MMCTS
(March 24, 2005). doi:10.1510/mmcts.2004.000422
Copyright © 2005 European Association for Cardio-thoracic Surgery
Procedure
Robotic video-assisted thoracoscopic thymectomy
Federico Rea*,
Giuseppe Marulli and
Luigi Bortolotti
Division of Thoracic Surgery, University of Padua, via Giustiniani 2, 35128 Padua, Italy
* Corresponding author: * Tel.: +39-049 821 2237, fax: +39-049 821 2249. E-mail: federico.rea{at}unipd.it
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Summary
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Presentation of a minimally invasive surgical technique for thymectomy in patients affected by myasthenia gravis (MG): robotic video-assisted thoracic surgery (VATS) is a surgical technique applied to perform thymectomy and remove the entire mediastinal fat through a left transpleural approach.
Key Words: Thymectomy • myasthenia gravis • robotic surgery
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Introduction and history
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Myasthenia gravis (MG) is an autoimmune disease that affects neuromuscular transmission and determines chronic weakness and fatigue at various levels of striated muscles.
Since 1941, when Blalock [1] first reported results of transsternal thymectomy in patients affected by MG, thymectomy has played a significant role constituting a widely accepted therapeutic option in the integrated management of MG.
Multiple techniques are described to remove the thymus in MG: transcervical thymectomy (basic or extended) [2], video assisted thoracoscopic thymectomy (VATS) [3, 4, 5] (classic or extended), transsternal thymectomy [6] (standard, extended or maximal), infra-sternal mediastinoscopic thymectomy [7].
Basic techniques for thymectomy enable a radical resection of the thymic gland through a single surgical approach; extended techniques associate more than one access (i.e. transcervical plus transsternal incision for maximal thymectomy proposed by Jaretzki [8]): the rationale of extended techniques is to obtain a complete resection of the visible thymus, the suspected thymus and cervical-mediastinal fat tissue (in which microscopic foci of thymic tissue may be contained) using a wide exposure.
In the last decade growing interest in minimally invasive surgical techniques has developed and recently robotic surgery has affirmed itself as an evolution of VATS.
The first surgical application of robotic technique was described by Loulmet and Reichenspurner in 1999: they performed a coronary by-pass [9, 10].
Subsequently robotic instruments were applied in other fields too and, in 2001, Yoshino [11] described the first robotic thymectomy in the treatment of small thymoma.
In 2003, Ashton [12] and Rea [13] published a case report on robotic thymectomy in MG using two different approaches: the former surgeon from Columbia University adopted a right-sided approach with completion of the operation through a left-sided approach, the latter from the University in Padua used a left-sided approach only.
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Surgical technique
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After neurological assessment, preoperative evaluation includes: a radiogram and computed tomography of the chest (Photo 1
) to verify feasibility of the surgical procedure. Surgery is performed in the following manner: the patient is under general anaesthesia and has a double-lumen endotracheal tube for selective single lung ventilation during the time of operation. In the surgical room (Schematic 1
) the patient is positioned left side up, 30 degrees on a bean bag. The arms of the ‘Da Vinci’ surgical system (MMCTSLink 17) are placed as follows: a camera port for the 3-dimensional 0 degree stereo endoscope is introduced through a 15 mm incision in the 5th intercostal space in the anterior portion of the midaxillary region; two additional thoracic ports are inserted through two additional 5 mm incisions in the 5th intercostal space on the midclavicular line and in the 3rd intercostal space on the anterior portion of the midaxillary region (Photo 2
).
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Schematic 1 Schematic planning in the surgical room: the patient is positioned on the surgical table, the ‘Da Vinci’ robotic system with the surgical cart and the surgeon's console are displaced.
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Photo 2 The thoracic ports are placed after the identification of the 5th and 3rd intercostal space and the arms of the ‘Da Vinci’ surgical system are attached to the ports and are operative.
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The left arm has an EndoWrist instrument that grasps the thymus; the right arm is an Endo-Dissector device with electric cautery function used to perform the dissection (Video 1
).
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Video 1 The surgeon sits at the console containing a display showing the images obtained with the endoscopic camera and any manipulators the surgeon uses to control the movements of surgical endoscopic instruments. This system is equipped with an intuitive 3-dimensional vision, a scale motion with tremor filtering and the EndoWrists with articulated movements permitting a full seven degree of freedom.
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During surgery the hemithorax is inflated through the camera port with CO2 ranging in pressure from 6 to 10 mmHg. CO2 inflation is very useful to obtain a clear view within the chest and to allow an easier dissection as it extends the mediastinal space.
After careful exploration of the mediastinal pleural space (Video 2
), the dissection of the fat tissue starts inferiorly at the left pericardiophrenic angle (Video 3
).
