Robotic abdominal and thoracic surgery in children

Introduction

Pediatric general and thoracic surgical conditions cover a wide range of diagnoses that span the breadth of being congenital, infectious, malignant, or acquired. The combination of increasing surgeon experience and advances in surgical technology have resulted in the successful application of minimally invasive techniques in the treatment of almost all conditions.

History

Open approaches were the mainstay of surgical treatment until the 1980s when endoscopic techniques gained popularity in abdominal and thoracic surgery. The applications of straight stick endosurgery (SSE) grew rapidly over the years with techniques for intestinal, pulmonary, and complex biliary surgery being described. With improvements in instrumentation through optimization of ergonomics and miniaturization, minimally invasive techniques were applied to even the smallest of neonates. In 2001, the Frankfurt Group reported the first successful application of the robotic platform in pediatric surgery by performing a Nissen fundoplication. Since then, multiple authors have performed and subsequently reported their experiences on robotic abdominal and thoracic surgery in children.

Benefits

The benefits of robotic surgery for abdominal and thoracic surgery in pediatric patients include and surpass some of the advantages of SSE. Similar to SSE, robotic surgery allows for smaller incisions and improved cosmetic outcomes, decreased postoperative pain and therefore limited opioid use, shorter length of stay, and decreased time to return to school and other activities.

Robotic surgery, however, has several added benefits that differentiate it from SSE. From an optical standpoint, the platform provides an enhanced, magnified, three-dimensional visualization that surpasses the magnification provided by loupes or traditional two-dimensional endoscopes. Additionally, the operating surgeon can manipulate both the camera and the robot’s remaining arms, allowing for optimal visual angles without requiring assistants. From a mechanical standpoint, one of the significant advantages of the platform is that instruments can be “locked in position” by the user at their discretion. This allows for a robust, reliable, and indefinite amount of retraction or control. Human fatigue or motion is not an issue in retraction or maintaining exposure or control in robotic surgery.

Additionally, unlike the straight, rigid instruments used in SSE, which allow for four degrees of freedom, robotic instruments were designed to allow for seven degrees of freedom. Due to this difference in design, robotic instruments are able to function like human hands, wrists, and arms with the added benefit of tremor filtration. This allows for enhanced access to previously challenging areas of dissection, including the biliary tree and pelvis, as well as more natural movements during surgical techniques such as intracorporeal suturing. ^{, ,} Robotic surgery can uniquely facilitate enhanced, precise dissection and reconstruction of the more diminutive anatomy found in neonates and smaller children. ^,

Limitations

Despite the numerous benefits of robotic surgery, the field of pediatric general and thoracic surgery has been relatively slow to adopt this modality into practice. Much like other facets of surgery, robotic surgical systems were initially designed for adult patients. This has led to a few limitations in their application to younger pediatric patients. The primary disadvantage of robotic surgery is related to the size of the robot and its instruments relative to younger and smaller patients. ^, First, the robot itself is approximately 6 feet tall and can appear massive in relation to a neonate or toddler. This has the potential to restrict a surgical assistant’s or anesthesiologist’s access to the patient. Second, robotic instruments currently approved for pediatric use are only available in 8 mm and 5 mm sizes, which are considerably larger than the 3 mm instruments available with traditional laparoscopy for infants and toddlers. The 8 mm and 5 mm instruments use pitch-roll-yaw and snake-like mechanisms for articulation, respectively. ^{, ,} Although the 5 mm instruments are smaller, their design utilizes multiple joints to enhance their “snake-like” flexibility and articulation. This requires them to be longer, which can minimize the work space in the body cavity of a small child. ^{, ,} In addition, robotic endoscopes currently measure 12 mm or 8.5 mm. ^{, ,} These larger sizes can be prohibitive in neonatal surgery. Endoscopes of this size would likely be too large to easily and safely traverse between the rib spaces in thoracoscopic operations for children less than 5 kg. For this reason, the manufacturer briefly marketed a two-dimensional 5 mm endoscope from 2005 to 2009 to circumvent this restriction; however, it was discontinued due to lack of market penetration, as pediatric surgeons were the only physicians interested. ^,

Trocar placement in robotic surgery also differs from that of traditional laparoscopy. Traditional laparoscopy mandates the triangulation of trocars toward the target anatomy, with ergonomic benefits provided to surgeons when placing ports relatively closer together to minimize muscle fatigue and excessive stress on their shoulders. This is unnecessary in robotic surgery; however, manufacturers typically suggest eight centimeters of distance between trocars to mitigate collisions between robotic arms. This can be a challenge in infants and smaller children. Suggested trocar depth can further minimize available working space. Robotic manufacturers recommend that the remote center of the trocar be placed at the inside edge of the body cavity. The distance from the remote center to the end of the trocar measures 2.9 cm. When using even the shortest of available instruments, the distance from the inside edge of the patient to the tip of the instrument is at least 5.61 cm, which can equate to the entire width of a neonate’s hemithorax or hemiabdomen.

The benefits of robotic surgery, including increased accessibility to previously challenging anatomy, improved precision of dissection with tremor filtration, and enhanced ease of suturing and knot tying, would make robotics ideal for complex procedures in neonates, such as esophageal atresia repairs. The aforementioned limitations, however, have impaired its utilization in practice. Further research and development targeted toward the creation of finer instruments is required to facilitate further use of robotics in neonates and toddlers. In their prospective case series of 41 patients and 42 procedures, Bütter et al. performed most operations using 5 mm instruments. Interestingly, due to the lack of fine 5 mm instruments or diathermy scissors, the 8 mm instruments had to be used as well. Di Fabrizio et al.’s retrospective review of 39 pediatric patients who underwent robotic-assisted operations analyzed causes of conversion to open procedures. Three procedures were converted to open due to inadequate working space. Affected patients were of lower age (2.97 ± 1.03 vs. 9.83 ± 0.77 years, P = .01) and lower weight (11.83 ± 1.74 vs. 35.47 ± 3.16 kg, P = .03). This further emphasizes the need for innovation of smaller and finer technology for the youngest and smallest of patients.

An additional cited limitation of robotic surgery is the lack of haptic feedback relative to laparoscopic and open surgery; however, many surgeons state that this limitation is significantly mitigated by the enhanced visualization afforded by the binocular endoscope that provides a three-dimensional view. ^{, , ,}

Arguably the most prohibitive limitation of the widespread implementation of robotics in pediatric surgery is cost. ^{, ,} In addition to the initial cost of purchasing the robotic system, which could cost between 1 and 2.3 million US dollars, hospital systems must also be prepared to pay an annual service contract of 100,000 to 170,000 US dollars as well as the costs of additional disposable or replacement instruments and drapes. ^{, ,} Several pediatric institutions mitigate this cost by sharing the system with their adult hospital counterparts; however, this severely limits the time blocks available for its use per surgeon. Hospital organizations aiming to minimize costs and increase their profit margin must weigh the costs of using the robot for a given operation versus the potentially decreased costs associated with a shorter length of stay and potential marketing advantage over regional competitors.

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