Resolvin D3 Promotes Inflammatory Resolution, Neuroprotection, and Functional Recovery After Spinal Cord Injury.

Resolvins, a new family from the endogenous specialized pro-resolving mediators (SPMs), promote the resolution of the inflammatory response. Resolvin D3 (RvD3), a docosahexaenoic acid (DHA) product, has been known to suppress the inflammatory response. However, the anti-inflammatory and neuroprotective effects of RvD3 are not known in a model of spinal cord injury (SCI). Here, we investigated the anti-inflammatory and neuroprotective effect of RvD3 in a mouse model of SCI. Processes associated with anti-inflammation and angiogenesis were studied in RAW 264.7 cells and the human brain endothelial cell line hCMEC/D3, respectively. Additionally, female C57BL/6 mice were subjected to moderate compression SCI (20-g weight compression for 1 min) followed by intrathecal injection of vehicle or RvD3 (1 µg/20 µL) at 1 h post-SCI. RvD3 decreased the lipopolysaccharide (LPS)-induced production of inflammatory mediators and nitric oxide (NO) in RAW 264.7 cells and promoted an angiogenic effect in the hCMEC/D3 cell line. Treatment with RvD3 improved locomotor recovery and reduced thermal hyperalgesia in SCI mice compared with vehicle treatment at 14 days post-SCI. Remarkably, RvD3-treated mice exhibited reduced expression of inflammatory cytokines (TNF-α, IL6, IL1ß) and chemokines (CCL2, CCL3). Also, RvD3-treated mice exhibited increased expression of tight junction proteins such as zonula occludens (ZO)-1 and occludin. Furthermore, immunohistochemistry showed a decreased level of gliosis (GFAP, Iba-1) and neuroinflammation (CD68, TGF-ß) and enhanced neuroprotection. These data provide evidence that intrathecal injection of RvD3 represents a promising therapeutic strategy to promote inflammatory resolution, neuroprotection, and neurological functional recovery following SCI.

Safety and efficacy of Wharton's jelly-derived mesenchymal stem cells with teriparatide for osteoporotic vertebral fractures: A phase I/IIa study.

Osteoporotic vertebral compression fractures (OVCFs) are serious health problems. We conducted a randomized, open-label, phase I/IIa study to determine the feasibility, safety, and effectiveness of Wharton's jelly-derived mesenchymal stem cells (WJ-MSCs) and teriparatide (parathyroid hormone 1-34) in OVCFs. Twenty subjects with recent OVCFs were randomized to teriparatide (20 µg/day, daily subcutaneous injection for 6 months) treatment alone or combined treatment of WJ-MSCs (intramedullary [4 × 107 cells] injection and intravenous [2 × 108 cells] injection after 1 week) and teriparatide (20 µg/day, daily subcutaneous injection for 6 months). Fourteen subjects (teriparatide alone, n = 7; combined treatment, n = 7) completed follow-up assessment (visual analog scale [VAS], Oswestry Disability Index [ODI], Short Form-36 [SF-36], bone mineral density [BMD], bone turnover measured by osteocalcin and C-terminal telopeptide of type 1 collagen, dual-energy x-ray absorptiometry [DXA], computed tomography [CT]). Our results show that (a) combined treatment with WJ-MSCs and teriparatide is feasible and tolerable for the patients with OVCFs; (b) the mean VAS, ODI, and SF-36 scores significantly improved in the combined treatment group; (c) the level of bone turnover markers were not significantly different between the two groups; (d) BMD T-scores of spine and hip by DXA increased in both control and experimental groups without a statistical difference; and (e) baseline spine CT images and follow-up CT images at 6 and 12 months showed better microarchitecture in the combined treatment group. Our results indicate that combined treatment of WJ-MSCs and teriparatide is feasible and tolerable and has a clinical benefit for fracture healing by promoting bone architecture. Clinical trial registration: https://nedrug.mfds.go.kr/, MFDS: 201600282-30937.

