75. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie

Vorsitz

Prof. Dr.

Prof. Dr. med.

Dr. med.

Immunohistochemical expression of COX2 in vestibular schwannomas is associated with the infiltration by M2 macrophages, increased proliferation and bigger tumor size

Tumor

Die immunhistochemische Expression von COX2 in Vestibularisschwannomen ist mit der Infiltration durch M2-Makrophagen, einer stärkeren Proliferation und ausgedehnterer Tumorgröße verbunden.

There is increasing evidence for the involvement of inflammatory processes in the genesis and growth of vestibular schwannomas. COX2 has been shown to be highly expressed in vestibular schwannomas and its role in tumor progression and as a potential therapy target are frequently discussed. However, the role of COX2 in vestibular schwannoma is still poorly understood.We analyzed the expression of COX2 and markers for macrophage (CD163 and CD68) and lymphocyte infiltration (CD3 and CD8) in 1065 vestibular schwannoma tumor samples. Semiquantitative scoring systems were applied for the assessment of COX2, CD163 and CD68 expression while CD3 and CD8 immunopositivity was quantified via manual counting. Furthermore, clinical data was included in the uni- and multivariate analyses. .An increased COX2 expression was associated with more extensive macrophage infiltration in vestibular schwannoma samples (CD68 and CD163 each p<0.0001). Additionally, lymphocyte detection was also higher in tumors with higher COX2 immunopositivity (CD3 and CD8 each p<0.0001). Furthermore, with each higher score for COX2 expression the infiltration with lymphocytes and macrophages increased significantly (p<0.0001). The extent of COX2 expression in vestibular schwannomas is clearly correlated with increased infiltration with lymphocytes and macrophages reflecting inflammatory processes.

Abstractvortrag | Abstract talk

Dott.

Prediction of radioresistance and early identification of tumor relapse after Gamma-Knife radiosurgery in vestibular schwannomas: A retrospective cohort study

Prädiktive Faktoren für die Strahlenresistenz und frühzeitige Erkennung eines Tumorrezidivs nach Gamma-Knife Radiochirurgie bei Vestibularisschwannome: eine retrospektive Kohortenstudie

As microsurgical resection after failed radiosurgery is associated with higher morbidity in patients with vestibular schwannoma (VS), the identification of factors that may influence radioresistance plays a critical role. Additionally, differentiating between treatment-related changes (pseudoprogression) and tumor relapse (TR) can often be challenging. This study aims to identify radioresistance predicting factors and, secondly, to differentiate pseudoprogression from TR at an early stage.A cohort of 705 patients with unilateral sporadic vestibular schwannoma who underwent stereotactic radiosurgery (SRS) at the same center from 1998 to 2020 was retrospectively analyzed. Clinical data concerning symptoms, tumor volume (Hannover and OHATA Classification), side effects of SRS were recorded. Of these patients, 598 achieved remission while 107 experienced TR and required a second treatment, either microsurgical resection or SRS.In our cohort, TR was significantly higher in women (p<0.05). However, clinical symptoms such as facial palsy, hypoacusis, tinnitus, and vertigo, as well as tumor volume and tumor configuration (cystic vs solid), were not predictive factors for radioresistance. Patients who experienced TR had significantly more side effects of SRS (20.6% vs 8.4%, p<0.001), particularly regarding facial spasm (p<0.001). A higher risk of facial spasm was significantly related to OHATA-Class (A>B>C>D). An earlier recurrence was observed in cystic tumors. The average follow-up period was 4 years for the recurrence group and 7 years and 10 months for the remission group. Regarding the trend of relative and absolute tumor volumes, a significant difference (p<0.001) was observed between patients with and without TR. This became noticeable at 12 months and even more evident at 24 months after SRS. In this time frame, patients without TR had a decrease in volume, while patients with TR showed an increase.Clinical symptoms, tumor volume, and tumor configuration are not predictive factors of TR. Only female sex predisposes to an increased risk of TR. Patients with TR experience significantly higher side effects of SRS, particularly facial spasm. TR is strongly suspected at 12 months and even more at 24 months after SRS if there is a further increase in absolute and relative tumor volume, making pseudoprogression unlikely.

PD Dr.

