Surgical approach and presence of preoperative pleural effusion impact thoracostomy tube usage in dogs and cats following thoracic surgery for suspected neoplasia

OBJECTIVE

To assess factors associated with increased pleural fluid and air evacuation, longer duration of thoracostomy tube usage, and longer hospitalization in dogs and cats following surgery for thoracic neoplasms.

ANIMALS

62 dogs and 10 cats.

METHODS

Medical records were reviewed for dogs and cats undergoing thoracic surgeries between August 1, 2019, and June 30, 2023, for resection of suspected neoplasia in which a thoracostomy tube was placed. Data collected included patient signalment, type of procedure performed, histologic diagnosis of the primary mass removed, volume of fluid and air evacuated from the thoracostomy tube, and time in hospital.

RESULTS

Median sternotomy was associated with increased total fluid evacuation (median, 12.1 mL/kg; IQR, 15.4 mL/kg; P = .012), whereas rib resection was associated with increased total air evacuation (median, 2.1 mL/kg; IQR, 13.6 mL/kg; P = .06). The presence of preoperative pleural effusion was associated with higher total fluid evacuation (20.6 mL/kg; IQR, 32.1 mL/kg; P = .009), longer duration with a thoracostomy tube in place (42.5 hours; IQR, 41.9 hours; P = .027), and longer hospitalization period (61 hours; IQR, 52.8 hours; P = .025). Cats had a thoracostomy tube in place for a longer time compared to dogs (median, 42.6 hours; IQR, 23.5 hours; P = .043).

CLINICAL RELEVANCE

Animals undergoing median sternotomy and rib resection may be expected to have higher fluid and air volumes, respectively, evacuated postoperatively. This often leads to an increased duration of thoracostomy tube usage and a longer period of hospitalization.

Evaluation of the clinical outcome of hypercalcemia of malignancy and concurrent azotemia in dogs with lymphoma

BACKGROUND

Hypercalcemia of malignancy (HM) secondary to lymphoma in dogs has the potential to cause renal injury.

HYPOTHESIS/OBJECTIVES

Characterize outcomes related to acute kidney injury (AKI) secondary to HM. We hypothesized that dogs do suffer AKI regardless of HM severity at the time of lymphoma diagnosis or relapse.

ANIMALS

Retrospective study. Twenty-nine dogs with lymphoma, HM, and azotemia (International Renal Interest Society [IRIS] grade II or higher AKI) that underwent chemotherapy were identified at 2 veterinary institutions.

METHODS

Logistic regression and descriptive statistical analysis were performed to evaluate data for potential prognostic factors.

RESULTS

After initiating treatment, resolution of hypercalcemia and azotemia occurred in 100% (29/29) and 79.3% (23/29) of dogs, respectively. Resolution of azotemia was influenced by serum creatinine concentration (odds ratio [OR], 0.148; Confidence interval [CI], 0.03-0.734; P = .02) and total hypercalcemia (OR, 0.36; CI, 0.14-0.93; P = .04) at diagnosis, whereas blood urea nitrogen concentration, IRIS grade, sex, and whether or not dogs were hospitalized were not significant factors. At data analysis, 13.8% (4/29) of dogs were alive or lost to follow-up. Of those dead, 4 dogs (15%) had renal disease at the time of death, 2/4 having concurrent lymphoma progression.

CONCLUSIONS AND CLINICAL IMPORTANCE

Although AKI may be of clinical concern in dogs with HM secondary to lymphoma at diagnosis, death secondary to renal impairment appears to be infrequent.

