Intraoperative direct electrocortical stimulation for glioma surgery

see also Awake surgery for glioma.

see also Resting-state functional magnetic resonance for glioma surgery.


Stimulation-induced seizures (SISs) are rare but serious events during electrocortical stimulation (ECS) mapping. SISs are most common when mapping the frontal lobe. Greater stimulation current is not associated with the identification of more cortical functional sites during glioma surgery 1).


Glioma surgery represents a significant advance with respect to improving resection rates using new surgical techniques, including intraoperative functional mappingmonitoring, and imaging. Functional mapping under awake craniotomy can be used to detect individual eloquent tissues of speech and/or motor functions in order to prevent unexpected deficits and promote extensive resection. In addition, monitoring the patient’s neurological findings during resection is also very useful for maximizing the removal rate and minimizing deficits by alarming that the touched area is close to eloquent regions and fibers. Assessing several types of evoked potentials, including motor evoked potentials (MEPs), sensory evoked potentials (SEPs), and visual evoked potentials (VEPs), is also helpful for performing surgical monitoring in patients under general anesthesia (GA) 2).


The greater extent of resection (EOR) of low-grade gliomas is associated with improved survival. Proximity to eloquent cortical regions often limits resectability and elevates the risk of surgery-related deficits. Therefore, functional localization of eloquent cortex or subcortical fiber tracts can enhance the EOR and functional outcomeImaging techniques such as functional MRI and diffusion tensor imaging fiber tracking, and neurophysiological methods like navigated transcranial magnetic stimulation and magnetoencephalography, make it possible to identify eloquent areas prior to resective surgery and to tailor indication and surgical approach but also to assess the surgical risk. Intraoperative monitoring with direct cortical stimulation and subcortical stimulation enables surgeons to preserve essential functional tissue during surgery. Through tailored, pre-and intraoperative mapping and monitoring the EOR can be maximized, with reduced rates of surgery-related deficits 3).


As the most accurate and reliable method of brain functional area positioning, Intraoperative direct electrocortical stimulation is able to determine in real-time the parts of the brain necessary for such functions as movementsensationlanguage, and even memory. A meta-analysis suggested that it could also improve the degree of resection of glioma while reducing the incidence of permanent neurological dysfunction 4).


Findings suggest that surgeons using Intraoperative direct electrocortical stimulation and awake craniotomy during their resections of high-grade glioma in eloquent areas experienced better surgical outcomes: a significantly longer overall postoperative survival, a lower rate of postoperative complications, and a higher percentage of GTR 5).


Resting-state functional magnetic resonance imaging likely reflects similar neural information as detected with intraoperative direct electrocortical stimulation (DES), but in its current form does not reach the spatial resolution of DES. 6).


1)

Muster RH, Young JS, Woo PYM, Morshed RA, Warrier G, Kakaizada S, Molinaro AM, Berger MS, Hervey-Jumper SL. The Relationship Between Stimulation Current and Functional Site Localization During Brain Mapping. Neurosurgery. 2021 May 13;88(6):1043-1050. doi: 10.1093/neuros/nyaa364. PMID: 33289525; PMCID: PMC8117445.
2)

Saito T, Muragaki Y, Maruyama T, Tamura M, Nitta M, Okada Y. Intraoperative Functional Mapping and Monitoring during Glioma Surgery. Neurol Med Chir (Tokyo). 2015;55 Suppl 1:1-13. PMID: 26236798.
3)

Ottenhausen M, Krieg SM, Meyer B, Ringel F. Functional preoperative and intraoperative mapping and monitoring: increasing safety and efficacy in glioma surgery. Neurosurg Focus. 2015 Jan;38(1):E3. doi: 10.3171/2014.10.FOCUS14611. PMID: 25552283.
4)

De Witt Hamer PC, Robles SG, Zwinderman AH, Duffau H, Berger MS. Impact of intraoperative stimulation brain mapping on glioma surgery outcome: a meta-analysis. J Clin Oncol. 2012;30:2559–2565. doi: 10.1200/JCO.2011.38.4818.
5)

Gerritsen JKW, Arends L, Klimek M, Dirven CMF, Vincent AJE. Impact of intraoperative stimulation mapping on high-grade glioma surgery outcome: a meta-analysis. Acta Neurochir (Wien). 2019 Jan;161(1):99-107. doi: 10.1007/s00701-018-3732-4. Epub 2018 Nov 21. PMID: 30465276; PMCID: PMC6331492.
6)

van Lieshout J, Debaene W, Rapp M, Noordmans HJ, Rutten GJ. fMRI Resting-State Connectivity between Language and Nonlanguage Areas as Defined by Intraoperative Electrocortical Stimulation in Low-Grade Glioma Patients. J Neurol Surg A Cent Eur Neurosurg. 2021 Feb 22. doi: 10.1055/s-0040-1721757. Epub ahead of print. PMID: 33618418.

Intracranial metastases surgery

Intracranial metastases surgery

see Intracranial metastases surgery indications.

Intracranial Metastases Surgical Technique.


