Surgeon Upper Extremity Kinematics During Error and Error-Free Retropubic Trocar Passage

INTRODUCTION AND HYPOTHESIS

Surgeon kinematics play a significant role in the prevention of patient injury. We hypothesized that elbow extension and ulnar wrist deviation are associated with bladder injury during simulated midurethral sling (MUS) procedures.

METHODS

We used motion capture technology to measure surgeons' flexion/extension, abduction/adduction, and internal/external rotation angular time series for shoulder, elbow, and wrist joints. Starting and ending angles, minimum and maximum angles, and range of motion (ROM) were extracted from each time series. We created anatomical multibody models and applied linear mixed modeling to compare kinematics between trials with versus without bladder penetration and attending versus resident surgeons. A total of 32 trials would provide 90% power to detect a difference.

RESULTS

Out of 85 passes, 62 were posterior to the suprapubic bone and 20 penetrated the bladder. Trials with versus without bladder penetration were associated with more initial wrist dorsiflexion (-27.32 vs -9.03°, p = 0.01), less final elbow flexion (39.49 vs 60.81, p = 0.03), and greater ROM in both the wrist (27.48 vs 14.01, p = 0.02), and elbow (20.45 vs 12.87, p = 0.04). Wrist deviation and arm pronation were not associated with bladder penetration. Compared with attendings, residents had more ROM in elbow flexion (14.61 vs 8.35°, p < 0.01), but less ROM in wrist dorsiflexion (13.31 vs 20.33, p = 0.02) and arm pronation (4.75 vs 38.46, p < 0.01).

CONCLUSIONS

Bladder penetration during MUS is associated with wrist dorsiflexion and elbow flexion but not internal wrist deviation and arm supination. Attending surgeons exerted control with the wrist and forearm, surgical trainees with the elbow. Our findings have direct implications for MUS teaching.

Cognitive models for mentally visualizing a sharp instrument in a blind procedure

Purpose

Our objective was to understand the cognitive strategies used by surgeons to mentally visualize navigation of a surgical instrument through blind space.

Methods

We conducted semi-structured interviews with 15 expert and novice surgeons following simulated retropubic trocar passage on 3D-printed models of pelvises segmented from preop MRIs. Midurethral sling surgery involves blind passage of a trocar among the urethra, bladder, iliac vessels, and bowel while relying primarily on haptic feedback from the suprapubic bone (SPB) for guidance. Our conceptual foundation was based on Lahav's study on blind people's mental mapping of spaces using haptic cues. Participants detailed how they mentally pictured the trocar's location relative to vital anatomy. We coded all responses and used constant comparative analysis to generate themes, confirmed with member checking.

Results

Expert and novice participants utilized multiple cognitive strategies combined with haptic feedback to accomplish safe trocar passage. Some used a step-by-step route strategy, visualizing sequential 2D axial images of anatomy adjacent to the SPB. Others used a map strategy, forming global 3D pictures. Although these mental pictures vanished when they were "lost," a safe zone could be reestablished by touching the SPB. Experts were more likely to relate their body position to the trocar path and rely on minor variations in resistance. Novices were more inclined toward backtracking of the trocar.

Conclusions

Our findings may be extended to any blind surgical procedure. Teaching visualization strategies and incorporating tactile feedback can be used intraoperatively to help learners navigate their instrument safely around vital organs.

Surgeon estimation of retropubic trocar position in blind 3D space

INTRODUCTION AND HYPOTHESIS

Retropubic midurethral sling surgery involves the blind passage of trocars near vital organs. We quantified the proximity of surgeons' mental representation of trocar position relative to actual position using a pelvis simulation platform. We hypothesized that novice surgeons, compared with experts, would estimate the trocar's location to be further from the actual location.

METHODS

Novice and expert surgeons performed bilateral retropubic trocar passes of a Gynecare TVT trocar (#810041B-#810,051) on the simulation platform. We measured the trocar tip's position using a motion capture system, and recorded vocalizations when they perceived contacting the bone and crossing three landmark-oriented planes. We calculated differences (∆Bone, ∆Turn, ∆Top, ∆Pop) between vocalization times and when the trocar crossed the corresponding plane. We performed Mann-Whitney and Chi-squared tests to investigate differences between novices and experts and Levene's test to assess equality of variances for subject-level variation.

