Proximal Limit Research Articles

Is the Pressure Control Mode for Pediatric Anesthesia Machines Really Required?

Dear Editor, Choosing an appropriate anesthesia machine for mechanical ventilation of pediatric patients is of paramount importance because small changes in the fractions of the delivered tidal volume can cause a significant difference from the desired tidal volume. The anesthesia machines have classically been divided up into pressure or volume controlled modes, with two main characteristics; the limit (what determines the size of the breath), and the cycle (what actually ends the breath). The traditional anesthesia machines with volume controlled mode are not able to deliver precisely small tidal volumes to the pediatric patients. In the traditional anesthesia machines, fresh gas directly streams to the breathing circuit, so if 6 L/min of fresh gas is added to the previous setting (6 liters/60 seconds) 100 mL/s will be added to the delivered tidal volume, and if the inspiratory time is 2 seconds, 200 mL will be added to the tidal volume. These differences significantly increase the desired tidal volume. Therefore, the conventional anesthesia machines with the volume-controlled ventilation mode are not suitable to deliver a tidal volume less than 200 mL. During ventilation of neonates or children (in which tidal volume is less than 200 cc, respiratory rate is at least 16 - 20/minute and with a 1:2 I/E ratio, inspiratory time is less than 1 second), these differences are not acceptable. Thus, anesthesiologists usually use pressure-controlled ventilation rather than volume-controlled ventilation for pediatric anesthesia. A pressure-limited, time-cycled pulmonary ventilator includes a pressurized gas system that supplies respiratory gas to a patient at a selected inspiratory flow rate; an exhalation valve that opens an expiratory flow path in response to the elapsing of a selected inspiratory time period, and maintains a selected proximal pressure limit during the inspiratory time period. The tidal volume that results from a pressure-targeted machine is attributable to the set inspiratory pressure and patient’s lung-thorax compliance. Circuit compliance, fresh gas flow changes, and even small leaks around an un-cuffed endotracheal tube do not modify the delivered tidal volume (1). Pressure-controlled ventilation offers the advantage of limiting barotrauma in the condition of changing lung compliance, but a decrease in tidal volume will occur in the pressure-controlled ventilation mode, when the compliance of the lung is decreased or a pressure against the abdomen is created (e.g. in laparoscopic surgeries) (2). There are also some pediatric ventilators that deliver the breath by setting the inspiratory and expiratory duration and setting the flow of gas, but management of patients with these ventilators can lead to hypoventilation in the circumstance of increasing of the pulmonary resistance or reversal of muscle relaxants. To deliver a precise tidal volume, some new anesthesia machines have equipped with fresh gas decoupling valves. In these machines, the fresh gas (FGF) is not delivered to the inspiratory limb during inspiration. Practically, it means that FGF does not increase the tidal volume. The function of the fresh gas decoupling valve is to provide a precise delivery of the set tidal volume unaffected by varying fresh gas flow rates. During the inspiratory phase of ventilation, the valve closes, allowing only gas from the ventilator piston chamber to be delivered through the inspiratory branch to the patient. During the expiratory phase, the valve opens, allowing the ventilator piston chamber to fill with a mixture of the exhaled gas that has passed through the absorber and fresh gas (3). A second method for accurate delivery of desired tidal volume is compliance compensation, to replace volume lost to the breathing tubes. A potentially large percentage of the bellows volume is lost into the breathing circuit, secondary to compliance and compression. Leaks and sampled gas flow will further reduce desired tidal volume (4). To ensure that the set tidal volume will be delivered to the patients, new anesthesia machines involve a preuse leak and compliance test during which the end of the circuit must be occluded. The total compliance will be measured and the machine use this data to adjust piston or bellows movement, according to desired pressure airway setting (5). The anesthesiologist can use volume-controlled ventilation by a modern anesthesia machine that equipped with fresh gas decoupling valves and compliance and fresh gas compensation technology with confidence. Minimal tidal volume as low as 30 mL can be delivered precisely (5). The anesthesiologist should not persist in ordering a ventilator with multiple ventilation modes. Rather, choosing a ventilator with a unique mode that delivers a precise tidal volume would be suitable.

