| Objective: The thalamus is located in the deep part of the brain,adjacent to the internal capsule,caudate nucleus and other important parts.Thalamic lesions are difficult to operate due to the difficulty of exposure and have a high mortality and disability rate[1-3].Depending on the nature of the lesion,there are different surgical approaches,including biopsy and surgical excision.There are different surgical approaches depending on the location of the lesion,and each approach has its own limitations and advantages.Most of the studies about thalamic surgical access are local anatomy of the cadaveric head,while the transcephalic tissue access,where local anatomy is more difficult to study,can be compensated by imaging anatomy at this time.The transfrontal approach involves fewer blood vessels and functional areas and is suitable for puncture biopsy,but biopsy retrieval is small and cannot be hemostatic under direct vision;therefore,biopsy or resection through neuroendoscopy deserves further study.There are various structures and nuclei surrounding the transfrontal approach pathway that affect the safety of the procedure,and exploring the anatomy of the brain tissue passing through the thalamus by the transfrontal approach is a good guide for the clinical application of this approach.In this study,a three-dimensional model of the cranial brain was established based on cranial MRI,and a quantitative microsurgical anatomical study was performed with the aim of investigating the feasibility and safety of biopsy or resection of central thalamic lesions by the transfrontal approach.The study is divided into three parts:(1)quantitative microanatomical study of MRI three-dimensional model for puncture biopsy of the central thalamic site via the frontal approach;(2)quantitative microanatomical study of MRI three-dimensional model for neuroendoscopic biopsy of the central thalamic site via the frontal approach;and(3)quantitative microanatomical study of MRI three-dimensional model for neuroendoscopic resection of the central thalamic site via the frontal approach.Methods: Thirty Parkinson’s patients with deep brain electrical stimulation and normal brain tissue structure admitted to the Department of Functional Neurosurgery of Northern Jiangsu People’s Hospital from October 2017 to June 2022 were selected.We collected patients’ preoperative MRI data,and performed 3D reconstruction of brain tissue,lateral ventricles,caudate nucleus,nucleus accumbens,internal capsule,thalamus and other structures using 3DSlicer software.The target point was determined to be the midpoint of the largest level of the thalamus,and the entry points were 11 cm,12 cm,13 cm above the nasal root and 1 cm,2 cm,2.5 cm,3 cm paracranial opening in the midline,for a total of 12 points.Channels with diameters of 2 mm,10 mm,and 20 mm were established to simulate puncture biopsy,endoscopic biopsy,and endoscopic resection,respectively.The entry point was used as a grouping basis to analyze the differences between the volumes of different parts of the surgical pathway passing through the lateral ventricle,caudate nucleus,internal capsule,nucleus accumbens,and thalamus.Results: Part I: Puncture biopsy of the central thalamus was performed in the region of 11-13 cm(anterior-posterior direction)above the nasal roots and 1-3 cm(left-right direction)pars intermedia,with a channel diameter of 2 mm.The volume of the lateral ventricles passing through the pathway was small,and the larger the pars intermedia distance,the smaller the volume passing through the lateral ventricles(P < 0.05).For the caudate nucleus,in the right-left direction,the smaller the distance of the midline paracranial opening,the smaller the volume(P < 0.05),and in the anterior-posterior direction,the more posterior the point of entry,the smaller the volume(P < 0.05).It does not pass through the nucleus pulposus.Most of them did not pass through the internal capsule,and the greater the distance of the midline paracranial opening,the greater the possibility of passing through(P > 0.05).There was no statistically significant difference between the groups passing through the thalamic volume(P > 0.05).Part II: Neuroendoscopic biopsy of the central thalamus was performed at 11-13 cm above the nasal root and 1-3 cm above the midline pars plana,with a channel diameter of 10 mm.The larger the midline pars plana distance,the smaller the volume passing through the lateral ventricles in the pathway(P < 0.05).For the caudate nucleus,the smaller the distance of the midline paracranial opening,the smaller the volume passed(P < 0.05),and the more posterior the point of entry,the smaller the volume passed(P < 0.05).Most of them did not pass through the nucleus accumbens,and the more posterior the point of entry,the less likely they were to pass through(P > 0.05).In the left-right direction,there was no statistically significant difference between the groups passing through the internal capsule volume(P > 0.05),and in the anterior-posterior direction,the more posterior the entry point,the smaller the passing volume(P < 0.05).There was no statistically significant difference in the passing thalamic volume between the groups(P > 0.05).Part III: Neuroendoscopic resection of the central thalamic lesion was performed in the area of 1-3 cm of parasternal opening 11-13 cm above the nasal root,with a channel diameter of 20 mm.In the 11 cm above the nasal root group,the greater the parasternal opening distance,the smaller the volume passing through the lateral ventricles(P < 0.05),and there was no statistically significant difference in the rest of the groups.In the left-right direction,there was no statistically significant difference in the volume of passing caudate nucleus between the groups(P > 0.05),and in the anterior-posterior direction,the more posterior the entry point was,the smaller the passing volume was(P < 0.05).In the 11-cm supra-nasal root group,the smaller the paracranial distance opening,the smaller the passing volume of the nucleus accumbens(P < 0.05),and in the anterior-posterior direction,the more posterior the point of entry,the smaller the passing volume(P < 0.05).In the 13-cm supra-nasal root group,the smaller the midline pars distant,the smaller the passing volume of the internal capsule(P < 0.05),and in the anterior-posterior direction,the more posterior the entry point face,the smaller the passing volume of the internal capsule(P < 0.05).There was no statistically significant difference in the passing thalamic volume between the groups(P > 0.05).Conclusion: Imaging anatomical studies of the transfrontal approach to reach the thalamus through MRI 3D reconstruction,simulating the biopsy or resection process can clearly show the structures through which the pathway passes and provide a reference for individualized clinical application.A safe path exists for biopsy or surgical resection of central thalamic lesions via the transfrontal approach within 11-13 cm above the nasal root and 1-3 cm of parasternal opening in the midline.In actual clinical practice,when the location of the thalamic lesion is determined,the entry point can be adjusted to avoid or minimize damage to important functional areas as much as possible,making the procedure safer. |
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