Through the 10-mm Looking Glass: Advances in Minimally Invasive Surgery in Trauma

Introduction

Over the past 30 years, minimally invasive surgery (MIS) has revolutionized the practice of modern surgery and has become standard for the treatment of many surgical conditions. Multiple benefits of MIS compared to traditional open surgery are well documented including less induced surgical trauma and physiologic stress, reduced in-hospital length of stay, decreased postoperative pain, and faster functional recovery, as well as improved cosmesis (1, 2). The use of MIS in trauma is not a novel concept. The initial reports demonstrating the utility of MIS in the evaluation of hemoperitoneum in patients with traumatic abdominal injuries were first published in the early 1920s (3). Decades of research examining the physiologic changes, clinical outcomes, and complications associated with MIS, along with major technological advances in optics and MIS instrumentation and surgical training, have led to near universal acceptance of MIS in all surgical specialties for both advanced elective and emergency operations. For trauma patients, MIS provides clear visualization of the thoracic cavity, the peritoneal space, and the anterior abdominal wall, and unlike other diagnostic modalities, it has the potential benefit for therapeutic intervention while also decreasing rates of unnecessary nontherapeutic procedures. Despite these clear potential advantages, MIS has yet to achieve widespread acceptance within the trauma community. Debate continues to surround both the appropriate indications and applications of MIS in the injured patient.

Several reasons may explain the delay in acceptance of MIS in trauma surgery compared to other surgical disciplines. Time is a luxury that an acutely injured patient can ill afford. The concept of quickly controlling both hemorrhage and contamination is a core concept of trauma surgery. The logistics of setting up an operating room, gaining access to an anatomic cavity, and controlling a potential source of contamination or hemorrhage is longer for a MIS procedure compared to open surgery. Temporally, most traumas occur at night and when less personnel is available, making the acceptance of equipment-dependent cases less desirable. Perhaps the most compelling argument against MIS in trauma is the potential for missed injury. Initial studies reported rates of missed injury, specifically hollow viscus, as high as 77% with diagnostic laparoscopy (DL) in trauma (4, 5). However, this is largely operator dependent, and with experience and adoption of standardized surgical techniques and technological advances, more contemporary studies have showed vastly improved clinical outcomes with DL in trauma, with reported sensitivity, specificity, and accuracy approaching 100% (6–9). These results notwithstanding, surgical training and experience with MIS will greatly influence attitudes toward MIS utilization in trauma (10).

Indications, Contraindications, and Rationale

Specific to trauma, the initial goal of MIS was to diagnose injuries and avoid nontherapeutic laparotomies. Toward this goal, laparoscopy has been used as a screening, diagnostic, and therapeutic tool in both blunt and penetrating trauma. Screening laparoscopy simply needs to detect signs of visceral injury that are subsequently repaired via laparotomy, while DL must identify all injuries as effectively as other diagnostic modalities, such as computed tomography (CT). In ideal circumstances, DL should triage patients as those without intra-abdominal injuries, those with intra-abdominal injuries that do not require operative intervention, and those who do require an operative intervention (11). Therapeutic laparoscopy must allow for the detection and repair of all injuries in order to be determined a success. Multiple successful therapeutic laparoscopic operations for acute trauma have been described (12).

MIS in trauma is generally only considered in patients with normal hemodynamics and in whom major bleeding is not expected, although contemporary studies now challenge this claim (13). Despite these results, most published evidence maintains hemodynamic instability to be an absolute contraindication to MIS in trauma and currently laparoscopy has no role in hemodynamically unstable patients (14). In addition, concomitant severe traumatic brain injury (TBI) is an absolute contraindication to laparoscopy. Both animal studies and case reports suggest that the increased abdominal pressure due to pneumoperitoneum may increase intracerebral pressure and worsen an underlying TBI (15). Relative contraindications include acute lung injury, previous laparotomy, multiple system injuries, chronic cardiorespiratory disease, and third-trimester pregnancy (8, 14).

The complications associated with laparoscopy in trauma are the same as in elective surgery, including wound infections, hernias, and iatrogenic injuries. Tension pneumothorax from positive pressure pneumoperitoneum is the most common complication of laparoscopy seen in patients with diaphragmatic injuries and tube thoracostomy should immediately be placed in those cases (11). Patients with intra-abdominal venous injuries are also at a theoretical risk of gas embolism (16). Overall the reported complication rate with laparoscopy in trauma is <1% (4, 9).

