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The Evolution of Neurosurgical Instrumentation
Forum
Robert F. Spetzler, M.D. Director, Barrow Neurological Institute (BNI) J.N. Harber Chair of Neurological Surgery at BNI Chairman and President, Barrow Neurosurgical Associates, Professor of Surgery Section of Neurosurgery, University of Arizona College of Medicine
The Evolution of Neurosurgical Instrumentation Robert F. Spetzler and Rodney Samuelson
T
hroughout history, innovation in surgical instrumentation has gone hand-in-hand with advances in neurosurgical technique. The founders of our specialty designed numerous surgical instruments to better address the surgical challenges that they encountered. Some instruments were found to so perfectly serve their function that they are still in common use today. Such tools include the Cushing periosteal elevators, Penfield dissectors, and Yasargil microscissors. Typically, as an operation proceeds in depth and complexity, the instruments used are progressively more modern in design. However, the absence of a “universal set” of craniotomy instruments demonstrates that individuality is a second principle of surgical innovation. Different surgeons may solve similar problems through surprisingly diverse means. Although many neurosurgeons practicing today have developed their own instruments, it is difficult to determine which designs will become the classic instruments of tomorrow. Critical appraisal by independent neurosurgeons during a period of time is needed to establish the true merit of a surgical instrument. During the past 20 years, new developments in instrumentation have enabled our treatment of many complex lesions in the posterior fossa and brainstem, including arteriovenous malformations, cavernous malformations, and skull base tumors. For example, separating solid tumors from the surrounding brainstem or from a bony attachment often requires more force than can be delivered with common microdissectors. Yet, the surgical corridors are far too narrow to introduce standard instruments. Therefore, a set of microdissectors with intermediately sized handles have been produced. They respond equally well to light touch or graduated pressure. The tips have a shallow disk that effectively works its way through the cleavage plane. These instruments are available in three sizes and three angles to provide many options for resecting deeply situated lesions.
From the Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA To whom correspondence should be addressed: Robert F. Spetzler, M.D. [E-mail: [email protected]]
Brainstem cavernous malformations, in particular, are difficult to treat because they are located at extreme depths and the working space often provides only a single trajectory for resection. Therefore, rotatable stem microcup forceps with straight, 45-degree, and 90degree tips can be used to improve visualization while reaching any portion of the resection bed from a common entry point. Adequate visualization of the working area is also essential. Bright tungsten light penetrates the deep and narrow corridors, and now the surgical microscope has been further refined by linking image-guided navigation with the position of the microscope. This advance allows real-time, continuously updated information on position, which is immensely valuable when localizing deep lesions. However, the limits of visualization are being pushed further by the embedding of a small light into the bipolar shaft or into the tip of the malleable suction catheter. This light illuminates areas that even the brightest microscope cannot reach. A hand-held endoscope currently in development may further augment the view through the microscope. For deep lesions, the use of a rotating drill to expand the working corridor in the immediate proximity of vital neurologic or vascular structures can be hazardous. Therefore, ultrasonic aspirators now combine high-frequency torsional vibration with specially designed serrated tips. This design allows precise bone removal along one surface of the ultrasonic aspirator while minimizing danger to nearby structures. Keeping the bipolar tips from sticking to tissue during complex vascular operations is another key to safe and effective surgery. High temperatures, fragments of burnt tissue, and worn or damaged bipolar surfaces all contribute to this problem. Therefore, a new bipolar forceps with a high heat-diffusion coefficient has been developed. It incorporates a smooth, broad surface with a one-time use, nonstick coating. For surgery involving arteriovenous malformations and arteriovenous fistulas, two separate bipolar forceps are
Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter © 2011 Elsevier Inc. All rights reserved.
