Asian Cardiovasc Thorac Ann 2006;14:e108-e110
© 2006 Asia Publishing EXchange Ltd
Thoracoscopic Thymectomy in a Previous Sternotomy
Soumil Vyas, FRCS,
T Agasthian, FRCS,
Meng Huat Goh, MMed,
S Shankar, FRCS1
Department of Thoracic Surgery
1 Department of Cardiovascular and Thoracic Surgery, National Cancer Center and Singapore General Hospital, Singapore
For reprint information contact: Soumil J Vyas, FRCS Tel: 91 22 2415 0581 Fax: 91 22 2410 2577 Email: soumil_v{at}yahoo.com, 161/162, Riddhi Apartments, 7th floor, 57, North Sewree Wadala Scheme, Road no 10, Wadala, Mumbai 400 031, India.
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ABSTRACT
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A video assisted thoracoscopic surgery (VATS) thymectomy is a viable alternative to conventional open thymectomy in myasthenia gravis (MG). A previous operation in the same anatomical region is generally considered a relative contraindication to any minimally invasive approach in the same area. Few cases of VATS on previously operated chests have been reported. We report a case of a VATS thymectomy in a patient who had undergone two previous sternotomies for cardiac disease.
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INTRODUCTION
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Thymectomy is an established therapy for patients with generalized myasthenia gravis (MG), even though there is no randomized evidence comparing surgery to medical treatment. It is known that over 70% of patients with MG post-thymectomy experience symptomatic remission, and in 33% the remission is complete.1
Video assisted thoracoscopic surgery is a relatively new approach in thoracic surgery and on account of certain inbuilt benefits of minimally invasive surgery, is a viable and safe alternative to conventional open thoracotomy. While a previous thoracotomy/sternotomy may make this a challenging procedure, thoracoscopic surgery in such a patient may not be an absolute contraindication.2 As a dedicated thoracic unit we herein report a case of VATS thymectomy for generalized MG, in a patient who had two previous sternotomies for rheumatic valvular disease.
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CASE REPORT
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A 52-year-old Chinese housewife with MG was referred by neurophysicians for a thymectomy. She suffered from rheumatic heart disease (RHD) with mitral and aortic stenosis and regurgitation and mild pulmonary hypertension. The patient was diagnosed with myasthenia gravis (Modified Osserman Classification – Class 3) in November 2001 and was on regular medication (pyridostigmine). In 1975 she had a closed mitral valvotomy for the mitral RHD, followed by an open repair of the mitral valve performed in 1985. In August 2001 she suffered a left hemiparesis and recovered completely. She had been on anticoagulants (warfarin) since. A computed tomography (CT scan) of the chest showed a prominent enlarged thymus (Figure 1
). The CT scan also showed a good distance between the sternum and the heart. It was quite obvious on the scan, and was later confirmed during surgery, that the sternum was not adherent to the pericardium or heart, in spite of her previous sternotomies. A clinicoradiologic diagnosis of MG secondary to thymic hyperplasia was made which was confirmed by pathology. The two previous sternotomies for RHD made the surgery through median sternotomy a difficult option. A third sternotomy would have encountered the significant problems of cardiac adhesions in the immediate retrosternal area. The problem of securing a good sternal closure and its subsequent uneventful healing was a source of concern. Should she have required a valve replacement in the future this would have added to the morbidity of a fourth sternotomy. Therefore we were compelled to consider an alternative option in order to avoid sternotomy. We aggressively explored the option of a minimally invasive yet equally effective approach for the thymectomy. The obvious alternative was that of a VATS thymectomy.
These issues were discussed at length with the patient and her family. The patient was admitted a week in advance to facilitate thorough preoperative preparation, and to optimize her for general anesthesia and surgery. Her coagulation profile was corrected after withdrawing the aspirin and warfarin. Heparin was withdrawn 6 hours prior to surgery. General anesthesia was given with single lung ventilation using a double lumen endotracheal tube. The patient was put in a 45 degree (right up) off center position. Video assisted thoracoscopic thymectomy was performed through a right-sided approach. The right-sided approach was adopted as there were minimal adhesions in this region and a better visualization of the thymus and anterior mediastinum was achieved through this approach. The camera (30 degree lens) was inserted via a 15 mm port through the 7th intercostal space in the anterior axillary line and two further working 10 mm ports were created in the 6th intercostal space midaxillary line and in the 3rd intercostal space anterior axillary line (Figure 2). The magnified view provided by the camera also further aided in more accurate visualization and identification of the mediastinal structures, which facilitated the thymectomy. The pericardium was noted to be partially closed from the previous cardiac surgeries. This greatly facilitated the identification and dissection of the thymus. Adhesions between the sternum and the pleura/pericardium anteriorly were lysed and an access was obtained to the root of the neck and thoracic inlet. Systematic dissection was carried out using a harmonic scalpel and an en bloc thymectomy was performed (Figure 3). The surgery took 4 hours 50 minutes. Blood loss was minimal. Post thymectomy visualization of the mediastinum did not show any residual thymic tissue.
