Letter to Editor
Transorbital cerebellar airgun pellet injury
Figure 3: T2 weighted image in sagittal plane (a) and axial plane (b) showing occipital encephalocele with bony defect and scalp mass isointense with the cortical grey matter and multiple flow voids.
syndrome. The cerebellum within those cephaloceles is usually dysplastic and gliotic.[5] Plexiform NF, hallmark of NF-I are found in 30-40% of all patients with NF-I. They usually arise along the axis of a major nerve, are unencapsulated and infiltrate producing fusiform appearance. They commonly occur along orbital division of V nerve, but other areas are not exempt often associated with sphenoidal dysplasias, they are hypervascular and enhance intensely on post contrast MR. Our patient had an occipital encephalocele with dysplastic cerebellum. However, the presence of additional parietal bony defects a finding well described in NF-I and the associated plexiform neurofibroma of the adjacent scalp suggests that the bony defect in our case could be due to the mesodermal dysplasia of NF-I. The peculiarity of this case of NF-I lies not in the presence of plexiform NF, bony dysplasia or cephalocele, findings well documented in literature, but in their unusual occipital location a site hitherto reported till now only in one case so far to the best of our knowledge.
N. K. Bodhey, A. K. Gupta
Sir, Air guns, although considered to be toys, can cause injuries ranging from trivial to grievous. The potential of airguns for causing injury is underestimated. Recent concerns have been raised about the safety of them as toys.[1] A rare case involving a young boy, who was accidentally hit by an air gun pellet during play, is described. Although there are many previous reports of intracranial air-gun pellet injuries, transorbital cerebellar injury due to air-gun pellets has not been reported previously in Medline. We present a 15-year-old boy was hit accidentally by an air gun pellet during play. There was a small enterance wound in the lower right orbital fold and he and his family were primarily concerned about his eyes on admission. Neurological examination including visual acuity and eye movements were intact. The Xray and CT scan showed the presence of an air-gun pellet to the posterior fossa [Figure 1a, b, c]. Other CT scan images showed that the air gun pellet travelled through the orbit without penetrating the globe. It passed into the middle cranial fossa and lodged in the posterior fossa. Considering the trajectory of the pellet, the patient underwent cerebral angiography which was normal. A suboccipital craniectomy in the prone position was performed and the air-gun pellet was removed as confirmed by a CT scan (Figure 1d). During the operation, we used only anteroposterior and lateral X-rays for localization of the pellet. Cefazolin and then oral cephalexin were adminstered to the patient for two weeks. No antiepileptics were administered to the patient. The patient had an uneventful postoperative course. Air gun pellets are low velocity missiles that cannot pass easily through the adult skull bone. The possible points of entrance into the skull are through the eye, temporal and frontal bones and A
B
Departments of Imaging Sciences and Interventional Radiology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India. E-mail:
[email protected]
References 1. 2. 3.
4. 5.
D
Smirniotopoulos JG & Murphy FM. The phakomatoses. AJNR 1992;13:725–46. Shu HH, Mirowitz SA, Wippold FJ 2nd . Neurofibromatosis: MR imaging findings involving the head and spine. AJR Am J Roentgenol 1993;160:159–64. Renshaw A, Borsetti M, Nelson RJ, Orlando A. Massive plexiform neurofibroma with associated meningo–encephalocoele and occipital bone defect presenting as a cervical mass. Br J Plast Surg 2003;56:514–7. Naidich TP, Altman NR, Brafman BH, McLone DG, Zimmerman RA. Cephaloceles and related malformations. AJNR Am J Neuroradiol 1992;13:655–90. Diebler C, Dulac O. Cephaloceles: Clinical & Neuroradiological appearance. Neuroradiology 1983;25:199–216.
Accepted on 06-01-2006
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C
Figure 1: A. Anteroposterior skull X-ray illustrating the air gun pellet, B. Lateral skull view, C. Axial CT scan showing that the pellet has been lodged in the posterior fossa, D. Postoperative axial CT scan.
Neurology India | March 2006 | Vol 54 | Issue 1
Letter to Editor
nose.[1] It is usually assumed that low velocity missiles in contrary to high velocity missiles[2] do not penetrate the brain very far and lodge near the entry points .[3] In the present case the right eye has been the point of entrance. As in the majority of previous reports, the enterance wound was small. In one reported case the pellet entering through the orbit lodged in the occipital lobe.[3] In other previous reports the pellet could not penetrate farther than the cavernous sinus when entering through the orbit, probably due to resistance in the trajectory of the pellet.[1, 4] Although the air-gun pellet could be removed rather easily in this case, use of ultraound and other intraoperative imaging modalities could be of great help in localization of the pellet in similar cases. There is no evidence-based recommendation concerning antibiotics in such cases, but its administration seems rational. Since the air-gun pellet was lodged in the cerebellum, no antiepileptics were administered. This case again shows the potential of air-guns for causing serious injuries. This and previous reports show that air-gun pellets can penetrate the brain far enough to injure any intracranial elements in their trajectory.[1,3,4] Actions are needed to make airguns safer and reduce their availability to children and teenagers.
supplied by the branches of the vertebral, intercostals, lumbar, middle sacral or subclavian arteries and rarely by the branches of the internal iliac artery. SDAVFs represent at least 35% of all spinal vascular malformations in large series.[1] A 50-year-old male presented to the neurosurgical department with burning sensation of foot bilaterally with episodes of urinary retention and progressive weakness in right lower limb for the last one month. There was mild spasticity of both lower limbs, right more than left, with grade 5/5 power. However, the day before surgery his power in the lower limbs worsened suddenly to grade 4/5 in proximal and grade 3/5 in the distal muscle group. Deep tendon reflexes in the lower limbs were exaggerated, right more than left. The anal and cremasteric reflexes were absent. MRI of the dorso-lumbar spine [Figure 1] was highly suggestive of a dural AVF with abnormal tortuous intradural flow voids in T2 WI seen in the thoracolumbar region. There were hyperintensities within the spinal cord at this level. Spinal angiogram [Figures 2-
Behzad Eftekhar, Mohammad Ghodsi, Ebrahim Ketabchi, Babak Esmaeeli Department of Neurosurgery, Sina Hospital,
Tehran University, Iran.
E-mail:
[email protected]
References 1. 2. 3. 4.
Holland P, O’Brien DF, May PL. Should airguns be banned? Br J Neurosurg 2004;18:124–9. Singh P. Missile injuries of the brain results of less aggressive surgery. Neurol India 2003;51:215–9 Amirjamshidi A, Abbassioun K, Roosbeh H. Air–gun pellet injuries to the head and neck. Surg Neurol 1997;47:331–8. Gilmour DF, Ramaesh K, Fleck BW. Trans–orbital intra–cranial air gun injury. Eur J Ophthalmol 2003;13:320–3.
Figure 1: MRI lumbar region T2 W sagittal showing dilated tortuous epidural vein, cord changes
Accepted on 18-11-2005
Lumbar spinal dural arteriovenous fistula with a supply from a lumbar multimetameric arterial system Sir, Spinal dural arterio-venous fistulas (AVF) are abnormal arteriovenous communications on the surface of the dura. They are Neurology India | March 2006 | Vol 54 | Issue 1
Figure 2: Selective right L3 lumbar angiogram oblique views. ‘Unsubtracted and DSA images’. Right lumbar metameric origin of L3 and L4 at L3 level from abdominal aorta. Dural fistula from L4 radicular branch
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