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PubMed2025

Beacon Reconstruction Attack: Reconstruction of genomes in genomic data-sharing beacons using summary statistics.

MOTIVATION: Genomic data-sharing beacon protocol, developed by the Global Alliance for Genomics and Health, offers a privacy-preserving mechanism for querying genomic datasets while restricting direct data access. Despite their design, beacons remain vulnerable to privacy attacks. This study introduces a novel privacy vulnerability of the protocol: one can reconstruct large portions of the genomes of all beacon participants by only using the summary statistics reported by the protocol. RESULTS: We introduce a novel optimization-based algorithm that leverages beacon responses and SNP correlations for reconstruction. By optimizing for the SNP correlations and allele frequencies, the proposed approach achieves genome reconstruction with a substantially higher F1-score (70%) compared to baseline methods (45%) on beacons generated using individuals from the HapMap and OpenSNP datasets. We show that reconstructed genomes can be used by downstream applications such as in membership inference attacks against other beacons. Our findings reveal that beacons releasing allele frequencies substantially increase the reconstruction risk, underscoring the need for enhanced privacy-preserving mechanisms to protect genomic data. AVAILABILITY AND IMPLEMENTATION: Our implementation is available at https://github.com/ASAP-Bilkent/Beacon-Reconstruction-Attack.

Genomics↗
PubMed2002

Scalping forehead flap for extranasal reconstructions: total reconstruction of the lower lid.

J. M. Converse described the scalping forehead flap in 1942 with the aim of using it in total nasal reconstruction. A rich net of arterial and venous vessels constitute the basic pattern of its blood supply through three principal pedicles: (1) temporal superficial, (2) supraorbital, and (3) supratrochlear. It was described for nasal reconstruction, but due to its characteristics, such as color of the frontal skin, texture, hairless skin, and reliable irrigation, it can be used in the reconstruction of other facial areas. According to these particularities, the Converse flap was used in the reconstruction of a total left lower lid and adjacent lateral nose and cheek areas in a patient with an extended squamous carcinoma. The tumoral resection included the removal of (1) complete lower lid, (2) lacrimal lower canaliculus, sac, and nasolacrimal duct, (3) lower ocular conjunctiva, (4) intraorbitary fat and both inferior oblique and inferior rectus muscles, and (5) adjacent skin of the nose and cheek. Postoperative controls showed an excellent aesthetic and functional result. A hypochromic frontal skin graft was the only sequela; definitive skin coloration was obtained by a dermopigmentation technique. The versatility of this forehead flap allows it to be successfully used for reconstruction not only in the nasal area but also in other facial ones.

Aged↗
PubMed1998

Immediate breast reconstruction in two stages using textured, integrated-valve tissue expanders and breast implants: a retrospective review of 171 consecutive breast reconstructions from 1989 to 1996.

A 7-year experience with 171 consecutive immediate breast reconstructions by one surgeon using a textured integrated-valve tissue expander was reviewed. All patients were reconstructed in multiple stages using a temporary biodimensional tissue expander followed months later by a long term implant. There was one (0.6 percent) spontaneous expander deflation that was replaced. Two (1.2 percent) expanders were removed for infection, and one was removed electively. Fourteen patients (8 percent) had flaps as well as expanders. Initially, expanders were replaced with silicone gel-filled and round saline-filled implants. Later, expanders were replaced mostly with anatomically designed textured saline-filled implants. Of the 171 expanders, 139 were thus ultimately followed by such anatomic designs. Seven (4 percent) of the implants were replaced because of deflation over 7 years. Five patients were lost to follow-up during the expansion phase of their reconstruction. Thirteen percent of these reconstructions received local radiation either before, during, or after expansion. There were a total of five (2.9 percent) significant capsular contractures, with four of them occurring in radiated patients. Ninety-eight percent of a subgroup of 42 consecutively queried patients expressed satisfaction with their reconstruction, while only 2 percent of the queried patients were dissatisfied.

Breast Implants↗
PubMed1999

Anatomic reconstruction of the nasal tip cartilages in secondary and reconstructive rhinoplasty.

