J Neurosurg 72:975-979, 1990
Hyperthermia catheter implantation and therapy in the brain Technical note J. ALEXANDER MARCHOSKY, M.D., CHRISTOPHER J. MORAN, M.D., SEAL E. FEARNOT, PH.D, E.E., AND CHARLES F. BABBS, M . D . , PH.D. Neurosurgical Associates, Chesterfield, and Missouri Baptist Medical Center, St. Louis, Missouri; and M E D Instilute and Purdue University, West Lafayette, Indiana ~" For the treatment of malignant gliomas, a technique for implanting hyperthermia catheters was developed that utilized a stereotactic template and head-stabilization frame mounted on a computerized tomography (CT) scanner. Computerized tomography scans were used to measure tumor dimensions and to determine the number, implantation depths, and active heating lengths of the catheters, which were implanted through twistdrill holes while the patient was in the CT room. Heat was subsequently delivered via implanted catheters using a computer-controlled hyperthermia system, which partially compensates for heterogeneous and timevarying tumor blood flow. KEY WORDS hyperthermia
9
brain neoplasm 9 anaplastic a s t r o c y t o m a 9 interstitial implantation - s t e r e o t a x y
M
ALIGNANT brain t u m o r s are devastating, and presently there is no widely successful treatment. Laboratory and clinical studies suggest improved effectiveness with a combination of radiation therapy, chemotherapy, and hyperthermia. 2,4,7'8 While working toward an interstitially delivered combination of irradiation, chemotherapy, and hyperthermia, the authors developed an unconventional method of catheter-delivered hyperthermia. Since interstitial irradiation and chemotherapy are typically administered over a series o f days, the protocol and equipment for hyperthermia were likewise devised to allow treatment over a multi-day period. Furthermore, to avoid adverse effects of the heterogeneous and time-varying blood perfusion which plagues conventional hyperthermia devices, the temperature o f each catheter is independently adjusted under c o m p u t e r control to compensate for varying thermal characteristics o f tissue around the catheter.l'3 This technical note describes the stereotactic technique for implanting catheters using computerized tomography (CT) guidance, and the protocol for hyperthermia therapy. J. Neurosurg. / Volume 72/June, 1990
9 glioblastoma multiforme
9
M a t e r i a l s and M e t h o d s
Stereotactic A p p a r a t u s A head-stabilization frame* was developed for CTguided needle biopsy 5'6 and volumetric implantation of multiple catheters in the brain. The frame is attached firmly to the end of the C T scan table (Fig. 1) and consists o f four m a j o r components: a support base attached to the C T table, a ring-shaped frame, an auxiliary head support attached to the ring-shaped frame, and a template to guide catheter placement. Adjustable nylon pads, three placed under the head a n d two placed superiorly on the ring, stabilize the head within the ring and eliminate the need for skull perforation to secure the head position. The auxiliary head support has six additional adjustable support pads to provide further support against downward force and torque during drilling. A template, made of a polycarbonate block 2 c m thick with 2.5-ram apertures in staggered rows (Fig. * Head frame manufactured by Cook, Inc., Bloomington, Indiana. 975
J. A. Marchosky, et al.
FIG. 1. Computerized tomography (CT)-mounted stereotactic frame for catheter implantation. A sterilized plastic template is supported by the ring-shaped frame attached to the CT scan table. The carriage on the ring allows five ways of adjusting the template position. The patient's head is supported by pads on the auxiliary head support.
2), is used to guide the drill, biopsy needle, and catheters and to maintain the desired intercatheter spacing during implantation.
Catheters The hyperthermia catheters are 2.2 m m in diameter and can emit heat along a specified section of the implanted segment of the catheter (Fig. 3) which is 2, 3, 4, 5, 6, 7, or 8 cm long. Heat is generated within the catheters by electrically resistive heating elements, warmed by passage of direct current under computer
FIG. 3. The implantable ends of the heat-emitting (upper) and independent thermometry (lower) catheters. The heatemitting catheter has a conical tip to facilitate insertion and a 3-cm electrically resistive heating element to warm the tumor segment by thermal conduction. A thermistor to monitor catheter temperature is located midway in the heating section. In the independent thermometry catheter, thermistors are located 1 cm apart.
