Introduction
The idea of looking inside the body is old but surgeons had to wait until 1806 (first cystoscopy by Bozini) to be able to perform it. Then, one had to wait until the early 20th century to take the risk of entering the abdomen (Kelling in Dresden, 1901). The first human laparoscopy was carried out only 12 years later and the same surgeon, Jacobaeus from Stockholm, already practised thoracoscopy to section pleural adhesions. But, for the adventure to go on, one had to wait for new technologies: cold light (Fourestier, Gladu and Vulmière, 1952), video cameras and optic fibers to relay the image on a monitor (1980). In the meantime, gynecologists, under the influence of Bruhat (Clermont-Ferrand), switched from diagnosis to treatment and performed a good number of gynecological procedures. Surgeons were more timid. In 1987 Mouret and Dubois, in Lyon, successfully realized the first laparoscopic cholecystectomy. This gave the real start to mini-invasive surgery. Yet, in humans, mini-invasive surgery has become the gold standard for many operations. The development of new instruments has allowed more sophisticated surgeries to be done. Use of robots has become the rule for many surgeries and even tele-surgery can now be performed.
The advantages of mini-invasive surgery have been described and usually comprise:
Smaller incisions
Better visibility
Less post-operative pain
Shorter hospital stay
Given all these theoretical advantages and pressure from the public, veterinarians began to take part in the adventure: they switched from experimental to real patients and from diagnosis to treatment. In human surgery, the first evidence-based medicine studies are just coming out. Yet although many of the techniques validated for humans have also been described in the dog, large numbers are still lacking and most of the veterinary work is concentrated on feasibility protocols and evaluation of post-recovery behaviors.
Since mini-invasive surgery requires specific training and specific material, and as the operating costs and durations can be higher and carry specific anesthetic constraints, one can really ask the question: laparoscopy and thoracoscopy, is it for the practitioner?
Specific Requirements of Mini-Invasive Surgery
Mini-invasive surgery requires a specific material: a tiltable surgical table, a complete video setting with a 0-30° thoracoscope and laparoscope, a mono or three CCD camera and recording material. In the abdominal cavity and, in some instances, the thoracic one, an insufflator will also be used. An electrosurgical unit with uni- and bipolar cautery for endoscopic instruments, as well as irrigation and vacuum systems, are necessary. All types of endoscopic instruments must also be available: laparoscopic and thoracoscopic trocars, endograspers, endodissectors and endoretractors. Although feedback-controlled electro-cautery devices are now widely used, endosutures and endoligatures, as well as endoclips and surgical staples, are necessary for some procedures.
Mini-invasive surgery requires a 'working space' to be able to manipulate the instruments without damaging intra-cavitary organs. In laparoscopic surgery, this space is obtained by insufflating carbon dioxide into the abdominal cavity, creating a pneumoperitoneum. In thoracoscopic surgery, the space can be created in several ways. An infusion of carbon dioxide unilaterally at a maximum pressure of 3 cm of water may be sufficient to moderately collapse the lung and work efficiently without compromising the gas exchange. Unilateral ventilation with pulmonary exclusion using specific endobronchial devices can also be used but require more monitoring and anesthetic equipment. Therefore, as with human neonates and infants, thoracoscopic techniques without pulmonary exclusion are being developed. Monitoring the patient during the procedure is mandatory and requires an anesthetist (nurse or vet) and instrumental equipment: spirometer, EKG, pulse oximetry and, moreover, capnography. Finally, beside the list of instruments and settings, starting with mini-invasive surgery requires learning and experience. A new philosophy of surgery where the minimum morbidity is the rule must be gained and, for this, hours, days and weeks of specific training are necessary.
