Recent surgical options for vestibular vertigo

Vertigo is not a well-defined disease but a symptom that can occur in heterogeneous entities diagnosed and treated mainly by otolaryngologists, neurologists, internal medicine, and primary care physicians. Most vertigo syndromes have a good prognosis and management is predominantly conservative, whereas the need for surgical therapy is rare, but for a subset of patients often the only remaining option. In this paper, we describe and discuss different surgical therapy options for hydropic inner ear diseases, Menière's disease, dehiscence syndromes, perilymph fistulas, and benign paroxysmal positional vertigo. At the end, we shortly introduce the most recent developments in regard to vestibular implants. Surgical therapy is still indicated for vestibular disease in selected patients nowadays when conservative options did not reduce symptoms and patients are still suffering. Success depends on the correct diagnosis and choosing among different procedures the ones going along with an adequate patient selection. With regard to the invasiveness and the possible risks due to surgery, in depth individual counseling is absolutely necessary. Ablative and destructive surgical procedures usually achieve a successful vertigo control, but are associated with a high risk for hearing loss. Therefore, residual hearing has to be included in the decision making process for surgical therapy.

Cadaveric Study of an Endoscopic Keyhole Middle Fossa Craniotomy Approach to the Superior Semicircular Canal

OBJECTIVE

Demonstrate that an endoscopic keyhole approach to the middle cranial fossa is technically feasible for repair of semicircular canal dehiscence.

STUDY DESIGN

Cadaveric technical feasibility/methods development study.

SETTING

Tertiary care military medical center.

PATIENTS

Three fresh cadaveric heads (six sides).

INTERVENTION(S)

Endoscopic minimally invasive approach to the middle cranial fossa using the Medtronic Fusion Guidance system.

MAIN OUTCOME MEASURE(S)

Ability to identify the surgical landmarks of the middle cranial fossa and successfully identify and instrument the superior semicircular canal.

RESULTS

In every attempt, the arcuate eminence was successfully identified under endoscopic visualization and with the assistance of surgical navigation. The superior semicircular canal was unroofed, and its location confirmed visually and with the navigation system. The opened canal was then plugged with bone wax, bone pate, and covered with fascia. The 15-mm burr hole craniotomy provided ample room for one working instrument and a 4-mm 0-degree endoscope.

CONCLUSION

The endoscopic keyhole approach to superior semicircular canal dehiscence is technically feasible in a human cadaveric model. Further studies will determine 1) if this approach is possible and safe in vivo, 2) is associated with improved surgical outcomes, and 3) if surgical navigation aids in this approach.

Outcomes of middle fossa craniotomy for the repair of superior semicircular canal dehiscence

Superior semicircular canal dehiscence (SSCD) is a rare defect of the arcuate eminence that causes an abnormal connection between the superior semicircular canal and middle cranial fossa. Patients often present with a variety of auditory and vestibular symptoms. Trigger avoidance is the initial strategy, but surgery may be necessary in debilitating cases. We retrospectively reviewed SSCD patients undergoing repair via a middle fossa craniotomy between March 2011 and September 2015. Forty-nine patients undergoing 58 surgeries were identified. Autophony was the most common symptom at presentation (n=44; 90%). Mean follow-up was 10.9months, with 100% of patients reporting resolution of at least one symptom. Aural fullness was the most commonly resolved symptom following surgical repair (n=19/22; 86%). Hearing loss (n=11/25; 44%) and tinnitus (n=11/38; 29%) were the most common symptoms to persist following surgery. The most common symptom to develop after surgery was disequilibrium (n=4/18; 22%). Upon comparing the overall pre-operative and post-operative groups, the number of patients with autophony (p<0.0001), aural fullness (p=0.0006), hearing loss (p=0.0119), disequilibrium (p=0.0002), sound- and pressure-induced vertigo (p<0.0001), and tinnitus (p<0.0001) were significantly different. Improved clinical outcomes were demonstrated in patients undergoing SSCD repair through a middle cranial fossa approach. The most common presenting symptom (autophony) was also most likely to resolve after surgery. Hearing loss is less amenable to surgical correction. Disequilibrium developed in a small number of patients after repair.