RESULTS

A total of 34 trials, including 22 expert and 12 novice trials, were performed by six participants. ∆Bone was significantly smaller among novice surgeons (1.27 vs 2.81 s, p=0.013). There were no significant differences in the remaining three deltas or in vocalizing early versus late. Levene's test revealed no significant differences in within-subject variability for any of the four deltas. Novices passed the trocar anterior to the pubic bone on three passes.

CONCLUSIONS

Novices were similar to expert surgeons in their estimation of the trocar's location and may have relied more heavily on anticipatory mechanisms to compensate for lack of experience. Teaching surgeons should make sure the novice surgeon trocar pass starts posterior to the bone.

Retropubic trocar modified with a load cell to verify contact with pubic bone

BACKGROUND

Vital injuries during midurethral sling surgery are avoided by maintaining constant trocar contact with bone, and yet this is challenging for a teaching surgeon to monitor during this blind procedure. We modified a retropubic trocar with a load cell to distinguish on-bone and off-bone movement and tested it on a midurethral sling surgery 3-dimensional surgery simulator.

METHODS

Two experts and 3 novice surgeons performed retropubic trocar passage on the physical pelvic floor model using the modified trocar. Biofidelity was assessed comparing expert performance on a Thiel-embalmed cadaver and the physical model. The test-retest was assessed comparing performance on the physical pelvic model 2 weeks apart. The force variables were analyzed with paired and independent t tests. We performed post hoc analyses comparing the experts to novices on the physical model.

RESULTS

The root-mean-squared force was similar between the cadaver and model (24.3 vs 21.1 pounds, P = .62), suggesting biofidelity. Root-mean-squared force was also similar between the test and retest (14.0 vs 19.1 pounds, P =. 30). The expert surgeons exhibited a larger maximum force amplitude (51.2 vs 22.7 pounds, P = .03), shorter time to maximum force (2.7 vs 9.5 seconds, P = .03) and larger maximum rate of force development (171.5 vs 54.0 pounds/second, P = .01).

CONCLUSION

This study suggested high test-retest reliability and adequate biofidelity of the modified trocar used on our midurethral sling surgery 3-dimensional surgery simulator. This innovative trocar can be used both in simulation and in the operating room to help the novice surgeons stay on the bone and to help the attending surgeon monitor safe surgery.

Abscisic acid, cold and salt stimulate conserved metabolic regulation in the moss Physcomitrella patens

Salt and cold are major abiotic stresses that have adverse effects on plant growth and development. To cope with these stresses and their detrimental effects plants have evolved several metabolic, biochemical and physiological processes that are mainly triggered and mediated by the plant hormone abscisic acid (ABA). To elucidate the metabolic responses of the moss Physcomitrella patens, which serves as a model plant for abiotic stress adaptation, we performed GC-MS-based metabolic profiling of plants challenged for 5 and 28 h with either salt, cold or ABA. Our results indicate significant changes in the accumulation of several sugars including maltose, isomaltose and trehalose, amino acids including arginine, histidine, ornithine, tryptophan and tyrosine, and organic acids mainly citric acid and malonic acid. The metabolic responses provoked by ABA, cold and salt show considerable similarities. The accumulation of certain metabolites positively correlates with gene expression data whereas some metabolites do not show correlation with cognate transcript abundance. To place our results into an evolutionary context we compared the ABA- and stress-induced metabolic changes in moss to available metabolic profiles of the seed plant Arabidopsis thaliana. We detected considerable conservation between the species, indicating early evolution of stress-associated metabolic adaptations that probably occurred at the plant water-to-land transition.

Multidrug therapy in leprosy

Leprosy is an ancient disease, which was treated by local application of chaulmoogra/hydnocarpus oil during prechemotherapeutic era. Since 1940, dapsone was the only chemotherapeutic agent used for treatment of leprosy for about three decades. Prolonged, interrupted and inadequate use of dapsone monotherapy, leads to development of dapsone-resistant cases. Usefulness of clofazimine was known in 1962. Introduction of rifampicin--a powerful bactericidal drug in 1970 has opened the avenues of multidrug therapy to treat leprosy. Multidrug therapy recommended by World Health Organisation came into practice after 1982. The regimen followed now is for duration of 6 months in paucibacillary and for the duration of 12 months in multibacillary cases. It is proven to be safe and effective. Multidrug therapy for leprosy cases is available in the form of blister calender packs and is available free of cost at all government health facilities. Although more new drugs such as ofloxacin, minocyclin, clarithromycin, etc, are known now but they are used as alternative drugs if a component of combination in multidrug therapy becomes contra-indicated. This article brings the details of various drugs used under multidrug therapy, their characteristics, side-effects, regimens and alternative drugs available for treating leprosy.