The Expanded Endoscopic Endonasal Approach to Anterior Communicating Artery Aneurysms: A Cadaveric Morphometric Study

The purpose of this study was to explore the endoscopic endonasal approach to the anterior communicating artery complex. Anatomic, morphometric analysis of human cadaver heads. Fifteen latex-injected adult cadaver heads. The anatomic boundaries of the operative field and the dimensions of exposure of the anterior communicating artery (ACoA) complex were measured and clip placement feasibility was assessed. Exposure of the ACoA and bilateral A1 and A2 segments was accomplished in all 15 cadaver heads. Average length of the exposed ACoA was 3 ± 1 mm, the left A1 was 5 ± 3 mm and right A1 was 5 ± 1 mm, while the A2 segment was 5 ± 2 mm bilaterally. The average distance from the alar floor to the ACoA was 95 mm, while proximal lateral limit measured between the alar floor margins was 36 mm. The distal lateral limit as defined by the distance between the lateral most exposed margins of the chiasm was 19 mm. Clip placement was accomplished for the ACoA and the A1 and A2 segments bilaterally in all specimens. The endoscopic, endonasal transtuberculum, transplanum approach is an anatomically feasible alternative to treating select aneurysms of the ACoA complex.

Use of superficial peroneal nerve graft for treating peripheral nerve injuries

ObjectiveTo evaluate the clinical results from treating chronic peripheral nerve injuries using the superficial peroneal nerve as a graft donor source. MethodsThis was a study on eleven patients with peripheral nerve injuries in the upper limbs that were treated with grafts from the sensitive branch of the superficial peroneal nerve. The mean time interval between the dates of the injury and surgery was 93 days. The ulnar nerve was injured in eight cases and the median nerve in six. There were three cases of injury to both nerves. In the surgery, a longitudinal incision was made on the anterolateral face of the ankle, thus viewing the superficial peroneal nerve, which was located anteriorly to the extensor digitorum longus muscle. Proximally, the deep fascia between the extensor digitorum longus and the peroneal longus muscles was dissected. Next, the motor branch of the short peroneal muscle (one of the branches of the superficial peroneal nerve) was identified. The proximal limit of the sensitive branch was found at this point. ResultsThe average space between the nerve stumps was 3.8cm. The average length of the grafts was 16.44cm. The number of segments used was two to four cables. In evaluating the recovery of sensitivity, 27.2% evolved to S2+, 54.5% to S3 and 18.1% to S3+. Regarding motor recovery, 72.7% presented grade 4 and 27.2% grade 3. There was no motor deficit in the donor area. A sensitive deficit in the lateral dorsal region of the ankle and the dorsal region of the foot was observed. None of the patients presented complaints in relation to walking. ConclusionsUse of the superficial peroneal nerve as a graft source for treating peripheral nerve injuries is safe and provides good clinical results similar to those from other nerve graft sources.

A New Pathologic Assessment of Gastroesophageal Reflux Disease: The Squamo-Oxyntic Gap.

Diagnosis of gastroesophageal reflux disease (GORD) is delayed by the lack of uniform histopathologic criteria for diagnosis. The only practical value of pathology is the assessment of columnar lined esophagus (CLO). As a result, GORD is treated with acid suppressive drug therapy until there is a failure to control symptoms and/or advanced adenocarcinoma develops. The reasons why there is a failure of pathologic diagnosis are two false dogmas that result in two widely believed fundamental errors. These are the belief that cardiac epithelium normally lines the proximal stomach (1) and that the gastroesophageal junction (GOJ) is defined by the proximal limit of rugal folds (2). When these false dogmas are eradicated by existing powerful evidence, the pathology of GERD falls into the following stages, all defined by histology: (a) The normal state where the esophageal squamous epithelium transitions at the GOJ to gastric oxyntic epithelium with no intervening cardiac epithelium; (b) cardiac metaplasia of the squamous epithelium due to exposure to gastric juice results in cephalad movement of the squamo-columnar junction (SCJ). This creates the squamo-oxyntic gap and the dilated distal esophagus, which is distal to the endoscopic GOJ. The length of the squamo-oxyntic gap in the dilated distal esophagus is concordant with the shortening of the abdominal segment of the lower esophageal sphincter (LOS); (c) in the early stages, the gap is <5 mm and the LOS retains its competence. Reflux is uncommon and patients are asymptomatic; (d) the squamo-oxyntic gap increases in length, concordant with the amount of shortening of the LOS, which becomes increasingly incompetent. At a gap length of 5-15 mm, reflux is sufficient to cause symptoms, but in most patients, symptoms are controllable and the patients are normal at endoscopy. The gap is entirely within the dilated distal esophagus, which is mistaken by present criteria for proximal stomach. (e) The last stage of GORD is when the squamo-oxyntic gap is >15 mm. In these patients, reflux is severe with increasingly uncontrollable symptoms and columnar lined esophagus, both irreversible states.Understanding this pathophysiology of GORD by these new histologic criteria will allow diagnosis at the earliest and eminently reversible stages of the disease. This can open the door to new methods of treatment that will have the potential to prevent progression to the irreversible phase of GORD, including columnar lined esophagus. If successful, this will effectively prevent progression to adenocarcinoma.

