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Retained intracranial splinters : a follow up study in survivors of low intensity military conflicts.
Correspondence Address:
With improvements in the ballistic physics, patient evacuation, imaging, neurosurgical management and intensive care facilities, there has been overall improvement in the survival of patients with missile injuries of the brain. Patients with retained intracranial fragments have been followed up and the sequelae of such fragments were analysed. We present our observations in 43 such patients who had survived low velocity missile injuries of the brain during military conflicts and had retained intracranial fragments. Over a follow up period of 2 to 7 years, suppurative sequelae (brain abscess, recurrent meningitis) were seen in 6 patients, two of these progressing to formation of brain abscess. Three patients developed hydrocephalus and one seizures. Patients with orbitocranial or faciocranial wound of entry had a higher incidence of suppurative complications (3 out of 4), while those with skull vault entry had a lower incidence of such sequelae (7 out of 30). Nine patients were lost to follow up. Other determinants of suppurative complications were postoperative CSF leak and intraventricular lodgement of the fragment.
The literature on missile injuries of the brain sustained in war is more extensive than the one dealing with such injuries sustained during peacetime. While high velocity missile injuries (HVMIs) are almost invariably fatal, majority of the survivors would have sustained low velocity missile (LVM) injuries. Source of LVMs is generally a shrapnel from a grenade, rocket or improvised explosive device (IED) etc. With rapid evacuation of such patients to neurosurgical centres, availability of computed tomography (CT), improved understanding of missile ballistics and better neurosurgical techniques and postoperative care, there has been overall improvement in the survival of these patients. This has also resulted in more survivors with retained intracranial splinters, who have been followed up over a period of years and the sequelae and outcome of retained splinters have been analysed. We present our observations in 43 such patients with retained intracranial splinters. Relevant literature is briefly reviewed.
A total of 18 patients with low velocity missile injuries (LVMIs) of the brain were seen among the Indian Army personnel during Sri Lanka operations in 1987-1989, and 92 patients were treated in Jammu and Kashmir from 1990-1996.[1] The sources of missiles were IEDs, grenades, rockets and rifle bullets. There were 28 orbitocranial and two frontoorbitomaxillary injuries. All the injuries were supratentorial. Assessment and Initial Management : Patients were evacuated to the nearest Base Hospital after the injury, within half an hour to more than 24 hours. Triage was carried out and priority allotted. After resuscitation, patients with brain injuries were neurologically evaluated; this examination formed the baseline for all subsequent neurological evaluation. Head was shaved and open wounds were dressed. Intravenous mannitol, frusemide and antibiotics were administered. All patients had skull radiographs taken. CT brain could be done in 23 patients before surgery.
Initial Surgery : Ninety patients underwent surgery. Eight patients died in the hospital prior to surgery, and nine patients with small puncture wounds and no neurological deficit, were not operated upon and followed up. Craniectomy was done at the site of entry/exit wounds. Debridement was done till normal looking brain was seen and cavity did not collapse. Metallic splinters were removed only if they were seen during the course of debridement. Retained Intracranial Splinters : Forty three survivors had retained intracranial splinters. Out of these, in the postoperative period, two patients with orbitocranial injury and ten patients with skull vault injury had CSF leak from the wound for a period of 3-12 days. The distribution of these patients is as given in [Table I]. These patients have been followed up for over a period varying between one year to ten years. Nine patients (two non-operated cases with puncture wounds and seven operated cases) were lost to follow up. The sequelae of retained splinters in the remaining 34 is as given in [Table II]. It is observed that three out of four patients with orbitocranial injury and 7 out of 30 cases with skull vault injury had suppurative sequelae. Recurrent meningitis was followed by hydrocephalus, which required ventriculoperitoneal shunting. In one of these patients with puncture wound and no neurological deficit, there was intraventricular lodgement of the splinter [Figure - 1]. Brain abscess was seen in two cases who earlier had recurrent bouts of meningitis [Figure - 2]. Abscesses were excised in both the cases together with the retained missile fragments, which was seen adherent to/embedded in the abscess wall. No abscess was seen in skull vault group. One of these, however, developed temporal lobe seizures requiring antiepileptic medication. These patients are being followed up and have remained stable. No sequelae have been noted in the remaining 23 patients with retained intracranial splinters on follow up [Figure - 3] and [Figure - 4].
In the past, military neurosurgeons believed it was imperative to remove all intracranial bone and metal pieces in a patient with splinter injury of the brain. Reoperation was advocated if retained fragments were evident after initial debridement.[2],[3] One of the primary histological concerns with a less aggressive approach has been the fear of intracerebral abscess formation.4 Martin and Campbell5 recorded a parenchymatous infection rate of 16% based on their World War II experience. They believed that infection was 10 times more likely to occur in the presence of retained bone fragments than in their absence. Nevertheless, the complication rate of secondary procedures is high and consists of increased neurological deficit, enhancement of cerebral oedema, infection and deaths. Others[6],[7],[8] have advocated a more conservative approach. Brandvold et al[6] reported 83 patients with splinter injury to brain with retained metal or bone fragments. At follow up, there were no suppurative sequelae. The low incidence of brain abscess and inconsistent presence of retained fragments in patients presenting with abscess has been confirmed by the Vietnam head injury study (VHIS).[9] In an analysis of 127 war inflicted missile injuries sustained in North- Eastern Croatia, Vrankovic et al,[10] reported an incidence of retained fragments in 76.8% of the patients, with intracranial infection rate of 10% in these patients. In a recently concluded exhaustive study on splinter injuries to brain during Iran-Iraq war,11 it has been brought out that retained bone and metal fragments were less important factors in CNS infections after military head wounds. The factors consistently leading to suppurative complications are:- a) Facio-orbital wound of entry, traversing the air filled sinuses :The intracranial contents are in communication with potentially infected mucus secreting spaces, with higher risk of intracranial sepsis. b) CSF leak : Persistent CSF leak, especially more than 24 hours old, is fraught with danger of meningitis and ventriculitis. c) Intraventricular lodgement of the missile fragment. Although the possible epileptogenic effects of retained metal fragments - especially copper - have been mentioned,[12] there is no definite indication for pursuing metallic fragments beyond those that are readily accessible. The single exception is metallic migrating fragment. Intraparenchymal bullets generally do not migrate; intraventricular fragments are the ones that do and these should be removed by endoscopic manoeuvers or by stereotaxy.[13]
With improvement in evacuation of patients with missile injury to the brain, better understanding of the pathology, improved imaging modalities, surgical facilities and postoperative care, there will be more patients surviving the initial injury. Missile fragments need not be specially searched for during debridement so as to avoid aggravation of neurological damage. The fragments should be removed only if they are visible. Retained intracranial fragments do not, predispose the patient to suppurative complications. On the other hand, other factors like postoperative brain swelling and CSF leak, orbitocranial trajectory and intraventricular lodgement are associated with increased incidence of such complications. Patients with retained intracranial missile fragments should be on regular follow up so that such complications are recognized and treated as they occur.
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