Tag: near-total resection

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Long-term tumor control in Koos grade IV vestibular schwannomas without the need for gross-total resection

J Neurosurg 140:1591–1604, 2024

The modern management of patients with Koos grade IV vestibular schwannomas (VSs) aims at functional preservation and long-term tumor control. Gross-total resection (GTR) leads to optimal tumor control but frequently also results in permanent facial nerve (FN) palsy. Subtotal resection (STR) or near-total resection (NTR) followed by a waitand-scan protocol and second-line radiation therapy (RT) in case of progressive residuals yields excellent tumor control rates with less permanent morbidity.

METHODS The authors present the results of their prospective cohort of Koos grade IV VS patients who underwent less-than-total resection followed by a wait-and-scan protocol between January 2009 and December 2019 and discuss the latest evidence on this controversial subject. The cohort was followed up with annual clinical and volumetric outcome analyses after standardized MRI.

RESULTS Forty-eight patients were included in the analysis. The mean extent of resection was 87% (median 91%, range 45%–100%), best fitting into the definition of STR rather than NTR. In 2 cases, the proximal portion of the FN at the brainstem could not be reliably identified and monitored during the initial operation, and a second-stage resection was necessary. At 4.4 years after surgery, 81% (39/48) of the tumor residuals regressed or were stable in size. The percentage of regressive tumor residuals increased over time. Nineteen percent (9/48) of the tumor residuals displayed volumetric progression within a mean time of 35 months (median 36 months, range 14–72 months), resulting in a Kaplan-Meier estimate for progression-free survival of 79% after 4 years; higher postoperative volume showed a linear correlation with higher volumetric progression (factor 1.96, 95% CI 1.67–2.30; p < 0.001). Thirty-four of the 48 (71%) patients continue to undergo a wait-and-scan protocol. Second-line RT was performed in 14 patients (29%) within a mean time of 25 months (median 23 months, range 5–54 months), 12 (86%) of whom responded with post-RT pseudoprogression, resulting in an overall tumor control rate of 96%. At the 4.4-year follow-up from the initial resection, 92% of the patients had a good facial outcome (House-Brackmann [HB] grade I or II), 6% had a fair facial outcome (HB grade III), and 2% had a poor facial outcome (HB grades IV–VI). So far, there has been no need for salvage surgery after RT.

CONCLUSIONS STR followed by observation and second-line RT in cases of progression leads to good facial outcome and an excellent tumor control rate in the longer term.

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The behavior of residual tumors and facial nerve outcomes after incomplete excision of vestibular schwannomas

 incomplete excision of vestibular schwannomas

J Neurosurg 120:1278–1287, 2014

The authors evaluated the behavior of residual tumors and facial nerve outcomes after incomplete excision of vestibular schwannomas (VSs).

Methods. The case records of all patients who underwent surgical treatment of VSs were analyzed. All patients in whom an incomplete excision had been performed were analyzed. Incomplete excision was defined as near-total resection (NTR), subtotal resection (STR), and partial resection (PR). Tumors in the NTR and STR categories were followed up with a wait-and-rescan approach, whereas the tumors in the PR category were subjected to a second- stage surgery and were excluded from this series. All patients included in the study underwent baseline MRI at the 3rd and 12th postoperative months, and repeat imaging was subsequently performed every year for 7–10 years postoperatively or as indicated clinically. Preoperative and postoperative facial function was noted.

Results. Of the 2368 patients who underwent surgery for VS, 111 patients who had incomplete excisions of VSs were included in the study. Of these patients, 73 (65.77%) had undergone NTR and 38 (34.23%) had undergone STR. Of the VSs, 62 (55.86%) were cystic and 44 (70.97%) of these cystic VSs underwent NTR. The residual tumor was left behind on the facial nerve alone in 62 patients (55.86%), on the facial nerve and vessels in 2 patients (1.80%), on the facial nerve and brainstem in 15 patients (13.51%), and on the brainstem alone in 25 patients (22.52%). In the 105 patients with normal preoperative facial nerve function, postoperative facial nerve function was House-Brackmann (HB) Grades I and II in 51 patients (48.57%), HB Grade III in 34 patients (32.38%), and HB Grades IV–VI in 20 pa- tients (19.05%). Seven patients (6.3%) showed evidence of tumor regrowth on follow-up MRI. All 7 patients (100%) who showed evidence of tumor regrowth had undergone STR. No patient in the NTR group exhibited regrowth. The Kaplan-Meier plot demonstrated a 5-year tumor regrowth-free survival of 92%, with a mean disease-free interval of 140 months (95% CI 127–151 months). The follow-up period ranged from 12 to 156 months (mean 45.4 months).

Conclusions. The authors’ report and review of the literature show that there is undoubtedly merit for NTR and STR for preservation of the facial nerve. On the basis of this they propose an algorithm for the management of incomplete VS excisions. Patients who undergo incomplete excisions must be subjected to follow-up MRI for a period of at least 7–10 years. When compared with STR, NTR via an enlarged translabyrinthine approach has shown to have a lower rate of regrowth of residual tumor, while having almost the same result in terms of facial nerve function.

 

 

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