Endoscopy-assisted cerebral falx incision via unilateral approach for treatment of dissymmetric bilateral frontal contusion

Objective: To investigate the clinical features and treatment strategy of dissymmetric bilateral frontal contusion,and to summarize our experience in treating these patients by minimally invasive surge...     

单额开颅治疗双额叶挫裂伤伴血肿

目的总结单额开颅治疗双额叶挫裂伤的经验。方法回顾性分析21例双额叶挫裂伤患者的临床资料,均采用单额开颅治疗。入院时GCS评分:9～11分13例,6～8分6例,3～5分2例。结果术后第1 d所有病例均行头颅CT复查,无一例出现迟发性颅内血肿或残余血肿。对侧挫裂伤及血肿基本清除(>75%)15例,部分清除(50%～75%)6例。术后6个月按GOS分级标准,恢复良好13例,中残4例,重残3例,死亡1例。结论采用单额开颅能有效清除双额叶挫裂伤及血肿,并具有缩短手术时间、减轻手术创伤等优点,具有较好的临床实用价值。     

Delayed traumatic vasospasm: correlation between cerebral vasospasm and contusion]

The pathogenesis of delayed traumatic vasospasm is not yet fully understood. We present six cases of delayed traumatic symptomatic vasospasm along with CT scan and angiographic findings. The cases ranging in age from 16 to 78 years all had head injury caused by traffic accidents. The Glasgow coma scale on admission was 9 - 15 except in one severe case GCS 6. Initial CT scans were obtained on the day of injury in four patients and on the 2nd and 3rd days in the other two cases respectively. There was no distinct subarachnoid hemorrhage in the suprasellar cistern. Subarachnoid hemorrhage in the Sylvian cistern was observed with particular care in all patients. However the severity of subarachnoid hemorrhage was mild (isodensity or slight high density by CT) in 4 cases. Brain contusions on CT scan were observed in the temporal and/or frontal region of 5 of 6 patients. Ischemic symptoms occurred during the period between 5 and 13 days after head injury. The cerebral angiogram taken after the occurrence of these symptoms revealed spasms in all patients, the spasm being bilateral in 2 of them. Spasms were recognized on the main arteries at the base of the brain such as C1, M1, M2 and A1. In 5 cases, the cerebral contusion and the spasm were located on the same side. Angiographically the vasospasms lasted 2 to 5 weeks. The prognosis based on the Glasgow outcome scale was good recovery in 3 patients and moderate disability in one. Two elderly patients with bilateral spasms were in a vegetative state and severe disability, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pulmonary contusions in patients with rib fractures: The need to better classify a common injury

BackgroundPulmonary contusions are common injuries. Computed tomography reveals vast contused lung volume spectrum, yet pulmonary contusions are defined dichotomously (unilateral vs bilateral). We assessed whether there is stepwise increased risk of pulmonary complications among patients without, with unilateral, and with bilateral pulmonary contusion.MethodsWe identified adults admitted with rib fractures using the largest US inpatient database. After propensity-score-matching patients without vs with unilateral vs bilateral pulmonary contusions and adjusting for residual confounders, we compared risk for pneumonia, ventilator-associated pneumonia (VAP), respiratory failure, intubation, and mortality.ResultsAmong 148,140 encounters of adults with multiple rib fractures, 19% had concomitant pulmonary contusions. Matched patients with pulmonary contusions had increased risk of pneumonia 19% [95%CI:16–33%], respiratory failure 40% [95%CI: 31–50%], and intubation 46% [95%CI: 33–61%]. Delineation showed bilateral contusions, not unilateral contusions, attributed to increased risk of complications.ConclusionsThere is likely a correlation between contused lung volume and risk of pulmonary complications; dichotomously classifying pulmonary contusions is insufficient. Better understanding this correlation requires establishing the clinically significant contusion volume and a correspondingly refined classification system.     

