Diagnostic performance of computed tomography-digital subtraction angiography and conventional magnetic resonance imaging for evaluating the vascularity of osseous spinal tumors.

BACKGROUND AND PURPOSE: Patients with hypervascular spinal tumors may have severe blood loss during tumor resection, which increases the risks of perioperative morbidity and mortality. However, the preoperative evaluation of tumor vascularity may be challenging; moreover, the reliability of the data obtained in conventional preoperative noninvasive imaging is debatable. In this study, we compared conventional magnetic resonance imaging (MRI) and subtraction computed tomography angiography (CTA) in terms of their performance in vascularity evaluation. The catheter digital subtraction angiography (DSA) technique was used as a reference standard. METHODS: This study included 123 consecutive patients with spinal tumor who underwent subtraction CTA, catheter DSA, and subsequent surgery between October 2015 and October 2021. Data regarding qualitative and semiquantitative subtraction CTA parameters and conventional MRI signs were collected for comparison with tumor vascularity graded through catheter DSA. The diagnostic performance of qualitative CTA, quantitative CTA, and conventional MRI in assessing spinal tumor vascularity was analyzed. RESULTS: Qualitative subtraction CTA was the best noninvasive imaging modality in terms of diagnostic performance (area under the receiver operating characteristic curve [AUROC], 0.95). Quantitative CTA was relatively inferior (AUROC, 0.87). MRI results had low reliability (AUROC, 0.51 to 0.59). Intratumoral hemorrhage and prominent foraminal venous plexus were found to be the specific signs for hypervascularity (specificity 93.2%). CONCLUSIONS: Qualitative subtraction CTA offers the highest diagnostic value in evaluating spinal tumor vascularity, compared to quantitative CTA and MRI. Although conventional MRI may not be a reliable approach, certain MRI signs may have high specificity, which may be crucial for assessing spinal tumor vascularity.

Efficacy of preoperative embolization for metastatic spinal tumor surgery using angiographic vascularity assessment.

OBJECTIVES: Preoperative embolization (PE) for metastatic spinal tumors is a method of minimizing intraoperative blood loss during aggressive surgery. This study specified angiographic standards and investigated the influence of these and other factors on blood loss in patients with spinal metastases and various pathologies. METHODS: The cohort comprised 126 consecutive patients receiving PE from 2015 to 2021. Their clinical, surgical, and angiographic characteristics were reviewed. Standard angiographic grading was used for vascularity assessment. Degree of embolization was divided into complete (≥ 90%), near complete (67 to < 90%), and partial (< 67%). Logistic regression analysis was used to investigate factors predictive of massive blood loss (> 2500 mL). A proportional odds model was used to assess factors predictive of the degree of embolization. RESULTS: Mean intraoperative blood loss was 1676 mL. Among the patients, 62 had hypervascular tumors and 64 had nonhypervascular tumors, according to the angiographic classification. Intraoperative blood loss differed significantly with embolization degree, both overall (p < 0.001) and in the hypervascular and nonhypervascular groups (p = 0.01 and 0.03). Angiographic hypervascularity, spinal metastasis invasiveness index, and embolization degree were significant predictors of massive blood loss in univariate analysis, but only embolization degree was significant in multivariate analysis. Only the presence of the radiculomedullary artery at the target level was significant in both the univariate and multivariate analyses for embolization degree. CONCLUSIONS: In addition to pathological classification, angiographic vascularity assessment is valuable. Although complete embolization is a reasonable goal, it is challenging to achieve in cases of visible radiculomedullary artery. KEY POINTS: • Angiography has a supplementary role in vascularity assessment for spinal metastatic surgery. • Better embolization degree is associated with less intraoperative blood loss in both angiographic hypervascular and nonhypervascular groups. • Presence of radiculomedullary artery in the target level causes worse embolization outcome.

Pullout strength of different pedicle screws after primary and revision insertion: an in vitro study on polyurethane foam.

BACKGROUND: Surgeons are routinely required to remove loose or failed pedicle screws and insert a new screw in their place. However, inserting a new screw into an existing hole may compromise the holding capacity of the pedicle screw. The purpose of this study is to evaluate the pullout strength of pedicle screws with different thread designs after the primary insertion and revision surgery in a synthetic bone model. METHODS: Four pedicle screws with different thread designs (single-lead-thread (SLT) screw, dual-lead-thread (DLT) screw, mixed-single-lead-thread (MSLT) screw, and proximal-unthreaded-dual-thread (PUDL) screw) were inserted into pre-drilled, untapped holes (ø 4.2 mm, length 35 mm) in Sawbone blocks of density 20 pcf. In the first sequence, a 6.0 mm screw was inserted into the predrilled foam block and the primary pullout strength of the screw was measured according to ASTM F543. In the second sequence, a 6.0 mm screw was inserted and removed, and then either a 6.5 mm screw of the same design or a different screw design was inserted into the same hole and the pullout strength recorded. RESULTS: In the first sequence, the mean pullout strength of the MSLT screw was significantly (p < 0.05) greater than all other screw designs. In the second sequence, when the MSLT screw was the primary screw, using a larger MSLT screw (6.5 mm) as the revision screw did not lead to a higher pullout strength than if a 6.0 mm diameter PUDL screw was used for the revision. Using a larger DLT screw (6.5 mm) as the revision screw resulted in a significantly (p < 0.05) greater pullout strength than a 6.0 mm STL, DLT, MSLT, or PUDL screw. CONCLUSIONS: Our results indicate that employing classic oversizing of the same screw design is a safe choice for maintaining screw purchase in the bone after revision. In cases where oversizing with the same screw design is not practical, opting for a PUDL screw with the same original diameter can provide enough purchase in the bone to maintain stability.

