- Email: [email protected]
Can surgeon’s hand be replaced with a smart surgical instrument in esophagectomy?
Medical Hypotheses 73 (2009) 735–740
Contents lists available at ScienceDirect
Medical Hypotheses journal homepage: www.elsevier.com/locate/mehy
Can surgeon’s hand be replaced with a smart surgical instrument in esophagectomy? Siamak Hajizadeh Farkoush, Siamak Najarian * Artificial Tactile Sensing and Robotic Surgery Lab, Center of Excellence of Biomedical Engineering, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
a r t i c l e
i n f o
Article history: Received 7 February 2009 Accepted 11 February 2009
s u m m a r y Esophageal cancer is the eighth most common cancer in the world. The most common surgical procedures for esophageal cancer are transhiatal esophagectomy and transthoracic esophagectomy. Thoracic esophagectomy involves an abdominal incision and a thoracotomy, but transhiatal esophagectomy involves both an abdominal incision and a cervical incision. It can reduce postoperative morbidities and fast recovery. In transhiatal esophagectomy, part of dissection is blind and lack of sufficient vision during operation increases the dangers of this kind of surgery. In this paper, we propose a hypothesis about replacing surgeon’s hand with surgical instrument in esophagectomy. The proposed instrument is one-forth of surgeon’s hand volume and it can surround the esophagus radially. So, it would be able to sheer and dissect all the adhesive tissues around the esophagus. For determining possible threshold of causing traumas in delicate tissues during esophagectomy, various tactile sensors can be incorporated into the surgical instrument to detect and control the contact force of the instrument with delicate biological structures. For evaluating the proposed hypothesis, we analyzed the function of the instrument with finite element method and finally we constructed an initial prototype of the designed instrument. Ó 2009 Elsevier Ltd. All rights reserved.
Introduction In the United States, the reported mean incidence of esophageal cancer in patients younger than 80 years is 3.2 per 100,000 persons, with an overall male-to-female ratio of 3:1 [1–3]. The incidence of esophageal cancer increases with age and the tumor occurs more often in African Americans than in whites [4,5]. The two predominant histological subtypes of esophageal cancer are adenocarcinoma and squamous cell carcinoma [6]. Once a tumor is identified and the histopathology is established, evaluation of the extent of invasion is necessary for staging and for selecting therapeutic options. This work-up includes computed tomography (CT) of the chest to exclude lung parenchyma or mediastinal involvement [7]. Treatment options include surgery, chemotherapy, and radiation therapy. These therapies can be used individually or, in some instances, together to improve outcomes. Treatment approaches depend on the location of the primary tumor, the disease stage, patient characteristics, and co-morbidities. Occasionally, histological subtypes also impact decisions regarding treatment [7–10]. Surgical resection of the esophagus for cancer is a technically demanding procedure. It usually involves removing part or all of the esophagus, part of the stomach, lymph nodes in the surround* Corresponding author. Tel.: +98 21 64542378; fax: +98 21 64542350. E-mail addresses: [email protected] (S.H. Farkoush), [email protected] (S. Najarian). 0306-9877/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.mehy.2009.02.045
ing area, and occasionally the spleen (if it is injured or bleeding). In the absence of widespread metastases, surgical resection of the esophagus for squamous cell and adenocarcinoma is preferred in most centers. The most common surgical procedures for esophageal cancer are transhiatal esophagectomy and transthoracic esophagectomy. Thoracic esophagectomy involves an abdominal incision and a thoracotomy, but transhiatal esophagectomy involves both an abdominal incision and a cervical (neck) incision, and the thoracic cavity is not opened [4,7,11]. During the 1970s, Orringer introduced the technique of transhiatal esophagectomy, which avoids thoracotomy [12]. In transhiatal esophagectomy, the abdominal component of the procedure involves complete mobilization of the stomach. Lymph nodes around the distal part of the esophagus, the gastric cardia, and the left gastric artery are resected in continuity with the specimen. The intrathoracic part of the esophagus is then dissected away from adjacent thoracic structures by using a blunt technique. To perform this maneuver, the surgeon opens the diaphragmatic hiatus and mobilizes the esophagus by careful manual dissection up into the thoracic cavity [4]. However, the use of an open approach has not clearly demonstrated the reduction of the risk of postoperative respiratory complications or postoperative mortality. In addition, part of the dissection is ‘‘blind” with the consequent risk of bleeding, particularly from the azygos vein, and damage to the trachea and bronchi. With the development of minimally invasive surgery, attempts were made to use alternative minimally invasive methods for
736
S.H. Farkoush, S. Najarian / Medical Hypotheses 73 (2009) 735–740
