MRI-based lesion quality score assessing ossification of the posterior longitudinal ligament of the cervical spine.

BACKGROUND CONTEXT: No method currently exists for MRI-based determination of ossification of the posterior longitudinal ligament (OPLL) of the cervical spine using objective criteria. PURPOSE: The purpose of this study was to develop an MRI-based score to determine whether a lesion represents a cervical OPLL lesion and to establish the objective diagnostic value. STUDY DESIGN: Retrospective cohort in a single medical institution. PATIENT SAMPLE: Thirty-five patients undergoing surgery for OPLL (Group A) and 99 patients undergoing cervical disc arthroplasty for soft disc herniation (Group B) between 2011 and 2020 were retrospectively included. All OPLL lesions on unenhanced MRI scan were correlated with a corresponding CT scan. Demographics were comparable between the two groups. OUTCOME MEASURES (PHYSIOLOGIC MEASURES): Using unenhanced magnetic resonance imaging (MRI), the T1- and T2- lesion quality (LQ) scores were calculated. Receiver operating characteristic (ROC) analysis was performed to calculate the area-under-the-curve (AUC) of both LQ scores as a predictor of the presence of OPLL. Computed tomography (CT)-based Hounsfield unit (HU) values of OPLL lesions were obtained and compared with both LQ scores. The LQ scores for MRI scanners from different manufacturers were compared using Student's t test to confirm the validity of the LQ score by scanner type. METHODS: The regions of interest for signal intensity (SI) were defined as the darkest site of the lesion and the cerebrospinal fluid (CSF) at the cerebellomedullary cistern. The T1 and T2 LQ scores were measured as the ratio of the SI at the darkest site of the lesion divided by the SI of the CSF. RESULTS: The T1 and T2 LQ scores in Group A were significantly lower than those in Group B (p<.001). ROC analysis determined that T1 and T2 LQ scores of 0.46 and 0.07, respectively, could distinguish the presence of OPLL with an accuracy of 0.93 and 0.89, respectively (p<.001). When the T1 LQ score of the lesion is <0.46, a diagnosis of OPLL may be suspected with 100% sensitivity and 92.3% specificity. The HU of the lesion had a moderate negative correlation with the T1 LQ score (r=-0.665, p<.0001). Both LQ scores were unaffected by manufacturer type. CONCLUSIONS: This study found a correlation between the MRI-based T1 LQ scores and CT-based HU value for identifying OPLL lesions. Additional studies will be needed to validate that the T1 LQ score from the unenhanced MRI scan can identify cervical OPLL.

Preoperative planning of compact zone trajectory is necessary in treating osteoporotic vertebral compression fracture with endplate involvement: A prospective randomized controlled study.

BACKGROUND: This prospective randomized controlled study compares the clinical and radiological outcomes between reduction methods with or without compact trabecular bone during percutaneous kyphoplasty in osteoporotic vertebral fractures. METHODS: The cohort of 100 patients who underwent percutaneous kyphoplasty was randomly divided into group A (guide pin and balloon introduced directly into fracture site) and group B (guide pin and balloon inserted away fracture site). The surgery duration, clinical and radiological outcomes postoperatively and at follow-up, and complications of cement leakage and adjacent fracture were recorded. Patients were followed up for an average of 20.18 months. The clinical outcomes were assessed using the Oswestry Disability Index and visual analog scale. RESULTS: The two groups had similar patient demographics, surgery times, and volume of cement injected. The method using elevation of the collapsed endplate indirectly had no significant influence on radiological outcomes but significantly decreased the occurrence of intradiscal cement leakage and improved 1- and 12-month postoperative functional outcomes. CONCLUSION: Elevating and reinforcing the collapsed endplate rather than just filling the defect during percutaneous kyphoplasty is safe and effective. This technique decreased pain and improved function with lower rates of further collapse of the osteoporotic vertebrae compared to defect-filling alone.

Reducing surgical site infections after spine surgery: the optimal amount of normal saline for intra-wound irrigation.

