Superior semicircular canal dehiscence postoperative outcomes: A case series of 156 repairs

Superior semicircular canal dehiscence postoperative outcomes: a case series of 350 repairs

BACKGROUND

Superior Semicircular Canal Dehiscence (SSCD) is a dehiscence of the otic capsule which normally lies over the superior semicircular canal. This database constitutes the largest series of SSCD patients to date.

OBJECTIVE

To determine what preoperative factors, if any, contribute to postoperative outcomes and evaluate symptom resolution in a large SSCD patient cohort.

METHODS

A single-institution, retrospective chart review collected patient demographics, intraoperative findings, and pre-and postoperative symptoms. Fisher's exact t-test was performed for unpaired categorical variables, with a significance level of p < 0.05.

RESULTS

350 SSCD repairs were performed. The median age was 52 years (range: 17-86 years, ± 6.4 years), and the median follow-up duration was 4.6 months (range: 0.03-59.5 months, ± 6.8 months). Preoperative hearing loss was significantly associated with female sex (p = 0.0028). The most reported preoperative symptoms were tinnitus (77.4%), dizziness (74.0%), autophony (66.3%), amplification (63.7%), and disequilibrium (62.6%). Between patients who received unilateral versus bilateral SSCD repair, the greatest postoperative symptomatic resolution was seen in autophony (74.9%, p < 0.001), amplification (77.3%, p = 0.00027), hyperacusis (77.4%, p = 0.023), hearing (62.9%, p = 0.0063), and dizziness (54.6%, p < 0.001) for patients with unilateral SSCD repair.

CONCLUSION

Surgical repair via the middle cranial fossa approach can significantly resolve auditory, vestibular, and neurological symptoms of patients with SSCD. Although this is one of the largest single-institution SSCD studies to date, future multi-institutional, prospective studies would be beneficial to validate these results.

Traumatic Events Preceding the Development of Superior Canal Dehiscence Syndrome

OBJECTIVE

To describe the features of antecedent head trauma in patients with superior canal dehiscence syndrome (SCDS).

STUDY DESIGN

Cross-sectional survey.

SETTING

Tertiary referral center.

METHODS

An online survey was sent to 450 adult patients who underwent surgical repair for SCDS patients asking questions about the nature of internal or external traumatic events preceding symptoms.

RESULTS

One-hundred and thirty-six patients (avg. age, 51.9 years, 62.8% female) completed the survey, of which 61 (44.9%) described either preceding external head trauma (n = 35, 26%), preceding internal pressure event (n = 33, 25%), or both (8, 6%). Of those endorsing external trauma, 22 (63%) described a singular event (head hit by object (n = 8); head hit ground (n = 5); motor vehicle accident (n = 4); assault (n = 2); other (n = 3). One-third experienced loss of consciousness because of the trauma. For those describing internal pressure events (n = 33), the most common events were heavy physical exertion (9, 27%); pressure changes while flying (6, 18%); coughing, nose blowing with illness (5, 15%); childbirth (5, 15%); and self contained underwater breathing apparatus diving events (3, 9%). The interval between trauma and onset of symptoms averaged 5.6 years (SD, 10.7 years). One-third (n = 19) described onset of symptoms immediately after the external trauma or internal pressure event. Symptoms began on the side ipsilateral to the trauma in 91%. Sound- and pressure-induced vertigo/oscillopsia developed more commonly after external trauma versus internal pressure events (68% and 61% vs 44% and 32%, respectively).

CONCLUSION

Trauma or internal pressure-related events precede SCDS symptoms in nearly half of cases, with roughly half of preceding events being external.

Auditory and Vestibular Symptom Improvement With Surgery for Superior Canal Dehiscence Syndrome

OBJECTIVE

(1) To measure the change in auditory and vestibular symptoms following superior canal dehiscence (SCD) surgery, and (2) to determine differences in clinical features and surgical outcomes between superior canal dehiscence syndrome (SCDS) patients with primarily auditory or vestibular complaints.

STUDY DESIGN

Retrospective cohort study.

SETTING

Single surgeon series at the tertiary academic medical center from 2002 to 2021.