Most techniques for secondary rhinoplasty assume that useful residual remnants of the tip cartilages remain, but frequently the alar cartilages are missing--unilaterally, bilaterally, completely, or incompletely--with loss of the lateral crura, middle crura, and parts of the medial crura. In such severe cases, excision of scar tissue and the residual alar remnants and their replacement with nonanatomic tip grafts have been recommended. Multiple solid, bruised, or crushed cartilage fragments are positioned in a closed pocket or solid shield-shaped grafts are fixed with sutures during an open rhinoplasty. These onlay filler grafts only increase tip projection and definition. Associated tip abnormalities (alar rim notching, columellar retraction, nostril distortion) are not addressed. Problems with graft visibility, an unnatural appearance, or malposition have been noted. Fortunately, techniques useful in reconstructive rhinoplasty can be applied to severe cosmetic secondary deformities. Anatomic cartilage replacements similar in shape, bulk, and position to normal alar cartilages can be fashioned from septal, ear, and rib cartilage, fixed to the residual medial crura and/or a columellar strut, and bent backward to restore the normal skeletal framework of the tip. During an open rhinoplasty, a fabricated and rigid framework is designed to replace the missing medial, middle, or lateral crus of one or both alar cartilages. The entire alar tripod is recreated. These anatomic alar cartilage reconstructive grafts create tip definition and projection, fill the lobule and restore the expected lateral convexity, position the columella and establish columellar length, secure and position the alar rim, and brace the external valve against collapse, support the vestibular lining, and restore a nostril shape. The anatomic form and function of the nasal tip is restored. This technique is recommended when alar cartilages are significantly destroyed or absent in secondary or reconstructive rhinoplasty and the alar remnants are insufficient for repair. Anatomically designed alar cartilage replacements allow an aesthetically structured skeleton to contour the overlying skin envelope. Problems with displacement are minimized by graft fixation. Graft visibility is used to the surgeon's advantage. A rigidly supported framework with a nasal shape can mold a covering forehead flap or the scarred tip skin of a secondary rhinoplasty and create a result that may approach normal. Anatomic alar cartilage reconstructions were used in eight reconstructive and eight secondary rhinoplasties in the last 5 years. Their use in the repair of postrhinoplasty deformities is emphasized.

Cartilage↗
PubMed1998

Application of reconstruction-based scatter compensation to thallium-201 SPECT: implementations for reduced reconstructed image noise.

Scatter compensation in Tl-201 single photon emission computed tomography (SPECT) presents an interesting challenge because of the multiple emission energies and relatively large proportion of scattered photons. In this paper, we present a simulation study investigating reconstructed image noise levels arising from various implementations of iterative reconstruction-based scatter compensation (RBSC) in Tl-201 SPECT. A two-stage analysis was used to study single and multiple energy window implementations of reconstruction-based scatter compensation, and RBSC was compared to the upper limits on performance for other approaches to handling scatter. In the first stage, singular value decomposition of the system transfer matrix was used to analyze noise levels in a manner independent of the choice of reconstruction algorithm, providing results valid across a wide range of regularizations. In the second stage, the data were reconstructed using maximum-likelihood expectation-maximization, and the noise properties of the resultant images were analyzed. The best RBSC performance was obtained using multiple energy windows, one for each emission photopeak, and RBSC outperformed the upper limit on subtraction-based compensation methods. Implementing RBSC with the correct choice of energy window acquisition scheme is a promising method for performing scatter compensation for Tl-201 SPECT.

Phantoms, Imaging↗
PubMed2004

Eyebrow reconstruction: options for reconstruction of cutaneous defects of the eyebrow.

BACKGROUND: Reconstruction of cutaneous eyebrow defects is a challenge, as eyebrow positioning provides an important role in communication, cosmesis, and signaling age, gender, and emotional status. Special consideration must be paid in order to maintain eyebrow symmetry and to avoid distortion of the hairline. OBJECTIVE: To demonstrate reconstructive options for the eyebrow that preserve maximal function and cosmesis. METHODS: The anatomy and function of the eyebrow are reviewed. Descriptions of five techniques of eyebrow reconstruction are then presented, including specific limitations and benefits of each closure option. Pertinent details regarding flap mechanics, design, and patient selection are also included. RESULTS: There are several options available for reconstruction of the eyebrow. Each closure method has advantages and disadvantages. The selection must be individualized, depending on the extent and location of the eyebrow defect relationship to other structures, gender, and age of patients. Each of the five closure options aid to maintain the function and aesthetic appearance of the eyebrow. CONCLUSION: Understanding the unique anatomy and function of the eyebrow, including its movement in facial expression, is useful in achieving good reconstructive outcomes while maintaining normal eyebrow function.