Changes in the quick mild cognitive impairment test over time: A normative study in an adult sample in Taiwan.

BACKGROUND: The Quick Mild Cognitive Impairment (Qmci) test has been suggested to be an easy-to-use and precise screening tool for detecting postoperative cognitive dysfunction (POCD). To provide essential information for future POCD studies in Taiwan, the present study provided data regarding the Taiwan version of the Qmci (Qmci-TW) test conducted in the normative Taiwanese population and changes in them over time. METHODS: The present study recruited adult native Taiwanese volunteers without known neurologic or psychiatric diseases. All enrolled participants received protocolized serial Qmci-TW test at baseline, 2-day follow-up, and 6-month follow-up. RESULTS: In total, 30 participants, 15 men and 15 women, were enrolled in this study. The baseline Qmci-TW score ranged from 55 to 80, with a mean of 68.9 and a standard deviation (SD) of 7. At 2-day follow-up, the mean Qmci-TW test score was significantly higher (by 5.3; SD = 7.3) than that at baseline (P = 0.001). At 6-month follow-up, the mean Qmci-TW score was 71.3 (SD = 6.1), with no significant difference compared with that at baseline. The decline in Qmci-TW scores by > 9 points on postoperative day 1 and by > 11 points at 6-month follow-up was the criterion for POCD. CONCLUSION: The present study provided data regarding the Qmci-TW test conducted in the normative Taiwanese population and its time trajectory during the 6-month follow-up.

Deviating from the Recommended Torque on Set Screws Can Reduce the Stability and Fatigue Life of Pedicle Screw Fixation Devices.

Background and Objectives: Using an appropriate torque to tighten set screws ensures the long-term stability of spinal posterior fixation devices. However, the recommended torque often varies between different devices and some devices do not state a recommended torque level. The purpose of this study is to evaluate the effect of set screw torque on the overall construct stability and fatigue life. Materials and Methods: Two commercial pedicle screw systems with different designs for the contact interface between the set screw and rod (Group A: plane contact, Group B: line contact) were assembled using torque wrenches provided with the devices to insert the set screws and tighten to the device specifications. The axial gipping capacity and dynamic mechanical stability of each bilateral construct were assessed in accordance with ASTM F1798 and ASTM F1717. Results: Increasing or decreasing the torque on the set screw by 1 Nm from the recommended level did not have a significant effect on the axial gripping capacity or fatigue strength of Group A (p > 0.05). For Group B, over-tightening the set screw by 1 Nm did cause a significant reduction in the fatigue strength. Conclusions: Excessive torque can damage the rod surface and cause premature failure. When insertion using a manual driver is preferred, a plane contact interface between the set screw and rod can reduce damage to the rod surface when the set screw is over-torqued.

A Dynamic Interbody Cage Improves Bone Formation in Anterior Cervical Surgery: A Porcine Biomechanical Study.

