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J Thorac Cardiovasc Surg 2001;121:642-648
© 2001 The American Association for Thoracic Surgery
General Thoracic Surgery |
From the Departments of Otolaryngology and Head and Neck Surgery,a General and Thoracic Surgery,b Anesthesia,c and Radiology,d University Hospital Center, University of Auvergne, Clermont-Ferrand, France.
Received for publication July 12, 2000. Revisions requested Aug 29, 2000; revisions received Sept 14, 2000. Accepted for publication Oct 25, 2000. Address for reprints: Thierry Mom, MD, PhD, Service d'ORL et de Chirurgie Cervico-Faciale, Centre Hospitalier Universitaire, 30 place Henri Dunant, 63 000 Clermont-Ferrand, France (E-mail: tmom{at}chu-clermontferrand.fr).
Abstract
Objectives: We sought to prevent postoperative swallowing disorder, aspiration, and sputum retention in cases of recurrent laryngeal or vagus nerve section occuring during lung cancer resection.
Methods: In 14 of 25 consecutive patients, type I thyroplasty and thoracic operations were performed during the same period of anesthesia. All patients had a preoperative laryngeal computed tomographic scan providing us with indispensable measurements for vocal fold medialization under general anesthesia (ie, without intraoperative phonatory control). Nine remaining patients had a type I thyroplasty delayed from thoracic operations because of intraoperative doubt about laryngeal innervation injury, and 2 did not need a laryngeal operation. Main postoperative records consisted of swallowing ability, respiratory complications, and quality of voice.
Results: No swallowing disorder, aspiration, or sputum retention occurred in cases of concomitant laryngeal and thoracic operations. Of these 14 patients, a single case (7%) of major complication (vocal fold overmedialization) occurred and required an early and successful revision thyroplasty; one case of cervical hematoma that did not require surgical drainage was considered a minor complication (7%). Twelve (86%) patients who underwent the concomitant association of both operations were fully satisfied with their quality of voice.
Conclusions: Type I thyroplasty and thoracic operation can be advantageously associated in case of injury to laryngeal motor innervation to prevent postoperative swallowing disability and dramatic respiratory complications.
The surgical treatment of lung carcinoma most often consists of tumor resection associated with mediastinal lymph node dissection. Because of their anatomic location, the left vagus nerve (VN) and recurrent laryngeal nerve (RLN) are exposed to cancer invasion and to surgical injury. From our own experience, we have learned that surgical severing of these nerves results in vocal cord abduction in most cases, whereas mild injury to these nerves is more likely to result in a paralyzed vocal cord in the intermediate position (unpublished data). This impaired laryngeal mobility can be dramatic after lung resection because of postoperative respiratory complications caused by a glottic gap. Swallowing disorder is a major consequence of such a glottic incompetence
1-4 and can be life-threatening in patients just operated on for lung cancer. 1,5 Also frequent, in cases of laryngeal paralysis, is an ineffective cough that increases the risk of pulmonary infections. 6 To quickly restore glottic competence, one can choose between 2 types of procedures: intrafold injection or a medialization operation. Currently, for numerous teams, laryngeal framework operations for vocal fold medialization, such as type I thyroplasty, are considered better techniques than intrafold injection for laryngeal rehabilitation. 7-9 Whatever the type of laryngeal procedure chosen, early glottal rehabilitation has to be rapidly achieved to prevent serious pulmonary complications in such patients. It would be even better to avoid or minimize postoperative glottic insufficiency any time the VN or RLN has been severed during thoracic operations. This report shows that type I thyroplasty can be associated with lung cancer resection during the same period of general anesthesia, with success and a low morbidity rate when the laryngeal innervation has been severed during the thoracic surgical procedure.
