A 3D reconstruction of pancreas development in the human embryos during embryonic period (Carnegie stages 15-23).

AIMS: The goal in this paper was to rebuild a three dimensional (3D) reconstruction of the dorsal and ventral pancreatic buds, in the human embryos, at Carnegie stages 15-23. METHOD: The early development of the pancreas is studied by tissue observation and reconstruction by a computer-assisted method, using a light micrograph images from consecutive serial sagittal sections (diameter 7 microm) of ten human embryos ranging from Carnegie stages 15-23, CRL 7-27 mm, fixed, dehydrated and embedded in paraffin, were stained alternately with haematoxylin-eosin or Heindenhain'Azan. The images were digitalized by Canon Camera 350 EOS D. The serial views were aligned automatically by software, manual alignment was performed, the data were analysed following segmentation and threshold. RESULTS: The two buds were clearly identified at stage 15. In stage 16, both pancreatic buds were in final position, and begin to merge in stage 17. From stage 18 to the stage 23, surrounding connective tissue differentiated. In the stage 23, the morphology of the pancreas was definitive. The superior portion of the anterior face of the pancreas's head was arising from the dorsal bud. The rest of the head including the uncinate process emanated from the ventral bud. CONCLUSION: The 3D computer-assisted reconstruction of the human pancreas visualized the relationships between the two pancreatic buds. This explains the disposition and the modality of the components fusion. This embryologic development permits a better understanding of congenital abnormalities.

Contribution to the 3D computer assisted reconstruction of pancreatic buds in the rat embryos.

The aim of this work was to reconstruct, in the rat embryos, stage 12-23, the three dimensional (3D) distribution of the dorsal and ventral pancreatic buds by of a computer assisted method. Ninety-six rat embryos, CRL 3-16 mm, fixed, dehydrated, and paraffin embedded, were submitted to serial histological sections and stained by hematoxylin-eosin and Heidenhain's azan techniques. The images were digitalized by Canon Camera 350 EOS D. The serial views were aligned anatomically by software and the data were analyzed following segmentation and thresholding. The dorsal pancreas developed from the dorsal wall of the duodenum in stage 12, while the ventral pancreas arose from the ventral wall of the hepatic diverticulum in stage 13 and 14. The rotation of ventral pancreas started in stage 15 and was completed in stage 16. The fusion of both buds was evident in stage 17. In stage 23 the limit between dorsal and ventral bud was still marked by the pathway of superior mesenteric vein.

Anatomical basis of transgluteal pudendal nerve block.

BACKGROUND: The pudendal nerve may become entrapped either within the pudendal canal or near the sacrotuberous ligament resulting in a partial conduction block. The goal of the present anatomical study was to assess a new transgluteal injection technique in terms of the precise injection site and the resulting distribution of the injected agent. MATERIALS AND METHODS: This study was carried out using eight fresh human cadavers. An epidural needle with a removable wing was inserted and the catheter position visualized using MRI. Through the catheter 10 ml of gadolinium contrast medium was injected into three of the cadavers. A further four cadavers were injected with latex and blue pigment and the pelvi-perineal area of each then separated from the trunk for freezing before being cut into 4-8 mm thick sections with an electric bandsaw. One final cadaver was injected with a mix of gadolinium (5 ml) and latex (5 ml) and both the MRI and anatomical procedures outlined above were performed. RESULTS: Using MRI, we clearly imaged both the site of injection, near the trunk of the pudendal nerve, and the gadolinium contrast medium in different pelvic and perineal areas and around the fascia of the obturator internus and levator ani muscle. Concerning the anatomical study, latex was observed mainly around the sacrotuberous ligament, along the obturator internus muscle and in the perineal area in contact with the dividing branches of the pudendal nerve. The mixed injection of latex and gadolinium in the pudendal canal was found with the same localization between MRI and anatomical studies. CONCLUSION: This easily performed technique should provide a new approach for treating perineal neuralgia via pudendal nerve block in the consultation room without the need for computed tomography.

What is the place of electroneuromyographic studies in the diagnosis and management of pudendal neuralgia related to entrapment syndrome?

