Traducción a este idioma está en marcha. Entretanto, a fin de facilitar la comprensión de WeBSurg a su idioma, hemos utilizado Microsoft® Translator para traducir algunos términos que aún no han sido validados por nuestro equipo editorial.

Robotic assisted thymectomy for the management of autoimmune myasthenia gravis

  • Abstract
    We present the case of a 16-year-old female patient who has had an autoimmune myasthenia gravis for 8 months. Symptoms are generalized to her four arms. Anti-acetylcholine antibodies and the therapeutic test of Mestinon® (Pyridostigmine) are positive. In recent months, her symptoms worsened with the onset of swallowing disorders. Immunoglobulin treatment was poorly effective and was complicated by the appearance of jaundice. CT-scan showed a mediastinal thymic hyperplasia. Thymectomy is indicated. To do so, a left thoracoscopy is performed and assisted by means of the Da Vinci™ robot. Pathological findings demonstrated the presence of a lymphoid thymic hyperplasia. The use of the Da Vinci® robot for this type of intervention has been recognized many years ago now with the works of Federico Rea and Jens Ruckert among others. The advantage of this technique is the possibility to proceed with a radical thymectomy enlarged to the mediastinal fat exactly in the same way as for a median sternotomy, which is the standard technique. When compared to thoracoscopy, the advantage stems from 3D vision, segmentation of the operator’s movements, and exceptional maneuverability of the instruments which have 7 degrees of freedom. These instruments allow for an access to the lower cervical area without the use of a cervicotomy. The choice of the left side is explained by the need to identify the phrenic nerve’s position, which is more difficult to predict than the right nerve’s position, which can be easily identified on the right lateral aspect of the superior vena cava.
  • 00'18" Patient position
    The female patient is placed in a dorsal decubitus position. Her left hemithorax is elevated by means of a cushion. Her left arm is misaligned with the operating table by 10cm. This arm is positioned as posteriorly as possible to provide sufficient space for the robot’s right arm.
  • 00'38" Ports position
    Three ports are placed and a robot with three arms is used. The first port is placed in the 5th intercostal space on the anterior axillary line; it will accommodate the robot’s video camera. The position of the two other ports will then be determined. An 8mm robotic port is placed in the 5th intercostal space to accommodate the left arm on the parasternal line and another port is placed in the third intercostal space in the anterior axillary line. The robot is positioned at a 45-degree angle as compared to the position of the patient’s head.
  • 01'14" Staff position
    The assistant stands at the patient’s table. A scrub nurse and the surgeon stand at the console. The equipment for anaesthesiology should be placed well away from the table with sufficiently long extension cords for perfusion tubes and for the different monitoring cables.
  • 01'32" Organ position
    The anatomical position of the thymus is completely retrosternal, posterior to the manubrium sterni, with the two ascending thymic horns. In order to facilitate access to these two thymic horns, the patient’s head is retracted by means of a slight anterior flexion.
  • 01'51" Mediastinal pleura incision
    The intervention begins with delimitation of the operative area using a low frequency monopolar scalpel (20 Watts) in order not to injure the phrenic nerve. The assistant’s hand still remains on the patient’s belly in order to monitor the amount of electric sparks that may be absorbed by the phrenic nerve. The first operative step consists in dividing the mediastinal pleura along the phrenic nerve and the mammary pedicle anteriorly. The phrenic nerve is retracted posteriorly. The thymus is lifted up and dissection is performed from caudally to cranially until the left upper thymic horn is identified. Division of the mediastinal pleura is pursued anterior to the phrenic nerve retracted posteriorly. Here, division of the parietal pleura facing the mammary pedicle is initiated in order to delimitate the anterior part of the dissection.
