Transcervical Extended Mediastinal Lymphadenectomy

Patient Selection

Transcervical extended mediastinal lymphadenectomy (TEMLA) was developed to enhance lymph node sampling obtained by conventional mediastinoscopy¹. Even though mediastinoscopy is accurate, false positive and false negative results still occur². In an initial large series, the performance of TEMLA was better than routine mediastinoscopy^3, 4. However, given the advent of positron emission tomography – computerized tomography (PET-CT), the usefulness of surgical mediastinal staging for early clinical stage lung cancer patients with negative metabolic imaging is controversial⁵. Also, since a large randomized, controlled trial demonstrated no benefit of lymphadenectomy in early stage disease (ACOSOG Z0030), routine TEMLA for stage I NSCLC seems unjustified. Therefore, in our practice, TEMLA is performed in situations where detection and resection of occult metastatic disease in mediastinal lymph nodes has the highest perceived benefits for patients. Tumors in such patient groups have the following characteristics:

• Large size (> 7cm)
• Imaging findings that suggest aggressive disease (central necrosis, satellite nodules and high PET avidity (Standard Update Value, SUV-max > 6)
• N1 disease suggested by CT or PET
• Two synchronous, presumed primary lesions
• IIIA stage requiring neoadjuvant therapy

No definite contraindications exist to TEMLA except permanent end tracheostomy. This procedure can be performed in any patient regardless of habitus; however, thin patients with no neck extension limitations and wide thoracic inlets have more favorable anatomy. Relative contraindications include:

• Previous mediastinoscopy or extensive head and neck surgery involving mediastinal dissection
• Extensive innominate artery calcification (embolic risk)
• Previous median sternotomy
• Extensive superior mediastinal fibrosis such as from radiation therapy

Operative Steps

The patient is positioned supine with a roll under the shoulder and the neck extended. This can be facilitated by dropping the head-piece of the operating table. The patient may be intubated with either a single or a double-lumen tube; the latter does not interfere with the procedure as long it is secured well and taped out of the way. A right radial arterial line is placed to monitor innominate artery compression. The arms are then tucked to make room for the Rultract™ (Rultract Inc, Cleveland, OH) retractor. The neck and anterior chest are prepped and draped in a routine manner for mediastinoscopy from the chin to below the xiphoid process.

A transverse collar incision is made about 1 cm superior to the sternal notch to a length of 6-8 cm (Video 1 below). Bilateral anterior jugular veins are divided and sub-platysmal flaps are developed superiorly and inferiorly. The strap muscles are separated all the way to the sternum. At this point, retrosternal dissection is performed to make space for the hook of the Rultract™ retractor. Elements for this retractor system frequently exist in hospitals that perform coronary artery bypass grafting because it is used with a single post to expose the mammary artery. We connect a bridge to posts on both sides of the patient to allow maximal lift. Alternatively, retractor systems that are used for cervical thymectomy can be used as well. The thyrothymic ligament is divided bilaterally. The carotids on both sides are dissected and the recurrent laryngeal nerves are identified and protected. The Rultract™ retractor is set up and a hook is used to elevate the sternum. The anesthesiologist supports the head and neck during this maneuver and adjusts the head support once the elevation is complete. A plane of dissection is established anterior to the right carotid and is followed to the innominate artery; this plane is used to separate the innominate artery from the brachiocephalic veins. During this dissection, level 1 lymph nodes can be dissected out.

The right paratracheal space dissection is performed next (Video 2 below). The plane anterior to the innominate artery is developed and extended inferiorly to the the artery into the “TEMLA path” that is bounded by the pleura laterally and the right lateral trachea medially. The space is visualized well by lateral retraction with a narrow malleable retractor and medially by a peanut sponge. It is important to note that full mobilization of the right carotid and brachiocephalic artery is what enables this exposure which is much better than what is possible with a mediastinoscope, particularly for the 2R station. The lymph node packet is mobilized by blunt dissection. Any vascular attachments are divided using a 5 mm Ligasure™ device (Covidien Inc, Mansfield, MA). Mobilization of the superior packet leads to much better visualization of the deeper lymph nodes. Use of 2.5 X loupes and a headlight enhance the visual field, and the latter is indispensible. Occasionally, a 5 mm thoracoscope can also be used to improve visualization. A combination of blunt dissection and Ligasure™ are used to evacuate the right paratracheal space to the point where the right pleura, the superior venacava, the azygous vein and the right mainstem bronchus are clearly visualized.

The subcarinal space dissection is performed next (Video 3 below). The pretracheal fascia is divided and the pretracheal plane of dissection is developed to the carina. Further dissection separates the right main pulmonary artery from the carina. Once adequate separation is accomplished, the Wolf mediastinoscope is inserted in the space between the pulmonary artery and the carina so that the upper lip of the mediastinoscope is beneath the pulmonary artery. It is only after this is accomplished that the blades of the mediastinoscope are spread both in a vertical direction and at an angle. This separation enables enough visualization and space to work with two thoracoscopic instruments under direct vision. The edge of the lymph node packet is grasped with the thoracoscopic tissue graspers and blunt dissection is used to separate it from the esophagus. The bronchial artery is divided using a 5 mm Ligasure™. Further blunt and Ligasure™ dissection is used to dissect off the packet from bilateral mainstem bronchi and the packet is delivered en-bloc. The operating mediastinoscope allows passage of multiple instruments so that the first assistant can provide sufficient suction and countertraction to avoid vascular injury.

