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Successful immediate phrenic nerve reconstruction during mediastinal tumor resection

2001; Elsevier BV; Volume: 122; Issue: 6 Linguagem: Inglês

10.1067/mtc.2001.117274

1097-685X

T Schoeller, Markus Öhlbauer, Gottfried Wechselberger, Hildegunde Piza‐Katzer, R Margreiter,

Tracheal and airway disorders

Unilateral phrenic nerve paralysis is a common lesion in cardiothoracic surgery that usually results in minimal morbidity but may be symptomatic in patients with borderline lung function.1Tripp HF Bolton JW. Phrenic nerve injury following cardiac surgery: a review.J Card Surg. 1998; 13: 218-223Crossref PubMed Scopus (72) Google Scholar, 2de Leeuw M Williams JM Freedom RM Williams WG Shemie SD McCrindle BW. Impact of diaphragmatic paralysis after cardiothoracic surgery in children.J Thorac Cardiovasc Surg. 1999; 118: 510-517Abstract Full Text Full Text PDF PubMed Scopus (86) Google Scholar In such symptomatic cases plication of the paralyzed hemidiaphragm has been previously suggested to alleviate dyspnea by reducing paradoxic movement of the paralyzed hemidiaphragm.3Graham DR Kaplan D Evans CC Hind CR Donnelly RJ. Diaphragmatic plication for unilateral diaphragmatic paralysis: a 10-year experience.Ann Thorac Surg. 1990; 49: 248-251Abstract Full Text PDF PubMed Scopus (83) Google Scholar We believed, however, that optimal treatment of diaphragmatic dysfunction caused by tumor infiltration of the phrenic nerve might be immediate microsurgical phrenic nerve reconstruction after curative resection of the tumor. To our knowledge, this strategy and its feasibility have not been described previously. We here report on our initial experience with this concept. A 75-year-old woman with a 2-month history of recurrent dyspnea during exercise was referred for diagnostic workup. A chest radiograph demonstrated paralysis of the left hemidiaphragm (Figure 1), most likely caused by a tumor in the anterior mediastinum with infiltration of the left phrenic nerve, as shown by computed tomographic scan (Figure 2).Fig. 2Preoperative computed tomographic scan showing the tumor ventral from the aorta with infiltration of the phrenic nerve.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Through a median sternotomy the tumor was identified and resected en bloc with parts of the affected pericardium, pleura, lung parenchyma, and a patch of the ascending aorta. As was suspected, the left phrenic nerve was infiltrated by the tumor. A 5-cm long piece had to be resected starting 8 cm from the diaphragm, leaving a 3-cm long distal stump. Because the patient's early signs of dyspnea were more likely caused by phrenic nerve paralysis than by direct tumor compression, immediate phrenic nerve reconstruction with a sural nerve graft from the right calf was considered. End-to-end nerve coaptation was performed with an epineural microsurgical 8-0 Ethilon interrupted suture (Ethicon, Inc, Somerville, NJ) at both graft ends. The nerve suture was secured with 0.5 mL of topically applied fibrin glue. The sural nerve graft was taken 3 cm longer than the original phrenic nerve defect to allow extracardiac excursions after partial pericardial resection (Figure 3).Because the patient was already weaned from cardiopulmonary bypass and the beating heart thus did not allow the use of a microscope, reconstruction was performed with magnifying loupes. Histologic and immunohistochemical examination revealed a malignant thymoma (World Health Organization type C) with clear resection margins. The postoperative course was uneventful. At 3 months the patient had completely recovered from the operation and, although in excellent physical condition, still had dyspnea. The chest x-ray film still showed an elevated left hemidiaphragm. In contrast, 9 months after reconstruction, the chest radiograph demonstrated both hemidiaphragms at the same level as a sign of successful axonal regeneration of the formerly paralyzed phrenic nerve (Figure 4).Fluoroscopy demonstrated adequate and symmetric motion of both hemidiaphragms. At that time lung function had improved to allow the patient to resume former athletic activities. Comparative surface measurement of nerve conduction velocity on both sides and surface stimulation of the reconstructed phrenic nerve proved that diaphragmatic reinnervation through the nerve graft had been successful. At the donor site the patient noticed a small numb area at the dorsum of the foot without major discomfort. The consequences of phrenic nerve injury are variable and depend to a large extent on the individual patient's condition, particularly pulmonary function and age. Pathologic conditions may range from an asymptomatic radiographic abnormality (the phrenic nerve can even be harvested with negligible morbidity as a source for brachial plexus reconstruction in otherwise healthy patients)4Gu YD Ma MK. Use of the phrenic nerve for brachial plexus reconstruction.Clin Orthop. 1996; 323: 119-121Crossref PubMed Scopus (109) Google Scholar to severe pulmonary dysfunction and even mortality in patients with primarily reduced lung function. According to the literature, diaphragmatic plication appears to be the most effective option for patients severely compromised by phrenic nerve injury. The case presented here demonstrates that irreversible symptomatic hemidiaphragmatic paralysis can be efficiently treated by direct reconstruction with a nerve graft, which is probably less invasive than plication of the diaphragm. This method, however, is recommended only for cases of short-lasting paralysis, because irreversible denervation of a muscle occurs within 1 year after onset of paralysis through motor endplate disintegration. We therefore suggest immediate microsurgical phrenic nerve repair whenever a phrenic nerve lesion is diagnosed either in the context of resection or operative complication under the following conditions: (1) An adequate time frame must be provided to allow complete reinnervation considering that a nerve regenerates at a velocity of 1 mm per day from the proximal nerve coaptation site to the motor endplate in the diaphragm; (2) thoracotomy is performed for other reasons; (3) the patient's general condition must allow an extra operating time of at least 30 minutes for reconstruction without increasing the risk. This report proves—to our knowledge for the first time—the feasibility of immediate phrenic nerve reconstruction after resection of a malignant tumor. It further shows that the technique of microsurgical repair with sural nerve transfer can be applied safely in phrenic nerve injury with nearly negligible donor-site morbidity.5Ehretsman RL Novak CB Mackinnon SE. Subjective recovery of nerve graft donor site.Ann Plast Surg. 1999; 43: 606-612Crossref PubMed Scopus (39) Google Scholar We believe that in selected cases a nerve graft is an excellent means of reanimating the diaphragm and thus completely restoring the patient's ventilation.