| BackgroundNeurosurgery is one of the most difficult and the finest surgical operations. The microneurosurgery plays the significant role in the neurosurgery department of 21st century. Choosing the best operative approach according to the patient's condition and carrying out the individual operation are necessary for the neurosurgeon. For the development of the neurosurgery, it is essential to carry out accurate, direct-viewing, the individual operation plan and the mimic surgery.The surgical plan system based on virtual reality(VR)image is an advanced medical imaging system which employs CT or MR data to produce a kind of three-dimensional (3D) VR environment, which could be randomly rotated, dragged, assisted with cutting isolated and fused etc. Mimic operation could be performed using different tools, which could reveal clearly the operation area and anatomic structure directly.The surgical plan system based on VR image has prevailed in the neurosurgical centers of some developed countries, but is still at its infant stage in China. To investigate the clinical practice of Dextroscope system used in the neurosurgery department, we choose ruptured intracranial aneurysms and skull base tumor as the main goal, especially to evaluate the value of virtual reality techniques in diagnosing aneurysms, and the treatment of craniotomy clipping of intracranial aneurysm and the skull base tumors.Whether this system enhances the diagnosis rate, raise the neurosurgery level, reduce complication and the mortality is our issue. We also assess the feasibility in the application of clinical practice.Chapter 1 virtual reality techniques in diagnosingthe intracranial aneurysm at the early stageIntroduction about the Dextroscope systemDextroscope system is one of surgery plan systems based on virtual reality techniques, designed by the company of Singapore VI(Volume Interactions). This system is composed of the Dextroscope hardware system and the RadioDexter software system.RadioDexter system is the combined application of virtual imaging techniques and three-dimensional computed tomographic angiography, which employs CT or MR data to produce a kind of three-dimensional (3D) VR environment. Surgeons may manipulate the 3D virtual medical images with their hands interactively and directly. RadioDexter can slice the image that enables surgeon to have a clear understanding about surgery region with various part of structure.We compared the virtual reality techniques with the DSA examination to explore its advantage and disadvantage in the diagnosis of ruptured intracranial aneurysms.Objective The purpose of this study was to evaluate the clinical value of using 3D-CTA combined with the RadioDexter plan system based on VR image to screen and diagnose ruptured intracranial aneurysms. Compared with the DSA examination, we explore the clinical value of the virtual reality techniques in diagnose of ruptured intracranial aneurysms at the early stage.Materials and MethodsA total of 80 SAH patients was treated in Zhujinag hospital of Southern Medical University during December 2005 and December 2006. All the patients received 3D-CTA and Dextroscope examinations, and then DSA examination. The patients with negative results received the examination for a second time one month later, to evaluate the clinical value of using 3D-CTA combined with VR on the diagnosis of the intracranial aneurysms.ResultsA total of 73 aneurysms were detected in 68 of the 80 cases by 3D-CTA and Dextroscope examination. Among the 68 patients, there were 2 patients with arteriovenous malformation(AVM), 4 patients with multiple cerebral aneurysms. Among the other 12 patients, 5 cases were diagnosed as AVM, 2 cases as moyamoya disease, and the rest 5 cases were detected without positive findings. 68 patients received DSA examination to detect no false positive case.5 cases also had no positive findings after DSA examination, but the 3D-CTA and Dextroscope examination on these cases one month later found 2 aneurysms in 2 cases, which were confirmed by the DSA examination. The other 3 cases detected to be free of aneurysms again showed negative results in the DSA examination. As for the 68 aneurysms definitely diagnosed, 3D-CTA showed their location, size and profile, especially their anatomic relation to the parent artery and adjacent structures well . The 3D virtual images produced by the virtual imaging system were clear and vivid, and could be randomly rotated, dragged, isolated and fused et al. The virtual intravascular endoscope could be applied to observe thrombosis, calcification and separation and so on in the inner wall of blood vessels and tumor cavity, and clearly exhibit the site of the aneurysm neck, provide applicable data for surgical operations. All the patients in this study had undergone DSA examination. At the same time, part of them received rotational 3D DSA. It also detected no false positive and no negative findings after 3D-CTA and Dextroscope examination. DSA could clearly show their location, size profile and parent artery. However, DSA could not show the anatomic relation between artery and skull. Compared with 3D-CTA and Dextroscope images, 3D- Reconstruction data were less clear, precise and vivid.The diagnosis results of 80 patients at the first