Predictive Classification System for Low Back Pain Based on Unsupervised Clustering.

STUDY DESIGN: Retrospective study. OBJECTIVE: Lumbar magnetic resonance imaging (MRI) findings are believed to be associated with low back pain (LBP). This study sought to develop a new predictive classification system for low back pain. METHOD: Normal subjects with repeated lumbar MRI scans were retrospectively enrolled. A new classification system, based on the radiological features on MRI, was developed using an unsupervised clustering method. RESULTS: One hundred and fifty-nine subjects were included. Three distinguishable clusters were identified with unsupervised clustering that were significantly correlated with LBP (P = .017). The incidence of LBP was highest in cluster 3 (57.14%), nearly twice the incidence in cluster 1 (30.11%). There were obvious differences in the sagittal parameters among the 3 clusters. Cluster 3 had the smallest intervertebral height. Based on follow-up findings, 27% of subjects changed clusters. More subjects changed from cluster 1 to clusters 2 or 3 (14.5%) than changed from cluster 2 or cluster 3 to cluster 1 (5%). Participation in sport was more frequent in subjects who changed from cluster 3 to cluster 1. CONCLUSION: Using an unsupervised clustering method, we developed a new classification system comprising 3 clusters, which were significantly correlated with LBP. The prediction of LBP is independent of age and better than that based on individual sagittal parameters derived from MRI. A change in cluster during follow-up may partially predict lumbar degeneration. This study provides a new system for the prediction of LBP that should be useful for its diagnosis and treatment.

In vitro and in vivo effects of hyperglycemia and diabetes mellitus on nucleus pulposus cell senescence.

Diabetes mellitus contributes to intervertebral disc degeneration. Nucleus pulposus cell senescence plays an important role in intervertebral disc degeneration. However, the effects of hyperglycemia on human nucleus pulposus cells and the underlying process remains poorly understood. In the current study, we evaluated the effects of high glucose levels on human nucleus pulposus cell senescence in vitro and the effects of hyperglycemia on rat nucleus pulposus aging in vivo. Human nucleus pulposus cells were cultured in high-glucose medium (200 mM glucose) for 48 h. Senescence-associated ß-galactosidase staining, western blot analysis, and enzyme-linked immunosorbent assays were performed to evaluate human nucleus pulposus cell senescence. Flow cytometry and enzyme-linked immunosorbent assays were used to evaluate reactive oxygen species and advanced glycation end-product levels. Transcriptome sequencing followed by bioinformatics analysis was used to understand the abnormal biological processes of nucleus pulposus cells cultured in high-glucose medium. Diabetes mellitus rat models were established and histopathological and immunohistochemical analysis was conducted to examine nucleus pulposus tissue senescence in vivo. Exposure to a high glucose concentration promoted human nucleus pulposus cell senescence and increased the senescence-related secretion phenotype in human nucleus pulposus cells in vitro and in rat nucleus pulposus tissue in vivo. Bioinformatics analysis showed that hub genes were involved in nucleus pulposus cell cycle activities and cell senescence. The results suggest that appropriate blood glucose control may be key to preventing intervertebral disc degeneration in diabetic patients.

Cage migration after unilateral instrumented transforaminal lumbar interbody fusion and associated risk factors: a modified measurement method.

OBJECTIVE: In this retrospective study, a modified measurement method was used to analyze cage migration during follow-up after unilateral instrumented transforaminal lumbar interbody fusion (TLIF) and identify associated factors. METHODS: We retrospectively evaluated 75 patients who had been treated with unilateral instrumented TLIF. Cage migration was quantitatively defined as anterior-posterior or lateral displacement of the cage. RESULTS: Five patients had significant cage migration (6.7%), but none developed severe neural symptoms during follow-up or underwent reoperation. The cages tended to migrate posteriorly or toward the side of surgery. The initial cage position and patient age were strongly associated with migration. Migration was less frequent when the cages were initially placed closer to the side of surgery. Patients of advanced age were more likely to develop anterior-posterior migration than were young patients. CONCLUSION: Cage migration is related to the initial position of the cage. Particular attention is required when performing unilateral instrumented TLIF in patients of advanced age because they are most likely to develop cage migration. Quantification of cage migration is an effective method of exploring the associated factors.

