Use of autologous scapula for cranioplasty: cadaveric feasibility study

INTRODUCTION: Replacement sources for calvarial defects include synthetic materials, donor grafts, and autologous bones such as ribs or split-thickness calvarial cranioplasty. When these sources are not available or are inadequate, other structures or sites would be desirable. However, and to our knowledge, the scapula has not been explored as a potential source for calvarial reconstruction. Therefore, the following study was performed to verify the utility of this bone for cranioplasty. MATERIALS AND METHODS: Six adult (mean age 71 years) cadavers (four formalin-fixed and two fresh specimens) were used in this study. In the prone position, an incision was made over the midpart of the infraspinous fossa. Soft tissues were then removed from the anterior and posterior aspects of the scapula in this region avoiding the glenohumeral articulation superiorly. Previously made cranial defects were then filled using available scapula as a bony replacement. RESULTS: An average of 9 x 12 x 7 cm of scapula was available for harvest inferior to the glenohumeral joint. Lateral and medial borders of the scapula were found to have a mean thickness of 9 mm. No obvious injury to surrounding vessels or nerves was found using this procedure and good coverage of calvarial defects was afforded by this bony replacement. CONCLUSIONS: Such a bony substitute as autologous scapula might be of utility when other replacements are not available or are of a limited size. Examples of such a use would include patients in whom a hemispheric bone flap is lost. Following clinical confirmation, the neurosurgeon may wish to consider the scapula as an alternative site for bone harvest for cranioplasty as this was a feasible technique in the cadaver.     

Three‐dimensional morphometry of the A2 segment of the anterior cerebral artery with neurosurgical relevance

Most prior morphometry data regarding the A2 segment of the anterior cerebral artery (ACA) have been based on cadaveric measurements. With newer imaging modalities, surgical techniques, and minimally invasive procedures, new standards for the anatomy of this vessel are necessary. A novel computer‐based data system was used to analyze the three‐dimensional (3D) morphometry of 230 A2 segments. In addition, tortuosity (TI) and deviation indices (DI) for this segment were calculated. The mean internal diameter of the A2 segment was 1.86 mm, and segments tended to be larger in men and on left sides. A2 segments were asymmetrical in 43%, and this was more common in women. Lengths tended to be greater on right sides and in men. Volumes were greater in men and increased with age, which was statistically significant. These gender differences were found to be statistically significant (P < 0.05), for both volume and diameter. TI was equal among sides, but DI was more often greater on right sides. The correlation coefficient ratio for length and DI was statistically significant. It is important to understand various 3D morphometrical differences particularly between genders. By constructing blood flow simulation models and during revascularization procedures, surgeons are able to gain a better understanding of each patient's vascular anatomy. These additional 3D data regarding the anatomy of the postcommunicating parts of the ACA may be useful to the neurosurgeon and interventional neuroradiologist. These data may assist with an earlier diagnosis of pathologies affecting the 3D morphology of the ACA. Clin. Anat. 23:759–769, 2010. © 2010 Wiley‐Liss, Inc.     

Endothelin system and atrial fibrillation post-cardiac surgery

Objective We investigated the relation between the endothelin system and atrial fibrillation. Background Endothelin has been implicated in the pathophysiology of atrial fibrillation, but the exact role of A- and B-receptors is unknown. Methods We obtained right atrial biopsies from patients in sinus rhythm and preserved left ventricular function, undergoing off-pump coronary artery bypass grafting. The expression of endothelin, A- and B-receptors was measured using real time reverse-transcribed polymerase chain reaction. Results We studied 52 patients (45 male, mean age 66 ± 1 years, mean ejection fraction 52 ± 1%). During a 5-day post-operative period, persistent atrial fibrillation occurred in 15 patients (28.8%). Endothelin mRNA expression was comparable in patients who subsequently developed atrial fibrillation and in those maintaining sinus rhythm. However, the former group displayed down-regulation of endothelin A- (by approximately 60%, p = 0.0059) and of B-receptors (by approximately 40%, p = 0.0084). The decreased endothelin A-receptor expression could predict atrial fibrillation occurrence (Wilks λ = 0.86, F = 6.16, p = 0.017). Conclusion Decreased endothelin A- and B-receptor expression is associated with atrial fibrillation after bypass surgery. Theofilos M. Kolettis and Zenon S. Kyriakides contributed equally to the study.     

The intriguing history of the human calvaria: sinister and religious

Introduction A review of the ancient world finds multiple documentations describing the use of the human calvaria as a drinking implement. Terminology This term, which is frequently and incorrectly called the “calvarium,” has a unique history among multiple cultures of the world. For example, the purported site of Jesus’ crucifixion “Calvary” is derived from this term calvaria. The present report explores the derivation, misuse, and history of the human calvaria.     

An automated skills assessment framework for laparoscopic training tasks

Background

Various sensors and methods are used for evaluating trainees' skills in laparoscopic procedures. These methods are usually task‐specific and involve high costs or advanced setups.

Methods

In this paper, we propose a novel manoeuver representation feature space (MRFS) constructed by tracking the vanishing points of the edges of the graspers on the video sequence frames, acquired by the standard box trainer camera. This study aims to provide task‐agnostic classification of trainees in experts and novices using a single MRFS over two basic laparoscopic tasks.

Results

The system achieves an average of 96% correct classification ratio (CCR) when no information on the performed task is available and >98% CCR when the task is known, outperforming a recently proposed video‐based technique by >13%.

Conclusions

Robustness, extensibility and accurate task‐agnostic classification between novices and experts is achieved by utilizing advanced computer vision techniques and derived features from a novel MRFS.     

Surgical relevance of the lateral costotransverse ligament in relation to the dorsal root ganglion

The lateral costotransverse ligament, a short band that stabilizes the costovertebral joint, is found in close proximity to the dorsal root ganglion. This ligament is an important surgical landmark during tumor resections or nerve blocks in the paravertebral space. The purpose of this study was to quantitatively and qualitatively describe the morphology of the lateral costotransverse ligament and its relation to the dorsal root ganglion at all levels of the thoracic spine. The thoracic spines of eight embalmed cadavers were dissected bilaterally. The length, width, and thickness of the ligament were measured. The distance from the inferolateral aspect of the ligament to the lateral aspect of the dorsal root ganglion was also measured. Three bilateral groups of lateral costotransverse ligaments, top (on ribs 1–2), middle (on ribs 3–10), and bottom (on ribs 11–12), were compared based on anatomic distinctions between the costotransverse joints, which can influence ligament morphology. Among the three groups, the differences between the length, width, and thickness were not statistically significant. However, the distance from the lateral costotransverse ligament to the dorsal root ganglion differed significantly (P = 0.000), with the middle group having the longest distance, and the bottom group having the shortest distance. This finding can help clinicians and surgeons avoid iatrogenic injuries of neural structures during thoracic spine surgery, or when performing nerve blocks in the paravertebral space.     

Arterial variations around the atlas: a comprehensive review for avoiding neurosurgical complications

Introduction

Neurosurgical approaches often involve the atlas. Therefore, the arterial relationships and anatomical variations are of paramount importance to the neurosurgeon.

Methods

Using standard search engines, a literature review of arterial variants near the first cervical vertebra was performed.

Conclusions

Arterial variations around the atlas are surgically significant. Awareness of their existence and course may provide better pre-operative planning and surgical intervention, potentially leading to better clinical outcomes. Three-dimensional computed tomography angiography (3D CTA) is an important tool for identifying and diagnosing such abnormalities and should be used when such vascular anomalies are suspected.