BACKGROUND CONTEXT: Surgical site infection (SSI) following lumbar surgery can increase healthcare costs and lead to poor clinical outcome. Irrigation of wounds with saline solution is widely accepted globally and safe for nearly all kinds of surgery. However, the efficacy of different volumes of wound irrigation has not been addressed in elective spine surgery. The role and the optimal amount of intraoperative wound saline irrigation in preventing SSI in clean spinal surgery remain unclear. PURPOSE: We aimed to investigate if insufficient intraoperative irrigation may be a risk factor for postoperative SSI. Additionally, we investigated the optimal amount of normal saline (NS) for irrigation to prevent postoperative SSI. STUDY DESIGN: This is a retrospective study of patients with degenerative spinal stenosis who were treated surgically. Patients were grouped according to the amount of intra-wound irrigation during surgery. PATIENT SAMPLE: We included 444 patients with degenerative lumbar spinal conditions who had undergone one to five level open spinal fusion surgeries from January 2015 through April 2020. OUTCOME MEASURES: The definition of superficial or deep SSI in this study was based on the Centers for Disease Control and Prevention criteria for SSI. The fusion status accessed was based on the Bridwell grading system at the final follow-up. Self-reported and clinical outcome measures include visual analog scale and Oswestry Disability Index. METHODS: A total of 193 patients underwent irrigation with a bulb syringe with manual method (B group) with 2,000 mL NS; 251 patients underwent interpulse battery-powered device irrigation (P group) with >6,000 mL NS. Based on our protocolized departmental guidelines, all patients received the same preoperative preparation and standard surgical steps and postoperative care plan. Patients' demographic and surgical parameters were recorded. The main outcome measures included superficial wound infection, deep infection and overall infection. RESULTS: The incidence of overall SSI was 4.66% in the B group and 1.59% in the P group. The univariate analysis revealed a significant correlation with DM and irrigation amount per hour during surgery but not age, BMI, smoking, operative duration, fusion level, or blood loss. We determined the optimal irrigation amount during surgery as 1,400 mL per hour based on the receiver operating characteristic (ROC) curve (sensitivity, 92.3%; specificity, 44.1%). This was statistically significant (p=.033) with an odds ratio of 9.284 (95% confidence interval 1.2-72.0). In the analysis of surgical factors, the infection group had a significantly lower irrigation amount during surgery. To summarize, patients with diabetes and those receiving less than 1,400 mL of NS/hour had a higher likelihood of developing SSI. CONCLUSIONS: We observed that diabetes and lower volume of intraoperative irrigation were both risk factors for postoperative SSI following degenerative lumbar spine surgery. To reduce SSI in lumbar spine surgery, intra-wound irrigation with more than 1,400 mL/h of NS was recommended.

Posterior instrumentation for osteoporotic fractures in the thoracic or lumbar spine: Cement-augmented pedicle screws vs hybrid constructs.

BACKGROUND: Cement-augmented pedicle screws (CPS) and hybrid construct (HC), consisting of pedicle screws and additional hooks, are common fixation methods for osteoporotic spine fracture. No study has compared surgical results of CPS and HC for treating osteoporotic spine fracture. The aim of the study was to compare surgical results using CPS or HC for osteoporotic fractures of the thoracic or lumbar spine. METHODS: This retrospective cohort study included 84 patients who received surgical treatment with CPS (n = 43) or HC (n = 41) for osteoporotic spine fractures from January 2011 to December 2015, with a mean follow-up of 67 months. Sixty-five patients with neurological deficits received long posterior instrumentation, short posterior decompression, and posterolateral fusion. The 19 patients without neurologic deficits received long posterior instrumentation without posterior decompression and fusion. Radiographic, clinical, and neurologic outcomes were evaluated. RESULTS: The HC group had significantly shorter operative times (231 vs 258 minutes), greater blood loss (497 vs 427 mL), better immediate postoperative kyphosis reduction (10.6° vs 9.1°), and greater final reduction loss (9.8° vs 7.1°) than the CPS group. In both groups, significant loss of the kyphotic angle was apparent during follow-up. Improved ambulation after surgery occurred in 51.2% and 58.5% of patients in the CPS and HC groups, respectively. Neurologic function after surgery improved 0.5 and 0.7 grades in the CPS and HC groups, respectively. Implants failed in 2.3% and 2.4% of patients in the CPS and HC groups, respectively. The incidence of cement leakage from screw augmentation was 38.9%. CONCLUSION: The CPS and HC techniques for treating osteoporotic fractures of the thoracic or lumbar spine did not differ statistically in terms of improved radiologic and clinical outcomes, final neurologic and ambulatory function, or implant failure rates, making them equally comparable alternatives.

Investigation of preoperative asymptomatic bacteriuria as a risk factor for postvertebroplasty infection.