Progress towards elimination of leprosy as a public health problem in India and role of modified leprosy elimination campaign

India (population 943 million) has seen a highly significant decrease in the prevalence of leprosy since the introduction of multi-drug therapy (MDT) in 1981. From a prevalence rate of 57/10,000 of the population in March 1981, the figure has declined to 5.2/10,000 in March 1999. This was possible due to the creation of a completely vertical (specialized) infrastructure for leprosy control in the 218 endemic districts of the country and skeleton vertical staff in the remaining districts, coupled with the recruitment of additional staff on contract basis to provide MDT through vertical staff in endemic districts and mobile treatment units in the moderate and low endemic districts. Despite all efforts, however, new case detection has not shown a decline over the last 14 years due to the presence of hidden (and undiagnosed) cases. Therefore, in order to intensify and hasten progress towards elimination (less than 1 case per 10,000 of the population) in the whole country, it was decided to implement a massive leprosy elimination campaign (LEC) in all the States/Union Territories (UTs). The reports of 22 States/UTs indicate that 415 out of the total of 490 districts in the country were covered by modified LEC (MLEC), with 85% coverage of the population. The campaign used in India was modified from the pattern previously described by the World Health Organization. The detection of hidden or suspected cases took place within a short, intensive period of 6-7 days and relied heavily on house-to-house searches by General Health Care staff trained in leprosy detection and confirmation was made by appropriately trained staff. This MLEC received widespread Government and public support, resulting in the detection of 454,290 hidden cases of leprosy, whilst providing training to a large number of General Health Care staff and volunteers and creating widespread awareness about leprosy and the availability of treatment free of charge for all cases. This programme proved to be one of the most successful health care interventions undertaken in India in recent years, particularly in the states of Bihar and Orissa. Although a few states in India are unlikely to reach the current WHO goal of elimination before end of the year 2000, the results of the MLEC strongly support the possibility that elimination levels will be achieved in the majority of states by the end of the year 2000 and at national level by the end of the year 2002.

Low birthweight babies in the Third World: maternal nursing versus professional nursing care

Severe nursing shortage adds to the high mortality of low birthweight babies in developing countries. To study the efficacy of maternal nursing care we conducted a prospective matched case-control study. Outcome was compared in low birthweight babies nursed by mothers (mothers' group, n = 151, cases), versus professional nurses (nurses' group, n = 211, controls). Irrespective of condition on admission, weight gain was significantly higher (p < 0.001) and overall mortality rate significantly lower (p < 0.001) in the mothers' group. Mortality was also lower in the mothers' group for babies with pathological jaundice, skin/umbilical sepsis, and no disease except low birthweight (p < 0.001). Intercurrent diarrhoea, aspiration pneumonia, and septicaemia did not differ. Training mothers to nurse their low birthweight babies can significantly reduce mortality rates and decrease workload on nurses. Policy formulation using this approach can save costs in developing countries.

Hepatitis A in Saudi Arabia: A comparative sero-epidemiological study

Full text is available as a scanned copy of the original print version.

Maternal sociocultural status: a novel assessment of risk for the birth of small for gestational age, low birth weight infants

OBJECTIVES

We assessed the significance of material sociocultural status within the family as a risk factor for low birth weight-small for gestational age (LBW-SGA) births using a novel scoring system and also isolated related medical risk factors.

METHODS

A prospective matched pairs case control study of 396 LBW-SGA infants (cases) and 396 term, appropriate for gestational age infants (controls) was set up.

RESULTS

Low maternal sociocultural status (p = 0.02) was significantly associated with LBW-SGA births as were nonregistration for antenatal care (p = 0.001), maternal weight at delivery < 50 kg (p < 0.0001), antepartum hemorrhage/preeclampsia (p < 0.01), primigravidity and previous small baby (p <0001). Other risk factors included birth interval < 24 m (p < 0.001) and poor maternal or paternal education (p < 0.05). Conditional logistic regression identified maternal weight at delivery < 50 kg (OR 4.8, 95% C.I. 3.0-7.6), lack of antenatal care (OR 2.0, 95% C.I. 1.4-2.9), antepartum hemorrhage/preeclampsia (OR 4.3, 95% C.I. 1.7-10.8) and previous small baby (OR 4.3, 95% C.I. 2.1-8.9) as independent risk factors.

