IMPLEMENTASI MODEL ACCELERATED FAILURE TIME (AFT) BERDISTRIBUSI LOG-LOGISTIK PADA PASIEN PENYAKIT JANTUNG BAWAAN

Log-Logistic Accelerated Failure Time (AFT) model is survival analysis that is used when the survival time follows Log-Logistic distribution. Log-Logistic AFT model can be used to estimate survival time, survival function, and hazard function. Log-Logistic AFT model was formed by regressing covariates linierly against the log of survival time. Regression coefficients are estimated using maximum likelihood method. This study uses data from Atrial Septal Defect (ASD) patients, which is a congenital disease with a hole in the wall that separates the top of two chambers of the heart by using sensor type III. Survival time as the response variable, that is the time from patient was diagnosed with ASD until the first relapse and uses age, gender, treatment status (catheterization/surgery), defect size that is the size of the hole in the heart terrace, pulmonary hypertension status, and pain status as predictor variables. The result showed that variable gender, treatment status, defect size, pulmonary hypertension status, and pain status affect the first recurrence of ASD patients, so it is found that category of female, untreated patient, defect size ≥12mm, having pulmonary hypertension, having chest pain tend to have first recurrence sooner than the other category.

Microsurgical reconstruction of the skull base and midface after orbitomaxillary resections for malignant tumors

Background. Orbitomaxillary resection includes exenteration of the orbital contents with resection of the inferior orbital and medial walls. The main goals are: reconstruction of soft tissue and bone structure defects, tamponade of the orbital cavity and/or its preparation for further ocular prosthetics, and reconstruction of the skull base defect. The purpose of the study to present the immediate results of orbitomaxillary resections in patients with malignant neoplasms of the skull base and midface. Material and methods. Between 2014 and 2020, 6 patients who previously underwent surgery for primary cancer (n=3) and recurrent cancer (n=3) were treated at the Head and Neck cancer department of N.N. Blokhin National medical Research center of oncology. To reconstruct defects after resection of bone structures (maxilla, frontal and nasal bones) and skin, a musculocutaneous alt-flap was used in 3 (50 %) cases and a fascial skin radial flap in 3 (50 %) cases. Results. The aesthetic result was assessed in 6 patients. In all cases, a satisfactory result was obtained. None of the patients who underwent resection of the dura mater followed by reconstruction had no symptoms of liquorrhea in the postoperative period. Conclusion. Flap selection depends on the defect size. In cases with a small defect size (up to 70 cm3), reconstruction with the radial fascial skin flap can be performed. If the defect size is more than 71 cm3, reconstruction with musculocutaneous alt flap can be the method of choice.

IMPLEMENTASI MODEL ACCELERATED FAILURE TIME (AFT) BERDISTRIBUSI LOG-LOGISTIK PADA PASIEN PENYAKIT JANTUNG BAWAAN

Log-Logistic Accelerated Failure Time (AFT) model is survival analysis that is used when the survival time follows Log-Logistic distribution. Log-Logistic AFT model can be used to estimate survival time, survival function, and hazard function. Log-Logistic AFT model was formed by regressing covariates linierly against the log of survival time. Regression coefficients are estimated using maximum likelihood method. This study uses data from Atrial Septal Defect (ASD) patients, which is a congenital disease with a hole in the wall that separates the top of two chambers of the heart by using sensor type III. Survival time as the response variable, that is the time from patient was diagnosed with ASD until the first relapse and uses age, gender, treatment status (catheterization/surgery), defect size that is the size of the hole in the heart terrace, pulmonary hypertension status, and pain status as predictor variables. The result showed that variable gender, treatment status, defect size, pulmonary hypertension status, and pain status affect the first recurrence of ASD patients, so it is found that category of female, untreated patient, defect size ≥12mm, having pulmonary hypertension, having chest pain tend to have first recurrence sooner than the other category.

Improving Fatigue Limit and Rendering Defects Harmless through Laser Peening in Additive-Manufactured Maraging Steel

Additive-manufactured metals have a low fatigue limit due to the defects formed during the manufacturing process. Surface defects, in particular, considerably degrade the fatigue limit. In order to expand the application range of additive-manufactured metals, it is necessary to improve the fatigue limit and render the surface defects harmless. This study aims to investigate the effect of laser peening (LP) on the fatigue strength of additive-manufactured maraging steel with crack-like surface defects. Semicircular surface slits with depths of 0.2 and 0.6 mm are introduced on the specimen surface, and plane bending-fatigue tests are performed. On LP application, compressive residual stress is introduced from the specimen surface to a depth of 0.7 mm and the fatigue limit increases by 114%. In a specimen with a 0.2 mm deep slit, LP results in a high-fatigue-limit equivalent to that of a smooth specimen. Therefore, a semicircular slit with a depth of 0.2 mm can be rendered harmless by LP in terms of the fatigue limit. The defect size of a 0.2 mm deep semicircular slit is greater than that of the largest defect induced by additive manufacturing (AM). Thus, the LP process can contribute to improving the reliability of additive-manufactured metals. Compressive residual stress is the dominant factor in improving fatigue strength and rendering surface defects harmless. Moreover, the trend of the defect size that can be rendered harmless, estimated based on fracture mechanics, is consistent with the experimental results.

