Posterolateral Lumbar Research Articles

P63. Current incidence of adjacent segment pathology following lumbar fusion versus motion preserving procedures: a systematic review and meta-analysis of recent projections

P63. Current incidence of adjacent segment pathology following lumbar fusion versus motion preserving procedures: a systematic review and meta-analysis of recent projections

Evaluation of synthetic ceramics as compression resistant matrix to promote osteogenesis of autologous blood coagulum containing recombinant human bone morphogenetic protein 6 in rabbit posterolateral lumbar fusion model.

Posterolateral lumbar fusion (PLF) is a commonly performed surgical procedure for the treatment of pathological conditions of the lumbosacral spine. In the present study, we evaluated an autologous bone graft substitute (ABGS) containing rhBMP6 in autologous blood coagulum (ABC) and synthetic ceramics used as compression resistant matrix (CRM) in the rabbit PLF model. In the pilot PLF rabbit experiment, we tested four different CRMs (BCP 500-1700 μm, BCP 1700-2500 μm and two different TCP in the form of slabs) which were selected based on achieving uniform ABC distribution. Next, ABGS implants composed of 2.5 mL ABC with 0.5 g ceramic particles (TCP or BCP (TCP/HA 80/20) of particle size 500-1700 μm) and 125 μg rhBMP6 (added to blood or lyophilized on ceramics) were placed bilaterally between transverse processes of the lumbar vertebrae (L5-L6) following exposition and decortication in 12 New Zealand White Rabbits observed for 7 weeks following surgery. Spinal fusion outcome was analysed by μCT, palpatory segmental mobility testing and selected specimens were either tested biomechanically (three-point bending test) and/or processed histologically. The total fusion success rate was 90.9% by both μCT analyses and by palpatory segmental mobility testing. The volume of newly formed bone between experimental groups with TCP or BCP ceramics and the different method of rhBMP6 application was comparable. The newly formed bone and ceramic particles integrated with the transverse processes on histological sections resulting in superior biomechanical properties. The results were retrospectively found superior to allograft devitalized mineralized bone as a CRM as reported previously in rabbit PLF. Overall, this novel ABGS containing rhBMP6, ABC and the specific 500-1700 μm synthetic ceramic particles supported new bone formation for the first time and successfully promoted posterolateral lumbar fusion in rabbits.

Duration of Symptoms Does Not Affect Clinical Outcome After Lumbar Arthrodesis.

Retrospective cohort study at a single institution. To examine the effect of symptom duration on clinical outcomes after posterolateral lumbar fusion. Nonoperative measures are generally exhausted before patients are indicated for surgical intervention, leaving patients with their symptomatology for varying lengths of time. It is unclear at what point in time surgical intervention may become less efficacious at alleviating preoperative symptoms. Consecutive patients who underwent primary elective open posterior lumbar spinal fusion at a single academic institution were included. Patient and operative characteristics were compared between symptom duration groups (group 1: <12 mo of pain, group 2: ≥12 mo of pain). Preoperative and final postoperative visual analog scale back/leg pain, and Oswestry Disability Index, were collected. Preoperative, immediate postoperative, and final radiographs were assessed to measure lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and the PI-LL difference was calculated. In total, 167 patients were included in group 1, whereas 359 patients were included in group 2. Baseline demographics and operative characteristics were similar between the 2 groups. Both groups had similar changes in sagittal parameters and had no significant difference in rates of complication, reoperation, discharge to rehabilitation facility, or early adjacent segment degeneration. Both groups demonstrated similar improvement in clinical outcome measures. Despite differences in symptom duration, patients who had pain for ≥12 months demonstrated similar improvement after posterolateral lumbar arthrodesis than those who had pain for <12 months. Extended effort of conservative treatments or delay of operative intervention does not appear to negatively impact the eventual outcome of surgery. Level III.

The temporal and spatial expression of sclerostin and Wnt signaling factors during the maturation of posterolateral lumbar spine fusions.

