Brain Oxygen-Directed Management of Aneurysmal Subarachnoid Hemorrhage. Temporal Patterns of Cerebral Ischemia During Acute Brain Attack, Early Brain Injury, and Territorial Sonographic Vasospasm.

BACKGROUND: Neurocritical management of aneurysmal subarachnoid hemorrhage focuses on delayed cerebral ischemia (DCI) after aneurysm repair. METHODS: This study conceptualizes the pathophysiology of cerebral ischemia and its management using a brain oxygen-directed protocol (intracranial pressure [ICP] control, eubaric hyperoxia, hemodynamic therapy, arterial vasodilation, and neuroprotection) in patients with subarachnoid hemorrhage, undergoing aneurysm clipping (n = 40). RESULTS: The brain oxygen-directed protocol reduced Lbo2 (Pbto2 [partial pressure of brain tissue oxygen] <20 mm Hg) from 67% to 15% during acute brain attack (<24 hours of ictus), by increasing Pbto2 from 11.31 ± 9.34 to 27.85 ± 6.76 (P < 0.0001) and then to 29.09 ± 17.88 within 72 hours. Day-after-bleed, Fio2 change, ICP, hemoglobin, and oxygen saturation were predictors for Pbto2 during early brain injury. Transcranial Doppler ultrasonography velocities (>20 cm/second) increased at day 2. During DCI caused by territorial sonographic vasospasm (TSV), middle cerebral artery mean velocity (Vm) increased from 45.00 ± 15.12 to 80.37 ± 38.33/second by day 4 with concomitant Pbto2 reduction from 29.09 ± 17.88 to 22.66 ± 8.19. Peak TSV (days 7-12) coincided with decline in Pbto2. Nicardipine mitigated Lbo2 during peak TSV, in contrast to nimodipine, with survival benefit (P < 0.01). Intravenous and cisternal nicardipine combination had survival benefit (Cramer Φ = 0.43 and 0.327; G2 = 28.32; P < 0.001). This study identifies 4 zones of Lbo2 during survival benefit (Cramer Φ = 0.43 and 0.3) TSV, uncompensated; global cerebral ischemia, compensated, and normal Pbto2. Admission Glasgow Coma Scale score (not increased ICP) was predictive of low Pbto2 (ß = 0.812, R2 = 0.661, F1,30 = 58.41; P < 0.0001) during early brain injury. Coma was the only credible predictor for mortality (odds ratio, 7.33/>4.8∗; χ2 = 7.556; confidence interval, 1.70-31.54; P < 0.01) followed by basilar aneurysm, poor grade, high ICP and Lbo2 during TSV. Global cerebral ischemia occurs immediately after the ictus, persisting in 30% of patients despite the high therapeutic intensity level, superimposed by DCI during TSV. CONCLUSIONS: We propose implications for clinical practice and patient management to minimize cerebral ischemia.

Partial Brain Tissue Oxygen Levels Predict Arrhythmia and Prognosis in Patients With Brain Injury.

The objective of this study was to examine the clinical determinants of incidence and prognosis of arrhythmias in the setting of acute brain injury. Acute brain injury is known to cause electrocardiographic abnormalities and cardiac arrhythmias. The relation between partial brain tissue oxygen (PBTO) and intracranial pressure (ICP) with arrhythmia incidence and prognosis remains unknown. Consecutive patients with acute brain injury and intracranial bleed admitted to the neurosurgical intensive care unit were enrolled in the study. Baseline characteristics [demographics, medical history, etiology of brain injury, Glasgow Coma Scale (GCS) score, blood pressure, and respiratory rate] were documented. Patient's telemetry recordings were reviewed for daily mean heart rates and arrhythmias. If arrhythmia was noted, PBTO levels at the beginning of arrhythmia, ICP, brain tissue temperature, and outcomes were recorded. A total of 106 subjects (53% men, age 39 ± 18 years, 65 traumatic and 41 nontraumatic brain injuries) were studied. Overall, 62% of subjects developed a total of 241 arrhythmia episodes. Ventricular arrhythmias were associated with significantly higher daily mean heart rates, low PBTO levels, and low GCS scores, whereas atrial arrhythmias were associated with lower daily mean heart rates, normal PBTO levels, and higher GCS and ICP. Three or more episodes of arrhythmia predicted worse outcomes, including mortality (P = 0.001). In patients with acute brain injury, poor PBTO levels are associated with higher incidence of ventricular tachyarrhythmias. In contrast, atrial tachyarrhythmias occur in patients with normal PBTO levels and higher ICP. Incidence of ventricular arrhythmia in those with poor PBTO is associated with increased mortality.