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) with a rigid interbody spacer is commonly used in the treatment of cervical degenerative disc disease. Although ACDF relieves clinical symptoms, it is associated with several complications such as pseudoarthrosis and adjacent segment degeneration. The concept of dynamic fusion has been proposed to enhance fusion and reduce implant subsidence rate and post-fusion stiffness; this pilot preclinical animal study was conducted to begin to compare rigid and dynamic fusion in ACDF. QUESTIONS/PURPOSES: Using a pig model, we asked, is there (1) decreased subsidence, (2) reduced axial stiffness in compression, and (3) improved likelihood of bone growth with a dynamic interbody cage compared with a rigid interbody cage in ACDF? METHODS: ACDF was performed at two levels, C3/4 and C5/6, in 10 pigs weighing 48 to 55 kg at the age of 14 to 18 months (the pigs were skeletally mature). One level was implanted with a conventional rigid interbody cage, and the other level was implanted with a dynamic interbody cage. The conventional rigid interbody cage was implanted in the upper level in the first five pigs and in the lower level in the next five pigs. Both types of interbody cages were implanted with artificial hydroxyapatite and tricalcium phosphate bone grafts. To assess subsidence, we took radiographs at 0, 7, and 14 weeks postoperatively. Subsidence less than 10% of the disc height was considered as no radiologic abnormality. The animals were euthanized at 14 weeks, and each operated-on motion segment was harvested. Five specimens from each group were biomechanically tested under axial compression loading to determine stiffness. The other five specimens from each group were used for microCT evaluation of bone ingrowth and ongrowth and histologic investigation of bone formation. Sample size was determined based on 80% power and an α of 0.05 to detect a between-group difference of successful bone formation of 15%. RESULTS: With the numbers available, there was no difference in subsidence between the two groups. Seven of 10 operated-on levels with rigid cages had subsidence on a follow-up radiograph at 14 weeks, and subsidence occurred in two of 10 operated-on levels with dynamic cages (Fisher exact test; p = 0.07). The stiffness of the unimplanted rigid interbody cages was higher than the unimplanted dynamic interbody cages. After harvesting, the median (range) stiffness of the motion segments fused with dynamic interbody cages (531 N/mm [372 to 802]) was less than that of motion segments fused with rigid interbody cages (1042 N/mm [905 to 1249]; p = 0.002). Via microCT, we observed bone trabecular formation in both groups. The median (range) proportions of specimens showing bone ongrowth (88% [85% to 92%]) and bone volume fraction (87% [72% to 100%]) were higher in the dynamic interbody cage group than bone ongrowth (79% [71% to 81%]; p < 0.001) and bone volume fraction (66% [51% to 78%]; p < 0.001) in the rigid interbody cage group. The percentage of the cage with bone ingrowth was higher in the dynamic interbody cage group (74% [64% to 90%]) than in the rigid interbody cage group (56% [32% to 63%]; p < 0.001), and the residual bone graft percentage was lower (6% [5% to 8%] versus 13% [10% to 20%]; p < 0.001). In the dynamic interbody cage group, more bone formation was qualitatively observed inside the cages than in the rigid interbody cage group, with a smaller area of fibrotic tissue under histologic investigation. CONCLUSION: The dynamic interbody cage provided satisfactory stabilization and percentage of bone ongrowth in this in vivo model of ACDF in pigs, with lower stiffness after bone ongrowth and no difference in subsidence. CLINICAL RELEVANCE: The dynamic interbody cage appears to be worthy of further investigation. An animal study with larger numbers, with longer observation time, with multilevel surgery, and perhaps in the lumbar spine should be considered.

Neuroprotective effects of intraoperative dexmedetomidine versus saline infusion combined with goal-directed haemodynamic therapy for patients undergoing cranial surgery: A randomised controlled trial.

BACKGROUND: By inhibiting neuroinflammation dexmedetomidine may be neuroprotective in patients undergoing cranial surgery, but it reduces cardiac output and cerebral blood flow. OBJECTIVE: To investigate whether intra-operative dexmedetomidine combined with goal-directed haemodynamic therapy (GDHT) has neuroprotective effects in cranial surgery. DESIGN: A double-blind, single-institution, randomised controlled trial. SETTING: A single university hospital, from April 2017 to April 2020. PATIENTS: A total of 160 adults undergoing elective cranial surgery. INTERVENTION: Infusion of dexmedetomidine (0.5 µg kg-1 h-1) or saline combined with GDHT to optimise stroke volume during surgery. MAIN OUTCOME MEASURES: The proportion who developed postoperative neurological complications was compared. Postoperative disability was assessed using the Barthel Index at time points between admission and discharge, and also the 30-day modified Rankin Scale (mRS). Postoperative delirium was assessed. The concentration of a peri-operative serum neuroinflammatory mediator, high-mobility group box 1 protein (HMGB1), was compared. RESULTS: Fewer patients in the dexmedetomidine group developed new postoperative neurological complications (26.3% vs. 43.8%; P = 0.031), but the number of patients developing severe neurological complications was comparable between the two groups (11.3% vs. 20.0%; P = 0.191). In the dexmedetomidine group the Barthel Index reduction [0 (-10 to 0)] was less than that in the control group [-5 (-15 to 0)]; P = 0.023, and there was a more favourable 30-day mRS (P = 0.013) with more patients without postoperative delirium (84.6% vs. 64.2%; P = 0.012). Furthermore, dexmedetomidine induced a significant reduction in peri-operative serum HMGB1 level from the baseline (222.5 ±â€Š408.3 pg ml-1) to the first postoperative day (152.2 ±â€Š280.0 pg ml-1) P = 0.0033. There was no significant change in the control group. The dexmedetomidine group had a lower cardiac index than did the control group (3.0 ±â€Š0.8 vs. 3.4 ±â€Š1.8 l min-1 m-2; P = 0.0482) without lactate accumulation. CONCLUSIONS: Dexmedetomidine infusion combined with GDHT may mitigate neuroinflammation without undesirable haemodynamic effects during cranial surgery and therefore be neuroprotective. TRIAL REGISTRATION: Clinicaltrials.gov Identifier: NCT02878707.

