A Combined Cyto- and Histopathological Diagnostic Approach Reduces Time to Diagnosis and Time to Therapy in First Manifestation of Metastatic Spinal Disease: A Cohort Study.

Malignant spinal lesions (MSLs) are frequently the first manifestation of malignant disease. Spinal care, diagnostic evaluation, and the initiation of systemic therapy are crucial for outcomes in patients (pts) with advanced cancer. However, histopathology (HP) may be time consuming. The additional evaluation of spinal lesions using cytopathology (CP) has the potential to reduce the time to diagnosis (TTD) and time to therapy (TTT). CP and HP specimens from spinal lesions were evaluated in parallel in 61 pts (CP/HP group). Furthermore, 139 pts in whom only HP was performed were analyzed (HP group). We analyzed the TTD of CP and HP within the CP/HP group. Furthermore, we compared the TTD and TTT between the groups. The mean TTD in CP was 1.7 ± 1.7 days (d) and 8.4 ± 3.6 d in HP (p < 0.001). In 13 pts in the CP/HP group (24.1%), specific therapy was initiated based on the CP findings in combination with imaging and biomarker results before completion of HP. The mean TTT in the CP/HP group was 21.0 ± 15.8 d and was significantly shorter compared to the HP group (28.6 ± 23.3 d) (p = 0.034). Concurrent CP for MSLs significantly reduces the TTD and TTT. As a result, incorporating concurrent CP for analyzing spinal lesions suspected of malignancy might have the potential to enhance pts' quality of life and prognosis in advanced cancer. Therefore, we recommend implementing CP as a standard procedure for the evaluation of MSLs.

Cavernous Malformations and Hemangioblastomas of the Spinal Cord Show Distinct Differences in Clinical Course - A Retrospective Single-Center Analysis of 112 Patients.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: Cavernous malformations (CMs) and hemangioblastomas (HBs) of the spinal cord exhibit distinct differences in histopathology but similarities in the neurological course. The aim of our study was to analyze the clinical differences between the vascular pathologies and a benign tumor of the spinal cord in a perioperative situation. METHODS: We performed a retrospective analysis of patients who had undergone surgery for lesions in the spinal cord between 1984 and 2015. Patients were screened for CMs and HBs as the primary inclusion criteria. General patient information, surgical data, and disease-specific data were collected from the records. Cooper-Epstein scores for clinical symptoms were evaluated preoperatively, at discharge, and at the 6-month follow-up. RESULTS: A total of 112 patients were included, of which 46 had been diagnosed with CMs and 66 with HBs. Patients with CMs often demonstrated more preoperative neurological deterioration compared to those with HBs (P < .05); accordingly, in took longer to diagnose HBs. Complete resection was possible for 96.8% of all patients with CMs and 90% of those with HBs. At the 6-month follow-up, patients with HBs more often presented with persisting neurologic impairment of the upper extremities compared to the CM patients (P < .001). CONCLUSION: CMs and HBs of the spinal cord have similarities but also exhibit significant differences in neurological presentation and perioperative course. Surgical therapy is the treatment of choice for symptomatic lesions, and complete surgical resection is possible in the majority of cases for both entities. Neurologic outcomes are usually favorable, although patients with HBs retain neurologic deficits more often.

[Perioperative management after traumatic paraplegia : Avoiding complications]. / Perioperatives Management nach traumatischer Querschnittslähmung : Komplikationen vermeiden.

This article describes the current status of modern treatment options for traumatic spinal cord injuries with a particular focus on the perioperative phase. Along with a recognition of age-related specific features that can impact successful treatment of spinal injuries, prompt interdisciplinary treatment while adhering to the "time is spine" principle is of high importance. By considering this approach and using modern diagnostic and surgical techniques, successful surgical treatment can be achieved while taking into account individual characteristics, such as reduced bone quality, accompanying injuries as well as oncological and inflammatory rheumatic comorbidities. The preventive and treatment strategies for frequently occurring complications in the management of traumatic spinal cord injuries are presented. By considering case-specific factors, utilizing modern surgical techniques, avoiding or promptly treating typical complications and initiating interdisciplinary treatment, crucial groundwork for a successful long-term treatment of this highly debilitating and life-altering injury can be established in the perioperative phase.