Emprego do enxerto do nervo fibular superficial para tratamento de lesões de nervos periféricos

ObjectiveTo evaluate the clinical results from treating chronic peripheral nerve injuries using the superficial peroneal nerve as a graft donor source. MethodsThis was a study on eleven patients with peripheral nerve injuries in the upper limbs that were treated with grafts from the sensitive branch of the superficial peroneal nerve. The mean time interval between the dates of the injury and surgery was 93 days. The ulnar nerve was injured in eight cases and the median nerve in six. There were three cases of injury to both nerves. In the surgery, a longitudinal incision was made on the anterolateral face of the ankle, thus viewing the superficial peroneal nerve, which was located anteriorly to the extensor digitorum longus muscle. Proximally, the deep fascia between the extensor digitorum longus and the peroneal longus muscles was dissected. Next, the motor branch of the short peroneal muscle (one of the branches of the superficial peroneal nerve) was identified. The proximal limit of the sensitive branch was found at this point. ResultsThe average space between the nerve stumps was 3.8cm. The average length of the grafts was 16.44cm. The number of segments used was two to four cables. In evaluating the recovery of sensitivity, 27.2% evolved to S2+, 54.5% to S3 and 18.1% to S3+. Regarding motor recovery, 72.7% presented grade 4 and 27.2% grade 3. There was no motor deficit in the donor area. A sensitive deficit in the lateral dorsal region of the ankle and the dorsal region of the foot was observed. None of the patients presented complaints in relation to walking. ConclusionsUse of the superficial peroneal nerve as a graft source for treating peripheral nerve injuries is safe and provides good clinical results similar to those from other nerve graft sources.

Rat Model of Parkes Weber Syndrome.

The Parkes Weber syndrome is a congenital vascular malformation, characterized by varicose veins, arterio-venous fistulas and overgrown limbs. No broadly accepted animal model of Parkes Weber syndrome has been described. We created side-to-side arterio-venous fistula between common femoral vessels with proximal non-absorbable ligature on common femoral vein limiting the enlargement of the vein diameter in Wistar rats. Contralateral limb was sham operated. Invasive blood pressure measurements in both iliac and inferior cava veins were performed in rats 30 days after fistula creation. Tight circumference and femoral bone length were measured. Histopathology and morphology of soleus muscle, extensor digitorum longus muscle, and the common femoral vessel were analyzed. 30 days following arterio-venous fistula creation, a statistically significant elevation of blood pressure in common iliac vein and limb overgrowth was observed. Limb enlargement was caused by muscle overgrowth, varicose veins formation and bone elongation. Arterio-venous fistula with proximal outflow limitation led to significant increase of femoral vein circumference and venous wall thickness. Our study indicates that the described rat model mimics major clinical features characteristic for the human Parkes Weber syndrome: presence of arterio-venous fistula, venous hypertension and dilatation, varicose veins formation, and the limb hypertrophy. We reveal that limb overgrowth is caused by bone elongation, muscle hypertrophy, and venous dilatation. The newly established model will permit detailed studies on the mechanisms underlying the disease and on the efficacy of novel therapeutic strategies for the Parkes Weber syndrome treatment.

Claw length recommendations for dairy cow foot trimming

The aim was to describe variation in length of the dorsal hoof wall in contact with the dermis for cows on a single farm, and hence, derive minimum appropriate claw...

