Intracranial Air Research Articles

Intentional Insertion of Air to Predict the Diagnostic Accuracy of Stereotactic Biopsy and a Uniform Grading System for Reporting

Background and Objectives: Stereotactic biopsies are a relatively safe and reliable way of tissue diagnosis and characterization of eloquent area lesions/neoplasm. However, predicting the accuracy of the site of biopsy with the desired/planned site is not always possible. We describe a technique to identify the precise location of the biopsy site in the post-operative computed tomography (CT) scan using the injection of a low volume of air into the biopsy cannula. Methods: Hundred consecutive biopsies were performed in 80 adults/20 children (59 males/41 females, median age 51 years) over 3 years, consisting of 75 frameless and 25 frame-based stereotactic biopsies. After the biopsy specimens had been collected, a small volume of air (median 1 cc) was injected into the site. Post-operative CT was done within 4 hours of the biopsy to see the site of the air bubble, and the same was correlated with the histopathological accuracy. Results: Intra-cranial air in the selected target was present in 95 patients (Grade 1 and 2), while the air was seen in the track (Grade 3) in 3% and at an unrelated site (Grade 4) in 2% of cases. Both Grade 4 biopsies were negative on histopathology (diagnostic yield = 98%). Two negative biopsies were reported, which were both predicted with the Grade 4 biopsy. The grading allowed uniform reporting across series and eliminated the chance of upgrading/downgrading the report due to wrong site sampling within the lesion/neoplasm. Conclusion: The air-injection manoeuvre proposed for use in stereotactic biopsies of intra-cranial mass lesions is a safe and reliable technique that allows the exact biopsy site to be located without any related complications.

Brain Shift during Staged Deep Brain Stimulation for Movement Disorders

Introduction: Deep brain stimulation (DBS) is a routine neurosurgical procedure utilized to treat various movement disorders including Parkinson’s disease (PD), essential tremor (ET), and dystonia. Treatment efficacy is dependent on stereotactic accuracy of lead placement into the deep brain target of interest. However, brain shift attributed to pneumocephalus can introduce unpredictable inaccuracies during DBS lead placement. This study aimed to determine whether intracranial air is associated with brain shift in patients undergoing staged DBS surgery. Methods: We retrospectively evaluated 46 patients who underwent staged DBS surgery for PD, ET, and dystonia. Due to the staged nature of DBS surgery at our institution, the first electrode placement is used as a concrete fiducial marker for movement in the target location. Postoperative computed tomography (CT) images after the first electrode implantation, as well as preoperative, and postoperative CT images after the second electrode implantation were collected. Images were analyzed in stereotactic targeting software (BrainLab); intracranial air was manually segmented, and electrode shift was measured in the x, y, and z plane, as well as a Euclidian distance on each set of merged CT scans. A Pearson correlation analysis was used to determine the relationship between intracranial air and brain shift, and student’s t test was used to compare means between patients with and without radiographic evidence of intracranial air. Results: Thirty-six patients had pneumocephalus after the first electrode implantation, while 35 had pneumocephalus after the second electrode implantation. Accumulation of intracranial air following the first electrode implantation (4.49 ± 6.05 cm³) was significantly correlated with brain shift along the y axis (0.04 ± 0.35 mm; r (34) = 0.36; p = 0.03), as well as the Euclidean distance of deviation (0.57 ± 0.33 mm; r (34) = 0.33; p = 0.05) indicating statistically significant shift on the ipsilateral side. However, there was no significant correlation between intracranial air and brain shift following the second electrode implantation, suggesting contralateral shift is minimal. Furthermore, there was no significant difference in brain shift between patients with and without radiographic evidence of intracranial air following both electrode implantation surgeries. Conclusion: Despite observing volumes as high as 22.0 cm³ in patients with radiographic evidence of pneumocephalus, there was no significant difference in brain shift when compared to patients without pneumocephalus. Furthermore, the mean magnitude of brain shift was <1.0 mm regardless of whether pneumocephalus was presenting, suggesting that intracranial air accumulation may not produce clinical significant brain shift in our patients.