The bone healing environment in the posterolateral spine following arthrodesis surgery is one of the most challenging in all of orthopedics and our understanding of the molecular signaling pathways mediating osteogenesis during spinal fusion is limited. In this study, the spatial and temporal expression pattern of Wnt signaling factors and inhibitors during spinal fusion was assessed for the first time. Bilateral posterolateral spine arthrodesis with autologous iliac crest bone graft was performed on 21 New Zealand White rabbits. At 1‐, 2‐, 3‐, 4‐, and 6‐weeks, the expression of sclerostin and a variety of canonical and noncanonical Wnts signaling factors was measured by qRT‐PCR from tissue separately collected from the transverse processes, the Outer and Inner Zones of the fusion mass, and the adjancent paraspinal muscle. Immunohistochemistry for sclerostin protein was also performed. Sclerostin and many Wnt factors, especially Wnt3a and Wnt5a, were found to have distinct spatial and temporal expression patterns. For example, harvesting ICBG caused a significant increase in sclerostin expression. Furthermore, the paraspinal muscle immediately adjacent to the transplanted ICBG also had significant increases in sclerostin expression at 3 weeks, suggesting new potential mechanisms for pseudarthroses following spinal arthrodesis. The presented work is the first description of the spatial and temporal expression of sclerostin and Wnt signaling factors in the developing spine fusion, filling an important knowledge gap in the basic biology of spinal fusion and potentially aiding in the development of novel biologics to increase spinal fusion rates.

Uniportal Full Endoscopic Posterolateral Transforaminal Lumbar Interbody Fusion with Endoscopic Disc Drilling Preparation Technique for Symptomatic Foraminal Stenosis Secondary to Severe Collapsed Disc Space: A Clinical and Computer Tomographic Study with Technical Note

Background: Severe collapsed disc secondary to degenerative spinal conditions leads to significant foraminal stenosis. We hypothesized that uniportal posterolateral transforaminal lumbar interbody fusion with endoscopic disc drilling technique could be safely applied to the collapsed disc space to improve patients’ pain score, restore disc height, and correct the segmental angular parameters. Methods: We included patients who met the indication criteria for lumbar fusion and underwent uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion with pre-operative Computer Tomography mid disc height of less than or equal to 5 mm and MRI of Grade 3 Foraminal Stenosis. Visual analogue scale and computer tomography pre-operative and post-operative sagittal disc height in the anterior, middle and posterior part of the disc; sagittal focal segmental angle; mid coronal disc height and coronal wedge angles were evaluated. Results: 30 levels of Endo-TLIF were included, with a mean follow up of 12 months. The mean improvement in decreasing pain score was 2.5 ± 1.1, 3.2 ± 0.9 and 4.3 ± 1.0 at 1 week post operation, 3 months post operation and at final follow up, respectively, p < 0.05. There was significant increase in mid sagittal computer tomographic anterior, middle and posterior disc height of 6.99 ± 2.30, 6.28 ± 1.44, 5.12 ± 1.79 mm respectively, p < 0.05. CT mid coronal disc height showed an increase of 7.13 ± 1.90 mm, p < 0.05. There was a significant improvement in the CT coronal wedge angle of 2.35 ± 4.73 and the CT segmental focal sagittal angle of 1.98 ± 4.69, p < 0.05. Conclusion: Application of Uniportal Endoscopic Posterolateral Lumbar Interbody Fusion in patients with severe foraminal stenosis secondary to severe collapsed disc space significantly relieved patients’ pain and restored disc height without early subsidence or exiting nerve root dysesthesia in our cohort of patients.

Technical Considerations of Uniportal Endoscopic Posterolateral Lumbar Interbody Fusion: A Review of Its Early Clinical Results in Application in Adult Degenerative Scoliosis

Uniportal endoscopic posterolateral lumbar interbody fusion (Endo-TLIF) provides one of the least invasive forms of minimally invasive surgery, allowing large size cages which are commercially available for open and tubular microscopic transforaminal lumbar interbody fusion (TLIF) to be inserted through this approach. We studied the effect of such a technique on a series of patients with low-grade degenerative scoliosis. Endo-TLIF was applied to patients who had 10°-40° of degenerative adult scoliosis. Pre- and postoperative 1-week, 3-month, and final follow-up clinical status of visual analog scale, Oswestry Disability Index, perioperative complications, and Macnab criteria were collected. Roentgenogram to assess changes in Cobb angles was done. There was statistically significant improvement of preoperative, 1-week postoperative, 3-month postoperative, and final follow-up mean of visual analog scale scores with 7.72 (5-10), 3.68 (3-6), 2.88 (2-4), and 1.96 (1-3), respectively, and with Oswestry Disability Index mean of 70.4 (52-86), 35.12 (26-56), 27.68 (24-38), and 24 (20-28), respectively (P < 0.05). In terms of Macnab criteria, 100% had good to excellent result. In terms of scoliosis measured by Cobb angle, there was statistically significant improvement. Endo-TLIF is a safe and effective procedure in mild to moderate degenerative scoliosis with good early clinical results and improvement in coronal Cobb angle. It can be considered as an option if a short segment(s) fusion is planned for adult degenerative scoliosis.

