One stage functional end-to-end stapled intestinal anastomosis and resection performed by nonexpert surgeons for the treatment of small intestinal obstruction in 30 dogs

Objectives: To describe stapled 1‐stage functional end‐to‐end intestinal anastomosis for treatment of small intestinal obstruction in dogs and evaluate outcome when the technique is performed by nonexpert surgeons after limited training in the technique. Study Design: Case series. Animals: Dogs (n=30) with intestinal lesions requiring an enterectomy. Methods: Stapled 1‐stage functional end‐to‐end anastomosis and resection using a GIA‐60 and a TA‐55 stapling devices were performed under supervision of senior residents and faculty surgeons by junior surgeons previously trained in the technique on pigs. Procedure duration and technical problems were recorded. Short‐term results were collected during hospitalization and at suture removal. Long‐term outcome was established by clinical and ultrasonographic examinations at least 2 months after surgery and from written questionnaires, completed by owners. Results: Mean±SD procedure duration was 15±12 minutes. Postoperative recovery was uneventful in 25 dogs. One dog had anastomotic leakage, 1 had a localized abscess at the transverse staple line, and 3 dogs developed an incisional abdominal wall abscess. No long‐term complications occurred (follow‐up, 2–32 months). Conclusion: Stapled 1‐stage functional end‐to‐end anastomosis and resection is a fast and safe procedure in the hand of nonexpert but trained surgeons.     

Intestinal surgery in small animals: historical foundations,current thinking,and future horizons

Intestinal wounds require precise closure after intestinal biopsy, enterotomy, or enterectomy in small animals. Preexisting factors such as intra‐abdominal sepsis and hypoalbuminemia as well as poor surgical technique increase the risk of intestinal dehiscence, with considerable negative impact on patient morbidity and mortality. Live dog studies have demonstrated the dangers of mucosal eversion especially in the septic abdomen. Approximating patterns preserve luminal diameter, heal optimally, and have equal bursting strength compared with inverting patterns after 24 hours. Simple interrupted and simple continuous suture patterns and disposable skin staples are established alternatives for manual wound closure. Knotless quilled suture currently used in laparoscopic gastropexy techniques shows bursting strength equal to monofilament sutures in dog cadaveric intestine. Dehiscence rates with hand sewn vs titanium automated stapling anastomosis are similar in uncomplicated cases; however, auto stapling devices may be the preferred method of anastomosis when preexisting abdominal sepsis is present and when patient size allows it. Regardless of the technique, current standard of care involves leak testing and omental wrapping, followed by early postoperative feeding. The past decade has ushered in an exciting new era of laparoscopic assisted techniques that have the potential to reduce postoperative pain and patient morbidity. An understanding of these applications will establish the future of minimally invasive small animal intestinal surgery for veterinary specialists. In summary, surgeons have a variety of methods at their disposal for optimal clinical outcome in small animal intestinal surgery.     

Hand‐assisted laparoscopic adhesiolysis of extensive small intestinal adhesions in a mare after breeding injury

In this article we report the course of disease in a mare following severe vaginal injury during natural cover. Although the genital injury healed completely, the mare developed extensive intra‐abdominal intestinal adhesions causing complete small intestinal obstruction 2 years after the incident. The adhesion was not accessible during initial emergency laparotomy and a standing, hand‐assisted laparoscopic adhesiolysis and jejuno‐jejunal end‐to‐end anastomosis were subsequently performed. The mare was subjected to euthanasia 10 weeks after surgery due to recurrence of abdominal pain. The pertaining literature is discussed in regards to this case.     

Gastric and intestinal surgery.

Gastric surgery is commonly performed to remove foreign bodies and correct gastric dilatation-volvulus and is less commonly performed to treat gastric ulceration or erosion, neoplasia, and benign gastric outflow obstruction. Intestinal surgery, although commonly performed by veterinarians, should never be considered routine. The most common procedures of the small intestinal tract performed in dogs and cats include enterotomy and resection/anastomosis. Surgery of the large intestine is indicated for lesions causing obstruction, perforations, colonic inertia, or chronic inflammation.     