Predictive value of facial motor–evoked potential and electromyography for facial motor function in vestibular schwannoma surgery

PurposeIntraoperative neuromonitoring (IONM) aims to preserve facial nerve (FN) function during vestibular schwannoma (VS) surgery. However, current techniques such as facial nerve motor evoked potentials (FNMEP) or electromyography (fEMG) alone are limited in predicting postoperative facial palsy (FP). The objective of this study was to analyze a compound fEMG/FNMEP approach.MethodsIntraoperative FNMEP amplitude and the occurrence of fEMG-based A-trains were prospectively determined for the orbicularis oris (ORI) and oculi (OCU) muscle in 322 VS patients. Sensitivity and specificity of techniques to predict postoperative FN function were calculated. Confounding factors as tumor size, volume of intracranial air, or IONM duration were analyzed.ResultsA relevant immediate postoperative FP was captured in 105/322 patients with a significant higher risk in large VS. While fEMG demonstrated a high sensitivity (77% and 86% immediately and 15 month postoperative, respectively) for identifying relevant FP, specificity was low. In contrast, FNMEP have a significantly higher specificity of 80.8% for predicting postoperative FP, whereas the sensitivity is low. A retrospective combination of techniques demonstrated still an incorrect prediction of FP in ~ 1/3 of patients.ConclusionsFNMEP and fEMG differ in sensitivity and specificity to predict postoperative FP. Although a combination of IONM techniques during VS surgery may improve prediction of FN function, current techniques are still inaccurate. Further development is necessary to improve IONM approaches for FP prediction.

The advantages of general anesthesia subthalamic deep brain stimulation for Parkinson's disease in the enhanced recovery after surgery: A randomized clinical trial.

With advancements in imaging and microelectrode recording techniques, general anesthesia (GA) has emerged as an alternative option for Parkinson's disease (PD) patients undergoing subthalamic nucleus deep brain stimulation (STN-DBS). In this study, we compared the advantages and disadvantages of using GA and local anesthesia for STN-DBS in enhanced recovery after surgery (ERAS). Surgical outcomes of STN-DBS were evaluated using the unified PD rating scales (UPDRS). CT and magnetic resonance imaging scans are used to evaluate intracranial conditions. State-trait anxiety inventory and hospital anxiety and depression scale are used to evaluate patients' perioperative psychology. Anesthesia method does not significantly impact the accuracy of microelectrode placement or the improvement of postoperative symptoms. However, the local anesthesia group had a higher incidence of intracranial air, as well as higher rates of postoperative complications such as headache, dizziness, vomiting, and delirium. GA effectively alleviated preoperative anxiety and resulted in lower levels of perioperative anxiety and psychological stress compared to local anesthesia. Additionally, the GA group had shorter surgery duration, earlier ambulation, and a shorter average hospital stay. DBS under GA is safe and effective. Due to shorter surgical duration, reduced occurrence of perioperative complications, effective reduction of preoperative anxiety, and faster postoperative recovery, DBS under GA is better aligned with the concept of ERAS.

Ethmoidal sinus osteoma associated with Pneumocephalus

The most common causes of intracranial air are head trauma and neurosurgical procedures. Less common etiologies include infection due to gas-forming organisms, mucoceles, tumors, congenital neuroenteric cysts, and dural defects. Here, we present a case of an ethmoidal sinus osteoma associated with pneumocephalus. Osteomas of the paranasal sinuses are benign, often asymptomatic, tumors that progress very slowly. Endocranial development of an osteoma can breach the dura mata, allowing air to enter the cranium producing pneumocephalia which leads to severe neurological deficiencies. Pneumocephalia is an exceptional complication of osteoma.