The Effect of Implementation of Guidelines for the Management of Severe Head Injury on Patient Treatment and Outcome

The authors retrospectively analysed two groups of consecutive patients who were similarly matched for brain injury severity. From a total of 39 severe head injury patients, 23 were treated according to the Guidelines for the Management of Severe Head Injury with intracranial pressure (ICP) monitoring ("Guidelines group"). Such an approach allowed the maintenance of ICP within normal values, especially in patients with intraventricular ICP monitoring allowing the release of cerebrospinal fluid (CSF) from the ventricular system. In the Guidelines group only two patients were administered barbiturates, after all other means of ICP lowering had been exhausted. The second group consisted of 16 patients who were not monitored for ICP ("non-Guidelines group"). In this group, management consisted of the prophylactic administration of barbiturates, high dose osmotic diuretics and hyperventilation usually at levels below 25 mm Hg. In the Guidelines group the mortality rate was 30% compared to 44% in the non-Guidelines group. Almost twice as many patients achieved a "favourable" (good recovery and moderate disability) outcome (49%) compared to the non-Guidelines treated patients (25%). Furthermore, there was a 32% decrease in severe neurological disabilities in those patients in the Guidelines group. It seems that the implementation of "Guidelines" in the treatment of severe head injury, based on the result of our clinical study, reduces death and disability rates in patients with severe head injury. The administration of therapy based on the "Guidelines principles" and monitoring of ICP, can minimise the application of those therapeutic modalities (barbiturate coma and prolonged hyperventilation) which, in addition to favourable effects, may also have harmful effects on patients with severe head injury.     

Neuropathological findings in disabled survivors of a head injury

We investigated how the occurrence and severity of the main neuropathological types of traumatic brain injury (TBI) influenced the severity of disability after a head injury. Eighty-five victims, each of whom had lived at least a month after a head injury but then died, were studied. Judged by the Glasgow Outcome Scale (GOS), before death 35 were vegetative, 30 were severely and 20 were moderately disabled. Neuropathological assessment showed that 71 (84%) victims had sustained cerebral contusions, 49 (58%) had diffuse axonal injury (DAI), 57 (67%), had ischemic brain damage (IBD), 58 (68%) had symmetrical ventricular enlargement, and in 47 (55%) intracranial pressure (ICP) had been increased. Thirty-five (41%) had undergone evacuation of an intracranial hematoma. Brainstem damage was seen in only 11 (13%). Analysis (χ(2) test for trends) of the relationship between these features and outcome showed that findings of DAI, raised ICP, thalamic damage, or ventricular enlargement (all p<0.005), and IBD (p=0.04) were associated with an increasingly worse outcome. Conversely, moderate or severe contusions (p=0.001) were increasingly associated with better outcomes, and evacuation of a hematoma was associated (p=0.001) with outcomes likely to be better than vegetative. We conclude that diffuse or multifocal neuropathological patterns of TBI from primary axonal injury or secondary ischemic damage are most likely to be associated with the most severely impaired outcomes after a head injury.     

The Brain Trauma Foundation. The American Association of Neurological Surgeons. The Joint Section on Neurotrauma and Critical Care. Indications for intracranial pressure monitoring

ICP monitoring per se has never been subjected to a prospective randomized clinical trial (PRCT) to establish its efficacy (or lack thereof) in improving outcome from severe head injury. Hence, there are insufficient data to support its use as a standard. However, there is a large body of published clinical experience that indicates that ICP monitoring (1) helps in the earlier detection of intracranial mass lesions, (2) can limit the indiscriminate use of therapies to control ICP which themselves can be potentially harmful, (3) can reduce ICP by CSF drainage and thus improve cerebral perfusion, (4) helps in determining prognosis, and (5) may improve outcome. ICP monitoring is therefore used by most head injury experts in the United States and is accepted as a relatively low-risk high-yield, modest cost intervention. Comatose head injury patients (GCS 3-8) with abnormal CT scans should undergo ICP monitoring. Comatose patients with normal CT scans have a much lower incidence of intracranial hypertension unless they have two or more of the following features at admission: age over 40, unilateral or bilateral motor posturing, or a systolic blood pressure of less than 90 mm Hg. ICP monitoring in patients with a normal CT scan with two or more of these risk factors is suggested as a guideline. Routine ICP monitoring is not indicated in patients with mild or moderate head injury. However, it may be undertaken in certain conscious patients with traumatic mass lesions at the discretion of the treating physician.     

