HSC Section 6 Nov2016 Green Book

Paddle et al

Table 4. Yield of CT in IUVFP.

Yield

Positive CT, n

Yield, % (95% CI)

Needed to Treat/Harm, n

5 a

2.9 (0.94-6.6) 27.6 (21.1-34.9)

34

Diagnostic Incidental

48 b

4

Abbreviations: CI, confidence interval; CT, computed tomography; IUVFP, idiopathic unilateral vocal fold paresis. a Diagnostic of benign lesion, n = 4; diagnostic of a malignancy, n = 1. b Underwent clinical or imaging follow-up alone, n = 40; underwent fine-needle aspiration alone, n = 5; required operation, n = 3.

Table 5. Proportion of Incidental Lesions by Anatomic Group.

Incidental Lesion Type

Proportion of All Incidental Lesions

Thyroid abnormalities : nodules, cysts, enlargement

29 40 15 13

Pulmonary lesions : nodules, granulomas, pleural plaques, hilar lymphadenopathy Mediastinal lesions : thoracic aortic aneurysms, mediastinal lymphadenopathy Cervical abnormalities : laryngocele, thyroglossal duct cyst, cervical lymphadenopathy

Miscellaneous : vertebral lesions

4

Table 6. Etiology of Vocal Fold Paralysis vs Paresis (in Percentages).

Paralysis

Paresis

MacGregor 10 (n = 1308)

Koufman 4 (n = 50)

Heman-Ackah 1 (n = 46)

Badia 12 (n = 176)

Present Study (n = 237)

Etiology

Total iatrogenic

22

20

4.3

39.2

3.4 2.9 5.7

Total neoplastic lesions

21.7 39.9 16.4

6 6

13

1.1

Total nonneoplastic benign disease

54.3 28.3

13.6

Idiopathic a

68

46

88

a Includes viral neuritis.

Discussion

perspective, when one considers that 4 of 5 (80%) of our CT- positive cases had a pathology that required operation, which untreated may have led to serious morbidity. Conversely, the study by Badia et al 12 described a final yield of 0%, as the single CT-positive case was benign and required no intervention. The argument against the routine use of CT in the eva- luation of IUVFP is strengthened when one considers the discovery of incidental lesions and the potential morbidities due to the performance of additional diagnostic tests and interventions. This study identified an incidental yield of 27.6%. The majority of these patients with incidental ima- ging findings (83.3%) underwent serial examination and imaging alone (including serial thyroid ultrasound, CT of the neck and chest, and magnetic resonance imaging of the brain), thus exposing them to additional perhaps unneces- sary radiation and expense. In all of these imaging-alone cases, the incidental lesions did not evolve into clinically significant pathologies over the mean laryngologic follow- up period of 2.95 years (SD, 1.52). Five patients underwent

The role of CT in the evaluation of vocal fold paralysis is well established. Its near routine use is justified by a high diagnostic yield (35% to 62%) 6,7 and a high proportion of cases due to underlying neoplasia (13% to 33%). 8,10 Its role in paresis, however, is unclear, partly because the preva- lence of a neoplastic etiology in published studies is a com- paratively low (1.1% to 6%; Table 6 ) 1,4,12 and partly because there is a paucity of studies examining the diagnos- tic yield of CT paresis. A previous study found the diagnos- tic yield of CT in IUVFP to be 1.7%. 12 The overall diagnostic yield of CT in the evaluation of paresis in the current study was 2.9% (95% confidence interval, 0.94% to 6.6%). Such values may justify the use of routine CT evaluation. A similar percentage yield (1% to 4%) is seen by many authors as justification for the routine use of magnetic resonance imaging in the evaluation of asym- metric sensorineural hearing loss. 14 This argument for routine CT in paresis might be strengthened from a qualitative

14