Effects of laminectomy on spinal cord blood flow

1978 ◽  
Vol 48 (2) ◽  
pp. 232-238 ◽  
Author(s):  
Douglas K. Anderson ◽  
Gregory R. Nicolosi ◽  
Eugene D. Means ◽  
L. Edward Hartley
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Cord Blood ◽  
Reference Sample ◽  
Significant Decline ◽  
Entire Length ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Sample Method ◽  
Fine Print

✓ The effect of a one-segment (L-2) laminectomy on spinal cord blood flow (SCBF) was determined by the reference sample method using isotope-labeled microspheres. The SCBF was measured before laminectomy (control) and at 15 minutes postlaminectomy with the dura exposed (Series 1), 1 hour postlaminectomy with the laminectomy site closed (Series 2), 24 hours postlaminectomy with the laminectomy site closed (Series 3), and 24 hours postlaminectomy with the dura exposed (Series 4). With the laminectomy site open, SCBF was significantly depressed (22% to 45%) along the entire length of the spinal cord at 15 minutes postlaminectomy. At 1 hour postlaminectomy (with the laminectomy site closed), SCBF approached control values, although areas with significantly lowered flow were still observed in all portions of the spinal cord. By 24 hours postlaminectomy, SCBF had returned to prelaminectomy levels. However, if within 1 hour preceding the 24-hour SCBF measurement, the laminectomy site was reopened, SCBF tended to fall at and caudad to the laminectomy site. These data indicate that laminectomy can cause a significant decline in SCBF. At the present time, the mechanism(s) for this laminectomy-induced depression of SCBF are unknown, although a temperature-induced vasoconstriction is suspected.

Spinal Cord Blood Flow in Experimental Transient Traumatic Paraplegia

1980 ◽  
Vol 52 (3) ◽  
pp. 335-345 ◽  
Author(s):  
Dean C. Lohse ◽  
Howard J. Senter ◽  
John S. Kauer ◽  
Richard Wohns
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
White Matter ◽  
Cord Blood ◽  
Spinal Cord Blood Flow ◽  
Flow Measurements ◽  
Content Type ◽  
The Mean ◽  
Blood Flow Measurements ◽  
Fine Print

✓ Blood flow in the lateral funiculus of the thoracic spinal cord was measured in 24 anesthetized cats using the hydrogen clearance method. In a control series of eight nontraumatized animals, blood flow measurements were taken from the T-5 and T-6 segments for 6 consecutive hours. The mean spinal cord blood flow (SCBF) in the control group was 12.8 ± 3.51 (SD) ml/min/100 gm on the basis of 107 measurements over 6 hours. In the experimental groups, 16 animals were similarly prepared. The spinal cords of these animals were then traumatized by dropping a 20-gm weight 5 cm (100 gm-cm trauma) or 13 cm (260 gm-cm trauma) onto the T-5 segment. Previous experiments have shown that these trauma levels lead to a transient paraplegia of less than 10 and 30 days' duration, respectively. Two hundred blood flow measurements from T-5 and T-6 were taken over the 6 hours following trauma. In the seven animals of the 100 gm-cm group, mean SCBF after trauma from the T-5 segment was 12.6 ± 3.45 (SD) ml/min/100 gm on the basis of 50 measurements taken over 6 hours; not significantly different from the controls (p > 0.70). In the 260 gm-cm group, mean SCBF from T-5 for 6 hours after trauma was 17.3 ± 6.60 (SD) ml/min/100 gm; significantly higher than controls (p < 0.001). Mean SCBF 3 to 6 hours after trauma was significantly elevated over controls (p < 0.05). The mean hyperemia in the 260 gm-cm group was found to be due to marked hyperemia in only four animals of the series, while five animals maintained blood flows in the normal range. This experiment provides quantitative evidence that white matter ischemia does not occur in spinal cord injuries that can be expected to produce only transient paraplegia. The data support the concept that white matter ischemia in the acute phase of severe spinal cord trauma may be related to secondary injury and subsequent permanent paraplegia.

