Effect of compressive follower preload on the flexion-extension response of the human lumbar spine.

Traditional experimental methods are unable to study the kinematics of whole lumbar spine specimens under physiologic compressive preloads because the spine without active musculature buckles under just 120 N of vertical load. However, the lumbar spine can support a compressive load of physiologic magnitude (up to 1200 N) without collapsing if the load is applied along a follower load path. This study tested the hypothesis that the load-displacement response of the lumbar spine in flexion-extension is affected by the magnitude of the follower preload and the follower preload path. Twenty-one fresh human cadaveric lumbar spines were tested in flexion-extension under increasing compressive follower preload applied along two distinctly different optimized preload paths. The first (neutral) preload path was considered optimum if the specimen underwent the least angular change in its lordosis when the full range of preload (0-1200 N) was applied in its neutral posture. The second (flexed) preload path was optimized for an intermediate specimen posture between neutral and full flexion. A twofold increase in flexion stiffness occurred around the neutral posture as the preload was increased from 0 to 1200 N. The preload magnitude (400 N and larger) significantly affected the range of motion (ROM), with a 25% decrease at 1200 N preload applied along the neutral path. When the preload was applied along a path optimized for an intermediate forward-flexed posture, only a 15% decrease in ROM occurred at 1200 N. The results demonstrate that whole lumbar spine specimens can be subjected to compressive follower preloads of in vivo magnitudes while allowing physiologic mobility under flexion-extension moments. The optimized follower preload provides a method to simulate the resultant vector of the muscles that allow the spine to support physiologic compressive loads induced during flexion-extension activities.     

Aprotinin reduces oxidative stress induced by pneumoperitoneum in rats

Background

Ischemia–reperfusion injury induced by pneumoperitoneum is a well-studied entity, which increases oxidative stress during laparoscopic operations. The reported anti-inflammatory action of aprotinin was measured in a pneumoperitoneum model in rats for the first time in this study.

Materials and methods

A total of 60 male Albino Wistar rats were used in our protocol. Prolonged pneumoperitoneum (4 h) was applied, causing splanchnic ischemia and a period of reperfusion with a duration of 60 or 180 min followed. Several cytokines and markers of oxidative stress were measured in liver, small intestine, and lungs to compare the aprotinin group with the control group. Tissue inflammation was also evaluated and compared between groups using a five-scaled histopathologic score.

Results

In aprotinin group values of biochemical markers (tumor necrosis factor α, interleukin 6, endothelin 1, C reactive protein, pro-oxidant–antioxidant balance, and carbonyl proteins) were lower in all tissues studied. Statistical significance was greater in liver and lungs (P < 0.05). Histopathologic examination revealed significant difference between control and aprotinin groups in all tissues examined. Aprotinin groups showed mild to moderate lesions, while in control groups severe to very severe inflammation was present. Aprotinin subgroup with prolonged reperfusion period (180 min) showed milder lesions in all tissues than the rest of the groups.

Conclusions

Aprotinin reduced inflammatory response and oxidative stress induced by pneumoperitoneum in liver, small intestine, and lungs.     

Physical activity and sedentary behavior thresholds for identifying childhood hypertension and its phenotypes: The Healthy Growth Study

Hypertension phenotypes may represent differential pathophysiologic mechanisms and clinical impact, yet they have been poorly investigated. The study aimed to examine the associations of physical activity and sedentary behavior with hypertension phenotypes in a large group of Greek children and to identify thresholds regarding risk of hypertension. This was a cross-sectional study with a regionally representative sample of 2473 schoolchildren aged 9–13 years, with full data on physical activity and sedentary behavior indices, as well as arterial blood pressure measurements, physical examination, and anthropometry. Hypertensive children of both sexes had lower levels of physical activity (steps/d). Hypertensive girls had lower moderate-to-vigorous physical activity (MVPA), whereas hypertensive boys with isolated systolic hypertension (ISH) had more screen time than their normotensive counterparts. Increased levels of physical activity was associated with 33%–54% lower risk of all hypertension phenotypes in both sexes, whereas increased MVPA was associated with 41%–65% lower risk of all phenotypes in girls and with ISH and systolic and diastolic hypertension (SDH) in boys. In boys, higher sedentary time was associated with 11%–13% higher risk for SDH and ISH. Cutoff points of 12,378 steps/d, 47.3 min/d of MVPA, and 2.9 h/d of sedentary behavior were determined for identifying children at increased risk of hypertension. Physical activity is inversely associated with all hypertension phenotypes, whereas sedentary behavior is positively associated with ISH and SDH in boys. More studies should confirm the hypertension-specific cutoff values identified to be used in future prevention programs for childhood hypertension.     