Effects of intravenous anesthesia with propofol on regional cortical blood flow and intracranial pressure in surgery for moyamoya disease

BACKGROUND: The aim of this study was to compare the effects of inhalation anesthesia with sevoflurane and intravenous anesthesia with propofol on ICP and rCoBF during revascularization surgery for patients with MMD. METHODS: Between 1999 and 2004, a total of 90 revascularization surgeries were performed on 58 patients. Among them, in 20 consecutive operations on 14 patients, continuous monitoring of ICP was performed with an ICP monitoring probe. Subsequently, in 14 consecutive operations on 9 patients (CoBF group), intraoperative monitoring of rCoBF was carried out with a laser Doppler flowmeter probe. The monitoring of ICP and rCoBF was performed for more than 20 minutes after the administration of anesthetic was changed from 1.5% to 2.5% sevoflurane to 6 mg/kg per hour of propofol. In all cases, the Paco(2) of these patients was strictly maintained between 38 and 40 mm Hg throughout the operations. RESULTS: In both the ICP and the CoBF groups, the values of physiologic parameters obtained under inhalation anesthesia did not differ statistically from those obtained under intravenous anesthesia. The value for ICP under anesthesia with propofol was significantly lower than that under anesthesia with sevoflurane (P < .0001). The value for rCoBF in the frontal lobe under anesthesia with propofol was significantly higher than that under anesthesia with sevoflurane. CONCLUSIONS: Intravenous anesthesia with propofol has potential to provide brain protection and preservation of rCBF in the frontal lobes in surgery for MMD. Whether choice of anesthetic agents might be important in surgery for MMD should be investigated further.     

The geometry of brain contusion: relationship between site of contusion and direction of injury

Up to a fifth of Accident and Emergency admissions are head-injury related. Alcohol is involved in a large proportion of adult head injuries and although the incidence of death due to head injury (HI) is relatively low, long-term sequelae including cognitive disturbance are frequent. Contrecoup contusions (CCs) have been observed commonly in closed head injuries and may be an independent factor in long-term neuro-disability. The mechanisms of their formation are still under debate. The aim of this study was to define the relationship between the direction of the blow to the head and the location of brain contusion after HI. The location of scalp injuries was used as a surrogate for the direction of the blow to the head. Between January 2007 and March 2009, 358 cases of HI were treated at the Newcastle Neurosurgery Unit. Of these, 129 had contusions. Of these, 100 scans were available. The site of scalp injury could be identified in 98 cases and these were used for the study. Sixty-six percent of scalp injuries were to the back of the head. Most contusions (77%) were contracoup affecting the frontal and temporal lobes. Sixty percent of the injuries were inflicted by a fall from a standing position striking the back of the head on a paved surface, most commonly in the context of assaults or fighting.     

Clinical applications of intracranial pressure monitoring in traumatic brain injury

Background

Intracranial pressure (ICP) monitoring has been for decades a cornerstone of traumatic brain injury (TBI) management. Nevertheless, in recent years, its usefulness has been questioned in several reports. A group of neurosurgeons and neurointensivists met to openly discuss, and provide consensus on, practical applications of ICP in severe adult TBI.

Methods

A consensus conference was held in Milan on October 5, 2013, putting together neurosurgeons and intensivists with recognized expertise in treatment of TBI. Four topics have been selected and addressed in pro-con presentations: 1) ICP indications in diffuse brain injury, 2) cerebral contusions, 3) secondary decompressive craniectomy (DC), and 4) after evacuation of intracranial traumatic hematomas. The participants were asked to elaborate on the existing published evidence (without a systematic review) and their personal clinical experience. Based on the presentations and discussions of the conference, some drafts were circulated among the attendants. After remarks and further contributions were collected, a final document was approved by the participants.

Summary and conclusions

The group made the following recommendations: 1) in comatose TBI patients, in case of normal computed tomography (CT) scan, there is no indication for ICP monitoring; 2) ICP monitoring is indicated in comatose TBI patients with cerebral contusions in whom the interruption of sedation to check neurological status is dangerous and when the clinical examination is not completely reliable. The probe should be positioned on the side of the larger contusion; 3) ICP monitoring is generally recommended following a secondary DC in order to assess the effectiveness of DC in terms of ICP control and guide further therapy; 4) ICP monitoring after evacuation of an acute supratentorial intracranial hematoma should be considered for salvageable patients at increased risk of intracranial hypertension with particular perioperative features.     

