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Coagulation changes during colloid or crystalloid resuscitation from experimental traumatic brain injury
NEUROLOGICAL SURGERY delivery at the tissue level. In this study we discuss our experience with LICOX in major trauma (ISS⬎16).
Coagulation changes during colloid or crystalloid resuscitation from experimental traumatic brain injury
METHODS: 32 patients with major trauma (ISS⬎16) had Pbt02 monitor placed using twist-drill craniostomy and bolt.Pbto2 monitoring directed therapy i.e. ventilator management, ionotropes, blood transfusion etc. The patient demographics, Pbto2, GCS, ICP, Trauma scores and outcomes were recorded. Correlations were made using the STATISTICA software.
David King MD, Stephen Cohn MD, Kenneth Proctor PhD University of Miami School of Medicine, Miami, FL INTRODUCTION: Intravascular coagulation is a major secondary insult after traumatic brain injury (TBI). Hemostasis may be complicated by coagulation changes secondary to hemodilution, hypothermia, acidosis, and by particular resuscitation fluids. Hextend™ is an FDAapproved hetastarch-electrolyte solution. A thromboelastograph (TEG, Haemoscope, Niles, IL) was used to compare multiple coagulation parameters after initial fluid resuscitation from TBI with lactated Ringers’ (LR) or Hextend. There are no previous studies on this problem.
RESULTS: There were 21 males and 11 females with an average age of 30 years (range 12–86). 60% had multiple injuries. There were 25MVA’s, 4 falls, 2 assaults and 1 gunshot. Eleven patients underwent craniotomy for a SOL. There were 13 contusions/ICH, 13 diffuse brain injury/SAH, 4SDH and 2 concussions. The mean trauma scores were ISS⫽32 (16–59), RTS⫽7.3 (4–12) and APACHE-II⫽11 (3–20). Severe cerebral ischemia (Pbto25 mmHg) was seen in 19%, moderate (5–10 mmHg) in 9% and mild (11–20 mmHg) in a further 19% immediately after monitor placement. Correlations were noted between ISS and Pbto2 on insertion (p⬍.05) and Pbt02 on admission and probablity of survival (p⬍.02). The observed mortality was 18.6% as compared to an expected mortality of 30.7% (p⬍.04).
METHODS: Anesthetized, mechanically-ventilated swine (n⫽15) received a frontotemporal fluid percussion injury, followed by hemorrhage (27⫽⫾3 mL/kg) to a mean arterial blood pressure (MAP)⫽25 mmHg. After 30 min, unlimited LR (n⫽8) or Hextend (n⫽7) was administered to restore MAP⬎70 mm Hg and heart rate 100 beats/min. TEG samples were drawn before and 180 min after TBI. To lessen sample variability, duplicate samples were drawn at a fixed flow rate through 7F catheters, analyzed at exactly two minutes, and results averaged. RESULTS: Hextend resuscitation (46⫾13 mL/kg) reduced clotting time (R) by 40%, but clot strength (MA) was also reduced (both p⬍0.05), resulting in no change in overall coagulation status (CI). The changes were similar but more variable with LR resuscitation (256⫾33 mL/kg), but there were no differences between groups. No bleeding was noted clinically. Post-resuscitation hematocrit ⫽14⫾1% (baseline 25⫾1%). Table.
Before TBI after TBI ⫹ Hextend Before TBI after TBI ⫹ LR
R (sec)
MA (mm)
CI
11.8 ⫾ 1.8 6.2 ⫾ 0.8* 12.0 ⫾ 3.2 9.3 ⫾ 1.8
70.5 ⫾ 1.6 60.9 ⫾ 1.5* 71.6 ⫾ 2.9 66.1 ⫾ 2.2
2.7 ⫾ 0.5 2.4 ⫾ 0.3 2.8 ⫾ 1.1 2.4 ⫾ 0.5
CONCLUSIONS: A significant proportion of patients with trauma can have mild to severe cerebral ischemia on admission to hospital correlating with injury severity. LICOX Pbto2 monitoring aids continuous real time monitoring for cerebral ischemia and allows appropriate intervention to minimize the deleterious effects of ischemia and secondary injury.