Entrapment of the pudendal nerve may be at the origin of chronic perineal pain. This syndrome must be diagnosed because this can result in the indication of surgical decompression of the entrapped nerve for pain relief. Electroneuromyographic (ENMG) investigation is often performed in this context, based on needle electromyography and the study of sacral reflex and pudendal nerve motor latencies. The limits of ENMG investigation, owing to various pathophysiological and technical considerations, should be known. The employed techniques do not assess directly the pathophysiological mechanisms of pain but rather correlate to structural alterations of the pudendal nerve (demyelination or axonal loss). In addition, only direct or reflex motor innervation is investigated, whereas sensory nerve conduction studies should be more sensitive to detect nerve compression. Finally, ENMG cannot differentiate entrapment from other causes of pudendal nerve lesion (stretch induced by surgical procedures, obstetrical damage, chronic constipation...). Thus, perineal ENMG has a limited sensitivity and specificity in the diagnosis of pudendal nerve entrapment syndrome and does not give direct information about pain mechanisms. Pudendal neuralgia related to nerve entrapment is mainly suspected on specific clinical features and perineal ENMG examination provides additional, but no definitive clues, for the diagnosis or the localization of the site of compression. In fact, the main value of ENMG is to assess objectively pudendal motor innervation when a surgical decompression is considered. Perineal ENMG might predict the outcome of surgery but is of no value for intraoperative monitoring.

Sagittal alignment of spine and pelvis regulated by pelvic incidence: standard values and prediction of lordosis.

Pelvis and spinal curves were studied with an angular parameter typical of pelvis morphology: pelvic incidence. A significant chain of correlations between positional pelvic and spinal parameters and incidence is known. This study investigated standards of incidence and a predictive equation of lordosis from selective pelvic and spinal individual parameters. One hundred and forty nine (78 men and 71 women) healthy adults, aged 19-50 years, with no spinal disorders, were included and had a full-spine lateral X-ray in a standardised upright position. Computerised technology was used for the measurement of angular parameters. Mean-deviation section of each parameter and Pearson correlation test were calculated. A multivariate selection algorithm was running with the lordosis (predicted variable) and the other spinal and pelvic parameters (predictor variables), to determine the best sets of predictors to include in the model. A low incidence (<44 degrees ) decreased sacral-slope and the lordosis is flattened. A high incidence (>62 degrees ) increased sacral-slope and the lordosis is more pronounced. Lordosis predictive equation is based on incidence, kyphosis, sacral-slope and +/-T9 tilt. The confidence limits and the residuals (the difference between measured and predicted lordosis) assessed the predicted lordosis accuracy of the model: respectively, +/-1.65 and 2.41 degrees with the 4-item model; +/-1.73 and 3.62 degrees with the 3-item model. The ability of the functional spine-pelvis unit to search for a sagittal balance depended both on the incidence and on the variation section of the other positional parameters. Incidence gave an adaptation potential at two levels of positional compensation: overlying state (kyphosis, T9 tilt), underlying state (sacral slope, pelvic tilt). The biomechanical and clinical conditions of the standing posture (as in scoliosis, low back pain, spondylisthesis, spine surgery, obesity and postural impairments) can be studied by comparing the measured lordosis with the predicted lordosis.

Peribulbar versus retrobulbar anesthesia for ophthalmic surgery: an anatomical comparison of extraconal and intraconal injections.

BACKGROUND: Peribulbar and retrobulbar anesthesia have long been opposed on the basis of the existence of an intermuscular membrane, which is supposed to separate the intraconal from the extraconal spaces in a water-tight fashion. A local anesthetic injected outside the cone should spread through this septum to reach the nerves to be blocked. The existence of this septum is questioned. The aim of this study was to compare the spread of a colored latex dye injected intraconally or extraconally to simulate both retrobulbar and peribulbar anesthesia. METHODS: The authors used 10 heads from human cadavers. For each head, one eye was injected intraconally, and the other eye was injected extraconally. The heads were then frozen and sectioned into thin slices following various planes. They were then photographed and observed. RESULTS: There was no evidence of the existence of an intermuscular septum separating the intraconal and extraconal spaces. Those two spaces appeared to be part of a common spreading space, the corpus adiposum of the orbit. CONCLUSIONS: These results are in accord with the fact that clinical studies were not able to clearly demonstrate that retrobulbar anesthesia is more efficient than peribulbar anesthesia. On the basis of a similar clinical efficacy of the two techniques as a result of similar spreading of the local anesthetic injected, and a potentially higher risk of introducing the needle into the muscular cone, the authors recommend replacing retrobulbar anesthesia with peribulbar anesthesia.

Medial canthus episcleral (sub-Tenon) anesthesia imaging.

Medial canthus single injection periocular anesthesia is an alternative technique to classical regional anesthesia techniques for cataract surgery. The occurrence of a chemosis at the end of this injection has made us question ourselves about the real site of injection. The purpose of this anatomic study was to identify this site with precision, and to describe the spreading of the injected solution. Various volumes of colored liquid latex were injected when using this technique on 10 human orbits. They were deeply frozen and sectioned in thin slices. The site of injection is clearly the episceral (sub-Tenon) space. This is a gliding space through which pass the ciliary nerves supplying the globe sensitivity. This could explain the high quality of the analgesia of the globe. With the larger volumes injected, spreading of the latex was detected in the orbicularis palpebra. This probably explains the good akinesia of the lids obtained without any facial block. Spreading of the latex to the rectus muscles sheaths should explain the good akinesia of the globe, but was only partially proved in this study. We conclude that the medial canthus single injection periocular anesthesia is an episcleral (sub-Tenon) injection which may explain good anesthesia.