Zero-energy peak and triplet correlations in nanoscale superconductor/ferromagnet/ferromagnet spin valves

Using a self-consistent Bogoliubov-de Gennes approach, we theoretically study the proximity-induced density of states (DOS) in clean SFF spin-valves with noncollinear exchange fields. Our results clearly demonstrate a direct correlation between the presence of a zero energy peak (ZEP) in the DOS spectrum and the persistence of spin-1 triplet pair correlations. By systematically varying the geometrical and material parameters governing the spin-valve, we point out to experimentally optimal system configurations where the ZEPs are most pronounced, and which can be effectively probed via scanning tunneling microscopy. We complement these findings in the ballistic regime by employing the Usadel formalism in the full proximity limit to investigate their diffusive SFF counterparts. We determine the optimal normalized ferromagnetic layer thicknesses which result in the largest ZEPs. Our results can serve as guidelines in designing samples for future experiments.

Abstract P3-11-11: Dedicated breast PET (dbPET) a unique functional new tool to accurate quantify response to neoadjuvant therapy in breast cancer

Abstract Background: Breast cancer is one of the most common cancers in women. Approximately 232,670 new cases of breast cancer (14% of all new cancer cases) and 40,000 breast cancer deaths (6,8% of all cancer deaths) are expected to occur among US women in 2014. Since 1990, breast cancer death rates have dropped by 34%. Continued progress in the control of breast cancer will require sustained and increased efforts to provide high-quality screening, diagnosis, and treatment Recently, the MAMmography with Molecular Imaging (MAMMI) dedicated breast PET (dbPET) has emerged as an additional imaging tool for breast cancer diagnosis, clarification of complex lesions and therapy follow-up. This study is aimed to determine whether correlations exist between physiological images with 18FDG of pre, post-2-cycles and post Neoadjuvant Chemotherapy, with a predictive value of response. Methods: Twenty-five patients, and three scan points: pre, 2 cycle and post Neoadjuvant Chemotherapy were included in this analysis A prone position high-resolution dedicated breast PET (MAMMI-dbPET) was performed 60 min after administration of 90-120 MBq of 18F-FDG. Maximum standardized uptake value (SUVmax) quantification, volume characterization, positioning in all three space-axes, distances to reference points (proximal breast limit, nipple areola complex) were registered. Results: When treatment was successful, a significant difference was found between pre and post neoadyuvant chemotherapy status and the SUVmax (p &amp;lt; 0.001) of breast tumors. Pre Neoadjuvant (mean SUVmax, 11.4) demonstrated a significantly higher SUVmax than did post 2 cycles tumors (median SUV, 4.7) (p= 0.025). No statistical significant difference was found for SUVmax of post-2 cycles vs. post lesions with a mean SUVmax of 4.7 and 3.9 (p=0.25) respectively. A statistically significant difference was found for volume measurement of pre vs. post-2 cycles vs post Neoadjuvant therapy lesions. A clear qualitative difference by three different observers has been reported among dbPET and MRI volume characterization. A 21% of volume (measurement) discrepancies was found, always with a volume over-estimation by magnetic resonance (structural vs functional imaging). An exquisite -and unexpected- millimetric correlation with post-surgical pathology at the end of neoadjuvant theraphy has been found in dbPET images. Conclusions: dbPET MAMMI has proven to be an excellent tool for quantification, 3D spatial localization and monitoring of neoadjuvant therapy, showing, thanks to its functional nature, earlier and better precision and accuracy than conventional techniques (MRI). Post 2-cycle and Post Neodayuvant Chemotherapy breast cancer tumors consistently display lower 18FDG uptake than pre treatment tumors when treatment is successful. This data suggest that SUVmax measurements of 18FDG-dedicated breast PET can provide valuable information about therapy efficiency. Such an association might be of relevant importance to treatment continuity or adjustement. Citation Format: Michel Herranz, Ines Dominguez, Alvaro Ruibal, Elena Brozos, Sze Yiun Teo, Carmela Rodriguez, Jasper Chaal, Maria Teresa Curiel, Juan Cueva, Beatriz Fernandez, Gabriel G Pavón, Marielle Fortier, Rafael Lopez. Dedicated breast PET (dbPET) a unique functional new tool to accurate quantify response to neoadjuvant therapy in breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-11-11.

