Consensus statement from the international consensus meeting on post-traumatic cranioplasty.

BACKGROUND: Due to the lack of high-quality evidence which has hindered the development of evidence-based guidelines, there is a need to provide general guidance on cranioplasty (CP) following traumatic brain injury (TBI), as well as identify areas of ongoing uncertainty via a consensus-based approach. METHODS: The international consensus meeting on post-traumatic CP was held during the International Conference on Recent Advances in Neurotraumatology (ICRAN), in Naples, Italy, in June 2018. This meeting was endorsed by the Neurotrauma Committee of the World Federation of Neurosurgical Societies (WFNS), the NIHR Global Health Research Group on Neurotrauma, and several other neurotrauma organizations. Discussions and voting were organized around 5 pre-specified themes: (1) indications and technique, (2) materials, (3) timing, (4) hydrocephalus, and (5) paediatric CP. RESULTS: The participants discussed published evidence on each topic and proposed consensus statements, which were subject to ratification using anonymous real-time voting. Statements required an agreement threshold of more than 70% for inclusion in the final recommendations. CONCLUSIONS: This document is the first set of practical consensus-based clinical recommendations on post-traumatic CP, focusing on timing, materials, complications, and surgical procedures. Future research directions are also presented.

Thyrotropin-releasing hormone: stimulation of colonic activity following intracerebroventricular administration.

Intraventricularly administered thyrotropin-releasing hormone in rabbits elicited an increase in intraluminal pressure changes, a response commonly associated with muscular activity of the colon. The response appears to be central in origin with peripheral expression relying primarily on cholinergic receptors.

Influence of thyrotropin releasing hormone (TRH) on drug-induced narcosis and hypothermia in rabbits.

Thyrotropin releasing hormone (TRH) administered via the intracerebroventricular (icv) route in doses ranging between 0.1 and 100 mug decreased the duration of pentobarbital-induced narcosis in rabbits. Antagonism of narcosis occurred whether TRH was administered before or after the barbiturate. TRH doses above 10 mug produced, in addition, behavioral excitation and hyperthermia. The antagonism of phenobarbital-induced narcosis was not as profound; animals were aroused only for a short period of time, after which the narcotized state returned. However, TRH exerted a prolonged antagonism or reversal of the phenobarbital-induced hypothermia. The central nervous system depression and analgesia produced by morphine were unaffected by TRH, but hypothermia and respiratory depression were reversed. TRH may represent an arousal factor in mammalian brain.

Actions of GABA in developing rabbit hippocampus: an in vitro study.

The development of neuronal responses to gamma-aminobutyric acid (GABA) was examined using intracellular recording techniques in area CA1 of rabbit hippocampal slices maintained in vitro. Microapplication of GABA (via pressure ejection) in stratum pyramidale in slices from mature rabbits (age 1 month) evoked a hyperpolarization of CA1 pyramidal neurons. The reversal potential (Erev) for this response was approximately -70 mV. In contrast, local application of GABA into stratum pyramidale in slices from immature rabbits (age 7-10 days) produced a depolarizing response with an Erev of approximately -54 mV. The relationship between these findings and the development of inhibitory synaptic activity in rabbit hippocampus is discussed.

Effects of droperidol, pentobarbital, and ketamine on myogenic transcranial magnetic motor-evoked responses in humans.