The patient was extubated immediately after surgery. Her postoperative recovery was uneventful. The anticoagulants were gradually resumed to the desired levels. Histopathology confirmed the thymus to be hyperplastic with prominent Hassall corpuscles and lymphoid aggregates and reactive germinal centers.
The patient has been on a regular follow-up for the last 10 months since the thymectomy. She has had a gradual and sustained improvement in symptoms. Although she continues to be on pyridostigmine in reduced doses, she has had symptomatic improvement from Osserman Class 3 to Osserman Class 1.
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DISCUSSION
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The best surgical approach to thymectomy remains controversial. Available options include a median sternotomy with or without a transverse cervical extension, partial sternotomy, transcervical approach and VATS. For maximal benefit, thymectomy should be complete.1 Jaretzki suggested the concept of "maximal" thymectomy advocating a mediastinal exenteration, inclusive of removal of ectopic thymic tissue.3 Although not ratified in any randomized trial the benefit and remission with the more conservative approaches is similar to the more radical approaches.1 Video assisted thoracoscopic surgery has been successfully used for thymectomy, although its role for MG has been doubted.4 Video assisted thoracoscopic surgery combines the minimal surgical trauma of a transcervical approach with the excellent visualization of the transmediastinal approach. However, dissection of the superior horns particularly in a hypertrophied thymus may be difficult through a VATS approach and this may make VATS thymectomy a demanding operation.4 Results of VATS are comparable with the more established approaches.1,4,5 For safety and a complete operation, it is recommended that the procedure is to be undertaken by experienced thoracic surgeons.3,5
Thoracoscopic thymectomy has been reported after previous conventional open trans-sternal or trans-cervical approaches.6 Pompeo et al6 reported thoracoscopic completion thymectomy performed on eight patients with refractory myasthenia previously treated with conventional surgery. They described the conventional approach as having a higher morbidity and suggested that the thoracoscopic approach may be safer with respect to recovery with probably a lesser incidence of damage to the vital structures. We would agree with them as regards to the obvious patient advantages as similar clinical benefits were seen in our patient. In addition, good symptomatic improvement was demonstrated in our patient similar to that seen by Pompeo and colleagues.
Patient advantages include reduced pain, faster postoperative recovery and improvement of pulmonary function, with excellent cosmesis. The procedure is more suited for high-risk surgical candidates5 like ours. Concerns about using VATS in patients with previous sternotomies arise on account of poor visualization secondary to adhesions from previous surgery and bleeding from the adhesiolysis. Whilst a conventional 15 mm port was employed, with greater experience and confidence an attempt could be made to use smaller ports. Amid concerns of inherent risk of damage to vital structures,2 Yim reported 23 cases of VATS procedures performed on previously operated chests and showed that the procedure is feasible.2 Historically, previous chest surgery had been considered a relative contraindication to VATS.2
Experience of the surgeon and the nature of the operation are important factors in deciding a VATS approach on a previously operated chest.2 The complexity of the procedure suggests that it be undertaken only in dedicated thoracic units by experienced surgeons well conversant with thoracoscopic surgery. Video assisted thoracoscopic surgery on previously operated chests may be safe if attention is paid to details. The magnified view provided facilitates adhesiolysis in the closed chest.
This case demonstrates success with a VATS thymectomy in a patient with two previous sternotomies. The associated comorbidites made the procedure more imperative to facilitate a quick recovery. This is an effective approach for obtaining an uneventful recovery in the high-risk patient.
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REFERENCES
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- Yim AP, Kay RL, Ho JK. Video-assisted thoracoscopic thymectomy for myasthenia gravis. Chest 1995;108:1440–3.
- Yim AP, Liu HP, Hazelrigg SR, Izzat MB, Fung AL, Boley TM et al. Thoracoscopic operations on reoperated chests. Ann Thorac Surg 1998;65:328–30.[Abstract/Free Full Text]
- Jaretzki A 3rd, Penn AS, Younger DS, Wolff M, Olarte MR, Lovelace RE, et al. Maximal thymectomy for myasthenia gravis. Results. J Thorac Cardiovasc Surg 1988;95:747–57.[Abstract]
- Mineo TC, Pompeo E, Lerut TE, Benardi G, Coosemans W, Nofroni I. Thoracoscopic thymectomy in autoimmune myasthenia: results of left-sided approach. Ann Thorac Surg 2000;69:1537–41.[Abstract/Free Full Text]
- Yim AP, Lee TW, Izzat MB, Wan S. Place of video thoracoscopy in thoracic surgical practice: Review. World J Surg 2001;25:157–61.[Medline]
- Pompeo E, Nofroni I, Iavicoli N, Mineo TC. Thoracoscopic completion thymectomy in refractory nonthymomatous myasthenia. Ann Thorac Surg 2000;70:918–23.[Abstract/Free Full Text]
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Thorascopic mediastinal resection after median sternotomy and mediastinotomy.
Ann. Thorac. Surg.,
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[Abstract]
[Full Text]
[PDF]
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ABSTRACT
INTRODUCTION
