Does Intrawound Vancomycin Decrease Postoperative Surgical Site Infection in Spine Surgery: A Retrospective Case-control Study.

STUDY DESIGN: Retrospective Case-Control series. OBJECTIVE: The objective of this study is to define the overall postoperative rate of surgical site infection (SSI) in patients undergoing spine surgery and examine the effects of intrawound Vancomycin on postoperative infection rates. SUMMARY OF BACKGROUND DATA: Surgical site infections (SSI) account for 22% of all health care-associated infections. The use of intrawound Vancomycin in an attempt to reduce the incidence of postoperative SSI has not been sufficiently evaluated in the existing literature. METHODS: All spine surgeries (n=19,081) from our institution were reviewed from 2003 to 2013. All cases of verified SSI were identified from the database. Cases were then matched to controls in a 1:1 fashion based on age, gender, and date of surgery (+/-30 d). Patient demographics, comorbidities, estimated blood loss, duration of surgery, intrawound administration of Vancomycin, and smoking status were evaluated. RESULTS: At total of 316 cases of SSI after spine surgery were identified, representing an infection rate of 1.7%. The mean follow-up for cases and controls was 31.5 and 41.6 months, respectively. OR for intrawound Vancomycin was 0.44 (95% CI 0.23-0.88, P =0.019). OR for BMI greater than 30 was 1.63 (95% CI 1.04-2.56, P =0.03). CONCLUSIONS: In this large cohort of spine surgery patients, administration of intrawound Vancomycin was associated with a significant reduction in postoperative surgical site infections. Further studies are needed to determine appropriate dosing and application as well as long-term safety in spine surgery.

Open-Spaced Ridged Hydrogel Scaffolds Containing TiO2-Self-Assembled Monolayer of Phosphonates Promote Regeneration and Recovery Following Spinal Cord Injury.

The spinal cord has a poor ability to regenerate after an injury, which may be due to cell loss, cyst formation, inflammation, and scarring. A promising approach to treating a spinal cord injury (SCI) is the use of biomaterials. We have developed a novel hydrogel scaffold fabricated from oligo(poly(ethylene glycol) fumarate) (OPF) as a 0.08 mm thick sheet containing polymer ridges and a cell-attractive surface on the other side. When the cells are cultured on OPF via chemical patterning, the cells attach, align, and deposit ECM along the direction of the pattern. Animals implanted with the rolled scaffold sheets had greater hindlimb recovery compared to that of the multichannel scaffold control, which is likely due to the greater number of axons growing across it. The immune cell number (microglia or hemopoietic cells: 50-120 cells/mm2 in all conditions), scarring (5-10% in all conditions), and ECM deposits (Laminin or Fibronectin: approximately 10-20% in all conditions) were equal in all conditions. Overall, the results suggest that the scaffold sheets promote axon outgrowth that can be guided across the scaffold, thereby promoting hindlimb recovery. This study provides a hydrogel scaffold construct that can be used in vitro for cell characterization or in vivo for future neuroprosthetics, devices, or cell and ECM delivery.

Outcomes of Recurrent Mobile Spine Chordomas.

INTRODUCTION: Chordomas of the mobile spine are rare malignant tumors. The purpose of this study was to review the outcomes of treatment for patients with recurrent mobile spine chordomas. METHODS: The oncologic outcomes and survival of 30 patients undergoing treatment of a recurrent mobile spine chordoma were assessed over a 24-year period. The mean follow-up was 3.5 years. RESULTS: In patients presenting with a recurrent mobile spine chordoma, the mean 2- and 5-year overall survival was 73% and 39%, respectively. Enneking appropriate resection trended toward improved overall survival at 5 years (100% vs. 32%, P = 0.24). Those undergoing surgical resection for recurrence had improved metastatic-free survival (hazard ratio 0.29, CI 0.08 to 0.99, P = 0.05). Positive margins were found to be a risk factor of further local recurrence (hazard ratio 7.92, CI 1.02 to 61.49, P = 0.04). Those undergoing nonsurgical management trended toward having an increase in new neurologic deficits (P = 0.09), however, there was no difference in overall complications based on treatment type (P = 0.13). CONCLUSION: Recurrent mobile spine chordoma portends a poor prognosis with an overall survival of less than 40% at 5 years. Surgical resection may help prevent new neurologic deficits and tumor metastasis while en bloc excision with negative surgical margins is associated with improved local recurrence-free survival.