Large segmental defects in midshaft clavicle nonunion treated with autologous tricortical iliac crest bone graft

Background To evaluate the use of intercalary iliac crest bone graft in the treatment of clavicle nonunion with a large segmental bone defect (3–6 cm). Methods This retrospective study evaluated patients with large segmental bone defects (3–6 cm) after clavicle nonunion, treated with open reposition internal fixation and iliac crest bone graft between February 2003 and March 2021. At follow-up the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire was administered. A literature search was performed to provide an overview of commonly used graft types per defect size. Results We included five patients treated with open reposition internal fixation and iliac crest bone graft for clavicle nonunion with a median defect size of 3.3 cm (range 3–6 cm). Union was achieved in all five, and all pre-operative symptoms resolved. The median DASH score was 23 out of 100 (IQR 8-24). An extensive literature search revealed that there are no studies describing the use of an used iliac crest graft for defects larger than 3 cm. Instead, a vascularized graft was typically used to treat defects sizes between 2.5 and 8 cm. Discussion An autologous non-vascularized iliac crest bone graft can be safely used and is reproducible to treat a midshaft clavicle non-union with a bone defect between 3 and 6 cm.

Time Matters: Knee Cartilage Defect Expansion and High-Grade Lesion Formation while Awaiting Autologous Chondrocyte Implantation

Objective The objective of this study was to assess potential risk factors, including time delay until implantation, for knee cartilage defect expansion or new high-grade defect formation between biopsy and Autologous Chondrocyte Implantation (ACI) or Matrix Autologous Chondrocyte Implantation (MACI). Study design Consecutive knee ACI and MACI cases by a single surgeon ( n = 111) were reviewed. The relationship between time between biopsy and staged implantation and (1) progression in primary cartilage defect size and (2) development of a new high-grade (Outerbridge grade ≥3) cartilage defect were determined with adjustment for demographics, body mass index, smoking status, coronal alignment, initial cartilage status, and prior surgery. Results Average size of the primary defect at time of biopsy was 4.50 cm2. Mean time to chondrocyte implantation was 155 days. Defect expansion increased 0.11 cm2 (standard error = 0.03) per month delay to implantation ( P = 0.001). Independent predictors of defect expansion were male sex, smaller initial defect size, and delay to implantation (adjusted mean = 0.15 cm2 expansion per month). A total of 16.2% of patients ( n = 18/111) developed a new high-grade defect. Independent predictors of a new secondary defect were Outerbridge grade 2 changes (vs. 0-1) on the surface opposing the index defect and delayed implantation (per month increase, adjusted odds ratio = 1.21, 95% confidence interval: 1.01-1.44; P = 0.036). Conclusions Patients undergoing 2-stage cell-based cartilage restoration with either ACI or MACI demonstrated long delays between stages of surgery, placing them at risk for expanding defects and development of new high-grade cartilage defects. Patients who were male, had smaller initial defect size, and longer time between surgeries were at greater risk for defect expansion. Level of Evidence III, retrospective comparative study.

Remained Large Bone Fragment of Bony Bankart Lesion in Shoulders With a Subcritical Glenoid Defect at Recurrent Anterior Instability