Comparison of Fusion Rate between Demineralized Bone Matrix versus Autograft in Lumbar Fusion : Meta-Analysis

The demineralized bone matrix (DBM) as the bone graft material to increase the fusion rate was widely used in spinal fusion. The current study aimed to compare the fusion rate of DBM to the fusion rate of autograft in lumbar spine fusion via meta-analysis of published literature. After systematic search, comparative studies were selected according to eligibility criteria. Checklist (risk of bias assessment tool for non-randomized study) was used to evaluate the risk of bias of the included nonrandomized controlled studies. The corresponding 95% confidence interval (95% CI) were calculated. We also used subgroup analysis to analyze the fusion rate of posterolateral lumbar fusion and lumbar interbody fusion. Eight studies were finally included in this meta-analysis. These eight studies included 581 patients. Among them, 337 patients underwent spinal fusion surgery using DBM (DBM group) and 204 patients underwent spinal fusion surgery with mainly autologous bone and without using DBM (control group). There was no significant differences of fusion rate between the two groups in posterolateral fusion analysis (risk ratio [RR], 1.03; 95% CI, 0.90–1.17; p=0.66) and interbody fusion analysis (RR, 1.13; 95% CI, 0.91–1.39; p=0.27). Based on the available evidence, the use of DBM with autograft in posterolateral lumbar spine fusion and lumbar interbody fusion showed a slightly higher fusion rate than that of autograft alone; however, there was no statistically different between two groups.

Posterolateral lumbar spine fusion with unidirectional porous beta-tricalcium phosphate in a canine model

We investigated the use of the autologous iliac bone and unidirectional porous beta-tricalcium phosphate (UDPTCP) in posterolateral lumbar spine fusion (PLF). Ten canine PLF models were prepared. Using only the autologous bone as the control group, 100%, 75%, 50%, and 25% groups were prepared according to the mixing ratios of UDPTCP. Radiological evaluation and histological analysis were performed 12weeks after surgery. Bone fusion was evaluated according to anteroposterior plain X-rays and coronal reconstruction CT views using four grades: 0 = no osteogenesis, 1 = only slight discontinuous osteogenesis between transverse processes, 2 = discontinuous osteogenesis between transverse processes, and 3 = continuous osteogenesis between transverse processes. Bone fusion determined by X-ray was 2.8 ± 0.5 in the control group, 0 in the 100% UDPTCP group (p = 0.02), 1.8 ± 0.5 (p = 0.03) in the 75% UDPTCP group, 2.5 ± 0.6 (p = 0.54) in the 50% UDPTCP group, and 2.8 ± 0.5 (p = 1.0) in the 25% UDPTCP group. The bone fusion score was significantly lower in the 75% and 100% UDPTCP groups than in the control group. Bone fusion determined by CT was 2.8 ± 0.5 in the control group, 1.0 ± 0.8 (p = 0.01) in the 100% UDPTCP group, 2.0 ± 0.0 (p = 0.02) in the 75% UDPTCP group, 2.5 ± 0.6 (p = 0.54) in the 50% UDPTCP group, and 2.8 ± 0.5 (p = 1.0) in the 25% UDPTCP group. Similar to the bone fusion determination by X-ray, the bone fusion score was significantly lower in the 75% and 100% UDPTCP groups. These data suggest that, in a canine PLF model, the appropriate mixing ratio of UDPTCP is 50% or less.

Autologous blood coagulum containing rhBMP6 induces new bone formation to promote anterior lumbar interbody fusion (ALIF) and posterolateral lumbar fusion (PLF) of spine in sheep.