Translaminar facet joint screw insertion with a rapid prototyping guide template: a cadaver study.

It is technically demanding and requires rich experience to insert the translaminar facet screw(TFS) via the paramedian mini-incision approach. It seems that it is easy to place the TFS using computer-assisted design and rapid prototyping(RP) techniques. However, the accuracy and safety of these techniques is still unknown. The aim of this study is to assess the accuracy and safety of translaminar facet screw placement in multilevel unilateral transforaminal lumbar interbody fusion using a rapid prototyping drill guide template system. A patient-matched rapid prototyping translaminar facet screw guide was examined in fourteen cadaveric lumbar spine specimens. A three-dimensional (3D) preoperative screw trajectory was constructed using spinal computed tomography scans, from which individualized guides were developed for the placement of translaminar facet screws. Following bone tunnel establishment, the 3D positioning of the entry point and trajectory of the screws was compared to the preoperative plan as found in the Mimics software.Among 60 trajectories eligible for assessment, no cases of clinically significant laminar perforation were found. The mean deviation between the planned and the actual starting points on spinous process was 1.22 mm. The mean tail and submergence angle deviation was found to be 0.68°and 1.46°, respectively. Among all the deviations, none were found to have any statistical significance. These results indicate that translaminar facet screw placement using the guide system is both accurate and safe.

Biomechanical evaluation of different surgical procedures in single-level transforaminal lumbar interbody fusion in vitro.

BACKGROUNDS: A variety of improved surgical methods were adopted in the transforaminal lumbar interbody fusion. A mechanical stability provides an ideal environment for the formation of a fusion mass and is the basis of their good outcomes. The object of this study is to evaluate the initial similarities and differences of four commonly-used posterior surgical procedures biomechanically. METHODS: Biomechanical testing was performed at L3-4 motion segment in 6 fresh-frozen human cadaveric lumbar spines (L2-L5), including the following sequentially tested configurations: 1) intact motion segment; 2) bilateral pedicle screw fixation; 3) unilateral pedicle screw fixation; 4) unilateral pedicle screw plus contralateral translaminar facet joint screw fixation according to the Magerl technique; and 5) bilateral pedicle screw fixation with bilateral facetectomies. The range of motion, neutral zone and stiffness of each method and intact segment were collected and compared. FINDINGS: All of four methods reduce the range of motion significantly in flexion and extension and lateral bending but not in axial torsion compared with the native segment. There is no significant difference among four procedures about the range of motion in all loading modes. All of methods increase the stiffness of segmental motion compared with intact segment in all loading modes, but only bilateral pedicle screw fixation showed significant increases in stiffness in flexion and extension(p=0.02) and lateral bending(p=0.023). The stiffness offered by instrumented constructs in different methods showed no significant difference in all loading modes. INTERPRETATION: The stiffness offered by four different posterior fixations in single segmental transforaminal lumbar interbody fusion is not significantly different.

Unilateral Versus Bilateral Pedicle Screw Fixation in Transforaminal Lumbar Interbody Fusion: A Monocentric Study of 215 Patients With a Minimum of 4-Year Follow-up.

