by Brian Camazine, M.D.
INTRODUCTION
Iatrogenic injury to the recurrent laryngeal nerve usually occurs during thyroid surgery but can also occur during surgery in the region of the carotid artery. These injuries can cause significant morbidity including hoarseness, recurrent aspiration and pneumonia. Meticulous meticulous surgical technique combined with detailed knowledge of surgical anatomy can help avoid this complication.
CASE PRESENTATION
A 42 year old female with an enlarged left anterior cervical lymph node was referred to a surgeon for biopsy. The node had been present for one month and had decreased in size from 3 cm to 1.5 cm with antibiotic treatment. On physical examination the node was described as “barely palpable”. At surgery, a 4 cm incision was made in the left upper neck approximately 2.5 cm below the angle of the jaw. The surgeon “...explored down to the carotid sheath...[and] “...anterior and posterior to the sternocleidomastoid muscle” but was unable to locate the node. Two weeks after surgery, the patient saw her surgeon and complained of shortness of breath and weakness of her voice. Laryngoscopy examination showed paralysis of the left vocal cord.
The patient was a receptionist and was unable to return to work because of the weakness of her voice. She filed suit against the surgeon and was ultimately awarded $250,000.
DISCUSSION
“Enlarged and generally asymptomatic lymph nodes, most frequently involving the head, neck and inguinal areas, are relatively common clinical findings. Their persistence for a prolonged period of time requires further investigation”(1). “The extent of workup in patients with cervical adenopathy has always been controversial. Extensive workup in the absence of a histologic diagnosis indicative of a malignant process is unwarranted. Although open biopsy may be necessary for certain benign conditions, its routine application for metastatic nodes is not advised“(2). Fine needle aspiration cytology is a noninvasive procedure that is highly effective in diagnosing malignant, as well as benign, lymphadenopathy. In expert hands, adequate specimens are obtained in greater than 95% of specimens and diagnostic accuracy is greater than 95%, Most experts agree that fine needle aspiration, not open biopsy, should be the initial diagnostic procedure when evaluating cervical lymphadenopathy (see Fig.1). Fine needle aspiration is accurate, safe, inexpensive, and avoids the potential morbidity of an open biopsy. (1,2,3,4,5).
Open biopsy and neck explorations, especially in the region of the carotid sheath, can result in significant morbidity, especially if the goal of the surgery is a search for enlarged lymph nodes. After neck exploration for carotid endarterectomy, for example, the incidence of cranial nerve injury reported in the literature ranges from 3% to 23% (6). Injury to these nerves is usually “...caused by retraction, stretching, or clamping of the nerve; the transection of a particular cranial nerve should be exceptional, providing the surgeon possesses in-depth knowledge of normal and anomalous cranial nerve anatomy”. From a medicolegal point of view, cranial and cervical nerve injuries can be classified as “major” and “minor” according to their clinical consequences. “...severe and evident functional changes can result from injury to the so-called major nerves [including]...the vagus nerve and its accompanying recurrent laryngeal nerve”(7).
“Vagal nerve injuries have been well documented in the medical literature. The vagus nerve and its branches can be damaged as a result of direct injury to the vagal trunk during dissection, retraction or clamping. The recurrent laryngeal nerve can also be damaged by retraction, because it lies within the tracheoesophageal groove. These injuries can be the most devastating to the patient. Clinical manifestations range from mild symptoms of hoarseness and loss of effective cough mechanism, to upper pharyngeal dysphagia with aspiration, to life-threatening airway obstruction from bilateral recurrent laryngeal nerve injury. Injuries can involve the recurrent laryngeal nerve [or]...the vagal trunk”(8).
“The vagus nerve exits the skull by way of the jugular foramen...It then descends vertically into the neck in the carotid sheath posterolateral to the carotid artery and jugular vein. Occasionally the vagus can be anteromedial to the carotid artery, a location that increases its risk of injury. The vagus nerve can be intimately associated with the internal carotid artery and common carotid artery in the carotid sheath. Great care must be used during dissection of these arteries to avoid inadvertent vagal injury”(6)(see Fig.2).
“The recurrent laryngeal nerve loops around the subclavian artery on the right and the aortic arch on the left. The nerve then ascends into the neck in the tracheoesphageal groove. This nerve supplies motor innervation to all intrinsic muscles of the larynx except the cricothyroid muscle. It also supplies sensory innervation to the laryngeal mucosa below the true vocal cord... Self-retaining retractors that are too deep, exerting pressure on the trachea and tracheoesophageal groove, can result in direct recurrent laryngeal nerve injury. Although unusual, a nonrecurrent laryngeal nerve can occur. This nerve leaves the vagus around the level of the carotid bifurcation and courses medially and posterior to the common carotid artery to enter the larynx directly. [A non-recurrent] nerve is at risk during dissection of the common carotid artery and carotid bifurcation...”(see Fig.2). Dehn and Taylor believe that recurrent laryngeal nerve dysfunction is [often] the result of vagal trunk injury”(6).
CONCLUSION
Fine needle aspiration cytology should be the initial procedure in investigating cervical lymphadenopathy. If open biopsy is necessary then it should be performed by well trained surgeons under optimal conditions. Injury to cranial nerves, especially the vagus and its branches, should be avoidable providing the surgeon uses meticulous surgical technique combined with detailed knowledge of surgical anatomy.
REFERENCES
1. Cytologic diagnosis of reactive lymphadenopathy in fine needle aspiration biopsy specimens. Stani J. Acta Cytol 1987 Jan-Feb;31(1):8-13.
2. Fine-needle aspiration in the diagnosis of cervical lymphadenopathy. Shaha A, Webber C, Marti J. Am J Surg 1986 Oct;152(4):420-
3. Fine needle aspiration cytology as a preliminary diagnostic procedure for asymptomatic cervical lymphadenopathy. Sarda AK, Bal S, Singh MK, Kapur MM. J Assoc Physicians India 1990 Mar;38(3):203-5.
4. Fine needle aspiration cytology in the evaluation of head and neck masses. Schwarz R, Chan NH, MacFarlane JK. Am J Surg 1990 May;159(5):482-5.
5. Iatrogenic spinal accessory nerve injury. London J, London NJ. Ann R Coll Surg Engl 1996 Mar;78(2):146-50.
6. Cranial/cervical nerve dysfunction after carotid endarterectomy. Schauber MD, Fontenelle LJ, Solomon JW, Hanson TL. J Vasc Surg 1997 Mar;25(3):481-7.
7. Cranial and cervical nerve injuries after carotid endarterectomy: a prospective study. Ballotta E, Da Giau G, Renon L, Narne S, Saladini M, Abbruzzese E Meneghetti G. Surgery 1999 Jan;125(1):85-91.
8. Cranial and cervical nerve injuries after repeat carotid endarterectomy. AbuRahma AF, Choueiri MA J Vasc Surg 2000 Oct;32(4):649-54.
About Brian Camazine, MD |
