Shu-Shya Hseu

Heavily T2-weighted MR myelography vs CT myelography in spontaneous intracranial hypotension

Objective: To assess the diagnostic accuracy of heavily T2-weighted magnetic resonance myelography (MRM) in patients with spontaneous intracranial hypotension (SIH). Methods: Patients with SIH were recruited prospectively, and first underwent MRM and then computed tomographic myelography (CTM). The results of MRM were validated with the gold standard, CTM, focusing on 1) CSF leaks along the nerve roots, 2) epidural CSF collections, and 3) high-cervical (C1–3) retrospinal CSF collections. Comparisons of these 3 findings between the 2 studies were made by κ statistics and agreement rates. Targeted epidural blood patches (EBPs) were placed at the levels of CSF leaks if supportive treatment failed. Results: Nineteen patients (6 men and 13 women, mean age 37.9 ± 8.6 years) with SIH completed the study. MRM did not differ from CTM in the detection rates of CSF leaks along the nerve roots (84% vs 74%, p = 0.23), high-cervical retrospinal CSF collections (32% vs 16%, p = 0.13), and epidural CSF collections (89% vs 79%, p = 0.20). MRM demonstrated more spinal levels of CSF leaks (2.2 ± 1.7 vs 1.5 ± 1.5, p = 0.011) and epidural collections (12.2 ± 5.9 vs 7.1 ± 5.8, p < 0.001) than CTM. The overall level-by-level concordance was substantial for CSF leaks along the nerve roots (C1–L3) (κ = 0.71, p < 0.001, agreement = 95%) and high-cervical retrospinal CSF collections (C1–3) (κ = 0.73, p < 0.001, agreement = 92%), and moderate for epidural CSF collections (C1–L3) (κ = 0.47, p < 0.001, agreement = 72%). Ten of the 14 patients (71%) receiving targeted EBPs experienced sustained symptomatic relief after a single attempt. Conclusions: Heavily T2-weighted magnetic resonance myelography was accurate in localizing CSF leaks for patients with spontaneous intracranial hypotension. This noninvasive technique may be an alternative to computed tomographic myelography before targeted epidural blood patches.

Oral clonidine premedication preserves heart rate variability for patients undergoing larparoscopic cholecystectomy.

Background: Clonidine has been shown to reduce perioperative circulatory instability. This postoperative analgesic effect of clonidine was also known in previous studies. The aim of the study was to investigate the clinical efficiency of oral clonidine premedication in anesthesia and analgesia in patients undergoing laparoscopic cholecystectomy.

Time‐varying spectral analysis revealing differential effects of sevoflurane anaesthesia: non‐rhythmic‐to‐rhythmic ratio

Heart rate variability (HRV) may reflect various physiological dynamics. In particular, variation of R‐R peak interval (RRI) of electrocardiography appears regularly oscillatory in deeper levels of anaesthesia and less regular in lighter levels of anaesthesia. We proposed a new index, non‐rhythmic‐to‐rhythmic ratio (NRR), to quantify this feature and investigated its potential to estimate depth of anaesthesia.

The Timing of MRI Determines the Presence or Absence of Diffuse Pachymeningeal Enhancement in Patients with Spontaneous Intracranial Hypotension

The timing and clinical relevance of diffuse pachymeningeal enhancement (DPE) in the magnetic resonance imaging (MRI) examination of patients with spontaneous intracranial hypotension (SIH) remain undetermined. We reviewed 53 consecutive SIH patients (30 F/23 M, mean age of onset 41.7 ± 11.3 years) in a tertiary hospital. Thirteen (24.5%) patients did not have DPE on their initial cranial MRIs. They had significantly shorter latency between the time of MRI examinations and the time of headache onset compared with those with DPE (6.5 ± 4.4 vs. 20.4 ± 16.3 days, t-test, P < 0.001). Eight of these 13 patients received a follow-up MRI (mean duration 30.3 ± 16.6 days, range 6-59 days) and six of them revealed DPE. Among patients with DPE, the enhancement disappeared as early as 25 days after headache onset. The outcome did not differ between patients with and without DPE. The presence of DPE was associated with the timing of the MRI examination.