STUDY DESIGN: A retrospective clinical study. OBJECTIVE: This study sought to retrospectively compare the mid-term to long-term outcomes between unilateral pedicle screw (UPS) and bilateral pedicle screw (BPS) augmented transforaminal lumbar interbody fusion (TLIF) in lumbar degenerative diseases. SUMMARY OF BACKGROUND DATA: Recently, UPS fixation has been applied in TLIF, for its satisfactory clinical outcome, less implants and less invasiveness. However, only short-term outcome has been reported, the mid-term to long-term outcome has not been well characterized. MATERIALS AND METHODS: From June 2007 to February 2011, 215 of 348 consecutive patients suffering from lumbar degenerative diseases were operated in our hospital and accomplished a minimum of 4-year follow-up. These patients were divided into 2 groups according to the operative techniques: UPS group (n=109), and bilateral pedicle screw group (n=106). Operative time, blood loss, length of hospital stay, hospital bill, fusion status, and complications were recorded and analyzed statistically. Visual analog scale, Oswestry disability index, and Japanese Orthopaedic Association scores were used to assess the preoperative and postoperative pain and functional outcome. RESULTS: The mean follow-up duration was 52.2 months. A significant decrease occurred in operative time, blood loss, and hospital bill in unilateral group, compared with bilateral group (P<0.05). The average postoperative visual analog scale, Oswestry disability index, and Japanese Orthopaedic Association scores improved significantly in each group than the preoperative counterparts (P<0.05); however, there were no significant difference between groups at any follow-up time point (P>0.05). No statistically difference was detected regarding fusion rate and complication rate between the 2 groups (P>0.05), except the cage migration rate (P<0.05). CONCLUSIONS: UPS fixation could achieve satisfactory clinical outcome similar to bilateral fixation in TLIF at a mid-term to long-term follow-up. To avoid cage migration, bullet-shaped cages should not be used in the unilateral group.

Miniopen Transforaminal Lumbar Interbody Fusion with Unilateral Fixation: A Comparison between Ipsilateral and Contralateral Reherniation.

The aim of this study was to evaluate the risk factors between ipsilateral and contralateral reherniation and to compare the effectiveness of miniopen transforaminal lumbar interbody fusion (TLIF) with unilateral fixation for each group. From November 2007 to December 2014, clinical and radiographic data of each group (ipsilateral or contralateral reherniation) were collected and compared. Functional assessment (Visual Analog Scale (VAS) score and Japanese Orthopaedic Association (JOA)) and radiographic evaluation (fusion status, disc height, lumbar lordosis (LL), and functional spine unit (FSU) angle) were applied to compare surgical effect for each group preoperatively and at final followup. MacNab questionnaire was applied to further evaluate the satisfactory rate after the discectomy and fusion. No difference except pain-free interval was found between ipsilateral and contralateral groups. There was a significant difference in operative time between two groups. No differences were found in clinical and radiographic data for assessment of surgical effect between two groups. The satisfactory rate was decreasing in both groups with time passing after discectomy. Difference in pain-free interval may be a distinction for ipsilateral and contralateral reherniation. Miniopen TLIF with unilateral pedicle screw fixation can be a recommendable way for single level reherniation regardless of ipsilateral or contralateral reherniation.

Etiology for Degenerative Disc Disease.

Degenerative disc disease is a multifaceted progressive irreversible condition and an inevitable part of aging, which has been found to be a contributing factor for low back pain and might cause radiculopathy, myelopathy, spinal stenosis, degenerative spondylolisthesis, and herniations. Its etiology is complex and multifactorial. Although genetics influence more dominant, the occupational and mechanical influences still persist as a major risk factor. This review emphasizes up-to-date knowledge regarding etiology of disc degeneration with special consideration on occupational, lifestyle factors, and genetic polymorphisms.

A biomechanical comparison of 3 different posterior fixation techniques for 2-level lumbar spinal disorders.

OBJECT: This study sought to make a biomechanical comparison of 3 different posterior fixation techniques for 2-level lumbar spinal disorders. METHODS: Eight fresh-frozen human cadaver lumbar spines (4 from L-1 to L-5, 4 from L-1 to S-1) were tested by applying pure moments of ± 8 Nm. Each specimen was first tested intact, and then the left facetectomies of L3-4 and L4-5 were performed to establish an unstable condition without removal of discs. Three instrumentation systems were then tested randomly: unilateral pedicle screw (UPS), UPS with contralateral translaminar facet screw (UPSFS), and bilateral pedicle screw (BPS). The range of motion (ROM) and the neutral zone (NZ) of L3-5 were measured. RESULTS: All fixation types could reduce the ROM of L3-5 significantly in flexion, extension, and lateral bending, compared with the intact state. In axial torsion, only BPS reduced the ROM significantly, compared with the intact state. The UPSFS technique provided intermediate stability, which was superior to the UPS in flexion-extension and lateral bending, and inferior to the BPS in lateral bending. Compared with the intact state, the NZs decreased significantly for UPS, UPSFS, and BPS in flexion-extension, while not significantly in lateral bending and axial torsion. CONCLUSIONS: In this study, among the 3 fixation techniques, BPS offered the highest stability, UPSFS provided intermediate stability, and UPS was the least stable for 2-level lumbar spinal disorders. UPSFS appeared to be able to offer a less invasive choice than BPS in well-selected patients with 2-level lumbar spinal disorders.

