Intraneural (subepineural) injection is a common occurrence after nerve stimulator-guided SN block at the popliteal fossa, yet it may not inevitably lead to neurological complications.

Main problem: Little is known about the methodological quality of guidelines for low back pain treatment. We evaluated the methods used by the developers according to established standards. Methods: PubMed, guideline databases, and the World Wide Web were used to identify guidelines. Seventeen guidelines met the inclusion criteria: interventions for low back pain stated, recommendations based on or explicitly linked to evidence, and English version available. Guidelines were evaluated independently by two appraisers using a practical tool for this purpose, Users' Guides to the Medical Literature, and the Appraisal of Guidelines for Research and Evaluation (AGREE) instrument. Results: Thirteen guidelines (76%) specified the most important therapies applied, but only nine (53%) included a complete description of the target population. Explicit processes to identify, select, and combine evidence were described in only six guidelines (35%). Few guidelines (3; 18%) explicitly considered all main outcomes when formulating therapeutic recommendations, and none contained a process to determine the relative value of different outcomes. Methodological criteria for grading the strength of the recommendations varied, and were often insufficiently specified. None of the guidelines assessed the impact of uncertainty associated with the evidence and values used. According to AGREE the quality score was highest for the scope and purpose, and clarity and presentation domains, and lowest for editorial independence and applicability. With regard to the recommendations, there was consensus for some of the interventions for acute pain (analgesics and NSAIDs, maintaining physical activity, and avoiding excessive bed rest), but explicit recommendations were lacking or ambiguous for 41% of the interventions. Most of the guidelines did not contemplate specific recommendations for chronic pain. Conclusions: A small number of the available guidelines for low back pain treatment achieved acceptable results for specific quality criteria. In general, the methods to develop the guidelines' therapeutic recommendations need to be more rigorous, more explicit and better explained. In addition, greater importance should be placed on the recommendations for chronic pain.

Airway management in patients anaesthetized in the prone position was efficient with both devices, although the PLMA required fewer manipulations and achieved a higher seal pressure.