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Competing Interests: The authors disclose no conflicts of interest.

Introduction: Internal auditory canal (IAC) diverticula, also known as IAC cavitary lesions or anterior cupping of the IAC, observed in otopathologic specimens and high-resolution computed tomography (CT) scans of the temporal bone are thought to be related to otosclerosis. Herein, we examined the usefulness of CT scans in identifying diverticula and determined whether IAC diverticula are associated with otosclerosis on otopathology., Methods: One hundred five consecutive specimens were identified from the National Temporal Bone Hearing and Balance Pathology Resource Registry. Inclusion criteria included the availability of histologic slides and postmortem specimen CT scans. Exclusion criteria included cases with severe postmortem changes or lesions causing bony destruction of the IAC., Results: Ninety-seven specimens met criteria for study. Of these, 42% of the specimens were from male patients, and the average age of death was 77 years (SD = 18 yr). IAC diverticula were found in 48 specimens, of which 46% were identified in the CT scans. The mean area of the IAC diverticula was 0.34 mm 2 . The sensitivity and specificity of detecting IAC diverticula based on CT were 77% and 63%, respectively. Overall, 27% of specimens had otosclerosis. Histologic IAC diverticula were more common in specimens with otosclerosis than those without (37.5% versus 16%; p = 0.019). Cases with otosclerosis had a greater mean histologic diverticula area compared with nonotosclerosis cases (0.69 mm 2 versus 0.14 mm 2 ; p = 0.001)., Conclusion: IAC diverticula are commonly found in otopathologic specimens with varied etiologies, but larger diverticula are more likely to be associated with otosclerosis. The sensitivity and specificity of CT scans to detect IAC diverticula are limited., Competing Interests: J.C. has a patent pending at Grace Medical. E.K. is a scientific advisor at Desktop Metal and has a patent pending at Grace Medical. H.S. is in the surgical advisory board of MedEl and a shareholder at Rescue Hearing. M.J.McK. is the co-founder and CMO of Akouos Inc. A.Q. has a sponsored research agreement with Frequency Therapeutics, sponsored research agreement, patent pending at Grace Medical, and consulting for Alcon. The remaining authors disclose no conflicts of interest., (Copyright © 2022, Otology & Neurotology, Inc.)

Abstract: Petrous apex cephalocele (PAC) is a rare type of cephalocele. It is usually asymptomatic. It can be unilateral or bilateral. Bilateral cases are less common. They are etiologically and clinically different entities from unilateral ones. A 56-year-old female patient presented to the hospital with the complaint of a severe nonspecific headache. She has been examined in ear nose throat, ophthalmology, and finally neurology clinics. Bilateral PAC was incidentally found in magnetic resonance imaging (MRi) examination. Headache was associated with PAC because no additional pathology could explain the clinical symptomatology. There is a proven relationship between empty sella and PAC. Regarding PAC less than 50 cases are known. Our paper aims to contribute to the literature by exhibiting etiologic and clinic differences between unilateral and bilateral PAC. It highlights the relationship between PAC and broad sella that is a different entity from empty sella and shows this remarkable radiological appearance. The authors presented our case accompanied by clinical and MRi findings., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 by Mutaz B. Habal, MD.)

Objective: To describe the clinical course and treatment outcomes for patients with petrous apex epidermoid with skull base erosion., Study Design: Retrospective case series., Setting: Tertiary-care academic center., Patients: Patients surgically managed for petrous apex epidermoids at a single-tertiary care institution from 2001 to 2017., Interventions: Surgical management of primary petrous apex epidermoids., Main Outcome Measures: The presenting symptoms, imaging, pre- and postoperative clinical course, and complications were reviewed., Results: Seven patients were identified. The most common presenting symptoms included: sudden sensorineural hearing loss (n = 3), headaches (n = 1), vertigo (n = 2), and facial paralysis/paresis (n = 2). An epidermoid was discovered in two patients as an incidental finding after a head trauma and one patient after admission for altered mental status and meningitis. Two patients presented with complete facial paralysis (House-Brackmann 6/6). Preoperative normal hearing (pure-tone average < 25 db) was identified in three patients and serviceable hearing (pure-tone average 25-60 dB) in one patient. Three patients with nonserviceable hearing underwent a transcochlear or transotic approach. The remaining four patients underwent an attempted hearing preservation approach. Postoperatively, one patient developed delayed facial paralysis, improving within 3 months. Hearing was preserved in three patients. Two patients developed recurrence of disease within 4 and 7 years respectively., Conclusions: Surgical management of aggressive petrous apex epidermoid is effective to preserve facial function and prevent recurrence. In our series different surgical approaches were used with variable outcomes.

Backgroud: Pneumocephalus without a known underlying cause is defined as spontaneous pneumocephalus. Few patients of intraventricular pneumocephalus have been reported., Patient Presentation: An 84-year-old man presented with dysarthria and incontinence. Computed tomography revealed an intraventricular pneumocephalus, thinning in the petrous bone, fluid in the air cells, and cleft in temporal lobe. A right subtemporal extradural approach was taken to detect bone-/-dural defects, and a reconstruction was performed using a musculo-pericranial flap., Conclusion: This is the first patient of an isolated intraventricular spontaneous pneumocephalus without any other site air involved. Surgical approaches to repair such bone and dura defects should be considered an appropriate option.