Comparison of three different posterior fixation techniques in transforaminal lumbar interbody fusion for two-level lumbar degenerative diseases: At a mean follow up time of 46 months.

OBJECTIVES: This study sought to retrospectively compare three different posterior fixation techniques in transforaminal lumbar interbody fusion for two-level lumbar degenerative diseases. PATIENTS AND METHODS: This was a retrospective single-center study including 84 patients who underwent TLIF instrumented with unilateral pedicle screws (UPS), unilateral pedicle screws plus contra-lateral translaminar facet screws (UPSFS), or bilateral pedicle screws (BPS) between June 2008 and May 2012. These patients were divided into three groups: UPS (n=22), UPSFS (n=28) and BPS (n=34) group. Operative time, blood loss, length of hospital stay, hospital bill, fusion status and complications were recorded and analyzed statistically. Visual analog scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopaedic Association Scores (JOA) were used to assess the preoperative and postoperative pain and functional outcome. Sagittal alignment was evaluated by the segment lordosis (SL) and whole lumbar spine lordosis (LL). RESULTS: The mean follow up duration was 46.2 (ranging from 36 to 60) months. A significant decrease occurred in operative time, blood loss and hospital bill in UPS and UPSFS group, compared with BPS group (p<0.05). The average postoperative VAS, ODI and JOA scores improved significantly in each group than the preoperative counterparts (p<0.05), however, there were no significant difference between groups at any follow-up time point (p>0.05). No statistically difference was detected regarding fusion rate and complication rate between groups (p>0.05), except the screw/rod failure rate (p<0.05). Radiographic analysis showed that the LLs in all these groups got improved (p<0.05) and the SLs maintained (p>0.05). CONCLUSION: UPS or UPSFS instrumented TLIF could achieve satisfactory mid-term clinical outcome comparable to BPS's, with less surgical time, less blood loss, and lower cost; UPS should be prudently performed for two-level cases in case of lower fusion rate, and cannulated screws should be replaced by stronger solid screws in UPSFS to reduce facet screw breakage.

The combined use of unilateral pedicle screw and contralateral facet joint screw fixation in transforaminal lumbar interbody fusion.

PURPOSE: This paper is to evaluate the efficacy and safety of transforaminal lumbar interbody fusion (TLIF) using unilateral pedicle screws along with contralateral translaminar facet joint screw (UPS+TFS) fixation in comparison with the method using bilateral pedicle screws fixation (BPS) in degenerative lumbar diseases. METHODS: Forty patients with single-level lumbar diseases were divided into two groups randomly. One group was treated by TLIF with BPS fixation while the other group was treated by the new technique with UPS+TFS fixation. The preoperative and postoperative ODI, JOA, VAPS scores, mean operation time, mean operation blood loss, fusion rate and complications were collected for comparison under two surgical methods. In terms of complications, only two cases of superficial infection in the BPS group and one case of urinary tract infection in the other group was found. RESULTS: The mean operation time and blood loss was significantly less in UPS+TFS group than in BPS group. The preoperation and postoperative ODI, JOA and VAPS at the intervals of 6 weeks, 3, 6 months and 1 year between the BPS and UPS+TFS group showed no significant disparities. Only one patient in UPS+TFS group was not fused with pseudoarthrosis formation. CONCLUSIONS: The clinical efficacy and safety of TLIF with UPS+TFS fixation were comparable to BPS fixation; however, the soft tissue injury and the corresponding operation cost were reduced with unilateral pedicle screw plus translaminar facet screw fixation.

