Primary closure or rhomboid excision and Limberg flap for the management of primary sacrococcygeal pilonidal disease? A meta-analysis of randomized controlled trials.

AIM: Sacrococcygeal pilonidal disease is a common condition afflicting the young male working and student population, resulting in considerable pain, embarrassment and loss of work days. Controversy surrounds the most appropriate surgical approach to achieve low recurrence rates whilst minimizing morbidity and permitting an early return to work. This study aims to review the published literature comparing excision followed by either primary suture or rhomboid flap repair. METHODS: PubMed, EMBASE, MEDLINE and The Cochrane Library were systematically reviewed, by two independent investigators, for relevant randomized controlled trials. Keywords and MeSH terms included 'pilonidal disease', 'primary suture/repair', 'rhomboid flap' and 'limberg/modified Limberg flap'. 'Related study' function and manuscript bibliographies were searched for further relevant studies. Study quality was assessed using the Jadad score. Meta-analysis was performed on pooled data, utilizing a random effects model when heterogeneity was high and a fixed effects model when heterogeneity was low. The primary end-point assessed was disease recurrence. Secondary end-points included wound dehiscence, pain scores, hospital stay and return to work. RESULTS: Six studies were eventually included for pooled analysis following exclusion of randomized controlled trials with poor methodology. Two studies compared 'off-midline' (Karydakis) primary suture with the Limberg flap repair. Six hundred and forty-one patients were included (331 flap repairs). Rhomboid flap excision demonstrated a trend towards less disease recurrence (P = 0.07), lower wound infection (P = 0.001) and dehiscence (P = 0.01). However, no significant difference was found for pain scores, hospital stay or return to work. CONCLUSION: The current published literature supports the use of the rhomboid flap excision and the Limberg flap-repair procedures over primary midline suture techniques for the elective management of primary pilonidal disease. Further high-quality studies are necessary to compare flap with off-midline repairs.

Hughes Abdominal Repair Trial (HART) - Abdominal wall closure techniques to reduce the incidence of incisional hernias: study protocol for a randomised controlled trial.

BACKGROUND: Incisional hernias are common complications of midline closure following abdominal surgery and cause significant morbidity, impaired quality of life and increased health care costs. The 'Hughes Repair' combines a standard mass closure with a series of horizontal and two vertical mattress sutures within a single suture. This theoretically distributes the load along the incision length as well as across it. There is evidence to suggest that this technique is as effective as mesh repair for the operative management of incisional hernias; however, no trials have compared the Hughes Repair with standard mass closure for the prevention of incisional hernia formation following a midline incision. METHODS/DESIGN: This is a 1:1 randomised controlled trial comparing two suture techniques for the closure of the midline abdominal wound following surgery for colorectal cancer. Full ethical approval has been gained (Wales REC 3, MREC 12/WA/0374). Eight hundred patients will be randomised from approximately 20 general surgical units within the United Kingdom. Patients undergoing open or laparoscopic (more than a 5-cm midline incision) surgery for colorectal cancer, elective or emergency, are eligible. Patients under the age of 18 years, those having mesh inserted or undergoing musculofascial flap closure of the perineal defect in abdominoperineal wound closure, and those unable to give informed consent will be excluded. Patients will be randomised intraoperatively to either the Hughes Repair or standard mass closure. The primary outcome measure is the incidence of incisional hernias at 1 year as assessed by standardised clinical examination. The secondary outcomes include quality of life patient-reported outcome measures, cost-utility analysis, incidence of complete abdominal wound dehiscence and C-POSSUM scores. The incidence of incisional hernia at 1 year, assessed by computerised tomography, will form a tertiary outcome. DISCUSSION: A feasibility phase has been completed. The results of the study will be used to inform current and future practice and potentially reduce the risk of incisional hernia formation following midline incisions. TRIAL REGISTRATION NUMBER: ISRCTN 25616490 . Registered on 1 January 2012.

PCR in situ: a rapid alternative to in situ hybridization for mapping short, low copy number sequences without isotopes.

A new technique for rapid localization of short, low copy number sequences is described, which uses a form of PCR on preparations of fixed metaphase chromosomes on microscope slides, with the temperature cycling controlled by a flatbed thermal cycler. In its present form, the method is capable of detecting very low copy number sequences, and further development is expected to achieve the target of localizing unique sequences. It has advantages over conventional fluorescent in situ hybridization, both in the speed (easily complete within a work-day) and in the potential sensitivity.

The organisation of repetitive DNA sequences on human chromosomes with respect to the kinetochore analysed using a combination of oligonucleotide primers and CREST anticentromere serum.

