The Natural History and Management of Petrous Apex Cholesterol Granulomas

Intraoperative imaging and navigation of the petrous apex by infralabyrinthine route

Intraoperative imaging during skull-base surgery allows the operator to control surgical dissection and to tailor the approach, reducing morbidity due to inadequate resection or reintervention. The O-arm® (Medtronic, Fridley, MN, USA) navigation system is an intraoperative cone-beam CT device that was first designed for spinal surgery but now has applications in lateral skull-base surgery. In this technical note, we present a patient with petrous apex cholesterol granuloma located medial to the intrapetrous internal carotid artery and in the infralabyrinthine compartment. We report the possibility of natural drainage, using intraoperative imaging to guide resection, through a rapid, safe and minimally invasive approach.

Radiological Classification and Management Algorithm of Petrous Apex Cholesterol Granuloma

Background: Petrous apex cholesterol granulomas (PACGs) are benign inflammatory cystic lesions of the temporal bone. Usually, asymptomatic patients may develop symptoms as the lesions expand. The diagnosis is based on both CT and MRI scans and the management relies on "wait and scan" or surgery. This paper aims at evaluating surgical outcomes and proposing a CT-based classification and a management algorithm. Methods: Patients with PACGs who were surgically treated between 2014 and 2024 were included. Symptoms, imaging, approach type and complications were considered. CT scans were classified as Type A (preserved apex cellularity), Type B (erosion of the apex cellularity), and Type C (involvement of the noble structures bone boundaries). The possible connection of the lesion with the infracochlear, perilabyrinthine and sphenoidal cellularity was assessed. Results: Nineteen patients with symptoms like diplopia, headache and sensorineural hearing loss were included. According to our classification, 1/19 patients was Type A, 4/19 were Type B and 14/19 were Type C. Five patients underwent a total resection, seven a subtotal and seven a surgical drainage. Only two complications were recorded, and 17/19 patients showed symptom regression and stability during follow-up. Conclusions: While the management of PACGs is still controversial, according to our classification and surgical outcomes, Type A, being mostly asymptomatic, should be managed with "wait and scan", Type B should undergo surgery when symptoms are present, while Type C should always undergo surgery because of their invasiveness and potential complications. When possible, a drainage should be attempted; otherwise, a surgical resection is chosen, and its completeness depends on the preoperative general and hearing status.

Surgical Approaches to Petrous Apex Cholesterol Granulomas: A Systematic Review and Network Meta-analysis

OBJECTIVE

To compare the outcomes of different surgical approaches to petrous apex cholesterol granulomas (PACG).

DATA SOURCES

PubMed, Embase, Google Scholar, Cochrane, and Web of Science.

REVIEW METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-analyses-Network Meta-analyses guidelines, databases were searched from inception to November 31, 2022. Studies comparing two or more approaches were included. Reviews and population studies were excluded. The main outcome measures were the resolution of symptoms, serviceable hearing, complication, and revision rates.

RESULTS

The search yielded 2132 studies. After applying inclusion and exclusion criteria, 15 studies remained, consisting of 214 patients treated with lateral approaches (n = 182) or anterior endonasal approaches (n = 32). The efficacy of lateral and anterior endonasal approaches in achieving symptom resolution was comparable (73% vs. 68%, p = 0.5). Both exhibited similar rates of complications (33% vs. 37%, p = 0.3), albeit with distinct profiles. Lateral approaches were associated with higher rates of facial palsy and sensorineural hearing loss (44% vs. 18%, p = 0.03). Anterior endonasal approaches demonstrated higher rates of epistaxis and cerebrospinal fluid leak (15% vs. 1%, p = 0.001). Anterior endonasal approaches exhibited lower revision rates (OR: 0.35, 95% CI: 0.14-0.88). The placement of a stent in both approaches was associated with higher symptom resolution (OR: 5.12, 95% CI: 1.05-9.97) and lower revision rates (OR: 0.71, 95% CI: 0.33-0.92).

CONCLUSIONS

Anterior endonasal approaches yield lower revision rates compared to lateral approaches for PACG. Both approaches demonstrate similar effectiveness in symptom resolution and comparable rates of complications, with distinct profiles. Facial nerve and hearing status are important factors that should be addressed when selecting the approach. Stenting is beneficial.