Can You Feel it? - Correlation Between Intraoperatively Perceived Bone Quality and Objectively Measured Bone Mineral Density.

STUDY DESIGN: clinical study. OBJECTIVES: Loosening of pedicle screws is a frequent complication in patients with osteoporosis. The indication for additional stabilization, such as cement augmentation, is more often based on the subjective intraoperative feeling of the surgeon than on a preoperative bone mineral density (BMD) measurement. Aim was to evaluate the correlation of the intraoperative perceived bone quality in comparison to the objectively measured BMD. METHODS: A total of 62 patients undergoing dorsal stabilization using pedicle screws at a level-1 trauma center were analyzed. The preoperative CT scan measured each instrumented vertebra's pedicle size and BMD. During the surgery, the perceived screw stability was graded by the respective surgeon for each screw. RESULTS: 204 vertebral bodies were evaluated. Looking at all implanted screws a significant correlation between the measured BMD and the perceived screw stability was found (Resident r = .450; R2 = .202; P < .001/Attending r = .364; R2 = .133; P < .001), but there was no significant correlation in the osteoporotic patients (Resident P = .148 / Attending P = .907). The evaluation of the screws implanted in osteoporotic vertebrae showed that the surgeons considered a total of 31% of these screws to be sufficiently stable. CONCLUSIONS: There was no significant correlation between the measured BMD and the perceived pedicle screw stability in the group with osteopenic / osteoporotic bone (<100 mg/cm³). The results indicate that it is not possible to reliably determine the bone quality and the resulting screw stability in patients with reduced BMD. The preoperative measurement of the BMD should become a crucial part of preoperative planning.

[Does navigation still have a value in trauma surgery?] / Hat die Navigation in der Traumatologie noch einen Stellenwert?

BACKGROUND: Navigation systems are supposed to increase precision and support surgeons while they perform certain interventions. 2D, or nowadays 3D, systems are used in image-based approaches. Image-free navigation uses 3D printing. INDICATIONS: There are several studies on navigation procedures in trauma surgery. In contrast to limb surgery, the use of 3D navigation in pelvic and spine surgery is already well established. Navigation is especially regularly used to treat fractures of the posterior pelvic ring and for posterior stabilization of the cervical spine. REQUIREMENTS: To be able to utilize navigation systems optimally, the learning curve should be completed, and the technique should be used regularly. In addition, the surgeon should know the surgical technique without navigation in order to recognize potential errors of the navigation. ADVANTAGES AND DISADVANTAGES: Advantages include increased patient safety, reduction in radiation exposure and less invasive surgical procedures. However, among other disadvantages, initial costs are high.

Surgical Site Cytology to Diagnose Spinal Lesions.

Patients with new-onset malignant spinal lesions often have an urgent need for local spine intervention and systemic therapy. For optimal management, it is crucial to diagnose the underlying disease as quickly and reliably as possible. The aim of our current study was to determine the feasibility, sensitivity, specificity, and diagnostic certainty of complementary cytological evaluation of spinal lesions suspected of malignancy. In 44 patients, we performed histopathological biopsies and in parallel cytologic preparations from the malignant site. Cytological smears were prepared and stained for May-Grunwald and Giemsa. Bone biopsies were histopathologically analyzed according to the existing standard-of-care practices. In 42 of 44 cases (95%), a cytological sample was successfully obtained. In 40 cases (95.2%, Cohen's kappa: 0.77), the cytological diagnosis agreed with the histological diagnosis regarding the identification of a malignant lesion. This resulted in a sensitivity of 97% and a specificity of 80% as well as a diagnostic safety of 95%. Cytological analysis in the context of spinal surgery proved sufficient to establish a diagnosis of malignancy or its exclusion, expanding the existing diagnostic spectrum. Furthermore, implementation of this process as a routine clinical diagnostic might shorten the time to diagnosis and improve the treatment of this vulnerable patient group.