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Video 2 The mediastinal surface of the left pleural space is explored and the anatomic structures are identified: the pericardium, the phrenic nerve and the mammary vessels.
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Video 3 The operation starts with the removal of all the pericardio-phrenic angle fat tissue.
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The thymic gland is then divided from the retrosternal area (Videos 4
, 5
) and the left inferior horn of the thymus is subsequently isolated and dissected from the pericardium (Video 6
).
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Video 4 Following the removal of the pericardio-phrenic angle fat tissue, an incision is made from the bottom to the top of the retrosternal part of the mediastinal pleura.
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Video 5 The thymic tissue is dissected from the retrosternal space.
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Video 6 Isolation of the thymus from the pericardial surface is also performed from the bottom to the top.
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At the top of the mediastinum, the pleura is incised in the area delimited by the mammary vessels in the anterior limit and by the phrenic nerve in the posterior limit (Video 7
). At this point the lower part of the thymus is mobilized upwards and thymic tissue is dissected from the plane of the aorto-pulmonary window (Video 8
). The dissection continues in the right side with the visualization of the right mediastinal pleura and the right inferior horn (Video 9
).
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Video 7 At the apical level the pleural incision is made to reach the area that comprises the mammary vessels and the phrenic nerve.
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Video 8 Mobilization and dissection of the thymus gland is performed from the aorto-pulmonary surface.
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Video 9 The thymic gland is divided from the right mediastinal pleura and the right inferior horn is dissected.
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The isolation proceeds up to into the neck until the superior horns are identified and divided from the inferior portion of the thyroid gland (Videos 10
, 11
, 12
).
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Video 10 The cervical fat is dissected from the retrosternal and jugular region to identify the upper horns of the thymus.
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Video 11 The cervical left horn of the thymus is identified in the neck region. In this particular step it is important to carefully locate the innominate vein.
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Video 12 When the innominate vein is isolated, the cervical horns with an apical traction are dissected.
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The innominate vein is identified and the dissection continues along the border of the innominate vein up to the point where the thymic veins are identified, clipped and divided (Video 13
).
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Video 13 The thymic veins are visualized, doubly clipped and cut.
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The dissection finishes in the lower right side (Video 14
).
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Video 14 Dissection of the thymic tissue from the right mediastinal pleura is completed to remove the fatty tissue of the right pericardio-phrenic angle.
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The thymus gland, the anterior mediastinal and the neck's fatty tissue are radically resected and the specimen is placed in an Endo-Bag so it can be removed by trocar incision. After the haemostasis, a 28F drainage tube is inserted through the wound of the 5th intercostal space, the lung is reinflated and the other wounds are closed (Video 15
, Photo 3
).
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Video 15 The entire specimen is finally mobilized and an Endo-Bag is introduced in the pleural space through the inferior port. The thymus is placed in the Endo-Bag and taken out. A chest tube is placed and the lung is inflated under optical view.
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The patient is extubated in the operating room and, subsequent to an adequate period of observation, returns to the floor of surgical thoracic ward.
The chest drainage tube is removed 24 h after surgery and, if neurological evaluation is satisfactory, the patient is discharged 48–72 h after surgery.
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Results
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- Thymectomy in MG is an effective therapy that produces good clinical results.
- In literature the remission rate is comparable for the various surgical techniques proposed (Table 1).
- The transsternal approach is a widespread surgical technique for thymectomy. The main advantages are: an optimal exposition and dissection of the thymus and perithymic fat tissue and lower risks of vascular and nervous injuries. Some disadvantages include invasiveness of the approach and a longer hospitalization.
- The transcervical thymectomy, popularized by Cooper et al. [14], is a minimally invasive technique that is easily accepted by young patients and neurologists. The advantages are a short hospitalization, fewer complications and lower costs. The main criticism to this approach is related to the small space of access causing a crowding of instruments thus making surgical manoeuvres difficult and impossible to perform a thymectomy that extends to the perithymic fat tissue.
- VATS thymectomy through the left- or right-sided approach is a minimally invasive technique that permits a good visualization of the anterior mediastinum, achieving an extended thymectomy. The disadvantages are the 2-dimensional view of the operative field and the limited manoeuvrability of the endoscopic instruments.
- The robotic approach combines the advantages of minimally invasive techniques (fewer complications, minimal thoracic trauma, decreased postoperative pain, early improved pulmonary function, shorter recovery period and optimal cosmetic results [Photo 4
]) and the specific advantages as an intuitive 3-dimensional vision, a scale motion with tremor filtering and the endo-wrists with articulated movements permitting a full seven degree of freedom. These characteristics allow an accurate dissection, easier than classic VATS, particularly in the neck where the dissection is more difficult. The disadvantages of this approach include the initial high costs of the robotic system, the early increased operative time and the learning curves associated with robotic technology.
