Peritumoral Edema Is Associated With Postoperative Hemorrhage and Reoperation Following Vestibular Schwannoma Surgery

Unexpected Complications Following Accidental Petrosal Vein Damage during Standard Retrosigmoid Surgery for a Large Vestibular Schwannoma: Introspection and Lessons Learned

We present the case of a patient with a vestibular schwannoma (VS) who developed vascular complications following surgery and discuss the potential mechanisms. Additionally, we systematically searched the literature to identify citations on vascular and brain stem complications following VS surgery. We excluded the articles related to facial and vestibulocochlear nerve-related complications and other complications, such as headache, tinnitus, and ataxia. We also excluded the articles related to recurrent vestibular schwannoma because our article focuses on primary VS surgery-related complications due to vascular injury. We have clearly come a long way in managing vestibular schwannoma (VS) surgery over the past century. In the early twentieth century, VS surgery entailed high morbidity and mortality. The principles of microneurosurgery have improved the outcomes of surgery on VSs to a great extent. The current concept in modern VS surgery is maximal safe resection with minimal complications and minimal cranial nerve deficits. The management of VS has undergone a paradigm shift from reducing mortality to facial nerve preservation and the preservation of hearing. Surgery of the cerebellopontine (CP) angle requires a unique skill set and is a craft in that any iatrogenic damage can have devastating results on the neurovascular structures and brain stem in the vicinity. As with other neurosurgical procedures, the goal of VS surgery is to minimize complications, but complications are always possible, from the positioning of the patient under general anaesthesia to complications during the various steps of VS surgery. In spite of advancements in surgical techniques and better illumination provided by modern high-end microscopes, the surgical removal of large and giant vestibular schwannomas with good preservation of facial nerve function continues to be one of the most challenging operations in modern neurosurgery. The complexity of operating on the vestibular schwannoma is attributable not only to the difficult anatomy in the CP angle but also to the presence of multiple vital neurovascular structures and the brain stem in the vicinity. The various complications arising out of surgery for vestibular schwannomas range from one or more cranial nerve deficits to life-endangering complications associated with vascular and/or brain stem damage. The senior author, who has a personal experience with consecutively operating on 835 such cases of large and giant vestibular schwannoma, describes the clinical course following petrosal vein damage to a patient who underwent a standard retrosigmoid operation for a large vestibular schwannoma. We retrospectively analyse the critical management issues that could have reduced the unexpected morbidity resulting in a prolonged hospital stay.

Hemorrhagic Risk in Vestibular Schwannoma Surgeries: Insights and Implications

BACKGROUND Vestibular schwannoma is a slow-growing benign tumor arising from the 8th cranial nerve. It can originate in the cerebellopontine angle (CPA). This retrospective study aimed to investigate the factors associated with outcomes following surgical resection of vestibular schwannoma in the CPA in 30 patients at a single center in Turkey, focusing on postoperative intratumoral hemorrhage. MATERIAL AND METHODS Thirty patients (mean age 42.8 years, range 17-81) underwent vestibular schwannoma surgery via a lateral suboccipital retrosigmoid approach. Patients were categorized as 'less bleeding' (n=15) or 'more bleeding' (n=15) based on the intraoperative nature of the tumor. Demographic characteristics, tumor size, extent of resection, postoperative intratumor bleeding rates, morbidity, and mortality were evaluated. RESULTS Mean tumor size was significantly larger in highly hemorrhagic tumors (3.8 cm, range 2.1-5 cm) compared with less hemorrhagic tumors (2.1 cm, range 1.8-3 cm) (P<0.001). Total resection was achieved in 60% of patients with highly hemorrhagic tumors >3 cm and chronic diseases, compared with 80% in less hemorrhagic tumors (P=0.02). Postoperative intratumoral hemorrhage occurred in 83.3% of subtotal resections in highly hemorrhagic tumors, versus 6.7% in less hemorrhagic tumors (P<0.001). CONCLUSIONS Larger vestibular schwannoma size is associated with increased hemorrhagic nature, complicating total resection. Subtotal resection in hemorrhagic tumors significantly increases the risk of postoperative bleeding and edema. When possible, total removal should be attempted to minimize complications. In cases requiring subtotal excision, careful postoperative management of coagulation and blood pressure is crucial.

