Conventional Wedge Research Articles

Complication analysis after angle-stable CW and OW high tibial osteotomy

High tibial osteotomy (HTO) is agood joint-preserving alternative to joint replacement in the treatment of isolated medial varus gonarthrosis. It is, however, accompanied by anumber of complications, which can compromise the outcome of the treatment. Analysis and comparison of the complication structure after angle-stable navigated closed wedge (CW) HTO and conventional angle-stable open wedge (OW) HTO, as well as determination of influence factors. 281 HTO (187 CW- and 94OWHTO) were analyzed retrospectively. Age, sex, BMI, time of surgery and radiological parameters were included as possible influence factors. A statistical analysis was performed with binary logistic regression. An overall complication rate of 21.4% was revealed (25.1% after CW- and 13.8% after OWHTO, p = 0.02); the major complications occurred after 13.9% CW- and 10.6% OWHTO (p = 0.27); minor complications were observed after 11.2% CW- and 3.2% OWHTO (p = 0.03). This difference results from complications specific to CWHTO (peroneal lesions and pseudarthrosis fibulae). The incidence of pseudarthrosis tibiae was equal in both procedures (7.5%). Age ≥ 52years and body mass index (BMI) ≥ 30 kg/m2 were the relevant predictors for mechanical complications after CWHTO; these were not relevant for OWHTO. The correct patient selection is essential to avoid postoperative complications after HTO. The overall complication rates are lower after OWHTO, mainly through the avoidance of complications typical for CWHTO. OWHTO offers a wider choice with respect to the selection of patients.

CLEAN-NET: a modified laparoendoscopic wedge resection of the stomach to minimize the sacrifice of innocent gastric wall.

To avoid excessive sacrifice of the tissue surrounding the submucosal tumor in gastric wedge resection with a stapling device, we perform a "combined laparoscopic and endoscopic approach for neoplasia with a nonexposure technique" (CLEAN-NET). Herein the operative technique of CLEAN-NET is described and its short-term outcomes in 50 patients are evaluated. Between December 2015 and July 2017 CLEAN-NET was performed in 50 patients with gastric submucosal tumors. During the operation, the seromuscular layer above the tumor is dissected, while the mucosa is kept unbroken. When seromuscular layer is dissected all around the tumor, the full layer is lifted, and the mucosa is stretched. The mucosa is then transected with a stapling device to execute full-thickness resection of the specimen. Finally, the seromuscular defect is repaired by hand-sewn suture. The hospital records of the 50 patients were reviewed to assess the outcomes. The margin width was compared with those measured in another group with 19 patients, who underwent conventional wedge resection with a stapling device. The operation was completed as CLEAN-NET and the tumor was resected en-bloc without rupture in all patients. The average operation time ranged from 50 to 220min with an average of 105.4min. The post-operative course was uneventful. Microscopically the surgical margin was tumor-negative (R0 resection) in all cases. The margin width in the CLEAN-NET group was smaller than that in the wedge resection group (5.4mm ± 2.5 vs. 33.1mm ± 14.7). CLEAN-NET can be performed safely with an acceptable operation time. CLEAN-NET can be a useful option in the laparoscopic surgical treatment of gastric submucosal tumors, when excessive sacrifice of the healthy gastric wall surrounding the endophytic tumor should be avoided.

Using a state-dependent constitutive model in strain wedge method for laterally loaded piles in sand

Strain Wedge Method is an effective technique for the analysis of laterally loaded flexible piles in sand. In this method, the three-dimensional soil-pile interaction problem is reduced to the problem of one-dimensional beam on elastic foundation. Various modifications have been applied to the conventional Strain Wedge Method to promote its predictive capacity for different problems. Nevertheless, in the existing Strain Wedge Methods, because the impact of soil state on the stress-strain-strength behavior of granular soils is ignored, multiple calibrations for a wide domain of soil densities are required. To overcome this drawback, a simple but versatile state-dependent constitutive model is implemented in the Strain Wedge Method. It is shown that the modified Strain Wedge Method can effectively simulate the response of laterally loaded model piles embedded in sands of loose, medium, and dense states using a single set of parameters.

Laparoscopic and endoscopic cooperative surgery for gastric tumors: Perspective for actual practice and oncological benefits.