esophageal dissection [13–15]. However, combined methods using thoracoscopic dissection with conventional abdominal approaches have not achieved a significant reduction in respiratory morbidity, mostly due to the upper midline abdominal incision [11,16]. Considering that postoperative pulmonary complications are mainly caused by the prolonged deflation of the right lung during the operation and that midline abdominal and thoracic incisions compromise respiratory ability, scientists tried to avoid laparotomy and thoracotomy using the laparoscopic transhiatal approach. This approach could reduce postoperative morbidities and fast recovery [11]. Laparoscopic transhiatal esophagogastrectomy has many advantages. The estimated blood loss is minimal and it has no intraoperative complications. The operative time is shorter than in the other approaches. There are no intraoperative ventilation difficulties. The patients are ambulated early and there are no postoperative pulmonary complications. However, in spite of various advantages of Orringer technique in transhiatal esophagectomy, it has some limitations. In this technique, as shown in Fig. 1 [4], surgeon’s hand is entered in the patient’s thorax blindly. Hence, considering large size of the surgeon’s hand versus finite volume of thorax, and also, existence of some delicate biological structures in the thorax, such as aorta artery, lungs, airways, and trachea, transhiatal esophagectomy is a high risk operation. Lack of sufficient vision during operation increases the dangers of this kind of surgery. Additionally, in some cases that cancerous tissues are more adhesive, this type of surgery is more dangerous. For example, when there is high adhesion between tumoral tissue and aorta artery, surgeon may injure the aorta while dissecting
esophagus away from adjacent thoracic structures, and it may cause bleeding during and after the surgery. This is also true for lungs and other thoracic structures. In the Orringer technique, complete laparatomy is necessary. Considering various risks of this method and in order to decrease the size of abdominal incisions, some minimally invasive surgical approaches to esophagectomy have been reported. These involve laparoscopic and thoracoscopic techniques. In 2003, Horgan and colleagues reported their initial experience with a case of robotically assisted transhiatal esophagectomy [17]. In robotic systems, the vision is three-dimensional and surgical tools have movable wrists. So, performing a robotic endosurgery is easier than performing an endosurgery using handheld surgical tools. However, in both robotic and handheld models, it is easier to access the esophagus through upper part of the thorax cavity and dissect the tissues. But, as there is not enough vision and work space behind the esophagus, there is not enough safety even in performing a robotic surgery. In this paper, we propose a hypothesis about replacing surgeon’s hand with surgical instrument in esophagectomy. Hypothesis Our proposed hypothesis is about designing a surgical instrument which can be used in esophagectomy. The proposed instrument would be able to imitate surgeon’s hand movement for dissecting adhesive tissues and of course it would be smaller than surgeon’s hand. The proposed surgical instrument would be entered into the patient body through a 5 cm incision in the abdomen and so, as a result of minimizing the incisions in this concept, replacing surgeon’s hand with this surgical instrument in transhiatal esophagectomy can play a key role in improvement of transhiatal esophagectomy and converting this surgery to a minimally invasive surgery. In this hypothesis, we focus on designing a surgical instrument with fingers consisting of rotational joints which can sheer and dissect the tissue just like the surgeon’s fingers. For the better dominance in the thorax, it is also possible to equip the instrument with a handle as the substitute of the surgeon’s arm. Then the instrument can be inserted into thorax from the distal part of esophagus and it can go up to its proximal part to do the dissection process. As the instrument surrounds the esophagus completely and moves longitudinally along this organ, it can access entire surface of the esophagus. To have a more accurate control on the movement of the instrument head dynamic fingers, it is suggested to equip the instrument with a lever that can be controlled by the
Handle
The Instrument Head
Dynamic Fingers Fig. 1. Orringer technique in transhiatal esophagectomy [4].
Fig. 2. Different parts of the proposed instrument.
Lever
S.H. Farkoush, S. Najarian / Medical Hypotheses 73 (2009) 735–740
surgeon. Different parts of the designed instrument are shown in Fig. 2. The instrument head consisted of two parts, each part has five dynamic fingers. The two parts, firstly, are unhooked and turns into a hollow cylinder embedding esophagus by means of a locking mechanism (Fig. 3). So, the surgical instrument can surround the esophagus radially and dissect the adhesive tissues. In this case, the instrument is situated in the distal part of esophagus. The geometry and situation of the instrument’s fingers cause an ability to perform environmental dissection of the adhesive tissues, while going ahead. When the instrument reaches a sticky area, it sheers the tissue up to about 7 cm and dissects the probable adhesions. The way that the proposed instrument dissects the adhesive tissues is shown in Fig. 4.
737
force of tissues. These sensors can detect whether the surgical instrument apply forces beyond the allowed limit during the surgery and warn it to the surgeon. Considering some tactile sensors on the proposed instrument, possible threshold of causing traumas in delicate tissues during transhiatal esophagectomy can also be determined. Hence, the proposed instrument can be called a smart surgical instrument. Because of limitations of dimension, tactile sensors should be very small and so, we should use an array of FSR sensors on the fingers of the instrument. FSR sensors consist of a thin PVDF film that its electrical resistance reduces as a result of applying pressure. There is an approximately linear relationship between variations of electrical resistance of sensor and variations of applied forces. Therefore, the amount of force applied per unit area can be measured with acceptable accuracy.
