Delayed facial palsy following laser stapedectomy: in vitro study of facial nerve temperature

Conventional vs. diode laser stapedotomy: audiological outcomes and clinical safety

PURPOSE

To compare the hearing results and clinical safety of patients undergoing stapes surgery with conventional technique and diode laser.

METHODS

Retrospective observational study, which included patients treated with primary stapes surgery performed between January 2009 and January 2020. Three audiometric measurements (PTA, GAP and SDS) were evaluated as main results, evaluated by analysis of covariance (controlling the preoperative value). Intraoperative and postoperative complications were also analyzed. Outcomes were measured 6 months (± 1 month) after surgery.

RESULTS

153 cases were included, 97 operated with conventional technique and 56 with laser technique. Postoperative GAP ≤ 10 dB was obtained in 85.6% of the total sample, 82.5% in the conventional technique and 91.1% in the laser technique. Analysis of covariance showed no significant differences in the three surgery outcomes between the two groups (PTA, p = 0.277; GAP, p = 0.509 and SDS, p = 0.530). Regarding surgical complications, sensorineural damage was higher in the conventional technique group (p = 0.05). On the other hand, there were four cases of facial paresis, all in the laser group, three of them with the 980 nm laser.

CONCLUSIONS

Stapedotomy offered a high percentage of hearing success in the two groups studied. There were no significant differences in audiometric result, but there was a differential presentation of complications, being more frequent sensorineural hearing loss in the conventional technique group and facial paresis in the laser group.

Typical or Atypical Ramsay-Hunt Syndrome in Delayed Facial Palsy After Stapedectomy?

OBJECTIVES

The aim of this study was to define the typical pattern for varicella zoster virus (VZV) reactivation in delayed facial palsy (DFP) after stapedectomy for otosclerosis.

MATERIALS AND METHODS

Review of the relevant literature, personal casistics, and case-report.

RESULTS

In total, 48 cases of DFP after stapes surgery have been described so far, including the reported case with exclusive manifestation of atypical Ramsay Hunt syndrome (RH); in the personal series of 1253 stapedectomies, DFP occurred in only one case (0.08%). Complete DFP (House-Brackmann grade VI) rapidly developed 12 days after surgery; RH appeared 2 days later, confirming the role of VZV. The DFP started improving after 8 weeks and completely recovered 6 months later.

CONCLUSION

Acute otalgia prior to DFP should raise the suspicion of VZV reactivation. Atypical RH is the most frequent pattern that occurs in DFP after stapedectomy.

Use of the flexible fiber CO2 laser in pediatric transcanal endoscopic middle ear surgery

We describe 4 pediatric patients (age 6-11 years) who underwent transcanal endoscopic ear surgery (TEES) with the assistance of a flexible fiber CO2 laser over a period of 6 months. Three of these individuals suffered from densely adherent cholesteatoma, where the laser permitted one-handed dissection while preserving endoscopic visualization by limiting bleeding. In the fourth patient, TEES ossiculoplasty was performed for a congenital stapes bar, with subsequent hearing improvement. Advantages and disadvantages of the flexible fiber CO2 laser in the setting of TEES are discussed. Use of the flexible fiber CO2 laser was found to expand the TEES toolkit.

Delayed Facial Paralysis following Uneventful KTP Laser Stapedotomy: Two Case Reports and a Review of the Literature

Facial palsy that occurs immediately after middle ear surgery (stapedectomy, stapedotomy, and tympanoplasty) can be a consequence of the local anesthetics and it regresses completely within a few hours. In the case of delayed facial palsy, the alarming symptom occurs several days or even weeks after uneventful surgery. The mechanism of the neural dysfunction is not readily defined. Surgical stress, intraoperative trauma, or laceration of the chorda tympani nerve with a resultant retrograde facial nerve edema can all be provoking etiological factors. A dehiscent bony facial canal or a multiple microporotic fallopian canal (microtrauma or laser effect) can also contribute to the development of this rare phenomenon. The most popular theory related to the explanation of delayed facial palsy at present is the reactivation of dormant viruses. Both the thermal effect of the laser and the elevation of the tympanomeatal flap can reactivate viruses resting inside the ganglion geniculi, facial nerve, or facial nuclei. The authors report the case histories of a 55-year-old female, and a 45-year-old male who presented with a delayed facial palsy following laser stapedotomy. The clinical characteristics, the therapeutic options, and the possibility of prevention are discussed.

