Ultrasound Localization in Thoracic Surgery - is Radiation Reduction Achievable?

Background & Rationale

Preoperative localization using spinal needles and fluoroscopy is the conventional method of performing the level check prior to the start of the surgery, with variations including the insertion of radio-opaque markers utilized in some units. Spinal needles are placed either over the skin or inserted directly into the body prior to taking an xray to confirm that the correct spinal levels are identified. The appropriate levels are marked on the skin and the incision is subsequently planned. All techniques currently used employ ionizing radiation, at potentially high doses. In the investigator's experience, they find that due to the various factors which include the type of operating table or frame, the body habitus of the patient (in particular, greater degrees of thoracic kyphosis, and obesity), the inadequacy of the xray images to cover the entire rib cage and the presence of arms tucked to the side often make the localization process tedious and often leaves us with a certain degree of uncertainty.

Ultrasound has been used by various specialties, most notably by anaesthetists and pain specialties to perform point of care interventions to thoracic vertebrae. Ultrasound has also been used in the thoracic region to diagnose rib fractures. Counting the rib levels to localize the appropriate thoracic vertebral level was devised as a progression on these methods.

By showing that the use of ultrasound to count the ribs is a quick and accurate way to localize the appropriate spinal level, the need to expose patients to repeated doses of radiation can be eliminated.

The investigators hypothesize that the use of ultrasound will allow us to accurately determine the appropriate spinal level prior to the start of surgery by counting the ribs. This method will not only be precise, but it will also be quick, non-invasive, cheaper and will limit the amount of radiation that the patient is exposed to.