Aldo Junqueira Rodrigues

Endoscopic anatomy of the pterygopalatine fossa and the transpterygoid approach: development of a surgical instruction model.

Introduction: The pterygopalatine fossa (PPF) is a narrow space located between the posterior wall of the antrum and the pterygoid plates. Surgical access to the PPF is difficult because of its protected position and its complex neurovascular anatomy. Endonasal approaches using rod lens endoscopes, however, provide better visualization of this area and are associated with less morbidity than external approaches. Our aim was to develop a simple anatomical model using cadaveric specimens injected with intravascular colored silicone to demonstrate the endoscopic anatomy of the PPF. This model could be used for surgical instruction of the transpterygoid approach.

The value of teaching sectional anatomy to improve CT scan interpretation.

A specific course on sectional anatomy was developed to help medical students improve their knowledge of cross‐sectional imaging. The educational methodology consists of identifying anatomical structures displayed in plastinated sections from human cadavers and corresponding anatomical structures in computed tomography (CT) sections from healthy patients. The course has a self‐study format. To assess and verify the impact of learning sectional anatomy on radiological knowledge, students were asked to identify ten anatomical structures in CT images. This test was applied to two groups of students: Group I had been taught sectional anatomy with CT images 2 years before the test; Group II had not received instruction in sectional anatomy prior to the test. Analysis of the results revealed a significant difference in test scores (median percentages of correctly identified structures) between Group I and Group II, with scores of 100% and 63.4%, respectively. These results provide evidence that the inclusion of sectional anatomy training in medical school curricula has a great impact on subsequent CT interpretation. Clin. Anat. 14:36–41, 2001.

Surgical Anatomy of Microneurosurgical Sulcal Key Points

OBJECTIVE: The brain sulci constitute the main microanatomic delimiting landmarks and surgical corridors of modern microneurosurgery. Because of the frequent difficulty in intraoperatively localizing and visually identifying the brain sulci with assurance, the main purpose of this study was to establish cortical/sulcal key points of primary microneurosurgical importance to provide a sulcal anatomic framework for the placement of craniotomies and to facilitate the main sulci intraoperative identification. METHODS: The study was performed through the evaluation of 32 formalin-fixed cerebral hemispheres of 16 adult cadavers, which had been removed from the skulls after the introduction of plastic catheters through properly positioned burr holes necessary for the evaluation of cranial–cerebral relationships. Three-dimensional anatomic and surgical images are displayed to illustrate the use of sulcal key points. RESULTS: The points studied were the anterior sylvian point, the inferior rolandic point, the intersection of the inferior frontal sulcus with the precentral sulcus, the intersection of the superior frontal sulcus with the precentral sulcus, the superior rolandic point, the intersection of the intraparietal sulcus with the postcentral sulcus, the superior point of the parieto-occipital sulcus, the euryon (the craniometric point that corresponds to the center of the parietal tuberosity), the posterior point of the superior temporal sulcus, and the opisthocranion, which corresponds to the most prominent point of the occipital bossa. These points presented regular neural and cranial–cerebral relationships and can be considered consistent microsurgical cortical key points. CONCLUSION: These sulcal and gyral key points can be particularly useful for initial intraoperative sulci identification and dissection. Together, they compose a framework that can help in the understanding of hemispheric lesion localization, in the placement of supratentorial craniotomies, as landmarks for the transsulcal approaches to periventricular and intraventricular lesions, and in orienting the anatomic removal of gyral sectors that contain infiltrative tumors.

Aging of the elastic and collagen fibers in the human cervical interspinous ligaments

BACKGROUND CONTEXT The ligaments consist of collagen bands intermingled with elastic fibers that support hundreds of pounds of stress per square inch. In the spine the basic functional unit comprises vertebrae, intervertebral disc and ligament tissues. The interspinous ligaments with the function of limiting the spine flexion are exposed to a traumatic and degenerative process that promotes pain or instability. It has been shown that aging induces structural changes to capsular, fascial and ligamentous structures, mainly to the elastic and collagen fibers. However, the relative changes with age in elastic and collagen fibers have not been quantified. PURPOSE Examine the changes in the arrangement and amount of the elastic and collagen fibers of the human cervical interspinous ligament and attempt to correlate them with age. STUDY DESIGN/SETTING Histomorphometric analysis of ligament samples harvested during surgery. PATIENT SAMPLE We studied the dorsal portion of this ligament from 17 patients aged 16 to 69 years. OUTCOME MEASURES Fraction of collagen and elastic fibers with linear regression analysis correlating fraction versus age. METHODS The elastic and collagen fibers were identified by selective staining methods, and a blinded investigator using an image analysis system performed the histomorphometry. RESULTS There is an age-related progressive increase in collagen and mature and elaunin elastic fibers responsible to elasticity. However, these elastic fibers showed structural degenerative changes with aging. Furthermore, there is an age-related decrease of oxytalan elastic fibers responsible to resistance. CONCLUSIONS The aged interspinous ligament showed loss of elasticity that could alter the flexion limiting of the vertebral column.