Objective: Review long-term symptom-specific outcomes for petrous apex cholesterol granulomas (PACG)., Study Design: Retrospective review., Setting: Tertiary center., Patients: Adults with PACG were assessed from 1998 to 2015., Intervention(s): Symptomatic patients were stratified into surgical and observation subgroups., Main Outcome Measure(s): Resolution rates of individual symptoms and chief complaints were assessed as was the impact of surgical approach and stent usage on symptom-specific outcomes. Symptom recurrence rates were tabulated., Results: Twenty-seven patients were included whose mean age was 44.8 ± 3.3 years. Fourteen and 13 patients stratified into the surgical and observation subgroups respectively. The surgical subgroup trended toward a longer follow-up period (mean 68.5 vs. 33.8 mo; p = 0.06). Overall, the most frequent symptoms encountered were headache (52%), aural fullness, tinnitus, and vestibular complaints (41% each). Visual complaints, retro-orbital pain, and cranial neuropathies were less common (18%, 15%, 11%). The overall symptom resolution rate was significantly higher in the surgical subgroup (48% vs. 26%, p = 0.03). In both subgroups, headache, retro-orbital pain, and visual complaints had the highest resolution rates. Vestibular complaints and tinnitus were very unlikely to resolve. Significantly more patients in the surgical group resolved their chief complaints (70% vs. 25%, p = 0.02). While approach type and stent usage did not significantly influence symptom outcomes, all patients with symptom recurrence (11%) were initially managed without stents., Conclusion: Symptom-specific outcomes were better in patients managed surgically for PACG. Individual symptom resolution rates were highly variable. Some symptoms were refractory regardless of management strategy. Surgical approach and stent usage did not significantly influence symptom outcomes.

Objective: To analyze clinical outcomes after treatment of petroclival chondrosarcoma and to propose a novel staging system., Study Design: Retrospective case review, 1995 to 2015., Setting: Multicenter study., Patients: Consecutive patients with histopathologically proven petroclival chondrosarcoma., Intervention(s): Microsurgery, endoscopic endonasal surgery, radiation therapy, observation., Main Outcome Measures: Disease- and treatment-associated morbidity, recurrence, mortality., Results: Fifty-five patients (mean age 42 years; 56% women) presenting with primary or recurrent petroclival chondrosarcoma were analyzed. The mean duration of follow-up was 74 months. Among 47 primary cases, the most common presenting symptoms were headache (55%) and diplopia (49%) and the mean tumor size at diagnosis was 3.3 cm. Subtotal resection was performed in 33 (73%) patients and gross total resection in 12 (27%). Adjuvant postoperative radiation was administered in 30 (64%) cases. Preoperative cranial neuropathy improved in 13 (29%), worsened in 11 (24%), and remained stable in 21 (47%) patients; notably, 11 preoperative sixth nerve palsies resolved after treatment. Nine recurrences occurred at a mean of 42 months. The 1-, 3-, 5- and 10-year recurrence-free survival rate for all 45 patients who underwent primary microsurgery with or without adjuvant radiation therapy was 97%, 89%, 70%, and 56%, respectively. Higher tumor stage, larger categorical size (<4 versus ≥4 cm), lack of adjuvant radiation, and longer duration of follow-up were associated with greater risk of recurrence. The overall mortality rate was 2% for patients presenting with primary disease.Analyzing the cohort of 17 cases with 20 recurrences, 3 received salvage surgery alone, 5 radiation therapy alone, 11 multimodality treatment, and one patient has been observed. Tumor control was ultimately achieved in 15 of 17 patients with recurrent disease. One patient (6%) with grade 3 petroclival chondrosarcoma died as a result of rapidly progressive disease within 6 months of salvage treatment. The overall mortality rate was 6% for patients with recurrent disease., Conclusion: Gross total or subtotal resection with adjuvant radiation provides durable tumor control with minimal morbidity in most patients. Surgery may improve preoperative cranial nerve dysfunction, particularly in the case of cranial nerve 6 paralysis.

Objective: To determine how classification of petrous bone cholesteatomas (PBCs) using the 5-point Sanna classification can predict major structural involvement, facial nerve outcomes, hearing outcomes, postoperative complications, and disease recurrence., Study Design: Retrospective case series., Setting: Tertiary referral center in Bergamo, Italy., Patients: Eighty-one sequential patients with radiologic and surgically confirmed diagnoses of PBC treated at a single tertiary referral center during a 20-year period., Main Outcome Measures: Major structural involvement, facial nerve outcomes, hearing outcomes, postoperative cerebrospinal fluid leak, and disease recurrence were evaluated on the basis of Sanna classification., Results: Using the Sanna classification, 70% (57) were supralabyrinthine, 12% (10) infralabyrinthine, 7% (6) infralabyrinthine-apical, 5% (4) apical, and 5% (4) massive. Massive classification was statistically significantly associated with cochlear involvement (p = 0.009) and internal auditory canal involvement (p = 0.02). The infralabyrinthine-apical class was associated with carotid canal involvement (p = 0.03). Facial nerve interruption was observed in 35% of patients and most frequently in the apical group (75%). Neither hearing nor facial nerve outcomes were associated with Sanna classification. House-Brackmann score improved or was maintained postoperatively in 89% of patients., Conclusion: The Sanna classification provides anatomic detail on location of PBCs and is predictive of IAC, cochlear, and carotid artery involvement. However, classification systems for this rare condition continue to pose a challenge in being able to accurately predict facial nerve and hearing outcomes in surgical obliteration of PBC.