METHODS

Retrospective review of SCDS patients who underwent surgical repair. (1) Patients were administered a standardized symptom questionnaire at preoperative and follow-up visits, and results were compared with paired statistical testing. (2) Patients were divided into 2 cohorts based on either auditory or vestibular chief complaint and differences in demographic, clinical, and outcome variables were examined.

RESULTS

Our study included 113 patients with 118 operated ears. Twenty-seven patients (24%) had radiographic bilateral dehiscence. 10/11 auditory symptoms (91%) and 5/8 vestibular symptoms (63%) solicited on the questionnaire improved significantly with surgery, except for nonpulsatile tinnitus, sense of imbalance, positional dizziness, and oscillopsia. Analyses stratified by chief complaint (auditory vs vestibular) revealed overall similar characteristics and surgical outcomes. Patients with chief vestibular complaints underwent surgery at an earlier age (45.5 vs 53.9 years, p < 0.05).

CONCLUSION

SCD surgery alleviates a wide range of auditory and vestibular symptoms. Overall, we did not find significant differences between patients with chief auditory versus vestibular complaints, and both groups benefited from surgery. Symptoms are not directly linked to third-window physiology and certain vestibular symptoms may be more likely to persist. Bilateral dehiscence may play an important role in persistent symptoms as well.

Postoperative Outcomes of Patients with Thin Bone Overlying the Superior Semicircular Canal: A Single Institution's Experience

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is defined by a bony defect overlying the superior semicircular canal (SSC) in the middle cranial fossa floor, causing a myriad of vestibular and auditory symptoms. Patients with thin bone without full dehiscence overlying the SSC also present with similar symptoms. There are currently no guidelines for surgical management of patients with thin bone. The authors offer their experience with thin bone patients to characterize their symptomatology and explore whether these patients benefit from surgical intervention typically offered to SSCD patients.

METHODS

Two hundred fifty-six patients evaluated for SSCD from 2011 to 2019 were reviewed. High-resolution coronal computed tomography scans with 0.6-mm slice thickness of the temporal bones were assessed to determine whether the patient had a true dehiscence or a thin bone covering overlying the SSC. Bone that was ≤0.5 mm was considered to be "thin bone." Parameters of interest included patient demographics as well as preoperative and postoperative symptomatology. A P value < 0.05 was considered statistically significant.

RESULTS

Forty-eight patients met inclusion criteria of having "thin bone." The mean age was 48.13 ± 12.03 years, and 65.5% of patients were female. Of the preoperative symptoms evaluated, the greatest postoperative symptomatic resolution was noted in hearing loss (92.3%), vertigo (94.4%), and oscillopsia (100%). Dizziness (56.5%) had the lowest symptomatic resolution rate.

CONCLUSIONS

Surgical management of thin bone patients via middle fossa craniotomy, a similar technique to SSCD repair, provides significant symptomatic resolution. Therefore, surgery should be considered in thin bone patients with debilitating symptoms, albeit not having a true dehiscence.

Assessment of Metabolic Markers and Osteoporosis in 250 Patients with Superior Semicircular Canal Dehiscence Treated With Middle Fossa Craniotomy

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is caused by bony defects in the osseous shell of the arcuate eminence separating the labyrinth and the intracranial space. This pathologic third window causes hydroacoustic transmission resulting in debilitating symptoms. We examine the pathophysiologic association between metabolic markers, previous medical history, and SSCD symptoms before and after middle fossa craniotomy (MFC) treatment.

METHODS

This study was conducted between March 2011 and September 2020 with patients with SSCD who underwent MFC. We used a Fisher test to compare variables, including bilateral SSCD, second surgery, ear anomaly, osteoporosis, arthritis, vitamin D, and preoperative/postoperative symptoms, and others. Point-biserial correlation analysis was performed to test correlations between continuous variables and categorical variables.

RESULTS

A total of 250 patients with SSCD underwent MFC repair. There was significant postoperative resolution in all symptoms (P < 0.0001). Laboratory 25-hydroxyvitamin D values correlated with preoperative aural fullness (r_pb= 0.29; P = 0.03), and preoperative disequilibrium (r_pb= -0.32; P = 0.02). Serum calcium values correlated with preoperative hearing loss (r_pb= 0.16; P = 0.02). Osteoporosis history (n = 16; 6%) was more prevalent in female patients (P = 0.0001), associated with higher levels of preoperative hearing loss (odds ratio, 4.56; P = 0.02) and higher postoperative hearing loss resolution (odds ratio, 2.89; P = 0.0509).

