Hemipelvectomy: outcome in 84 dogs and 16 cats. A veterinary society of surgical oncology retrospective study

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.

Surgical Excision of Intramuscular Sarcomas: Description of Three Cases in Dogs

Compartmental excision consists of the complete resection of an anatomic district in which specific structures act as a barrier to local tumour invasion. It is a well-established procedure in human medicine, while only a few reports are available in veterinary medicine. The aim of this study was to describe complete muscle resection in 3 dogs affected by different intramuscular sarcomas. The clinical outcome was also reported. Medical records were searched, including preoperative diagnostic findings, compartmental excision, histologic diagnosis, and outcome. Three dogs fit the inclusion criteria, which had a sarcoma confined to a single muscular belly (semitendinosus, biceps, and splenius capitis muscles). Complete excision of the affected muscle was performed in all cases. One dog showed moderate lameness in the immediate postoperative period, resulting from the dorsal lifting of the scapula due to serratus ventralis tenotomy performed to remove the caudal insertion of the splenius capitis muscle. All the dogs recovered fully within one month, experiencing good clinical function. Histopathology showed complete tumour removal with no neoplastic fascial disruption in all cases. Compartmental excision provides effective local tumour control, representing an alternative to limb amputation or more radical excision if adjuvant radiotherapy is not an option for owners.

Treatment of canine and feline sarcoma using MR-guided focused ultrasound system

PURPOSE

In recent years, veterinary medicine has enhanced its applications beyond traditional approaches, progressively incorporating the Focused Ultrasound (FUS) technology. This study investigated the ability of FUS to precisely ablate naturally occurring canine and feline soft tissue sarcomas (STS).

METHODS

Six dogs and four cats with superficial tumours were enrolled in the study. The tumours were treated with a Magnetic Resonance guided FUS (MRgFUS) robotic system featuring a single element spherically focused transducer of 2.6 MHz. The tumours were then removed by surgery and sent for hematoxylin and eosin (H&E) staining.

RESULTS

The MRgFUS system was capable of inflicting well-defined overlapping lesions in the tumours. The anatomical sites of the treated tumours were the neck, leg, face, back and belly. Coagulative necrosis was evidenced by histopathology assessment in 80% of cases.

CONCLUSION

Therefore, this technology can be a therapeutic solution for veterinary cancer and a model for advancing the knowledge on human STS.

Pelvic Endoprosthesis after Hemipelvectomy Using a 3D-Printed Osteotomy Guide for Infiltrative Osteoma in a Cat

With the development of 3D printing and surgical techniques, various defect reconstruction methods after tumor resection have been applied not only in humans but also in veterinary medicine. This report describes a case of reconstruction after hemipelvectomy for an osteoma in a cat using a 3D-printed pelvic endoprosthesis and micro total hip replacement (mTHR). A 5-year-old spayed female Turkish Angora cat was referred for a 1-month history of constipation and intermittent weight-bearing lameness in the left hindlimb. An osteoma in the pelvis measuring 4.5 × 3 × 5.4 cm was identified based on diagnostic examinations. A left mid-to-caudal partial and right caudal partial hemipelvectomy, and a left femoral head and neck osteotomy, were planned to remove the mass. Reconstruction of the bone defect using 3D-printed metal endoprosthesis and mTHR in the left hindlimb was intended. During right caudal partial hemipelvectomy, right femoral head and neck osteotomy was performed because there was infiltration in the medial wall of the acetabulum. Histopathological examination confirmed the diagnosis of an osteoma. Two weeks post-surgery, surgical debridement and femoral stem removal were performed because of delayed wound healing and sciatic neurapraxia, leading to femoral stem dislocation from the cup. The delayed wound healing and sciatic neurapraxia were appropriately addressed. The cat regained normal weight and defecation 4 weeks post-operatively. Two years post-surgery, the patient recovered with an almost normal gait. Hemipelvectomy with 3D-printed endoprosthesis provides a safe surgical option with favorable outcomes for neoplasms in the pelvis of cats.