MER and increased operative time are not risk factors for the formation of pneumocephalus during DBS

Although only recently directional leads have proven their potential to compensate for sub-optimally placed electrodes, optimal lead positioning remains the most critical factor in determining Deep Brain Stimulation (DBS) outcome. Pneumocephalus is a recognized source of error, but the factors that contribute to its formation are still a matter of debate. Among these, operative time is one of the most controversial. Because cases of DBS performed with Microelectrode Recordings (MER) are affected by an increase in surgical length, it is useful to analyze whether MER places patients at risk for increased intracranial air entry. Data of 94 patients from two different institutes who underwent DBS for different neurologic and psychiatric conditions were analyzed for the presence of postoperative pneumocephalus. Operative time and use of MER, as well as other potential risk factors for pneumocephalus (age, awake vs. asleep surgery, number of MER passages, burr hole size, target and unilateral vs. bilateral implants) were examined. Mann-Whitney U and Kruskal-Wallis tests were utilized to compare intracranial air distributions across groups of categorical variables. Partial correlations were used to assess the association between time and volume. A generalized linear model was created to predict the effects of time and MER on the volume of intracranial air, controlling for other potential risk factors identified: age, number of MER passages, awake vs. asleep surgery, burr hole size, target, unilateral vs. bilateral surgery. Significantly different distributions of air volume were noted between different targets, unilateral vs. bilateral implants, and number of MER trajectories. Patients undergoing DBS with MER did not present a significant increase in pneumocephalus compared to patients operated without (p = 0.067). No significant correlation was found between pneumocephalus and time. Using multivariate analysis, unilateral implants exhibited lower volumes of pneumocephalus (p = 0.002). Two specific targets exhibited significantly different volumes of pneumocephalus: the bed nucleus of the stria terminalis with lower volumes (p < 0.001) and the posterior hypothalamus with higher volumes (p = 0.011). MER, time, and other parameters analyzed failed to reach statistical significance. Operative time and use of intraoperative MER are not significant predictors of pneumocephalus during DBS. Air entry is greater for bilateral surgeries and may be also influenced by the specific stimulated target.

Durotomy- and Irrigation-Related Serious Adverse Events During Spinal Endoscopy: Illustrative Case Series and International Surgeon Survey.

Durotomy during endoscopic spine surgery can cause a patient's neurological or cardiovascular status to deteriorate unexpectedly intra- or postoperatively. There is currently limited literature regarding appropriate fluid management strategies, irrigation-related risk factors, and clinical consequences of incidental durotomy during spinal endoscopy, and no validated irrigation protocol exists for endoscopic spine surgery. Thus, the present article sought to (1) describe 3 cases of durotomy, (2) investigate standard epidural pressure measurements, and (3) survey endoscopic spine surgeons on the incidence of adverse effects believed to result from durotomy. The authors first reviewed clinical outcomes and analyzed complications in 3 patients with intraoperatively recognized incidental durotomy. Second, the authors conducted a small case series with intraoperative epidural pressure measurements during gravity-assisted irrigated video endoscopy of the lumbar spine. Measurements were conducted on 12 patients with a transducer assembly that was introduced through the endoscopic working channel of the RIWOSpine Panoview Plus and Vertebris endoscope to the decompression site in the spine. Third, the authors conducted a retrospective, multiple-choice survey of endoscopic spine surgeons to better understand the frequency and seriousness of problems they attributed to irrigation fluid escaping from the surgical decompression site into the spinal canal and neural axis. Descriptive and correlative statistical analyses were performed on the surgeons' responses. In the first part of this study, durotomy-related complications during irrigated spinal endoscopy were observed in 3 patients. Postoperative head computed tomographic (CT) images revealed massive blood in the intracranial subarachnoid space, the basal cisterns, the III and IV ventricle, and the lateral ventricles characteristic of an arterial fisher grade IV subarachnoid hemorrhage, and hydrocephalus without evidence of aneurysms or angiomas. Two additional patients developed intraoperative seizures, cardiac arrhythmia, and hypotension. The head CT image in 1 of these 2 patients had intracranial air entrapment.In the second part, epidural pressure measurements in 12 patients who underwent uneventful routine lumbar interlaminar decompression for L4-L5 and L5-S1 disc herniation showed an average epidural pressure of 24.5 mm Hg.In the third part, the online survey was accessed by 766 spine surgeons worldwide and had a response rate of 43.6%. Irrigation-related problems were reported by 38% of responding surgeons. Only 11.8% used irrigation pumps, with 90% running the pump above 40 mm Hg. Headaches (4.5%) and neck pain (4.9%) were observed by nearly a 10th (9.4%) of surgeons. Seizures in combination with headaches, neck and abdominal pain, soft tissue edema, and nerve root injury were reported by another 5 surgeons. One surgeon reported a delirious patient. Another 14 surgeons thought that they had patients with neurological deficits ranging from nerve root injury to cauda equina syndrome related to irrigation fluid. Autonomic dysreflexia associated with hypertension was attributed by 19 of the 244 responding surgeons to the noxious stimulus of escaped irrigation fluid that migrated from the decompression site in the spinal canal. Two of these 19 surgeons reported 1 case associated with a recognized incidental durotomy and another with postoperative paralysis. Patients should be educated preoperatively about the risk of irrigated spinal endoscopy. Although rare, intracranial blood, hydrocephalus, headaches, neck pain, seizures, and more severe complications, including life-threatening autonomic dysreflexia with hypertension, may arise if irrigation fluid enters the spinal canal or the dural sac and migrates from the endoscopic site along the neural axis rostrally. Experienced endoscopic spine surgeons suspect a correlation between durotomy and irrigation-related extra- and intradural pressure equalization that could be problematic if associated with high volumes of irrigation fluid LEVEL OF EVIDENCE: 3.