- Between April 2002 and October 2003, 24 patients underwent thoracoscopic thymectomy with the ‘Da Vinci’ surgical system at the Division of Thoracic Surgery of Padua. The operative time was 129 min (ranging from 60 to 240 min), no intraoperative mortality or complications were experienced; no conversion to median sternotomy and no more accesses were required. Post-operative complications occurred in two cases (8.3%): one patient had a chylothorax, another patient had a haemothorax caused by bleeding from one access and both were treated conservatively. Mean time of hospitaliza-tion after surgery was 2.7 days (ranging from 2 to 14 days).
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References
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- Blalock A, McGehee HA, Ford FR. The treatment of myasthenia gravis by removal of the thymus gland. JAMA 1941;117:1529
- Calhoun R, Ritter J, Guthrie T, Pestronk A, Meyers B, Patterson A, Pohl M, Cooper J. Results of transcervical thymectomy for myasthenia gravis in 100 consecutive patients. Ann Surg 1999;230:555–561[CrossRef][Medline]
- Mineo TC, Pompeo E, Lerut T, Bernardi G, Coosemans W, Nofroni I. Thoracoscopic thymectomy in autoimmune myasthenia: results of left-sided approach. Ann Thorac Surg 2000;69:1537–1541[Abstract/Free Full Text]
- Mack M, Landreneau R, Yim A, Halzelrigg S, Scruggs G. Results of video-assisted thymectomy in patients with myasthenia gravis. J Thorac Cardiovasc Surg 1996;112:1352–1360[Abstract/Free Full Text]
- Mantegazza R, Confalonieri P, Antozzi C, Novellino L, Ferr MT, Porta M, Pezzuoli G, Cornelio F. Video-assisted thoracoscopic extended thymectomy (VATET) in Myasthenia gravis. Ann NY Acad Sci 1998;841:749–752[CrossRef][Medline]
- Masaoka A, Yamakawa Y, Niwa H, Fukai I, Kondo S, Kobayashi M, Fujii Y, Monden Y. Extended thymectomy for myasthenia gravis: a 20-year review. Ann Thorac Surg 1996;62:853–859[Abstract/Free Full Text]
- Uchiyama A, Shuji S, Hiroyuki H. Infrasternal mediastinoscopic thymectomy in myasthenia gravis: surgical results in 23 patients. Ann Thorac Surg 2001;72:1902–1905[Abstract/Free Full Text]
- Jaretzki A 3rd, Wolff M. "Maximal" thymectomy for myasthenia gravis. Surgical anatomy and operative technique. J Thorac Cardiovasc Surg 1988;96:711–716[Abstract]
- Loulmet D, Carpentier A, D'Atelis N, Berrebi A, Cardon C, Ponzio O. Endoscopic coronary artery bypass grafting with the aid of robotic assisted instruments. J Thorac Cardiovasc Surg 1999;118:4–10[Abstract/Free Full Text]
- Reichenspurner H, Damiano RJ, Mack M, Boehm DH, Gulbins H, Detter C, Meiser B, Ellgass R, Reichart B. Use of the voice-controlled and computer-assisted surgical system Zeus for endoscopic coronary artery bypass grafting. J Thorac Cardiovasc Surg 1999;118:11–16[Abstract/Free Full Text]
- Yoshino I, Hashizume M, Shimada M, Tomikawa M, Tomiyasu M, Suemitsu R, Sugimachi K. Thoracoscopic thymomectomy with the Da Vinci computer-enhanced surgical system. J Thorac Cardiovasc Surg 2001;122:783–785[Free Full Text]
- Ashton RC, McGinnis KM, Connery CP, Swistel DG, Ewing DR, De Rose JJ. Totally endoscopic thymectomy for myasthenia gravis. Ann Thorac Surg 2003;75:569–571[Abstract/Free Full Text]
- Rea F, Bortolotti L, Girardi R, Sartori F. Tho-racoscopic thymectomy with the Da Vinci surgical system in patient with myasthenia gravis. Interact Cardiovasc Thorac Surg 2003;2:70–72[Abstract/Free Full Text]
- Cooper JD, Al-Jilaihawa AN, Pearson FG, Humphrey JG, Humphrey HE. An improved tech-nique to facilitate transcervical thymectomy for myasthenia gravis. Ann Thorac Surg 1988; 45:242–7[Abstract]
- Papatestas A, Genkins G, Kornfeld P, Eisenkraft J, Fagerstrom R, Pozner J, Aufses A. Effects of thymectomy in myasthenia gravis. Ann Surg 1987;206:79–88[Medline]
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Summary
Introduction and history