Myogenic motor-evoked responses to transcranial magnetic stimulation of the motor cortex (tcmag-MERs) may become clinically useful for the noninvasive assessment of motor pathway conduction during surgery. However, application is hindered because most anesthetic regimens result in severe depression of tcmag-MER amplitudes. As part of our systematic attempts to identify anesthetic agents and supplements suitable for use during tcmag-MER recording, we studied the effect of bolus doses of pentobarbital (1.5 mg/kg), droperidol (0.07 mg/kg), or ketamine (1 mg/kg), administered intravenously, on compound muscle action potentials to transcranial magnetic stimulation in five healthy volunteers. The doses were chosen to be comparable with doses that might be suitable for supplementation of a nitrous oxide/opioid anesthetic technique. Droperidol administration resulted in sustained amplitude depression of both tibialis and adductor pollicis tc-MERs to 30 +/- 9% and 39 +/- 14% of baseline (P < 0.01). Tcmag-MER amplitude changes after pentobarbital were variable, ranging from no change to substantial amplitude depression (to 20% of baseline) in two subjects. In contrast, ketamine administration did not result in significant amplitude depression. In three subjects, tibialis anterior amplitude increased to 150 to 220% of control values in the first 10 minutes after ketamine. Onset latency was unchanged after any drug. These data indicate that tcmag-MERs are moderately depressed after droperidol and pentobarbital but well preserved after ketamine. Ketamine may be a more suitable supplement to opioid/nitrous oxide anesthesia than droperidol or pentobarbital.

The localizing value of asymmetry in pupillary size in severe head injury: relation to lesion type and location.

Reliable Assessment of the probability that a head injury patient harbors a surgical intracranial lesion is critical to both triage and treatment. The authors analyzed data from 608 patients with severe head injuries (Glasgow Coma Scale score, < or = 8) in the Traumatic Coma Data Bank to assess the reliability of pupillary asymmetry in predicting the presence and location of an intracranial mass lesion. Of 210 patients with pupillary asymmetry of > or = 1 mm, 63 (30%) had intracranial mass lesions, 52 (25%) of which were extra-axial in location, 38 (73%) of these located ipsilateral to the larger pupil. Of 51 patients with asymmetry of > or = 3 mm, 22 (43%) had intracranial mass lesions, 18 (35%) of which were extra-axial in location, 14 (64%) of these located ipsilateral to the larger pupil. For both asymmetry categories, strong interactions were found with age and mechanism of injury, the highest incidence of extra-axial lesions occurring in older patients injured other than as occupants of motor vehicles. The authors developed regression equations that provide a graphic means to predict the presence of an intracranial hematoma using data on pupillary asymmetry, age, and mechanism of injury. This predictive model, interpreted in a hospital- and patient-specific fashion, should be of significant use in directing triage, activating diagnostic and therapeutic resources, and evaluating the utility of exploratory trephination.

Cervical conjoined nerve root variant: preoperative imaging and surgical conformation. Case report.

A case of a nerve root anomaly in a patient presenting with cervical radiculopathy is presented. The patient was treated with posterolateral exploration and decompression, resulting in relief of pain and improvement in strength. Both the preoperative contrast-enhanced computerized tomography scan and the magnetic resonance image demonstrated an abnormality behind the C-4 body extending from the right C3-4 neural foramen to the neural foramen at C4-5. At surgery, a dural-encased structure was discovered connecting the C-4 and C-5 nerve roots within the spinal canal. This paper describes the first reported case of a cervical nerve root anomaly of this type, representing a variant of a conjoined nerve root. The occurrence of such nerve root anomalies in the cervical spine should be entered into the differential diagnosis and treatment of cervical radiculopathy.

Extracranial complications of severe head injury.

In order to define the role of intracranial and extracranial complications in determining outcome from severe head injury, 734 patients from the Traumatic Coma Data Bank were analyzed. Nine classes of intracranial and 13 classes of extracranial complications occurring within the first 14 days after admission were analyzed, while controlling for age, admission Glasgow Coma Scale motor score, early hypoxia or hypotension, and severe extracranial trauma. Outcome for survivors was based on the last recorded Glasgow Outcome Scale score, obtained a median of 521 days after injury. Intracranial complications did not significantly alter outcome for the study group. Of the extracranial complications, pulmonary, cardiovascular, coagulation, and electrolyte disorders occurred most frequently at 2 to 4 days. Infections developed later, peaking at 5 to 11 days. Gastrointestinal, renal, and hepatic complications followed no specific time course. Electrolyte abnormalities were the most frequent occurrence (59% of patients) but did not alter outcome. Pulmonary infections (41%), shock (29%, systemic blood pressure < or = 90 mm Hg for 30 minutes or more), coagulopathy (19%), and septicemia (10%) were significant independent predictors of an unfavorable outcome. Backward-elimination, stepwise logistic regression modeling indicated that the estimated reduction of unfavorable outcome was 2.9% for the elimination of pneumonia, 3.1% for coagulation disturbances, 1.5% for septicemia, and 9.3% for shock. These data suggest that extracranial complications are highly influential in determining the outcome from severe head injury and that significant improvements in outcome in a sizeable proportion of patients could be accomplished by improving the ability to prevent or reverse pneumonia, hypotension, coagulopathy, and sepsis.

