Treating subcortical brain lesions in or near eloquent areas is challenging not only because lesions must be resected while preserving brain tissue involved in essential functions, but also because lesions often cannot be easily identified from the surface of the brain. Here, we report 2 cases of cerebral cavernous malformations near Broca’s area. In both cases, lesions were surgically removed by utilizing three-dimensional fusion images created using preoperative magnetic resonance imaging and computed tomography data. Excisions were completed without any worsening of speech function, and the use of presurgical simulations was found to be useful in the design and execution of the actual operations. The technique described in this report serves as a useful tool in simulating surgical strategies by using brain gyri and sulci as surgical landmarks. Furthermore, in contrast to other intraoperative techniques, this method can aid in shortening the duration of surgery and can help limit damage to eloquent areas of the brain.
Cerebral cavernous malformations are relatively benign lesions that frequently remain clinically undetectable [
Cerebral cavernous malformations exist in the subcortical regions surrounded by the brain parenchyma, and it is sometimes difficult to determine their location from the surface of the brain during surgery. Although brain navigation is a powerful tool in identifying the location of the lesions, it is a time consuming method and can be affected by brain shifts during surgery [
Functional mapping is also very important at the time of surgical intervention, especially when the cerebral cavernous malformation is located near an eloquent area or deep inside the brain. For cerebral cavernous malformations near Broca’s area, functional magnetic resonance imaging (fMRI), navigated transcranial magnetic stimulation (nTMS), or awake surgeries are the methods of choice. However, anatomical identification of the region (the inferior frontal gyrus) is also important. In this context, three-dimensional (3D) images can enable surgical teams to better understand the anatomy of the surgical field.
In this report, we introduce our surgical strategy to remove cerebral cavernous malformations near Broca’s area. We first created 3D fusion images using data from magnetic resonance (MR) and computed tomography (CT) images. Using these fusion images we simulated surgical procedures on a commercially available workstation. We think that this method, in combination with preoperative functional mapping, can be used for minimally invasive removal of cerebral cavernous malformations near Broca’s area. Our method does not require a navigation system and can also be used for surgeries of other brain lesions buried inside the brain parenchyma.
Within a 1-month period, we surgically treated 2 patients with cerebral cavernous malformations located near Broca’s area. In both patients, the cerebral cavernous malformations were symptomatic; thus, surgical removals were recommended.
In an attempt to remove the lesions with minimal invasiveness, we constructed and utilized preoperative 3D fusion images for surgical simulation. Surgical simulations were performed for the following purposes: to identify a surgical route to the lesions, using sulci and gyri as landmarks, to design a minimally invasive procedure for craniotomy and skin incision, and to identify the anatomical location of Broca’s area (using the inferior frontal gyrus as a marker).
MR imaging (GE Medical Systems) and CT scanning (Toshiba Medical systems) data sets were transferred to Ziostation (Ziosoft, Tokyo, Japan), a 3D workstation. Using the workstation, a 3D model of the brain surface and arteries was reconstructed from the MR images, and a 3D model of the skull, hematoma, and skin was reconstructed from CT scans. Use of Ziostation allows neurosurgeons to rotate or magnify 3D fusion images. Additionally, each element (the skull, brain, or arteries) can be dissected on the workstation so that a neurosurgeon can preoperatively simulate surgical procedures.
A 52-year-old right-handed woman with no prior history of neurological symptoms was referred to our hospital with chief complaints of aphasia and headaches and no sign of both extremities weakness. These symptoms had developed suddenly 1 week before she was admitted to the hospital. CT images revealed intracerebral haemorrhage (maximum 3.5 cm in diameter) in the left frontal lobe (Figures
MR images and CT scans of Case 1. (a) and (b), preoperative MR images; (c) and (d), preoperative CT scans; (e) and (f), postoperative CT scans.
Cerebral angiography revealed a contralateral unruptured aneurysm in the M1 region (not shown). On the basis of the preoperative MRI findings (Figures
Case 1. (a)–(e), 3D fusion images on the workstation; (c), anatomical estimation of Broca’s area (
The patient underwent craniotomy under general anaesthesia 1 week after the onset of haemorrhage. A straight skin incision was made behind the hairline, and a bone flap was removed to reveal the preoperatively targeted sulcus (Figure
A CT scan obtained after the surgery confirmed complete removal of the hematoma (Figures
A 23-year-old right-handed woman had experienced refractory ICH in the left frontal lobe 3 times within 2 years and was referred to our hospital. A CT scan revealed a small high-density region in the left frontal lobe that was confirmed to be a subacute ICH (maximum 2.0 cm in diameter) (Figures
MR images and CT scans of Case 2. (a) and (b), preoperative MR images; (c) and (d), preoperative CT scans; (e) and (f), postoperative CT scans.
A cerebral angiography revealed no abnormalities. On the basis of preoperative MRI findings (Figures
Case 2. (a)–(e), 3D brain images on the workstation; (g)–(i), intraoperative pictures; (j)–(l), results of fMRI. The speech centre (orange regions) was located posterior to the lesion; (f), plain craniogram obtained after surgery; (g), image taken just after opening the dura to identify the preoperatively planned sulci and gyri; (h), image taken at the time of corticotomy; (i), image taken after haemostasis was accomplished.
Following surgical simulation, the patient underwent a craniotomy under general anaesthesia. A curvilinear incision was made, and it ended just behind the hairline. A bone flap was then removed to reveal the preoperatively targeted sulcus. A cross-shaped opening was made in the dura (Figure
A CT scan obtained after surgery confirmed complete removal of the hematoma (Figures
The management of cerebral cavernous malformations typically includes 2 options: surgery or conservative observation. One of the most important aspects in treating these lesions is the appropriate selection of patients for surgery because most of these intracranial malformations are benign [
Functional mapping and/or neuronavigation have proven to be useful tools during surgery in patients affected by symptomatic cerebral cavernous malformations located near eloquent areas [
A relatively new method for functional brain mapping, nTMS, has gained popularity in the field of brain mapping [
Our concept of preoperative surgical simulation using a brain 3D fusion image partly resembles MRI-based corticotopography (MRI-bct) as described by Esposito et al. [
In the present cases, we adopted a transsulcal microsurgical approach [
Here, we report 2 cases of patients with cerebral cavernous malformations near Broca’s area. With the aid of presurgical simulation using 3D fusion images, lesions in both the cases were surgically removed without neurological sequel. The main advantages of our technique are that it offers the ability to simulate surgical strategy and to utilize brain gyri and sulci as surgical landmarks. Furthermore, in contrast to other intraoperative techniques, this method can aid in shortening the duration of surgery.
None of the authors has any personal financial or institutional interest in any of the drugs, materials, or devices described in this paper.
The authors declare that there is no conflict of interests regarding the publication of this paper.