Physiological complexity of acute traumatic brain injury in patients treated with a brain oxygen protocol: utility of symbolic regression in predictive modeling of a dynamical system.

Predictive modeling of emergent behavior, inherent to complex physiological systems, requires the analysis of large complex clinical data streams currently being generated in the intensive care unit. Brain tissue oxygen protocols have yielded outcome benefits in traumatic brain injury (TBI), but the critical physiological thresholds for low brain oxygen have not been established for a dynamical patho-physiological system. High frequency, multi-modal clinical data sets from 29 patients with severe TBI who underwent multi-modality neuro-clinical care monitoring and treatment with a brain oxygen protocol were analyzed. The inter-relationship between acute physiological parameters was determined using symbolic regression (SR) as the computational framework. The mean patient age was 44.4±15 with a mean admission GCS of 6.6±3.9. Sixty-three percent sustained motor vehicle accidents and the most common pathology was intra-cerebral hemorrhage (50%). Hospital discharge mortality was 21%, poor outcome occurred in 24% of patients, and good outcome occurred in 56% of patients. Criticality for low brain oxygen was intracranial pressure (ICP) ≥22.8 mm Hg, for mortality at ICP≥37.1 mm Hg. The upper therapeutic threshold for cerebral perfusion pressure (CPP) was 75 mm Hg. Eubaric hyperoxia significantly impacted partial pressure of oxygen in brain tissue (PbtO2) at all ICP levels. Optimal brain temperature (Tbr) was 34-35°C, with an adverse effect when Tbr≥38°C. Survivors clustered at [Formula: see text] Hg vs. non-survivors [Formula: see text] 18 mm Hg. There were two mortality clusters for ICP: High ICP/low PbtO2 and low ICP/low PbtO2. Survivors maintained PbtO2 at all ranges of mean arterial pressure in contrast to non-survivors. The final SR equation for cerebral oxygenation is: [Formula: see text]. The SR-model of acute TBI advances new physiological thresholds or boundary conditions for acute TBI management: PbtO2≥25 mmHg; ICP≤22 mmHg; CPP≈60-75 mmHg; and Tbr≈34-37°C. SR is congruous with the emerging field of complexity science in the modeling of dynamical physiological systems, especially during pathophysiological states. The SR model of TBI is generalizable to known physical laws. This increase in entropy reduces uncertainty and improves predictive capacity. SR is an appropriate computational framework to enable future smart monitoring devices.

Eubaric hyperoxia: controversies in the management of acute traumatic brain injury.

Controversy exists on the role of hyperoxia in major trauma with brain injury. Hyperoxia on arterial blood gas has been associated with acute lung injury and pulmonary complications, impacting clinical outcome. The hyperoxia could be reflective of the physiological interventions following major systemic trauma. Despite the standard resuscitation of patients with acute traumatic brain injury, up to 60% demonstrate low brain oxygen upon admission to the ICU. While eubaric hyperoxia has been beneficial in experimental studies, clinical brain oxygen protocols incorporating intracranial pressure control, maintenance of cerebral perfusion pressure, and the effective use of fraction of inspired oxygen adjustments to maintain cerebral oxygenation levels >20 to 25 mmHg have demonstrated mortality reductions and improved clinical outcomes. The risk of low brain oxygen is most acute in the first 24 to 48 hours after injury. The administration of a high fraction of inspired oxygen (0.6 to 1.0) in the emergency room may be justifiable until ICU admission for the placement of invasive neurocritical care monitoring systems. Thereafter, fraction of inspired oxygen levels need to be careful titrated to prevent low brain oxygen levels.