Modifying the hypothesis by installing some tactile sensors Finite element analysis The artificial tactile sensing is a new method for obtaining the characteristics of a tumor in the soft tissue [18–20]. This includes detecting the presence or absence of a tumor or even mapping a complete tactile image [21–23]. Robotic minimally invasive surgery represents the most fascinating opportunities in the area of modern diagnostic and therapeutic possibilities in robotic surgery. The need to detect various tactile properties justifies the key role of tactile sensing which is currently missing in MIS [24]. With regard to artificial tactile sensing in medical robotics, the on-line measurement of variable contact forces that occurs during a robotic manipulator’s interaction with the biological tissue is of great importance [20]. This can be achieved by using various kinds of miniaturized sensors, most often mounted on the instrument. In spite of many advantages of MIS (such as, less pain, reduction of trauma, faster recovery time, smaller injuries, and post operation complications), it reduces the tactile sensory perception of the surgeon during grasping or manipulation of biological tissues [20,25]. The proposed surgical instrument will be in direct contact with delicate biological tissues and it is applicable in dissecting the adhesion of adjacent tissues, in esophageal surgery. Also, since the surgery is not open, it is necessary to provide the surgeon with suitable feedback, such as a sense of the amount of force exerted on the biological tissues. Therefore, the designed instrument can be equipped with tactile sensors capable of measuring contact
For evaluating the proposed hypothesis, we analyzed the function of the proposed instrument with finite element method. For finite element modeling of esophagus and the tissues around it, we attributed mechanical properties to each delicate tissue around esophagus such as aorta artery. So, by applying mechanical movement on these tissues, their possible traumas and injuries can be determined. Mechanical behavior of tissues during operating the surgical instrument on them is modeled as well. The achieved results can be used for preventing the risk of applying extra displacement on delicate tissues and decreasing their possible injuries. In fact, we can estimate the behavior of tissues as a result of motion of the instrument and the causing displacement in tissues and the amount of forces that in each moment is applied on the tissue by the instrument. So, the surgeon can prevent applying more pressure on the tissue before causing injury to it. In software modeling, we can determine the threshold of causing an injury in tissue. Hence, while the instrument is dissecting the tissues around the esophagus, a series of tactile sensors are needed to measure the amount of force which is applied on related tissues by the surgical instrument. By comparing the output data of tactile sensors with the results of software modeling, valid and low risk operation of the instrument can be guaranteed.
Fig. 3. Two parts of the proposed instrument head. The two parts firstly are unhooked and then turn into a hollow cylinder embedding esophagus by means of a locking mechanism.
738
S.H. Farkoush, S. Najarian / Medical Hypotheses 73 (2009) 735–740
Fig. 4. The way that the proposed instrument dissects the adhesive tissues.
For modeling the mechanical behavior of tissues in finite element method, mechanical properties of tissues are required. The mechanical properties can be determined through mechanical tests. Most of these tests would be performed to determine stress–strain curve. After determining the stress–strain curve, finite element model should be selected according to general characteristics of tissue. These models are mechanical models of tissues such as elastic model, hyperelastic model, and viscoelastic model. The finite element software that we used for analysis of our proposed instrument is ABAQUS. We considered elastic behavior for tissues. As there is high adhesion between tumoral tissue and aorta artery, surgeon may harm the aorta while dissecting esophagus away from adjacent thoracic structures, and it may cause bleeding during and after the surgery. Hence, we modeled the effect of the instrument on aorta while dissecting the adhesive tissues. For dissecting the tissues, the fingers of the designed instrument can be opened up to 7 cm and finite element analysis showed that this displacement will not cause any trauma in aorta artery. In
fact, we can estimate the behavior of aorta artery as a result of movement of instrument and the applied displacement. The amount of forces applied on the tissues is achieved from tactile sensors installed on the instrument. The amount of stresses caused in aorta artery, esophagus and the tumor is calculated in ABAQUS and its contour is shown in Fig. 5. Constructing an initial prototype for investigating the hypothesis For evaluating the proposed hypothesis and investigating how the instrument works, we constructed an initial prototype of it. The instrument has 10 fingers and each finger has a rotational joint. The fingers should have a synchronized radial motion. Head of instrument is made of two half-cylindrical parts and every part is linked to five fingers to each other by a locking mechanism and hence making a complete cylinder (as shown in Fig. 3). By using the locking mechanism, the instrument can surround the esophagus completely.
Fig. 5. Stress contour of aorta, calculated in ABAQUS.
S.H. Farkoush, S. Najarian / Medical Hypotheses 73 (2009) 735–740
739
Fig. 6. An initial prototype of the proposed instrument in different positions.
