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Roman A, Anzolin E, Bianchini L. The Infratrigeminal Suprafloccular Approach to Intrapontine Lesions: An Anatomical Overview and Relevance for the Approach to Intrapontine Lesions. Cureus 2023; 15:e45708. [PMID: 37868499 PMCID: PMC10590180 DOI: 10.7759/cureus.45708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2023] [Indexed: 10/24/2023] Open
Abstract
Background and objectives Brainstem lesions have long been considered complex pathologies that may lead to permanent deficits or life-threatening complications, posing significant challenges for surgical removal. Among these lesions, intrapontine lesions are particularly challenging in the field of neurosurgery. However, with advancements in microsurgical anatomy knowledge and technology, these lesions have become more amenable to surgical treatment. In this study, the authors examine an infratrigeminal suprafloccular approach, which has been shown to be a safe surgical route, resulting in fewer postoperative complications, while evaluating the anatomical nuances of the approach and route. Methods Twenty cadaveric brainstem specimens were analyzed to assess the anatomy, focusing on the lateral aspect of the pons as a potential safe entry zone for intrapontine lesions. The authors consistently analyzed twenty brainstem specimens, carefully examining the pontine microsurgical anatomy. A triangular area of entrance was measured, with three sides or walls (X, Y, and Z) aiming to identify the safe zone that would spare the distinct pontine nuclei, ascending sensory pathways, corticospinal, corticonuclear, and corticopontine tracts of the brainstem. An illustrative case was adapted to the described safe entry zone for corroboration purposes. Results The authors measured three distinct lines on the lateral surface of the pons, named X, Y, and Z, forming a triangle in shape. Line X extended from the midpoint anteroposteriorly of the flocculus of the cerebellum to the apparent trigeminal exit in the lateral aspect of the pons. Line Y ran from the trigeminal exit in the pons to the apparent exit of the facial-vestibulocochlear complex in the far lateral aspect of the pontomedullary sulcus in the cerebellopontine fissure. Line Z represented the measurement from the vestibulocochlear complex to the midpoint anteroposteriorly of the flocculus of the cerebellum. The mean measurements were as follows: X = 14.41mm (range: 10mm to 20mm), Y = 13.1mm (range: 10mm to 21mm), and Z = 3mm (range: 2mm to 5mm). The mean surface area of the analyzed specimens within the triangle (formed by X, Y, and Z) was 20.1mm² (range: 10mm² to 40mm²). This area was identified as a safe zone for the entry of microsurgical approaches to intrapontine lesions, involving less retraction of the anterior pons and potentially sparing critical structures, such as the corticospinal tracts, pontine perforating arteries, tegmentum pontis, cranial nerve nuclei, substantia reticulata dorsally, and transverse pontine fibers. Microsurgical anatomical findings, combined with intraoperative monitoring in an illustrative case, consistently demonstrated that this entry area predicted less functional instability of the analyzed tracts and resulted in fewer postoperative complications. Conclusion Deep-seated pontine lesions present a complex range of pathologies with a high potential for devastating outcomes, particularly those involving hemorrhage. This study identifies and describes a presumed safe entry zone that allows for the creation of a surgical corridor for biopsy or microsurgical resection of these lesions, reducing morbidity in a previously considered impenetrable region.
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Affiliation(s)
- Alex Roman
- Neurological Surgery, Instituto de Neurocirurgia e Cirurgia de Coluna, Passo Fundo, BRA
| | - Eduardo Anzolin
- Neurosurgery Department, Hospital Cristo Redentor, Porto Alegre, BRA
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Le S, Nguyen V, Lee L, Cho SC, Malvestio C, Jones E, Dodd R, Steinberg G, López J. Direct brainstem somatosensory evoked potentials for cavernous malformations. J Neurosurg 2022; 137:156-162. [PMID: 34740189 PMCID: PMC10193471 DOI: 10.3171/2021.7.jns21317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 07/08/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Brainstem cavernous malformations (CMs) often require resection due to their aggressive natural history causing hemorrhage and progressive neurological deficits. The authors report a novel intraoperative neuromonitoring technique of direct brainstem somatosensory evoked potentials (SSEPs) for functional mapping intended to help guide surgery and subsequently prevent and minimize postoperative sensory deficits. METHODS Between 2013 and 2019 at the Stanford University Hospital, intraoperative direct brainstem stimulation of primary somatosensory pathways was attempted in 11 patients with CMs. Stimulation identified nucleus fasciculus, nucleus cuneatus, medial lemniscus, or safe corridors for incisions. SSEPs were recorded from standard scalp subdermal electrodes. Stimulation intensities required to evoke potentials ranged from 0.3 to 3.0 mA or V. RESULTS There were a total of 1 midbrain, 6 pontine, and 4 medullary CMs-all with surrounding hemorrhage. In 7/11 cases, brainstem SSEPs were recorded and reproducible. In cases 1 and 11, peripheral median nerve and posterior tibial nerve stimulations did not produce reliable SSEPs but direct brainstem stimulation did. In 4/11 cases, stimulation around the areas of hemosiderin did not evoke reliable SSEPs. The direct brainstem SSEP technique allowed the surgeon to find safe corridors to incise the brainstem and resect the lesions. CONCLUSIONS Direct stimulation of brainstem sensory structures with successful recording of scalp SSEPs is feasible at low stimulation intensities. This innovative technique can help the neurosurgeon clarify distorted anatomy, identify safer incision sites from which to evacuate clots and CMs, and may help reduce postoperative neurological deficits. The technique needs further refinement, but could potentially be useful to map other brainstem lesions.
