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The radiology of missile head wounds
Clin. Radiol. (1971) 22, 312-320
THE
RADIOLOGY
OF MISSILE
HEAD
WOUNDS
ADELOLA ADELOYE and E. LATUNDE ODEKU
Neurosurgery Unit, Department of Surgery, University of lbadan, Ibadan, Nigeria An account is given of the use of radiography in 164 Nigerians admitted to the University College Hospital, Ibadan, with missile head wounds. All of them had plain skull radiographs which assisted the classification of these wounds and showed appearances characteristic of some of these lesions. Cerebral angiography was performed on only 12 patients with positive results in 3. The indications and place of this procedure in the management of these wounds are discussed. It would appear that, as an investigation of choice, cerebral angiography is less valuable in missile head wounds than in civilian head injuries.
INTRODUCTION THE accounts of the radiology of large series of missile head wounds during the first and second world wars by Gamlen and Smith (1917) and McGrigor and Samuel (1945) were limited predominantly to the use of plain skull radiography, without the routine employment of cerebral angiography which Lohr in 1936 advocated for the investigation of head injuries. This paper describes our experience with the limited application of cerebral angiography in some patients, and the routine use of plain skull radiography in investigating 164 consecutive patients with missile head wounds seen in the Neurosurgery Unit of University College Hospital (U.C.H.), Ibadan, Nigeria between July 1967 and January 1969. We have omitted the details of the technique of radiography and have limited ourselves to its essential place in the classification of these wounds, the help it provided in their management and in unravelling some of the pathophysiological bases of these physical injuries. MATERIAL AND METHODS All of the patients except 12 civilians were Nigerian soldiers, who suffered head wounds due to bullets or metallic fragments from bomb or hand grenade explosions. After the conclusion of history taking and physical examination, all patients had initial plain skull radiographs (routine A-P, P-A and lateral views). Special views were also obtained as dictated by the nature of the injury under radiographic study. Associated areas of injury suspected of harbouring fractures or metallic foreign bodies were also studied radiographically.
Technical difficulties were often encountered during these procedures, due to lack of co-operation from the disorientated or restless patient; or the patient with a stiff, painful neck whose head could not be placed close to the film, and from the limitation of movement in those with multiple wounds. As most of these patients were victims from various battle fronts, these radiodiagnostic difficulties became aggravated when the wounded arrived at this hospital in an avalanche. In patients with intracranial missiles, up-to-date pre-operative series of skull radiographs were obtained within the hour before surgical operation when extraction of the missile was contemplated. Operative check radiographs were also employed in some cases to assist this procedure. All patients who had debridement of wound tracks and removal of fragments of bone or missiles had post-operative skull radiographs to evaluate the completeness of surgical debridement. In a few selected cases, cerebral angiography was performed under local anaesthesia by percutaneous injection technique, using 60 per cent solution of Urografin. RESULTS A. RESULTS OF PLAIN SKULL RADIOGRAPHS These have been useful in evolving a classification for the various head wounds as shown in Table 1. The radiographic features of the different categories of head wounds are summarised below. Other unusual findings are also illustrated. 1. Scalp Wounds Alone.--In 2 patients who had linear lacerations of the frontal scalp, a fine dust of 312
THE RADIOLOGY
OF M I S S I L E H E A D W O U N D S
313
TABLE 1 CLASSIFICATIONOF MISSILEHEAD WOUNDS Number of Patients
Type Scalp wounds alone .......... Missiles lodged in scalp . . . . . . Tangential skull wounds ........ Abrasive lesions ........ Comminuted fracture ...... Furrow fracture with: (a) Superficially placed bone fragments . . . . . . . . . . . . (b) In-driven bone fragments .. Penetrating Brain wounds . . . . . . . . Through-and-through brain wounds . . . . Miscellaneous . . . . . . . . . . . . Total
. . . . . . . . . . . .
21 6 64 4 5 5 50 69 9 1 164
metallic particles was radiologically demonstrated along the missile path. In some of the patients in this category, the missile may be lodged deep in the scalp as shown in Fig. 1, where an intact bullet was shown in the subgaleal space. At operation this missile was removed with ease and the wound debrided. An intact skull was encountered, without any stain by the missile. A burr hole was made in the intact calvarium under the wound, but no associated intracranial lesion was found. 2. Tangential Skull Wounds.--Three types of !skull injuries were encountered. The rarest and the least severe was the abrasive lesion in which the outer table of the skull was scored by the missile. More common, was the comminuted fracture in which the outer and inner tables of the skull were involved. The bone fragments stayed together in a mosaic pattern with no penetration into the intracranial cavity. The most severe and also the commonest lesion was the furrow fracture where the bone fragments have been driven intracranially. a. ABRASIVE SKULL L E S l O N . - - I n all t h o s e
FIG. 1 Skull radiograph showing intact bullet in subgaleal space in a scalp wound (arrow).
who
had this type of injury, routine skull radiographs were "grossly" negative. But unlike those with scalp wound alone, operative findings were different as illustrated in the case reported immediately below. Case 1.--History: 28-year-old Nigerian soldier. Wore steel helmet. Bomb explosion injury. N o loss o f consciousness. Post-traumatic headaches. Physical Examination: Fully conscious. Gutter type of scalp laceration in right parietal region. N o neurological deficit. Radiographic Examination: N o skull fracture seen. Operation: After debridement of right parietal wound, the exposed skull was found to be darkly stained by tiny metallic fragments. N o fractures were seen. Burr hole revealed an intact dura with a hue of blue; a very small collection of
FIG. 2 'Comminuted fracture' (arrows) in tangential skull wound.
