Retroperitoneal Research Articles

A case presentation on rare case of retroperitoneal liposarcoma

Retroperitoneal liposarcoma is a rare biologically heterogeneous tumor that present considerable challenges due to its size and deep location.as consequences, the majority of the patients with high grade rpls will develop locally recurrent disease following surgery, and this constitutes the cause of death in most patients. Symptoms are usually nonspecific and they do not appear until the tumor becomes very large. Early diagnosis is difficult as there is an absence of specific clinical presentations. A painless abdominal lump that enlarges in a long period of time in an adult is the most common history of patient. Metastasis at initial presentation is uncommon. Surgical exploration is needed for the final pathological diagnosis. Case presentation: we report a case of 56 year old male patient who underwent a complete surgical excision of pleomorphic retroperitoneal liposarcoma. Retroperitoneal liposarcomas are rare soft tissue sarcoma. They often cause minimal or no symptoms and can reach a significant size, growing undetected in retroperitoneal space before invading or compressing surrounding organs, eventually leading to clinical symptoms. Complete surgical excision is the mainstay of treatment. Whenever possible, macroscopically complete resection should be aimed at, often requiring en bloc removal of adjacent structures such as the abdominal wall, psoas, or paravertebral muscles.

The Character of Purulent-Inflammatory Diseases of The Retroperitoneal Region

Conducted a retrospective data analysis of 439 patient records with purulent-inflammatory diseases of the retroperitoneal space, receiving inpatient treatment in the department of purulent surgery of the multidisciplinary clinic of the Tashkent Medical Academy from 2010 to 2022, in order to select the observation group.All patients, along with general clinical laboratory studies, underwent MSCT and ultrasound of the retroperitoneal region before the start of the treatment complex to determine the operational tactics of treatment. At the same time, a limited pathological focus (abscess) was detected in 28.7% of cases, signs of phlegmon were noted in 51.4% of cases, and combined types or postoperative fistulas were observed in 19.9% of cases.

Perirenal fat thickness is a powerful predictor for surgical outcomes of transperitoneal laparoscopic adrenalectomy.

Laparoscopic adrenalectomy has been the gold standard surgical procedure. However, the adaptation criteria for malignant tumors and predictors of perioperative outcomes are not well defined. Therefore, this study tried to identify valid predictors for perioperative outcomes of laparoscopic adrenalectomy and consider the adaptation criteria. We retrospectively reviewed the preoperative and perioperative data of 216 patients who underwent transperitoneal laparoscopic adrenalectomy in our hospital. Preoperative factors associated with perioperative outcomes were analyzed using multiple regression analysis. Among 216 patients, 165 (76.4%), 26 (12.0%), and 25 (11.6%) were suspected of having benign tumors, pheochromocytoma, and malignant tumors, respectively. Median tumor size was 25.0 mm (interquartile range 18.0-35.0); median perirenal fat thickness was 9.2 mm (interquartile range 4.9-15.6) on preoperative computed tomography scans. The median operative time was 145.5 min (interquartile range 117.5-184.0) and the median estimated blood loss was 0.0 mL (interquartile range 0.0-27.3). Perirenal fat thickness (p < 0.001), tumor size (p < 0.001), and malignant tumors (p = 0.020) were associated with operative time, and perirenal fat thickness (p = 0.038) and malignant tumors (p = 0.002) were associated with estimated blood loss. Perirenal fat thickness, tumor size, and malignant tumors are valid predictors of the surgical outcomes of transperitoneal laparoscopic adrenalectomy. As only perirenal fat thickness is associated with both surgical outcomes except for malignant tumors, it is a powerful predictor. Transperitoneal laparoscopic adrenalectomy for large malignant adrenal tumors with thick perirenal fat should be performed with caution.

Depletion of dexamethasone in cattle: Food safety study in dairy and beef cattle.

Dexamethasone is approved for cattle in Canada for several conditions, but no withdrawal times are currently provided on the approved labels. Recently, the list of Maximum Residues Limits for Veterinary Drugs in Foods in Canada was amended to include dexamethasone. The objectives of this study were to determine the residue depletion profile of dexamethasone after an extra-label dosage regimen in milk of healthy lactating dairy cattle (n = 18) and in edible tissues of healthy beef cattle (n = 16) and to suggest withdrawal intervals. Dexamethasone was administered intramuscularly at 0.05 mg/kg daily for 3 days. Milk samples were collected prior to treatment and every 12 h up to 96 h post-dose. Muscle, liver, kidney, and peri-renal fat tissues were collected from beef cattle at 3, 7, 11, or 15 days post-dose. Dexamethasone analysis was performed by liquid chromatography/mass spectrophotometry. Dexamethasone residues were detected in milk samples up to 36 h. Muscle and fat had no detectable dexamethasone residues while kidney and liver had detectable residues only on day 3 post-dose. A withdrawal interval of 48 h for milk in Canadian dairy cattle and 7 days for meat in Canadian beef cattle are suggested for the dexamethasone treatment regimen most commonly requested to CgFARAD™.