Outcome after Posterior Vertebral Column Resection in Patients with Severe Osteoporotic Fractures-A Retrospective Analysis from Two Centers.

Background and Objectives: In osteoporotic fractures of the spine with resulting kyphosis and threatening compression of neural structures, therapeutic decisions are difficult. The posterior vertebral column resection (pVCR) has been described by different authors as a surgical treatment in a single-stage posterior procedure. The aim of this study is to evaluate midterm outcomes of patients treated by pVCR due to severe osteoporotic fractures. Materials and Methods: Retrospective data analysis of all the patients treated for osteoporotic fractures by pVCR from 2012-2020 at two centers was performed. Demographic data, visual analog scale (VAS), Frankel scale (FS), Karnofsky performance status (KPS), radiological result and spinal fusion rates were evaluated. Results: A total of 17 patients were included. The mean age was 70 ± 10.2 y. The mean VAS decreased significantly from 7.7 ± 2.8 preoperatively to 3.0 ± 1.6 at last follow-up (p < 0.001) and the segmental kyphosis decreased from 29.4 ± 14.1° to 7.9 ± 8.0° (p < 0.001). The neurologic function on the FS did not worsen in any and improved in four of the patients. The median KPS remained stable over the whole observation period (70% vs. 70%). Spinal fusion was observed in nine out of nine patients who received CT follow-up >120 days after index surgery. Conclusions: This study showed that pVCR is a safe surgical technique with few surgical complications and no neurological deterioration considering the cohort. The patients' segmental kyphosis and VAS improved significantly, while the KPS remained stable.

The Hamburg Spondylodiscitis Assessment Score (HSAS) for Immediate Evaluation of Mortality Risk on Hospital Admission.

(1) Background: Patients with spondylodiscitis often present with unspecific and heterogeneous symptoms that delay diagnosis and inevitable therapeutic steps leading to increased mortality rates of up to 27%. A rapid initial triage is essential to identify patients at risk for a complicative disease course. We therefore aimed to develop a risk assessment score using fast available parameters to predict in-hospital mortality of patients admitted with spondylodiscitis. (2) Methods: A retrospective data analysis of 307 patients with spondylodiscitis recruited from 2013 to 2020 was carried out. Patients were grouped according to all-cause mortality. Via logistic regression, individual patient and clinical characteristics predictive of mortality were identified. A weighted sum score to estimate a patient's risk of mortality was developed and validated in a randomly selected subgroup of spondylodiscitis patients. (3) Results: 14% of patients with spondylodiscitis died during their in-hospital stay at a tertiary center for spinal surgery. Univariate and logistic regression analyses of parameters recorded at hospital admission showed that age older than 72.5 years, rheumatoid arthritis, creatinine > 1.29 mg/dL and CRP > 140.5 mg/L increased the risk of mortality 3.9-fold, 9.4-fold, 4.3-fold and 4.1-fold, respectively. S. aureus detection increased the risk of mortality by 2.3-fold. (4) Conclusions: The novel Hamburg Spondylodiscitis Assessment Score (HSAS) shows a good fit identifying patients at low-, moderate-, high- and very high risk for in hospital mortality on admission (AUC: 0.795; p < 0.001). The implementation of the HSAS into clinical practice could ease identification of high-risk patients using readily available parameters alone, improving the patient's safety and outcome.

Impact of Screw Diameter on Pedicle Screw Fatigue Strength-A Biomechanical Evaluation.