BACKGROUND: Postvertebroplasty infection (PVI) is a catastrophic complication after vertebroplasty (VP). Although the urinary tract has been considered as a source of infectious pathogens, whether asymptomatic bacteriuria (ASB) is a risk factors for PVI remains unknown. METHODS: This retrospective study included 716 patients (207 males; 509 females) treated with VP for osteoporotic vertebral fractures in a single medical center between May 2015 and December 2019. Clinical symptoms, urinalysis results, and culture data were collected preoperatively to identify patients with ASB. The primary outcome was PVI at the index level during follow-up. Demographic data and laboratory test results were compared between the PVI and non-PVI groups. RESULTS: The mean age of the cohort was 78.6 ± 9.6 (range, 63-106). The prevalence of ASB was 14.1%, with female predominance (63.4%). The overall PVI rate was 1.26% (9/716). The PVI group had more patients with ASB (4/9, 44.4%) than did the non-PVI group (97/707, 13.7%) (p = 0.027). The rate of ASB treatment was similar between the PVI and non-PVI groups (25% vs. 23.7%, respectively). No case of PVI was caused by the urine culture pathogen. Multivariate analysis identified the following risk factors for PVI: ASB (odds ratio [OR], 5.61; 95% CI, 1.14-27.66; p = 0.034), smoking (OR, 16.26; 95% CI, 2.58-102.65; p = 0.003), and malignancy (OR 7.27; 95% CI, 1.31-40.31; p = 0.023). CONCLUSION: ASB was not uncommon among patients admitted for VP and should be considered a marker of relatively poor host immunity. Preoperative ASB, a history of malignancy, and smoking were identified as significant risk factors for PVI.

Superior facet joint violation between open and minimally invasive techniques in lumbar fusion surgery: An updated systematic review and meta-analysis.

BACKGROUND: Superior facet joint violation (FJV) is a potential risk factor for adjacent segment disease following lumbar fusion surgery. We sought to conduct a systematic review and meta-analysis to compare screw-related superior FJV rates between the open and different minimally invasive (MI) techniques-fluoroscopy-based, 3D-image navigation, and navigation with robotic assistance-in adult lumbar fusion surgery. METHODS: We searched original articles comparing the rates of screw-related FJV between the open and different MI techniques in adult lumbar fusion surgery for lumbar degenerative diseases in PubMed, EMBASE, and the Cochrane Library from inception to September 2021. We compared the numbers of top-level pedicle screws and associated superior FJVs in the main analyses and performed subgroup analysis based on different MI techniques to examine whether individual MI approaches differed in superior FJV rate. Risk ratio (RR) and 95% confidence interval (CI) were calculated in a random-effect meta-analysis. RESULTS: Included in the meta-analysis were 16 articles with 2655 patients and 4638 top-level pedicle screws. The pooled analysis showed no significant difference in superior FJV rates between the MI and open groups (RR: 0.89, 95% CI: 0.62-1.28). The subgroup analysis demonstrated that the overall rates of superior FJV were 27.1% (411/1518) for fluoroscopy-based, 7.1% (43/603) for 3D-image navigation, and 3.2% (7/216) for navigation with robotic assistance. Compared with the open method, the overall RRs were 1.53 (95% CI: 1.19-1.96) for fluoroscopy-based, 0.41 (95% CI: 0.22-0.75) for 3D-image navigation, and 0.25 (95% CI: 0.08-0.72) for navigation with robotic assistance. CONCLUSION: Among the three common MI techniques, fluoroscopy-based can be associated with a higher risk of superior FJV, while both 3D-image navigation and navigation with robotic assistance may be associated with lower risks as compared with the open method. Considering the limitations of the study, more trials are needed to prove these clinical findings.

Does local vancomycin powder impregnated with autogenous bone graft and bone substitute decrease the risk of deep surgical site infection in degenerative lumbar spine fusion surgery?-An ambispective study.