Objective: To evaluate the clinical and radiographic characteristics of cholesterol granulomas of the petrous apex, as well as the outcomes of operative and conservative management., Study Design: Retrospective chart review., Setting: Two independent tertiary academic referral centers., Patients: Adult and pediatric patients with cholesterol granulomas of the petrous apex were identified from the experience of two separate centers. Patients were included after radiographic diagnosis and clinical evaluation. All patients with less than 6 months of follow-up and those with iatrogenic postoperative cholesterol granulomas were excluded., Intervention: Demographic information, presenting symptoms, imaging characteristics, treatment strategies, and outcomes were recorded., Main Outcome Measures: Patients were evaluated on the basis of symptom and radiographic evolution during time, with or without operative intervention., Results: Ninety petrous apex cholesterol granulomas were analyzed (57.8% females, 55.6% right-sided). The average age at presentation was 43.1 years (median 42.0, range 8.0-77.0 years). The most common presenting symptom was headache (56.7%), and the average lesion size in the greatest dimension was 2.1 cm (median 1.7, range 0.7-5.0 cm). During a mean follow-up of 46.0 months, no cases of spontaneous rupture or carotid injury occurred. Twenty-three patients (25.6%) ultimately underwent surgical management, most commonly for intractable headache, and only 47.8% of these patients experienced durable symptom improvement by their last postoperative follow-up., Conclusion: Many cholesterol granulomas of the petrous apex remain stable during time and can be safely managed with primary observation. Surgery should be reserved for lesions that are causing, or threatening, neurologic dysfunction because of mass effect or erosion of critical structures such as the otic capsule. Cranial neuropathy associated with cholesterol granuloma may improve after operative management; however, symptoms such as headache and dizziness are less likely to benefit from surgery. As a general guideline, in the presence of a radiologically stable cholesterol granuloma in the petrous apex, alternative etiologies for headache and dizziness should be considered and treated before offering surgical intervention.

Background: Previous studies have shown that open cranial vault remodeling does not fully address the endocranial deformity. This study aims to compare endoscopic-assisted suturectomy with postoperative molding helmet therapy to traditional open reconstruction by quantifying changes in cranial base morphology and posterior cranial vault asymmetry., Methods: Anthropometric measurements were made on pre- and 1-year postoperative three-dimensionally reconstructed computed tomography scans of 12 patients with unilateral lambdoid synostosis (8 open and 4 endoscopic-assisted). Cranial base asymmetry was analyzed using: posterior fossa deflection angle (PFA), petrous ridge angle (PRA), mastoid cant angle (MCA), and vertical and anterior-posterior (A-P) displacement of external acoustic meatus (EAM). Posterior cranial vault asymmetry was quantified by volumetric analysis., Results: Preoperatively, patients in the open and endoscopic groups were statistically equivalent in PFA, PRA, MCA, and A-P EAM displacement. At 1 year postoperatively, open and endoscopic patients were statistically equivalent in all measures. Mean postoperative PFA for the open and endoscopic groups was 6.6 and 6.4 degrees, PRA asymmetry was 6.4 and 7.6%, MCA was 4.0 and 3.2 degrees, vertical EAM displacement was -2.3 and -2.3 millimeters, and A-P EAM displacement was 6.8 and 7.8 millimeters, respectively. Mean volume asymmetry was significantly improved in both open and endoscopic groups, with no difference in postoperative asymmetry between the 2 groups (P = 0.934)., Conclusions: Patients treated with both open and endoscopic repair of lambdoid synostosis show persistent cranial base and posterior cranial vault asymmetry. The results of endoscopic-assisted suturectomy with postoperative molding helmet therapy are similar to those of open calvarial vault reconstruction.

Although facial asymmetry in hemifacial microsomia (HFM) is well documented in the literature, no studies have concentrated on the morphology of the cranial base. This study aimed to evaluate the endocranial morphology in patients with HFM. Consecutive patients with unilateral HFM treated at a craniofacial center from 2000 to 2012 were included. The patients were grouped according to severity on the basis of the Kaban-Pruzansky classification: mild (0-1), moderate (2a), and severe (2b-3). Skull base angulation and transverse craniometric measures were recorded and then compared with those of age-matched controls. A total of 30 patients (14 males, 16 females) averaging 7.5 years of age (range, 1.1-15.7 y) were included. Four patients were classified as mild; 12, as moderate; and 14, as severe. The mean cranial base angle was found to be between 179 and 181 degrees with no significant difference between the severity groups (P = 0.57). The mean cranial base angle did not differ significantly in the patients compared with the controls(179.6 vs 180.0; P = 0.51) No significant differences between the affected and unaffected sides in the patients were found in distances from the midline to hypoglossal canal, internal acoustic meatus, lateral carotid canal, medial carotid canal, foramen ovale, and rotundum. There were no significant differences in transverse measurements between the severity classes using the same landmarks (P = 0.46, P = 0.30, P = 0.40, P = 0.25, P = 0.57, and P = 0.76, respectively). The cranial base axis is not deviated in the patients with HFM compared with the age-matched controls, and there exists little difference in endocranial morphologic measurements with increasing severity of HFM. These data are interesting, given the role of the cranial base in facial growth and the varying hypotheses regarding the mechanism of disease in HFM.