control. Heat is transferred to the tissue via thermal conduction. Electrical connectors for attachment to hyperthermia generator cables are located on the nonimplanted end. In addition to the heating element, each heating catheter contains a thermistor for measurement of catheter temperature. Smaller independent thermometry catheters, 1.2 m m in diameter, were implanted in selected patients to monitor tissue temperatures between heat-emitting catheters. The independent thermometry catheters have
FIG. 2. Templates for guiding catheter implantation. Staggered rows of apertures, forming repeated equilateral triangles, permit 15-mm spacing of hyperthermia catheters. The smaller apertures allow placement of independent thermometry catheters. A white strip along the edge of the template is used to register the computerized tomography (CT) scanner at zero using the CT alignment laser. To facilitate implantations on a curvature of the skull, a wedge was added to the template. 976
J. Neurosurg. / Volume 72~June, 1990
Hyperthermia catheter implantation in brain
FIG. 4. Computerized tomography (CT) image measurement for implantation planning. The distance from the template surface to the far side of the tumor (l) and distance across the tumor (2) were measured on the CT scan. Measurements were repeated for each aperture of the template intersecting the tumor on serial CT images spaced at 7.5 mm.
either one thermistor or four separate temperaturesensing points spaced 1 cm apart along the implanted segment (Fig. 3).
CT-Guided Implantation Technique The hyperthermia and t h e r m o m e t r y catheters were implanted percutaneously, utilizing interactive CT scanning and surgery. The entire procedure was performed in the CT suite. The CT-based approach was time-saving because it allowed t u m o r location, treatm e n t planning, and surgical implantation and place-
FIG. 5. Drilling of skull holes and catheter placement using the template. The 2.5-mm holes were drilled in the desired apertures, and catheters with the required heating element length were implanted through the template to the measured depth.
J. Neurosurg. / Volume 72/June, 1990
m e n t confirmation of up to 16 catheters in approximately 2 hours while the patient was in the C T r o o m without the need for transportation to the operating room. After induction o f general anesthesia by inhalation, the patient was positioned on the C T table with the t u m o r uppermost, and the head was secured in the stereotactic stabilization frame (Fig. 1). Before catheter implantation, the scalp was shaved, treated with antibacterial solution, and draped so that the sterile field encompassed the superior surface of the head. A ~ - i n . sheet o f sterile silicone was stapled to the skull over the area to receive catheters and the stereotactic template was positioned over the silicone sheet. The CT scanner was used for treatment planning, which involved determining three-dimensional placem e n t of the catheters in appropriate positions to heat the t u m o r volume. Contrast-enhanced CT brain scans were p e r f o r m e d 7.5 m m apart in planes passing through sequential rows of apertures in the template so that a section through the t u m o r and the corresponding template apertures was visible on each C T image (Fig. 4). Each axial image showing the skull, the t u m o r enhancement, and the intersecting row of template apertures was displayed and a line was projected through each aperture intersecting the t u m o r volume. Each aperture with a projection intersecting the t u m o r was chosen as a site for catheter implantation. The desired depth o f implantation and the required length of the heating portion o f each catheter were then determined using CT scanner software. The CT-measured distance f r o m the surface o f the template to the far side of the enh a n c e m e n t region provided the desired depth of implantation. A second distance across the t u m o r was used to determine the length of heated catheter, ranging from 2 to 8 cm. In the same manner, locations for the independent t h e r m o m e t r y catheters, if used, were chosen and the depth o f implantation planned. To i m p l a n t the catheters, the silicone sheet, skull, and dura were perforated in the planned locations using a sterile, battery-powered twist drill and 2 . 5 - m m bit (Fig. 5). T h e semi-rigid catheters were inserted in staggered rows through the template and skull holes to predetermined depths, maintaining parallelism with a 15-mm distance between catheters. Repeat C T scans were taken to verify the location and correct p l a c e m e n t of the catheters (quality assurance) (Fig. 6). Required adjustments, if any, were made immediately and confirmed by rescanning. The template was removed, and a drop o f cyanoacrylate ester cement was placed on the junction o f each catheter and the silicone sheet. For a cranial dressing, a ring o f layered f o a m t was placed around the implantation site and the center was filled with silicone elastomer$ as added protection against t Reston Adaptable Foam manufactured by 3M Co., St. Paul, Minnesota. Silicone elastomer manufactured by Smith & Nephew Rolyan, Menomonee Falls, Wisconsin. 977
J. A. Marchosky, et al.
FIG. 6. Postimplantation computerized tomography scans taken to confirm hemostasis and catheter placement. If needed, adjustments in depth or placement were made and confirmed by rescanning.
