Pneumorachis of the cervical spine with associated pneumocephalus and subcutaneous emphysema.

Pneumorachis, the presence of free intraspinal air, is an exceptional radiological finding. We present a case that sustained injury following an assault and was diagnosed to have diffuse pneumocephalus, pneumorachis and extensive surgical emphysema of the head and neck region secondary to the fracture of the cribriform plate of ethmoid bone. To the best of our knowledge pneumorachis due to fracture of the cribriform plate of ethmoid bone has not been reported before, in the English language literature.

INTRODUCTION

Pneumocephalus is relatively common but associated pneumorachis is a rare entity despite the intracranial compartment and spinal canal remaining in communication with each other.12 Gordon and Hardman (1977) were the first to describe the phenomenon of intraspinal air.3 Pneumorachis can also be secondary to pneumothorax, pneumomediastinum, pneumocephalus, subcutaneous emphysema, bowel perforation or as iatrogenic event of postdiskectomy.2 Very few cases of pneumorachis associated with head injury are reported in literature [Table 1].1–10 In a majority of the cases, pneumorachis is not associated with neurological symptoms. No definitive guidelines for its treatment exist because of its rareness and diverse etiologies. We present a rare case of pneumorachis of the cervical canal associated with pneumocephalus and surgical emphysema secondary to fracture of cribriform plate of ethmoid bone that made uneventful recovery with conservative management.

Table 1

Published case reports of pneumorachis

CASE REPORT

A 24-year-old male presented to the accident and emergency department with history of assault and having sustained sharp cut injuries in the neck over the anterolateral aspect extending till the nape and occiput. There was presence of three lacerations (two over the anterolateral aspect of the neck and one over the lateral aspect of the neck extending till the nape) with active bleeding from the same region. The margins of the lacerations were well defined and minimal contamination was present. After sustaining the assault, the patient fell down and struck his head against bricks over the ground. The patient had a history of profuse bleeding during transportation. There was no apparent associated injury. On examination, the patient was unconscious (Glasgow coma score 12/15). The pulse rate was 100 per minute and the blood pressure was 100/58 mmHg.

An intravenous line was secured and fluid resuscitation was started. Lacerations were repaired under all aseptic precautions. The patient was shifted with cervical collar for urgent noncontrast computed tomography (NCCT) scan of the head with screening of cervical spine [Figure 1]. NCCT revealed fracture of the cribriform plate of ethmoid bone with evidence of moderate pneumocephalus in the subarachnoid spaces in the basifrontal, suprasellar cistern region. There was presence of pneumorachis in relation to the posterior arch of atlas and the body of the third cervical vertebra, and there was no evidence of fracture or subluxation in the cervical spine [Figures 2a]. Extensive surgical emphysema was also noted in the lateral and posterior aspects of the cervical region [Figure 1b]. Magnetic resonance imaging (MRI) and contrast angiogram of cervical spine, NCCT chest and abdomen revealed normal study. The patient was started on injectable analgesics and antibiotics. He was also kept on 100% oxygen for 6 h to facilitate resolution of pneumocephalus and pneumorachis. There was no neurological deficit. A repeat NCCT of the head and cervical spine after 72 h revealed complete resolution of pneumocephalus and pneumorachis [Figure 2b]. The patient was discharged 4 days after the admission. There was no incidence of delayed cerebrospinal fluid rhinorrhoea and he was completely asymptomatic at the 1 year follow up.

Figure 1

(a) Noncontrast CT scan of the head showing diffuse pneumocephalus in the brain parenchyma and moderate pneumocephalus in the subarachnoid spaces in the basifrontal region. (b) Axial view; noncontrast computed tomography cervical spine showing pneumorachis at the craniovertebral junction and C3 level (arrow head). Surgical emphysema may also be noted in the lateral aspect of the neck

Figure 2

(a) Sagittal view; noncontrast computed tomography cervical spine showing presence of pneumorachis (solid arrow) in relation to the posterior arch of atlas and the body of the third cervical vertebra without an evidence of fracture or subluxation. (b) Sagittal view; noncontrast computed tomography cervical spine and head showing resolution of pneumorachis and pneumocephalus after 72 hours

Written, informed consent was obtained from the patient authorizing treatment, radiological examination and photographic documentation. He also consented that data concerning the case would be submitted for publication.

