Ventral petrous meningiomas: unique tumors

Posterior Petrous Meningiomas: Surgical Classification and Postoperative Outcomes in a Case Series of 130 Patients Operated via the Retrosigmoid Approach

OBJECTIVE

A standardized definition and classification of primary posterior petrous meningiomas (PPMs) is lacking, with consequent challenges in comparing different case series. This study aimed to provide an anatomical description and classification of PPMs analyzing a homogeneous series of patients operated via the retrosigmoid approach.

METHODS

PPMs originate laterally to the petro-occipital fissure within the venous ring composed of the superior petrosal, sigmoid, inferior petrosal, and cavernous sinuses. We proposed a classification based on tumor site of origin, direction of growth relative to the internal acoustic meatus, and cranial nerves' displacement. Four types of PPMs were defined: retromeatal (type A), meatal (type B), premeatal (type C), and broad-based (type D). We performed a retrospective analysis of 130 consecutive patients with PPMs who underwent surgery as first-line treatment.

RESULTS

The PPM classification predicted clinical presentation, postoperative morbidity, and resection rates. Headache, hydrocephalus, and cerebellar deficits were more common in type A (59.0%, 37.7%, 49.2%) and type D (66.7%, 66.7%, 33.3%). Hypoacusia/anacusia was more common in type B (87.5%), while trigeminal hypoesthesia/anesthesia was more common in type C (85.0%). After surgery, patients with type A and D PPMs were at higher risk to develop cerebellar deficits (11.5%-22.2%), whereas patients with type B and C PPMs presented with hypoacusia/anacusia (12.5%) and trigeminal deficits (10.0%), respectively. The near-total resection rate was higher in type A (91.8%), followed by types B (82.5%), C (80.0%), and D (77.8%) PPMs.

CONCLUSIONS

The PPM surgical classification has an operative and prognostic relevance. In expert hands, the retrosigmoid approach represents a safe and effective approach to remove PPMs.

Piezosurgery for safe and efficient petrous bone cutting in cerebellopontine angle and petroclival meningioma surgery

Intradural petrous bone drilling has become a widespread practice, providing extended exposure in the removal of cerebellopontine angle (CPA) or petroclival tumors. Adjacent neurovascular structures are at risk, however, when drilling is performed in this deep and narrow area. Hence, this study evaluates the use of Piezosurgery (PS) as a non-rotating tool for selective bone cutting in CPA surgery. A Piezosurgery® device was used in 36 patients who underwent microsurgery for extra-axial CPA or petroclival tumors in our Neurosurgical Department between 2013 and 2019. The clinical and radiological data were retrospectively analyzed. The use of PS was evaluated with respect to the intraoperative applicability and limitations as well as efficacy and safety of the procedure. Piezosurgical petrous bone cutting was successfully performed in the removal of meningiomas or extra-axial metastases arising from the dura of the petroclival region (21 patients) or petrous bone (15 patients). PS proved to be very helpful in the deep and narrow CPA region, considerably reducing the surgeon's distress toward bone removal in close proximity to cranial nerves and vessels in comparison to common rotating drills. The use of PS was safe without injuries to neurovascular structures. Gross total resection was achieved in 67% of petroclival and 100% of petrous bone tumors. Piezosurgery proved to be an effective and safe method for selective petrous bone cutting in CPA surgery avoiding rotating power and associated risks. This technique can particularly be recommended for bone cutting in close vicinity to critical neurovascular structures.

Differences in clinical presentation, intraoperative findings and outcome between petroclival and lateral posterior pyramid meningioma

OBJECTIVE

The goal of this study was to determine the impact of the location of the most frequent skull base meningioma of the posterior fossa, i.e. petroclival (PCM) and lateral posterior pyramid meningioma (LPPM) on clinical presentation, surgical treatment and treatment results.

PATIENTS AND METHODS

We retrospectively reviewed a consecutive series of patients operated on for PCM (n=46) and LPPM (n=32). Uni- and multivariate analyses were performed to identify differences in clinical presentation, surgical treatment and pre-, intra- and postoperative factors of influence upon the outcome parameters: Complications rate, mortality, tumour recurrence/progress, hospital stay, Karnofsky Performance Score (KPS).

RESULTS

At Presentation, the rate of dizziness was higher in LPPM (56% vs. 7%, p<0,001) and trigeminal nerve impairment was more frequent in PCM (50% vs. 3%, p<0,001). Complete tumour resections were more often achieved (91% vs. 39%, p<0,001), and surgery lasted shorter (median: 247 min vs. 500 min, p<0,001) with less blood loss (median: 525 ml vs. 1000 ml, p<0,001) in LPPM compared to PCM. The overall complication rates (73% vs. 31%, p<0,001) as well the rate of irreversible complications (57% vs. 9%, p<0,004) were higher in PCM than in LPPM. The most frequent complications of PCM surgery were eye movement (46% vs. 6%, p<0,001), facial nerve (28% vs. 3%, p<0.02) and swallowing impairments (21% vs. 3%, p<0.02). The perioperative mortality was 11% in PCM and 0% in LPPM patients. In the multivariate analyses, KPS at discharge correlate positively with age (p=0.034) and preoperative KPS (p=0.0048) in LPPM and positively with staged resection (p=0.056) and negatively with the occurrence of surgical complications (p=0,0427) in PCM. Hospitalization time correlated with the blood loss (p<0,001) for PCM, negatively with the preoperative KPS (p=0.0002) for PCM and LPPM and positively with tumour diameter (p=0.0001) and non-surgical complications rate (p=0.0001) for LPPM.

CONCLUSION

As compared to LPPM, surgical treatment of PCM is associated with higher morbidity and mortality. The outcome of LPPM was primarily influenced by preoperative factors: Patients age, tumour size, preoperative KPS. The outcome of PCM was primarily influenced by intraoperative factors like: blood loss, surgery duration, staged tumour resection and the surgical complications rate.

Endoscopic endonasal transclival approach to the jugular tubercle

BACKGROUND

The jugular tubercle is a rounded bony prominence that arises from the inferolateral margin of the clivus. In a previous publication, we described the surgical anatomy of the expanded endonasal approach to the jugular tubercle.

OBJECTIVE

To illustrate the translation of laboratory work to the operating room describing the anatomic and technical nuances of the endonasal approach to the jugular tubercle.

METHODS

We review the relevant surgical anatomy needed to perform an endonasal approach to the jugular tubercle, and we select 4 different lesions to illustrate the application of our laboratory findings.

RESULTS

In the first case, exposure and partial drilling of the jugular tubercle was critical to gain an adequate corridor to the meningioma, particularly to its inferolateral margin. This allowed for early devascularization, safe extracapsular dissection, and preservation of surrounding neurovascular structures. In addition, the jugular tubercle was hyperostotic and its resection, along with generous dural removal, provided a grade I Simpson tumor resection. In the second (chondrosarcoma) and third (chordoma) cases, the jugular tubercle was infiltrated by tumor, and consequently its complete resection was essential to achieve total tumor removal. In the last case, an unusual adrenocorticotropic hormone-secreting adenoma recurrence at the jugular tubercle region, the technical modification of the transclival approach presented here was successfully applied to achieve complete resection and Cushing disease remission.

CONCLUSION

The transjugular tubercle variant of the expanded endonasal transclival approach allows for direct access to ventrolateral lesions in the inferior clival/petroclival region with no cerebral or cerebellar retraction, or cranial nerve manipulation during the approach.