Ultrasonographic Detection and Surgical Retrieval of a Nonmetallic Twinkle Marker in Breast Cancer: Pilot Study.

Purpose To evaluate the short-term safety of a nonmetallic twinkle marker and compare its conspicuity at color Doppler US with that of standard breast biopsy clips and radioactive seeds by using B-mode US in axillary lymph nodes. Materials and Methods This prospective study (November 2020-July 2021) of participants with node-positive breast cancer who completed chemotherapy involved placing a twinkle marker at the time of preoperative radioactive seed localization. A five-point scoring system (1 = easiest, 5 = most difficult) was used to rate the ease of identifying the clip, seed, and twinkle marker on postlocalization sonograms, mammograms, specimen radiographs, and gross pathologic specimens. Descriptive statistics were used. Results Eight women (mean age, 57 years ± 16 [SD]) were enrolled. The median scores for US conspicuity of each device were 3.9 (range, 3.7-5.0) for the radioactive seed, 2.4 (range, 1.0-5.0) for the clip, and 2.0 (range, 1.0-4.3) for the twinkle marker. In six of eight participants, the twinkle marker was the most identifiable at US. The seeds, clips, and twinkle markers were scored "very easy" to identify on seven of eight postlocalization mammograms. The surgeon retrieved all eight twinkle markers 1-3 days after localization. In all 16 interpretations, the seeds, clips, and twinkle markers were rated as very easy to identify on specimen radiographs. The clip was the most difficult device to identify at pathologic examination in all participants, and the twinkle marker was the easiest to identify in seven of eight participants. Conclusion This pilot study demonstrates that the safety and ease of US detection of a twinkling tissue marker may be comparable to a biopsy clip. Keywords: Ultrasonography, US-Doppler, Breast, Localization, Surgery Clinical trial registration no. NCT04674852 © RSNA, 2022.

Surgical management of sacral schwannomas: a 21-year mayo clinic experience and comparative literature analysis.

INTRODUCTION: Sacral and presacral schwannomas are rare, accounting for a minority of spinal schwannomas. We present our institution's experience surgically treating spinal schwannomas and compare it to the literature. METHODS: Data were collected for 27 patients treated surgically for sacral or presacral schwannoma between 1997 and 2018 at all Mayo Clinic locations and 93 patients in the literature. Kaplan-Meier disease-free survival analysis was conducted. Unpaired two-sample t tests and Fisher's exact tests assessed statistical significance between groups. RESULTS: Our patients and those in the literature experienced a similar age at diagnosis (49.9 y/o. vs 43.4 y/o., respectively). Most of our patients (59.3%) reported full recovery from symptoms, while a minority reported partial recovery (33.3%) and no recovery (11.1%). A smaller percentage in the literature experienced full recovery (31.9%) and partial recovery (29.8%) but also no recovery (1.1%). Our patients experienced fewer complications (14.8% versus 25.5%). Disease-free survival curves for all patients showed no significant variation in progression by extent of resection of schwannoma (log-rank P = 0.26). No lesion progression was associated with full or partial symptom improvement (p = 0.044), and female patients were more likely to undergo resection via a posterior approach (p = 0.042). CONCLUSION: Outcomes of patients with sacral or presacral schwannomas vary based on patient demographics, tumor characteristics, symptoms, and surgical treatment. Among the range of symptoms experienced by these patients, the most common is pain. Prognosis improves and overall survival is high when the surgical approach towards sacral schwannomas is prepared and executed appropriately.