DISCUSSION

Pneumorachis is an exceptional but eminent radiological finding, accompanied by different etiologies and possible pathways of air entry into the spinal canal. The phenomenon of intraspinal air has been described with various terms such as intraspinal pneumocoele, spinal epidural and subarachnoid pneumatosis, aerorachia, pnemosaccus or traumatic pneumomyelogram.1–59, The term pneumorrhachis was first coined by Newbold et al. (1987).4 It is sparsely described in the literature and is usually asymptomatic and underdiagnosed entity with associated injuries. With the advent of advanced imaging techniques like acute phase multidetector computed tomography, such cases are now detected more easily.

Various causes of pneumorachis are now known, which include trauma (pneumothorax, pneumomediastinum, pneumocephalus, subcutaneous emphysema, bowel perforation), various respiratory conditions causing high intrathoracic pressure and barotraumas, surgical or diagnostic procedures, malignancy, infections with gas-forming organisms or even idiopathic.12 In our patient a fracture of the cribriform plate of ethmoid bone might have lead to escape of air in various planes giving rise to subcutaneous emphysema apart from pneumocephalus and pneumorachis. Goh et al. (2005) paid special attention to differentiate between air in the subarachnoid space versus air in the epidural space, as both the conditions have different clinical implications. Epidural emphysema, by itself, is usually innocuous, whereas subarachnoid pneumorachis is a marker of severe injury and is commonly associated with pnemocephalus.11 A traumatic subarachnoid pneumorachis is developed secondary to pneumocephalus. The occurrence of either a fracture of an air-containing cavity on the cranium or an open skull fracture with a dural tear allows free communication of air into the subarachnoid space, resulting in pneumocephalus.12 The air can then travel to the cervical subarachnoid space or even more distal as the intracranial compartment and spinal canal are in communication. This communication was valiantly shown by Dandy (1919) with the use of air as a negative contrast medium into the lumbar subarachnoid space for diagnostic pneumoencephalogram.13

Because pneumorachis is usually asymptomatic, it is primarily a radiographic and not a clinical diagnosis.1 CT scan is considered as the diagnostic modality of choice for a reliable and prompt detection of pneumorachis. Nevertheless, it may be difficult to differentiate epidural emphysema and subarachnoid pneumorachis on CT.11 Even MRI or contrast CT may be required for differentiation. Traumatic pneumorachis is a marker of severe injury, and its presence should alarm the treating physician to carry out diagnostic workup for the associated injury.

Owing to its rareness and diverse etiologies, no definitive guidelines for its treatment exist and it largely based upon individual case reports [Table 1]. Cervical pneumorachis with head injury has not been reported to be associated with neurological deficit. Yousaf et al. reported a case of pneumorachis with associated radicular symptoms and treated him successfully with cervical collar and supplemental oxygen.9 The presence of traumatic subarachnoid pneumorachis implies an open injury with an accompanying 25% risk of meningitis.14 Injectable antibiotics may be instituted to prevent this potential complication. Association of significant or persistent cerebrospinal fluid leakage have been treated with neurosurgical patch repair or temporary lumbar drainage.478 If general anesthesia is required in such patients, the attending anesthetist should not use inhalational nitrous oxide as it causes an increase in the intracranial pressure after diffusing into the air-filled spaces.15 Few workers have used supplemental oxygen therapy to facilitate air absorption.29

The present report intends to increase awareness about pneumorachis among orthopedic surgeons. It is usually asymptomatic and self-limiting, but its presence should alert the attending trauma physician to carry out diagnostic workup for associated injury and treat the underlying cause.