Effect of a calcium channel blocker on posttraumatic spinal cord blood flow

1987 ◽  
Vol 66 (3) ◽  
pp. 423-430 ◽  
Author(s):  
Abhijit Guha ◽  
Charles H. Tator ◽  
Ian Piper
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Cord Blood ◽  
Whole Blood ◽  
Channel Blocker ◽  
Rat Spinal Cord ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Pressor Agent ◽  
Fine Print

✓ The normal rat spinal cord blood flow (SCBF) has been shown to increase after administration of nimodipine, a calcium channel blocker. The present study investigates the capability of nimodipine to improve SCBF, as measured by the hydrogen clearance technique, after a 53.0-gm clip compression injury to the T-1 segment of the rat spinal cord. The profound drop in mean systemic arterial blood pressure (MSAP) after cervical cord injury precluded any improvement in posttraumatic SCBF by nimodipine alone. Hence, in a randomized controlled study with five rats per group, pressor agents (whole blood, angiotensin, or adrenaline) were infused to maintain MSAP between 100 and 120 mm Hg after injury. Control animals received only a saline infusion. Nimodipine at the optimal dose found in normal animals (1.5 µg/kg/min) was added to the pressor agents. The MSAP and other physiological parameters were measured in rats receiving the pressor agents only and in those receiving pressor agents combined with nimodipine. In rats receiving whole blood, angiotensin, or adrenaline the posttraumatic MSAP improved to between 100 and 120 mm Hg, but there was no improvement in SCBF compared to the saline group. The addition of nimodipine decreased MSAP and SCBF in all groups except those animals also receiving adrenaline, where the MSAP was maintained at 109 ± 5 mm Hg. In these animals a significant increase in posttraumatic SCBF from 16.5 ± 2.1 to 20.2 ± 2.3 ml/100 gm/min (mean ± standard error of the mean) occurred at the site of injury with the addition of nimodipine. The maintenance of an adequate MSAP by a pressor agent was crucial for nimodipine to improve posttraumatic SCBF by its ability to dilate the spinal vascular bed. Adrenalin was the only pressor agent that could fulfill the above criteria, although other pressor agents need to be investigated. Experiments are underway with the combination of adrenaline and nimodipine to further verify these encouraging results demonstrating an improvement in posttraumatic ischemia of the spinal cord.

Effect of laminectomy and anesthesia upon spinal cord blood flow

1984 ◽  
Vol 61 (3) ◽  
pp. 545-549 ◽  
Author(s):  
Patrick W. Hitchon ◽  
Jeffrey M. Lobosky ◽  
Thoru Yamada ◽  
James C. Torner
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Cord Blood ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Radioactive Microsphere ◽  
Radioactive Microsphere Technique ◽  
And Control ◽  
Over Time ◽  
Fine Print

✓ Spinal cord blood flow (SCBF) in 10 sheep subjected to laminectomy at L6–7, T6–7, and C7–T1 was compared to that of 10 control sheep subjected to anesthesia alone. Blood flow was measured using the radioactive microsphere technique, with the PaCO2 maintained at 40 ± 2 mm Hg. Both laminectomy and control animals showed a decrease in SCBF at a rate of 7% to 16%/hr for the 3 hours following the first blood flow determination. When prelaminectomy and postlaminectomy SCBF values were compared to their counterparts in the control animals, there were no significant differences. Laminectomy does not appear to alter SCBF from control values. Spinal evoked potentials (SEP's) were elicited in the laminectomy group by direct cord stimulation at C-7 and L-7. No changes were noted in amplitude or latency of SEP's over time in either caudal or rostral conduction.