314
CLINICAL
RADIOLOGY
subdural h a e m a t o m a was f o u n d a n d drained o n opening the dura.
b. COMM~NUT~D FRACTURE.--An example is shown in Fig. 2 in which the mosaic of bone fragments remained together with very little displacement. This may be missed on radiography and often it is only at operation that the full extent of the injury can be ascertained. c. FURROW FRACTURE.--Radiography was of indisputable value. The breach in the continuity of the calvarium was seen in all views in the plain radiographs. In some instances the bone fragment or fragments were displaced in a depressed fracture superficially over the dura (Fig. 3). More often, they were deeply positioned within the cranial cavity. In the latter position, the bone fragments were frequently driven in at right angles to the line of flight of the offending missiles, often with the bigger ones penetrating deeper than the smaller fragments (Fig. 4A). When more severe, linear fracture extensions ran from the anterior, posterior or both ends of the furrow in the skull, usually in the direction of flight of the missile (Fig. 4B). 3. Penetrating Brain Wounds.--The missile was always demonstrated intracranially on skull radiographs, in one whole piece (deformed or intact) or in fragments. In some of those with intact missiles, very little damage may be radiographically discernable at the point of entry. Where multiple metallic fragments have entered the intracranial cavity, like the bone fragments in tangential skull wounds, the
FIG. 3 Parietal 'furrow fracture' in tangential skull wound with superficially depressed bone fragments (arrow).
FIG. 4A FIG. 4a Fro. 4A--'Furrow fracture' with a cone of in-driven bone fragments (arrow). Note linear fracture extension (A) from the furrow in the skull. F~o. 4B--Lateral skull radiograph of same patient showing anterior (A) and posterior (B) linear fracture extensions.
THE RADIOLOGY
OF M I S S I L E H E A D
315
WOUNDS
bigger fragments as a rule penetrated deeper (Fig. 5). 4. Through and Through Brain Wounds.--In this category of wounds the missile entered the head at one point, traversed the cranial cavity and emerged at another point. The skull defect at the point of entry was merely a puncture fracture close to which were in-driven fragments of bone (Fig. 6). At the exit, where brain destruction was more extensive, there was usually a comminuted and more extensive fracture, some fragments of which were lifted from the rest of the skull (Fig. 6). Associated Wounds.--These, when severe and life-threatening, took priority over the definitive surgical treatment of the head wounds. Limb injuries, most of which were associated with fractures, were the commonest encountered.
Other Unusual Findings: SPONTANEOUS
FIG. 5 Penetrating head wound. Note tiny metallic fragments close to entry wound (c), linear fracture extension in direction of missile path (o), and the bigger fragments penetrating deeper (E).
MOVEMENT
OF ]NTRACRANIAL
MISSILE.--This rare phenomenon was encountered once in the series. Fig. 7A showed the position of the bullet which lodged intracranially following a penetrating injury. Two days later, with the patient on the operating table for wound debridement and extraction of the bullet, repeated radiographic study showed the bullet in a new position, having undergone spontaneous 'version' (Fig. 7B). TRAUMATIC PNEUMOCEPHALUS.--The ventricular
system was spontaneously outlined by air in 2 patients with wounds in which the ventricle was
FIG. 6 Through and through brain wound. Note in-driven bone fragments (F) close to entry wound (arrow), and out-driven plates of bone (G) near exit wound (thick arrow).
316
CLINICAL
RADIOLOGY
FIG. 7A FtG. 7B FIG. 7A.--Intact intracranial bullet. F~G. 7B.--Two days later. Note new position of bullet which has turned round with patient intubated for operation.
FIG. 8A FIG. 8B Antero-posterior and lateral skull-radiographs showing air in the lateral ventricles.
pierced. Both proved fatal. One whose radiographs are shown (Fig. 8) had a penetrating brain wound. B. RESULTS OF CEREBRAL ANGIOGRAPHY In this series, carotid angiography was attempted on 14 patients all with head wounds in which the dura was penetrated by missiles or bone fragments
which had come to rest deeply within the cranium. The procedure was abandoned in 2 patients due to lack of co-operation, leaving 12 patients for analysis. The indications for angiography were as follows: 1. Unexplained severe or progressing localised/ unilateral neurological deficits several days after wounding. 2. Suspected vascular occlusion.
THE RADIOLOGY OF MISSILE HEAD WOUNDS
317
3. Suspected arterio-venous fistula. 4. Suspicion of superficial (extra/subdural) blood clot. Group 1: Unexplained Severe or Progressing Neurological Defieits.--These were patients with apparently mild tangential injuries whose neurological deficits remained unusually severe or started to progress in some instances, long after wounding. All had a dense hemiplegia. One of them whose case history is given below also developed epilepsy 4 months after his injury.
caused vascular occlusion. These were all negative, however.
