Vocal cord paralysis following carotid endarterectomy: the paradox of return of function

[Advantages of minimally invasive approach for carotid endarterectomy]

OBJECTIVE

To identify the advantages and disadvantages of different approaches for carotid endarterectomy (conventional, longitudinal and transverse incision).

MATERIAL AND METHODS

There were 58 patients who underwent carotid endarterectomy. Patients were divided into 2 groups depending on surgical approach. Group 1 (n=37) - minimal skin incision (less than 5 cm). There were subgroup 1A (transverse minimal skin incision along the natural skin wrinkle, n=17) and subgroup 1B (longitudinal minimal skin incision, n=20). Group 2 (n=21) - conventional longitudinal incision. Surgical outcomes were analyzed after 1 month and 1 year. End-points were mortality, stroke, TIA, cranial nerve neuropathy. Cosmetic effect was evaluated using POSAS scale (Patient and Observer Scar Assessment Scale, Draaijers, 2004).

RESULTS

Mortality, stroke and TIA were absent after 1 month. Cranial nerve neuropathy was not observed in subgroup 1A and diagnosed in 2 (10%) patients of subgroup 1B and 6 (28.5%) patients of group 2. Cosmetic effect: subgroup 1A - 48.4±9.5 scores, subgroup 1B - 52.4±9.2, group 2 - 63.1±11.1 (p<0.05). The outcomes after 12 months: mortality was absent in subgroups 1A and 1B, 2 patients died in group 2 from AMI. Stroke was absent in subgroups 1A and 1B, group 2 - 1 patient. Cranial nerve neuropathy was absent in 1A and 1B subgroups and diagnosed in 4 (21%) patients of group 2. Cosmetic effect: subgroup 1A - 37.2 scores, subgroup 1B - 40.0 scores, group 2 - 55.1 scores. Physical component of QOL: subgroup 1A - 51.63±6.31 scores, subgroup 1B - 46.01±7.53 scores, group 2 - 38.85±5.33 scores. Psychological component of QOL: subgroup 1A - 49.64±6.72 scores, subgroup 1B - 45.68±5.63 scores, group 2 - 48.6±7.36 scores (p<0.05).

CONCLUSION

Transverse minimal skin incision for carotid endarterectomy is a safe alternative to classic longitudinal incision and reduces the risk of postoperative complications with significant cosmetic effect.

Vocal Fold Motion Recovery in Patients With Iatrogenic Unilateral Immobility: Cervical Versus Thoracic Injury

Objectives:

Prognostic information about the return of vocal fold mobility in patients with iatrogenic unilateral vocal fold immobility (UVFI) can help with informed decisions about temporary and permanent treatment options. Although many variables can influence the likelihood of recovery, clinical experience suggests that cervical versus thoracic injury is a determining factor. The purpose of this study was to compare recovery rates from UVFI between cervical and thoracic injuries.

Methods:

A retrospective review of the medical record was performed on all adult patients diagnosed with complete iatrogenic UVFI from 2005 to 2015 (n = 923). Patients with incomplete data and etiologies of idiopathic, malignancy, or stenosis were excluded, leaving a study cohort of 502 patients who were categorized as having UVFI after cervical (n = 329) or thoracic (n = 173) injury. Data regarding site of iatrogenic injury (cervical vs thoracic), mobility status, and time interval to recovery or surgical intervention were recorded and compared using χ2 analyses.

Results:

Overall, 15% of patients recovered vocal fold mobility at a median of 4.1 months. Patients with cervical injury (65 of 329 [20%]) were significantly more likely to recover mobility than patients with thoracic injury (11 of 173 [6.4%]) (odds ratio, 3.63). The cervical cohort contained more women (68% vs 31%) and was younger (mean age, 60.4 ± 13.8 vs 64.1 ± 16.1 years; Cohen’s D = 0.25).

Conclusions:

Patients with cervical injuries resulting in UVFI are 4 times more likely to recover mobility than patients with thoracic injuries. This information can be valuable in counseling patients with UVFI and may affect clinical decision making.