Proximity induced vortices and long-range triplet supercurrents in ferromagnetic Josephson junctions and spin valves

Using a spin-parameterized quasiclassical Keldysh-Usadel technique, we theoretically study supercurrent transport in several types of diffusive ferromagnetic (F)/superconducting (S) configurations with differing magnetization textures. We separate out the even- and odd-frequency components of the supercurrent within the low proximity limit and identify the relative contributions from the singlet and triplet channels. We first consider inhomogeneous one-dimensional Josephson structures consisting of a uniform bilayer magnetic S/F/F/S structure and a trilayer S/F/F/F/S configuration, in which case the outer F layers can have either a uniform or conical texture relative to the central uniform F layer. Our results demonstrate that for supercurrents flowing perpendicular to the F/F interfaces, incorporating a conical texture yields the most effective way to observe the signatures of long-ranged spin-triplet supercurrents. We also consider three different types of finite-sized two-dimensional magnetic structures subjected to an applied magnetic field normal to the junction plane: a S/F/S junction with uniform magnetization texture and two S/F/F/S configurations with differing F/F bilayer arrangements. In one case, the F/F interface is parallel with the S/F junction interfaces while in the other case, the F/F junction is oriented perpendicular to the S/F interfaces. We then discuss the proximity vortices and corresponding spatial maps of currents inside the junctions. For the uniform S/F/S junction, we analytically calculate the magnetic field induced supercurrent and pair potential in both the narrow and wide junction regimes, thus providing insight into the variations in the Fraunhofer diffraction patterns and proximity vortices when transitioning from a wide junction to a narrow one. Our extensive computations demonstrate that the induced long-range spin-triplet supercurrents can deeply penetrate uniform F/F bilayers when spin-singlet supercurrents flow parallel to the F/F interfaces. This is in stark contrast to configurations where a spin-singlet supercurrent flows perpendicular to the F/F interfaces. We pinpoint the origin of the induced triplet and singlet correlations through spatial profiles of the decomposed total supercurrents. We find that the penetration of the long-range spin-triplet supercurrents associated with supercurrents flowing parallel to the F/F interfaces is more pronounced when the thicknesses of the F strips are unequal. Finally, if one of the S terminals is replaced with a finite-sized normal metal, we demonstrate that the corresponding experimentally accessible S/F/F/N spin valve presents an effective platform in which the predicted long-range effects can be effectively generated and probed.

Anatomic relationship of the proximal nail matrix to the extensor hallucis longus tendon insertion.

The purpose of this study was to delineate the relationship of the terminal extensor hallucis longus tendon insertion to the proximal limit of the nail matrix of the great toe. Fifty fresh-frozen human cadaver great toes with no evidence of trauma (average age, 62.5years; 29 males and 21 females) were used for this study. Under 25X magnification, the proximal limit of the nail matrix and the terminal bony insertion of the extensor hallucis longus tendons were identified. The distance from the terminal tendon insertion to the nail matrix was ascertained using precision calipers, an optical microscope, and autocad(®) software for windows. Twenty-five great toes were placed in a neutral formalin solution and further analysed by histological longitudinal-sections. The specimens were stained with haematoxylin and eosin and examined microscopically to determine the presence of the extensor hallucis longus tendon along the dorsal aspect of the distal phalanx of each great toe. The main result we found in great toes was that the extensor tendon is between the matrix and the phalanx and extends dorsally to the distal aspect of the distal phalanx in all, 100%, specimens. The nail matrix of the great toe is not attached to the periosteum of the dorsal aspect of the base of the distal phalanx as is the case for fingers, because the extensor hallucis tendon is plantar or directly underneath the nail matrix and the tendon is dorsal to the bone. We have found that the extensor tendon is between the matrix and the phalanx and extends dorsally to the distal aspect of the distal phalanx. The nail matrix of the great toe is not attached to the periosteum of the dorsal aspect of the base of distal phalanx as is the case in fingers, because the extensor hallucis tendon is plantar or directly underneath the nail matrix and the tendon is dorsal to the bone. Our anatomic study demonstrates that the proximal limit of the matrix and nail bed of the human great toe are dorsal and overlapping the terminal extensor hallucis longus tendon until its distal bony insertion in all specimens.

