New tricks for old dogs: liposuction

Transcription

1 Vet Times The website for the veterinary profession New tricks for old dogs: liposuction Author : CATHERINE F LE BARS Categories : Vets Date : October 13, 2008 CATHERINE F LE BARS discusses how this fresh technique can be applied to the removal of lipomas in elderly dogs A COMBINATION of improved nutrition and advances in veterinary medicine means that companion animals are now living longer than ever before. As a consequence, veterinarians face the special challenges presented by a group of animals often considered higher-risk candidates for surgery and anaesthesia. Liposuction, a surgical technique used extensively within human medicine for more than three decades, has found its way into the veterinary world. This article will examine its use as an alternative to conventional surgical excision for the removal of lipomas in dogs. History Fat extraction and sculpting dates back to the 1920s, but the process failed to elicit much interest among plastic surgeons at the time because results were inconsistent and complications were not only common, but also significant. Liposuction, or suctionassisted lipoplasty (SAL), was formally introduced to the medical world in 1982 by the French surgeon, Yves-Gerard Illouz, who described performing SAL on 3,000 cases during a five-year period. SAL was soon practised widely within the United States, despite medical and cosmetic complications associated with the procedure. Advances in liposuction techniques 1 / 11

2 have reduced these risks and improved long-term results. Although the procedure has been used to treat lipomas in people, it is more commonly used for cosmetic purposes. According to statistics published by the American Society for Aesthetic Plastic Surgery, 456,828 Americans had liposuction performed on them in 2007, granting it the dubious honour of heading the list of cosmetic surgical procedures for that year. In January 2007, Böttcher et al (from the Faculty of Veterinary Medicine, University of Leipzig, Germany) presented a paper describing the first reported use of liposuction on an elderly obese dog with severe bilateral hip osteoarthritis and three large lipomas, one of which was thought to be further compromising mobility. Removal of the lipomas was achieved with the use of minimally invasive liposuction, and the dog recovered well. The significant increase in mobility postoperatively was attributed not only to the physical removal of the lipomas, but the immediate loss of 3kg, which represented 10 per cent of the dog's total bodyweight. Staff members at the University Veterinary Teaching Hospital Sydney (UVTHS) recommend liposuction for the treatment of many lipomas presented at their clinic, and have used the technique on at least 12 dogs since Brief details from two of their cases are described later. Types of liposuction The procedure, in its simplest form, involves the removal of localised fat deposits by inserting a blunt metal cannula through a small incision in the skin. This is used to mechanically disrupt the adipose tissue, which is then removed using a suction pump or syringe. Several techniques are practised in human medicine. The superwet and tumescent techniques are used most commonly, and they are considered the safest. Dry technique: no fluid is instilled into the treatment area. This form is rarely used in humans nowadays, but shows promise in veterinary medicine. Wet technique: 200ml to 300ml of isotonic dilute epinephrine solution (with or without lignocaine) instilled into the area. Superwet technique: isotonic, extremely diluted lignocaine (0.04 per cent to 0.05 per cent) and epinephrine (1:1,000,000 to 1:2,000,000) solution is instilled in volumes of 1ml to 1.5ml per millilitre of expected fat aspirate. Tumescent technique: a solution similar to the superwet solution is instilled in volumes of 3ml to 4ml per millilitre of expected fat aspirate or in volumes required to bring tissues to a palpably turgid state. In the classic form of this technique, no other form of anaesthesia is used, but many liposurgeons today usually employ epidurals, sedation or general anaesthesia. 2 / 11