Magnesium hydroxide-incorporated PLGA composite attenuates inflammation and promotes BMP2-induced bone formation in spinal fusion.

Spinal fusion has become a common surgical technique to join two or more vertebrae to stabilize a damaged spine; however, the rate of pseudarthrosis (failure of fusion) is still high. To minimize pseudarthrosis, bone morphogenetic protein-2 (BMP2) has been approved for use in humans. In this study, we developed a poly(lactide-co-glycolide) (PLGA) composite incorporated with magnesium hydroxide (MH) nanoparticles for the delivery of BMP2. This study aimed to evaluate the effects of released BMP2 from BMP2-immobilized PLGA/MH composite scaffold in an in vitro test and an in vivo mice spinal fusion model. The PLGA/MH composite films were fabricated via solvent casting technique. The surface of the PLGA/MH composite scaffold was modified with polydopamine (PDA) to effectively immobilize BMP2 on the PLGA/MH composite scaffold. Analyzes of the scaffold revealed that using PLGA/MH-PDA improved hydrophilicity, degradation performance, neutralization effects, and increased BMP2 loading efficiency. In addition, releasing BMP2 from the PLGA/MH scaffold significantly promoted the proliferation and osteogenic differentiation of MC3T3-E1 cells. Furthermore, the pH neutralization effect significantly increased in MC3T3-E1 cells cultured on the BMP2-immobilized PLGA/MH scaffold. In our animal study, the PLGA/MH scaffold as a BMP2 carrier attenuates inflammatory responses and promotes BMP2-induced bone formation in posterolateral spinal fusion model. These results collectively demonstrate that the BMP2-immobilized PLGA/MH scaffold offers great potential in effectively inducing bone formation in spinal fusion surgery.

An Injectable Hyaluronan-Methylcellulose (HAMC) Hydrogel Combined with Wharton's Jelly-Derived Mesenchymal Stromal Cells (WJ-MSCs) Promotes Degenerative Disc Repair.

Intervertebral disc (IVD) degeneration is one of the predominant causes of chronic low back pain (LBP), which is a leading cause of disability worldwide. Despite substantial progress in cell therapy for the treatment of IVD degeneration, significant challenges remain for clinical application. Here, we investigated the effectiveness of hyaluronan-methylcellulose (HAMC) hydrogels loaded with Wharton's Jelly-derived mesenchymal stromal cell (WJ-MSCs) in vitro and in a rat coccygeal IVD degeneration model. Following induction of injury-induced IVD degeneration, female Sprague-Dawley rats were randomized into four groups to undergo a single intradiscal injection of the following: (1) phosphate buffered saline (PBS) vehicle, (2) HAMC, (3) WJ-MSCs (2 × 104 cells), and (4) WJ-MSCs-loaded HAMC (WJ-MSCs/HAMC) (n = 10/each group). Coccygeal discs were removed following sacrifice 6 weeks after implantation for radiologic and histologic analysis. We confirmed previous findings that encapsulation in HAMC increases the viability of WJ-MSCs for disc repair. The HAMC gel maintained significant cell viability in vitro. In addition, combined implantation of WJ-MSCs and HAMC significantly promoted degenerative disc repair compared to WJ-MSCs alone, presumably by improving nucleus pulposus cells viability and decreasing extracellular matrix degradation. Our results suggest that WJ-MSCs-loaded HAMC promotes IVD repair more effectively than cell injection alone and supports the potential clinical use of HAMC for cell delivery to arrest IVD degeneration or to promote IVD regeneration.

Safety and Tolerability of Stromal Vascular Fraction Combined with ß-Tricalcium Phosphate in Posterior Lumbar Interbody Fusion: Phase I Clinical Trial.