Twinkling-guided ultrasound detection of polymethyl methacrylate as a potential breast biopsy marker: a comparative investigation.

Since its first description 25 years ago, color Doppler twinkling has been a compelling ultrasound feature in diagnosing urinary stones. While the fundamental cause of twinkling remains elusive, the distinctive twinkling signature is diagnostically valuable in clinical practice. It can be inferred that if an entity twinkles, it empirically has certain physical features. This work investigates a manipulable polymeric material, polymethyl methacrylate (PMMA), which twinkles and has measurable surface roughness and porosity that likely contribute to twinkling. Comparative investigation of these structural properties and of the twinkling signatures of breast biopsy markers made from PMMA and selected commercially available markers showed how twinkling can improve ultrasound detection of devices intentionally designed to twinkle. While this specific application of detecting breast biopsy markers by twinkling may provide a way to approach an unmet need in the care of patients with breast cancer, this work ultimately provides a platform from which the keys to unlocking the fundamental physics of twinkling can be rigorously explored.

Single-level subject-specific finite element model can predict fracture outcomes in three-level spine segments under different loading rates.

Osteoporosis-related vertebral compression fracture can occur under normal physiological activities. Bone metastasis is another source of vertebral fracture. Different loading rates, either high-energy traumas such as falls or low-energy traumas under normal physiological activities, can result in different fracture outcomes. The aim of the current study was to develop a quantitative computed tomography-based finite element analysis (QCT/FEA) technique for single vertebral bodies to predict fracture strength of three-level spine segments. Developed QCT/FEA technique was also used to characterize vertebral elastic moduli at two loading rates of 5 mm/min, representing a physiologic loading condition, and 12000 mm/min, representing a high-energy trauma. To this end, a cohort of human spine segments divided into three groups of intact, defect, and augmented were mechanically tested to fracture; then, experimental stiffness and fracture strength values were measured. Outcomes of this study showed no significant difference between the elastic modulus equations at the two testing speeds. Areal bone mineral density measured by dual x-ray absorptiometry (DXA/BMD) explained only 53% variability (R2 = 0.53) in fracture strength outcomes. However, QCT/FEA could explain 70% of the variability (R2 = 0.70) in experimentally measured fracture strength values. Adding disk degeneration grading, testing speed, and sex to QCT/FEA-estimated fracture strength values further increased the performance of our statistical model by 14% (adjusted R2 of 0.84 between the prediction and experimental fracture forces). In summary, our results indicated that a single-vertebra model, which is computationally less expensive and more time efficient, is capable of estimating fracture outcomes with acceptable performance (range: 70-84%).

RNA-dependent protein kinase is required for interferon-γ-induced autophagy in MG63 osteosarcoma cells.

Osteosarcoma is a bone tumor that mainly affects children and adolescents. Interferons (IFNs) have been shown to exert antitumor effects in osteosarcoma cells, although the molecular mechanisms have not been fully realized. We investigated IFN-γ actions on osteosarcoma cells. Our results show that IFN-γ induces the accumulation of autophagosomes in osteosarcoma cells. IFN-γ treatment leads to the conversion of autophagy marker light chain 3 (LC3)-I to LC3-II in osteosarcoma cells, and this conversion is accompanied by puncta formation. Also, IFN-γ-mediated induction of autophagosome formation and autophagic flux require RNA-dependent protein kinase (PKR) activity. In addition, our findings show that IFN-γ-mediated osteosarcoma cell death is not dependent on PKR. Our study suggests that IFN-γ has differential effects that lead to induction of cell death and autophagy in osteosarcoma cells. Further evaluation of the IFN-γ-mediated molecular mechanism could lead to improved understanding of and targeted treatment strategies for osteosarcoma.

Comparison of free vascularized fibular flaps and allograft fibular strut grafts to supplement spinopelvic reconstruction for sacral malignancies.

