LMC journal Vol. 2.indd 111 Penetra ng brain injury Sharma AP Department of Surgery, Lumbini Medical College and Teaching Hospital, Tansen-11, Pravas, Palpa, Lumbini Zone, Nepal Corresponding author: Prof. Achyut Prasad Sharma, FRCS(Ed), Neurosurgeon and Head Department of Surgery, Lumbini Medical College and Teaching Hospital, Tansen-11, Pravas, Lumbini Zone, Nepal; e-mail: achyut-s@hotmail.com ABSTRACT In the past 20 years, there has been an increase in the incidence of head injuries caused by gunshot wounds. Penetra ng brain injury is a trauma c brain injury caused by high-velocity projec les or low-velocity sharp objects. A wound in which the projec le breaches the cranium but does not exit is referred as a penetra ng wound, and an injury in which the projec le passes en rely through the head, leaving both entrance and exit wounds, is referred to as a perfora ng wound. A large number of these pa ents who survive their ini al wounding will nevertheless expire shortly a er admission to the hospital. Un l the introduc on of asep c surgery in the last quarter of the nineteenth century, penetra ng missile injuries of the brain were almost universally fatal. We have learned a great deal about gunshot wounds and their management from military experience gained during mes of war, when a large number of fi rearm-related casual es are treated in a short period of me.1 Newly designed protec ve body armor has reduced the incidence of penetra ng brain injuries signifi cantly. Many of the vic ms in the vicinity of a cased explosive or an improvised explosive device will incur injuries by fragments. Blast injury is a common mechanism of trauma c brain injury among soldiers serving in war zone. Each war has had diff erent lessons to teach. World War I for example, proved the effi cacy of vigorous surgical interven on. During World War II, the importance of ini al dural repair and an bio c medica on was fi rst, debated, then acknowledged, and fi nally, universally accepted. The incidence of blast-induced trauma c brain injury has increased substan ally in recent military confl icts. Blast-induced neurotrauma is the term given to describe an injury to the brain that occurs a er exposure to a blast. Resent confl ict has exposed military personnel to sophis cated explosive devices genera ng blast overpressure that results in secondary cellular and molecular insults to the brain parenchyma akin to diff use brain injury. In soldiers with varying amounts of body armor, the pa ern is quite diff erent. What had previously been fatal penetra ng brain injuries now become treatable brain injuries as a consequence of secondary damping of energy by the helmet. Trauma c brain injury is not prevented by a protec ve helmet. High- and low-frequency blast waves disrupt the blood-brain barrier and produce massive brain swelling in a very short me, thereby necessita ng urgent decompressive craniectomy, and when low in energy, such blast waves may result in cytoskeletal and diff use axonal injury that leads to neurodegenera on. Penetra ng trauma c brain injury is typically iden fi ed and treated immediately mild trauma c brain injury may be missed, par cularly in the presence of other more obvious injuries. In recent years there has been an apparent paradigm shi of scien fi c interest in long-term eff ects of mild trauma c brain injury and its contribu on to pos rauma c stress disorder.1,¹4 The introduc on of Guidelines for the Management of Penetra ng Brain Injury has revolu onized the medical and surgical management of penetra ng brain injury during the last decade¹. There has been a paradigm shi toward a less aggressive debridement of deep seated fragments and a more aggressive an bio cs prophylaxis in an eff ort to improve outcomes. Keywords: Penetra ng brain injury, debridement, less aggressive surgical management. INTRODUCTION Gunshot wounds are a major health problem. Many deaths are due to gunshot wounds to the head, which are the most lethal. In the spring of 1998, the Interna onal Brain Injury Associa on, the Brain Injury Associa on, USA, the American Associa on of Neurological Surgeons, and the congress of Neurological Surgeons began work on the formula on of standard medical and surgical management for penetra ng brain injury pa ents. Thus, Guidelines for the Management of Penetra ng Brain Injury was published in 2001, which a empted to standardize both the medical and surgical management of penetra ng craniocerebral trauma. Op mum management of penetra ng brain injury requires a good understanding of ballis c characteris cs of the wounding agents and the mechanism of wounding and the ssue damage and adherence to basic surgical principles are prerequisites to a carefully executed and defi ni ve surgical management, when indicated¹. BALLISTICS AND PATHOLOGY A fi rearm is any weapon that uses an