Распространенность мочекаменной болезни среди женщин старше 45 лет в республике Чувашия.

Introduction. It is believed that Urolithiasis men of working age are most often affected. However, recent studies have shown that the difference between the incidence of this disease among men and women is rapidly decreasing due to the increased incidence of urolithiasis in women. The purpose of the study: to determine the prevalence of urolithiasis among women over 45 years of age as part of screening study in the Republic of Chuvashia. Materials and methods. A population study of 658 women over 45 years of age was conducted on the basis of hospital № 1 in Cheboksary (Republic of Chuvashia) in 2021-2022. All participants underwent ultrasound examination of the urinary system organs to detect urinary stones. The diagnosis was confirmed by CT of the abdominal cavity and retroperitoneal space. Statistical data processing was carried out using the Statistics 10,0 program and Microsoft Excel. Results. Of 658 women, 147 had previously noted urolithiasis in past, 124 of them were associated with this disease (the group with a positive history of urolithiasis), 511 had not previously sought medical help from a urologist for stones of the urinary system (the group with a negative history of urolithiasis). In total, 95 (14.4%) women with calculi in the urinary tract were identified. In the group with a positive history of urolithiasis, stones were detected in 22.4% of cases, with a negative one – in 12.1%. The most frequent localization of concretions in all groups was the lower group of calyx. The size of the concretions varied in the group with a negative history of urolithiasis from 5.70±0.77 mm to 7.50±0.50 mm, in the group with a positive history of urolithiasis – from 5.00±0.56 mm to 21.75±8.24 mm. Conclusion. The present study showed that the true incidence of urolithiasis is 14,4%, which is several times higher than the official figures. To study the true incidence of urolithiasis, it is necessary to conduct large epidemiological studies in the russian population.

Case of successful surgical treatment of the aorto-bifemoral re-occlusion with both lower limbs dry gangrene formation

The paper demonstrates a clinical case of open surgical re-interventional on the abdominal aorta 8 years later after primary aortofemoral bypass through the right and left retroperitoneal accesses. Severe ischemic damage to the tissues of both lower extremities required repeated vascular reconstruction. The tactics of repeated retroperitoneal intervention on the aorta was chosen, while the access could be expanded to thoracophrenolumbotomy. Due to the pronounced cicatricial process in the retroperitoneal space and intraoperative damage to the ureter, the branches of the prosthesis were performed in an atypical manner.

Retroperitoneal Single-Port Robot-Assisted Nephroureterectomy with Bladder Cuff Excision: Initial Experience and Description of the Technique.

With the introduction of the single-port (SP) robot, surgery that was difficult to attempt is becoming possible. Nephroureterectomy (NUx) for upper tract urothelial carcinoma also seems to be able to attempt a retroperitoneal (RP) approach. to investigate the feasibility of SP robotic RP NUx with bladder cuff excision. we sequentially analyzed 20 patients who underwent SP robot NUx from January 2021 to December 2022. all patients were diagnosed with upper tract urothelial carcinoma (UTUC) and were operated upon by a single expert using the da Vinci SP platform (Intuitive Surgical, Sunnyvale, CA, USA) with retroperitoneal approach. A total of 20 patients underwent SP robotic NUx with bladder cuff excision. The mean age of patients was 69.45 ± 8.68 years, and the mean body mass index (BMI) was 25.37 ± 3.00 kg/m2. The mean tumor size was 2.42 ± 1.03 cm on a CT scan, with right-sided tumors in eight patients (40%) and left-sided tumors in 12 patients (60%). The median console time was 106 min and 40 s, and the expected blood loss was 122.50 ± 75.18 mL. Final pathology showed that all of the patients were diagnosed as having urothelial carcinoma; one patient was classified as Ta (5.00%), three patients were classified as T1 (15.00%), seven patients were classified as T2 (35.00%), eight patients were classified as T3 (40.00%), and one patient was classified as T4 (5.00%). None of these 20 patients showed any complications based on the Clavien-Dindo scale. SP robotic NUx using a retroperitoneal approach provides feasible perioperative and postoperative outcomes for UTUC.

