Defining the Temporal and Occipital Lobes: Cadaveric Study with Application to Neurosurgery of the Inferior Brain

BACKGROUND

For surgical interventions, a precise understanding of the anatomical variations of the brain and defined anatomical landmarks to demarcate the regions of the temporal lobe is essential. Many anatomical studies have facilitated important surgical approaches to the temporobasal region. Because there is considerable sulcal variability, morphological analysis of the brain is imperative. The aim of this study was to define the boundaries of the temporal and occipital lobes and to define the variations in sulci and gyri in the inferior aspect.

METHODS

In 110 cerebral hemispheres variations were identified and the major landmarks of the gyral-sulcal pattern at the inferior aspect of the brain were defined.

RESULTS

The anatomy of the inferior aspect of the brain is defined in detail by morphological analysis of formalin-fixed hemispheres with a view to informing important surgical approaches.

CONCLUSIONS

Since the literature defines no clear separation between the temporal and occipital lobes, certain landmarks such as the preoccipital notch and a basal temporo-occipital line were suggested as ways of making the distinction. The parahippocampal ramus is a constant structure that can be used as a reliable landmark for the posterior end of the hippocampus.

Identification of Deep Cervical Fascial Layers During Anterior Cervical Spine Exposure

BACKGROUND

Anterior approaches to the cervical spine are among the most common exposures by which neurosurgeons and orthopedic surgeons access the prevertebral space and ultimately the cervical disk and vertebral bodies. There is a paucity of literature describing the microanatomic fascial planes of the neck with respect to anterior cervical approaches.

OBJECTIVE

To delineate the microanatomic connections of the cervical fascial planes pertinent to anterior cervical exposure.

METHODS

Using a cadaveric model, original illustrations, the Visible Human Project, and an original surgical video, we demonstrate a stepwise method for identifying the correct planes for anterior cervical exposure.

RESULTS

A step-by-step method for identifying the anterior cervical fascial planes intraoperatively is demonstrated.

CONCLUSION

A comprehensive understanding of anterior cervical microsurgical anatomy is vital for performing a methodical yet efficient approach to the prevertebral space while minimizing retraction and iatrogenic injury to the surrounding neurovascular structures.

The iliac pillar - Definition of an osseous fixation pathway for internal and external fixation

BACKGROUND

Increasing numbers of unstable pelvic ring fractures, due to the ongoing demographic change and improvements in the rescue of high-energy traumatic events, are challenging trauma and orthopedic surgeons. While initial installation of an external fixation device is often necessary, placement of iliac crest pins can be difficult due to the complex osteology of the ilium.

HYPOTHESIS

We aim to analyze (1) the length, localization and angulation of the iliac pillar and (2) to define the dimensions of the surgical corridor for a better understanding of pin entry point and trajectory, thus preventing shortcomings in anterior external fixation of pelvic ring injuries.

METHODS

Twenty hemipelvises from 10 fresh-frozen cadaveric torsos (3 female, 7 males; mean age 80.2 years) were harvested. The following measurements were taken with digital calipers: Location of the iliac pillar in relation to the anterior superior iliac spine and to the acetabulum roof, mean length and diameter of the iliac pillar, maximum diameter of the iliac pillar. In addition we measured the width of the different bone layers.

RESULTS

The mean length of the hourglass shaped iliac pillar was 107.04mm with a mean width of 17.0mm (min. 15.1; max. 19.2). The mean distance to the anterior superior iliac spine was 69.00mm (min. 64.8; max. 73.4). The mean maximum width of the iliac pillar was 12.16mm (min. 9.4; max. 13.8). Caudally the line describing the iliac pillar intercepts the cranial acetabular rim at 12 o'clock. The smallest mean diameter of the cancellous bone was 7.5mm±2.0.

CONCLUSION

The iliac pillar is part of the complex osteology of the human pelvis. A cohesive description of its location and dimensions has been lacking. Successful treatment of pelvic fracture depends on an optimal preoperative planning, accurate overall reduction, and stable fixation. We described the origin and angulation to provide a good bone stock for external fixation pin and the width of the different bone layers. This study therefore contributes by facilitating a thorough understanding of pelvic osteology and describing the location and dimensions of an optimal osseous pathway.