BACKGROUND: Deep surgical site infection (DSSI) is one of the most challenging complications in lumbar fusion surgery. Few investigations examined the effect of vancomycin powder mixed with autogenic bone graft (ABG) and bone substitutes on preventing DSSI in degenerative lumbar fusion surgeries as well as any interference with bony fusion. The aim of the study was to investigate the effects of ABG along with bone substitutes as a local vancomycin delivery system on preventing DSSI in lumbar instrumented fusion and compared with those who did not use vancomycin powder. METHODS: From January, 2015 through December, 2015, a one-year prospective study using vancomycin powder mixed with ABG and bone substitute for degenerative lumbar fusion surgeries as vancomycin (V) group, 1 gm vancomycin for 2 and 3-level, and 2 gm for more than 3-level instrumentation. From December, 2013 through December 2014, patients received degenerative lumbar fusion surgeries without using vancomycin before the vancomycin protocol were retrospectively enrolled as non-vancomycin (NV) group. Vancomycin concentration was checked at post-operative days 1 and 3 for both the serum and drainage. Patients' demographic data, microbiology reports, fusion status and functional outcomes were evaluated. RESULTS: One hundred and ten patients were enrolled prospectively in the V group, and 86 for the NV group. After an average 41 months follow-up (range, 36-54), 3 patients (3.48%) developed postoperative DSSIs in the NV group, thereby requiring revision surgeries and parenteral antibiotics treatment versus no DSSIs (0%, 0/100) in the V group. (p = 0.048). The postoperative serum vancomycin levels were undetectable and no vancomycin related side effects was encountered. The mean vancomycin concentration of drainage at postoperative days 1 and 3 were 517.96 ± 174.4 and 220.14 ± 102.3 µg/mL, respectively. At final follow-up, there was no statistical difference observed in terms of clinical and radiologic outcomes. CONCLUSIONS: Our vancomycin protocol may reduce the incidence of DSSI in degenerative lumbar fusion surgery without affecting bony fusion. LEVEL OF EVIDENCE: Level III ambispective comparative study.

Risk Factors for Postsurgical Gout Flares after Thoracolumbar Spine Surgeries.

Gouty arthritis is the most common form of inflammatory arthritis and flares frequently after surgeries. Such flares impede early patient mobilization and lengthen hospital stays; however, little has been reported on gout flares after spinal procedures. This study reviewed a database of 6439 adult patients who underwent thoracolumbar spine surgery between January 2009 and June 2021, and 128 patients who had a history of gouty arthritis were included. Baseline characteristics and operative details were compared between the flare-up and no-flare groups. Multivariate logistic regression was used to analyze predictors and construct a predictive model of postoperative flares. This model was validated using a receiver operating characteristic (ROC) curve analysis. Fifty-six patients (43.8%) had postsurgical gout flares. Multivariate analysis identified gout medication use (odds ratio [OR], 0.32; 95% confidence interval [CI], 0.14−0.75; p = 0.009), smoking (OR, 3.23; 95% CI, 1.34−7.80; p = 0.009), preoperative hemoglobin level (OR, 0.68; 95% CI, 0.53−0.87; p = 0.002), and hemoglobin drop (OR, 1.93; 95% CI, 1.25−2.96; p = 0.003) as predictors for postsurgical flare. The area under the ROC curve was 0.801 (95% CI, 0.717−0.877; p < 0.001). The optimal cut-off point of probability greater than 0.453 predicted gout flare with a sensitivity of 76.8% and specificity of 73.2%. The prediction model may help identify patients at an increased risk of gout flare.

Efficacy of Povidone Iodine Solution in the Prevention of Surgical Site Infections in Minimally Invasive Instrumented Spinal Fusion Surgery.

STUDY DESIGN: A retrospective case-controlled study. OBJECTIVES: To evaluate overall infection rate and adverse event after harvesting bone graft soaking and surgical wound irrigation by povidone iodine solution (PVI) in the minimally invasive instrumented spinal fusion surgery. In order to reduce the rate of surgical site infection in spinal surgery, surgical wound irrigation by povidone iodine solution has been well-established. However, the efficacy of autologous bone graft soaking by PVI has not been evaluated before. METHODS: This is a retrospective cohort study. 120 patients were enrolled in the PVI group and compared with 124 patients in the historical cohort. In the PVI group, the harvesting autologous bone graft was soaking and the surgical wound was also irrigated by diluted PVI solution. The outcome measures were overall infection rate, superficial wound infection and deep infection. In addition, the delayed union of the fusion mass was also evaluated through the radiograph evaluation. RESULTS: Both groups shared similar patient demographics instead of body mass index. The use of PVI solution had decreased the overall infection rate (0% versus 4.03%, p = 0.026) and deep infection rate (0% versus 3.23%, p = 0.047). In addition, there was no delayed bone healing in the PVI group after autologous bone graft soaking. CONCLUSIONS: In this study, we conclude that harvested autologous bone graft after PVI soaking in spinal fusion surgery can decrease the incidence of deep infection.

