Compressive Osseointegration of Tibial Implants in Primary Cancer Reconstruction

Compressive osseointegration technology, which provides immediate, mechanically compliant endoprosthetic fixation, has been adapted for massive proximal tibial reconstructions in an attempt to avoid aseptic failure encountered with conventional stems. A retrospective review of 16 patients with resected tumors was undertaken to determine whether compressive osseointegration can provide durable anchorage of tibial implants. Medical records, radiographs, and clinical examinations were reviewed to assess surgical, local disease control, and prosthetic outcomes. The average age was 18 years (range, 12–42 years). Diagnoses included osteosarcoma (12), Ewing sarcoma (two), chondrosarcoma (one), and undifferentiated sarcoma (one). Minimum followup was 2 years (mean, 4.5 years; range, 2–10.3 years); no patient was lost to followup. There were no local recurrences. Four patients developed metastatic disease; one patient died of his primary tumor, and another died from a chemotherapy-related malignancy. Complications included one early deep infection that ultimately resulted in prosthetic loosening and the need for an above-knee amputation. There were two late deep infections; prosthetic retention was achieved with débridement and antibiotics. One patient developed aseptic loosening and underwent revision; the other 15 implants provided stable osseointegration at last followup. Compressive osseointegration technology can thus achieve acceptable short-term endoprosthetic fixation results and may reduce the risk of aseptic loosening reported with conventional tibial stems

Student-Produced Guides alongside First-Year Medical Curriculum: How Peer-Produced Textbooks Change Student Success within Neurology, Cardiopulmonary, and Mixed Systems Courses.

OBJECTIVES: In the United States, medical schools do not have a unified curricular plan that integrates basic sciences and organ-based systems in undergraduate medical education. Instead, institutions rely on independently created lecture material during the first-year medical school curriculum. The drawback to this approach is that no commercial or organizational resources cater to this individualized study plan. This study explored whether students who use student-produced course guides experience increased first-year success and improved skills. METHODS: First-year students at an allopathic medical school completed anonymous surveys about their reference guide usage, time management, organization, stress level, and examination scores. Statistical analysis was performed using Spearman\u27s coefficient of correlation and χ RESULTS: In total, 186 total students received the survey three times immediately after completing each organ system-based course. A total of n = 49 viable responses were received. One-fourth of the respondents used the guides for ≥3 hours/week. Respondents who used the reference guides reported improved time management, organization, self-confidence, and reduced student stress levels during the first year of medical school, but examination scores were unaffected. CONCLUSIONS: Access to student-produced guides increased confidence in self-rated measures of time management skills, organizational ability, and ability to balance medical course expectations. Because of the small sample size, future work will expand the survey population to increase the power to detect differences in these factors

The Fundamentals of Illustration, 3rd Edition

An introduction to Illustration practice included key samples demonstrating a variety of approaches by key international practitioners

Incidental Metaplastic Primary Pulmonary Meningioma.

Primary pulmonary meningioma is a rare benign tumor usually presenting as a solitary pulmonary nodule or mass. It can be easily misinterpreted as a primary lung tumor or metastases on imaging studies. We present a 54-year-old woman with an incidentally discovered solitary lung nodule, which was diagnosed as metaplastic primary pulmonary meningioma following resection. Metaplastic meningioma is a rare WHO grade 1 meningioma subtype with focal or global mesenchymal differentiation. To the authors\u27 knowledge, primary pulmonary meningioma with mesenchymal differentiation has not been described previously in the English literature

Clival-Meckel\u27s Cave Angle: A Predictor of Glycerol Displacement in Percutaneous Glycerol Rhizotomy for Trigeminal Neuralgia.

BACKGROUND AND OBJECTIVES: Percutaneous glycerol rhizotomy successfully treats trigeminal neuralgia although failure rates and durability of the procedure are variable. Some of this variability in clinical outcome might be due to egress of glycerol from Meckel\u27s cave (MC) because of surgical positioning and individual patient anatomy. In this article, we quantitatively analyzed the anatomic variances that affect glycerol fluid dynamics to better predict patients more amenable for percutaneous glycerol injections. METHODS: Computed tomography imaging of 11 cadaveric heads was used to calculate bilateral Clival-Meckel\u27s cave (CMC) and sella-temporal (ST) angles. Twenty-two cadaveric percutaneous injections of dyed glycerol into the Meckel\u27s cave were performed using Härtel\u27s approach, and the fluid movement was documented at prespecified intervals over 1 hour. The relationship between the angles and glycerol migration was studied. RESULTS: Specimens with basal cistern involvement by 60 minutes had significantly greater CMC angles (median [IQR]: basal cistern involvement = 74.5° [59.5°-89.5°] vs no basal cistern involvement = 58.0° [49.0°-67.0°]), U = 6.0, P \u3c .001. This model may predict which patients will experience glycerol migration away from the Gasserian ganglion (area under the curve: 0.950, SE: 0.046, CI: 0.859-1.041, P \u3c .001). Increased ST angle was associated with lateral flow of glycerol (rs = 0.639, P = .001), and CMC angle was associated with total area of dispersion (rs = -0.474, P = .026). CONCLUSION: Anatomic variation in skull base angles affects glycerol migration. Specifically, a more obtuse CMC angle was associated with a higher risk of posterior migration away from the Gasserian ganglion. This may be a reason for differing rates of surgical success. These results suggest that anterior head flexion for 60 minutes may prevent percutaneous glycerol rhizotomy failures and some patients with large CMC angles are more likely to benefit from postinjection head positioning. However, this clinical effect needs validation in vivo

Evaluation of rhBMP-2 with an OPLA carrier in a canine posterolateral (transverse process) spinal fusion model.