Cranial internal hemipelvectomy (iliectomy) with limb sparing for a dog with ilial chondrosarcoma: A case report

Cranial internal hemipelvectomy can be successful for excision of ilial CSA with minimal complications. Iliectomy with adjuvant radiation therapy was well tolerated in a dog with grade II ilial CSA. The dog survived 1,271 days postoperatively and supposedly succumbed to a disease process unrelated to the CSA.

Mid-to-caudal partial hemipelvectomy with limb preservation for ischial tumor in a dog

A 10-year-old spayed female Golden Retriever was referred for hindlimb lameness. A firm mass was palpated over the right caudal pelvis. Computed tomography revealed an osteolytic bone region and an associated periosteal reaction in the ischium, including the acetabulum. The histological diagnosis was sarcoma of unknown origin. A mid-to-caudal partial hemipelvectomy was performed to remove the mass. Femoral head and neck osteotomy was performed to allow hindlimb preservation. Following surgery, the dog regained satisfactory hindlimb use over time and was alive for 821 days with no recurrence or metastatic disease. This report indicates that mid-to-caudal partial hemipelvectomy with femoral head and neck osteotomy is technically feasible and allows for tumor control with preservation of the hindlimb and its function.

Novel radical pelvectomy technique to treat chondrosarcoma in a large-breed dog

Surgical management of chondrosarcoma with hemipelvectomy is well described, but there have been no reports on extensive excision involving bilateral pubis and unilateral ischium. This report describes a novel pelvectomy technique for the treatment of chondrosarcoma in a large-breed dog. A 12-year-old Labrador Retriever presented for tenesmus due to a large, intra-pelvic mass which was confirmed on computed tomography (CT). Surgery involved removal of the entire left ischium and both pubic bones with preservation of both hind limbs. Histopathology confirmed the diagnosis of a high-grade chondrosarcoma with tumour-free margins of less than 3 mm. The dog recovered well following surgery and regained ambulation within 9 days. Four months postoperatively, the dog had no ongoing pain or tenesmus and only a mild gait abnormality in the left hind limb. Pelvectomy involving the entire pubis and unilateral ischium was well tolerated in a large-breed dog. This technique may offer a novel surgical option to treat neoplasia previously considered too extensive for complete excision.

Internal hemipelvectomy with ischiectomy, partial acetabulectomy, and femoral head and neck excision in a cat with a pelvic osteochondroma

CASE DESCRIPTION

A 2-year-old 5.1-kg (11.2-lb) castrated male Siberian cat was examined because of a history of an abnormal right pelvic limb gait and a 4- to 5-month history of progressive constipation. Radiographs obtained by the referring veterinarian showed an osteoproductive and osteolytic bony lesion that involved the right ischium and filled the obturator foramen.

CLINICAL FINDINGS

A hard mass was palpable in the right inguinal area, and rectal examination revealed a smooth bony mass on the ventral aspect of the right pelvic floor with marked reduction in the pelvic canal space. A 3.9 × 3 × 4.6-cm, mineralized mass bridging the right obturator foramen was present on CT images. The ventral component of the mass was slightly larger than its dorsal component, and lysis of the right pubic bone was present. There was no obvious soft tissue involvement.

TREATMENT AND OUTCOME

A limb salvage procedure involving internal hemipelvectomy with ipsilateral ischiectomy, contralateral partial ischiectomy, ipsilateral partial acetabulectomy, and femoral head and neck excision was performed. Histologic examination revealed that the mass was an osteochondroma. The cat recovered well and had good functional limb use immediately after surgery. The cat was still alive 1 year after surgery with good limb use.

CLINICAL RELEVANCE

Internal hemipelvectomy involving ischiectomy, partial acetabulectomy, and femoral head and neck excision can result in a good functional outcome in cats if the procedure is planned appropriately with a full understanding of the regional anatomy and adherence to surgical oncologic principles.

Hemipelvectomy to treat sarcoma of the proximal portion of the femur in a rabbit

CASE DESCRIPTION

A 7-year-old sexually intact female rabbit was admitted to the hospital because of a 6-month history of chronic right pelvic limb lameness.

CLINICAL FINDINGS

Clinical examination revealed a prominent right pelvic limb lameness and signs of pain on manipulation of the right hip joint, with a focal, well-defined soft tissue mass palpable in the right pelvic area. Pelvic radiography revealed a lytic hip joint lesion and CT detailed an expansile lesion within the proximal portion of the femur with an appearance consistent with a soft tissue mass. Histologic evaluation of incisional biopsy samples of the soft tissue mass revealed a poorly differentiated sarcoma.