Surgical and oncologic outcomes in dogs with malignant peripheral nerve sheath tumours arising from the brachial or lumbosacral plexus

Malignant peripheral nerve sheath tumours (MPNST) of a plexus nerve or nerve root cause significant morbidity and present a treatment challenge. The surgical approach can be complex and information is lacking on outcomes. The objective of this study was to describe surgical complication rates and oncologic outcomes for canine MPNST of the brachial or lumbosacral plexus. Dogs treated for a naïve MPNST with amputation/hemipelvectomy with or without a laminectomy were retrospectively analysed. Oncologic outcomes were disease free interval (DFI), overall survival (OS), and 1- and 2-year survival rates. Thirty dogs were included. The surgery performed was amputation alone in 17 cases (57%), and amputation/hemipelvectomy with laminectomy in 13 cases (43%). Four dogs (13%) had an intraoperative complication, while 11 dogs (37%) had postoperative complications. Histologic margins were reported as R0 in 12 dogs (40%), R1 in 12 dogs (40%), and R2 in five dogs (17%). No association was found between histologic grade and margin nor extent of surgical approach and margin. Thirteen dogs (46%) had recurrence. The median DFI was 511 days (95% CI: 140-882 days). The median disease specific OST was 570 days (95% CI: 467-673 days) with 1- and 2-year survival rates of 82% and 22% respectively. No variables were significantly associated with recurrence, DFI, or disease specific OST. These data show surgical treatment of plexus MPNST was associated with a high intra- and postoperative complication rate but relatively good disease outcomes. This information can guide clinicians in surgical risk management and owner communication regarding realistic outcomes and complications.

Fluorescence-guided surgical system using holographic display: from phantom studies to canine patients

Significance

Holographic display technology is a promising area of research that can lead to significant advancements in cancer surgery. We present the benefits of combining bioinspired multispectral imaging technology with holographic goggles for fluorescence-guided cancer surgery. Through a series of experiments with 43D-printed phantoms, small animal models of cancer, and surgeries on canine patients with head and neck cancer, we showcase the advantages of this holistic approach.

Aim

The aim of our study is to demonstrate the feasibility and potential benefits of utilizing holographic display for fluorescence-guided surgery through a series of experiments involving 3D-printed phantoms and canine patients with head and neck cancer.

Approach

We explore the integration of a bioinspired camera with a mixed reality headset to project fluorescent images as holograms onto a see-through display, and we demonstrate the potential benefits of this technology through benchtop and in vivo animal studies.

Results

Our complete imaging and holographic display system showcased improved delineation of fluorescent targets in phantoms compared with the 2D monitor display approach and easy integration into the veterinarian surgical workflow.

Conclusions

Based on our findings, it is evident that our comprehensive approach, which combines a bioinspired multispectral imaging sensor with holographic goggles, holds promise in enhancing the presentation of fluorescent information to surgeons during intraoperative scenarios while minimizing disruptions.

Post-operative complications following apocrine gland anal sac adenocarcinoma resection in dogs

Describe the complications associated with surgical resection of primary apocrine gland anal sac adenocarcinoma (AGASACA) tumours study design multi-institutional retrospective cross-sectional cohort study Animals Client owned dogs with spontaneous disease using the Clavien-Dindo classification system, post-operative events were assigned and described. Logistic regression analysis was used to analyse for risk factors for a significant association with complications. One hundred sixty-one dogs were included in the analysis. The post-operative sequelae, complication, and failure to cure rates specific to the anal sac site was 14%, 17% and 1%, respectively. The majority (68%) of complications were grade II or higher, therefore requiring some form of intervention. Intra-operative complications were identified in 11 cases (7%) with anorectal wall perforation being most common. An intra-operative complication was significantly associated with post-operative complications (p < 0.001; OR 7.4) while anorectal wall perforation was the only significant risk factor on regression analysis (p < 0.001; OR 19). Surgical site infection was identified in 20 of 161 (12%) of cases. Local recurrence (LR) occurred in 18% of cases at a median of 374 days (95% CI: 318-430). The only risk factor significantly associated with LR was the presence of vascular or lymphatic invasion (p = 0.008; OR 3). Post-operative complications were relatively infrequent but the risk was significantly increased when there was an intraoperative complication during resection of a primary AGASACA tumour. This study provides information for the clinician regarding risk factors for post-operative complications.

