Spine

"Sailboats in Boothbay, Maine" No abstract available

Mechanical Function of the Nucleus Pulposus of the Intervertebral Disc Under High Rates of Loading Study Design. Bovine motion segments were used to investigate the high-rate compression response of intervertebral discs (IVD) before and after depressurising the nucleus pulposus (NP) by drilling a hole through the cranial endplate into it. Objective. To investigate the effect of depressurising the NP on the force–displacement response, and the energy absorption in IVDs when compressed at high strain rates. Summary of Background Data. The mechanical function of the gelatinous NP located in the center of the IVDs of the spine is unclear. Removal of the NP has been shown to affect the direction of bulge of the inner anulus fibrosus (AF), but at low loading rates removal of the NP pressure does not affect the IVD's stiffness. During sports or injurious events, IVDs are commonly exposed to high loading rates, however, no studies have investigated the mechanical function of the NP at these rates. Methods. Eight bovine motion segments were used to quantify the change in pressure caused by a hole drilled through the cranial endplate into the NP, and eight segments were used to investigate the high-rate response before and after a hole was drilled into the NP. Results. The hole caused a 28.5% drop in the NP pressure. No statistically significant difference was seen in peak force, peak displacement, or energy-absorption of the intact, and depressurized NP groups under impact loading. The IVDs absorbed 72% of the input energy, and there was no rate dependency in the percentage energy absorbed. Conclusion. These results demonstrate that the NP pressure does not affect the transfer of load through, or energy absorbed by, the IVD at high loading rates and the AF, rather than the NP, may play the most important role in transferring load, and absorbing energy at these rates. This should be considered when attempting surgically to restore IVD function. Level of Evidence: N/A

Locally Applied Simvastatin as an Adjunct to Promote Spinal Fusion in Rats Study Design. Basic Science. Objective. To determine if locally delivered simvastatin can enhance bone formation in a rat spinal fusion model. Summary of Background Data. The bone-anabolic properties of statins in fracture healing are well established, however, few studies have evaluated the impact of locally delivered statins in spinal fusion. Methods. We formulated poly(lactic-co-glycolic acid) (PLGA) nanoparticles by adapting previously published techniques. Two types of nanoparticles were created: simvastatin nanoparticles (SimNP) and nanoparticles without simvastatin (BlankNP). Drug elution from SimNP was characterized. Osteoblastic differentiation was analyzed using MC3T3-E1 cells cultured in differentiation medium containing SimNP or BlankNP. Forty male 12 week old outbred Wistar rats underwent uninstrumented posterolateral fusion using iliac crest bone graft and BlankNP, SimNP or simvastatin drug. X-rays to assess bone formation were obtained at 4 weeks and 9 weeks post-operatively. Spines were explanted at 9 weeks for micro-CT analysis, and a blinded manual assessment of fusion (MAF). Results. SimNP achieved a release efficiency of 74.1% with ∼50% release occurring in the first day. Simvastatin and SimNP treated cells showed significantly greater expression of osteopontin (OPN) and osteocalcin (OCN). On micro-CT analysis, SimNP animals had higher bone volume and percent bone volume (bone volume/total volume) than control animals. SimNP rats had higher X-ray scores at 4 weeks (p=0.010) and 9 weeks (p<0.001) relative to BlankNP. MAF showed that SimNP had a higher fusion rate than BlankNP (42.9% vs. 0%, p=0.006). Conclusion. We were able to validate that sustained release of simvastatin via a PLGA nanoparticle. SimNP was able to induce an increase in mineralization as well as an increase in markers of bone formation. X-ray analysis, micro-CT quantification, and MAF assessment of SimNP treated rats showed significantly greater bone formation and fusion mass strength relative to vehicle treated animals. Simvastatin may be a safe, cost-effective bone anabolic agent for use in spinal fusion. Level of Evidence. N/A