Case 2.--History: 35-year-old Nigerian soldier shot on the left side of the head. Wore only jungle hat. Scalp laceration was sutured in the medical reception station close to war front without adequate wound debridement. Persistent weakness of the right limbs. Four months later developed Jacksonian fits involving the right side of the body. Physical examination: Febrile, dysphasic man. Infected, partially healed left parietal parasagittal tangential scalp wound. Right facial weakness of upper motor neurone type. Dense right hemiplegia. Skull:Radiographs: In-driven bone fragments. Left carotid angiogram: No mass lesions or vascular shifts seen. Operation: Debridement of wound with removal of in-driven bone fragments and a small pocket of intracerebral pus. Subsequent course: He has been seizure-free for nearly a year; however, the improvement in his hemiplegia has been slow.
of the intracranial cavity along the w o u n d track of a penetrating missile wound, there was a striking rarity o f subdural h a e m a t o m a large enough to present clinically. The only such case encountered is described below.
All of the patients with hemiplegia had operative debridement involving the removal o f bone fragments buried in a lot o f glial tissue. Group 2: Suspected Vascular Oeelusion.--There was only one positive result in the 5 patients in this group who were investigated by angiography (Case 3). The patient had no neurological deficit, but the anatomical location of the lodged missile caused us to suspect injury to the internal carotid artery.
Case 3.--History: 18-year-old Nigerian soldier shot in the head. Occasional occipital headache. Physical Examination (4 weeks later): Fully conscious, dull witted boy. Blind left eye, otherwise no abnormal findings. Skull radiograph: Intact bullet in right middle cranial fossa, close to the sella turcica and the anatomical course of the right internal carotid artery (intracavernous position) (Fig. 9A). Right common carotM angiography: Filling of only the external carotid circulation. Occlusion of the right internal carotid artery (Fig. 9B). Left common earotid angiography: Spontaneous filling of the intracranial parts of both internal carotid arteries (Fig. 9c). This chance finding increased our index o f suspicion, and led us to investigate 4 other patients with intracranial missiles which by the nature o f their course and resting position could have
Group 3: Suspected Traumatic Arterio-venous Fistula.---The only patient in this group was a y o u n g soldier with penetrating w o u n d o f the right orbit w h o presented with a pulsating mass filling the injured orbit 4 days after wounding. N o bruit was elicited on auscultation of the mass. Carotid angiographs demonstrated an intracerebral haemat o m a in the right temporo-frontal region (Fig. 10).
Group 4: Suspected Superficial Blood C l o t . Although h a e m a t o m a was encountered at all levels
Case 4.--History: 27-year-old right-handed Nigerian soldier. Hit on the head by multiple metallic fragments from bomb explosion on February 10, 1969. No loss of consciousness. Scalp wounds were debrided at the Military Hospital. Fifteen days after wounding, he was noticed to be sleeping excessively and, when awake, wandered about aimlessly. A subdural haematoma was suspected. Physical examination: Lethargic man unable to sustain interest in his surroundings. Well healed wounds in left parieto-occipital scalp. Dysphasic. Pulse 56/min, BP 110/80 mm Hg. Skull radiograph showed multiple metallic fragments in the left parietal region. Carotid angiograms showed shift of the left anterior and middle cerebral arteries to the opposite side. A lentiform avascular area was seen in the left parietal area, suggesting a subdural haematoma (Fig. 11). Operation: Through left parietal and frontal burr holes, a unilateral chronic subdural haematoma was drained. Subsequent History: The patient had remained very well since then. DISCUSSION G a m l e m and Smith (1917) during the First World W a r made an extensive study of the interrelation o f radiography and surgery o f gunshot wounds o f the head, and M c G r i g o r and Samuel (1945) used radiography to classify the various missile head wounds which they encountered during the Second World War. The latter authors recognised 'injuries caused by glancing and by direct missiles' which correspond respectively to our tangential skull w o u n d s and penetrating brain injuries. In our current series, we have, in addition, highlighted the place of carotid angiography in the management o f these wounds. R a d i o g r a p h y alone has its use and limitation in the classification and handling o f missile head wounds since adequate evaluation depends chiefly on clinical assessment o f the w o u n d and the operative findings. F o r instance, in the 'abrasive'
318
CLINICAL
FIG. 9A
RADIOLOGY
[FIG. 9B FIG. 9A--Intact bullet in cavernous sinus (arrow). FIG. 9B--Right common carotid angiography. Filling of external carotid circulation only. (Bullet \ ) . FIG. 9c--Spontaneous filling of the intracranial parts of both internal carotid arteries in left common carotid angiography.
FIG. 9c
type of tangential skull injury in our series, no lesion was detectable on radiography, whereas at operation, a shallow grooving or faint crack of the outer table was usually encountered. In the 'comminuted fracture' type of tangential skull wound also, especially when the temporal region was involved, there may be no radiological sign of wounding, only to find at operation a mosaic of undisplaced comminuted bone fragments. We have had no radiographic example comparable to that of Gamlen and Smith (1917) to illustrate the zig-zag course taken by intracranial missile before coming to rest. But we are convinced that an intracranial missile may move spontaneously inside the injured brain or within an encysted area
or natural compartment in it. Gamlen and Smith viewed this phenomenon with concern arguing that 'unless there is exact reduplication of the position of the head in the radiographs, the altered position of the missile is difficult to prove'. In our patient (Fig. 7) the bullet has turned round in a manner reminiscent of the spontaneous version described in one similar case by Jefferson (1918). Even more spectacular movements have been described in missiles lodged in or near the ventricle (Small and Turner, 1947; Taverner and Phillips, 1947) or in the subdural space (Cairns et al., 1947). Since the days of Lohr (1936)-the use of cerebral angiography in investigating head trauma has found increasing application outside the continent
THE RADIOLOGY
OF M I S S I L E H E A D W O U N D S
FxG. 10 Displacement of anterior cerebral artery to the left. Intracerebral haematoma in right orbito-cranial penetrating wound.
