Effects of Bone Metabolic Markers on the Clinical Outcomes of Surgically Treated Superior Semicircular Canal Dehiscence Patients: A Case Series of 250 Repairs

Abstract

Superior semicircular canal dehiscence (SSCD) syndrome is caused by a bony defect in the osseous shell of the arcuate eminence separating the labyrinth and the intracranial space. Recommended treatment for SSCD varies according to the severity of the symptoms and patient age. Due to the potential linkage between osteoporosis and SSCD, additional research observing the relationship between bone metabolic markers (BMMs) and SSCD is warranted. In this retrospective study, we analyze the effect of BMMs, supplementation, and concomitant bone-related pathologies on the clinical outcomes of 250 SSCD patients who were surgically treated via a middle cranial fossa approach/craniotomy between March 2011 and September 2020. At the time of presurgical SSCD consultation, 11 (4.4%) patients had a past medical history (PMH) of osteoporosis, while 5 (2%) patients had osteopenia. PMH of osteoporosis/osteopenia was marginally more prevalent in older patients (rpb = 0.21, p = 0.001), and predominantly in females (14/158) than in males (2/92) (p = 0.057). Patients with osteoporosis had higher rates of preoperative hearing loss (p = 0.02), but with higher rates of hearing loss resolution following surgery (p = 0.051) ([Tables 1]–[4]). Patients with osteoporosis were more likely to have an additional PMH of “arthritis” (rpb = −0.24, p = 0.0002). At the time of pre-surgical SSCD consultation, 29 (12%) patients had a PMH “arthritis,” 5 (2.0%) patients had rheumatoid arthritis, 3 (1.2%) patients had systemic lupus erythematosus, and 8 (3.2%) patients had a variety of other autoimmune conditions. Patients with arthritis had significant higher rates of preoperative disequilibrium/imbalance (p = 0.048) and had marginally lower rates of preoperative dizziness (p = 0.07). Patients with an autoimmune condition had higher rates of oscillopsia resolution following surgery (p = 0.02). Serum calcium values were available for 201 (80%) patients with a mean serum calcium of 9.4 mg/dL (SD = 0.4 mg/dL). Serum calcium levels were marginally associated with a need for second surgery (rpb = −0.13, p = 0.066), and had significant levels in patients presenting with preoperative hearing loss (rpb = 0.16, p = 0.02). Patients receiving calcium supplementation after surgery (n = 122, 49%) had significantly higher rates of postoperative autophony (p = 0.005), lower rates of autophony resolution (p = 0.0005), lower rates of postoperative hyperacusis (P=.04), hyperacusis resolution (p = 0.01), and oscillopsia resolution (p = 0.03). Calcium supplemented patients had marginally lower rates of post-operative vertigo (p = 0.06). Serum 25-hydroxyvitamin D values were available for 53 (21%) patients with a mean value of 35.5 ng/mL (SD = 10.9 ng/mL). Female patients had higher serum vitamin D levels (p = 0.03). Higher levels of serum vitamin D were correlated with a higher preoperative aural fullness rate (rpb = 0.29, p = 0.03) and a lower preoperative disequilibrium/imbalance rate (rpb = −0.32, p = 0.02). Serum albumin values were available for 153 (61%) patients with a mean value of 4.39 g/dL (SD = 0.37 g/dL). Patients with osteoporosis and arthritis both had lower levels of serum albumin (p = 0.001, p = 0.002). Our results indicate that PMH of osteoporosis may influence the clinical course, possible enhancement of SSCD pathophysiology, and that there is an association between BMMs and the clinical outcome of surgically treated SSCD patients. Therefore, these factors should be considered to personalize care for SSCD patients and help guide future studies in this field.