Mathematical formulae to estimate chronic subdural haematoma volume. Flawed assumption regarding ellipsoid morphology

The validity of the simple methods of estimating chronic subdural hematoma volume

OBJECTIVES

It was reported that the XYZ/2 technique (using length, width and height of hematoma) is a simple and reliable method of estimation of chronic subdural hematoma volume. Two subtypes of techniques enable to adequately estimate, it is unclear which is more accurate. Computer-assisted volumetric analysis is widely considered the gold standard for CSDH volumetric analysis. It is important to consider the stability of analyses between examiners, because individual, decision-making differences may be relevant to the analysis, as hematoma margin and length are hand-operated. In this study, we investigated potential measurement biases of three neurosurgeons and analyzed the validity of the XYZ/2 technique by comparing it to the gold standard method.

METHOD

We retrospectively analyzed CT scans that indicated the need for an operation in 50 patients with CSDH in our department. Three neurosurgeons measured and calculated CSDH volumes independent of one another. We investigated potential measurement biases of three neurosurgeons and analyzed the validity of the XYZ/2 technique by comparing it to the gold standard method. The XYZ/2 technique includes the "maximal method" that uses the maximum length and maximum width of a slice to determine volume, and the "central method" that uses only the central slice to measure length and width.

RESULTS

ICCs for the gold standard, central method, and maximal method were 0.945, 0.916, and 0.844, respectively, all of which indicated excellent reliability. For all examiners, the differences in calculation from gold standard and central method were not statistically significant (P>0.05). The estimations of CSDH volume calculated by the maximal method were significantly greater than the estimates calculated by the gold standard (P<0.05).

CONCLUSIONS

This study proves that the XYZ/2 technique is a simple and reliable method of estimating CSDH volume. The "central method" in particular yielded similar results to that of the gold standard method.

Ultrasound-guided percutaneous endovenous laser treatment combined with sclerotherapy for the treatment of large intramuscular venous malformations

BACKGROUND

Among vascular anomalies, congenital venous malformations (VMs) are the most common lesions. Treatment of VMs is sometimes difficult or cumbersome, depending on their size and tissue involvement. Surgery may lead to invasive and mutilating excisions, often allowing only partial removal, with an increased risk of recurrence. Sclerotherapy is a mainstream technique, resulting in endothelium destruction, fibrosis and subsequent shrinkage of the vascular lesion, also with a risk of recurrence. However, this technique may not be efficient in cases of large and infiltrating VMs. Endovenous thermal ablation has been found to be more effective than sclerotherapy for transmural vascular destruction and has therefore been employed in the treatment of VMs.

METHODS

In this study we described a combined technique for the treatment of large intramuscular VMs in seven consecutive patients, associating endovenous laser ablation with sclerotherapy. The aim was to assess feasibility and safety of the procedure.

RESULTS

We reported a high immediate technical success, clinical and radiological improvement, with no complications.

CONCLUSIONS

The preliminary results presented herein show, that combining EVLA and sclerotherapy for the treatment of voluminous persistent intramuscular VM is safe and technically feasible. The combination of a wide direct intimal thermal damage with chemical sclerotherapy is the force of this approach. The small number of cases and the medium term follow up represent though a limitation.

Development of the Subdural Hematoma in the Elderly (SHE) score to predict mortality

OBJECTIVE

The purpose of this study was to describe the development of a novel prognostic score, the Subdural Hematoma in the Elderly (SHE) score. The SHE score is intended to predict 30-day mortality in elderly patients (those > 65 years of age) with an acute, chronic, or mixed-density subdural hematoma (SDH) after minor, or no, prior trauma.

METHODS

The authors used the Prognosis Research Strategy group methods to develop the clinical prediction model. The training data set included patients with acute, chronic, and mixed-density SDH. Based on multivariate analyses from a large data set, in addition to review of the extant literature, 3 components to the score were selected: age, admission Glasgow Coma Scale (GCS) score, and SDH volume. Patients are given 1 point if they are over 80 years old, 1 point for an admission GCS score of 5-12, 2 points for an admission GCS score of 3-4, and 1 point for SDH volume > 50 ml. The sum of points across all categories determines the SHE score.

