Extrapleural cervico-manubriotomy and clavicular swing for the management of a mesenchymal tumour of the middle scalenus: an adapted anterior thoracic inlet approach

Abstract

Surgical approach for resection of tumours involving the thoracic inlet has largely been developed in the context of lung cancer of the superior sulcus. Therefore, initial anterior approaches included a thoracotomy associated with a longitudinal cervicotomy. Here, we describe a variation of the previously described anterior surgical approaches of the thoracic inlet that we performed for the resection of a primary mesenchymal tumour of the left middle scalenus muscle secreting fibroblast growth factor-23 responsible for tumour-induced osteomalacia. This approach allowed a safe control of the great vessels phrenic nerve and brachial plexus as well as a comfortable access to the middle scalenus muscle through an L-shaped incision with a cervico-manubriotomy without thoracotomy. The tumour was resected entirely with the middle scalenus. After 3 months of follow-up, the symptoms resolved entirely.

INTRODUCTION

Within the last 3 decades, there have been clear progress in surgical management of tumours involving the thoracic inlet. These progresses emerged from the development of anterior approaches allowing for the control of subclavian vessels and lower branches of the brachial plexus. In 1993, Dartevelle et al. [1] described a transclavicular approach showing the feasibility of safe en-bloc resection of primary lung cancer invading the thoracic inlet. In 1997, Grunenwald et al. [2] described a transmanubrial approach allowing preservation of the inner part of the clavicle. As these approaches to the thoracic inlet were initially developed for lung cancer resection, a thoracotomy was part of the approach. In case of primary tumour of the thoracic inlet like benign neural tumours, cervicotomy with limited sternotomy without thoracotomy has been described to perform safe tumoural resection [3]. Here, we had to perform a surgical resection of a rare primary tumour of the middle scalenus muscle requiring resection of the middle scalenus muscle, control of the subclavian vessels. As the tumour was strictly extrapleural, we considered an extrapleural approach. Hence, we modified the previously described anterior approaches to safely control great vessels and brachial plexus, obtain a comfortable access to the middle scalenus without associated thoracotomy or pleural effraction.

PREOPERATIVE EVALUATION AND INDICATION

The present approach was indicated for resection of a primary tumour of the left middle scalenus muscle corresponding to a tumour-induced osteomalacia in a 62 years old male. Clinical presentation was typical of a para-neoplasic tumoural secretion of fibroblast growth factor-23 with weight loss, multiple fractures, hypocalcaemia and hypophosphataemia. The positron emission tomography Ga-68 DOTATOC revealed a unique fixation into the caudal section of the middle scalenus muscle and magnetic resonance imaging confirmed the location of a 16 mm tumour and ruled out invasion of surrounding tissues (Fig. 1). As surgical resection is considered the only definitive treatment [4], we considered the indication for resection of the tumour along with the middle scalenus muscle because of the risk of local recurrence [5].

Figure 1:

Preoperative imaging. (A) Cervical magnetic resonance imaging. The tumour is pointed by the red arrow inside the middle scalenus muscle behind the subclavian artery. (B) DOTATOC positron emission tomography–computed tomography showing the intra middle scalenus unique location of the tumour secreting fibroblast growth factor-23.

OPERATIVE PROCEDURE

The patient is placed in a supine position with a bolster behind the shoulders and the head rotated rightward (Video 1). The incision is L-shaped with a longitudinal incision along the anterior border of the left sternocleidomastoid muscle and a longitudinal portion 3 cm below the inferior border of the clavicle. The pectoralis major muscle is divided through the costo-intercostal plan.

The first cervical steps consist in a dissection of the internal jugular and subclavian veins with ligature of the thoracic duct that allow full mobilization of the subclavian vein. The pre-scalenus ganglia are pushed externally and upward. Then the phrenic nerve is identified and the anterior scalenus muscle is transected giving access posteriorly to the subclavian artery and the brachial plexus, as well as to the cephalic part of the middle scalenus muscle and the mid and posterior portion of the first rib (Fig. 1).

The next steps give access to insertion of the middle scalenus muscle on the first rib. The manubriotomy is performed including a median longitudinal section and a right-angled transversal section ending in the first intercostal space. The manubrial corner with the anterior join of the clavicle can be mobilized forward and the internal mammary pedicle ligated and sectioned. Then the anterior cartilage of the first rib is sectioned along with subclavian muscle allowing full mobilization of the clavicle and easy access to the retro- and sub-clavicular structures. Then the middle scalenus muscle can be easily separated from its surrounding structures (Fig. 2).

Figure 2:

Operative steps. (A) Operative view of the section of the anterior cartilage of the first rib (**) after right-angled manubriotomy (*). (B) Operative view of the middle scalenus (**) behind the brachial plexus reclined upward and the phrenic nerve after section of the anterior scalenus muscle (*). (C) Operative view after middle scalenus resection. (D) Postoperative chest X-ray showing the L-shaped incision by staples and the preservation of the phrenic nerve function according to the anatomical position of the diaphragm.

Finally, the middle scalenus insertion is separated of the first rib through by using a periosteal elevator. The cephalic portion of the middle scalenus muscle is transected posteriorly to the brachial plexus and the mid scalene including the tumour are removed.

POSTOPERATIVE CARE AND MANAGEMENT

The postoperative course was marked by the onset of a cervical leakage of chyle at postoperative day 2 that required reoperation. The reoperation consisted in reopening of the cervical approach alone and to the completion of ligation of small lymphatic collaterals. As a decreased but residual persistent linkage was observed during reoperation, we ligated the thoracic duct at the inferior part of the mediastinum through a right video thoracoscopy with 2 access during the same operation. After the reoperation, the postoperative course was uneventful, and the patient was discharged home. The phospho-calcic perturbations and the preoperative bone pains entirely resolved after surgery.

DISCUSSION AND CONCLUSION

To our knowledge, middle scalenus primary tumour resection has not been described before. Here, we report a slightly modified version of classical thoracic inlet approaches initially described for lung cancer resection of the superior sulcus, thus including a thoracotomy. There are few differences compared to the Gruenwald approach [2]. The Grunenwald technic the first rib cartilage is removed whereas it is only sectioned in our approach. Second, Grunenwald describes that the subclavian muscle is let on the first rib along the subclavian vessels and that the dissection plan is along the clavicle. This probably aimed at maintaining sufficient non-tumoural margin for resection of tumours invading the firs rib. In our approach, the subclavian muscle is divided from the first rib and its insertion on the clavicle remains.

The specific postoperative surveillance should consider the risk of phrenic nerve palsy and chyle leakage through the cervical incision as the pleura is not opened. Voluntary pleural opening at time of tumour resection could be discussed and have the benefit to allow for chyle drainage through the pleura but exposes to the risk of postoperative pleural effusion and chest tube placement.

Conflict of interest: none declared.

Reviewer information

Interactive CardioVascular and Thoracic Surgery thanks Gonzalo Varela, Luca Voltolini and the other, anonymous reviewer(s) for their contribution to the peer review process of this article.