LEVEL OF EVIDENCE

NA Laryngoscope, 134:1540-1550, 2024.

Quantitative Evaluations of Vestibular Function in Patients With Petrous Apex Cholesterol Granulomas Treated With an Endoscopic Transsphenoidal Approach: A Report of Two Cases

OBJECTIVE

We report two cases of petrous apex cholesterol granuloma (PACG) treated with an endoscopic transsphenoidal approach. Vestibular functions of the two patients were evaluated quantitatively by video Head Impulse Test (vHIT) and/or vestibular evoked myogenic potentials (VEMPs).

PATIENTS

Two patients with PACG who experienced episodes of dizziness are presented.

INTERVENTION

An endoscopic transsphenoidal approach to PACG.

MAIN OUTCOME MEASURE

The preoperative and postoperative vestibular functions as evaluated by vHIT and VEMP.

RESULTS

Two cases of PACG were treated by a transsphenoidal approach. The internal auditory canal was compressed by the PACG in both cases. The patients both experienced episodes of dizziness before surgery and preoperative vestibular testing including vHIT and VEMP indicated dysfunction of vestibular nerves. After surgery, their symptoms were completely resolved, and the vestibular testing results were improved.

CONCLUSIONS

This article is noteworthy for being the first to publish quantitative vestibular function testing for patients with PACG with vestibular dysfunction. PACG may show various symptoms, with dizziness being one of the most common symptoms. In cases in which the internal auditory canal is compressed by the PACG, vestibular functions should be evaluated by vHIT and VEMP. In the present cases, dizziness was found to be resolved by surgery to release the compression on internal auditory canal. Based on the present cases, the transsphenoidal approach is considered to be both safe and effective.

Skull Base Tumors: The Equilibrium between Curation and Preservation

Tumors located at the skull base constitute a particular challenge for medical teams [...].

Characteristics and Clinical Management Strategy of Petrous Apex Cholesterol Granulomas

Purpose: To evaluate the clinical characteristics of petrous apex cholesterol granulomas (PACG) and assess outcomes after different treatment strategies. Method: A consecutive case series of 34 patients with a PACG. Main outcomes were PACG growth, symptoms, and the outcomes of different treatment strategies: wait-and-scan (WS) and surgical drainage. Results: Thirty-four patients were analyzed; mean follow-up time was 7.1 years. Twenty-one patients (61.7%) showed symptoms, mostly more than one. Most symptoms reported were cranial nerve palsy (58.8%) and headache (35.3%). Twenty-one patients (61.8%) received solely wait-and-scan (WS), and thirteen patients (38.2%) underwent surgery, five of whom (38.5%) after an initial WS period. In the solely WS group, one (4.8%) developed new symptoms, and two (9.5%) reported symptom progression despite a stable granuloma size. Two (9.5%) showed granuloma growth on follow-up scans without symptom progression. Surgery consisted of drainage. Eleven (84.6%) of these thirteen patients reported partial recovery; one (7.7%) reported no recovery; and one (7.7%) reported full recovery of reported symptoms related to PACG. Among the patients with cranial nerve involvement, 7.7% showed full recovery after surgery; 84.6% showed partial recovery; and 7.7% did not recover. Adverse events occurred in five out of 13 patients who underwent surgery, all with full recovery. Conclusions: This study confirms that PACG are slow-growing lesions with a low risk of adverse events. Solely using wait-and-scan strategy is a safe option for patients without symptoms, with acceptable symptoms without symptom progression, and with asymptomatic growth. Surgical treatment can be considered in patients with symptom progression or symptomatic growth.