Laparoscopic and endoscopic cooperative surgery (LECS) is a surgical technique that combines laparoscopic partial gastrectomy and endoscopic submucosal dissection. LECS requires close collaboration between skilled laparoscopic surgeons and experienced endoscopists. For successful LECS, experience alone is not sufficient. Instead, familiarity with the characteristics of both laparoscopic surgery and endoscopic intervention is necessary to overcome various technical problems. LECS was developed mainly as a treatment for gastric submucosal tumors without epithelial lesions, including gastrointestinal stromal tumors (GISTs). Local gastric wall dissection without lymphadenectomy is adequate for the treatment of gastric GISTs. Compared with conventional simple wedge resection with a linear stapler, LECS can provide both optimal surgical margins and oncological benefit that result in functional preservation of the residual stomach. As technical characteristics, however, classic LECS involves intentional opening of the gastric wall, resulting in a risk of tumor dissemination with contamination by gastric juice. Therefore, several modified LECS techniques have been developed to avoid even subtle tumor exposure. Furthermore, LECS for early gastric cancer has been attempted according to the concept of sentinel lymph node dissection. LECS is a prospective treatment for GISTs and might become a future therapeutic option even for early gastric cancer. Interventional endoscopists and laparoscopic surgeons collaboratively explore curative resection. Simultaneous intraluminal approach with endoscopy allows surgeons to optimizes the resection area. LECS, not simple wedge resection, achieves minimally invasive treatment and allows for oncologically precise resection. We herein present detailed tips and pitfalls of LECS and discuss various technical considerations.

Composite wavelength tunable wedged interference structures with increased free spectral range

In the present paper, we propose a compact composite wedge interference structure by combining wedges with different geometry. We use interferential wedges with optical thickness from several micrometers to several hundred micrometers and apex angles of the order of tens microradians. The aim of the conducted study is to prove that such a structure exhibits improved optical properties in comparison to a conventional wedge. We have carried out simulations and experiments with a structure built from two wedges. We have shown that, instead of multiple transmission peaks observed for a single interferential wedge, the composite structure provides selection of a single resonance in transmission within the impact area of a large diameter monochromatic beam and enables wavelength tuning when a small diameter multi-wavelength beam is used. The first property ensures analysis of light beams characterized with a wide spectrum. The second feature allows for increase of the wavelegth tuning range at keeping spectrally narrow transmission peak if the structure is formed by a thin and a thick interferential wedges. Two such structures have been realized using a technique which we have developed. The experiments made with this structures show that the produced transmission peak is narrowed spatially and spectrally at the expense of lower transmission which achieves 50–60% of transmission ensured by the used interferential wedges.

Development of a novel fatigue test method for cord-rubber composites

Fatigue testing of cord-rubber composites is of significant interest as components manufactured from these materials are typically subjected to repeated loading during service. In this work, initial fatigue tests on a single carbon cord reinforced hydrogenated nitrile butadiene rubber (CC-HNBR) model composite were undertaken using conventional wedge grips which are routinely employed for fatigue testing of cord-rubber composites. Damage evolution was monitored using thermal imaging, while post-failure modes were evaluated using scanning electron microscopy (SEM). Finite element analysis (FEA) was performed to understand the stress state in the gripping region. The observed failure mode in wedge grips based testing was found to be interfacial debonding as a consequence of shear stress concentrations induced by the grips, leading to a significant underestimation of fatigue life. Consequently, an alternative bollard based test methodology was developed for cord-rubber composites. Fatigue data generated using this novel bollard test set-up was compared with data obtained by using conventional wedge grips. Bollard-based testing resulted in tensile fatigue behaviour dominated by cord failure rather than failure by interfacial debonding during accelerated laboratory fatigue testing, making the developed test methodology better suited for the characterisation of intrinsic fatigue behaviour of cord-rubber composites.

Spatial Development of the Dipolarization Region in the Inner Magnetosphere

AbstractThe present study examines dipolarization events observed by the Van Allen Probes within 5.8 RE from Earth. It is found that the probability of occurrence is significantly higher in the dusk‐to‐midnight sector than in the midnight‐to‐dawn sector, and it deceases sharply earthward. A comparison with observations made at nearby satellites shows that dipolarization signatures are often highly correlated (c.c. >0.8) within 1 hr in magnetic local time (MLT) and 1 RE in RXY, and the dipolarization region expands earthward and westward in the dusk‐to‐midnight sector. The westward expansion velocity is estimated at 0.4 hr (in MLT) per minute, or 60 km/s, which is consistent with the previously reported result for geosynchronous dipolarization. The earthward expansion is apparently less systematic than the westward expansion. Its velocity is estimated at 50 km/s (0.5 RE/min), comparable to the westward expansion velocity, but it is suggested that the earthward expansion slows down as the dipolarization region approaches Earth, and it eventually stops. This idea is consistent with the earthward reduction of the occurrence probability of dipolarization events. Whereas this earthward expansion is difficult to explain with the conventional wedge current system, it may be understood in terms of a current system with two wedges, one with the R1 polarity outside and the other with the R2 polarity closer to Earth. For such a current system the region of dipolarization is confined in radial distance between the two wedge currents, and it is considered to expand earthward as the R2‐sense wedge moves earthward along with injected plasma.

