ABSTRACT
The paleohistology of dyrosaurids is known from a small sample, despite being common fossils and representing a rare lineage of crocodylomorphs that survived the Cretaceous-Paleogene extinction. Their lifestyle has been inferred only from sections of the snout, vertebrae, partial femur, and tibia. To improve this, we conducted a skeletochronological and paleohistological study of midshaft cross-sections of both femora and humeri of a nearly complete Hyposaurus rogersii skeleton. We found lamellar-zonal bone that underwent remodeling, evidenced by resorption cavities and abundant secondary osteons within the primary periosteal cortex. The osteons, mostly longitudinally oriented and arranged in circular rows, often anastomose radially along a linear path, resembling radial rows. The medullary cavity is completely open, lacking trabeculae: endosteal deposition is limited to thin lamellae surrounding the cavity. Analysis of cyclical growth marks and the presence of an external fundamental system indicate the specimen was a fully mature adult 17-18 years of age. Comparison of the skeleton to others suggests sexual dimorphism and that it was female. The open medullary cavity, and no evidence for pachyosteosclerosis, osteosclerosis, osteoporosis, or pachyostosis indicate H. rogersii was not a deep diver or a fast swimmer in the open ocean but a near-shore marine ambush predator.
Subject(s)
Allergens/immunology , Anaphylaxis/diagnosis , Anti-Infective Agents, Local/immunology , Chlorhexidine/immunology , Drug Hypersensitivity/diagnosis , Administration, Topical , Adult , Anti-Infective Agents, Local/therapeutic use , Chlorhexidine/therapeutic use , Drug Administration Routes , Drug Dosage Calculations , Female , Humans , Immune Tolerance , Male , Middle AgedABSTRACT
BACKGROUND: Inguinal hernia repair is associated with a high incidence of chronic postsurgical pain. This pain may be caused by injury to the iliohypogastric, ilioinguinal, or genitofemoral nerves. It is often difficult to identify the specific source of the pain, in part, because these nerves are derived from overlapping nerve roots and closely colocalize in the area of surgery. It is therefore technically difficult to selectively block these nerves individually proximal to the site of surgical injury. In particular, the genitofemoral nerve is retroperitoneal before entering the inguinal canal, a position that puts anterior approaches to the proximal nerve at risk of transgressing into the peritoneum. We report a computed tomography (CT)-guided transpsoas technique to selectively block the genitofemoral nerve for both diagnostic and therapeutic purposes while avoiding injury to the nearby ureter and intestines. CASE: A 39-year-old woman with chronic lancinating right groin pain after inguinal hernia repair underwent multiple pharmacologic interventions and invasive procedures without relief. Using CT and Stimuplex nerve stimulator guidance, the genitofemoral nerve was localized on the anterior surface of the psoas muscle and a diagnostic block with local anesthetic block was performed. The patient had immediate relief of her symptoms for 36 hours, confirming the diagnosis of genitofemoral neuralgia. She subsequently underwent CT-guided radiofrequency and phenol ablation of the genitofemoral nerve but has not achieved long-term analgesia. CONCLUSION: CT-guided transpsoas genitofemoral nerve block is a viable option for safely and selectively blocking the genitofemoral nerve for diagnostic or therapeutic purposes proximal to injury caused by inguinal surgery.