Measurements of low oxygen tension in vitro and response of macrophages to levels applicable to peri-and postoperative treatment of traumatic brain injury.

Established clinical guidelines for treatment of severe traumatic brain injury aim at maintaining intracranial and cerebral perfusion pressures. Recently, it has been shown that additional regulation of cerebral oxygen delivery helps to decrease patient mortality and leads to improved 6-month quality-of-life scores. However, eubaric oxygen-guided therapy is still controversial since it is well known that hyperoxia can cause unwanted secondary brain injury. Research studies are warranted to better understand the range of oxygen pressures that positively influence brain cell behavior. We perform such studies using a two-enzyme in vitro system that allows exposing tissue culture cells to various steady-state, or rapidly changing, oxygen pressures. Here, we present a mathematical model of the system and its validation by real-time monitoring of oxygen tensions. We additionally present preliminary evidence that human brain macrophages have a different oxygen tolerance compared to systemic macrophages and propose improvements to our in vitro system to make it applicable for data collection that aim at refining oxygen-guided therapy for patients with traumatic brain injury.

Taming an old enemy: a profile of intracranial suppuration.

Intracranial suppurative disorders (ICSDs; brain abscess, empyema, and purulent ventriculitis), have been a scourge through the ages and attempts at curative surgery, as for cranial trauma, are considered to be one of the first true neurosurgical interventions performed. ICSDs, seen initially as a consequence of poor socioeconomic conditions and neglected otorhinogenic infections, predominantly manifest today as postsurgical complications, and/or in immunocompromised patients where they continue to result in significant neurologic morbidity and death. The reduction in the incidence of "old world" classic ICSDs can be attributed to the modernization of society, driven inter alia by a shift from an agricultural to an industrial economic society. It can also be coupled with pivotal achievements in public health and the dramatic developments in medicine in the 20th century. This trend was first noted in developed countries but now, with improved socioeconomic circumstances and globalization of medical technology, it is occurring in the developing regions of the world as well. Although ICSDs have undergone a metamorphosis in their clinical profile and despite their rarity in contemporary "developed world" neurosurgical practice, they still have undoubted potential for fatal consequences and continue to pose a significant challenge to the 21st-century neurosurgeon.

Brain abscess: management and outcome analysis of a computed tomography era experience with 973 patients.

OBJECTIVE: Brain abscess (BA) is a neurosurgical emergency and despite significant medical advances, it remains a surgical challenge. A single institution's two decade computed tomography era management experience with BA is reported. METHODS: A retrospective analysis of patients with BA, admitted to the Department of Neurosurgery, Wentworth Hospital, Durban, KwaZulu-Natal, South Africa, was performed. The medical records were analyzed for demographic, clinical, neuroimaging, neurosurgical and otolaryngology management, microbiological characteristics, and their relationship to outcome. RESULTS: During a 20-year period (1983-2002), 973 patients were treated. The mean age was 24.36 ± 15.1 years (range: 0.17-72 years) and 74.2% (n = 722) were men. The mean admission Glasgow Coma Score was 12.5 ± 2.83. The majority of BAs were supratentorial (n = 872, 89.6%). The causes were otorhinogenic (38.6%), traumatic (32.8%), pulmonary (7%), cryptogenic (4.6%), postsurgical (3.2%), meningitis (2.8%), cardiac (2.7%), and "other" (8.6%). Surgical drainage was performed in 97.1%, whereas 19 patients had nonoperative management. The incidence of BA decreased during the study period. Patient outcomes were good in 81.3% (n = 791), poor in 5.3% (n = 52), and death (13.4%, n = 130) at discharge. The management morbidity, which included postoperative seizures, was 24.9%. Predictors of mortality were cerebral infarction (odds ratio [OR] 31.1), ventriculitis (OR 12.9), coma (OR 6.8), hydrocephalus (OR 5.1), dilated pupils (OR 4.8), bilateral abscesses (OR 3.8), multiple abscesses (OR 3.4), HIV co-infection (OR 3.2), papilledema (OR 2.6), neurological deterioration (OR 2.4), and fever (OR 1.7). CONCLUSIONS: Optimal management of BA involves surgical drainage for medium-to-large abscesses (≥2.5 cm) with simultaneous eradication of the primary source, treatment of associated hydrocephalus, and administration of high doses of intravenous antibiotics. The incidence of BA is directly related to poor socioeconomic conditions and therefore, still poses a public health challenge in developing countries.