Metallic spinal artifacts in magnetic resonance imaging.

STUDY DESIGN: The magnetic resonance artifact susceptibility of traces of surgical aluminum, titanium, and stainless steel in a human spine model was investigated. Metallic filings were deposited in noncontiguous disc spaces in five human thoracic spines before magnetic resonance imaging with spin echo and gradient echo sequences. OBJECTIVES: Spin echo and gradient echo sequences were used for quantitate and compare void artifact produced by commonly used surgical metals. This was compared to a liquid paraffin control. SUMMARY OF BACKGROUND DATA: No significant susceptibility artifact was seen with any metal in all spin echo sequences, including T1 (TR 600, TE 12), T2 (TR 2000, TE 30), proton density (TR 2000, TE 80), and fast T2 scanning (TR 3800, TE 96, Ef). METHODS: Sagittal magnetic resonance imaging permitted void artifact quantification and comparison between different metallic alloys. Two neuroradiologists, working on a blinded basis, evaluated all data and rated the void susceptibility artifact on a scale of 1 (least) to 4 (greatest). RESULTS: In general, the magnitude of an imaging artifact during magnetic resonance imaging correlated with the magnetism of the metal. Nickel, found in a larger concentration in 316L than in 304 stainless steel, decreases the magnetic resonance artifact of specific metals because of its ability to stabilize iron in a non-magnetic state. Therefore, the 316L stainless steel yielded less artifact production than 304 stainless steel on gradient echo imaging. CONCLUSION: If upon gradient echo imaging in the postoperative period significant artifact production is noted, stainless steel deposition should be suspected as the causative agent. In this situation, spin echo techniques should be the first approach for attempting optimal visualization of the spinal cord and soft tissue structures.

Myogenic motor-evoked potential monitoring using partial neuromuscular blockade in surgery of the spine.

STUDY DESIGN: The authors analyzed motor-evoked potentials using transcranial electrical cortical stimulation during spinal surgery in 40 patients under conditions of partial neuromuscular blockade. OBJECTIVES: The results were used to investigate the utility of motor-evoked potential monitoring to prevent neurologic injury in spinal surgery. SUMMARY OF BACKGROUND DATA: Noninvasive transcranial electrical motor-evoked potentials are reportedly effective in predicting postoperative spinal cord deficits caused by intraoperative occurrences. However, the sensitivity and specificity of these predictions have not been assessed under conditions of partial neuromuscular blockade during a wide variety of surgical procedures. METHODS: Compound muscle action potentials were recorded at the tibialis anterior muscle while general anesthesia was maintained with nitrous oxide, etomidate, and sufentanil. Surgery was performed at all spinal levels for a variety of diagnoses. RESULTS: Reference motor-evoked potential amplitudes, measured after induction of partial neuromuscular blockade, ranged from 25 to 7562 microV (median, 600 microV). Variation in intraoperative motor-evoked potential amplitude ranged from signal loss to a 3440% increase. A decrease to less than 20% of the individual reference value for motor-evoked potential amplitude occurred at least once in nine patients (22.5%) but as not associated with postoperative motor deficits. Two patients who had loss of motor-evoked potential signal without recovery did have postoperative motor deficits. Motor-evoked potentials predicted postoperative motor improvement in six patients. An improvement threshold of 160% of the reference amplitude predicted postoperative motor improvement with 100% sensitivity and 81% specificity. CONCLUSIONS: The authors support the utility of recording transcranial electrical motor-evoked potentials in spinal surgery under partial neuromuscular blockade. Recovery of lost motor-evoked potentials was not associated with postoperative motor deficits, whereas non-recovery of lost motor-evoked potentials was.