Differences in the microstructure and biomechanical properties of the recurrent laryngeal nerve as a function of age and location

Idiopathic onset of unilateral vocal fold paralysis (UVP) is caused by damage to the recurrent laryngeal nerve (RLN) and results in difficulty speaking, breathing, and swallowing. This damage may occur in this nerve as it loops around the aortic arch, which is in a dynamic biomechanical environment. The goal of this study is to determine if the location-dependent biomechanical and microstructural properties of the RLN are different in piglets versus adolescent pigs. The neck/distal and thoracic/proximal (near the aortic arch) regions of the RLN from eight adolescent pigs and six piglets were isolated and mechanically assessed in uni-axial tension. Two-photon imaging (second harmonic) data were collected at 5%, 10%, and 15% strain during the mechanical test. The tangential modulus (TM) and the strain energy density (W) were determined at each level of strain. The mean mode of the preferred fiber angle and the full width at half maximum (FWHM, a measure of fiber splay) were calculated from the imaging data. We found significantly larger values of TM, W, and FWHM in the proximal segments of the left RLN when compared to the distal segments (18.51 MPa ± 1.22 versus 10.78 MPa ± 1.22, p < 0.001 for TM, 0.046 MPa ± 0.01 versus 0.026 MPa ± 0.01, p < 0.003 for W, 15.52 deg ± 1.00 versus 12.98 deg ± 1.00, p < 0.001 for FWHM). TM and W were larger in the left segments than the right (15.32 MPa ± 1.20 versus 11.80 MPa ± 1.20, p < 0.002 for TM, 0.038 MPa ± 0.01 versus 0.028 MPa ± 0.01, p < 0.0001 for W). W was larger in piglets when compared to adolescent pigs (0.042 MPa ± 0.01 versus 0.025 MPa ± 0.01, p < 0.04). The proximal region of the left porcine RLN is more stiff than the distal region and has a higher degree of fiber splay. The left RLN of the adolescent pigs also displayed a higher degree of strain stiffening than the right. These differences may develop as a result of the more dynamic environment the left RLN is in as it loops around the aortic arch.

Treatment strategy for bilateral carotid stenosis: 2 cases of carotid endarterectomy for the symptomatic side followed by carotid stenting

Since the introduction of carotid stenting (CAS), a combined treatment for bilateral lesions using carotid endarterectomy (CEA) and CAS has been developed. However, there has been only 1 report about CEA then CAS. Herein we describe 2 patients with bilateral severe carotid stenosis who were treated by CEA for the symptomatic side and CAS for the contralateral asymptomatic side. A 71-year-old man underwent CEA for the symptomatic side. Although the patient suffered hyperperfusion syndrome after CEA, he recovered fully after 3 weeks of rehabilitation. Two months later, CAS was performed for the asymptomatic side, and he was discharged with no deficit. A 67-year-old man underwent CEA for the symptomatic side. The patient developed no postoperative neurologic deficits except for hoarseness. Four weeks later, CAS was performed for the contralateral asymptomatic side. After the procedure, however, severe hypotension occurred, and treatment by continuous injection of catecholamine was necessary to maintain systematic blood pressure. The patient was ultimately discharged with no deficit. The combined therapy of CAS for the asymptomatic side and then CEA for the symptomatic side has been recommended by several authors. However, one of the problems of this strategy is the higher incidence of postprocedural hemodynamic complications, and hypotension after CAS may be dangerous for the symptomatic hemisphere. We suggest a combined therapy using CEA for the symptomatic side and then CAS for the asymptomatic side can be 1 beneficial treatment option for patients with bilateral carotid stenosis without coronary artery disease.

Clinical Practice Guideline

Objective

Thyroidectomy may be performed for clinical indications that include malignancy, benign nodules or cysts, suspicious findings on fine needle aspiration biopsy, dysphagia from cervical esophageal compression, or dyspnea from airway compression. About 1 in 10 patients experience temporary laryngeal nerve injury after surgery, with longer lasting voice problems in up to 1 in 25. Reduced quality of life after thyroid surgery is multifactorial and may include the need for lifelong medication, thyroid suppression, radioactive scanning/treatment, temporary and permanent hypoparathyroidism, temporary or permanent dysphonia postoperatively, and dysphagia. This clinical practice guideline provides evidence-based recommendations for management of the patient’s voice when undergoing thyroid surgery during the preoperative, intraoperative, and postoperative period.

Purpose

The purpose of this guideline is to optimize voice outcomes for adult patients aged 18 years or older after thyroid surgery. The target audience is any clinician involved in managing such patients, which includes but may not be limited to otolaryngologists, general surgeons, endocrinologists, internists, speech-language pathologists, family physicians and other primary care providers, anesthesiologists, nurses, and others who manage patients with thyroid/voice issues. The guideline applies to any setting in which clinicians may interact with patients before, during, or after thyroid surgery. Children under age 18 years are specifically excluded from the target population; however, the panel understands that many of the findings may be applicable to this population. Also excluded are patients undergoing concurrent laryngectomy. Although this guideline is limited to thyroidectomy, some of the recommendations may extrapolate to parathyroidectomy as well.