cription specifying the treatment temperature, duration, and fractionation was entered into the hyperthermia computer. Typically, 72 hours of hyperthermia were delivered over 96 hours, elevating temperature during 3 o f every 4 hours, allowing a 1-hour disconnection between treatments. Temperatures o f each catheter were monitored through the thermistors approximately every 3 seconds; temperatures (resolution 0.1 ~ were displayed on the cathrode ray tube screen and recorded by the computer. Patient monitoring included vital signs, core body temperature, serum electrolytes, and neurological status. The technique included appropriate regimens o f steroids, anticonvulsants, antibiotics, Dextran 40 (600 ml/day) for prophylaxis against venous thrombus formation, 9'1~and lidocaine (100 to 120 mg/ hr) administered to potentiate hyperthermia effects by acting on the t u m o r cell membrane.ll The catheters were explanted 4 days after placement, when the treatment was completed. Since the catheters were cemented to the stapled silicone sheet, the staples were removed first, then all catheters were removed simultaneously with the sheet. A pressure bandage was placed over the area, but suturing the explant sites was not necessary. Contrast-enhanced CT scans were taken to assess t u m o r status, mass effect, and hemostasis. Discharge from the hospital, as indicated by the patient's clinical condition, was followed by subsequent treatments scheduled at 4- to 6-week intervals if indicated. Follow-up monitoring included evaluation by neurological examination and CT scans every 6 to 8 weeks. Steroids were continued until CT scans demonstrated reduction of edema and mass effect; dosages were tapered thereafter. Anticonvulsant regimens were maintained throughout the follow-up period. Discussion
FIG. 7. Cranial dressing of layered foam and silicone elastomer used to secure the catheters.
accidental displacement (Fig. 7). After implantation of the hyperthermia catheters, patients were transferred to the neurosurgical intensive care unit for postanesthesia recovery and hyperthermia treatment.
Hyperthermia Treatment Technique In the neurosurgical intensive care unit, the connector ends of the catheters were inserted into manifolds for connection to the hyperthermia system.w Before initiating the hyperthermia treatment, a preswHyperthermia system VH8500 manufactured by Cook Inc., Bloomington, Indiana. 978
The development of the present technique followed several years' experience with interstitial brachytherapy, during which the ability to implant multiple small catheters into the brain was demonstrated. The use of small twist-drill holes instead of the conventional burr hole reduced surgical time. The small skull holes required no suturing after the catheters were removed and were barely visible 1 month after catheter explantation. The use of the CT scanner to guide t u m o r biopsy, treatment planning, and verification of the correct catheter placement proved expeditious. The CT-based stereotactic system simplified the implantation procedure and contributed to patient safety in three ways. First, placement of several catheters was more time-efficient than using conventional, separate CT and operating room arrangements. The CT-based approach obviated the need for double staffing, transporting the patient, and cranial positioning screws. Second, immediate confirmation o f the integrity and placement of the catheters and the absence of intraprocedural complications was
J. Neurosurg. / Volume 72/June, 1990
Hyperthermia catheter implantation in brain possible. F i n a l l y , skin p e r f o r a t i o n was n o t r e q u i r e d for head stabilization. A possible d i s a d v a n t a g e o f this technique, however, is t h e c o n t i n u o u s use o f the C T r o o m for a p p r o x i m a t e l y 2 hours. This t e c h n i q u e is being e v a l u a t e d in further clinical studies.
Acknowledgments The authors thank Deborah Welsh, R.N., and Connie Zumwalt, R.N., for their assistance with the development of this technique.
