Ambulatory Surgery for Pilonidal Sinus : Tract Excision and Open Treatment Followed by At-Home Irrigation

Pilonidal sinus is a cystic disease that occurs most often in the sacrococcygeal region. Surgical excision and coverage with a skin flap require postoperative bed rest. Most affected patients are young adults who find it difficult to obtain adequate postoperative bed rest owing to their work. The purpose of this study is to review the effectiveness of our ambulatory surgery procedure for pilonidal sinus, which involves tract excision and open treatment followed by at-home irrigation. We reviewed the 9 cases of chronic pilonidal sinus treated at our out-patient clinic by ambulatory surgery consisting of open excision without skin closure. Patients were sent home after careful observation for hemostasis at the surgical site. Postoperative wound treatment and irrigation were performed at home by the patients themselves. The mean immediate postoperative follow-up period was 22.3 days (13 to 31 days), and the mean number of follow-up visits was 3.3. No serious complication and recurrence was noted during the long-term follow-up period of 26.3 months (1 to 60 months). Although the healing time following our ambulatory procedure was not short, no postoperative rest was required, and the recurrence rate was zero. We believe this procedure is useful for selected patients with pilonidal sinus

An Extension of Proof Graphs for Disjunctive Parameterised Boolean Equation Systems

A parameterised Boolean equation system (PBES) is a set of equations that defines sets as the least and/or greatest fixed-points that satisfy the equations. This system is regarded as a declarative program defining functions that take a datum and returns a Boolean value. The membership problem of PBESs is a problem to decide whether a given element is in the defined set or not, which corresponds to an execution of the program. This paper introduces reduced proof graphs, and studies a technique to solve the membership problem of PBESs, which is undecidable in general, by transforming it into a reduced proof graph. A vertex X(v) in a proof graph represents that the data v is in the set X, if the graph satisfies conditions induced from a given PBES. Proof graphs are, however, infinite in general. Thus we introduce vertices each of which stands for a set of vertices of the original ones, which possibly results in a finite graph. For a subclass of disjunctive PBESs, we clarify some conditions which reduced proof graphs should satisfy. We also show some examples having no finite proof graph except for reduced one. We further propose a reduced dependency space, which contains reduced proof graphs as sub-graphs if a proof graph exists. We provide a procedure to construct finite reduced dependency spaces, and show the soundness and completeness of the procedure

Proximal nail fold flap for digital mucous cyst excision

The skin covering a digital mucous cyst is often very thin and is often excised with the cyst. Thus, transfer of a skin flap is needed for the defect. We have developed a proximal nail fold flap technique by which the thin skin covering the cyst can be preserved. We conducted a retrospective study to assess the effectiveness and reliability of this technique for digital mucous cyst excision. The study group comprised 26 patients treated for 28 digital mucous cysts. The flap was elevated on the nail matrix to expose the distal interphalangeal joint capsule. To preserve the skin in cases in which the skin covering the cyst was exceptionally thin, we did not excise the upper part of the cyst wall. Excision of the cyst and stalk was successful in all cases. Additional excision of the joint capsule or osteophyte(s) was achieved in 20 cases and 5 cases, respectively. No flap necrosis, skin defect or nail deformity resulted. Three of the cysts recurred and were treated successfully by reoperation involving the same flap elevation technique. We conclude that the proximal nail fold flap is useful for excision and reliable for wound coverage after digital mucous cyst excision

Solving parameterised boolean equation systems with infinite data through quotienting

Parameterised Boolean Equation Systems (PBESs) can be used to represent many different kinds of decision problems. Most notably, model checking and equivalence problems can be encoded in a PBES. Traditional instantiation techniques cannot deal with PBESs with an infinite data domain. We propose an approach that can solve PBESs with infinite data by computing the bisimulation quotient of the underlying graph structure. Furthermore, we show how this technique can be improved by repeatedly searching for finite proofs. Unlike existing approaches, our technique is not restricted to subfragments of PBESs. Experimental results show that our ideas work well in practice and support a wider range of models and properties than state-of-the-art techniques.</p