J Neurosurg 74:677-679, 1991
Intraoperative protection of cranial nerves and perforating arteries by silicone rubber sheets Technical note MASATO SttlBUYA, M.D., KENICHIRO SUGITA, M.D., AND SHIGEAKI KOBAYASHI, M.D.
Departments of Neurosurgery, Nagoya University, Nagoya, and Shinshu University, Matsumoto, Japan u- The authors describe a technique whereby, during microneurosurgery, vital structures are covered or wrapped with small pieces of silicone rubber sheeting to protect them from intraoperative injury. In this way, perforating arteries located behind a large aneurysm can be covered to avoid their inclusion within the blades of the clip, and the cranial nerves coursing around or through a tumor can be wrapped to protect them from injury by a suction or forceps. By insulating nerves and arteries, this silicone rubber sheet has the added advantage of protecting them from injury due to electrical current of bipolar forceps. The silicone rubber sheet described here is smoother, thinner, and lighter than a cotton pattie. KE~" W o a o s
microneurosurgery
9 silicone rubber sheet
cranial nerve
operative technique
LTHOUGH many kinds of cotton patties are commonly used in the neurosurgical operating field, rubber sheets are also useful in certain situations. A small piece of rubber sheeting was initially described by Ya~argil ~ for use during the microvascular anastomosis of fine cerebral arteries. We discuss the utility of silicone rubber sheets for the protection of critical structures such as cranial nerves and blood vessels during microneurosurgery.
A
Description and Use of Material Sterilized silicone rubber (Silastic) sheets 0.125 mm thick were used. A silicone rubber sheet is preferred to a plain rubber sheet when it must be left in the brain, even temporarily until a second operation, since it causes little tissue reaction. Sheets of various sizes and shapes should be prepared before surgery and can be modified to the appropriate shape. An anchoring thread is tied to the base of the sheet so that it can be easily withdrawn from the depth of the surgical field. When a silicone rubber sheet is not instantly available, a surgical glove can be cut into a variety of different pieces and washed free of lubricating powder prior to use.
J. Neurosurg. / Volume 74/April, 1991
Several techniques illustrating the application of silicone rubber sheet during surgery are listed below.
Protection of Perforating Arteries In operations to clip a large or giant aneurysm, a silicone rubber sheet is useful to protect any perforating vessels coursing under both sides of the aneurysm prior to clip placement. This is particularly important when the aneurysm is so large that both sides cannot be visualized simultaneously in the field afforded by the operating microscope. The rubber sheet allows the blades to slide over the perforating vessels, even when the position of the blades cannot be visualized completely.
Protection of Cranial Nerves A cranial nerve coursing over a tumor may impede removal of the tumor mass and may be subjected to injury. Our approach in such a case is to cover the cranial nerve with a thin silicone rubber sheet where it crosses the tumor. When the nerve lies in the center of the operating field, the sheet is wrapped around the 677
M. Shibuya, K. Sugita, and S. Kobayashi nerve and both ends are closed with small hemoclips so that the sheet will not slide along the nerve. Closing the rubber sheet protects the nerve from accidental injury by suction or forceps during removal of the deeper portion of the tumor. This method is useful for fragile thin nerves such as the first, fourth, sixth, seventh, and eighth cranial nerves, especially when the tumor is firm and the procedure must be carried out in a narrow operating field (Fig. 1).
Protection oJ"Crilical Structure~" 1,)'ore E/eclrica/ Current When a bleeding point behind an important vessel or cranial nerve in a narrow operating field is coagulated with bipolar forceps, the vessel or nerve should be temporarily covered with a rubber sheet. Leakage of electrical current can cause injury to a critical structure when forceps inadvertently touch the nerve or vessel. Prevention ( f Postoperative Adhesions When staged operations are performed for large arteriovenous malformations, we leave sheets of silicone rubber between the dissected surface of the nidus and the brain. They prevent adhesions from forming around the dissected nidus, and facilitate dissection at the time of the second operation. Protection of the Brain During Drilling Covering the brain surface with Silastic sheets protects the cerebral cortex from damage that can be caused by slippage of the drill tip. The Silastic sheets which we
FIG. 1. Protection of the seventh and eighth cranial nerves by a silicone rubber sheet in a patient with meningioma in the right petrosal area. The edges of the silicone rubber sheet are fastened with hemoclips. The nerves are protected from both mechanical and electrical injuries.