Neurobiological aspects of cancer anorexia in tumor bearing rats Irina Makarenko PhD, Irina Romanova PhD, Eduardo JB Ramos MD, Susumu Suzuki MD, PhD, Chung Chen PhD, Michael Ugrumov MD, PhD, Tomoi Sato MD, PhD, Michael M Meguid MD, PhD SUNY Upstate Medical University, Surgical Metabolism Laboratory, Syracuse, NY
*p ⬍ 0.05 within group.
CONCLUSIONS: For the first three hours after TBI, with near 50% hemodilution, resuscitation with Hextend produced minimal laboratory abnormalities, and no clinically significant coagulopathy.
INTRODUCTION: Food intake balance in anorexia is under dual hypothalamic NPY (neuropeptide-Y) stimulatory and alpha-MSH (alpha-melanocyte stimulating hormone) and 5-HT (serotonin) inhibitory process. Dietary fish oil (primarily w-3 fatty acid; w-3FA) delays tumor growth, onset of anorexia and reverses the feeding pattern in tumor-bearing rats. We hypothesize that cancer anorexia is associated with hypothalamic down-regulation of NPY and upregulation of alpha-MSH and serotonin which w-3FA modifies hypothalamic activity of these food intake regulators, do to delay tumor growth and onset of anorexia.
LICOX brain oxygen (Pbto2) monitoring in major trauma: study of correlation between trauma scores, brain oxygenation and survival Sathyaprasad C Burjonrappa MD, FRCS, Pradeep Narotam MD, FACS, Ray Gaines MD, Charles Taylon MD, Malini Rao MB, BS, Nalini Narotam MSC, Diane Yetter MSN Creighton University Medical Center, Omaha, NE
METHODS: Fischer rats (220–240 g) were acclimated and divided into 4 groups: MCA tumor bearing on chow (TB-Chow) or on w-3 diet (TB-w-3FA) and controls, non-tumor bearing on chow (NTBChow) or w-3 diet (NTB-w-3FA). Rats were euthanized at onset of anorexia and their brains removed for hypothalamic immunohistochemical study. Free-floating sections and specific antibodies to NPY,
INTRODUCTION: While ICP monitoring reflects the physical changes in the cranium, patients with major trauma may develop cerebral hypoxia and ischemia.Current management of severe head injury which is guided by monitoring ICP, CPP, MAP, SaO2, brain temperature and cerebral blood flow may not indicate true oxygen
© 2003 by the American College of Surgeons Published by Elsevier Inc.
ISSN 1072-7515/03/$21.00
S42
Vol. 197, No. 3S, September 2003
alpha-MSH and 5-HT-1B-receptors were used. Slides were assessed by semiquantitative image analysis and analyzed by t-test. RESULTS: In TB-Chow vs. NTB-Chow, NPY immunoreactivity decreased by 76% in supraoptic nuclei (SON), 50% in paraventricular (PVN) and 30% in arcuate nuclei (ARC). 5-HT1B-receptors increased 40% in SON and 50% in PVN while in SON, PVN and ARC alpha-MSH increased by 26%. In TB-w-3FA rats alpha-MSH increased by 15%, 5-HT1B-receptors by 22% and NPY decreased by 35% (p⬍0.05). CONCLUSIONS: Cancer anorexia is modulated via hypothalamic NPY down-regulation and the combined alpha-MSH and serotonin up-regulation in tumor bearing rats. W-3FA modifies their hypothalamic activity to reverse food intake, delaying tumor growth and onset of anorexia.