Clinical Consequences of Incidental Durotomy during Full-Endoscopic Lumbar Decompression Surgery in Relation to Intraoperative Epidural Pressure Measurements

Background: Seizures, neurological deficits, bradycardia, and, in the worst cases, cardiac arrest may occur following incidental durotomy during routine lumbar endoscopy. Therefore, we set out to measure the intraoperative epidural pressure during lumbar endoscopic decompression surgery. Methods: We conducted a retrospective observational cohort study to obtain intraoperative epidural measurements with an epidural catheter-pressure transducer assembly through the spinal endoscope on 15 patients who underwent lumbar endoscopic decompression of symptomatic lumbar herniated discs and spinal stenosis. The endoscopic interlaminar technique was employed. Results: There were six (40.0%) female and nine (60.0%) male patients aged 49.0667 ± 11.31034, ranging from 36 to 72 years, with an average follow-up of 35.15 ± 12.48 months. Three of the fifteen patients had seizures with durotomy and one of these three had intracranial air on their postoperative brain CT. Another patient developed spinal headaches and diplopia on postoperative day one when her deteriorating neurological function was investigated with a brain computed tomography (CT) scan, showing an intraventricular hemorrhage consistent with a Fisher Grade IV subarachnoid hemorrhage. A CT angiogram did not show any abnormalities. Pressure recordings in the epidural space in nine patients ranged from 20 to 29 mm Hg with a mean of 24.33 mm Hg. Conclusion: Most incidental durotomies encountered during lumbar interlaminar endoscopy can be managed without formal repair and supportive care measures. The intradural spread of irrigation fluid and intraoperatively used drugs and air entrapment through an unrecognized durotomy should be suspected if patients deteriorate in the recovery room. Ascending paralysis may cause nausea, vomiting, upper and lower motor neuron symptoms, cranial nerve palsies, hypotension, bradycardia, and respiratory and cardiac arrest. The recovery team should be prepared to manage these complications.

Air bubble artifact: why postmortem brain MRI should always be combined with postmortem CT.

Forensic pathology increasingly uses postmortem magnetic resonance imaging (PMMRI), particularly in pediatric cases. It should be noted that each (sudden and unexpected) death of an infant or child should have a forensic approach as well. Current postmortem imaging protocols do not focus adequately on forensic queries. First, it is important to demonstrate or rule out bleeding, especially in the brain. Thus, when incorporating PMMRI, a blood sensitive sequence (T2* and/or susceptibility weighted imaging (SWI)) should always be included. Secondly, as intracranial air might mimic small focal intracerebral hemorrhages, PMMRI should be preceded by postmortem CT (PMCT) since air is easily recognizable on CT. This will be illustrated by a case of a deceased 3-week-old baby. Finally, note that postmortem scans will often be interpreted by clinical radiologists, sometimes with no specific training, which makes this case report relevant for a broader audience.