Objective: To discuss the differential diagnosis of petrous ridge lesions based on a rare case of metastatic pituitary carcinoma., Patient: A 41-year-old man with a past medical history of pituitary adenoma and hypopituitarism presented with imbalance and vertigo. Imaging showed a mass eroding the left posterior petrous face., Intervention: Transtemporal, transmastoid approach for complete resection of tumor., Main Outcome Measures: Surgical pathology and imaging studies., Results: Surgical pathology revealed metastatic pituitary carcinoma. The patient has been followed at our institution for 28 months postoperatively without evidence of recurrence., Conclusion: Lesions of the petrous ridge are rare. The wide differential diagnosis includes endolympatic sac tumor, meningioma, jugulotympanic paraganglioma, myeloma, and metastasis. The clinician must take into account unique imaging features on CT and MRI, and final diagnosis often requires pathologic analysis.

Objective: In this case report, we present a novel, minimally invasive image-guided approach to drainage of a petrous apex lesion., Patient(s): A 34-year-old man diagnosed with a petrous apex lesion consistent with cholesterol granuloma. The granuloma was large and caused mild compression of the brainstem with associated neurologic symptoms and seizure-like activity., Interventions: Based on the anatomic location of the lesion, it was determined that the treatment plan would be to surgically drain the lesion via 2 linear paths-one after an infralabyrinthine approach and the other a subarcuate approach. Customized microstereotactic frames that mount on bone-implanted markers and constrain the drill along the desired path were used to accurately drill these desired paths and avoid damage to surrounding critical structures. After a simple mastoidectomy, the petrous apex was successfully reached without damage to vital adjacent structures by drilling the 2 linear channels using 2 custom microstereotactic frames., Main Outcome Measures: Viscous brown liquid and debris was recovered by irrigating through one of the channels and suctioning through the other., Results: Drainage of the petrous apex was successfully performed via 2 linear channels without any complications. Custom microstereotactic frames were used to accurately drill those linear channels. Postoperative CT ensured no complications. Postoperative course of the patient was remarkable with normal hearing and normal facial nerve function., Conclusion: We presented a successful implementation of an image-guided approach to drain petrous apex.

Objective: There is ongoing debate on the pathogenic mechanisms of cholesterol granuloma formation in the temporal bone. The purpose of this report is to provide evidence in support of the exposed marrow hypothesis in explaining the pathogenesis of petrous apex cholesterol granuloma., Study Design: Retrospective single case study., Main Outcome Measurement: The primary outcome evaluated was the diagnosis of a new cholesterol granuloma in a petrous apex that previously demonstrated radiologic evidence of bone marrow exposed to petrous apex air cells., Results: A patient with a unilateral petrous apex cholesterol granuloma develops a new, contralateral cholesterol granuloma in a hyperpneumatized temporal bone petrous apex shown previously to have medullary bone exposed to air cells., Conclusion: This report implicates the medullary-air cell interface in a hyperaerated temporal bone petrous apex in the development and growth of a petrous apex cholesterol granuloma.

Our objective was to evaluate the relationship between subjective pulsatile tinnitus and petrous bone pneumatization. Twenty-five patients admitted between January 2012 and March 2012 were assessed. The control group data were obtained by assessment of petrous bone images of 25 cases in which paranasal sinus computed tomography (CT) was performed because of chronic sinusitis and in which no ear pathology was present. Temporal bone CT images of patients with subjective pulsatile tinnitus were compared with those of patients with no ear complaints. The presence of petrous bone pneumatization was evaluated by CT. Subjective pulsatile tinnitus complaints were present for 32 of 50 ears. Pneumatization was detected in the petrous bone of 22 (68.8%) of 32 ears with subjective pulsatile tinnitus. In the control group, 25 patients (50 ears) with no ear complaints were assessed. Petrous bone pneumatization was detected in 12 (24%) of 50 ears comprising the control group. There was a statistically significant difference between the 2 groups (P = 0.000 < 0.001). Petrous bone pneumatization might be the cause of the subjective pulsatile tinnitus.

Objective: This study presents our experience with a series of patients suffering from petrous bone fractures violating the otic capsule who underwent subtotal petrosectomy combined with eustachian tube, middle ear, and mastoid obliteration, with the goal of preventing cerebrospinal fluid (CSF) leak and meningitis., Methods: This study enrolled 26 patients between 1997 and 2011. The clinical symptoms, otoscopy, and preoperative and postoperative audiometry and facial function, as well as CSF leak or meningitis, were evaluated in each patient. The entire group underwent a subtotal petrosectomy using the technique described in detail by Fisch. In addition, each patient was interviewed using a questionnaire to evaluate the impact on quality of life., Results: Intraoperatively, we found significant CSF leaks in 14 patients (42.5%). No patient reported other episodes of CSF leak or meningitis after the surgery. The patients' responses of facial nerve function were slightly worse than the House-Brackmann evaluation (50% versus 42.3%; p < 0.05). The vast majority (88.5%) of the patients experienced no social impact., Conclusion: Our findings suggest the importance of not underestimating the risk for CSF leak in the petrous bone fractures violating the otic capsule. Preoperative counseling regarding the various troublesome complications must adequately motivate candidates to undergo surgery by pointing out the positive impact of the proposed treatment.