OBJECTIVE: Loosening of pedicle screws is a frequently observed complication in spinal surgery. Because additional stabilization procedures such as cement augmentation or lengthening of the instrumentation involve relevant risks, optimal stability of the primarily implanted pedicle screw is of essential importance. The aim of the present study was to investigate the effect of increasing the screw diameter on pedicle screw stability. METHODS: A total of 10 human cadaveric vertebral bodies (L4) were included in the present study. The bone mineral density was evaluated using quantitative computed tomography and the pedicle diameter using computed tomography. The vertebrae underwent instrumentation using 6.0-mm × 45-mm pedicle screws on 1 side and screws with the largest possible diameter (8-10-mm × 45-mm) on the other side. Fatigue testing was performed by applying a cyclic loading (craniocaudal sinusoidal 0.5 Hz) with increasing peak force (100 N + 0.1 N/cycle) until screw head displacement of 5.4 mm was reached. RESULTS: The mean fatigue load was 334 N for the 6-mm diameter screws and was increased significantly to 454 N (+36%) for the largest possible diameter screws (P < 0.001). With an increase in the fatigue load by 52%, this effect was even more pronounced in vertebrae with reduced bone density (bone mineral density <120 mg/cm3; n = 7; P < 0.001). The stiffness of the construct was significantly greater in the largest diameter screw group compared with the standard screw group during the entire testing period (start, P < 0.001; middle, P < 0.001; end, P = 0.009). CONCLUSIONS: Increasing the pedicle screw diameter from a standard 6-mm screw to the largest possible diameter (8-10 mm) led to a significantly greater fatigue load.

Posterior vertebral column resection as a safe procedure leading to solid bone fusion in metastatic epidural spinal cord compression.

OBJECTIVE: Cancer is one of the leading causes of death and greatly decreases a patient's quality of life. Vertebral metastases often lead to epidural spinal cord compression (ESCC) requiring surgical therapy. It has previously been shown that in patients with metastatic ESCC (MESCC), a surgical intervention leads to an improved outcome. Although the treatment paradigms in spinal metastases have changed and separation surgery followed by stereotactic radiosurgery is considered the best strategy, there are still cases in which 360° decompression with stabilization is indicated. In these patients, a proper bone fusion should be the treatment goal to guarantee good clinical results in extended survival times through progressions in oncological therapies. The aim of this study was to examine the safety and feasibility of posterior vertebral column resection (pVCR) in everyday clinical practice, achievement of bone fusion, and midterm outcome in patients with MESCC. METHODS: All patients treated with pVCR due to MESCC between 2013 and 2020 were enrolled in this observational single-center study. Demographics, outcome parameters, numeric rating scale (NRS) score, Frankel grade, and Karnofsky Performance Scale (KPS) score were evaluated. Radiological images routinely acquired during follow-up were reviewed and screened for the presence of bone fusion. RESULTS: Sixty-six patients were treated by eight surgeons. The mean follow-up period was 549 ± 739 days. At baseline, the average age was 64.4 ± 10.9 years. Reported NRS scores (preoperative 6.2 ± 1.7 vs postoperative 3.4 ± 1.6) and segmental kyphosis as measured on sagittal CT images (preoperative 13.5° ± 8.6° vs postoperative 3.8° ± 5.4°) decreased significantly (p < 0.001). In only 2 patients (3%), the Frankel grade worsened postoperatively, whereas in 12 patients (18.2%) an improvement was documented. The KPS score remained constant during the observation period (preoperative 73.2% ± 18.2% vs 78.3% ± 18% at last follow-up). Bone fusion was observed in 26 patients (86.7%) receiving CT more than 100 days after the index surgery. CONCLUSIONS: pVCR is a reliable surgical technique in daily clinical practice, which proves to be beneficial in terms of short- as well as midterm outcome, as judged by the KPS and NRS. The overall improvement in the Frankel grade shows patient safety. A bone fusion was observed regularly in oncological patients undergoing pVCR. The authors therefore conclude that pVCR is a safe, fast, and efficient strategy to achieve stability and pain relief by achievement of bone fusion in cancer patients.

Intraoperative blood loss in oncological spine surgery.

