Spinal fractures in fused spines: nonoperative treatment is a reliable alternative

INTRODUCTION

Spinal fractures in fused spines such as in ankylosing spondylitis or DISH are typically of type B or C fractures where operative treatment is recommended. The mortality rate in non-operatively treated patients is reported to be 51%. The purpose of this study was to investigate the mortality rate, complication rate and demographics of patients following non-operatively treatment in fused spine injuries.

METHODS

Between 2019 and 2021, a retrospective study was conducted including all patients who presented to our trauma center with a spinal fracture of a fused spine. Radiology and patient charts were analyzed for fracture pattern, complications, neurological deficit, comorbidities, and mortality rate.

RESULTS

A total of 49 patients were found at a mean age was 79.8 ± 10.9 years and primarily males were affected in 65.3%. All fractures were of type B and the thoracic spine was involved in 85.7%. The mean follow-up was 6.3 ± 8.2 months and fusion was obtained in all patients. No neurological deficit was observed in any. A total of 13 patients died at a mean age of 86.5 ± 10.0 years after 157.1 ± 158.1 days. 6 patients (10.2%) deceased within the first 6 weeks at a mean age of 91.8 ± 3.8 years. One patient each suffered from heart failure, an acute delirium, end stage colon cancer and subdural hemorrhage.

CONCLUSION

This study shows that the mortality rate in the first 6 weeks following a fracture in a fused spine is 10.2% for patients above the age of 90 years. Therefore, non-operative treatment should be taken into consideration as the mortality rate in other studies may be overestimated.

LEVEL OF EVIDENCE

III, retrospective study.

Bilateral, fused pelvic, ectopic, laterally rotated kidneys: A case report

Bilateral fused ectopic pelvic kidneys with lateral rotation abnormality in both kidneys is a fortuitous developmental renal anomaly that to the best of our knowledge this is the first report of this rare anomaly in English literature. Due to the morphologic appearance of this anomaly it is likely it could contribute to the individual remaining asymptomatic therefore discovered incidentally. We present a 42-year-old male who presented with acute unilateral flank pain and incidentally discovered this rare renal anomaly which is an important diagnosis for management by both radiologists and urologists.

Femoral non-union above a fused knee: Successful treatment with exchange nailing and intramedullary delivery of bone morphogenetic protein

Bone healing is a complex and well-orchestrated physiological process, in which bone repairs and regenerates regaining its original biomechanical and biochemical properties. It is estimated that 5 to 10% of all fractures are complicated by delayed union or non-union. Progression to non-union is thought to be multifactorial, even though the exact biological sequence remains obscure. Treatment should aim to addressing deficiencies in both the mechanical and biological components, along with eliminating co-factors that could negatively affect the locally induced fracture healing response. We report a case of a 78-year-old patient who presented with a distal femoral non-union above a previously fused knee, which was successfully managed with exchange nailing and intramedullary delivery of recombinant human bone morphogenetic protein-7 (rhBMP-7).

Protein association changes in the Hedgehog signaling complex mediate differential signaling strength

Hedgehog (Hh) is a conserved morphogen that controls cell differentiation and tissue patterning in metazoans. In Drosophila, the Hh signal is transduced from the G protein-coupled receptor Smoothened (Smo) to the cytoplasmic Hh signaling complex (HSC). How activated Smo is translated into a graded activation of the downstream pathway is still not well understood. In this study, we show that the last amino acids of the cytoplasmic tail of Smo, in combination with G protein-coupled receptor kinase 2 (Gprk2), bind to the regulatory domain of Fused (Fu) and highly activate its kinase activity. We further show that this binding induces changes in the association of Fu protein with the HSC and increases the proximity of the Fu catalytic domain to its substrate, the Costal2 kinesin. We propose a new model in which, depending on the magnitude of Hh signaling, Smo and Gprk2 modulate protein association and conformational changes in the HSC, which are responsible for the differential activation of the pathway.

Drosophila Segment Polarity Mutants and the Rediscovery of the Hedgehog Pathway Genes

The Nüsslein-Volhard and Wieschaus screen for mutations disrupting the segmentation of the Drosophila embryo revolutionized developmental genetics, leading the way to the identification of many of the transcription factors and signaling pathways that orchestrate development, not just in the fruit fly but across the animal kingdom. The Hedgehog signaling pathway is a case in point: yet remarkably, all but one of the genes encoding the Hedgehog pathway components-including Hedgehog itself-had previously been discovered, in some cases decades earlier. Here I review the original identification of these genes and consider why their significance remained obscure until the Nobel Prize winning screen.

Contributions of Costal 2-Fused interactions to Hedgehog signaling in Drosophila

The Drosophila kinesin-family protein Costal 2 (Cos2) and its mammalian ortholog Kif7 play dual roles in Hedgehog (Hh) signaling. In the absence of Hh, Cos2 and Kif7 contribute to proteolytic processing and silencing of the Hh-regulated transcription factors, Drosophila Cubitus interruptus (Ci) and mammalian Gli proteins. Cos2 and Kif7 are also necessary for full activation of full-length Ci-155 and Gli transcription factors in response to Hh proteins. Here, we use classical fused alleles and transgenic Cos2 products deficient for Fused (Fu) association to show that Cos2 must bind to Fu to support efficient Ci-155 processing. Residual Ci-155 processing in the absence of Cos2-Fu interaction did not require Suppressor of Fused, which has been implicated in processing mammalian Gli proteins. We also provide evidence that Cos2 binding to the CORD domain of Ci-155 contributes to both Ci-155 processing and Ci-155 silencing in the absence of Hh. In the presence of Hh, Ci-155 processing is blocked and Cos2 now promotes activation of Ci-155, which requires Fu kinase activity. Here, we show that normal Ci-155 activation by Hh requires Cos2 binding to Fu, supporting the hypothesis that Cos2 mediates the apposition of Fu molecules suitable for cross-phosphorylation and consequent full activation of Fu kinase. We also find that phosphorylation of Cos2 by Fu at two previously mapped sites, S572 and S931, which is thought to mediate Ci-155 activation, is not required for normal activation of Ci-155 by Hh or by activated Fu.

Mammalian Fused is essential for sperm head shaping and periaxonemal structure formation during spermatogenesis

During mammalian spermatogenesis, the diploid spermatogonia mature into haploid spermatozoa through a highly controlled process of mitosis, meiosis and post-meiotic morphological remodeling (spermiogenesis). Despite important progress made in this area, the molecular mechanisms underpinning this transformation are poorly understood. Our analysis of the expression and function of the putative serine-threonine kinase Fused (Fu) provides critical insight into key steps in spermatogenesis. In this report, we demonstrate that conditional inactivation of Fu in male germ cells results in infertility due to diminished sperm count, abnormal head shaping, decapitation and motility defects of the sperm. Interestingly, mutant flagellar axonemes are intact but exhibit altered periaxonemal structures that affect motility. These data suggest that Fu plays a central role in shaping the sperm head and controlling the organization of the periaxonemal structures in the flagellum. We show that Fu localizes to multiple tubulin-containing or microtubule-organizing structures, including the manchette and the acrosome-acroplaxome complex that are involved in spermatid head shaping. In addition, Fu interacts with the outer dense fiber protein Odf1, a major component of the periaxonemal structures in the sperm flagellum, and Kif27, which is detected in the manchette. We propose that disrupted Fu function in these structures underlies the head and flagellar defects in Fu-deficient sperm. Since a majority of human male infertility syndromes stem from reduced sperm motility and structural defects, uncovering Fu׳s role in spermiogenesis provides new insight into the causes of sterility and the biology of reproduction.