Survival rates for horses undergoing stapled small intestinal anastomosis: 84 cases (1988-1997)

OBJECTIVE: To determine whether location and type of small intestinal anastomosis and other variables were associated with short- and long-term survival rates in horses undergoing stapled small intestinal anastomosis. DESIGN: Retrospective study. ANIMALS: 84 horses that underwent small intestinal anastomosis. PROCEDURE: Medical records from 1988 to 1997 were examined for horses that underwent stapled small intestinal anastomosis. Horses were allotted into 4 groups: jejunojejunostomy (n = 27), jejunoileostomy (11), jejunoileocecostomy with small intestinal resection (20), and jejunoileocecostomy without small intestinal resection (26). Survival rates and other variables were determined. RESULTS: Horses that underwent jejunoileocecostomy without resection had a significantly higher survival rate at all intervals than did horses in the other 3 groups. At 180 and 365 days after surgery, horses that underwent jejunojejunostomy had a significantly lower survival rate than those that underwent jejunoileocecostomy with intestinal resection. Horses that underwent jejunoileocecostomy with intestinal resection had a significantly higher survival rate at 1 year, compared with the combined jejunojejunostomy and jejunoileostomy groups. Preoperative heart rate was inversely associated with survival rate. Overall survival rates at discharge and 1 year were 81 and 56%, respectively. For horses that underwent small intestinal resection, survival rates at discharge and 1 year were 65 and 47%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Horses that underwent anastomosis of the small intestine to the cecum without resection had the highest survival rate, compared with horses that required intestinal resection. In some instances, resection and anastomosis involving the cecum had better prognosis than resections involving 2 segments of the small intestine.     

Extensive small bowel resection in dogs and cats: 20 cases (1998-2004)

OBJECTIVE: To determine outcome in dogs and cats that underwent extensive (ie, > 50%) resection of the small intestine and identify factors associated with outcome. DESIGN: Retrospective case series. ANIMALS: 13 dogs and 7 cats. PROCEDURE: Medical records were reviewed, and follow-up information was obtained. RESULTS: In all 7 cats and in 8 of the 13 dogs, extensive intestinal resection was performed because of a foreign body. Mean+/-SD estimated percentage of intestine that was removed was 68+/-14% (range, 50% to 90%). Two dogs were euthanized 3 days after surgery because of dehiscence of the surgical site and development of septic peritonitis; 1 dog died of acute respiratory distress syndrome 5 days after surgery. The remaining 10 dogs and 7 cats were discharged from the hospital, and follow-up information was available for 15 of the 17. Median survival time was 828 days, and 12 of the 15 animals for which long-term follow-up information was available had good outcomes. However, none of the factors examined, including percentage of intestine resected, were significantly associated with outcome. CONCLUSIONS AND CLINICAL RELEVANCE: Most dogs and cats that underwent extensive resection of the small intestine had a good outcome. The amount of intestine resected was not associated with outcome. These data may be useful in providing prognostic information in cases of extensive small intestinal resection.     

Effects of glutamine supplementation of an amino acid-based purified diet on intestinal mucosal integrity in cats with methotrexate-induced enteritis.

OBJECTIVE: To determine effects of glutamine-supplemented and glutamine-free amino acid-based purified diets, compared with a dry expanded diet, on intestinal structure and function in a model that used cats with methotrexate-induced enteritis. ANIMALS: 18 adult specific-pathogen-free cats. PROCEDURE: 12 cats were given intragastric feedings of an amino acid-based purified diet supplemented with glutamine (7% [wt:wt]) or an isonitrogenous amount of glycine and alanine; 6 cats consumed a dry expanded diet. After 21 days, cats received methotrexate (MTX; 11 mg/kg of body weight, IV). Intestinal permeability testing was performed immediately before and 66 hours after MTX administration. Celiotomy was performed 72 hours after MTX administration for aseptic removal of mesenteric lymph nodes, collection of full-thickness intestinal biopsy specimens, determination of intestinal cellular proliferation, and collection of aortic and portal venous blood samples for determination of arteriovenous amino acid concentrations across the intestine. RESULTS: Administration of MTX was associated with severe enterotoxicosis manifested as diarrhea (8/12 cats), vomiting (12/12), and positive results for bacterial culture of mesenteric lymph nodes (12/12) in cats receiving the purified diets, independent of glutamine supplementation. Diet did not affect villus tip length and villus surface area in the small intestine or cellular proliferation. Administration of MTX was associated with significantly increased intestinal permeability, which was not attenuated by glutamine supplementation. CONCLUSIONS: Feeding of a glutamine-supplemented amino acid-based purified diet was unable to preserve intestinal function in cats with MTX-induced enteritis. CLINICAL RELEVANCE: Intestinal morphologic alterations correlate poorly with intestinal function as measured by means of bacterial translocation and intestinal permeability.     