Eyebrows↗
PubMed1986

Primary mandibular reconstruction using the AO reconstruction plate.

Primary reconstruction of segmental defects of the mandible following cancer resection remains a major problem. In 1976, a stainless steel plate was developed by AO/ASIF (Arbeitsgemeinschaft für Osteosynthesefragen/Association for the Study of Internal Fixation) for mandibular reconstruction. This plate completely stabilizes both mandibular stumps without the need for intermaxillary or external fixation. In addition, when bone grafting is performed, the design of this plate promotes revascularization by allowing maximal contact between grafted cancellous bone and surrounding soft tissue. Since April 1985, we have used this reconstruction plate in six patients undergoing composite resection. The technique did not compromise cancer resection, excessively prolong operating time, or alter postoperative management. All six patients have retained the AO reconstruction plate and have been reconstructed successfully with achievement of satisfactory function and cosmesis.

Adult↗
PubMed1991

Functional evaluation following microvascular oromandibular reconstruction of the oral cancer patient: a comparative study of reconstructed and nonreconstructed patients.

Over the past decade, the use of free flap transfers in head and neck surgery has led to remarkable advances in the reliability and the ultimate results of oromandibular reconstruction. Stable and retentive dental restorations have been achieved using enosseous implants placed directly into the vascularized bone flaps. However, the functional assessment of patients who underwent primary mandibular reconstruction with these techniques has not been previously reported. A group of 10 reconstructed and 10 nonreconstructed segmental hemimandibulectomy patients were compared using a battery of tests to assess their overall well-being, cosmesis, deglutition, oral competence, speech, length of hospitalization, and dental rehabilitation. In addition, objective measures of the masticatory apparatus (interincisal opening, bite force, chewing performance, and chewing stroke) were used to compare these two groups as well as normal healthy subjects and edentulous patients restored with conventional and implant-borne dentures. The results show a clear advantage for the reconstructed patients in almost all categories. Persistent problems and future directions in oromandibular reconstruction are discussed.

Adult↗
PubMed1997

Limits for the use of forehead flaps for small and extensive midface reconstructions including septum/columella reconstructions.

I describe six selected cases of challenging reconstructions in the midface including a small deepithelialised and tunnelled flap for volume-replacement and conjunctiva-reconstruction in the orbit and a case of septum/columella reconstruction with a tunnelled paramedian forehead flap. Big flaps for extensive complex reconstructions in the midface (cheek, lip, and nose) emphasis the efficiency of the flaps. In extensive reconstructions the paramedian forehead might primarily be used for lining. Indian forehead flaps should be dissected to the base in the upper eyelid to increase their strength and for greater versatility. The base can be de-epithelialised without threatening its viability. This procedure allows the flap to be tunnelled and increases the mobility of the flap. Long flaps can even be folded without delay.

Aged↗
PubMed1998

[The results after 10-16 years of the treatment of chronic anterior laxity of the knee using reconstruction of the anterior cruciate ligament with a patellar tendon graft combined with an external extra-articular reconstruction].

