Efficacy of incisional negative pressure therapy in preventing post-sternotomy wound complications

BACKGROUND

Sternal wound infections represent a source of significant morbidity and mortality following median sternotomy. The use of incisional negative pressure wound therapy in prevention has yet to be elucidated.

METHODS

A retrospective study was conducted before and after a universal wound care protocol was implemented including the prophylactic use of negative pressure wound therapy (NPWT). The primary endpoint was sternal infections within 90 days of the index operation.

RESULTS

In the control period, there was a 3.0% rate of sternal infection within 90 days compared to 0.8% in the intervention period (p < 0.001). An odds ratio of 0.25 (95% confidence interval 0.11, 0.57; p < 0.001) in the intervention period as compared to the control period was demonstrated.

CONCLUSIONS

The use of a standardized wound care protocol including the universal application of NPWT for patients undergoing cardiac surgery with median sternotomy was an independent predictor of decreased rates of sternal infection.

The effect of anaesthetic use on healing in sub cutaneous abscess management: a retrospective before and after cohort study

INTRODUCTION

There is wide variation in the management of simple subcutaneous abscesses in the UK and no national guidelines describing best practice. During the SARS-CoV-2 pandemic, regional or local anaesthesia (LA) use was recommended instead of general anaesthesia. This study aimed to assess the effect of anaesthetic use on outcomes following incision and drainage (I&D) of simple subcutaneous abscesses.

METHODS

Two cohorts of patients undergoing abscess incision and drainage at St. James' University Hospital in Leeds were identified retrospectively over a 14-week period before (P1) and after (P2) the introduction of the COVID-19 anaesthetic guidelines. The number of follow-up appointments for repacking and representation to healthcare services 30 days after I&D were used as surrogate endpoints for wound healing.

RESULTS

A total of 133 patients were included (n=70, P1 and n=63, P2). Significantly more procedures were performed under LA after the intervention (84.1% vs 5.7%; p<0.0001) with a significant reduction in wound packing (68.3% vs 87.1%; p=0.00473). Follow-up analysis found no significant difference in the median number of follow-up appointments (7.46 vs 5.11; p=0.0731) and the number of patients who required ongoing treatment after 30 days (n=14, P1 vs n=14, P2; p=0.921).

CONCLUSIONS

Drainage of simple subcutaneous abscess under 5cm in diameter is safe under LA, with no significant difference in surrogate endpoints of wound healing observed in this patient cohort. Recurrent packing may not be required. Future work should explore patient-reported outcomes, including pain management, cosmesis and the cost and sustainability implications of a change in this common procedure.

163 A 12-Month Analysis of the Management of Patients with Potential Cauda Equina Syndrome (CES) via Virtual Consultations During the COVID-19 Pandemic

Aim

Approximately 2.6 million people see their GP for lower back pain (LBP) each year. Referrals for spinal surgery are increasing with varying effectiveness. Screening for neurosurgical red flags is critical to quickly identify the rare but serious causes of LBP, such as CES. The primary aim was to explore what effect COVID-19 had on the management pathway of these patients in primary care to investigate causes of LBP including ruling out CES.

Method

A service evaluation of all patients presenting to a large primary care provider in West Yorkshire with lower back pain who underwent MRI lumbar/sacral spine investigation between March 2020 and March 2021 was conducted.

Results

A total of 105 patients with matched MRI scans were included. Neurosurgical red flag screening was performed by virtual appointment only in 32 (30.5%) of patients. In 10 cases (9.5%), red flag screening was not documented. Radiological outcomes revealed three (2.9%) cases of CES. Thirty (28.6%) required onward referral to neurosurgery. The majority (n=56; 53%) had demonstrated radiological pathology amenable to conservative management.

Conclusions

During the pandemic, almost a third of patients in primary care did not receive a face-to-face examination to rule out red flags in lieu of virtual appointments and history alone. The majority of imaging revealed pathology that was amenable to conservative management. The safety of virtual consultations including telephone appointments to screen for neurosurgical pathology needs further investigation. If deemed safe, virtual patient pathways may be optimised to achieve effective recognition patients at risk of CES requiring neurosurgical intervention.

