Wandering paravertebral catheter detected during thoracoscopy.

We report a case of intrapleural migration of paravertebral catheter inserted under ultrasound guidance, detected during video assisted thoracoscopic surgery.

History

A 45-year-old man with a diagnosis of squamous cell carcinoma lung was planned for right upper lobectomy. After standard anesthesia induction, the airway was secured with a left-sided double lumen endotracheal tube. The right radial artery and internal jugular vein were cannulated uneventfully. The patient was then placed in the left lateral position and the right sixth thoracic paravertebral space was identified using ultrasound with the probe placed longitudinally. An 18-G tuohy needle was advanced out of plane into the space under sonographic guidance in the third attempt. A saline flush through the tuohy needle showed satisfactory anterior displacement of the pleura. Following this, a 20-G epidural catheter was threaded into the paravertebral space. One-lung ventilation was subsequently commenced. However, on introduction of the thoracoscopic port, the epidural catheter could be visualized projecting from the thoracic wall and extending up to the deflated lung [Figure 1]. The catheter was carefully withdrawn under thoracoscopic visualization until the blue tip of the catheter just disappeared from the view. Surgery proceeded uneventfully.

Figure 1

Misplaced paravertebral catheter in thoracic cavity. Lungs are deflated. Image of tubelight also seen

An infusion of local anesthetic through the repositioned catheter provided good postoperative pain relief.

Discussion

The advent of ultrasound has popularized and increased the safety of the paravertebral block for unilateral thoracic and upper abdominal procedures.[1] Many different ultrasound probe placements have been described, but there are no studies comparing and proving the superiority of any one approach.[2] The choice ultimately rests on the preference and experience of the operator. The risk of pleural puncture, though lower under sonographic guidance, is still 0.8%–1.1%.[3] We opted for the out of plane approach where it is difficult to visualize the needle tip. Our repeated attempts may have created a false passage into the pleura through which the catheter may have migrated into the intrapleural space while threading. Because the catheter was inserted preoperatively, we could detect the complication during surgery and reposition the catheter under vision.

In the ultrasound-guided method, the correct position of the needle can be confirmed by observing the anterior displacement of the pleura when saline is flushed through the needle.[4] However, the pleura is not a well-defined continuous boundary of the paravertebral space if the parietal pleura over the paravertebral space medial to the angle of the rib is breached during surgical dissection.[5] This endpoint is, thus, less reliable postoperatively. Moreover, the catheter is always advanced blindly through the needle. It is not possible to flush the catheter with any force; hence, the anterior pleural displacement cannot be appreciated here. Therefore, it is challenging to position the catheter even with ultrasound guidance, especially postoperatively.

In our case, we turned around a potential complication into a simple method to locate the catheter in the correct space. Video-assisted placement of a paravertebral catheter under direct vision during thoracoscopic surgery has been described by Soni et al.[5]

We suggest that in thoracic surgeries, it is advisable to place the paravertebral catheter before surgery because of two reasons – presence of an intact pleura makes it easier to confirm the position of the needle sonographically, and also, any intrapleural misplacement of the catheter may be detected and corrected under vision during surgery.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.