Results

The guideline development group made a strong recommendation that the surgeon should identify the recurrent laryngeal nerve(s) during thyroid surgery. The group made recommendations that the clinician or surgeon should (1) document assessment of the patient’s voice once a decision has been made to proceed with thyroid surgery; (2) examine vocal fold mobility, or refer the patient to a clinician who can examine vocal fold mobility, if the patient’s voice is impaired and a decision has been made to proceed with thyroid surgery; (3) examine vocal fold mobility, or refer the patient to a clinician who can examine vocal fold mobility, once a decision has been made to proceed with thyroid surgery if the patient’s voice is normal and the patient has (a) thyroid cancer with suspected extrathyroidal extension, or (b) prior neck surgery that increases the risk of laryngeal nerve injury (carotid endarterectomy, anterior approach to the cervical spine, cervical esophagectomy, and prior thyroid or parathyroid surgery), or (c) both; (4) educate the patient about the potential impact of thyroid surgery on voice once a decision has been made to proceed with thyroid surgery; (5) inform the anesthesiologist of the results of abnormal preoperative laryngeal assessment in patients who have had laryngoscopy prior to thyroid surgery; (6) take steps to preserve the external branch of the surperior laryngeal nerve(s) when performing thyroid surgery; (7) document whether there has been a change in voice between 2 weeks and 2 months following thyroid surgery; (8) examine vocal fold mobility or refer the patient for examination of vocal fold mobility in patients with a change in voice following thyroid surgery; (9) refer a patient to an otolaryngologist when abnormal vocal fold mobility is identified after thyroid surgery; (10) counsel patients with voice change or abnormal vocal fold mobility after thyroid surgery on options for voice rehabilitation. The group made an option that the surgeon or his or her designee may monitor laryngeal electromyography during thyroid surgery. The group made no recommendation regarding the impact of a single intraoperative dose of intravenous corticosteroid on voice outcomes in patients undergoing thyroid surgery.

Biomechanical properties of recurrent laryngeal nerve in the piglet

Unilateral vocal fold paralysis (UVP) results from damage to the recurrent laryngeal nerve (RLN). The most common causes of UVP are associated with compromised RLN tissue. The purpose of this research was to investigate the biomechanical properties of piglet RLN and identify differences in these properties along its length and in between the left and right side. Quasi-static uniaxial tensile testing and isotropic constitutive modeling was performed on seven piglet RLNs. Stiffness and other biomechanical parameters were derived from these tests and compared from conducting two different statistical analysis for the between and within nerve comparisons. Results showed higher stiffness values in the left RLN segment than for the right. Descriptive data demonstrated a higher stiffness in RLN segments surrounding the aortic arch, indicating a more protective role of the extracellular matrix in these nerves. This research offers insight regarding the protective function of the RLN connective tissues and structural compromise due to its environment.

Acute respiratory failure after deep cervical plexus block for carotid endarterectomy as a result of bilateral recurrent laryngeal nerve paralysis

We report about a case of acute respiratory distress (73-year-old female), which occurred minutes after a deep cervical plexus block (40 ml ropivacaine 0.5%) for carotid endarterectomy (CEA) and required immediate endotracheal intubation of the patient's trachea and consecutive mechanical ventilation. Subsequently, CEA was performed under general anaesthesia (TIVA) with continuous monitoring by somatosensory-evoked potentials. After a period of 14 hours, the endotracheal tube could be removed, the patient being in fair respiratory, cardiocirculatory and neurological conditions. Retrospectively, acute respiratory distress was caused by a combination of ipsilateral plexus blockade-induced and pre-existing asymptomatic contralateral recurrent laryngeal nerve (RLN) paralysis confirmed by a postoperative ENT-check and related to previous thyroid surgery more than 50 years ago. RLN paralysis, often being asymptomatic, represents a typical complication of thyroid and other neck surgery with reported incidences of 0.5-3%. Therefore, a thorough preoperative airway check is advisable in all patients scheduled for a cervical plexus block. Particularly in cases with a history of respiratory disorders or previous neck surgery a vocal cord examination is recommended, and the use of a superficial cervical plexus block may lower the risk of respiratory complications. This may prevent a possibly life-threatening coincidence of ipsilateral plexus blockade-induced and pre-existing asymptomatic contralateral RLN paralysis.