Wide slab is useful for routine quality control of MRI slice thickness

Although slice thickness accuracy is important for the performance of magnetic resonance imaging systems, long scan times are required to perform reliable measurements. Inclined slabs and wedges are conventionally used as test devices to obtain slice profiles. In this study, a novel dedicated device with a widened slab was created, and its efficacy was compared with that of a conventional wedge. The signal-to-noise ratio (SNR) of the profile and the coefficient of variation (CV) of the measured slice thickness were measured. Wide slab usage showed sufficient SNR by averaging multiple profile lines, even with single acquisition. Therefore, it is possible to substantially shorten the measurement time. When ≥ 20 lines were averaged, CV was < 1%. Furthermore, a 200-mm slab width enabled evaluation of the positional dependence of slice thickness in a single imaging. Thus, quality control of MRI slice thickness can be easily implemented with this device.

Detailed Study on the Failure of the Wedge Calibration Method at Nanonewton Setpoints for Friction Force Microscopy

The wedge calibration method is the most popular calibration technique in friction force microscopy for converting raw lateral laser deflection signals (in volt) into forces (in newton). Recent trends in nanotribology demand the use of the method at nanonewton (nN) force ranges; however, this method fails at these small forces. The objective of the present work is to identify the reason why the conventional wedge calibration method fails at nN force ranges. We found that the equation used in the model in this method amplifies experimental errors by orders of magnitude only at small setpoints purely due to its mathematical expression. This low tolerance against experimental errors in nanonewton force ranges is the reason for the failure. We identified that the condition, under which the method operates accurately, is adhesion ≪ setpoint. Discovery of this operation range (adhesion ≪ setpoint) is important because performing the calibration under other conditions can wrongly calibrate the system by orders o...

High contrast laser beam collimation testing using two proximately placed holographic optical elements

Accuracy in laser beam collimation is very important in systems used for precision measurements. The present work reports a technique for collimation testing of laser beams using two proximately placed holographic optical elements (HOEs). The required HOEs are designed and fabricated such that upon illumination with the test beam, they release two laterally sheared wavefronts, at desired angles from the directly transmitted beam, that superimpose each other to generate straight interference fringes. Deviation from the collimation of the test beam results in orientation of these otherwise horizontal fringes. The novelty of this setup comes from the fact that HOEs are lightweight, as well as easy to fabricate as compared to conventional wedge plates used for collimation testing, and generate high contrast fringes compared to other interferometry, holography, Talbot and Moiré based techniques in a compact manner. The proposed technique is experimentally validated by measuring the orientation of fringes by an angle of 16.4° when a collimating lens of focal length 200 mm is defocused by 600 μm. The accuracy in the setting of this collimation position is obtained to be 10 μm.

Very Distal Radius Wedge Osteotomy for Kienböck's Disease: Case Series.

Radius osteotomy is one of the standard surgical procedures for the treatment of Kienböck's disease. Unfortunately, radius osteotomy can result in an incongruous distal radio-ulnar joint (DRUj) postoperatively, because the procedure is performed proximal to the DRUj. A very distal radius wedge osteotomy was performed as a 15-degree lateral closing wedge osteotomy with the apex of the wedge distal to that of conventional lateral closing wedge osteotomy; this procedure was developed to avoid postoperative incongruous DRUj. We performed this procedure on 6 patients (stage III-A: 1, stage III-B: 5) with a mean age of 49 years. Clinical and radiographic evaluations were performed at a mean follow-up of 32 months. Wrist pain disappeared in all patients. Mean grip strength improved from 35% to 87% of the contralateral side (p = 0.0255). Mean range of motion, measured as flexion-extension arc, improved from 93 to 128 degrees. Nakamura's score was good in all patient. Mean lunate covering ratio increased from 61% to 90% (p = 0.0151) and mean sigmoid notch inclination angle, a radiographic parameter of DRUj congruency, was not significantly different between pre-operative and final follow-up evaluation. No clinical or radiographic DRUj osteoarthritis findings were observed. Our procedure of very distal radius wedge osteotomy provided satisfactory clinical results without an incongruous DRUj. This technique might prevent the occurrence of postoperative DRUj osteoarthritis.

