头颅外伤和脑卒中治疗新方法

New Approaches to Treatment of Head Trauma and Stroke
Disclosures
Antonios Liolios, MD
Introduction
　　 Despite impressive advances in the field of neurosurgery, intracranial hypertension continues to be a very difficult and even lethal complication. The adult brain is contained in the rigid cranial vault so only minimal increases in volume and, consequently, in pressure are tolerated. Additionally, the brain is one of the softest and most vulnerable tissues in the human body. It then appears intuitive to attempt to restore normal intracranial pressures (ICPs) by removing the barrier, the rigid skull. Thomas Bleck, MD,[1] of the University of Virginia Medical Center in Charlottesville, Virginia, discussed the origin, the evolution, and the clinical applicability of this concept.
　　Craniectomy holes have been found in ancient human skulls. It was thought that by opening a hole in the human head, the evil spirits tormenting the patient with headache would come out. Sir Victor Horsley in the 19th century and Cushing in 1905 have advocated craniectomy for the relief of high ICP. Since then, there has been a substantial increase in interest as well as pertinent papers on craniectomy. There are 3 major types of craniectomy: lateral temporal or frontotemporal, bifrontal, and suboccipital (reserved for cerebellar hematoma or swelling).
Craniectomy has also been studied in cases of acute subdural hematoma by Ransohoff and colleagues.[2] In this small series, 35 patients (all with abnormal posturing and abnormal pupils) were treated with craniectomy, and a significant decrease in mortality was reported compared with historical controls (60% vs 80% to 90%).
　　Massive intracranial edema is another area where craniectomy may be lifesaving. It appeared as a therapeutic option in 1971 in the work of Kjellberg and coworkers.[3] In this series, 73 patients were operated on; 13 patients (18%) survived with 5 of them having an excellent survival. Sixteen others also showed definite improvement, but died afterwards for other medical reasons.
In a more recent study of severe refractory posttraumatic intracranial edema, Polin and associates[4] studied 35 patients and compared them with 140 patients from the Traumatic Coma Data Bank. Patients who underwent decompression craniectomy had significantly lower postoperative ICP (P = .0003). A better outcome was evident when the procedure was performed before the ICP value exceeded 40 mm Hg and within 48 hours of the time of injury.
　　Early craniectomy has reduced significantly infarct volume and neurologic outcome in experimental animal cases of stroke. A follow up study also confirmed the beneficial effects early craniectomy had on neurologic outcome.[5]
　　In humans, early hemicraniectomy has been also studied in patients with complete middle cerebral artery infarction. In this prospective study, 63 patients received either early (less than 24 hours) or late craniectomy (more than 24 hours), and their outcomes were compared with historical controls. An impressive decrease in mortality was demonstrated in both groups; it was more pronounced in the early craniectomy group (16% for early craniectomy and 34% for late craniectomy compared with 78% for historical controls). Additionally, despite complete hemispheric infarction, no patients who underwent craniectomy developed complete hemiplegia.[6]

Figure 1. Postoperative CT showing infarcts and midline shift at the level of the septum. Courtesy of Thomas P. Bleck, MD, FCCM, Neuroscience Critical Care Unit, University of Virginia.

Figure 2. Postoperative CT showing infarcts and midline shift at the level of the pineal. Courtesy of Thomas P. Bleck, MD, FCCM, Neuroscience Critical Care Unit, University of Virginia.

Figure 3. Postcraniectomy CT showing reversal of midline shift at the level of the septum. Courtesy of Thomas P. Bleck, MD, FCCM, Neuroscience Critical Care Unit, University of Virginia.

Figure 4. Postcraniectomy CT showing reversal of midline shift at the level of the pineal. Courtesy of Thomas P. Bleck, MD, FCCM, Neuroscience Critical Care Unit, University of Virginia.
A very recent study[7] attempted to define the indications and the timing for craniectomy. A total of 18 patients with massive cerebral edema treated with decompressive craniectomy were studied. A preoperative computed tomography (CT) scan showed signs of transtentorial herniation, subarachnoid hemorrhage, and malignant middle cerebral artery infarction, which had a significant association with mortality or with a poor outcome. Patients with focal hematomas had better outcomes.
The importance of early rehabilitation for stroke patients has recently been extensively recognized. Despite appropriate applied rehabilitation measures, recovery from stroke continues to be disappointing; clearly, more efficient approaches are distressingly needed.
　　New Approaches to Stroke Recovery
　　Use of Hypothermia in Management of Stroke
　　Questions and Answers

Conclusions
Uncontrolled ICP continues to be a major problem in the care of the head-injured or stroke patient. Despite the numerous available approaches, none is totally effective, and there are still patients dying of uncontrollable intracranial hypertension today. Craniectomy offers a radical approach to the problem by relieving the constricting effect of the rigid surrounding bony structures. It is probably an underutilized and understudied technique, requiring considerable surgical skill and carrying a significant potential for complications. No consensus exists so far and the recommendations for early craniectomy, except in the case of life-threatening brain edema, are unclear. Even in these cases, timing is a concern. What is also unclear is the outcome and subsequent quality of life of the rescued patients. It is hoped that the ongoing studies will clarify these issues until a less invasive approach is found.
Hypothermia is another promising technique for ICP control. It requires special equipment and trained personnel so not every medical center can apply it. Significant complications, especially infections and arrhythmias, are associated with its use. For now, it is regarded as an adjuvant therapy for uncontrollable ICP management, with unclear indications for less severe cases.
Finally, long-term motor recovery is feasible and should be aggressively pursued in stroke patients. Remaining healthy brain tissue recruitment is observed by functional MRI, and brain compensation and/or induction is considered the plausible explanation. Repetitive, continuous, low energy-load exercise has the most beneficial effect on chronic stroke patients, challenging the concept that functional recovery is time-limited in such cases.
In conclusion, given the current dismal prognosis of brain-injured or stroke patients, craniectomy and hypothermia should be comprehensively studied as potentially useful adjuncts in the management of high ICP. Patients entering the chronic phase after brain injury should be aggressively treated with appropriate physical therapy and rehabilitation.
References
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2. Ransohoff J, Benjamin MV, Gage EL Jr, et al. Hemicraniectomy in the management of acute subdural hematoma. J Neurosurg. 1971;34:70-76.
3. Kjellberg RN, Prieto A. Bifrontal decompressive craniotomy for massive cerebral edema. J Neurosurg. 1971;34:488-493.
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