Citation: World Neurosurg. (2011) 75, 1:20-21. DOI: 10.1016/j.wneu.2010.12.029
20
www.SCIENCEDIRECT.com
WORLD NEUROSURGERY, DOI:10.1016/j.wneu.2010.12.029
FORUM ROBERT F. SPETZLER AND RODNEY SAMUELSON
NEUROSURGICAL INSTRUMENTATION
used. This strategy allows one to be wiped carefully and stored in an ice water bath while the other is in use. With proper technique, this bipolar has eliminated the problem of tissue adherence during surgery. The surgical laser has also undergone many cycles of improvement over the years. Recent advances have produced a hand-held, hollow-core CO2 laser that can be manipulated under the microscope like any other surgical instrument. The depth of tissue ablation is easily controlled by adjusting the laser’s power, distance from the lesion, and duration of application. This flexibility offers the advantage of no-touch dissection with simultaneous coagulation of the pial microvasculature. Therefore, this surgical laser is now frequently utilized during the resection of brainstem and intramedullary spinal cord lesions. Although each of these advances in surgical instrumentation have improved our success in treating complex posterior fossa lesions, it is clear that other advances in medicine have reduced the need for this type of surgery. In the future, reduced patient volume will likely
result in the consolidation of both surgical technique and instrumentation. Complex cases will be concentrated at referral centers with highly specialized surgeons and high-cost, high-end instrumentation. This trend may lead to less variety in commercially available instruments. However, there will be more custom fabrication and more one-time use instruments that take advantage of materials that cannot withstand repeated sterilization. The impetus is on future generations of neurosurgeons to improve our current level of surgical refinement. Individuality and reflection in the setting of reduced volume will have its own effect on the evolution of neurosurgical instrumentation.
Citation: World Neurosurg. (2011) 75, 1:20-21. DOI: 10.1016/j.wneu.2010.12.029 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter © 2011 Elsevier Inc. All rights reserved.
NASA astronaut Rick Mastracchio, STS-131 mission specialist, participates in a seven-hour, 26-minute EVA (extravehicular activity) as construction and maintenance continue on the International Space Station. Credit: NASA.
WORLD NEUROSURGERY 75 [1]: 20-21, JANUARY 2011
www.WORLDNEUROSURGERY.org
21
Robert F. Spetzler, M.D. Director, Barrow Neurological Institute (BNI) J.N. Harber Chair of Neurological Surgery at BNI Chairman and President, Barrow Neurosurgical Associates, Professor of Surgery Section of Neurosurgery, University of Arizona College of Medicine
The Evolution of Neurosurgical Instrumentation Robert F. Spetzler and Rodney Samuelson
T
hroughout history, innovation in surgical instrumentation has gone hand-in-hand with advances in neurosurgical technique. The founders of our specialty designed numerous surgical instruments to better address the surgical challenges that they encountered. Some instruments were found to so perfectly serve their function that they are still in common use today. Such tools include the Cushing periosteal elevators, Penfield dissectors, and Yasargil microscissors. Typically, as an operation proceeds in depth and complexity, the instruments used are progressively more modern in design. However, the absence of a “universal set” of craniotomy instruments demonstrates that individuality is a second principle of surgical innovation. Different surgeons may solve similar problems through surprisingly diverse means. Although many neurosurgeons practicing today have developed their own instruments, it is difficult to determine which designs will become the classic instruments of tomorrow. Critical appraisal by independent neurosurgeons during a period of time is needed to establish the true merit of a surgical instrument. During the past 20 years, new developments in instrumentation have enabled our treatment of many complex lesions in the posterior fossa and brainstem, including arteriovenous malformations, cavernous malformations, and skull base tumors. For example, separating solid tumors from the surrounding brainstem or from a bony attachment often requires more force than can be delivered with common microdissectors. Yet, the surgical corridors are far too narrow to introduce standard instruments. Therefore, a set of microdissectors with intermediately sized handles have been produced. They respond equally well to light touch or graduated pressure. The tips have a shallow disk that effectively works its way through the cleavage plane. These instruments are available in three sizes and three angles to provide many options for resecting deeply situated lesions.