Diameter of the head of instrument is dynamic and can be changed easily as a result of radial motion of fingers. The dynamic diameter is 15–70 mm. The important specification of the proposed instrument is the way that it dissects the tissues. First, the instrument surrounds the esophagus and then locking mechanism makes the head of the instrument like the hallow cylinder. So, esophagus is positioned in the center of the cylindrical head. Surgeon controls the instrument while it is moving along the esophagus. In this stage, diameter of the dynamic head is about 20 mm. When instrument makes contact with adhesive tissues, rotational joint of fingers moves and diameter of head becomes about 70 mm. Because of this specification, the proposed instrument can dissect adhesive tissues away from esophagus. For actuating the rotational joints of the instrument, a lever should be used. This lever is controlled by the surgeon’s hand. In order to transfer the lever motion to fingers of the instrument, cable drive mechanism would be used. The prototype is made of medical grade steel and so it is biocompatible. Fig. 6 shows an initial prototype of the proposed instrument in different positions. Conclusion In this paper, we proposed a hypothesis about replacing surgeon’s hand with surgical instrument in transhiatal esophagectomy. The proposed instrument would be able to imitate surgeon’s hand movement for dissecting adhesive tissues. It would be entered into the patient body through a 5 cm incision in the abdomen and it surrounds the esophagus radially and sheers and dissects all the adhesive tissues around the tumor and esophagus. The instrument is small and one-forth of surgeon’s hand volume. For determining possible threshold of causing traumas in delicate tissues during esophagectomy, various tactile sensors can be incorporated into the surgical instrument to detect and control the contact force of the instrument with delicate biological tissues. For evaluating the proposed hypothesis, we analyzed the function of the instrument with
finite element method and we also constructed an initial prototype of the designed instrument to investigate how works. Acknowledgement We would like to express our gratitude to the Center of Excellence of Biomedical Engineering of Iran based in Amirkabir University of Technology, Faculty of Biomedical Engineering for its contribution. References [1] Fumoto S, Hiyama K, Tanimoto K, et al. EMP3 as a tumor suppressor gene for esophageal squamous cell carcinoma. Cancer Lett 2009;274:25–32. [2] Kamangar F, Dores GM, Anderson WF. Patterns of cancer incidence, mortality, and prevalence across five continents: defining priorities to reduce cancer disparities in different geographic regions of the world. J Clin Oncol 2006;24:2137–50. [3] Pickens A, Orringer MB. Geographical distribution and racial disparity in esophageal cancer. Ann Thorac Surg 2003;76:S1367–9. [4] Mackenzie DJ, Pepperell PK, Billingsley KG. Care of patients after esophagectomy. Crit Care Nurse 2004;24:16–31. [5] Quinn KL, Reedy A. Esophageal cancer: therapeutic approaches and nursing care. Semin Oncol Nurs 1999;15:17–25. [6] Toshiyuki Sakaeda T, Yamamori M, Kuwahara A, Nishiguchi K. Pharmacokinetics and pharmacogenomics in esophageal cancer chemoradiotherapy. Adv Drug Deliv Rev 2009;61(5):388–401. [7] Layke JC, Lopez P. Esophageal cancer: a review and update. Am Family Phys 2006;73:2187–94. [8] Jackson C, Starling N, Chua YJ, Cunningham D. Pharmacotherapy for oesophagogastric cancer. Drugs 2007;67:2539–56. [9] Siewert JR, Ott K. Are squamous and adenocarcinomas of the esophagus the same disease? Semin Radiat Oncol 2007;17:38–44. [10] Khushalani N. Cancer of the esophagus and stomach. Mayo Clin Proc 2008;83:712–22. [11] Dulucq JL, Wintringer P, Mahajna A. Totally laparoscopic trans-hiatal gastroesophagectomy for benign diseases of the esophago gastric junction. World J Gastroenterol 2007;13(2):285–8. [12] Orringer MB. Transhiatal esophagectomy without thoracotomy for carcinoma of the thoracic esophagus. Ann Surg 1984;200:282–8. [13] Cuschieri A. Thoracoscopic subtotal oesophagectomy. Endosc Surg Allied Technol 1994;2:21–5.
740
S.H. Farkoush, S. Najarian / Medical Hypotheses 73 (2009) 735–740
[14] Dexter SP, Martin IG, McMahon MJ. Radical thoracoscopic esophagectomy for cancer. Surg Endosc 1996;10:147–51. [15] Watson DI, Davies N, Jamieson GG. Totally endoscopic Ivor Lewis esophagectomy. Surg Endosc 1999;13:293–7. [16] McAnena OJ, Rogers J, Williams NS. Right thoracoscopically assisted oesophagectomy for cancer. Brit J Surg 1994;81:236–8. [17] Horgan S, Berger RA, Elli EF, Espat NJ. Robotic-assisted minimally invasive transhiatal esophagectomy. Am Surg 2003;69(7):624–6. [18] Galea AM. Mapping tactile imaging information: parameter estimation and deformable registration. Cambridge, MA: Harvard University; 2004. [19] Dargahi J, Najarian S. Advances in tactile sensors design/manufacturing and its impact on robotics applications – a review. Ind Robot 2005;32:268–81. [20] Dargahi J, Najarian S. Human tactile perception as a standard for artificial tactile sensing: a review. Int J Med Robotics Comput Assist Surg 2004;1(13):23–35.
[21] Signh H, Dargahi J, Sedaghati R. Experimental and finite element analysis of an endoscopic tooth-like tactile sensor. In: Second IEEE international conference on sensors. Toronto, Canada; 2003. [22] Dargahi J. An endoscopic and robotic tooth-like compliance and roughness tactile sensor. J Mech Design 2002;124:576–82. [23] Bar-Cohen Y, Mavroidisb C, Bouzit M, et al. Virtual reality robotic telesurgery simulations using MEMICA haptic system. In: Proceedings of the SPIE’s 8th annual international symposium on smart structures and materials. Newport; 2001. [24] Rao NP, Dargahi J, Kahrizi M, Prasad S. Design and fabrication of a microtactile sensor. In: Canadian conference on electrical and computer engineering towards a caring and human technology. Montreal, Canada; 2003. [25] Dargahi J. A study of the human hand as an ideal tactile sensor used in robotic and endoscopic applications. In: Proceedings of the CSME international conference. Montreal, Canada; 2001.
