The importance of medical images, which neurosurgeons must observe for surgical planning, is enormous. Neurosurgeons must execute the surgical planning through efficient visualization of the images. Historically, medical image processing techniques have been developed with the major aim of improving accuracy of disease diagnosis (e.g., the presence or absence of lesions). On the other hand, the main aim of surgical planning is to determine the treatment, therefore, medical imaging and surgical planning should be clearly distinguished. The use of virtual reality surgical simulation requires comprehensive judgment and visualization techniques, which reflect the knowledge and experience of the neurosurgeon as well as the optimization of medical image information. We report the virtual reality neurosurgical simulation to clarify the difference between radiological diagnosis and simulation.
Endoscopic endonasal surgery has gained popularity in recent years owing to the availability of panoramic and angled surgical views. Additionally, the introduction of high-definition (HD) imagery with 2D endoscopes has enabled acquisition of clearer images in the surgical view. However, despite these advantages, lack of a stereoscopic view is a drawback of 2D endoscopic surgery. Development of 3D endoscopies is an innovative technical advancement that addresses this limitation. The most widely used 3D endoscopy system in the world is Visionsense VSiii (Visionsense, Philadelphia, PA), which was first used in Japan last year. However, we have begun to use a new 3D HD neuroendoscopy system (Machida Endoscopes) that was developed in Japan ; this system has already been used in more than 50 endoscopic endonasal surgeries. We determined that the stereoscopic view offered by 3D endoscopies is useful during bone drilling and suprasellar manipulation. Many publications have shown no significant difference in surgical outcomes between 2D and 3D endoscopic surgery, thereby making it difficult to assess the clinical significance of 3D endoscopic surgery objectively. However, there is a consensus that 3D endoscopic surgery shortens the learning curve for surgeons. Recently, a 3D conversion technique from conventional 2D images has been developed. Both 3D imaging techniques (3D endoscopy and 3D conversion) for endonasal endoscopic surgery will aid in assessing intraoperative judgment and performing certain operative maneuvers.
We herewith focus on functioning adenomas and incidentalomas with regard to evaluating candidates for surgery on pituitary tumors. As radical or curative therapies are currently not available for functioning adenomas such as growth hormone (GH)-producing tumor (GHoma), adrenocorticotropic hormone (ACTH)-producing tumor (ACTHoma), and thyroid-stimulating hormone (TSH)-producing tumor (TSHoma), operative therapy is the main treatment. In some cases of GHomas, preoperative administration of somatostatin analogs is useful. High insulin-like growth factor-Ⅰ (IGF-Ⅰ) levels that are often observed immediately after surgery (in spite of normalization of GH) are expected to eventually attenuate with postoperative time, and therefore immediate adjuvant treatment is not necessary. Repeat surgery on residual GHomas localized within the sella turcica is useful when the tumor does not extend to outside the cavernous sinus. As radical medication therapy using dopamine agonists is available for prolactinoma, surgical resection is restricted to exceptional cases.
However, medication therapy needs long-term for stabilized management, and surgical resection may have to be executed in cases that experience problems in long-term drug administration, or when tumors develop drug-resistance. In cases of ACTHomas, tumor localization is most critical in performing the surgical intervention. Incidentally found non-functioning pituitary adenomas, especially those with suprasellar extension, may compress the optic chiasm to eventually visual dysfunction. Therefore, surgical intervention is appropriate in these cases. Furthermore, in cases with tumor extension to the anterior cranial base or cavernous sinus, tumor resection becomes difficult, and early treatment is recommended. As for Rathke’s cleft cyst, natural achoresis of cyst is occasionally observed, and the postoperative reaccumulation rate is high, follow-up observations are sufficed so long as pituitary functional impairments are absent. If pituitary function is severely impaired, the damage may become irreversible.
Therefore, surgical intervention may be recommended even when only slight pituitary functional impairment is encountered.
Although craniopharyngiomas are categorized as benign brain tumors, long-term prognoses have not been satisfactory due to their locational difficulties and invasiveness. Conventinally-fractionated radiation therapy is the standard radiotherapeutic approach for residual or recurrent diseases after surgery, which significantly improves not only local progression-free rates but also survival outcomes. However, long-term results for patients treated with modern high-precision radiotherapy techniques have not been sufficiently reported. In this retrospective study, 5-year outcomes of Japanese patients with residual or recurrent craniopharyngioma treated with high-precision radiotherapy were evaluated.
A total of 29 patients with residual or recurrent craniopharyngioma, who were consecutively treated with three-dimensional conformal radiation therapy or streotactic radiation therapy between January 2001 and September 2012, were included in the analyses. The median age was 54 years old (range : 7-78). Five pediatric cases (median : 9 years old, range : 7-15) were included. The number of prior surgeries before radiation therapy was one in 18 cases, two in 9 cases and three in 2 cases. Incomplete resection was performed on 28 cases in the most recent surgery before radiation therapy, while gross total resection was achieved in only one patient. Some sort of pituitary hormone deficiency was observed in 28 (97%) cases before radiation therapy. The clinical target volume (CTV) was created by adding a 0-5 mm margin to the tumor bed. The planning target volume was generated by adding a 3-10 mm margin to the CTV. The median prescribed dose at the isocenter was 54 Gy (range : 50.4-54) in a fraction size of 1.8 Gy.
