Postpartum Sciatic Neuropathy After Uncomplicated Vaginal Delivery.

Postpartum neuropathies are common, including femoral neuropathy, peroneal neuropathy, lumbosacral trunk plexopathy, and lateral femoral cutaneous neuropathy. Sciatic mononeuropathy in the peripartum period is rare. Postpartum sciatic neuropathy (PSN) in the setting of cesarean section has been reported before. We present a case series of 2 sciatic mononeuropathies after vaginal delivery. Case 1 is a 25-year-old woman who presented with a left foot drop after normal vaginal delivery after being in labor for 3 hours. Case 2 is a 24-year-old woman who presented with a right foot drop after normal vaginal delivery and being in labor for 31 hours. Both cases noted foot drops in the immediate postpartum period. Neurologic examinations revealed flail foot, 4/5 hamstring muscle strength on MRC scale and intact hip abduction. They had paresthesia on the posterolateral aspect of the leg, dorsal and plantar aspect of the foot with absent ankle reflex. MRI did not show evidence of spinal cord, nerve root or plexus involvement. Electrodiagnostic studies revealed evidence of sciatic mononeuropathy proximal to the short head of biceps femoris. They were discharged home with an ankle brace and therapy. At 3 months follow up, they had complete resolution of weakness. There have been a few reported cases of PSN secondary to cesarean section. Sciatic involvement after vaginal delivery is extremely rare. We report 2 cases of PSN after vaginal delivery to highlight that sciatic mononeuropathy can occur not only after cesarean section, but also after uncomplicated vaginal delivery and should raise awareness of this risk to clinicians.

A geometric basis for surface habitat complexity and biodiversity.

Structurally complex habitats tend to contain more species and higher total abundances than simple habitats. This ecological paradigm is grounded in first principles: species richness scales with area, and surface area and niche density increase with three-dimensional complexity. Here we present a geometric basis for surface habitats that unifies ecosystems and spatial scales. The theory is framed by fundamental geometric constraints between three structure descriptors-surface height, rugosity and fractal dimension-and explains 98% of surface variation in a structurally complex test system: coral reefs. Then, we show how coral biodiversity metrics (species richness, total abundance and probability of interspecific encounter) vary over the theoretical structure descriptor plane, demonstrating the value of the theory for predicting the consequences of natural and human modifications of surface structure.

Climate-driven shift in coral morphological structure predicts decline of juvenile reef fishes.

Rapid intensification of environmental disturbances has sparked widespread decline and compositional shifts in foundation species in ecosystems worldwide. Now, an emergent challenge is to understand the consequences of shifts and losses in such habitat-forming species for associated communities and ecosystem processes. Recently, consecutive coral bleaching events shifted the morphological makeup of habitat-forming coral assemblages on the Great Barrier Reef (GBR). Considering the disparity of coral morphological growth forms in shelter provision for reef fishes, we investigated how shifts in the morphological structure of coral assemblages affect the abundance of juvenile and adult reef fishes. We used a temporal dataset from shallow reefs in the northern GBR to estimate coral convexity (a fine-scale quantitative morphological trait) and two widely used coral habitat descriptors (coral cover and reef rugosity) for disentangling the effects of coral morphology on reef fish assemblages. Changes in coral convexity, rather than live coral cover or reef rugosity, disproportionately affected juvenile reef fishes when compared to adults, and explained more than 20% of juvenile decline. The magnitude of this effect varied by fish body size with juveniles of small-bodied species showing higher vulnerability to changes in coral morphology. Our findings suggest that continued large-scale shifts in the relative abundance of morphological groups within coral assemblages are likely to affect population replenishment and dynamics of future reef fish communities. The different responses of juvenile and adult fishes according to habitat descriptors indicate that focusing on coarse-scale metrics alone may mask fine-scale ecological responses that are key to understand ecosystem functioning and resilience. Nonetheless, quantifying coral morphological traits may contribute to forecasting the structure of reef fish communities on novel reef ecosystems shaped by climate change.