The balance between hypothalamic orexigenic and anorexigenic modulators after gastric bypass Irina Romanova PhD, Eduardo JB Ramos MD, Yuan Xu MD, Frank Middleton PhD, Chung Chen PhD, Michael Ugrumov MD, PhD, Akio Inui MD, PhD, Michael M Meguid MD, PhD, FACS SUNY Upstate Medical University, Surgical Metabolism Laboratory, Syracuse, NY INTRODUCTION: Hypothalamus is the major site of food intake and energy regulation, and arcuate (ARC) and paraventricular nuclei (PVN) play key role in this process. Food intake is regulated by the balance between orexigenic and anorexigenic modulators, among them, neuropeptide Y (NPY) increases and alpha-melanocyte stimulating hormone (alpha-MSH) and serotonin (5-HT) decrease appetite. Since morbid obesity is treated most successfully by gastric bypass (GB), we hypothesize that weight loss after GB is modulated via hypothalamic these hypothalamic factors. METHODS: 3–4 weeks old Sprague Dawley (SD) pups were made obese by feeding high-energy diet (HED) for 7 weeks. Obese rats had a GB or sham operation (Control). Both groups continued on HED for 10 days, were euthanized and brains were analyzed. Standard procedures of free-floating sections and specific antibodies to NPY, MSH and 5-HT1B-receptors were used for immunohistochemical analysis. Slides were assessed by semi quantitative image analysis. Data analyzed using t-test. RESULTS: After GB a 17% weight loss occurred (p⬍0.05). Optical density in GB vs. Control in ARC indicates: 30% decrease in NPY, 20% increase of alpha-MSH and 62% increase of 5-HT-1B. In both magnocellular and parvocellular regions of PVN a decreased of 44% and 24% in NPY occurred, while alpha-MSH increased by 15% and 25% and 5-HT-1B-receptor increased by 32% and 70%, respectively (p⬍0.05). CONCLUSIONS: GB induced weight loss is modulated by hypothalamic peptides/ monoamine via NPY down-regulation and alphaMSH and serotonin up-regulation in diet induced obese rats.
Neurological Surgery
S43
Selective peripheral denervation for the treatment of intractable spasmodic torticollis: the mayo clinic experience with 168 patients Aaron A Cohen-Gadol MD, Dudley Davis MD, Eric Ahlskog MD, Joseph Matsumoto MD Mayo Clinic, Rochester, MN INTRODUCTION: We assessed preoperative factors to determine which, if any, correlated with outcomes in patients with torticollis who underwent the selective peripheral denervation procedure. METHODS: The records of 168 consecutive patients who underwent selective peripheral denervation for cervical dystonia between 19881996 at the Mayo Clinic (Rochester, MN) were reviewed. There were 89 (53%) women and 79 (47%) men with the mean age of 53.4 years. Selection of muscles for denervation was based on the clinical presentation and electromyographic mapping studies. The most common torticollis vectors were rotational in 141 (84%) patients and laterocollis in 59 (35%). Seventy patients (42%) presented with combined vectors. RESULTS: At the three-month postoperative evaluation, 125 of 162 available patients (77%) had moderate to excellent improvement in head position; pain was moderately to markedly improved in 131 (81%). Follow-up averaged 3.4 years and was available for 130 patients. The original level of moderate to excellent improvement was retained in at least 71 (70%) patients for head position and pain. Outcome was not predicted by preoperative head position, severity, symptom duration, presence of tremor or phasic dystonic movements, or failure to respond to botulinum toxin treatment. Five patients recovered from postoperative complications including one myocardial infarction, one pulmonary embolism, and three respiratory failures. One patient had a wound infection, and one expired from respiratory arrest. CONCLUSIONS: Selective peripheral denervation is an effective method of achieving lasting improvement of dystonia in most patients with intractable torticollis.
The use of intraoperative magnaetic resonance imaging (iMRI) for resection of pituitary tumors Duane Densler MD, Charles Levy MD, Todd Vitaz MD University of Louisville School of Medicine, Louisville, KY INTRODUCTION: Intraoperative MRI (iMRI) has added a valuable tool to the neurosurgeon’s armamentarium. It allows real-time MR imaging during neurosurgical procedures allowing both trajectory planning and evaluation of surgical results. The use of this new technology has been extremely useful for the resection of pituitary tumors where intraoperative visual feedback may often be limited. METHODS: We prospectively reviewed our series of pituitary tumors treated in the iMRI since July 2002. All patients underwent prooperative neuroimaging and endocrine testing. All surgical procedures were performed in the iMRI suite without use of flouroscopy via the standard transnasal transpenoidal approach. Extent of lesion resection was assessed from images obtained throughout the procedure. RESULTS: All patients were deemed to have a complete resection based on the images acquired at the time of the procedure except for
S44
Neurological Surgery
one patient who had disease that extended into the cavernous sinus (visible on both preoperative and intraoperative images). Postoperatively, patients were followed and evaluated for resolution of endocrine function and or preoperative neurologic deficit; the visual apparatus was decompressed in all patients. There were no intraoperative complications and only one postoperative complication (CSF leak).
J Am Coll Surg
CONCLUSIONS: The use of real-time neuroimaging during operative procedures has improved patients outcomes by allowing more aggressive and complete resections near critical structures. In our experince it has been of value in allowing a more complete resections of pituitary macroadenomas. As these techniques are refined we expect that we will find more innovative uses for this powerful tool.