Contemporary management of pediatric spinal tumors: a single institute's experience in Taiwan in the modern era.

INTRODUCTION: Pediatric spinal tumors are unique pathologies treated by pediatric neurosurgeons. Special attention is required for the preservation of neural function and bony alignment. We reported our experience in the management of these challenging lesions. METHODS: A total of 75 pediatric patients with spinal tumors treated at the National Taiwan University Hospital from 1998 to 2018 were identified retrospectively. Clinical data, radiographic image, and pathological report were reviewed for analysis. RESULTS: There were 37 females and 38 males. The median age was 9 years. Thirty-eight tumors (50.6%) were extradural, 20 (26.7%) intradural extramedullary, and 17 (22.6%) intramedullary. The most common pathologies were glioma, ependymoma, and neuroblastoma. The rate of total and subtotal resection was 45.3% and 21.3%. Thirty-four patients (45.3%) required post-operative adjuvant therapy. Eight patients (10.6%) with spinal deformity had simultaneous tumor excision and spinal fusion surgery. Additional six (8%) patients had subsequent spinal fixation and fusion for deformity after primary tumor operation. Eighty-four percent of patients were ambulatory 3 years after operation. For patients with intradural extramedullary and intramedullary tumors, worse survival outcome was associated with tumor derived from CSF seeding and cranial involvement of spinal tumor, while poorer functional outcome was correlated with cranial involvement and adjuvant therapy with chemotherapy or radiotherapy. CONCLUSIONS: Pediatric spinal tumor surgery carries low surgical morbidity and mortality under current standard of neurosurgical practice. Post-operative adjuvant therapy is required for nearly half of the cases. Spinal deformity requires special attention and sometimes surgical correction. Contemporary management of pediatric spinal tumors enables effective ablation of the lesion and delivers favorable outcome for the majority of patients.

Biomechanical analysis of single-level interbody fusion with different internal fixation rod materials: a finite element analysis.

BACKGROUND: Lumbar spinal fusion with rigid spinal fixators as one of the high risk factors related to adjacent-segment failure. The purpose of this study is to investigate how the material properties of spinal fixation rods influence the biomechanical behavior at the instrumented and adjacent levels through the use of the finite element method. METHODS: Five finite element models were constructed in our study to simulate the human spine pre- and post-surgery. For the four post-surgical models, the spines were implanted with rods made of three different materials: (i) titanium rod, (ii) PEEK rod with interbody PEEK cage, (iii) Biodegradable rod with interbody PEEK cage, and (iv) PEEK cage without pedicle screw fixation (no rods). RESULTS: Fusion of the lumbar spine using PEEK or biodegradable rods allowed a similar ROM at both the fusion and adjacent levels under all conditions. The models with PEEK and biodegradable rods also showed a similar increase in contact forces at adjacent facet joints, but both were less than the model with a titanium rod. CONCLUSIONS: Flexible rods or cages with non-instrumented fusion can mitigate the increased contact forces on adjacent facet joints typically found following spinal fixation, and could also reduce the level of stress shielding at the bone graft.

Effect of lordosis on adjacent levels after lumbar interbody fusion, before and after removal of the spinal fixator: a finite element analysis.

BACKGROUND: Literature indicates that adjacent-segment diseases after posterior lumbar interbody fusion with pedicle screw fixation accelerate degenerative changes at unfused adjacent segments due to the increased motion and intervertebral stress. Sagittal alignment of the spine is an important consideration as achieving proper lordosis could improve the outcome of spinal fusion and avoid the risk of adjacent segment diseases. Therefore, restoration of adequate lumbar lordosis is considered as a major factor in the long-term success of lumbar fusion. This study hypothesized that the removal of internal fixation devices in segments that have already fused together could reduce stress at the disc at adjacent segments, particularly in patients with inadequate lordosis. The purpose of this study was to analyze the biomechanical characteristics of a single fusion model (posterior lumbar interbody fusion with internal fixation) with different lordosis angles before and after removal of the internal fixation device. METHODS: Five finite element models were constructed for analysis; 1) Intact lumbar spine without any implants (INT), 2) Lumbar spine implanted with a spinal fixator and lordotic intervertebral cage at L4-L5 (FUS-f-5c), 3) Lumbar spine after removal of the spinal fixator (FUS-5c), 4) Lumbar spine implanted with a spinal fixator and non-lordotic intervertebral cage at L4-L5 (FUS-f-0c), and 5) Lumbar spine after removal of the spinal fixator from the FUS-f-0c model (FUS-0c). RESULTS: The ROM of adjacent segments in the FUS-f-0c model was found to be greater than in the FUS-f-5c model. After removing the fixator, the adjacent segments in the FUS-5c and FUS-0c models had a ROM that was similar to the intact spine under all loading conditions. Removing the fixator also reduced the contact forces on adjacent facet joints and reduced the peak stresses on the discs at adjacent levels. The greatest increase in stress on the discs was found in the FUS-f-0c model (at both L2/L3 and L3/L4), with intervertebral stress at L3/L4 increasing by 83% when placed in flexion. CONCLUSIONS: This study demonstrated how removing the spinal fixation construct after bone fusion could reduce intradiscal pressure and facet contact forces at adjacent segments, while retaining a suitable level of lumbar lordosis.

