According to a novel approach highlighted in a study published in Thoracic Cancer, researchers from China have successfully utilised a mixture of tissue adhesive and iohexol to localise small and impalpable pulmonary lesions and nodules under CT guidance.

As per the authors of this study, this method can be safely implemented.

The authors wrote:

“Small pulmonary nodule detection during video-assisted thoracoscopic surgery (VATS) or thoracotomy is frequently challenging; however, accurate and efficient localisation of nodules is critical for precise resection. We introduce and evaluate the feasibility and safety of a novel technique for preoperative pulmonary nodule localisation.”

The study

The researchers identified 140 patients, with a total of 153 pulmonary nodules measuring less than 2 cm in diameter, for the study. They injected the mixture of tissue adhesive and iohexol to localise each nodule via preoperative CT guidance. They assessed patient/nodule characteristics, surgical data, localisation data, complications, and pathological results.

In total, 6.4% of patients underwent two simultaneous nodule localisations and 1.4% underwent three simultaneous nodule localisations. Major complications included pneumothorax in 12.1% of patients, pain in 4.3% of patients, and malodor in 3.6% of patients. Notably, neither embolism nor allergic reactions occurred.

The wide dissemination of low-dose CT to screen for lung cancer has resulted in an explosion in the detection of indeterminate, small pulmonary nodules (SPNs). Although CT can provide detailed features of the lesions, patients are often referred to a thoracic surgeon for surgical resection.

VATS and  SPNs

VATS is considered the gold standard to diagnose and treat pulmonary SPNs, according to the authors. Unlike open-thoracotomy procedures, the minimally invasive nature of VATS is advantageous in decreasing postoperative pain and recovery time, as well as enhancing aesthetics.

Findings

According to the authors:

“It is still challenging for surgeons to identify nodules by palpation or inspection during thoracotomy, especially when nodules are too small or lack sufficient consistency eg, ground-glass opacities (GGOs). Using VATS for SPNs may also be challenging if the nodule is not easily accessible, or if it is located a certain distance from the pleural surface.”

Findings from previous research have indicated that lesions with nodule sizes <10–15 mm, and with a nodule-to-pleura distance of >10 mm, were undetectable on VATS. Ultimately, palpation of pulmonary nodules via a VATS access incision is challenging, particularly when the nodule is small and deep within the lung parenchyma, thus requiring preoperative localisation.

Lesions

Hook-wire placement, micro-coils, and methylene blue injection have all been used in clinical practice to mark lesions preoperatively. These techniques require the percutaneous placement of localising material (eg, hook-wire) or the injection of marking substances (eg, methylene blue).

Although these approaches are satisfactory, they pose the risk of migration or spillage of the material utilised between the radiological intervention and surgery, ideally conducted rapidly and in sequence. Moreover, percutaneous nodule marking can lead to complications akin to image-guided lung biopsies, such as pneumothorax and bleeding, as well as air embolism. 

Conclusion

The current technique of using an injected mixture of tissue adhesive and iohexol as a localisation marker demonstrated certain advantages, according to the authors.

1. First, the adhesive is composed of monomeric n-butyl-2-cyanoacrylate, which polymerises quickly when in contact with tissue fluid, thus forming a tough artificial nodule that is easily identified by inspection or palpation.
2. Second, the adhesive is nontoxic.

Further, the tissue adhesive solidifies rapidly when in contact with tissue fluid, thus decreasing the risk of pneumothorax and embolism. Third, the iodine-contrast medium iohexol permits artificial nodules to be better visualised on CT and accentuates spatial relationships between the artificial and pulmonary nodule, thus allowing surgeons to optimise resection range during surgery. “Our study demonstrates that this novel method is safe and straightforward to implement,” the authors concluded.

This story is contributed by Naveed Saleh and is a part of our Global Content Initiative, where we feature selected stories from our Global network which we believe would be most useful and informative to our doctor members.