  • 02'51" Thymus dissection
    The thymic tissue is well visible here. Difference in texture between the thymic tissue - hyperplastic in our present case, and the mediastinal adipose tissue can be clearly observed. Freeing is continued on the pericardial plane caudally and the innominate vein can then be identified. The thymus courses behind the phrenic nerve and sometimes until the aortopulmonary window. One can clearly see our position within the adipose tissue, and posteriorly the thymic horn ascending to the cervical area is visible. The innominate venous trunk starts to clearly appear. A thymic vein will be coagulated without any problem. Clipping of this thymic vein is almost always unnecessary. The thymus is firmly positioned against the ceiling of the rib cage, hence posteriorly to the sternum. Freeing of the innominate venous trunk is carried on in search of thymic veins. It is essential not to tear them off as the feeling of traction is not marked, as there is no robotic feedback. It is essential to prevent any potential traction on the vein. The superior portion is slightly freed in order to better isolate the horn and exert caudal traction on it. The pleural incision is completed anteriorly. The left lower thymic horn is held by the grasper and the entire thymic gland is pushed downwards and freed retrosternally. Here, the lower thymic horn is followed. At the end of the procedure, the optical system will be replaced by a 30-degree scope, which will allow for a better visualization of the right lower portion of the thymus, and more particularly the portion proximal to the right phrenic nerve that will be slightly uneasy to control. The extremely good maneuverability of robotic instruments makes way for a perfect adaptability to every situation. This eliminates the need for port position change and facilitates access to the least accessible locations.
  • 06'44" Right phrenic nerve control
    The contralateral lung can be seen in transparency. The mediastinal pleura has not been opened yet. The superior part of the thymectomy will be achieved as caudal traction is placed on the thymus. Slight flexion of the patient’s cervical area facilitates the descent of the two upper thymic horns. Here is the most subtle part of the intervention. Dissection of the left superior horn is started in the cervical area. This dissection is the most difficult one to achieve as the terminal part of the horn at the thyroid’s lower pole must be resected. Progressive traction must be performed by means of the left forceps and using slight cauterization in a region difficult to access. However, thanks to the robotic instruments, the region is much easier to access. Here, the robotic right arm’s movement is particularly valuable at this stage of the procedure. The left superior horn is dissected. Dissection of the right horn is initiated using a similar technique, namely using progressive slight traction on the left forceps. This forceps helps to retract the thymic horn caudally. Here, the demarcation between the thymic tissue and the adipose tissue is clearly visible. Dissection of the superior horns is now complete and the procedure can be continued with the freeing of the vascular pedicle. The thymic horn has been divided until its apex. The demarcation line between the thymic tissue and the adipose fibrotic tissue can be clearly seen. Dissection is continued until the right upper thymic horn is reached. Freeing of the innominate vein can be completed. Here, dissection of the two upper horns has been completed and the mediastinal pleura can be opened in order to complete the resection with the right portion of the thymus. Visual control of the phrenic nerve’s position is achieved through the 30-degree scope. Freeing of the right lower part of the thymus is performed. Here, the mediastinal pleura is opened. It can be divided. Here, the extremity is reached. Opening of the mediastinal pleura is completed in order to perfectly control the position of the phrenic nerve. Here, the phrenic nerve becomes visible. The resection is now complete as the superior vena cava has been reached. The phrenic nerve comes into sight. The intervention is completed with extraction of the specimen into an Endobag™ and a pleural drain is placed across the two pleuras opposite to the thymic fossa.
  • Related medias
    We present the case of a 16-year-old female patient who has had an autoimmune myasthenia gravis for 8 months. Symptoms are generalized to her four arms. Anti-acetylcholine antibodies and the therapeutic test of Mestinon® (Pyridostigmine) are positive. In recent months, her symptoms worsened with the onset of swallowing disorders. Immunoglobulin treatment was poorly effective and was complicated by the appearance of jaundice. CT-scan showed a mediastinal thymic hyperplasia. Thymectomy is indicated. To do so, a left thoracoscopy is performed and assisted by means of the Da Vinci™ robot. Pathological findings demonstrated the presence of a lymphoid thymic hyperplasia. The use of the Da Vinci® robot for this type of intervention has been recognized many years ago now with the works of Federico Rea and Jens Ruckert among others. The advantage of this technique is the possibility to proceed with a radical thymectomy enlarged to the mediastinal fat exactly in the same way as for a median sternotomy, which is the standard technique. When compared to thoracoscopy, the advantage stems from 3D vision, segmentation of the operator’s movements, and exceptional maneuverability of the instruments which have 7 degrees of freedom. These instruments allow for an access to the lower cervical area without the use of a cervicotomy. The choice of the left side is explained by the need to identify the phrenic nerve’s position, which is more difficult to predict than the right nerve’s position, which can be easily identified on the right lateral aspect of the superior vena cava.