In the present study, we evaluated an autologous bone graft substitute (ABGS) composed of recombinant human BMP6 (rhBMP6) dispersed within autologous blood coagulum (ABC) used as a physiological carrier for new bone formation in spine fusion sheep models. The application of ABGS included cervical cage for use in the anterior lumbar interbody fusion (ALIF), while for the posterolateral lumbar fusion (PLF) sheep model allograft devitalized bone particles (ALLO) were applied with and without use of instrumentation. In the ALIF model, ABGS (rhBMP6/ABC/cage) implants fused significantly when placed in between the L4-L5 vertebrae as compared to control (ABC/cage) which appears to have a fibrocartilaginous gap, as examined by histology and micro CT analysis at 16weeks following surgery. In the PLF model, ABGS implants with or without ALLO showed a complete fusion when placed ectopically in the gutter bilaterally between two decorticated L4-L5 transverse processes at a success rate of 88% without instrumentation and at 80% with instrumentation; however the bone volume was 50% lower in the instrumentation group than without, as examined by histology, radiographs, micro CT analyses and biomechanical testing at 27weeks following surgery. The newly formed bone was uniform within ABGS implants resulting in a biomechanically competent and histologically qualified fusion with an optimum dose in the range of 100μg rhBMP6 per mL ABC, while in the implants that contained ALLO, the mineralized bone particles were substituted by the newly formed remodeling bone via creeping substitution. These findings demonstrate for the first time that ABGS (rhBMP6/ABC) without and with ALLO particles induced a robust bone formation with a successful fusion in sheep models of ALIF and PLF, and that autologous blood coagulum (ABC) can serve as a preferred physiological native carrier to induce new bone at low doses of rhBMP6 and to achieve a successful spinal fusion.

Minimally Invasive Lumbar Decompression and Removal of Symptomatic Heterotopic Bone Formation After Spinal Fusion with Recombinant Human Bone Morphogenetic Protein-2

We present a case of symptomatic heterotopic bone formation following revision of posterolateral lumbar fusion/instrumentation and “off-label” use of recombinant human bone morphogenetic protein-2, treated successfully with the use of a minimally invasive tubular approach.

Comparing rates of early pedicle screw loosening in posterolateral lumbar fusion with and without transforaminal lumbar interbody fusion

Addition of interbody fusion via a transforaminal approach (TLIF) has become a popular surgical option for treatment of degenerative lumbar conditions. Although technically more complicated than posterolateral fusion surgery (PLF), it has been suggested that TLIF provides superior immediate stability and protects against early pedicle screw loosening. This theory has never been formally examined in a clinical study. To determine the impact of TLIF on early pedicle screw loosening and radiographic fusion rates compared with PLF using pedicle screws alone in the treatment of single level lumbar degenerative conditions. Retrospective computed tomography (CT) based review. One hundred ninety-three patients underwent TLIF+PLF with local autograft bone or PLF alone with local autograft bone. Radiographic fusion rates and screw loosening were measured at 6 and 12 months using strict CT criteria. Patient self-reported outcome measures included Visual Analog Scale for low back pain and leg pain and Oswestry Disability Index. Postoperative thin-cut CTs were examined for pedicle screw loosening and radiographic fusion status. Early screw loosening rates were determined using 6-month postoperative CT, whereas radiographic fusion rates were determined using 12-month postoperative CT. One-way analysis of variance was used to determine significant differences in mean outcome scores and other continuous measures between groups at baseline and follow-up. Chi-square test of independence or Fisher's exact test was used to compare proportions between groups on categorical measures. Eighty-three patients underwent TLIF+PLF (Group A) and 115 patients underwent PLF alone (Group B). At 6-month follow-up, loosening was observed in 49 of 792 total screws (6.19%). Of Group A, 7.23% of patients demonstrated loosening of one or more screws compared with 18.3% of Group B (Chi-Square value 4.98; p=.0256). Six-month radiographic fusion rates were 36.1% in Group A versus 44.3% in Group B. Twelve-month radiographic fusion rates increased to 58.6% in Group A versus 73.1% in Group B. Among Group A patients not yet fused at 6 months, screw loosening was associated with a 0% rate of radiographic fusion at 12 months versus 41.2% without screw loosening. Rates for Group B were 6.25% and 70.3%, respectively. Patient age was a significant independent predictor of loosening (p=.0336). TLIF appears to have a protective effect, reducing rates of early screw loosening by approximately 60% versus PLF. However, this effect appears independent of actual overall radiographic fusion rates which may be approximately 20% lower with TLIF at 12 months. TLIF may have advantages in patients where early loosening is a particular concern, for example, in the setting of increased patient age.

