SPINE

“Twilight in the Valley” No abstract available

Yves Cotrel and the Revolution of Scoliosis Surgery, in Memoriam No abstract available

Does Riluzole Influence Bone Formation?: An: In Vitro: Study of Human Mesenchymal Stromal Cells and Osteoblast Study Design. A post-test design biological experiment. Objective. The aim of this study was to evaluate the osteogenic effects of riluzole on human mesenchymal stromal cells and osteoblasts. Summary of Background Data. Riluzole may benefit patients with spinal cord injury (SCI) from a neurologic perspective, but little is known about riluzole's effect on bone formation, fracture healing, or osteogenesis. Methods. Human mesenchymal stromal cells (hMSCs) and human osteoblasts (hOB) were obtained and isolated from healthy donors and cultured. The cells were treated with riluzole of different concentrations (50, 150, 450 ng/mL) for 1, 2, 3, and 4 weeks. Cytotoxicity was evaluated as was the induction of osteogenic differentiation of hMSCs. Differentiation was evaluated by measuring alkaline phosphatase (ALP) activity and with Alizarin red staining. Osteogenic gene expression of type I collagen (Col1), ALP, osteocalcin (Ocn), Runx2, Sox9, Runx2/Sox9 ratio were measured by qRT-PCR. Results. No cytotoxicity or increased proliferation was observed in bone marrow derived hMSCs and primary hOBs cultured with riluzole over 7 days. ALP activity was slightly increased in hMSCs after treatment for 2 weeks with riluzole 150 ng/mL and slightly upregulated by 150% (150 ng/mL) and 90% (450 ng/mL) in hMSCs at 3 weeks. In hOBs, ALP activity almost doubled after 2 weeks of culture with riluzole 150 ng/mL (P < 0.05). More pronounced 2.6-fold upregulation was noticed after 3 weeks of culture with riluzole at both 150 ng/mL (P = 0.05) and 450 ng/mL (P = 0.05). No significant influence of riluzole on the mRNA expression of osteocalcin (OCN) was observed. Conclusion. The effect of riluzole on bone formation is mixed; low-dose riluzole has no effect on the viability or function of either hMSCs or hOBs. The activity of ALP in both cell types is upregulated by high-dose riluzole, which may indicate that high-dose riluzole can increase osteogenic metabolism and subsequently accelerate bone healing process. However, at high concentrations, riluzole leads to a decrease in osteogenic gene expression, including Runx2 and type 1 collagen. Level of Evidence: N/A

Unilateral Osteotomy of Lumbar Facet Joint Induces a Mouse Model of Lumbar Facet Joint Osteoarthritis Study Design. The lumbar facet joint (LFJ) osteoarthritis (OA) model that highly mimics the clinical conditions was established and evaluated. Objective. Here, we innovatively constructed and evaluated the aberrant mechanical loading-related LFJ OA model. Summary of Background Data. LFJ is the only true synovial joint in a functional spinal unit in mammals. The LFJ osteoarthritis is considered to contribute 15% to 45% of low back pain. The establish of animal models highly mimicking the clinical conditions is a useful tool for the investigation of LFJ OA. However, the previously established animal models damaged the LFJ structure directly, which did not demonstrate the effect of aberrant mechanical loading on the development of LFJ osteoarthritis. Methods. In the present study, an animal model for LFJ degeneration was established by the unilateral osteotomy of LFJ (OLFJ) in L4/5 unit to induce the spine instability. Then, the change of contralateral LFJ was evaluated by morphological and molecular biological techniques. Results. We showed that the OLFJ induced instability accelerated the cartilage degeneration of the contralateral LFJ. Importantly, the SRμCT elucidated that the three-dimensional structure of the subchondral bone changed in contralateral LFJ, indicated as the abnormity of bone volume/total volume ratio (BV/TV), trabecular pattern factor (Tb. Pf), and the trabecular thickness (Tb. Th). Immunostaining further demonstrated the uncoupled osteoclastic bone resorption, and bone formation in the subchondral bone of contralateral LFJ, indicated as increased activity of osteoclast, osteoblast, and Type H vessels. Conclusion. We develop a novel LFJ OA model demonstrating the effect of abnormal mechanical instability on the degeneration of LFJ. This LFJ degeneration model that highly mimics the clinical conditions is a valuable tool to investigate the LFJ osteoarthritis. Level of Evidence: N/A