The rates of pseudarthrosis remain high despite recent advances in bone graft substitutes for spinal fusion surgery. The aim of this single center, non-randomized, open-label clinical trial was to determine the feasibility of combined use of stromal vascular fraction (SVF) and ß-tricalcium phosphate (ß-TCP) for patients who require posterior lumbar interbody fusion (PLIF) and pedicle screw fixation. Two polyetheretherketone (PEEK) cages were inserted into the intervertebral space following complete removal of the intervertebral disc. The PEEK cage (SVF group) on the right side of the patient was filled with ß-TCP in combination with SVF, and the cage on the left side (control group) was filled with ß-TCP alone. Fusion rate and cage subsidence were assessed by lumbar spine X-ray and CT at 6 and 12 months postoperatively. At the 6-month follow-up, 54.5% of the SVF group (right-sided cages) and 18.2% of the control group (left-sided cages) had radiologic evidence of bone fusion (p = 0.151). The 12-month fusion rate of the right-sided cages was 100%, while that of the left-sided cages was 91.6% (p = 0.755). Cage subsidence was not observed. Perioperative combined use of SVF with ß-TCP is feasible and safe in patients who require spinal fusion surgery, and it has the potential to increase the early bone fusion rate following spinal fusion surgery.

Combined Treatment with Fasudil and Menthol Improves Functional Recovery in Rat Spinal Cord Injury Model.

Neuroprotective measures by preventing secondary spinal cord injury (SCI) are one of the main strategies for repairing an injured spinal cord. Fasudil and menthol may be potent neuroprotective agents, which act by inhibiting a rho-associated protein kinase (ROCK) and suppressing the inflammatory response, respectively. We hypothesized that combined treatment of fasudil and menthol could improve functional recovery by decreasing inflammation, apoptosis, and glial scar formation. We tested our hypothesis by administering fasudil and menthol intraperitoneally (i.p.) to female Sprague Dawley rats after moderate static compression (35 g of impounder for 5 min) of T10 spinal cord. The rats were randomly divided into five experimental groups: (i) sham animals received laminectomy alone, (ii) injured (SCI) and untreated (saline 0.2 mL/day, i.p.) rats, (iii) injured (SCI) rats treated with fasudil (10 mg/kg/day, i.p.) for two weeks, (iv) injured (SCI) rats treated with menthol (10 mg/kg/day, i.p.) for twoweeks, (v) injured (SCI) rats treated with fasudil (5 mg/kg/day, i.p.) and menthol (10 mg/kg/day, i.p.) for two weeks. Compared to single treatment groups, combined treatment of fasudil and menthol demonstrated significant functional recovery and pain amelioration, which, thereby, significantly reduced inflammation, apoptosis, and glial/fibrotic scar formation. Therefore, combined treatment of fasudil and menthol may provide effective amelioration of spinal cord dysfunction by a synergistic effect of fasudil and menthol.

Efficacy of matrilin-3-primed adipose-derived mesenchymal stem cell spheroids in a rabbit model of disc degeneration.

BACKGROUND: Chronic low back pain is a prevalent disability, often caused by intervertebral disc (IVD) degeneration. Mesenchymal stem cell (MSC) therapy could be a safe and feasible option for repairing the degenerated disc. However, for successful translation to the clinic, various challenges need to be overcome including unwanted adverse effects due to acidic pH, hypoxia, and limited nutrition. Matrilin-3 is an essential extracellular matrix (ECM) component during cartilage development and ossification and exerts chondrocyte protective effects. METHODS: This study evaluated the effects of matrilin-3-primed adipose-derived MSCs (Ad-MSCs) on the repair of the degenerated disc in vitro and in vivo. We determined the optimal priming concentration and duration and developed an optimal protocol for Ad-MSC spheroid generation. RESULTS: Priming with 10 ng/ml matrilin-3 for 5 days resulted in the highest mRNA expression of type 2 collagen and aggrecan in vitro. Furthermore, Ad-MSC spheroids with a density of 250 cells/microwell showed the increased secretion of favorable growth factors such as transforming growth factor beta (TGF-ß1), TGF-ß2, interleukin-10 (IL-10), granulocyte colony-stimulating factor (G-CSF), and matrix metalloproteinase 1 (MMP1) and decreased secretion of hypertrophic ECM components. In addition, matrilin-3-primed Ad-MSC spheroid implantation was associated with optimal repair in a rabbit model. CONCLUSION: Our results suggest that priming MSCs with matrilin-3 and spheroid formation could be an effective strategy to overcome the challenges associated with the use of MSCs for the treatment of IVD degeneration.