Prosthetic repair of incisional hernia in kidney transplant patients. A technique with onlay polypropylene mesh

The employment of synthetic mesh for incisional hernia repair in kidney-transplanted patients is rarely reported in the present literature. Many authors believe that mesh employment in such conditions is not safe due to fear of mesh related complications. From 1965 through 1999, a total of 1685 kidney transplants were performed at our Kidney Transplant Unit and 19 patients developed eventrations in the kidney transplant incision, an incidence of 1.1%. From September 1996 eight of these patients had prosthetic repair of the abdominal wall with onlay polypropylene mesh. All patients were under immunosuppressive therapy with prednisone, ciclosporine and azathioprine. Mean age was 48.8 years, mean body mass index was 22.5 and mean number of previous abdominal operations was 2.5. A large polypropylene mesh (Marlex® mesh) was fixed over the aponeurosis after primary closure of the aponeurotic borders, as an onlay graft. There was neither morbidity nor mortality associated to the surgical procedure. No recurrences or long-term complications associated with mesh employment were verified after a follow-up ranging from one year to three years. We concluded that prosthetic repair of incisional hernia in transplanted patients can be performed routinely.

The effects of prenatal intraamniotic surfactant or dexamethasone administration on lung development are comparable to changes induced by tracheal ligation in an animal model of congenital diaphragmatic hernia

BACKGROUND/PURPOSE Lung surfactant deficiency contributes to the pathophysiology of congenital diaphragmatic hernia (CDH) and the high neonatal mortality rate. Acceleration of lung surfactant system maturation by prenatal administration of hormones has been described in animal models of CDH. However, in utero tracheal ligation (TL) is the best method to accelerate lung growth and reverse the pulmonary hypoplasia associated with CDH. Although this method offers promise, its application in humans is limited. The aim of this study was to investigate a new noninvasive therapeutic strategy, that is, the prenatal intraamniotic administration of exogenous porcine surfactant or dexamethasone, and compare it with the effects of TL in an animal model of CDH. METHODS Twenty-four pregnant New Zealand rabbits underwent surgery on gestational day 24 or 25 to create CDH in 26 fetuses. Five groups of animals were studied: (1) Control, nonoperated fetuses (n=14), (2) CDH (n=6), (3) CDH plus TL (n 6), (4) CDH plus intraamniotic administration of Curosurf (40 mg; n=6), and (5) CDH plus intraamniotic infusion of dexamethasone (0.4 mg; n=8). On gestational day 30, the fetuses were delivered by cesarean section. Functional studies (lung hysteresis curves and lung distensibility), weight and volume of lungs, histopathologic and histomorphometric analysis of lungs were performed. RESULTS The authors demonstrated that the hysteresis curve of CDH animals was shifted downward in comparison with controls. The analyses of curves standardized for lung weight indicated that intraamniotic administration of surfactant or dexamethasone improved lung compliance in comparison with controls and CDH fetuses, but TL had no effect on this parameter. Lung distensibility (maximum lung volume at 32 cm of water pressure per gram of lung) was reduced by CDH, but this parameter was increased by intraamniotic administration of drugs and not by TL (P< .05). CDH decreased the weight and volume of lungs (P< .05), and these changes were reversed only by TL, which prevented the herniation of the liver from the abdomen to the thorax. Histologically, CDH lungs treated with TL or intraamniotic administration of drugs demonstrated structural patterns similar to those of controls. Histomorphometric studies proved that CDH promoted significant thickening of septa walls (P< .05), and all the therapeutic methods could reverse this alteration to control values. The alveolar number per area in control lungs, CDH, and CDH plus TL lungs were similar, but in CDH plus surfactant and CDH plus dexamethasone lungs, the decreased number per area (P< .05) demonstrated that the alveolar airspace was increased. CONCLUSION From these data the authors conclude that intraamniotic surfactant or dexamethasone administration is capable of preventing pulmonary hypoplasia in fetuses with CDH, and thus, this method may be a substitute for TL.

Referências anatômicas na cirurgia do implante auditivo de tronco cerebral

Auditory brainstem implant (ABI) is an option for deaf patients who do not have the whole auditory pathways preserved. The surgery, because of its anatomical and functional complexity, requires specific training of the surgeon in an anatomy lab. AIM: To study the surgical anatomy of the auditory brainstem implant surgery. STUDY DESIGN: Anatomic study. MATERIAL AND METHOD: In the present study, we dissected a fresh cadaver prepared with a dye solution injected into the arteries and intracranial veins. The location of the insertion of the ABI electrode was studied through translabyrinthine access. RESULTS: The surgical technique used for implanting the brainstem electrode is similar to that used in the removal of vestibular schwannoma. The cochlear nucleus complex, comprising ventral and dorsal cochlear nuclei, is the optimal electrode site. The ventral cochlear nucleus is the principal nucleus for transmission of neural impulses from the 8th pair and form the main ascending route of the cochlear nerve. Neither the ventral nor the dorsal nuclei are visible during surgery and their location depends on the identification of adjacent anatomical structures. CONCLUSION: The region for the implantation of the electrode in the auditory brainstem implant presents anatomical landmarks that allow its easy identification during surgery.