Classification and citation analysis of the 100 top-cited articles on adult spinal deformity since 2011: A bibliometric analysis.

BACKGROUND: Studies of the 100 most-cited articles are reported for many subjects. However, none has analyzed the article characteristics associated with high citation frequency. This study aims to (1) graphically depict characteristics of the 100 top-cited articles addressing adult spinal deformity (ASD), (2) diagram the association between articles according to subject and major topic medical subject headings (MeSHs), and (3) investigate whether major topic MeSH correlates with article citation frequency. METHODS: The 100 top-cited ASD publications since 2011 were retrieved using a PubMed Central search on May 6, 2020. Using titles and abstracts, eight subject categories were identified: surgery, conservative treatment, normal values in spinopelvic alignment, review, cervical alignment, classification, compensatory mechanism, and spine-hip relationship. Sankey diagrams were used to organize the information. Network analysis was performed according to article subject and major topic MeSHs. Pearson's r was used to determine whether the weighted number of citations correlates with major topic MeSHs and the number of citations. RESULTS: The average number of citations per article was 34.8 (range, 19-156). The most represented country was USA (n = 51). The most productive and highly cited journal was Spine (Phila Pa 1976) (n = 34; average, 38.2 citations per article). The most frequent subject categories and major topic MeSHs were "surgery" (n = 53) and "scoliosis" (weighted count, 9.8), while articles with the subject "compensatory" had the highest average number of citations (64.7). The most highly cited article, by Dr. F. Schwab in 2012, had 156 citations. Network analysis revealed the relationships between these articles according to major topic MeSHs. The weighted number of citations according to major topic MeSHs correlated significantly with article citation frequency (Pearson's r, 0.57; p < 0.001). CONCLUSION: Multiple characteristics of the 100 top-cited ASD articles are presented in diagrams to guide evidence-based clinical decision-making in ASD.

Postoperative spinal orthosis may not be necessary for minimally invasive lumbar spine fusion surgery: a prospective randomized controlled trial.

BACKGROUND: With the progress and success in minimally invasive surgery of transforaminal lumbar interbody fusion (MIS TLIF), the musculoskeletal injury was minimized. However, the role of postoperative orthosis in MIS TLIF has not been established and there is little evidence supporting the routine use of orthosis in MIS TLIF. METHODS: This is a prospective randomized clinical study. 90 patients who underwent MIS TLIF were randomly divided into groups A (with postoperative spinal orthosis) and B (without postoperative spinal orthosis). Patients were followed up for an average of 12.6 months. Clinical outcome was assessed using the Oswestry disability index (ODI) and visual analogue scale (VAS). Fusion rate was classified with the BSF scale system at postoperative 6-month, and 12-month. RESULTS: Both groups had similar patient demographics. The use of postoperative spinal orthosis had no significant influence on instrumentation-related complications or radiological parameters at each follow-up. CONCLUSIONS: In this study, we conclude that postoperative spinal orthosis is not necessary for MIS TLIF. Patients without postoperative spinal orthosis had the same fusion rates and improvement of VAS and ODI scores.

Preoperative facet joint arthropathy does not impact long-term clinical outcomes after lumbar-stability-preserving decompression and dynesys fixation.

To evaluate the impact of the preoperative severity of facet joint arthropathy on long-term functional outcomes and spinopelvic parameters in patients undergoing lumbar-stability-preserving decompression and Dynesys fixation. In this retrospective study, 88 patients undergoing combined surgery at our hospital from 2008 to 2015 were included. The patients were divided into two groups, the less and more than mean degeneration groups, based on preoperative facet joint arthropathy of the index level(s). The clinical outcomes were the Visual Analogue Scale (VAS) score, the Oswestry Disability Index (ODI) score and spinopelvic parameters. The mean follow-up durations for the less and more than mean degeneration groups were 84.83 ± 27.58 and 92.83 ± 20.45 months, respectively. The combined surgery significantly improved VAS and ODI scores, and increased sacral slope (SS) regardless of preoperative arthropathy severity. In addition, facet joint arthropathy at adjacent levels continued to worsen after surgery in both arthropathy severity groups. Preoperative facet joint arthropathy did not influence most long-term clinical outcomes in patients undergoing lumbar-stability-preserving decompression and Dynesys fixation. This combined surgery may be suitable for patients with facet joint arthropathy regardless of disease severity.