explosive powder to propel a projec le. Firearms are classifi ed based on their size, their muzzle velocity and type of projec le fi red. The ability of bullets, shrapnel, and low velocity Reveiw Article L M Coll J 2013; 1(2): 111-116 112 Journal of Lumbini Medical College objects such as knives and arrow to penetrate the brain is dependent on their energy, shape, the angle of approach, and characteris cs of intervening ssues. Primary injury to the brain is determined by the ballis c proper es. There are three components to ballis cs: interior, exterior and terminal. The behavior of a projec le on impac ng its target is terminal ballis cs. Interior ballis cs is defi ned as the science of mo on of a projec le through a gun barrel as a result of combus on and expansion of a powder charge. Exterior ballis cs is the projec le’s behavior in a medium such as air and is dependent on the projec le’s shape, caliber, weight, ini al velocity, and ballis c coeffi cient. Most handguns and revolvers use heavy bullets and have muzzle veloci es ranging from 550 to 900 /sec. These are referred to as low velocity missiles. In contrast, most of today’s rifl es use very light bullets and have muzzle veloci es averaging 3000 /sec, with a range of 2300 to 6000 /sec. The wounding energy (E) of a projec le depends mainly on its weight and velocity; hence, E= ½M (VI²- VR²), where M is the projec le’s weight, VI is the impact velocity, and VR is the residual velocity if the projec le has a perfora ng mode. Transla on of kine c energy into tissue damage is brought about by the tremendous amount of crushing pressure exerted on the brain parenchyma. Juxtamissile pressure aff ects the brain ssue immediately in the path of a projec le and may be in the thousands of atmospheres. Longitudinal strong shock waves start immediately a er impact of the projec le with brain ssue and travel in spheres ahead of the projec le with veloci es in excess of 1460m/sec. Shock waves last up to 10 μsec and measure up to 80 atm. Ordinary pressure waves measuring up to 20 to 30 atm are generated as the projec le transfers its kine c energy to the surrounding brain tissue and produces a temporary cavity. The nega ve pressure generated by the temporary cavity can suck contaminated material into the cavity. Every cycle of temporary expansion and collapse creates signifi cant surrounding ssue injury to the brain.6,11 This can result in shear-like injury of the neurons or can result in epidural hematomas, subdural hematomas, or parenchymal contusions. The low-velocity sharp objects, which lack any defi nable ballis cs, penetrate the scalp, skull, and dura and lacerate the brain parenchyma, including the cortex, subcor cal white ma er, basal ganglia, and diencephalon or brain stem and any blood vessels in their path. Similarly, low-velocity projec les from ar llery shells, improvised explosive devices, and spent bullets cut into the brain just like sharp objects do. Fragments of high-explosive devices are of various shapes and sizes and can weigh as much as 100 g. These should be regarded as high-velocity missiles, because ini ally they travel at speed of over 3000 /sec, although they rapidly lose speed because of their volume, irregular shape, and aerodynamic instability and become low-velocity missiles at distances as near as 10 meters. The extent of ssue damage depends on the amount of energy expended by the missile at the point of ssue penetra on. As the projec le travels through the brain parenchyma, it is preceded by transient sonic wave (2μs) which appears to have minimal infl uence on surrounding ssue. The projec le itself, however, crushes the so brain ssue in its path, crea ng a permanent track of injury. This is in addi on to the secondary missiles such as bone and metal fragments created from the impact of projec le on the skull. Addi onally, a penetra ng injury is expected to be much more severe in case of a close range fi rearm injury as maximum amount of ini al kine c energy is transferred to the brain ssue. CLINICAL FINDINGS Most patients involved in civilian gunshot wounds to head are male (87%) in the third to fourth decade of life and are nearly equally divided between homicides (50%) and suicides (46%), with a small percentage being due to accidents (4%). Military vic ms of penetra ng brain injury tend to be younger. In civilian penetra ng brain injury an altered level of consciousness is the rule. Glasgow Coma Scale score of the pa ents is used to assess the level of consciousness.7 When sharp objects, low-velocity and spent bullets penetrate the brain, they may cause focal deficits; however, if they do not disrupt the neuronal circuitry in the brainstem tegmentum or ascending re cular ac va ng system, they may not cause a depressed level of consciousness. MANAGEMENT The Guidelines for the Management of Penetrating Brain Injury was adopted and published in The Journal of Trauma in August 2001, which has standardized both the medical and surgical management of these unique and challenging injuries.