Last interglacial vegetation and climate history from the Portuguese coast

ABSTRACTWe examine the Atlantic maritime vegetation history from Praia Rei Cortiço, Portugal, to understand natural vegetation patterns and infer climatic conditions during the transition from the last interglacial to early glacial periods. Optically stimulated luminescence dating of quartz grains from sediments surrounding the 1.3‐m‐thick organic deposit date the section to within 120–89 ka. Pollen data were used to reconstruct the vegetation history and determine a range of possible past climates using an ensemble of seven modern analogue approaches. A five‐part environmental sequence transitioned from heath‐pine‐dominated communities, deciduous hardwood forests and pine forests to heathlands surrounded by steppe‐like environments. Mixed temperate and Mediterranean forest elements existed during the last interglacial period at Praia Rei Cortiço, suggesting a proximal limit to these floras. Abundant Fagus pollen (&gt;6%) suggests local beech populations existed within maritime forests of the Iberian Atlantic margin, representing a greater distribution of this genus during interglacial periods than has previously been recognized. Climate reconstructions indicate that variations in moisture availability may have been a major driver of the observed environmental changes.

Study of anatomical variation and branching pattern of the femoral nerve in 25 cadavers

Backgrouns: Femoral nerve is used for nerve block in several surgeries. The knowledge of femoral nerve in thigh is important for anatomist, anesthetics, and surgeons to prevent iatrogenic femoral nerve palsy. We dissected 25 human cadavers to study the anatomy of femoral nerve. We dissected the femoral nerve bilaterally in Anatomy Department of Smt N H L Municipal Medical College, and recorded the branching pattern of femoral nerve with digital photography. Objective: To highlight the variation in branching pattern of the femoral nerve. Materials and Methods: We measured the distance from the anterior superior iliac spine (ASIS) to the pubic symphysis bilaterally on each cadaver as an anatomical landmark. We located the femoral nerve through transverse incisions from the ASIS to the pubic symphysis and incisions originating from the midpoint between the ASIS and the pubic symphysis extending longitudinally to the patella. We chose the inguinal ligament as a proximal limitation for dissection of the femoral nerve in the thigh. The distance from the inguinal ligament to the first branching point of the femoral nerve was measured. We traced and dissected all femoral nerve branches to the insertion points. Result: The mean medial–lateral distance from the ASIS to the pubic symphysis was 14.50 ± 1.34 cm (range 13–16). We found the femoral nerve near the midpoint, 46± 5% from the ASIS. We did not measure in cadaver specimen 5 since bony landmarks were difficult to palpate because of excessive adipose tissue. The distance from the inguinal ligament to the first branching point of the femoral nerve was 1.50 ± 0.47 cm (range 1–2cm). Conclusion: The anatomy and morphology we observed remained consistent with the established literature, suggesting that our chosen specimens did not differ from the standard population and that we may consider the results representative of the general population.

Long-range triplet supercurrents induced by singlet supercurrents parallel to magnetic interfaces

Employing a spin-parameterized Keldysh-Usadel technique for the diffusive regime, we demonstrate that even in the low proximity limit, considerable long-ranged triplet supercurrents can be effectively generated by spin-singlet supercurrents flowing parallel to the interfaces of uniform double ferromagnet interlayers with noncollinear exchange fields independent of actual junction geometry. The triplet supercurrents are found to be most pronounced when the thicknesses of the ferromagnet strips are unequal. To experimentally verify this generic phenomenon, we propose an accessible and controllable structure that can fully isolate the long-range triplet effects.