TREATMENT AND OUTCOME

A hemipelvectomy was performed, and histologic evaluation of the soft tissue mass confirmed the diagnosis, with tumor-free margins achieved. The patient recovered well from surgery and had good mobility. The patient survived 21 months after surgery and died of a non-cancer-related disease. Anatomic dissection was described in a cadaver rabbit to aid future surgeries.

CLINICAL RELEVANCE

To the authors' knowledge, this was the first report of a hemipelvectomy performed in a rabbit. Hemipelvectomy is more routinely performed in canine and feline patients, but with the right candidate and owner commitment to aftercare, it may be safely and successfully performed in rabbits.

Preoperative autologous blood donation and transfusion in dogs undergoing elective surgical oncology procedures with high risk of hemorrhage

OBJECTIVE

To describe preoperative autologous blood donation (PABD) and transfusion in dogs undergoing elective surgical oncology procedures with a high risk of intraoperative hemorrhage.

STUDY DESIGN

Prospective study.

ANIMALS

Twelve dogs.

METHODS

Dogs undergoing surgical oncology procedures associated with a high risk of hemorrhage were enrolled. Blood was collected a minimum of 6 days before surgery and separated into fresh frozen plasma (FFP) and packed red blood cells (pRBC). Dogs received FFP at the start of surgery and pRBC intraoperatively when hemorrhage ensued. The mean packed cell volume/total solids (PCV/TS) were calculated on the day of PABD preoperatively, immediately postoperatively, and 24 hours after transfusion. The dogs were monitored for transfusion-related adverse reactions, including hyperthermia, hypotension, tachycardia, bradycardia, pale mucous membranes, prolonged capillary refill time, or tachypnea/dyspnea.

RESULTS

Dogs enrolled in the study underwent mandibulectomy, maxillectomy, chest wall resection, and liver lobectomy. Ten of the 12 dogs that underwent PABD received autologous transfusion at first signs of hemorrhage intraoperatively. Iatrogenic anemia was noted in two dogs (PCV 30% and 31%). The mean PCV/TS levels on the day of blood collection, preoperatively, immediately postoperatively (after transfusion), and 24 hours posttransfusion were 45.1%/7.1 g/dL, 42.2%/6.73 g/dL, 33.2%/5.42 g/dL, and 36.5%/5.65 g/dL, respectively. No dog developed transfusion-related complications.

CONCLUSION

Preoperative autologous blood donation was well tolerated and led to uneventful autologous transfusion in 10 of 12 dogs.

CLINICAL SIGNIFICANCE

Preoperative autologous blood donation and autologous transfusion are feasible for dogs undergoing elective surgical procedures with a high risk of hemorrhage.

Aneurysmal bone cyst in the pelvis of a cat: successful outcome of partial iliectomy with limb preservation

Case summary

A 3-year-old spayed female domestic shorthair indoor cat presented with a 3-week history of pain from the pelvic region. Physical examination revealed pain elicited on palpating the pelvic area and right hip. Radiographs and CT showed an expansile, osteolytic process with intact cortex in the right wing of the ilium. CT revealed a monostotic and soft tissue-attenuating process with clear margins. Preoperative histopathological diagnosis of aneurysmal bone cyst was made from incisional biopsies. The cyst was removed en bloc with limb-sparing partial iliectomy. Histopathology confirmed the diagnosis of aneurysmal bone cyst. Recovery from surgery was uneventful. At re-examination 8 weeks and 8 months postoperatively, the cat was pain free and physical examinations were within normal limits.

Relevance and novel information

Feline aneurysmal bone cysts are rare and reported cases are few. To our knowledge, this is the first report describing the CT appearance of a pelvic aneurysmal bone cyst and partial iliectomy with limb preservation in a cat with successful short-term outcome.