Brain tissue oxygen monitoring in traumatic brain injury and major trauma: outcome analysis of a brain tissue oxygen-directed therapy.

OBJECT: Cerebral ischemia is the leading cause of preventable death in cases of major trauma with severe traumatic brain injury (TBI). Intracranial pressure (ICP) control and cerebral perfusion pressure (CPP) manipulation have significantly reduced the mortality but not the morbidity rate in these patients. In this study, the authors describe their 5-year experience with brain tissue oxygen (PbtO(2)) monitoring, and the effect of a brain tissue oxygen-directed critical care guide (PbtO(2)-CCG) on the 6-month clinical outcome (based on the 6-month Glasgow Outcome Scale score) in patients with TBIs. METHODS: One hundred thirty-nine patients admitted to Creighton University Medical Center with major traumatic injuries (Injury Severity Scale [ISS] scores >or= 16) and TBI underwent prospective evaluation. All patients were treated with a PbtO(2)-CCG to maintain a brain oxygen level > 20 mm Hg, and control ICP < 20 mm Hg. The role of demographic, clinical, and imaging parameters in the identification of patients at risk for cerebral hypooxygenation and the influence of hypooxygenation on clinical outcome were recorded. Outcomes were compared with those in a historical ICP/CPP patient cohort. Subgroup analysis of severe TBI was performed and compared to data reported in the Traumatic Coma Data Bank. RESULTS: The majority of injuries were sustained in motor vehicle crashes (63%), and diffuse brain injury was the most common abnormality (58%). Mechanism of injury, severity of TBI, pathological entity, neuroimaging results, and trauma indices were not predictive of ischemia. Factors affecting death included gunshot injury, poor trauma indices, subarachnoid hemorrhage, and coma. After standard resuscitation, 65% of patients had an initially low PbtO(2). Data are presented as means +/- SDs. Treatment with the PbtO(2)-CCG resulted in a 44% improvement in mean PbtO(2) (16.21 +/- 12.30 vs 23.65 +/- 14.40 mm Hg; p < 0.001), control of ICP (mean 12.76 +/- 6.42 mm Hg), and the maintenance of CPP (mean 76.13 +/- 15.37 mm Hg). Persistently low cerebral oxygenation was seen in 37% of patients at 2 hours, 31% at 24 hours, and 18% at 48 hours of treatment. Thus elevated ICP and a persistent low PbtO(2) after 2 hours represented increasing odds of death (OR 14.3 at 48 hours). Survivors and patients with good outcomes generally had significantly higher mean daily PbtO(2) and CPP values compared to nonsurvivors. Polytrauma, associated with higher ISS scores, presented an increased risk of vegetative outcome (OR 9.0). Compared to the ICP/CPP cohort, the mean Glasgow Outcome Scale score at 6 months in patients treated with PbtO(2)-CCG was higher (3.55 +/- 1.75 vs 2.71 +/- 1.65, p < 0.01; OR for good outcome 2.09, 95% CI 1.031-4.24) as was the reduction in mortality rate (25.9 vs 41.50%; relative risk reduction 37%), despite higher ISS scores in the PbtO(2) group (31.6 +/- 13.4 vs 27.1 +/- 8.9; p < 0.05). Subgroup analysis of severe closed TBI revealed a significant relative risk reduction in mortality rate of 37-51% compared with the Traumatic Coma Data Bank data, and an increased OR for good outcome especially in patients with diffuse brain injury without mass lesions (OR 4.9, 95% CI 2.9-8.4). CONCLUSIONS: The prevention and aggressive treatment of cerebral hypooxygenation and control of ICP with a PbtO(2)-directed protocol reduced the mortality rate after TBI in major trauma, but more importantly, resulted in improved 6-month clinical outcomes over the standard ICP/CPP-directed therapy at the authors' institution.

