Correspondence

Abstract

CorrespondenceWe read with interest the report by Shields et al. on the management of cerebrospinal fluid (CSF) leak after accidental dural puncture, as we have recently managed a similar case [1]. An epidural was inserted at L3-4 for labour analgesia in a 32-year-old parturient, however, this was ineffective. A second epidural attempt at the same level 10 h later was complicated by accidental dural puncture. A catheter was threaded 4 cm intrathecally and used for labour analgesia for 6 h until delivery. Over the following 24 h, the patient developed a significant postural headache and leakage of CSF from the site of the epidural attempts.With consent, an epidural blood patch was performed under sterile aseptic conditions and 20 ml of autologous blood was injected into the epidural space at L3-4 with the patient in the left lateral position. The headache resolved within 4 h and no further fluid leakage occurred. The patient was discharged home with no ongoing symptoms.There is no consensus regarding the optimal management of such cases. On reviewing the literature, we felt an epidural blood patch was preferable for our symptomatic patient, noting a case where this was used effectively to manage a persistent CSF leak following spinal catheter insertion during transphenoidal pituitary surgery [2]. Neurosurgical review has also highlighted that epidural blood patch can be beneficial in managing CSF leak following spinal surgery, particularly when the location of the leak is unknown [3].This complication may be more common than previously thought. Such cases provoke thought regarding the use of intrathecal catheters in the management of accidental dural puncture as the development of a CSF leak may be more concerning than a post-dural puncture headache.

Large deflections of inextensible cantilevers: modeling, theory, and simulation

“…Indeed, with ι = 1, no consistent limit cycle oscillation behavior could be observed through the linear pistontheoretic RHS. This is consistent with engineering literature [39,41]. Again, outcomes are highly dependent on initial configuration.…”

“…The first set of numerical tests to be run involve the impact of strong damping k 2 > 0 on controlling the "bad" behaviors of [NL Inertia]. Beyond the effect of damping (perhaps to permit limit cycles), we will attempt to simulate limit cycles by involving the more sophisticated nonlinear piston theory; recent work [39,41] has indicated that large deflection piston theory produces such limit cycle oscillations. Future work will also tackle the problem of determining U crit with nonlinear effects active; specifically, how the linear U crit ≈ 135.9 would lower when σ = 1 and/or ι = 1.…”

Large Deflections of Inextensible Cantilevers: Modeling, Theory, and Simulation

“…Indeed, with ι = 1, no consistent limit cycle oscillation behavior could be observed through the linear piston-theoretic RHS. This is consistent with engineering literature [37,39]. Again, outcomes are highly dependent on initial configuration.…”

“…The first set of numerical tests to be run involve the impact of strong damping k 2 > 0 on controlling the "bad" behaviors of [NL Inertia]. Beyond the effect of damping (perhaps to permit limit cycles), we will attempt to simulate limit cycles by involving the more sophisticated nonlinear piston theory; recent work [37] has indicated that large deflection piston theory produces such limit cycle oscillations. Future work will also tackle the problem of determining U crit with nonlinear effects active; specifically, how the linear U crit ≈ 135.9 would lower when σ = 1 and/or ι = 1.…”