Approach to Robotic, Transabdominal, Left Hemi-Diaphragm Plication

Summary

This manuscript reviews the surgical approach and the steps to perform a robotic, transabdominal left hemi-diaphragm plication.

Abstract

Impaired contractility of the diaphragm can occur secondary to diaphragm paralysis. Signs and symptoms of diaphragm paralysis vary among patients. Some may be asymptomatic and present incidentally, while others experience dyspnea secondary to impaired ventilation. Patients who are symptomatic from diaphragm paralysis may benefit from surgical intervention with diaphragm plication. Many surgical approaches are available for diaphragm plication, including open, thoracoscopic, laparoscopic, and robotic-assisted procedures. In this paper, we discuss our step-by-step approach to a robotic, transabdominal diaphragm plication. This was performed in a 60-year-old female presenting with dyspnea secondary to left hemidiaphragm paralysis. The technique includes inducing an iatrogenic pneumothorax to create a pressure equilibrium between the thoracic and peritoneal spaces. Subsequently, a diaphragm plication is performed in a 2-layer approach, using an initial running suture and subsequent reinforcing interrupted sutures in two separate axes, namely the posterior and anterior axes. Lastly, the plication repair is verified through the use of a thoracic port, which is subsequently used for tube thoracostomy placement.

Introduction

Diaphragm dysfunction can result from diaphragm paresis, paralysis, or, more rarely, eventration¹. Diaphragm paresis or paralysis refers to partial or complete loss of the diaphragm’s contractile ability, most commonly secondary to phrenic nerve damage, which may result in impaired ventilation and dyspnea. For symptomatic patients with persistent diaphragm paralysis, diaphragm plication is an effective surgical approach resulting in a significant decrease in dyspnea, notable improvement in pulmonary function tests (PFT), and better functional status^2,3.

Prior to considering a surgical repair, the patient is carefully evaluated with PFTs, a sniff test, and chest computed tomography imaging. This workup is essential to rule out other potential causes of dyspnea or impaired ventilation. Patients with diaphragm dysfunction will generally demonstrate an approximate 30% decrease in their forced vital capacity on PFTs and a 20% to 50% decrease in their lung volume when going from an upright to a supine position^4,5. Patient medical co-morbidities and surgical history should be meticulously assessed to help guide the surgical approach and ensure the ability to tolerate general anesthesia. Evaluation of surgical history is necessary to determine the risk of adhesive disease.

Repair of the diaphragm can be approached in various ways^3,4,6. These include transthoracic or transabdominal approaches, using minimally invasive or open techniques to plicate the diaphragm. Both open and minimally invasive techniques can yield successful diaphragm plication and symptom improvement. However, minimally invasive techniques have been associated with decreased post-operative pain and hospital length of stay⁷.

Diaphragm plication is most commonly and increasingly performed through minimally invasive techniques, including robotic, thoracoscopic, or laparoscopic approaches. A recent meta-analysis identified no significant difference in surgical outcomes between minimally invasive techniques⁸. Deciding between a transabdominal or transthoracic approach is dependent on the surgeon's expertise as well as the patient's surgical history and comorbidities. With a transthoracic approach, single-lung ventilation is required, which may preclude some patients with poor cardiopulmonary reserve. Adhesive disease in patients with prior thoracic surgeries may dictate the need for a transabdominal approach, while those with a significant history of abdominal surgeries may be best treated with transthoracic approaches. Right-sided hemi-diaphragm paralysis patients may be best served by a transthoracic approach, as the liver may limit operative space.

In this paper, we review the technical steps to performing a transabdominal, robotic-assisted, left-sided diaphragm plication. Our technique involves performing the plication along a vertical axis posteriorly and a horizontal axis anteriorly. While there is some evidence supporting the safety and feasibility of this technique, it remains relatively underreported in the literature and is not widely adopted by thoracic surgeons. Nevertheless, it represents a valuable addition to the thoracic surgeon’s armamentarium and may offer an important alternative in select clinical situations.

Case Presentation

The patient is a 60-year-old female who presented to the pulmonologist for a persistent cough and dyspnea on exertion. A raised left hemidiaphragm was identified on diagnostic imaging (Figure 1). She was then referred to the thoracic surgery clinic for consideration of plication.