Collagen matrix duraplasty for posterior fossa surgery: evaluation of surgical technique in 52 adult patients. Clinical article.

OBJECT: Complete dural closure is not always possible following posterior fossa surgery, often requiring a graft to secure complete closure. The authors report their experience of using a collagen matrix as an onlay dural graft for repair of a posterior fossa dural defect. METHODS: A retrospective analysis was performed in 52 adult patients who had undergone collagen matrix duraplasty for the posterior fossa. Complications directly related to the dural graft, the presence or absence of hydrocephalus, and the role of closed suction wound drainage in relation to postsurgical pseudomeningoceles were analyzed. RESULTS: The indication for posterior fossa surgery was tumors in 32 patients, vascular abnormalities in 9 patients, and spontaneous cerebellar hemorrhage in 11 patients. Closed suction wound drainage was used in 23 patients (44.2%). Forty-eight (92.3%) of 52 patients had a dural defect > 2 cm. Nine (81.8%) of 11 patients with hydrocephalus required ventriculoperitoneal shunts. Complications of the surgery included pseudomeningoceles in 2 patients (3.8%; no closed suction wound drainage); superficial wound infections in 1 patient (1.9%; with closed suction wound drainage); and unexplained eosinophilia in 1 patient. CONCLUSIONS: Duraplasty using a collagen matrix is safe and effective in the posterior fossa, and is easy to use and time efficient. Meticulous layered wound closure, the detection and effective control of hydrocephalus, and the use of closed suction wound drainage reduces complications related to collagen matrix duraplasty for the posterior fossa.

Management of hypertensive emergencies in acute brain disease: evaluation of the treatment effects of intravenous nicardipine on cerebral oxygenation.

OBJECT: Inappropriate sudden blood pressure (BP) reductions may adversely affect cerebral perfusion. This study explores the effect of nicardipine on regional brain tissue O(2) (PbtO(2)) during treatment of acute hypertensive emergencies. METHODS: A prospective case-control study was performed in 30 patients with neurological conditions and clinically elevated BP. All patients had a parenchymal PbtO(2) and intracranial pressure bolt inserted following resuscitation. Using a critical care guide, PbtO(2) was optimized. Intravenous nicardipine (5-15 mg/hour) was titrated to systolic BP < 160 mm Hg, diastolic BP < 90 mm Hg, mean arterial BP (MABP) 90-110 mm Hg, and PbtO(2) > 20 mm Hg. Physiological parameters-intracranial pressure, PbtO(2), central venous pressure, systolic BP, diastolic BP, MABP, fraction of inspired O(2), and cerebral perfusion pressure (CPP)-were compared before infusion, at 4 hours, and at 8 hours using a t-test. RESULTS: Sixty episodes of hypertension were reported in 30 patients (traumatic brain injury in 13 patients; aneurysmal subarachnoid hemorrhage in 11; intracerebral and intraventricular hemorrhage in 3 and 1, respectively; arteriovenous malformation in 1; and hypoxic brain injury in 1). Nicardipine was effective in 87% of the patients (with intravenous beta blockers in 4 patients), with a 19.7% reduction in mean 4-hour MABP (115.3 +/- 13.1 mm Hg preinfusion vs 92.9 +/- 11.40 mm Hg after 4 hours of therapy, p < 0.001). No deleterious effect on mean PbtO(2) was recorded (26.74 +/- 15.42 mm Hg preinfusion vs 27.68 +/- 12.51 mm Hg after 4 hours of therapy, p = 0.883) despite significant reduction in CPP. Less dependence on normobaric hyperoxia was achieved at 8 hours (0.72 +/- 0.289 mm Hg preinfusion vs 0.626 +/- 0.286 mm Hg after 8 hours of therapy, p < 0.01). Subgroup analysis revealed that 12 patients had low pretreatment PbtO(2) (10.30 +/- 6.49 mm Hg), with higher CPP (p < 0.001) requiring hyperoxia (p = 0.02). In this group, intravenous nicardipine resulted in an 83% improvement in 4- and 8-hour PbtO(2) levels (18.1 +/- 11.33 and 19.59 +/- 23.68 mm Hg, respectively; p < 0.01) despite significant reductions in both mean MABP (120.6 +/- 16.65 vs 95.8 +/- 8.3 mm Hg, p < 0.001) and CPP (105.00 +/- 20.7 vs 81.2 +/- 15.4 mm Hg, p < 0.001). CONCLUSIONS: Intravenous nicardipine is effective for the treatment of hypertensive neurological emergencies and has no adverse effect on PbtO(2).

