Estimating postoperative skull defect volume from CT images using the ABC method

Analysis of Factors Affecting Good Neovascularization After Indirect Bypass Surgery: A Two-center Retrospective Study

OBJECTIVE

The purpose of this study was to analyze factors affecting good neovascularization after indirect bypass surgery.

METHODS

From August 2000 to July 2020, postoperative image results and medical records of 132 patients (159 hemispheres) who underwent EDAS of indirect bypass surgery at two institutions were reviewed retrospectively. Based on DSA results, angiogenesis after indirect bypass was divided into "good" or "poor" according to the Matsushima criteria. STA flap length affecting GPN were analyzed in the entire group (n = 159) and a MMD group (n = 134).

RESULTS

In the entire group, GPN after EDAS was observed in 94 (59.1%) hemispheres. Age, MMD, hypertension, and bone flap size were identified as significant factors in univariate analysis. Also, in the MMD group, 86 (64.2%) hemispheres showed GPN. Hypertension and bone flap size were significant factors in both univariate and multivariate analyses. Cutoff values of bone flap size and GPN were 47.91 cm2 in the entire group and the MMD group.

CONCLUSIONS

In all patients who received EDAS, good postoperative neovascularization was significant in those with a young age, MMD, without hypertension, and large bone flap size. No hypertension and large bone flap size were meaningful factors in the MMD group. AUROC showed that an appropriate bone flap size was 47.91 cm2. However, a further controlled prospective study is needed.

Surgical application of endoscopic-assisted minimally-invasive neurosurgery to traumatic brain injury: Case series and review of literature

BACKGROUND/PURPOSE

Adequate decompression is the primary goal during surgical management of patients with traumatic brain injury (TBI). Therefore, it may seem counterintuitive to use minimally-invasive strategies to treat these patients. However, recent studies show that endoscopic-assisted minimally-invasive neurosurgery (MIN) can provide both adequate decompression (which is critical for preserving viable brain tissue) and maximize neurological recovery for patients with TBI. Hence, we reviewed the pertinent literature and shared our experiences on the use of MIN.

METHODS

This was a retrospective multi-center study. We collected data of 22 TBI patients receiving endoscopic-assisted MIN within 72 hours after the onset, with Glasgow Coma Scale (GCS) scores of 6-14 and whose hemorrhage volume ranging from 30 to 70 mL.

RESULTS

We have applied MIN techniques to a group of 22 patients with traumatic ICH (TICH), epidural hematoma (EDH), and subdural hematoma (SDH). The mean pre-operative GCS score was 7.5 (median 7), and mean hemorrhage volume was 57.14 cm³ Surgery time was shortened with MIN approaches to a mean of 59.6 min. At 6-month follow-up, the mean GCS score had improved to 12.3 (median 15). By preserving more normal brain tissue, MIN for patients with TBI can result in beneficial effects on recoveries and neurological outcomes.

CONCLUSION

Endoscopic-assisted MIN in TBI is safe and effective in a carefully selected group of patients.

Direct Consequences of Cranioplasty to the Brain: Intracranial Pressure Study

ABSTRACT

Intracranial pressure (ICP) is a crucial factor that we need to take into account in all major pathophysiological changes of the brain after decompressive craniectomy (DC) and cranioplasty (CP). The purpose of our study was to check ICP values before and after cranioplasty and its relation to various parameters (imaging, demographics, time of cranioplasty, and type of graft) as well as its possible relation to postsurgical complications. The authors performed a prospective study in which they selected as participants adults who had undergone unilateral frontotemporoparietal DC and were planned to have cranioplasty. Intracranial pressure was measured with optical fiber sensor in the epidural space and did not affect cranioplasty in any way.Twenty-five patients met the criteria. The mean vcICP (value change of ICP) was 1.2 mm Hg, the mean ΔICP (absolute value change of the ICP) was 2.24 mm Hg and in the majority of cases there was an increase in ICP. The authors found 3 statistically significant correlations: between gender and ΔICP, Δtime (time between DC and CP) and vcICP, and pre-ICP and ±ICP (quantitative change of the ICP).Μale patients tend to develop larger changes of ICP values during CP. As the time between the 2 procedures (DC and CP) gets longer, the vcICP is decreased. However, after certain time it shows a tendency to remain around zero. Lower pre-ICP values (close to or below zero) are more possible to increase after bone flap placement. It seems that the brain tends to restore its pre-DC conditions after CP by taking near-to-normal ICP values.