Recovery of post-operative facial palsy after microsurgery (retrosigmoid approach) of vestibular schwannoma

Unterschiedliche Rate der postoperative Erholung der Facialisfunktion nach retrosigmoidaler Resektion von Vestibularisschwannomen

Postoperative facial palsy after microsurgical resection of vestibular schwannoma (VS) is often only temporary. This study aims to in detail analyze the long-term recovery rates and development of facial motoric function after surgical tumor resection according early post-operative motoric facial status.Patients treated between 2008 and 2015 with primary retrosigmoid resection for vestibular schwannoma via retrosigmoid approach with anatomical preservation of the facial nerve and sufficient follow-up were included. Patients with pre-operative facial nerve affection were excluded. Facial motoric function was quantified by House-Brackman (HB) scale and patients photographs were taken prospectively. Other clinical information was retrospectively analyzed. HB I-II was defined as good and HB III-VI as poor facial outcome.N=521 patients were included in this analysis. Overall, long-term good facial outcome was achieved in 85%, while 15% presented with long-term relevant facial palsy. 46% (N=241/521) of all patients presented with early post-operative HB I. 20% (N=106/521) presented with a slight post-operative deterioration of HB II, of which 94% (N=100/106) recovered spontaneously after one year to HB I. Only one patient experienced a worsening of early-postoperative HB II to long-term HB III. 11% (N=58/521) had an early post-operative HB III, of which 84% recovered spontaneously at one year follow-up to good facial outcome. 16% (N=82/521) presented with early post-operative HB IV, of which 50% had recovered to good facial outcome at 1-year-FU. HB V was present early-post operative in 6% (N=31/521), of which 32% recovered to good facial outcome. 0.6% (N=3/521) presented with HB VI, of which only one recovered to HB II. Post-operative facial palsy recovery was independent of patient sex, and patient age (p=0.432; p=0.458).Long-term post-operative recovery rate after VS surgery of a direct postoperative status of HB II to HB I is 94%. If severe facial deterioration (HB III-IV) occurred, the best recovery rate was at HB III with 84%, followed by 50% at HB IV, and only 32 % at HB V. Postoperative facial palsy recovery was independent of patient demographics (age, sex, etc).

Surgical monotherapy in vestibular schwannoma: The impact of distinct extent of resection grades on long-term tumor control parameters

Der Einfluss einer detaillierten Klassifikation des Resektionsausmaßes in der chirurgischen Behandlung von Vestibularisschwannomen auf die Paramater der Langzeit-Tumorkontrolle

Residual tumor after vestibular schwannoma (VS) resection has been associated with higher incidence of recurrence. However, the definition of residual tumor is very heterogenous. Subtotal resection (STR) is most frequently used on its own, only seldom near-total-resection (NTR) and decompressive surgery (DS) is added to the extent of resection classification. This study aims to analyze clinical tumor control parameters in NTR, STR, DS and gross total resection (GTR).This is a retrospective cohort study of solitary VS patients treated with microsurgical resection by retrosigmoid resection between 2005 and 2012. Patients were contacted 10 years after surgery report on radiographic tumor control by gadolinium-contrast-enhanced magnetic resonance imaging (MRI). Patients and tumor characteristics were collected retrospectively.N=426 patients met the inclusion criteria and were included in this analysis. Overall, the rate of GTR was 94%, with 3% NTR and 3% STR. Mean time of follow-up was 5.6 years. 100% patients of Koos I were managed by GTR. In Koos II 1% received NTR, and none received STR. In Koos III 2% received STR and 3% received NTR. The highest rate of STR was present in Koos IV with 6% STR and 2% NTR. In GTR, the long-term recurrence rate was 5%, which was significantly lower compared in NTR (16%) and STR (54%). The recurrent event per one million patient days was 16 in GTR, 62 in NTR and 130 in STR. The median time to recurrence was the longest in NTR (7.2 years) and GTR (6.2 years), compared to STR (5.6 years).The rate of STR and NTR rose with tumor size. The rate of recurrent events was significantly more frequent in STR and NTR. However, there is a difference in time to recurrence and frequency of recurrent events between NTR and STR themselves – therefore a more detailed classification in EOR of VS should be put forward to differentiate these clearly different patient groups with different postoperative oncological behavior. This would also benefit the current discussion on, which patient should be treated with adjuvant radiosurgery after sub- and or near-total resection. Follow-Up should be longer then 5 years to uncover the true rate of recurrence after surgical resection in VS.

PD. Dr.

The role of microsurgery in the first line treatment of vestibular schwannoma: It is all about the odds

Ab welchem Rezidivrisiko lohnt sich die chirurgische Intervention in der Erstlinienbehandlung von Vestibularisschwannomen?