Superior semicircular canal dehiscence syndrome

Superior semicircular canal dehiscence (SSCD) syndrome is an increasingly recognized cause of vestibular and/or auditory symptoms in both adults and children. These symptoms are believed to result from the presence of a pathological mobile "third window" into the labyrinth due to deficiency in the osseous shell, leading to inadvertent hydroacoustic transmissions through the cochlea and labyrinth. The most common bony defect of the superior canal is found over the arcuate eminence, with rare cases involving the posteromedial limb of the superior canal associated with the superior petrosal sinus. Operative intervention is indicated for intractable or debilitating symptoms that persist despite conservative management and vestibular sedation. Surgical repair can be accomplished by reconstruction or plugging of the bony defect or reinforcement of the round window through a variety of operative approaches. The authors review the etiology, pathophysiology, presentation, diagnosis, surgical options, and outcomes in the treatment of this entity, with a focus on potential pitfalls that may be encountered during clinical management.

Gender and laterality in semicircular canal dehiscence syndrome

OBJECTIVE

To determine if there is gender or laterality predilection in patients with semicircular canal dehiscence syndrome.

METHODS

A multi-institutional chart review was performed to identify patients diagnosed with semicircular canal dehiscence between 2000 and 2015. A systematic literature search was conducted using PubMed to further identify patients with semicircular canal dehiscence. Age, gender and laterality data were collected. Statistical analysis was performed to evaluate for gender or laterality preponderance.

RESULTS

A total of 682 patients with semicircular canal dehiscence were identified by literature and chart review. Mean age of diagnosis was 49.75 years (standard deviation = 15.33). Semicircular canal dehiscence was associated with a statistically significant female predominance (chi-square = 7.185, p = 0.007); the female-to-male ratio was 1.2 to 1. Left-sided semicircular canal dehiscence was most common, followed by right-sided then bilateral (chi-square = 23.457, p < 0.001).

CONCLUSION

Semicircular canal dehiscence syndrome is most commonly left-sided and exhibits a female predominance. This may be secondary to morphological cerebral hemisphere asymmetries in both sexes and a predilection of women to seek more medical care than men.

Radiographic Assessment and Surgical Implications of Arcuate Eminence Pneumatization

BACKGROUND

The middle cranial fossa (MCF) approach is a valuable yet technically challenging technique. Identification of the superior semicircular canal (SCC) using the arcuate eminence (AE) was proposed as a surface landmark. However, the AE is sometimes absent, with inconsistent relationship to the SCC. Air cells in the AE area facilitate safer identification of the SCC. The aim of this study is to determine the radiographic prevalence of AE pneumatization.

METHODS

Two hundred consecutive fine-cut temporal bone CT scans were retrospectively reviewed. The region of the petrosal bone at and above the level of the SCC dome was assessed for the presence of air cells, and graded 0 (no pneumatization) to 2 (well pneumatized).

RESULTS

Four hundred temporal bones were studied. The average age was 49 years (range 18-89). Of all AE assessments, 47 (12%) were nonpneumatized, 62 (15%) partially pneumatized, and 291 (73%) well pneumatized. There was no significant correlation between patient age and pneumatization grade (p = 0.72).

CONCLUSION

The SCC is a valuable landmark in MCF surgery as it holds consistent relationships to adjacent critical structures. Surrounding air cells should facilitate safer initial identification of the SCC, as the AE region is well pneumatized in 73% of patients.

[Superior semicircular canal dehiscence syndrome treated by calcium phosphate cement canal plugging: a case report]

Superior semicircular canal dehiscence (SCD) syndrome exhibits pressure- and/or sound-induced oscillopsia and vertigo due to an absence of bone overlaying the superior semicircular canal. A 33-year-old man with right-ear SCD reported dizziness in a noisy hall three years earlier followed by dizziness during flatulence, straining or coughing, and right-ear autophony. Audiography showed a right-ear low-frequency air-bone gap, with positive Tullio phenomenon and a Valsalva maneuver against closed glottis causing torsional-vertical nystagmus. Temporal-bone computed tomography (CT) led to a diagnosis of right-ear SCD syndrome. Surgical dehiscence plugging with calcium phosphate cement via the middle fossa resolved vestibular and cochlear symptoms in the more than two years since.