The Effect of Dexmedetomidine Added to Preemptive Ropivacaine Infiltration on Postoperative Pain After Lumbar Fusion Surgery: A Randomized Controlled Trial
Study Design. A prospective and controlled study of dexmedetomidine added to preemptive ropivacaine infiltration in lumbar fusion surgery. Objective. Assessment of dexmedetomidine added to preemptive ropivacaine infiltration for the relief of postoperative pain after lumbar fusion surgery. Summary of Background Data. Single local anesthetic preemptive wound infiltration for the relief of postoperative pain does not translate into major or consistent clinical benefits after lumbar fusion surgery. Dexmedetomidine added to local anesthetics prolonged the duration of blockade and enhanced the analgesic in peripheral nerve block. The effect of dexmedetomidine added to preemptive ropivacaine infiltration in lumbar fusion surgery for the relief of postoperative pain has yet not been studied. Methods. Fifty-seven patients with elective posterior lumbar fusion were randomly divided into two groups. Five minutes before incision, the skin and subcutaneous tissues were injected with 20 mL 0.5% ropivacaine in group R (n = 28) and 20 mL 0.5% ropivacaine and 1 ug/kg of dexmedetomidine in group RD (n = 29) in two divided doses (i.e., 10 mL per side of the incision line). After the operation, all patients received intravenous morphine for analgesia. The total morphine consumption, the time of first analgesic demand, numbers of PCA analgesia, Visual Analog Scale, and postoperative adverse effects were collected. Results. In group RD, cumulative morphine dose and numbers of PCA analgesia in group RD were significantly reduced, the time of first analgesic demand was significantly delayed compared to the group R. Visual Analog Scale in group RD showed a marked reduction at 8 hours, 12 hours, 16 hours after operation and less patients in group RD experienced postoperative nausea or vomiting compared to the group R. Conclusion. The addition of dexmedetomidine to preemptive ropivacaine wound infiltration provided a superior analgesic effect, reduced postoperative morphine consumption, and prolonged the time of the first analgesic demand with no serious side effects. Level of Evidence: 2

SFKs/p38 Pathway is Involved in Radicular Pain by Promoting Spinal Expression of Pro-Inflammatory Cytokines in a Rat Model of Lumbar Disc Herniation
Study Design. A controlled, randomized, animal study. Objective. The aim of this study was to investigate the role of src-family kinases/p38 pathway in a rat model of lumbar disc herniation (LDH). Summary of Background Data. LDH always generates radicular pain, and the mechanism remains unclear. We have reported that spinal src-family kinases (SFKs) may be involved in the process, but the downstream mechanism needs further investigation. Methods. LDH was induced by implantation of autologous nucleus pulposus (NP), harvest from the tail, in lumbar 4/5 spinal nerve roots of rat. Von Frey filaments and radiant heat tests were performed to determine mechanical and thermal pain threshold respectively. Basso, Beattie, and Bresnahan (BBB) scale was assessed to test the locomotor function. The protein level of p-SFKs, t-SFKs, p-p38, t-p38 in spinal cord was examined by western blotting analysis. Cellular location of p-p38 was determined by immunochemistry staining. Spinal tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, and IL-6 levels were detected by enzyme-linked immunosorbent assay (ELISA). Results. Rats with NP implantation showed persistent ipsilateral mechanical allodynia and thermal hyperalgesia, which manifested as obvious decrease of paw withdrawal threshold (PWT) and paw withdrawal latency (PWL). BBB scale indicated the locomotor function of hindpaws in rats with NP implantation kept intact. Western blotting and immunohistochemistry staining revealed that phosphorylated SFKs (p-SFKs) and phosphorylated p38 MAPK (p-p38) were sequentially upregulated in ipsilateral spinal dorsal horn, but not in contralateral side of rats with NP. Intrathecal delivery of SFKs inhibitor reduced spinal p-p38 expression. Both SFKs and p38 inhibitors alleviated pain behaviors in a dose-responsive manner without disturbing locomotor function and reduced spinal expression of TNF-α, IL-1β, and IL-6 in rats with NP. Conclusion. Spinal SFKs contribute to radicular pain by activation of p38 MAPK and increasing pro-inflammatory cytokines expression in rats with NP implantation. Targeting SFKs/p38 pathway may be helpful for alleviating radicular pain. Level of Evidence: N/A