678
use have a very smooth slick surface, and do not become dislodged or wrap around the drill tip if touched by it. Discussion
The initial clinical application of a protective rubber sheet in neurosurgery was in operations for the microsurgical anastomosis of fine cerebral arteries, t In this setting, the rubber sheet facilitated this fine surgical maneuver. We have now used rubber sheets in many other surgical situations, as have other groups. The surgical glove is found in every operating room and can be used at any time_ Although rubber from the softest surgical glove can usually be used, the silicone rubber sheet has been found to be more useful because it is thinner and more flexible, and has a smoother surface. A silicone rubber sheet should be sterilized in advance. Silicone rubber produces the least amount of tissue reaction, and is therefore more suitable for temporary implantation in staging operations to prevent adhesions from forming on dissected surfaces. We have used only silicone rubber sheets for this purpose in recent years. We have used silicone rubber sheets for preserving perforating vessels under an aneurysm especially in those cases of large posterior circulation aneurysms. These aneurysms are located in a deep narrow operating field and it is difficult to create enough space between the aneurysm and perforating vessels. On one occasion we encountered some difficulty when a rubber sheet was inadvertently clipped together with the aneurysm. Removing the sheet from the blades of the clip was a problem even after the clip was loosened. Therefore, we now recommend that rubber sheets applied for such purposes have an anchoring thread. Another useful trick is to make a hole near the tip of the sheet prior to inserting a rubber sheet into a narrow space so that the forceps can easily grasp the sheet. Every neurosurgeon has experienced an inadvertent injury to one of the cranial nerves by a poorly placed suction or coagulating forceps, particularly when a large hard tumor lies under the nerves in a narrow operating field. The suction or forceps can cause severe damage to a cranial nerve, especially when the nerve is dry. Although covering the cranial nerve with a rubber sheet is usually unnecessary for a short surgical procedure or in a wide operating field, the surgeon does not have to be wary about touching the nerve with the suction or bipolar forceps if it is protected by a protective rubber sheet. A surgeon must be aware of nerve and vessel injury which can be caused by a brief or careless touch of the bipolar forceps especially when faced with severe bleeding in a narrow field. The placement of a rubber sheet allows the surgeon to devote his attention to controlling the bleeding. Another important principle is that all bipolar coagulating forceps must be electrically insulated with the exception of their tips. Staged operations are sometimes indicated for large arteriovenous malformations. When the previously dis-
J. Neurosurg. / Volume 74/April, 1991
Protective rubber sheets sected surface between the nidus and surrounding brain is approached at the second operation, firm adhesions between the two surfaces are often encountered and bleeding from this area can be troublesome. In order to avoid such difficulty, we usually cover both sides of the dissected plane with Oxycel and insert a silicone rubber sheet between the opposing surfaces. The inserted silicone rubber can easily be seen on postoperative computerized tomography scans. In this situation, the silicone rubber sheet is not only a good marker for the second operation but it also makes the surgery much easier since the surgeon can concentrate more readily on those areas which have not yet been dissected.
J. Neurosurg. / Volume 74/April, 1991
Reference
1. Ya~rgil MG: Microsurgery Applied to Neurosurgery. Stuttgart: Georg Thieme Verlag, 1969, p 40
Manuscript received July 20, 1990. Accepted in final form October 24, 1990. Address reprint requests to: Masato Shibuya, M.D., Department of Neurosurgery, Nagoya University, 466 Nagoya, Japan.