Conversion from diagnostic laparoscopy to laparotomy: risk factors and occurrence

Objective: To determine reasons for conversion from diagnostic laparoscopic procedures to celiotomy in dogs and cats. Study Design: Case series. Animals: Dogs (n=54), cats (40). Methods: Medical records (2004–2008) were reviewed for dogs and cats that had diagnostic laparoscopic or laparoscopic‐assisted biopsy. Numbers of conversions to laparotomy were recorded, including cause and type (elective versus emergent), postoperative complications, and short‐term outcome. Specific risk factors for conversion, including signalment, preoperative diagnostics, and surgical findings were assessed; categorical variables were tested by χ² and Fisher's exact tests; continuous variables by Student's t‐test and Wilcoxon's rank‐sum tests; multivariate logistic regression models were created. Results: Twenty animals (21%) had laparoscopic conversion; 13 (65%) were considered elective and 7 (35%) emergent conversions. There was no significant difference between animals requiring and those not requiring conversion for age, weight, sex, body condition score, clinical signs, previous abdominal surgery, or surgeon experience. Significant risk factors for conversion included low total solids (P=.03), presence of a solitary liver tumor (P<.01), and diagnosis of neoplasia (P<.01). Conclusions: A conversion rate of 21% was found in this population of dogs and cats undergoing laparoscopic diagnostic procedures. A preoperative finding of a solitary liver tumor, low total solids, and diagnosis of malignancy were all significant risk factors for conversion.     

Wound Retractor Laparoscopic Port System for Standing Laparoscopic Cryptorchidectomy in the Horse: A Case Report

Cryptorchidectomy is the most commonly performed laparoscopic procedure in horses. However, its use for the extraction of an abdominal testis has disadvantages such as loss of a resected testis from grasp and fragmentation of the specimen because of the excessive tension required for extraction through a thick body wall. The ring wound retractor laparoscopic port system was recently used in human and small animal surgery to perform laparoscopic-assisted procedures and retrieve large specimens from the abdomen. In the present case, the wound retractor was placed as the ventral port in the right flank through a minilaparotomy. Thereafter, the cap with the gas inlet and instrument port was connected. The other two ports were placed dorsally using 10-mm stainless steel cannulas. Grasping forcep was introduced through the ventral port, and the laparoscope and vessel-sealing devices were introduced through the dorsal ports. After the testis was resected, it was retrieved from the abdomen through the retractor without the grasping forceps jaw being released. This is the first case report describing the use of the wound retractor laparoscopic port system for standing cryptorchidectomy in a horse. This system can be a feasible and safe option for flank laparoscopy in horses, and it facilitates specimen retrieval from the abdominal cavity, but further studies should confirm this preliminary report.     

Successful management of jejunojejunal anastomosis dehiscence by extra-abdominal exteriorization and bandaging in a cat with septic peritonitis

Duodenal and jejunal resections were performed in a cat with septic peritonitis due to small intestinal perforations by a linear foreign body. Three days later jejunal resection and anastomosis were repeated due to dehiscence of the anastomosis site. This segment of intestine was exteriorized through the body wall and managed with bandages for 5 days before it was surgically replaced into the abdomen. The cat made a full recovery.     

Use of cecal bypass via side-to-side ileocolic anastomosis without ileal transection for treatment of cecocolic intussusception in three horses

CASE DESCRIPTION: 3 horses were evaluated for signs of colic; cecocolic intussusception was detected. CLINICAL FINDINGS: Abnormalities detected included diminished intestinal sounds, inflammatory leukogram, dehydration, unremarkable fi ndings via rectal palpation, and ultrasonographic evidence of large intestine intussusception. Laparotomy revealed cecocolic intussusception. TREATMENT AND OUTCOME: Cecal bypass via side-to-side ileocolic anastomosis without ileal transection was performed in each horse by use of an intraluminal anastomosis stapler device. Postoperative complications were minimal, and all horses recovered rapidly and were clinically normal at > 12 months after surgery. CLINICAL RELEVANCE: Cecal bypass via side-to-side ileocolic anastomosis without ileal transection seemed to offer 2 potential advantages over traditional surgical techniques for treating this condition. The risk of abdominal contamination was far less than with techniques in which the colotomy is needed to enable resection of the cecum or techniques in which the ileum is transected. Also, it was technically simpler to perform because there was no need to transect the ileum, oversew the ileal stump, perform cecal resection, or close the mesenteric space created by relocating the jejunal stump to the right ventral colon.     