OBJECTIVE: Intraoperative blood loss in patients undergoing oncological spine surgery poses a major challenge for vulnerable patients. The goal of this study was to assess how the surgical procedure, tumor type, and tumor anatomy, as well as anesthesiological parameters, affect intraoperative blood loss in oncological spine surgery and to use this information to generate a short preoperative checklist for spine surgeons and anesthesiologists to identify patients at risk for increased intraoperative blood loss. METHODS: The authors performed a retrospective analysis of 430 oncological patients who underwent spine surgery between 2013 and 2018 at the university medical spine center. Enrolled patients had metastatic tumor of the spine requiring surgical decompression of neural structures and/or stabilization including tumor biopsy using an open, percutaneous, and/or combined dorsoventral approach. Patients requiring vertebro- and kyphoplasty or biopsy only were excluded. Statistical analyses performed included a multiple linear regression analysis. RESULTS: The mean intraoperative blood loss in the study patient cohort was 1176 ± 1209 ml. In total, 33.8% of patients received intraoperative red blood cell transfusions. The statistical analyses showed that tumor histology indicating myeloma, operative procedure length, epidural spinal cord compression (ESCC) score, tumor localization, BMI, and surgical strategy were significantly associated with increased intraoperative blood loss or risk of needing allogeneic blood transfusions. Anesthesiological parameters such as the American Society of Anesthesiologists (ASA) Physical Status classification score were not associated with blood loss. Multiple linear regression analysis demonstrated good predictive value (r = 0.437) for a five-item preoperative checklist to identify patients at risk for high intraoperative blood loss. CONCLUSIONS: The analyses performed in this study demonstrated key factors affecting intraoperative blood loss and showed that a simple preoperative checklist including these factors can be used to identify patients undergoing surgery for metastatic spine tumors who are at risk for increased intraoperative blood loss. ABBREVIATIONS: ABT = allogeneic blood transfusion; ASA = American Society of Anesthesiologists; ESCC = epidural spinal cord compression; KW = Kruskal-Wallis; MET = metabolic equivalent of task; RBC = red blood cell.

Cortical threaded pedicle screw improves fatigue strength in decreased bone quality.

PURPOSE: Inadequate anchoring of pedicle screws in vertebrae with poor bone quality is a major problem in spine surgery. The aim was to evaluate whether a modified thread in the area of the pedicle could significantly improve the pedicle screw fatigue strength. METHODS: Fourteen human cadaveric vertebral bodies (L2 and L3) were used for in vitro testing. Bone density (BMD) was determined by quantitative computed tomography. Vertebral bodies were instrumented by standard pedicle screws with a constant double thread on the right pedicle and a partial doubling of the threads-quad thread-(cortical thread) in the area of the pedicle on the left pedicle. Pulsating sinusoidal, cyclic load (0.5 Hz) with increasing peak force (100 N + 0.1 N/cycles) was applied orthogonal to the screw axis. The baseline force remained constant (50 N). Fatigue test was terminated after exceeding 5.4-mm head displacement (~ 20° screw tilting). RESULTS: The mean fatigue load at failure was 264.9 N (1682 cycles) for the standard screws and was increased significantly to 324.7 N (2285 cycles) by the use of cortical threaded screws (p = 0.014). This effect is particularly evident in reduced BMD (standard thread 241.2 N vs. cortical thread 328.4 N; p = 0.016), whereas in the group of vertebrae with normal BMD no significant difference could be detected (standard thread 296.5 N vs. cortical thread 319.8 N; p = 0.463). CONCLUSIONS: Compared to a conventional pedicle screw, the use of a cortical threaded pedicle screw promises superior fatigue load in vertebrae with reduced bone quality.

Rescue Augmentation: Increased Stability in Augmentation After Initial Loosening of Pedicle Screws.