Current Indications of Laparoscopy and Thoracoscopy in Small Animals
Exploratory Examination and Biopsies
Several studies have been conducted and validate the superiority of laparoscopic-obtained biopsy samples compared to fine needle or ultrasound guided biopsies. Liver, kidney and spleen biopsies can be easily performed using a two- or one-hole laparoscopy. Intestinal biopsies are best made by laparoscopic-assisted techniques. In the chest, with the patient in dorsal recumbency or after the creation of a 3 mm Hg pneumothorax, pleural or lung biopsies can be performed.
Partial or Total Organ Ablation and Drainage
Laparoscopy offers several advantages over conventional laparotomy for elective surgeries such as cryptorchidectomy, ovariectomy or ovario-hysterectomy. In several studies, post-operative behavior using behavior scales have validated the superiority of laparoscopic ovariectomy over regular ovariectomy. Besides the traditional three-hole techniques, two- and one-hole techniques have been described and offer great cosmetic advantages. Intra-abdominal removal of pathologic organs have also been performed e.g., cholecystectomy, adrenalectomy, pancreatic tumors. In the chest, thoracoscopic pericardectomy offers major advantages over traditional trans-sternal or trans-thoracic approaches.
Many other procedures have been performed: colposuspension, jejunostomy tube insertion, partial or total lung lobectomies, PDA closure, ligamentum arteriosum removal, thymoma removal. Drainage of intra-abdominal or intra-thoracic diseases can also be facilitated using a scope and a video monitor.
Other Developments: Video-Assisted Procedures
Indications for laparoscopic-assisted or video-assisted thoracic surgery are currently expanding. In these cases, the surgical approach is minimized thanks to the use of the video. A part of the procedure is actually performed out of the natural cavity: lap-assisted gastropexy, lap-assisted cystotomy, video-assisted lobectomy.
Complications of Mini-invasive Surgery
Before starting with mini-invasive surgery, one should be aware of the most common complications. Many of the pre-operative ones relate to material dysfunctions because of lack of consistency in handling the material.
Peri-operative complications include:
Organ trauma due to inadvertent puncture from Verres needle, trocar or electrocautery.
Thermal injuries due to inadvertent firing of the electrocautery or coupling capacity.
Hemorrhage: In this latter case, use of suction devices, appropriate coagulation devices and experience are needed. A hemorrhage that would not be readily controlled requires a conversion.
Post-operative complications are usually rare and are mostly represented by dehiscence of trocar wounds closure.
Laparoscopy and Thoracoscopy: Is it for the Practitioner?
Does Mini-invasive Surgery Present Any Advantage to the Patient?
On many elective surgeries (ovariectomy, ovario-hysterectomy, cryptorchidectomy), as well as on some specific procedures (pericardectomy), pain scores and behavior scores have been shown to be in favor of the mini-invasive approach. In other procedures validations are still lacking because of the lack of sufficient cases. Nevertheless, the trend is that mini-approaches, if not detrimental to the patient, reduce pain and morbidity.
What are the Advantages for the Owners?
The idea of mini-invasive surgery, as well as the idea of offering the state-of-the-art technology, pushes the owners to ask for mini-invasive surgeries. They easily compare human surgery with veterinary surgery and expect for their pet to have what they themselves would want.
Can the Practitioner Benefit From It?
Over the years, placing a scope into a cavity has brought a tremendous amount of information. The practitioner willing to start with mini-invasive surgery should start with rigid endoscopic examination: urethro-cystoscopy, otoscopy, rhinoscopy, laryngo-pharyngoscopy and bronchoscopy. Then, further progress can be achieved by performing intra-abdominal biopsies, e.g., liver, lymph node and pancreas. Once this has been done, elective surgeries can be offered: ovariectomy, cryptorchidectomy. After enough experience has been collected, intra-thoracic biopsies and pericardectomy can be the next steps.
Conclusion
Over the past twenty years mini-invasive surgery has represented a major progress in diagnosis and treatment of surgical diseases. In small animal surgery, practitioners shall benefit from it and shall offer it to their clients. Going step by step, getting trained in training centers and not being too ambitious when getting started are key for efficient progress and success.
References
References are available upon request.