Case Report

Spinal epidural air after severe pelvic and abdominal trauma

Abstract

Air in the lumbar Spinal canal after trauma is uncommon. However, it can be observed in a number of pathologic settings including tumor, infection, degenerative disk disease, and in patients who have undergone therapeutic and Diagnostic procedures. Intraspinal gas is usually asymptomatic. We report a case of a Motorcycle accident resulting in a complex open pelvic and multiple long bone fractures. Air was discovered within the spinal canal between levels L3 and L5 on a computed tomographic scan. This case provides further evidence that intraspinal air may remain without symptoms and that possible resultant symptoms and the air can disappear spontaneously.

The presence of gas or air in the spinal canal is also called pneumorrhachis or pneumatorrhachis. This phenomenon is extremely rare, occasionally occurring in a number of pathologic settings including tumor, degenerative disk disease or spinal infection, extreme exercise, extreme expiratory effort against resistance, in patients who have undergone therapeutic or Diagnostic procedures such as lumbar puncture or peridural or epidural injection, and rarely in trauma [1-3]. The air can be located in the epidural, subdural, or subarachnoid space [4]. The origin of the air in the spinal canal in the trauma setting is often elusive and can be a diagnostic challenge. We present a case with a complex pelvic and multiple Intraabdominal injuries resulting in air within the lumbar spinal canal.

A 28-year-old male was admitted to our level I trauma center after a motorcycle accident on the highway. At the scene, he was fully orientated with a Glasgow Coma Scale score of 15. The vital signs were as follows: blood pressure of 97/65 mm Hg, heart rate of 112 beats per minute, and respiratory rate of 21 breaths per minute. Subsequently, the patient became hemodynamically unstable and required intubation and mechanical ventilation. On examination in the hospital, multiple contusion marks in the upper abdomen and superficial lacerations in the left lower and upper abdomen were identified. A prominent, large, venously bleeding, deep laceration wound was evident in the left

inguina. Primary diagnosis revealed a right-sided pneu- mothorax, a complex open pelvic fracture, fractures of the left femur and left distal humerus, and a luxated right shoulder. Result of Abdominal ultrasonography revealed a small quantity of free liquid within the peritoneal cavity. Conspic- uous laboratory results were a hemoglobin level of 7.9 g/dL and platelet count of 115 x 10⁹/L. The primary management included application of a right-sided thorax drainage and a pelvic C-clamp. A computed tomographic (CT) scan revealed a small fluid collection within the abdomen but not in the Douglas. In addition to the complex open pelvic fracture, a rupture of the liver, spleen, and right kidney and a tear of the urethra were also observed. The cerebral CT scan revealed no Pathologic findings. Closer examination of the lumbar CT scan also showed left-sided spinal epidural air between levels L3 and L5 (Fig. 1). Subsequently, the patient was taken into theater. An external fixator was applied to the left femur after open reduction and internal fixation of the open pelvic fracture. A fasciotomy of the left thigh was performed to prevent compartment syndrome, and the large inguinal laceration was debrided. The patient remained hemodynami- cally stable and did not require surgical treatment of his intraabdominal injuries. A total of 23 U of erythrocyte concentrate, 4 U of thrombocyte concentrate, 12 g of fibrinogen, 2000 IU of Beriplex (CSL Behring GmbH, Marburg, Germany), 1 500 000 IU aprotinin, 12 mg Novo Seven (Novo Nordisk Inc, Princeton, NJ), and 3250 IU Fibrogamin (CSL Behring GmbH) were administered. The patient was difficult to wean from the ventilator and required 6 days of mechanical ventilation. Twenty-one days post-

Fig. 1 A, initial CT scan showing left-sided spinal epidural air. B, Follow-up CT scan showing complete resorption of spinal epidural air.

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operatively, he was transferred from the intensive care unit to the orthopedic ward and showed an uneventful recovery and was discharged to a rehabilitation facility 45 days after initial admission.

Pneumorrhachis was first described by Newbold et al [5]. The affected patient was involved in a motor vehicle accident, and subsequently, gas embedding was discovered within the cervical spinal canal on the conventional x-ray. A further examination with a CT scan revealed a basilar Skull fracture. The authors suggested that the bony skull fracture was the entry site of the air into the cranium followed by tracking down into the spinal canal. They postulated that the detection of spinal gas should lead to a search for significant cranial injuries.

Likewise, discovery of thoracic or lumbar intraspinal air should trigger a systematic investigation for other Major injuries. Because air must be dispersed from an air-contain- ing region to enter the spinal canal, a number of possible sites should be considered. This includes the lungs, mediastinum, mastoid cells, frontal sinuses, vertebral disks, and hollow organs, which can release air that may track into the spinal canal at different levels [6,7].

