Oxygen Therapy with High-Flow Nasal Cannula as an Effective Treatment for Perioperative Pneumocephalus: Case Illustrations and Pathophysiological Review.

Pneumocephalus (PNC) is a condition in which when air is trapped inside the intracranial vault. The causes are varied, but include trauma and intracranial surgery. Treatment of PNC typically consists of augmenting patient oxygenation with the attempt of washing out pulmonary nitrogen, creating a gradient in which nitrogen in the intracranial air bubble diffuses out of the lungs via the blood. Though several high flow methods have been tested, the ideal mode of oxygenation has not fully been investigated. Here we present 3 cases of post-operative PNC who we felt were symptomatic from PNC. With administration of high-flow nasal cannula (HFNC), all patients improved both clinically and radiographically within a few hours, faster than in both anecdotal experience and published trials. Due to its steady FiO2 administration, positive pressure, comfort, and low side-effect profile, HFNC may be the ideal mode of oxygen delivery in PNC. We present a review of the physiology of PNC and the characteristics of several oxygen delivery systems to build a case for HFNC in this disease process.

Pneumocephalus and seizures following epidural steroid injection.

We describe a patient with pneumocephalus following an epidural steroid injection (ESI) who presented with altered mental status, headache, focal neurologic findings and seizures. Pneumocephalus has rarely been described following ESI. A 34-year-old female presented with an altered level of consciousness worsening over approximately 18h following an ESI for lumbar back pain. She had associated headache, right-sided facial twitching and right upper extremity weakness. A brain CT scan revealed pneumocephalus in the right lateral ventricle and quadrigeminal plate cistern. While in the emergency department she experienced a self-limited generalized seizure. She was admitted and her symptoms persisted. Seven days following admission she was discharged to a rehabilitation facility, but her arm weakness persisted for greater than a month before resolving. Epidural anesthesia relies on the localization of the epidural space. The manual loss of resistance technique is widely used to identify the epidural space. The incidence of adverse effects is unknown. Case reports noting complications associated with this technique have been reported; rarely including pneumocephalus. Complications from the pneumocephalus are even less commonly reported. Though rare following an ESI and generally self-limited without complication, pneumocephalus should be considered in the differential diagnosis when evaluating a patient with neurologic deficits after instrumentation.

Spontaneous Intraventricular Pneumocephalus.

BACKGROUD: Pneumocephalus without a known underlying cause is defined as spontaneous pneumocephalus. Few patients of intraventricular pneumocephalus have been reported. PATIENT PRESENTATION: An 84-year-old man presented with dysarthria and incontinence. Computed tomography revealed an intraventricular pneumocephalus, thinning in the petrous bone, fluid in the air cells, and cleft in temporal lobe. A right subtemporal extradural approach was taken to detect bone-/-dural defects, and a reconstruction was performed using a musculo-pericranial flap. CONCLUSION: This is the first patient of an isolated intraventricular spontaneous pneumocephalus without any other site air involved. Surgical approaches to repair such bone and dura defects should be considered an appropriate option.

[Multiple pneumocele associated with temporal bone hyperpneumatization]. / Mnozhestvennoe pnevmotsele pri giperpnevmatizatsii visochnoi kosti.

The authors consider in brief epidemiology, diagnostics, and variants of the surgical treatment of the rare clinical condition pneumocele and pneumoencephalocele of the temporal bone. Diagnostic and surgical modalities for the management of multiple pneumocele associated with temporal bone hyperpneumatization are discussed.

[Cerebral circulation pathophisiology into pneumocephalus craniocerebral dispoportion].

We included 19 patients with a different intensity postoperative pneumocephalus and an inadequate postoperative awakening. Intracranial CT excluded postoperative complications (oedema, haematoma, hidrocephalus) and diagnosed a pneumocephalus (above the frontal and temporal lobes and in the cerebral ventricular system). In two hours after operation we found systolic linear blood flow velocity (BFV syst.) decrease in the extracranial part of internal carotic artery (ICA) (p < 0.001) in patients with pneumocephalus and inadequate postoperative awakening. But in 24-48 hours after operation we diagnosed BFV syst. elevation in the ICA extracranial part (p < 0.001) and preumocephalus diminution in patients with a recovered consciousness.

Tension pneumocephalus as a result of endonasal surgery: an uncommon intracranial complication.