Recent Research Advances in Biologic Bone Graft Materials for Spine Surgery.

Biologic bone graft materials continue to be an important component of various spinal fusion procedures. Given the known risks and morbidity of harvesting iliac crest bone graft, the historical gold standard for spinal fusion, these biologic materials serve the purpose of improving both the efficacy and safety of spinal fusion procedures. Recent advances in biomedical and materials sciences have enabled the design of many novel materials that have shown promise as effective bone graft materials. This review will discuss current research pertaining to several of these materials, including functionalized peptide amphiphiles and other nanocomposites, novel demineralized bone matrix applications, 3D-printed materials, and Hyperelastic Bone®, among others. Recent investigation has demonstrated that novel technologies, including nanotechnology and 3D printing, can be used to produce biomaterials with significant osteogenic potential. Notably, peptide amphiphile nanomaterials functionalized to bind BMP-2 have demonstrated significant bone regenerative capacity in a pre-clinical rodent posterolateral lumbar fusion (PLF) model. Additionally, 3D-printed Hyperelastic Bone® has demonstrated promising bone regenerative capacity in several in vivo animal models. Composite materials such as TrioMatrix® (demineralized bone matrix, hydroxyapatite, and nanofiber-based collagen scaffold) have also demonstrated significant osteogenic potential in both in vitro and in vivo settings. Advances in materials science and engineering have allowed for the design and implementation of several novel biologic materials, including nanocomposites, 3D-printed materials, and various biologic composites. These materials provide significant bone regenerative capacity and have the potential to be alternatives to other bone graft materials, such as autograft and BMP-2, which have known complications.

Fusion and Healing Prediction in Posterolateral Spinal Fusion Using 18F-Sodium Fluoride-PET/CT

This study measures the total graft of 18F-sodium fluoride (NaF) uptake in non-instrumented posterolateral lumbar fusion (niPLF) patients one month after surgery and correlates it with the difference in the clinical findings between the baseline and one year after surgery. The walking distance (WLK-D), visual analog scale of back pain (VAS-B), VAS score of leg pain (VAS-L), tandem test (TAN), Oswestry Disability Index questionnaire (ODI), and European Quality of Life-5 Dimensions questionnaire (EQ-5D) were assessed before surgery and one year after. The graft NaF uptake was analyzed quantitatively with a fixed threshold algorithm resulting in the total graft uptake (SUVtotal) and partial volume corrected SUVtotal (cSUVtotal). Only 4 out of 18 patients experienced fusion; they had an insignificantly lower median total graft uptakes, i.e., 1178 SUVtotal vs. 1224 SUVtotal (p = 0.73) and 1282 cSUVtotal vs. 1231 cSUVtotal (p = 0.35), respectively. Similarly, fused patients experienced insignificantly larger pain decreases, i.e., median VAS-B 4.3 vs. 3.8 (p = 0.92) and VAS-L −6.4 vs. −4.4 (p = 0.2). We found an insignificant trend for a lower NaF uptake and less pain in fused patients. The NaF uptake did not correlate with the chronological change in the clinical parameters.

Tissue-engineered bone used in a rabbit model of lumbar intertransverse process fusion: A comparison of osteogenic capacity between two different stem cells.

Spinal fusion serves an important role in the reconstruction of spinal stability via restoration of the normal spinal sequence and relief of pain. Studies have demonstrated that the fusion rate is mainly associated with the osteogenic capacity of the implanted graft. Mesenchymal stem cells (MSCs) have been successfully isolated from human degenerated cartilage endplate (CEP) and designated as CEP-derived stem cells (CESCs). Previous studies have suggested that CESCs possesses in vitro and in vivo chondrogenic potential superior to that of bone marrow (BM)-MSCs. In addition, CESCs have shown a stronger in vitro osteogenic ability. The present study aimed to further determine the in vivo three-dimensional osteogenesis efficacy of CESCs for spinal fusion. Tissue-engineered bone grafts were transplanted into a rabbit model of posterolateral lumbar intertransverse process fusion using CESCs and BM-MSCs as seed cells composited with porous hydroxyapatite (PHA). The results of manual palpation and computed tomography (CT) scan reconstruction indicated that the CESCs/PHA group had a higher fusion rate than the BM-MSCs/PHA group, although the difference was not observed to be statistically significant. In addition, RT-qPCR results revealed that the in vitro CESCs/PHA composite expressed significantly higher levels of osteogenic-specific mRNA compared with the BM-MSCs/PHA composite. Finally, micro-CT and semi-quantitative histological analysis further demonstrated that the newly formed bone quality of the CESCs/PHA group was significantly higher than that of the BM-MSCs/PHA group in the intertransverse process fusion model. Therefore, the study indicated that CESCs possess superior in vivo osteogenesis capacity compared with BM-MSCs, and might serve as an important alternative seed cell source for bone tissue engineering. These results may provide the foundation for a biological solution to spinal fusion or other bone defect issues.