PURPOSE OF THE STUDY: The aim of this prospective study was to evaluate the objective postoperative laxity and functional results with a minimum follow-up of 10 years (mean 11.7 +/- 2 years) in chronic anterior knee instability treated by ACL reconstruction associated to a lateral extra-articular plasty. MATERIAL AND METHODS: 138 patients of a mean age of 27.8 +/- 8.5 years had been operated. Delay between injury and operation was 4 +/- 4.8 years. The surgical "Mac Injones" procedure used a free autologous patellar tendon graft with a bone-to-bone fixation, supplemented by a lateral extra-articular plasty using a strip of quadriceps tendon as a direct prolongation of the graft of the patellar tendon and patella itself. A rehabilitation program aimed to an early recovery of a complete range of motion. Anterior laxity had been measured before and after operation using two instrumented methods, KT-1000 and stress-radiography (at 20 degrees of flexion with a 9 kg load applied at the distal part of the thigh) with measurements of the displacement in medial and lateral compartments. Tunnel positioning was appreciated radiologically. Function was evaluated using the International Knee Documentation Committee score (I.K.D.C.). RESULTS: Elongation of the reconstructed ligament occurred mainly during the first 6 month, but was independent from early full range of motion recovery. Laxity was stabilized after one year. The final laxity gain of the medial compartment was 62 per cent and for the lateral compartment 77 per cent. The pivot shift test was negative in 66 per cent, grade 2 in 4 per cent, grade 1 in 30 per cent. Functional results were excellent and good (A and B) in 60.4 per cent and 76.7 per cent returned to sports activity. 12 reconstructed ligaments reruptured. Arthritis was the cause of poor results in other cases (13.8 per cent). DISCUSSION: Lateral extra-articular plasty is unable to better control translation of the medial compartment than isolated anterior cruciate ligament reconstruction, but laxity of the lateral compartment was minimized and the pivot shift test also. Incorrect position of the anterior cruciate ligament was correlated with poor results. CONCLUSION: This documented study on laxity of the two compartments confirms the interest of each type of reconstruction, in particular extra-articular plasty when made with quadriceps tendon and so doing, preserving the iliotibial-band for the control of varus stability.

Adolescent↗
PubMed2005

[Treatment of the contralateral breast in breast reconstruction. Nipple-areola reconstruction].

The final objective of breast reconstruction is to equalize as far as possible the appearance between the reconstructed breast and the contralateral breast. To this end, once the new breast monticle has been obtained through different techniques of breast reconstruction, we employ a different series of surgical techniques that allow us to obtain symmetry. In this way, we act on the one hand on the contralateral breast (either increasing it, reducing it or raising it), and on the other we act on the reconstructed breast, recreating a new nipple-areola complex, which will complete the reconstruction by giving this breast a more real and suitable appearance.

Female↗
PubMedDate not supplied

[Plastic face reconstruction as a possibility for identifying unknown skulls (II). An evaluation of the reliability of the reconstruction technic by a double-blind trial].

In a double blind-trial two examiners reconstructed the soft tissue on lifelike casts of 12 skulls. They worked independently after having been given information about age, sex and constitution of the person in question and following a reconstruction plan based on the morphology of the skull. The comparison of the completed reconstruction with each other chiefly showed approximate to far-reaching degrees of resemblance and conformity. The comparison of reconstructions and photographs of the individuals also showed predominantly approximate to far-reaching likeness of the general impression, and, with one exception, at least little likeness was achieved. The reconstruction of soft tissue on the skull proved to be a relatively useful method of identifying unknown skulls, provided information on the colour and length of the hair, and possibly on the hairstyle as well, is at the examiner's disposal.

Adult↗
PubMed1988

[Clinical and experimental study on reconstruction after pancreatectomy--Part I. Cholangitis and its relationship to reconstruction].

The purpose of the present study is to clarify pathogenesis of cholangitis after pancreatectomy. The clinical study consisted of follow-up survey and hepatobiliary scintigraphy for the patients with type-I reconstruction (e.g. Imanaga procedure) and type-II reconstruction (e.g. Child procedure) after pancreatoduodenectomy. The experimental study was performed in dogs by creating three types of biliary reconstruction, namely, cholecystoduodenostomy (C-D), cholecystojejunostomy (C-J) and Roux-Y cholecystojejunostomy (R-Y). In the follow-up survey, cholangitis occurred in 19.0% of 21 type-I patients and in 33.3% of 18 type-II patients. In the hepatobiliary scintigraphy, type-I demonstrated smooth transit of bile along the reestablishing intestine. Type-II, on the other hand, showed marked stagnation of bile in the excluded loop, which could even trigger cholangitis. The experimental study showed that the results obtained from R-Y were no better than those obtained from C-D and C-J with respect to prevention of cholangitis based on histological, biochemical and bacteriological point of view. These studies suggest that type-I reconstruction carries little risk of causing cholangitis, whereas type-II reconstruction is not effective in preventing cholangitis.

Anastomosis, Roux-en-Y↗
PubMed1986

[A new method for the reconstruction of injured flexor tendons of the hand: tendons and tendon sheath reconstruction in 2 stages].