Comparison of Anterior Cervical Foraminotomy and Posterior Cervical Foraminotomy for Treating Single Level Unilateral Cervical Radiculopathy
Study Design. Retrospective study. Objective. To compare clinical and radiological outcomes after two surgical procedures. Summary of Background Data. Anterior cervical discectomy and fusion is the gold standard treatment for cervical radiculopathy. Cervical foraminotomy is an alternative decompressive treatment option to preserve segmental motion and avoid fusion-related complications. Anterior cervical foraminotomy (ACF) and posterior cervical foraminotmy (PCF) has been introduced to achieve foraminal decompression. The objective of this study was to compare long-term clinical and radiological outcomes after two surgical procedures for the treatment of single-level cervical radiculopathy. Methods. A retrospective review of patients undergoing ACF or PCF for the treatment of single-level unilateral cervical radiculopathy from 2010 to 2012 was performed. Demographic, perioperative, and clinical outcomes of 40 patients for each group were collected from the electronic medical records. Clinical outcomes were assessed by visual analog scores, while disc height (DH), cervical lordosis (CL), and C2–7 sagittal vertical axis (C2–7 SVA) data were obtained from pre- and postoperative radiography data. Results. Both groups showed similar clinical improvements after surgery. Radiographically, the ACF groups showed profound decrease in DH only at the first month after surgery, and there was no significant change in DH after 1 year. The PCF group showed no significant changes in DH at follow-up. With respect to CL, ACF showed a significant decrease. There was no statistically significant change in C2–7 SVA before or after surgery in both groups. Conclusion. Both ACF and PCF showed significant clinical improvement of radiculopathy. In the ACF group, the DH decreased, and CL decreased during the early postoperative period. Radiological parameters were preserved in the PCF group after surgery. However, this group showed greater intraoperative bleeding and revision rates. Care should be taken to manage complications according to the specific surgical treatment. Level of Evidence: 3

Complications Associated With Minimally Invasive Anterior to the Psoas (ATP) Fusion of the Lumbosacral Spine
Study Design. Retrospective cohort study. Objectives. To analyze complications associated with minimally invasive anterolateral retroperitoneal antepsoas lumbosacral fusion (MIS-ATP). Summary of Background Data. MIS-ATP provides anterolateral access to the lumbar spine allowing for safe anterior lumbar interbody fusions between T12-S1. Anecdotally, many surgeons believe that ATP approach is not feasible at L5-S1 level, predisposing to catastrophic vascular injuries. This approach may help overcome limitations associated with conventional straight anterior lumbar interbody fusions, MIS lateral lumbar interbody fusion, and oblique lateral interbody fusion. Methods. A detailed retrospective chart review of patients who had underwent MIS-ATP approach for lumbar fusion between T12-S1 was performed. Available electronic data from surgeries performed between January 2008 and March 2017 was carefully screened for surgical patients treated for spondylolisthesis, spondylosis, stenosis, sagittal, and/or coronal deformity. Detailed review of electronic medical records including operative notes, progress notes, discharge summaries, laboratory results, imaging reports, and clinic visit notes performed by a single independent reviewer not involved in patient care for documented complications. A complication is defined as any adverse event related to the index spine procedure for which patient required specific intervention or treatment. Results. Nine hundred forty patients with a total of 2429 interbody fusion levels performed via MIS-ATP were identified during the study period. Sixty-seven patients (7.2%) sustained one or more complications during the perioperative period, of which 25.5% were surgical and 74.5% were medical. Overall, 78 (8.2%) surgical complications pertaining to the index procedure were noted during a postoperative period of 1 year from the date of surgery. No major vascular or direct visceral injuries were encountered. Conclusions. MIS-ATP approach provides a safe access to anterolateral interbody fusions between T12-S1. The ATP approach is performed by the spine surgeon, does not require neuromonitoring, and warrants minimal to no psoas muscle retraction resulting in significantly reduced postoperative thigh pain and rare neurologic injuries. Additionally, the direct and clear visualization of the retroperitoneal vasculature provided by the ATP approach minimizes the risk of inadvertent vascular injury. Level of Evidence: 4