Sagittal Alignment With Downward Slope of the Lower Lumbar Motion Segment Influences Its Modes of Failure in Direct Compression: A Mechanical and Microstructural Investigation Study Design. Microstructural investigation of compression-induced herniation of ovine lumbar discs with and without added component of anterior-inferior slope. Objective. Does increased shear arising from a simulated component of motion segment slope imitating sacral slope weaken the lateral annulus and increase risk of overt herniation at this same region. Summary of Background Data. An increase in sacral slope secondary to lordosis and pelvic incidence increases shear stresses at the lumbosacral junction and has been associated with an increase in spondylolisthetic disorders and back injury. The small component of forward shear induced when a segment is compressed in flexion is suggested to cause differential recruitment of the lateral annular fibers leading to its early disruption followed by intra-annular nuclear tracking to the posterolateral/posterior regions. However, the influence of even greater forward shear arising from the added component of slope seen where pelvic incidence and lumbar lordosis are increased in the lower lumbar spine is less understood. Methods. Ovine motion segments were compressed at 40 mm/min up to failure; 9 with a horizontal disc alignment and 26 with a segment slope of 15° and then analyzed structurally. Results. All the horizontal discs failed (11.8 ± 2.4 kN) via vertebral fracture without any evidence of soft tissue failure even in the lateral aspects of the discs. The increased forward shear resulting from the slope decreased the failure load (6.4 ± 1.6 kN). The sloping discs mostly suffered mid-span, noncontinuous disruption of the lateral annulus with some extruding nuclear material directly from these same lateral regions. Conclusion. The increased level of forward shear generated in moderately sloping lumbar segments when compressed was abnormally damaging to the lateral regions of the disc annulus. This is consistent with the view that shear differentially loads the oblique-counter oblique fiber sets in the lateral annulus, increasing its vulnerability to early disruption and overt herniation. Level of Evidence: N/A

Motor and Sensory Impairments of the Lower Extremities After L2 Nerve Root Transection During Total en Bloc Spondylectomy Study Design. Retrospective study. Objective. The purpose of this study was to examine motor and sensory impairments of the lower extremities after L2 nerve root transection during total en bloc spondylectomy (TES) for spinal tumors. Summary of Background Data. At our institute, for TES at L3 to L5 lumbar levels, the nerve roots are preserved. However, at the level of L1 and L2, the vertebral resection and spinal reconstruction via a posterior approach is employed with transection of the nerve roots during dissection and resection of the vertebra. Methods. This study included 13 patients who had undergone TES for spinal tumors involving L2 between 2007 and 2016. Postoperative motor function of the lower extremities was quantified using the Manual Muscle Testing grade for the iliopsoas (IP) and quadriceps femoris (QF) muscles, and a grade of the modified Frankel Classification. Postoperative sensory impairment was quantified by the sites of lower extremity pain and numbness. Results. An initial decrease in strength of the IP and QF muscles in more than 60% of the patients, with a decline in the modified Frankel grade in 76.9%, was observed at 1-week after surgery. All patients recovered by the final follow-up, with 12 of the 13 patients walking without a gait aid. The other patient, who had undergone a bilateral dissection of L3 nerve root during TES of L2 and L3, had a mild QF muscle weakness, requiring a cane for walking. Eleven of 13 patients developed pain or numbness in the groin or thigh area after surgery, with the most common area being the anterior aspect of the thigh. Conclusion. Although IP and QF weakness was observed in the majority of patients who underwent bilateral transection of L2 nerve roots during TES, these deficits recovered over time and did not finally affect activities of daily living. Level of Evidence: 4