Middle Fossa Approach for Resection of a Petrous Apex Cholesterol Granuloma: 2-Dimensional Operative Video

Cholesterol granulomas (CGs) are the most common cyst of the petrous apex.1 The management options for CG include observation and surgical resection. Surgery is complicated by the proximity of these lesions to critical neurological and vascular structures, as with many skull base lesions; however, if left untreated, their growth may lead to mass effect resulting in conductive hearing loss, cranial nerve dysfunction, tinnitus, and/or chronic headaches.2,3 In this video, we present the case of 52-year-old woman who presented with medically refractory right retro-orbital headaches. MRI revealed a large, right-sided petrous apex cystic structure consistent with a CG. Computed tomography of the head demonstrated bony remodeling. Given the large size of the cyst and the patient's symptoms, surgery was proposed, and the patient agreed. We performed a middle fossa craniotomy and elevated the dura from the floor of the middle fossa, working posteriorly from the petrous ridge and extending anteriorly. The cyst was exposed and decompressed, and its wall was then dissected off. After all cystic components were removed, the cavity was packed with abdominal fat, which is believed to prevent cyst reaccumulation. Postoperative MRI demonstrated good resection, and the patient reported complete resolution of her headaches. The patient consented to the procedure as shown in this operative video and gave informed written consent for use of her images in publication.

Typical and Atypical Symptoms of Petrous Apex Cholesterol Granuloma: Association with Radiological Findings

Objective: Petrous apex cholesterol granuloma (PACG) is a lesion that can give rise to different symptoms, and correlations with etiopathology are ambiguous. The aim of this study is to analyze the association between PACG symptoms and radiological findings at presentation, in order to establish a reproduceable pre-operative radiological evaluation and guide the surgical indication. Methods: PACG patients were collected in two tertiary care hospitals. All cases underwent CT/MRI to evaluate the cyst localization and erosion of surrounding structures. Typical and atypical symptoms were then analyzed and compared to radiologic findings established in accordance with the literature. Results: Twenty-nine patients were recruited; the most common symptoms were headache (69%), diplopia (20.7%) and fainting (24.1%), an atypical clinical manifestation related to jugular tubercle involvement. Significant associations between symptoms and radiologic findings were noted in terms of headache and temporal lobe compression (p = 0.04), fainting and jugular tubercle erosion (p < 0.001), vestibular symptoms and internal auditory canal erosion (p = 0.02), facial paresthesia and Meckel’s cave compression (p = 0.03), diplopia and Dorello canal involvement (p = 0.001), and tinnitus and cochlear basal turn erosion (p < 0.001). All patients were treated via an endoscopic−endonasal approach, in which extension was tailored to each case. At a median follow-up of 46 months, 93.1% of patients experienced resolution of symptoms. Conclusions: This clinico-radiological series demonstrates associations between symptoms and anatomical subsites involved with PACG. Hence, it may guide the surgeon at the time of surgical decision, since it asserts that typical and atypical symptoms are actually related to PACG.

Neurosurgical management of petrous bone lesions: classification system and selection of surgical approaches

BACKGROUND

Surgery of petrous bone lesions (PBLs) is challenging for neurosurgeons. Selection of the surgical approach is an important key for success. In this study, the authors present an anatomical classification for PBLs that has been used by our group for over the past 26 years. The objective of this study is to investigate the benefits and applicability of this classification.

METHODS

Between 1994 and 2019, 117 patients treated for PBLs were retrospectively reviewed. Using the V3 and arcuate eminence as reference points, the petrous bone is segmented into 3 parts: petrous apex, rhomboid, and posterior. The pathological diagnoses, selection of the operative approach, and the extent of resection (EOR) were analyzed and correlated using this classification.

RESULTS

This series included 22 facial nerve schwannomas (18.8%), 22 cholesterol granulomas (18.8%), 39 chordomas/chondrosarcomas (33.3%), 6 trigeminal schwannomas (5.1%), 13 epidermoids/dermoids (11.1%), and 15 other pathologies (12.8%). PBLs were most often involved with the petrous apex and rhomboid areas (46.2%). The extradural subtemporal approach (ESTA) was most frequently used (57.3%). Gross total resection was achieved in 58.4%. Symptomatic improvement occurred in 92 patients (78.6%). Our results demonstrated a correlation between this classification with each type of pathology (p < .001), selection of surgical approaches (p < 0.001), and EOR (p = 0.008). Chordoma/chondrosarcoma, redo operations, and lesions located medially were less likely to have total resection. Temporary complications occurred in 8 cases (6.8%), persistent morbidity in 5 cases (4.3%), and mortality in 1 case.

