CO2 Laser Myringoplasty: A Minimally Invasive Technique for Treating Tympanic Membrane Atelectasis

Management of retraction pockets: historic and novel approaches

Background

Retraction pockets are collapsed segments of the tympanic membrane. Their formation is associated with a disruption in middle-ear ventilation pathways, leading to the loss of organised collagen of the tympanic membrane. There are several approaches in treating retraction pockets, which aim either to improve ventilation or repair the retraction pockets themselves.

Methods

A review of the literature regarding the classification and associated management of retraction pockets was conducted, using Medline and Cochrane Library databases, with the addition of our institution's experience in undertaking novel techniques.

Results

All the current classification systems fail to guide treatment or prognosticate the disease. Commonly, an initial conservative approach is suggested for early stages, with no clear indication regarding when a surgical solution should be offered. There are conflicting data concerning the effectiveness of these treatments in terms of disease prevention, recurrence and hearing outcomes.

Conclusion

Minimally invasive approaches utilising novel techniques may be key to reducing peri-operative morbidity and improving the overall patient experience.

Effect of Bending of Carbon Dioxide Laser Fibers on Power Output

Objective

The power output from carbon dioxide (CO₂) laser fibers has the potential to be diminished if there are any bends along its course, which may alter the effect the laser has on the target tissue. In this study, we assess how bending of CO₂ laser flexible fiber assemblies affects the energy output measured at the end of the fiber.

Study Design

Laboratory study.

Setting

Laboratory.

Methods

Eight separate flexible fibers were tested—4 were of a type commonly used in endoscopic airway procedures, and the other 4 were a type used in otologic surgery. Fibers were bent in various configurations, and the power output of a CO₂ laser fired through the bent fiber was measured. The output through the bent fiber was normalized to the output with a straight fiber. Correlations between bend parameters and power outputs was tested using Spearman’s correlation coefficient.

Results

For the airway fibers, there was a weak trend toward increasing energy outputs with greater radius of curvature (P = .714) and a negative correlation between the energy output and arc of rotation (P = .043). For the otologic fibers, there was a trend toward increasing energy outputs with greater radius (P = .084) and a strong negative correlation between the energy output and the arc of rotation (P = .006).

Conclusion

CO₂ laser energy output is reduced by bending of the laser fiber assembly. When using the CO₂ laser fiber, surgeons should be aware of any bends in the fiber and are encouraged to take measures to minimize bending.

Use of a flexible hollow-core carbon dioxide laser for microsurgical resection of vestibular schwannomas

OBJECTIVE

The CO2 laser has been used on an intermittent basis in the microsurgical resection of brain tumors for decades. These lasers were typically cumbersome to use due to the need for a large, bulky design since infrared light cannot be transmitted via fiber-optic cables. Development of the OmniGuide cable, which is hollow and lined with an omnidirectional dielectric mirror, has facilitated the reintroduction of the CO2 laser in surgical use in a number of fields. This device allows for handheld use of the CO2 laser in a much more ergonomically favorable configuration, holding promise for microneurosurgical applications. This device was introduced into the authors’ practice for use in the microsurgical resection of skull base tumors, including vestibular schwannomas.

METHODS

The authors reviewed the initial 41 vestibular schwannomas that were treated using the OmniGuide CO2 laser during an 8-month period from March 2010 to October 2010. The laser was used for all large tumors, and select medium-sized tumors were treated via both the translabyrinthine and retrosigmoid approaches. The estimated time of tumor resection and estimated blood loss were obtained from operating room records. Data regarding complications, facial nerve and hearing outcomes, and further treatment were collected from hospital and clinic records, MRI reports, and direct review of MR images. Time of resection and blood loss were compared to a control group (n = 18) who underwent surgery just prior to use of the laser.

RESULTS

A total of 41 patients with vestibular schwannomas were surgically treated. The median estimated time of tumor resection was 150 minutes, and the median estimated blood loss was 300 ml. The only operative complication was 1 CSF leak. Thirty-eight patients had normal facial nerve function at late follow-up. The median MRI follow-up was 52 months, and, during that time, only 1 patient required further treatment for regrowth of a residual tumor.

CONCLUSIONS

The OmniGuide CO2 laser is a useful adjunct in the resection of large vestibular schwannomas. This device was used primarily as a cutting tool rather than for tumor vaporization, and it was found to be of most use for very large and/or firm tumors. There were no laser-associated complications, and the results compared favorably to earlier reports of vestibular schwannoma resection.

Efficacy of continuous positive airway pressure on middle ear atelectasis: A double-blind placebo-controlled clinical trial

OBJECTIVES/HYPOTHESIS

To investigate the effects of continuous positive airway pressure (CPAP) treatment on patients with middle ear atelectasis.

STUDY DESIGN

Prospective, double-blind, randomized, placebo-controlled study.

METHODS

Fifty-four patients with middle ear atelectasis were randomized to receive CPAP treatment with a pressure level of either 14 cm H2 O (CPAP group) or 0 cm H2 O (placebo group) once per week for a period of 3 hours for 4 sessions. Outcome measures included otomicroscopic examination as well as tympanometric and audiometric evaluation. Patients were followed for 6 months.

RESULTS

The CPAP group included 35 atelectatic ears, and the placebo group included 32 atelectatic ears. More ears recovered to normal tympanic membrane or regressed to grade 1 atelectasis in the CPAP group than in the placebo group during all follow-up visits (P < .05). There was a statistically significant increase in the middle ear pressure values of the patients in the CPAP group compared to the placebo group at week 5, month 3, and month 6 (P < .05). There was no significant difference in middle ear pressure values between follow-up visits in the CPAP group (P > .05). Significant improvement of pure-tone air-conduction threshold averages were found in the CPAP group compared to the placebo group at month 6 (P < .05).

CONCLUSIONS

CPAP is a safe, well-tolerated way of applying positive pressure to the middle ear for patients with middle ear atelectasis. It contributes to significant improvement in middle ear pressure of these patients, also resulting in an improved degree of atelectasis.

LEVEL OF EVIDENCE

1b. Laryngoscope, 126:1649-1655, 2016.