The effects of dexamethasone and acyclovir on a cell culture model of delayed facial palsy

HYPOTHESIS

Pretreatment with antiherpetic medications and steroids decreases likelihood of development of delayed facial paralysis (DFP) after otologic surgery.

BACKGROUND

Heat-induced reactivation of herpes simplex virus type 1 (HSV1) in geniculate ganglion neurons (GGNs) is thought to cause of DFP after otologic surgery. Antiherpetic medications and dexamethasone are used to treat DFP. Pretreatment with these medications has been proposed to prevent development of DFP.

METHODS

Rat GGN cultures were latently infected with HSV1 expressing a lytic protein-GFP chimera. Cultures were divided into pretreatment groups receiving acyclovir (ACV), acyclovir-plus-dexamethasone (ACV + DEX), dexamethasone alone (DEX), or untreated media (control). After pretreatment, all cultures were heated 43°C for 2 hours. Cultures were monitored daily for reactivation with fluorescent microscopy. Viral titers were determined from culture media.

RESULTS

Heating cultures to 43°C for 2 hours leads to HSV1 reactivation and production of infectious virus particles (59 ± 6.8%); heating cultures to 41°C showed a more variable frequency of reactivation (60 ± 40%), compared with baseline rates of 14.4 ± 5%. Cultures pretreated with ACV showed lower reactivation rates (ACV = 3.7%, ACV + DEX = 1.04%) compared with 44% for DEX alone. Viral titers were lowest for cultures treated with ACV or ACV + DEX.

CONCLUSION

GGN cultures harboring latent HSV1 infection reactivate when exposed to increased temperatures that can occur during otologic surgery. Pretreatment with ACV before heat provides prophylaxis against heat-induced HSV reactivation, whereas DEX alone is associated with higher viral reactivation rates. This study provides evidence supporting the use of prophylactic antivirals for otologic surgeries associated with high rates of DFP.

Pressure and temperature changes in in vitro applications with the laser and their implications for middle ear surgery

Background. The purpose of this study was to evaluate the thermal and pressure effects using a Titan Sapphire chirped-pulse amplifier system configured to deliver ultrashort pulses of 180 femtoseconds (fs) in an inner ear model. Materials and Methods. Temperature increases and heat exchange processes in the fluid (physiological saline) were examined in a calorically and physiologically approximated cochlea model for applying laser parameters effective in the creation of footplate perforations. Results. In the effective energy density range, the highest temperature increases achieved with the Carbon dioxide (CO₂) laser were about 11 degrees C. The lowest temperature maxima were 6 degrees C with the Er:YAG laser (Yttrium-Aluminum-Oxide doted with Erbium3+-ions) and <5 degrees C with the femtosecond laser. Comparison of the laser-induced pressure with the limit graph published by Pfander indicated that the use of the fs laser is unobjectionable for fluences <1 J/cm². Conclusions. Our investigations demonstrated that the application of the fs laser in middle ear surgery presents a new and promising addition to the range of ultrashort wavelength lasers used for this purpose.

Morphological effects of nanosecond- and femtosecond-pulsed laser ablation on human middle ear ossicles

We evaluate the feasibility of nanosecond-pulsed and femtosecond-pulsed lasers for otologic surgery. The outcome parameters are cutting precision (in micrometers), ablation rate (in micrometers per second), scanning speed (in millimeters per second), and morphological effects on human middle ear ossicles. We examine single-spot ablations by a nanosecond-pulsed, frequency-tripled Nd:YAG laser (355 nm, beam diameter 10 microm, pulse rate 2 kHz, power 250 mW) on isolated human mallei. A similar system (355 nm, beam diameter 20 microm, pulse rate 10 kHz, power 160-1500 mW) and a femtosecond-pulsed CrLi:SAF-Laser (850 nm, pulse duration 100 fs, pulse energy 40 microJ, beam diameter 36 microm, pulse rate 1 kHz) are coupled to a scanner to perform bone surface ablation over a defined area. In our setups 1 and 2, marginal carbonization is visible in all single-spot ablations of 1-s exposures and longer: With an exposure time of 0.5 s, precise cutting margins without carbonization are observed. Cooling with saline solution result is in no carbonization at 1500 mW and a scan speed of 500 mms. Our third setup shows no carbonization but greater cutting precision, although the ablation volume is lower. Nanosecond- and femtosecond-pulsed laser systems bear the potential to increase cutting precision in otologic surgery.