Advances in Minimally Invasive Surgery
Jason Spina, DVM, DACVS-SA
Minimally invasive surgery has slowly become an integral part of human medicine since its initial use in the late 1800s. Many advances have been made, and we are now able to adopt similar techniques in veterinary medicine that allow us to explore joints, body cavities, the gastrointestinal tract, respiratory tract and the bladder.
A minimal surgical approach can have many benefits compared to a traditional procedure that make this option appealing for our patients. Most minimally invasive surgeries are performed through 1-4 small ports, 3-12 mm in diameter. Therefore, pain associated with a large incision into a joint capsule, or body cavity is minimized, and patients experience a lower requirement for postoperative pain medication, less surgical stress, fewer complications (infection, thromboembolism, wound healing) and a faster recovery. All these benefits minimize the need for prolonged hospital stays.
Minimally invasive surgery in veterinary medicine began in the 1970s with arthroscopy. Initially utilized as a diagnostic tool in horses, arthroscopy has gained respect as the gold standard diagnostic and therapeutic modality for many orthopedic conditions in cats and dogs. (See table 1.) Through the scope we can visualize placement of implants or evaluate reduction and alignment of fractures without increasing morbidity through an open arthrotomy.
Adaption into soft tissue surgery lagged and didn’t truly become integrated until the late 1990s – early 2000s.
Since that time, numerous procedures have been described utilizing the scope to evaluate body cavities. Laparoscopy utilizes the scope to explore the abdominal cavity with the help of carbon dioxide, which is used to insufflate the cavity creating a larger field of view, providing room to navigate, minimizing tissue trauma. See table 2 for additional procedures.
Thoracoscopy describes use of a scope to evaluate the thorax using ports. The creation of a small window to manually manipulate organs is called video-assisted thoracoscopic surgery (VATS). Carbon dioxide is not required for insufflation, and the procedure relies heavily on the creation of a pneumothorax or the use of one-lung ventilation to create enough working space. Therefore, more specialized anesthetic technique is often required for these procedures. The most common procedures performed are listed in table 3.
Although, a large focus on minimally invasive procedures involves the use of a scope to evaluate various structures, many other procedures can be performed with a small skin incision or no incision at all with the assistance of intra-operative imaging. Several imaging modalities have been described but commonly rely on fluoroscopy or ultrasonography for completion of the task. Soft tissue procedures include urinary stent placement; subcutaneous ureteral bypass (SUB) systems; tracheal and nasopharyngeal stents; coil embolization for intrahepatic shunts or patent ductus arteriosus; chemotherapeutic embolization for tumors; and various biopsy techniques.
Extension into orthopedics has occurred using minimally invasive plate osteosynthesis (MIPO) for fracture repair. Guided with fluoroscopy or an observational portal of the fracture site, bones are realigned using a more biologic approach and stabilized with the placement of a locking plate through two small incisions. Several studies have concluded on the benefits of this technique, which results in faster healing times (mean 30 days), lower complication rates, greater callus formation and disruption of less periosteal vasculature compared to traditional open reduction and internal fixation.
Although the benefits are numerous, several disadvantages do exist. The equipment and techniques are expensive, highly specialized and require extensive training. Training programs are beginning to emerge utilizing box trainers, simulators, and video games to develop basic skills. Many contemporary video game consoles require similar skills – improving precision, accuracy, two-hand coordination and the concept of 3D movements on a 2D screen. Lastly, not all procedures can be completed successfully through a minimally invasive approach, requiring conversion to a traditional approach for completion.
Case Example #1:
Simon is a 10-year-old golden retriever who presented to his primary veterinarian for signs of lethargy, anorexia and collapse. He was diagnosed with cardiac tamponade as a result of pericardial effusion. An echocardiogram was performed by Anthony Tobias, PhD, BVSc, DACVIM-Cardiology, to evaluate for cardiac and heart-based tumors. Happily, none were identified. However, an enlarged lymph node was identified in the cranial mediastinum. A conservative approach was elected, and the tamponade did not return until almost 6 months later. Following stabilization, another echocardiogram was performed with no obvious tumors and no changes in size of the enlarged lymph node. Staging was performed and was clear of any evidence of metastatic disease. It was elected to pursue pericardectomy and lymph node excision. Simon underwent thoracoscopic lymph node extirpation and pericardectomy. Pericardioscopic examination confirmed that there was not a right atrial mass nor a heart-based tumor. Anesthesia and recovery was smooth, and within hours of the procedure, the thoracostomy tube was removed and Simon was up, eating and ready to go home. Unfortunately, the biopsy report concluded that the lymph node was effaced with metastatic carcinoma; along with intravascular emboli within the pericardium. Prior to the ability to offer a minimally-invasive approach, Simon would have undergone a median sternotomy, spent 1-2 days in the hospital, and 2-4 weeks recovering. Within 1 week of the procedure, he was back to his normal activity and reportedly feeling great! Although his long-term prognosis is very guarded, a less invasive procedure provided a diagnosis, therapeutic benefit and a faster recovery to enjoy his time left.
Case Example #2:
Bogart (Bo) is an 8-month-old, mixed breed dog who presented for forelimb lameness exacerbated with exercise. Examination revealed bilateral pain associated with the elbows and radiographs exhibited mild signs associated with medial compartment disease or elbow dysplasia. Bilateral elbow arthroscopy was performed revealing medial coronoid disease, and debridement was performed. Bo was able to return to normal activity within 2 months following surgery. He no longer has lameness and does not require pain medication. Prior to the availability of arthroscopy, a medial arthrotomy would have been performed occasionally requiring transection of the medial collateral ligament. With the medial arthrotomy, recovery was prolonged, complications increased, and outcomes less favorable than compared to an arthroscopic approach.
If you would like to learn more about minimally invasive surgery or consult on a case you feel may benefit from a minimally invasive procedure, please feel free to contact us.