Screening and DL

The decision and timing of laparotomy in hemodynamically stable patients with suspected intra-abdominal injuries secondary to either blunt or penetrating trauma is a major challenge. Despite multiple diagnostic tools available to aid surgeons in making these decisions, rates of both negative and nontherapeutic exploratory laparotomies for trauma remain as high as 30% (17, 18). While the risks of missed injury and delayed operation are potentially disastrous, the morbidity associated with nontherapeutic or negative laparotomies is reported as high as 41% and is also associated with increased health-care cost and hospital length of stay (19, 20). DL has shown substantial utility in diagnosing intra-peritoneal pathology in trauma. Compared to exploratory laparotomy, laparoscopy has demonstrated a specificity of 98%–100% (21, 22).

Most commonly, DL is used as a tool to evaluate for peritoneal violation in penetrating trauma and left-sided diaphragmatic rupture in both blunt and penetrating trauma (6, 7, 12, 14, 21, 23). A recent systematic review of 51 studies on the role of laparoscopy in penetrating abdominal trauma reported a sensitivity of 66.7%–100%, specificity from 33.3%–100%, and accuracy from 50%–100% with over 50% of the most contemporary studies reporting sensitivity, specificity, and accuracy approaching 100% (9). Approximately 30% of patients with peritoneal penetration do not have intra-abdominal injuries and screening laparoscopy may still lead to high nontherapeutic laparotomy rates (24, 25). However, use of DL in a systematic standardized approach for the evaluation of intra-abdominal injuries rather than as a simple screening test for peritoneal violation is reported to spare 73% of nontherapeutic laparotomies (8).

Diaphragmatic injuries occur in up to 20% of patients with penetrating thoracoabdominal injuries (26). In isolated left-sided thoracoabdominal penetrating wounds, without any other indications for surgery, these injuries may often be missed. The consequences of missed diaphragmatic injury can be devastating and include potential herniation and strangulation of viscera through the diaphragmatic defect. DL has a specificity, sensitivity, and negative predictive value of 100%, 87.5%, and 96.8% in the evaluation of the diaphragm after penetrating injury (21, 26). As such, DL should be considered in patients with left-sided thoracoabdominal penetrating wounds with no other indications for laparotomy.

Following blunt abdominal trauma, hemodynamic instability and a positive focused abdominal sonography for trauma (FAST) or diagnostic peritoneal lavage (DPL) mandates urgent laparotomy. DL is useful in hemodynamically normal patients who are not in need of immediate exploratory laparotomy and with equivocal imaging findings (free fluid, mesenteric fat stranding, bowel wall thickening, distended bowel loops) and the patient’s clinical status is only suspicious or unexaminable. DL offers excellent visualization of the peritoneal cavity, assessment of free intra-peritoneal fluid, and identification of intra-peritoneal injuries. Use of DL in these patients allows for a precise identification for therapeutic exploratory laparotomy, having a sensitivity of 94.1%–100%, a specificity of 91%–100%, and an accuracy of 96%–97.2% (4, 27). Rates of nontherapeutic laparotomy are reduced by up to 78% with using laparoscopy as a diagnostic adjunct. Specific to small bowel injury, DL is superior to CT scan when only indirect signs of injury are relied upon (28, 29). CT scan has a sensitivity of 82%–95% and a specificity of 98% for diagnosing intestinal injuries (30). A contemporary systematic review of DL in blunt abdominal trauma demonstrated a 0% missed intestinal injury rate and reported significantly reduced hospital length of stay (27).

The risk of missing injuries is the most commonly cited reason, limiting the widespread use of laparoscopy in trauma. Early reports supported these concerns, publishing missed injury rates of 41%–77% when laparoscopy was used as a diagnostic tool to perform abdominal exploration (4). However, this is secondary to several factors including operator experience and comfort with laparoscopy and the available technological resources. Contemporary reports paint a very different picture with reported missed injury rates with DL approaching <1% (6–9, 27). The value of a standardized examination for laparoscopy to achieve this result has been demonstrated in both blunt and penetrating trauma (8, 31). This highlights that the utility of laparoscopy as a diagnostic tool likely relies most heavily on the skill of the operating surgeon. Performing 20 laparoscopic procedures per month for acute care surgery is a predictor of a surgeon’s ability to safely and accurately perform DL for abdominal stab wounds (32). Although it is clearly possible to use DL with an acceptably low missed injury rate, if a surgeon is lacking the technical skill required to properly perform the procedure or if a suspected injury to hollow viscus cannot be thoroughly evaluated laparoscopically, then immediate conversion to laparotomy is mandatory.