Clinical outcomes and sagittal alignment of single-level unilateral instrumented transforaminal lumbar interbody fusion with a 4 to 5-year follow-up.

PURPOSE: A retrospective study was designed to evaluate clinical outcomes and sagittal alignment following single-level unilateral instrumented transforaminal lumbar interbody fusion (TLIF). METHODS: From November 2008 to December 2010, a total of 139 patients, who suffered from single-level lumbar degenerative disease, were included in this study. Forty-seven males and seventy-two females with a mean age of 57.3 years were enrolled. The average follow-up period was 51.7 months with a range of 41-66 months. The follow-up rate was 85.6 %. Thirty-one patients had diagnosis of discogenic low back pain, ten had recurrent disk herniation, thirty-four had spinal stenosis, and fourty-four had spondylolisthesis. Clinical outcomes were evaluated using the Oswestry disability index (ODI), visual analog scale (VAS) and Japanese Orthopedic Association. Operating time, blood loss, length of stay, and complications were also evaluated. The sagittal alignment and fusion status were assessed by X-ray and three-dimensional computed tomography. RESULTS: The average operating time was 92.1 ± 27.5 min, the average blood loss was 135.1 ± 113.5 ml, and the average length of stay was 12.0 ± 2.9 days. The overall complication rate was 13.4 %, and the fusion rate was 82.4 %. The postoperative clinical outcomes and sagittal alignment were significantly different from the preoperative values. The final lumbar lordosis angle and segment lordosis angle were associated with back pain VAS and ODI scores, respectively. CONCLUSION: Unilateral instrumented TLIF is a safe and effective treatment option for single-level lumbar degenerative disease, and is less invasive, yields good outcomes and has a low complication rate. In addition, the procedure has the potential to partly restore sagittal alignment.

Transforaminal lumbar interbody fusion using unilateral pedicle screw fixation plus contralateral translaminar facet screw fixation in lumbar degenerative diseases.

BACKGROUND: Transforaminal lumbar interbody fusion (TLIF) has been used in lumbar degenerative diseases. Some researchers have applied unilateral fixation in TLIF to reduce operational trauma without compromising the clinical outcome, but it is always suspected biomechanically unstable. The supplementary contralateral translaminar facet screw (cTLFS) seemed to be able to overcome the inherent drawbacks of unilateral pedicle screw (uPS) fixation theoretically. This study evaluates the safety, feasibility and efficacy of TLIF using uPS with cTLFS fixation in the treatment of lumbar degenerative diseases (LDD). MATERIALS AND METHODS: 50 patients (29 male) underwent the aforementioned surgical technique for their LDD between December 2009 and April 2012. The results were evaluated based on visual analogue scale (VAS) of the leg and back, Japanese Orthopedic Association (JOA) score and Oswestry Disability Index (ODI) were recorded. The radiographic examinations in form of X-ray, computed tomography (CT) or magnetic resonance imaging was done preoperatively and 1 week, 3 months, 6 months, 12 months and 24 months postoperatively. The student t-test was used for comparison between the preoperative values and postoperative counterparts. P < 0.05 was considered to be statistically significant. RESULTS: Among 50 patients, 22 received one level fusion and 28 two level's, with corresponding operation time and estimated blood loss being approximately 90 min, 150 ml and 120 min, 200 ml, respectively. No severe complications happened perioperatively. The mean VAS (back, leg) scores dropped from (7.6, 7.5) preoperatively to (2.1, 0.6) at 12 months' followup, ODI from 49.1 preoperatively to 5.6 and JOA score raised from 10.6 preoperatively to 28.5, all P < 0.001, suggesting of good clinical outcome. From the three-dimensional reconstructed CT, 62 out of 70 segments displayed solid fusion with fusion rate of 88.6% at 12 months postoperatively. CONCLUSIONS: TLIF using uPS fixation plus cTLFS fixation is a safe, feasible and effective technique in the treatment of one or two level lumbar degenerative diseases short termly.

Comparing the process of creeping substitution between allograft bone and local bone grafting in lumbar interbody fusion.