Intraspinal air can also originate directly from interver- tebral disks through the vacuum disk phenomenon. Initially described by Magnusson [8] in 1937, intervertebral disks develop fissures in the central part of the disk as they degenerate with the age. These fissures passively absorb gas from the surrounding tissues. The involved air is found to be composed mostly of nitrogen. If the disk herniates, especially in the case of major trauma, the gas can be released into the spinal canal causing spinal pneumorrhachis.

The possible differential diagnosis of gas within the spinal canal after trauma is therefore multitudinous. In our case, air was found within the lumbar spinal canal between the levels of the lumbar vertebral body 3 to 5. Possible sources were identified as the subcutaneous emphysema, the pneumothorax, the urethra tear, the pelvic fracture, or the intervertebral disks. Significant intervertebral disk injuries were ruled out with the CT scan. Although there was a small right-sided pneu- mothorax, no spinal air entrapment was identified on the thoracic spine level. However, it is possible that the air entered the spinal canal at the thoracic level and tracked down toward the lumbar spinal site. The pelvic fracture may have caused epidural air entrapment when the ascending lumbar veins that anastomose with the intervertebral veins are breached and air is tracked directly into the pelvic vasculature [1]. Considering these options, the air most likely originated from the subcutaneous and muscular emphysema by direct migration.

Large skin lacerations with facial tear can result in subcutaneous or intramuscular emphysema. When asso- ciated with a spinal meninges tear, it is possible for the air originating from the emphysema to migrate into the spinal canal at any location. Intraspinal air has been described secondary to basal skull fracture, instrumentation, Epidural abscess, or disk degeneration disease. However, intraspinal air occurring in association with a pelvic and abdominal trauma is extremely rare. Chimon and Cantos [1] have

reported 2 cases of spinal epidural air resulting from extensive pelvic injury.

Intraspinal air is often due to iatrogenic causes such as spinal surgery, lumbar puncture, or Epidural anesthesia. Scialdone and Wagle [9] reported a case of intraspinal air after a blunt chest trauma. They suspected that rostral migration of air may have occurred through either the epidural space or the communicating facial planes of the mediastinum, neck, and chest wall. These findings may suggest the presence of a communication between the subcutaneous emphysema of the neck and the epidural space of the spinal cord. In the epidural space of the spinal cord, the internal venous, which provides the venous drainage for the individual vertebrae of the spinal column, is related to the veins of the neck. Thus, in addition to the mechanisms mentioned above, epidural spinal air may have migrated from subcutaneous emphysema in the pelvic and lower abdomen to the epidural space via the Venous system.

There is no consensus for the treatment of intraspinal gas, because, in most cases, the condition is discovered inciden- tally. The intraspinal air is usually asymptomatic and not hazardous. Miguel et al [10] reported a case of air-trapping in the cervicothoracic epidural space causing radicular pain. Furthermore, intraspinal gas has been monitored and appears to dissipate relatively quickly, in as little as half a day after the initial injury under normal circumstances [3]. Nevertheless, oral steroid administration or percutaneous Needle aspiration has been described [4]. In any case, an initial period of observation is warranted because the air and adjacent symptoms may disappear spontaneously.

Conventional radiographs are often of little use for diagnosis of pneumorrhachis. The CT scan is the most valuable radiologic imaging technique for identifying intraspinal air. Furthermore, this modality demonstrates air better than magnetic resonance imaging [4]. Whenever intraspinal air is found during the diagnostic work-up of a trauma patient, hidden pneumothorax should be suspected and additional diagnostic procedures should be undertaken to rule this out. Magnetic resonance imaging is not reliable for detecting intraspinal gas. The CT scan is more sensitive for identifying this condition [6].

The importance of intraspinal air may not lie in the presence of the air itself, because it is usually not dangerous, but in its indication for identifying more precarious under- lying pathology or trauma sequence. Any injury that results in intraspinal air is significant, for example, a pneumothorax, disk herniation, ruptured hollow organs, or base skull fracture. Therefore, a CT scan of the head should be undertaken if cervical pneumorrhachis is discovered. A CT scan of the thorax, abdomen, and pelvis should be performed if intraspinal air is found at the thoracic or lumbar levels.

Although intraspinal gas is generally considered to be a benign phenomenon and self-limiting, it is evident from the available literature that air within the spinal canal at any level was an indicator of severe organ trauma and represented a diagnostic challenge for the Initial resuscitation period with its diagnostic and therapeutic steps. If an accidental finding of

Case Report

intraspinal air is present, a thorough investigation with full thoracic, lumbar, sacral CT scan should be undertaken to

References

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evaluate the origin and extent of the injury and to finally rule out Life-threatening causes. Therefore, management of traumatic intraspinal air is targeted at the Underlying etiology.

Oliver P. Gautschi MD Christel Hermann MD Department of neurosurgery Cantonal Hospital St Gallen 9000 St Gallen, Switzerland

E-mail address: [email protected]

Dieter Cadosch MD

Department of Orthopaedic and Trauma Surgery

Royal Perth Hospital Perth 6000, Western Australia

doi:10.1016/j.ajem.2007.11.042

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