Long-Term Follow-Up of Anterior Spinal Fusion for Thoracolumbar/Lumbar Curves in Adolescent Idiopathic Scoliosis Study Design. Retrospective patient series analysis with update of long-term data. Objective. To define the long-term prognosis of the thoracolumbar/lumbar correction after selective anterior spinal fusion (ASF) in adolescent idiopathic scoliosis (AIS). Summary of Background Data. The ASF is a well-described procedure for the treatment of AIS. The correction reliability over time, the consequences in adjacent spinal levels and patient's quality of life are fundamental for the characterization of AIS treatment. Methods. One hundred seven patients were submitted to single-rod ASF for thoracolumbar/lumbar (ThL/L) AIS between 1993 and 2016 in a single-surgeon experience. Seventy five were available for final follow-up evaluation 9 years ±4 (2–23) after surgery. A clinical and sequential radiographic evaluations were performed. Results. The mean age at surgery was 16 years ± 2.33 (14–20) and 94 (87%) were females. The mean final follow-up of the 75 patients available was 9 years ± 4 (2–23). Sixty-five patients had a Lenke type 5C curve and 10 had a type 6C curve. The mean values of the Scoliosis Research Society 22 (SRS-22) questionnaire in Lenke 5C was 92 ± 9 (71–109) and in Lenke 6C 90.3 ± 9 (75–107). In Lenke 5C group, the mean preoperative ThL Cobb angle was 38.4° ± 9.3 (21–60) and the postoperative was 5.9° ± 4.5 (0–18; P < 0.001) being similar at the final follow-up (P > 0.05). In Lenke 6C group, the mean preoperative ThL Cobb angle was 58.6° ± 13.9 (40–90) and the postoperative ThL Cobb was 22.6° ± 14.5 (5–48, P < 0.001) being similar at the final follow-up (P > 0.05). The mean preoperative Thoracic (Th) Cobb angle was 39° ± 7.6 (30–50), the postoperative was 30.6° ± 10.1 (14–49, P < 0.008) and in the final follow-up was 29.3° ± 10.7 (11–48, P < 0.011). Conclusion. ASF is a safe procedure in the treatment of ThL/L with good long-term results and high rates of satisfaction among patients with AIS Lenke type 5C. The partial correction was frequent in Lenke type 6C despite the absence of progression in the non-instrumented curves. Level of Evidence: 4

Development of Deployable Predictive Models for Minimal Clinically Important Difference Achievement Across the Commonly Used Health-related Quality of Life Instruments in Adult Spinal Deformity Surgery Study Design. Retrospective analysis of prospectively-collected, multicenter adult spinal deformity (ASD) databases. Objective. To predict the likelihood of reaching minimum clinically important differences in patient-reported outcomes after ASD surgery. Summary of Background Data. ASD surgeries are costly procedures that do not always provide the desired benefit. In some series only 50% of patients achieve minimum clinically important differences in patient-reported outcomes (PROs). Predictive modeling may be useful in shared-decision making and surgical planning processes. The goal of this study was to model the probability of achieving minimum clinically important differences change in PROs at 1 and 2 years after surgery. Methods. Two prospective observational ASD cohorts were queried. Patients with Scoliosis Research Society-22, Oswestry Disability Index , and Short Form-36 data at preoperative baseline and at 1 and 2 years after surgery were included. Seventy-five variables were used in the training of the models including demographics, baseline PROs, and modifiable surgical parameters. Eight predictive algorithms were trained at four-time horizons: preoperative or postoperative baseline to 1 year and preoperative or postoperative baseline to 2 years. External validation was accomplished via an 80%/20% random split. Five-fold cross validation within the training sample was performed. Precision was measured as the mean average error (MAE) and R2 values. Results. Five hundred seventy patients were included in the analysis. Models with the lowest MAE were selected; R2 values ranged from 20% to 45% and MAE ranged from 8% to 15% depending upon the predicted outcome. Patients with worse preoperative baseline PROs achieved the greatest mean improvements. Surgeon and site were not important components of the models, explaining little variance in the predicted 1- and 2-year PROs. Conclusion. We present an accurate and consistent way of predicting the probability for achieving clinically relevant improvement after ASD surgery in the largest-to-date prospective operative multicenter cohort with 2-year follow-up. This study has significant clinical implications for shared decision making, surgical planning, and postoperative counseling. Level of Evidence: 4