Collagen matrix duraplasty for cranial and spinal surgery: a clinical and imaging study.

OBJECT: The repair of dural defects is controversial in contemporary neurosurgery. To date, collagen-based products remain a continued area of interest in the development of dural grafts. The authors conducted a prospective case-control study in which they evaluated collagen matrix in the repair of dural defects following cranial and spinal surgery by using specific clinical and magnetic resonance (MR) imaging outcome measures. METHODS: Enrolled in the study were 79 patients, 36 male (45.6%) and 43 female (54.4%), with a mean age of 53 +/- 15.8 years. The pathological diagnosis was brain tumor in 49 cases (62%), vascular conditions in 16 (20.2%), degenerative spine in 10 (12.7%), trauma in two (2.5%), and other in two (2.5%). Most of the patients underwent supratentorial craniotomy (57; 72.2%), whereas 11 patients (13.9%) each underwent posterior fossa and spinal surgery. Sixty-three patients (79.7%) completed the study, which included clinical and MR imaging evaluations at 3 months postsurgery. There were no cerebrospinal fluid (CSF) leaks or delayed hemorrhages. The neurosurgical wound infection rate was 3.8%: superficial wound infection in two cases and deep infection and brain abscess in one case (recurrent brain tumor following radiation therapy). Among the 63 patients in whom 3-month postsurgery imaging data were available, asymptomatic small pseudomeningoceles were detected on MR imaging in two (3.2%); a minor subgaleal fluid collection, which resolved spontaneously, was apparent in another patient (1.6%). Nonspecific dural enhancement was demonstrated on images obtained in seven patients (11.1%), and asymptomatic spinal epidural enhancement was observed on images obtained in two of three patients who had undergone lumbar laminectomy for spinal stenosis. CONCLUSIONS: When used as a dural onlay graft, collagen matrix had a 100% CSF containment rate but might be associated with occult radiological abnormalities.

Cerebral oxygenation in major pediatric trauma: its relevance to trauma severity and outcome.