Surgical Versus Non-Surgical Treatment for Thoracolumbar Burst Fractures Without Neurological Deficit: A Systematic Review and Meta-Analysis.

STUDY DESIGN: A systematic review and meta-analysis. OBJECTIVE: To update the systematic review comparing the outcomes between surgical and non-surgical treatment for thoracolumbar burst fractures without neurological deficit. METHODS: We registered a protocol in PROSPERO (ID: CRD42021291769) and searched Medline, Embase, Web of Science, and Google Scholar databases. Surgical and non-surgical treatments were compared in patients with thoracolumbar burst fractures without neurological deficits. Predefined outcomes at ≥6 months included pain (defined as a visual analog scale [VAS] of 0-100), functional outcomes (Oswestry Disability Index [ODI] of 0-50 and Roland-Morris Disability Questionnaire [RMDQ] of 0-24), and kyphotic angulation. RESULTS: Nineteen studies involving 1056 patients were included in the analyses. For outcomes at ≥6 months, little to no difference was found in pain VAS score (mean difference, .95 [95% confidence interval {CI}, -6.02 to 7.92]; 827 participants; 15 studies; I2 = 92%), ODI (mean difference, -1.40 [95% CI, -5.11 to 2.31]; 446 participants; 7 studies; I2 = 79%), and RMDQ (mean difference, -.73 [95% CI, -5.13 to 3.66]; 216 participants; 5 studies; I2 = 77%). The kyphotic angulation in the surgery group was 6.35° lower than that in the non-surgery group (mean difference, -6.56° [95% CI, -10.26° to -2.87°]; 527 participants; ten studies; I2 = 86%). The trial sequential analysis indicated all outcomes reached adequate statistical power. The certainty of the evidence for all 4 outcomes was very low. For the analysis of minimally invasive procedures compared to traditional open surgeries, a statistically significant subgroup difference was found for VAS and ODI (P < .01 and P < .04, respectively). CONCLUSION: Surgical and non-surgical treatments showed little or no difference in outcomes at ≥6 months. This review provides a conclusion with adequate statistical power by including non-randomized studies. However, non-randomized studies also lowered the certainty of the evidence to a very low level.

Perioperative growth hormone levels as an early predictor of new-onset secondary adrenal insufficiency following transsphenoidal pituitary tumor resection.

OBJECTIVE: This study aims to predict new-onset secondary adrenal insufficiency (NOSAI) after transsphenoidal pituitary tumor resection surgery using perioperative growth hormone (GH) and prolactin (PRL) levels, among other factors. METHODS: A cohort of 124 adult patients who underwent transsphenoidal resection for non-functioning pituitary adenoma, with routine perioperative glucocorticoid use, was used to develop the predictive regression model. An additional 46 patients served as the validation cohort. Generalized additive models were used to identify optimal cut-off points for the variables. RESULTS: The GH level on postoperative day one (POD1) can be a simple predictor by implementing a cut-off point of 0.41 ng/ml. A value ≤ 0.41 ng/mL predicted NOSAI with 0.6316 sensitivity and 0.7810 specificity for the original cohort and 1.0000 sensitivity and 0.7143 specificity for the validation cohort. The multiple logistic regression model included perioperative PRL level difference, perioperative GH level difference, intraoperative cerebrospinal fluid (CSF) leakage, tumor size, and the combined effect of diabetes insipidus (DI) and relative perioperative GH level difference. The areas under the receiver operating characteristic curves were 0.9410 (original cohort) and 0.9494 (validation cohort) for the regression model. CONCLUSION: Early morning GH level on POD1 can predict NOSAI with fair accuracy when perioperative stress dose glucocorticoid is administered. Prediction accuracy can be improved by considering CSF leakage, DI, and perioperative changes in GH and PRL in the final regression model.

Validity of the I­FEED classification in assessing postoperative gastrointestinal impairment in patients undergoing elective lumbar spinal surgery with general anesthesia: a prospective observational study.