Differences in tumour growth, tumour cell proliferation and immune function after laparoscopy and laparotomy in an animal model

BACKGROUND Clinical and experimental studies have shown that laparoscopy preserves the immune response and can give better clinical results than laparotomy. However, the use of laparoscopy for the treatment of cancer patients is still controversial due to the risk of port-site and haematogenous metastases and increased tumour growth. The purpose of this experimental study was to assess tumour growth and the mechanism of differential tumour behaviour after laparoscopy and laparotomy. METHODS Seventy-five young, male Wistar rats were randomly assigned to one of two experiments. Experiment 1: 45 animals were inoculated subcutaneously with Walker carcinosarcoma 256 cells and were subdivided into three groups of 15 rats. Control group la was submitted to anaesthesia only, group 1b received carbon dioxide (CO(2)) pneumoperitoneum,while group 1c received a laparotomy. Animals were sacrificed on postoperative day (POD) 7; tumours were excised and weighed to evaluate tumour growth. Nucleolar organiser regions identified by silver staining (AgNORs) were analysed to evaluate cell proliferation. Experiment 2: 30 rats were submitted to the same procedures as before, with ten animals in each group (2a, 2b, 2c), and a delayed-type hypersensitivity response (DTH) was used to evaluate the immune function. RESULTS The average tumour mass was 1.76 g in group 1a, 2.81 g in group 1b and 4.21 g in group 1c (p < 0.05). The AgNOR expression results were similar in the three groups. The immune function was better preserved in the control group (2a: average inflammatory area on POD1 = 106 mm(2) and on POD2 = 128.18 mm(2)), than in the pneumoperitoneum group (2b: average inflammatory area on POD1 = 79.75 mm(2) and on POD2 = 126.93 mm(2)); the worst results were in the laparotomy group (2c: average inflammatory area on POD1 = 33.33 mm(2) and on POD2 = 61.32 mm(2)).There were significant differences between groups 2a and 2c and between 2b and 2c. CONCLUSION Laparotomy stimulates a greater tumour growth than CO(2) pneumoperitoneum, but there is no difference in tumour cell proliferation. The cellular immune function is better preserved in animals submitted to CO pneumoperitoneum than in the laparotomized animals. These results suggest a relationship between a weaker immune response and a greater tumour growth.

A comparison of the effects of pneumoperitoneum and laparotomy on Natural Killer cell mediated cytotoxicity and Walker tumor growth in Wistar rats

BackgroundSurgical stress promotes impaired immunological function, which contributes to tumor growth. Natural killer activity (NKA) has a protective role in immunity to tumors. So, the aim of this experimental study was to assess tumor growth and (NKA) after pneumoperitoneum and laparotomy.MethodsSixty male Wistar rats were divided into three groups (anesthesia, CO2 pneumoperitoneum and laparotomy) plus ten controls. All experimental animals were inoculated subcutaneously with 8x105 Walker carcinosarcoma 256 cells. Animals were sacrificed on 1st(POD1) and 8th(POD8) postoperative day. Tumors were excised and weighed.ResultsOn POD1 all animals had diminished NKA when compared to controls; NKA after pneumoperitoneum was significantly greater than after laparotomy. On POD8 all animals, except after laparotomy, reached NKA at controls levels. Tumor weight was significantly greater after laparotomy when compared to pneumoperitoneum.ConclusionsPneumoperitoneum causes a less depressed NKA and less tumor growth when compared to laparotomy.

The Stoppa procedure in inguinal hernia repair: to drain or not to drain

OBJECTIVE The objective of this study is to evaluate the benefits of drainage in the Stoppa procedure for inguinal repair. PATIENTS AND METHODS The use of a suction drain was randomized at the end of the surgical intervention in 26 male patients undergoing inguinal hernia repair, divided into 2 groups: Group A, 12 patients undergoing drainage, and group B, 14 patients not undergoing drainage. On the second postoperative day, all patients underwent abdominal pelvic computed tomography scan examination to detect the presence of abdominal fluid collection. RESULTS In group A, no patient developed fluid collection in the preperitoneal space, and 1 patient presented with an abscess in the preperitoneal space on the 15th postoperative day. In group B, 12 patients presented with fluid collections in the preperitoneal space on computed tomography scan evaluation. However, only 3 patients presented minor complications. None of the patients developed a major complication. CONCLUSION The use of suction drainage with the Stoppa procedure does not provide any benefit.