Therapeutic Potential of Tauroursodeoxycholic Acid for the Treatment of Osteoporosis.

Tauroursodeoxycholic acid (TUDCA) is a US FDA-approved hydrophilic bile acid for the treatment of chronic cholestatic liver disease. In the present study, we investigate the effects of TUDCA on the proliferation and differentiation of osteoblasts and its therapeutic effect on a mice model of osteoporosis. Following treatment with different concentrations of TUDCA, cell viability, differentiation, and mineralization were measured. Three-month-old female C57BL/6 mice were randomly divided into three groups (n = 8 mice per group): (i) normal mice as the control group, (ii) ovariectomy (OVX) group (receiving phosphate-buffered saline (PBS) treatment every other day for 4 weeks), and (iii) OVX group with TUDCA (receiving TUDCA treatment every other day for 4 weeks starting 6 weeks after OVX). At 11 weeks post-surgery, serum levels of procollagen type I N-terminal propeptides (PINP) and type I collagen crosslinked C-telopeptides (CTX) were measured, and all mice were sacrificed to examine the distal femur by micro-computed tomography (CT) scans and histology. TUDCA (100 nM, 1 µM) significantly increased the proliferation and viability of osteoblasts and osteoblast differentiation and mineralization when used in vitro. Furthermore, TUDCA neutralized the detrimental effects of methylprednisolone (methylprednisolone-induced osteoblast apoptosis). In the TUDCA treatment group the PINP level was higher and the CTX level was lower, but these levels were not significantly different compared to the PBS treatment group. Micro-CT and histology showed that the TUDCA treatment group preserved more trabecular structures in the distal femur compared to the PBS treatment group. In addition, the TUDCA treatment group increased the percentage bone volume with respect to the total bone volume, bone mineral density, and mice distal femur trabeculae compared with the PBS treatment group. Taken together, our findings suggest that TUDCA may provide a favorable effect on bones and could be used for the prevention and treatment of osteoporosis.

3'-UTR Polymorphisms of Vitamin B-Related Genes Are Associated with Osteoporosis and Osteoporotic Vertebral Compression Fractures (OVCFs) in Postmenopausal Women.

As life expectancy increases, the prevalence of osteoporosis is increasing. In addition to vitamin D which is well established to have an association with osteoporosis, B vitamins, such as thiamine, folate (vitamin B9), and cobalamin (vitamin B12), could affect bone metabolism, bone quality, and fracture risk in humans by influencing homocysteine/folate metabolism. Despite the crucial role of B vitamins in bone metabolism, there are few studies regarding associations between B vitamin-related genes and osteoporosis. In this study, we investigated the genetic association of four single nucleotide polymorphisms (SNPs) within the 3'-untranslated regions of vitamin B-related genes, including TCN2 (encodes transcobalamin II), CD320 (encodes transcobalamin II receptor), SLC19A1 (encodes reduced folate carrier protein 1), and SLC19A2 (encodes thiamine carrier 1), with osteoporosis and osteoporotic vertebral compression fracture (OVCF). We recruited 301 postmenopausal women and performed genotyping of CD320 rs9426C>T,TCN2 rs10418C>T, SLC19A1 rs1051296G>T, and SLC19A2 rs16862199C>T using a polymerization chain reaction-restriction fragment length polymorphism assay. There was a significantly higher incidence of both osteoporosis (AOR 5.019; 95% CI, 1.533-16.430, p < 0.05) and OVCF (AOR, 5.760; 95% CI, 1.480-22.417, p < 0.05) in individuals with genotype CD320 CT+TT and high homocysteine concentrations. Allele combination analysis revealed that two combinations, namely CD320 C-TCN2 T-SLC19A1 T-SLC19A2 C (OR, 3.244; 95% CI, 1.478-7.120, p < 0.05) and CD320 T-TCN2 C-SLC19A1 G-SLC19A2 C (OR, 2.287; 95% CI, 1.094-4.782, p < 0.05), were significantly more frequent among the osteoporosis group. Our findings suggest that SNPs within the CD320 gene in 3´-UTR may contribute to osteoporosis and OVCF occurrences in some individuals. Furthermore, specific allele combinations of CD320, TCN2, SLC19A1, and SLC19A2 may contribute to increased susceptibility to osteoporosis and OVCF.