Contents lists available at ScienceDirect
Medical Hypotheses journal homepage: www.elsevier.com/locate/mehy
Can surgeon’s hand be replaced with a smart surgical instrument in esophagectomy? Siamak Hajizadeh Farkoush, Siamak Najarian * Artificial Tactile Sensing and Robotic Surgery Lab, Center of Excellence of Biomedical Engineering, Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
a r t i c l e
i n f o
Article history: Received 7 February 2009 Accepted 11 February 2009
s u m m a r y Esophageal cancer is the eighth most common cancer in the world. The most common surgical procedures for esophageal cancer are transhiatal esophagectomy and transthoracic esophagectomy. Thoracic esophagectomy involves an abdominal incision and a thoracotomy, but transhiatal esophagectomy involves both an abdominal incision and a cervical incision. It can reduce postoperative morbidities and fast recovery. In transhiatal esophagectomy, part of dissection is blind and lack of sufficient vision during operation increases the dangers of this kind of surgery. In this paper, we propose a hypothesis about replacing surgeon’s hand with surgical instrument in esophagectomy. The proposed instrument is one-forth of surgeon’s hand volume and it can surround the esophagus radially. So, it would be able to sheer and dissect all the adhesive tissues around the esophagus. For determining possible threshold of causing traumas in delicate tissues during esophagectomy, various tactile sensors can be incorporated into the surgical instrument to detect and control the contact force of the instrument with delicate biological structures. For evaluating the proposed hypothesis, we analyzed the function of the instrument with finite element method and finally we constructed an initial prototype of the designed instrument. Ó 2009 Elsevier Ltd. All rights reserved.
Introduction In the United States, the reported mean incidence of esophageal cancer in patients younger than 80 years is 3.2 per 100,000 persons, with an overall male-to-female ratio of 3:1 [1–3]. The incidence of esophageal cancer increases with age and the tumor occurs more often in African Americans than in whites [4,5]. The two predominant histological subtypes of esophageal cancer are adenocarcinoma and squamous cell carcinoma [6]. Once a tumor is identified and the histopathology is established, evaluation of the extent of invasion is necessary for staging and for selecting therapeutic options. This work-up includes computed tomography (CT) of the chest to exclude lung parenchyma or mediastinal involvement [7]. Treatment options include surgery, chemotherapy, and radiation therapy. These therapies can be used individually or, in some instances, together to improve outcomes. Treatment approaches depend on the location of the primary tumor, the disease stage, patient characteristics, and co-morbidities. Occasionally, histological subtypes also impact decisions regarding treatment [7–10]. Surgical resection of the esophagus for cancer is a technically demanding procedure. It usually involves removing part or all of the esophagus, part of the stomach, lymph nodes in the surround* Corresponding author. Tel.: +98 21 64542378; fax: +98 21 64542350. E-mail addresses: [email protected] (S.H. Farkoush), [email protected] (S. Najarian). 0306-9877/$ - see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.mehy.2009.02.045
ing area, and occasionally the spleen (if it is injured or bleeding). In the absence of widespread metastases, surgical resection of the esophagus for squamous cell and adenocarcinoma is preferred in most centers. The most common surgical procedures for esophageal cancer are transhiatal esophagectomy and transthoracic esophagectomy. Thoracic esophagectomy involves an abdominal incision and a thoracotomy, but transhiatal esophagectomy involves both an abdominal incision and a cervical (neck) incision, and the thoracic cavity is not opened [4,7,11]. During the 1970s, Orringer introduced the technique of transhiatal esophagectomy, which avoids thoracotomy [12]. In transhiatal esophagectomy, the abdominal component of the procedure involves complete mobilization of the stomach. Lymph nodes around the distal part of the esophagus, the gastric cardia, and the left gastric artery are resected in continuity with the specimen. The intrathoracic part of the esophagus is then dissected away from adjacent thoracic structures by using a blunt technique. To perform this maneuver, the surgeon opens the diaphragmatic hiatus and mobilizes the esophagus by careful manual dissection up into the thoracic cavity [4]. However, the use of an open approach has not clearly demonstrated the reduction of the risk of postoperative respiratory complications or postoperative mortality. In addition, part of the dissection is ‘‘blind” with the consequent risk of bleeding, particularly from the azygos vein, and damage to the trachea and bronchi. With the development of minimally invasive surgery, attempts were made to use alternative minimally invasive methods for
736
S.H. Farkoush, S. Najarian / Medical Hypotheses 73 (2009) 735–740