The effect of spinal distraction on regional spinal cord blood flow in cats

1980 ◽  
Vol 53 (6) ◽  
pp. 756-764 ◽  
Author(s):  
Eugen J. Dolan ◽  
Ensor E. Transfeldt ◽  
Charles H. Tator ◽  
Edward H. Simmons ◽  
Kenneth F. Hughes
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Cord Blood ◽  
Spinal Cord Injuries ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Cord Injury ◽  
Autoradiographic Technique ◽  
Fine Print

✓ Distraction is considered to be a factor in many spinal cord injuries. With a specially designed distraction apparatus and the 14C-antipyrine autoradiographic technique, the effect of distraction on spinal cord blood flow (SCBF) in cats was studied. Distraction was performed at L2–3 at a rate of 0.25 cm/10 min, and the spinal evoked response (SER) was monitored by stimulating the sciatic nerve and recording at T-13. The SCBF was assessed in five control animals, four animals in whom the SER was markedly altered by distraction, and five animals after the SER had been abolished and an additional 0.5 cm distraction applied. Control cats had gray- and white-matter flows of 44.5 ± 1.4 (SEM) and 10.5 ± 0.4 ml/100 gm/min, respectively. Distraction to the point of marked SER alteration caused a 50% loss of SCBF at and caudal to the distraction site. An additional 0.5 cm distraction produced total abolition of SCBF at the distraction site and for a considerable distance rostral and caudal to it. Thus, it is shown that spinal distraction causes cord ischemia similar to that seen with other types of spinal cord injury. In addition, distraction severe enough to cause loss of the SER has already produced severe cord ischemia.

Increase in rat spinal cord blood flow with the calcium channel blocker, nimodipine

1985 ◽  
Vol 63 (2) ◽  
pp. 250-259 ◽  
Author(s):  
Ab Guha ◽  
Charles H. Tator ◽  
Ian Piper
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Cardiac Output ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Cord Blood ◽  
Channel Blocker ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Fine Print

✓ Nimodipine, a calcium channel blocker, is known to increase cerebral blood flow. In the present study, the authors investigated the effect of nimodipine on spinal cord blood flow in normal rats. Cardiovascular parameters, including mean systemic arterial blood pressure, cardiac output, and heart rate, were recorded during infusion of nimodipine in a dose-response fashion. The experiment was a randomized blind study in which four groups of five rats received different doses of nimodipine (0.001, 0.01, 0.05, and 0.10 mg/kg) intravenously over 30 minutes, and a control group of five rats received only the diluent. The hydrogen clearance and thermodilution techniques were used to measure spinal cord blood flow and cardiac output, respectively. The 0.05-mg/kg dose of nimodipine caused the largest increase in spinal cord blood flow, with a 40% increase over the preinfusion level, although there was a 25% reduction in mean arterial pressure. The 0.10-mg/kg dose did not increase spinal cord blood flow more than the 0.05-mg/kg dose, most likely due to the concomitant 37% reduction in mean arterial pressure. Cardiac output was significantly increased by the 0.05- and 0.10-mg/kg doses secondary to the drop in total peripheral resistance. The increase in spinal cord blood flow produced by nimodipine lasted approximately 20 minutes after the termination of the infusion. Thus, nimodipine at a dose of 0.05 mg/kg markedly increased blood flow in the normal spinal cord even though there were major changes in mean systemic arterial pressure and cardiac output. Further research is required to determine whether this drug might be beneficial in treating ischemic states of the spinal cord, such as posttraumatic ischemia.

Effect of aminophylline and isoproterenol on spinal cord blood flow after impact injury

1980 ◽  
Vol 53 (3) ◽  
pp. 385-390 ◽  
Author(s):  
Diana Dow-Edwards ◽  
Vincent DeCrescito ◽  
John J. Tomasula ◽  
Eugene S. Flamm
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
White Matter ◽  
Cord Blood ◽  
Gray Matter ◽  
Adenosine Monophosphate ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Cord Injury ◽  
Matter Flow

