Sam Ng

Dr. Sam Ng

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Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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20 December 2019 in Journal of NeuroInterventional Surgery
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Journal Article
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SNSam Ng
Sam Ng
IDImad Derraz
Imad Derraz
JBJulien Boetto
Julien Boetto
CDCyril Dargazanli
Cyril Dargazanli
GPGaëtan Poulen
Gaëtan Poulen
VCVincent Costalat
Vincent Costalat
Background Chronic subdural hematoma (CSDH) is a common condition requiring surgical treatment; however, recurrence occurs in 15% of cases at 1 year. Middle meningeal artery (MMA) embolization has recently emerged as a promising treatment to prevent CSDH recurrence. Objective To investigate the effect of MMA embolization on hematoma volume resorption (HVR) after surgery in symptomatic patients. Methods From April 2018 to October 2018, participants with CSDH requiring surgery were prospectively randomized in a pilot study, and received either surgical treatment alone (ST group) or surgery and adjuvant MMA embolization (ST+MMAE group). The primary outcome was HVR measured on the 3 month CT scan compared with the immediate pre-embolization CT scan. Secondary outcomes were clinical recurrence of CSDH and safety measures. Results 46 patients were randomized and 41 of these achieved a 3 month follow-up . Twenty-one patients received MMA embolization. At 3 months, the HVR from postsurgical level was higher in the ST+MMAE group (mean difference 17.5 mL, 95% CI 3.87 to 31.16 mL; p=0.015). Two participants presented a CSDH recurrence (one in each group). One patient died (ST group). No MMA embolization-related adverse events were reported. Conclusion The addition of MMA embolization to surgery led to an increase in CSDH resorption at 3 months. One recurrence of CSDH was reported in each group, and there were no treatment-related complications.

13 January 2020 in Journal of Neuro-Oncology
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SNSam Ng
Sam Ng
FFFranklin Fomekong
Franklin Fomekong
VDViolaine Delabar
Violaine Delabar
TJTimothée Jacquesson
Timothée Jacquesson
CECiprian Enachescu
Ciprian Enachescu
EJEmmanuel Jouanneau
Emmanuel Jouanneau

20 September 2024 in The Lancet Regional Health - Europe
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Journal Article
Open access
SNSam Ng
Sam Ng
VRValérie Rigau
Valérie Rigau
SMSylvie Moritz-Gasser
Sylvie Moritz-Gasser
CGCatherine Gozé
Catherine Gozé
ADAmélie Darlix
Amélie Darlix
HDHugues Duffau
Hugues Duffau
In isocitrate dehydrogenase (IDH)-mutant low-grade gliomas (LGGs), awake functional-based resection (i.e., resection based on intraoperative functional responses rather than anatomical margins) has emerged as an efficient method to reduce tumour volume (TV) while minimizing postoperative deficits. Here, our goal was to assess the long-term onco-functional outcomes after awake functional-based resection in IDH-mutant LGGs, in conjunction with clinico-radiological and molecular factors. We retrospectively studied a consecutive cohort (June 1997–January 2023) of 949 patients. Six hundred patients with IDH-mutant LGGs benefited from an awake functional-based resection with a median follow-up of 7.8 years (95% Confidence interval [CI]: 7.1–8.4 years). The main outcomes were the overall survival (OS), the OS with Karnofsky performance status ≥80% (OSKPS≥80%), cognition measures, and professional activities at 12 months post-surgery. 600 patients were included in the cohort (274 female [46.0%], median age: 36 years [Interquartile range, IQR: 30–44 years]). The rate of return to work was 93.7%. The impact of surgery on cognition was of limited magnitude. The median postsurgical TV of 2.5 mL (IQR: 0–8.0 mL). The median OS was over 20 years (median: NA, 95% CI: 17.0-NA years). The median OSKPS≥80% was 14.7 years (95% CI: 13.2–17.2 years). Factors associated with longer OS and OSKPS≥P80% were 1p19q codeletion (Hazard ratio [HR]OS: 0.27, 95% CI: 0.16–0.43, HRKPS≥80%:0.25, 95% CI: 0.17–0.36), supratotal resection (HROS: 0.08, 95% CI: 0.005–0.40, HRKPS≥80%:0.12, 95% CI: 0.03–0.34) and total resection (HROS: 0.31, 95% CI: 0.16–0.59, HRKPS≥80%:0.21, 95% CI: 0.12–0.36). Recursive partitioning analyses established three OS and OSKPS≥80% prognostic groups, highlighting the contributions of histomolecular status, extent of resection, postsurgical and presurgical TV. Further propensity-matching analyses confirmed the oncological benefits of supratotal resections. Awake functional-based resection surgery in newly diagnosed IDH-mutant grade 2 LGG, was an effective strategy associated with long survival (median OS over 20 years) and long-term preservation of autonomy. More complete tumor resections favored better onco-functional outcomes across all molecularly-defined subtypes. Short-term effects were of limited magnitude regarding postoperative cognitive and professional outcomes. Supratotal functional-based resections offered additional survival benefits. None.