Coagulation changes during colloid or crystalloid resuscitation from experimental traumatic brain injury
METHODS: 32 patients with major trauma (ISS⬎16) had Pbt02 monitor placed using twist-drill craniostomy and bolt.Pbto2 monitoring directed therapy i.e. ventilator management, ionotropes, blood transfusion etc. The patient demographics, Pbto2, GCS, ICP, Trauma scores and outcomes were recorded. Correlations were made using the STATISTICA software.
David King MD, Stephen Cohn MD, Kenneth Proctor PhD University of Miami School of Medicine, Miami, FL INTRODUCTION: Intravascular coagulation is a major secondary insult after traumatic brain injury (TBI). Hemostasis may be complicated by coagulation changes secondary to hemodilution, hypothermia, acidosis, and by particular resuscitation fluids. Hextend™ is an FDAapproved hetastarch-electrolyte solution. A thromboelastograph (TEG, Haemoscope, Niles, IL) was used to compare multiple coagulation parameters after initial fluid resuscitation from TBI with lactated Ringers’ (LR) or Hextend. There are no previous studies on this problem.
RESULTS: There were 21 males and 11 females with an average age of 30 years (range 12–86). 60% had multiple injuries. There were 25MVA’s, 4 falls, 2 assaults and 1 gunshot. Eleven patients underwent craniotomy for a SOL. There were 13 contusions/ICH, 13 diffuse brain injury/SAH, 4SDH and 2 concussions. The mean trauma scores were ISS⫽32 (16–59), RTS⫽7.3 (4–12) and APACHE-II⫽11 (3–20). Severe cerebral ischemia (Pbto25 mmHg) was seen in 19%, moderate (5–10 mmHg) in 9% and mild (11–20 mmHg) in a further 19% immediately after monitor placement. Correlations were noted between ISS and Pbto2 on insertion (p⬍.05) and Pbt02 on admission and probablity of survival (p⬍.02). The observed mortality was 18.6% as compared to an expected mortality of 30.7% (p⬍.04).
METHODS: Anesthetized, mechanically-ventilated swine (n⫽15) received a frontotemporal fluid percussion injury, followed by hemorrhage (27⫽⫾3 mL/kg) to a mean arterial blood pressure (MAP)⫽25 mmHg. After 30 min, unlimited LR (n⫽8) or Hextend (n⫽7) was administered to restore MAP⬎70 mm Hg and heart rate 100 beats/min. TEG samples were drawn before and 180 min after TBI. To lessen sample variability, duplicate samples were drawn at a fixed flow rate through 7F catheters, analyzed at exactly two minutes, and results averaged. RESULTS: Hextend resuscitation (46⫾13 mL/kg) reduced clotting time (R) by 40%, but clot strength (MA) was also reduced (both p⬍0.05), resulting in no change in overall coagulation status (CI). The changes were similar but more variable with LR resuscitation (256⫾33 mL/kg), but there were no differences between groups. No bleeding was noted clinically. Post-resuscitation hematocrit ⫽14⫾1% (baseline 25⫾1%). Table.
Before TBI after TBI ⫹ Hextend Before TBI after TBI ⫹ LR
R (sec)
MA (mm)
CI
11.8 ⫾ 1.8 6.2 ⫾ 0.8* 12.0 ⫾ 3.2 9.3 ⫾ 1.8
70.5 ⫾ 1.6 60.9 ⫾ 1.5* 71.6 ⫾ 2.9 66.1 ⫾ 2.2
2.7 ⫾ 0.5 2.4 ⫾ 0.3 2.8 ⫾ 1.1 2.4 ⫾ 0.5
CONCLUSIONS: A significant proportion of patients with trauma can have mild to severe cerebral ischemia on admission to hospital correlating with injury severity. LICOX Pbto2 monitoring aids continuous real time monitoring for cerebral ischemia and allows appropriate intervention to minimize the deleterious effects of ischemia and secondary injury.
Neurobiological aspects of cancer anorexia in tumor bearing rats Irina Makarenko PhD, Irina Romanova PhD, Eduardo JB Ramos MD, Susumu Suzuki MD, PhD, Chung Chen PhD, Michael Ugrumov MD, PhD, Tomoi Sato MD, PhD, Michael M Meguid MD, PhD SUNY Upstate Medical University, Surgical Metabolism Laboratory, Syracuse, NY
*p ⬍ 0.05 within group.