389 Impact of Surgical Drain Output Monitoring on Patient Outcomes in Gastrointestinal Surgery: A Systematic Review

Aim

Surgical drains are widely utilised in Gastrointestinal Surgery to prevent intra-abdominal collections and identify post-operative complications. Surgical drain monitoring ranges from simple output measurements through to specific analysis for constituents such as amylase. This systematic review aimed to determine whether surgical drain monitoring can detect post-operative complications and impact on patient outcomes.

Method

A systematic review was performed, and the following databases searched between 02/03/20 and 26/04/20: MEDLINE, EMBASE, The Cochrane Library and Clinicaltrials.gov. All studies describing surgical drain monitoring of output and content in adult patients undergoing gastrointestinal surgery were considered. Other invasive methods of intra-abdominal sampling were excluded.

Results

The search returned 396 articles. Following abstract review, 383 were excluded and 13 articles were included for full review. The studies were classified according to speciality: Oesophagogastric (1), Pancreatic (6), Hepatobiliary (2), Colorectal (3) and Emergency General Surgery (1). Post-operative monitoring of amylase and bilirubin decreased the incidence of post-operative complications (pancreatic fistulas, intra-abdominal infections, surgical site infections), length of stay and mortality rate in Pancreatic and Hepatobiliary Surgery. Testing of drain contents following Colorectal Surgery can aid anastomotic leak and the detection of peritonitis, however this did not confer any improvement in patient outcome. Surgical drain monitoring did not improve patient outcomes in Oesophagogastric Surgery.

Conclusions

Surgical drain monitoring has established advantages in the post-operative care for patients undergoing Gastrointestinal Surgery. Enhanced surgical drain monitoring involving the testing of drain amylase, bilirubin, lactate, and cytokines may improve detection of complications in the immediate post-operative period.

Clinical effectiveness of gasless laparoscopic surgery for abdominal conditions: systematic review and meta-analysis

BACKGROUND

In high-income countries, laparoscopic surgery is the preferred approach for many abdominal conditions. Conventional laparoscopy is a complex intervention that is challenging to adopt and implement in low resource settings. This systematic review and meta-analysis evaluate the clinical effectiveness of gasless laparoscopy compared to conventional laparoscopy with CO₂ pneumoperitoneum and open surgery for general surgery and gynaecological procedures.

METHODS

A search of the MEDLINE, EMBASE, Global Health, AJOL databases and Cochrane Library was performed from inception to January 2021. All randomised (RCTs) and comparative cohort (non-RCTs) studies comparing gasless laparoscopy with open surgery or conventional laparoscopy were included. The primary outcomes were mortality, conversion rates and intraoperative complications.

SECONDARY OUTCOMES

operative times and length of stay. The inverse variance random-effects model was used to synthesise data.

RESULTS

63 studies were included: 41 RCTs and 22 non-RCTs (3,620 patients). No procedure-related deaths were reported in the studies. For gasless vs conventional laparoscopy there was no difference in intraoperative complications for general RR 1.04 [CI 0.45-2.40] or gynaecological surgery RR 0.66 [0.14-3.13]. In the gasless laparoscopy group, the conversion rates for gynaecological surgery were high RR 11.72 [CI 2.26-60.87] when compared to conventional laparoscopy. For gasless vs open surgery, the operative times were longer for gasless surgery in general surgery RCT group MD (mean difference) 10 [CI 0.64, 19.36], but significantly shorter in the gynaecology RCT group MD - 18.74 [CI - 29.23, - 8.26]. For gasless laparoscopy vs open surgery non-RCT, the length of stay was shorter for gasless laparoscopy in general surgery MD - 3.94 [CI - 5.93, - 1.95] and gynaecology MD - 1.75 [CI - 2.64, - 0.86]. Overall GRADE assessment for RCTs and Non-RCTs was very low.

CONCLUSION

Gasless laparoscopy has advantages for selective general and gynaecological procedures and may have a vital role to play in low resource settings.

524 Anaesthetic Use and Packing in Subcutaneous Abscess Management: A Retrospective Before and After Analysis Within A Two-Cycle Audit

Introduction

In the United Kingdom, there are no widely used guidelines within the management of subcutaneous abscesses by incision and drainage (I&D) to direct the use of local anaesthesia (LA) vs genal anaesthesia (GA); or the use of wound packing vs no packing.

Method

Two cohorts of patients undergoing I&D procedures were retrospectively identified from attendance records over a 3.5-month period. The first cohort was between 16th October 2018 to 31st January 2019. The second cohort of patients was during the COVID-19 pandemic following the introduction of new RCS guidance (intervention) between 29th March 2020 and 15th June 2020.

