A rare case of intraspinal penetrating rubber bullet injury causing thecal sac tear: Surgical extraction with neurological recovery

INTRODUCTION

Penetrating spinal trauma is usually caused by metal projectiles, which can be readily identified on radiographs and computed tomography (CT) because they are radiopaque.¹ Rubber bullets, which are often used for controlling crowds, are, however, non-metallic and radiolucent², making diagnosis of spinal injury difficult. Even though they were intended as “less-lethal” munitions, rubber bullets can cause severe injury when discharged at close proximity, including deep tissue penetration and neurological impairment.³ Magnetic resonance imaging (MRI) provides better soft-tissue detail and has become the modality of choice for the detection of radiolucent foreign bodies, assessment of dural integrity, and surgical planning.³ We report a unique case of lumbar intraspinal rubber bullet injury with thecal sac disruption and neurological deficit, effectively treated with surgical decompression, removal, and duraplasty.

CASE REPORT

A 26-year-old man with bilateral lower limb weakness (motor power 3/5) and sensory loss below the L3 dermatome presented after a rubber bullet hit to the lumbar region at close range. Local inspection disclosed a puncture entry wound in the left paraspinal region without an exit wound [Figure 1]. Initial radiographs and CT of the lumbar spine did not disclose any foreign body or osseous trauma [Figure 2]. The CT image did not provide a clear picture of the cord status, which underscores the limitations of traditional imaging to find non-metallic missiles.⁴ MRI of the lumbar spine showed a well-circumscribed hypointense lesion traversing the L3 lamina and encroaching upon the thecal sac at the level of L3–L4 with resultant dural tear and cerebrospinal fluid (CSF) leak [Figure 3].

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Figure 1:

Clinical image showing a puncture entry wound over the lumbar region without an exit site.

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Figure 2:

Preoperative- lumbar spine (a) X-ray and (b) CT lumbar spine demonstrating absence of foreign body, illustrating the radiolucent nature of the rubber bullet. CT: Computed tomography.

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Figure 3:

MRI lumbar spine (a and b) (sagittal and axial sequences) revealing a hypointense intradural lesion (marked with the arrow) at the L3–L4 level compressing the thecal sac. MRI: Magnetic resonance imaging

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The patient was taken for an L3–L4 laminectomy within 24 hours of injury after the work-up to excise the intradural foreign body. Intraoperative inspection found a 3.5 × 1.2 cm rubber bullet fragment intradurally impacted, resulting in compression of the thecal sac and disruption of the dura with the underlying cord contusion [Figure 4a]. The bullet was removed microsurgically [Figure 4 b], and the dural defect was closed with a synthetic graft and fibrin sealant [Figure 4c]. The rationale behind using the synthetic graft was the damage to the underlying fascia caused by the bullet impact and the contaminated wound, and to aid in a more predictable watertight closure.^5,6 The removed projectile is demonstrated in [Figure 5]. Postoperative course was incident-free with full neurological recovery (5/5) on day 7 and satisfactory healing of the wound.

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Figure 4:

Intra-operative image showing (a) rubber bullet fragment lodged intradurally compressing the thecal sac, (b) microsurgical extraction of the bullet fragment, (c) post-extraction surgical field showing decompressed thecal sac and duraplasty

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Figure 5:

Extracted rubber bullet fragment measuring approximately 3.5 × 1.2 cm.

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DISCUSSION

Most penetrating spinal injuries are due to metallic gunshot injuries, which are easily diagnosed on X-ray and CT imaging.⁷ Rubber bullets, on the other hand, made of composite elastomeric material, are not radiopaque and frequently go undetected with these modalities.⁸ This case illustrates the diagnostic challenge and highlights the utility of MRI in detecting non-metallic foreign bodies.⁹ MRI is critical in obtaining information regarding neural compression, dural integrity, and CSF leak, which directly aids surgical management planning.¹⁰ Rubber projectiles, unlike metallic bullets, are MRI-compatible, thus avoiding the risks of migration and heat injury.^9,10 Early surgery is recommended if there is evidence of neurological deficit or CSF leak.⁵ In this case, urgent decompression, removal, and duraplasty resulted in an optimal outcome. This case emphasizes that so-called 'less-lethal' weapons can produce devastating spinal injuries when fired at close range. It also aligns with prior reports emphasizing the value of MRI in identifying radiolucent projectiles and guiding surgical planning. Timely decompression and dural repair remain crucial for neurological recovery, as summarized in the table given below [Table 1].^11-16

So with the literature review and our case it would be safe to say the following :

• Non-metallic rubber bullets may result in severe penetrating spinal injuries, which are occult on X-ray or CT.

• MRI is indicated to identify radiolucent foreign bodies and to evaluate neural and dural injury.

• Early surgical decompression and duraplasty are critical to prevent neurological deterioration.

• Clinical practice should take into account the extent of injuries inflicted by 'less-lethal' weapons.

CONCLUSION

Rubber bullet-caused penetrating spinal injuries are not very common but represent an important diagnostic and therapeutic problem because they appear radiolucent. MRI assumes a crucial role in the detection of such non-metallic foreign bodies and dural and neural trauma associated with them. Early surgical treatment consisting of decompression, removal, and duraplasty provides the optimal results. The physician should have a high suspicion for severe injury from 'less-lethal' weapons and should utilize multimodal imaging for early treatment. Early recognition and MRI-based surgical management can prevent permanent deficits in non-metallic radiolucent projectiles like rubber or wooden objects, causing spinal injuries that are equally harmful as metallic bullets commonly encountered.