PURPOSE: A self-control study was designed to compare the process of creeping substitution between allograft bone and local bone grafting in lumbar interbody fusion. METHODS: From December 2011 to July 2012, 81 patients (mean age: 56.4) were included in this study and randomly allocated to two groups. Leopard cages were using in unilateral instrumentation transforaminal lumbar interbody fusion. In group 1, the cages were filled with the local bone on the side of the instrumentation and allograft bone on the other side. In group 2, they were totally filled with the local bone chips. Then, the special CT-reconstructions were made at 6- and 12-month follow-up. On the sagittal section, the sections of CT-reconstructions were perpendicular to the lateral axis of the cage from the side of the cage to the other side. Similarly, they were parallel to the lateral axis of the cage on the coronal section and intervertebral space on the cross section. The mean area size of bone mass on both sides of the cage was calculated, respectively, using image analysis software (Osirix, version 3.3.2) on each section in two groups. RESULTS: In group 1, at 6- and 12-month follow-up, significant differences were observed in the mean area size of bone mass between allograft bone and local bone grafting on the coronal, cross, and sagittal section. In group 2, the mean area size of local bone on both sides of the cage had no significant differences at 6- and 12-month follow-up on each section. CONCLUSIONS: The results of our study showed a superiority of local bone grafting over allograft bone.

Finite element analysis of 3 posterior fixation techniques in the lumbar spine.

This study compared the biomechanics of 3 fixation techniques: bilateral pedicle screw (BPS) fixation, unilateral pedicle screw (UPS) fixation, and UPS supplemented with translaminar facet screw (UPS+TLFS) fixation. The study was conducted in an L3-L5 finite element model. Three different finite element models were created by adopting different fixation techniques after removal of the left L3-L4 and L4-L5 facet joints. A 500-N compressive preload combined with 8-NM moment were applied in 3 finite element models with 3 fixation techniques during different movements. Angular displacement and stress distribution were recorded. As described in this article, the UPS model had the most variation in angular displacement, the BPS model was intermediate, and the UPS+TLFS model had the least mobility. Most of the stress accumulated on the body and tail of the pedicle screws and the connecting rods in the UPS and BPS models, but stress accumulated on the rods and the part of the facet joint pierced by the TLFS in the UPS+TLFS model. The middle part of the pedicle screw endured little stress compared with the upper and lower parts. The maximum stress on the fixation devices was highest in the UPS model. The maximum stress in the UPS+TLFS model was the lowest among the 3 models. Biomechanically, UPS+TLFS fixation is superior to either UPS fixation or BPS fixation in improving stability and reducing stress. Bilateral pedicle screw fixation is intermediate, and UPS fixation is inferior.

Transforaminal lumbar interbody fusion using a modified distractor handle: a midterm clinicoradiological follow-up study.

In current TLIF practice, the choice of the cage size is empirical and primarily depends on the case volume and experience of the surgeon. We used a self-made modified distractor handle in TLIF procedure with the goal of standardizing the intervertebral space tension and determining the proper cage size.

Quantitative assessment of the effect of ABCA1 gene polymorphism on the risk of Alzheimer's disease.

ATP-binding cassette transporter A1 (ABCA1) is a membrane-associated protein which has attracted considerable attention as a candidate gene for Alzheimer's disease (AD) based on its function as a key factor in lipid metabolism by mediating cellular cholesterol efflux, the rate-limiting step in the production of nascent high-density lipoprotein (HDL) particles. The relationship between ABCA1 common variations (R219 K rs2230806, I883 M rs4149313 and R1587 K rs2230808) and AD has been reported in various ethnic groups; however, these studies have yielded contradictory results. To investigate this inconsistency, we performed a meta-analysis of 13 studies involving a total of 12,248 subjects to evaluate the effect of ABCA1 on genetic susceptibility for AD. Overall, the summary OR of AD was 1.01 (95 % CI: 0.93-1.10; P = 0.77), 1.10 (95 % CI: 0.96-1.26; P = 0.16), and 1.08 (95 % CI: 0.96-1.23; P = 0.21) for R219 K, I883 M and R1587 K polymorphism, respectively. No significant results were observed in dominant and recessive when compared with wild genotype for these polymorphisms. In the stratified analyses by ethnicity and sample size, no evidence of any gene-disease association was obtained. In conclusion, the present meta-analysis does not support the notion that common SNPs on ABCA1 is a major genetic risk factor for AD.

