Background This report is a summary of a review conducted by the Health Quality Council of Alberta (HQCA) in response to a request by the College of Physical Therapists of Alberta (College) to complete an independent review of adverse outcomes, specifically pneumothorax, resulting from dry needling practices by physiotherapists in Alberta, in order to improve the quality and safety of this practic [...] Because dry needling is an invasive procedure that penetrates the skin, it is critical that the practitioner has thorough knowledge of surface anatomy, the underlying structures of the thorax including anatomical anomalies, as well as knowledge about the management of adverse events such as pneumothorax. [...] A categorization of a needling technique that refers to the target depth of the needle.1 Defined as the insertion of needles into the subcutaneous tissues immediately overlying a trigger point.3 Deep dry needling. [...] A categorization of needling that refers to insertion of needles into the muscle and into the trigger point to elicit a local twitch response.4 Gunn IMS is an example of deep needling technique. [...] The National Reporting and Learning System attempts to categorize the range of adverse outcomes (i.e., moderate or severe), however there is no denominator indicating the total number of treatments, and thus metrics, such as the rate of adverse outcomes, cannot be determined.