319
of Europe. It is now used routinely in parts of England, Australasia, and America (Campbell and Campbell, 1961; Hancock, 1961; Vanderfield, 1961; Leslie et al., 1962; Thomson, 1963a) and only recently Murphy (1968) in Uganda found that 'the commonest indication for the investigation was that of head injury'. While the place of cerebral angiography in daily head trauma due to road traffic accidents and the like has been amply proven, the same cannot be said confidently at present in missile head wounds since the latter injuries are seen less frequently in peace-time civilian life. Progressive neurological deterioration of a patient with head injury in civilian practice is often due to a mass lesion. Cerebral angiography not only helps to demonstrate these lesions, but also in planning the surgical approach. In missile head wounds, intracranial haematoma is often of smaller extent and usually located along or near the missile path, hence rarely needing angiography for its identification. In the few cases in our series with persisting or progressing neurological deficit, primary damage or destruction of brain tissue rather than intracranial haematoma had been largely responsible. The only exception was the one example of subdural haematoma large enough to present clinically (Case 4). The striking rarity of this lesion in missile head injuries is probably the result of adequate decompression consequent on bone and dural defects inflicted by those missiles. Where the puncture fracture is so small as in Case 4,
FIG. I1A FIG. l i b FIG. llA and liB--Arterial and venous phases of carotid angiography (antero-posterior view), showing chronic subdural haematonla following penetrating bomb explosion head wound. Note intracranial metallic fragments and displacements of anterior and middle cerebral vessels to the opposite side.
320
CLINICAL RADIOLOGY
this spontaneous decompression may be lacking, thus facilitating the formation of a subdural haematoma. There have been a few reports of post-traumatic occlusion of intracranial arteries in civilian experience (Sedzimir, 1955, Thomson, 1963b). In war injuries, the incidence must be lower still, since 'cases with penetrating wounds into the head do not often come to angiography' (Thomson, 1963a). There may also be instances of symptomless vascular occlusion as in the solitary example in our series (Case 3). Positive findings were encountered in only 3 of our 12 patients who had cerebral angiography. This is a low yield when compared with the 70 per cent of positive findings in civilian head injuries recorded by Hancock (1961) and Thomson (1963b). The place of cerebral angiography in missile head wounds is better appreciated if premised on the 'usefulness' of the information it provides. In our patients with neurological deficits for example, there were no haematoma or abscesses found angiographically, a 'useful' finding in the understanding of the patho-physiology of these lesions, which were probably due to primary brain damage. As to the future, angiography in missile head injury may find some use in evaluating those patients with retained intracranial missiles, since these objects may move to positions when they may compromise intracranial vessels with or without symptoms. A complication of missile head wounds in need of more study is dural sinus thrombosis
(Holmes and Sargent, 1915). The intelligent employment of angiography may further our understanding of this lesion (Adeloye and Odeku, 1971). Aeknowledgement.--We are indebted to the members of
our Medical Illustration Unit for their assistance in the preparation of the figures. REFERENCES ADELOYE,A. & ODE~ZU,E. L. Journal of Neurosurgery, 34,155. CAIRNS, l-L, CALVERT, C. A., DANIEL, P. & NORTHCROFT, G. B. (1947). British Journal of Surgery, War Supplement, No. 1, 198. CAMPBELL, J. A. & CAMPBELL,R. L. (1961). Journal of the American Medical Association, 175, 761. GAMLEN, I-L E. & SMITH, S. (1917). British Journal of Surgery, 5, 17. HANCOCK, D. O. (1961). Lancet, 2, 745. HOLMES, G. & SARGENT,P. (1915). British Medical Journal, 2, 493. JEFFERSON, G. (1918). British Journal of Surgery, 5, 422. LESLIE, E. V., SMITH, B. H., ZOLL, J. G. (1962). Radiology, 78, 930. LOHR, W. (1936). Zentralblattfiir Chirurgie, 18, 2466. McGRIGOR, D. B. & SAMUEL,E. (1945). British Journal of Radiology, 18, 221. MURPHY, N. B. (1968). East African Medical Journal, 45, 47. SEDZIMIR, C. B. (1955). Journal of Neurology, Neurosurgery and Psychiatry, 18, 293. SMALL, J. M. • TURNER, E. A. (1947). British Journal of Surgery, War Supplement, No. 1, 62. TAVERNER, D. & PHILLIPS, G. (1947). British Journal of Surgery, War Supplement, No. 1,262. TROMSON, J. L. G. (1963a). Clinical Radiology, 14, 339. THOMSON, J. L. G. (1963b). British Journal of Radiology, 36, 840. VANDERFIELD, G. (1961). Australian and New Zealand Journal of Surgery, 30, 292.
