Hamman syndrome is defined as dissection of air in mediastinum and skin fascia usually due to increased intrathoracic pressure. The air leak tends to make its way into pleural and pericardial layers; however, in rare instances air can also dissect into epidural spaces, regarded as pneumorrhachis. We present a case of a young male with a history of polysubstance abuse and e-vaping, who presented with symptoms of altered mental status. Given the concerning physical examination, a computed tomography of the chest was undertaken, which showed pneumothorax, pneumomediastinum and pneumorrhachis. The patient was closely monitored in the intensive care unit and improved after symptomatic management. The symptoms of pneumorrhachis depend on the volume and location of air in intracranial and intraspinal space. Although asymptomatic in our case, it is crucial for clinicians to be aware that pneumorrhachis with Hamman syndrome can potentially cause neurological deficits and cardiopulmonary arrest in severe cases due to increased intraspinal and intracranial hypertension, emphasising the need for close monitoring.
CONCLUSIONS: Elevated intrathoracic pressure generated by deep inhalation of an aerosolised product is one of the triggers of air dissection in pleural, pericardial, and mediastinal regions. In rare instances, air can also translocate into intracranial and intraspinal spaces, which is referred to as pneumorrhachis.Mostly asymptomatic, pneumorrhachis has the potential to develop acute neurological deficits due to increased intracranial and intraspinal pressure, validating the need for acute monitoring.Most cases of pneumorrhachis are managed conservatively. However, severe cases warrant decompression or high concentrations of oxygen administration to facilitate air absorption.

Pneumorrhachis, a rare clinical entity, refers to the presence of air in the spinal canal. Air can enter the spinal canal through various pathways, including the lungs and mediastinum (the space between the lungs), or directly from external sources due to trauma or infection. In rare cases, pneumorrhachis may result from repeated secondary Valsalva maneuvers, which is a complication of large-area pneumothorax. In this case report, we discuss a 36-year-old male patient who was involved in a high-intensity road accident. The injury assessment revealed significant findings including a large left pneumothorax, a right pneumothorax, multiple rib fractures, and the presence of pneumorrhachis. The entry of air into the spinal canal originated from the pleural space, likely through injuries to the parietal pleura. Rarely reported, closed thoracic trauma is an exceptional cause of pneumorrhachis. This unique mechanism of injury has been described in a limited number of publications addressing traumatic pneumorrhachis. The identification of pneumorrhachis in a traumatized patient should prompt further investigation to explore other potential injuries that may elucidate the formation of this intraspinal gas collection.

BACKGROUND: Pneumomediastinum and pneumorrachis are rare complications following epidural analgesia, that can either be asymptomatic or rarely can produce mild to moderate severity symptoms. Most reported cases regarding the presentation of these two entities with epidural analgesia concern asymptomatic patients, however there are cases reporting post-dural puncture headache and respiratory manifestations.
METHODS: We present a case where a combined lumbar epidural and spinal anesthesia was performed using the loss of resistance to air technique (LOR), on a 78-year-old Greek (Caucasian) male undergoing a total hip replacement. Despite being hemodynamically stable throughout the operation, two hours following epidural analgesia the patient manifested a sudden drop in blood pressure and heart rate that required the administration of adrenaline to counter. Pneumomediastinum, pneumorrachis and paravertebral soft tissue emphysema were demonstrated in a Computed Tomography scan. We believe that injected air from the epidural space and surrounding tissues slowly moved towards the mediastinum, stimulating the para-aortic ganglia causing parasympathetic stimulation and therefore hypotension and bradycardia.
CONCLUSIONS: Anesthesiologists should be aware that epidural analgesia using the LOR to technique injecting air could produce a pneumomediastinum and pneumorrachis, which in turn could produce hemodynamic instability via parasympathetic stimulation.

A three‑year‑old domestic shorthair cat was referred for treatment of pelvic limb paralysis. Imaging examinations revealed air in the spinal canal (pneumorrhachis). A right‑sided hemilaminectomy was performed to decompress the spinal cord, which led to full resolution of the symptoms within four weeks after the procedure. To our knowledge, this is the first reported case of spontaneous pneumorrhachis in a cat. As there are no treatment standards, we would like to add to their creation. The available literature on pneumorrhachis has also been reviewed.