CONCLUSION

In this study, we proposed a simple classification of PBLs. Using landmarks on the superior petrosal surface, the petrous bone is divided into 3 parts, apex, rhomboid, and posterior. Our results demonstrated that chordoma/chondrosarcoma, redo operations, and lesions involving the tip of the petrous apex or far medial locations were more difficult to achieve total resection. This classification could help surgeons understand surgical anatomy framework, predict possible structures at risk, and select the most appropriate approach for each patient.

A review of simulation applications in temporal bone surgery

Background

Temporal bone surgery is a technically challenging and high-risk procedure in an anatomically complex area. Safe temporal bone surgery emphasizes a consummate anatomic understanding and technique development that requires the guidance of an experienced otologic surgeon and years of practice. Temporal bone simulation can augment otologic surgical training and enable rehearsal of surgical procedures.

Objectives

The purpose of this article is to provide an updated review of temporal bone simulation platforms and their uses.

Data Sources

PubMed literature search. Search terms included temporal bone, temporal bone simulation, virtual reality (VR), and presurgical planning and rehearsal.

Discussion

Various simulation platforms such as cadaveric bone, three-dimensional (3D) printed models, and VR simulation have been used for temporal bone surgery training. However, each simulation method has its drawbacks. There is a need to improve upon current simulation platforms to enhance surgical training and skills assessment, as well as a need to explore other clinically significant applications of simulation, such as preoperative planning and rehearsal, in otologic surgery.

Conclusions

There is no replacement for actual surgical experience, but high-fidelity temporal bone models such as those produced with 3D printing and computer simulation have emerged as promising tools in otolaryngologic surgery. Improvements in the fidelity of both 3D printed and VR simulators as well as integration of a standardized assessment format would allow for an expansion in the use of these simulation platforms in training and assessment.

Level of Evidence

5.

Petrous Apex Cholesterol Granulomas: Outcomes, Complications, and Hearing Results From Surgical and Wait-and-Scan Management

OBJECTIVE

1. To analyze the surgical outcomes in the management of petrous apex cholesterol granulomas (PACG) with a brief literature review.2. To evaluate the importance of wait-and-scan management option.

STUDY DESIGN

Retrospective review.

SETTING

Quaternary referral center for otology and skull base surgery.

SUBJECTS AND METHODS

Charts of 55 patients with at least 12 months of follow-up were analyzed for demographic, clinical, audiometric, and radiological features. Patients were divided into surgical group (SG) (n = 31) and wait-and-scan (n = 24) (WS) group. Surgical approach was chosen as per hearing status and PACG extension and relation to nearby neurovascular structures and included either drainage by transmastoid-infralabyrinthine approach (TM-IL)/transcanal-infracochlear approach (TC-IC) or resection by infratemporal fossa type B approach (ITF-B). The combination of ITF-B with trans-otic (TO) approach or TO approach solely was used in unserviceable hearing cases. Postoperative outcomes and complications were evaluated in SG.

RESULTS

Postoperative symptom relief was observed in 24 patients (77.4%). Diplopia and paresthesia recovered in each case and improvement in headache, dizziness, tinnitus, and hearing loss was observed in 87.1% cases. Serviceable hearing was preserved in 24 of 26 cases. Postoperative complication rate was 32.2% including incidences of profound hearing loss, facial nerve paresis, carotid artery injury and intraoperative CSF leaks. Revision surgery was required in 3 (9.6%) cases, after TM-IL approach.

CONCLUSION

Surgical drainage is preferable to more aggressive resection procedures, with the latter reserved for recurrent lesions or lesions with severe hearing loss/involvement of critical neurovascular structures. ITF-B approach provides adequate cyst and neurovascular control for resection, while avoiding brain retraction. An initial wait-and-scan approach can be used in most patients where symptoms and imaging justify so.

Endoscopic Infracochlear Approach for Drainage of Petrous Apex Cholesterol Granulomas: A Case Series

OBJECTIVE

To describe the feasibility and technical nuances of a transcanal endoscopic infracochlear approach for drainage of petrous apex cholesterol granulomas.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary care university hospital.

PATIENTS

A 32-year-old man with bilateral petrous apex cholesterol granulomas and a 54-year-old man with a left-sided petrous apex granuloma each with symptoms necessitating surgical intervention.

INTERVENTIONS

Transcanal endoscopic infracochlear approach for drainage of the cholesterol granulomas.