Improved wedge method for the measurement of sub-millimeter slice thicknesses in magnetic resonance imaging.

The standard method for measuring the slice thickness of magnetic resonance images uses the inclined surface of a wedge (wedge method); it is sensitive to small increases in noise because of the differentiation of the edge response function (ERF) required. The purpose of this study was to improve the wedge method by fitting a curve to the ERF. The curve-fit function was obtained by convolving an ideal ERF (a ramp function) with a Gaussian function to represent ERF blurring. Measurements of 5- and 3-mm slice thicknesses were performed on a 3T scanner using the conventional wedge method, the improved wedge method, and another standard method using an inclined slab (slab method). Subsequently, 0.5- and 0.25-mm slice thicknesses from multiple slices acquired using a three-dimensional sequence were measured using the improved wedge method. When measuring 5-mm slices, the differences in measurements obtained using the improved wedge method and the conventional slab and wedge methods were very small: <0.6% of the 5-mm slice thickness. The difference was ≤1.7% for 3-mm slices. For 0.5- and 0.25-mm slices, the mean values obtained using the improved wedge method were 0.543±0.007mm and 0.247±0.015mm, with a 1.2 and 5.9% coefficient of variation across slices, respectively. The improved wedge method is valid and potentially applicable to the measurement of sub-millimeter slice thicknesses.

A design of high optical efficiency wedge type light guide plate adopting twin inclined cylindrical surface

AbstractWe propose wedge type light guide plate (LGP) adopting twin inclined cylindrical surfaces (TICS) at the incident part of a LGP. It has higher optical efficiency than conventional wedge type LGP. In dimension of LGP which the thickness of incident part is 1.5 mm and that of luminance part is 0.7 mm, the optical efficiency of wedge type LGP adopting TICS is expected to be 96% in comparison with a normal flat LGP. In addition, there is an advantage to reduce the non‐uniformity of vicinity of light emitted diodes (LEDs) by TICS reflecting light laterally. However, it is necessary that the LED centers are aligned with the intersections of TICS. The misalignment of LED causes non‐uniformity of optical profile that is slightly larger than a normal LGP.

Current status and challenges in sentinel node navigation surgery for early gastric cancer.

Although a number of feasibility studies for sentinel node (SN) concepts in gastric cancer have been conducted since 2000, there remains a debate regarding detailed detection techniques and oncological safety. Two important multicenter phase II clinical trials were performed in Japan that used different methods and reached different conclusions; one confirmed acceptable results with a false-negative rate of 7%, and the other showed an unacceptably high false-negative rate of 46.4%. The Sentinel Node Oriented Tailored Approach (SENORITA) trial is a multicenter randomized controlled phase III trial being performed in Korea. Patient enrollment is now complete and the long-term results are currently awaited. Recently, an image-guided SN mapping technique using infrared ray/fluorescence was introduced. This method might be a promising technology because it allows the clear visualization of SNs. With regard to the primary tumor, the non-exposed endoscopic wall-inversion surgery technique and non-exposure endolaparoscopic full-thickness resection with simple suturing technique have been reported. These methods prevent abdominal infection and tumor seeding and can be good alternatives to conventional laparoscopic gastric wedge resection. For indications, SN navigation surgery can be extended to patients who underwent non-curative endoscopic resection. Although a few studies have been performed on these patients, sentinel concepts may be beneficial to patients as they omit the need for additional gastrectomy. SN navigation surgery can lead to actual organ-preserving surgery and plays a key role in improving the quality of life of patients with early gastric cancer in the future.