Pneumorrhachis (PR) is an uncommon condition characterized by the accumulation of air within the spinal canal. This finding may occur due to various causes, mostly after trauma and medical procedures. It can manifest with various features depending on the underlying cause, the location, and the extent of the air trapped. Clinically, the symptoms in affected patients can span a spectrum, ranging from being asymptomatic to manifesting as radiculopathies resulting from compression. The pneumorrhachis-related cauda equina syndrome is incredibly rare and typically appears as a large volume of air causing compression or irritation of the nerve roots in the lower spinal cord. In this report, we present a female patient whose cauda equina syndrome developed as a result of accidental extradural pneumorrhachis after epidural injection in the lumbar spine.

Pneumorrhachis is a medical condition that refers to the presence of air within the spinal canal. Many circumstances, including trauma, infection, or medical procedures, might lead to this syndrome.In some cases, pneumorrhachis may not cause any symptoms and can resolve on its own. However, it can also be associated with more severe underlying conditions, such as spinal fractures, spinal infections, or underlying lung pathologies that lead to air escaping into the spinal canal. In this case we report an incidental finding of pneumorrhachis in a patient who came to our attention for suspected sepsis.

UNASSIGNED: A 57-year-old man presented with odynophagia for 1 week was referred for FDG PET/CT scan to rule out recurrent hypopharyngeal cancer. The FDG PET/CT showed hypermetabolic lesions in hypopharyngeal area and adjacent cervical spine with pneumorrhachis, the presence of intraspinal air, on attenuation CT images, which might indicate a life-threatening infection. An emergency MRI confirmed the presence of cervical spondylodiscitis with an epidural abscess. The patient rapidly progressed to quadriplegia and difficulty voiding on the same day as the PET/CT scan, leading to emergent operation. The patient received antibiotics treatment and discharged 4 months later without evidence of cancer recurrence.

Pneumorrhachis (PR) is defined as presence of free air in the spinal canal. Traumatic PR is very rare, and its exact incidence and pathogenesis is unknown. A comprehensive literature search was performed using the PubMed, Cochrane Library, Google Scholar and Scopus databases to identify articles relevant to traumatic PR published till January 2023. A total of 34 resources were selected for inclusion in this narrative review. Traumatic PR can be classified anatomically into epidural and intradural types. In the epidural type, air is present peripherally in the spinal canal and the patients are usually asymptomatic. In contrast, in intradural PR, air is seen centrally in the spinal canal and patients present with neurological symptoms, and it is a marker of severe trauma. It is frequently associated with traumatic pneumocephalus, skull fractures or thoracic spine fracture. Computed tomography (CT) is considered to be the diagnostic modality of choice. Epidural PR is self-limited and patients are generally managed conservatively. Patients with neurological symptoms or persistent air in spinal canal require further evaluation for a potential source of air leak, with a need for surgical intervention. Differentiation between epidural and intradural PR is important, because the latter is an indication of severe underlying injury. CT imaging of the entire spine must be performed to look for extension of air, as well as to identify concomitant skull, torso or spinal injuries Most patients are asymptomatic and are managed conservatively, but a few may develop neurological symptoms that need further evaluation and management.

The occurrence of pneumorrhachis (PR), defined as the presence of air within the spinal canal, presents a complex clinical picture with diverse etiological factors. We report an exceedingly rare case of PR arising from locally advanced rectal cancer accompanied by a pre-sacral abscess. This report aims to enhance awareness and understanding of rare causes of PR within the medical community, particularly among surgeons engaged in emergency procedures. The patient survived the acute phase of the disease through multiple surgical interventions and admission to the intensive care unit, but succumbed to cardiovascular complications three weeks later. We also offer a brief review of the literature concerning PR originating from the colorectal lumen.

Computed tomography (CT) is a commonly used modality in small animal veterinary medicine. Anecdotally, gas bubbles are frequently identified in small animals undergoing thoracic CT examination. The aim of this retrospective observational study was to record the occurrence and prevalence of vascular and extravascular gas in routine thoracic CT examinations in dogs and cats. Patients with any clinical signs of diseases   related to soft tissue gas were excluded. A total of 84 canine studies and 90 feline studies were included, detecting gas in 66.7% of all studies, with gas more likely to be detected in canine studies (75.0%) than in feline cases (58.9%) (P = 0.009). Canine studies were more likely to have gas detected in postcontrast studies than in precontrast studies (P = 0.016). Intravascular gas was detected in 65.5% of all included studies (75% canine and 56.7% feline). Extravascular gas was detected in 13.8% of all studies (14.3% canine, 13.3% feline), with gas detected in the vertebral canal of 8.62% of all studies (canine 11.9%, feline 5.56%) and within fascial planes in 5.75% of all studies (canine 2.38%, feline 8.89%). In conclusion, gas bubbles were identified in the majority of canine and feline thoracic CT studies without clinical evidence of a pathologic etiology.