The median follow-up period after radiotherapy was 73 months (range : 27-191). Local recurrence was observed in 5 cases and ectopic intracranial recurrence was observed in one patient. Five-year local control, progression-free survival and overall survival rates were 85.3% (95% confidence interval [CI] : 65.1, 94.2), 81.4% (95% CI : 60.7, 93.4) and 95.8% (95% CI : 73.9, 99.4), respectively. No radiation-induced acute toxicity was observed. In one patient, thyroid stimulating hormone replacement treatment was required 67 months after radiation therapy. No other instances of radiation-related late toxicity were observed.
High-precision radiation therapy in conventional fractionation could achieve a favorable long-term tumor control rate with minimum complications in Japanese patients with residual or recurrent craniopharyngioma. This approach should therefore be considered as the first-choice option in managing residual or recurrent craniopharyngioma after surgery.
Meningiomas are the most common benign brain tumor. Because most meningiomas are slow growing lesions, patients with meningiomas usually have ample time to determine which treatment they undergo. In order to provide the correct meningioma treatment information and to help patients feel convinced of their own decisions, neurosurgeons should understand the current evidence for best practice meningioma treatment. In this article, the authors summarized the recent evidence regarding the “judgment of whether to treat or not” and “determine how to treat meningiomas”. They focused on the natural history of meningiomas, management for asymptomatic meningiomas, the relationship between the extent of resection and the prognosis in the modern neurosurgical era, radiation therapy for meningiomas, as well as treatment strategies for WHO Grade Ⅱ and Ⅲ meningiomas.
According to the Guideline, an MRI scan is recommended to search for intracranial lesions in cases of new-onset unprovoked seizure. Actually, seizure is a relatively common symptom in lesional cases, such as brain tumor. The possible comorbidity rate of epilepsy and tumor is reported to be 29-60% and 20-35% in meningiomas and metastatic tumors, respectively. And more than 80% of low grade glioma patients suffer from epilepsy, a rate that is even more frequent than in malignant cases (29-49%). Perhaps the tumors with the most well-known clinical pathology of all epileptic tumors are glioneural tumors. These tumors are believed to be epileptogenic by nature, and complete ablation of the epileptogenic area is necessary in any attempt to improve seizure control. On the other hand, the ILAE (International League Against Epilepsy) proposed a new classification for focal cortex dysplasia (FCD) in 2011. Under this classification FCD co-exists with and/or is close to the tumor (FCD Type IIIb). Such new clinical criteria were proposed, because subtle FCD undetectable with MRI could be epileptogenic in some tumor cases. Surgical success relies upon the complete resection of the epileptogenic areas and perfect protection of the functional areas at the same time. Pre-surgical evaluation, such as functional MRI and DTI (diffusion tensor imaging) tractography is required for safe surgery. And moreover, intraoperative mapping of the cortex with stimulating and recording electrodes is now widely employed in the resection of lesions involving or adjacent to the eloquent areas, especially with awake craniotomy.
As for conservative therapy of epilepsy along with brain tumors, there are few prospective studies concerning the choice of antiepileptic drug. Finally, there is no clinical evidence for the prophylactic use of antiepileptic drugs for brain tumor cases without seizure.
Cervical laminoplasty, an excellent operative procedure proposed by Japanese orthopedic surgeons, has been widely accepted by Japanese neurosurgeons. There are several long-term follow-up reports on cervical laminoplasty by orthopedic surgeons, but only a few reports on the procedure have been published by neurosurgeons. In the present study, the follow-up results of cervical laminoplasty performed under the surgical microscope were investigated. Among the 84 patients who underwent double-door laminoplasty between October 2006 and December 2009, 44 patients were analyzed in the study. As to the clinical parameters, the age, gender, Japanese Orthopaedic Association (JOA) score, and dynamic changes in the cervical spine were examined preoperatively and postoperatively.
Of the 44 patients included in the study, 33 were males and 11 were females, and their mean age was 64.1 years, with an age range of 23 to 83 years.
The mean follow-up period was 5.1 years (3-6.8 years). The disorders observed are as follows : 32 patients with cervical spondylosis, 9 patients with ossification of the posterior longitudinal ligament (OPLL), 2 patients with cervical soft disc herniation, and 1 with spinal cord injury. Although the JOA scoring method was slightly different preoperatively (nurse oriented) and postoperatively (patient self-filling), the average JOA score was 11.1 preoperatively and 12.8 postoperatively. The range of cervical motion was reduced by about 35% postoperatively. No serious cervical complication was noticed in the present series. The operative result was confirmed to be satisfactory in the present study compared with other reported studies.
A 55-year-old woman presented with subarachnoid hemorrhage. Digital subtraction angiography (DSA) showed AVF with a varix fed by cervical spine (C) 5 radicular arteries. We performed urgent TAE for the C5 radicular artery with coils followed by direct surgery. The small vessels were intricately wrapped around the C5 nerve root and drained into the varix, which existed between the right C5 ventral and dorsal nerve root. From these operative findings, we diagnosed this lesion as C5 radicular AVF. The varix and surrounding small vessels were coagulated step-by-step, and postoperative DSA showed that the AVF had completely disappeared. Although our initial diagnosis for this patient was spinal dural AVF presented with subarachnoid hemorrhage, we finally diagnosed this lesion as radicular AVF using the intraoperative findings. Radicular AVF looks like spinal dAVF, but is different in anatomical features and symptoms. We can recognize radicular AVF as a differential diagnosis from dAVF by the fistulous point.