The left paratracheal space is dissected next (Video 4 below). Dissection is started in the left neck with the identification of the recurrent laryngeal nerve. The nerve is followed into the mediastinum. Along the way, the left paratracheal lymph nodes are bluntly dissected out. No cautery or any other form of energy is used for hemostasis on the left side to avoid injury to the nerve. Annoying bleeding is controlled with topical anticoagulation agents. Compared to the right paratracheal and subcarinal lymph node regions, there are usually fewer lymph nodes in the left paratracheal region. This dissection can be carried out using the Wolf mediastinoscope; however, it is often performed under direct vision just after the right paratracheal dissection and before the subcarinal packet is approached. Usually, the scope is necessary for the distal 4L nodes.

Aorto-pulmonary window and para-aortic lymph nodes (Levels 5/6) are addressed next. While dissection of these lymph nodes via TEMLA is feasible and well described, they are more easily accessed via left VATS. Therefore, we reserve dissection of these lymph nodes via VATS for all left sided lesions at the time of definitive resection – also malignant involvement of isolated lymph nodes in this station does not deter us from resection at the same time as long as the lymph nodes are technically completely resectable. For right sided lesions, involvement of lymph nodes in this station in the absence of subcarinal or left paratracheal lymph node involvement is extremely unlikely, therefore the dissection of these lymph nodes does not add much to staging information.

Preference Card

• Video Mediastinoscope by Dahan/Linder, with distal and parallel dilating spatula, WL 160 mm with fixed eyepiece (Catalogue No. 8783.721, Richard Wolf Medical Instruments Corporation, Vernon Hills, IL; www.richardwolfusa.com )
• Olympus High Definition camera head used with the above mediastinoscope (Product # OTVS7) along with Exera II CV-180 high-definition processor and Exera II CLV-180 light source and high-definition monitors (Olympus America Inc, Center Valley, PA)
• Rultract retractor (Rultract Inc, Cleveland, OH) spline tip, double bend square base combination clamp, bilateral set (product # 4100-SPLN-B2810) with ratchet assembly and snap clip (product # 4100-IMR-41) and xiphoid rakes (product # 4100-72)
• Malleable retractors (Product # BT 755, BT 752, BT 751; Aesculap Inc. Center Valley, PA)
• 5 mm Ligasure™ device (LS 1500; Covidien, Mansfield, MA)
• Thoracoscopic DeBakey tissue graspers (Catalog # JFSDN225, JFSD225; Edwards Lifesciences, Irvine, CA)

Tips and Pitfalls

• Adequate time should be spent creating flaps and dissecting structures before the application of the retractor – any shortcuts tend to decrease exposure significantly
• In situations in which the exposure is limited, especially in the obese patient with a short neck, a 5 mm thoracoscope greatly facilitates visualization of the right paratracheal space
• We prefer performing anatomic resections at the same time as the TEMLA – delaying the definitive resection to a later date makes a thoracoscopic lobectomy challenging and may lead to conversion to an open case due to significant scarring from the TEMLA dissection. For the same reason, no pro-coagulant materials such as gelfoam and thrombin or surgical are left in-situ if resection is planned at a later date – meticulous hemostasis with a 5 mm Ligasure™ device is preferred.

Results

The safety of TEMLA is reported as being good, although all published reports are from a single European center. The following complication rates were reported in a large series that looked at TEMLA in previously untreated patients – temporary laryngeal nerve palsy (2.3%), permanent laryngeal nerve palsy (0.8%), pneumothorax (0.4%), pleural effusion (4.3%) and asymptomatic mediastinal widening (60%). In our experience, which includes patients after neoadjuvant therapy (N=25; unpublished data), TEMLA was successfully performed in over 90% of patients with no side effects attributable to the procedure. Our operative times are falling with experience, and are now routinely between 1 and 2 hours. VATS lobectomies can be performed safely at the same time; in fact, the extensive dissection facilitates thoracoscopic lobectomy/pneumonectomy and also saves time by avoiding the need to dissect these stations by VATS. In terms of staging accuracy, the results are stellar both in patients without neo-adjuvant therapy and in patients after neo-adjuvant therapy, although published results are from a single center^{3, 6}. This promising technique deserves more extensive evaluation in a multi-institutional fashion and for specific clinical situations.

References

1. Kuzdzal J, Zielinski M, Papla B, et al. Transcervical extended mediastinal lymphadenectomy--the new operative technique and early results in lung cancer staging. Eur J Cardiothorac Surg 2005; 27(3):384-90.
2. Patterson GA, Ginsberg RJ, Poon PY, et al. A prospective evaluation of magnetic resonance imaging, computed tomography, and mediastinoscopy in the preoperative assessment of mediastinal node status in bronchogenic carcinoma. J Thorac Cardiovasc Surg 1987; 94(5):679-84.
3. Zielinski M. Transcervical extended mediastinal lymphadenectomy: results of staging in two hundred fifty-six patients with non-small cell lung cancer. J Thorac Oncol 2007; 2(4):370-2.
4. Kuzdzal J, Zielinski M, Papla B, et al. The transcervical extended mediastinal lymphadenectomy versus cervical mediastinoscopy in non-small cell lung cancer staging. Eur J Cardiothorac Surg 2007; 31(1):88-94.
5. Meyers BF, Haddad F, Siegel BA, et al. Cost-effectiveness of routine mediastinoscopy in computed tomography- and positron emission tomography-screened patients with stage I lung cancer. J Thorac Cardiovasc Surg 2006; 131(4):822-9.
6. Zielinski M, Hauer L, Hauer J, et al. Non-small-cell lung cancer restaging with transcervical extended mediastinal lymphadenectomy. Eur J Cardiothorac Surg 2010; 37(4):776-80.