Primary Extra Renal Papillary Renal Cell Carcinoma Masquerading as A Metastatic Carcinoma: A Unique Case with Dual Malignancies

A 50-year-old male presented with abdominal pain, pain during defaecation, constipation, bleeding per rectum for 2 months. Colonoscopy showed an ulcero-proliferative growth, that is 2.5 cm from anal verge. Further PET-CT confirmed the growth in the lower rectum with mesorectal fat stranding and an irregular, lobulated, encapsulated solid-cystic mass in right perinephric fat, separated from the kidney (suggestive of metastasis), with intact bilateral kidneys. Biopsy of the rectum revealed an adenocarcinoma and biopsy of right perinephric mass revealed a papillary neoplasm. Following which abdominoperineal resection with perinephric mass excision was performed, due to encapsulation of mass. Histopathological evaluation and further immunohistochemistry performed was positive for vimentin, AMACR, CD10 and negative for other markers to rule out metastasis of either. This led to the diagnosis of synchronous primaries i.e., Extra-renal papillary renal cell carcinoma and adenocarcinoma of rectum.

Variations of azygos vein: a cadaveric study with clinical relevance.

The azygos vein can be formed as a single root, two roots, and three roots, namely lateral, intermediate and the medial roots respectively. The hemiazygos vein and the accessory hemiazygos vein are the tributaries of azygos vein rather than its left side equivalents. Its variations, especially in young persons without any relevant risk factors, may result in thromboembolic illness. This study aimed to describe the morphological and morphometric variations of azygos system of veins. The present study was conducted on thirty formalin fixed adult human cadavers by dissecting azygos vein from formation to termination and variations were noted. The azygos vein was formed by a single root in 56.7%, by two roots: the lateral root and intermediate root in 36.7% cases and by the lateral root and medial root in 6.6%. The vertebral level of termination of azygos vein was seen at the level of T4 vertebrae in 70% cases, at the level of T3 vertebrae in 20% of cases and at the level of T5 vertebrae in 10% cases. The course of azygos vein was varying in 13.3%. These morphological variations can be useful while performing mediastinal surgery, mediastinoscopy, surgery of the deformations of the vertebral column, neurovascular surgeries of the retroperitoneal organs, disc herniation and fracture of thoracic vertebrae.

MiR-383-5p Regulates Preadipocyte Proliferation and Differentiation by Targeting RAD51AP1.

Obesity has become a major health problem worldwide, and increasing evidence supports the importance of microRNAs (miRNAs) in its pathogenesis. Recently, we found that miR-383-5p_1 is highly expressed in the perirenal fat of high-fat-fed rabbits, but it is not yet known whether miR-383-5p is involved in lipid metabolism. Here, we used transcriptome sequencing technology to screen 1642 known differentially expressed genes between miR-383-5p mimic groups and miR-383-5p negative control groups. Gene Ontology Resource (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were enriched in the pathway related to lipid metabolism, and glycine biosynthesis, the NOD receptor signal pathway and nonalcoholic fatty liver were significantly enriched. Afterwards, our research results indicated that miR-383-5p can promote the proliferation and differentiation of rabbit preadipocytes, and there is a direct targeting relationship with RAD51AP1. Mechanistically, miR-383-5p directly interacts with the lipid metabolism and participates in adipogenesis and lipid accumulation by targeting RAD51AP1. In conclusion, our data highlight a physiological role for miRNA in lipid metabolism and suggest the miR-383-5p/RAD51AP1 axis may represent a potential mechanism for controlling lipid accumulation in obesity.

It is easy and effective to locate adrenal gland during retroperitoneal laparoscopic left adrenalectomy by the landmark of left PFSV

To evaluate the feasibility and clinical significance of the left perinephric fat sac vein (PFSV) as an anatomical landmark in locating left adrenal gland (LAD) during retroperitoneal laparoscopic left adrenalectomy (RLLA). In this study, a total of 36 patients who underwent RLLA were enrolled from February 2019 and March 2021. By following a vein vessel on the internal surface of perinephric fat sac (PFS), known as PFSV, LAD was searched finally along the upper edge of this vein. The demographic and clinical characteristics of these patients were acquired, including tumor features and perioperative outcomes (operating time, estimated blood loss, complications). The operations were successfully completed in all the 36 patients without conversion to open surgery. In addition, the LAD was successfully found along the upper edge of PFSV in 34 patients. For all operations, the mean operative time was 75 min (range 60–95) and the estimated blood loss was 20 ml (range 10–50). The median oral intake was 20.7 h (range 6–39). The median hospital stay was 6.3 days (range 4–9), and the median follow-up was 12.3 months (range 9–17). Moreover, no intraoperative complications were observed and no residual tumors were detected after 9 to 15 months follow-up. It may be a safe and efficient procedure to use PFSV as a landmark for searching LAD during RLLA, especially for beginners. However, more studies with larger sample size are need to be conducted to further evaluate the outcomes of this method and the significance of PFSV in searching LAD during RLLA.