Post-Cranioplasty Complications: Lessons From a Prospective Study Assessing Risk Factors

ABSTRACT

Complication rate related with cranioplasty is described as very high in most of relevant studies. The aim of our study was to try to identify possible factors, that could predict complications following cranioplasty. The authors hypothesized that some physical characteristics on the preoperative brain computed tomography (CT) scan can be predictive for complications.The authors carried out a prospective observational study. All patients were adults after decompressive craniectomy, planned for cranioplasty and had a brain CT scan the day before cranioplasty. Our data pool included demographics, reason of craniectomy, various radiological parameters, the time of cranioplasty after craniectomy, the type of cranioplasty bone flap, and the complications.Twenty-five patients were included in the study. The authors identified statistically significant correlation between time of cranioplasty after craniectomy and the complications, as well as between the type of cranioplasty implant and the complications. There was statistically significant correlation between complications and the distance of the free brain surface from the level of the largest skull defect dimension - free brain surface deformity (FBSD). Moreover, the correlation between FBSD and the time of cranioplasty was statistically significant.It seems that for adult patients with unilateral DC the shorter time interval between craniectomy and cranioplasty lowers the risk for complications. The risk seems to be decreased further, by using autologous bone flap. Low values of the FBSD increase the risk for complications. This risk factor can be avoided, by shortening the time between craniectomy and cranioplasty.

Estimation of the Craniectomy Surface Area by Using Postoperative Images

Decompressive craniectomy (DC) is a neurosurgical procedure performed to relieve the intracranial pressure engendered by brain swelling. However, no easy and accurate method exists for determining the craniectomy surface area. In this study, we implemented and compared three methods of estimating the craniectomy surface area for evaluating the decompressive effort. We collected 118 sets of preoperative and postoperative brain computed tomography images from patients who underwent craniectomy procedures between April 2009 and April 2011. The surface area associated with each craniectomy was estimated using the marching cube and quasi-Monte Carlo methods. The surface area was also estimated using a simple AC method, in which the area is calculated by multiplying the craniectomy length (A) by its height (C). The estimated surface area ranged from 9.46 to 205.32 cm², with a median of 134.80 cm². The root-mean-square deviation (RMSD) between the marching cube and quasi-Monte Carlo methods was 7.53 cm². Furthermore, the RMSD was 14.45 cm² between the marching cube and AC methods and 12.70 cm² between the quasi-Monte Carlo and AC methods. Paired t-tests indicated no statistically significant difference between these methods. The marching cube and quasi-Monte Carlo methods yield similar results. The results calculated using the AC method are also clinically acceptable for estimating the DC surface area. Our results can facilitate additional studies on the association of decompressive effort with the effect of craniectomy.

Brain Midline Shift Measurement and Its Automation: A Review of Techniques and Algorithms

Midline shift (MLS) of the brain is an important feature that can be measured using various imaging modalities including X-ray, ultrasound, computed tomography, and magnetic resonance imaging. Shift of midline intracranial structures helps diagnosing intracranial lesions, especially traumatic brain injury, stroke, brain tumor, and abscess. Being a sign of increased intracranial pressure, MLS is also an indicator of reduced brain perfusion caused by an intracranial mass or mass effect. We review studies that used the MLS to predict outcomes of patients with intracranial mass. In some studies, the MLS was also correlated to clinical features. Automated MLS measurement algorithms have significant potentials for assisting human experts in evaluating brain images. In symmetry-based algorithms, the deformed midline is detected and its distance from the ideal midline taken as the MLS. In landmark-based ones, MLS was measured following identification of specific anatomical landmarks. To validate these algorithms, measurements using these algorithms were compared to MLS measurements made by human experts. In addition to measuring the MLS on a given imaging study, there were newer applications of MLS that included comparing multiple MLS measurement before and after treatment and developing additional features to indicate mass effect. Suggestions for future research are provided.