Incidences and Risk factors of Screw-related Superior Facet Articular Surface Violation at L4 and L5 levels in Transforaminal Lumbar Interbody Fusion: Open Surgery Versus Minimally Invasive Techniques.

STUDY DESIGN: A retrospective comparative study with radiographic measurements. OBJECTIVE: The aim of this study was to investigate incidences and risk factors of screw-related superior facet articular surface violation (FASV) and optimal pedicle screw angles (PSAs) to avoid FASV at L4 and L5 levels in transforaminal lumbar interbody fusion (TLIF) with either open surgery (OS) or minimal invasive (MIS) techniques with 3D C-arm navigation. SUMMARY OF BACKGROUND DATA: L4 to S1 are common levels in TLIF. Adjacent segment diseases (ASD) following TLIF is not uncommon. Screw-related FASV at the superior level is one of the potential risk factors for ASD. METHODS: In the OS and MIS groups, 111 and 110 screws were included at L4 level, and 114 and 110 screws at L5 level, respectively. Postoperative computed tomography examined screw-related FASV at L3-4 and L4-5 facet levels. The entry point was the location where pedicle screws placed into the facet joints. RESULTS: The OS technique and insertion at the L5 level increased the likelihood of FASV 2.56 and 1.81 times, respec-tively. Multivariate logistic regressions analysis determined PSA was a significant factor associated with FASV. Pearson r between PSA and the distance between midline and entry point was 0.905 (P < .0001). Adding one degree of convergence in PSA led to a mean 0.87 lower odds of an FASV event, regardless of surgical techniques. In 90% of patients in the OS and MIS groups, PSA with FASV was < 11.9° and <15.9° at L4 level, and <15.9° and <21.8° at L5 level, respectively. CONCLUSION: PSAs played an important role in FASV. MIS allowed greater PSAs and resulted in fewer incidences of FASV. To avoid FASV in 90% of patients, the PSAs might be at least 11.9° and 15.9° at L4 level, and 15.9° and 21.8° at L5 level for OS and MIS techniques, respectively.Level of Evidence: 3.

Risk factors for residual neurologic deficits after surgical treatment for epidural abscess in the thoracic or lumbar spine.

BACKGROUND CONTEXT: Spinal epidural abscess (SEA) can cause neurologic deficits and needs urgent surgical intervention. Many clinical factors had been proposed to predict surgical outcomes in patients with SEA, but the predictive radiographic risk factors for residual neurologic deficits were not addressed sufficiently. PURPOSE: To analyze the clinical and radiographic risk factors for residual neurologic deficit in patients with SEA after surgical intervention of the thoracic or lumbar spine. STUDY DESIGN/SETTING: A retrospective consecutive case series. PATIENT SAMPLE: From January 2005 through December 2014, 53 patients with primary SEA, confirmed by culture or histopathology, in the thoracic or lumbar spine who underwent posterior-only approach surgery at our hospital. OUTCOME MEASURES: Neurologic status was assessed using the Frankel grading system preoperatively, postoperatively, and at final follow-up. METHODS: The patients were allocated into two groups based on the presence of postoperative residual neurologic deficits. Patients' demographic, clinical, and factors based on magnetic resonance imaging (MRI) were analyzed for their influence on residual neurologic deficits. Clinical factors included age, sex, diabetes, comorbidities, pathogens, affected spinal levels, the interval between onset of symptoms to surgery, preoperative neurologic status, presence of cauda equina syndrome, and surgical procedures. MRI factors included the distribution of abscesses within the spinal canal, presence of ring enhancement, presence of paravertebral abscess or psoas abscess, canal compromise anteroposterior (AP) ratio and cross-sectional area ratio, abscess length, and abscess thickness. RESULTS: Thirty-five of the 53 patients (66%) had preoperative neurologic deficits, and 21 of 53 patients (40%) had postoperative residual neurologic deficits. Patients' neurologic status improved significantly after the surgery (p<.001). Risk factors including age, diabetes, cauda equina syndrome, presence of anterior with posterior (A+P) dural abscess, canal compromise AP ratio, cross-sectional area ratio, abscess length, and abscess thickness were significantly correlated with postoperative residual neurologic deficits. In multivariate logistic regression analysis, age ≥70 years, preoperative cauda equina syndrome, abscess length ≥5.5 cm and abscess thickness ≥0.8 cm were the four most significant factors related to residual neurologic deficits. CONCLUSIONS: In patients with SEA of the thoracic and lumbar spine, age ≥70 years, preoperative cauda equina syndrome, abscess length ≥5.5 cm and abscess thickness ≥0.8 cm were the most significant preoperative risk factors for residual neurologic deficits after surgery.

