF. Cages with sufficient lordotic angle showed better restoration of lumbar lordosis and prevention of loss of correction. 4.

Evaluating Outcomes of Stand-Alone Anterior Lumbar Interbody Fusion: A Systematic Review.

Stand-alone anterior lumbar interbody fusion (ALIF) is an effective surgical approach for selected spinal pathologies. It avoids the morbidity and complications associated with instrumented ALIF, such as plate fixation and the traditionally used posterior approach. Despite improved disc space visualization and clearance, the associated posterior instability and increased risk of nonfusion present major challenges to this approach. The integral cage design aims to address these challenges by providing the necessary stabilization through intracorporeal screws. However, there is limited and controversial data available for stand-alone ALIF and integral cage fixation. To our knowledge, this is the first systematic review to evaluate recent findings on outcomes of stand-alone ALIF devices to explore areas of controversy and identify directions for future research. Two reviewers conducted independent, systematic literature searches for appropriate studies in 5 electronic databases as per Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies were filtered by the use of specified selection criteria, particularly exclusion of studies with supplementary fixation to ALIF and studies published before the year 2000. A total of 17 studies met the criteria, and their data were comprehensively extracted and analyzed. The current literature is supportive of stand-alone ALIF due to acceptable clinical outcomes, promising fusion rates and disc height restoration. However, data and outcomes remain preliminary, and there are numerous areas of controversy. There is evidence for the efficacy and safety of stand-alone ALIF. However, the extent of improvement based on specific indications for surgery remains unclear. Further investigation utilizing more methodologically rigorous studies of long-term outcomes is necessary to address these issues.

Thermally triggered hydrogel injection into bovine intervertebral disc tissue explants induces differentiation of mesenchymal stem cells and restores mechanical function.

Low back pain (LBP) is associated with degeneration of the intervertebral disc (IVD). We have previously described development of a jelly delivery system (hydrogel). This has the potential to deliver adult stem cells to the centre of the IVD, known as the nucleus pulposus (NP). Here, we have demonstrated that adult stem cells can be safely injected into the NP using small bore needles, reducing damage to the disc. Following injection the hydrogel integrates with surrounding NP tissue, promotes differentiation of stem cells towards disc cells and restores IVD mechanical function. The hydrogel could be used to restore mechanical function to the IVD and deliver cells to promote regeneration of the disc as a minimally invasive treatment for LBP.

Change of Lumbar Ligamentum Flavum after Indirect Decompression Using Anterior Lumbar Interbody Fusion.

Study DesignRetrospective case series.PurposeThe purpose of this study was to examine changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a 10-year follow-up.Overview of LiteratureExtreme lateral interbody fusion provides minimally invasive treatment of the lumbar spine; this anterior fusion without direct posterior decompression, so-called indirect decompression, can achieve pain relief. Anterior fusion may restore disc height, stretch the flexure of the ligamentum flavum, and increase the spinal canal diameter. However, changes in the ligamentum flavum thickness and remodeling of the spinal canal after anterior fusion during a long follow-up have not yet been reported.MethodsWe evaluated 10 patients with L4 spondylolisthesis who underwent stand-alone anterior interbody fusion using the iliac crest bone. Magnetic resonance imaging was performed 10 years after surgery. The cross-sectional area (CSA) of the dural sac and the ligamentum flavum at L1–2 to L5–S1 was calculated using a Picture Archiving and Communication System.ResultsSpinal fusion with correction loss (average, 4.75 mm anterior slip) was achieved in all patients 10 years postsurgery. The average CSAs of the dural sac and the ligamentum flavum at L1–2 to L5–S1 were 150 mm2 and 78 mm2, respectively. The average CSA of the ligamentum flavum at L4–5 (30 mm2) (fusion level) was significantly less than that at L1–2 to L3–4 or L5–S1. Although patients had an average anterior slip of 4.75 mm, the average CSA of the dural sac at L4–5 was significantly larger than at the other levels.ConclusionsSpinal stability induced a lumbar ligamentum flavum change and a sustained remodeling of the spinal canal, which may explain the long-term pain relief after indirect decompression fusion surgery.

Efficacy of Platelet-Rich Plasma in Retarding Intervertebral Disc Degeneration: A Meta-Analysis of Animal Studies.