THE
RADIOLOGY
OF MISSILE
HEAD
WOUNDS
ADELOLA ADELOYE and E. LATUNDE ODEKU
Neurosurgery Unit, Department of Surgery, University of lbadan, Ibadan, Nigeria An account is given of the use of radiography in 164 Nigerians admitted to the University College Hospital, Ibadan, with missile head wounds. All of them had plain skull radiographs which assisted the classification of these wounds and showed appearances characteristic of some of these lesions. Cerebral angiography was performed on only 12 patients with positive results in 3. The indications and place of this procedure in the management of these wounds are discussed. It would appear that, as an investigation of choice, cerebral angiography is less valuable in missile head wounds than in civilian head injuries.
INTRODUCTION THE accounts of the radiology of large series of missile head wounds during the first and second world wars by Gamlen and Smith (1917) and McGrigor and Samuel (1945) were limited predominantly to the use of plain skull radiography, without the routine employment of cerebral angiography which Lohr in 1936 advocated for the investigation of head injuries. This paper describes our experience with the limited application of cerebral angiography in some patients, and the routine use of plain skull radiography in investigating 164 consecutive patients with missile head wounds seen in the Neurosurgery Unit of University College Hospital (U.C.H.), Ibadan, Nigeria between July 1967 and January 1969. We have omitted the details of the technique of radiography and have limited ourselves to its essential place in the classification of these wounds, the help it provided in their management and in unravelling some of the pathophysiological bases of these physical injuries. MATERIAL AND METHODS All of the patients except 12 civilians were Nigerian soldiers, who suffered head wounds due to bullets or metallic fragments from bomb or hand grenade explosions. After the conclusion of history taking and physical examination, all patients had initial plain skull radiographs (routine A-P, P-A and lateral views). Special views were also obtained as dictated by the nature of the injury under radiographic study. Associated areas of injury suspected of harbouring fractures or metallic foreign bodies were also studied radiographically.
Technical difficulties were often encountered during these procedures, due to lack of co-operation from the disorientated or restless patient; or the patient with a stiff, painful neck whose head could not be placed close to the film, and from the limitation of movement in those with multiple wounds. As most of these patients were victims from various battle fronts, these radiodiagnostic difficulties became aggravated when the wounded arrived at this hospital in an avalanche. In patients with intracranial missiles, up-to-date pre-operative series of skull radiographs were obtained within the hour before surgical operation when extraction of the missile was contemplated. Operative check radiographs were also employed in some cases to assist this procedure. All patients who had debridement of wound tracks and removal of fragments of bone or missiles had post-operative skull radiographs to evaluate the completeness of surgical debridement. In a few selected cases, cerebral angiography was performed under local anaesthesia by percutaneous injection technique, using 60 per cent solution of Urografin. RESULTS A. RESULTS OF PLAIN SKULL RADIOGRAPHS These have been useful in evolving a classification for the various head wounds as shown in Table 1. The radiographic features of the different categories of head wounds are summarised below. Other unusual findings are also illustrated. 1. Scalp Wounds Alone.--In 2 patients who had linear lacerations of the frontal scalp, a fine dust of 312
THE RADIOLOGY
OF M I S S I L E H E A D W O U N D S
313
TABLE 1 CLASSIFICATIONOF MISSILEHEAD WOUNDS Number of Patients
Type Scalp wounds alone .......... Missiles lodged in scalp . . . . . . Tangential skull wounds ........ Abrasive lesions ........ Comminuted fracture ...... Furrow fracture with: (a) Superficially placed bone fragments . . . . . . . . . . . . (b) In-driven bone fragments .. Penetrating Brain wounds . . . . . . . . Through-and-through brain wounds . . . . Miscellaneous . . . . . . . . . . . . Total
. . . . . . . . . . . .
21 6 64 4 5 5 50 69 9 1 164
metallic particles was radiologically demonstrated along the missile path. In some of the patients in this category, the missile may be lodged deep in the scalp as shown in Fig. 1, where an intact bullet was shown in the subgaleal space. At operation this missile was removed with ease and the wound debrided. An intact skull was encountered, without any stain by the missile. A burr hole was made in the intact calvarium under the wound, but no associated intracranial lesion was found. 2. Tangential Skull Wounds.--Three types of !skull injuries were encountered. The rarest and the least severe was the abrasive lesion in which the outer table of the skull was scored by the missile. More common, was the comminuted fracture in which the outer and inner tables of the skull were involved. The bone fragments stayed together in a mosaic pattern with no penetration into the intracranial cavity. The most severe and also the commonest lesion was the furrow fracture where the bone fragments have been driven intracranially. a. ABRASIVE SKULL L E S l O N . - - I n all t h o s e
FIG. 1 Skull radiograph showing intact bullet in subgaleal space in a scalp wound (arrow).
who
had this type of injury, routine skull radiographs were "grossly" negative. But unlike those with scalp wound alone, operative findings were different as illustrated in the case reported immediately below. Case 1.--History: 28-year-old Nigerian soldier. Wore steel helmet. Bomb explosion injury. N o loss o f consciousness. Post-traumatic headaches. Physical Examination: Fully conscious. Gutter type of scalp laceration in right parietal region. N o neurological deficit. Radiographic Examination: N o skull fracture seen. Operation: After debridement of right parietal wound, the exposed skull was found to be darkly stained by tiny metallic fragments. N o fractures were seen. Burr hole revealed an intact dura with a hue of blue; a very small collection of
FIG. 2 'Comminuted fracture' (arrows) in tangential skull wound.