Study designPosterolateral L4-L5 transverse process fusions were done on 14 adult beagles. Six were implanted with recombinant human bone morphogenetic protein-2 carried by open-cell polylactic acid polymer delivery vehicle. Six received autogenous iliac bone graft. Two received carrier alone. Eleven were killed 3 months after implantation. One in each group was maintained for 8 months.ObjectivesTo compare recombinant human bone morphogenetic protein-2 and open-cell polylactic acid polymer with autogenous iliac bone for inducing transverse process fusion in the canine by 3 months and to determine whether transverse process decortication and implantation of carrier alone causes spontaneous transverse process fusion in the canine.Summary of background dataRecombinant human bone morphogenetic proteins have healed segmental long bone defects in several models. They have induced interlaminar and facet fusions in canines. Interlaminar and facet fusions have occurred after sham decortications in canines. Recombinant human bone morphogenetic protein-2 has not been evaluated for transverse process fusion in canines. Transverse process fusion is a preferred clinical method for achieving posterior lumbar fusion.MethodsFusion sites were evaluated by serial computed tomography scans. After the dogs were killed, explanted spines were subjected to manual testing, mechanical testing, high resolution radiography, and histologic analysis.ResultsOne hundred percent of recombinant human bone morphogenetic protein-2-implanted sites had solid transverse process fusion by 3 months according to all measures. No autografted sites were fused at this interval. Osseous bridging of posterolateral gutters occurred in the recombinant human bone morphogenetic protein-2-implanted sites after 2 months, the earliest radiographic measure. None of the carrier-only sites showed bone formation.ConclusionsRecombinant bone morphogenetic protein-2 carried by open-cell polyactic acid polymer is superior to autogenous iliac bone for producing radiographically and mechanically solid transverse process fusions in canines by 3 months. Spontaneous transverse process fusion does not occur in canines after decortication and open-cell polylactic acid polymer implantation

Evaluation of rhBMP-2 with an OPLA carrier in a canine posterolateral (transverse process) spinal fusion model.

Study designPosterolateral L4-L5 transverse process fusions were done on 14 adult beagles. Six were implanted with recombinant human bone morphogenetic protein-2 carried by open-cell polylactic acid polymer delivery vehicle. Six received autogenous iliac bone graft. Two received carrier alone. Eleven were killed 3 months after implantation. One in each group was maintained for 8 months.ObjectivesTo compare recombinant human bone morphogenetic protein-2 and open-cell polylactic acid polymer with autogenous iliac bone for inducing transverse process fusion in the canine by 3 months and to determine whether transverse process decortication and implantation of carrier alone causes spontaneous transverse process fusion in the canine.Summary of background dataRecombinant human bone morphogenetic proteins have healed segmental long bone defects in several models. They have induced interlaminar and facet fusions in canines. Interlaminar and facet fusions have occurred after sham decortications in canines. Recombinant human bone morphogenetic protein-2 has not been evaluated for transverse process fusion in canines. Transverse process fusion is a preferred clinical method for achieving posterior lumbar fusion.MethodsFusion sites were evaluated by serial computed tomography scans. After the dogs were killed, explanted spines were subjected to manual testing, mechanical testing, high resolution radiography, and histologic analysis.ResultsOne hundred percent of recombinant human bone morphogenetic protein-2-implanted sites had solid transverse process fusion by 3 months according to all measures. No autografted sites were fused at this interval. Osseous bridging of posterolateral gutters occurred in the recombinant human bone morphogenetic protein-2-implanted sites after 2 months, the earliest radiographic measure. None of the carrier-only sites showed bone formation.ConclusionsRecombinant bone morphogenetic protein-2 carried by open-cell polyactic acid polymer is superior to autogenous iliac bone for producing radiographically and mechanically solid transverse process fusions in canines by 3 months. Spontaneous transverse process fusion does not occur in canines after decortication and open-cell polylactic acid polymer implantation

Transorbital Surgical Corridor: An Anatomic Analysis of Ocular Globe Retraction and the Associated Exposure for the Transpalpebral Orbital Rim Preserving Endoscopic Orbitotomy (TORPEDO) Approach.

BACKGROUND AND OBJECTIVES: The transorbital approach varies by the extent of bony removal and the target. Orbital rim-sparing transorbital approach with removal of only the orbit\u27s posterior wall provides optimal cosmetic results, without the need for reconstruction. The size of this corridor, limited by the medial globe retraction, has not yet been defined and is difficult to determine in cadavers because of postmortem tissue desiccation. By using patient-specific models in virtual reality, precise areas and degrees of surgical freedom (AOF and DOF, respectively) provided by globe retraction were calculated. These measurements define a potential maximum safe AOF and DOF, as well as the globe retraction, needed to achieve a sufficient surgical corridor. METHODS: Using a virtual reality system, transorbital rim-preserving craniectomies were performed. The axial and sagittal DOF as well as AOF were calculated lateral to the globe, limited by the orbital rim and globe, with an anterior clinoid target. The DOFs and AOFs were calculated for each degree of medial globe retraction and analyzed using paired t tests. RESULTS: With only 5 mm of retraction, the AOF was 886 mm2, while at 10 mm, the AOF was 1546 mm2. This increase between 5 and 10 mm allowed for the largest increase in surgical working corridor (P = .02). At 15 mm of retraction (previously studied point at which intraocular pressure raises), the AOF averaged 2189 mm2 and axial DOF averaged 23.1°. Eighteen DOF (a previously studied point needed to achieve sufficient working space for 2 instruments) was achieved at 11 mm on average, generating 1675 mm2 AOF. CONCLUSION: Globe retraction of 11 mm is needed to achieve sufficient DOF for 2 surgical instruments, and 15 mm of retraction is a conservative limit that provides comparable AOFs with similar cranial approaches