References 1. Babbs, CF, Fearnot NE, Marchosky JA, et al: Properties of interstitial conductive heat therapy for cancer, demonstrated in computer simulation. IEEE Trans Biomed Eng (In press, 1990) 2. Coughlin CT, Douple EB, Strohbehn JW, et al: Interstitial hyperthermia in combination with brachytherapy. Radiology 148:285-288, 1983 3. Deford JA, Babbs CF, Patel UH, et at: Accuracy and precision of computer simulated tissue temperatures in individual human intracranial tumors treated with interstitial hyperthermia. Int J Hyperthermia 6: (In press, 1990) 4. Hahn GM, Braun J, Har-Kedar I: Thermochemotherapy: synergism between hyperthermia (42-43*) and Adriamycin (or Bleomycin) in mammalian cell inactivation. Proc
Y. Neurosurg. / Volume 72/June, 1990
Natl Acad Sci USA 72:937-940, 1975 5. Marchosky JA, Moran CJ: A simple stereotaxic CTcontrolled brain biopsy system for general neurosurgical use. Contemp Neurosurg 5:1-8, 1983 6. Moran C, Naidich TP, Marchoski JA: CT-guided needle placement in the central nervous system: results in 146 consecutive patients. A J R 143:861-868, 1984 7. Overgaard J: Fractionated radiation and hypertherrnia: experimental and clinical studies. Cancer 48:1116-1123, 1981 8. Perez CA, Nussbaum G, Emani B, et al: Clinical results of irradiation combined with local hyperthermia. Cancer 52:1597-1603, 1983 9. Powers SK, Edwards MSB: Prophylaxis of thromboembolism in the neurosurgical patient: a review. Neurosnrgery 10:509-513, 1982 10. Ruff RL, Posner JB: Incidence and treatment of peripheral venous thrombosis in patients with glioma. Ann Neurol 13:334-336, 1983 11. Yatvin MB: The influence of membrane lipid composition and procaine on hyperthermic death of cells. Int J Radiat Biol 32:513-521, 1977 Manuscript received March 27, 1989. Accepted in final form December 1, 1989. This work was supported in part by Grant CA38144 from the National Cancer Institute. Address reprint requests to: J. Alexander Marchosky, M.D., Neurosurgical Associates, 224 South Woods Mill Road, Chesterfield, Missouri 63017.
979
Hyperthermia catheter implantation and therapy in the brain Technical note J. ALEXANDER MARCHOSKY, M.D., CHRISTOPHER J. MORAN, M.D., SEAL E. FEARNOT, PH.D, E.E., AND CHARLES F. BABBS, M . D . , PH.D. Neurosurgical Associates, Chesterfield, and Missouri Baptist Medical Center, St. Louis, Missouri; and M E D Instilute and Purdue University, West Lafayette, Indiana ~" For the treatment of malignant gliomas, a technique for implanting hyperthermia catheters was developed that utilized a stereotactic template and head-stabilization frame mounted on a computerized tomography (CT) scanner. Computerized tomography scans were used to measure tumor dimensions and to determine the number, implantation depths, and active heating lengths of the catheters, which were implanted through twistdrill holes while the patient was in the CT room. Heat was subsequently delivered via implanted catheters using a computer-controlled hyperthermia system, which partially compensates for heterogeneous and timevarying tumor blood flow. KEY WORDS hyperthermia
9
brain neoplasm 9 anaplastic a s t r o c y t o m a 9 interstitial implantation - s t e r e o t a x y
M
ALIGNANT brain t u m o r s are devastating, and presently there is no widely successful treatment. Laboratory and clinical studies suggest improved effectiveness with a combination of radiation therapy, chemotherapy, and hyperthermia. 2,4,7'8 While working toward an interstitially delivered combination of irradiation, chemotherapy, and hyperthermia, the authors developed an unconventional method of catheter-delivered hyperthermia. Since interstitial irradiation and chemotherapy are typically administered over a series o f days, the protocol and equipment for hyperthermia were likewise devised to allow treatment over a multi-day period. Furthermore, to avoid adverse effects of the heterogeneous and time-varying blood perfusion which plagues conventional hyperthermia devices, the temperature o f each catheter is independently adjusted under c o m p u t e r control to compensate for varying thermal characteristics o f tissue around the catheter.l'3 This technical note describes the stereotactic technique for implanting catheters using computerized tomography (CT) guidance, and the protocol for hyperthermia therapy. J. Neurosurg. / Volume 72/June, 1990
9 glioblastoma multiforme
9
M a t e r i a l s and M e t h o d s
Stereotactic A p p a r a t u s A head-stabilization frame* was developed for CTguided needle biopsy 5'6 and volumetric implantation of multiple catheters in the brain. The frame is attached firmly to the end of the C T scan table (Fig. 1) and consists o f four m a j o r components: a support base attached to the C T table, a ring-shaped frame, an auxiliary head support attached to the ring-shaped frame, and a template to guide catheter placement. Adjustable nylon pads, three placed under the head a n d two placed superiorly on the ring, stabilize the head within the ring and eliminate the need for skull perforation to secure the head position. The auxiliary head support has six additional adjustable support pads to provide further support against downward force and torque during drilling. A template, made of a polycarbonate block 2 c m thick with 2.5-ram apertures in staggered rows (Fig. * Head frame manufactured by Cook, Inc., Bloomington, Indiana. 975