esophageal dissection [13–15]. However, combined methods using thoracoscopic dissection with conventional abdominal approaches have not achieved a significant reduction in respiratory morbidity, mostly due to the upper midline abdominal incision [11,16]. Considering that postoperative pulmonary complications are mainly caused by the prolonged deflation of the right lung during the operation and that midline abdominal and thoracic incisions compromise respiratory ability, scientists tried to avoid laparotomy and thoracotomy using the laparoscopic transhiatal approach. This approach could reduce postoperative morbidities and fast recovery [11]. Laparoscopic transhiatal esophagogastrectomy has many advantages. The estimated blood loss is minimal and it has no intraoperative complications. The operative time is shorter than in the other approaches. There are no intraoperative ventilation difficulties. The patients are ambulated early and there are no postoperative pulmonary complications. However, in spite of various advantages of Orringer technique in transhiatal esophagectomy, it has some limitations. In this technique, as shown in Fig. 1 [4], surgeon’s hand is entered in the patient’s thorax blindly. Hence, considering large size of the surgeon’s hand versus finite volume of thorax, and also, existence of some delicate biological structures in the thorax, such as aorta artery, lungs, airways, and trachea, transhiatal esophagectomy is a high risk operation. Lack of sufficient vision during operation increases the dangers of this kind of surgery. Additionally, in some cases that cancerous tissues are more adhesive, this type of surgery is more dangerous. For example, when there is high adhesion between tumoral tissue and aorta artery, surgeon may injure the aorta while dissecting
esophagus away from adjacent thoracic structures, and it may cause bleeding during and after the surgery. This is also true for lungs and other thoracic structures. In the Orringer technique, complete laparatomy is necessary. Considering various risks of this method and in order to decrease the size of abdominal incisions, some minimally invasive surgical approaches to esophagectomy have been reported. These involve laparoscopic and thoracoscopic techniques. In 2003, Horgan and colleagues reported their initial experience with a case of robotically assisted transhiatal esophagectomy [17]. In robotic systems, the vision is three-dimensional and surgical tools have movable wrists. So, performing a robotic endosurgery is easier than performing an endosurgery using handheld surgical tools. However, in both robotic and handheld models, it is easier to access the esophagus through upper part of the thorax cavity and dissect the tissues. But, as there is not enough vision and work space behind the esophagus, there is not enough safety even in performing a robotic surgery. In this paper, we propose a hypothesis about replacing surgeon’s hand with surgical instrument in esophagectomy. Hypothesis Our proposed hypothesis is about designing a surgical instrument which can be used in esophagectomy. The proposed instrument would be able to imitate surgeon’s hand movement for dissecting adhesive tissues and of course it would be smaller than surgeon’s hand. The proposed surgical instrument would be entered into the patient body through a 5 cm incision in the abdomen and so, as a result of minimizing the incisions in this concept, replacing surgeon’s hand with this surgical instrument in transhiatal esophagectomy can play a key role in improvement of transhiatal esophagectomy and converting this surgery to a minimally invasive surgery. In this hypothesis, we focus on designing a surgical instrument with fingers consisting of rotational joints which can sheer and dissect the tissue just like the surgeon’s fingers. For the better dominance in the thorax, it is also possible to equip the instrument with a handle as the substitute of the surgeon’s arm. Then the instrument can be inserted into thorax from the distal part of esophagus and it can go up to its proximal part to do the dissection process. As the instrument surrounds the esophagus completely and moves longitudinally along this organ, it can access entire surface of the esophagus. To have a more accurate control on the movement of the instrument head dynamic fingers, it is suggested to equip the instrument with a lever that can be controlled by the
Handle
The Instrument Head
Dynamic Fingers Fig. 1. Orringer technique in transhiatal esophagectomy [4].
Fig. 2. Different parts of the proposed instrument.
Lever
S.H. Farkoush, S. Najarian / Medical Hypotheses 73 (2009) 735–740
surgeon. Different parts of the designed instrument are shown in Fig. 2. The instrument head consisted of two parts, each part has five dynamic fingers. The two parts, firstly, are unhooked and turns into a hollow cylinder embedding esophagus by means of a locking mechanism (Fig. 3). So, the surgical instrument can surround the esophagus radially and dissect the adhesive tissues. In this case, the instrument is situated in the distal part of esophagus. The geometry and situation of the instrument’s fingers cause an ability to perform environmental dissection of the adhesive tissues, while going ahead. When the instrument reaches a sticky area, it sheers the tissue up to about 7 cm and dissects the probable adhesions. The way that the proposed instrument dissects the adhesive tissues is shown in Fig. 4.
737
force of tissues. These sensors can detect whether the surgical instrument apply forces beyond the allowed limit during the surgery and warn it to the surgeon. Considering some tactile sensors on the proposed instrument, possible threshold of causing traumas in delicate tissues during transhiatal esophagectomy can also be determined. Hence, the proposed instrument can be called a smart surgical instrument. Because of limitations of dimension, tactile sensors should be very small and so, we should use an array of FSR sensors on the fingers of the instrument. FSR sensors consist of a thin PVDF film that its electrical resistance reduces as a result of applying pressure. There is an approximately linear relationship between variations of electrical resistance of sensor and variations of applied forces. Therefore, the amount of force applied per unit area can be measured with acceptable accuracy.