Cerebrospinal fluid leakage and headache after lumbar puncture: a prospective non-invasive imaging study

The spatial distribution and clinical correlation of cerebrospinal fluid leakage after lumbar puncture have not been determined. Adult in-patients receiving diagnostic lumbar punctures were recruited prospectively. Whole-spine heavily T2-weighted magnetic resonance myelography was carried out to characterize post-lumbar puncture spinal cerebrospinal fluid leakages. Maximum rostral migration was defined as the distance between the most rostral spinal segment with cerebrospinal fluid leakage and the level of lumbar puncture. Eighty patients (51 female/29 male, mean age 49.4 ± 13.3 years) completed the study, including 23 (28.8%) with post-dural puncture headache. Overall, 63.6% of periradicular leaks and 46.9% of epidural collections were within three vertebral segments of the level of lumbar puncture (T12-S1). Post-dural puncture headache was associated with more extensive and more rostral distributions of periradicular leaks (length 3.0 ± 2.5 versus 0.9 ± 1.9 segments, P = 0.001; maximum rostral migration 4.3 ± 4.7 versus 0.8 ± 1.7 segments, P = 0.002) and epidural collections (length 5.3 ± 6.1 versus 1.0 ± 2.1 segments, P = 0.003; maximum rostral migration 4.7 ± 6.7 versus 0.9 ± 2.4 segments, P = 0.015). In conclusion, post-dural puncture headache was associated with more extensive and more rostral distributions of periradicular leaks and epidural collections. Further, visualization of periradicular leaks was not restricted to the level of dural defect, although two-thirds remained within the neighbouring segments.

Factors predicting response to the first epidural blood patch in spontaneous intracranial hypotension.

Spontaneous intracranial hypotension results from cerebrospinal fluid leakage. Currently, the treatment of choice for spontaneous intracranial hypotension is the epidural blood patch, which has a variable response rate and no clear outcome predictors. This study aimed to identify predictors for response rate of a first targeted epidural blood patch in patients with spontaneous intracranial hypotension. We reviewed cases of patients with spontaneous intracranial hypotension who received targeted epidural blood patch at our hospital between 1 January 2007 and 1 July 2014. The outcome measure was first epidural blood patch response. We analysed demographics, clinical manifestations, neuroimaging findings (non-contrast heavily T2-weighted magnetic resonance myelography and brain magnetic resonance imaging), and blood volume as potential outcome predictors. Significant predictors were tested and a decision tree was used to construct a predictive model. In total, 150 patients with spontaneous intracranial hypotension were included for final analyses. Their overall first targeted epidural blood patch response rate was 58.7%. Among patients with a greater injected blood volume (≥22.5 versus <22.5 ml), the response rate was higher (67.9% versus 47.0%, P = 0.01). In brain and spinal magnetic resonance imaging studies, significant predictors included anterior epidural cerebrospinal fluid collection length (<8 versus ≥8 segments; 72.5% versus 37.3%, odds ratio = 4.4, 95% confidence interval: 2.2–8.9, P < 0.001) and midbrain-pons angle (≥40° versus <40°; 71.3% versus 37.5%, odds ratio = 4.1, 95% confidence interval 2.1–8.3, P < 0.001). Decision tree analyses showed that patients with anterior epidural CSF collection involving <8 segments and an injected blood volume ≥22.5 ml had an 80.0% response rate. Patients with anterior epidural cerebrospinal fluid collection involving ≥8 segments and a midbrain-pons angle <40° had a 21.2% response rate. These three variables predicted first epidural blood patch response in 71.3% of patients. Brain and spinal neuroimaging findings and epidural blood patch blood volume can be used to predict targeted first epidural blood patch response in patients with spontaneous intracranial hypotension.