314
CLINICAL
RADIOLOGY
subdural h a e m a t o m a was f o u n d a n d drained o n opening the dura.
b. COMM~NUT~D FRACTURE.--An example is shown in Fig. 2 in which the mosaic of bone fragments remained together with very little displacement. This may be missed on radiography and often it is only at operation that the full extent of the injury can be ascertained. c. FURROW FRACTURE.--Radiography was of indisputable value. The breach in the continuity of the calvarium was seen in all views in the plain radiographs. In some instances the bone fragment or fragments were displaced in a depressed fracture superficially over the dura (Fig. 3). More often, they were deeply positioned within the cranial cavity. In the latter position, the bone fragments were frequently driven in at right angles to the line of flight of the offending missiles, often with the bigger ones penetrating deeper than the smaller fragments (Fig. 4A). When more severe, linear fracture extensions ran from the anterior, posterior or both ends of the furrow in the skull, usually in the direction of flight of the missile (Fig. 4B). 3. Penetrating Brain Wounds.--The missile was always demonstrated intracranially on skull radiographs, in one whole piece (deformed or intact) or in fragments. In some of those with intact missiles, very little damage may be radiographically discernable at the point of entry. Where multiple metallic fragments have entered the intracranial cavity, like the bone fragments in tangential skull wounds, the
FIG. 3 Parietal 'furrow fracture' in tangential skull wound with superficially depressed bone fragments (arrow).
FIG. 4A FIG. 4a Fro. 4A--'Furrow fracture' with a cone of in-driven bone fragments (arrow). Note linear fracture extension (A) from the furrow in the skull. F~o. 4B--Lateral skull radiograph of same patient showing anterior (A) and posterior (B) linear fracture extensions.
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OF M I S S I L E H E A D
315
WOUNDS
bigger fragments as a rule penetrated deeper (Fig. 5). 4. Through and Through Brain Wounds.--In this category of wounds the missile entered the head at one point, traversed the cranial cavity and emerged at another point. The skull defect at the point of entry was merely a puncture fracture close to which were in-driven fragments of bone (Fig. 6). At the exit, where brain destruction was more extensive, there was usually a comminuted and more extensive fracture, some fragments of which were lifted from the rest of the skull (Fig. 6). Associated Wounds.--These, when severe and life-threatening, took priority over the definitive surgical treatment of the head wounds. Limb injuries, most of which were associated with fractures, were the commonest encountered.
Other Unusual Findings: SPONTANEOUS
FIG. 5 Penetrating head wound. Note tiny metallic fragments close to entry wound (c), linear fracture extension in direction of missile path (o), and the bigger fragments penetrating deeper (E).
MOVEMENT
OF ]NTRACRANIAL
MISSILE.--This rare phenomenon was encountered once in the series. Fig. 7A showed the position of the bullet which lodged intracranially following a penetrating injury. Two days later, with the patient on the operating table for wound debridement and extraction of the bullet, repeated radiographic study showed the bullet in a new position, having undergone spontaneous 'version' (Fig. 7B). TRAUMATIC PNEUMOCEPHALUS.--The ventricular
system was spontaneously outlined by air in 2 patients with wounds in which the ventricle was
FIG. 6 Through and through brain wound. Note in-driven bone fragments (F) close to entry wound (arrow), and out-driven plates of bone (G) near exit wound (thick arrow).
316
CLINICAL
RADIOLOGY
FIG. 7A FtG. 7B FIG. 7A.--Intact intracranial bullet. F~G. 7B.--Two days later. Note new position of bullet which has turned round with patient intubated for operation.
FIG. 8A FIG. 8B Antero-posterior and lateral skull-radiographs showing air in the lateral ventricles.
pierced. Both proved fatal. One whose radiographs are shown (Fig. 8) had a penetrating brain wound. B. RESULTS OF CEREBRAL ANGIOGRAPHY In this series, carotid angiography was attempted on 14 patients all with head wounds in which the dura was penetrated by missiles or bone fragments
which had come to rest deeply within the cranium. The procedure was abandoned in 2 patients due to lack of co-operation, leaving 12 patients for analysis. The indications for angiography were as follows: 1. Unexplained severe or progressing localised/ unilateral neurological deficits several days after wounding. 2. Suspected vascular occlusion.
THE RADIOLOGY OF MISSILE HEAD WOUNDS
317
3. Suspected arterio-venous fistula. 4. Suspicion of superficial (extra/subdural) blood clot. Group 1: Unexplained Severe or Progressing Neurological Defieits.--These were patients with apparently mild tangential injuries whose neurological deficits remained unusually severe or started to progress in some instances, long after wounding. All had a dense hemiplegia. One of them whose case history is given below also developed epilepsy 4 months after his injury.
caused vascular occlusion. These were all negative, however.