Analysis of the Peritumoral Tissue Unveils Cellular Changes Associated with a High Risk of Recurrence

BACKGROUND

The management of soft-tissue sarcoma (STS) relies on a multidisciplinary approach involving specialized oncological surgery combined with other adjuvant therapies to achieve optimal local disease control. Purpose and Results: Genomic and transcriptomic pseudocapsules of 20 prospective sarcomas were analyzed and revealed to be correlated with a higher risk of recurrence after surgery.

CONCLUSIONS

A peritumoral environment that has been remodeled and infiltrated by M2 macrophages, and is less expressive of healthy tissue, would pose a significant risk of relapse and require more aggressive treatment strategies.

β 2 -Microglobulin Participates in the Development of Vestibular Schwannoma by Regulating Nuclear Factor-κB

BACKGROUND AND OBJECTIVES

Vestibular schwannoma (VS), the most common intercranial schwannoma, originates from the sheath of the vestibular nerve. The growth rate of VS varies greatly, with the tumor enlarging gradually, which can compress the peripheral nerve tissue and reveal corresponding symptoms. This study was aimed to elucidate the growth mechanism of VS by analyzing cellular changes at protein, messenger ribonucleic acid (mRNA), and other molecular levels.

METHODS

We determined mRNA and protein levels of β 2 -microglobulin (β 2 -M) and nuclear factor κB (NF-κB) in tumors of different sizes using the real-time polymerase chain reaction and Western blotting, respectively. The relationship between these factors was verified in VS primary cells cultured in vitro, and the potential role of β 2 -M and NF-κB in VS growth was elucidated.

RESULTS

In the secretions of freshly isolated tumor tissue cultured for 72 h, the concentration of β 2 -M was positively correlated with the tumor diameter. Furthermore, tumors with larger diameter showed higher expressions of β 2 -M and NF-κB at protein and mRNA level. β 2 -M treatment resulted in elevated protein expression of NF-κB and also its phosphorylated form in vitro.

CONCLUSION

β 2 -M may participate in VS growth by regulating NF-κB and act as a key regulatory molecule in VS tumor growth.

Association of Patient Frailty With Vestibular Schwannoma Resection Outcomes and Machine Learning Development of a Vestibular Schwannoma Risk Stratification Score

BACKGROUND

Patient frailty is predictive of higher neurosurgical morbidity and mortality. However, existing frailty measures are hindered by lack of specificity to neurosurgery.

OBJECTIVE

To analyze the association between 3 risk stratification scores and outcomes for nationwide vestibular schwannoma (VS) resection admissions and develop a custom VS risk stratification score.

METHODS

We identified all VS resection admissions in the National Inpatient Sample (2002-2017). Three risk stratification scores were analyzed: modified Frailty Index-5, modified Frailty Index-11(mFI-11), and Charlson Comorbidity Index (CCI). Survey-weighted multivariate regression evaluated associations between frailty and inpatient outcomes, adjusting for patient demographics, hospital characteristics, and disease severity. Subsequently, we used k-fold cross validation and Akaike Information Criterion-based model selection to create a custom risk stratification score.

RESULTS

We analyzed 32 465 VS resection admissions. High frailty, as identified by the mFI-11 (odds ratio [OR] = 1.27, P = .021) and CCI (OR = 1.72, P < .001), predicted higher odds of perioperative complications. All 3 scores were also associated with lower routine discharge rates and elevated length of stay (LOS) and costs (all P < .05). Our custom VS-5 score (https://skullbaseresearch.shinyapps.io/vs-5_calculator/) featured 5 variables (age ≥60 years, hydrocephalus, preoperative cranial nerve palsies, diabetes mellitus, and hypertension) and was predictive of higher mortality (OR = 6.40, P = .001), decreased routine hospital discharge (OR = 0.28, P < .001), and elevated complications (OR = 1.59, P < .001), LOS (+48%, P < .001), and costs (+23%, P = .001). The VS-5 outperformed the modified Frailty Index-5, mFI-11, and CCI in predicting routine discharge (all P < .001), including in a pseudoprospective cohort (2018-2019) of 3885 admissions.

CONCLUSION

Patient frailty predicted poorer inpatient outcomes after VS surgery. Our custom VS-5 score outperformed earlier risk stratification scores.