Tension pneumocephalus (TP) is a clinical entity characterized by continued build-up of air within the cranial cavity, leading to abnormal pressure exerted upon the brain and subsequent neurologic deterioration, due to development of a mass effect and potentially a herniation syndrome. Intracranial complications of endoscopic sinus surgery (ESS) and other endonasal procedures are fortunately very rare, occurring in less than 3% of cases. We report 4 cases of small bone defects (<3 mm) in the anterior cranial base accompanied by TP, caused by ESS and other endonasal procedures. The pathophysiology and management of this clinical entity is discussed with a pertinent literature. Four patients with small (<3 mm) skull base defects were identified. All patients presented with active cerebrospinal fluid leaks. CT scans showed intracranial tension pneumocephalus. Using image-guided endoscopic techniques, all defects were addressed with multi-layer repair. Closure was achieved in all patients on the first attempt, with an average follow-up of 36 months. Tension pneumocephalus is a rare event that can occur as a result of traumatic or iatrogenic violation of the dura and should be considered in all patients presenting with altered mental status after endoscopic sinus surgery or other surgical and diagnostic procedures that violate either the cranial or spinal dura. Because of the potential for rapid clinical deterioration and death, prompt brain imaging is warranted to rule out the diagnosis, and urgent neurosurgical consultation is indicated for definitive management.

Delayed spontaneous pneumocephalus in ventriculoperitoneal shunting: two case reports and literature review.

Spontaneous pneumocephalus following cerebrospinal fluid shunt is a rare complication. In most cases, the air enters in the intracranial cavity via a skull base defect. We report 2 cases of delayed tension pneumocephalus, secondary to ventriculoperitoneal shunt, and review the etiopathogenesis, prevention and treatment of this condition.

Spontaneous pneumocephalus after commercial air travel complicated by meningitis.

BACKGROUND: Pneumocephalus usually results from trauma, infection, neoplasm, or iatrogenic causes. Barotrauma-induced spontaneous pneumocephalus is extremely rare, usually seen in divers or occassionally with air travel. CASE REPORT: We report a case of a 61-yr-old female presenting with confusion, fever, and respiratory failure one day after developing sudden nausea, vomiting, and headache during descent on a commercial airliner. Pneumocephalus and meningitis were present on admission. Sinus computed tomography (CT) showed pansinusitis and a tiny bone defect in the posterior wall of the right sphenoid sinus, through which a cisternogram later showed free communication with the prepontine cistern. An orbital CT 2 yr earlier after a fall showed the bone defect, with no other areas of abnormality or fracture. After repair of defects by otolaryngology and appropriate antibiotics, she did well and was eventually discharged. DISCUSSION: Changes in aircraft cabin pressure likely resulted in rupture of dura and arachnoid layers beneath the pre-existing bony defect, predisposed by existing sinus disease. The pathophysiology, implications, and potential sources of spontaneous pneumocephalus, as well as risks of postcraniotomy and post-trauma air-travel, are discussed.

[Surgery in the sitting position : anesthesiological considerations]. / Operative Eingriffe in sitzender Position : Anästhesiologische Besonderheiten.

Surgical interventions in the sitting position are intended to optimize surgical conditions by reducing bleeding in the operation field and improving the surgical approach. There are, however, some potentially life-threatening risks associated with surgery in the sitting position. Of these risks, air embolism is one of the most serious complications and should be detected immediately in order to initiate specific countermeasures. In addition to standard monitoring procedures, transthoracic Doppler ultrasound and transesophageal echocardiography are valuable methods used to detect the presence of air in the vasculature. If an air embolism becomes apparent, further targeted measures are needed to prevent or aggressively treat the progression of potentially life-threatening consequences.

Delayed pneumocephalus induced by repeated percutaneous aspiration after spinal surgery: A case report and literature review.

RATIONALE: Severe tension pneumocephalus can lead to drowsiness, coma, and even brain hernia and death. The occurrence of delayed pneumocephalus after spinal surgery is rarely reported and often ignored. Herein, we report a case of delayed pneumocephalus after repeated percutaneous aspiration following spinal surgery. PATIENT CONCERNS: A 55-year-old man was admitted in October 2020 because of aggravation in bilateral lower limb weakness and dysuria for seven days. He was diagnosed with liver cancer a year ago, and he underwent several operations because of tumor recurrence. The patient underwent thoracic vertebrae tumor excision on this admission, and no cerebrospinal fluid leakage was discovered during surgery. After the third drainage by percutaneous aspiration, the patient complained of severe headache and vomiting on postoperative day 16. DIAGNOSIS: Emergency brain computed tomography revealed massive pneumocephalus. INTERVENTIONS: Thereafter, suction drainage was discontinued, and he was placed on bed rest and administered intravenous mannitol. OUTCOMES: Repeated computed tomography showed complete resolution of the pneumocephalus after five days. LESSONS: Wound exudates and cystic fluid after spinal surgery should be differentiated from cerebrospinal fluid leakage. Reckless percutaneous aspirations can form pneumocephalus in patients with an occult dural injury, and pneumocephalus can occur up to 16 days after surgery. Early diagnosis of pneumocephalus is crucial to avoid severe consequences.