Given the risk for a deterioration of facial function (FDR), first-line (1stline) microsurgery (MS) is discouraged in vestibular schwannoma (VS). In contrast, 1stline radiosurgery (SRS) preserves facial function but has a higher recurrence rate (RR). As salvage VS surgery is very challenging, it could be reasonable to accept a slightly increased FDR of 1stline MS in favor of the lower RR. The aim of the present study was to determine the FDR and RR values of salvage surgery and to calculate the break-even point of MS in the 1stline VS treatment.This retrospective study analyzed all patients with unilateral VS undergoing microsurgery between 03/2008 and 10/2021 (n=1470). We identified patient with 2ndline MS after previous MS (MS-MS) or radiosurgery (SRS-MS) as well as patients with 3rdline MS (MS-SRS-MS). After reviewing patients" clinical and imaging data, we determined FDR and RR for each cohort. This data was compared to a 1stline MS cohort (CTRL) with a follow-up of at least 10 years (n=572). A mathematical prediction model (MPM) was applied to calculate the odds ratio (OR) of different treatment strategies (i.e., MS-MS, SRS-MS, MS-SRS-MS) depending on different FDR and RR values.In our cohort, there were 48 patients with 2ndline and 11 patients with 3rdline MS after failed MS/SRS. Time to recurrence in relation to the initial treatment was shortest in SRS-MS (35±34 mo) compared to MS-MS (128±179 mo) and MS-SRS-MS (38±17 mo). These patients had a significant worse preoperative facial function than CTRL patients. Extent-of-resection (EOR) was diminished in 2ndline (79% and 75%) compared to 1stline MS (97%). Both the FDR and RR were significantly increased in MS-MS (FDR:17%, RR:14%) and SRS-MS (FDR:45%, RR:5%) compared to CTRL (FDR:12%, RR:4%). Notably, MS-SRS-MS was associated with the highest FDR (60%) while having the lowest GTR rate (54%). MPM indicated that FDR<15% and RR<5% justify a 1stline MS. In the present cohort, these criteria were met for Koos 1-3 tumors (FDR:0-7%, RR:0-3%).Recurrent VS surgeries fare much worse considering FDR, EOR and RR than first-line surgeries. Hence, reducing the RR of the first-line VS treatment is required. In smaller VS, the surgical oncofunctional outcome can reach the break-even point favoring microsurgery over radiosurgery as first-line treatment option. However, in situations with high FDR (e.g., large or cystic VS) a more conservative surgical approach might be beneficial.

Postoperative pneumocephalus after posterior fossa surgeries in the semi-sitting position – Comparison of intracranial air collections and clinical outcome according to the surgical approach by means of voxel-based volumetry

Postoperativer Pneumozephalus nach Operationen der hinteren Schädelgrube in halbsitzender Position - Vergleich von intrakranieller Luftmenge und klinischem Outcome abhängig vom operativen Zugangsweg mittels voxelbasierter Volumetrie

To assess the extent and distribution of postoperative pneumocephalus in patients undergoing posterior fossa surgery in the semi-sitting position after midline vs. lateral surgical approaches.In a retrospective analysis 465 patients who underwent posterior fossa surgery in the semi-sitting position were included. Patients" individual postoperative CCT scans were registered and normalized to the common MNI space. Intraventricular, subdural, and total intracranial air were measured by voxel-based volumetry and compared between patient groups according to the surgical approach. Clinical details such as age, duration of surgery and outcome were evaluated.Indication for surgery was resection of a posterior fossa tumor in 95.9% (n=446) of which 69.0% were vestibular schwannomas and 18.1% meningiomas. A lateral suboccipital (LA) and a midline suboccipital approach (MA) were performed in 92.0% (n=428) and in 8.0% (n=37), respectively. The total intracranial air volume (38ml vs. 29ml, p=0.049) and the intraventricular air volume (9.2ml vs. 0.0ml, p<0.001) were significantly higher in MAs. Clinically relevant tension pneumocephalus (TP) was present in a total of 3.0% of patients (n=14), which was treated by frontal air exchange with saline in 64.3% (n=9) and external ventricular drainage (EVD) in 35.7% (n=5). TP occurred significantly more often in MAs (10.8%) than in LAs (2.3%; p=0.019). Air replacement was performed via EVD in all cases of TP after a MA and via a frontal twist-drill in 90% of TP cases after a LA. In two patients, revision surgery was necessary after air exchange. No permanent disabilities occurred due to air replacement therapy. A weak correlation was found between total intracranial air and age (ρ=0.28, p<0.001) as well as time to extubation (ρ=0.1, p=0.026). A weak negative correlation was found between intraventricular air and BMI (ρ=-0.15, p=0.001). No association was detected between air volumes and duration of surgery, ICU or inpatient stay or postoperative Karnofsky index.MAs harbor a significantly higher risk of clinically relevant TP than LAs. These patients usually showed intraventricular air requiring external ventricular drainage as opposed to more frequent subdural air collections in LAs. Overall outcome was good even in patients requiring air replacement indicating that, if treated subsequently, the semi-sitting position can be safely performed in patients with midline pathologies.

Session 4
Tumor – Vestibularisschwannome 1

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