Quantitative measures of performance in microvascular anastomoses.

OBJECTIVE: Methods of evaluating surgical performance are mainly subjective. This study introduces a method of evaluating surgical performance using a quantitative analysis of tool tip kinematics. METHODS: One experienced surgeon performed eight rat microvascular anastomoses over a 2-day interval. An optoelectronic motion analysis system acquired tool tip trajectories at frequencies of 30 Hz. On the basis of a hierarchical decomposition, the procedure was segmented into specific surgical subtasks (free space movement, needle placement and knot throws) from which characteristic measures of performance (tool tip trajectory, excursion and velocity) were evaluated. Comparisons of performance measures across each procedure were indexed (D scale) using the Kolmogorov-Smirnov statistic. RESULTS: Despite the marker occlusions, tool tip data were obtained 92 +/- 7% (mean +/- SD) of the time during manipulation tasks. Missing data segments were interpolated across gaps of less than 10 sample points with errors less than 0.4 mm. The anastomoses were completed in 27 +/- 4 min (range 20.5-31.4 min) with 100% patency. Tool tip trajectories and excursions were comparable for each hand, while right and left hand differences were found for velocity. Performance measures comparisons across each procedure established the benchmark for an experienced surgeon. The D-scale range was between 0 and 0.5. CONCLUSION: The study establishes a reproducible method of quantitating surgical performance. This may enhance assessment of surgical trainees at various levels of training.

Robotics in neurosurgery.

Technological developments in imaging guidance, intraoperative imaging, and microscopy have pushed neurosurgeons to the limits of their dexterity and stamina. The introduction of robotically assisted surgery has provided surgeons with improved ergonomics and enhanced visualization, dexterity, and haptic capabilities. This article provides a historical perspective on neurosurgical robots, including image-guided stereotactic and microsurgery systems. The future of robot-assisted neurosurgery, including the use of surgical simulation tools and methods to evaluate surgeon performance, is discussed.

Expression of T-type calcium channel splice variants in human glioma.

In humans, three isoforms of the T-type (Ca(v)3.1) calcium-channel alpha(1) subunit have been reported as a result of alternate splicing of exons 25 and 26 in the III-IV linker region (Ca(v)3.1a, Ca(v)3.1b or Ca(v)3.1bc). In the present study, we report that human glioma express Ca(v)3.1 channels in situ, that splicing of these exons is uniquely regulated and that there is expression of a glioma-specific novel T-type variant (Ca(v)3.1ac). Seven human glioma samples were collected at surgery, RNA was extracted, and cDNA was produced for RT-PCR analysis. In addition, three glioma cell lines (U87, U563, and U251N), primary cultures of human fetal astrocytes, as well as adult and fetal human brain cDNA were used. Previously described Ca(v)3.1 splice variants were present in glioma samples, cultured cells and whole brain. Consistent with the literature, our results reveal that in the normal adult brain, Ca(v)3.1a transcripts predominate, while Ca(v)3.1b is mostly fetal-specific. RT-PCR results on glioma and glioma cell lines showed that Ca(v)3.1 expression in tumor cells resemble fetal brain expression pattern as Ca(v)3.1bc is predominantly expressed. In addition, we identified a novel splice variant, Ca(v)3.1ac, expressed in three glioma biopsies and one glioma cell line, but not in normal brain or fetal astrocytes. Transient expression of this variant demonstrates that Ca(v)3.1ac displays similar current-voltage and steady-state inactivation properties compared with Ca(v)3.1b, but a slower recovery from inactivation. Taken together, our data suggest glioma-specific Ca(v)3.1 gene regulation, which could possibly contribute to tumor pathogenesis.

Robot-assisted neurosurgery.

Technological advances in the modern operating room have pushed neurosurgeons to the limits of their dexterity and stamina. Motion scalers and tremor filters on robots permit unprecedented precision of tool manipulation, upgrading the human hand, and closing the deftness deficit. The evolution of neurosurgical robots from stereotactic systems to hybrid systems capable of both stereotaxy and microsurgery is examined. The future of robot-assisted neurosurgery, including expanded tool sets and the prospect of semi-autonomous surgery, is discussed.

Surgical robotics: a review and neurosurgical prototype development.

PURPOSE: The purpose of this article is to update the neurosurgical community on the expanding field of surgical robotics and to present the design of a novel neurosurgical prototype. It is intended to mimic standard technique and deploy conventional microsurgical tools. The intention is to ease its integration into the "nervous system" of both the traditional operating room and surgeon. CONCEPT: To permit benefit from updated intraoperative imaging, magnetic resonance imaging-compatible materials were incorporated into the design. Advanced haptics, optics, and auditory communication with the surgical site recreate the sight, sound, and feel of neurosurgery. RATIONALE: Magnification and advanced imaging have pushed surgeons to the limit of their dexterity and stamina. Robots, in contrast, are indefatigable and have superior spatial resolution and geometric accuracy. The use of tremor filters and motion scalers permits procedures requiring superior dexterity. DISCUSSION: Breadboard testing of the prototype components has shown spatial resolution of 30 microm, greatly exceeding our expectations. Neurosurgeons will not only be able to perform current procedures with a higher margin of safety but also must speculate on techniques that have hitherto not even been contemplated. This includes coupling the robot to intelligent tools that interrogate tissue before its manipulation and the potential of molecular imaging to transform neurosurgical research into surgical exploration of the cell, not the organ.

Aneurysm clips.

This communication outlines the development of aneurysm clips, from those originally used by Walter Dandy to those in use today. The history is rich, with many contributions from neurosurgical pioneers and innovators. As a result, the modern neurosurgeon has a wide selection of biocompatible aneurysm clips from which to choose, clips that have known closing pressures and various sizes and shapes, as well as a selection of clip applicators that do not obstruct the surgical field.

From microscopic to astronomic, the legacy of Carl Zeiss.

IN 1846, CARL ZEISS established a workshop to make lenses for microscopes, cameras, binoculars, and astronomical observatories. He was a master craftsman and was intolerant of any flaw, destroying microscopes with only minor inaccuracies. His relentless pursuit of perfection brought him into contact with a brilliant physicist, Ernst Abbe. Zeiss combined Abbe's new optical laws with his own technical skills; together, they created a colossus. Their company came to be known not only for exquisite technical standards but also for labor relations that were and remain progressive. The development of microneurosurgery was aided by the active participation of Carl Zeiss, Inc. The history of this company provides a lesson in the power of entrepreneurship and the benefits to humanity that can accrue from a fruitful partnership between medical science and industry.