Assessment of the cutaneous trunci reflex in neurologically healthy cats

OBJECTIVES

The aim of this study was to perform the cutaneous trunci reflex (CTR) in neurologically normal cats using two different instruments and determine how body condition score (BCS), body circumference, age, sex and instrument type may affect this reflex.

METHODS

Sixty-five cats without evidence of neurologic disease were prospectively enrolled. Cats were randomly assigned to have the reflex tested first using a pair of hemostatic forceps or the integrated Babinski tip of an MDF Babinski Buck Reflex Hammer. After 30 mins, the reflex was retested using the other instrument. Data collected included the reflex presence, reflex caudal border, reflex intensity (weak, moderate, strong) and reflex symmetry (unilateral or bilateral). The influence of BCS, body circumference, age and sex on these variables was statistically evaluated along with effect of the instrument used.

RESULTS

The CTR was elicited bilaterally in 52 (80%) cats and unilaterally in 64 (98%) cats. In two cats, the CTR was only able to be elicited using the Buck Reflex Hammer, while in four cats, the CTR was only able to be elicited using hemostatic forceps. Body circumference, BCS, age and sex had no effect on the presence, caudal border, intensity or symmetry of the CTR, regardless of the instrument used. No difference in the bilateral presence of the CTR was noted based on the instrument used first (P = 0.53). When assessing the influence of the instrument on reflex presence, caudal border, intensity and symmetry, the hemostatic forceps elicited the reflex further caudally (P = 0.02) and usually bilaterally (P = 0.02).

CONCLUSIONS AND RELEVANCE

The CTR could be elicited in the majority of cats with both instruments. However, hemostatic forceps elicited a reflex more caudally and bilaterally symmetrical than the Buck Reflex Hammer.

Impact of microwave ablation treatment on the biomechanical properties of the distal radius in the dog: A cadaveric study

OBJECTIVE

To determine whether microwave ablation (MWA) modifies the biomechanical properties of the normal distal radius in the dog to better estimate the clinical impact of MWA as a tool for the treatment of neoplastic bone lesions.

STUDY DESIGN

Biomechanical experimental study.

SAMPLE POPULATION

Sixteen pairs of dog forelimbs from 16 canine cadavers.

METHODS

From each pair of forelimbs, one radius was randomly assigned to an MWA group, and the other radius was randomly assigned to a control group. Bone tunnels were created in each distal radial epiphysis for a length of 6 cm toward the middiaphysis. In the MWA group, the ablation probe was inserted into the bone tunnel for a series of three ablation treatments. Specimens were then tested in three-point bending to acute failure with the middle point located 3 cm from the distal articular surface (middle of the ablated zone). Load and displacement were continuously recorded to determine maximum displacement and peak load before failure. Data were analyzed with noninferiority tests.

RESULTS

The mean peak loads for the control group and MWA group were 1641.9 N and 1590.9 N, respectively. Microwave ablation-treated radii were not biomechanically inferior to control radii (P < .0001).

CONCLUSION

Microwave ablation of normal cadaveric dog distal radii did not affect the maximum displacement and peak load before failure.

CLINICAL SIGNIFICANCE

Microwave ablation does not affect biomechanical bending properties of the distal radius in the dog. Future studies, both cadaveric and in vivo, are required to evaluate the impact of MWA on neoplastic bone.

Definitive-intent intensity-modulated radiation therapy for treatment of canine prostatic carcinoma: A multi-institutional retrospective study