BACKGROUND: The I-FEED classification, scored 0-8, was reported to accurately describe the clinical manifestations of gastrointestinal impairment after colorectal surgery. Therefore, it is interesting to determine whether the I-FEED scoring system is also applicable to patients undergoing lumbar spine surgery. METHODS: Adult patients undergoing elective lumbar spine surgery were enrolled, and the I-FEED score was measured for 4 days after surgery. The I-FEED scoring system incorporates five elements: intake (score: 0, 1, 3), feeling nauseated (score: 0, 1, 3), emesis (score: 0, 1, 3), results of physical exam (score: 0, 1, 3), and duration of symptoms (score: 0, 1, 2). Daily I-FEED scores were summed, and the highest overall score is used to categorize patients into one of three categories: normal (0-2 points), postoperative gastrointestinal intolerance (POGI; 3-5 points), and postoperative gastrointestinal dysfunction (POGD; 6 + points). The construct validity hypothesis testing determines whether the I-FEED category is consistent with objective clinical findings relevant to gastrointestinal impairment, namely, the longer length of hospital stay (LOS), higher inhospital medical cost, more postoperative gastrointestinal medical treatment, and more postoperative non-gastrointestinal complications. RESULTS: A total of 156 patients were enrolled, and 25.0% of patients were categorized as normal, 49.4% POGI, and 25.6% POGD. Patients with higher I-FEED scores agreed with the four validity hypotheses. Patients with POGD had a significantly longer length of hospital stay (1 day longer median stay; p = 0.049) and more inhospital medical costs (approximately 500 Taiwanese dollars; p = 0.037), and more patients with POGD required rectal laxatives (10.3% vs. 32.5% vs. 32.5%; p = 0.026). In addition, more patients with POGD had non-gastrointestinal complications (5.1% vs. 11.7% vs. 30.0%; p = 0.034). CONCLUSION: This study contributes preliminary validity evidence for the I-FEED score as a measure for postoperative gastrointestinal impairment after elective lumbar spine surgery.

Overall Survival of Non-Small Cell Lung Cancer With Spinal Metastasis: A Systematic Review and Meta-Analysis.

OBJECTIVE: The long-term survival data of lung cancer patients with spinal metastases are crucial for informed treatment decision-making. However, most studies in this field involve small sample sizes. Moreover, survival benchmarking and an analysis of changes in survival over time are required, but data are unavailable. To meet this need, we performed a metaanalysis of survival data from small studies to obtain a survival function based on largescale data. METHODS: We performed a single-arm systematic review of survival function following a published protocol. Data of patients who received surgical, nonsurgical, and mixed modes of treatment were meta-analyzed separately. Survival data were extracted from published figures with a digitizer program and then processed in R. Median survival time was used as an effect size for moderator analysis to explain the heterogeneity. RESULTS: Sixty-two studies with 5,242 participants were included for pooling. The survival functions showed a median survival of 6.72 months for surgery (95% confidence interval [CI], 61.9-7.01; 2,367 participants; 36 studies), 5.99 months for nonsurgery (95% CI, 5.33-6.47; 891 participants; 12 studies), and 5.96 months for mixed (95% CI, 5.67-6.43; 1,984 participants; 18 studies). Patients enrolled since 2010 showed the highest survival rates. CONCLUSION: This study provides the first large-scale data for lung cancer with spinal metastasis that allows survival benchmarking. Data from patients enrolled since 2010 had the best survival and thus may more accurately reflect current survival. Researchers should focus on this subset in future benchmarking and remain optimistic in the management of these patients.

Mechanical performance of porous biomimetic intervertebral body fusion devices: an in vitro biomechanical study.

BACKGROUND: Degenerative disc disease is one of the most common ailments severely affecting the quality of life in elderly population. Cervical intervertebral body fusion devices are utilized to provide stability after surgical intervention for cervical pathology. In this study, we design a biomimetic porous spinal cage, and perform mechanical simulations to study its performances following American Society for Testing and Materials International (ASTM) standards before manufacturing to improve design process and decrease cost and consumption of material. METHODS: The biomimetic porous Ti-6Al-4 V interbody fusion devices were manufactured by selective laser melting (laser powder bed fusion: LPBF in ISO/ASTM 52900 standard) and subsequently post-processed by using hot isostatic pressing (HIP). Chemical composition, microstructure and the surface morphology were studied. Finite element analysis and in vitro biomechanical test were performed. FINDINGS: The post heat treatment can optimize its mechanical properties, as the stiffness of the cage decreases to reduce the stress shielding effect between two instrumented bodies. After the HIP treatment, the ductility and the fatigue performance are substantially improved. The use of HIP post-processing can be a necessity to improve the physical properties of customized additive manufacturing processed implants. INTERPRETATION: In conclusion, we have successfully designed a biomimetic porous intervertebral device. HIP post-treatment can improve the bulk material properties, optimize the device with reduced stiffness, decreased stress shielding effect, while still provide appropriate space for bone growth. CLINICAL SIGNIFICANCE: The biomechanical performance of 3-D printed biomimetic porous intervertebral device can be optimized. The ductility and the fatigue performance were substantially improved, the simultaneously decreased stiffness reduces the stress shielding effect between two instrumented bodies; while the biomimetic porous structures provide appropriate space for bone growth, which is important in the patients with osteoporosis.