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Affiliation(s)
- Scheherazade Le
- Department of Neurology, Division of Neurophysiology & Intraoperative Neuromonitoring (IONM), Stanford University School of Medicine; and
| | - Viet Nguyen
- Department of Neurology, Division of Neurophysiology & Intraoperative Neuromonitoring (IONM), Stanford University School of Medicine; and
| | - Leslie Lee
- Department of Neurology, Division of Neurophysiology & Intraoperative Neuromonitoring (IONM), Stanford University School of Medicine; and
| | - S. Charles Cho
- Department of Neurology, Division of Neurophysiology & Intraoperative Neuromonitoring (IONM), Stanford University School of Medicine; and
| | - Carmen Malvestio
- Department of Neurology, Division of Neurophysiology & Intraoperative Neuromonitoring (IONM), Stanford University School of Medicine; and
| | - Eric Jones
- Department of Neurology, Division of Neurophysiology & Intraoperative Neuromonitoring (IONM), Stanford University School of Medicine; and
| | - Robert Dodd
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California
| | - Gary Steinberg
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California
| | - Jaime López
- Department of Neurology, Division of Neurophysiology & Intraoperative Neuromonitoring (IONM), Stanford University School of Medicine; and
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Li Z, Wang M, Zhang L, Fan X, Tao X, Qi L, Ling M, Xiao X, Wu Y, Guo D, Qiao H. Neuronavigation-Guided Corticospinal Tract Mapping in Brainstem Tumor Surgery: Better Preservation of Motor Function. World Neurosurg 2018; 116:e291-e297. [PMID: 29733992 DOI: 10.1016/j.wneu.2018.04.189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 10/17/2022]
Abstract
OBJECTIVE To evaluate a new technique in brainstem surgery, neuronavigation (NN)-guided corticospinal tract (CST) mapping, in a retrospective study of patients undergoing brainstem tumor surgery. METHODS We studied 40 patients with a brainstem tumor who were enrolled in this study. Patients whose worst preoperative muscle strength of the 4 limbs was greater than 3 levels from normal on the Lovett scale were divided into 2 groups: a treatment group of 21 patients who underwent NN-guided CST mapping and routine intraoperative neurophysiology monitoring (IONM) and a control group of 19 patients who underwent routine NN and IONM. Preoperative muscle strength and postoperative (day 90 postsurgery) muscle strength were assessed and compared between the 2 groups. RESULTS In the NN-guided CST mapping group, 3 patients (14.3%) had a decrease in muscle strength by 1 level postoperatively, and no patient experienced a decrease of >1 level. In the control group, 4 patients (21.1%) had a 1-level decrease in muscle strength, and 5 (26.3%) had a decrease of >1 level. Patients in the NN-guided CST mapping group had significantly better surgical outcomes compared with those in the control group (P = 0.018, Fisher exact test). CONCLUSIONS Brainstem tumor resection using NN-guided CST mapping achieved better preservation of motor function compared with routine NN and IONM. NN-guided CST mapping not only decreased the difficulty of the surgery, but also significantly improved the efficiency of surgery.
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Affiliation(s)
- Zhibao Li
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Department of Neuroelectrophysiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Mingran Wang
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Department of Neuroelectrophysiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Liwei Zhang
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xing Fan
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Department of Neuroelectrophysiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xiaorong Tao
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Department of Neuroelectrophysiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Lei Qi
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Department of Neuroelectrophysiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Miao Ling
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Department of Neuroelectrophysiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xiong Xiao
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yuliang Wu
- Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Dongze Guo
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Department of Neuroelectrophysiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Hui Qiao
- Beijing Neurosurgical Institute, Capital Medical University, Beijing, China; Department of Neuroelectrophysiology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
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Della Puppa A, Rustemi O, Gioffrè G, Scienza R. Approaching a brainstem high-grade glioma (HGG) with the assistance of 5-aminolevulinic acid (5-ALA) technology: a new strategy for an old surgical challenge. Neurol Sci 2014; 36:797-9. [PMID: 25056195 DOI: 10.1007/s10072-014-1901-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Accepted: 07/18/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Alessandro Della Puppa
- Department of Neurosurgery, Padua University Hospital, Azienda Ospedaliera di Padova, via Giustiniani, 2, 35128, Padua, Italy,
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