Patients and methods
Patients
In a preliminary series of patients operated on for lung cancer (unpublished data), we unsurprisingly observed that in cases of VN or RLN section, about 50% of patients had postoperative respiratory complications caused by glottic insufficiency that were sometimes life-threatening. In these cases a type I thyroplasty was achieved, with success within the first postoperative week. Then, in all cases of intraoperatively recognized VN or RLN section that occurred during thoracic operations for lung cancer from November 1998 to February 2000, we performed a type I thyroplasty during the same period of general anesthesia immediately after thoracic wound closure. This association of concomitant type I thyroplasty and lung cancer resection during the same general period of anesthesia is herein referred to as CTLC. Delayed type I thyroplasty performed a few days after the thoracic operation because of intraoperative doubt about VN or RLN injury is herein referred to as DTLC.
Preoperative records
Characteristics of each patient were noted (including historical background) at the first visit to the thoracic surgeon. A preoperative visit to the otolaryngologist aimed at verifying the integrity of the upper aerodigestive tract because lung and head and neck cancers are often associated. 1,10,11 Examination by the otolaryngologist included a fiberoptic visualization of the larynx. All patients were informed they could also be operated on for vocal fold medialization in case of VN or RLN section. A preoperative computed tomographic (CT) scan of the larynx allowed us to obtain the following laryngeal measurements: distance between the left thyroid lamina and the midline; thickness of the left thyroid lamina; and thickness of the left soft tissues of the larynx from the medial border of the vocal fold to the medial border of the left thyroid lamina at the junction of the anterior and middle thirds of the vocal fold(Fig 1). The midline was identified on CT scans acquired during phonation, whereas the thickness of lateral soft tissues of the larynx required an open glottis to be measured. As shown inFig 1, d, the maximal distance that could be covered by vocal fold medialization was measured from the inner side of the thyroid lamina to the midline along the perpendicular line to the thyroid lamina joining it to the junction of the anterior and middle thirds of the vocal fold.
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Surgical procedure
Once the thoracic wound had been closed, the tracheal tube was changed for a smaller one (internal diameter size, 6.5 or 7 mm) to facilitate the vocal fold medialization. The patient was then laid down on his or her back, with the neck extended and the head slightly rotated to the right. The principle of the surgical technique we used was essentially described by Isshiki and associates 12,13 in the English literature. In brief, a lateral cervical approach to the left thyroid lamina was achieved, and a chondral graft was harvested from the superior border of this cartilage. The graft was then thinned out as much as required according to CT scan measurements. A cartilage window was made at the level of the vocal fold by using a 1-mm diamond burr. The cartilage window was not removed but impacted toward the midline so as to medialize the vocal fold. The medialized cartilage was then maintained in place with the help of the chondral graft. The latter was vertically placed over the thyroid window and sandwiched between the thyroid lamina and the impacted thyroid window(Fig 2). Great care was taken to preserve the internal layer of perichondrium. An aspirative drain was placed, and the neck wound was closed in layers. The thickness of the graft that was interposed between the thyroid lamina and the impacted cartilage window was based on the preoperative CT scan measurements, as follows:
G = MaxD – (TL + ST),
where G is defined as the thickness of the graft, MaxD as the maximal medialization allowed, TL as the thickness of the thyroid lamina, and ST as the thickness of the lateral soft tissues of the larynx.
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Voice assessment and swallowing ability
Patients were asked to score the quality of their voice after thyroplasty as follows: 1, poor voice; 2, acceptable voice; or 3, completely satisfying voice. Patients who were not able to drink mineral water without aspiration were considered to have a swallowing disorder. These 2 criteria were assessed at postoperative day 1, after 1 postoperative month, and 6 and 12 months after the surgical procedure whenever possible.
Postoperative vocal fold position
The vocal fold position as visualized through nasofibroscopic examination was quoted as excessive (overmedialization), perfect (medial position), acceptable (paramedian), or poor (failure of correction). This fiberoptic laryngeal examination was performed as early as the first postoperative day, unless the patient needed prolonged mechanical ventilation in the intensive care unit. In addition, CT scan measurement of the glottic gap during phonation was achieved after 1 postoperative month, whenever possible, at the middle third of the vocal fold.
Postoperative complications
Postoperative complications were all listed with special attention to those caused by swallowing disability. Respiratory complications considered as consequences of swallowing disorder included pneumonia and postoperative bronchoscopy for major sputum production.
The length of hospitalization was defined as the number of postoperative days actually spent in our institution, including the stay in intensive care unit.