Diagnosis, Assessment, and Plan

Her evaluation included sitting and supine PFTs, which showed a decreased forced expiratory volume in one second (FEV1) of 0.69 L while sitting and 0.48 L while supine (decrease of 11% of predicted) and forced vital capacity (FVC) of 0.82 L sitting and 0.56 L supine (decrease of 10% of predicted). A sniff test demonstrated no paradoxical movement and no downward movement of her left hemidiaphragm with breathing or sniffing. These findings were consistent with left hemidiaphragm paralysis. She underwent pulmonary rehabilitation as part of her pre-operative optimization due to her significantly compromised PFTs. Of note, her body mass index (BMI) was 26. After prehabilitation, she continued to experience significant respiratory symptoms. A cardiac and pulmonary workup revealed no other pathology. The decision was then made to proceed with a diaphragm plication for her symptomatic left hemidiaphragm paralysis. Due to a previous surgical history of left thoracotomy for patent ductus arteriosus ligation, a transabdominal approach was elected for this patient.

Protocol

On the day of surgery, written informed consent was obtained from the patient for the procedure, and verbal consent was obtained to videotape the procedure and use this data for possible publication. Per the University of Minnesota institutional review board guidelines, this project is categorized as Not Human Subjects Research (NHSR). All data was presented in a completely anonymized and de-identified format, ensuring no direct or indirect tracking of human subjects. All ethical protocols for data handling and privacy were strictly observed.

1. Pre-operative Evaluation

1. Routine preoperative diagnostic evaluation included sitting and supine PFTs, two-view chest radiographs, and fluoroscopic sniff testing to visualize the diaphragm’s function during respiration.
2. A chest computed tomography (CT) was obtained to rule out other confounding etiologies. CT imaging can also help to differentiate a diaphragm hernia from diaphragm elevation.
   NOTE: Additional tests, such as diaphragm ultrasound and electromyography, are not routinely used in the authors’ practice. However, these tests can be helpful in scenarios of diagnostic uncertainty, depending on institutional practice.
3. Typically, the indication for surgery is symptomatic diaphragm elevation, and all other testing is ancillary.

2. Pre-operative Optimization

1. Once it was determined that the patient had symptomatic diaphragm paralysis and could benefit from a diaphragm plication, other contributory issues were meticulously addressed.
2. A cardiopulmonary workup was performed to rule out any coexisting pathology contributing to dyspnea.
3. All patients with a BMI greater than 35 are referred to a weight management clinic. A long-term follow-up study of diaphragm plication patients identified morbid obesity (BMI > 35) as a contributing factor for reduced or lack of symptom improvement after plication⁹. This patient’s BMI was 26, and she was deemed optimized from this perspective.

3. Pre-operative Counseling

1. During the pre-operative clinic visit, the risks and benefits of the procedure were discussed in detail, including, but not limited to, major respiratory events, arrhythmia, bleeding, infection, need for reoperation, pulmonary embolism, cardiac event, and death.
2. The hospital course was reviewed with the patient, including the plan for pain control, thoracostomy tube management, and the estimated timeline of hospitalization.