3 Developments have included the introduction of ultrasonic assisted liposuction (UAL), where ultrasonic energy applied to the cannula causes the cavitation and liquification of fat in its immediate vicinity, which can then be removed more easily by standard SAL techniques. This technique has, however, been associated with full-thickness skin burns and has not been approved by the FDA. Veterinary perspective The primary application of liposuction in veterinary medicine is for the removal of lipomas, and studies have indicated that a successful outcome is most likely in simple encapsulated lipomas between 4cm and 15cm in diameter. It is not recommended for liposarcomas because the tumour will not be removed fully and there is a substantial risk of disseminating tumour cells during the procedure. It is also less likely to be of use in more chronic lipomas with fibrous trabeculae, or those infiltrating deeper tissues. Although the tumescent technique is used most commonly in human cosmetic liposuction, the dry technique appears most suitable for dogs, in which the primary aim is to achieve complete removal of the fatty tissue. Liposuction confers several advantages over more conventional surgical excision: smaller surgical wounds, reduced anaesthetic time, reduced postoperative pain and the option of removing several masses under one anaesthesia. Suitable candidates include: canines with multiple or very large lipomas; dogs presented for other procedures (in these cases, liposuction may allow the rapid removal of lipomas without significantly extending the surgical time); senior dogs or those with concurrent disease, which may not tolerate lengthy anaesthesia or heal well following extensive surgery; and dogs belonging to owners who may have objections to conventional surgical procedures. Surgical technique and postoperative care Prior to surgery ( Figure 1 ), a fine-needle aspirate (FNA) biopsy should be performed to confirm the diagnosis. It should be noted that FNA cytology will not always rule out liposarcomas. The designated area is clipped and prepared as usual for aseptic surgery. Using a number-10 scalpel blade, a stab incision is made at one extremity of the lipoma. A 7mm unsheathed Poole suction tip is introduced and suction applied ( Figure 2 ). The tip is repeatedly advanced and retracted to break down the fatty tissue. Sterile saline is used intermittently to relieve cannula blockages. Fat extraction is facilitated with digital pressure and massage of the lipoma. The procedure is 3 / 11

4 concluded when no further fat can be palpated between the cannula tip and the skin. In human medicine, advanced imaging modalities allow the determination of the lipoma's boundaries prior to removal. This is often impossible in the veterinary environment, so while removal of the capsule is attempted using forceps after liposuction, it is not always achievable. At the conclusion of the procedure ( Figure 3 ), a closed-suction drain may be inserted if a moderate haemorrhage has occurred or significant subcutaneous dead space is present. The stab incision is then closed with a non-absorbable suture material. Dressings are placed where possible. At the UVTHS, postoperative analgesia is provided by methadone boluses, determined by subjective pain scoring, and a broad-spectrum antibiotic administered for two days postoperatively. NSAIDs are used if further analgesia is required. Patients are usually discharged 48 hours after the procedure. Case one A nine-year-old male neutered Bernese mountain dog ( Table 1 ) was referred to the UVTHS for liposuction of several giant lipomas. At presentation he weighed 55.2kg and his body condition score was assessed as 5/5 (1/5 being very underweight, 3/5 ideal and 5/5 obese). He exhibited early clinical signs of osteoarthritis. A biochemistry profile provided normal results and FNA cytology of the masses confirmed them as lipomas. The majority of the 13 masses were suctioned easily and a total of 2.2L of fat removed. The largest lipoma gave the impression of containing fibrous tissue. As a consequence, haemorrhage was more pronounced and fat retrieval less effective than with the smaller lipomas. The skin incisions were sutured with 3/0 D polyamide and a Jackson-Pratt closed-suction drain was placed in the subcutaneous defect. One day postoperatively, there was mild seroma formation around several liposuction sites, a larger seroma on the left flank and serosanguinous discharge from the Jackson-Pratt drain. The drain was removed 24 hours postoperatively and a bandage placed around the thorax. By 48 hours postoperatively, the swelling had reduced a little. Two weeks after surgery, the owner reported that there was still some swelling around the brisket, but that the dog was very happy and active. Case two A 13-year-old female neutered Staffordshire bull terrier ( Table 2 ) was presented with multiple lipomas. She was 31.5kg and had a body condition score of 3.5/5. She had slowed down over the past year and her owners were concerned that the lipoma on her left thigh affected her gait and caused her pain. The referring vet had resected the left medial thigh lipoma twice, one and two years previously. The right lateral thoracic lipoma had also been resected one year ago both had recurred. Her preanaesthetic biochemistry profile showed a moderate elevation in serum alkaline phosphatase but no other significant changes. 4 / 11