Comparison of EPI DWI and STEAM DWI in Early Postoperative MRI Controls After Resection of Tumors of the Central Nervous System

PurposeDiffusion-weighted imaging (DWI) is important for differentiating residual tumor and subacute infarctions in early postoperative magnetic resonance imaging (MRI) of central nervous system (CNS) tumors. In cases of pneumocephalus and especially in the presence of intraventricular trapped air, conventional echo-planar imaging (EPI) DWI is distorted by susceptibility artifacts. The performance and robustness of a newly developed DWI sequence using the stimulated echo acquisition mode (STEAM) was evaluated in patients after neurosurgical operations with early postoperative MRI.MethodsWe compared EPI and STEAM DWI of 43 patients who received 3‑Tesla MRI within 72 h after a neurosurgical operation between 1 October 2019 and 30 September 2021. We analyzed susceptibility artifacts originating from air and blood and whether these artifacts compromised the detection of ischemic changes after surgery. The DWI sequences were (i) visually rated and (ii) volumetrically analyzed.ResultsIn 28 of 43 patients, we found severe and diagnostically relevant artifacts in EPI DWI, but none in STEAM DWI. In these cases, in which artifacts were caused by intracranial air, they led to a worse detection of ischemic lesions and thus to a possible failed diagnosis or lack of judgment using EPI DWI. Additionally, volumetric analysis demonstrated a 14% smaller infarct volume detected with EPI DWI. No significant differences in visual rating and volumetric analysis were detected among the patients without severe artifacts.ConclusionThe newly developed version of STEAM DWI with highly undersampled radial encodings is superior to EPI DWI in patients with postoperative pneumocephalus.

Intracranial Air Absorption through Arachnoid Granulation: New Considerations from Transsphenoidal Surgery and Implications for Neurofluid Dynamics

Intracranial Air Absorption through Arachnoid Granulation: New Considerations from Transsphenoidal Surgery and Implications for Neurofluid Dynamics

Tension Pneumocephalus Caused by Ethmoidal Roof Fracture: Emergent Surgical Decompression.

Tension pneumocephalus is a neurosurgical emergency that occurs when air is trapped in the intracranial cavity, leading to brain compression and causing severe neurological symptoms such as decreases in motor function, sensory function, and consciousness. Most cases of pneumocephalus require conservative treatment; however, because of the possible fatal complications, rapid diagnosis and appropriate treatment are important. Here, we present the case of an 81-year-old male patient who had undergone head trauma three hours prior to being admitted to our emergency room (ER) because of mental cloudiness. The radiologic findings showed tension pneumocephalus caused by an ethmoidal roof fracture. Emergency reconstruction of the ethmoidal roof with craniotomy was performed to remove the intracranial air using normal saline irrigation. By sharing our experience with this case, we hope to provide an option for the treatment of such cases.

Comparison of dural puncture and dural incision in deep brain stimulation surgery: A simple but worthwhile technique modification.

The accuracy of the deep brain stimulation (DBS) electrode placement is influenced by a myriad of factors, among which pneumocephalus and loss of cerebrospinal fluid that occurs with dural opening during the surgery are considered most important. This study aimed to describe an effective method for decreasing pneumocephalus by comparing its clinical efficacy between the two different methods of opening the dura. We retrospectively compared two different methods of opening the dura in 108 patients who underwent bilateral DBS surgery in our center. The dural incision group comprised 125 hemispheres (58 bilateral and 9 unilateral) and the dural puncture group comprised 91 (41 bilateral and 9 unilateral). The volume of intracranial air, dural opening time, intraoperative microelectrode recordings (MERs), postoperative electrode displacement, clinical efficacy, and complications were examined. Spearman correlation analysis was employed to identify factors associated with the volume of intracranial air and postoperative electrode displacement. The volume of intracranial air was significantly lower (0.35 cm3 vs. 5.90 cm3) and dural opening time was significantly shorter (11s vs. 35s) in the dural puncture group. The volume of intracranial air positively correlated with dural opening time. During surgery, the sensorimotor area was longer (2.47 ± 1.36 mm vs. 1.92 ± 1.42 mm) and MERs were more stable (81.82% vs. 47.73%) in the dural puncture group. Length of the sensorimotor area correlated negatively with the volume of intracranial air. As intracranial air was absorbed after surgery, significant anterior, lateral, and ventral electrode displacement occurred; the differences between the two groups were significant (total electrode displacement, 1.0mm vs. 1.4mm). Electrode displacement correlated positively with the volume of intracranial air. Clinical efficacy was better in the dural puncture group than the dural incision group (52.37% ± 16.18% vs. 43.93% ± 24.50%), although the difference was not significant. Our data support the hypothesis that opening the dura via puncture rather than incision when performing DBS surgery reduces pneumocephalus, shortens dural opening time, enables longer sensorimotor area and more stable MERs, minimizes postoperative electrode displacement, and may permit a better clinical efficacy.