No standard of care is currently recognized for treatment of canine prostatic carcinoma (PC). This retrospective study assesses outcome following definitive-intent, intensity-modulated radiation therapy (RT) in dogs with PC. Medical records review was performed, including 18 patients from four institutions undergoing definitive-intent intensity-modulated radiotherapy to treat PC. Diagnosis was incidental in 7/18 (39%) patients. Five dogs (28%) had evidence of metastasis to loco-regional lymph nodes at diagnosis. Seventeen patients received concurrent non-steroidal anti-inflammatory drugs; 15/18 (83%) patients received maximally-tolerated dose (MTD) chemotherapy, with variable drugs and protocols employed. Total prescribed radiation dose ranged from 48 to 54 Gy (median 50 Gy) delivered as daily doses of 2.5-2.8 Gy. One patient was euthanized prior to completing radiotherapy. Acute toxicity was observed in nine patients; Grade 1-2 diarrhoea was the most common toxicity observed. Suspected late toxicity (urethral stricture, ureteral stricture and hindlimb oedema) was observed in three patients. Median event-free survival (EFS) following RT was 220 days, and median overall survival was 563 days. Local progression occurred in seven patients at a median of 241 days. Median overall survival was significantly longer in incidentally diagnosed dogs (581 vs 220 days in symptomatic dogs, P = .042). EFS was significantly longer in patients treated with MTD chemotherapy (241 vs 25 days, P < .001), and significantly shorter in patients presenting with evidence of metastatic disease (109 days) vs those without (388 days, P = .008). These findings suggest that definitive-intent radiotherapy is a valuable treatment option for local control of canine PC with moderate risk of toxicity.

Computed tomography-guided additive manufacturing of Personalized Absorbable Gastrointestinal Stents for intestinal fistulae and perforations

Small bowel perforations and obstructions are relatively frequent surgical emergencies, are potentially life-threatening, and have multiple etiologies. In general, treatment requires urgent surgical repair or resection and at times can lead to further complications. Stents may be used to help with healing intestinal perforations but use is limited as currently available stents are non-absorbable, are manufactured in a narrow size range, and/or are limited to usage in locations that are accessible for endoscopic removal post-healing. The use of 3D-printed bioresorbable polymeric stents will provide patients with a stent that can prevent leakage, is tailored specifically to their geometry, and will be usable within the small bowel, which is not amenable to endoscopic stent placement. This work focused on the rapid manufacturing of gastrointestinal stents composed of a polycaprolactone-polydioxanone (PCL-PDO) composite. Dynamic Mechanical Analysis (DMA) tests were conducted to separately analyze the effects of composition, the filament formation process, and physiological temperature on the PCL-PDO material properties. The proposed stent design was then modeled using computer-aided design, and Finite Element Analysis (FEA) was used to simulate the effects of physiologically relevant forces on stent integrity. The presence of hydrolysable ester bonds was confirmed using FT-IR spectroscopy. In vitro studies were used to evaluate the biocompatibility of the polymer composite. Further analyses were conducted through stent placement in ex vivo pig intestines. PCL-PDO stents were then 3D-printed and placed in vivo in a pig model.

Diagnostic Utility of Abdominal Ultrasonography for Routine Staging at Diagnosis of Skeletal OSA in Dogs

The rate of soft tissue metastases and the importance of abdominal ultrasonography in initial staging of canine skeletal osteosarcoma (OSA) are not known. The purpose of this study was to determine whether abdominal ultrasonography should be performed routinely at initial diagnosis of skeletal OSA or if certain abnormal physical examination or diagnostic findings would provide greater indication to perform ultrasonography. Eighty dogs with OSA that had an abdominal ultrasonogram performed at diagnosis were included. Abnormal findings were present in 36 of 80 dogs. Twenty-three abnormalities were evaluated with either fine-needle aspirate or biopsy and 19 were benign. None of the ultrasonograms revealed abdominal OSA metastases; however, 4 of the 80 ultrasonograms (5%) revealed another primary neoplasia. Further, 2 of the 9 cases that received an ultrasonogram due to a palpable abdominal mass were diagnosed with another primary neoplasia compared with only 1 of the 49 cases that received an ultrasonogram for routine staging. Abdominal ultrasonography as a part of staging is unlikely to reveal metastases from OSA and may not be a useful routine staging tool; however, in certain populations of dogs, such as those with palpable abdominal masses, abdominal ultrasonography may reveal abnormalities that may influence treatment decisions.