Intracranial pressure. Monitoring and management.

Monitoring of ICP from the subarachnoid, intraparenchymal, or ventricular spaces can be accomplished easily and reliably. The risks and benefits of each approach should be considered when choosing the monitoring technique. The goal of ICP management is to prevent herniation and to optimize cerebral perfusion. Even transient episodes of post-traumatic cerebral ischemia due to inadequate CPP can quickly nullify all resuscitative efforts. The provision of sufficient CBF is complicated by the varying degree of disruption of pressure autoregulation commonly resulting from head trauma. Post-injury, there is a need to provide a CPP which is elevated to some extent with respect to that sufficient in uninjured brains. This generally requires a CPP of at least 70 mm Hg, which must be accomplished by maintaining an adequate MAP while controlling ICH. Although ICH can generally be controlled using methods commonly employed, the majority of these techniques have potential complications. Additionally, there is increasing evidence that significant variation exists in the pathologic processes driving ICH in individual patients. Therefore, goals such as the desired CPP and conditions such as the relative contribution of edema, cerebral hypervolemia, and ischemia to ICH should optimally be considered in a patient-specific fashion and allow a targeted approach to therapy.

Management of head injury. Treatment of abnormal intracranial pressure.

Intracranial hypertension is recognized as a fundamental pathophysiologic process in brain injury. Although the exact pressure level defining intracranial hypertension remains to be firmly established, the majority of evidence available currently suggests that ICP should generally be treated when it exceeds 20 mm Hg. We suggest that lesions in the temporal lobe be treated at 15 mm Hg owing to the special relationship of this region to the brain stem. Along with the individual intracranial pressure reading, however, the course of the pressure over time and the status of the intracranial compliance as reflected in the ICP waveform must be considered when evaluating the intracranial dynamics. There is mounting evidence that patients with intracranial hypertension may comprise a heterogeneous group and that subgroups differ in their optimal treatment strategies. Although we cannot as yet identify such groups, factors such as age, CT diagnosis, responsiveness to hyperventilation, pressure-volume index, and ICP waveform are emerging as important differentiating factors. In particular, young patients with absent perimesencephalic cisterns and a tight brain on CT scan who manifest intracranial hypertension may comprise a group more suitable for treatment with hyperventilation and hypnotics than with osmotic agents. Although this is yet to be firmly established, currently it should be considered when such a patient responds poorly early in the course of conventional therapy for raised ICP. Treatment of intracranial hypertension remains rooted in the conventional therapeutic maneuvers. Maintenance of the basic homeostatic state of the patient is to be supplemented with head elevation, sedation, pharmacologic paralysis, hyperventilation, CSF drainage, and osmotic therapy as indicated. Outside of the special considerations discussed earlier, barbiturates should only be considered in patients with refractory intracranial hypertension without preexisting cardiovascular contraindications. Although several other agents have shown promise, currently the most exciting agent appears to be etomidate, which may prove quite useful. As ICP is better defined and understood, many significant and experimentally approachable questions are recognized. The basic mechanisms of raised ICP are slowly becoming elucidated. Clinical clues with which to subdivide patients with intracranial hypertension are being defined. New agents with efficacy in lowering raised ICP are appearing, and determination of their mechanisms of action may provide insight into the underlying disorder.

Surgical management of cervical radiculopathy. Indication, techniques, and results.