¹ The pre-hospital rescue, intuba on, oxygenation, ventilation, volume resuscitation, and medical management of pa ents with penetra ng brain injury must clearly be adopted from diff erent pre-hospital emergency department, cri cal care, and surgical guidelines. Immediately a er arrival of the pa ent in the emergency department, a primary survey and stabilization of the pa ent with regard to the airway, breathing, cervical spine, and circula on including external hemorrhage should be achieved. A er resuscita on, an inspec on of superfi cial wound should be done. The skin, especially the scalp, must be examined me culously for wounds as it may be covered by blood-ma ed hair. An entrance wound should be iden fi ed and its loca on recorded as well as any exit wounds when they exist. The superfi cial scalp should also be observed for powder burn, which would imply a close range fi rearm injury. Any cerebrospinal fl uid, bleeding, or brain parenchyma oozing from the wound should be noted, the size of the defi cit should also be documented. All orifi ces 113 AP Sharma must be checked for retained foreign bodies, the missile, teeth, and bone. A detailed neurological examina on should be performed, and post-resuscita ve Glasgow Coma Scale of the pa ents should be documented. A complete head to toe examina on is recommended as penetra ng brain injury pa ents may have mul ple organ injuries. A detailed medical history from family or friends and a chronology of the incidence from a witness is warranted. Ini al laboratory investigation must include a complete blood count, electrolytes, coagula on profi le, blood grouping and cross- matching and blood gas analysis. Once the ini al evalua on is done, the pa ent should have imaging studies. The u lity of various neuroimaging methods used in pa ents with penetra ng brain injury lies on the poten al management and prognostic implications of these modalities. Plain radiographs of the skull can be considerable value in identifying the cranial wounds, the location of missile and bone fragments, and the presence of intracranial air. Computed tomography scanning of the head is now the primary modality used in the neuroradiologic evalua on of patients with penetrating brain injury.2 Computed tomography, including three-dimensional reconstruc on of the head, defi nes the entry site and trajectory of the fragment into the brain, perforating, penetrating, or tangential terminal ballistics, and involvement of the paranasal sinuses, orbits, skull base, and mastoids. It defi nes the missile track, number of tracks and ricochet, whether the penetra on is across the midsagi al or midcoronal planes, and the presence or absence of intracranial hematomas such as acute epidural, subdural, intracerebral, or intraventricular hematomas. The extent of brain edema and ischemia and brainstem involvement is defi ned by computed tomography. If a vascular injury is suspected, then cerebral angiography is recommended. The sensi vity to diagnose vascular injury such as trauma c dissec on of the caro d or vertebral arteries with computed tomography angiography has been reported to be similar or even superior to that of magnetic resonance imaging angiography. In terms of other vascular pathology, the incidence of vasospasm in the se ng of blast-related penetra ng trauma c brain injury is high, approaching 50%. Thus, it is recommended that pa ents with acute penetra ng trauma c brain injury from explosives undergo regular noninvasive vascular assessment via transcranial Doppler, with follow-up invasive digital subtrac on angiography for defi ni ve diagnosis and endovascular interven on. Magne c Resonance Imaging is generally not recommended but can be useful in penetra ng brain injury caused by a wooden object. When stabiliza on and imaging are complete, decisions concerning further therapy o en take into account the pa ent’s neurologic status as determined by the Glasgow Coma Scale score. Poor survival and outcome are reported in pa ents with GCS scores between 3 and 5 points. Most neurosurgeons agree that a pa ent with a postresuscita on GCS score of 3 points with two dilated nonreac ve pupils but without a mass lesion on CT should not receive surgical interven on. It has long been known that bihemispheric and transventricular injuries have poor prognosis. SURGICAL MANAGEMENT The general guidelines of surgical treatment include: adequate debridement of devitalized ssue, removal of the mass lesions, removal of the accessible in-driven bone fragments and foreign bodies, adequate haemostasis, dural reconstruc on and complete closure of the scalp. The “Infec on in Neurosurgery” Working