Pneumocephalus and air travel: an experimental investigation on the effects of aircraft cabin pressure on intracranial pressure.

This study investigates the effects of aircraft cabin pressure on intracranial pressure (ICP) elevation of a pneumocephalus patient. We propose an experimental setup that simulates the intracranial hydrodynamics of a pneumocephalus patient during flight. It consists of an acrylic box (skull), air-filled balloon [intracranial air (ICA)], water-filled balloon (cerebrospinal fluid and blood) and agarose gel (brain). The cabin was replicated using a custom-made pressure chamber. The setup can measure the rise in ICP during depressurization to levels similar to that inside the cabin at cruising altitude. ΔICP, i.e. the difference between mean cruising ICP and initial ICP, was found to increase with ICA volume and ROC. However, ΔICP was independent of the initial ICP. The largest ΔICP was 5 mmHg; obtained when ICA volume and ROC were 20 ml and 1,600 ft/min, respectively. The postulated ICA expansion and the subsequent increase in ICP in pneumocephalus patients during flight were successfully quantified in a laboratory setting. Based on the quantitative and qualitative analyses of the results, an ICA volume of 20 ml and initial ICP of 15 mmHg were recommended as conservative thresholds that are required for safe air travel among pneumocephalus patients. This study provides laboratory data that may be used by doctors to advise post-neurosurgical patients if they can safely fly.

Intraoperative High Impedance Levels During Placement of Deep Brain Stimulating Electrode.

BACKGROUND AND IMPORTANCE: Deep brain stimulation (DBS) is a well-established treatment for medically refractory Parkinson's disease (PD), essential tremor (ET), and dystonia. The field of DBS is expanding and techniques are under investigation for the treatment of several neurological disorders. A critical component of the success of these procedures depends significantly on the reliability and durability of devices implanted. Immediate feedback during surgery often gives the surgeon and patient a sense of confidence of long term success. When impedances are found to be elevated during the implantation of the DBS leads, appropriate trouble shooting measures are critical. CLINICAL PRESENTATION: We present a 73-yr-old male undergoing awake subthalamic DBS with microelectrode recordings for severe PD. Once the optimal trajectory and depth were ascertained, the permanent DBS electrode was placed. High impedances were recorded. Troubleshooting procedures were performed and were all negative as to the cause of the values. Correct impedance levels of the DBS electrode was confirmed with extracranial testing, but continued high values were found again with intracranial positioning of the electrode. A postoperative computerized tomography (CT) scan confirmed intracranial air surrounding all of the contacts. The patient went on to outpatient programming with excellent clinical results. CONCLUSION: The presence of pneumocephalus surrounding the DBS lead contacts at the target nucleus may have accounted for the intraoperative impedance findings. When all troubleshooting checks have not identified an explanation for the high impedances, intraoperative imaging may demonstrate pneumocephalus around the lead contacts, which should resolve and impedances return to normal values.

Cardiac arrest associated with pneumorrhachis and pneumocephalus after epidural analgesia: two case reports.

BACKGROUND: Epidural analgesia has become a common procedure to provide excellent pain relief with few complications. Pneumorrhachis and pneumocephalus are rare complications of unintentional dural puncture and injection of air into the subarachnoid or subdural space. No cases of cardiac arrest associated with these complications have been reported in the literature previously. CASE PRESENTATION: We report cases of pneumorrhachis and pneumocephalus in two Korean women who previously visited a local pain clinic and underwent epidural analgesia. Thereafter, they were admitted to the emergency department with cardiac arrest. Cardiopulmonary resuscitation was performed on these patients, and return of spontaneous circulation was achieved. The brain and spine computed tomographic scans showed pneumorrhachis and pneumocephalus, respectively. These cases demonstrate that pneumorrhachis and pneumocephalus may occur after epidural analgesia, which may be associated with cardiac arrest in patients. CONCLUSIONS: If cardiac arrest occurs after epidural analgesia, pneumocephalus and pneumorrhachis should be considered as its cause. Although epidural analgesia is a common procedure, caution is warranted during this procedure.

Pneumocephalus after Pancoast's tumor surgery: to be or not to be conservative?

We report a case of a 62-year-old man affected by Pancoast's tumor who developed pneumocephalus 17 days after right upper lobectomy with en bloc resection of the first three ribs and C8-D1 branches of the brachial plexus. The patient complained of aphasia, disorientation and sphincterial release. A chest and brain-CT scan showed a right apical pneumothorax associated with a massive pneumocephalus of the ventricles and of the subarachnoidal spaces. A pneumoperitoneum was also seen. The patient was treated using pleural drainages, Trendelenburg's position and antibiotic therapy. Clinical and radiological remission was achieved after 12 days of additional hospital stay.