Modifying the hypothesis by installing some tactile sensors Finite element analysis The artificial tactile sensing is a new method for obtaining the characteristics of a tumor in the soft tissue [18–20]. This includes detecting the presence or absence of a tumor or even mapping a complete tactile image [21–23]. Robotic minimally invasive surgery represents the most fascinating opportunities in the area of modern diagnostic and therapeutic possibilities in robotic surgery. The need to detect various tactile properties justifies the key role of tactile sensing which is currently missing in MIS [24]. With regard to artificial tactile sensing in medical robotics, the on-line measurement of variable contact forces that occurs during a robotic manipulator’s interaction with the biological tissue is of great importance [20]. This can be achieved by using various kinds of miniaturized sensors, most often mounted on the instrument. In spite of many advantages of MIS (such as, less pain, reduction of trauma, faster recovery time, smaller injuries, and post operation complications), it reduces the tactile sensory perception of the surgeon during grasping or manipulation of biological tissues [20,25]. The proposed surgical instrument will be in direct contact with delicate biological tissues and it is applicable in dissecting the adhesion of adjacent tissues, in esophageal surgery. Also, since the surgery is not open, it is necessary to provide the surgeon with suitable feedback, such as a sense of the amount of force exerted on the biological tissues. Therefore, the designed instrument can be equipped with tactile sensors capable of measuring contact
For evaluating the proposed hypothesis, we analyzed the function of the proposed instrument with finite element method. For finite element modeling of esophagus and the tissues around it, we attributed mechanical properties to each delicate tissue around esophagus such as aorta artery. So, by applying mechanical movement on these tissues, their possible traumas and injuries can be determined. Mechanical behavior of tissues during operating the surgical instrument on them is modeled as well. The achieved results can be used for preventing the risk of applying extra displacement on delicate tissues and decreasing their possible injuries. In fact, we can estimate the behavior of tissues as a result of motion of the instrument and the causing displacement in tissues and the amount of forces that in each moment is applied on the tissue by the instrument. So, the surgeon can prevent applying more pressure on the tissue before causing injury to it. In software modeling, we can determine the threshold of causing an injury in tissue. Hence, while the instrument is dissecting the tissues around the esophagus, a series of tactile sensors are needed to measure the amount of force which is applied on related tissues by the surgical instrument. By comparing the output data of tactile sensors with the results of software modeling, valid and low risk operation of the instrument can be guaranteed.
Fig. 3. Two parts of the proposed instrument head. The two parts firstly are unhooked and then turn into a hollow cylinder embedding esophagus by means of a locking mechanism.
738
S.H. Farkoush, S. Najarian / Medical Hypotheses 73 (2009) 735–740
Fig. 4. The way that the proposed instrument dissects the adhesive tissues.
For modeling the mechanical behavior of tissues in finite element method, mechanical properties of tissues are required. The mechanical properties can be determined through mechanical tests. Most of these tests would be performed to determine stress–strain curve. After determining the stress–strain curve, finite element model should be selected according to general characteristics of tissue. These models are mechanical models of tissues such as elastic model, hyperelastic model, and viscoelastic model. The finite element software that we used for analysis of our proposed instrument is ABAQUS. We considered elastic behavior for tissues. As there is high adhesion between tumoral tissue and aorta artery, surgeon may harm the aorta while dissecting esophagus away from adjacent thoracic structures, and it may cause bleeding during and after the surgery. Hence, we modeled the effect of the instrument on aorta while dissecting the adhesive tissues. For dissecting the tissues, the fingers of the designed instrument can be opened up to 7 cm and finite element analysis showed that this displacement will not cause any trauma in aorta artery. In
fact, we can estimate the behavior of aorta artery as a result of movement of instrument and the applied displacement. The amount of forces applied on the tissues is achieved from tactile sensors installed on the instrument. The amount of stresses caused in aorta artery, esophagus and the tumor is calculated in ABAQUS and its contour is shown in Fig. 5. Constructing an initial prototype for investigating the hypothesis For evaluating the proposed hypothesis and investigating how the instrument works, we constructed an initial prototype of it. The instrument has 10 fingers and each finger has a rotational joint. The fingers should have a synchronized radial motion. Head of instrument is made of two half-cylindrical parts and every part is linked to five fingers to each other by a locking mechanism and hence making a complete cylinder (as shown in Fig. 3). By using the locking mechanism, the instrument can surround the esophagus completely.
Fig. 5. Stress contour of aorta, calculated in ABAQUS.
S.H. Farkoush, S. Najarian / Medical Hypotheses 73 (2009) 735–740
739
Fig. 6. An initial prototype of the proposed instrument in different positions.