✓ A study of the effects of spinal cord injury upon spinal cord blood flow was carried out in cats. A 400 gm-cm impact produced an overall reduction in spinal cord blood flow of 24% in the white matter and 30% in the gray matter, as determined by 14C-antipyrine autoradiography. At the level of the injury, white-matter flow was 8.1 ml/100 gm/min, a reduction of 49%, and in the gray matter, 12.5 ml/100 gm/min, a reduction of 76%. Treatment with aminophylline and isoproterenol improved the overall blood flow in the spinal cord. At the level of the injury, white-matter flow after this treatment was no longer significantly different from control values. The gray-matter flow remained decreased to 26.2 ml/100 gm/min, a reduction of only 47%. It is proposed that aminophylline and isoproterenol may increase cyclic adenosine monophosphate (AMP) and prevent platelet aggregation along the endothelial surfaces of the microcirculation, and may thereby help to maintain improved perfusion of the injured spinal cord.

Regional spinal cord blood flow in rats after severe cord trauma

1978 ◽  
Vol 49 (6) ◽  
pp. 844-853 ◽  
Author(s):  
Alex S. Rivlin ◽  
Charles H. Tator
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Cord Blood ◽  
Gray Matter ◽  
Albino Rats ◽  
Compression Injury ◽  
Spinal Cord Blood Flow ◽  
Compression Technique ◽  
Content Type ◽  
Cord Injury

✓ Spinal cord blood flow (SCBF) was measured in 12 albino rats following acute cord injury produced by the extradural clip compression technique. Severe injury was produced with the clip compressing the cord with a force of 180 gm for 5 minutes, an injury previously shown to produce a severe functional deficit. Regional SCBF was measured 15 minutes, 2 hours, and 24 hours after injury by the 14C-antipyrine autoradiographic technique and a scanning microscope photometer. At 15 minutes and 2 hours, white and gray matter blood flow was severely diminished, and, at 24 hours, there was only minimal improvement. Focal decreases in blood flow were seen in white and gray matter for a considerable distance proximal and distal to the site of cord trauma. Thus, it has been confirmed in this model that severe cord compression injury produces severe posttraumatic ischemia in the cord which lasts for at least 24 hours.

The effect of nimodipine and dextran on axonal function and blood flow following experimental spinal cord injury

1989 ◽  
Vol 71 (3) ◽  
pp. 403-416 ◽  
Author(s):  
Michael G. Fehlings ◽  
Charles H. Tator ◽  
R. Dean Linden
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Blood Flow ◽  
Compression Injury ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Dextran 40 ◽  
Treatment Groups ◽  
Cord Injury ◽  
Fine Print

✓ There is evidence that posttraumatic ischemia is important in the pathogenesis of acute spinal cord injury (SCI). In the present study spinal cord blood flow (SCBF), measured by the hydrogen clearance technique, and motor and somatosensory evoked potentials (MEP and SSEP) were recorded to evaluate whether the administration of nimodipine and dextran 40, alone or in combination, could increase posttraumatic SCBF and improve axonal function in the cord after acute SCI. Thirty rats received a 53-gm clip compression injury on the cord at T-1 and were then randomly and blindly allocated to one of six treatment groups (five rats in each). Each group was given an intravenous infusion of one of the following over 1 hour, commencing 1 hour after SCI: placebo and saline; placebo and dextran 40; nimodipine 0.02 mg/kg and saline; nimodipine 0.02 mg/kg and dextran 40; nimodipine 0.05 mg/kg and saline; and nimodipine 0.05 mg/kg and dextran 40. The preinjury physiological parameters, including the SCBF at T-1 (mean ± standard error of the mean: 56.84 ± 4.51 ml/100 gm/min), were not significantly different (p > 0.05) among the treatment groups. Following SCI, there was a significant decrease in the SCBF at T-1 (24.55 ± 2.99 ml/100 gm/min; p < 0.0001) as well as significant changes in the MEP recorded from the spinal cord (MEP-C) (p < 0.0001), the MEP recorded from the sciatic nerve (MEP-N) (p < 0.0001), and the SSEP (p < 0.002). Only the combination of nimodipine 0.02 mg/kg and dextran 40 increased the SCBF at T-1 (43.69 ± 6.09 ml/100 gm/min; p < 0.003) and improved the MEP-C (p < 0.0001), MEP-N (p < 0.04), and SSEP (p < 0.002) following SCI. With this combination, the changes in SCBF were significantly related to improvement in axonal function in the motor tracts (p < 0.0001) and somatosensory tracts (p < 0.0001) of the cord. This study provides quantitative evidence that an increase in posttraumatic SCBF can significantly improve the function of injured spinal cord axons, and strongly implicates posttraumatic ischemia in the pathogenesis of acute SCI.

