Deep venous thrombosis and pulmonary embolism in otolaryngologic patients

PURPOSE

The objective of this study is to present incidence of deep venous thrombosis and pulmonary embolism in otolaryngologic patients and make recommendations on appropriate thromboprophylaxis.

METHODS

The methods used in this study are as follows: 5-year retrospective review in a tertiary care otolaryngology practice and computer-based search from 2000 to 2005. Cases were segregated into ambulatory vs inpatient procedures and malignant vs nonmalignant diagnoses.

RESULTS

Six DVTs were identified, 5 with a diagnosed malignancy. One resulted in pulmonary embolism. Inpatient surgeries (1540) and outpatient surgeries (4582) were performed. Eight hundred twenty-four of these were for malignancies (542 inpatient). The incidence of DVT was 0.1%. The incidence in patients with malignancy was 0.6%.

CONCLUSIONS

Otolaryngology should be considered a specialty with low thromboembolism risk. Based on this study and recommendations by the American College of Chest Physicians (Northbrook, IL), we recommend early mobilization with the possible adjunct of pneumatic compression stockings in most low-risk otolaryngologic procedures, including most of the outpatient procedures. Moderate-risk patients should be considered for either mechanical or pharmacologic prophylaxis. High-risk patients and patients undergoing high-risk procedures are candidates for pharmacologic thromboprophylaxis.

Clinical investigation and mechanism of air-bone gaps in large vestibular aqueduct syndrome

OBJECTIVES

Patients with large vestibular aqueduct syndrome (LVAS) often demonstrate an air-bone gap at the low frequencies on audiometric testing. The mechanism causing such a gap has not been well elucidated. We investigated middle ear sound transmission in patients with LVAS, and present a hypothesis to explain the air-bone gap.

METHODS

Observations were made on 8 ears from 5 individuals with LVAS. The diagnosis of LVAS was made by computed tomography in all cases. Investigations included standard audiometry and measurements of umbo velocity by laser Doppler vibrometry (LDV) in all cases, as well as tympanometry, acoustic reflex testing, vestibular evoked myogenic potential (VEMP) testing, distortion product otoacoustic emission (DPOAE) testing, and middle ear exploration in some ears.

RESULTS

One ear with LVAS had anacusis. The other 7 ears demonstrated air-bone gaps at the low frequencies, with mean gaps of 51 dB at 250 Hz, 31 dB at 500 Hz, and 12 dB at 1,000 Hz. In these 7 ears with air-bone gaps, LDV showed the umbo velocity to be normal or high normal in all 7; tympanometry was normal in all 6 ears tested; acoustic reflexes were present in 3 of the 4 ears tested; VEMP responses were present in all 3 ears tested; DPOAEs were present in 1 of the 2 ears tested, and exploratory tympanotomy in 1 case showed a normal middle ear. The above data suggest that an air-bone gap in LVAS is not due to disease in the middle ear. The data are consistent with the hypothesis that a large vestibular aqueduct introduces a third mobile window into the inner ear, which can produce an air-bone gap by 1) shunting air-conducted sound away from the cochlea, thus elevating air conduction thresholds, and 2) increasing the difference in impedance between the scala vestibuli side and the scala tympani side of the cochlear partition during bone conduction testing, thus improving thresholds for bone-conducted sound.

CONCLUSIONS

We conclude that LVAS can present with an air-bone gap that can mimic middle ear disease. Diagnostic testing using acoustic reflexes, VEMPs, DPOAEs, and LDV can help to identify a non-middle ear source for such a gap, thereby avoiding negative middle ear exploration. A large vestibular aqueduct may act as a third mobile window in the inner ear, resulting in an air-bone gap at low frequencies.