Risk Factors of Cage Subsidence in Patients Received Minimally Invasive Transforaminal Lumbar Interbody Fusion.

STUDY DESIGN: A retrospective cohort study. OBJECTIVE: To determine the risk factors of cage subsidence in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and its correlation with patient-reported outcomes. SUMMARY OF BACKGROUND DATA: Cage subsidence is among the cage-related complications after TLIF and may lead to poor outcomes. Few studies have addressed the incidence of cage subsidence in MI-TLIF. METHODS: This retrospective study of a prospectively collected database was conducted from October 2015 to October 2017. All patients received MI-TLIF with a minimum of 2-year follow-up. All levels were separated into the cage subsidence (CS group) and no cage subsidence (non-CS group) groups. Cage subsidence was evaluated using lateral radiographs and defined as more than 2 mm migration of the cage into the endplate of adjacent vertebral body. Patient demographics, perioperative details, and radiographic parameters were recorded. Cage-related parameters were cage height, cage insertion level, and cage position. Cage position was recorded using central point ration (CPR). Patient-reported outcome was analyzed using the Oswestry Disability Index (ODI) questionnaire and Visual Analog Scale (VAS) preoperatively and at 2 years postoperatively. RESULTS: Ninety-three patients (126 levels) were included. Mean age was 66.5 years with an average follow-up of 36.9 months. Overall incidence of cage subsidence was 34.1%. The CS group had significantly higher body mass index, less bone mineral density (BMD), shorter disc height, and higher CPR than the non-CS group. BMD, disc height, and CPR were significantly negatively correlated with depth of cage subsidence. ODI improvement was significantly lesser in the CS group than in the non-CS group. Fusion rate and complications were unrelated to cage subsidence. CONCLUSION: The BMD, disc height, and cage position were the most significant risk factors that were negatively correlated with depth of cage subsidence. Placing a TLIF cage anteriorly if possible may reduce the risk of cage subsidence. LEVEL OF EVIDENCE: 3.

Functional outcomes and survival after surgical stabilization for inoperable non-small-cell lung cancer with spinal metastasis of the thoracic and lumbar spines: a retrospective comparison between epidermal growth factor receptor-tyrosine kinase inhibitor and platinum-based chemotherapy groups.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: To compare the surgical results between targeted therapy and post-operative chemotherapy for patients with spinal metastasis of inoperable non-small-cell lung cancer (NSCLC). SETTING: Single-center study at an academic orthopedic department in Taiwan. METHODS: Sixty-five patients were treated surgically for spinal metastasis of inoperable NSCLC with long posterior instrumentation with or without posterior decompression according to the patient's neurologic status. Post-operative radiotherapy of the spinal lesion and targeted therapy or chemotherapy were done following surgery after the surgical wound healed. Post-operative clinical outcomes and survival were evaluated and compared between these two groups. The overall survival represented survival from the date of diagnosis to death. RESULTS: Thirty-five patients were grouped as the targeted therapy group and 30 patients as the chemotherapy group. The overall median survival times were 12.0 and 10.0 months in the targeted therapy and chemotherapy groups, respectively. Sixty-two patients were able to walk with or without an aid postoperatively. There was no significant difference observed between these two groups in terms of pain relief, neurologic improvement, ambulatory improvement, and survival. CONCLUSIONS: Surgical stabilization with or without laminectomy improved functional outcomes in patients with inoperable non-small-cell lung cancer, and post-operative functional outcomes were similar between chemotherapy and targeted therapy groups. A longer survival was observed with targeted therapy for the patients whose NSCLC was diagnosed before spinal metastasis, however, the longer survival was not statistically significant.

Is bony attachment necessary for dynamic reference frame in navigation-assisted minimally invasive lumbar spine fusion surgery?