CONCLUSIONS

Certain metabolic markers may predict SSCD presentation before and after surgery. Previous history of osteoporosis, autoimmune conditions, or arthritis may play a role in SSCD pathophysiology and can help predict clinical outcomes. Future evaluation should take metabolic laboratory values and acquire an exact medical history.

Superior Semicircular Canal Dehiscence Syndrome Following Head Trauma: A Multi-institutional Review

OBJECTIVE

To evaluate patients who become symptomatic from superior semicircular canal dehiscence (SSCD) following head trauma.

STUDY DESIGN

Case series assessing patients presenting with SSCD after a trauma.

METHODS

A case series was completed assessing patients presenting with SSCD after trauma. Data from three academic medical centers were evaluated, including the following: imaging, videonystagmography (VNG)/vestibular evoked myogenic potential (VEMP) testing, audiometric assessment, and surgical repair. Outcome measures included the following: 1) Description of audio-vestibular symptoms, 2) mean pre- and post-operative pure tone average (PTA), word recognition score (WRS), and air bone gap (ABG).

RESULTS

A total of 14 patients were included; 86% were male. Approximately 43% were found to have bilateral SSCD on imaging, with 57% of patients pursuing surgical management. The most common presenting symptoms included pulsatile tinnitus (93%), autophony (79%), and hearing loss (64%). Approximately 36% of patients underwent VNG/VEMP testing, with 83.3% of those demonstrating abnormal results. The mean audiometric findings on the symptomatic side included an air-conduction PTA of 38.0 dB, bone-conduction PTA of 24.3 dB, WRS of 81%, and ABG of 17.9 dB. Among patients who underwent surgery (57%), there was no significant change in the air-conduction PTA, bone-conduction PTA, or WRS (P > .05). However, there was an improvement in the ABG (preoperative = 22.8 dB versus postoperative = 9.7 dB; P = .005).

CONCLUSION

Head trauma may be a potentiating event for SSCD syndrome. This study advances the hypothesis that these patients likely have underlying radiographic SSCD prior to their trauma, and a traumatic event increases in intra-vestibular or intracranial pressures, unmasking SSCD syndrome.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E2810-E2818, 2021.

Selective scalp block decreases short term post-operative pain scores and opioid use after craniotomy: A case series

There is no consensus on the management of post-craniotomy pain. Several randomized controlled trials have examined the use of a regional scalp block for post-craniotomy pain. We aim to investigate whether scalp block affected short or long-term pain levels and opioid use after craniotomy. This study prospectively administered selective scalp blocks (lesser occipital, preauricular nerve block + pin site block) in 20 consecutive patients undergoing craniotomy for semicircular canal dehiscence. Anesthesia, pain, and opioid outcomes in these patients were compared to 40 consecutive historic controls. There was no significant difference in patient demographics between the two groups and no complications related to selective scalp block. The time between the end of procedure and end of anesthesia decreased in the scalp block group (16 vs 21 min, P = 0.047). Pain scores were significantly less in the scalp block group for the first 4 h, after which there was no statistically significant difference. Time to opioid rescue was longer in the scalp block group (3.6 vs 1.8 h, HR 0.487, P = 0.0361) and opioid use in the first 7 h was significantly less in the scalp block group. Total opioid use, outpatient opioid use, and length of stay did not differ. Selective scalp block is a safe and effective tool for short-term management of postoperative pain after craniotomy and decreases the medication requirement during emergence and recovery. Selective scalp block can speed up OR turnover but is not efficacious in the treatment of postoperative pain beyond this point.

Superior Semicircular Canal Dehiscence Revision Surgery Outcomes: A Single Institution's Experience

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is an abnormality of the otic capsule, which normally overlies the superior semicircular canal. Surgical management is indicated in patients with persistent and debilitating symptoms. Given the complexity of the disease, there are patients who experience less favorable surgical outcomes and require revision surgery. The purpose of this study was to report to the rate of postoperative symptomatic improvement in patients who required revision surgery.