AMP-Activated Protein Kinase Activation in Dorsal Root Ganglion Suppresses mTOR/p70S6K Signaling and Alleviates Painful Radiculopathies in Lumbar Disc Herniation Rat Model Study Design. Animal experiment: a rat model of lumbar disc herniation (LDH) induced painful radiculopathies. Objective. To investigate the role and mechanism of AMP-activated protein kinase (AMPK) in dorsal root ganglia (DRG) neurons in LDH-induced painful radiculopathies. Summary of Background Data. Overactivation of multiple pain signals in DRG neurons triggered by LDH is crucial to the development of radicular pain. AMPK is recognized as a cellular energy sensor, as well as a pain sensation modulator, but its function in LDH-induced pain hypersensitivity remains largely unknown. Methods. The LDH rat model was established by autologous nucleus pulposus transplantation into the right lumbar 5 (L5) nerve root. At different time points after AMPK agonist metformin (250 mg/kg/d) or mammalian target of rapamycin (mTOR) inhibitor rapamycin (5 mg/kg) intraperitoneal administration, thermal and mechanical sensitivity were evaluated by measuring paw withdrawal latency (PWL) and 50% paw withdrawal thresholds (PWT). The levels of AMPK, mTOR, and p70S6K phosphorylation were determined by Western blot. We also investigated the proportion of p-AMPK positive neurons in the right L5 DRG neurons using immunofluorescence. Results. LDH evoked persistent thermal hyperalgesia and mechanical allodynia on the ipsilateral paw, as indicated by the decreased PWL and 50% PWT. These pain hypersensitive behaviors were accompanied with significant inhibition of AMPK and activation of mTOR in the associated DRG neurons. Pharmacological activation of AMPK in the DRG neurons not only suppressed mTOR/p70S6K signaling, but also alleviated LDH-induced pain hypersensitive behaviors. Conclusion. We provide a molecular mechanism for the activation of pain signals based on AMPK-mTOR axis, as well as an intervention strategy by targeting AMPK-mTOR axis in LDH-induced painful radiculopathies. Level of Evidence: N/A

ERRFI1 Inhibits Proliferation and Inflammation of Nucleus Pulposus and Is Negatively Regulated by miR-2355-5p in Intervertebral Disc Degeneration Study Design. In vivo and in vitro studies of the role of miR-2355-5p and its possible targets in intervertebral disc degeneration (IVDD). Objective. To elucidate the regulatory role of miR-2355-5p in IVDD and the underlying mechanisms. Summary of Background Data. IVDD, which is caused by multiple factors, is the main cause of lower back pain with or without extremity pain. However, the underlying cellular mechanisms of IVDD pathogenesis are not well elucidated. Cell hyper-proliferation, inflammation, and epidermal growth factor receptor activation have been implicated in IVDD. Up-regulated miR-2355-5p level was identified to associate with IVDD. ERRFI1 (the product of mitogen-inducible gene 6 [MIG6]) was known to inhibit epidermal growth factor receptor activation. Methods. We monitored the expression of miR-2355-5p and ERRFI1 in IVDD tissues and lipopolysaccharides (LPS)-treated nucleus pulposus (NP) cells. We explored the effects of ERFFI1 on NP cells proliferation and LPS-induced pro-inflammatory cytokines production. We searched the targets of miR-2355-5p and explored the effects of miR-2355-5p on NP cells proliferation and cytokines production. Results. We identified the up-regulation of miR-2355-5p and down-regulation of ERFFI1 in IVDD samples and LPS-treated NP cells. ERFFI1 inhibited NP cells proliferation and LPS-induced pro-inflammatory cytokine production. MiR-2355-5p targeted ERFFI1 and negatively regulated ERFFI1 expression. MiR-2355-5p regulated IVDD by targeting ERFFI1. Conclusion. MiR-2355-5p negatively regulated ERFFI1 and prevented the effects of ERRFI1 on inhibiting NP cells proliferation and inflammation. Level of Evidence: N/A

Prevalence and Predictive Factors of Concurrent Cervical Spinal Cord Compression in Adult Spinal Deformity Study Design. Retrospective cross-sectional cohort. Objective. To investigate the prevalence and predictive factors of concurrent cervical spinal cord compression (CSCC) in patients with adult spinal deformity (ASD). Summary of Background Data. In patients with ASD undergoing major thoracolumbar realignment surgery, concurrent CSCC potentially increases the risk of progression of myelopathy or cervical cord injury due to various perioperative factors including poor intraoperative neck positioning and hypotension. However, the prevalence of CSCC in ASD patients has not been previously studied. Methods. This study included ASD patients who were indicated for major thoracolumbar corrective surgery (>5 levels). The presence of CSCC was determined using the modified Cord Compression Index (Grades 0–3) based on the cervical magnetic resonance imaging (MRI). Significant CSCC was defined as Grade>2, and the distribution of compression level as well as the number of Grade>2 segments were investigated in each patient. A multivariate regression analysis was performed to identify the predictors of CSCC with variables being the patients' characteristics including radiographic sagittal alignment parameters. Results. Of 121 patients with ASD, 41 patients (33.8%) demonstrated significant CSCC on MRI. Intramedullary T2 hyper-intensity (myelomalacia) was present in eight patients (6.6%). Thirty-five of 41 patients were asymptomatic or with myelopathy that is difficult to detect. Significant CSCC was most commonly observed at C4/5 level. Four patients (3.3%) underwent cervical decompression and fusion prior to thoracolumbar reconstruction. Multivariate regression analysis revealed old age, increased body mass index (BMI), and PI-LL mismatch independently predicted the CSCC grade. Conclusion. The prevalence of concurrent significant cervical cord compression in patients with ASD is relatively high at 33.8%. Preoperative evaluation of cervical MRI and examinations for signs/symptoms of myelopathy are essential for patients with (1) older age, (2) increased BMI, and (3) high PI-LL mismatch to avoid progressive myelopathy or cord injury during ASD surgery. Level of Evidence: 4