Results

Seventy-one patients before and 63 after the intervention were included. There were significantly more procedures performed under LA after the introduction of the intervention (n = 52; 82.5%) vs before (n = 4; 5.6%) p < 0.0001. The incidence of wound packing decreased after the intervention (n = 43; 68.3% vs n = 62; 87.3%) p = 0.00452.

Conclusions

The results demonstrate that during the pandemic, change in practice resulted in more subcutaneous abscesses being treated with LA. The majority of abscesses were packed in both cohorts although the incidence declined after the intervention. Future research should explore the patient satisfaction regarding pain management and the abscess recurrence rate.

P15: EVALUATING THE INTERNATIONAL USABILITY OF A LOW-COST LAPAROSCOPIC TRAINER IN LOW- AND HIGH-INCOME SETTINGS

Introduction

Limited access to equipment and trained personnel restrict the adoption of laparoscopic surgery globally. There are a wide range of laparoscopic trainers available; however, most of these are not affordable. We propose an ultra-low-cost laparoscopic trainer (Lap-Pack), designed for portability, ease of assembly and compatibility with smart devices. The study aims to evaluate the usability of Lap-Pack as a training tool in low- and high-income settings.

Method

An international usability study was conducted in India and the UK in 2019. The participants (n=60), consisting of senior surgeons (n=18), junior trainees (n=20) and medical students (n=22), were asked to complete two tasks using Lap-Pack. Participants then scored Lap-Pack in a 25-point questionnaire, including a pre-established Face-Validity Criteria and four major evaluation categories – Usability, Camera, View, Material.

Result

Lap-Pack scored highly in Face-Validity with a combined mean score of 4.63 (95%CI: 4.31, 4.95, p &lt;0.05) of a possible 6. In both cohorts, the Usability and Camera categories scored highest, with combined values respectively of 6.10 (95%CI: 6.01, 6.19, p &lt;0.05) and 6.09 (95%CI: 5.88, 6.31, p &lt;0.05) of a possible 7. For both centres, the highest-scoring individual criteria were its light weight and portability.

Conclusion

Overall, Lap-Pack was received positively by medical students and consultants alike, suggesting it is a suitable device for development of skills as part of a larger laparoscopic training curriculum. Its ease of assembly, portability and versatility show promise of increasing access to training opportunities worldwide.

Take-home message

Lap-Pack is an ultra-low-cost, portable laparoscopic simulator featuring compatibility with smart devices designed to help increase access to laparoscopic training worldwide. An international usability study found medical students, junior trainees and senior surgeons rated its usability and camera features highly, suggesting its employability as a laparoscopic training tool on a global scale.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Critical care usage after major gastrointestinal and liver surgery: a prospective, multicentre observational study

BACKGROUND

Patient selection for critical care admission must balance patient safety with optimal resource allocation. This study aimed to determine the relationship between critical care admission, and postoperative mortality after abdominal surgery.

METHODS

This prespecified secondary analysis of a multicentre, prospective, observational study included consecutive patients enrolled in the DISCOVER study from UK and Republic of Ireland undergoing major gastrointestinal and liver surgery between October and December 2014. The primary outcome was 30-day mortality. Multivariate logistic regression was used to explore associations between critical care admission (planned and unplanned) and mortality, and inter-centre variation in critical care admission after emergency laparotomy.

RESULTS

Of 4529 patients included, 37.8% (n=1713) underwent planned critical care admissions from theatre. Some 3.1% (n=86/2816) admitted to ward-level care subsequently underwent unplanned critical care admission. Overall 30-day mortality was 2.9% (n=133/4519), and the risk-adjusted association between 30-day mortality and critical care admission was higher in unplanned [odds ratio (OR): 8.65, 95% confidence interval (CI): 3.51-19.97) than planned admissions (OR: 2.32, 95% CI: 1.43-3.85). Some 26.7% of patients (n=1210/4529) underwent emergency laparotomies. After adjustment, 49.3% (95% CI: 46.8-51.9%, P<0.001) were predicted to have planned critical care admissions, with 7% (n=10/145) of centres outside the 95% CI.