Laparoscopic Discoid Anterior Rectal Excision with the Circular Stapler for Rectosigmoid Endometriosis, Performed by the Gynecologic Surgeon

Study ObjectiveTo demonstrate the technique of laparoscopic discoid anterior rectal wall resection using a circular stapler, feasible in the case of rectosigmoid endometriosis lesions measuring ≤3 cm. DesignCase report (Canadian Task Force classification III). SettingPrivate practice hospital in São Paulo, Brazil. PatientThirty-four-year-old woman with pelvic deep endometriosis including a 2-cm lesion in the rectosigmoid situated 11 cm proximally to the anal border. She had chronic pelvic pain, dysmenorrhea, dyspareunia, and constipation. She had undergone no previous surgical procedures. InterventionsStandard 4-puncture laparoscopy was performed, and all visible endometriosis lesions were first removed before proceeding to rectal resection. The avascular rectovaginal space was identified, and the rectosigmoid was mobilized cranially, releasing the vagina and increasing the final distance of the bowel anastomosis to the anal border. The rectosigmoid nodule was isolated in its entire circumference and remained restricted to the anterior wall of the bowel. It was then transfixed using a 2-0 polyglycolic suture, with the healthy proximal and distal limits of the bowel included in the suture. A 33-cm endoscopic circular stapler was introduced via the anus up to the distal limit of the lesion and opened inside the bowel lumen. By pulling the edges of the suture, the rectosigmoid nodule was introduced inside of the circular stapler. It was fired to resect the anterior rectal wall, and the anastomosis was situated at the anterior and lateral walls of the bowel. Integrity of the bowel was checked via infusion of saline solution with methylene blue dye. Gynecologic surgeons performed all of the procedures. Measurements and Main ResultsBowel resection took 20 minutes, and the entire surgical procedure lasted 120 minutes. The patient was discharged after 48 hours. There were no intercurrent events, either early or late postoperatively. The patient was symptom-free at 2 years of follow-up. ConclusionLaparoscopic discoid excision of an anterior rectal nodule using the circular stapler is an effective option for treating selected cases of rectosigmoid endometriosis. The technique might be reproducible by gynecologic surgeons after proper training.

Anatomic Localization of Motor Points of Wrist Flexors

The aim of this study was to determine the location of the motor points and the intramuscular branches of the wrist flexors in relation to bony landmarks. Sixteen limbs from eight adult cadavers were anatomically dissected. The motor branch points of the flexor carpi radialis and flexor carpi ulnaris muscles and the proximal limit points and the distal limit points in relation to a reference line connecting the medial epicondyle and the pisiform bone or one connecting the medial epicondyle and the base of the second metarcarpal bone were identified. For the flexor carpi radialis muscles, the motor branch points were located at a distance of 27% ± 6% of the reference line, whereas the proximal limit points and the distal limit points were located at a distance of 21% ± 5% and 37% ± 8% of the reference line. For the flexor carpi ulnaris muscles, the corresponding data were 32% ± 8%, 23% ± 6%, and 43% ± 9%. The results may assist in enhancing accuracy when localizing points for neuromuscular blockade of the wrist flexors. The optimal area for flexor carpi radialis muscle injection is at a quarter point and that for flexor carpi ulnaris muscle injection is at one-third point along each reference line from the medial epicondyle.

V2-03 THE MALONE MEATOPLASTY: A DORSAL APPROACH TO MEATAL STENOSIS IN PATIENTS WITH LICHEN SCLEROSUS

INTRODUCTION AND OBJECTIVES: The treatment of meatal stenosis associated with lichen sclerosus is traditionally treated either by meatal dilatation or ventral meatotomy. These operations have high recurrence rates or create a hypospadiac meatus. We present an established technique in the use of a dorsal approach. METHODS: Initially a small ventral meatotomy is performed. The epithelium of the urethra and glans is opposed with 3, 6-zero polyglactin (PG) sutures. This acts to widen the meatus slightly without making it hypospadiac but more importantly it allows the insertion of forceps to assess and ensure that the stricture does not extend significantly into the navicular fossa. Next a deeper dorsal meatotomy is performed. Again the epithelium of the urethra/glans are opposed. The combination of small ventral and deeper dorsal meatotomies should completely open the stenosed meatus but the cosmetic appearance at this stage is poor since the sutures of the dorsal meatotomy pucker the glans due to the thickness of the corpus spongiosum. This is overcome by an inverted V-shaped relieving incision with the apex of the V close to the proximal limit of the dorsal meatotomy. The edges of the relieving incision are freed by sharp dissection. The opposing left and right inner edges are closed with continuous PG to form the roof of the distal neourethra. The outer glans layer is opposed with interrupted PG. RESULTS: The final result is a slit-like but good calibre meatus at the tip of the glans. CONCLUSIONS: During a follow-up of 4.2 years there were recurrences in 6/116 patients, 5 of whom required re-operation (4.3%). 93% patients were either happy or very happy with the cosmetic result. Conclusion: This technique can achieve excellent aesthetic results, with low incidence of a spraying stream.