Metastatic spinal cord compression as the first manifestation of malignancy: A retrospective study of surgical outcome from single institution.

BACKGROUND: Given the limited studies addressing the issue about the effect of different surgical modalities for metastatic spinal cord compression (MSCC) as the first malignancy manifestation, we conducted a retrospective case-control study to evaluate the surgical outcome of MSCC as the first malignancy manifestation. METHODS: A total of 128 patients who were suspected of having metastatic spinal cord compression and underwent surgery from 2008 to 2021 were enrolled in the study. All patients were categorized into either 'debulking group' or 'palliative group'. RESULTS: The primary outcome was progression-free survival (PFS). The secondary outcomes were overall survival (OS), Frankel scale, and Karnofsky scores. All the outcomes were analyzed with a data cutoff of December 31, 2021. There was a significant difference between groups in progression-free survival (PFS) (p = 0.0094). However, there was no significant difference between groups in the overall survival (OS) (p = 0.0746). Age of onset, gender, duration of symptoms, and location of spinal metastasis, initial Frankel, initial Tomita scores, and initial Karnofsky performance scale showed no significant differences between groups. CONCLUSION: In conclusion, debulking surgery was shown to provide better neurological recoveries and could be considered first in patients with metastatic spinal cord compression as the first malignancy manifestation.

Pullout Strength of Pedicle Screws Inserted Using Three Different Techniques: A Biomechanical Study on Polyurethane Foam Block.

Pullout strength is an important indicator of the performance and longevity of pedicle screws and can be heavily influenced by the screw design, the insertion technique and the quality of surrounding bone. The purpose of this study was to investigate the pullout strength of three different pedicle screws inserted using three different strategies and with two different loading conditions. Three pedicle screws with different thread designs (single-lead-thread (SLT) screw, dual-lead-thread (DLT) screw and mixed-single-lead-thread (MSLT) screw) were inserted into a pre-drilled rigid polyurethane foam block using three strategies: (A) screw inserted to a depth of 33.5 mm; (B) screw inserted to a depth of 33.5 mm and then reversed by 3.5 mm to simulate an adjustment of the tulip height of the pedicle screw and (C) screw inserted to a depth of 30 mm. After insertion, each screw type was set up with and without a cyclic load being applied to the screw head prior to the pullout test. To ensure that the normality assumption is met, we applied the Shapiro-Wilk test to all datasets before conducting the non-parametric statistical test (Kruskal-Wallis test combined with pairwise Mann-Whitney-U tests). All screw types inserted using strategy A had a significantly greater pullout strength than those inserted using strategies B and C, regardless of if the screw was pre-loaded with a cyclic load prior to testing. Without the use of the cyclic pre-load, the MSLT screw had a greater pullout strength than the SLT and DLT screws for all three insertion strategies. However, the fixation strength of all screws was reduced when pre-loaded before testing, with the MSLT screw inserted using strategy B producing a significantly lower pullout strength than all other groups (p < 0.05). In contrast, the MSLT screw using insertion strategies A and C had a greater pullout strength than the SLT and DLT screws both with and without pre-loading. In conclusion, the MSLT pedicle screw exhibited the greatest pullout strength of the screws tested under all insertion strategies and loading conditions, except for insertion strategy B with a cyclic pre-load. While all screw types showed a reduced pullout strength when using insertion strategy B (screw-out depth adjustment), the MSLT screw had the largest reduction in pullout strength when using a pre-load before testing. Based on these findings, during the initial screw insertion, it is recommended to not fully insert the screw thread into the bone and to leave a retention length for depth adjustment to avoid the need for screw-out adjustment, as with insertion strategy B.

Spinal metastases from non-small cell lung cancer - Is surgical extent enough by following suggestions of the Tomita and Tokuhashi scores?

BACKGROUND/OBJECTIVE: The Tomita, revised Tokuhashi and Tokuhashi lung scores are commonly used tools to predict the survival of patients with spinal metastases and to guide decisions regarding surgical treatment. These prognostic scores, however, tend to underestimate the prognosis of patients with lung cancer. We examined surgical outcome and hopefully provide a more accurate reference for management. METHODS: The consistency between predicted and actual survival was examined using the Tomita and Tokuhashi scores. Various factors that may influence survival were analyzed. Primary outcomes were overall survival (OS) and progression-free survival (PFS), defined as the ambulatory time after the initial surgery. Secondary outcomes included reoperation events, blood loss, and hospitalization days. RESULTS: One hundred seventy-two patients were enrolled. Correct survival predictions were made for 28%, 42%, and 56% with the Tomita, revised Tokuhashi, and Tokuhashi lung scores, respectively. The Tokuhashi lung scores underestimated OS by 35%-40%. Body mass index ≥20, systemic treatment-naïve, good general condition, the use of denosumab, and adenocarcinoma were found to positively affect OS and PFS. There was no significant difference between palliative decompression and excisional surgery regarding OS and PFS. CONCLUSION: Patients with spinal metastases from lung cancer had better prognosis than that predicted by the Tomita and Tokuhashi scores. Spine surgeons should acknowledge this discrepancy and treat these patients with at least the aggressiveness suggested. Patients with adenocarcinoma, amenable to target therapy, denosumab, good general condition, systemic treatment-naïve are better candidates for surgery. Those with cachexic status and unresectable visceral metastases are worse candidates.