time with 3D-CTA : sensitivity 97.1%(68/70), specificity 100%(10/10); comprehensive results of twice 3D-CTA diagnosis : sensitivity 100%(70/70), specificity 100%(10/10). The results were completely consistent with the DSA diagnosis.Conclusions1. As a kind of technology for diagnostic imaging developed in recent years, 3D-CTA has been winning more and more attention in diagnosing and treating intracranial aneurysms. It is not convenient, fast, inexpensive and almost noninvasive by application, so,3D-CTA is the first choice of imaging examination for ruptured intracranial aneurysms, especially the emergency operation, examinations of post -operation and follow-up.2. Compared with the conventional planar 3D images, 3D-CTA images could show the aneurysms and their adjacent blood vessels and skulls more clearly and directly. And observe thrombosis, calcification and separation and so on in the inner wall of blood vessels and tumor cavity, but the blood flow can not be detected by 3D-CTA. It cannot show the aneurysms affected by cerebral venous sinus.3. Dextroscope is easier than 3D-CTA to manipulate. 3D-CTA show their location, size and profile, especially their anatomic relation to the parent artery and adjacent structures well. The 3D virtual images produced by the virtual imaging system are clear and vivid, and could be randomly rotated, dragged, isolated and fused etc .Compared with 3D-CTA, it can clearly show the anatomic relation between artery and skull.4. The virtual intravascular endoscope could be applied to observe thrombosis, calcification and separation and so on in the inner wall of blood vessels and tumor cavity, and clearly exhibit the site of the aneurysm neck. The body of aneurysm, maybe provide the position of ruptured aneurysms.5. The Dextroscope system based on VR techniques elevates the accuracy of diagnosis. Dextroscope system can provide surgeon with unprecedented direct-viewing, accurate, the clear aneurism, the adjacent blood vessels and the osseous structure images, which provide useful information for endovascular treatment and craniotomy.Chapter 2 Virtual reality technology in the microsurgery of aneurysmsObjectiveTo study whether the Dextroscope virtual reality surgical plan system can improve the quality of surgery, reduce the risk and improve the prognosis, assess the clinical value of virtual reality technology in the craniototmy clipping of intracranial aneurysm.Materials and methods A total of 106 patients planning to receive craniotomy clipping of intracranial aneurysm were selected from Fuzhou General Hospital of Nanjing Military Area Command during January 2007 and September 2007. All the patients were diagnosed aneurism after 3D-CTA and (or) DSA examinations and were randomly divided into operation planning group(51 cases) and the control group(56 cases). Among the 51 cases of planning group, 21 cases were excluded because of without 3D-CTA examination, all of the other 30 cases received pre-operation planning and simulation operation.Virtual reality surgery system of Dextroscope hardware and RadioDexter1.2 software systems (VI, Singapore) were adopted. The raw data of volumetric 3D-CTA scan for all patients were imported into the above systems and then loaded into the VR environment to perform virtual 3D reconstruction of the brain blood vessels and skulls and reveal their images; different instruments provided by the operating system were included in zooming, measuring, isolating and splitting procedures to display the aneurysms and the anatomic relation to their parent arteries and adjacent structures; The virtual intravascular endoscope could be applied to observe thrombosis, calcification and separation and so on in the inner wall of blood vessels and tumor cavity, and clearly exhibit the site of the aneurysm neck, the body of aneurysms.After observing anatomic structure, surgical assessment and plan were conducted. The surgical plan includes the approach, the body posture, the important procedures, emergency preparation. Then, surgical planning was mapped out and virtual surgery was performed. The actual surgery should be taken according to the surgery plan as possible, recording the differences and the same points between actual surgery and mimic surgery. All patients' Glasgow outcome scores (GOS) were analyzed at the third month to judge prognosis.Results3D-CTA images could show the aneurysms, the shape, the neck of aneurysms, the parent artery and skulls more clearly and directly. Precisely measure the size, shape, the cyst of aneurysms, and anatomic landmark. It formulates the preoperative assessment and individual surgical plan and allows the option of preoperative rehearsal according to the operation plan, such as craniotomy.The operation group performs the surgery according to preoperative plan. What we observe in the process of operation is the same with the simulated surgery. Compared with the control group, the proportion of the breakage aneurism, the volume of blood, the period of surgery and the hospital day was smaller. Statistics shows that volume of blood, and the period of surgery is significantly different between the two groups. Aneurysm breakage rate and the average days in hospital were non-significance. The complication rate of operation group was lower than that of control group .but differences between two groups were non-significant. The prognosis rate of surgery group was higher than that of control group, but differences between two groups were statistically non-significant.Conclusions:1. Using the VR operation system can conduct 3D reconstruction of the aneurysms. Which show the aneurysms and adjacent structures clearly and vivid. Formulate individual plan, perform the simulated operation according to the surgical plan, which can make the surgeon know what will happen in advance.2. The operation plan is available based on the VR operation system. What we observe in actual surgery is highly consist with preoperative rehearsal. The simulated operation can provide guidance and assistance in actual operation. 