STUDY DESIGN: Biomechanical study. OBJECTIVES: Failure of pedicle screws is a major problem in spinal surgery not only postoperatively, but also intraoperatively. The aim of this study was to evaluate whether cement augmentation may restore mounting of initially loosened pedicle screws. METHODS: A total of 14 osteoporotic or osteopenic human cadaveric vertebral bodies (L2)-according to quantitative computed tomography (QCT)-were instrumented on both sides by conventional pedicle screws and cement augmented on 1 side. In vitro fatigue loading (cranial-caudal sinusoidal, 0.5 Hz) with increasing peak force (100 N + 0.1 N/cycles) was applied until a screw head displacement of 5.4 mm (∼20°) was reached. After loosening, the nonaugmented screw was rescue augmented, and fatigue testing was repeated. RESULTS: The fatigue load reached 207.3 N for the nonaugmented screws and was significantly (P = .009) exceeded because of initial cement augmentation (300.6 N). The rescue augmentation after screw loosening showed a fatigue load of 370.1 N which was significantly higher (P < .001) compared with the nonaugmented screws. The impact of bone density on fatigue strength decreased from the nonaugmented to the augmented to the rescue-augmented screws and shows the greatest effect of cement augmentation on fatigue strength at low bone density. CONCLUSIONS: Rescue augmentation leads to similar or higher fatigue strengths compared with those of the initially augmented screws. Therefore, the cement augmentation of initially loosened pedicle screws is a promising option to restore adequate screw stability.

Reduced cement volume does not affect screw stability in augmented pedicle screws.

PURPOSE: Cement augmentation of pedicle screws is able to improve screw anchorage in osteoporotic vertebrae but is associated with a high complication rate. The goal of this study was to evaluate the impact of different cement volumes on pedicle screw fatigue strength. METHODS: Twenty-five human vertebral bodies (T12-L4) were collected from donors between 73 and 97 years of age. Bone density (BMD) was determined by quantitative computed tomography. Vertebral bodies were instrumented by conventional pedicle screws, and unilateral cement augmentation was performed. Thirteen vertebrae were augmented with a volume of 1 ml and twelve with a volume of 3 ml bone cement. A fatigue test was performed using a cranial-caudal sinusoidal, cyclic load (0.5 Hz) with increasing compression force (100 N + 0.1 N/cycles). RESULTS: The load to failure was 183.8 N for the non-augmented screws and was increased significantly to 268.1 N (p < 0.001) by cement augmentation. Augmentation with 1 ml bone cement increased the fatigue load by 41% while augmentation with 3 ml increased the failure load by 51% compared to the non-augmented screws, but there was no significant difference in fatigue loads between the specimens with screws augmented with 1 ml and screws augmented with 3 ml of bone cement (p = 0.504). CONCLUSION: Cement augmentation significantly increases pedicle screw stability. The benefit of augmentation on screw anchorage was not significantly affected by reducing the applied volume of cement from 3 ml to 1 ml. Considering the high risk of cement leakage during augmentation, we recommend the usage of a reduced volume of 1 ml bone cement for each pedicle screw. These slides can be retrieved under Electronic Supplementary Material .

Preclinical Quantification of Prostate Cancer-Associated Vascular Alterations in the Bone Microenvironment in vivo.

INTRODUCTION: Prostate cancer has a special predilection to form bone metastases. Despite the known impact of the microvascular network on tumour growth and its dependence on the organ-specific microenvironment, the characteristics of the tumour vasculature in bone remain unknown. METHODS: The cell lines LNCaP, DU145, and PC3 were implanted into the femurs of NSG mice to examine the microvascular properties of prostate cancer in bone. Tumour growth and the functional and morphological alterations of the microvasculature were analysed for 21 days in vivo using a transparent bone chamber and fluorescence microscopy. RESULTS: Vascular density was significantly lower in tumour-bearing bone than in non-tumour-bearing bone, with a marked loss of small vessels. Accelerated blood flow velocity led to increased volumetric blood flow per vessel, but overall perfusion was not affected. All of the prostate cancer cell lines had similar vascular patterns, with more pronounced alterations in rapidly growing tumours. Despite minor differences between the prostate cancer cell lines associated with individual growth behaviours, the same overall pattern was observed and showed strong similarity to that of tumours growing in soft tissue. DISCUSSION: The increase in blood flow velocity could be a specific characteristic of prostate cancer or the bone microenvironment.