679
Intraoperative protection of cranial nerves and perforating arteries by silicone rubber sheets Technical note MASATO SttlBUYA, M.D., KENICHIRO SUGITA, M.D., AND SHIGEAKI KOBAYASHI, M.D.
Departments of Neurosurgery, Nagoya University, Nagoya, and Shinshu University, Matsumoto, Japan u- The authors describe a technique whereby, during microneurosurgery, vital structures are covered or wrapped with small pieces of silicone rubber sheeting to protect them from intraoperative injury. In this way, perforating arteries located behind a large aneurysm can be covered to avoid their inclusion within the blades of the clip, and the cranial nerves coursing around or through a tumor can be wrapped to protect them from injury by a suction or forceps. By insulating nerves and arteries, this silicone rubber sheet has the added advantage of protecting them from injury due to electrical current of bipolar forceps. The silicone rubber sheet described here is smoother, thinner, and lighter than a cotton pattie. KE~" W o a o s
microneurosurgery
9 silicone rubber sheet
cranial nerve
operative technique
LTHOUGH many kinds of cotton patties are commonly used in the neurosurgical operating field, rubber sheets are also useful in certain situations. A small piece of rubber sheeting was initially described by Ya~argil ~ for use during the microvascular anastomosis of fine cerebral arteries. We discuss the utility of silicone rubber sheets for the protection of critical structures such as cranial nerves and blood vessels during microneurosurgery.
A
Description and Use of Material Sterilized silicone rubber (Silastic) sheets 0.125 mm thick were used. A silicone rubber sheet is preferred to a plain rubber sheet when it must be left in the brain, even temporarily until a second operation, since it causes little tissue reaction. Sheets of various sizes and shapes should be prepared before surgery and can be modified to the appropriate shape. An anchoring thread is tied to the base of the sheet so that it can be easily withdrawn from the depth of the surgical field. When a silicone rubber sheet is not instantly available, a surgical glove can be cut into a variety of different pieces and washed free of lubricating powder prior to use.
J. Neurosurg. / Volume 74/April, 1991
Several techniques illustrating the application of silicone rubber sheet during surgery are listed below.
Protection of Perforating Arteries In operations to clip a large or giant aneurysm, a silicone rubber sheet is useful to protect any perforating vessels coursing under both sides of the aneurysm prior to clip placement. This is particularly important when the aneurysm is so large that both sides cannot be visualized simultaneously in the field afforded by the operating microscope. The rubber sheet allows the blades to slide over the perforating vessels, even when the position of the blades cannot be visualized completely.
Protection of Cranial Nerves A cranial nerve coursing over a tumor may impede removal of the tumor mass and may be subjected to injury. Our approach in such a case is to cover the cranial nerve with a thin silicone rubber sheet where it crosses the tumor. When the nerve lies in the center of the operating field, the sheet is wrapped around the 677
M. Shibuya, K. Sugita, and S. Kobayashi nerve and both ends are closed with small hemoclips so that the sheet will not slide along the nerve. Closing the rubber sheet protects the nerve from accidental injury by suction or forceps during removal of the deeper portion of the tumor. This method is useful for fragile thin nerves such as the first, fourth, sixth, seventh, and eighth cranial nerves, especially when the tumor is firm and the procedure must be carried out in a narrow operating field (Fig. 1).
Protection oJ"Crilical Structure~" 1,)'ore E/eclrica/ Current When a bleeding point behind an important vessel or cranial nerve in a narrow operating field is coagulated with bipolar forceps, the vessel or nerve should be temporarily covered with a rubber sheet. Leakage of electrical current can cause injury to a critical structure when forceps inadvertently touch the nerve or vessel. Prevention ( f Postoperative Adhesions When staged operations are performed for large arteriovenous malformations, we leave sheets of silicone rubber between the dissected surface of the nidus and the brain. They prevent adhesions from forming around the dissected nidus, and facilitate dissection at the time of the second operation. Protection of the Brain During Drilling Covering the brain surface with Silastic sheets protects the cerebral cortex from damage that can be caused by slippage of the drill tip. The Silastic sheets which we
FIG. 1. Protection of the seventh and eighth cranial nerves by a silicone rubber sheet in a patient with meningioma in the right petrosal area. The edges of the silicone rubber sheet are fastened with hemoclips. The nerves are protected from both mechanical and electrical injuries.