Does the Number of Levels Fused Affect Spinopelvic Parameters and Clinical Outcomes Following Posterolateral Lumbar Fusion for Low-Grade Spondylolisthesis?

Study Design:Retrospective cohort.Objectives:To determine how the number of fused intervertebral levels affects radiographic parameters and clinical outcomes in patients undergoing open posterolateral lumbar fusion (PLF) for low-grade degenerative spondylolisthesis.Methods:This was a retrospective cohort study on patients who underwent open PLF for low-grade spondylolisthesis at a single institution from 2011 to 2018. Patients were divided into groups based on number of levels fused during their procedure (1, 2, or 3 or more). Preoperative and postoperative spinopelvic radiographic parameters, patient-reported outcomes (Visual Analog Scale [VAS]-back, VAS-leg, Oswestry Disability Index [ODI]), and postoperative complications were compared.Results:Of the 316 patients eligible (203 one-level, 95 two-level, 18 three or more levels), change in initial postoperative to final pelvic incidence-lumbar lordosis was greatest in 2-level fusions (P = .039), while 3 or more level fusions had worse final pelvic tilt measures (P = .021). In addition, multilevel fusions had worse final VAS-back scores (2-level: P = .015; 3 or more levels: P = .011), higher rates of dural tears (2-level: P = .001), reoperation (2-level: P = .039), and discharge to facility (3 or more levels: P = .047) when compared with 1-level fusions.Conclusions:Patients in multilevel fusions experienced less improvement in back pain, had more complications, and were more commonly discharged to a facility compared with single-level PLF patients. These findings are important for operative planning, for setting appropriate preoperative expectations, and for risk stratification in patients undergoing posterior lumbar fusion for low-grade spondylolisthesis.

Efficacy of platelet-rich plasma in posterior lumbar interbody fusion: systematic review and meta-analysis.

We have conducted a systematic review and meta-analysis that aims to compare outcomes (pain VAS, fusion and adverse event) of PRP and placebo after posterolateral lumbar fusion (PLF) surgery. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Relevant studies were identified from Medline and Scopus from inception to September 16, 2019 that reported visual analog scale back pain, postoperative complications and fusions of either group. In a total of seven studies, two, two, three studies were RCT, prospective and retrospective studies, respectively. Overall, there were 270 patients (150 in the PRP group and 149 in the placebo group). Three, three, four, three, two, seven and four studies were reported for pain VAS back in 3months, 6months, 12months, 24months, period of fusion, postoperative fusion and adverse events, respectively. The unstandardized mean difference (UMD) VAS back in 3, 6, 6 and 24months was -0.41 (95%CI -0.87, 0.05) score, -0.97 (95%CI -1.68, -0.27) score, -0.33 (95%CI -0.61, -0.59) score, -0.19 (95%CI -1.00, 0.62) scores lower than placebo after posterolateral lumbar fusion (PLF) patients. The UMD period of bone union were -1.62 (95%CI -1.85, -1.39) months faster than placebo after PLF patients. A total of seven and four studies were reported fusion and adverse events between PRP and placebo group. No significant differences were noted for fusion and adverse events with the pooled RR of 1.03 (95%CI 0.48, 1.80) and 0.95 (95%CI 0.14, 6.56). PRP with autologous bone graft had lower back pain and faster bone union time than bone graft alone. While, there have no difference in fusion rate and adverse events in both groups. Larger, prospective randomized controlled studies are needed to confirm these findings as the current literature is still insufficient. Further research including cost of operation, postoperative function and satisfaction, quality of life and cost-efficacy analysis is required to determine whether the PRP with autologous bone graft is superior to bone graft alone or not. Level II.

