Thymoma Resection Using Subxiphoid Uniportal Approach

There are different types of anterior mediastinal tumors, such as thymoma, germ cell tumors, ectopic parathyroid tumors, and lymphoid tumors. Completeness of tumor resection has been considered the most important determinant of long-term survival, therefore surgical resection of these tumors should be both safe and radical. Subxiphoid access is a novel approach for anterior mediastinal tumor resection. To perform surgery via this access, specially designed long instruments are required. Subxiphoid access provides excellent visualization of the mediastinum. There are reports of prolonged port-site pain and chest wall numbness with single or multiple video-assisted thoracoscopic surgery (VATS), and hence subxiphoid is proposed as an alternative access to deal with this.

The subxiphoid approach is technically more demanding than VATS due to the longer subcutaneous tunnel, smaller operative angle, and more instrument interference. The presumed advantages are more mediastinal multiangle surgical exposure on both sides, less tissue trauma, swift recovery, minor wound infection, reduced operative time and blood loss, lower pain scores due to avoidance of damage to the intercostal nerves, and reduced length of hospital stay. As the subxiphoid incision is away from the breast, it is cosmetically more acceptable. Subxiphoid incision is a “true” thoracic wound, ie, the surgical wound is below the sternocostal triangle and above the diaphragm, therefore herniation of the viscera through the incision is rare.

Disadvantages of this approach:

In case of accidental bleeding during surgery, an emergency conversion to open the chest through sternotomy would be necessary. Also, the anterior mediastinal space is narrow, especially in obese patients, so the instruments may interfere with and crowd each other.

Patient Selection and Preoperative Evaluation
The patients who are candidates for this kind of surgery:

1. Clinically diagnosed anterior mediastinal tumor
2. Nonthymomatous myasthenia gravis
3. Thymoma of Masaoka stage 1-3
4. Normal heart and pulmonary function test
5. Body mass index (BMI) <30

Contraindications:

1. Large mediastinal tumors >5 cm
2. Masaoka thymoma stage IV
3. Enlargement of lymph nodes
4. Previous thoracic operation
5. Thoracic cage deformity
6. BMI >30
7. Cardiomegaly

Preoperative evaluation:

• Blood test
• Pulmonary function test
• Contrast-enhanced chest computed tomography scan
• Stabilization of myasthenia gravis before surgery

Operative Steps

Double lumen ventilation was used. The patient was positioned supine with abducted legs, which enables the exposure of both mediastinal sides with clear visualization of both phrenic nerves. The sternal elevation retractor with one hook was used for elevation of the lower sternum edge. Usage of long curved and sturdier instruments is extremely beneficial.

A subxiphoid incision was made 3-4 cm below the lower angle of the sternum. The medial parts of both abdominal rectus muscle were cut transversely with electrocautery to expose the xiphoid process and the costal arches bilaterally. The next step was elevation of the lower angle of the sternum with a hook connected to the modified sternal elevation retractor, which enlarged the space between the chest wall, diaphragm, and the pericardium through which the chest cavity was entered. The authors used electrocautery to dissect the mediastinal pleura in order to get access to the chest cavity on both sides. They introduced the thoracoscope via the subxiphoid wound.

The thymus was dissected from caudal toward the cranial direction (toward the brachiocephalic vein) and both phrenic nerves laterally. In the case of large volume of the mediastinal fat, it is very helpful to transfer the whole dissected specimen to the opposite pleural cavity, which clears the view of the mediastinum. En bloc removal of the whole thymus, perithymic fatty tissue, both epiphrenic fat pads, and the sheets of right and left anterior mediastinal pleura is important for a radical resection of the tumor. The right and left upper poles of the thymus are dissected from the lateral sides. The left brachiocephalic vein was visualized and dissected, and the thymic veins are divided after applying a hemlock clip.

The authors did not place any extra ports, and the operative time was 45 minutes. After completing the procedure, a 28 F chest tube was inserted through the same subxiphoid wound. No postoperative arrhythmia or bleeding was detected. The patient was discharged on the third postoperative day and had an uneventful recovery. Her postoperative pain scores (Wong-Baker FACES) on days one, two, and three were 3-2-1.

List of any unusual instrumentation:

1. Curved long suction
2. Mixtard forceps
3. Curved ring forceps
4. Harmonic scalpel knife
5. Long electrocautery hook

Tricks, Tips, Pitfalls, and Catastrophic Events

1. The patient is positioned supine with abducted legs, which enables the exposure of both mediastinal sides with clear visualization of both phrenic nerves.
2. The sternal retractor enables visualization of superior mediastinal structures up to the inferior poles of thyroid gland.
3. Harmonic scalpel is used for dissection and hemostasis at the same time.
4. Usage of long curved instruments is extremely beneficial in both dissection and suction, used also for retraction and controlling bleeding.
5. Bleeding of innominate vein or from internal thoracic veins.
6. Crisis of myasthenia gravis.
7. Pericarditis.
8. Phrenic nerve palsy.
9. Chyle leak.

The authors used a small tidal volume to let the mediastinum drop into the dependent nonoperative side. Moreover, carbon dioxide insufflation can be helpful in providing more space in the chest cavity, thus improving the view and decreasing the stress on the rib cage.

Conclusion
The subxiphoid uniportal approach for thymoma tumor resection is safe, and oncological radical resection is achievable.

Suggested Reading

1. Numanami H, Yano M, Yamaji M, et al. Thoracoscopic thymectomy using a subxiphoid approach for anterior mediastinal tumors. Ann Thorac Cardiovasc Surg. 2018;24(2):65-72.