Suspected Radiation-Induced Osteosarcoma in a Domestic Shorthair Cat

A 3-year-old, male neutered domestic shorthair cat, presented for acute onset tail paresis. He was diagnosed with a spindle cell tumour at the level of L7-CD1 and treated with course fractionation radiation therapy. Three years following radiation therapy, the cat developed chondroblastic osteosarcoma of the pelvis, suspected to be secondary to radiation therapy. Hemipelvectomy was performed and the cat was treated with radiation therapy for remaining gross disease. The cat was euthanized 127 days post-operatively due to suspected metastatic disease. Development of radiation-induced tumours should be considered as a rare late complication in cats undergoing radiation therapy.

Iliectomy with limb preservation for a dog with ilial osteosarcoma: Surgical description and case report

OBJECTIVE

To report the surgical technique for iliectomy and outcome in a single clinical case.

STUDY DESIGN

Case report.

ANIMAL

A 10-year-old female spayed Rottweiler.

METHODS

A dog presented with left pelvic limb lameness due to a mass involving the left ilium. Fine needle aspirates were indicative of a sarcoma and suspicious for osteosarcoma. Computed tomography of thorax, abdomen, and pelvis was performed as well as skeletal scintigraphy, with no evidence of metastasis seen. The dog underwent iliectomy with preservation of the ipsilateral limb and was ambulatory 24 hours after surgery. Results of histopathology confirmed the diagnosis of an osteosarcoma.

RESULTS

A right ischial fracture was noted 8 days postoperatively and was conservatively managed. Local recurrence was reported 385 days postoperatively, with no overt metastatic disease revealed by computed tomography of the thorax and abdomen. The dog was euthanized because of local recurrence 430 days after surgery.

CONCLUSION

Iliectomy was well tolerated in this dog and afforded good function of the pelvic limbs. Local recurrence developed with no evidence of metastasis at the last follow-up. Iliectomy can be considered for a mass confined to the ilium when preservation of the limb is desired. Additional studies are required to determine the local recurrence and complication rates associated with this procedure in dogs with axial skeletal osteosarcoma.

CLINICAL SIGNIFICANCE

To the authors' knowledge, this case report represents the fist surgical description and clinical outcome for an iliectomy in dogs.

Hemipelvic and proximal femoral limb salvage endoprosthesis with tendon ongrowth in a dog

OBJECTIVE

To report the clinical application of a hemipelvic and proximal femoral endoprosthesis for limb salvage.

STUDY DESIGN

Retrospective case report.

ANIMAL

One 5-year-old, neutered female, flat coated retriever with a malignant neoplasia of the left coxofemoral joint.

METHODS

An invasive soft tissue mass (histiocytic sarcoma) with bone lysis of the femoral head and acetabulum was noted on radiographs, computed tomography (CT), and MRI. Custom-designed hemipelvic and proximal femoral endoprostheses were produced from CT images and manufactured with hydroxyapatite coated surfaces to allow tissue integration. The proximal femoral implant allowed tendon ongrowth and muscle attachment. The pelvic implant was anchored to the ilium and ischium with screws, and the femoral implant was cemented. Chemotherapy consisted of lomustine (CCNU).

RESULTS

No evidence of implant loosening or local/thoracic metastases was noted on radiographs or CT at 6 weeks and at 3, 6, 9, and 12 months after surgery. A neurapraxia resolved 14 weeks postoperatively. Intensive rehabilitation was performed. At 12 months, activity was unrestricted with minimal residual lameness. The dog was euthanized at 14 months for metastatic disease.

CONCLUSION

Limb salvage with a hemipelvic and proximal femoral endoprosthesis resulted in limb function and survival for 14 months.

CLINICAL SIGNIFICANCE

Neoplasia involving the bones of the coxofemoral joint traditionally requires hemipelvic resection and pelvic limb amputation. This report provides evidence that limb salvage can result in satisfactory levels of activity.

Soft tissue sarcoma in the dog - part 1: a current review

Soft tissue sarcomas are derived from tissues of mesenchymal origin. Although local recurrence following surgical resection is the characteristic challenge in their management, 40% dogs with high-grade tumours may also develop metastatic disease, despite successful local control. Soft tissue sarcoma is a complex disease and there are many uncertainties regarding the biology and optimal clinical management. There are currently no diagnostic tests that can reliably predict the amount of surgical margin required for a particular tumour, so there can be a mismatch between treatment and disease. Historically, the tendency has been to always recommend wide excision margins but this is not fully supported by recent evidence. A selection bias for less aggressive soft tissue sarcomas in primary care practice can account for good outcomes that are achieved despite narrow surgical excision margins. On the other hand, inappropriately conservative treatment will adversely affect outcomes for patients with more aggressive disease. This review provides an update on the current understanding of management of canine soft tissue sarcomas.