Objectives: (1) To assess the maintenance of drainage pathway patency in patients who undergo surgical management of cholesterol granulomas, (2) to review the histopathologic and radiologic changes associated with surgical drainage of petrous apex (PA) cholesterol granulomas, and (3) to provide histopathologic evidence regarding the exposed marrow theory of PA cholesterol granulomas., Study Design: Retrospective case review and histopathologic analysis., Setting: Tertiary referral center., Patients: Records of 17 patients with surgically managed PA cholesterol granulomas were reviewed. Histopathologic analysis was performed on temporal bones of 11 patients with PA cholesterol granulomas from the Temporal Bone repository at the House Research Institute., Interventions: Surgical drainage of PA cholesterol granulomas; follow-up radiologic imaging (computed tomography or magnetic resonance imaging), when available., Main Outcome Measures: Primary outcome is demonstrated maintenance of a PA outflow drainage pathway after the surgical drainage procedure as assessed by radiologic imaging, available histopathology, and/or recurrence of symptoms indicating failure of maintenance. Other measures include need for revision surgery and histopathology findings., Results: A majority (65%) of patients exhibited maintenance of their PA drainage pathway. Histopathologic evidence suggests that the PA drainage pathway can be maintained for many years after surgical drainage. Recurrence of symptoms was related to obstruction of the drainage pathway by fibrous tissue and/or granulomatous tissue. Placement of a stent improved the patient's chance of remaining symptom-free, with recurrence of symptoms and revision surgery required in only 2 stent cases (18%) as compared with 83% of those with no stent (p ≤ 0.035). Histopathologic evidence for the exposed marrow theory of PA cholesterol granulomas was found., Conclusion: The majority of patients who undergo surgical drainage of PA cholesterol granulomas remain symptom-free after surgical drainage. Histopathologic analysis of temporal bone specimens provides evidence supporting the exposed marrow theory of PA cholesterol granuloma formation. Loss of patency of the PA drainage pathway may be an important predictor for symptomatic recurrence of PA cholesterol granulomas. Placement of a stent may decrease the likelihood of symptomatic recurrence.

Objective: The temporal bone shields sensorineural, nervous, and vascular structures explaining the potential severity and complications of trauma related to road and sport accidents. So far, no clear data are available on the exact mechanisms involved for fracture processes. Modelization of structures helps to answer these concerns. Our objective was to design a finite element model of the petrous bone structure to modelize temporal bone fracture propagation in a scenario of lateral impact., Materials and Methods: A finite element model of the petrous bone structure was designed based on computed tomography data. A 7-m/s lateral impact was simulated to reproduce a typical lateral trauma. Results of model analysis was based on force recorded, stress level on bone structure up to induce a solution of continuity of the bony structure., Results: Model simulation showed that bone fractures follow the main axes of the petrous bone and occurred in a 2-step process: first, a crush, and second, a massive fissuration of the petrous bone. The lines of fracture obtained by simulation of a lateral impact converge toward the middle ear region. This longitudinal fracture is located at the mastoid-petrous pyramid junction., Discussion: Using this model, it was possible to map petrous bone fractures including fracture chronology and areas of fusion of the middle ear region. This technique may represent a first step to investigate the pathophysiology of the petrous bone fractures, aiming to define prognostic criteria for patients' care.

Objective: To describe the clinical course, diagnostic features and management of a case of reversible posterior leukoencephalopathy syndrome after a lateral cranial base removal., Patient: A 58-year-old male patient with an inconspicuous clinical history presented with a lethargic state without localized neurologic deficit in the postoperative period of a subtotal petrosectomy for an adenoid cystic carcinoma of the temporal bone., Interventions: Cranial T2-weighted magnetic resonance imaging showed increased signal intensity in the occipital and cerebellar regions, centered at the cortical and subcortical white matter. Antihypertensive drugs, anticonvulsants, and antibiotics were administered. A complete resolution of the symptoms and radiologic findings were achieved within 1 to 2 weeks., Results: The clinical presentation, radiologic findings, and resolution of the clinical setting are consistent with a diagnosis of reversible posterior leukoencephalopathy syndrome., Conclusion: To our knowledge, this is the first report of reversible posterior leukoencephalopathy syndrome after a lateral cranial base surgery.

Background: Earlier investigations suggest that the morphologic features of patients with lambdoid synostosis include ipsilateral occipital flattening, an ipsilateral mastoid prominence, downward cant of the posterior skull base to the affected side, and contralateral hemifacial deficiency. These features are absent in patients with deformational plagiocephaly. The authors hypothesize that significant differences in craniofacial morphology exist between patients with lambdoid synostosis and those with deformational plagiocephaly., Methods: Craniometric measurements were performed on patients with unilateral lambdoid synostosis (n = 9) and deformational plagiocephaly (n = 12). Measurements were performed on affected and unaffected sides and included posterior fossa deflection angle, petrous ridge angle, middle cranial fossa and anterior cranial fossa area, temporomandibular joint displacement, and maxillary and mandibular dimensions. Appropriate statistical tests were performed., Results: Statistically significant differences in posterior fossa deflection angle, petrous ridge angle, and middle cranial fossa were found between groups. Lambdoid synostosis patients demonstrated a larger petrous ridge angle (p = 0.0001) and middle cranial fossa (p = 3.37 × 10(-6)) on the unaffected side. Deformational plagiocephaly patients exhibited no discrepancies between sides. The mean posterior fossa deflection angle was 10.55 degrees for the lambdoid synostosis group and 3.59 degrees for the deformational plagiocephaly group (p < 0.0001). All lambdoid synostosis patients had deviation of the posterior cranial fossa toward the affected side. Deformational plagiocephaly patients had variable deflection. All lambdoid synostosis patients demonstrated marked posterior displacement of the contralateral temporomandibular joint. Deformational plagiocephaly patients had either symmetric temporomandibular joint position (75 percent) or slight contralateral posterior displacement (25 percent). Mandibular size was not significantly different between groups., Conclusion: Patients with lambdoid synostosis and deformational plagiocephaly manifest significant differences in cranial base morphology, contributing to the phenotypic differences seen in these two groups of patients.