Neurologic Injury in Complex Adult Spinal Deformity Surgery: Staged Multilevel Oblique Lumbar Interbody Fusion (MOLIF) Using Hyperlordotic Tantalum Cages and Posterior Fusion Versus Pedicle Subtraction Osteotomy (PSO) Study Design. A retrospective review of prospectively collected data. Objective. The aim of this study was to determine the safety of MOLIF versus PSO. Summary of Background Data. Complex adult spinal deformity (CASD) represents a challenging cohort of patients. The Scoli-RISK-1 study has shown a 22.18% perioperative risk of neurological injury. Restoration of sagittal parameters is associated with good outcome in ASD. Pedicle subtraction osteotomies (PSO) is an important technique for sagittal balance in ASD but is associated with significant morbidity. The multilevel oblique lumbar interbody fusion (MOLIF) is an extensile approach from L1 to S1. Methods. Single surgeon series from 2007 to 2015. Prospectively collected data. Scoli-RISK-1 criteria were refined to only include stiff or fused spines otherwise requiring a PSO. Roentograms were examined preoperatively and 2 year postoperatively. Primary outcome measure was the motor decline in American Spinal Injury Association (ASIA) at hospital discharge, 6 weeks, 6 months, and 2 years. Demographics, blood loss, operative time, spinopelvic parameters, and spinal cord monitoring (SCM) events. Results. Sixty-eight consecutive patients were included in this study, with 34 patients in each Group. Group 1 (MOLIF) had a mean age 62.9 (45–81) and Group 2 (PSO) had a mean age of 66.76 years (47–79); 64.7% female versus PSO 76.5%; Body Mass Index (BMI) Group 1 (MOLIF) 28.05 and Group 2 (PSO) 27.17. Group 1 (MOLIF) perioperative neurological injury was 2.94% at discharge but resolved by 6 weeks. Group 2 (PSO) had five neurological deficits (14.7%) with no recovery by 2 years. There were four SCM events (SCM). In Group 1 (MOLIF), there was one event (2.94%) versus three events (8.88%) in Group 2 (PSO). Conclusion. Staged MOLIF avoids passing neurological structures or retraction of psoas and lumbar plexus. It is safer than PSO in CASD with stiff or fused spines with a lower perioperative neurological injury profile. MOLIF have less SCM events, blood loss, and number of levels fused. Level of Evidence: 3

Survivals of the Intraoperative Motor-evoked Potentials Response in Pediatric Patients Undergoing Spinal Deformity Correction Surgery: What Are the Neurologic Outcomes of Surgery? Study Design. This is a retrospective cases study from a prospective patient register. Objective. To clarify the clinical implication regard to the survivals of motor-evoked potential (MEP) response. Summary of Background Data. Intraoperative neurophysiological monitoring has become an essential component for decreasing the incidence of neurological deficits during spine surgeries. Significant motor-evoked potential (MEP) loss but does not vanish completely is common especially in some high-risk and complicated pediatric spine deformity surgeries. Methods. A total of 1820 young patients (mean age = 12.2 years) underwent spinal deformity correction were mainly analyzed. Intraoperative monitoring (somatosensory-evoked potential, MEP, free-run electromyography, free-run electromyography) and postoperative neurologic outcomes were mainly analyzed in this study. All patients with monitoring alerts were divided into two groups: group 1, intraoperative MEP recovery group; and group 2, no obvious MEP recovery group. Moreover, the patients would be followed up strictly if he/she showed IOM alerting. The surviving MEP response was identified as significant monitoring alerts (80%–95% MEP Amp. loss) associated with high-risk surgical maneuvers. Results. The results showed that there were 32 pediatric patients (group 1, 21 cases and group 2, 11 cases) presenting significant MEP monitoring alerts (80%–95% loss) relative to baseline. The patients in group 1 presented the partial/entire signal recovery from MEP alerts and they did not show spinal cord deficits postoperation. The patients in group 2 without obvious intraoperative MEP recovery showed different levels of new spinal deficits, no patient showed postoperative complete paraplegia or permanent spinal cord/nerve root deficits. Conclusion. When the intraoperative MEP changes significant and persistent but without totally disappeared, the rate of postoperative neural complication is relatively low. The chance of recovery of these neurological deficits is very high. Therefore, this phenomenon may be used to predictive of nonpermanent paraplegia. Level of Evidence: 3