Bilateral Traumatic Intracranial Hematomas and its Outcome: a Retrospective Study

The objective of this study was to evaluate the age distribution, mode of injury, type of hematomas, and their surgical outcome in patients with bilateral traumatic head injuries. The present study included 669 cases of traumatic head injury who presented at the neurosurgery emergency out of which 94 cases had bilateral head injuries from the period of August 2009 to April 2014. The data from the hospital computerized database were retrospectively analysed. Cases of bilateral traumatic head injury included 94 patients out of which 88.29 % (n?=?83) were males and 11.70 % (n?=?11) were females. Commonest mode of injury was road traffic accident in 56.38 % (n?=?53) followed by fall from height in 29.78 % (n?=?28). In our study, 25.53 % patients had epidural hematoma (EDH) with intracerebral hematoma (ICH) or contusion (n?=?24), followed by EDH with subarachnoid hemorrhage (SAH) in 18.08 % (n?=?17). At the time of discharge, all those patients managed conservatively had good Glasgow outcome scale (GOS) while with surgical intervention 58 % patients had good GOS, 19 % had moderate disability, and 9 % remained with severe disability. In cases of bilateral hematomas, EDH is most common and should be managed in neurosurgical emergency. Other combinations of bilateral intracranial hematomas should be managed according to the surgical indication and serial CT imaging.     

Extracellular glycerol in patients with severe traumatic brain injury

Objective： To study the factors affecting extracellular glycerol （Gly） in patients with severe traumatic brain injury （STBI）.
Methods： Perilesional extracellular Gly and cerebral blood flow （CBF） in 53 patients with STBI were consecutively monitored. Simultaneously, the intracranial pressure （ICP） and cerebral perfusion pressure （CCP） were monitored. The hourly minimum of CCP and CBF and the hourly maximum of ICP levels were matched with the hourly Gly. Gly values were divided into several groups according to regional ICP （〈 15 nun Hg or 〉 15 nun Hg）, CCP （〈70 nun Hg or 〉70 nun Hg）, CBF （〈50 AU or 50-150 AU） and the outcomes （death or persistent vegetative state group, severe or moderate disability group, and good recovery group）.
Results： In comparison with the severe or moderate disability group, the Gly concentration of the death or persistent vegetative state group increased significantly, but CBF and CCP decreased significantly. In comparison with the good recovery group, the Gly concentration of the severe or moderate disability group increased significantly, but CBF and CCP decreased significantly. The Gly concen- trations in patients with ICP〉15 mm Hg, CCP〈70 mm Hg and CBF〈50 AU were respectively higher than those of patients with ICP 〈15 mm Hg, CCP〉70 mm Hg and 50AU 〈CBF〈150AU. In patients with diffuse axial injury, the mean Gly concentration was （201.17±55.00） μmol/L, which was significantly higher than that of the patients with epidural hematoma （n=7, 73.26±8.37, P〈O.05） or subdural hematoma （n=9, 114.67 ±62.88, P〈O.05）, but it did not increase signifi- cantly when compared with those in patients with contusion （n=24, 167.48±52.63）.
Conclusion： Gly can be taken as a marker for degrada- tion of membrane phospholipids and ischemia, which reflects the severity of primary or secondary insult.     

Neural injury and recovery near cortical contusions: a clinical magnetic resonance spectroscopy study

OBJECT: Proton magnetic resonance (MR) spectroscopy can detect neural metabolic alterations noninvasively after traumatic brain injury (TBI) even in areas that appear normal. Unlike metabolic depression in diffuse TBI, focal metabolic alterations near cortical contusions in humans have not been previously investigated in a longitudinal study. The object of this study was to identify these alterations and examine their course. METHODS: At 1 week and 1 month after mild to moderate TBI involving cortical contusion, 30 patients underwent 1H MR spectroscopy examination that focused bilaterally on normal-appearing frontal and temporal white matter. Levels of N-acetylaspartate (NAA), choline (Cho) compounds, and creatine (Cr) were measured to obtain two metabolite ratios, NAA/Cr and Cho/Cr. The ratios were compared with those of 11 healthy individuals. At 1 week after TBI, the NAA/Cr ratio was significantly lower near cortical contusions than it was in white matter remote from the injury or in controls, while the Cho/Cr ratios did not differ significantly. At 1 month, the decreased NAA/Cr ratios near contusions had increased significantly from 1 week, as had the Cho/Cr ratio. CONCLUSIONS. Metabolic depression reflecting neural injury was apparent in subjacent normal-appearing white matter at 1 week after cortical contusion; this had normalized substantially at 1 month.     