Data analysis
Characteristics and history of patients before the thoracic surgical procedure, hospitalization duration, postoperative swallowing ability and quality of voice, postoperative respiratory complications, global morbidity, and morbidity specifically related to the additional laryngeal operations in the case of patients undergoing CTLC were noted. Quantitative results were expressed as means of raw data ± SD. Data collection was done before the surgical procedure, as soon as after detubation (ie, usually the day of surgery), and after the first, sixth, and twelfth postoperative months.
Results
From November 1998 to February 2000, 71 patients were operated on for left lung cancer in our institution. Twenty-three (32%) underwent a surgical left vocal fold medialization; they were 19 men and 4 women (mean age, 62 ± 8 years). Fourteen (10 men and 4 women) underwent a CTLC. Eleven patients did not undergo CTLC but only left lung resection because the VN or RLN section was not intraoperatively certain. Nine of them needed a delayed type I thyroplasty (DTLC), and 2 did not because they remained able to swallow and clear their bronchial secretions despite laryngeal impairment. Mean follow-up for the whole series of type I thyroplasty cases was 9.8 ± 5 months.Table I indicates the cancer characteristics of each patient, the type of nerve impairment, and the time when the laryngeal operation was performed. The mean length of the laryngeal framework operation was 51 ± 9 minutes (range, 40-70 minutes).Table II shows the length of total hospitalization and intensive care unit stay. Three patient died before the end of hospitalization. Death occurred in 2 patients undergoing CTLC (cardiogenic pulmonary edema in both cases) and in 1 patient undergoing DTLC (sudden death without respiratory distress). No death could be directly imputed to thyroplasty.
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Thyroplasty in patients undergoing DTLC was carried out under local anesthesia in only 4 patients because the other such patients were usually exhausted and too dyspneic to undergo a laryngeal operation under local anesthesia for about 1 hour. No complication directly related to thyroplasty occurred in cases of DTLC.
Effects of thyroplasty
Postoperative voice and swallowing ability
Type I thyroplasty gave a 100% success rate on swallowing ability. This was our main goal, especially in patients undergoing CTLC. This good result on deglutition was maintained up to the first postoperative month in all patients and in all patients controlled at the sixth postoperative month (n = 9) and after 1 year (n = 5). The quality of voice was given a score of 3 in all patients undergoing DTLC. Of the 13 patients undergoing CTLC, 11 gave a score of 3 for their vocal quality and 2 gave a score of 2.
Postoperative vocal fold position
Fiberoptic laryngoscopy performed in the early postoperative period was satisfactory and there was no laryngeal dyspnea in all cases but one. In all patients but one, no glottal gap was observed during phonation. It is noteworthy that in the latter patient, swallowing ability was good, with no aspiration. The glottic gap measured on CT scans after 1 postoperative month was, on average, 0.43 ± 0.4 mm in the CTLC group (range, 0-0.94 mm) and 0.26 ± 0.5 mm in the DTLC group (range, 0-0.8 mm), which is a global average of 0.37 ± 0.4 mm for all patients having undergone a thyroplasty. Patient 2, who underwent a delayed type I thyroplasty, is remarkable in that he eventually recovered his vocal fold mobility 1 year later, although he underwent a laryngeal framework operation.
Discussion
The main result of this report is to show that the association of concomitant lung cancer resection and type I thyroplasty is effective in lowering postoperative complications when the VN or RLN are injured. To our knowledge, this association of concomitant lung cancer resection and type I thyroplasty achieved during the same period of general anesthesia had never been reported before. The worst case of complication reported herein was an overmedialization of the vocal fold that was early and easily corrected. We are now more demanding on the quality of preoperative CT scans of the larynx, which must include phonatory pictures. Indeed, because thyroplasty was achieved under general anesthesia in patients undergoing CTLC, it was not possible to intraoperatively test the quality of voice, as is usually done. 12,13 Cervical hematomas were easily prevented by means of high enough vacuum wound drainage. However, we strongly recommend use of effective aspirative drainage because these patients are at risk of laryngeal hematoma.