Description of the Anatomy, Surgical Technique, and Outcome of Hemipelvectomy in 4 Dogs and 5 Cats

OBJECTIVE

To provide (1) a comprehensive description of hemipelvectomy; and (2) report clinical application and outcome of hemipelvectomy in dogs and cats.

STUDY DESIGN

Descriptive report and retrospective case series.

ANIMALS

Dogs (n = 4) and 5 cats.

METHODS

Cadaveric dissection was performed for imaging purposes using 4 mixed breed dogs euthanatized for reasons unrelated to this study. Medical records (2005-2012) were reviewed for dogs and cats that had hemipelvectomy. Data collected included signalment, body weight, body condition score, clinical presentation, diagnostic imaging findings, location and extent of tumor, definitive diagnosis, use of adjuvant therapy, ability to ambulate postoperatively, complications, and survival.

RESULTS

The most common indication for hemipelvectomy in cats was injection site sarcoma (ISS) and in dogs, osteosarcoma or peripheral nerve sheath tumor (PNST). Complete tumor excision was achieved in 6 (67%) cases. Incomplete excision occurred in 2 dogs with lumbosacral PNST and 1 cat having a 2nd surgery for ISS. Complications included intraoperative hemorrhage (n = 2), postoperative soft tissue infection (2), and discharge from the incision site (1). All but 1 animal were ambulatory at the time of discharge. Hospitalization ranged from 1-10 days (median, 4 days). Survival after surgery was individually assessed.

CONCLUSION

With in-depth anatomic familiarity, hemipelvectomy can be successful for excision of neoplastic lesions of the proximal aspect of the pelvic limb, with only minor complications.

Ischiectomy With Limb Preservation for a Dog With Ischial Chondrosarcoma: Case Report and Surgical Technique

OBJECTIVE

To describe the surgical technique for ischiectomy in the dog and to report the procedure in a case.

STUDY DESIGN

Case report.

ANIMAL

An 11-year-old spayed female mixed breed dog with chondrosarcoma of the ischium.

METHODS

The dog presented for hindlimb lameness and evaluation after a radiographic finding of a lytic lesion confined to the left ischium. Following staging and confirmation of stage 1 disease, an ischiectomy with preservation of the hindlimb was performed.

RESULTS

The dog recovered from surgery and was initially moderately lame on the hindlimb. Over time, the dog regained satisfactory hindlimb use and was alive >500 days postoperative with no evidence of local recurrence or metastatic disease.

CONCLUSIONS

Ischiectomy with hindlimb preservation is a technically straight-forward procedure and in this case, resulted in good hindlimb function postoperatively. The procedure should be considered for the treatment of dogs with bone tumors confined to the ischium.

Primary cranial mediastinal hemangiosarcoma in a young dog

Primary cranial mediastinal hemangiosarcomas are uncommon tumors. A 30-kg, 2-year-old, intact female German shepherd was presented for evaluation of cachexia and respiratory distress of a few days’ duration. Lateral radiographic projection of the thorax revealed significant pleural effusion. Computed tomography revealed a cranial mediastinal mass effect adjacent to the heart. On surgical exploration, a pedunculated mass attached to the esophagus, trachea, brachiocephalic trunk, left subclavian artery and cranial vena cava without attachment to the right atrium and auricular appendage was removed and debrided by use of blunt dissection and dry gauzes, respectively. Histopathology results described the cranial mediastinal mass as hemangiosarcoma. At 8 months and 5 days post-operatively, the patient died. Primary cranial mediastinal hemangiosarcomas, although a seemingly rare cause of thoracic pathology in young dogs, should be considered in the differential diagnosis for pleural effusion and soft tissue mass effect in the cranial mediastinum. This is the first case report in a dog to describe primary cranial mediastinal hemangiosarcoma.