Risk factors for leakage following intestinal anastomosis in dogs and cats: 115 cases (1991-2000)

OBJECTIVE: To identify factors associated with leakage following intestinal anastomosis in dogs and cats. DESIGN: Retrospective study. ANIMALS: 90 dogs and 25 cats. PROCEDURE: Medical records of all dogs and cats that underwent intestinal resection and anastomosis between 1991 and 2000 were reviewed, and information on 27 factors was recorded. RESULTS: Anastomotic leakage was identified in 13 of the 90 dogs but in none of the 25 cats. Preoperative factors significantly associated with development of anastomotic leakage in dogs included preoperative peritonitis, serum albumin concentration, a left shift, and indication for surgery (dogs with intestinal foreign bodies were more likely to have leakage than dogs that underwent surgery for any other cause). Postoperative and case management factors significantly associated with development of leakage included duration of hospitalization, supplemental alimentation, whether the dog ate the day after surgery, blood product administration, and outcome (died vs survived). Discriminant analysis was performed, and dogs with 2 or more of the following factors were predicted to develop anastomotic leakage: preoperative peritonitis, intestinal foreign body, and serum albumin concentration < or = 2.5 g/dL. The model accurately predicted whether leakage would develop in 67 of 80 (84%) dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a variety of factors may be associated with development of intestinal anastomotic leakage in dogs. In particular, dogs with 2 or more of the following risk factors are predicted to be at high risk for developing anastomotic leakage: preoperative peritonitis, intestinal foreign body, and serum albumin concentration < or = 2.5 g/dL.     

Mesenteric rents as a source of small intestinal strangulation in horses: 15 cases (1990-1997)

OBJECTIVE: To describe the clinical findings in horses with small intestinal strangulation through mesenteric rents, and to determine the recurrence and survival rates after surgery. DESIGN: Retrospective study. ANIMALS: 15 horses with small intestinal obstruction via a mesenteric rent. PROCEDURE: Medical records of horses with obstruction of the small intestine via a mesenteric rent between January 1990 and December 1997 were reviewed. The signalment, history, initial physical examination findings, results of abdominocentesis, and clinical laboratory values were recorded. Surgical findings, including location of the mesenteric rent and surgical procedure performed, were recorded. Short- and long-term survival rates were calculated. RESULTS: Most mesenteric rents were located in the mesentery of the small intestine (13 horses). Two horses had multiple mesenteric defects. Seven horses were euthanatized at surgery because of an inability to reduce the entrapped intestine (3 horses), uncontrollable hemorrhage (2), inability to close the rent (1), and the amount of compromised intestine involved (1). Seven horses required intestinal resection and anastomosis. The median length of intestine resected was 2.6 m (range, 0.6 to 4.5 m). The mesenteric rents created during resection were not closed in 2 horses. One of these 2 horses subsequently developed a strangulating obstruction through the open rent. Seven of 15 horses in our study were discharged from the hospital (i.e., short-term survival rate of 47% [7/15]). Long-term follow-up information was available for 5 of the 7 horses (follow-up duration of 5 months to 9 years), of which 2 died as a result of colic, and 1 horse was euthanatized because of severe arthritis (i.e., long-term survival rate of 40% [2/5]). CONCLUSIONS AND CLINICAL RELEVANCE: Inability to reduce the intestinal obstruction, severe hemorrhage from the mesentery, and the length of intestine involved are the main factors that decrease survival rates in horses with small intestinal strangulation caused by mesenteric rents.     