Correction: "Changes in the medical burden of pyogenic and tuberculous spondylitis between 2007 and 2016: A nationwide cohort study".

BACKGROUND: This nationwide study aimed to compare the medical burdens of pyogenic spondylitis (PS) and tuberculous spondylitis (TS) between 2007 and 2016 in Korea. METHODS: We used a national database managed by the National Health Insurance Service (NHIS) with data from the years 2007 and 2016. A total of 9655 newly diagnosed patients with PS or TS were correspondingly enrolled in the PS or TS group. Chi square test analyses were used to compare the PS and TS groups. RESULTS: The overall incidence of infectious spondylitis during the study period was 9655 persons. The PS and TS groups consisted of 7305 and 2350 cases, respectively. Individual medical costs in the PS group (USD 10,049 ± 94 vs. USD 16,672 ± 17,729, P < 0.001) and the TS group (USD 4882 ± 6869 vs. USD 8531 ± 10,709, P < 0.001) both increased. The total medical cost for the PS group increased significantly between 2007 and 2016 in Korea (USD 24,428,560 vs. USD 81,044,196, P < 0.001). In contrast, the total medical cost for the TS group decreased between 2007 and 2016 in Korea (USD 8,573,038 vs. USD 4,879,520, P < 0.001). CONCLUSION: This nationwide study shows that the total medical cost of PS has increased and that the total medical cost of TS has decreased between 2007 and 2016 in Korea.

CORM-2-Solid Lipid Nanoparticles Maintain Integrity of Blood-Spinal Cord Barrier After Spinal Cord Injury in Rats.

Spinal cord injury (SCI) is a devastating condition of the central nervous system that can lead to permanent motor and sensory deficits. Carbon monoxide-releasing molecule-2 (CORM-2) has been shown to have anti-inflammatory, anti-apoptotic, and angiogenic properties that may be useful for the treatment of SCI. However, it has a short carbon monoxide (CO) release half-life (approximately 1 min). To address this challenge, we developed a CORM-2-incorporated solid lipid nanoparticle (CORM-2-SLN) and evaluated its ameliorating effects for preventing blood-spinal cord barrier (BSCB) disruption and endothelial cell death following SCI. After a moderate compression injury of the spinal cord (compression with a 35-g impounder for 5 min), groups of rats were treated with a CORM-2-solution and CORM-2-SLNs at an equal dose of 10 mg/kg each via an intraperitoneal injection for 8 consecutive days. Behavior analysis was performed and animals were later sacrificed at different time points and evaluated for whether the CORM-2-SLNs prevented BSCB disruption and rescued endothelial cell damage following SCI. The CORM-2-SLN-treated group showed significantly diminished extravasation of Evans Blue dye with enhanced expression of tight junction proteins following SCI. Likewise, significantly diminished endothelial cell markers after SCI were optimally stabilized at 21 days. Additionally, lipopolysaccharide (LPS)-induced loss of tight junction integrity was significantly preserved after CORM-2-SLN treatment in human cerebral microvascular endothelial cell line (hCMEC/D3). Clinically, CORM-2-SLNs were associated with a significantly improved functional recovery, as compared with the CORM-2-solution. CORM-2-SLNs may help potentially to maintain BSCB integrity following SCI.

Risk of rod fracture according to cross-link position in pedicle subtraction osteotomy (PSO): A finite element study.