LEVEL OF EVIDENCE

Anatomical descriptive study.

Vaginal Extrusion of a Ventriculoperitoneal Shunt: A Case Report and Review of Literature

BACKGROUND

Ventriculoperitoneal shunting is the most common treatment for hydrocephalus (excessive cerebrospinal fluid accumulation in the brain), but has the potential for serious complications such as shunt migration. Potential migration sites include the lateral ventricle mediastinum, gastrointestinal tract, abdominal wall, bladder, vagina, and scrotum.

CASE

Here, we present a rare case of vaginal extrusion of a ventriculoperitoneal shunt.

SUMMARY AND CONCLUSION

Neurosurgeons and gynecologists should be aware of the potential occurrence of this rare complication.

The cubital tunnel: a radiologic and histotopographic study

Entrapment of the ulnar nerve at the elbow is the second most common compression neuropathy in the upper limb. The present study evaluates the anatomy of the cubital tunnel. Eighteen upper limbs were analysed in unembalmed cadavers using ultrasound examination in all cases, dissection in nine cases, and microscopic study in nine cases. In all cases, thickening of the fascia at the level of the tunnel was found at dissection. From the microscopic point of view, the ulnar nerve is a multifascicular trunk (mean area of 6.0 ± 1.5 mm(2) ). The roof of the cubital tunnel showed the presence of superimposed layers, corresponding to fascial, tendineous and muscular layers, giving rise to a tri-laminar structure (mean thickness 523 ± 235 μm). This multilayered tissue was hyperechoic (mean thickness 0.9 ± 0.3 mm) on ultrasound imaging. The roof of the cubital tunnel is elastic, formed by a myofascial trilaminar retinaculum. The pathological fusion of these three layers reduces gliding of the ulnar nerve during movements of the elbow joint. This may play a role in producing the symptoms typical of cubital tunnel syndrome. Independent from the surgical technique, decompression should span the ulnar nerve from the triceps brachii muscle to the flexor carpi ulnaris fascia.

Multiple variations of the hepatobiliary vasculature including a splenomesenteric trunk

Anatomical variations of the origins and branching patterns of the hepatobiliary system may be encountered during both surgical and laparoscopic procedures. We report the rare finding of a splenomesenteric trunk with an absent coeliac trunk in a 74-year-old female cadaver. Due to the absence of the coeliac trunk, the common hepatic artery was found to originate from the splenic artery. Embryological considerations and possible clinical consequences are discussed.

Princeps pollicis artery arising from the superficial palmar arch

We present a 48-year-old male cadaver in which the right superficial palmar arterial arch had no contribution from the radial artery and terminated by giving rise to a common trunk for the princeps pollicis and radialis indicis arteries. The dorsal radial artery of the thumb was absent and no arterial supply was provided by the radial artery. Accordingly, the entire arterial supply to the right thumb was provided by the superficial palmar arterial arch, which was composed solely of the ulnar artery, which received no collateral supply from the radial artery system. Considering that the arterial supply of the thumb in the present case was solely provided by the superficial palmar arch, a potential hazard could exist in the event of traumatic injury to the ulnar artery.

Death in shunted hydrocephalic children in the 1990s

Using a combined search of the Children's Hospital (Birmingham, Ala., USA) medical records and the Jefferson County Health Department death records, we reviewed all shunt-related deaths that occurred between January 1990 and July 1996. Of these, we excluded patients who died of nonhydrocephalus-related reasons, such as bronchopulmonary dysplasia, as well as patients who had other serious neurological illnesses such as brain tumor and hydranencephaly. Twenty-eight patients died of shunt-related causes in the 6.5-year period. A survival analysis showed that 96% survived 32 months after first shunting. Of 28 patients, 23 were beyond help prior to medical evaluation. However, at least 10 of these patients had symptoms suggestive of shunt failure at least 24 h and as long as 2 weeks prior to their demise. We conclude that hydrocephalic children still die of shunt failure despite the modern technology of the 1990s. Some of these causes may be avoidable through early detection of symptoms. Guidelines to patients, families, and primary caregivers should be emphasized.