J. A. Marchosky, et al.
FIG. 1. Computerized tomography (CT)-mounted stereotactic frame for catheter implantation. A sterilized plastic template is supported by the ring-shaped frame attached to the CT scan table. The carriage on the ring allows five ways of adjusting the template position. The patient's head is supported by pads on the auxiliary head support.
2), is used to guide the drill, biopsy needle, and catheters and to maintain the desired intercatheter spacing during implantation.
Catheters The hyperthermia catheters are 2.2 m m in diameter and can emit heat along a specified section of the implanted segment of the catheter (Fig. 3) which is 2, 3, 4, 5, 6, 7, or 8 cm long. Heat is generated within the catheters by electrically resistive heating elements, warmed by passage of direct current under computer
FIG. 3. The implantable ends of the heat-emitting (upper) and independent thermometry (lower) catheters. The heatemitting catheter has a conical tip to facilitate insertion and a 3-cm electrically resistive heating element to warm the tumor segment by thermal conduction. A thermistor to monitor catheter temperature is located midway in the heating section. In the independent thermometry catheter, thermistors are located 1 cm apart.
control. Heat is transferred to the tissue via thermal conduction. Electrical connectors for attachment to hyperthermia generator cables are located on the nonimplanted end. In addition to the heating element, each heating catheter contains a thermistor for measurement of catheter temperature. Smaller independent thermometry catheters, 1.2 m m in diameter, were implanted in selected patients to monitor tissue temperatures between heat-emitting catheters. The independent thermometry catheters have
FIG. 2. Templates for guiding catheter implantation. Staggered rows of apertures, forming repeated equilateral triangles, permit 15-mm spacing of hyperthermia catheters. The smaller apertures allow placement of independent thermometry catheters. A white strip along the edge of the template is used to register the computerized tomography (CT) scanner at zero using the CT alignment laser. To facilitate implantations on a curvature of the skull, a wedge was added to the template. 976
J. Neurosurg. / Volume 72~June, 1990
Hyperthermia catheter implantation in brain
FIG. 4. Computerized tomography (CT) image measurement for implantation planning. The distance from the template surface to the far side of the tumor (l) and distance across the tumor (2) were measured on the CT scan. Measurements were repeated for each aperture of the template intersecting the tumor on serial CT images spaced at 7.5 mm.
either one thermistor or four separate temperaturesensing points spaced 1 cm apart along the implanted segment (Fig. 3).
CT-Guided Implantation Technique The hyperthermia and t h e r m o m e t r y catheters were implanted percutaneously, utilizing interactive CT scanning and surgery. The entire procedure was performed in the CT suite. The CT-based approach was time-saving because it allowed t u m o r location, treatm e n t planning, and surgical implantation and place-
FIG. 5. Drilling of skull holes and catheter placement using the template. The 2.5-mm holes were drilled in the desired apertures, and catheters with the required heating element length were implanted through the template to the measured depth.