Review of Risks and Complications of Extreme Lateral Interbody Fusion (XLIF).

Background:Extreme lateral interbody fusions (XLIF) and Minimally Invasive (MIS) XLIF were developed to limit the vascular injuries associated with anterior lumbar interbody fusion (ALIF), and minimize the muscular/ soft tissue trauma attributed to transforaminal lumbar interbody fusion (TLIF), posterior lumbar interbody fusion (PLIF), and posterolateral lumbar fusion (PLF).Methods:Nevertheless, XLIF/MIS XLIF pose significant additional risks and complications that include; multiple nerve injuries (e.g. lumbar plexus, ilioinguinal, iliohypogastric, genitofemoral, lateral femoral cutaneous, and subcostals (to the anterior abdominal muscles: abdominal oblique), and sympathectomy), major vascular injuries, bowel perforations/postoperative ileus, seromas, pseudarthrosis, subsidence, and reoperations.Results:The risks of neural injury with XLIF/MIS XLIF (up to 30-40%) are substantially higher than for TLIF, PLIF, PLF, and ALIF. These neural injuries included: lumbar plexus injuries (13.28%); new sensory deficits (0-75% (21.7%-40%); permanent 62.5%); motor deficits (0.7-33.6%-40%); iliopsoas weakness (9%-31%: permanent 5%), anterior thigh/groin pain (12.5-34%), and sympathectomy (4%-12%). Additional non-neurological complications included; subsidence (10.3%-13.8%), major vascular injuries (0.4%), bowel perforations, recurrent seroma, malpositioning of the XLIF cages, a 45% risk of cage-overhang, pseudarthrosis (7.5%), and failure to adequately decompress stenosis. In one study, reviewing 20 publications and involving 1080 XLIF patients, the authors observed “Most (XLIF) studies are limited by study design, sample size, and potential conflicts of interest.”Conclusion:Many new neurological deficits and other adverse events/complications are attributed to MIS XLIF/ XLIF. Shouldn’t these significant risk factors be carefully taken into consideration before choosing to perform MIS XLIF/XLIF?

Computer-assisted surgical navigation is associated with an increased risk of neurological complications: a review of 67,264 posterolateral lumbar fusion cases.

Pedicle screw malposition may result in neurological complications following posterolateral lumbar fusions (PLF). While computer-assisted navigation (NAV) and intraoperative neuromonitoring (ION) have been shown to improve safety in deformity surgeries, their use in routine PLFs remain controversial. This study assesses the risk of complications and reoperation for pedicle screw revision following PLF with and without ION and/or NAV surgery. Retrospective analyses were performed using the Truven Health MarketScan® databases to identify patients that had primary PLF with and without NAV and/or ION for degenerative lumbar disorders from years 2007-2015. Patients undergoing concomitant interbody fusions, spinal deformity surgery or fusion to the thoracic spine were excluded. Complications and reoperation for pedicle screw revision within 90 days of surgery were assessed. During the study period, 67,264 patients underwent PLFs. NAV only was used in 3.5% of patients, ION only in 17.9% and both NAV and ION in 0.8% of patients. In univariate analyses, there was a difference in the risk of neurological injuries among groups (NAV only: 1.4%, ION only: 0.8%, NAV and ION: 0.5%, No NAV or ION: 0.6%, P<0.001). In multivariable models, the use of NAV was associated with a higher risk of neurological complications when compared to ION only or no ION or NAV [NAV vs. ION only: odds ratio (OR) and 95% confidence interval (CI) =2.1 (1.4, 3.2), P=0.002; NAV vs. no ION or NAV: OR and 95% CI =2.5 (1.7, 3.5), P<0.001]. There was no difference in reoperation rates among the groups (P=0.135). Although the overall risk of neurological complications following PLFs is low, the use of NAV only was associated with an increased risk of neurological complications. No differences were observed in the rates of pedicle screw revision among groups.