Party of Bri sh Society for Antimicrobial Therapy recommended the following regimen for penetra ng brain injury: intravenous co-amoxiclav 1.2g q 8h, or intravenous cefuroxime 1.5g, then 750mg q 8h, with intravenous metronidazole 500mg q 8h. It is recommended that this regimen should be started as soon as possible a er injury and con nued for 5 days postopera vely. Scalp lacera ons from missile head wounds are usually contaminated, have devitalized edges, and may be hard to repair. Treatment of small entrance wounds with local wound care and closure in pa ents whose scalp has not been devitalized and have no signifi cant intracranial pathological fi ndings on CT scan is not only adequate but recommended according to guidelines. When scalp is penetrated by a projec le, it is shredded, torn, or burned with devitalized edges of up to few millimeters, if feasible, it is strongly recommended that a plas c surgeon be consulted for primary closure of the skin over a torn dura, especially if the dural tear is at the base in the vicinity of the basal cisterns, near the air sinuses or mastoid air cells, to prevent CSF fi stulas. Once a pa ent has been classifi ed as a surgical candidate, a empts should be made to operate within 12 hours of injury to prevent infec on and resul ng abscesses.7 In the presence of signifi cant mass eff ect, debridement of necro c brain ssue along with safely accessible bone fragments is recommended. Brandvold and colleagues, Taha and associates, and more recently Amirjamshidi and coworkers, based on their experience in Israel, Lebanon, and Iran, respec vely, have reported on minimal debridement of missile head wounds in special circumstances.² Similarly, during arm-confl ict in Nepal, the penetra ng brain injuries were managed by less aggressive surgical debridement of devitalized brain ssue, removal of easily accessible metal and in-driven bone fragments with water ght closure of the dura mater at Birendra Hospital.¹0 It should be noted that any deeply seated bone fragments especially those in eloquent brain areas should not be retrieved because this has been shown to correlate with worse outcomes. This has marked a signifi cant trend since Vietnam era to proceed with a more conservative, minimally invasive approach toward cerebral debridement as this has been shown to improve outcomes and lower morbidity. As with bone fragments, only accessible missile fragments in non- 114 Journal of Lumbini Medical College eloquent brain should be retrieved although there has been some sugges on that removal of all missile fragments may decrease the risk of seizures. Intracranial haematomas with signifi cant mass eff ects should be evacuated. Although craniectomies around the entrance site of a projec le have been the favored technique in previous military confl icts, the present recommenda on is craniotomy and debridement of the skull with replacement of the bone to avoid the future need for cranioplasty. Recent war me explosive injuries from a transfrontal or transtemporal direc on may disrupt the anterior and lateral skull base. Such injuries are associated with signifi cant risk for CSF leaks and loss of anatomic con nuity between the anterior cranial fossa, orbits, maxilla, and infratemporal fossa. During the recent confl ict this has led to an aggressive strategy of early skull base repair with tanium mesh, local pericranium, fat, temporalis fascia, and muscle. COMPLICATIONS Pa ents who survive penetra ng craniocerebral injuries are at risk of experiencing mul ple complica ons, including persistence neurological defi cits, infec ons, epilepsy, CSF leak, cranial nerve defi cits, pseudoaneurysms, arteriovenous fi stulas, and hydrocephalus. The principal objec ves when trea ng pa ents with craniocerebral missile wounds are to lower morbidity and mortality and begin rehabilita on. Extensive studies have evaluated long-term survival and cogni ve, behavioral, and func onal outcome a er PBI, especially in war injuries sustained in World War II and Korean and Vietnam confl icts.5,13 For pa ents who survive a PBI, the size and loca on of the parenchymal injury may have a long-las ng eff ect on intelligence test scores. The focal motor defi cits with or without sensory defi cit can be hemiparesis, monoparesis, triparesis, paraparesis, pseudobulbar palsy, ataxia or spas c ataxia, quadriparesis, visual fi eld defi cit, cranial nerve defi cit, speech diffi culty etc. Depending on the entrance site, a persistent focal neurological defi cit is quite common in the survivors. The incidence of motor defi cits, visual fi eld cuts, and speech diffi cul es in the casual es from the Iran-Iraq War was 34.6%, 13.7%, and 6.1%, respec vely. INFECTIONS Since the early 1900s, various factors have been blamed for the high rate of infec on in war wounds like delays in evacuation of