Effect of acute spinal cord compression injury on regional spinal cord blood flow in primates

1976 ◽  
Vol 45 (6) ◽  
pp. 660-676 ◽  
Author(s):  
Alan N. Sandler ◽  
Charles H. Tator
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
White Matter ◽  
Cord Blood ◽  
Gray Matter ◽  
Regional Blood Flow ◽  
Compression Injury ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Cord Injury

✓ Spinal cord blood flow (SCBF) was measured in 24 rhesus monkeys after injury to the cord produced by the inflatable circumferential extradural cuff technique. Measurement of regional blood flow in the white and gray matter of the cord in areas of 0.1 sq mm was achieved with the 14C-antipyrine autoradiographic technique and a scanning microscope photometer. After moderate cord injury (400 mm Hg pressure in the cuff maintained for 5 minutes), which produced paraplegia in 50% of animals and moderate to severe paresis in the other 50%, mean white matter SCBF was significantly decreased for up to 1 hour. White matter blood flow then rose to normal levels by 6 hours posttrauma and was significantly increased by 24 hours posttrauma. Gray matter SCBF was significantly decreased for the entire 24-hour period post-trauma. After severe cord injury (150 mm Hg pressure in the cuff maintained for 3 hours), which produced total paraplegia in almost all animals, SCBF in white and gray matter was reduced to extremely low levels for 24 hours posttrauma. In addition, focal decreases in SCBF were seen in white and gray matter for considerable distances proximal and distal to the injury site. It is concluded that acute compression injury of the spinal cord is associated with long-lasting ischemia in the cord that increases in severity with the degree of injury.

Control of blood flow in the cat spinal cord

1983 ◽  
Vol 58 (5) ◽  
pp. 742-748 ◽  
Author(s):  
Oscar U. Scremin ◽  
Emilio E. Decima
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
White Matter ◽  
Ventral Horn ◽  
Hydrogen Gas ◽  
Lumbar Spinal Cord ◽  
Spinal Cord Tissue ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Fine Print

✓ Spinal cord blood flow (SCBF) and the effect of end-tidal CO2 concentration (ETCO2) on SCBF (CO2 reactivity) were studied in the lumbar spinal cord of cats by means of the hydrogen-clearance technique. Hydrogen gas was administered by inhalation, and its level in spinal cord tissue was estimated amperometrically with small (75 µm) platinum electrodes. The average SCBF's at normocapnia (ETCO2 = 4%) of the ventral horn gray matter and of the white matter at several locations were 43.2 and 16.2 ml·100 gm−1·min−1, respectively. For gray and white matter, the values of CO2 reactivity, estimated by the coefficient of the regression of SCBF (ml·100 gm−1·min−1) on ETCO2 (ml·100 ml−1) were 11.6 and 2.1, respectively. No differences in SCBF or CO2 reactivity were observed between intact animals kept under N2O-O2 ventilation and decerebrated animals with no anesthesia. After an acute spinal section, ventral horn SCBF and CO2 reactivity (measured eight segments below the cordotomy) were not altered, in spite of the profound neural depression present (that is, spinal shock). Orthodromic (dorsal root) stimulation of the ventral horn neurons induced an average increase in blood flow of 128% above control values. Antidromic (ventral root) motoneuron activation failed to produce any significant changes in ventral horn blood flow.

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