Perioperative analgesia for patients undergoing otologic surgery: An evidence-based review

OBJECTIVES/HYPOTHESIS

Opioid misuse and diversion is a major concern, with a negative impact on both the individual and society. The objective of this study was to perform an evidence-based systematic review of the efficacy of perioperative analgesic regimens following otologic surgery.

METHODS

Embase, Cochrane Library, and PubMed/MEDLINE databases (January 1, 1947 to June 30, 2018) were searched for studies investigating pain management in otologic surgeries. All studies were assessed for quality and bias using the Cochrane bias tool. Patient demographics, type of surgery, medication class, dose, administration characteristics, pain scores, and adverse events were reported.

RESULTS

Twenty-three studies encompassing 1,842 patients met inclusion criteria. In 21.4% of studies, an overall reduction in pain scores was reported when the treatment group included more than one analgesic. Nausea and vomiting were the most common adverse events across all medication types (10.2%), with local anesthetic patients experiencing these side effects most frequently (38.0%). Perioperative acetaminophen was reported to have the fewest adverse drug reactions overall (6.1%), but did not reduce pain scores as much as other modalities, such as nonsteroidal anti-inflammatory drugs (NSAIDs) or combination analgesics.

CONCLUSIONS

There is evidence that combination analgesics, such as acetaminophen plus codeine, provide superior pain relief to monotherapy analgesics in the perioperative pain management of otologic surgeries. NSAIDs, α-agonists, and nerve blocks may also be viable single-therapy options. Further prospective randomized controlled trials into perioperative analgesia for patients undergoing otologic surgery may be helpful in establishing a definitive consensus. Laryngoscope, 130:190-199, 2020.

Activation of CHK1 in Supporting Cells Indirectly Promotes Hair Cell Survival

The sensory hair cells of the inner ear are exquisitely sensitive to ototoxic insults. Loss of hair cells after exposure to ototoxic agents causes hearing loss. Chemotherapeutic agents such as cisplatin causes hair cell loss. Cisplatin forms DNA mono-adducts as well as intra- and inter-strand DNA crosslinks. DNA cisplatin adducts are repaired through the DNA damage response. The decision between cell survival and cell death following DNA damage rests on factors that are involved in determining damage tolerance, cell survival and apoptosis. Cisplatin damage on hair cells has been the main focus of many ototoxic studies, yet the effect of cisplatin on supporting cells has been largely ignored. In this study, the effects of DNA damage response in cochlear supporting cells were interrogated. Supporting cells play a major role in the development, maintenance and oto-protection of hair cells. Loss of supporting cells may indirectly affect hair cell survival or maintenance. Activation of the Phosphoinositide 3-Kinase (PI3K) signaling was previously shown to promote hair cell survival. To test whether activating PI3K signaling promotes supporting cell survival after cisplatin damage, cochlear explants from the neural subset (NS) Cre Pten conditional knockout mice were employed. Deletion of Phosphatase and Tensin Homolog (PTEN) activates PI3K signaling in multiple cell types within the cochlea. Supporting cells lacking PTEN showed increased cell survival after cisplatin damage. Supporting cells lacking PTEN also showed increased phosphorylation of Checkpoint Kinase 1 (CHK1) levels after cisplatin damage. Nearest neighbor analysis showed increased numbers of supporting cells with activated PI3K signaling in close proximity to surviving hair cells in cisplatin damaged cochleae. We propose that increased PI3K signaling promotes supporting cell survival through phosphorylation of CHK1 and increased survival of supporting cells indirectly increases hair cell survival after cisplatin damage.

R450 – Manganese Superoxide Dismutase in Spiral Ganglion Cells

Problem

Manganese superoxide dismutase (Mn SOD2) is a key metabolic anti-oxidant enzyme of the superoxide dismutase family for detoxifying the free radical cascade inside the mitochondria of the cochlea via activation of downstream uncoupling proteins. Copper/zinc superoxide dismutase (Cu/Zn SOD1) is localized in the cytoplasm. This study examined whether the pattern of expression of these SODs in the cochlea is correlated with the differential cellular vulnerability found in basal versus apical turn of the cochlea.

Methods

Immunohistochemical methods were used to identify the distribution of Mn SOD2 and Cu/Zn SOD1 in paraffin embedded sections of paraformaldehyde fixed formic acid decalcified temporal bones from mice, rats, and macaques; and special archival celloidin-embedded human temporal bone sections.

Results

In mice, rats and macaques, both the proportion of Mn SOD2 immunopositive type 1 spiral ganglion cells and the intensity of immunoreactivity were elevated near the cochlear apex. Strongly stained Mn SOD2 type 1 spiral ganglion cells were also observed in archival human temporal bone sections. In contrast, the Cu/Zn SOD1 immunopositive type 1 spiral ganglion cells were distributed identically across cochlear turns in rats and macaques.

Conclusion

These findings suggest that spiral ganglion cellular responses to ROS exposure may vary along the cochlear spiral, with a lower response capacity in the basal turn.

Significance

Hair cells and spiral ganglion cells appear to be more vulnerable to ototoxins at the base of the cochlea than at the apex. Our data raises the general hypothesis that a lower Mn SOD2 anti-oxidative capacity at the cochlear base could contribute to the high frequency hearing loss seen in presbycusis and ototoxin-induced hearing loss. The conservative pattern of Mn SOD2 immunostaining across species further suggests that it may be a fundamental mechanism in ROS metabolism and signaling.

Support

PA Lions Hearing Research Foundation, American Otologic Society Research Fellowship.