casualties, inadequate debridement and inability to close dura and skin water ght, lack of an bio cs, coma, extent of injuries, especially mul ple lobe and ventricle involvement, retained bone fragments and cerebrospinal fl uid fi stulas. Missile head wounds are contaminated wounds. The extent to which contamina ng organisms contribute to deep wound infections is debatable. Deep infec on remains the most important aspect of PBI that a neurosurgeon has to deal with. A follow-up revealed that in a popula on of 1221 pa ents with penetra ng cerebral trauma incurred in the Vietnam War, there was 3 percent incidence of brain abscess.4 This complica on usually occurred during the second or third week of injury. No rela onship existed between the presence of retained fragments and the development of either a seizure disorder or a subsequent CNS infec on. Overall, past military experiences have shown that mely evacua on and prophylac c ins tu on of broad-spectrum an bio cs followed by careful debridement of penetra ng craniocerebral wounds signifi cantly reduce the incidence of CNS infec on. CSF fi stulas should be treated most expedi ously to prevent the severe neurological sequelae of the CNS infec on. Dehiscence of a scalp fl ap incision is usually a result of infec on in an otherwise healthy young trauma vic m, but it can result from a failure in technical aspect of dural or scalp closure. POSTTRAUMATIC EPILEPSY The rela on of epilepsy to brain trauma has been recognized since the days of Hippocrates, but the pathogenesis of the pos rauma c epilepsy is s ll not clearly understood. Pa ents with focal neurological signs or large lesions has increased risk of epilepsy, and the site of the lesion may have been more important than size in determining in occurrence. Trauma c brain injury greatly increases the risk for a number of mental health problems and is one of the most common causes of medically intractable epilepsy in humans6. Several models of trauma c brain injury have been developed to inves gate the rela onship between trauma, seizures, and epilepsy-related changes in neural circuit func on. These studies have shown that the brain ini ates immediate neuronal and glial responses following an injury, usually leading to signifi cant cell loss in areas of the injured brain. Over me, long-term changes in the organiza on of neural circuits, par cularly in neocortex and hippocampus lead to an imbalance between excitatory and inhibitory neurotransmission and increased risk for spontaneous seizures. These include altera ons to inhibitory interneurons and forma on of new, excessive recurrent excitatory synap c connec vity.6 Penetra ng brain injury is one of the major risk factor for pos rauma c epilepsy. Studies of veterans from World War I, World War II, and the Korean, Vietnam, and Iran-Iraq wars indicate that between 34% and 50% vic ms of penetra ng brain injury become epileptic when monitored for 2 to 15 years. Follow-up studies indicated that the incidence of pos rauma c epilepsy in vic ms of PBI is higher than that in vic ms of closed head injury.5 The guidelines for “Management and prognosis of Penetra ng Brain Injury” recommend prophylac c an -seizure medica ons for the fi rst week a er PBI but not beyond that. CEREBROSPINAL FLUID LEAK 115 Cerebrospinal fl uid fi stulas in penetra ng craniocerebral wounds cons tute a serious complica on, which can increase morbidity and mortality. Cerebrospinal fl uid leak develops because of the dural tear by the missile along with a failure to adequately seal the defect by normal ssue healing processes.8 CSF leaks can present through the entry or exit sites of the projec le as well as through the ear or nose when the mastoid hair cells and open air sinuses have been violated, respec vely. The drainage of CSF from the site of opera ve debridement is o en caused by incomplete closure of the dural lacera on at the base of the skull or by a convexity dural suture line that is too ght. If the CSF leak develops several days later, in the absence of hydrocephalus or of mass eff ect and/or haematoma, one should assume and treat for wound infec on. When there is an injury of the frontal fossa fl oor, recurring CSF leaks usually result from an ini al incomplete explora on of the fossa fl oor. During the recent confl ict this has led to an aggressive strategy of early skull base repair with tanium mesh, local pericranium, fat, temporalis fascia, and muscle. This step is followed by more extensive skull base reconstruc on at level fi ve medical centers consis ng of rota onal or myocutaneous free fl aps in pa ents with persistent CSF leaks, progressive skull base deformity, and encephalocele. PSEUDOANEURYSMS AND ARTERIOVENOUS FISTULAS Vascular injuries are thought to be one of the main causes of fi eld mortality among pa ents with missile wounds to the head. Trauma c intracranial aneurysms are rela vely rare lesions most commonly associated with penetra ng wounds of the brain.9 Trauma c aneurysms are formed a er the par al or complete rupture of the arterial wall. The true incidence of trauma c neurovascular injury in pa ents with blast overpressure, closed brain injury, and PBI remains largely specula ve.