CONCLUSIONS

After risk adjustment, no 30-day survival benefit was identified for either planned or unplanned postoperative admissions to critical care within this cohort. This likely represents appropriate admission of the highest-risk patients. Planned admissions in selected, intermediate-risk patients may present a strategy to mitigate the risk of unplanned admission. Substantial inter-centre variation exists in planned critical care admissions after emergency laparotomies.

Follow-up of six blood donors highlights the complementary role and limitations of hepatitis C virus antibody and nucleic acid amplification tests

BACKGROUND AND OBJECTIVES

The purpose of this study was to analyse the follow-up results for six blood donors who screened positive for hepatitis C virus (HCV) by nucleic acid amplification technology (NAT) but were non-reactive in the primary antibody immunoassay (HCV NAT yield).

MATERIALS AND METHODS

Volunteer blood donations were screened, in parallel, for antibodies to hepatitis C virus (anti-HCV) and for human immunodeficiency virus (HIV)/HCV RNA using the Abbott PRISM HCV Chemiluminescent immunoassay (ChLIA) and the Chiron Procleix HIV-1/HCV RNA assays, respectively. NAT yield donor samples were further tested using supplemental assays, including an alternate HCV antibody enzyme immunoassay (EIA) (Abbott Murex anti-HCV Version 4), an immunoblot (Ortho RIBA-3 or Genelabs Diagnostics HCV Blot 3.0) and two alternative HCV NAT assays [Roche HCV Amplicor and an assembled HCV polymerase chain reaction (PCR)]. Five of the six donors were available for follow-up testing.

RESULTS

The six NAT yield donations were identified as constituents of 24-member minipools among 2,212,695 donations screened over the 28-month study period. All samples were positive when tested, undiluted, using the Roche Amplicor and assembled reverse transcription-polymerase chain reaction (RT-PCR) alternate NAT assays. One of the donors, subsequent to seroconversion, showed RNA levels that fluctuated above and below the limit of detection of the NAT screening assay. Three of the six were reactive on the secondary EIA and showed reactivity to the core c22(p) antigen by immunoblot at the index donation. Two others subsequently became reactive in the ChLIA prior to the EIA, showing reactivity against c100 and/or c33c antigens by immunoblot. The remaining donor became reactive in the ChLIA and EIA at the same time, showing RIBA reactivity against all of the following three peptides: c100; c33c; and c22(p).

CONCLUSIONS

This study demonstrated that at least five of six HCV NAT yield donors were in the pre- or early antibody seroconversion phase of infection. The observation that one yield donor demonstrated HCV RNA that fluctuated above and below the limit of detection of the primary NAT-screening assay supports the maintenance of both NAT and antibody screening for HCV. Follow-up testing of suspected yield donors revealed that the primary and alternate anti-HCV immunoassays had different performance characteristics, depending on the specificity of the donor's early anti-HCV response.

Identification of a new recipient in the Sydney Blood Bank Cohort: a long-term HIV type 1-infected seroindeterminate individual

We have reported previously a cohort of long-term survivors of HIV-1 infection, known as the Sydney Blood Bank Cohort, who received HIV-1-positive blood from a common infected donor. A new recipient, C135, has been identified. This recipient became infected after receiving blood donated during the presumed time of seroconversion of the donor in February 1981. C135 has been infected for more than 18 years without signs of disease progression. The virus load in this recipient has remained below the detectable level (<20 RNA copies/ml of plasma) and repeated Western blot analyses have given an indeterminate result. By booster PCR techniques we have demonstrated that this individual is infected with HIV-1 and have characterized the viral nef and nef/LTR region sequences present. The strain of HIV-1 identified contains deletions of 88 bp from the nef alone region and a total of 139 bp deleted from the nef/LTR overlap and LTR regions. The LTR contains three wild-type Sp1 transcription factor-binding sites, the 3' wildtype NF-kappaB site, and a duplicated Sp1 and NF-kappaB region. A truncated Nef protein of only 19 amino acids is encoded. The deletions and rearrangements in the nef gene and LTR sequences are characteristic of Sydney Blood Bank Cohort strains of virus. The identification of C135 increases the Sydney Blood Bank Cohort size to nine individuals and represents a rare example of a genuine, long-term HIV-1 infection accompanied by indeterminate anti-HIV-1 serology.