Why Does Threshold Level Change in Transcranial Motor-evoked Potentials During Surgery for Supratentorial Lesions?

BACKGROUND: Rising threshold level during monitoring of motor-evoked potentials (MEP) using transcranial electrical stimulation (TES) has been described without damage to the motor pathway in the cranial surgery, suggesting the need for monitoring of affected and unaffected hemisphere. We aimed to determine the factors that lead to a change in threshold level and to establish reliable criteria for adjusting stimulation intensity during surgery for supratentorial lesions. MATERIALS AND METHODS: Between October 2014 and October 2015, TES-MEP were performed in 143 patients during surgery for unilateral supratentorial lesions in motor-eloquent brain areas. All procedures were performed under general anesthesia using a strict protocol to maintain stable blood pressure. MEP were evaluated bilaterally to assess the percentage increase in threshold level, which was considered significant if it exceeded 20% on the contralateral side beyond the percentage increase on the ipsilateral side. Patients who developed a postoperative motor deficit were excluded. Volume of subdural air was measured on postoperative magnetic resonance imaging. Logistic regression was performed to identify factors associated with the intraoperative recorded changes in threshold level. RESULTS: A total of 123 patients were included in the study. On the affected side, 82 patients (66.7%) showed an increase in threshold level, which ranged from 2% to 48% and 41 patients (33.3%) did not show any change. The difference to the unaffected side was under 20% in all patients. The recorded range of changes in the systolic and mean pressure did not exceed 20 mm Hg in any of the patients. Pneumocephalus was detected on postoperative magnetic resonance imaging scans in 87 patients (70.7%) and 81 of them (93.1%) had an intraoperative increase in threshold level on either sides. Pneumocephalus was the only factor associated with an increase in threshold level on the affected side (P<0.001), while each of pneumocephalus and length of the procedure correlated with a change in threshold level on the unaffected side (P<0.001 and 0.032, respectively). CONCLUSIONS: Pneumocephalus was the only factor associated with increase in threshold level during MEP monitoring without damaging motor pathway. Threshold level on the affected side can rise up to 48% without being predictive of postoperative paresis, as long as the difference between the increased threshold of the affected and unaffected side is within 20%. Changes in systolic or mean blood pressure within a range of 20 mm Hg do not seem to influence intraoperative MEP.

Alleviation of intracranial air using carbon dioxide gas during intraventricular tumor resection.

OBJECTIVES/PURPOSES: Postoperative vomiting occurs more frequently in patients after intraventricular surgery than after other intracranial surgeries. This has been attributed to intracranial air. Carbon dioxide gas (CO2) has properties beneficial to the treatment of some medical disorders, displaying a higher specific gravity and more rapid absorption into surrounding tissues than air. We therefore, attempted to replace air with CO2 during intra- and paraventricular tumor resections. The aim of the present study was to elucidate whether intracranial air after intraventricular surgery could be alleviated safely using CO2, and investigate its clinical usefulness. PATIENTS AND METHODS: CO2 was introduced into the subdural space at 2l/min through a silicon tube from time of dural incision to closure. Subjects comprised 40 patients alternately assigned to one of two groups: the trial group (n=20) receiving CO2 treatment; and controls (n=20) without CO2 treatment. RESULTS: Intra- and postoperatively, no patients showed complications caused by CO2 treatment. Postoperatively, intraventricular gas shown on CT scans disappeared significantly sooner in the trial group than in controls. Frequency of postoperative vomiting was significantly lower in the trial group than in controls. CONCLUSION: Intracranial air after intraventricular surgery can be safety alleviated using CO2.

Tension pneumoventricle.

We report a case of tension pneumoventricle in a patient who underwent excision of a midbrain tectal plate tumour via a supracerebellar infratentorial approach while in the sitting position. Tension pneumoventricle was diagnosed when the patient's clinical condition deteriorated rapidly early in the postoperative period. An urgent computed tomography scan of the head revealed the presence of air in the frontal and temporal horns of the lateral ventricles and blood in the third and fourth ventricles. An emergency external ventricular drain insertion was performed, resulting in prompt recovery. We believe the contributing factors resulting in such rapid development of tension pneumoventricle were the patient's sitting position, pre-existing hydrocephalus, breach of the third ventricle during surgery and the presence of blood in the third and fourth ventricles.

Tension pneumocephalus--a rare complication of radiotherapy: a case report.

We present a rare case of tension pneumocephalus due to high-dose radiotherapy used to treat nasopharyngeal carcinoma. A skull base defect causing tension pneumocephalus was identified and was repaired successfully. The case emphasizes the importance of careful consideration before applying irradiation treatment to patients with head and neck malignancy and urges early detection of potentially life-threatening complications.