AIMS: Orthopaedic and reconstructive surgeons are faced with large defects after the resection of malignant tumours of the sacrum. Spinopelvic reconstruction is advocated for resections above the level of the S1 neural foramina or involving the sacroiliac joint. Fixation may be augmented with either free vascularized fibular flaps (FVFs) or allograft fibular struts (AFSs) in a cathedral style. However, there are no studies comparing these reconstructive techniques. METHODS: We reviewed 44 patients (23 female, 21 male) with a mean age of 40 years (SD 17), who underwent en bloc sacrectomy for a malignant tumour of the sacrum with a reconstruction using a total (n = 20), subtotal (n = 2), or hemicathedral (n = 25) technique. The reconstructions were supplemented with a FVF in 25 patients (57%) and an AFS in 19 patients (43%). The mean length of the strut graft was 13 cm (SD 4). The mean follow-up was seven years (SD 5). RESULTS: There was no difference in the mean age, sex, length of graft, size of the tumour, or the proportion of patients with a history of treatment with radiotherapy in the two groups. Reconstruction using an AFS was associated with nonunion (odds ratio 7.464 (95% confidence interval (CI) 1.77 to 31.36); p = 0.007) and a significantly longer mean time to union (12 months (SD 3) vs eight (SD 3); p = 0.001) compared with a reconstruction using a FVF. Revision for a pseudoarthrosis was more likely to occur in the AFS group compared with the FVF group (hazard ratio 3.84 (95% CI 0.74 to 19.80); p = 0.109); however, this was not significant. Following the procedure, 32 patients (78%) were mobile with a mean Musculoskeletal Tumor Society Score 93 of 52% (SD 24%). There was a significantly higher mean score in patients reconstructed with a FVF compared with an AFS (62% vs 42%; p = 0.003). CONCLUSION: Supplementation of spinopelvic reconstruction with a FVF was associated with a shorter time to union and a trend towards a reduced risk of hardware failure secondary to nonunion compared with reconstruction using an AFS. Spinopelvic fixation supplemented with a FVF is our preferred technique for reconstruction following resection of a sacral tumour. Cite this article: Bone Joint J 2021;103-B(8):1414-1420.

Teriparatide Treatment Increases Hounsfield Units in the Thoracic Spine, Lumbar Spine, Sacrum, and Ilium Out of Proportion to the Cervical Spine.

STUDY DESIGN: This was a retrospective chart review. OBJECTIVE: The objective of this study was to compare the effect of teriparatide on Hounsfield Units (HU) in the cervical spine, thoracic spine, lumbar spine, sacrum, and pelvis. Second, to correlate HU changes at each spinal level with bone mineral density (BMD) on dual-energy x-ray absorptiometry (DXA). SUMMARY OF BACKGROUND DATA: HU represent a method to estimate BMD and can be used either separately or in conjunction with BMD from DXA. MATERIALS AND METHODS: A retrospective chart review included patients who had been treated with at least 6 months of teriparatide. HU were measured in the vertebral bodies of the cervical, thoracic, and lumbosacral spine and iliac crests. Lumbar and femoral neck BMD as measured on DXA was collected when available. RESULTS: One hundred twenty-five patients were identified for analysis with an average age of 67 years who underwent a mean (±SD) of 22±8 months of teriparatide therapy. HU improvement in the cervical spine was 11% (P=0.19), 25% in the thoracic spine (P=0.002), 23% in the lumbar spine (P=0.027), 17% in the sacrum (P=0.11), and 29% in the iliac crests (P=0.09). Lumbar HU correlated better than cervical HU with BMD as measured on DXA. CONCLUSIONS: Teriparatide increased average HU in the thoracolumbar spine to a proportionally greater extent than the cervical spine. The cervical spine had a higher baseline starting HU than the thoracolumbar spine. Lumbar HU correlated better than cervical and thoracic HU with BMD as measured on DXA.

Three-dimensional surface strain analyses of simulated defect and augmented spine segments: A biomechanical cadaveric study.