678
use have a very smooth slick surface, and do not become dislodged or wrap around the drill tip if touched by it. Discussion
The initial clinical application of a protective rubber sheet in neurosurgery was in operations for the microsurgical anastomosis of fine cerebral arteries, t In this setting, the rubber sheet facilitated this fine surgical maneuver. We have now used rubber sheets in many other surgical situations, as have other groups. The surgical glove is found in every operating room and can be used at any time_ Although rubber from the softest surgical glove can usually be used, the silicone rubber sheet has been found to be more useful because it is thinner and more flexible, and has a smoother surface. A silicone rubber sheet should be sterilized in advance. Silicone rubber produces the least amount of tissue reaction, and is therefore more suitable for temporary implantation in staging operations to prevent adhesions from forming on dissected surfaces. We have used only silicone rubber sheets for this purpose in recent years. We have used silicone rubber sheets for preserving perforating vessels under an aneurysm especially in those cases of large posterior circulation aneurysms. These aneurysms are located in a deep narrow operating field and it is difficult to create enough space between the aneurysm and perforating vessels. On one occasion we encountered some difficulty when a rubber sheet was inadvertently clipped together with the aneurysm. Removing the sheet from the blades of the clip was a problem even after the clip was loosened. Therefore, we now recommend that rubber sheets applied for such purposes have an anchoring thread. Another useful trick is to make a hole near the tip of the sheet prior to inserting a rubber sheet into a narrow space so that the forceps can easily grasp the sheet. Every neurosurgeon has experienced an inadvertent injury to one of the cranial nerves by a poorly placed suction or coagulating forceps, particularly when a large hard tumor lies under the nerves in a narrow operating field. The suction or forceps can cause severe damage to a cranial nerve, especially when the nerve is dry. Although covering the cranial nerve with a rubber sheet is usually unnecessary for a short surgical procedure or in a wide operating field, the surgeon does not have to be wary about touching the nerve with the suction or bipolar forceps if it is protected by a protective rubber sheet. A surgeon must be aware of nerve and vessel injury which can be caused by a brief or careless touch of the bipolar forceps especially when faced with severe bleeding in a narrow field. The placement of a rubber sheet allows the surgeon to devote his attention to controlling the bleeding. Another important principle is that all bipolar coagulating forceps must be electrically insulated with the exception of their tips. Staged operations are sometimes indicated for large arteriovenous malformations. When the previously dis-
J. Neurosurg. / Volume 74/April, 1991
Protective rubber sheets sected surface between the nidus and surrounding brain is approached at the second operation, firm adhesions between the two surfaces are often encountered and bleeding from this area can be troublesome. In order to avoid such difficulty, we usually cover both sides of the dissected plane with Oxycel and insert a silicone rubber sheet between the opposing surfaces. The inserted silicone rubber can easily be seen on postoperative computerized tomography scans. In this situation, the silicone rubber sheet is not only a good marker for the second operation but it also makes the surgery much easier since the surgeon can concentrate more readily on those areas which have not yet been dissected.
J. Neurosurg. / Volume 74/April, 1991
Reference
1. Ya~rgil MG: Microsurgery Applied to Neurosurgery. Stuttgart: Georg Thieme Verlag, 1969, p 40
Manuscript received July 20, 1990. Accepted in final form October 24, 1990. Address reprint requests to: Masato Shibuya, M.D., Department of Neurosurgery, Nagoya University, 466 Nagoya, Japan.
679