The authors have developed a new two-stage method of flexor tendon reconstruction for injuries in the critical zone of the hand. In the first phase of the secondary operation, they preserve the intact portions of tendon sheath. They replace the scarred tendon sheath: small retinacular defects with autologous vein grafts, larger pulley defects with fascial grafts. A silicon rubber rod is placed in the reconstructed tendon sheath. In the second stage of the operation, after six weeks generally, an autologous tendon is placed in the reconstructed tendon sheath. The authors present their material and results: In 12 of 18 flexor tendon reconstructions they achieved excellent or good results. Therefore, they propose their method for reconstructing injured flexor tendons with an unfavourable prognosis.

Adult↗
PubMed1993

Reconstruction of composite facial defects: the combined application of multiple reconstructive modalities.

OBJECTIVE: To describe the combined use of craniofacial skeletal reconstruction, tissue expansion and microvascular free tissue transfer in the repair of major composite facial defects. DESIGN: Case series with an integrated team approach. SETTING: Craniofacial unit, university teaching hospital. PATIENTS: Three cases were selected to best illustrate the combined use of the three modalities in reconstruction of acute traumatic, congenital and post-traumatic facial defects. A 15-year-old boy had a shotgun wound to the face; a 23-year-old man had Treacher Collins syndrome; and a 55-year-old woman had a post-traumatic composite defect of the central midface. INTERVENTIONS: Preoperatively, complete neurologic, ophthalmologic and dental examinations, anthropometric analysis, prosthodontic assessment, computed tomography and computer graphics. Operatively, craniofacial exposure followed established surgical principles. Skeletal reconstruction was performed to provide accurate positioning of bony segments and three-dimensional stability. Bone grafting was used when necessary to restore bony continuity and increase stability. Tissue expansion was used to provide more locally available tissue for wound closure and resurfacing composite defects. Microsurgical free tissue transfer was used to provide functional replacement of deficient tissues. RESULTS: The results of the modalities used for reconstruction of these composite facial defects are illustrated for each case described. CONCLUSIONS: The use of multiple modalities, including craniofacial skeletal reconstruction, tissue expansion and free tissue transfer, allow the surgeon to address the specific functional and anatomical requirements associated with composite facial defects that are characterized by a combined deficiency of multiple tissues in the craniofacial region.

Adolescent↗
PubMedDate not supplied

Reconstruction of oncologic torso defects: emphasis on microvascular reconstruction.

A large variety of pedicle flaps centered at the shoulder girdle or pelvic girdle, or derived from the epigastric axis, are generally available to reconstruct defects of the torso. However, microvascular free flap reconstruction may occasionally be required for: 1) locations that are difficult to reach with pedicle flaps (the posterolateral iliac crest region, epigastrium, lower lumbar and sacral, and upper back and lower central); 2) locations in which muscles or their vascular pedicles have been destroyed by surgical ablation or irradiation; 3) a large-volume "dead space" or a large surface area that may be inadequately covered by available regional flaps; and 4) a combination of factors. Whether using a pedicle or free flaps, the reconstructive requirements of torso reconstruction must be met: 1) to restore chest wall or abdominal wall integrity, 2) to fill "dead space," 3) to cover vital exposed structures, 4) to maintain skeletal stability of the thoracic cage and minimize respiratory compromise, and 5) to buttress visceral repairs. Semin. Surg. Oncol. 19:255-263, 2000.

Abdominal Neoplasms↗
PubMed2005

[Fillet flaps as a possibility for defect reconstruction of the hand. Reconstruction without additional donor site morbidity].

Fillet flaps offer an additional reconstruction opportunity for complex hand defects after trauma, burns, tumors or infections. This retrospective study elucidates the concept of fillet flaps and presents the results of an overall of 34 plastic surgical reconstructions of the hands in 31 patients. Pedicled axial pattern flaps were used predominantly, except 2 cross finger flaps. In 10 cases the defects were localized in the dorsal and in 9 cases in the palmar aspect of the hand. 14 finger defects and one of the ulnar hand were covered. Very few complications occured. In only 2 cases partial flap loss was observed. An additional wound infection required revision in one case. Another case was left to secondary healing. Prior to any amputation, possible use of spare parts for defect reconstruction should be considered as a matter of principle. Our data suggest that the concept of fillet flaps is suitable for the reconstruction of complex defects of the hands without additional donor site morbidity.

Adolescent↗