5 The lipomas were suctioned under general anaesthetic. Two incisions were required to suction the left medial thigh lipoma. Large amounts of fibrous tissue throughout the central portion of the lipoma made liposuction difficult. In total, 600ml of fat was removed. Postoperative care was administered as usual. The proximal left hindleg exhibited significant swelling, but this resolved over the following few weeks. Eight months postoperatively, the lipoma on the medial aspect of the left thigh returned and caused her discomfort. The left and right lateral thoracic masses had also recurred to a lesser extent and were not bothering the dog. At this stage, she was being maintained on a NSAID for clinical signs related to osteoarthritis. On examination, the recurrent lipoma on the medial aspect of her left hindlimb was 15cm in diameter. Due to the fibrous network present within the lipoma, liposuction was not repeated. Instead, a surgical attempt was made to remove the lipoma, which was adherent to the surrounding tissues and dissecting between muscle bellies. The mass was very fibrous, making en-bloc extraction impossible, and, therefore, the more superficial portions of the mass were resected, leaving a wide margin around where the sciatic nerve was expected to be. A Jackson-Pratt closed suction device was placed in the deficit and continued to drain small volumes of serosanguinous fluid for three days postoperatively. The dog was maintained on a morphine infusion for 24 hours after surgery. A repeat biopsy confirmed the mass as a lipoma, and the dog's recovery was uneventful. Complications and risks In humans, it is estimated that one in 5,000 people die from liposuction procedures performed by certified specialists. However, since this does not take into account cases treated by nonspecialists, the actual number of liposuction-related deaths may be considerably higher. No deaths have been reported from the use of tumescent liposuction in combination with local anaesthesia only. Serious complications in people are rare but include: pulmonary thromboembolism; haemorrhage; infection; injury to intra-abdominal and/or thoracic viscera; skin necrosis; pulmonary oedema; and adverse drug reactions. Many of these complications are associated with overzealous liposuction and poor technique. Little data documenting the complications associated specifically with lipoma removal in people 5 / 11

6 exists, but one study put the incidence at 0.1 per cent, with fat embolisms occurring in only per cent of cases. Although dry liposuction is rarely, if ever, practised by human surgeons these days, its use for the removal of lipomas in the dog has, so far, been associated with few serious complications, most probably because it is used to remove discrete encapsulated areas of fatty tissue. Minor complications, such as seroma and/or haematoma formation, ecchymoses and local parathesia, have been documented but appear to resolve in time. Seroma formation is most commonly associated with the removal of lipomas from inguinal and (to a lesser extent) axillary areas. Oedema of the surgical site and seromas may persist for longer than in people, perhaps because it is often not practical to leave dressings in place for the six to eight weeks considered standard in human patients. Regrowth of the lipoma may occur (particularly with lipomas having a well-developed fibrous network) and extend into surrounding tissues and those where the capsule has been incompletely removed. In these cases, surgical excision is more appropriate. Conclusion Liposuction in companion animals is reserved for the removal of lipomas, and shows promise in those patients with multiple large lipomas, where surgical excision may carry significant and potentially prohibitive risks. At present, liposuction is not indicated for cosmetic reasons or for the treatment of obesity in companion animals, although these applications will doubtless be debated as techniques improve, client awareness increases and the procedure becomes more widely available. The author would like to thank Geraldine B Hunt for providing details of her case reports and photographs. References are available by request to the editor. 6 / 11

7 After preoperative preparation (Figure 1), an unsheathed Poole suction tip is introduced and suction applied. 7 / 11

8 (Figure 2). The tip is advanced and retracted repeatedly to break down fatty tissue. 8 / 11

9 Figure 3. In dogs with multiple or large lipomas, liposuction confers postoperative advantages over 9 / 11

10 surgical excision. TABLE 1. Location and size of lipomas (case study one) 10 / 11

11 Powered by TCPDF ( Table 2. Location and size of lipomas (case study two) 11 / 11