Background: Pediatric spinal deformity surgeries are challenging operations that require considerable expertise and resources. The unique anatomy and rarity of these cases present challenges in surgical training and preparation. We present a case series illustrating how 3-dimensional (3-D) printed models were used in preoperative planning for 3 cases of pediatric spinal deformity surgery. Case Series: Patient 1 was a 6-year-old male with scoliosis secondary to an L3 hemivertebra and severe congenital heart disease who underwent excision of the L3 hemivertebra and L2-L4 spinal fusion. Patient 2 was an 11-year-old male with an L2 hemivertebra and lumbar kyphosis who underwent excision of the L2 hemivertebra and T12-L4 spinal fusion. Patient 3 was a 6-year-old female with Down syndrome who presented with atlantoaxial instability and acute lymphoblastic leukemia. She underwent occipitalcervical spinal fusion and decompression. Prior to surgery, 3-D printed models of the patients' spines were created based on computed tomography (CT) imaging. Conclusion: The anatomic complexity and risk of devastating neurologic consequences in spine surgery call for careful preparations. 3-D models enable more efficient and precise surgical planning compared to the use of 2-dimensional CT/magnetic resonance images. The 3-D models also make it easier to visualize patient anatomy, allowing patients and their families who lack medical training to interpret and understand cross-sectional anatomy, which in our experience, enhanced the consultations.

Nerve guidance conduits (NGCs) have emerged from recent advances within tissue engineering as a promising alternative to autografts for peripheral nerve repair. NGCs are tubular structures with engineered biomaterials, which guide axonal regeneration from the injured proximal nerve to the distal stump. NGC design can synergistically combine multiple properties to enhance proliferation of stem and neuronal cells, improve nerve migration, attenuate inflammation and reduce scar tissue formation. The aim of most laboratories fabricating NGCs is the development of an automated process that incorporates patient-specific features and complex tissue blueprints (e.g. neurovascular conduit) that serve as the basis for more complicated muscular and skin grafts. One of the major limitations for tissue engineering is lack of guidance for generating tissue blueprints and the absence of streamlined manufacturing processes. With the rapid expansion of machine intelligence, high dimensional image analysis, and computational scaffold design, optimized tissue templates for 3D bioprinting (3DBP) are feasible. In this review, we examine the translational challenges to peripheral nerve regeneration and where machine intelligence can innovate bottlenecks in neural tissue engineering.

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The aim of this study is to elucidate in which subset of patients chemotherapy offers a real benefit. Methods: We retrospectively investigated the US National Cancer Data Base and evaluated patients who underwent pancreatic resection (pancreaticoduodenectomy, partial and distal pancreatic resection) for PNET from 2004 to 2014. Differences between two groups, Chemotherapy Group (CH), and Surgery Alone Group (S) were analyzed, and comparison was performed to identify the beneficial effect of chemotherapy. Study end point was overall survival. Results: Population study included 13822 patients, 8259 were in Group CH and 5563 were in Group S The two groups were well matched in demographic profile including age, race distribution, co-morbidities (Charlson/Deyo Score), pathological stage, grading and status of resection margins. Multivariable Cox proportional hazard regression model demonstrated pathological grade (HR1.680), positive surgical margin (HR 1.403), local invasion (HR 1.645) associated with overall survival, instead lymphovascular invasion (HR 1.030, NS) and positive node (HR 1.175) have a marginal effect on it. Kaplan-Meier analysis demonstrated no superior survival for Chemotherapy group when compared to Surgery alone group despite positive node (mean OS 27.3 months vs 27.8 months, NS),positive surgical margin (mean OS 27.3 months vs 28.5 months, NS), positive lymphovascular invasion (mean OS 28.4 months vs 36.1 months, NS) and local invasion (mean OS 29.0 months vs 29.9 months, NS). Chemotherapy has a limited effect only with poorly/undifferentiated lesion (mean OS 25.5 months vs 17.6 months, p < .005). Conclusion:Current chemotherapy regimen has a beneficial effect limited to high grade lesion. Extensive surgical resection is the only treatment that offers a survival benefit even for cancer that presents with aggressive features including positive margins, local invasion, positive lymphnode and presence of lymphovascular invasion.

Peripheral nerve injuries occur through three mechanisms, specifically, crush, compression or transection. Disruption of communication between the peripheral and central nervous system follows and leads to motor and sensory deficits. Peripheral nerves in humans have a limited capacity to self-regenerate following injury, which makes nerve transfer the current gold-standard for treatment. Functional nerve regeneration is contingent on several factors ranging from span of injury and the age of the patient. Bioprinted nerve guidance conduits are an emerging candidate for treating peripheral nerve injuries. To optimize the performance of nerve guidance conduits, a firm understanding of neurobiology and the pathophysiology following injury is necessary. This article provides an overview of nerve regeneration and the desirable features when designing a nerve conduit from a neurosurgical perspective.