Automated classification of brain metastases and healthy brain tissue is feasible using optical coherence tomography imaging, extracted texture features, and machine learning with principal component analysis (PCA) and support-vector machines (SVM). The established approach can prospectively provide the surgeon with additional information about the tissue, thus optimizing the extent of tumor resection and minimizing the risk of local recurrences 1).

Wolpert et al. defined risk profiles for the development of BM-related epilepsy and derived a score which might help to estimate the risk of post-operative seizures and identify individuals at risk who might benefit from primary prophylactic antiepileptic drug therapy 2).


1)

Möller J, Bartsch A, Lenz M, Tischoff I, Krug R, Welp H, Hofmann MR, Schmieder K, Miller D. Applying machine learning to optical coherence tomography images for automated tissue classification in brain metastases. Int J Comput Assist Radiol Surg. 2021 May 30. doi: 10.1007/s11548-021-02412-2. Epub ahead of print. PMID: 34053010.
2)

Wolpert F, Lareida A, Terziev R, Grossenbacher B, Neidert MC, Roth P, Poryazova R, Imbach L, Le Rhun E, Weller M. Risk factors for the development of epilepsy in patients with brain metastasis. Neuro Oncol. 2019 Sep 10. pii: noz172. doi: 10.1093/neuonc/noz172. [Epub ahead of print] PubMed PMID: 31498867.

Thoracolumbar spondylodiscitis surgery

Thoracolumbar spondylodiscitis surgery

see Spondylodiscitis surgery indications.

The aim of a study was to investigate the suitability of percutaneous posterior pedicle screw fixation for surgical treatment in patients with thoracolumbar spondylodiscitis.

Janssen et al. conducted a retrospective review of a consecutive cohort of patients undergoing surgical treatment for thoracolumbar spondylodiscitis between January 2017 and December 2019. They assessed intraoperative and clinical data, comparing the classic open and the percutaneous approach. In total, they analyzed 125 cases (39 female, 86 male). The mean age was 69.49 years ± 12.63 years.

Forty-seven (37.6%) patients were operated on by a percutaneous approach for pedicle screw fixation, and 78 (62.4%) received open surgery. There was no significant difference in the mean age of patients between both groups (p= 0.57). The time of surgery for percutaneous fixation was statistically significantly shorter (p= 0.03). Furthermore, the estimated intraoperative blood loss was significantly lower in the minimally invasive group (p < 0.001). No significant difference could be observed regarding the recurrence rate of spondylodiscitis and the occurrence of surgical site infections (p= 0.2 and 0.5, respectively).

Percutaneous posterior pedicle screw fixation appears to be a feasible option for the surgical treatment of a selected patient group with spondylodiscitis of the thoracic spine and lumbar spine 1).

Although minimally invasive spine stabilization (MISt) with percutaneous pedicle screws is less invasive, percutaneous sacropelvic fixation techniques are not common practice.

Surgical intervention is indicated if neurological deficit, progressive deformity, failure to respond to conservative treatment, or the need to obtain specimens to identify causative pathogens is present. However, traditional anterior debridement and reconstruction with or without posterior instrumentation are associated with high rates of morbidity and mortality, especially in elderly immunocompromised patients and patients with multiple comorbidities. Percutaneous endoscopic discectomy, debridement, and drainage provide a minimally invasive surgical choice for the treatment of infectious spondylodiscitis 2) 3) 4).

High rates of fusion and infection clearance have been reported with anterior lumbar interbody fusion (ALIF), but this approach requires a morbid exposure, associated with non-trivial rates of vascular and peritoneal complications. XLIF is an increasingly popular interbody fusion technique that utilizes a fast and minimally invasive approach, sparing the anterior longitudinal ligament, and allowing sufficient visualization of the intervertebral discs and bodies to debride and place a large, lordotic cage. The outcome measures for this study included lumbar lordosis, sagittal balance, subsidence, fusion, pain, neurological deficit, and microbiology/laboratory evidence of infection. The mean follow-up time was 9.3months. All patients had improvements in pain and neurological symptoms. The mean lordosis change was 11.0°, from 23.1° preoperatively to 34.0° postoperatively. Fusion was confirmed with CT scans in five of six patients. At the last follow-up, all patients had normalization of inflammatory markers, no symptoms of infection, and none required repeat surgical treatment for spondylodiscitis. XLIF with percutaneous posterior instrumentation is a minimally invasive technique with reduced morbidity for lumbar spine fusion which affords adequate exposure to the vertebral bodies and discs to aggressively debride necrotic and infected tissue.

XLIF may be a safe and effective alternative to ALIF for the treatment of spondylodiscitis 5).