Pneumocephalus and headache following craniotomy during the immediate postoperative period

BackgroundPneumocephalus may be responsible for post-craniotomy headache but is easily overlooked in the clinical situation. In the present study, the relationship between the amount of intracranial air and post-craniotomy headache was investigated.MethodsA retrospective observational study was performed on 79 patients who underwent minimal invasive craniotomy for unruptured cerebral aneurysms. Those who had undergone previous neurosurgery, neurological deficit before and after surgery were excluded The amount of air in the cranial cavity was measured using brain computed tomography (CT) taken within 6 h after surgery. To measure the degree of pain due to intracranial air, daily and total analgesic administration amount were used as a pain index. Correlation between intracranial air volume and total consumption of analgesic during hospitalization was tested using Spearman rank correlation coefficients. Receiver operating characteristics (ROC) analysis was used to determine the amount of air associated with increased analgesic consumption over 72 h postoperatively.ResultsThe mean amount of intracranial air was 15.6 ± 9.1 mL. Total administration of parenteral and oral analgesics frequency were 6.5 ± 4.5, 13.2 ± 7.9 respectively. A statically significant correlation was observed between daily and total parenteral analgesic consumption after surgery and the amount of intracranial air at followed-up brain CT postoperatively within 24 h (r = 0.69, p < 0.001), within 48 h (r = 0.68, p < 0.001), and total duration after surgery (r = 0.84, p < 0.001). The optimal cut-off value of 12.14 mL of intracranial air predicts the use of parenteral analgesics over 72 h after surgery.ConclusionsPneumocephalus may be a causative factor for post-craniotomy pain and headache with surgical injuries.

Cranial defect and pneumocephalus are associated with significant postneurosurgical positional brain shift: evaluation using upright computed tomography

Only few studies have assessed brain shift caused by positional change. This study aimed to identify factors correlated with a large postneurosurgical positional brain shift (PBS). Sixty-seven patients who underwent neurosurgical procedures had upright computed tomography (CT) scan using settings similar to those of conventional supine CT. The presence of a clinically significant PBS, defined as a brain shift of ≥ 5 mm caused by positional change, was evaluated. The clinical and radiological findings were investigated to identify factors associated with a larger PBS. As a result, twenty-one patients had a clinically significant PBS. The univariate analysis showed that supratentorial lesion location, intra-axial lesion type, craniectomy procedure, and residual intracranial air were the predictors of PBS. Based on the multivariate analysis, craniectomy procedure (p < 0.001) and residual intracranial air volume (p = 0.004) were the predictors of PBS. In a sub-analysis of post-craniectomy patients, PBS was larger in patients with supratentorial craniectomy site and parenchymal brain injury. A large craniectomy area and long interval from craniectomy were correlated with the extent of PBS. In conclusion, patients who undergo craniectomy and those with residual intracranial air can present with a large PBS. In post-craniectomy patients, the predisposing factors of a large PBS are supratentorial craniectomy, presence of parenchymal injury, large skull defect area, and long interval from craniectomy. These findings can contribute to safe mobilization among postneurosurgical patients and the risk assessment of sinking skin flap syndrome.