The Relationship Between Neuropathic Pain and Spinal Alignment: Independent Risk Factors for Low Quality of Life in Middle-Aged and Elderly People
Study Design. Prospective research in middle-aged and elderly people. Objective. To investigate low back pain (LBP) and neuropathic pain (NeP); spinal alignment and range of motion (ROM); spinal degenerative changes in plain radiography; osteoporosis; muscle strength; and physical ability as possible risk factors for poor quality of life (QOL). Summary of Background Data. The aging of society has led to an increase in elderly people with chronic pain, including LBP and NeP. However, there has been no analysis of NeP and spinal sagittal alignment as potential risk factors for decreased QOL in the healthy general population. Methods. The subjects were 1128 people (male 473, female 655, average age: 64.3 yrs) who attended an annual health checkup in Yakumo study. The prevalence of LBP and sciatica were investigated using a visual analogue scale (VAS), and NeP was defined as more than or equal to 13 points on the painDETECT questionnaire. Sagittal spinal alignment with spinal ROM was also measured. Body mass index, muscle strength, physical ability, osteoporosis, and lumbar degenerative changes were measured, and 36-item short-form health survey (SF-36) was used for QOL analysis. Results. NeP was present in 113 people (10%). The NeP (+) subjects had significantly more severe pain, lower gait speed, higher osteoporosis rate, lumbar kyphosis, and larger spinal inclination (P < 0.01) compared with NeP (–) subjects. On SF-36, physical and mental QOL were significantly lower for NeP (+) subjects (P < 0.0001). In multivariate logistic regression analysis adjusted for age and sex, NeP (+) (odds ratio [OR]: 3.01), positive spinal inclination (OR: 1.14), and high VAS for LBP (OR: 1.04) were identified as risk factors for low physical QOL, and NeP (+) (OR: 5.32) was the only significant risk factor for low mental QOL. Conclusion. These results suggest that interventions for NeP and other identified risk factors may contribute to improvement of low physical and mental QOL in middle-aged and elderly people. Level of Evidence: 2

The Impact of Body Mass Index (BMI) on 30-day Outcomes Following Posterior Spinal Fusion in Neuromuscular Scoliosis
Study Design. Retrospective. Objective. Assess the impact of varying severity of BMI on 30-day outcomes following posterior spinal fusions in neuromuscular scoliosis. Summary of Background Data. Obesity in the pediatric population is shown to be associated with adverse outcomes across varying specialties. The weight-outcome relationship in neuromuscular scoliosis has not been thoroughly investigated. Methods. The 2012–2016 American College of Surgeons – National Surgical Quality Improvement (ACS-NSQIP) database was queried using Current Procedural Terminology codes 22800, 22802, and 22804 to identify patients undergoing posterior spinal fusion for neuromuscular scoliosis only. BMI was classified into four groups based on the Center for Disease Control (CDC) BMI-for-age percentile chart – Normal weight (BMI ≥5th to <85th percentile), Underweight (<5th percentile), Overweight (≥85th to <95th percentile) and Obese (≥95th percentile). Multivariate regression models were built to understand the impact of varying BMI severity classes on 30-day outcomes. Results. A total of 1291 patients underwent posterior spinal fusion for neuromuscular scoliosis. A total of 695 (53.8%) were normal weight, 286 (22.2%) were underweight, 145 (11.2%) were overweight, and 165 (12.8%) were obese. Obese patients versus normal weight patients were at a significantly higher risk of surgical site infections (OR 2.15; P = 0.035), wound dehiscence (OR 1.58; P = 0.037), urinary tract infections (OR 3.41; P = 0.010), and 30-day readmissions (OR 1.94; P = 0.029). Of note, overweight versus normal weight individuals had higher odds of cardiopulmonary complications (OR 8.82; P = 0.024). No significant associations were seen for varying BMI and other 30-day outcomes. Conclusions. Obese neuromuscular patients undergoing PSF have higher odds of experiencing adverse outcomes, particularly surgical site infections, urinary tract infections, and readmissions. Providers should promote prevention strategies, such as dietary modification and/or early physical activity in these high-risk patients to minimize the risks of experiencing complications in the acute postoperative period. Level of Evidence: 3

Magnetic Resonance Imaging-Based Morphological Change of Paraspinal Muscles in Girls With Adolescent Idiopathic Scoliosis
Study Design. A cross-sectional study. Objective. To investigate and compare any morphological differences in paraspinal muscles (PSM) between adolescent idiopathic scoliosis (AIS) patients (with severe or non-severe curves) and healthy controls. Summary of Background Data. Several studies have reported abnormalities in biochemical, electromyographic activity, and histological changes of PSM in AIS. However, these studies only had qualitative data and without comparison with controls. Changes of muscle mass and mean density at the lumbar region have been described for scoliotic spines. All these findings suggested that imbalance of PSM in AIS could be a contributing factor to the development of severe scoliotic curve. Methods. T2-weighted MR images with multi-planar reconstruction were acquired in 41 Chinese AIS girls with a primary right-sided thoracic curve and 23 age-matched controls. In AIS, measurements of PSM were taken on both concavity and convexity of scoliosis starting from two vertebrae above and two below the apex. Morphological assessments of the multifidus (MF) and erector spinae (ES) muscles on both sides were made including signal intensity (SI) and fat deposition using manual tracing and thresholding technique, respectively. Same parameters were measured in controls at matched vertebrae. One-way analysis of variance (ANOVA) and Pearson correlation tests were used for statistical analysis. Results. Abnormalities were found at concavity of muscles between AIS and controls. Significantly higher SI and fatty components was observed in AIS at MF muscles on concavity than controls (P-value <0.001). Additionally, SI at MF muscles was significantly correlated with Cobb angle. Conclusion. Increased SI and fatty components are asymmetrically present in PSM at apex in AIS. Our results showed higher intensity in PSM at concavity in AIS when compared with controls. There was a significant linear correlation between abnormal muscle signal and scoliotic curve. Above features are suggestive of altered muscle composition in concave PSM, possibly due to prolonged compression and reduced muscle activity of PSM caused by the spinal deformity. Level of Evidence: 4