Analyzing autonomic activity in electrocardiography about general anesthesia by spectrogram with multitaper time-frequency reassignment

Autonomic nerve activities in human body under general anesthesia are dynamic and diverse. Respiratory sinus arrhythmia is associated with depth of anesthesia, which exists in the high-frequency region of RRI (beat-to-beat R-peak interval) spectrum. Analyzing RRI variation in electrocardiography by classical power spectrum is insufficient because of the lack of temporal resolution. To better understand autonomic activity during anesthesia, we used spectrogram of RRI to extract its instantaneous information. For improving visual resolution, we choose a newly developed technique, multitaper time-frequency reassignment (MTFR), to estimate spectrograms. The technique provides time-varying spectrogram for RRI with good performance in time-frequency resolution and low fluctuation. Real-life cases are used to demonstrate the variety of autonomic activity presented clearly by the MTFR spectrogram, compared with Gabor spectrogram. Their implications in depth of anesthesia are discussed.

Treatment and prognosis of subdural hematoma in patients with spontaneous intracranial hypotension

Objective The objective of this article is to elucidate the outcome, prognostic predictors and timing of surgical intervention for subdural hematoma (SDH) in patients with spontaneous intracranial hypotension (SIH). Methods Patients with SDH were identified retrospectively from 227 consecutive SIH patients. Data were collected on demographics, clinical courses, neuroimaging findings, and treatment of SDH, which was later divided into conservative treatment, epidural blood patches (EBP), and surgical intervention. Poor outcome was defined as severe neurological sequelae or death. Results Forty-five patients (20%) with SDH (mean maximal thickness 11.9 ± 6.2 mm) were recruited. All 15 patients with SDH <10 mm achieved good outcomes by either conservative treatment or EBP. Of 30 patients with SDH ≥10 mm, patients with uncal herniation (n = 3) had poor outcomes, even after emergent surgical evacuation (n = 2), compared to those without (n = 27) (100% vs. 0%, p < 0.001). Fourteen patients underwent surgical evacuation, resulting in good outcomes in all 12 who received early intervention and poor outcomes in the remaining two who received delayed intervention after Glasgow Coma Scale (GCS) score ≤8 (100% vs. 0%, p = 0.01). Conclusions Uncal herniation results in poor outcomes in patients with SIH complicated with SDH. In individuals with SDH ≥10 mm and decreased GCS scores, early surgical evacuation might prevent uncal herniation.

Bilateral Tension Pneumothorax and Tension Pneumoperitoneum Secondary to Tracheal Tear in a Patient With Relapsing Polychondritis

Relapsing polychondritis (RP) is a rare disease that is characterized by recurrent inflammation and destruction of cartilage and connective tissues. RP can have significant airway pathology that may require procedures to maintain airway patency and thus may have serious implications for anesthesiologists. Anesthesiologists must be prepared to deal with the possible complications that may occur during airway manipulation in patients with RP. Here, we present a case of life-threatening bilateral tension pneumothorax and tension pneumoperitoneum that developed after a tracheal tear during Montgomery T-tube insertion in a patient with tracheal stenosis due to RP. Correct diagnosis was delayed due to a misdiagnosis of airway obstruction. As a result, we emphasize that bilateral tension pneumothorax should be considered during refractory cardiac arrest in patients with increased airway pressure. A high index of suspicion and adequate management are mandatory for patients to survive these life-threatening complications.

Spontaneous Intracranial Hypotension Treated by Epidural Blood Patches

We present a case of spontaneous intracranial hypotension (SIH) diagnosed from the clinical symptoms and magnetic resonance imaging brain scans. After failure of conservative treatment, and lack of identification of the cerebrospinal fluid leak site, the headache was managed successfully and simply with two applications of an epidural blood patch (EBP). The strategy of our management for the patient was as follows: (1) application of an EBP to the lumbar epidural space initially and manipulating it into the proximity of the possible leak site; (2) a greater volume of autologous blood was injected at the second attempt of EBP; and (3) the patient was required to lie flat for at least 2 hours after the procedure. Better management of SIH is still developing. Traditionally, SIH is initially managed by conservative treatment. However, recent studies have shown that the success rate in arresting SIH after weeks or months of conservative treatment is not quite satisfactory. Hence, the EBP has proven to be more effective in treating SIH patients. Early EBP application may offer immediate relief of clinical symptoms. The role of the EBP in treating SIH patients should have greater emphasis and its application is worth recommendation.