RESULTS

The 30-day mortality rate steadily increased as the SHE score increased for all SDH acuities. For patients with an acute SDH, the 30-day mortality rate was 3.2% for SHE score of 0, and the rate increased to 13.1%, 32.7%, 95.7%, and 100% for SHE scores of 1, 2, 3, and 4, respectively. The model was most accurate for acute SDH (area under the curve [AUC] = 0.94), although it still performed well for chronic (AUC = 0.80) and mixed-density (AUC = 0.87) SDH.

CONCLUSIONS

The SHE score is a simple clinical grading scale that accurately stratifies patients' risk of mortality based on age, admission GCS score, and SDH volume. Use of the SHE score could improve counseling of patients and their families, allow for standardization of clinical treatment protocols, and facilitate clinical research studies in SDH.

Factors associated with the progression of conservatively managed acute traumatic subdural hemorrhage

PURPOSE

Traumatic subdural hemorrhage (SDH) is associated with high mortality, yet many patients are not managed surgically. We sought to understand what factors might be associated with SDH enlargement to contribute to the triage of these conservatively managed patients.

MATERIALS AND METHODS

A consecutive series of 117 patients admitted to our institution's level 1 trauma center for SDH between January 1, 2010 and December 31, 2010 were evaluated. Volumetric measurement of SDHs was performed on initial and follow-up head computed tomography (CT) scans with recording of initial midline shift and classification by location. Multimodel analysis quantified associations with change in SDH volume.

RESULTS

Systolic blood pressure, presence of subarachnoid hemorrhage, and initial SDH volume demonstrated positive associations with change in SDH volume, while initial midline shift and transfusion of platelets demonstrated negative associations. Initial convexity SDH volume demonstrated positive association with change in convexity SDH volume, while initial midline shift and transfusion of platelets demonstrated negative associations. Anticoagulant/antiplatelet use demonstrated positive association with change in tentorial SDH volume, while time between CT scans demonstrated negative association.

CONCLUSIONS

Platelet transfusion, anticoagulation, and hypertension have significant associations with expansion in non-surgical cases of SDH. Monitoring these factors may assist triaging these patients.

Membrane Surface Area to Volume Ratio in Chronic Subdural Hematomas: Critical Size and Potential Postoperative Target

BACKGROUND

It is unknown why some chronic subdural hematomas (CSDHs) grow and require surgery, whereas others spontaneously resolve. Although a relatively small CSDH volume (V) reduction may induce resolution, V percent reduction is often unreliable in predicting resolution. Although CSDHs evolve distinctive inner neomembranes and outer neomembranes (OMs), the OM likely dominates the dynamic growth-resorption equilibrium. If other factors remain constant, one previous hypothesis is that resorption could fail as the surface area (SA) to V ratio decreases when CSDHs exceed a critical size. We aimed to identify a critical size and an ideal target, which implies resolution without recurrence.

METHODS

Three-dimensional computed tomography CSDH SA to V ratios were obtained using computer software to compare CSDH SA to V between cases requiring surgery (surgical) and cases managed conservatively with spontaneous resolution (nonsurgical).

RESULTS

Data were obtained in 45 patients (surgical: n = 28; nonsurgical: n = 17). CSDH risk factors did not significantly differ between surgical and nonsurgical cases. Surgical V was 2.5× the nonsurgical V (119.9 ± 33.1 mL vs. 48.4 ± 27.4 mL, respectively; P < 0.0001). Surgical total SA was 1.4× nonsurgical SA (256.63 ± 70.65 cm² vs. 187.67 ± 77.72 cm², respectively; P = 0.004). Surgical total SA to V ratio was approximately one half that of nonsurgical SA to V ratio (2.14 ± 0.90 mL^-1 vs. 3.88±1.22 mL^-1, respectively; P < 0.0001). Surgical OM SA (SA_OM) was 120.63 ± 52 cm², and nonsurgical SA_OM was 94.10 ± 41 cm² (P < 0.0001). Nonsurgical SA_OM to V ratio was 1.94 mL^-1, whereas surgical SA_OM to V ratio was 1.005 mL^-1 (i.e., surgical SA_OM ≈ V).

CONCLUSIONS

Because surgical total SA to V ratio was ≈2:1, one neomembrane may indeed dominate the dynamic growth-resorption equilibrium. CSDH critical size therefore appears to be when SA_OM ≈ V, which is intuitive. Practically, subtotal CSDH evacuation which approximately doubles total SA to V ratio or SA_OM to V ratio implies CSDH resolution without recurrence. This could guide subdural drain removal timing, discharge, or transfer. Prospective validation studies are required.