Delay of Surgery for Spinal Metastasis due to the COVID-19 Outbreak Affected Patient Outcomes.

OBJECTIVE: The present study is to analyze the effects of the coronavirus disease 2019 (COVID 2019) outbreak and the subsequent lockdown on the outcomes of spinal metastasis patients. METHODS: The study was a retrospective analysis of data from a prospective cohort study. All patients underwent surgical intervention for spinal metastases between January 2019 and December 2021 and had at least 3 months of postoperative follow-up. The primary outcome was overall mortality during the 4 different stages (pre-COVID-19 era, COVID-19 pandemic except in Taiwan, national lockdown, lifting of the lockdown). The secondary outcomes were the oncological severity scores, medical/surgical accessibility, and patient functional outcome during the 4 periods as well as survival/mortality. RESULTS: A total of 233 patients were included. The overall mortality rate was 41.20%. During the Taiwan lockdown, more patients received palliative surgery than other surgical methods, and no total en bloc spondylectomy was performed. The time from surgeon visit to operation was approximately doubled after the COVID-19 outbreak in Taiwan (75.97, 86.63, 168.79, and 166.91 hours in the 4 periods, respectively). The estimated survival probability was highest after the national lockdown was lifted and lowest during the lockdown. In the multivariate analysis, increased risk of mortality was observed with delay of surgery, with emergency surgery having a higher risk with delays above 33 hours, urgent surgery (below 59 and above 111 hours), and elective surgery (above 332 hours). CONCLUSION: The COVID-19 pandemic and related policies have altered daily clinical practice and negatively impacted the survival of patients with spinal metastases.

Applying High-Resolution Impedance Manometry for Detecting Swallowing Change in Anterior Cervical Spine Surgery Patients.

Background: Objectively detecting perioperative swallowing changes is essential for differentiating the reporting of subjective trouble sensations in patients undergoing anterior cervical spine surgery (ACSS). Swallowing indicates the transmission of fluid boluses from the pharynx (velopharynx, oropharynx, and hypopharynx) through the upper esophageal sphincter (UES). Abnormal swallowing can reveal fluid accumulation at the pharynx, which increased the aspiration risk. However, objective evidence is limited. High-resolution impedance manometry (HRIM) was applied for an objective swallowing evaluation for a more detailed analysis. We aimed to elucidate whether HRIM can be used to detect perioperative swallowing changes in patients undergoing ACSS. Methods: Fourteen patients undergoing elective ACSS underwent HRIM with the Dysphagia Short Questionnaire (DSQ, score: 0-18) preoperatively (PreOP), on postoperative at day 1 (POD1), and postoperative at day seven (POD7). We calculated hypopharyngeal and UES variables, including hypopharyngeal mean peak pressure (PeakP) and UES peak pressure, representing their contractility (normal range of PeakP, 69-280 mmHg; peak pressure, 149-548 mmHg). The velopharynx-to-tongue base contractile (VTI) was also calculated (normal range, 300-700 mmHg.s.cm), indicating contractility. The swallowing risk index (SRI) from HRIM combined with four hypopharyngeal parameters, including PeakP, represents the global swallowing function (normal range, 0-11). A higher SRI value indicated higher aspiration. Results: SRI was significantly higher on POD1 (10.88 ± 5.69) than PreOP (6.06 ± 3.71) and POD7 (8.99 ± 4.64). In all patients, PeakP was significantly lower on POD1 (61.8 ± 18.0 mmHg) than PreOP (84.9 ±34.7 mmHg) and on POD7 (75.3 ± 23.4 mmHg). The UES peak pressure was significantly lower on POD1 (80.4 ± 30.0 mmHg) than PreOP (112.9 ± 49.3 mmHg) and on POD7 (105.6 ± 59.1 mmHg). Other variables, including VTI, did not change significantly among the three time points. DSQ scores were 1.36, 3.43, and 2.36 at PreOP, POD1, and POD7 respectively. Conclusions: With similar trends in DSQ and SRI, swallowing was significantly decreased on POD1 because of decreased hypopharyngeal and UES contractility but recovered to the preoperative state on POD7 after ACSS. Applying HRIM is superior to DSQ in detecting mechanisms and monitoring the recovery from swallowing dysfunction. Clinical Trial Registration: The study was registered at ClinicalTrials.gov (NCT03891940).