The membranes were fixed after 3, 6, or 24 h of incubation.

<p>Fewer morphological changes are seen in the control (left panels) or ACF groups (center panels), whereas the cytoplasm of constituent cells shrank and the nuclei of most infiltrated cells are pyknotic and deformed (round) in the NS group (right panels). The former alteration is the most noticeable in fibroblasts (green arrows) and the latter in lymphocytes (arrowheads).</p

Composition of solutions used in neurosurgery.

<p>Abbreviations: D5W: 5% dextrose solution, NS: Normal saline, LR: Lactated Ringer's solution, ACF: Artificial cerebrospinal fluid.</p

Factors related to recurrence: univariate analyses (t, U, χ², and Fisher's exact tests) and log-rank tests.

<p>Values are the mean ± SD when appropriate. Significant values are featured with bold font. Four PT-INR values from the non-recurrent group and 1 PT-INR value from the recurrent group were missing and were excluded from analysis. Abbreviations: Rec: Recurrence, GCS: Glasgow Coma Score, mRS: Modified Rankin scale, CT: Computed tomography, Hyper: Hyperdense, Iso: Isodense, Hypo: Hypodense, Lay: Layered, Grad: Gradation, Sep: Separated, Trab: Trabecular, PT-INR: International normalized ratio of prothrombin time, NS: Normal saline, ACF: Artificial cerebrospinal fluid, POD: Postoperative day.</p

Multivariate analyses of chronic subdural hematoma recurrence^a.

<p>Significant values are featured with bold font. Abbreviations: OR: Odds ratio, CI: Confidence interval, ACF: Artificial cerebrospinal fluid.</p

Cumulative recurrence rate of chronic subdural hematoma after surgery.

<p>The difference between the normal saline (NS) group and the artificial cerebrospinal fluid (ACF) group is statistically significant (<i>P</i> = .027, log-rank test).</p

Cross sections of the hematoma outer membranes fixed immediately after surgery (Control, left panels) or after 24 h of incubation with artificial cerebrospinal fluid (ACF, center panels) or normal saline (NS, right panels).

<p>The insets are higher magnifications of the perivascular area. Inflammatory cells, including lymphocytes (orange arrowheads) and eosinophils (yellow arrows), are mostly located in the loose stroma of the hematoma membrane in the NS group, whereas they are confined in the capillary lumen, in the control and ACF groups. Hematoxylin–eosin stain, Burr = 25 µm.</p