From the Division of Neurological Surgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, Arizona, USA To whom correspondence should be addressed: Robert F. Spetzler, M.D. [E-mail: [email protected]]
Brainstem cavernous malformations, in particular, are difficult to treat because they are located at extreme depths and the working space often provides only a single trajectory for resection. Therefore, rotatable stem microcup forceps with straight, 45-degree, and 90degree tips can be used to improve visualization while reaching any portion of the resection bed from a common entry point. Adequate visualization of the working area is also essential. Bright tungsten light penetrates the deep and narrow corridors, and now the surgical microscope has been further refined by linking image-guided navigation with the position of the microscope. This advance allows real-time, continuously updated information on position, which is immensely valuable when localizing deep lesions. However, the limits of visualization are being pushed further by the embedding of a small light into the bipolar shaft or into the tip of the malleable suction catheter. This light illuminates areas that even the brightest microscope cannot reach. A hand-held endoscope currently in development may further augment the view through the microscope. For deep lesions, the use of a rotating drill to expand the working corridor in the immediate proximity of vital neurologic or vascular structures can be hazardous. Therefore, ultrasonic aspirators now combine high-frequency torsional vibration with specially designed serrated tips. This design allows precise bone removal along one surface of the ultrasonic aspirator while minimizing danger to nearby structures. Keeping the bipolar tips from sticking to tissue during complex vascular operations is another key to safe and effective surgery. High temperatures, fragments of burnt tissue, and worn or damaged bipolar surfaces all contribute to this problem. Therefore, a new bipolar forceps with a high heat-diffusion coefficient has been developed. It incorporates a smooth, broad surface with a one-time use, nonstick coating. For surgery involving arteriovenous malformations and arteriovenous fistulas, two separate bipolar forceps are
Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter © 2011 Elsevier Inc. All rights reserved.
Citation: World Neurosurg. (2011) 75, 1:20-21. DOI: 10.1016/j.wneu.2010.12.029
20
www.SCIENCEDIRECT.com
WORLD NEUROSURGERY, DOI:10.1016/j.wneu.2010.12.029
FORUM ROBERT F. SPETZLER AND RODNEY SAMUELSON
NEUROSURGICAL INSTRUMENTATION
used. This strategy allows one to be wiped carefully and stored in an ice water bath while the other is in use. With proper technique, this bipolar has eliminated the problem of tissue adherence during surgery. The surgical laser has also undergone many cycles of improvement over the years. Recent advances have produced a hand-held, hollow-core CO2 laser that can be manipulated under the microscope like any other surgical instrument. The depth of tissue ablation is easily controlled by adjusting the laser’s power, distance from the lesion, and duration of application. This flexibility offers the advantage of no-touch dissection with simultaneous coagulation of the pial microvasculature. Therefore, this surgical laser is now frequently utilized during the resection of brainstem and intramedullary spinal cord lesions. Although each of these advances in surgical instrumentation have improved our success in treating complex posterior fossa lesions, it is clear that other advances in medicine have reduced the need for this type of surgery. In the future, reduced patient volume will likely
result in the consolidation of both surgical technique and instrumentation. Complex cases will be concentrated at referral centers with highly specialized surgeons and high-cost, high-end instrumentation. This trend may lead to less variety in commercially available instruments. However, there will be more custom fabrication and more one-time use instruments that take advantage of materials that cannot withstand repeated sterilization. The impetus is on future generations of neurosurgeons to improve our current level of surgical refinement. Individuality and reflection in the setting of reduced volume will have its own effect on the evolution of neurosurgical instrumentation.
Citation: World Neurosurg. (2011) 75, 1:20-21. DOI: 10.1016/j.wneu.2010.12.029 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter © 2011 Elsevier Inc. All rights reserved.
NASA astronaut Rick Mastracchio, STS-131 mission specialist, participates in a seven-hour, 26-minute EVA (extravehicular activity) as construction and maintenance continue on the International Space Station. Credit: NASA.
WORLD NEUROSURGERY 75 [1]: 20-21, JANUARY 2011
www.WORLDNEUROSURGERY.org
21