PURPOSE: The purpose of this study is to investigate the effect of the cross-link position on the rod fracture phenomenon during pedicle subtraction osteotomy (PSO) surgery using finite element model (FEM). METHODS: A three-dimensional finite element model of a lumbar spine with sagittal imbalance was constructed using computed tomography data of a 65-year-old female patient. After simulating the standard PSO at the L4 level, we constructed four models, specifically a model without a cross-link and three models with a cross-link at three different sites. The peak von Mises stress (PVMS) of the rod around the PSO site was measured after applying physiological loads (flexion, extension, axial rotation, and lateral bending) in each model. RESULTS: The measured PVMS outcomes at the PSO site were 135.8, 135.9, 208.9, and 384.7 MPa for model 1, 2, 3, and 4 during flexion, and 180.0, 180.1, 210.1, and 445.7 MPa during extension. These results show that when the cross-link is located at the PSO site, the rod stress at the PSO site increases significantly during flexion and extension. As the cross-link moved away from the PSO site, the effect on the rod stress decreased. When the cross-link was placed two levels away from the PSO site, the rod stress was scarcely affected. CONCLUSION: When the cross-link during PSO surgery was positioned two levels away from the PSO site, the risk of rod fracture did not increase.

Changes in the medical burden of pyogenic and tuberculous spondylitis between 2007 and 2016: A nationwide cohort study.

BACKGROUND: This nationwide study aimed to compare the medical burdens of pyogenic spondylitis (PS) and tuberculous spondylitis (TS) between 2007 and 2016 in Korea. METHODS: We used a national database managed by the National Health Insurance Service (NHIS) with data from the years 2007 and 2016. A total of 9655 newly diagnosed patients with PS or TS were correspondingly enrolled in the PS or TS group. Chi square test analyses were used to compare the PS and TS groups. RESULTS: The overall incidence of infectious spondylitis during the study period was 9655 persons. The PS and TS groups consisted of 7305 and 2350 cases, respectively. Individual medical costs in the PS group (USD 10,049 ± 94 vs. USD 16,672 ± 17,729, P < 0.001) and the TS group (USD 4882 ± 6869 vs. USD 8531 ± 10,709, P < 0.001) both increased. The total medical cost for the PS group increased significantly between 2007 and 2016 in Korea (USD 24,428,560 vs. USD 81,044,196, P < 0.001). In contrast, the total medical cost for the TS group decreased between 2007 and 2016 in Korea (USD 8,573,038 vs. USD 4,879,520, P < 0.001). CONCLUSION: This nationwide study shows that the total medical cost of PS has increased and that the total medical cost of TS has decreased between 2007 and 2016 in Korea.

Symptomatic posterior fossa and supratentorial subdural hygromas as a rare complication following transarticular screw fixation with posterior wiring for atlantoaxial instability: A case report.

RATIONALE: Atlantoaxial transarticular screw fixation has been an effective and appealing method for inducing fusion of the C1-C2 complex. This technique is usually performed with Gallie fusion. In performing Gallie fusion using sublaminar wiring, a major concern is the risk of dural tear associated with passing sublaminar wires through the epidural space. We present the first report on symptomatic symptomatic subdural hygroma (SDH) due to transarticular screw fixation with posterior wiring. PATIENTS CONCERNS: A 50-year-old man had sustained dens fracture 20 years ago and presented with severe neck pain following a recent traffic accident. The images showed atlantoaxial instability due to nonunion of the dens fracture and the patient underwent transarticular screw fixation with posterior sublaminar wiring using Gallie technique. When the U-shaped wire was passed under the arch of C1 from inferior to superior, a dural tear and cerebrospinal fluid (CSF) leak occurred. The site of dural tear was repaired by direct application of sutures. The patient was discharged in good condition. Fifteen day after surgery, the patient was readmitted with a history of a progressive headache associated with vomiting and vertigo. DIAGNONSIS: Brain CT and MRI showed bilateral posterior fossa and a right-sided supratentorial SDH. INTERVENTIONS: The patient underwent right occipital burr hole and evacuation of posterior fossa SDH due to deteriorating neurological status. OUTCOMES: The patient's condition gradually improved after the operation and became asymptomatic at 3-year follow-up. LESSONS: Posterior fossa and supratentorial SDH could occur resulting from any intraoperative dural tear and CSF leakage during posterior cervical spinal surgery. Symptomatic SDH after posterior cervical spinal surgery should be cautiously assessed and treated. LEVEL OF EVIDENCE: 5.