Differential depot-specific parameters of adipose tissue cellularity and thermogenesis in preobese congenic LA/Ntul//-cp rats

To determine the effects of adipose tissue development during early normal postweaning growth, groups of lean and obese LA/N//tul-cp rats were subjected to measures of caloric intake, linear growth and of adipose tissue mass, cell lipid content, and adipocyte number in principle adipose tissue depots at 6 weeks of age, prior to the expression of significant adiposity. Live body weights and daily caloric intake of obese &gt; lean by 6 weeks of age, but parameters of linear growth were similar in both phenotypes. Resting metabolic rate (RMR) and the thermic response to norepinephrine (NE, 200 µg/KG BW, s.c.) of lean &gt;&gt; obese rats. Adipose tissue mass and combined fat pad mass:body weight ratio of Dorsal Subcutaneous (DOR), Retroperitoneal (RP), Gonadal (GON), and Interscapular brown adipose tissue (IBAT) depots were greater in the obese than lean phenotype, with the greatest magnitude of increase in the DOR subcutaneous depot. Adipocyte number was modestly greater in DOR subcutaneous depot, while adipocyte lipid content was greater in the RP and GON depots of obese but not lean rats. The IBAT mass and proportion of IBAT:body weight of obese &gt;&gt; lean. These results are consistent with the differential onset of adipose tissue depot growth initially occurs via hyperplasia in the dorsal subcutaneous depot and via hypertrophy in the RP and GON abdominal depots, while lean tissue development was of similar magnitude in both phenotypes at this age.

Dose comparison of robustly optimized intensity modulated proton therapy (IMPT) vs IMRT and VMAT photon plans for testicular seminoma

Background Patients with stage II seminoma have traditionally been treated with photons to the retroperitoneal and iliac space, which leads to a substantial dose bath to abdominal and pelvic organs at risk (OAR). As these patients are young and with excellent prognosis, reducing dose to OAR and thereby the risk of secondary cancer is of utmost importance. We compared IMPT to opposing IMRT fields and VMAT, assessing dose to OAR and both overall and organ-specific secondary cancer risk. Material and methods A comparative treatment planning study was conducted on planning CT-scans from ten patients with stage II seminoma, treated with photons to a ‘dog-leg’ field with doses ranging from 20 to 25 Gy and a 10 Gy sequential boost to the metastatic lymph node(s). Photon plans were either 3–4 field IMRT (Eclipse) or 1–2 arc VMAT (Pinnacle). Proton plans used robust (5 mm; 3.5%) IMPT (Eclipse), multi field optimization with 3 posterior fields supplemented by 2 anterior fields at the level of the iliac vessels. Thirty plans were generated. Mean doses to OARs were compared for IMRT vs IMPT and VMAT vs IMPT. The risk of secondary cancer was calculated according to the model described by Schneider, using excess absolute risk (EAR, per 10,000 persons per year) for body outline, stomach, duodenum, pancreas, bowel, bladder and spinal cord. Results Mean doses to all OARs were significantly lower with IMPT except similar kidney (IMRT) and spinal cord (VMAT) doses. The relative EAR for body outline was 0.59 for IMPT/IMRT (p < .05) and 0.33 for IMPT/VMAT (p < .05). Organ specific secondary cancer risk was also lower for IMPT except for pancreas and duodenum. Conclusion Proton therapy reduced radiation dose to OAR compared to both IMRT and VMAT plans, and potentially reduce the risk of secondary cancer both overall and for most OAR.