¹² Although fi rst described in 1895 by Guibert, trauma c intracranial aneurysms have received li le a en on in the literature. The incidence of trauma c internal caro d artery aneurysm (TICA) a er such injuries ranges from 3% to 40%, depending on the ming of imaging studies. The ming of angiography a er a missile head wound may be an important factor in the detec ng aneurysms. In one report from the Iran-Iraq War, cerebral angiography an average of 17 days a er missile head wounds in 255 pa ents disclosed 8 aneurysms (3%). Jinkins and coworkers performed cerebral angiography within 24 hours of gunshot wounds to the head in 12 pa ents and found 3 internal caro d/vertebral and one combined aneurysm/arteriovenous fi stula (33%). Risk factors include orbitofaciocraniocerebral injuries, injuries near the pterion, and pa ents harboring intracranial haematomas. It is recommended that any pa ent with these risk factors undergo either CT angiography or conven onal angiography to rule out TICA. These injuries are treated endovascularly with either coiling or stent- assisted coiling, which resulted in preserva on of the parent artery. Despite endovascular treatment some pa ents need defi ni ve clip exclusion. Before the fi rst reported series of endovascular management of TICAs in 1993, treatment op ons available to the neurosurgeons were limited to balloon occlusion, balloon trapping, copper wire thrombosis, surgical liga on, and clipping or occlusion of the parent artery with or without bypass. Endovascular techniques are the methods of choice for the treatment of pa ents with caro d cavernous fi stulas. There is no general consensus regarding op mal management of internal caro d artery dissec on, but the choice among medical, endovascular, and surgical op ons may depend on the type of injury, the anatomic loca on, the mechanism of injury, coexis ng injuries, and comorbid condi ons. An coagulant therapy should be ini ated when a thrombus is detected. OUTCOME AND PROGNOSIS Penetrating brain injury, though less prevalent than closed head trauma, carries a worse prognosis. Many studies have a empted to associate various prognos c factors with outcome. The most important prognos c factor currently recognized is the Glasgow Coma Scale a er cardiopulmonary resuscita on. Tradi onally, the higher the GCS a er resuscita on, the be er the pa ent outcome. Extensive studies have evaluated long-term survival and cogni ve, behavioral, and func onal outcome a er PBI, especially in war injuries sustained in World War II and Korean and Vietnam confl icts. The Vietnam Head Injury Study has demonstrated that there are no truly silent area of the brain when it comes to penetra ng injuries. Regardless of how well pa ents seem to recover, very complex psychobehavioral and cogni ve func ons are adversely aff ected, and community adjustment is never perfect. For this reason, every approach to the treatment of penetra ng head injury must emphasize the preservation of brain tissue. A critical factor in early treatment decisions and long-term outcome a er penetra ng head injuries is the pa ent’s ini al level of consciousness.¹³ Low Glasgow Coma Scale is associated with an unfavorable outcome in both civilian and military PBI. GCS score of 3 with bilaterally fi xed and dilated pupils, and high ini al intracranial pressure have been correlated with worse outcomes in PBI pa ents. Increasing age, suicide a empt, coagulopathy, bihemispheric lesion, multilobar injuries, intraventricular haemorrhage, subarachnoid haemorrhage, transventricular injury, uncal hernia on, respiratory distress and hypotension all are associated with poor outcome. There is evidence that soldiers returning home from combat du es in Iraq and Afghanistan may suffer from poor general AP Sharma 116 Journal of Lumbini Medical College health and be more susceptible to cardiovascular complica ons, both of which can ul mately aff ect their job performance and produc vity. It is possible that mild trauma c brain injury (MTBI) under unusually stressful circumstances, such as blast injuries resul ng from the explosive eff ects of improvised explosive devices (IEDs), may aff ect the neuronal circuitry designed to monitor stressful conditions, such as the amygdala, lateral hypothalamus, and pituitary/adrenal axis. This eff ect may result in excessive amount of stressful hormones and icosanoids and deposi on of implicit memory of trauma that will result in pos rauma c stress disorder. A multiphasic research