CONCLUSIONS

Low sociocultural status of the mother within the family is significantly associated with having a LBW-SGA baby. Further studies are warranted to study this risk factor.

Importance of confirmatory testing in donated blood

During the period from January 1995 to January 1996 blood units from 8747 blood donors were screened for blood-borne viruses at King Khalid University Hospital, Riyadh, Saudi Arabia. These tests included HBsAg, antibodies to hepatitis C virus (anti-HCV), antibodies to human immunodeficiency viruses (anti-HIV-1/2). During the same period 1500 blood units were screened for antibodies to human T-cell lymphotropic virus type 1 (anti-HTLV-1). Among the 8747 blood donors, 2.7% were found to be HBsAg-positive on initial screening but 2.2% were confirmed as HBsAg-positive. Regarding HCV, 2.8% were anti-HCV-positive on initial screening but the percentage dropped down to 1.6% on confirmation and only 12 (0.14%) were considered indeterminant by line immunoassay. None of the donors was confirmed anti-HIV- positive but five were diagnosed as indeterminant by western blot. Only four were anti-HTLV- I - positive on initial screening but were diagnosed as indeterminant by western blot. In total, 492 (5.6%) of the blood units tested were reactive for any one of the four viruses on screening but only 327 (3.7%) were confirmed positive. All 492 blood units were not recommended for transfusion. This raises the question of the usefulness of confirmatory testing in blood donation. We believe the confirmation is only important for counseling the donor and a non-reactive result on confirmation should not interfere with the decision of not recommending the blood for transfusion.

Schistosomiasis as a possible risk factor for acquiring hepatitis C virus (HCV) infection among Saudis

BACKGROUND

Risk factors for acquiring hepatitis C virus (HCV) infection have been elucidated in many developed countries but the picture is still not clear in many Middle Eastern Countries including Saudi Arabia.

AIM

To investigate possible risk factors for acquiring HCV among Saudis.

METHODS

Various demographic and medical risk factors that might be associated with the spread of HCV among Saudis were investigated. The population studied included 20 anti-HCV-positive with chronic liver disease (CLD), 30 anti-HCV-positive patients without CLD and 272 anti-HCV-negative Saudi blood donors. All people investigated were of the same age group (>40 years of age).

RESULTS

None of the demographic parameters studied (type of job, type of housing, education) was found to be significantly associated with acquiring HCV infection among our Saudi patients. On the other hand up to 40% of the anti-HCV-positive patients and irrespective of the condition of liver disease had a history of surgery, and 25% of them had a history of multiple injections. Furthermore, at least 20% of our anti-HCV-positive patients had a history of schistosomiasis which is significantly higher than schistosomiasis among the blood donors (P < 0.005).

CONCLUSION

In addition to blood and blood products, schistosomiasis seems to be a possible risk factor for acquiring HCV among the Saudi population. The association between schistosomiasis and enhancement of HCV infection need to be further elucidated.

Sequential use of inactivated poliovirus vaccine followed by oral poliovirus vaccine in Oman

Seroprevalence and geometric mean titers (GMTs) were compared at 6 and 10 months after vaccination with monovalent type 1 oral poliovirus vaccine (OPV) at 6 months and trivalent OPV at 7 and 9 months. Group 1 had received 4 doses of OPV, group 2 OPV at birth and 3 doses of OPV and inactivated poliovirus vaccine (IPV), and group 3 placebo at birth and 3 doses of IPV. A total of 547 infants completed the study. At 10 months, seroprevalence to poliovirus type 1 was 98%, 99%, and 98% in groups 1, 2, and 3; 100%, 100%, and 98% to poliovirus type 2; and 80%, 96%, and 91% to poliovirus type 3. Differences in seroprevalence among the groups were significant for poliovirus type 3 (P < .001). Between 6 and 10 months, significant increases in seroprevalence and GMTs occurred for poliovirus type 1 but not for types 2 and 3. Two OPV doses following 3 IPV doses did not significantly increase seroprevalence or raise GMTs for poliovirus types 2 and 3; however, significant increases were found for poliovirus type 1, which may have benefitted from monovalent type 1 administration.