Objective: To describe the clinical course, diagnostic features, and treatment of a case of Gorham-Stout syndrome involving the petrous apex and causing chronic cerebrospinal fluid (CSF) leak., Study Design: Clinical capsule report., Setting: Academic pediatric hospital., Patient: A 12-year-old boy presented with a destructive lesion of the right petrous apex and a 1-month history of headache, nausea, and vomiting., Interventions: Computed tomographic and magnetic resonance imaging revealed a nonenhancing lytic lesion of the right petrous apex and mandibular condyle. The lesions were bright on T2-weighted imaging with high signal intensity extending into the surrounding soft tissues. Leptomeningeal enhancement and an opening pressure of 0 cm of water on lumbar puncture suggested chronic CSF hypotension. Initial surgical exploration revealed diffuse infiltration of CSF into the soft tissue lateral to the temporal bone. Subsequent middle ear and mastoid obliteration was performed to definitely repair the CSF leak., Results: The clinical presentation, physical, laboratory, radiologic, and operative findings are consistent with a diagnosis of Gorham-Stout syndrome. In this case, lymphangiomatosis led to massive osteolysis of the petrous apex with CSF fistula into the surrounding soft tissues and middle ear with chronic intracranial hypotension., Conclusion: This is the second report of chronic CSF leak resulting from lymphangiomatosis of the cranial base (Gorham-Stout syndrome).

A 12-year-old boy developed fever, trigeminal pain, altered mental status, and a sixth cranial nerve palsy, features of Gradenigo syndrome. Diffusion-weighted MRI demonstrated restricted diffusion in the ipsilateral petrous apex, identifying an abscess as the cause of his manifestations. The patient was successfully treated with broad-spectrum antibiotics. This is the first report demonstrating the use of diffusion-weighted imaging in Gradenigo syndrome.

Hypothesis: Development of the osseous petrous carotid canal is frequently incomplete., Background: Although dehiscence of the carotid canal has been observed in previous studies, the frequency and extent of bony dehiscence have not been quantified. Inadvertent internal carotid artery injury occurs in 3 to 5% of skull base procedures, with an additional 1.9% of patients having carotid artery vasospasm. Documentation of the incidence of petrous apex carotid canal dehiscence is therefore warranted., Methods: Ninety-nine cadaveric skulls were evaluated physically and by computed tomographic scan., Results: Incidence of dorsal (endocranial) dehiscence of the petrous carotid canal was identified in 82.83% of the left side and 88.89% of the right side. Average dimensions for left dorsal dehiscence measured 10.81 mm longitudinally by 4.10 mm transversely. Dimensions for the right averaged 11.59 mm longitudinally by 4.29 mm transversely. Incidence of ventral (exocranial) dehiscence was less frequent: 37.37% on the left and 34.34% on the right. Ventral dehiscence was classified into major (absence of bone) and minor (fissure) types. Major dehiscence was observed in 8.08% and 6.06% of specimens for left and right sides, respectively; minor ventral dehiscence was present in 29.29% and 28.28% for left and right sides, respectively., Conclusion: Dorsal petrous carotid canal dehiscence is more common than previously recognized. Dehiscence of the dorsal carotid canal is a frequent finding with significant implications in advanced skull base approaches to the petrous apex, clivus, and lateral sellar compartment. Ventral dehiscence is a frequent finding that will become increasingly relevant as the scope of endoscopic skull base procedures.

Objective: To report 4 patients who have developed a conductive and/or mixed hearing loss due to dehiscence of the inner ear after retrosigmoid approach for removal of acoustic neuroma., Patients: Four patients who presented with conductive and/or mixed hearing loss after retrosigmoid approach for removal of acoustic neuroma., Main Outcome Measure: Evidence of inner ear dehiscence on postoperative computed tomographic scan of the temporal bones., Conclusion: The occurrence of conductive hearing loss after the surgical removal of an acoustic neuroma has not previously been documented. Computed tomographic scan of the temporal bones showing inner ear dehiscence may explain this finding. Formal documentation of such cases may allow techniques to be developed to reduce its occurrence or reconstruction of the defect at the time of primary surgery.

Objective: To review our series of 51 patients with transcranial petrous apex tumors who were surgically managed through a preauricular subtemporal approach., Study Design: A retrospective analysis of patient medical records., Setting: Tertiary care academic medical center., Patients: All patients with transcranial petrous apex tumors who were surgically treated between July 1988 and July 2005 with a preauricular subtemporal approach., Intervention: The preauricular subtemporal approach with preservation of hearing was used in all 51 cases., Main Outcome Measures: The degree of tumor resection and long-term results., Results: Total tumor resection was achieved in 45 patients, and tumor was left in the cavernous sinus in 6 cases. Magnetic resonance imaging surveillance revealed no recurrent tumor in 36 patients, stable residual disease in 5 cases, and regrowth of tumor in 10 individuals (mean follow-up, 8.8 yr)., Discussion: The postauricular infratemporal fossa approach allows adequate exposure to the petrous apex but with the expense of conductive hearing deficit. The preauricular subtemporal approach allows wide access for transcranial petrous apex tumors with preservation of hearing. Tumor control using this approach was achieved in 41 (80%) of 51 of the patients in this series.