CONCLUSIONS: For the first three hours after TBI, with near 50% hemodilution, resuscitation with Hextend produced minimal laboratory abnormalities, and no clinically significant coagulopathy.
INTRODUCTION: Food intake balance in anorexia is under dual hypothalamic NPY (neuropeptide-Y) stimulatory and alpha-MSH (alpha-melanocyte stimulating hormone) and 5-HT (serotonin) inhibitory process. Dietary fish oil (primarily w-3 fatty acid; w-3FA) delays tumor growth, onset of anorexia and reverses the feeding pattern in tumor-bearing rats. We hypothesize that cancer anorexia is associated with hypothalamic down-regulation of NPY and upregulation of alpha-MSH and serotonin which w-3FA modifies hypothalamic activity of these food intake regulators, do to delay tumor growth and onset of anorexia.
LICOX brain oxygen (Pbto2) monitoring in major trauma: study of correlation between trauma scores, brain oxygenation and survival Sathyaprasad C Burjonrappa MD, FRCS, Pradeep Narotam MD, FACS, Ray Gaines MD, Charles Taylon MD, Malini Rao MB, BS, Nalini Narotam MSC, Diane Yetter MSN Creighton University Medical Center, Omaha, NE
METHODS: Fischer rats (220–240 g) were acclimated and divided into 4 groups: MCA tumor bearing on chow (TB-Chow) or on w-3 diet (TB-w-3FA) and controls, non-tumor bearing on chow (NTBChow) or w-3 diet (NTB-w-3FA). Rats were euthanized at onset of anorexia and their brains removed for hypothalamic immunohistochemical study. Free-floating sections and specific antibodies to NPY,
INTRODUCTION: While ICP monitoring reflects the physical changes in the cranium, patients with major trauma may develop cerebral hypoxia and ischemia.Current management of severe head injury which is guided by monitoring ICP, CPP, MAP, SaO2, brain temperature and cerebral blood flow may not indicate true oxygen
© 2003 by the American College of Surgeons Published by Elsevier Inc.
ISSN 1072-7515/03/$21.00
S42
Vol. 197, No. 3S, September 2003
alpha-MSH and 5-HT-1B-receptors were used. Slides were assessed by semiquantitative image analysis and analyzed by t-test. RESULTS: In TB-Chow vs. NTB-Chow, NPY immunoreactivity decreased by 76% in supraoptic nuclei (SON), 50% in paraventricular (PVN) and 30% in arcuate nuclei (ARC). 5-HT1B-receptors increased 40% in SON and 50% in PVN while in SON, PVN and ARC alpha-MSH increased by 26%. In TB-w-3FA rats alpha-MSH increased by 15%, 5-HT1B-receptors by 22% and NPY decreased by 35% (p⬍0.05). CONCLUSIONS: Cancer anorexia is modulated via hypothalamic NPY down-regulation and the combined alpha-MSH and serotonin up-regulation in tumor bearing rats. W-3FA modifies their hypothalamic activity to reverse food intake, delaying tumor growth and onset of anorexia.
The balance between hypothalamic orexigenic and anorexigenic modulators after gastric bypass Irina Romanova PhD, Eduardo JB Ramos MD, Yuan Xu MD, Frank Middleton PhD, Chung Chen PhD, Michael Ugrumov MD, PhD, Akio Inui MD, PhD, Michael M Meguid MD, PhD, FACS SUNY Upstate Medical University, Surgical Metabolism Laboratory, Syracuse, NY INTRODUCTION: Hypothalamus is the major site of food intake and energy regulation, and arcuate (ARC) and paraventricular nuclei (PVN) play key role in this process. Food intake is regulated by the balance between orexigenic and anorexigenic modulators, among them, neuropeptide Y (NPY) increases and alpha-melanocyte stimulating hormone (alpha-MSH) and serotonin (5-HT) decrease appetite. Since morbid obesity is treated most successfully by gastric bypass (GB), we hypothesize that weight loss after GB is modulated via hypothalamic these hypothalamic factors. METHODS: 3–4 weeks old Sprague Dawley (SD) pups were made obese by feeding high-energy diet (HED) for 7 weeks. Obese rats had a GB or sham operation (Control). Both groups continued on HED for 10 days, were euthanized and brains were analyzed. Standard procedures of free-floating sections and specific antibodies to NPY, MSH and 5-HT1B-receptors were used for immunohistochemical analysis. Slides were assessed by semi quantitative image analysis. Data analyzed using t-test. RESULTS: After GB a 17% weight loss occurred (p⬍0.05). Optical density in GB vs. Control in ARC indicates: 30% decrease in NPY, 20% increase of alpha-MSH and 62% increase of 5-HT-1B. In both magnocellular and parvocellular regions of PVN a decreased of 44% and 24% in NPY occurred, while alpha-MSH increased by 15% and 25% and 5-HT-1B-receptor increased by 32% and 70%, respectively (p⬍0.05). CONCLUSIONS: GB induced weight loss is modulated by hypothalamic peptides/ monoamine via NPY down-regulation and alphaMSH and serotonin up-regulation in diet induced obese rats.