Background: A preoperative glenoid defect of 13.5% or larger is recognized as a subcritical glenoid defect at arthroscopic Bankart repair (ABR) for collision/contact athletes or military personnel. Purpose: To clarify the prevalence and size of remaining bone fragments in shoulders with a subcritical glenoid defect at recurrent anterior instability and to investigate the influence on postoperative recurrence after ABR for younger competitive athletes. Study Design: Cohort study; Level of evidence, 4. Methods: The study included 96 shoulders with recurrent instability that underwent ABR between July 2011 and March 2018 for shoulders with a subcritical glenoid defect. The patients were divided into 2 groups according to the glenoid defect size (13.5%-<20%, medium; ≥20%, large). The bone fragment size in each defect group was retrospectively investigated and classified into 4 groups (no, 0%; small, >0%-<5%; medium, 5%-<10%; large, ≥10%). The postoperative recurrence rate for each combination of glenoid defect size and bone fragment size was investigated for competitive athletes aged <30 years. The fragments, when present, were repaired to the glenoid. Results: The glenoid defect size was 13.5%-<20% in 60 shoulders (medium defect group) and ≥20% in 36 shoulders (large defect group). The mean bone fragment size was 6.7% ± 5.1% and 8.9% ± 4.9%, respectively ( P = .042). In the medium defect group, there were 15 shoulders (25%) without a bone fragment, 6 shoulders (10%) with a small fragment, 23 shoulders (38.3%) with a medium fragment, and 16 shoulders (26.7%) with a large fragment. In the large defect group, the respective numbers were 2 shoulders (5.6%), 6 shoulders (16.7%), 14 shoulders (38.9%), and 14 shoulders (38.9%). A medium or large bone fragment was more common in the large defect group ( P = .252). Among 64 younger competitive athletes who underwent ABR with a minimum of 2 years of follow-up, postoperative recurrence was recognized in 7 of 38 (18.4%) athletes in the medium defect group, but it was not recognized in any of the 26 athletes in the large defect group ( P = .036). Postoperative recurrence was recognized in 4 of 12 (33.3%) athletes with a small fragment or no fragment and in 3 of 52 (5.8%) athletes with a medium or large fragment ( P = .019). Conclusion: A larger bone fragment frequently remained in shoulders with a subcritical glenoid defect at recurrent instability. The postoperative recurrence rate after ABR for younger competitive athletes was low when a remaining larger bone fragment was repaired.

Pediatric Cranioplasty Using Hydroxyapatite Cement: A Retrospective Review and Preliminary Computational Model

IIntroduction Cranioplasty is a standard technique for skull defect repair. Restoration of cranial defects is imperative for brain protection and allowing for homeostasis of cerebral spinal fluid within the cranial vault. Calcium phosphate hydroxyapatite (HA) is a synthetic-organic material that is commonly used in cranioplasty. We evaluate a patient series undergoing HA cement cranioplasty with underlying bioresorbable mesh for various cranial defects and propose a preliminary computational model for understanding skull osteointegration. Methods A retrospective review was performed at the institution for all pediatric patients who underwent HA cement cranioplasty. 17 patients were identified and success of cranioplasty was determined based on clinical and radiographic follow-up. A preliminary computational model was developed using bone growth and scaffold decay equations from previously published literature. The model was dependent on defect size and shape. Patient data was used to optimize the computational model. Results Seventeen patients were identified with an average age of 6±5.6 years. Average defect size was 11.7±16.8 cm2. Average time to last follow-up CT scan was 10±6 months. Three patients had failure of cranioplasty, all with a defect size above 15 cm2. The computational model developed shows a constant decay rate of the scaffold, regardless of size or shape. The bone growth rate was dependent on the shape and number of edges within the defect. Thus, a star-shaped defect obtained a higher rate of growth than a circular defect because of faster growth rates at the edges. The computational simulations suggest that shape and size of defects may alter success of osteointegration. Conclusion Pediatric cranioplasty is a necessary procedure for cranial defects with a relatively higher rate of failure than adults. Here, we use hydroxyapatite cement to perform the procedure while creating a preliminary computational model to understand osteointegration. Based on the findings, cranioplasty shape may alter rate of integration and lead to higher success rates.

The Efficacy of Local Flaps in the Treatment of Traumatic Scalp Defects

Background Scalp defects represent a therapeutic challenge. The aim of this study is to present our experience with local and regional flaps in the treatment of trauma-induced scalp defects. Furthermore, a comparison with other surgical techniques was performed. Methods A retrospective evaluation of patient records was performed. Only patients who underwent surgery using local flaps between January 2010 and September 2020 due to traumatic scalp defects were included in the study. Results In all, 10 cases were identified (3 females, 7 males, average age at surgery of 46.5 years [range: 18–82 years]). Six patients underwent surgery due to tissue defects and four due to scar keloids. Three patients experienced minor postoperative complications, one of which required additional surgery. The mean defect size was 35.75 cm2 (range: 4–79 cm2) among the four patients where the defect size could be determined retrospectively. The mean inpatient follow-up was 12.4 days (range: 2–34 days). Conclusions Local flaps can be widely used. In carefully selected cases, they have the fewest disadvantages of all surgical techniques. In our experience, large angiosomes of the main scalp arteries allow the treatment of defects larger than 30 cm2 with local flaps. Our experience also suggests that the dimensions of flap length to flap width can exceed a ratio of 2:1 in the scalp.