Laparoscopy-assisted endoscopic full-thickness resection for gastric subepithelial tumors originated from the muscularis propria layer: a pilot study with literature review

Objective: Laparoscopy-assisted endoscopic full-thickness resection (LAEFTR) has been suggested as an alternative to laparoscopic wedge resection in the treatment of gastric subepithelial tumors (SETs). It is expected to minimize the resection of the tissue surrounding the tumors and maintain the function of the remnant stomach. Here, we performed a prospective pilot study to evaluate the efficacy of laparoscopy-assisted endoscopic full-thickness resection (LAEFTR) for patients with gastric SETs.Material and methods: We enrolled twelve patients who were diagnosed with gastric SETs with an intraluminal growth pattern or which is located in the gastric antrum between October 2011 and September 2013. LAEFTR was performed endoscopically using an endoscopic knife to make an incision half way around the tumor circumference and a laparoscopic resection around the remaining tumor circumference, followed by its laparoscopic removal. The feasibility, safety, and effectiveness of LAEFTR for gastric SETs were evaluated.Results: The median size of the tumors in twelve patients was 22 mm (21–33). Of the 12 patients, 8 received LAEFTR, while the others underwent conventional laparoscopic wedge resection, since their tumor outlines were clearly visible in laparoscopic view. In 8 patients who underwent LAEFTR, the mean total operation time (endoscopic procedure time/laparoscopic procedure time) were 117 (37/41) min. The tumors were completely resected with clear margin, and there was no perioperative and postoperative complications.Conclusions: LAEFTR currently seems to be the ideal treatment modality of intraluminal gastric SETs where their resection margins are difficult to define under laparoscopic guidance alone.

Left-sided breast radiotherapy after conservative surgery: comparison of techniques between volumetric modulated arc therapy, forward-planning intensity-modulated radiotherapy and conventional technique

AbstractObjectiveThis study was conducted for comparison of techniques between volumetric modulated arc therapy (VMAT), forward-planning intensity-modulated radiotherapy (FIMRT) and conventional technique for left-sided breast radiotherapy after conservative surgery.MethodsIn all, 20 postoperative left breast carcinoma patients were included in this study. In all plans the planning target volume (PTV) was the breast tissue with appropriate margin as per our institutional protocol. The contouring was done on a Monaco Sim (V5.00.02) contouring workstation. All patient were planned using partial arc VMAT in Monaco treatment planning system (TPS) (V5.00.02) and treated on Elekta Synergy linear accelerator. The 3D conformal radiotherapy (3DCRT) and FIMRT planning were done in CMS XIO (V5.00.01.1) TPS. The 3DCRT planning consisted of conventional medial and tangential wedge portals with multileaf collimator field shaping conforming to the target volume. For all the plans generated the following metrics were scored: V105%, V100%, V95%, mean dose (for PTV), V5%, V20%, D2cc and mean dose (for organs at risk).ResultsThe mean PTV volume for 20 patients was 1,074·6±405·1 cc. The highest PTV dose coverage was observed in the 3DCRT technique with 94·1±1·8% of the breast PTV receiving 95% of the prescription dose (V95%). However, it was also observed that this technique resulted in 21·3±10% of the PTV receiving more than 105% of the prescription dose (V105%), which was highest among the three techniques. In contrast, VMAT yielded lowest V95% of 93·0±1·8 and 3·3±5·5% of V105%.ConclusionThis study concluded equivalent result between FIMRT and VMAT. However, VMAT was found to be the choice of radiotherapy technique as it produces lesser dose distribution to heart compared with any other technique.

The use of sternal wedge osteotomy in pectus surgery: when is it necessary?

The Ravitch procedure is a well-established surgical procedure for correction of chest wall deformities. Sternal wedge osteotomy is an important part of this procedure. We studied the incidence of wedge osteotomy with respect to the type of chest wall deformity in patients undergoing surgical correction with the use of a recently developed chest wall stabilization system. A total of 47 patients, 39 (83%) male and 8 (17%) female with a mean age of 14.9 ± 2.1 years, underwent the Ravitch procedure. Twenty-four (51.1%) had pectus carinatum, 19 (40.4%) had pectus excavatum, and 4 (8.5%) had pectus arcuatum. A conventional or oblique sternal wedge osteotomy was performed as indicated, followed by chest wall stabilization using the MedXpert system. Of the 47 patients, 27 (57.4%) had a sternal wedge osteotomy. All cases of pectus arcuatum and redo cases underwent sternal wedge osteotomy. Pectus excavatum cases tended to have a greater incidence of wedge osteotomy compared to pectus carinatum cases (68.4% vs. 41.7%, p = 0.052). Patients with more resected ribs had a greater rate of wedge osteotomy (63.4%) compared to those with fewer resected ribs (16.7%, p = 0.043). A sternal wedge osteotomy is more commonly performed in patients with pectus excavatum compared to those with pectus carinatum. All redo and pectus arcuatum cases need a wedge osteotomy for proper correction. Wedge osteotomy is very likely in more aggressive corrections with more rib resections.