J. Neurosurg. / Volume 72/June, 1990
m e n t confirmation of up to 16 catheters in approximately 2 hours while the patient was in the C T r o o m without the need for transportation to the operating room. After induction o f general anesthesia by inhalation, the patient was positioned on the C T table with the t u m o r uppermost, and the head was secured in the stereotactic stabilization frame (Fig. 1). Before catheter implantation, the scalp was shaved, treated with antibacterial solution, and draped so that the sterile field encompassed the superior surface of the head. A ~ - i n . sheet o f sterile silicone was stapled to the skull over the area to receive catheters and the stereotactic template was positioned over the silicone sheet. The CT scanner was used for treatment planning, which involved determining three-dimensional placem e n t of the catheters in appropriate positions to heat the t u m o r volume. Contrast-enhanced CT brain scans were p e r f o r m e d 7.5 m m apart in planes passing through sequential rows of apertures in the template so that a section through the t u m o r and the corresponding template apertures was visible on each C T image (Fig. 4). Each axial image showing the skull, the t u m o r enhancement, and the intersecting row of template apertures was displayed and a line was projected through each aperture intersecting the t u m o r volume. Each aperture with a projection intersecting the t u m o r was chosen as a site for catheter implantation. The desired depth o f implantation and the required length of the heating portion o f each catheter were then determined using CT scanner software. The CT-measured distance f r o m the surface o f the template to the far side of the enh a n c e m e n t region provided the desired depth of implantation. A second distance across the t u m o r was used to determine the length of heated catheter, ranging from 2 to 8 cm. In the same manner, locations for the independent t h e r m o m e t r y catheters, if used, were chosen and the depth o f implantation planned. To i m p l a n t the catheters, the silicone sheet, skull, and dura were perforated in the planned locations using a sterile, battery-powered twist drill and 2 . 5 - m m bit (Fig. 5). T h e semi-rigid catheters were inserted in staggered rows through the template and skull holes to predetermined depths, maintaining parallelism with a 15-mm distance between catheters. Repeat C T scans were taken to verify the location and correct p l a c e m e n t of the catheters (quality assurance) (Fig. 6). Required adjustments, if any, were made immediately and confirmed by rescanning. The template was removed, and a drop o f cyanoacrylate ester cement was placed on the junction o f each catheter and the silicone sheet. For a cranial dressing, a ring o f layered f o a m t was placed around the implantation site and the center was filled with silicone elastomer$ as added protection against t Reston Adaptable Foam manufactured by 3M Co., St. Paul, Minnesota. Silicone elastomer manufactured by Smith & Nephew Rolyan, Menomonee Falls, Wisconsin. 977
J. A. Marchosky, et al.
FIG. 6. Postimplantation computerized tomography scans taken to confirm hemostasis and catheter placement. If needed, adjustments in depth or placement were made and confirmed by rescanning.
cription specifying the treatment temperature, duration, and fractionation was entered into the hyperthermia computer. Typically, 72 hours of hyperthermia were delivered over 96 hours, elevating temperature during 3 o f every 4 hours, allowing a 1-hour disconnection between treatments. Temperatures o f each catheter were monitored through the thermistors approximately every 3 seconds; temperatures (resolution 0.1 ~ were displayed on the cathrode ray tube screen and recorded by the computer. Patient monitoring included vital signs, core body temperature, serum electrolytes, and neurological status. The technique included appropriate regimens o f steroids, anticonvulsants, antibiotics, Dextran 40 (600 ml/day) for prophylaxis against venous thrombus formation, 9'1~and lidocaine (100 to 120 mg/ hr) administered to potentiate hyperthermia effects by acting on the t u m o r cell membrane.ll The catheters were explanted 4 days after placement, when the treatment was completed. Since the catheters were cemented to the stapled silicone sheet, the staples were removed first, then all catheters were removed simultaneously with the sheet. A pressure bandage was placed over the area, but suturing the explant sites was not necessary. Contrast-enhanced CT scans were taken to assess t u m o r status, mass effect, and hemostasis. Discharge from the hospital, as indicated by the patient's clinical condition, was followed by subsequent treatments scheduled at 4- to 6-week intervals if indicated. Follow-up monitoring included evaluation by neurological examination and CT scans every 6 to 8 weeks. Steroids were continued until CT scans demonstrated reduction of edema and mass effect; dosages were tapered thereafter. Anticonvulsant regimens were maintained throughout the follow-up period. Discussion
FIG. 7. Cranial dressing of layered foam and silicone elastomer used to secure the catheters.
accidental displacement (Fig. 7). After implantation of the hyperthermia catheters, patients were transferred to the neurosurgical intensive care unit for postanesthesia recovery and hyperthermia treatment.