Normal computed tomograms in acute head injury: correlation of intracranial pressure, ventricular size, and outcome

To assess the predictive value of a normal computed tomographic (CT) scan obtained shortly after head injury, we reviewed all cases of patients with acute closed injury seen at the North Carolina Baptist Hospital over a 42-month period for whom initial CT scanning and continuous intracranial pressure (ICP) monitoring had been done. Of 160 patients meeting those criteria, the initial CT scan was interpreted as normal in 17 patients, all of whom had a Glasgow coma scale score of 9 or less. Of those 17 patients, 7 had elevated ICP (higher than 25 mm Hg) and required mannitol. Six of the 7 had a major pulmonary injury. From the 27 CT scans of the 17 patients, we calculated an inverse cella media index and compared it to previously published standards in an attempt to delineate more quantitatively the "slit ventricles" often seen in cases of head injury. Two patients died of extracranial injuries; I had severe disability and 2 had moderate disability - all related to extracranial factors. The remaining 12 made good recoveries. From these findings, we conclude that a normal initial CT scan in patients with closed head injury and pulmonary injury does not preclude increased ICP (and thus should not preclude ICP monitoring) and that patients with closed head injury and a normal initial CT scan in the absence of associated extracranial injuries should make a good recovery.     

Use of intraoperative ultrasonography to improve the diagnostic accuracy of exploratory burr holes in patients with traumatic tentorial herniation

Seventeen head-injured patients with signs of brain stem compression at admission underwent emergency bilateral burr-hole exploration before computerized tomographic (CT) scanning. After exploration of the epidural and subdural spaces, real-time ultrasonography was performed intraoperatively to identify intraaxial hematomas. Epidural or subdural hematomas were identified surgically in 11 patients (65%) and immediately evacuated through a craniotomy; in 2 patients, bilateral subdural hematomas were removed. Ultrasonography showed no evidence of intracerebral mass lesions in 14 (82%) of the 17 patients, demonstrated extensive contusions of the temporal lobe in 2 patients (prompting partial lobectomy in both cases), and revealed a small intraparenchymal hematoma deep within the dominant hemisphere, which was not removed, in 1 patient. The sensitivity of ultrasound images for identifying intraparenchymal lesions was evaluated postoperatively by CT or autopsy. In 15 patients (88%), the results of ultrasonography were confirmed. In 2 (12%), CT scans showed small but significant lesions at the frontal pole missed by ultrasonography; one patient had a residual subdural hematoma, and the other a small intraparenchymal hemorrhage. These results confirm that patients with clinical evidence of brain stem compression soon after head injury often have extraaxial hematomas that can be readily identified by burr-hole exploration. Although intraparenchymal hematomas are rare immediately after head injury, they can usually be identified by intraoperative ultrasonography. This simple technique can reduce the risk of missing intracranial hematomas during emergency burr-hole exploration and improve intraoperative decision making in this population of severely head-injured patients.     

一侧开颅清除双侧额叶挫裂伤伴出血

目的探讨一侧开颅切开额前部大脑镰清除双侧额叶挫裂伤的手术治疗可行性。方法对8例经一侧开颅清除双侧额叶挫裂伤的病例进行回顾性分析。结果术后CT复查示所有病例血肿清除满意,出院GOS评分7例为良好,1例并肺部感染自动出院。结论一侧开颅清除双侧额叶挫裂伤具有创伤小、手术时间短、失血少、患者预后好的优点,对部分病例适用。     

Post-operative expansion of hemorrhagic contusions after unilateral decompressive hemicraniectomy in severe traumatic brain injury

Decompressive hemicraniectomy is commonly performed in patients with traumatic brain injury (TBI) with diffuse brain swelling or refractory raised intracranial pressure. Expansion of hemorrhagic contusions in TBI patients is common, but its frequency following decompressive hemicraniectomy has not been well established. The aim of this retrospective study was to determine the rate of hemorrhagic contusion expansion following unilateral hemicraniectomy in severe TBI, to identify factors associated with contusion expansion, and to examine whether contusion expansion is associated with worsened clinical outcomes. Computed tomography (CT) scans of 40 consecutive patients with non-penetrating TBI who underwent decompressive hemicraniectomy were analyzed. Hemorrhagic contusion volumes were measured on initial, last pre-operative, and first post-operative CT scans. Mortality and 6-month Glasgow Outcome Scale (GOS) score were recorded. Hemorrhagic contusions of any size were present on the initial head CT scan in 48% of patients, but hemorrhagic contusions with a total volume of >5 cc were present in only 10%. New or expanded hemorrhagic contusions of >or=5 cc were observed after hemicraniectomy in 58% of patients. The mean volume of increased hemorrhage among these patients was 37.1+/-36.3 cc. The Rotterdam CT score on the initial head CT was strongly associated with the occurrence and the total volume of expanded hemorrhagic contusions following decompressive hemicraniectomy. Expanded hemorrhagic contusion volume greater than 20 cc after hemicraniectomy was strongly associated with mortality and poor 6-month GOS even after controlling for age and initial Glasgow Coma Scale (GCS) score. Expansion of hemorrhagic contusions is common after decompressive hemicraniectomy following severe TBI. The volume of hemorrhagic contusion expansion following hemicraniectomy is strongly associated with mortality and poor outcome. Severity of initial CT findings may predict the risk of contusion expansion following hemicraniectomy, thereby identifying a subgroup of patients who might benefit from therapies aimed at augmenting the coagulation system.     