Review on novel concepts of columnar lined esophagus

Columnar lined esophagus (CLE) is a marker for gastroesophageal reflux and associates with an increased cancer risk among those with Barrett's esophagus. Recent studies fostered the development of integrated CLE concepts. Using PubMed, we conducted a review of studies on novel histopathological concepts of nondysplastic CLE. Two histopathological concepts-the squamo-oxyntic gap (SOG) and the dilated distal esophagus (DDE), currently model our novel understanding of CLE. As a consequence of reflux, SOG interposes between the squamous lined esophagus and the oxyntic mucosa of the proximal stomach. Thus the SOG describes the histopathology of CLE within the tubular esophagus and the DDE, which is known to develop at the cost of a shortened lower esophageal sphincter and foster increased acid gastric reflux. Histopathological studies of the lower end of the esophagus indicate, that the DDE is reflux damaged, dilated, gastric type folds forming esophagus and cannot be differentiated from proximal stomach by endoscopy. While the endoscopically visible squamocolumnar junction (SCJ) defines the proximal limit of the SOG, the assessment of the distal limit requires the histopathology of measured multilevel biopsies. Within the SOG, CLE types distribute along a distinct zonation with intestinal metaplasia (IM; Barrett's esophagus) and/or cardiac mucosa (CM) at the SCJ and oxyntocardiac mucosa (OCM) within the distal portion of the SOG. The zonation follows the pH-gradient across the distal esophagus. Diagnosis of SOG and DDE includes endoscopy, histopathology of measured multi-level biopsies from the distal esophagus, function, and radiologic tests. CM and OCM do not require treatment and are surveilled in 5 year intervals, unless they associate with life quality impairing symptoms, which demand medical or surgical therapy. In the presence of an increased cancer risk profile, it is justified to consider radiofrequency ablation (RFA) of IM within clinical studies in order to prevent the progression to dysplasia and cancer. Dysplasia justifies RFA ± endoscopic resection. SOG and DDE represent novel concepts fusing the morphological and functional aspects of CLE. Future studies should examine the impact of SOG and DDE for monitoring and management of gastroesophageal reflux disease (GERD).

Target refractions in bilateral monofocal pseudophakia: analysis of a mathematical model

A recent paper proposes a model for suitable target refractions for monofocal pseudophakic monovision. The purpose of this paper is to examine the mathematics that underpins the theory. The expressions for the optimal target refractions presented before are shown formally to define the minimum of the mean binocular refractive error over a range of object distances. The model is shown to be much more sensitive to errors in the distal target refraction than to errors in the proximal refraction. It is also more sensitive to the choice of proximal limit of the object range than to the distal limit. These considerations are important in selecting and evaluating suitable combinations of refractions in pseudophakic monovision. (S Afr Optom 2013 72(3) 103-109)

The dilemma of controlling cultural eutrophication of lakes

The management of eutrophication has been impeded by reliance on short-term experimental additions of nutrients to bottles and mesocosms. These measures of proximate nutrient limitation fail to account for the gradual changes in biogeochemical nutrient cycles and nutrient fluxes from sediments, and succession of communities that are important components of whole-ecosystem responses. Erroneous assumptions about ecosystem processes and lack of accounting for hysteresis during lake recovery have further confused management of eutrophication. I conclude that long-term, whole-ecosystem experiments and case histories of lake recovery provide the only reliable evidence for policies to reduce eutrophication. The only method that has had proven success in reducing the eutrophication of lakes is reducing input of phosphorus. There are no case histories or long-term ecosystem-scale experiments to support recent claims that to reduce eutrophication of lakes, nitrogen must be controlled instead of or in addition to phosphorus. Before expensive policies to reduce nitrogen input are implemented, they require ecosystem-scale verification. The recent claim that the ‘phosphorus paradigm’ for recovering lakes from eutrophication has been ‘eroded’ has no basis. Instead, the case for phosphorus control has been strengthened by numerous case histories and large-scale experiments spanning several decades.