MAIN OUTCOME MEASURES

Operation efficacy, corridor size, and perioperative morbidity.

RESULTS

All three cholesterol granulomas were successful drained without violating the cochlea, jugular bulb, or carotid artery. The dimensions of the infracochlear surgical corridor measured 5 mm × 6 mm, 3.5 mm × 3.5 mm, and 6 mm × 4 mm, respectively. All corridors facilitated visualization within the cyst and allowed lyses of adhesions for additional cyst content eradication. All patients had resolution of their acute symptoms. Two of the three subjects had serviceable hearing before and after their procedures. One patient required revision surgery 2-months after their initial procedure secondary to recurrent symptoms from acute hemorrhage within the cyst cavity. The infracochlear tract in this patient was noted to be patent.

CONCLUSIONS

A transcanal endoscopic infracochlear approach is feasible for the management of cholesterol granuloma. The surgical access was wide enough to introduce the endoscope into the petrous apex cavity in each case. Further studies are needed to compare the efficacy and perioperative morbidity versus the traditional postauricular transtemporal approaches.

A novel drainage approach in patients with cholesterol granuloma: From petrous apex to mastoid air cell

Background:

Cholesterol granulomas (CG) of the petrous apex (CGPA) are benign lesions that have high recurrence rates after surgical intervention. We describe the use of a robust silicon drain between the petrous apex and mastoid air cells to allow constant aeration of the lesion for preventing recurrence.

Case Description:

A retrospective analysis was performed using the data of four patients treated at the Maastricht University Medical Centre between 2014 and 2016. Using the middle fossa approach, the petrous apex was reached, the cyst was opened, and the content aspirated. Subsequently, a robust silicon drain was placed between the cyst and mastoid air cell system. The outcome measures were clinical improvement of the symptoms and radiological parameters. The patients were female (n = 2) and male (n = 2) with an age range between 33 and 53 years at the time of the operation. Computed tomography and magnetic resonance imaging scans were used to confirm CG diagnosis. The most common presenting symptoms in our population were diplopia and headaches. The symptoms improved after surgery and there were no complications. Thus far, no recurrence has been observed and imaging shows aeration in the lesion area.

Conclusion:

The use of a robust drain seems to be an effective, safe, and feasible option to prevent recurrences in patients with CG.

Endoscopic Management of Middle Ear and Temporal Bone Lesions

Tantamount to the management of temporal bone neoplasms is the ability to visualize the pathology and its relationship with the numerous critical structures housed therein. Transcanal endoscopic ear surgery provides the surgeon with an unparalleled view of the entire middle ear. This article presents the latest information on the usefulness of transcanal endoscopic ear surgery in the management of middle ear and temporal bone neoplasms.

Cholesterol Granuloma Development following Temporal Bone Surgery

OBJECTIVE

To describe the clinical presentation and management of patients with cholesterol granulomas (CGs) that develop following temporal bone surgery.

STUDY DESIGN

Case series with chart review.

SETTING

Two independent tertiary academic referral centers.

SUBJECTS AND METHODS

A multicenter retrospective review was performed to identify all patients between 2001 and 2014 who were diagnosed with a CG that developed following temporal bone surgery. Patients with a history of idiopathic petrous apex CGs were excluded, as were those with <6 months of follow-up after diagnosis. Demographic and clinical data were recorded at presentation, and the main outcome measure was symptom evolution over time.

RESULTS

A total of 20 patients met inclusion criteria (median age, 55.0 years; 70.0% female), and their cases were analyzed. Diagnosis was made, on average, 149.5 months (median, 94.5; range, 13.0-480.0) following a temporal bone operation, which was for chronic ear disease in 75.0% of cases. The most common presenting symptoms were otalgia (55.0%) and otorrhea (40.0%). In patients initially managed with observation, 71.4% required no surgical intervention through a mean of 56.8 months (median, 30; range, 12.0-178.0) of follow-up. For those who initially underwent surgical excision, durable symptom relief was achieved in 66.7% of cases.

CONCLUSION

Postoperative CG formation in the temporal bone is a rare occurrence that can be encountered years following surgery. The present study suggests that conservative management can be appropriate for many cases in which patients are relatively asymptomatic.