Push–pull monorail technique to overcome a difficult course through the left internal jugular vein

Abstract

Background:

We assessed the outcomes of a push–pull monorail technique to overcome a difficult anatomical course through the left internal jugular vein in implantable port insertions.

Methods:

From December 2018 to May 2021, a total of 5326 patients were referred for implantable port insertion in our interventional unit, among which 472 cases were requested for insertion on the left side. Our monorail technique was applied only when the catheter tip entered the azygos vein instead of the superior vena cava (n = 8). The technique consists of a puncture at the distal tip of the port catheter with a 21-gauge micropuncture needle, advancing a 0.018-inch hair-wire to the guide, providing support for the pre-assembled port, and advancing the microsheath over the hair-wire to prevent extrusion of the catheter.

Results:

The push–pull monorail technique was performed in eight patients, and all cases were technically successful, exhibiting a technical success rate of 100%. There were no immediate or delayed complications.

Conclusions:

The push–pull monorail technique is helpful in overcoming the difficult anatomical course through the left internal jugular vein during implantable port insertion.

Introduction

Clinicians are always searching for better ways to administer therapeutic agents, and for chemotherapy, intensive methods have developed with an increasing demand for implantable devices that allow long-term vascular access. Central intravenous administration has been shown to reduce or eliminate venous toxicity in chemotherapy and implantable ports locked to a central line eliminate the need for external dressing, allow a more active lifestyle, and require only monthly flushes of heparinized saline to maintain catheter patency. Therefore, implantable ports have become essential for improving the quality of life in modern oncology. ¹

The preferred site for central venous access is the right internal jugular vein (IJV) because it provides a direct path to the superior vena cava (SVC). ² However, another entrance route is necessary for certain situations such as occlusion due to repeated access, injury from past surgery or trauma, radiation, and infection, or in consideration of a future right mastectomy. ³

In these situations, the left IJV is chosen, although it is less accessible compared to the right IJV because the path a left-sided catheter must traverse when making its way to the right atrium has more angulations.^2,4 In addition, a left-sided catheter can easily enter the azygos vein. Catheters that end up in smaller veins such as the azygos vein, resulting in a higher rate of complications such as perforations, thrombosis, and stenosis compared to those placed in the SVC. ⁵ Therefore, it is important to position the catheter tip in the correct position.

To answer this need, we previously designed a monorail technique that helps radiologists easily position the tip of the catheter at the appropriate location by inserting a 0.018-inch hair-wire after puncturing the port catheter with a 21-gauge needle. ⁶ However, with this technique, the hair-wire sometimes pushes the catheter out of its set position. Here, we introduce an improved push–pull monorail technique to resolve this issue and the results of our retrospective study on its feasibility and related outcomes in clinical practice.

Materials and methods

Patients

This study was approved by the appropriate institutional review board (IRB approval number: XC21RADI0104, date: July 22, 2021), and the requirement for informed consent was waived due to its retrospective study design as all the analyzed information was obtained from preexisting medical charts and records. Between December 1, 2018 and July 15, 2021, 5326 implantable port insertions were performed in two hospitals. Among the 5326 procedures, 472 involved insertions through the left IJV, with 464 being successful and excluded from the study. The other 8 patients (1.7%, 8/472) who were inserted with a left-sided implantable port experienced a complication during the routine procedure, and the push–pull monorail technique was applied. These eight patients made up the final study population, with two being male and six being female with a mean age of 60.1 years. We reviewed the electronic medical records (EMR) and picture archiving and communication system (PACS) data to determine why the left-sided approach was chosen over the right-sided approach for insertion. Three experienced interventional radiologists with at least four years of experience performed all of the insertion procedures. Baseline patient characteristics are summarized in Table 1.

Table 1.

Patient information.

Patient no.	Sex	Age	Underlying disease	Reason for left-sided port insertion
1	F	77	Ovary cancer	venous occlusion
2	F	48	Right breast cancer	space-occupying lesion
3	F	65	Left breast cancer	pre-existing central venous catheter
4	F	30	Right breast cancer	space-occupying lesion
5	M	53	Carcinoid tumor of lung	venous occlusion
6	M	72	Acute leukemia	pre-existing central venous catheter
7	F	80	Lung cancer	space-occupying lesion
8	F	56	Right Breast cancer	space-occupying lesion

Procedure: Routine implantable port insertion

According to past literature, an operator has several choices on how to insert the venous port. ⁴ In our institution, the modified upward-created pocket method is generally performed. ⁷ The left IJV is approached percutaneously with the Seldinger technique using a micropuncture set that is introduced sequentially under ultrasound guidance. A hair-wire is used to measure the intravascular distance from the assumed pocket site to the cavoatrial junction or right atrium under fluoroscopic guidance. The catheter is then cut to a length estimated based on the hair-wire, locked to a port hub and chamber, and connected to a tunneler. The catheter is tunneled under the subcutaneous tissue from the pocket site to the puncture site and after it is positioned properly, the port is placed inside the pocket. A peel-away sheath is then pushed over the guide wire, the wire is pulled out, and the catheter is pushed through the sheath.