Objective: Presentation of the clinical features of 2 very rare middle ear tumors in which the guiding symptom was facial palsy., Material and Methods: Illustrative case reports about a myxoma and a carcinoid tumor of the middle ear associated with peripheral facial palsy., Results: The facial palsy was transient in either case, and its pathomechanism is open for discussion. In both cases, the initial symptoms were typical for an inflammatory process. Moreover, both tumor entities are typically found in organs other than the ear; if located in the middle ear, those neoplasms grow rather superficially. In those cases, a surgical exposure of the middle ear is indicated., Conclusion: The etiopathology of an acute peripheral facial palsy is often hard to identify. If the facial weakness starts together with symptoms suggesting an inflammatory process, the differential diagnosis may be focused first on diseases like herpes zoster oticus and a severe course of acute purulent otitis media. We report the cases of 2 rare middle ear tumors causing facial palsy. Treatment of choice should be complete surgical excision.

Objective: The objective of the present study was to report our surgical strategy in the management of 81 patients with posterior petrous face meningiomas., Study Design: Retrospective study., Setting: This study was conducted at a quaternary private otology and cranial base center., Patients: Of 139 patients with posterior fossa meningioma, 81 occurred on the posterior petrous face of the temporal bone and were the object of this study., Interventions: Thirty-one patients were approached by the enlarged translabyrinthine approach. The enlarged translabyrinthine approach with transapical extension Type II was performedin 29 patients. The combined retrosigmoid-retrolabyrinthine approach was chosen in 8 cases. The modified transcochlear approach Type A with permanent posterior transposition of the facial nerve (FN) was performed in 6 patients. Two patients underwent a retrolabyrinthine subtemporal transapical approach. One patient underwent a transpetrous middle cranial fossa approach. Four patients with intracanalicular meningiomas were operated on through the enlarged middle cranial fossa approach., Results: Total removal of the tumor (Simpson Grades I and II) was achieved in most patients (92.5%). The FN was anatomically preserved in 79 of the 81 (97.5%) patients. Five patients had less than 1 year follow-up, and 2 patients were lost to follow-up and were excluded in evaluation of the final FN outcome. At 1-year follow-up, 46 patients (63%) had Grade I to II, 19 (26%) had Grade III, 4 (5.4%) had Grade IV, 1 (1.3%) had Grade V, and 3 (4.1%) had Grade VI. Hearing-preserving surgery was attempted in 15 patients (18.5%) with preoperative serviceable hearing. Of these 15 patients, 11 had their hearing preserved at the same preoperative level, and 4 experienced postoperative deafness. Postoperatively, a new deficit of 1 or more of the lower cranial nerves was recorded in 3 patients. One patient experienced subcutaneous cerebrospinal fluid collection that required surgical management., Conclusion: Total tumor removal (Simpson Grades I-II) remains our treatment of choice and takes priority over hearing preservation. Subtotal resection is indicated for older and debilitated patients with giant lesions to relieve the tumor compression on the cerebellum and brainstem. Subtotal removal is also preferred in the face of the absence of a plane of cleavage between the tumor and the brainstem, in the presence of encasement of vital neurovascular structures, in elderly patients with tumors adherent to preoperatively normal facial or lower cranial nerves.

Objective: To investigate and compare the usefulness of preoperative magnetic resonance (MR) imaging and high-resolution temporal bone computed tomography (HRCT) in pediatric cochlear implant candidates., Study Design: Prospective., Setting: Tertiary referral center., Patients: A cohort of 92 pediatric patients with profound hearing. Inclusion criteria were MR, computed tomography, and cochlear implantation. INTERVENTION., Diagnostic: All patients had preoperative imaging of the petrous temporal bone (HRCT, T2-weighted fast spin echo, axial 3D Fast Imaging Employing Steady-state Acquisition [FIESTA] MR) and brain (Fast Fluid-attenuated Inversion-recovery [FLAIR] MR)., Main Outcome Measure(s): Overall prevalence of inner ear dysplasias in this population and comparison of detection rates between HRCT, T2 Fast Spin Echo (FSE), and FIESTA MR sequences., Results: Radiological abnormalities were observed in 32 and 59% of MR and HRCT temporal bone, respectively. Synchronous intracranial findings were noted in 40% on brain MR. Common vestibulocochlear nerve was observed in 3% ears and directed side of implantation. Consistent discrepancies noted on HRCT were inability to diagnose early obliterative labyrinthitis and presence of the cochlear nerve in the internal auditory canal. With respect to MR, enlarged vestibular aqueducts and narrow cochlear nerve canals were consistently under identified., Conclusion: Dual-modality imaging with HRCT and MR of petrous bone and MR brain in the precochlear implant pediatric population detects abnormalities related to deafness, which would not otherwise be found using either modality alone. There is overlap between the imaging modalities in the type of abnormalities detected, and we present a case for selective use of HRCT within a diagnostic algorithm, using the patient risk factors we have identified.