Mono- and Dinuclear Macrocyclic Calcium Complexes as Platforms for Mixed-Metal Complexes and Clusters.

Mono- and dinuclear calcium complexes of the Schiff-base macrocycles H4L have been prepared and characterized spectroscopically and crystallographically. In the formation of Ca(THF)2(H2L(1)), Ca2(THF)2(μ-THF)(L(1)), and Ca2(THF)4(L(2)), the ligand framework adopts a bowl-shaped conformation instead of the conventional wedge, Pacman-shaped structure as seen with the anthracenyl-hinged complex Ca2(py)5(L(3)). The mononuclear calcium complex Ca(THF)2(H2L(1)) reacts with various equivalents of LiN(SiMe3)2 to form calcium/alkali metal clusters and dinuclear transition metal complexes when reacted subsequently with transition metal salts. The dinuclear calcium complex Ca2(THF)2(μ-THF)(L(1)), when reacted with various equivalents of NaOH, is shown to act as a platform for the formation of calcium/alkali metal hydroxide clusters, displaying alternate wedged and bowl-shaped conformations.

SU‐E‐J‐172: Bio‐Physical Effects of Patients Set‐Up Errors According to Whole Breast Irradiation Techniques

Purpose:The dose‐related effects of patient setup errors on biophysical indices were evaluated for conventional wedge (CW) and field‐in‐field (FIF) whole breast irradiation techniques.Methods:The treatment plans for 10 patients receiving whole left breast irradiation were retrospectively selected. Radiobiological and physical effects caused by dose variations were evaluated by shifting the isocenters and gantry angles of the treatment plans. Dose‐volume histograms of the planning target volume (PTV), heart, and lungs were generated, and conformity index (CI), homogeneity index (HI), tumor control probability (TCP), and normal tissue complication probability (NTCP) were determined.Results:For “isocenter shift plan” with posterior direction, the D95 of the PTV decreased by approximately 15% and the TCP of the PTV decreased by approximately 50% for the FIF technique and by 40% for the CW; however, the NTCPs of the lungs and heart increased by about 13% and 1%, respectively, for both techniques. Increasing the gantry angle decreased the TCPs of the PTV by 24.4% (CW) and by 34% (FIF). The NTCPs for the two techniques differed by only 3%. In case of CW, the CIs and HIs were much higher than that of the FIF in all cases. It had a significant difference between two techniques (p&lt;0.01). According to our results, however, the FIF had more sensitive response by set up errors rather than CW in bio‐physical aspects.Conclusions:The radiobiological‐based analysis can detect significant dosimetric errors then, can provide a practical patient quality assurance method to guide the radiobiological and physical effects.

Oncologic Safety of Laparoscopic Wedge Resection with Gastrotomy for Gastric Gastrointestinal Stromal Tumor: Comparison with Conventional Laparoscopic Wedge Resection.

PurposeVarious laparoscopic wedge resection (LWR) techniques requiring gastrotomy for gastrointestinal stromal tumors (GISTs) of the stomach have been applied to facilitate tumor resection and preserve the remnant gastric volume. However, there is the possibility of cancer cell dissemination during these procedures. The aim of this study was to assess the oncologic safety of LWR with gastrotomy (LWR-G) compared to LWR without luminal exposure.Materials and MethodsClinicopathologic and operative results of 193 patients who underwent LWR for gastric GIST were retrospectively analyzed from 2003 to 2013. We stratified the patients into two groups: LWR-G and LWR without gastrotomy (LWR-C). Clinicopathologic features, short-term outcomes, and long-term outcomes were compared.ResultsA total of 26 patients underwent LWR-G, and 167 patients underwent LWR-C. The LWR-G group showed significantly more anterior wall-located (n=10, 38.5%), intraluminal (n=20, 76.9%), and ulcerative (n=13, 50.0%) tumors than the LWR-C group (n=33, 19.8%; n=96, 57.5%; n=46, 27.5%, respectively). Postoperative short-term outcomes did not differ between the two groups. When tumor staging was compared, no statistical difference was noted. There was no recurrence in the LWR-G group, while 2 patients in the LWR-C group experienced recurrence. The two recurrences in the LWR-C group were found in the liver and in the remnant stomach at 63 and 12 months after the operation, respectively. No gastric GIST-related death was recorded in any group during the study period.ConclusionsLWR-G for gastric GIST is an oncologically safe procedure even for masses with ulcerations.