Thyroplasty duration of about 50 minutes was acceptable in such cases since all patients tolerated this additional operative period. In particular, no increase in thoracic infection was noted. Inherent complications of thyroplasty were as much lowered as possible. Even though most surgical teams prefer to use silicone implants, 12,14,15 some complications caused by the use of silicone have been reported, such as prosthesis extrusion or migration 16,17 or even allergy to the solid silicone implant. 18 We avoided all problems related to foreign body insertion by choosing to medialize the paralyzed vocal fold with chondral autografts not only in patients undergoing CTLC but also in those undergoing DTLC. Type I thyroplasty has already been reported to be reversible, and we can confirm this point. It was possible, at the second postoperative day, to replace the graft in patient 14 without any problems. Additional evidence of minimal invasion of thyroplasty is given by the case of patient 2 (DTLC). In this patient the paralyzed vocal fold completely recovered its mobility 1 year after thyroplasty, although the course of the left vocal fold was shortened by the chondral graft.
The low morbidity rate of CTLC, imputable to laryngeal framework operations, is satisfactory, inasmuch as postoperative swallowing disorders and sputum retention could be avoided in all cases despite the vocal fold immobility. Undoubtedly, swallowing disorders are to be certainly avoided in case of lung operations for cancer because they can be responsible for fatal respiratory complications. 5 In cases in which the vocal fold innervation is severed during lung operations for cancer but no laryngeal operation is performed, we know from our own experience that aspiration can be expected in about one third of patients (unpublished data). In the current series, out of the 11 patients who did not undergo a CTLC but who eventually experienced postoperative laryngeal paralysis, only 2 (18%) did not need a type I thyroplasty. Other teams also have reported high rates of aspiration after alteration of laryngeal mobility, some as high as 53% 19 or 73%. 20 This point in itself justifies the realization of CTLC. The excellent result regarding swallowing ability lasted at least as long as 1 month in all patients. All patients seen after several months (9 at 6 months and 5 at 1 year) had a persistently good swallowing ability. Postoperative laryngeal examination and CT scans show that even though a glottal gap might persist, swallowing disorders were avoided in all cases. It is possible that glottic closure can be obtained because of the Bernouilli effect, even though the vocal fold position is incompletely corrected, provided that the residual glottic gap is not too large (see Isshiki 8): the airflow passing through the glottal gap sucks the vocal fold mucosa to the midline because of the midline negative pressure created by the airflow.
The postoperative quality of voice, as subjectively assessed by the patients themselves, was satisfying in our series. None of our patients were voice professionals, however.
Delayed thyroplasty or other laryngeal procedures let patients incur respiratory complications that can be dramatic before laryngeal rehabilitation is achieved. In another type of patients (ie, those undergoing skull base operations), it has recently been recommended to perform a laryngeal rehabilitation early after injury to the VN, as soon as postoperative day 2, to lower the postoperative complication rate. 21 It is of even greater interest to be able to prevent such complications whenever possible. Coupling type I thyroplasty and lung cancer resection, whenever injury to the RLN or VN is recognized, meets this goal and results in an acceptable morbidity rate.
Finally, because CTLC can be a safe procedure in the vast majority of patients and prevents postoperative respiratory complications caused by laryngeal dysfunction, we do recommend it in cases of RLN or VN section.
Acknowledgments
We thank Professor Bernard Guerrier, who taught us most of our knowledge in laryngeal surgery.
References
This article has been cited by other articles:
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  C. Doddoli, A. Aragon, F. Barlesi, B. Chetaille, S. Robitail, R. Giudicelli, P. Fuentes, and P. Thomas Does the extent of lymph node dissection influence outcome in patients with stage I non-small-cell lung cancer? Eur. J. Cardiothorac. Surg., April 1, 2005; 27(4): 680 - 685. [Abstract] [Full Text] [PDF]
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A. L. Hamdan, R. V. Moukarbel, F. Farhat, and M. Obeid Vocal cord paralysis after open-heart surgery Eur. J. Cardiothorac. Surg., April 1, 2002; 21(4): 671 - 674. [Abstract] [Full Text] [PDF]
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