Cutting edge: MHC class I triggering by a novel cell surface ligand costimulates proliferation of activated human T cells

BY55 is a human cell surface molecule whose expression is restricted to NK cells, a subset of circulating CD8+ T lymphocytes, and all intestinal intraepithelial T lymphocytes. Here, we report that BY55 is a novel NK receptor showing broad specificity for both classical and nonclassical MHC class I molecules, and that optimal binding requires a prior aggregation of MHC class I complexes. Using BY55 transfectants, we have identified functional consequences of MHC class I/ligand interactions for the class I-bearing cell. The triggering of MHC class I molecules on human T cell clones by BY55 delivered a potent proliferative signal in the presence of soluble CD3 mAb. The costimulatory signal provided by MHC class I ligation was only seen in activated, and not resting, peripheral blood T cells. This observation represents an additional and/or alternative pathway to CD28 costimulation and may be of particular relevance in memory T cells lacking CD28, such as intestinal intraepithelial T lymphocytes, which are CD28- but BY55+.

Unique HIV type 1 V3 region sequences derived from six different regions of brain: region-specific evolution within host-determined quasispecies

HIV type 1 viral quasispecies were amplified by polymerase chain reaction (PCR) in the hypervariable V3 region of gp120 from six different regions of the brain (right and left frontal; right and left parietal; and right and left occipital) and from the peripheral blood mononuclear cells (PBMCs) of a patient who died of AIDS dementia complex (ADC). Cloning and sequencing of the entire V3 region suggested the presence of genetically unique sequences in different regions of the brain. In contrast, the blood-derived viral quasispecies carried homogeneous sequences that were characterized by a single octapeptide crest motif (HLGPGSAF), a motif important in viral fusion. The brain-derived viral strains showed extensive sequence heterogeneity and the presence of seven different octapeptide and four different tetrapeptide crest motifs (HIGPGRAF, RIGPGRAF, HIGPGSAI, HLGPGSAF, HIGPESAI, HLGPESAI, and YLRPGSAF). In addition, the brain-derived strains were also characterized by variable net V3 loop charge and hydrophilicity, along with distinct amino acid changes specific to different brain regions. Together, the sequence and phylogenetic analyses are unique in identifying the complexity of a viral quasispecies and its independent regional evolution within the brain compartment. Uniquely divergent viral strains were identified in the frontal regions and their presence was further supported by the presence of multinucleated giant cells (characteristic of HIV encephalopathy) predominantly in the left and right frontal regions. In summary, these analyses suggest that genetically different populations of HIV-1 may be present in different brain compartments and confirm that specific neurotropic variants may exist.

Molecular analyses of human immunodeficiency virus type 1 V3 region quasispecies derived from plasma and peripheral blood mononuclear cells of the first long-term-nonprogressing mother and child pair

Molecular analyses were done for the V3 region quasispecies of human immunodeficiency virus type 1 (HIV-1) strains from plasma and peripheral blood mononuclear cells of the first HIV-1-infected long-term-nonprogressing mother-child pair whose members have survived for >13 years with stable CD4 T cell counts. There was a predominance of lower V3 loop charge and the absence of genotypic changes that are critical in phenotypic determination and tropism during HIV-1 infection. The intrahost genetic diversity between HIV-1 strains from the mother-child pair compared with HIV-1 strains from slow and rapid progressors suggested that a high genetic heterogeneity in HIV-1 strains from this HIV-1-infected long-term-nonprogressing mother and child pair was directly proportional to the length of their immunocompetent period.

Simian T cell leukemia virus type I from naturally infected feral monkeys from central and west Africa encodes a 91-amino acid p12 (ORF-I) protein as opposed to a 99-amino acid protein encoded by HTLV type I from humans

A single protein of 12 kDa, p12 is encoded by the HTLV-I genome from both the singly spliced mRNA pX-ORF-I and doubly spliced mRNA pX-rex-ORF-I. While many full-length sequences of HTLV-1 are known, data on the p12 regions of African STLV-I are unavailable. We have undertaken to sequence the p12 gene in STLV-I from Central and West Africa naturally infected primates, and have compared them to known p12 sequences of HTLV-I. Our data on sequence and in vitro transcription-translation analyses indicate that p12 is a 91-amino acid (aa) protein among STLV-I strains from Central and West Africa, in contrast to the 99-aa protein found among HTLV-I strains around the globe. The p12 sequences of STLV-I exhibit a marked genetic variability at the level of both nucleotide and peptide sequences. Hydropathic and helical wheel analyses reveal that 60% of residues in HTLV-I p12 are hydrophobic, in contrast to 55% in STLV-I from Africa. Although HTLV-I and STLV-I show a similar putative antigenic site, a second potential site was located exclusively in STLV-I from Africa. There are differences in the predicted transmembrane domains in p12 between STLV-I and HTLV-I. Furthermore, the secondary structure data according to the Chou and Fasman algorithm predict an alpha-helical domain at the carboxy terminus in HTLV-I, and this domain may be truncated in STLV-I p12. The amino acid sequence of p12 shows two leucine zipper motifs (LZMs) at the amino terminus and in the middle region, respectively. This is the first report describing the size differences in p12 protein between HTLV-I and STLV-I, which may provide insights into pathogenic mechanisms used by HTLV-I and STLV-I.