The spatial relationship between the families of repetitive DNAs present at the centromeres of human chromosomes and the position of the kinetochore was examined by combining immunocytochemistry with the PRINS oligonucleotide primer extension technique. Heterochromatic domains were decondensed with 5'-azacytidine to facilitate this study. Using this approach our results clearly show that the alphoid DNA sequences are closely associated with the kinetochore of human chromosomes. Simple-sequence satellite DNAs occupy separate, non-overlapping domains within the centromere. These two major families are separated by a third, relatively low-copy repetitive DNA family, SAU-3A. Pulse-field gel electrophoresis was employed to analyse the centromeric domain of human chromosome no. 9 in more detail and the results although preliminary support the conclusions drawn from the immunocytochemistry/PRINS approach.

Oligonucleotide-primed in situ DNA synthesis (PRINS): a method for chromosome mapping, banding, and investigation of sequence organization.

Oligonucleotides were annealed to complementary sequences in fixed human metaphase chromosomes and extended with DNA polymerase. The newly synthesized fragments were labeled by incorporating bio-11-dUTP instead of TTP, and the sites of synthesis were detected by immunocytochemistry, using fluorochromes as the reporter molecules. We have obtained clear localization with oligonucleotides from alphoid (centromeric sequences), simple sequence (satellite) DNAs, a variety of Alu-dispersed repeated sequences, and oligonucleotides derived from the Tetrahymena and Trypanosoma telomere-specific sequences. The simple sequence and alphoid oligonucleotides gave results at least comparable to those obtained using the whole molecule as a probe for in situ hybridization, whereas the Alu oligonucleotides produced a diversity of results which depended on the absolute length and location of the oligonucleotide within the Alu sequence. The telomere-specific oligomers also produced a variety of results. The G-rich Trypanosoma oligomer and its complementary C-rich sequence produced strong telomeric signals and some interstitial signals on mouse chromosomes, but only weak telomeric signals on human chromosomes. The G-rich Tetrahymena oligomer produced detectable telomeric signals on human chromosomes. The technique appears to be a valuable extension of present tools for mapping and examining the organization of DNA sequences within chromosomes.

Gene targeting for somatic cell manipulation: rapid analysis of reduced chromosome hybrids by Alu-PCR fingerprinting and chromosome painting.

The techniques of reverse genetics rely heavily on parasexual methods for manipulating the human genome. However, the application of somatic cell genetics is severely limited by the availability of suitable endogenous selectable markers in the genome. We have addressed this problem by targeting a universally selectable marker into a predetermined region of the genome, using a stringent selection for homologous recombination. Correct gene targeting to human chromosome 7q11 was screened for by Southern blotting and confirmed by fluorescent in situ hybridization. Reduced chromosome 7 hybrids were generated by chromosome mediated gene transfer and selection for the neo gene. The resultant transgenomes were characterized by a combination of L1 fingerprinting, locus specific marker analysis, Alu-PCR and chromosome 'painting'. Alu-PCR and L1 'fingerprints' are complementary and mutually consistent. Chromosome 'painting' reflects and extends the results obtained for specific marker co-transfer. Thus Alu-PCR 'fingerprinting' and 'painting' combine to rapidly provide an accurate picture of transgenome content and complexity. Gene targeting, chromosome tagging and subsequent isolation can be applied to any region of the genome for which a molecular probe is available.

Schizophrenia-associated chromosome 11q21 translocation: identification of flanking markers and development of chromosome 11q fragment hybrids as cloning and mapping resources.

Genetic linkage, molecular analysis, and in situ hybridization have identified TYR and D11S388 as markers flanking the chromosome 11 breakpoint in a large pedigree where a balanced translocation, t(1;11)(q43;q21), segregates with schizophrenia and related affective disorders. Somatic cell hybrids, separating the two translocation chromosomes from each other and from the normal homologues, have been produced with the aid of immunomagnetic sorting for chromosome 1- and chromosome 11-encoded cell-surface antigens. The genes for two of these antigens map on either side of the 11q breakpoint. Immunomagnetic bead sorting was also used to isolate two stable X-irradiation hybrids for each cell-surface antigen. Each hybrid carries only chromosome 11 fragments. Translocation and X-irradiation hybrids were analyzed, mainly by PCR, for the presence of 19 chromosome 11 and 4 chromosome 1 markers. Ten newly designed primers are reported. The X-irradiation hybrids were also studied cytogenetically, for human DNA content, by in situ Cot1 DNA hybridization and by painting the Alu-PCR products from these four lines back onto normal human metaphases. The generation of the translocation hybrids and of the chromosome 11q fragment hybrids is a necessary preliminary to determining whether a schizophrenia-predisposition gene SCZD2 is encoded at this site.