Therapeutic Laparoscopy

Although current management guidelines limit the role of laparoscopy to screening and diagnosis, many authors have challenged this notion and reported successful use of the laparoscope for therapeutic interventions in trauma (21). Prior to 2000, only three published studies described their experience with laparoscopy as a therapeutic tool (4). Since then an impressive amount of work has been published advocating for the therapeutic utility of laparoscopy in trauma. Laparoscopic repair to virtually every organ has been described, including diaphragm, stomach, small intestine, colon, bladder, pancreas, and spleen with impressive results. Chol and Lim (12) reported a 56% success rate treating bowel perforations with laparoscopic and laparoscopically assisted procedures. Lin et al. (32) successfully performed therapeutic laparoscopy in 16 of 17 hemodynamically normal patients with significant intra-abdominal injuries secondary to abdominal stab wounds including hemostasis of bleeding solid organs and mesenteric injuries, repair of diaphragm lacerations, and repair or resection and anastamosis of perforated hollow organs. Cherkasov et al. (13) reported that of 1332 abdominal trauma patients evaluated with DL, successful therapeutic laparoscopy was performed in 30.8% of patients including most of the previously mentioned procedures with an average laparoscopic surgical time of 60 ± 30 min. The evolving therapeutic role of laparoscopy in trauma ensures its continuing relevance, but the ultimate acceptance of therapeutic MIS in trauma surgery will depend on the skill set of the individual surgeon. Increasing comfort with MIS, continued participation in acute care surgery, and technological advances will allow trauma surgeons to better use and study MIS as a therapeutic tool in patients requiring interventions.

Diagnostic and Therapeutic Thoracoscopy

Thoracic trauma accounts for approximately 25% of all trauma-related death, especially in patients who die at the scene, mostly from injuries to the heart and great vessels. Of the chest injuries, 80%–85% can be treated with resuscitation and tube thoracostomy alone, while the remaining 15%–20% of patients sustaining thoracic trauma go on to require operative interventions (33). However, a significant burden of morbidity and mortality in these patients is secondary to complications of thoracic trauma including pulmonary contusion, acute respiratory distress syndrome, ventilator-associated pneumonia, empyema, and mediastinitis (34). With the evolution of MIS, video-assisted thoracoscopic surgery (VATS) has become an increasingly popular diagnostic and therapeutic modality in thoracic trauma. VATS first gained popularity among trauma surgeons as a diagnostic tool for suspected diaphragmatic injury after penetrating thoracoabdominal trauma. In 1976, Jackson and Ferreira first described the use of thoracoscopy in trauma patients as a diagnostic tool for suspected diaphragmatic injuries in patients with penetrating injury to the left chest (35). In 1981, Jones et al. (36) performed emergency thoracoscopy under general anesthesia in 36 patients with high output from chest tubes placed for hemothorax. Thoracotomy was avoided in 44% of these patients. Currently, VATS is indicated post-trauma for the diagnosis and repair of diaphragmatic injuries, management of persistent pneumothorax, retained hemothorax, empyema, and control of bleeding in hemodynamically stable patients. Compared to thoracotomy, VATS is reported to have fewer postoperative complications, better postoperative pain control, fewer wound and pulmonary complications, shorter chest tube duration, and a faster return to regular activities (37).

Injuries to the diaphragm secondary to trauma remain a diagnostic challenge. Reported missed injury rate in penetrating thoracoabdominal trauma is between 10%–30%. Chest radiographs may be normal in as high as 77% of these patients (38). Patients with these injuries and without other indications for laparotomy or thoracotomy often remain asymptomatic and may present later in life with incarcerated or strangulated diaphragmatic hernias, associated with significant morbidity and mortality. Given this, some authors advocate for mandatory exploration in all patients with mechanism suspicious for diaphragmatic injury. VATS affords a high degree of sensitivity and accuracy in the diagnosis of diaphragmatic injury due to both blunt and penetrating injuries and allows for repair of these via a minimally invasive approach. Martinez et al. (38) reported on the utility of VATS for evaluation and repair of suspected diaphragmatic injury in 52 patients with penetrating thoracoabdominal injuries not requiring emergency surgery. In all, 67% of patients had a diaphragmatic injury diagnosed by VATS, and 100% of these injuries were successfully repaired thoracoscopically. Long-term follow-up showed no missed injuries or recurrences post-thoracoscopic repair.

Proponents for the thoracoscopic approach for diaphragm repair advocate that VATS has several diagnostic and therapeutic advantages over laparoscopy, including better visualization of the entire hemi-diaphragm, especially on the right side, evacuation of blood and clot from the pleural space, and chest tube placement under direct vision (39). However, the largest series published on VATS for suspected diaphragmatic injury after penetrating trauma (n = 171) found that 78% of these patients had an associated intra-abdominal injury, with the majority of diaphragmatic injuries being repaired via the abdomen (40). Patients sustaining thoracoabdominal injuries with no clear indication for urgent operation and who are subsequently managed nonoperatively with serial abdominal examination should be observed for a minimum of 24 h prior to undergoing VATS for suspected diaphragmatic injury in order to insure that there is no occult intra-abdominal injury present (21).