4. Operative Set-up 

1. General anesthesia with a single lumen endotracheal tube was used since lung isolation was not required with a transabdominal approach. 
2. The patient was positioned supine on the operative table with arms extended. A footboard was placed to allow for safe reverse Trendelenburg positioning to 30°–45° during the operation.
3. The abdomen, as well as the ipsilateral chest, were included in the operative field for access through the chest. 
4. This procedure was performed using a robotic approach. Instruments are listed in the Table of Materials.
5. Port placement and docking
   1. The abdomen was accessed using an insufflation needle at Palmer’s point, and an optical trocar was used for initial entry into the abdominal cavity (see Table of Materials). Carbon dioxide insufflation was used to reach a pneumoperitoneum of 12 mmHg using a flow rate of 40 L/min.
   2. Once that was achieved, ports were introduced under direct visualization using the laparoscope. Four 8 mm laparoscopic ports and one laparoscopic assistant port were required. Ports were placed approximately 10–12 cm inferior to the xiphoid. An 8 mm port was inserted in the supraumbilical region.
   3. Three additional 8 mm trocars were then inserted in a horizontal line across the patient’s abdomen along the same line, slightly above the level of the umbilicus. The ports were centered on the side to be plicated.
   4. A 12 mm assistant port, used primarily for additional retraction, insertion, and removal of sutures and gauze, and suction of fluids in the operative field, was placed inferior and left-lateral to the umbilicus (Figure 2). Once port placement was deemed satisfactory, the robot was docked.
   5. The robotic camera was placed in port 3 and angled 30˚ up. Targetting was achieved by centering on the middle of the hemi-diaphragm to be plicated. A bipolar grasper was placed in port 1, an atraumatic robotic grasping forceps in port 2, and a fenestrated grasper in port 4.
   6. One 10 mm thoracic port was placed in the 6^th or 7^th intercostal space for eventual transthoracic verification of the plication upon completion. The anesthesia team was asked to hold ventilation for a few seconds and, using an optical trocar, a port was inserted in the thoracic cavity. This was subsequently used for the placement of a tube thoracostomy once the repair was complete.
6. Iatrogenic pneumothorax
   ​NOTE: Due to the diseased nature of the diaphragm and increased intra-abdominal pressure caused by the pneumoperitoneum, the hemi-diaphragm gets displaced cephalad, making it difficult to grasp and manipulate for the repair (Figure 3).
   1. A small defect was created in the dome of the diaphragm to induce a pneumothorax, equilibrate the pressures between the thoracic and intra-abdominal cavities, and make the diaphragm lax. Using forceps, the diaphragm was grasped and retracted caudally.
   2. An appropriate location in the dome of the diaphragm was identified. This location should be amenable to incorporation within the final plication line. Using bipolar forceps, electrocautery, and a coagulation setting of 8, a small hole, approximately 1 to 2 cm in size, was made until there was visualization of the intra-thoracic cavity.
      ​NOTE: If there is concern about a tension capnothorax, insufflation pressure should be reduced immediately. Of note, the presence of the thoracic port placed at the beginning of the procedure helps ensure a controlled environment. This can be used as a venting port and allows the surgeon to effectively control intrathoracic pressures.
7. Posterior diaphragm plication
   1. The redundant diaphragm was grasped at its most posterior location and retracted caudally.
   2. Robotic port 4 was used for the needle driver. A pleat was then created with the redundant tissue to perform a plication line along the posterior axis (Figure 4). Using a #0 non-absorbable, knotless, barbed suture, the diaphragm was approximated and tightened in a running, locking manner starting proximally and extending posteriorly (Figure 5).
   3. The plication line was then reinforced using several interrupted, pledgeted #2 Ti-Cron, horizontal mattress sutures (Figure 6). These were placed at 1 to 2 cm intervals. The total number of these reinforcing sutures was dependent on the length of the plication line.
8. Anterior diaphragm plication 
   1. The anterior plication was accomplished in a similar manner. Using a non-absorbable, knotless, barbed suture, the diaphragm was plicated along a vertical axis and reinforced with # 2 pledgeted non-absorbable polyester sutures. Of note, this plication line incorporates the diaphragmatic defect created at the initiation of the procedure, ensuring closure of the defect.
   2. The tautness of the diaphragm plication was assessed along the suture line. The abdominal insufflation pressure was reduced to a pressure of 8 mmHg. The diaphragm was then tapped along the plication line with a grasper, ensuring it did not pull away from the costal margin, which would indicate residual laxity. Additional reinforcing sutures can be placed as needed in areas of laxity.
9. Transthoracic verification of plication
   Once the plication was complete, plication lines were again assessed via the thoracic port, ensuring that the lung tissue was free and the repair was performed adequately, especially posteriorly (Figure 7). 
10. Tube thoracostomy placement:
    Using the thoracic port location, a 19 French silicone chest drain was inserted in the left pleural cavity to manage any remaining pneumothorax and to drain any effusion that might accumulate in the new space in the post-operative period (Figure 8).

5. Pearls and Pitfalls

1. Steep reverse Trendelenburg positioning with a slight upward lateral tilt on the operative side moved the bowel away and offered better visualization.
   CAUTION: During the creation of the diaphragmatic defect, care was taken not to injure intra-thoracic organs, including lung parenchyma and the heart.
2. Communication with the anesthesia team was crucial to allow for close monitoring of blood pressure and ventilation throughout the case, but in particular during creation of the iatrogenic pneumothorax. Safety considerations included ventilation difficulties and hypotension caused by increased intrathoracic pressure.
3. The iatrogenic diaphragmatic defect was included in the plication sutures to close the defect as part of the procedure.
   CAUTION: Care must be taken to avoid injury to surrounding structures during plication. These include the liver parenchyma, hepatic veins, inferior vena cava, and esophagus for right-sided plications, and the stomach, spleen, and colon for left-sided plications.
4. The surgeon periodically checked for tautness along the attachment of the diaphragm to the costal margin to ensure that there was no undue tension.
5. As the diaphragm became progressively taut, insufflation pressures were reduced to reassess tension and more accurately determine the required extent of additional plication. 
6. Transthoracic visualization at the end of the procedure helped evaluate the adequacy of posterior plication.
7. The surgeon considered the patient’s surgical history when selecting the operative approach, as prior procedures on either side of the diaphragm might have led to adhesions that reduce diaphragmatic compliance and limit effective plication.
8. During a transabdominal approach, a non-pliable diaphragm might have suggested adhesions on the thoracic surface. In such cases, extending the diaphragmatic defect can facilitate lysis of thoracic-side adhesions to improve mobility and allow adequate plication. If sufficient results are still not achieved, conversion to a thoracic approach (e.g. thoracotomy) is considered. 

