Manuela Perez

Discriminant study of the development of the mandibular units in a neural reference system

The mandible is a complex osteological structure composed of distinct units integrated into a single bone around the director axis of the mandibular nerve. In this study of the mandibular development, we use a method that synthesizes the contributions of each sub-unit, using the mandibular canal as reference system. This novel approach results in new informations and confirms the leading role of the mandibular nerve and of its curve in mandibular development. It would seem to be possible to explain a major part of mandibular development by the role of the nerve as guide.

The olfactory fascia: an evo–devo concept of the fibrocartilaginous nose

PurposeEvo–devo is the science that studies the link between evolution of species and embryological development. This concept helps to understand the complex anatomy of the human nose. The evo–devo theory suggests the persistence in the adult of an anatomical entity, the olfactory fascia, that unites the cartilages of the nose to the olfactory mucosa.MethodsWe dissected two fresh specimens. After resecting the superficial tissues of the nose, dissection was focused on the disarticulation of the fibrocartilaginous noses from the facial and skull base skeleton.ResultsDissection shows two fibrocartilaginous sacs that were invaginated side-by-side in the midface and attached to the anterior skull base. These membranous sacs were separated in the midline by the perpendicular plate of the ethmoid. Their walls contained the alar cartilages and the lateral expansions of the septolateral cartilage, which we had to separate from the septal cartilage. The olfactory mucosa was located inside their cranial ends.ConclusionThe olfactory fascia is a continuous membrane uniting the nasal cartilages to the olfactory mucosa. Its origin can be found in the invagination and differentiation processes of the olfactory placodes. The fibrous portions of the olfactory fascia may be described as ligaments that unit the different components of the olfactory fascia one to the other and the fibrocartilaginous nose to the facial and skull base skeleton. The basicranial ligaments, fixing the fibrocartilaginous nose to the skull base, represent key elements in the concept of septorhinoplasty by disarticulation.

A guide for effective anatomical vascularization studies: useful ex vivo methods for both CT and MRI imaging before dissection

The objective of this study was to develop a simple and useful injection protocol for imaging cadaveric vascularization and dissection. Mixtures of contrast agent and cast product should provide adequate contrast for two types of ex vivo imaging (MRI and CT) and should harden to allow gross dissection of the injected structures. We tested the most popular contrast agents and cast products, and selected the optimal mixture composition based on their availability and ease of use. All mixtures were first tested in vitro to adjust dilution parameters of each contrast agent and to fine‐tune MR imaging acquisition sequences. Mixtures were then injected in 24 pig livers and one human pancreas for MR and computed tomography (CT) imaging before anatomical dissection. Colorized latex, gadobutrol and barite mixture met the above objective. Mixtures composed of copper sulfate (CuSO4) gadoxetic acid (for MRI) and iodine (for CT) gave an inhomogeneous signal or extravasation of the contrast agent. Agar did not harden sufficiently for gross dissection but appears useful for CT and magnetic resonance imaging (MRI) studies without dissection. Silicone was very hard to inject but achieved the goals of the study. Resin is particularly difficult to use but could replace latex as an alternative for corrosion instead of dissection. This injection protocol allows CT and MRI images to be obtained of cadaveric vascularization and anatomical casts in the same anatomic specimen. Post‐imaging processing software allow easy 3D reconstruction of complex anatomical structures using this technique. Applications are numerous, e.g. surgical training, teaching methods, postmortem anatomic studies, pathologic studies, and forensic diagnoses.

Does Anatomy Explain the Origin of a Leak After Sleeve Gastrectomy? Comments & Answers

Dear Editors, We would like to thank Dr. El-shoek et al. for their comments and interest about our recently published paper on gastric leak after sleeve gastrectomy for morbid obesity (OBSU-D-13-00566—Does anatomy explain the origin of a leak after sleeve gastrectomy? Perez M, Brunaud L, Kedaifa S, Guillotin C, Gerardin A, Quilliot D, Grosdidier G, Reibel N. Obes Surg. 2014 Oct;24(10):1717–23). Please find below our answer for each of your questions or comments.

Unraveling Pancreatic Segmentation

BackgroundLimited pancreatic resections are increasingly performed, but the rate of postoperative fistula is higher than after classical resections. Pancreatic segmentation, anatomically and radiologically identifiable, may theoretically help the surgeon removing selected anatomical portions with their own segmental pancreatic duct and thus might decrease the postoperative fistula rate. We aimed at systematically and comprehensively reviewing the previously proposed pancreatic segmentations and discuss their relevance and limitations.MethodsPubMed database was searched for articles investigating pancreatic segmentation, including human or animal anatomy, and cadaveric or surgical studies.ResultsOverall, 47/99 articles were selected and grouped into 4 main hypotheses of pancreatic segmentation methodology: anatomic, vascular, embryologic and lymphatic. The head, body and tail segments are gross description without distinct borders. The arterial territories defined vascular segments and isolate an isthmic paucivascular area. The embryological theory relied on the fusion plans of the embryological buds. The lymphatic drainage pathways defined the lymphatic segmentation. These theories had differences, but converged toward separating the head and body/tail parts, and the anterior from posterior and inferior parts of the pancreatic head. The rate of postoperative fistula was not decreased when surgical resection was performed following any of these segmentation theories; hence, none of them appeared relevant enough to guide pancreatic transections.ConclusionCurrent pancreatic segmentation theories do not enable defining anatomical–surgical pancreatic segments. Other approaches should be explored, in particular focusing on pancreatic ducts, through pancreatic ducts reconstructions and embryologic 3D modelization.

A radio-anatomical correlation study of the cisterna chyli

Surgical laparoscopic procedures in the retroperitoneal and supramesocolic spaces are increasingly frequent. There is a high risk of iatrogenic intraoperative injury of the retroperitoneal lymphatic structures during these procedures. A precise understanding of the anatomy of the thoracic duct (TD) and the cisterna chyli (CC) is essential for safe surgical procedures in this area. However, routine imaging procedures rarely and often incorrectly visualize the CC. The objective of this study was to evaluate the feasibility of a retrograde injection of the TD to fill the CC with a contrast agent in 16 human cadavers. Both magnetic resonance lymphography (MRI) and computed tomography (CT) studies could be performed on the same anatomical specimen, using a contrast medium which hardened, allowing gross dissection. MRI and CT detectability were evaluated, and imaging results were compared with the anatomical dissection. The CC of 12/16 cadavers were successfully injected, and four were unsuccessful due to technical difficulties, showing the effectiveness of the method. This technique can improve understanding of the anatomy of the TD and CC and provides an original option to study the complex anatomy of these structures by correlating precise cadaveric dissections with cross‐sectional imaging.