Recurrent laryngeal nerve paralysis: anatomy and etiology

Etiologies of adult vocal paralysis are varied by the site of the lesion as well as the extent and cause of the damage. Most large series point to surgery and neoplastic causes for recurrent nerve paralysis. A detailed history is important when working up a patient with this voice disorder. Knowledge of the anatomy of the head, neck, and chest as well as the mechanisms behind vocal fold paralysis is essential in the evaluation and treatment of recurrent nerve paralysis. Many of the surgical and traumatic causes of hoarseness are from compression type injuries. Recovery is dependent on the type, extent, and site of nerve lesion. Familiarity with this data allows the otolaryngologist to tailor management to suit each patient with vocal fold paralysis.

Left-Side Preference in Carotid Endarterectomies

Although the incidence of carotid atheromatous disease is presumably equal between the right and left carotid arteries, right and left carotid endarterectomies (CEs) may not be performed with equal frequency on the two sides. This study sought to examine whether right and left CEs are performed with equal frequency and whether there are any differences in outcome between these groups. Detailed chart review was performed on all CEs performed from 1979 through 1998 at our institution, and those lacking side data were excluded. Data were collected on the side of the procedure, demographics, comorbid conditions, details of the procedure, hospital stay, and major complications. The surgeons performing CE were surveyed about their practice of considering side factors. CE was performed on the left in 1190 (52%) of 2305 procedures; 1115 (48%) of the procedures were right CEs. This difference is statistically significant ( P = 0.014). No significant differences in demographics, comorbidity, presence of symptoms before surgery, length of stay, or postoperative morbidity or mortality between the left and right groups were found. A majority of the surgeons surveyed indicated they do consider the relationship of side of the carotid disease to the patient's dominant side. The significant difference in the performance of left CE more often than right has not been previously reported. This may reflect willingness by surgeons to intervene more frequently in carotid disease on the side supplying the dominant hemisphere. A prospective CE outcome study that identifies the side of CE and the patient's dominant side is needed for further exploration of this issue.

Vocal fold paralysis following carotid endarterectomy

Injury to the vagus nerve or one of its branches during carotid endarterectomy (CEA) can result in vocal fold paralysis (VFP). This study assessed prospectively 73 patients undergoing CEA. A total of 76 procedures were performed in these patients over a one-year period. All patients underwent pre-operative and post-operative assessment of vocal fold mobility by indirect laryngoscopy and/or flexible nasendoscopy. All patients had normal vocal fold mobility pre-operatively. Eight patients (10 per cent) complained of hoarseness after surgery and in three patients (four per cent) examination confirmed an ipsilateral VFP. This persists in all three patients at six-month follow-up. Vocal fold assessment is important in patients undergoing CEA, particularly when performing second side surgery. We recommend that patients should be informed of the risk of VFP following CEA when obtaining consent.

Changing etiology of vocal fold immobility

HYPOTHESIS

Vocal fold immobility is a sign of underlying disease. When the etiology remains unclear, evaluation may become time consuming and costly, and directed work-up imperative. This study examined the hypothesis that the etiologies of vocal fold immobility are changing, with extralaryngeal malignancies and nonthyroidectomy surgical trauma having become more common causes.

METHODS

A retrospective review of consecutive patients with vocal fold immobility who had an adequate workup to determine the etiology.

RESULTS

Three hundred ninety-seven cases with a determined etiology were identified, yielding 280 unilateral and 117 bilateral immobilities. The largest single category in unilateral immobility was nonlaryngeal malignancy--69 patients (24.7%)--80% of which were pulmonary or mediastinal, followed by 67 patients (23.9%) with immobility secondary to surgical trauma. Thyroidectomy accounted for only 8.2%. The leading cause of bilateral immobility was surgical trauma-30 patients (25.7%)--21 (18%) of whom had thyroidectomy. Acute and chronic intubation injuries accounted for 21 unilateral (7.5%) and 18 bilateral (15.4%) cases.

CONCLUSIONS

These data indicate a changing etiology of vocal fold immobility, with growing percentages of extralaryngeal malignancies and surgery-related injuries. These findings have implications for the timing and method of management based on anticipated outcome.