Synthetic peptides related to laminin pentapeptide (YIGSR) fragment

The synthetic laminin pentapeptide amide fragment (LF), Tyr-Ile-Gly-Ser-Arg-NH2 corresponding to a part of B1 chain of the glycoprotein, laminin, and six of its analogues having structural modifications at positions 1, 3 and 4 were synthesized by solid phase method employing mainly 9-fluorenylmethoxycarbonyl-amino acid trichlorophenyl esters as coupling agents and Merrifield resin as the solid support. Their biological activities were studied in vivo by lung tumor colonization assay and in vitro by cell adhesion assay. The activity of synthetic LF was found to correlate with the earlier reported results in both in vivo and in vitro assays. Among the analogues made, [Tyr4] LF and [Thr4]LF were found to inhibit the lung tumor colonies more efficiently than LF itself in the in vivo assay whereas [D- Ser4]LF exhibited almost the same inhibition as LF.

Prevalence of antibodies to hepatitis C virus among Saudi patients with chronic liver diseases

The prevalence of antibodies against hepatitis C virus (anti-HCV) was determined in 55 patients with chronic liver diseases including liver cirrhosis (42 patients), liver cirrhosis and hepatocellular carcinoma (8 patients), and chronic active hepatitis (4 patients). A total of 63.6% of these patients were positive for anti-HCV, a significantly higher prevalence than the rate of 3.9% observed in 488 asymptomatic volunteers. Of the 42 patients with liver cirrhosis 16 (38.1%) had positive anti-HCV without any markers of hepatitis B virus (HBV), while 12 (28.6%) had markers of neither HCV nor HBV infection. Our findings suggest that HCV infection may play a significant role in the pathogenesis of chronic liver disease in Saudi Arabia, which is an area of endemic HBV infection. Screening for anti HCV should be considered mandatory in patients with chronic liver disease (CLD) especially where the etiology appears obscure.

Studies on malabsorption in malnourished Pakistani children

Malnutrition is a common finding in Pakistan especially in children of low socio-economic class. Impairment of digestion and absorption makes the diet inefficient at fulfilling the requirements of the child and leads to malnutrition. Earlier work from this laboratory has shown that feeding a high-protein diet to children suffering from protein-energy malnutrition (PEM) did not improve their condition. In the present study forty-two malnourished children and seventeen control subjects were investigated. They were divided into five groups, i.e. fibrocystic disease of the pancreas (n = 9), coeliac disease (n = 17), lactose intolerance (n = 5), PEM (n = 5) and nonspecific diarrhoea (n = 6) on the basis of history, clinical impression and biochemical findings. They were from 6 months to 12 years of age. The majority of them were suffering from diarrhoea, distension of the abdomen and retardation of growth. All children were physically examined and anthropometric measurements were recorded. Changes in hair in the form of sparseness, dyspigmentation and easy pluckability were observed in all groups. In PEM, 80% of the cases had enlarged livers. All children had reduced weight and height as compared with the control group. Haemoglobin, total protein and serum albumin showed a decrease and the fall was greatest in PEM cases as compared with the control group. The excretion of alpha-amino nitrogen increased in PEM children while hydroxyproline and creatinine levels showed a decrease as compared with the control group. The hydroxyproline index, which signifies the growth rate, was also significantly lower in all groups. Xylose and lactose tolerance tests were performed after an oral dose of xylose or lactose respectively. The xylose concentration after the test dose was reduced with the lowest values in the coeliac disease group as compared with the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of oral potassium supplements on plasma potassium in normokalaemic and hypokalaemic patients

Thirteen out of 44 patients taking bendrofluazide 10 mg daily became hypokalaemic over a period of three months. Oral potassium supplements of 3.6 grams daily (48 mmol) given in addition to bendrofluazide for a further period of 3 months raised plasma potassium level significantly in hypokalaemic patients only. We conclude that where patients on diuretic therapy are followed up with plasma potassium measurements, it is generally necessary to prescribe oral potassium in the presence of hypokalaemia only.

Aspects of paediatric liver disease in Karachi

Seventy children with hepatomegaly, between the ages of 3 months and 13 years, were investigated including a liver biopsy in 60, to study the general pattern of liver disease in children. Thirty percent had acute viral hapatitis, 20 percent cirrhosis, 17.6 percent pulmonary tuberculosis, 18 percent hereditary diseases and 14 percent miscellaneous diseases involving the liver. None of the cases met the criteria for Indian childhood cirrhosis. It was concluded that in Karachi pulmonary tuberculosis was a common case of hepatosplenomegaly in children and that the aetiology of cirrhosis was probably multifactorial.