High rates of fusion and infection clearance have been reported with anterior lumbar interbody fusion (ALIF), but this approach requires a morbid exposure, associated with non-trivial rates of vascular and peritoneal complications. XLIF is an increasingly popular interbody fusion technique which utilizes a fast and minimally invasive approach, sparing the anterior longitudinal ligament, and allowing sufficient visualization of the intervertebral discs and bodies to debride and place a large, lordotic cage. The outcome measures for this study included lumbar lordosis, sagittal balance, subsidence, fusion, pain, neurological deficit, and microbiology/laboratory evidence of infection. The mean follow-up time was 9.3months. All patients had improvements in pain and neurological symptoms. The mean lordosis change was 11.0°, from 23.1° preoperatively to 34.0° postoperatively. Fusion was confirmed with CT scans in five of six patients. At the last follow-up, all patients had normalization of inflammatory markers, no symptoms of infection, and none required repeat surgical treatment for spondylodiscitis. XLIF with percutaneous posterior instrumentation is a minimally invasive technique with reduced morbidity for lumbar spine fusion which affords adequate exposure to the vertebral bodies and discs to aggressively debride necrotic and infected tissue.

XLIF may be a safe and effective alternative to ALIF for the treatment of spondylodiscitis 6).


Mini-open anterior debridement and lumbar interbody fusion in combination with posterior percutaneous fixation via a modified ALIF approach results in little surgical trauma and intraoperative blood loss, acceptable postoperative complications, and is effective and safe for the treatment of single-level lumbar pyogenic spondylodiscitis. This approach could be an alternative to the conventional open surgery 7).


Funao et al., describe two cases in which spondylodiscitis in the lumbosacral spine was treated with a percutaneous stabilization using S2 alar-iliac (S2AI) screw technique.

Case 1: a 77-year-old male presented with low back pain and high fever. He was diagnosed with spondylodiscitis at L4-5. He had a history of lung cancer, which was complicated by the recurrence. Because non-surgical treatment failed, MISt with percutaneous S2AI screws was performed. The patient’s low back pain subsided markedly one week after surgery, and there was no screw/rod breakage or recurrence of infection during follow-up period.

Case 2: a 71-year-old male presented with hemiparesis due to a stroke. He also developed high fever and was diagnosed with spondylodiscitis at L5-S. Because non-surgical treatment failed, the patient was treated by MISt with percutaneous S2AI screws while being maintained on anticoagulants for stroke. Although his clinical symptoms had markedly improved, a postoperative lumbar computed tomography demonstrated a bone defect at L5-S. An anterior spinal fusion with an iliac bone graft at L5-S was performed when a temporary cessation of anticoagulants was permitted. Both patients tolerated the procedures well, and had no major perioperative complications.

MISt with percutaneous S2AI screws was less invasive and efficacious for lumbosacral spondylodiscitis in providing rigid percutaneous sacropelvic fixation 8).


1)

Janssen IK, Jörger AK, Barz M, Sarkar C, Wostrack M, Meyer B. Minimally invasive posterior pedicle screw fixation versus open instrumentation in patients with thoracolumbar spondylodiscitis. Acta Neurochir (Wien). 2021 Mar 3. doi: 10.1007/s00701-021-04744-z. Epub ahead of print. PMID: 33655377.
2)

Fu T.-S., Chen L.-H., Chen W.-J. Minimally invasive percutaneous endoscopic discectomy and drainage for infectious spondylodiscitis. Biomedical Journal. 2013;36(4):168–174. doi: 10.4103/2319-4170.112742.
3)

Ito M., Abumi K., Kotani Y., Kadoya K., Minami A. Clinical outcome of posterolateral endoscopic surgery for pyogenic spondylodiscitis: results of 15 patients with serious comorbid conditions. Spine. 2007;32(2):200–206. doi: 10.1097/01.brs.0000251645.58076.96.
4)

Yang S.-C., Fu T.-S., Chen H.-S., Kao Y.-H., Yu S.-W., Tu Y.-K. Minimally invasive endoscopic treatment for lumbar infectious spondylitis: a retrospective study in a tertiary referral center. BMC Musculoskeletal Disorders. 2014;15(1, article 105) doi: 10.1186/1471-2474-15-105.
5) , 6)

Blizzard DJ, Hills CP, Isaacs RE, Brown CR. Extreme lateral interbody fusion with posterior instrumentation for spondylodiscitis. J Clin Neurosci. 2015 Jun 29. pii: S0967-5868(15)00282-9. doi: 10.1016/j.jocn.2015.05.021. [Epub ahead of print] PubMed PMID: 26138052.
7)

Lin Y, Li F, Chen W, Zeng H, Chen A, Xiong W. Single-level lumbar pyogenic spondylodiscitis treated with mini-open anterior debridement and fusion in combination with posterior percutaneous fixation via a modified anterior lumbar interbody fusion approach. J Neurosurg Spine. 2015 Sep 4:1-7. [Epub ahead of print] PubMed PMID: 26340382.
8)

Funao H, Kebaish KM, Isogai N, Koyanagi T, Matsumoto M, Ishii K. Utilization of a technique of percutaneous S2-alar-iliac fixation in immunocompromised patients with spondylodiscitis: Two case reports. World Neurosurg. 2016 Oct 15. pii: S1878-8750(16)31006-3. doi: 10.1016/j.wneu.2016.10.018. PubMed PMID: 27756675.
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