Obturator hernia revisited: surgical anatomy, embryology, diagnosis, and technique of repair

Obturator hernia is the protrusion of intraperitoneal or extraperitoneal organs or tissues through the obturator canal. The first case was published by de Ronsil in 1724. Obturator hernia is more common in older malnourished women due to loss of supporting connective tissue and the wider female pelvis. The hernia sac usually contains small bowel, especially ileum. It may follow the anterior or posterior division of the obturator nerve. In most cases, obturator hernia presents with intestinal obstruction of unknown cause. It may present with obturator neuralgia, as a palpable mass or, in cases of bowel necrosis, as ecchymosis of the thigh. A correct diagnosis is made in 20 to 30 per cent of cases. CT scan is considered the gold standard for diagnosis, whereas ultrasonography, contrast studies, herniography and plain films are less specific. Surgery is the only treatment option for obturator hernia. Hesitancy to intervene surgically for chronically ill patients results in high mortality. Transabdominal approach is indicated in cases of complete bowel obstruction or suspected peritonitis. The extra-abdominal approach is used in preoperatively diagnosed cases and in absence of bowel strangulation. The laparoscopic approach is minimally invasive and effectively reduces morbidity. The defect is closed using sutures, tissue flaps, or prosthetic mesh.     

Characteristics of patients with stage T1b incidental prostate cancer

OBJECTIVE: To study the characteristics of patients with incidental prostate cancer. MATERIAL AND METHODS: The proportion of incidentally diagnosed prostate cancer was investigated in patients who underwent transurethral resection of the prostate (TURP) at our clinic over a 5-year period. "True" incidental prostate cancer was defined as cases where the preoperative digital rectal examination (DRE) and the prostate-specific antigen (PSA) value were normal. Patients with known malignancy of the prostate were excluded, together with those with PSA >4 ng/ml and/or a positive DRE. The characteristics of these patients were compared to those of benign prostatic hyperplasia patients and the group as a whole. RESULTS: Of the 786 patients operated on between 1999 and 2003, 34 (4.3%) had a positive pathology report for "true" incidental prostate cancer. An increased frequency of poorly differentiated tumors (32.3%) was noted. Of the 34 patients, 17 were stage T1a and 17 T1b; 11 patients had a Gleason sum of 7-10, all of them in the T1b group. In the T1b group the mean age was 74 years, the mean PSA level 2.9 ng/ml and the mean weight of tissue resected 11.1 g. Corresponding values in the T1a patients were 70.1 years, 3.32 ng/ml and 18.2 g. CONCLUSIONS: Compared to previous studies, we noticed a low incidence of "true" incidental prostatic carcinoma but a high ratio of poorly differentiated tumors (all stage T1b). Compared to the group as a whole, patients with incidental prostate cancer were older and had smaller prostate and transition zone volumes. Further research is needed to identify parameters that may aid in the earlier identification of incidental prostate cancer, as patients may benefit from curative treatment.     

A prospective study comparing diathermy and scalpel incisions in tension-free inguinal hernioplasty

Although still controversial, the use of diathermy instead of scalpel for skin incision and underlying tissue dissection is gradually gaining wide acceptance. This is due to the observation that no change in wound complication rates or postoperative pain are reported with the use of electrocautery. However, these studies include operations without the use of prosthetic materials during abdominal wall closure. The purpose of this study was to investigate the hypothesis that a) application of extreme heat may result in significant postoperative pain and poor wound healing because of excessive tissue damage and scarring respectively, and b) skin incision with the use of diathermy entails increased risk of wound infection in the presence of an underlying prosthetic material. One hundred twenty-five consecutive patients submitted to inguinal hernioplasty using the tension-free technique and fulfilling the inclusion criteria for the study were allocated alternately to either scalpel (n = 60), or diathermy (n = 57) groups. Eight patients had bilateral hernias. Five of them were allocated to the scalpel group and three to the diathermy group. According to the study protocol, they received both approaches for skin and underlying tissues incision, thus resulting in a total of 68 scalpel and 65 diathermy individual hernioplasties. Parameters measured included blood loss during the skin incision and underlying tissue dissection, postoperative pain and requirements for analgesics, the presence of wound dehiscence in the absence of infection, and postoperative wound infection on the day of discharge, on the day staples were removed, and 1 month after surgery. The two groups of patients were similar in relation to patient demographics, type of hernias, and operation details. Blood loss was minimal, and the amount of blood lost did not differ between the two groups. Diathermy group patients required less parenteral analgesics on the first postoperative day. A higher proportion of patients in the scalpel group continued to need oral analgesics on the second postoperative day compared to patients in the diathermy group. There was no difference between the two groups in terms of wound strength. Infectious complications were totally absent. The use of diathermy for skin incision during inguinal hernioplasty is as safe as the use of scalpel in terms of wound healing and reduces the analgesics requirements in the postoperative period.