Neuroserpin upregulates in the early period of sustained spinal cord compression.

BACKGROUND: Neuroserpin (NSP) is a neuroprotective factor in the situation of ischemia of a brain, such as stroke. However, it has never been reported in the spinal cord, which is part of the central nervous system (CNS). METHODS: The expression of NSP was detected using Western blotting and neuron apoptosis detected by TUNEL staining following spinal cord ischemia caused by sustained compression in rats. RESULTS: The results showed that NSP was upregulated in the injury area of spinal cord, accompanied with the activation of micorglia and tissue plasminogen activator (tPA), which suggested that NSP also plays a neuroprotective role in spinal cord compression since neuronal apoptosis appears when NSP returns to normal levels or even lower. CONCLUSIONS: NSP upregulates in early periods of sustained spinal cord compression.

Short-term outcome of bilateral decompression via a unilateral paramedian approach for transforaminal lumbar interbody fusion with unilateral pedicle screw fixation.

The purpose of this study was to evaluate the clinical and radiologic outcomes of bilateral decompression via a unilateral paramedian approach for transforaminal lumbar interbody fusion. Forty consecutive patients satisfying the inclusion criteria were divided randomly into groups 1 and 2. Patients were treated with unilateral (group 1) or bilateral (group 2) pedicle screw fixation and bilateral decompression via 1-sided (group 1) or bilateral (group 2) paramedian approach. Perioperative parameters (operation time, blood loss, hospital stay, complications, and implant cost), clinical outcome parameters (Japanese Orthopedic Association [JOA] scores, visual analog scale [VAS] scores, and Oswestry Disability Index [ODI] preoperatively and at 1 week and 3 months postoperatively), and radiologic parameters (radiograph and computed tomography [CT] scan preoperatively and at 1 week postoperatively) were compared.No differences were seen between groups 1 and 2 with respect to operation time, blood loss, or hospital stay. No complications were observed in either group. The ODI, JOA, and VAS values of both groups showed significant differences between the preoperative and 1-week or 3-month postoperative values. No significant differences were seen in the improvements of the ODI, JOA, and VAPS values between groups 1 and 2 at any postoperative time point. Postoperative CT indicated that the contralateral decompression was sufficient in both groups.The short-term results indicate that bilateral decompression via a unilateral paramedian approach for transforaminal lumbar interbody fusion with unilateral pedicle screw fixation is safe, feasible, and effective over the short-term and is more cost-efficient than a bilateral paramedian approach.

Renal insufficiency after liver transplantation in the MELD era compared to the pre-MELD era.

Because the model for end-stage liver disease (MELD) system for liver allocation gives priority to patients with a higher creatinine, and because pre-transplant renal function is one determinant of post-transplant renal function, this study compares the burden of renal insufficiency in the pre-MELD and MELD eras. Two hundred and eleven patients, at our institution, transplanted in the pre-MELD era, were compared to 143 in the MELD era. The GFR (mL/min/1.73 m2) was significantly higher in the MELD cohort than the pre-MELD cohort at time of transplant, discharge, and 12 months post-transplant (95.5 vs. 85.3, p = 0.039; 90.4 vs. 77.4, p = 0.002; 66.8 vs. 60.3, p = 0.026). There was no difference between the two groups in time to renal failure. There was a higher rate of sirolimus use in the MELD era (27% vs. 18%: p = 0.042) and a slightly higher use of kidney-liver transplant in the MELD era (p = 0.056). We did not identify greater renal insufficiency in the MELD era. There was greater renal function in the MELD era at time of transplant, discharge and month 12. Potential explanations include: absence of an increase in renal insufficiency prior to transplant in the MELD era, greater use of renal sparing immunotherapy and growing use of kidney-liver transplant.