Objectives Several animal studies have demonstrated the positive effects of platelet-rich plasma (PRP) on disc degeneration retardation. The present meta-analysis was to verify the efficacy of PRP in retarding disc degeneration in animal. Methods Relevant studies were identified and evaluated according to our inclusion and exclusion criteria. The standardized mean difference (SMD) and related 95% confidence interval (95% CI) were estimated to assess PRP efficiency. Results In total, eleven studies were included in this meta-analysis. Significant differences were found in the PRP treatment group, which showed increased disc height (SMD = 2.66, 95% CI: 1.86, 3.47, p = 0.000), increased MRI T2 signal intensity (SMD = −3.29, 95% CI: −4.44, −2.13, p = 0.000), and decreased histological degeneration grade (SMD = −4.28, 95% CI: −5.26, −3.30, p = 0.000). However, no significant increase in collagen II expression was found (SMD = 25389.74, 95% CI: −27585.72, 78365.21, p = 0.348). Apart from the subgroup analysis of the disc height based on animal species (pig) and disc degeneration model (chymopapain induction), other subgroup analysis based on animal species (rabbit and rat), study design, disc degeneration model, and follow-up period demonstrated that PRP treatment can significantly restore disc height and increase MRI T2 signal intensity. Conclusions PRP treatment is potentially effective in restoring disc height of rodent rabbit and rat, reducing histological degeneration grade, and increasing MRI T2 image signal. PRP injection may be promising therapy for retarding disc degeneration.

Is the Cage an Additional Hardware in Lumbar Interbody Fusion for Low Grade Spondylolisthesis? A Prospective Study

Lumbar interbody fusion has become the standard of care for the management of lumbar instability, where fusion is achieved using bone grafts, cages, etc. The aim of the study was to compare the outcomes of the interbody fusion using interbody cage technique and stand alone local bone graft technique. A total of 30 patients, operated for single level instability with low grade lytic and degenerative spondylolisthesis of L4-5/L5-S1, were selected and grouped into two groups: Group I (stand alone grafts) and Group II (interbody cage and graft) based on computer generated random numbers. All patients who underwent interbody fusion through conventional open posterior approach were included in the study. Data regarding the time taken for interbody fusion, formaninal height maintenance, disc height restoration, translation, functional scores (VAS,ODI) and operative complications were analysed using in both the groups was collected and a student's-t test was performed to evaluate the difference. The mean age of patients in Group I was 46.7 years whereas, the mean age of patients in Group II was 43.5 years with mean age of 46.7 years and 43.5 years respectively. Interbody fusion, was achieved in seven and eight months in Group I and II respectively (p>0.05). The clinical results of both groups were comparable and there was no significant difference between the two groups in VAS score (p-0.147) and ODI score (p-0.983). Radiological parameters were also comparable and there was no significant difference between the postoperative measurements of the two groups (p=0.348 for translation, p=0.310 for intervertebral disc height and p=0.135 for foraminal height). One patient in Group I had transient foot drop which recovered, while one in Group II had infection, wound was managed with wound wash and antibiotics and another patient in Group II had pseudoarthrosis. Lumbar interbody fusion with standalone local bone grafts is sufficient in single level low grade spondylolisthesis treated by conventional open surgery.

Effect of a titanium cage as a stand-alone device on biomechanical stability in the lumbosacral spine of canine cadavers

Degenerative lumbosacral stenosis is a common disease in dogs characterised by intervertebral disc herniation, loss of disc height and stenosis. Decompressive dorsal laminectomy and partial discectomy can cause spinal instability and worsen foraminal stenosis. Pedicle screw and rod fixation (PSRF) with an intervertebral body cage allows for distraction and restoration of disc height and restores foraminal apertures. The aim of this study was to evaluate the ex vivo biomechanical properties of a titanium intervertebral cage alone and in combination with PSRF in the lumbosacral spine of dogs. The range of motion, neutral zone, neutral zone stiffness and elastic zone stiffness of the lumbosacral joint (L7-S1) of nine canine cadavers were determined in flexion/extension, lateral bending and axial rotation for four conditions: (1) native (unmodified) spine; (2) dorsal laminectomy and discectomy; (3) stand-alone cage; and (4) cage in combination with PSRF. The intervertebral disc height decreased after dorsal laminectomy, but increased after insertion of the cage. Insertion of the stand-alone cage decreased the range of motion and neutral zone compared to the laminectomy-discectomy and increased neutral zone stiffness in all directions. The range of motion further decreased after PSRF. From a biomechanical point of view, the use of a stand-alone intervertebral cage is a potential alternative to dorsal fixation of the lumbosacral junction, since it increases spinal stability and restores disc height.