This study aimed to compare the accuracy of navigation-assisted percutaneous pedicle screw insertions between traditional posterior superior iliac spine (PSIS) fixed and cutaneously fixed dynamic reference frame (DRF) in minimally invasive surgery of transforaminal lumbar interbody fusion (MIS TLIF). This is a prospective randomized clinical study. Between May 2016 and Nov 2017, 100 patients who underwent MIS TLIF were randomly divided into bone fixed group (with PSIS fixed DRF) and skin fixed group (with cutaneously fixed DRF). The pedicel screws were inserted under navigational guidance using computed tomography (CT) data acquired intraoperatively with a Ziehm 3-dimensional fluoroscopy-based navigation system. Screw positions were immediately checked by a final intraoperative scan. The accuracy of screw placement was evaluated by a sophisticated computed tomography protocol. Both groups had similar patient demographics. Totally Five-hundred Twelve pedicle screws were placed in the lumbar spine. There were 2 moderate (2-4 mm) pedicle perforations in each group. The accuracy showed no significant difference between bone fixed and skin fixed DRF. There were no significant procedure-related complications. The skin fixed DRF provides similar accuracy in pedicle screw insertions with bone fixed DRF using intraoperative 3D image guided navigation in MIS TLIF. Skin fixed DRF not only serves as an alternative method but also saves a separate incision wound for bony attachment.

Intra-articular Injection of Tranexamic Acid Reduced Postoperative Hemarthrosis in Arthroscopic Anterior Cruciate Ligament Reconstruction: A Prospective Randomized Study.

PURPOSE: To evaluate the effect of intra-articular injection of tranexamic acid (TXA) in patients receiving arthroscopic anterior cruciate ligament reconstruction (ACLR). METHODS: A total of 304 patients were included in this study, which was performed between August 2017 and April 2018. Single-bundle reconstructions using autologous hamstring tendon grafts were performed in all patients. Patients were randomized into 2 groups: Group 1 patients (TXA group) received the index procedure with a 10-mL intra-articular injection of TXA (100 mg/mL). Group 2 patients (control group) received the index procedure without TXA injections. An intra-articular suction drain was placed in the joint and clamped for 2 hours after the procedure. The volume of drainage was recorded 24 hours after surgery. Clinical evaluations using the International Knee Documentation Committee functional score, range of motion, and a visual analog scale pain score were performed on day 3 and at week 4 postoperatively. RESULTS: Twenty-four hours after surgery, a significant decrease in the amount of drainage was observed in patients receiving intra-articular injections (TXA group, 56.1 ± 34.1 mL; control group, 80.1 ± 48 mL; P < .05). On day 3 and at week 4, significantly reduced pain scores were reported in the TXA group. However, at week 4, clinical function scores did not show significant differences between the 2 groups. CONCLUSIONS: Intra-articular injection of TXA could significantly reduce postoperative intra-articular bleeding in the first 24 hours in patients receiving arthroscopic ACLR. TXA injection may also decrease pain and the grade of hemarthrosis in the early postoperative period. No systemic side effects or need for aspiration was noted during the follow-up period. Therefore, intra-articular injection of TXA could be considered an effective and relatively safe solution to reduce postoperative bleeding and pain in ACLR patients. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Differences in the interbody bone graft area and fusion rate between minimally invasive and traditional open transforaminal lumbar interbody fusion: a retrospective short-term image analysis.

PURPOSE: We aimed to quantify the interbody bone graft area following transforaminal lumbar interbody fusion (TLIF) using traditional open and minimally invasive surgeries (MIS) and investigate their correlations with rates of fusion, complications, and clinical outcomes. METHODS: Patients undergoing TLIF of 1 or 2 levels between October 2015 and December 2016 were retrospectively included. Fusion and bone graft areas were assessed with computed tomography (CT) at 6 months postoperatively. The bone graft area ratio was defined as the bone graft area divided by the average endplate area. The distributions of bone graft area within the discs were also recorded. Clinical outcomes were assessed using the visual analog scale (VAS) and Oswestry Disability Index (ODI) questionnaires. RESULTS: In total, 77 disc levels in 57 patients were analyzed. The fusion rate was 79.1% in the open group and 82.4% in the MIS group (p = 0.718). Clinical outcomes of both groups improved significantly. Changes in VAS and ODI scores at 12 months postoperatively were comparable between groups. Bone graft area ratio was not significantly different between the two groups (open, 38 ± 10.8%; MIS, 38.1 ± 9.0%, p = 0.977). Analysis of bone graft distribution revealed that the contralateral-dorsal part of the disc had the lowest bone graft area. The bone graft area ratio was significantly higher in the solid union group (39.2 ± 10.4%) than in the non-solid union group (33.5 ± 6.4%, p = 0.048). CONCLUSIONS: The fusion rates, bone graft area ratios, clinical outcomes, and complications were similar between MIS and open TLIF. These slides can be retrieved under Electronic Supplementary Material.