Case 2.--History: 35-year-old Nigerian soldier shot on the left side of the head. Wore only jungle hat. Scalp laceration was sutured in the medical reception station close to war front without adequate wound debridement. Persistent weakness of the right limbs. Four months later developed Jacksonian fits involving the right side of the body. Physical examination: Febrile, dysphasic man. Infected, partially healed left parietal parasagittal tangential scalp wound. Right facial weakness of upper motor neurone type. Dense right hemiplegia. Skull:Radiographs: In-driven bone fragments. Left carotid angiogram: No mass lesions or vascular shifts seen. Operation: Debridement of wound with removal of in-driven bone fragments and a small pocket of intracerebral pus. Subsequent course: He has been seizure-free for nearly a year; however, the improvement in his hemiplegia has been slow.
of the intracranial cavity along the w o u n d track of a penetrating missile wound, there was a striking rarity o f subdural h a e m a t o m a large enough to present clinically. The only such case encountered is described below.
All of the patients with hemiplegia had operative debridement involving the removal o f bone fragments buried in a lot o f glial tissue. Group 2: Suspected Vascular Oeelusion.--There was only one positive result in the 5 patients in this group who were investigated by angiography (Case 3). The patient had no neurological deficit, but the anatomical location of the lodged missile caused us to suspect injury to the internal carotid artery.
Case 3.--History: 18-year-old Nigerian soldier shot in the head. Occasional occipital headache. Physical Examination (4 weeks later): Fully conscious, dull witted boy. Blind left eye, otherwise no abnormal findings. Skull radiograph: Intact bullet in right middle cranial fossa, close to the sella turcica and the anatomical course of the right internal carotid artery (intracavernous position) (Fig. 9A). Right common carotM angiography: Filling of only the external carotid circulation. Occlusion of the right internal carotid artery (Fig. 9B). Left common earotid angiography: Spontaneous filling of the intracranial parts of both internal carotid arteries (Fig. 9c). This chance finding increased our index o f suspicion, and led us to investigate 4 other patients with intracranial missiles which by the nature o f their course and resting position could have
Group 3: Suspected Traumatic Arterio-venous Fistula.---The only patient in this group was a y o u n g soldier with penetrating w o u n d o f the right orbit w h o presented with a pulsating mass filling the injured orbit 4 days after wounding. N o bruit was elicited on auscultation of the mass. Carotid angiographs demonstrated an intracerebral haemat o m a in the right temporo-frontal region (Fig. 10).
Group 4: Suspected Superficial Blood C l o t . Although h a e m a t o m a was encountered at all levels
Case 4.--History: 27-year-old right-handed Nigerian soldier. Hit on the head by multiple metallic fragments from bomb explosion on February 10, 1969. No loss of consciousness. Scalp wounds were debrided at the Military Hospital. Fifteen days after wounding, he was noticed to be sleeping excessively and, when awake, wandered about aimlessly. A subdural haematoma was suspected. Physical examination: Lethargic man unable to sustain interest in his surroundings. Well healed wounds in left parieto-occipital scalp. Dysphasic. Pulse 56/min, BP 110/80 mm Hg. Skull radiograph showed multiple metallic fragments in the left parietal region. Carotid angiograms showed shift of the left anterior and middle cerebral arteries to the opposite side. A lentiform avascular area was seen in the left parietal area, suggesting a subdural haematoma (Fig. 11). Operation: Through left parietal and frontal burr holes, a unilateral chronic subdural haematoma was drained. Subsequent History: The patient had remained very well since then. DISCUSSION G a m l e m and Smith (1917) during the First World W a r made an extensive study of the interrelation o f radiography and surgery o f gunshot wounds o f the head, and M c G r i g o r and Samuel (1945) used radiography to classify the various missile head wounds which they encountered during the Second World War. The latter authors recognised 'injuries caused by glancing and by direct missiles' which correspond respectively to our tangential skull w o u n d s and penetrating brain injuries. In our current series, we have, in addition, highlighted the place of carotid angiography in the management o f these wounds. R a d i o g r a p h y alone has its use and limitation in the classification and handling o f missile head wounds since adequate evaluation depends chiefly on clinical assessment o f the w o u n d and the operative findings. F o r instance, in the 'abrasive'
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CLINICAL
FIG. 9A
RADIOLOGY
[FIG. 9B FIG. 9A--Intact bullet in cavernous sinus (arrow). FIG. 9B--Right common carotid angiography. Filling of external carotid circulation only. (Bullet \ ) . FIG. 9c--Spontaneous filling of the intracranial parts of both internal carotid arteries in left common carotid angiography.
FIG. 9c
type of tangential skull injury in our series, no lesion was detectable on radiography, whereas at operation, a shallow grooving or faint crack of the outer table was usually encountered. In the 'comminuted fracture' type of tangential skull wound also, especially when the temporal region was involved, there may be no radiological sign of wounding, only to find at operation a mosaic of undisplaced comminuted bone fragments. We have had no radiographic example comparable to that of Gamlen and Smith (1917) to illustrate the zig-zag course taken by intracranial missile before coming to rest. But we are convinced that an intracranial missile may move spontaneously inside the injured brain or within an encysted area
or natural compartment in it. Gamlen and Smith viewed this phenomenon with concern arguing that 'unless there is exact reduplication of the position of the head in the radiographs, the altered position of the missile is difficult to prove'. In our patient (Fig. 7) the bullet has turned round in a manner reminiscent of the spontaneous version described in one similar case by Jefferson (1918). Even more spectacular movements have been described in missiles lodged in or near the ventricle (Small and Turner, 1947; Taverner and Phillips, 1947) or in the subdural space (Cairns et al., 1947). Since the days of Lohr (1936)-the use of cerebral angiography in investigating head trauma has found increasing application outside the continent
THE RADIOLOGY
OF M I S S I L E H E A D W O U N D S
FxG. 10 Displacement of anterior cerebral artery to the left. Intracerebral haematoma in right orbito-cranial penetrating wound.