The effect of insulin dependent diabetes on bone metabolism and growth after spinal fusion

STUDY DESIGNExperimental animal model. OBJECTIVEThe purpose of this study was to evaluate the hypothesis that insulin dependent diabetes mellitus (IDDM) will inhibit the formation of a solid bony union after spinal fusion surgery via an alteration of the microenvironment at the fusion site in a rat model. SUMMARY OF BACKGROUND DATAPrevious studies report diabetes mellitus (DM) and specifically IDDM as a risk factor for complications and poor surgical outcomes following spinal fusion. METHODSTwenty control and 22 diabetic rats were obtained at 5 weeks of age. At 20 weeks of age, all animals underwent posterolateral lumbar fusion surgery using a tailbone autograft with diabetic rats receiving an implantable time release insulin pellet. A subset of rats was sacrificed 1-week postsurgery for growth factor (PDGF, IGF-I, TGF-β, and VEGF) and proinflammatory cytokine ELISA analysis. All other rats were sacrificed 3-months postsurgery for fusion evaluation via manual palpation and micro CT. Glycated hemoglobin (HbA1c) was measured at surgery and sacrifice on all animals. RESULTSCompared with healthy rats undergoing spinal fusion, rats with IDDM demonstrated a significant reduction in manual palpation fusion rates (16.7% vs. 43%, p<.05). Average bone mineral density, bone volume, and bone volume fraction were also significantly reduced and negatively correlated to blood glucose levels. IL-1B, IL-5, IL-10, TNF-α, and KC/GRO were significantly elevated in fusion beds of IDDM rats. CONCLUSIONSThis study demonstrates that rats with IDDM demonstrate a reduced rate and quality of spinal fusion with increased local levels of inflammatory cytokines. Targeted modalities are required to improve bone healing in this growing, high-risk population. CLINICAL SIGNIFICANCEThis is the first translational animal model of IDDM to evaluate the rate and quality of spinal fusion while controlling for other surgical and patient-related risk factors. Our findings demonstrate the complex nature by which IDDM impairs bone healing and highlight the need for additional basic science research to further elucidate this mechanism in order to develop more effective therapeutic interventions.

Does increasing age impact clinical and radiographic outcomes following lumbar spinal fusion?

Background ContextDespite the growing senior population within the United States, there is a lack of consensus regarding the safety and efficacy of performing lumbar spinal fusion for this population. PurposeTo evaluate the clinical and radiographic outcomes in different age cohorts following lumbar spinal fusion. Study DesignRetrospective cohort analysis. Patient SampleAnalysis of 1,184 patients who underwent posterolateral lumbar fusion from 2011 to 2018. Surgery was indicated after failure of conservative treatment to address radiculopathy and/or neurogenic claudication. Patients were excluded if they were under 18 years of age at the time of surgery, had a lumbar fracture, tumor, or infection, or had fusions involving the thoracic spine, high-grade spondylolisthesis, or concomitant deformity. Of the 1,184 patients, 850 patients were included. Patients were divided into three roughly equal groups for analysis: young (18–54 years), middle-aged (55–69 years), and senior (≥70 years). Outcome MeasuresVisual Analog Scale Back/Leg pain, and Oswestry Disability Index (ODI) were collected, and achievement of minimal clinically important difference was evaluated. Lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), and PI-LL difference were measured on radiographs. Rates of postoperative complications were analyzed. MethodsSeveral radiographic parameters were measured using plain radiographs obtained at preoperative, immediately postoperative (standing radiographs performed on postoperative day 1), and most recent follow-up visits. Preoperative and final patient-reported outcomes, along with demographic information, were obtained all patients. Binary outcome variables were compared between groups with multivariate logistic regression, and continuous outcome variables were compared using multivariate linear regression, with age 18 to 54 years used as the reference. Multivariate regressions were used to compare outcomes between cohorts while controlling baseline characteristics. ResultsA total of 850 patients were included; 330 young (38.80%), 317 middle-aged (37.30%), and 203 senior (23.90%). Seniors had higher postoperative length of stay compared to younger patients (p<.001). Younger patients had worse final ODI scores compared to middle-aged patients (p=.002). Seniors had higher rates of proximal ASD (p=.002) compared to young patients. There was no difference in achievement of minimal clinically important differences (MCID) between all three groups. ConclusionsSenior patients have significant improvement in patient-reported clinical outcomes, despite having greater comorbidities, and longer length of stay. However, given a general lack of achievement of MCID across all cohorts, these findings suggest the need for a critical re-evaluation of the role of lumbar spinal fusion in the management of patients with refractory radiculopathic and/or neurogenic claudication symptoms.