Cell cycle regulated expression of nucleolar antigen P120 in normal and transformed human fibroblasts

Normal and SV40 virus-transformed WI-38 human lung fibroblasts were serum starved and refed, or synchronized by double thymidine block and released from the block. At different time points in the cell cycle, steady state levels of P120 mRNA and P120 protein content of the cells were determined by densitometric scans of Northern and Western blots. At the same time points, [3H]thymidine uptake was measured and flow cytometric analysis performed for DNA content and P120 antigen staining. Levels of P120 protein and P120 mRNA were approximately 4 times greater in non-synchronous, exponentially growing transformed cells than in similarly growing normal cells. Early G1-phase cells, synchronized either with serum deprivation or with metabolic block, contained only a trace amount of P120 protein and mRNA. The P120 gene was transcribed early in G1 and P120 protein synthesis initiated in middle G1. A dramatic increase of P120 protein level occurred in S-phase with a corresponding mRNA peak preceding the P120 protein peak. These results indicate that P120 is overexpressed in transformed WI-38 cells and that P120 is temporally regulated during the cell cycle of both transformed and normal fibroblasts. The dramatic increase in P120 protein expression at the G1 to S boundary suggests that P120 may play a role in the regulation of cell cycle and increased nucleolar activity that is associated with cell proliferation.

A longitudinal study of social support and depression in unemployed men

Interviews were conducted with 49 men just after they had become unemployed, and with a matched sample of 49 employed men. Follow-up interviews took place 6-8 months later. At follow-up 20 originally unemployed men were still without work, and were significantly more depressed than the employed. Five of these 20, but no employed men, had become clinically depressed. In a multiple regression analysis there was a significant employment X social support interaction which indicated that depression scores at follow-up were higher in those who remained unemployed and who had little social contact with others in the month before losing their jobs. Depression becomes likely when people lose a source of social interaction that is important to their sense of worth, and have no alternative means of experiencing this worth in other relationships.

Mechanical and biological properties of the GORE-TEX expanded polytetrafluoroethylene (PTFE) prosthetic ligament

Data from these studies have resulted in a modified implant technique which has taken into consideration the salient points from this and previous studies. Ongoing animal studies will provide a better understanding of the long-term performance of the material in the anterior cruciate ligament and medial collateral ligament positions. Additional studies will be implemented as new techniques and applications evolve. The key conclusions of this study are as follows: 1. This prosthetic ligament system is not intended to match the mechanical properties of the normal anterior cruciate ligament in dogs. However, in the dog at one to four months the GORE-TEX Prosthetic Ligament system is at least comparable in tensile strength to the repaired anterior cruciate ligament utilizing autogenous tissue at eight months. 2. One square knot with wire augmentation, appears to be an adequate method of fixation; however, since proximal placement of the knot will result in a mild bursitis formation, the implant technique has been modified so that the knot is placed more distally under the cranial tibial muscle. 3. The porosity of the material is adequate to allow for the tissue ingrowth, which is essential for fixation augmentation. 4. The recommended method of implantation appears to be crucial to satisfactory long-term performance of the device. Of particular importance, all edges of drill holes must be thoroughly radiused in order to minimize stress concentrations. 5. The GORE-TEX Prosthetic Ligament implanted in the anterior cruciate ligament position was effective in maintaining joint stability in the dog for up to four months. Ongoing studies have demonstrated maintenance of joint stability for up to ten months. 6. The limb need not be immobilized in order to assure healing and adequate fixation of the device. The immediate relative stability produced by the GORE-TEX Prosthetic Ligament system is adequate to encourage early mobilization. The only protection required is to allow soft tissue healing and initial tissue attachment to the graft material.