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of Europe. It is now used routinely in parts of England, Australasia, and America (Campbell and Campbell, 1961; Hancock, 1961; Vanderfield, 1961; Leslie et al., 1962; Thomson, 1963a) and only recently Murphy (1968) in Uganda found that 'the commonest indication for the investigation was that of head injury'. While the place of cerebral angiography in daily head trauma due to road traffic accidents and the like has been amply proven, the same cannot be said confidently at present in missile head wounds since the latter injuries are seen less frequently in peace-time civilian life. Progressive neurological deterioration of a patient with head injury in civilian practice is often due to a mass lesion. Cerebral angiography not only helps to demonstrate these lesions, but also in planning the surgical approach. In missile head wounds, intracranial haematoma is often of smaller extent and usually located along or near the missile path, hence rarely needing angiography for its identification. In the few cases in our series with persisting or progressing neurological deficit, primary damage or destruction of brain tissue rather than intracranial haematoma had been largely responsible. The only exception was the one example of subdural haematoma large enough to present clinically (Case 4). The striking rarity of this lesion in missile head injuries is probably the result of adequate decompression consequent on bone and dural defects inflicted by those missiles. Where the puncture fracture is so small as in Case 4,
FIG. I1A FIG. l i b FIG. llA and liB--Arterial and venous phases of carotid angiography (antero-posterior view), showing chronic subdural haematonla following penetrating bomb explosion head wound. Note intracranial metallic fragments and displacements of anterior and middle cerebral vessels to the opposite side.
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CLINICAL RADIOLOGY
this spontaneous decompression may be lacking, thus facilitating the formation of a subdural haematoma. There have been a few reports of post-traumatic occlusion of intracranial arteries in civilian experience (Sedzimir, 1955, Thomson, 1963b). In war injuries, the incidence must be lower still, since 'cases with penetrating wounds into the head do not often come to angiography' (Thomson, 1963a). There may also be instances of symptomless vascular occlusion as in the solitary example in our series (Case 3). Positive findings were encountered in only 3 of our 12 patients who had cerebral angiography. This is a low yield when compared with the 70 per cent of positive findings in civilian head injuries recorded by Hancock (1961) and Thomson (1963b). The place of cerebral angiography in missile head wounds is better appreciated if premised on the 'usefulness' of the information it provides. In our patients with neurological deficits for example, there were no haematoma or abscesses found angiographically, a 'useful' finding in the understanding of the patho-physiology of these lesions, which were probably due to primary brain damage. As to the future, angiography in missile head injury may find some use in evaluating those patients with retained intracranial missiles, since these objects may move to positions when they may compromise intracranial vessels with or without symptoms. A complication of missile head wounds in need of more study is dural sinus thrombosis
(Holmes and Sargent, 1915). The intelligent employment of angiography may further our understanding of this lesion (Adeloye and Odeku, 1971). Aeknowledgement.--We are indebted to the members of
our Medical Illustration Unit for their assistance in the preparation of the figures. REFERENCES ADELOYE,A. & ODE~ZU,E. L. Journal of Neurosurgery, 34,155. CAIRNS, l-L, CALVERT, C. A., DANIEL, P. & NORTHCROFT, G. B. (1947). British Journal of Surgery, War Supplement, No. 1, 198. CAMPBELL, J. A. & CAMPBELL,R. L. (1961). Journal of the American Medical Association, 175, 761. GAMLEN, I-L E. & SMITH, S. (1917). British Journal of Surgery, 5, 17. HANCOCK, D. O. (1961). Lancet, 2, 745. HOLMES, G. & SARGENT,P. (1915). British Medical Journal, 2, 493. JEFFERSON, G. (1918). British Journal of Surgery, 5, 422. LESLIE, E. V., SMITH, B. H., ZOLL, J. G. (1962). Radiology, 78, 930. LOHR, W. (1936). Zentralblattfiir Chirurgie, 18, 2466. McGRIGOR, D. B. & SAMUEL,E. (1945). British Journal of Radiology, 18, 221. MURPHY, N. B. (1968). East African Medical Journal, 45, 47. SEDZIMIR, C. B. (1955). Journal of Neurology, Neurosurgery and Psychiatry, 18, 293. SMALL, J. M. • TURNER, E. A. (1947). British Journal of Surgery, War Supplement, No. 1, 62. TAVERNER, D. & PHILLIPS, G. (1947). British Journal of Surgery, War Supplement, No. 1,262. TROMSON, J. L. G. (1963a). Clinical Radiology, 14, 339. THOMSON, J. L. G. (1963b). British Journal of Radiology, 36, 840. VANDERFIELD, G. (1961). Australian and New Zealand Journal of Surgery, 30, 292.