Rectovaginal fistula following colectomy with an end-to-end anastomosis stapler for a colorectal adenocarcinoma

An 11-year-old, female neutered Labrador retriever was presented with a micro-invasive differentiated papillar adenocarcinoma at the colorectal junction. A colorectal end-to-end anastomosis stapler device was used to perform resection and anastomosis using a transanal technique. A rectovaginal fistula was diagnosed two days later. An exploratory laparotomy was conducted and the fistula was identified and closed. Early dehiscence of the colon was also suspected and another colorectal anastomosis was performed using a manual technique. Comparison to a conventional manual technique of intestinal surgery showed that the use of an automatic staple device was quicker and easier. To the authors' knowledge, this is the first report of a rectovaginal fistula occurring after end-to-end anastomosis stapler colorectal resection-anastomosis in the dog. To minimise the risk of this potential complication associated with the limited surgical visibility, adequate tissue retraction and inspection of the anastomosis site are essential.     

Laparoscopic Cholecystectomy for Management of Uncomplicated Gall Bladder Mucocele in Six Dogs

Objectives— To describe a technique for, and outcome after, laparoscopic cholecystectomy (LC) for management of uncomplicated gall bladder mucocele (GBM) in dogs. Study Design— Case series. Animals— Dogs (n=6) with uncomplicated GBM. Methods— Dogs with ultrasonographic evidence of GBM but without imaging or laboratory signs of gall bladder rupture, peritonitis, or extra‐hepatic biliary tract rupture that had LC were included. A 4 portal technique was used. A fan retractor was used to retract the gall bladder to allow dissection around the cystic duct with 5 or 10 mm right‐angle dissecting forceps. The cystic duct was ligated using extracorporeally tied ligatures supplemented sometimes with hemostatic clips. A harmonic scalpel was used to dissect the gall bladder from its fossa. The gall bladder was placed into a specimen retrieval bag and after bile aspiration the bag was withdrawn through the 11 mm portal incision. Results— Five dogs had mild intermittent clinical signs including vomiting, inappetence, and lethargy. All dogs had successful LC without conversion to an open approach. All dogs with clinical signs had improvement or resolution of signs postoperatively. No important perioperative complications occurred and all dogs were alive at a median of 8 months postoperatively (range, 3–14 months). Conclusions— LC can be accomplished safely and effectively in dogs with uncomplicated GBM. Clinical Relevance— A minimally invasive approach for cholecystectomy can be used for the treatment of GBM in dogs.     

Ultrasonographic differentiation between portal venous and parenchymal gas may be important for the prognosis of canine and feline hepatic emphysema: 37 cases

The aim of this retrospective, cross‐sectional, study was to evaluate clinical findings and outcomes for different ultrasonographic patterns of hepatic emphysema in dogs and cats. Dogs and cats with an ultrasonographic diagnosis of hepatic emphysema and a known outcome, from January 2010 to January 2018, were enrolled. The following data were recorded from medical and ultrasonographic records: ultrasonographic patterns of hepatic emphysema (parenchymal, portal venous, biliary), clinical signs, laboratory findings, and outcomes (favorable, poor). A total of 33 dogs and four cats met the inclusion criteria. Among these, 23 cases were classified as hepatic portal venous gas, 10 as parenchymal emphysema, and four as biliary emphysema. Clinical diagnosis categories were as follows: infection/sepsis (9), gastro‐intestinal disease (9), iatrogenic (9), trauma (5), and liver neoplasia (5). An increase in serum liver enzymes was significantly associated with parenchymal emphysema (P = .03). Other clinical and laboratory findings were not associated with the type of hepatic emphysema. Hepatic portal venous gas was mostly transient in patients with ultrasonographic follow‐up. The overall mortality was 40.5%. A significant difference was found between mortality by portal venous gas (21.7%) and mortality by parenchymal emphysema (90%) (P = .003). In conclusion, the ultrasonographic differentiation of hepatic emphysema between hepatic portal venous gas and parenchymal emphysema may be important for the prognosis of hepatic emphysema. The presence of parenchymal emphysema may be a poor prognostic indicator, while hepatic portal venous gas may be more benign. However, ultrasound findings should be carefully evaluated in the context of clinical findings.     

The equine gastrosplenic ligament: Anatomy and clinical considerations

A gelding was referred for colic and inguinal wound evaluation. Abdominal ultrasound showed distended, oedematous and immotile small intestine abaxial to the spleen. An exploratory laparotomy revealed jejunal incarceration through a rent in the gastrosplenic ligament (GSL). The rent in the GSL was opened and surgical correction (resection and anastomosis of nonviable jejunum) performed. The GSL was left open. The horse recovered uneventfully and one year after surgery no further episodes of colic have been observed.     