6. Post-operative care 

1. The chest tube is removed once appropriate lung re-expansion is confirmed and the output is less than 300 mL in a 24-h period. In this patient, the tube was removed on post-operative day 3.
2. Crucial to the post-operative care of the thoracic patient is robust pulmonary hygiene with deep breathing, coughing, and incentive spirometry. Multimodal pain control and early mobilization are also strongly recommended.
3. The plication is assessed radiologically with a posteroanterior and lateral chest radiograph prior to discharge. 
4. A scheduled bowel regimen is implemented to avoid constipation and straining, which could disrupt the repair.
5. Patients are educated regarding important post-operative concerns that may warrant urgent evaluation, including worsening chest pain and shortness of breath, both at rest and with exertion. Some level of dyspnea can be expected up to two months after surgery as the ipsilateral lung re-expands to fill the space created from the plication.

7. Follow up

1. The plication is evaluated at 1-month and 1-year follow-up intervals with posteroanterior and lateral chest radiographs as well as sitting and supine PFTs. 

Results

Post-operative course

The patient tolerated the procedure well and was brought to the general surgical floor for routine post-operative care following completion of surgery. They required oxygen supplementation through nasal cannula until post-operative day (POD) 1, but were weaned off following the use of incentive spirometry. Tube thoracostomy remained in place due to the presence of a small air leak and a small left-sided pleural effusion (Figure 9

Discussion

Diaphragm plication is an effective surgical treatment for diaphragm paralysis in symptomatic patients. Patients can experience impaired respiratory function as evidenced by decreased PFTs and decreased respiratory quality of life, both of which have been shown to improve with diaphragm plication. Thoracic surgeons have traditionally approached the diaphragm transthoracically, through both open and minimally invasive techniques such as video-assisted thoracoscopic surgery (VATS) or robotic-assisted thoracoscopic surgery ...

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
AirSeal Insufflator Trocar, bladeless, 12x120mm	ConMed	IAS12-120LP	Laparoscopic assistant port
Cadière Forceps, 8mm, Endowrist	Intuitive Surgical	471049
Chest drainage cannister - Suction Dry Chest Water Seal Drain Shore	Alleva Medical Ltd.	ST381-0001
da Vinci Xi Surgical System	Intuitive Surgical	Model Number IS4000
DaVinci Xi seal universal 5-12MM	Intuitive Surgical	470500
Endo Dissector Kittner Cigarette Roll	Carefree Surgical Specialties	15505/25
Endo Trocar First Entry KII FIOS Z-thread, 5x100mm	Applied Medical	CTF03	Thoracic assistant port
Insulated Blade Electrode	Medtronic	E1455	Electrocautery
Jackson Pratt Round Drain, 19 Fr	Cardinal Health	JP-HUR195
Laparoscopic bowel grasper forceps, 5mm	Stryker	250-080-084
Long Bipolar Grasper	Intuitive Surgical	471400
Mega SutureCut Needle Driver, 8mm	Intuitive Surgical	471309
Monocryl suture, 4-0, PS-2, undied	Ethicon	Y426H
Needle Insufflation, 13 GA, 150mm	Applied Medical	C2202
Pledgets, soft TFE polymer	Ethicon	D7044
Silk suture, #0, SH needle	Ethicon	K834H
Silk suture, #2-0, SH needle	Ethicon	K833H
Silk tie, #0	Ethicon	A306H
Surgical blade, #15	Bard-Parker	371115
Surgicel SNoW Absorbable Hemostat	Ethicon	2083
Ti-Cron suture, #2, GS-21 taper needle, braided, non-absorbable	Covidien	3146-81
Tip-Up Fenestrated Grasper, 8mm	Intuitive Surgical	470347
Tissue retrieval system, 12mm introducer trocar	ConMed	TRS-ROBO-12
Vicryl suture, #0, UR6 needle, VLT	Ethicon	VCP603H
Vicryl suture, #2-0, SH needle, undied	Ethicon	J417H
V-Loc suture, #0, GS-21 needle, 9 inches, Non-absorbable	Medtronic	VLOCM0346
Wayne Pneumothorax Tray, 29cm	Cook Medical	G56537	Thoracostomy catheter