METHODS

A retrospective analysis of patients undergoing SSCD surgical repair at a single institution was performed. Information on patient demographics, primary and secondary surgical approaches, surgical outcomes, and follow-up length was collected.

RESULTS

Seventeen patients underwent 20 revision surgeries. There were eleven (65%) females and six (35%) males. Mean age of the cohorts was 50 years (range 30-68 years), and mean follow-up length was 6.8 months (range 0.1-31.1 months). Cerebrospinal fluid leak was noted in 67% of cases. The greatest postoperative symptomatic resolution was reported in oscillopsia (100%), headache (100%), and internal sound amplification (71%), while the least postoperative symptomatic resolution was reported in tinnitus (42%), aural fullness (40%), and dizziness (29%).

CONCLUSIONS

Revision surgery can provide symptomatic improvement in select SSCD patients; however, patients should be cautioned about the possibility of less favorable outcomes than in index surgery. Revision surgeries are associated with a considerably higher rate of perioperative cerebrospinal fluid leak.

Relationship Between Superior Semicircular Canal Dehiscence Volume with Clinical Symptoms: Case Series

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is an osseous defect of the arcuate eminence of the petrosal temporal bone. Patients typically present with auditory and vestibular symptoms, such as hearing loss and disequilibrium. Using advanced imaging segmentation techniques, we evaluated whether the volume of SSCD correlated with preoperative symptoms and postoperative outcomes.

METHODS

Our laboratory previously described a novel method of quantifying the size of an SSCD via manual segmentation. High-resolution computed tomography images of the temporal bones were imported into a specialized segmentation software. The volume of the dehiscence was outlined on consecutive slices of the coronal and axial planes via a single-pixel-thick paintbrush tool and was then calculated according to the number of nonzero image voxels.

RESULTS

This study included 111 patients (70 women and 41 men; mean age, 55.1 years; age range, 24-87 years) with a total of 164 SSCDs. Mean postoperative follow-up time was 5.2 months (range, 0.03-59.5 months). The most common preoperative and postoperative symptoms were tinnitus (n = 85) and dizziness (n = 45), respectively. Surgery resulted in improvement of symptoms in most patients. The average volume of 164 SSCDs was 1.3 mm³. SSCD volume was not significantly associated with either preoperative symptoms or postoperative outcomes.

CONCLUSIONS

Advances in imaging techniques have allowed increased visualization of SSCD. Further research will be necessary to evaluate the potential correlation of volume of the dehiscence with clinical variables.

Superior Semicircular Canal Dehiscence Outcomes in a Consecutive Series of 229 Surgical Repairs With Middle Cranial Fossa Craniotomy

BACKGROUND

Superior semicircular canal dehiscence (SSCD) is the appearance of a third mobile window between the middle fossa and the superior semicircular canal. Surgical management is indicated in patients with persistent and debilitating symptoms. The purpose of this study was to evaluate the association between preoperative variables that may impact postoperative symptomatic resolution.

METHODS

A single-institution retrospective analysis was performed on patients who were surgically treated for SSCD. Patients were divided to different cohorts based on unilateral or bilateral nature of the disease. A P value <0.05 was considered statistically significant.

RESULTS

A total of 229 surgical repairs were analyzed. Mean age was 51 years (± 7.8 years), and 55.9% of patients were female. All cohorts were similar with respect to baseline demographics. The most commonly reported preoperative symptoms were tinnitus, dizziness, and autophony. The greatest symptomatic resolution was seen in autophony, internal sound amplification, hyperacusis, and oscillopsia. The unilateral SSCD cohort had significantly higher improvement of autophony (P = 0.003), aural fullness (P = 0.05), tinnitus (P = 0.006), hearing loss (P = 0.02), dizziness (P = 0.006), and headache (P = 0.007), compared with the bilateral SSCD cohorts. Among patients with bilateral disease, those with unilateral surgery reported greater symptomatic resolution with respect to hyperacusis (P = 0.03), hearing loss (P = 0.02), dizziness (P = 0.03), and disequilibrium (P < 0.001), than those with bilateral operations.

CONCLUSIONS

Surgical management of SSCD leads to high rates of postoperative symptomatic improvement. Patients with unilateral SSCD benefit greater symptomatic resolution compared to those with bilateral pathology.