can also be useful when simulating endoscopic procedures such as approaching the orbit through the paranasal sinuses.

Useful tools empowering a computer-aided surgery system may facilitate segmentation, registration, visualization, mensuration, and surgery simulation. Several of these tools are available in our computer-aided neurosurgery systems, BrainBench (11) and VIVIAN (10). The patient-specific multimodal data along with individualized human body model can be visualized and manipulated, allowing the surgeon to pick a structure of interest (Fig. 2b) or remove a tumor (Fig. 2c) and look at it from any viewpoint, while its surrounding structures are revealed. A simulator should be able to support a wide range of cutting and drilling accessories for bony dissection and reconstruction. An example in Fig. 2d illustrates craniotomy simulated by a virtual drill removing bone and tissue in a volumetric CT image.

FUTURE COMPUTER-AIDED ORBITAL SURGERY

Based on the current trends and advances in underlying component technologies, we predict that the future computeraided surgical systems will:

becoming robust, safe, versatile, more intelligent and autonomous, and hopefully less expensive;

be highly miniaturized and use MEMS and nanotechnology;

be voiceand gesture-enabled with extensive vocabularies; and

have vision, touch, smell, and locomotion.

The future computer-aided orbital surgery system must also support multiple surgical approaches (2) as well as different types of interventions including microsurgery, endoscopy, endovascular procedures, and telepresence. In addition, the system should provide skill assessment by comparing the actual intervention with the database of accepted and unaccepted surgical approaches.

Technological advancements keep minimizing trauma to the patient and maximizing surgical outcome. The surgeon is

equipped today with a growing arsenal of instruments and multiple sources of information. At the same time, this powerful instrumentarium and vast amount of information impose new constraints and increase the surgeon’s physical and mental workload. Therefore, we envisage that this current phase of exploiting dramatic technological advancements will be succeeded by a new phase focused more on conceptual changes. These changes will be needed to preserve the central role of the surgeon while freeing him or her from the technol- ogy-oriented overload.

To achieve this goal, we have proposed an integrated and intelligent environment for future neurosurgery (13), and we envisage that a similar kind of environment will also be suitable for treatment of orbital disease. In our opinion, the surgeon of the future will need a single assistant integrating all necessary instrumentation and sources of information. This intelligent assistant should perform two major functions: 1) DO it and 2) TELL or SHOW me. We therefore call this yet-to-be-built tool, DOTELL (13). The dotell controls all pre-, intra-, and postoperative information; performs all routine operations; makes technology transparent to the surgeon; and controls all instruments used in the operating room. It is an intelligent tool with robotic capabilities that integrates information infrastructure, knowledge-based decision support, imaging systems, and therapeutic modalities as well as provides monitoring and advice and performs actions.

The dotell has three major units, input, digital central nervous system, and output. The input unit interfaces with the patient, data, instruments, human body models, operating room, network, and surgeon. The output unit is linked to the patient, instruments, operating room, network, and surgeon and contains three main modules (DO, TELL, and SHOW). The digital central nervous system controls all inputs and outputs, and processes information.

The dotell is voiceand gesture-enabled, and contains a natural speech recognition analyzer and a feature-based gesture analyzer. This allows the surgeon to control the dotell in a natural and intuitive way.

The dotell accesses all preoperative data, including morphological, functional, pathological, and vascular scans, and registers them mutually providing a single, multimodal volumetric image. During the procedure, the preoperative scans are actualized with the intraoperative scans and the surgical situation is monitored. The dotell has access to deformable models integrating anatomical, functional, and biophysical maps of the human body. It registers these models with the patient-specific data and plans the procedure.

The DO module of the dotell’s output unit is a robotic system dealing with the patient and a variety of surgical instruments. It contains multiple robotic synchronized arms, each with arbitrary motion, precise force control, and a wide range of motion and force scaling. The robotic system can operate on the patient autonomously under the surgeon’s supervision or guidance. The TELL module contains a voice generator and generates replies to the surgeon’s queries. The SHOW module, which provides stereoscopic display, may use techniques as discussed earlier. To free the surgeon from wearing any devices, we equip the dotell with digital holography and voice recognition capabilities. Dotell, as a surgeon’s personal assistant, is highly customizable. A personalized dotell can be customized to know a surgeon’s protocols and preferred settings, recognize his or her speech patterns and gesture preferences, and collect cases and prepare studies.

SUMMARY

The current technological breakthroughs mark just the beginning of dramatic changes forthcoming to computer-aided surgery. They will further be accelerated by introducing new computer technologies such as molecular computing, making computers of orders of magnitude more powerful and far cheaper than today’s machines.

Extensive efforts of multidisciplinary teams with active involvement of clinicians and researchers are necessary to develop and validate realistic modeling techniques, build accurate orbital models, and develop and test suitable orbital simulators. New conceptual solutions will be needed to exploit

technology benefits and preserve the central role of the surgeon while at the same time freeing him or her from the technology overload.

ACKNOWLEDGMENTS

Several staff from my laboratory contributed to this work, among many others—Yu Chun Pong, Chui Chee Kong, Xu Meihe, Ng Hern, Luis Serra, Ralf Kockro, and Anthony Fang.

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