INTRODUCTION: Trauma is the commonest cause of death in the pediatric population, which is prone to diffuse primary brain injury aggravated by secondary insults (eg, hypoxia, hypotension). Standard monitoring involves intracranial pressure (ICP) and cerebral perfusion pressure, which do not reflect true cerebral oxygenation (oxygen delivery [Do(2)]). We explore the merits of a brain tissue oxygen-directed critical care guide. METHODS: Sixteen patients with major trauma (Injury Severity Score, >16/Pediatric Trauma Score [PTS], <7) had partial pressure of brain tissue oxygen (Pbto(2)) monitor (Licox; Integra Neurosciences, Plainsboro, NJ) placed under local anesthesia using twist-drill craniostomy and definitive management of associated injuries. Pbto(2) levels directed therapy intensity level (ventilator management, inotrops, blood transfusion, and others). Patient demographics, short-term physiological parameters, Pbto(2), ICP, Glasgow Coma Score, trauma scores, and outcomes were analyzed to identify the patients at risk for low Do(2). RESULTS: There were 10 males and 6 females (mean age, 14 years) sustaining motor vehicle accident (14), falls (1), and assault (1), with a mean Injury Severity Score of 36 (16-59); PTS, 3 (0-7); and Revised Trauma Score, 5.5 (4-11). Eleven patients (70%) had low Do(2) (Pbto(2), <20 mm Hg) on admission despite undergoing standard resuscitation affected by fraction of inspired oxygen, Pao(2), and cerebral perfusion pressure (P = .001). Eubaric hyperoxia improved cerebral oxygenation in the low-Do(2) group (P = .044). The Revised Trauma Score (r = 0.65) showed moderate correlation with Pbto(2) and was a significant predictor for low Do(2) (P = .001). In patients with Pbto(2) of less than 20 mm Hg, PTS correlated with cerebral oxygenation (r = 0.671, P = .033). The mean 2-hour Pbto(2) and the final Pbto(2) in survivors were significantly higher than deaths (21.6 vs 7.2 mm Hg [P = .009] and 25 vs 11 mm Hg [P = .01]). Although 4 of 6 deaths were from uncontrolled high ICP, PTS and 2-hour low Do(2) were significant for roots for mortality. CONCLUSIONS: Pbto(2) monitoring allows for early recognition of low-Do(2) situations, enabling appropriate therapeutic intervention.

Collagen matrix (DuraGen) in dural repair: analysis of a new modified technique.

STUDY DESIGN: Retrospective review of 110 patients undergoing spinal dural repair and regeneration using an onlay, suture-free, 3-dimensional-collagen matrix graft (DuraGen) over an 8-year period (1995-2003). OBJECTIVES: Technique appraisal of collagen matrix to repair spinal dura following incidental durotomy, spinal tumor surgery, and trauma. SUMMARY OF BACKGROUND DATA: Traditional methods of spinal dural repair following incidental durotomy involve tedious attempts at primary watertight suture with a 5% to 10% failure rate. Dural injury occurs after trauma, or dural excision may be required after tumor resection. Collagen matrix is a newer development in collagen sponge. METHODS: The clinical and demographic data included diagnosis, type and site of surgery, infection risk, size of defect, use of lumbar drains, closed suction subfascial drains, and adverse events. The primary endpoints of graft failure were cerebrospinal fluid leak and pseudomeningocele formation. Neurosurgical wound infection rates were determined. RESULTS: Collagen matrix was used (n = 110) in the following conditions: degenerative (69), pseudomeningocele formation repair (4), tumors (14), trauma (13), and congenital (5). There were 15 cervical (10 anterior), 21 thoracic (3 anterior), and 71 lumbar (all posterior) surgeries. Fibrin glue was used in 7.3%, subfascial drains in 82%, and lumbar drainage in 2.7%. Overall, cerebrospinal fluid leaks occurred in 2.7%. The 2 pseudomeningocele formations (3.2%) resolved at 3 months. There were 2 wound infections. In the subgroup with incidental durotomy (n = 69), failure of cerebrospinal fluid containment occurred in 4.3% [1 cerebrospinal fluid leak (1.4%), 2 pseudomeningocele formations (2.9%)]. CONCLUSIONS: Collagen matrix was successful in cerebrospinal fluid containment in > 95% of patients requiring dural repair following anterior and posterior spinal surgery. Subfascial drains were safe. Routine lumbar drains are not required but are recommended for repair of established pseudomeningocele formations.

Influence of apoptosis on neurological outcome following traumatic cerebral contusion.