Hyperthermia Treatment Technique In the neurosurgical intensive care unit, the connector ends of the catheters were inserted into manifolds for connection to the hyperthermia system.w Before initiating the hyperthermia treatment, a preswHyperthermia system VH8500 manufactured by Cook Inc., Bloomington, Indiana. 978
The development of the present technique followed several years' experience with interstitial brachytherapy, during which the ability to implant multiple small catheters into the brain was demonstrated. The use of small twist-drill holes instead of the conventional burr hole reduced surgical time. The small skull holes required no suturing after the catheters were removed and were barely visible 1 month after catheter explantation. The use of the CT scanner to guide t u m o r biopsy, treatment planning, and verification of the correct catheter placement proved expeditious. The CT-based stereotactic system simplified the implantation procedure and contributed to patient safety in three ways. First, placement of several catheters was more time-efficient than using conventional, separate CT and operating room arrangements. The CT-based approach obviated the need for double staffing, transporting the patient, and cranial positioning screws. Second, immediate confirmation o f the integrity and placement of the catheters and the absence of intraprocedural complications was
J. Neurosurg. / Volume 72/June, 1990
Hyperthermia catheter implantation in brain possible. F i n a l l y , skin p e r f o r a t i o n was n o t r e q u i r e d for head stabilization. A possible d i s a d v a n t a g e o f this technique, however, is t h e c o n t i n u o u s use o f the C T r o o m for a p p r o x i m a t e l y 2 hours. This t e c h n i q u e is being e v a l u a t e d in further clinical studies.
Acknowledgments The authors thank Deborah Welsh, R.N., and Connie Zumwalt, R.N., for their assistance with the development of this technique.
References 1. Babbs, CF, Fearnot NE, Marchosky JA, et al: Properties of interstitial conductive heat therapy for cancer, demonstrated in computer simulation. IEEE Trans Biomed Eng (In press, 1990) 2. Coughlin CT, Douple EB, Strohbehn JW, et al: Interstitial hyperthermia in combination with brachytherapy. Radiology 148:285-288, 1983 3. Deford JA, Babbs CF, Patel UH, et at: Accuracy and precision of computer simulated tissue temperatures in individual human intracranial tumors treated with interstitial hyperthermia. Int J Hyperthermia 6: (In press, 1990) 4. Hahn GM, Braun J, Har-Kedar I: Thermochemotherapy: synergism between hyperthermia (42-43*) and Adriamycin (or Bleomycin) in mammalian cell inactivation. Proc
Y. Neurosurg. / Volume 72/June, 1990
Natl Acad Sci USA 72:937-940, 1975 5. Marchosky JA, Moran CJ: A simple stereotaxic CTcontrolled brain biopsy system for general neurosurgical use. Contemp Neurosurg 5:1-8, 1983 6. Moran C, Naidich TP, Marchoski JA: CT-guided needle placement in the central nervous system: results in 146 consecutive patients. A J R 143:861-868, 1984 7. Overgaard J: Fractionated radiation and hypertherrnia: experimental and clinical studies. Cancer 48:1116-1123, 1981 8. Perez CA, Nussbaum G, Emani B, et al: Clinical results of irradiation combined with local hyperthermia. Cancer 52:1597-1603, 1983 9. Powers SK, Edwards MSB: Prophylaxis of thromboembolism in the neurosurgical patient: a review. Neurosnrgery 10:509-513, 1982 10. Ruff RL, Posner JB: Incidence and treatment of peripheral venous thrombosis in patients with glioma. Ann Neurol 13:334-336, 1983 11. Yatvin MB: The influence of membrane lipid composition and procaine on hyperthermic death of cells. Int J Radiat Biol 32:513-521, 1977 Manuscript received March 27, 1989. Accepted in final form December 1, 1989. This work was supported in part by Grant CA38144 from the National Cancer Institute. Address reprint requests to: J. Alexander Marchosky, M.D., Neurosurgical Associates, 224 South Woods Mill Road, Chesterfield, Missouri 63017.
979