VATS is especially useful in the associated complications of thoracic trauma including retained hemothorax, persistent pneumothorax, empyema, and thoracic duct injuries. Often hemothoraces will liquefy and be drained via thoracostomy tube. Conversely, retained or persistent hemothoraces will develop a fibrous exudate and form a fibrothorax, resulting in entrapped lung, significant volume loss of functioning lung, and possibly respiratory insufficiency, pneumonia, and empyema (41). After failure of initial chest tube placement for hemothorax, conventional treatment is to place additional chest tubes; however, failure rate of this procedure in resolving the hemothorax is as high as 41% (42). A recent systematic review on the utility of VATS post-thoracic trauma demonstrated an overall 87% success rate (range = 75%–100%) in evacuating retained hemothoraces and an 11% (range = 0%–25%) conversion rate to thoracotomy (43). Both hospital length of stay and costs were also drastically reduced with the use of early VATS. The reduction of empyemas after evacuation of a retained hemothorax is an important marker for the efficacy of VATS. In the 18 studies reviewed, only one study reported the presence of empyema (14%) post-VATS for retained hemothorax (43). Evacuation of purulent empyema can also often be achieved using VATS, although a formal decortication of the lung frequently requires a thoracotomy (34).

The optimal timing to perform VATS for retained hemothorax remains controversial. Several studies suggest that patients treated with tube thoracostomy but remain with a retained hemothorax 48–72 h post-trauma should be considered for VATS (34). Delaying VATS more than 5 days post-trauma results in significantly higher rates of both empyema and thoracotomy. However, these studies were retrospective and the only prospective randomized multicenter trial failed to identify any relationship between timing of VATS and success rate (42). The authors concluded that the optimal timing for VATS in post-traumatic retained hemothorax is unknown. Independent predictors of successful VATS as definitive treatment were absence of an associated diaphragm injury, use of periprocedural antibiotics for thoracostomy placement, and volume of residual hemothorax ≤ 900 cc.

Traumatic pneumothoraces typically resolve with tube thoracostomy and reestablishment of pleural to pleural apposition through closed suction. Persistent post-traumatic pneumothoraces occur in approximately 10% of patients and is typically secondary to either a pulmonary parenchymal disruption that is not able to heal or a failure of the lung to fully expand due to a retained hemothorax or fibrin deposition (44). Persistent pneumothorax is traditionally treated with prolonged chest tube drainage. The use of multiple or long-standing chest tubes results in pain, and increases potential morbidity and length of hospital stay. The use of VATS to treat recurrent and persistent pneumothorax from bullous disease is well established (45). VATS allows for direct visualization and repair of the air leak via stapling or with suture or sealant. In a series of 39 patients with persistent air leak, early VATS resulted in a decreased number of chest tube days and length of hospital stay (46). A significant air leak that has persisted beyond 72 h should be investigated by bronchoscopy to rule out the presence of tracheobronchial injury, and if no such injury is identified, then these patients should go on to VATS and definitive repair (34).

Ongoing thoracic bleeding post placement of tube thoracostomy is often an indication for thoracotomy. Most commonly this is secondary to ongoing bleeding from intercostal vessels secondary to rib fractures and chest wall trauma. Additional sources of bleeding include pulmonary parenchymal injuries or pulmonary vascular injuries. In hemodynamically normal patients, VATS may be successfully used as both a diagnostic and therapeutic tool for persistent intra-thoracic bleeding post-thoracostomy placement. Villavicencio et al. (47) reported on 40 patients with nonhemodynamically significant intra-thoracic hemorrhage and reported an 82% success rate at controlling hemorrhage by VATS. As always, hemodynamic instability is an absolute contraindication to MIS and the surgeon should absolutely proceed to thoracotomy.

Conclusion

Minimally invasive surgical techniques are continuously evolving but remain limited in acute trauma surgery. Current evidence supports the utility of MIS as both a diagnostic and therapeutic tool in select groups of hemodynamically normal patients. Despite recent challenges by some authors, hemodynamic instability remains an absolute contraindication to MIS in trauma. Recent literature has demonstrated the utility of both diagnostic and therapeutic MIS in trauma; however, the majority of published studies are retrospective and lack well-defined control groups. More robust prospective studies are needed to further investigate the beneficial effects of therapeutic MIS in trauma. Current recommendations from the European Association for Endoscopic Surgery state that DL may be considered in patients after abdominal trauma (B and C level of data reliability) (48). The Eastern Association for the study states that DL may be considered in penetrating abdominal trauma suspicious of intra-peritoneal penetration or diaphragm injury (Class 2 recommendation) (21).

MIS does offer several advantages compared to traditional open surgery and should be considered as an additional tool in the trauma surgeon’s armamentarium in the care of select injured patients. Further research will continue to characterize the optimal timing and indications for MIS in trauma. In order to remain proficient in MIS, trauma surgeons should actively participate in elective or acute care surgery to maintain their laparoscopic skills.