While several studies have investigated fracture outcomes of intact vertebrae, fracture properties in metastatically-involved and augmented vertebrae are still far from understood. Consequently, this study was aimed to use 3D digital image correlation (3D-DIC) method to investigate the failure properties of spine segments with simulated metastatic lesions, segments augmented with poly(propylene fumarate) (PPF), and compare the outcomes with intact spines. To this end, biomechanical experiments accompanied by 3D-DIC were performed on spine segments consisting of three vertebrae and two intervertebral discs (IVDs) at loading rates of 0.083 mm/s, mimicking a physiological loading condition, and 200 mm/s, mimicking an impact-type loading condition such as a fall or an accident. Full-field surface strain analysis indicated PPF augmentation reduces the superior/inferior strain when compared with the defect specimens; Presence of a defect in the middle vertebra resulted in shear band fracture pattern. Failure of the superior endplates was confirmed in several defect specimens as the superior IVDs were protruding out of defects. The augmenting PPF showed lower superior/inferior surface strain values at the fast speed as compared to the slow speed. The results of our study showed a significant increase in the fracture force from slow to fast speeds (p = 0.0246). The significance of the study was to determine the fracture properties of normal, pathological, and augmented spinal segments under physiologically-relevant loading conditions. Understanding failure properties associated with either defect (i.e., metastasis lesion) or augmented (i.e., post-treatment) spine segments could potentially provide new insights on the outcome prediction and treatment planning. Additionally, this study provides new knowledge on the effect of PPF augmentation in improving fracture properties, potentially decreasing the risk of fracture in osteoporotic and metastatic spines.

The inhibitory effects of vancomycin on rat bone marrow-derived mesenchymal stem cell differentiation.

OBJECTIVE: The use of intrawound vancomycin powder in spine surgery has been shown to decrease the rate of surgical site infections; however, the optimal dose is unknown. High-dose vancomycin inhibits osteoblast proliferation in vitro and may decrease the rate of solid arthrodesis. Bone marrow-derived mesenchymal stem cells (BMSCs) are multipotent cells that are a source of osteogenesis in spine fusions. The purpose of this study was to determine the effects of vancomycin on rat BMSC viability and differentiation in vitro. METHODS: BMSCs were isolated from the femurs of immature female rats, cultured, and then split into two equal groups; half were treated to stimulate osteoblastic differentiation and half were not. Osteogenesis was stimulated by the addition of 50 µg/mL l-ascorbic acid, 10 mM ß-glycerol phosphate, and 0.1 µM dexamethasone. Vancomycin was added to cell culture medium at concentrations of 0, 0.04, 0.4, or 4 mg/mL. Early differentiation was determined by alkaline phosphatase activity (4 days posttreatment) and late differentiation by alizarin red staining for mineralization (9 days posttreatment). Cell viability was determined at both the early and late time points by measurement of formazan colorimetric product. RESULTS: Viability within the first 4 days decreased with high-dose vancomycin treatment, with cells receiving 4 mg/mL vancomycin having 40%-60% viability compared to the control. A gradual decrease in alizarin red staining and nodule formation was observed with increasing vancomycin doses. In the presence of the osteogenic factors, vancomycin did not have deleterious effects on alkaline phosphatase activity, whereas a trend toward reduced activity was seen in the absence of osteogenic factors when compared to osteogenically treated cells. CONCLUSIONS: Vancomycin reduced BMSC viability and impaired late osteogenic differentiation with high-dose treatment. Therefore, the inhibitory effects of high-dose vancomycin on spinal fusion may result from both reduced BMSC viability and some impairment of osteogenic differentiation.

CT-based structural analyses of vertebral fractures with polymeric augmentation: A study of cadaveric three-level spine segments.