1 September 2021 in Journal of Neurosurgery
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Journal Article
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SNSam Ng
Sam Ng
GHGuillaume Herbet
Guillaume Herbet
ALAnne-Laure Lemaitre
Anne-Laure Lemaitre
JCJérôme Cochereau
Jérôme Cochereau
SMSylvie Moritz-Gasser
Sylvie Moritz-Gasser
HDHugues Duffau
Hugues Duffau
OBJECTIVE: Early surgery in presumed asymptomatic patients with incidental low-grade glioma (ILGG) has been suggested to improve maximal resection rates and overall survival. However, no study has reported on the impact of such preventive treatment on cognitive functioning. The aim of this study was to investigate neuropsychological outcomes in patients with ILGG who underwent preventive surgery. METHODS: This was a retrospective analysis of a consecutive series of patients with ILGG who underwent awake surgery and who had presurgical and 3-month postsurgical neuropsychological assessments. Data were normalized into z-scores and regrouped by cognitive domains. Clinicoradiological data, histomolecular profile, and differences in z-scores (Δz-scores) were analyzed. RESULTS: Forty-seven patients were included (mean age 39.2 ± 11.3 years). Twenty-eight patients (59.6%) underwent supratotal or total resections. All patients were still alive after a mean follow-up of 33.0 ± 30.8 months. Forty-one patients (87.2%) had stable (n = 34, 72.3%) or improved (Δz-score > 1; n = 7, 14.9%) neurocognitive outcomes after surgery. Six patients (12.8%) presented a slight impairment (Δz-score < −1) in at least one cognitive domain. The mean presurgical and postsurgical z-scores were comparable except in the psychomotor speed and attention domain. A significant correlation between presurgical executive functioning and tumor volume was reported, whereas the extent of resection and histomolecular profile did not impact neuropsychological outcomes. CONCLUSIONS: Early surgical treatment in presumed asymptomatic patients with ILGG was associated with stable or improved neuropsychological outcomes in 87.2% of patients at 3 months, with only mild cognitive decline observed in 6 patients. In return, supratotal or total resections were achieved in most patients, and all patients were still alive at the end of the follow-up.

20 July 2023 in Cancers
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SNSam Ng
Sam Ng
HDHugues Duffau
Hugues Duffau
The ability of neural circuits to compensate for damage to the central nervous system is called postlesional plasticity. In diffuse low-grade gliomas (LGGs), a crosstalk between the brain and the tumor activates modulations of plasticity, as well as tumor proliferation and migration, by means of paracrine and electrical intercommunications. Such adaptative mechanisms have a major impact on the benefits and risks of oncological treatments but are still disregarded by current neuro-oncological guidelines. In this review, the authors first aimed to highlight clinical, radiological, and oncological markers that robustly reflect the plasticity potentials and limitations in LGG patients, including the location of the tumor and the degree of critical white matter tract infiltration, the velocity of tumor expansion, and the reactional changes of neuropsychological performances over time. Second, the interactions between the potential/limitations of cerebral plasticity and the efficacy/tolerance of treatment options (i.e., surgery, chemotherapy, and radiotherapy) are reviewed. Finally, a longitudinal and multimodal treatment approach accounting for the evolutive profiles of brain plasticity is proposed. Such an approach integrates personalized predictive models of plasticity potentials with a step-by-step therapeutic decision making and supports onco-functional balanced strategies in patients with LGG, with the ultimate aim of optimizing overall survival and quality of life.

30 April 2021 in Scientific Reports
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Journal Article
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SNSam Ng
Sam Ng
GHGuillaume Herbet
Guillaume Herbet
ALAnne-Laure Lemaitre
Anne-Laure Lemaitre
SMSylvie Moritz-Gasser
Sylvie Moritz-Gasser
HDHugues Duffau
Hugues Duffau
Brain awake surgery with cognitive monitoring for tumor removal has become a standard of treatment for functional purpose. Yet, little attention has been given to patients’ interpretation and awareness of their own responses to selected cognitive tasks during direct electrostimulation (DES). We aim to report disruptions of self-evaluative processing evoked by DES during awake surgery. We further investigate cortico-subcortical structures involved in self-assessment process and report the use of an intraoperative self-assessment tool, the self-confidence index (SCI). Seventy-two patients who had undergone awake brain tumor resections were selected. Inclusion criteria were the occurrence of a DES-induced disruption of an ongoing task followed by patient’s failure to remember or criticize these impairments, or a dissociation between patient’s responses to an ongoing task and patient’s SCI. Disruptions of self-evaluation were frequently associated with semantic disorders and critical sites were mostly found along the left/right ventral semantic streams. Disconnectome analyses generated from a tractography-based atlas confirmed the high probability of the inferior fronto-occipital fasciculus to be transitory ‘disconnected’. These findings suggest that white matters pathways belonging to the ventral semantic stream may be critically involved in human self-evaluative processing. Finally, the authors discuss the implementation of the SCI task during multimodal intraoperative monitoring.