Morbid Constellation of Osseous and Vascular Abnormalities in a Female Patient with Congenital Central Hypoventilation/Overgrowth Syndrome

Background: Congenital Central Hypoventilation Syndrome (CCHS), is a condition characterized by ventilatory impairment that results in arterial hypoxemia. Studies revealed that the vast majority of patients with CCHS are free from any associated pulmonary, cardiac or brainstem pathologies. Material and Methods: F.R is a 20 -year-old- Austrian-girl presented in my consultation seeking advice for her unpleasant clinical history. In her early life, seizures were the first serious clinical presentation. Followed later on with hypertension, bouts of respiratory dysfunction and impairment of consciousness. In 2019 she underwent surgical intervention to remove a 2 cm hamartoma (posterior upper aspect of the right thigh). Few years later, another hamartoma on the ventral side of the tongue has been identified as well. Early on, she received the diagnosis of Mediterranean fever syndrome and the geneticist encountered homozygosity to the MEFV M694V mutation as the reason behind the constellation of the current unpleasant symptomatology. Later on a presumptive diagnosis of Ehlers-Danlos syndrome-hypermobile type has been suggested in other Medical Institutions. We proceeded with our documentation via clinical and radiological phenotypic characterizations. Results: Clinical examination showed growth above the 97th percentile (overgrowth) with no specific facial dysmorphic features. She manifested generalized ligamentous hyper laxity. Her ligamentous hyperlaxity was compatible with 6 points out of 9 in correlation with Beighton scoring test. On the bases of skeletal survey; lateral skull radiograph showed features of mastoid and temporal bone characterized with extensive-pneumatization. Axial CT scan shows bilateral hyper-pneumatization of the temporal bones, demonstrating expansion of aerial spaces with loss of the bony trabeculae and thinning of the mastoid bone. Mastoid cells appear to be in communication with a large intracranial epidural air cavity in the temporal and parietal regions. Reformatted CT scan of temporal bone, through coronal and axial images, at the level of the cavum tympani and the mastoid, showed a defect in the right tegmen appeared as cloudy/ opaque lesions around the cavum and the surrounding air cells. Contrast- enhanced computed CT angiography of the cervical and cerebral vasculature showed unusual malalignment and spiral twisting along several vascular segments resulted in the mal-development of basilar artery stenosis without atherosclerosis. The current patient manifested overgrowth syndromic entity with a constellation of osseous and vascular abnormalities resulted in a clinical course of congenital central hypoventilation syndrome. Conclusion: The etiology behind the extension of pneumatization has most likely occurred because of defective ossification of the occipito-mastoid synchondrosis . The reason behind the extension of pneumatization into the occipital and parietal bone is probably due to incomplete closure of the occipito-mastoid synchondrosis, lambdoid and sagittal sutures, which usually close in early adulthood and later, even at the age of thirties. In our patient, we postulate that the history of multiple hamartomas and abnormal vascular phenotype in conjunction with extensive hyper-pneumatization of the skull were the main etiology behind her unpleasant course of her devastating ailment regardless the genetic results. Our impression is neither Mediterranean fever syndrome nor Ehlers-Danlos syndrome seem compatible with her current constellation of osseous and vascular abnormalities. The overall clinical and imaging findings are highly likely in connection with either one of the different types of overgrowth syndromes or might be a novel syndromic association. We believe that congenital central hypoventilation is a symptom complex rather than a diagnostic entity.

Position-dependent pressure pneumocephalus after transsphenoidal surgery: illustrative case.

BACKGROUNDIntracranial air may become trapped inside the cranial vault after cranial surgery, causing tension pneumocephalus with a variety of possible neurological symptoms. The authors reported a unique case in which position-dependent tension pneumocephalus developed after standard pituitary adenoma resection, causing severe intermittent visual symptoms.OBSERVATIONSA tiny hole in the sellar floor after transsphenoidal surgery created a valve mechanism, allowing pressurized air accumulation inside the tumor capsule that periodically compressed the optic chiasm. This caused acute visual field defects only when the patient was in an upright position. Symptoms resolved when the patient lay down because pressurized air was allowed to escape from the cranial vault and compression of the optic chiasm was relieved. This phenomenon was verified with consecutive magnetic resonance imaging sequences demonstrating the relaxation of suprasellar space, after the intracranial air had escaped in a horizontal imaging position.LESSONSImperfect sealing of the sellar floor after transsphenoidal surgery is not uncommon. Even a tiny defect may in rare cases work in a valve-like manner, leading to intermittent air accumulation in the suprasellar space and causing corresponding visual symptoms. Pressure pneumocephalus inside an empty tumor capsule should be kept in mind as a possible rare complication after transsphenoidal surgery.