Cervical radiculopathy can be surgically approached either posteriorly or anteriorly and the anterior approach has been described with or without fusion. The choice of approach and technique must be based upon anatomic, pathophysiologic, and biomechanical principles in addition to the familiarity of the surgeon with the procedures. The authors discuss the use of the posterior approach for lateral soft-disk disease because it minimizes disruption of soft and bony tissues and does not markedly disrupt the biomechanics of the cervical spine. The anterior approach is preferred for radiculopathy involving osteophytic hard-disk disease, and when properly and carefully performed, the addition of an interbody fusion holds significant advantages over diskectomy without fusion.

The management of severe traumatic brain injury.

An approach to the initial evaluation, resuscitation, and treatment of the patient with severe traumatic brain injury is presented in terms of the underlying physiology and literature support. The primary importance of rapid and complete systemic resuscitation in terms of the "ABCs" is stressed, with the goal of optimizing cerebral perfusion and preventing secondary insults to the injured brain. The integration of brain-specific treatments and diagnostic maneuvers into resuscitation protocols is discussed, including the role of mannitol and hyperventilation as well as the prioritization of CT imaging of the brain.

A lesson learned from jugular venous oximetry.

The authors describe the case of a severely head injured patient whose profound cerebral infarction was clearly indicated by prolonged desaturation on jugular venous oximetry. Shortly thereafter jugular venous oxygen saturation returned to normal stable values and measured within normal limits for the next 24 h. As demonstrated by a computed tomography (CT) scan, these values appear to have represented a jugular mixture of significant amount of cerebral blood that had passed through infarcted tissue and remained highly saturated. This is a very graphic example of the misleading influence that regional flow-metabolic inhomogeneities can have on jugular venous saturation and it emphasizes that cerebral ischemia can be easily missed if no information on cerebral blood flow or regional metabolism is available.

Evidence of case management effect on traumatic-brain-injured adults in rehabilitation.

The purpose of this study was to evaluate the evidence for effectiveness of case management during recovery from traumatic brain injury (TBI) in adults. After an overview of TBI incidence, prevalence, and problems, and a brief explanation of case management, the study methods are described, the findings are discussed and recommendations are made for future research. Medline, HealthSTAR, CINAHL, PsychINFO, and the Cochrane Library databases were searched and 83 articles met the criteria for review. The strongest studies (n = 3) were critically appraised and their design features and data were placed in two evidence tables. Due to methodological limitations, there was neither clear evidence of effectiveness nor of ineffectiveness. For future research, we recommend controlled research designs, standardization of measures, adequate statistical analysis and specification of health outcomes of importance to persons with TBI and their families.

Intracerebral abscess associated with the Camino intracranial pressure monitor: case report and review of the literature.

BACKGROUND AND IMPORTANCE: Intracranial pressure (ICP) monitoring is a mainstay in the management of traumatic brain injury. Large investigations have validated the safety and efficacy of ICP monitors in comatose patients. Clinically relevant infections are extremely rare and cerebral abscess has never been reported with the Camino device. We describe an exceptional case of a life-threatening intracerebral abscess from an intraparenchymal ICP monitor. CLINICAL PRESENTATION: A 35-month-old child required 7 days of ICP monitoring after a fall from a 2-story window. His hospital course was complicated by severe airway edema treated, in part, with high-dose corticosteroid therapy for a total of 10 days. Two weeks later, the patient deteriorated acutely owing to a large intracerebral abscess under the previous ICP monitor site. Urgent craniotomy with evacuation of the abscess was performed on 2 separate occasions. Cultures grew methicillin-sensitive Staphylococcus aureus, which was treated with long-term antibiotics. At the 3-month follow-up, the patient was meeting age-appropriate milestones without focal deficits. CONCLUSION: To the best of our knowledge, this is the first report describing an intracerebral abscess as a complication from an intraparenchymal pressure monitor. Corticosteroid therapy may have constituted an independent risk factor for the ICP monitor--associated infection, as well as reinsertion of the ICP monitoring device at the same site. That this is the first reported parenchymal infectious complication underscores the safety of this device with respect to infection. When reinsertion of a parenchymal monitor is considered, a new site should be chosen.