Head and face injuries in bicyclists--with special reference to possible effects of helmet use.

Fatal and nonfatal head and face injuries to unhelmeted bicyclists were analyzed to assess the injury-reducing potential of bicycle helmet use. Of the fatally injured, 64% (median age, 55 years) had fatal head and face injuries compared with 38% (median age, 18 years) with head and face injuries in the nonfatal injury group. The fatally injured often had multiple impact points, mostly to the occipital and temporal regions. Brain contusions, most often to the frontal and temporal lobes, were the most common cause of fatal injury, followed by subdural hematomas. In the nonfatal injury group abrasions/lacerations were most common type of injury, followed by cerebral concussions/contusions and superficial contusions. If all types of injuries to bicyclists are taken into account a helmet might have had an injury-reducing effect in two of every five fatal cases and in one of every five nonfatal cases. To increase the helmet use among bicyclists, a law, as in Australia, would be an excellent instrument.     

家犬额叶出血模型的建立及颅内压监测

目的 建立一种存活时间长且简单易行的额叶脑出血(ICH)模型,并运用该模型研究ICH后ICP变化特点.方法 选择雄性成年家犬12只,随机分为ICH组和生理盐水注入对照组,每组6只.运用Medtronic神经导航系统校正额叶注血部位及角度建立家犬额叶ICH动物模型,监测血糖、血气分析、脑温,并观察模型制备前1 h和模型制备后2、6、24 h,3、7、14d动物行为学及ICP,以及实验结束时脑组织病理学变化.结果 两组所监测血糖、血气分析和脑温差异无统计学意义(P>0.05);与对照组比较,ICH组动物行为学改变表现更重;ICH模型制备后2 h,两组均出现ICP峰值,之后逐渐下降,对照组3 d即恢复正常,而ICH组至14 d ICP仍明显高于基线数值(P<0.05)和对照组(P<0.01);ICH组血肿周围脑水肿和神经元损伤较对照组严重.结论 本实验建立的家犬额叶ICH模型可以较好反映ICH后ICP变化过程.     

Effect of cerebral perfusion pressure on contusion volume following impact injury

OBJECT: Although it is generally acknowledged that a sufficient cerebral perfusion pressure (CPP) is necessary for treatment of severe head injury, the optimum CPP is still a subject of debate. The purpose of this study was to investigate the effect of various levels of blood pressure and, thereby, CPP on posttraumatic contusion volume. METHODS: The left hemispheres of 60 rats were subjected to controlled cortical impact injury (CCII). In one group of animals the mean arterial blood pressure (MABP) was lowered for 30 minutes to 80, 70, 60, 50, or 40 mm Hg 4 hours after contusion by using hypobaric hypotension. In another group of animals the MABP was elevated for 3 hours to 120 or 140 mm Hg 4 hours after contusion by administering dopamine. The MABP was not changed in respective control groups. Intracranial pressure (ICP) was monitored with an ICP microsensor. The rats were killed 28 hours after trauma occurred and contusion volume was assessed using hematoxylin and eosin-stained coronal slices. No significant change in contusion volume was caused by a decrease in MABP from 94 to 80 mm Hg (ICP 12+/-1 mm Hg), but a reduction of MABP to 70 mm Hg (ICP 9+/-1 mm Hg) significantly increased the contusion volume (p < 0.05). A further reduction of MABP led to an even more enlarged contusion volume. Although an elevation of MABP to 120 mm Hg (ICP 16+/-2 mm Hg) did not significantly affect contusion volume, there was a significant increase in the contusion volume at 140 mm Hg MABP (p < 0.05; ICP 18+/-1 mm Hg). CONCLUSION: Under these experimental conditions, CPP should be kept within 70 to 105 mm Hg to minimize posttraumatic contusion volume. A CPP of 60 mm Hg and lower as well as a CPP of 120 mm Hg and higher should be considered detrimental.