Detection of Cerebrospinal Fluid Leaks Using the Endoscopic Fluorescein Test in the Postoperative Period following Pituitary and Ventral Skull Base Surgery.

Objective Diagnosis of cerebrospinal fluid (CSF) leaks is sometimes challenging in the postoperative period following pituitary and ventral skull base surgery. Intrathecal fluorescein (ITF) may be useful in this setting. Design Retrospective chart review. Setting Tertiary care center. Methods and Participants All patients who underwent pituitary and ventral skull base surgery performed by a single rhinologist between January 2017 and March 2020 were included. There were 103 patients identified. Eighteen patients received 20 ITF injections due to clinical suspicion for CSF leak during the postoperative period without florid CSF rhinorrhea on clinical exam. Computed tomography scans with new or increasing intracranial air and intraoperative findings were used to confirm CSF leaks. Clinical courses were reviewed for at least 6 months after initial concern for leak as the final determinate of CSF leak. Main Outcome Measures Specificity and safety of ITF. Results Eleven (61%) ITF patients were female and 7 (39%) were male. Average patient age was 52.50 ± 11.89. There were six patients with confirmed postoperative CSF leaks, 3 of whom had evaluations with ITF. ITF use resulted in 2 true positives, 1 false negative, 17 true negatives, and 0 false positives. ITF sensitivity was 67%, specificity was 100%, and positive and negative predictive values were 100 and 94.4%, respectively. There were no adverse effects from ITF use. Conclusions Existing modalities for detecting postoperative CSF leaks suffer from suboptimal sensitivity and specificity, delayed result reporting, or limited availability. ITF represents a specific and safe test with potential utility in the postoperative setting.

Evaluating the Effectiveness of Minimally Invasive Surgery Using External Ventricular Drainage Systems in Draining Chronic Subdural Hematomas.

To show the effectiveness of minimally invasive surgery with external ventricular drainage systems (EVDS) in the treatment of chronic subdural hematomas by comparing with it with classic surgery with closed drainage system (CDS) with intracranial hematoma volume measurements and predict infection risks by comparing two different surgeries with each other with intracranial air volume measurements. From 2014 to 2020, the data of 28 patients with chronic subdural hematoma who underwent surgeries two large burr holes, saline irrigation, and CDS or one small burr hole, no saline irrigation, and EVDS were retrospectively who had preoperative computed tomography (CT) postoperative 1st-3rd day CT, and postoperative 7th-10th day CT were included in the study. Pre- and postoperative subdural liquid collection volumes and postoperative intracranial air volumes were measured using Sectra Medical Workstation. Results were compared between these two groups. There were no significant differences in the preoperative and 7th-10th day liquid volumes between these two groups (p > 0.05). There were significant differences in the postoperative 1st-3rd day air volume between these two groups (p < 0.001). The statistical results showed that surgeries with EVDS are as effective as surgeries with CDS in draining chronic subdural hematomas. We also determined that the intracranial air volume is significantly less in surgeries with EVDS. For this reason, we believe that EVDS can reduce the risk of postoperative infection.

Low Consciousness in a Patient with Venous Air Embolism Introduced via Peripheral Vascular Cannulation.

IntroductionVenous air embolism is rarely seen, can be fatal and is associated mostly with large central venous catheters and mechanical ventilation. Some cases due to peripheral intravenous access have also been reported.Case DescriptionWe present a case of intracranial venous air embolism most likely secondary to peripheral cannulation. On admission, the patient was drowsy with a suddenly deteriorating Glasgow coma scale score. This case emphasizes cautious cannula insertion and close monitoring of the patient in the event of complications.ConclusionIntravenous cannulation is common but care should be taken to avoid catastrophic complications. Consider air embolism as the differential diagnosis if a patient has a low level of consciousness after an intravenous cannula is inserted.LEARNING POINTSA reduced level of consciousness in a patient should be quickly recognised and the differential diagnosis of air embolism considered.Peripheral vascular cannulation should be carefully monitored.High-flow oxygen and efficient monitoring of the patient are required.