Objective: To describe the presentation, diagnostic evaluation, and surgical management of petrous apex cerebrospinal fluid (CSF) cysts and cephaloceles., Study Design: Retrospective case review., Setting: Tertiary referral center., Patients: Six patients with symptomatic CSF cysts or cephaloceles., Intervention(s): All patients underwent operative intervention., Main Outcome Measure(s): Presentation, imaging characteristics, operative findings, surgical approach, resolution of symptoms, and complications., Results: Six patients presented with various neurotologic symptoms including vertigo, otalgia, diplopia, meningitis, hearing loss, and retroorbital headaches. Four lesions were centered within the anterior petrous apex and were classified as a cephalocele originating from Meckel's cave. The remaining two lesions were arachnoid cysts that involved the posterior petrous apex. Cysts and cephaloceles both demonstrated bone erosion on computed tomography and were hyperintense on T2-weighted magnetic resonance imaging and isointense or hypointense on T1-weighted magnetic resonance imaging. A variety of surgical approaches was used to treat these lesions. Preoperative symptoms were improved in five of six cases. One patient developed a postoperative CSF leak that resolved with conservative measures., Conclusion: Petrous apex CSF cysts and cephaloceles may present with a variety of neurotologic symptoms. Imaging often helps narrow the differential diagnosis, but these lesions can still be confused with other erosive skull base lesions such as cholesterol granulomas, epidermoids, or tumors. Optimal treatment of symptomatic posterior petrous apex CSF cysts is marsupialization via a posterior fossa approach (i.e., retrosigmoid or retrolabyrinthine). A middle fossa approach with obliteration of the anterior petrous apex may be used to treat symptomatic CSF cephaloceles arising from Meckel's cave.

Objective: Petrous apicitis and cranial base osteomyelitis are life-threatening conditions. A surgical management may be necessary in cases that progress, in conditions that fail to improve with medical treatment, or in cases with impending complications. In this study, we describe a technique to remove the maximum amount of infected temporal bone while preserving the integrity of the peripheral auditory pathway and facial nerve., Study Design: Retrospective study., Setting: Tertiary referral hospital., Patients: Five patients with impending complications, whose disease progressed or whose conditions failed to improve while on culture-directed antibiotics underwent circumferential petrosectomy., Interventions: The circumferential petrosectomy removes most of the temporal bone around the external, middle, and inner ear. A combined retrolabyrinthine-apical petrosectomy is performed in conjunction with the fallopian bridge technique using a transmastoid and middle cranial fossa approach. A split temporalis muscle flap is used to bring vascularized tissue to the mastoid, jugular foramen, and petrous apex., Main Outcome Measures: Disease resolution, change in hearing or facial nerve function, complications., Results: Each of the five patients had modifications to the procedure tailored to their disease extent: three had disease primarily involving the petrous apex and two had disease adjacent to the jugular foramen. Additional cultures of the infected bone were obtained during surgery. A culture-directed antibiotic therapy (duration, 6-10 weeks) was administered after surgery, which resulted in the complete resolution of the disease and the associated symptoms in all five patients. No patient experienced hearing loss or facial nerve dysfunction as a result of the surgery within at least 1 year of follow-up in four of the five patients in this series., Conclusion: The circumferential petrosectomy is a potential treatment option when medical treatment fails in patients with petrositis or cranial base osteomyelitis. It permits maximal temporal bone debridement while preserving hearing and facial nerve integrity in these life-threatening disease processes.

Giant cell tumor (GCT) is an uncommon primary bone tumor. The GCT mostly involves the extremity long bones. Rare is a GCT with tumoral growth in the cranium, especially other than the sphenoid bone. We herein report a 31-year-old male patient presenting with ipsilateral hearing loss and episodes of vertigo due to a large lobulated GCT of the right petrous temporal bone extending into the contiguous middle cranial fossa, infratemporal space, middle ear and external ear canal. He was treated with a macroscopically radical tumor excision followed by conventional megavoltage radiotherapy. The patient remains free of clinical and radiological evidences of tumoral recurrence six years after treatment. This experience supports the rationale for the combined treatment with radical excision plus irradiation toward this rare neoplasm when vigorous invasion of the skull base is encountered.

Objective: To highlight a case of cochlear implantation in the setting of ipsilateral petrous apex chondrosarcoma., Background: A patient with bilateral progressive hearing loss was incidentally found to have a destructive right petrous apex lesion on computed tomography before cochlear implantation. The patient had no associated symptoms and a magnetic resonance imaging scan was obtained, narrowing the differential diagnosis. A middle cranial fossa approach was performed for synchronous biopsy of the lesion and cochlear implantation., Results: Frozen sections revealed a low-grade chondroid lesion, and a Med-El Combi 40+ cochlear implant with a split electrode array was inserted via the middle fossa. Final pathologic examination revealed a Grade I chondrosarcoma. The patient suffered no complications postoperatively and was followed-up over 5 years with serial computed tomographic scans and clinical examinations. No additional treatment was administered. Eighteen months postoperatively, the patient experienced episodic vertigo. There were no new findings on computed tomography, and the vertigo improved with a low-salt diet. Otherwise, the patient had excellent hearing results, and the lesion has not progressed under observation., Conclusion: The implications of observing low-grade chondrosarcomas in well-selected patients and the unique aspect of cochlear implantation on the affected side are discussed.