project is currently ongoing to inves gate pathogenesis and best ways to manage MTBI and PTSD. Research in this area is highly warranted as PBI pa ents s ll present a signifi cant challenge to practicing neurosurgeons worldwide. Patients with craniocerebral missile wounds who arrive at the hospital alive o en receive variable treatment despite low GCS scores and o en dismal prognoses, because there is a lack of consensus regarding appropriate treatment and predictable outcome in these pa ents. In par cular, wide varia ons exist in the amount of surgical debridement performed, the use of ICP monitoring, and the use of various medical therapies. CONCLUSION Gunshot wounds of the head are on increase. Penetra ng head injuries can be the result of numerous inten onal or uninten onal events, including missile wounds, stab wounds, and motor vehicle or occupa onal accidents (nails, screwdrivers). The pathological consequences of penetra ng head wounds depend on the circumstances of the injury, including the proper es of the weapon or missile, the energy of the impact, and the loca on and characteris cs of the intracranial trajectory. The clinical condi on of the pa ent depends mainly on the mechanism, anatomical loca on of the lesions, and associated injuries. The assessment of pa ents with penetra ng brain injuries should include rou ne laboratory tests, coagulation profile and imaging studies. Pa ents with severe penetra ng brain injuries should receive resuscita on according to Advanced Trauma Life Support Guidelines. The introduc on of Guidelines for the Management of Penetra ng Brain Injury has revolutionized the medical and surgical management of PBI during the last decade. There has been a paradigm shi toward a less aggressive debridement of deep seated fragments and a more aggressive an bio cs prophylaxis in an eff ort to improve outcomes.¹¹ Morbidity and mortality rates associated with penetrating brain injury remain unacceptably high. Considerable research con nues in the area of neurotrauma. Once the secondary mechanisms of injury are be er understood and the treatment modali es are studied in prospec ve randomized clinical trials, less varia on in management of penetra ng head injury is likely to occur. The medical community as a whole will become more successful in the treatment of these pa ents. REFERENCES 1. Benny Brandvold, M.D., Lion Levi, M.D., Moshe Feinsod, M.D. et al. Penetra ng craniocerebral injuries in the Israeli involvement in the Lebanese confl ict, 1982-1985. Analysis of a less aggressive surgical approach. J Neurosurg 1990; 72: 15-21. 2. Bizhan Aarabi B, M.D., F.R.C.S.C. Surgical outcome in 435 pa ents who sustained missile head wounds during the Iran-Iraq War. J Neurosurg 1990; 27: 692-695. 3. Espocito, Domenic P. MD, FACS; Walker, James B. MD. Contemporary Management of Penetra ng Brain Injury. Neurosurg Quarterly 2009; 19: 249-254. 4. Aarabi, Bizhan MD; Taghipour, Musa MD; Alibaii, Ehsanali MD. et al. Central nervous system infec ons a er military missile head wounds. J Neurosurg 1998; 42: 500-9. 5. Andres M. Salazar, MD; Bahman Jabbari, MD; Stephen C vance, MD. et al. Epilepsy a er penetra ng head injury. I. Clinical correlates: A report of the Vietnam Head Injury Study. J Neurol 1995; 35: 1406-14. 6. Robert F. Hunt. Jeff ery A. Boychuk. Bret N, Smith. Neural circuit mechanisms of pos rauma c epilepsy. Journal Fron ers in Cellular. Neuroscience 2013; 7: 89. 7. Syed Farak Kazim, Muhammad Shahzad Shamim Muhammad Zubair Tahir, Syed Ather Enam. et al. Management of penetrating brain injury. Journal of Emergencies, Trauma, and Shock. Jul-Sec; 4: PP 395- 402. 8. Arnold M. Meirowsky, MD; William F. Caveness, MD; James D. Dillon, MD. et al. Cerebrospinal fl uid fi stulas complica ng missile wounds of the brain. J Neurosurg 1981; 54: 44-8. 9. Sharma A.P, MD, FRCS(Ed). Nature and management of penetra ng craniocerebral missile injuries at Shree Birendra Hospital from November 2001 to November 2002. Med J Shree Birendra Hospital 2002; 5: 1-6. 10. Fuad Sami Haddad, MD, F.R.C.S.(C), F.A.C.S.; Georges F. Haddad, MD; and Jamal Taha, MD. Trauma c Intracranial Aneurysms Caused by Missiles: Their Presenta on and Management. J Neurosurg 1991; 28: 1-7. 11. Michael E. Carey, M.D. The treatment of war me brain wounds: Tradi onal versus minimal debridement. Surg Neurol 2003; 60: 112-9. 12. Bizhan Aaribi, M.D, F.R.C.S (C). Trauma c aneurysms of the brain due to high velocity missile head wounds. Journal of Neurosurgery 1998; 22: 1056-1063. 13. Michael L. Levy, M.D. Outcome prediction following penetra ng craniocerebral injury in a civilian popula on: Aggressive surgical management in patients with admission Glasgow Coma Scale scores of 6 to 15. Neurosurgery focus 1999; 8: Ar cle 2. 14. Schneiderman AI, Braver ER, Kang HK. 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