Laparoscopic Ovariectomy in Dogs: Comparison Between Single Portal and Two-Portal Access

Objective: To compare surgical times and perioperative complication rates of single portal access and 2-portal laparoscopic ovariectomy (LapOVE) in dogs using a bipolar vessel sealer/divider device, and to evaluate the performance of novice laparoscopists for right ovariectomy.
Study Design: Controlled clinical trial.
Animals: Female dogs (n=42).
Methods: Dogs were divided into groups: 1=single portal and 2=2 portal. LapOVE was performed using a 5 mm vessel sealer/divider device and a 10 mm operating laparoscope (Group 1) or a 5 mm laparoscope (Group 2). Dog characteristics (weight, body condition score, ovarian ligament fat score), operative time, and perioperative complication rate were compared between groups. Right ovariectomy duration was evaluated for 2 novice laparoscopists.
Results: No significant difference was found in mean total surgical time between group 1 (21.07 min/s) and group 2 (19.06 min/s). Factors significantly affecting times included body condition scores, ovarian ligament fat score, ovarian bleeding, and surgeon expertize. Minor complications (bleeding from ovaries or after splenic trauma) occurred and were similar in both groups. Bleeding was correlated to body condition score and ovarian ligament fat score. Interindividual differences were found among surgeons for right ovariectomy time.
Conclusions: Single portal access LapOVE using vessel sealer/divider device is feasible, safe, and does not significantly increase total surgical time in comparison with 2-portal approach. Laparoscopic skills may play a role in ability to perform single portal LapOVE.
Clinical Relevance: LapOVE can be performed using single portal access.     

Subtotal Colectomy With Surgical Stapling Instruments Via a Trans-cecal Approach for Treatment of Acquired Megacolon in Cats

Surgical stapling equipment was used to perform an end-to-end colonic anastomosis in 15 cats for the treatment of acquired megacolon. An end-to-end stapling device was passed to the anastomotic site by a trans-cecal approach. Subsequent closure of the cecal incision was accomplished with a thoracoabdominal stapling device. Two cats had hemorrhagic episodes immediately after surgery that required blood transfusions. All 15 cats have had good to excellent health after subtotal colectomy and colocolostomy performed using this stapling technique. Results of this study have demonstrated that "single surgical field" placement of the end-to-end stapling device has the primary advantage of simplicity and a lower chance of contamination compared with (dual field) rectal passage of similar devices. Closure of the cecal access incision is easily performed without reducing the diameter of the large intestinal lumen. The stapling technique provided an efficient and consistent method for anastomosis of the large bowel in cats.     

Thoracoscopic lung lobectomy for treatment of lung tumors in dogs

OBJECTIVE: To report use of thoracoscopic lung lobectomy (TLL) for treatment of lung tumors (LT) in dogs. STUDY DESIGN: Retrospective study. ANIMALS: Nine dogs. METHODS: Dogs that had TLL for tumor removal were included. Using general anesthesia and 1-lung ventilation, TLL was performed using a 30-60 mm endoscopic gastrointestinal anastomosis stapler. If the visual field was obscured, lobe resection was completed via thoracotomy. RESULTS: Metastatic and primary LT were resected by thoracoscopic lobectomy in 9 dogs (6 male, 3 female; mean (+/-SD) weight, 29+/-7 kg; mean age, 10.7+/-1.9 years). Six dogs had a solitary mass and 3 dogs had 2 masses within a single lobe. The left caudal lobe was removed in 3 dogs. In 5 dogs, TLL was used alone whereas conversion to thoracotomy was required in 4 dogs because of poor visibility. There were 7 metastatic LT and 2 primary LT. Mean duration of thoracoscopic surgery was 108.8+/-30.3 minutes compared with 150.75+/-55.4 minutes in dogs requiring conversion to thoracotomy. Mean hospitalization was 3.1+/-1.3 days. CONCLUSION: Provided the visual field is not obscured, TLL can be performed effectively in dogs. CLINICAL RELEVANCE: Dogs with metastatic or primary LTs should be considered for TLL, particularly for small masses positioned away from the hilus in the left caudal lung lobe.