Risk, Recovery, and Clinical Impact of Neurological Complications in Adult Spinal Deformity Surgery
Study Design. Multicenter retrospective case series. Objective. To report the risks, recovery, and clinical impact of neurological complications (NCs) in adult spinal deformity (ASD) surgery. Summary of Background Data. Although recent studies have reported the incidence of NCs in ASD surgery, few have addressed the recovery from and clinical impacts of NC. Methods. We reviewed records from a multicenter database for 285 consecutive surgically treated ASD patients who had reached a 2-year follow-up. NCs were categorized as sensory only or motor deficit (MD). Recovery was noted as none, partial, or complete, during hospitalization and at every postoperation visit. Uni- and multivariate risk analyses were performed to identify risk factors for MD. Results. NC developed in 29 (10%) patients within 30 days of surgery, of which 11 were permanent deficits (seven no recovery, and four partial recovery). MD developed in 14 (5%) patients, including one spinal cord injury. Seven MD patients required physical assistance at the latest follow-up. While NC patients experienced significant improvements in health-related quality of life at the 2-year follow-up, the health-related quality of life was significantly worse for the NC versus no-NC group at this time point. Univariate analyses revealed that Schwab-SRS types N and L, pelvic tilt, modified frailty index physical function, and an inferior SRS22 function domain at baseline were risk factors for MD. Among them, modified frailty index physical function, which represented a preoperative decline in activities of daily living, was identified as an independent risk factor for MD (OR: 4.0, 95% CI: 1.2–13.5, P = 0.03). Conclusions. NC developed in 10% of ASD surgery patients, with permanent deficits occurring in 4%. Half of the patients who developed MD required physical assistance, which contributed to the inferior clinical outcomes. Surgical intervention should be considered before severe activities of daily living decline to prevent NCs. Level of Evidence: 4

Predictors of Poor Global Alignment and Proportion Score After Surgery for Adult Spinal Deformity
Study Design. Retrospective observational study of a cohort of consecutive patients. Objective. To determine 1) the correlation between clinical and radiographic outcomes and Global Alignment and Proportion (GAP) score, and 2) which preoperative parameters predominantly influence the risk for poor GAP scores. Summary of Background Data. Although numerous investigators have indicated their criteria for sagittal correction, it is still not unusual to observe poor outcome or complications even after ideal correction. The recently developed GAP score indicates spinopelvic alignment and setting surgical goals according to the score might decrease the prevalence of mechanical complications. However, there is no clear evidence of correlation between the GAP score and clinical outcomes, or which patient factors are preoperative predictors of poor postoperative GAP score. Methods. We included 128 consecutive patients treated with spinal correction surgery who had a minimum 2-year follow-up. The correlations between clinical outcomes, increased proximal junctional angle, and GAP score were determined. Univariate and multivariate logistic regression analyses were conducted to clarify potential preoperative risk factors for poor GAP score. Results. Based on total GAP score, 32 (25%) patients were grouped into proportioned, 50 (39.1%) into moderately disproportioned, and 44 (34.3%) into severely disproportioned spinopelvic alignment. Our present study showed a significantly positive correlation between Oswestry Disability Index, increased proximal junctional angle 2 years after surgery, and total GAP score. Uni and multivariate regression analysis showed a large global tilt was a risk factor for a poor GAP score and that the risk for a poor GAP score increased with ageing. Conclusions. Because GAP score correlated with Oswestry Disability Index and increased proximal junctional angle 2 years after surgery, GAP score might define targets for sagittal spinopelvic alignment for favorable outcomes of corrective spinal surgery. A large preoperative global tilt is a potential predictor of poor postoperative GAP score. Level of Evidence: 3