Of Cestodes and Men: Surgical Treatment of a Spinal Hydatid Cyst.

BACKGROUND: The cestode Echinococcus granulosus causes hydatid disease. In addition to manifestations in the liver and lung, it can lead to cystic lesions in the spine. CASE DESCRIPTION: We report a 42-year-old male patient with primary hydatid disease in the eighth thoracic vertebra. The only clinical symptom was chronic back pain. Although laboratory findings were normal, imaging displayed lytic destruction that raised the suspicion of a metastatic disease. Diagnostics of the thoraces and abdomen did not reveal other pathologic abnormalities. Follow-up magnetic resonance imaging (MRI) depicted a progressive compression of the spinal cord and inhomogeneous structure in the fat-suppressed sequences. Because the Jamshidi biopsy was inconclusive, the tumor board recommended surgery. Dorsal decompression, spondylodesis of T6-T10, and vertebral column resection of T8 with complete cyst removal were performed. The resected vertebrae showed a mucous-like lesion with white granular tissue interfusing the whole vertebral body. A pathologic examination and enzyme-linked immunosorbent assay confirmed E. granulosus. Thus chemotherapy with albendazole was initiated. A follow-up MRI of the whole spine confirmed complete remission and found no additional resettlements. The patient's back pain was resolved without neurologic deficits. CONCLUSIONS: For lytic manifestations of the vertebral column, hydatid cysts should be considered a differential diagnosis in addition to malignant metastasis, tuberculosis, and osteomyelitis. Thorough surgical resection and strict follow-up are necessary.

[Dorsal stabilization of C1/C2 modified according to Goel-Harms with C1 pedicle screws]. / Dorsale Stabilisation der Halswirbelkörper HWK1/HWK2 modifiziert nach Goel-Harms mit HWK-1-Pedikelschrauben.

OBJECTIVE: Stabilization of the atlantoaxial transition by an alternative screw position in C1. INDICATIONS: Instabilities C1/C2 due to inflammation, tumor or trauma. CONTRAINDICATIONS: Presence of a very small pedicle of C1. Variations in the course of the vertebral arteries. SURGICAL TECHNIQUE: The midline approach to the upper cervical spine is used for the modified instrumentation of C1 with pedicle screws instead of Harms screws and for the unaltered instrumentation of C2. Depending on the indication, dorsal spondylodesis is performed by opening the laminae and attaching ceramic bone substitute material. POSTOPERATIVE MANAGEMENT: In mobile patients, additional immobilisation with a soft collar is recommended for 6 weeks. Full recovery is given 3-4 months after surgery. RESULTS: From January 2017 to September 2018, 21 stabilizations of the atlantoaxial transition were performed. The mean age was 72.52 ± 15.45 years. A total of 42 screws were placed in C1. In all, 21 (50%) C1 pedicle screwscould be placed, and in other 21 cases Harms screws were used. Complications were seen in 3 patients. Overall, considering the contraindications, the instrumentation of C1 with pedicle screws appears as a safe alternative to instrumentation with Harms screws.

The bone microenvironment promotes tumor growth and tissue perfusion compared with striated muscle in a preclinical model of prostate cancer in vivo.

BACKGROUND: Prostate cancer-related morbidity is associated with its preferential spread to the bone. Although the molecular interactions between the bone microenvironment and cancer cells have been researched extensively, the relevance of the microvascular properties of prostate cancer bone metastases remains largely unknown. Most preclinical studies focusing on microvascular analyses are based on heterotopic tumor implantation, whereas the impact of the microenvironment on site-specific growth behavior and angiogenesis is rarely addressed. METHODS: The microvascular changes associated with tumor growth in bone and soft tissue were characterized by implanting single cell suspensions of LnCap, Du145, and Pc3 cells into the femur (femur window) or striated muscle (dorsal skinfold chamber) of NSG mice. Tumor growth and the local microvasculature were analyzed for 21 days using intravital fluorescence microscopy. RESULTS: The results showed a higher engraftment of tumor cells in bone than in striated muscle associated with accelerated growth of LnCap cells and Pc3 cells. Permeability, blood flow, and tissue perfusion rates were greater in bone than in striated muscle. Du145 cells showed similar growth behavior in both tissues with similar vascular properties. The bone microenvironment facilitated tumor engraftment and growth. Increased microvascular density in striated muscle led to a higher tumor burden during early growth, whereas the increased perfusion promoted later prostate cancer growth in bone. CONCLUSIONS: Monitoring prostate cancer microcirculation in bone and soft tissue may be useful to evaluate the organ-specific efficacy of new treatments.