Pathologic vertebral fractures due to metastasis can occur under normal physiologic activities, leading to pain and neurologic deficit. Prophylactic vertebroplasty is a technique used to augment vertebral strength and reduce the risk of fracture. Currently, no technique is available to objectively assess vertebral fracture risk in metastatically-involved vertebral bodies. The aim of the current study was to develop an image-based computational technique to estimate fracture force outcomes during bending. To this end, mechanical testing was performed on intact, simulated defect, PMMA-augmented, and PPF-augmented 3-level spine segments from both sexes under a compression/flexion-type loading condition. The augmentation performance of poly(methyl methacrylate) (PMMA) and poly(propylene fumarate) (PPF) were also evaluated and compared. Cylindrical defects were created in 3-level spine segments with attached posterior elements and ligaments. Using CT images of each segment, a rigidity analysis technique was developed and used for predicting fracture forces during bending. On average, PPF strengthened the segments by about 630 N, resulting in fracture forces similar to those observed in the intact and PMMA-augmented groups. Female spines fractured at about 1150 N smaller force than did male spines. Rigidity analysis, along with age, explained 66% variability in experimental outcomes. This number increased to 74% when vertebral size and age were added to the rigidity analysis as explanatory variables. Both PPF and PMMA similarly increased fracture strength to the level of intact specimens. The results suggest that PPF can be a suitable candidate for augmentation purposes and rigidity analysis can be a promising predicting tool for vertebral fracture forces.

2D phosphorene nanosheets, quantum dots, nanoribbons: synthesis and biomedical applications.

Phosphorene, also known as black phosphorus (BP), is a two-dimensional (2D) material that has gained significant attention in several areas of current research. Its unique properties such as outstanding surface activity, an adjustable bandgap width, favorable on/off current ratios, infrared-light responsiveness, good biocompatibility, and fast biodegradation differentiate this material from other two-dimensional materials. The application of BP in the biomedical field has been rapidly emerging over the past few years. This article aimed to provide a comprehensive review of the recent progress on the unique properties and extensive medical applications for BP in bone, nerve, skin, kidney, cancer, and biosensing related treatment. The details of applications of BP in these fields were summarized and discussed.

Surgical treatment of primary mobile spine chordoma.

BACKGROUND AND OBJECTIVES: Chordomas of the mobile spine (C1-L5) are rare malignant tumors. The purpose of this study was to review the outcome of surgical treatment for patients with primary mobile spine chordomas. METHODS: The oncologic outcomes and survival of 26 patients undergoing surgical resection for a primary mobile spine chordoma were assessed over a 25-year period. The mean follow-up was 12 ± 6 years. RESULTS: The 2-, 5-, and 10-year disease-free survivals were 95%, 61%, and 55%. The local recurrence-free survival was improved in patients receiving en bloc resection with negative margins (83% vs. 35%, p = 0.02) and similar in patients receiving adjuvant radiation therapy (43% vs. 45%, p = 0.30) at 10 years. Debulking of the tumor (hazard ratio [HR] = 6.41, p = 0.01) and a local recurrence (HR = 9.52, p = 0.005) were associated with death due to disease. Complications occurred in 19 (73%) patients, leading to reoperation in 9 (35%) patients; this rate was similar in intralesional and en bloc procedures. CONCLUSION: Surgical resection of mobile spine chordomas is associated with a high rate of complications; however, en bloc resection can provide a hope for cure and appears to confer better oncologic outcomes for these tumors without an increase in complications compared to lesser resections.

Mandibular Defect Reconstitution: A Contaminated Caprine Model of Bone Regeneration.