3. The application of virtual reality surgery system can improve the quality of surgery, reduce the risk and improve the prognosis, significantly improve the result of craniotomy clipping of intracranial aneurysm.Chapter 3 Virtual reality technology in microsurgery of skull base tumorsObjectiveFor the patients with skull base tumors using Dextroscope system to make auxiliary diagnosis and the operation, which help formulate individual plan, perform the simulated operation according to the surgical plan. Demonstrate the differences of anatomic structure between the simulated surgery and the actual surgery, and assess the clinical value of virtual reality technology for skull base tumors.Materials and methodsA total of 39 patients (operation group=19, surgical group=20 ) with the tumors of skull base were selected from Fuzhou General Hospital of Nanjing Military Area Command during June 2007 and September 2007. Use the Dextroscope system to conduct 3D reconstruction in VR environment, which can show the relationship between tumors and other important structures. Observe the shape and adjacent structures of the tumor, and then carefully record the important anatomical data. Operation program was conducted based on the preoperative assessment to perform the stimulated surgery. It is necessary to rectify the operation plan if it changes. Differences between simulated surgery and actual condition should be carefully observed, and to validate whether the program is appropriate. Extent of lesion-resection, volume of blood and the period of surgery also should be registered. Secondary CT or MR was necessary to get the information about the extent of tumor-resection. After that, complication situation, the period of staying in the hospital, the days in the ICU and all fees should be written down when the patientswere dismissed. The differences of those indexes were compared.ResultsThe 19 cases were adopted 3D-reconstruction in virtual reality environment. After the reconstruction, different structure's images can combine each other at will. The system can also randomly carry those pictures to revolve or cut. Every section can be randomly observed. Different instruments provided by the operating system were included in zooming, measuring, isolating and splitting procedures to display the location of tumor, shape, nerve, blood vessels, and adjacent structures. Every patient underwent preoperative assessment, which includes the body posture, the flexion and extension, the operative approach, the skin incision, the drilling position, the size of bone flaps, the incision of dura mater, extent of lesion-resection and emergency plan in the process of operation et al. Operative procedures should be performed according to the simulated surgical plan. All the operation is same as preoperative plan. At the same time, approach, operation exposure were satisfied, and the results of all operations were good. Nobody died in the process of operation.Compared with the control group, the period of the operation, the volume of blood was smaller. Statistics showed that volume of blood, and the period of surgery was significantly different between the two groups. The complication rate of operation group was lower than that of control group, but differences between two groups were non-significant. Compared with control group, the length of stay and the days in the ICU were decreased, and all fees were lower in operation group, but the differences between the two groups were statistically non-significant.Conclusions1. Using the VR operation system can conduct 3D reconstruction of the skull base tumors, which show the location of tumor, shape, blood vessels, nerve and adjacent structures clearly and vivid. And demonstrate more 3D information for the surgeon. After formulating the preoperative assessment and individual plan, it is time to perform the simulated operation according to the surgical plan, which supplies best approach for surgeon in actual operation.2. The operation plan based on VR techniques is available. What we observe in actual surgery is highly consist with preoperative rehearsal. The simulated operation can provide guidance and assistance in actual operation.3. The application of virtual reality surgery system not only reduces the blood loss for the patients of skull base tumors, shorten the period of operation, but also can decrease the risk.4. The application of virtual reality surgery system has not increase the burden.
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