Safety and Efficacy of Single-Stage versus 2-Stage Spinal Fusion via Posterior Instrumentation and Anterior Thoracoscopy: A Retrospective Matched-Pair Cohort Study with 247 Consecutive Patients.

OBJECTIVE: Posterior-anterior spondylodesis is often used to stabilize the spine in various pathologies. The anterior procedure is often performed via thoracoscopy. It is unclear whether the anterior procedure should be performed immediately after posterior instrumentation or after the patient has convalesced. This retrospective study compared perioperative safety and morbidity in 1-stage versus 2-stage posterior-anterior fusion surgery with a thoracoscopic anterior approach. METHODS: All consecutive patients who underwent surgery for posterior-anterior spinal stabilization from 2006 to 2013 were included. American Society of Anesthesiologists score, preoperative and postoperative laboratory values, operation duration, blood loss, intensive care unit stay, pain, postoperative hospital stay, perioperative complications, and preoperative and postoperative Eastern Cooperative Oncology Group and Frankel scores were assessed. A subset of the cohort was selected by propensity score matching to eliminate possible selection bias. RESULTS: There were 247 patients who underwent 1-stage (n = 104) or 2-stage (n = 143) stabilization with thoracoscopic fusion. Spinal pathologies were fracture, malignancy, pyogenic spondylodiscitis, degenerative spinal disorders, and failed previous surgery. One-stage and 2-stage procedures were similar in terms of preoperative, surgical, and postoperative variables, including complication rates, except that the 1-stage procedure was associated with greater pain 2 days after surgery and shorter hospital stay. The propensity score-matched cohort of 64 pairs yielded similar results with only 1-stage patients showing elevated visual analog scale score on postoperative day 2 (3.8 vs. 2.4, P = 0.043). CONCLUSIONS: One-stage stabilization was as safe as 2-stage stabilization and associated with shorter hospitalization. Greater pain after the 1-stage procedure, which resolved 30 days after surgery, reflects the fact that 2-stage patients already had pain relief when they underwent thoracoscopy.

In vivo functional and morphological characterization of bone and striated muscle microcirculation in NSG mice.

Organ-specific microcirculation plays a central role in tumor growth, tumor cell homing, tissue engineering, and wound healing. Mouse models are widely used to study these processes; however, these mouse strains often possess unique microhemodynamic parameters, making it difficult to directly compare experiments. The full functional characterization of bone and striated muscle microcirculatory parameters in non-obese diabetic-severe combined immunodeficiency/y-chain; NOD-Prkds IL2rg (NSG) mice has not yet been reported. Here, we established either a dorsal skinfold chamber or femur window in NSG mice (n = 23), allowing direct analysis of microcirculatory parameters in vivo by intravital fluorescence microscopy at 7, 14, 21, and 28 days after chamber preparation. Organ-specific differences were observed. Bone had a significantly lower vessel density but a higher vessel diameter than striated muscle. Bone also showed higher effective vascular permeability than striated muscle. The centerline velocity values were similar in the femur window and dorsal skinfold chamber, with a higher volumetric blood flow in bone. Interestingly, bone and striated muscle showed similar tissue perfusion rates. Knowledge of physiological microhemodynamic values of bone and striated muscle in NSG mice makes it possible to analyze pathophysiological processes at these anatomic sites, such as tumor growth, tumor metastasis, and tumor microcirculation, as well as the response to therapeutic agents.