PURPOSE: Mandibular reconstitution with bioabsorbable scaffolds seems feasible with the application of 3-dimensional printing combined with bioactive proteins. As yet, previous studies have been limited in number of animals and have avoided a contaminated defect. We present a caprine model of mandibular defect bone regeneration with a 3-dimensionally printed bioabsorbable scaffold contaminated with oral secretions and explore the impact of bone morphogenic protein in mandibular bone reconstitution. METHODS: A 3-cm, contaminated mandibular defect was generated in 18 goats and stabilized with 2 mandibular reconstruction plates. An uncoated scaffold was placed in 6 goats, and in the final 6 goats, the scaffold was coated with bone morphogenic protein-2. In 6 goats, the defect was left empty. After 12 weeks, the operative site, scaffold, and adjacent mandible were plasticized, sectioned, and evaluated histologically to assess for bone regeneration. RESULTS: The specimens revealed only focal (average of 5.8% of the scaffold pores) and early bone formation in the scaffold-only group. In the scaffold + bone morphogenic protein-2 group, there was more (average of 51.4% of the pores) bone formation. In the periosteum-only group, the ratio of the bone thickness of the defect to that of the normal bone ranged from 0.16 to 0.78. No major infections occurred. CONCLUSIONS: This caprine model serves as an excellent method to assess reconstructive options for contaminated mandibular deficits. Bone regeneration was documented in a 3-cm contaminated caprine mandibular defect reconstructed with a 3-dimensionally printed synthetic scaffold with or without the addition of bone morphogenic protein-2. Bone morphogenic protein-2 significantly augments bone generation in the synthetic scaffold. Residual mandibular periosteum generated bone. Future studies will focus on optimizing vascularization.

Outcome of Sacropelvic Resection and Reconstruction Based on a Novel Classification System.

BACKGROUND: Sacral tumor resections require a multidisciplinary approach to achieve a cure and a functional outcome. Currently, there is no accepted classification system that provides a means to communicate among the multidisciplinary teams in terms of approach, osseous resection, reconstruction, and acceptable functional outcome. The purpose of this study was to report the outcome of sacral tumor resection based on our classification system. METHODS: In this study, 196 patients (71 female and 125 male) undergoing an oncologic en bloc sacrectomy were reviewed. The mean age (and standard deviation) was 49 ± 16 years, and the mean body mass index was 27.2 ± 6.4 kg/m. The resections included 130 sarcomas (66%). The mean follow-up was 7 ± 5 years. RESULTS: Resections included total sacrectomy (Type 1A: 20 patients [10%]) requiring reconstruction, subtotal sacrectomy (Type 1B: 5 patients [3%]) requiring reconstruction, subtotal sacrectomy (Type 1C: 104 patients [53%]) not requiring reconstruction, hemisacrectomy (Type 2: 29 patients [15%]), external hemipelvectomy and hemisacrectomy (Type 3: 32 patients [16%]), total sacrectomy and external hemipelvectomy (Type 4: 5 patients [3%]), and hemicorporectomy (Type 5: 1 patient [1%]). The disease-specific survival was 66% at 5 years and 52% at 10 years. Based on the classification, the 5-year disease-specific survival was 34% for Type 1A, 100% for Type 1B, 71% for Type 1C, 65% for Type 2, 57% for Type 3, 100% for Type 4, and 100% for Type 5 (p < 0.001). Tumor recurrence occurred in 67 patients, including isolated local recurrence (14 patients), isolated metastatic disease (31 patients), and combined local and metastatic disease (22 patients). At 5 years, the local recurrence-free survival was 77% and the metastasis-free survival was 68%. Complications occurred in 153 patients (78%), most commonly wound complications (95 patients [48%]). Following the procedure, 154 patients (79%) were ambulatory, and the mean Musculoskeletal Tumor Society (MSTS93) score was 60% ± 23%. CONCLUSIONS: Although resections of sacral malignancies are associated with complications, they can be curative in a majority of patients, with a majority of patients ambulatory with an acceptable functional outcome considering the extent of the resection. At our institution, this classification allows for communication between surgical teams and implies a surgical approach, staging, reconstruction, and potential functional outcomes. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Detection of macromolecular inversion-induced structural changes in osteosarcoma cells by FTIR microspectroscopy.

Fourier transform infrared (FTIR) microspectroscopy provides a biochemical fingerprint of the cells. In this study, chemical changes in 143B osteosarcoma cells were investigated using FTIR analysis of cancer cells after their treatment with polymeric invertible micellar assemblies (IMAs) and curcumin-loaded IMAs and compared with untreated osteosarcoma cells. A comprehensive principal component analysis (PCA) was applied to analyze the FTIR results and confirm noticeable changes in cell surface chemical structures in the fingerprint regions of 1480-900 cm-1. The performed clustering shows visible differences for all investigated groups of cancer cells. It is demonstrated that a combination of FTIR microspectroscopy with PCA can be an efficient approach in determining interactions of osteosarcoma cells and drug-loaded polymer micellar assemblies. Graphical abstract.