Sagittal Alignment Outcomes in Lordotic Cervical Spine: Does Three-Level Anterior Cervical Discectomy and Fusion Outperform Laminoplasty? Study Design. A prospective cohort study. Objective. To compare the radiological outcomes between three-level anterior cervical discectomy and fusion (ACDF) and plate-only open-door laminoplasty (LAMP) in patients with lordotic cervical spine. Summary of Background Data. Both three-level ACDF and LAMP are important surgical methods for multilevel cervical spondylotic myelopathy, but the cervical sagittal alignment outcomes and the lordosis preserving abilities between the two specific approaches have not been carefully compared. Methods. Sixty patients, all of whom had lordotic cervical spines and underwent three-level ACDF (n = 22) or LAMP (n = 38) for the treatment of multilevel cervical spondylotic myelopathy, were prospectively studied. Upright neutral cervical lateral radiographs were assessed preoperatively, at 3 days after surgery, and at the last follow-up (1.5 years). The primary radiological outcomes are C2–7 Cobb angle, and the secondary outcomes include C2–7 sagittal vertical axis , disc height, Harrison angle, and Ishihara index. The relationship between preoperative parameters and follow-up outcomes were assessed. Results. Preoperative cervical sagittal alignment parameters were similar between the two groups. Patients in the ACDF group obtained larger C2–7 Cobb angles than those the LAMP group early after surgery. However, the lordosis in the ACDF group decreased significantly during follow-up, leading to similar outcomes between the two groups. The lordosis-preserving ability of ACDF is significantly poorer than that of LAMP. Secondary radiological parameters also showed similar trends. In both groups, the preoperated Ishihara index was significantly related to follow-up C2–7 Cobb angles. For patients with Ishihara index less than 20, ACDF is more likely to produce a larger C2–7 Cobb angled at the time of follow-up. Conclusion. In patients with lordotic cervical spine, the sagittal alignment outcomes of the two approaches were similar, and the lordosis-preserving ability was poorer in ACDF. Further research should focus on the factors related to the lordosis-preserving ability of multilevel ACDF. Level of Evidence: 3

Pain Intensity and Fear Avoidance Explain Disability Related to Chronic Low Back Pain in a Saudi Arabian Population Study Design. A cross-sectional study. Objective. The aim of this study was to describe multi-dimensional profiles for people with chronic low back pain (CLBP) and to examine the associations between CLBP-related disability and individual, psychosocial and physical factors in a Saudi population. Summary of Background Data. CLBP-related disability is a multidimensional phenomenon. There is growing interest in exploring factors associated with CLBP-related disability in Saudi Arabia but research is limited in comparison to other countries. Methods. Participants completed questionnaires covering demographics, pain intensity, back beliefs, fear avoidance, psychological distress, and physical activity. Oswestry Disability Index (ODI) was used to measure disability. Participants also performed a standardized sequence of physical performance tests and a Pain Behavior Scale was used to evaluate pain behaviors during performance of these tests. The relationships between disability and all variables were explored using univariate and multivariate regression analyses. Results. One hundred and fifteen participants were included, 63% of whom were female. Participants demonstrated moderate disability (mean [SD]: 26.6 [13.5]). The mean (SD) back beliefs score was 28.6 (7.3). Mean depression, anxiety, and stress (DASS 21) scores indicated mild distress; however, 26% to 39% scored in the moderate to severe range for at least one subscale. In univariate analyses, pain intensity and fear avoidance beliefs (physical activity and work) were moderately associated with disability (r = 0.56, 0.49, 0.52, respectively, P < 0.001), with all other factors demonstrating weak association. Multivariate regression revealed that pain intensity, fear avoidance beliefs, psychological distress, and participants' age were all found to be associated with disability, accounting for 52.9% (adjusted R2 = 0.529) of variability. Conclusion. This study provides a unique insight into the clinical profile of people with CLBP in a Saudi Arabian population. Pain and psychosocial factors were significantly associated with disability. This study supports the contention that CLBP-related disability is a multifactorial biopsychosocial condition across different cultures. Level of Evidence: 3