OBJECT: Apoptosis has increasingly been implicated in the pathobiology of traumatic brain injury (TBI). The present study was undertaken to confirm the presence of apoptosis in the periischemic zone (PIZ) of traumatic cerebral contusions and to determine the role of apoptosis, if any, in neurological outcome. METHODS: Brain tissue harvested at Wentworth Hospital from the PIZ in 29 patients with traumatic supratentorial contusions was compared with brain tissue resected in patients with epilepsy. Immunohistochemical analyses were performed on the tissues to see if they contained the apoptosis-related proteins p53, bcl-2, bax, and caspase-3. The findings were then correlated to demographic, clinical, surgical, neuroimaging, and outcome data. In the PIZ significant increases of bax (18-fold; p < 0.005) and caspase-3 (20-fold; p < 0.005) were recorded, whereas bcl-2 was upregulated in only 14 patients (48.3%; 2.9-fold increase) compared with control tissue. Patients in the bcl-2-positive group exhibited improved outcomes at the 18-month follow-up examination despite an older mean age and lower mean admission Glasgow Coma Scale score (p < 0.03). Caspase-3 immunostaining was increased in those patients who died (Glasgow Outcome Scale [GOS] Score 1, 12 patients) when compared with those who experienced a good outcome (GOS Score 4 or 5, 17 patients) (p < 0.005). Regression analysis identified bcl-2-negative status (p < 0.04, odds ratio [OR] 5.5; 95% confidence interval [CI] 1.1-28.4) and caspase-3-positive status (p < 0.01, OR 1.4, 95% CI 1.1-1.8) as independent predictors of poor outcome. No immunostaining for p53 was recorded in the TBI specimens. CONCLUSIONS: The present findings confirm apoptosis in the PIZ of traumatic cerebral contusions and indicate that this form of cell death can influence neurological outcome following a TBI.

Titanium mesh cages for cervical spine stabilization after corpectomy: a clinical and radiological study.

OBJECT: Reconstruction after anterior cervical decompression has involved the use of tricortical iliac crest bone or fibular strut grafts, but has been associated with significant morbidity. In this study the authors evaluated the efficacy of titanium mesh cages (TMCs) for stability and fusion following anterior cervical corpectomy. METHODS: Thirty-seven patients were prospectively evaluated during a 4-year period. The majority presented with spinal cord compression (97%) often due to cervical spondylosis (87%). The TMC was filled with iliac crest bone chips or Surgibone and stabilized by anterior cervical plates (ACPs). The changes in settling ratio, coronal and sagittal angles, and sagittal displacement were determined at 3, 6, and 12 months; immediate postoperative radiographs were used as baseline. Flexion-extension radiographs and computerized tomography (CT) scans (obtained at 1 year) were examined to assess stability, fusion, and bone growth within the TMC. Complications such as settling, telescoping, migration, and pseudarthrosis were not observed. Dynamic radiography revealed spinal stability in all patients. Cage-related complications occurred in 2.7% (TMC malplacement [one patient]), surgery-related complications in 10.8%, and graft-related complications in 21.6%. Evidence of bone growth into the TMC was documented in 16 (95%) of 17 patients on CT scans. The mean cage height-related settling rates were 4.46% at 3 months (31 patients [p = 0.066]), 3.89% at 6 months (28 patients [p = 0.028]), and 4.35% at 1 year (27 patients [p = 0.958]). The mean sagittal displacement changed by 3.9% (23 patients [p = 0.73]). The mean coronal and sagittal angles changed 2.89 degrees (30 patients [p = 0.498]) and 2.09 degrees (29 patients [p = 0.001]) at 1 year, respectively, or at last follow up from baseline. No significant differences in the radiological indices were seen when multilevel vertebrectomy cases were compared with single-level vertebrectomy (p = 0.221), smoking status, or age. Conclusions. Titanium mesh cages, in combination with ACPs, are safe and effective for vertebral replacement in the cervical spine.