Neurological Surgery
S43
Selective peripheral denervation for the treatment of intractable spasmodic torticollis: the mayo clinic experience with 168 patients Aaron A Cohen-Gadol MD, Dudley Davis MD, Eric Ahlskog MD, Joseph Matsumoto MD Mayo Clinic, Rochester, MN INTRODUCTION: We assessed preoperative factors to determine which, if any, correlated with outcomes in patients with torticollis who underwent the selective peripheral denervation procedure. METHODS: The records of 168 consecutive patients who underwent selective peripheral denervation for cervical dystonia between 19881996 at the Mayo Clinic (Rochester, MN) were reviewed. There were 89 (53%) women and 79 (47%) men with the mean age of 53.4 years. Selection of muscles for denervation was based on the clinical presentation and electromyographic mapping studies. The most common torticollis vectors were rotational in 141 (84%) patients and laterocollis in 59 (35%). Seventy patients (42%) presented with combined vectors. RESULTS: At the three-month postoperative evaluation, 125 of 162 available patients (77%) had moderate to excellent improvement in head position; pain was moderately to markedly improved in 131 (81%). Follow-up averaged 3.4 years and was available for 130 patients. The original level of moderate to excellent improvement was retained in at least 71 (70%) patients for head position and pain. Outcome was not predicted by preoperative head position, severity, symptom duration, presence of tremor or phasic dystonic movements, or failure to respond to botulinum toxin treatment. Five patients recovered from postoperative complications including one myocardial infarction, one pulmonary embolism, and three respiratory failures. One patient had a wound infection, and one expired from respiratory arrest. CONCLUSIONS: Selective peripheral denervation is an effective method of achieving lasting improvement of dystonia in most patients with intractable torticollis.
The use of intraoperative magnaetic resonance imaging (iMRI) for resection of pituitary tumors Duane Densler MD, Charles Levy MD, Todd Vitaz MD University of Louisville School of Medicine, Louisville, KY INTRODUCTION: Intraoperative MRI (iMRI) has added a valuable tool to the neurosurgeon’s armamentarium. It allows real-time MR imaging during neurosurgical procedures allowing both trajectory planning and evaluation of surgical results. The use of this new technology has been extremely useful for the resection of pituitary tumors where intraoperative visual feedback may often be limited. METHODS: We prospectively reviewed our series of pituitary tumors treated in the iMRI since July 2002. All patients underwent prooperative neuroimaging and endocrine testing. All surgical procedures were performed in the iMRI suite without use of flouroscopy via the standard transnasal transpenoidal approach. Extent of lesion resection was assessed from images obtained throughout the procedure. RESULTS: All patients were deemed to have a complete resection based on the images acquired at the time of the procedure except for
S44
Neurological Surgery
one patient who had disease that extended into the cavernous sinus (visible on both preoperative and intraoperative images). Postoperatively, patients were followed and evaluated for resolution of endocrine function and or preoperative neurologic deficit; the visual apparatus was decompressed in all patients. There were no intraoperative complications and only one postoperative complication (CSF leak).
J Am Coll Surg
CONCLUSIONS: The use of real-time neuroimaging during operative procedures has improved patients outcomes by allowing more aggressive and complete resections near critical structures. In our experince it has been of value in allowing a more complete resections of pituitary macroadenomas. As these techniques are refined we expect that we will find more innovative uses for this powerful tool.