Scoliosis and Cardiopulmonary Outcomes in Osteogenesis Imperfecta Patients Study Design. Retrospective clinical study of individuals with osteogenesis imperfecta (OI). Objective. To assess the relationship between severity of scoliosis and pulmonary function, and to assess the relationship between restrictive lung disease and self-reported quality of life in individuals with OI. Summary of Background Data. OI is a heritable connective tissue disorder characterized by osteopenia and a predisposition to fracture. Respiratory insufficiency is a leading cause of mortality. Literature on pulmonary function in this population has shown a negative correlation between percent-predicted vital capacity and severity of scoliosis. However, it has been suggested that decreased pulmonary function in OI may be due to intrinsic pulmonary disease, in addition to the impact of vertebral compression fractures and scoliosis. Methods. Anterior-posterior spine radiographs and pulmonary function tests from 30 individuals with OI were reviewed. Radiographs were evaluated for scoliosis, defined as a curve ≥ 10°. If more than one curve was present, the largest curve was used. Pulmonary function was defined as the forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio. Restrictive pulmonary disease was defined as FEV1/FVC > 80%, while obstructive disease was defined as FEV1/FVC < 70%. Bivariate correlation analysis was performed, using Spearman rho correlation coefficient (P < 0.05). Quality of life was assessed by SF-36. Results. The mean age was 27.6 years (range: 12–42 yrs). 57.6% were female. OI type IV was the most common (46.7%), followed by OI type III (33.3%), OI type I (10%), OI type IX (6.67% each), and OI type VIII (3.33%). Pulmonary comorbidity was present in 40% of individuals, while 6.67% had a cardiac comorbidity. The correlation between scoliosis and pulmonary function was weak and not significant (R = −0.059, P = 0.747). Conclusion. Pulmonary function is not significantly correlated with scoliosis, supporting the hypothesis that decreased pulmonary function is intrinsic to OI and/or chest wall deformities, rather than secondary to scoliosis. Level of Evidence: 4

The Change in Sway and Neuromuscular Activity in Adult Degenerative Scoliosis Patients Pre and Post Surgery Compared With Controls Study Design. Prospective cohort study. Objective. The purpose of this study is to quantify the extent of change in sway associated with maintaining a balanced posture within the cone of economy (CoE), in a group of adult degenerative scoliosis (ADS) patients' pre and postsurgery and compare them to matched non-scoliotic controls. Summary of Background Data. Patients with spinal deformities adopt a variety of postural changes in the spine, pelvis, and lower extremities in their effort to compensate for the anterior shift in the gravity line. ADS patients are known to exhibit an increased sway within their CoE. Greater sway expends more energy while standing when compared with healthy controls. Spinal alignment surgery has been shown to improve sagittal vertical axis and balance. Methods. Thirty-three ADS patients and performed a series of functional balance tests a week before and 3 months after surgery along with 20 non-scoliotic control. Results. ADS patients demonstrated more initial CoM (P = 0.001) and head (P = 0.011) displacements. Postoperatively ADS patients exhibited less CoM sway (P = 0.043) and head sway (P = 0.050), in comparison to their presurgery measures. Postsurgical ADS patients demonstrated more CoM (P = 0.002) and head (P = 0.012) displacements and increased muscle activity in comparison to non-scoliotic controls. Conclusion. Surgical alignment reduced the amount of sway, reduced the center of mass displacement, and reduced spine and lower extremity energy expenditure in ADS' patients. In symptomatic preoperative ADS patients, sagittal sway increased along with greater lumbar spine and lower extremity neuromuscular activity in comparison to a non-scoliotic control. Although surgical alignment improved ADS functional parameters during a dynamic balance test, these parameters approached but did not fully achieve non-scoliotic control parameters when measured 3 months after surgery. Level of Evidence: 3

Alexandros Sfakianakis
Anapafseos 5 . Agios Nikolaos
Crete.Greece.72100
2841026182

6948891480

alsfakia@gmail.com