Procedure: The monorail technique

Generally, when the peel-away sheath is inserted via the left IJV, the tip of the peel-away sheath is placed in the left brachiocephalic vein. If the catheter tip repeatedly gets stuck in the azygos vein when trying to insert it through the peel-away sheath, we apply the monorail technique. With the monorail technique, the distal end of the catheter is pulled out as much as possible, and the 21-gauge needle that was used to initially puncture the left IJV is again used to puncture the far distal portion of the catheter at an acute angle (Figure 1A). Because even if leakage from the puncture site occurs, it must occur within the blood vessel. A 0.018-inch hair-wire is inserted through the catheter lumen, and the catheter–hair-wire complex is pushed through until the catheter tip reaches the SVC or cavoatrial junction (Figure 1B).

Figure 1.

Implantable port insertion through the left internal jugular vein in a 72-year-old male. (A) The distal end of the catheter was retrieved and punctured with the 21-gauge needle used to create the initial puncture site. (B) To guide the catheter into the superior vena cava, a 0.018-inch. hair-wire was introduced into the catheter. (C) When attempts were made to remove the hair-wire, the catheter kept following the wire. (D) A microsheath was inserted to prevent catheter removal. (E) The microsheath stayed in place even after wire removal. (F) The microsheath was removed. The final fluoroscopic image demonstrates a properly implanted port with the catheter tip at the cavoatrial junction. (G) Completion venography confirmed the absence of contrast material leakage at the puncture site.

Procedure: The push–pull monorail technique

An additional procedure unique to the push–pull monorail technique that prevents catheter removal is the insertion of a microsheath along the microwire (Figure 1C and D and Figure 2). When removing the microwire, we push the microsheath so that the port catheter does not exit with the microwire (Figure 1E). After removing the wire, the remaining microsheath is removed. The entire insertion procedure is considered complete after we confirm on fluoroscopic imaging that the port has been positioned correctly with the catheter tip at the cavoatrial junction (Figure 1F). Completion venography is performed to verify that none of the contrast material has leaked through the puncture site into the catheter (Figure 1G).

Figure 2.

The push–pull monorail technique with the micropuncture set. The distal end of the catheter was pulled out as much as possible, and punctured with the 21-gauge needle. A 0.018-inch. hair-wire was inserted through the needle to form a catheter–hair-wire complex. The needle was removed and a microsheath was inserted along the hair-wire. Then, force was applied to the microsheath (push) while removing the microwire (pull). The remaining microsheath was removed after the wire was completely removed.

Analysis

Technical success was defined with the proper positioning of the catheter tip at the SVC or cavoatrial junction. Patients were followed for 2–32 months, with follow-up examinations focusing on symptoms that might suggest any leakage of chemotherapeutic agents. In addition, we reviewed all follow-up chest radiography to check for other potential complications such as catheter malposition.

Results

Eight patients received implantable ports with the monorail technique and the technical success rate was 100% (8/8). There were no incidences of immediate or delayed procedure-related complications. Three patients were alive with the implantable port still functioning at the end of the follow-up period. Two patients had their ports removed seven and 13 months after completing chemotherapy, respectively. Three patients died due to disease progression 2–30 months after being implanted with the port. To note, none of the patients had discernible symptoms that indicated there were chemotherapeutic agents leaking through the puncture site additionally created by the 21-gauge needle.

Discussion

Anatomic factors can potentially explain why left-sided ports tend to enter the azygos vein. The azygos vein enters the SVC at its posterior wall immediately after crossing from the posterior to the anterior cephalad to the origin of the right main bronchus. Therefore, the azygos vein connects to the posterior wall of the SVC at or near the confluence of the brachiocephalic veins to form the SVC. The left brachiocephalic vein curves around the great vessels from anterior to posterior. Therefore, a catheter traveling through the left brachiocephalic vein will head toward the confluence of the azygos vein. ⁵

Complications can occur if the catheter is inserted into the azygos vein. Therefore, the tip of the catheter should be relocated to the SVC-RA junction. To avoid this complication, we developed the monorail technique and demonstrated its advantages in a previous publication. However, when the monorail technique is applied, the catheter sometimes continues to follow the wire during its removal. This is believed to be caused by the frictional force between the catheter and the hair-wire. The wire can be removed with a snap to go around this issue, but this additional step requires longer fluoroscopy times and skill. To solve this fundamental problem, we used a microsheath to prevent the catheter from exiting along the wire using a microsheath and achieved good results. This method can be used not only for left-side insertions but also for any situation where the catheter does not thread well. For example, when the course of the right brachiocephalic vein is tortuous and the catheter enters the azygos vein, this method can be used to easily locate the catheter at the SVC-RA junction.

There are several limitations to this study. First, this was the retrospective design. Second, the study population was made up of only 8 patients who were followed for a relatively short period of time. However, because the push–pull monorail technique is relatively simple to perform without other repercussions for patients, it can be easily applied to other patients. Third, there is the possibility of leakage as this technique involves puncturing the catheter with a small 21-gauge needle. However, the needle is inserted at an acute angle and the resultant opening is very small and located in the distal part of the catheter at the level of the SVC or brachiocephalic vein. The likelihood of any of the infused chemotherapeutic agents leaking through this puncture is thought to be insignificant as liquids will only flow through the catheter tip unless it becomes obstructed. ⁸ In summary, the push–pull monorail technique overcomes the issue of catheter removal seen with the conventional monorail technique and does so without additional cost Its simplicity also suggests that the method can be used for more anatomically challenging conditions in the future.

In conclusion, the push–pull monorail technique can be used to achieve successful left-sided port implantations.