Residence could influence the surgical outcome after corrective surgery in adult spinal deformity: comparison study between urban and rural area in Korea.

PURPOSE: Numerous factors affect the surgical outcomes in patients with adult spinal deformity (ASD). However, no study has examined the relationship between residence and physical factors and surgical outcomes in patients with ASD. Here, we analysed the impact of residence and physical factors on the post-operative outcomes of patients with ASD residing in urban (U) and rural (R) environments. METHODS: We retrospectively reviewed data from patients who had undergone ASD surgery with sacropelvic fixation at a single institution between June 2011 and May 2017 with a minimum 1 year follow-up. We divided the patients into two groups (U and R). Preoperative demographic data were reviewed, and radiographic parameters were measured preoperatively, immediately postoperatively, at 1, 3, and 6 months, and at the final follow-up. The L4 axial paraspinal muscles were measured preoperatively using magnetic resonance imaging. RESULTS: There were 25 and 34 patients in the U and R groups, respectively. Both groups had similar preoperative demographic and radiological parameters. There were no differences between the groups in post-operative radiographic parameters, clinical outcomes, and complications, but proximal junctional kyphosis (PJK) was significantly higher in the R group. Additionally, muscle mass in the multifidus and erector spinae was lower in the R than in the U group. CONCLUSIONS: Patient residence influenced PJK in patients with ASD. Mass reduction in the trunk extensor muscle is an important and existing risk factor for PJK. Surgeons should be aware of this information for preoperative counselling, informed consent, and post-operative education of patients with ASD. These slides can be retrieved from Electronic Supplementary Material.

Unilateral versus bilateral percutaneous pedicle screw fixation in minimally invasive transforaminal lumbar interbody fusion.

OBJECT: Clinical results for unilateral pedicle screw fixation after lumbar interbody fusion have been reported to be as good as those for bilateral instrumentation. However, no studies have directly compared unilateral and bilateral percutaneous pedicle screw fixation after minimally invasive surgery (MIS) for transforaminal lumbar interbody fusion (TLIF). The purpose of this study was to determine whether unilateral percutaneous pedicle screw fixation is comparable with bilateral percutaneous pedicle screw fixation in 1-segment MIS TLIF. METHODS: This was a prospective randomized study of 53 patients who underwent unilateral or bilateral percutaneous pedicle screw fixation after MIS TLIF for 1-segment lumbar degenerative disc disease. Twenty-six patients were assigned to a unilateral percutaneous pedicle screw fixation group and 27 patients were assigned to a bilateral percutaneous pedicle screw fixation group. Operative time, blood loss, clinical outcomes (that is, Oswestry Disability Index [ODI] and visual analog scale [VAS] scores), complication rates, and fusion rates were assessed using CT scanning 2 years after surgical treatment. RESULTS: The 2 groups were similar in age, sex, preoperative diagnosis, and operated level, and they did not differ significantly in the length of follow-up (27.5 [Group 1] vs 28.9 [Group 2] months) or clinical results. Both groups showed substantial improvements in VAS and ODI scores 2 years after surgical treatment. The groups differed significantly in operative time (unilateral 84.2 minutes; bilateral 137.6 minutes), blood loss (unilateral 92.7 ml; bilateral, 232.0 ml), fusion rate (unilateral 84.6%; bilateral 96.3%), and postoperative scoliotic change (unilateral 23.1%; bilateral 3.7%). CONCLUSIONS: Unilateral and bilateral screw fixation after MIS TLIF produced similar clinical results. Although perioperative results were better with unilateral screw fixation, the long-term results were better with bilateral screw fixation, suggesting bilateral screw fixation is a better choice after MIS TLIF.