Outcomes of pregnancy in operative vs. nonoperative adolescent idiopathic scoliosis patients at mean 30-year follow-up.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine whether patients who underwent surgical treatment of adolescent idiopathic scoliosis (AIS) in childhood would have an increased C-section risk in adulthood. Although the impact of scoliosis on future pregnancy and child delivery is a common question for patients and parents, there is limited data regarding pregnancy outcomes following childhood treatment of AIS. METHODS: Between 1975 and 1992, 60 female patients underwent treatment for AIS with bracing, surgery, or observation and had data available regarding obstetrical history in the electronic medical record or in paper charts. In childhood, 28 had nonoperative treatment and 32 had fusion surgery. During the follow-up period, 2 nonoperative patients and 1 operative patient had fusion surgery in adulthood, but after childbearing years. Mean age at latest follow-up was 43 years (CI 38, 48). Meantime to follow-up since childhood treatment was 31 years (CI 26, 35). RESULTS: 29% of nonoperative patients had a C-section with at least one live birth compared to 38% of operative patients (p = 0.464). For surgical patients fused to L3 or lower, 46% required at least one C-section, compared to 32% of patients fused to L2 or higher (p = 0.40). Overall, 33% of the cohort of patients-including those with all scoliosis treatment methods-required at least one C-section, compared to the state weighted C-section rate of 20.5% (p = 0.014). The percentage of patients with operative treatment-including all levels of fusion-requiring at least one C-section was statistically different than the weighted state C-section rate (p = 0.020). CONCLUSION: In this long-term cohort of 60 US scoliosis patients, childhood operative fusion treatment was associated with a statistically significant increased incidence of C-section compared to the state incidence at both the patient level and the delivery level. LEVEL OF EVIDENCE: III, comparative cohort study.

An Objective and Reliable Method for Identifying Sarcopenia in Lumbar Spine Surgery Patients: Using Morphometric Measurements on Computed Tomography Imaging.

STUDY DESIGN: A retrospective observational study. PURPOSE: Establish a quantifiable and reproducible measure of sarcopenia in patients undergoing lumbar spine surgery based on morphometric measurements from readily available preoperative computed tomography (CT) imaging. OVERVIEW OF LITERATURE: Sarcopenia-the loss of skeletal muscle mass-has been linked with poor outcomes in several surgical disciplines; however, a reliable and quantifiable measure of sarcopenia for future assessment of outcomes in spinal surgery patients has not been established. METHODS: A cohort of 90 lumbar spine fusion patients were compared with 295 young, healthy patients obtained from a trauma da¬tabase. Cross-sectional vertebral body (VB) area, as well as the areas of the psoas and paravertebral muscles at mid-point of pedicles at L3 and L4 for both cohorts, was measured using axial CT imaging. Total muscle area-to-VB area ratio was calculated along with intraclass correlation coefficients for interobserver and intraobserver reliability. Finally, T-scores were calculated to help identify those patients with considerably diminished muscle-to-VB area ratios. RESULTS: Both muscle mass and VB areas were considerably larger in males compared with those in females, and the ratio of these two measures was not enough to account for large differences. Thus, a gender-based comparison was made between spine patients and healthy control patients to establish T-scores that would help identify those patients with sarcopenia. The ratio for paravertebral muscle area-to-VB area at the L4 level was the only measure with good interobserver reliability, whereas the other three of the four ratios were moderate. All measurements had excellent correlations for intraobserver reliability. CONCLUSIONS: We postulate that a patient with a T-score <-1 for total paravertebral muscle area-to-VB area ratio at the L4 level is the most reliable method of all our measurements that can be used to diagnose a patient undergoing lumbar spine surgery with sarcopenia.