Medial canthus single-injection episcleral (sub-tenon anesthesia): computed tomography imaging.

UNLABELLED: Single-injection medial canthus periocular anesthesia is a promising regional anesthesia technique for ophthalmic surgery. The purpose of this computed tomography (CT) study was to confirm that this technique is an episcleral injection and to explain why it provides a good akinesia of the globe. Four fresh nonpreserved cadavers (eight eyes) were injected with fractioned various volumes of a contrast media using a previously described technique. For each injection and each eye, CT scans were performed in three planes of the space, and the site and spread of the injection was observed. We confirm that single-injection medial canthus periocular anesthesia is, in fact, an episcleral anesthesia, which explains the good sensory block of the globe. When larger volumes are injected, the contrast media spreads to the lids and extraocular muscle sheaths. We believe that this may explain why this technique provides good sensory and motor block of the globe and eyelids. This technique is a promising alternative to both retro- and peribulbar anesthesia. IMPLICATIONS: We describe medial canthus single-injection periocular anesthesia by a computed tomography injection study in eight human cadaver eyes. It was confirmed to be an episcleral injection. Akinesia of the eyeball is provided by spreading of the local anesthetic solution from the episcleral space to the rectus muscle sheaths.

Anatomic basis of chronic perineal pain: role of the pudendal nerve.

Our anatomic findings have led us to define conflictual relations that may be encountered in their course by the pudendal n. and its branches. Starting from the clinical study of a group of patients suffering from chronic perineal pain in the seated position, we have defined, beginning with the cadaver, three possible conflictual settings: in the constriction between the sacrotuberal and sacrospinal ligaments; in the pudendal canal of Alcock; and during the straddling of the falciform process of the sacro-tuberal ligament by the pudendal n. and its branches. Consequently, considering so-called idiopathic perineal pain as an entrapment syndrome, the clinical and neurophysiologic arguments and infiltration tests have led us to define a surgical strategy which has currently given 70% of good results in 170 operated patients. Earlier diagnosis should improve on this.

[Electrophysiologic studies in the descending perineum in women]. / Explorations électrophysiologiques dans les périnées descendants chez la femme.

Seventy five female patients (mean age: 55 +/- 13 years) were included into the study. Electromyography of the perineum with study of the intramuscular activity of the external anal sphincter was done and measures of the sacral reflex latency were obtained by stimulation of the cavernous nerve of the clitoris, recording in the external anal sphincter muscle. Neurogenic syndromes of pudendal nerve either isolated or associated with muscular disorders have been shown to be correlated with descending perineum. In our study, we investigated whether a history of obstetrical or surgical interventions is related to the occurrence of this syndrome. We did not find any significant relationship.

Medial canthus (caruncle) single injection periocular anesthesia.

We studied 151 consecutive patients scheduled for elective short-duration ophthalmic procedures to assess the efficacy of an alternative approach to periocular anesthesia. Single injection at the medial canthus was performed with a 25-gauge needle. The studied variables were: injected volume, onset time of the block, akinesia (scored on a 12-point scale), adequate surgical anesthesia (scored on a 5-point scale), and need for reinjection. The injected volume of local anesthetic solution was 8.6 +/- 1.7 mL. The onset time of anesthesia was 6.9 +/- 3.0 min, with an akinesia score of 11.6 +/- 1.1 (maximum 12). Additional reinjections were necessary in 14 cases (9.2%). There was a learning curve for the technique, with 8 of the additional injections being performed in the first 30 patients (26.6%), and 6 in the last 121 (4.9%). The surgical score recorded after surgery was 4.8 +/- 0.6 (maximum 5). There were no complications, including injury to the globe, optic nerve, or retina or orbital hematoma. Medial canthus single injection periocular anesthesia appears to be a promising alternative to the usual double injection peribulbar block.

[Female urinary stress incontinence and insufficient closing pressures. Results of perineal sphincter electromyography]. / Incontinence urinaire d'effort féminine et insuffisance des pressions de clôture. Que peut-on attendre de l'électromyographie des sphincters périneaux?

Prior to a clinical evaluation of the efficacy of sphincter and perineal rehabilitation in female urinary stress incontinence due to striated sphincter incompetence, and in order to define the cause, 32 patients with stress incontinence with very low urethral closing pressure on urodynamic studies, underwent a perineal electromyographic investigation Three types of sphincteric lesion were detected: an isolated lesion of the striated muscle fibres, an isolated neurogenic lesion of the internal pudendal nerve and a neurogenic lesion of the internal pudendal nerve in a context of sensorimotor polyneuropathy.