Quantitative analysis of the structure of the portal vein of the liver and splenic vein in people with different somatotypes in portal hypertension

BACKGROUND: HeathCarter somatotyping using bioimpedance analysis is one of the most common methods of somatotyping because of its non-invasiveness, portability, comparative reliability of the data, and ease of use. Knowledge of the relationship between portal hypertension and somatotype may lead to the development of effective approaches to the diagnosis, treatment, and prevention of this disease.&#x0D; AIM: To examine the frequency of various somatotypes in people with portal hypertension.&#x0D; MATERIALS AND METHODS: The study included 46 patients with cirrhosis of the liver who were treated at the University Clinical Hospital N 2 Sechenov University. The calculation of endo- (ENDO) and mesomorphy (MESO) scores, assessment of the somatotype by HeathCarter, and data visualization on the somatogram were carried out using the ABC-01 MEDASS software (STC MEDASS, Russia). Portal hypertension was diagnosed by ultrasonography of the abdominal cavity and retroperitoneal space.&#x0D; RESULTS: The diameter of the splenic vein was 7 mm in 17/18 men and 23/28 women. The diameter of the portal vein was 13 mm in 8/18 men and 12/28 women. The mesoendomorphic somatotype was the most common among women and endomesomorphic among men. More than half (n=9; 52.9%) of men had splenic vein diameter large than normal and the endomesomorphic somatotype, whereas the predominant part of women (n=18; 78.3%) had the mesoendomorphic somatotype. Similar results were obtained in patients with portal vein diameter larger than normal, and the endomesomorphic somatotype prevailed among men (n=5; 62.5%) and mesoendomorphic among women (n=10; 83.3%).&#x0D; CONCLUSIONS: The frequency of portal hypertension in patients with different somatotypes varied. It was higher in patients with a pronounced endomorphic component than in those with other somatotypes. In general, our results underline the complexity of the association of portal hypertension with somatotypes and indicate the need for a deeper analysis of this problem and further research. Future studies should include larger numbers of both healthy individuals and patients with chronic liver disease, different age groups, and a broader set of parameters for analysis. Understanding the relationship between portal hypertension and somatotypes can help develop more effective strategies for the prevention and treatment of this syndrome.

Adenocarcinoma of the Jejunum: A Case Report and Literature Review

Abstract Small intestine cancers account for 1-3% of all gastrointestinal tumors, with only 11-25% of these tumors located in the jejunum. We report the case of a woman who has been experiencing abdominal pain for the last six months, accompanied by nausea, vomiting and appearance of dark-colored stools, who has lost 20 kg in weight during the last few months. Laboratory findings indicated anemia and no significant changes were identified in the abdominal ultrasound. By endoscopic examination of the stomach and duodenum and by colonoscopy, no infiltrations were found. Serum markers were elevated and CT scan of the abdomen showed thickening of a part of the jejunum wall with swollen lymph nodes in the mesentery, along the inferior vena cava and abdominal aorta, in the retroperitoneal space. By opening the abdominal cavity, we observed an infiltration in the initial part of the jejunum with an infiltration of the entire wall. Resection of the jejunum with related mesenthery, vessels and lymph nodes therein was performed. Histopathology revealed an invasive adenocarcinoma of the small intestine, with an invasion of all layers of the wall and mesentery. Adjuvant FOLFOX chemotherapy was introduced, 6 cycles in total, and following each cycle, tumor markers have been constantly decreasing. No relapse has been identified after nine months. Due to often deep position in the small intestine, atypical symptomatology and lack of screening, an early diagnosis is difficult. Surgical resection of the affected small intestine followed by an additional chemotherapy is the optimal treatment strategy.

Retroperitoneoscopy of the presacral space in horses: Surgical access and anatomy.

Surgical approaches to the equine rectum and perirectal area are described in the literature. However, surgeries in this region can be challenging. To describe the surgical anatomy of the presacral space and to evaluate its access using a retroperitoneoscopic approach. Ex vivo experiment. Preliminary dissections were performed in two cadavers to define the boundaries of the presacral space and to determine portal locations for the surgical approach. After that, nine cadavers were used for experimental presacral retroperitoneoscopic procedure in a standing position. Following retroperitoneoscopy, cadavers were dissected to confirm the anatomical structures observed during the endoscopic procedures, to control the location of each portal and to record iatrogenic trauma. The presacral space was bordered by the vertebral column from the ventral aspect of lumbosacral promontorium to the first coccygeal vertebra dorsally and by the presacral fascia and peritoneum ventrally. Lateral limits were composed of the sacrosciatic ligament and transversalis fascia. Cranial and caudal borders were composed of the peritoneum and coccygeal and levator ani muscles respectively. Retroperitoneoscopic portals were placed between the external anal sphincter and semimembranosus muscles and between the base of the tail and the external anal sphincter muscle through the anococcygeal fascia to enter the space by its caudal border. The retroperitoneal space was reached in all cases and the dorsal and lateral aspects of the rectum were visualised after creation of a working space. Use of cadaver specimens do not permit to evaluate the tolerance in living animals and the surgical complications such as rectal damage, haemorrhage and infection. This study provides an anatomical description and surgical access of the presacral space with a minimal invasive approach. Retroperitoneoscopy allows access to the rectum and the dorsal aspect of the pelvis.

PE058 - Two-dimensional shear wave elastography: an effective tool in predicting adherent perinephric fat in robot-assisted partial nephrectomy

PE058 - Two-dimensional shear wave elastography: an effective tool in predicting adherent perinephric fat in robot-assisted partial nephrectomy

Primary Retroperitoneal Masses: A Pictorial Essay

AbstractPrimary retroperitoneal masses include a diverse and uncommon group of lesions that arise within the retroperitoneal space, but do not originate from any retroperitoneal organs. The majority of the lesions are malignant and imaging plays a pivotal role in the detection, staging, and preoperative planning. The evaluation of primary retroperitoneal masses is often challenging owing to the unfamiliarity with the common imaging features of various diseases affecting it. This article describes the multidetector computed tomography appearance of some primary retroperitoneal masses.

Gastroenterological manifestations of IgG4 associated disease. Literature review, clinical case

IgG4‑associated disease is a disorder with an unknown etiology and multi‑organ damage caused by a specific inflammatory process, characterized by periductal inflammatory infiltrate mainly by CD4+‑T lymphocytes, IgG4+‑plasma cells, storiform fibrosis, atrophy of acinar tissue, which often results in pancreatic duct stenosis. A great number of target organs are involved in the pathological process, one primary localization of the pathological process without damage to other organs is observed in only 10 — 20% of patients. Mostly affected are middle‑aged and elderly men. The pathological process is stipulated by a pronounced tissue infiltration with lymphocytes and plasma cells, followed by fibrosis development. The clinical picture varies widely, depending on the combination of affected target organs. The long‑term prognosis of the disease has not been sufficiently studied due to the small number of observations, the variety of clinical forms and the variability of treatment approaches. IgG4‑associated lesions have been described for localization in pancreas, biliary tract and gallbladder, liver, esophagus, stomach and intestines, retroperitoneal space, mammary glands and thyroid and prostate glands, salivary and lacrimal glands, kidneys and ureters, lymph nodes, skin and bones. The article presents a review of current literature on gastroenterological lesions in IgG4 associated diseases, as well as a clinical case of a patient with IgG4‑autoimmune pancreatitis type 1, IgG4‑sclerosing cholangitis, autoimmune hepatitis type 1 complicated by 3 type diabetes mellitus. The diagnosis of an IgG4‑associated disease in gastroenterological practice causes some difficulties. However, the timely diagnosis and administration of adequate treatment can significantly improve the quality of life of the patient and prevent the development of complications.

Growth performance, carcass traits, and physicochemical characteristics of Longissimus thoracis of fattening lambs feeding milk thistle (Silybum mariamum) seed powder

This study investigated the effect of supplementing diet with milk thistle seed powder (MTSP) on performance and carcass characteristics of Romanov×Shawl crossbred lambs. Thirty Romanov×Shawl crossbred lambs (six-month-old) were fed diets containing zero (without MTSP), 1 % and 2 % MTSP (wheat bran substitute) in a completely randomized design for 90 days. Lambs fed diet containing 2 % MTSP had higher dry matter intake, final body weight, and daily weight gain (P < 0.05). The best feed conversion ratio was observed for the 2 % MTSP treatment (P < 0.05). The weights of lean meat, warm and cold carcasses, percentage of bone, and ratio of meat to bone were higher in lambs fed with 2 % MTSP diet (P < 0.05) compared with other groups. Eye muscle weight was higher in lambs fed 1 % and 2 % MTSP diets than that of the control group (P < 0.05). The highest perirenal fat was observed in the lambs fed the control diet (P < 0.05). The heart fat weight was decreased linearly with the addition of MTSP diet (P < 0.05). Spleen weight increased linearly by feeding 2 % MTSP compared to other groups. Feeding diet containing MTSP increased meat protein and decreased the concentration of malondialdehyde in Longissimus thoracis (P < 0.05). The results indicated that feeding the diet containing MTSP, especially at the level of 2 %, improved performance, carcass characteristics, and physicochemical parameters of Longissimus thoracis in lambs.