Diameter of the head of instrument is dynamic and can be changed easily as a result of radial motion of fingers. The dynamic diameter is 15–70 mm. The important specification of the proposed instrument is the way that it dissects the tissues. First, the instrument surrounds the esophagus and then locking mechanism makes the head of the instrument like the hallow cylinder. So, esophagus is positioned in the center of the cylindrical head. Surgeon controls the instrument while it is moving along the esophagus. In this stage, diameter of the dynamic head is about 20 mm. When instrument makes contact with adhesive tissues, rotational joint of fingers moves and diameter of head becomes about 70 mm. Because of this specification, the proposed instrument can dissect adhesive tissues away from esophagus. For actuating the rotational joints of the instrument, a lever should be used. This lever is controlled by the surgeon’s hand. In order to transfer the lever motion to fingers of the instrument, cable drive mechanism would be used. The prototype is made of medical grade steel and so it is biocompatible. Fig. 6 shows an initial prototype of the proposed instrument in different positions. Conclusion In this paper, we proposed a hypothesis about replacing surgeon’s hand with surgical instrument in transhiatal esophagectomy. The proposed instrument would be able to imitate surgeon’s hand movement for dissecting adhesive tissues. It would be entered into the patient body through a 5 cm incision in the abdomen and it surrounds the esophagus radially and sheers and dissects all the adhesive tissues around the tumor and esophagus. The instrument is small and one-forth of surgeon’s hand volume. For determining possible threshold of causing traumas in delicate tissues during esophagectomy, various tactile sensors can be incorporated into the surgical instrument to detect and control the contact force of the instrument with delicate biological tissues. For evaluating the proposed hypothesis, we analyzed the function of the instrument with
finite element method and we also constructed an initial prototype of the designed instrument to investigate how works. Acknowledgement We would like to express our gratitude to the Center of Excellence of Biomedical Engineering of Iran based in Amirkabir University of Technology, Faculty of Biomedical Engineering for its contribution. References [1] Fumoto S, Hiyama K, Tanimoto K, et al. EMP3 as a tumor suppressor gene for esophageal squamous cell carcinoma. Cancer Lett 2009;274:25–32. [2] Kamangar F, Dores GM, Anderson WF. Patterns of cancer incidence, mortality, and prevalence across five continents: defining priorities to reduce cancer disparities in different geographic regions of the world. J Clin Oncol 2006;24:2137–50. [3] Pickens A, Orringer MB. Geographical distribution and racial disparity in esophageal cancer. Ann Thorac Surg 2003;76:S1367–9. [4] Mackenzie DJ, Pepperell PK, Billingsley KG. Care of patients after esophagectomy. Crit Care Nurse 2004;24:16–31. [5] Quinn KL, Reedy A. Esophageal cancer: therapeutic approaches and nursing care. Semin Oncol Nurs 1999;15:17–25. [6] Toshiyuki Sakaeda T, Yamamori M, Kuwahara A, Nishiguchi K. Pharmacokinetics and pharmacogenomics in esophageal cancer chemoradiotherapy. Adv Drug Deliv Rev 2009;61(5):388–401. [7] Layke JC, Lopez P. Esophageal cancer: a review and update. Am Family Phys 2006;73:2187–94. [8] Jackson C, Starling N, Chua YJ, Cunningham D. Pharmacotherapy for oesophagogastric cancer. Drugs 2007;67:2539–56. [9] Siewert JR, Ott K. Are squamous and adenocarcinomas of the esophagus the same disease? Semin Radiat Oncol 2007;17:38–44. [10] Khushalani N. Cancer of the esophagus and stomach. Mayo Clin Proc 2008;83:712–22. [11] Dulucq JL, Wintringer P, Mahajna A. Totally laparoscopic trans-hiatal gastroesophagectomy for benign diseases of the esophago gastric junction. World J Gastroenterol 2007;13(2):285–8. [12] Orringer MB. Transhiatal esophagectomy without thoracotomy for carcinoma of the thoracic esophagus. Ann Surg 1984;200:282–8. [13] Cuschieri A. Thoracoscopic subtotal oesophagectomy. Endosc Surg Allied Technol 1994;2:21–5.
740
S.H. Farkoush, S. Najarian / Medical Hypotheses 73 (2009) 735–740
[14] Dexter SP, Martin IG, McMahon MJ. Radical thoracoscopic esophagectomy for cancer. Surg Endosc 1996;10:147–51. [15] Watson DI, Davies N, Jamieson GG. Totally endoscopic Ivor Lewis esophagectomy. Surg Endosc 1999;13:293–7. [16] McAnena OJ, Rogers J, Williams NS. Right thoracoscopically assisted oesophagectomy for cancer. Brit J Surg 1994;81:236–8. [17] Horgan S, Berger RA, Elli EF, Espat NJ. Robotic-assisted minimally invasive transhiatal esophagectomy. Am Surg 2003;69(7):624–6. [18] Galea AM. Mapping tactile imaging information: parameter estimation and deformable registration. Cambridge, MA: Harvard University; 2004. [19] Dargahi J, Najarian S. Advances in tactile sensors design/manufacturing and its impact on robotics applications – a review. Ind Robot 2005;32:268–81. [20] Dargahi J, Najarian S. Human tactile perception as a standard for artificial tactile sensing: a review. Int J Med Robotics Comput Assist Surg 2004;1(13):23–35.
[21] Signh H, Dargahi J, Sedaghati R. Experimental and finite element analysis of an endoscopic tooth-like tactile sensor. In: Second IEEE international conference on sensors. Toronto, Canada; 2003. [22] Dargahi J. An endoscopic and robotic tooth-like compliance and roughness tactile sensor. J Mech Design 2002;124:576–82. [23] Bar-Cohen Y, Mavroidisb C, Bouzit M, et al. Virtual reality robotic telesurgery simulations using MEMICA haptic system. In: Proceedings of the SPIE’s 8th annual international symposium on smart structures and materials. Newport; 2001. [24] Rao NP, Dargahi J, Kahrizi M, Prasad S. Design and fabrication of a microtactile sensor. In: Canadian conference on electrical and computer engineering towards a caring and human technology. Montreal, Canada; 2003. [25] Dargahi J. A study of the human hand as an ideal tactile sensor used in robotic and endoscopic applications. In: Proceedings of the CSME international conference. Montreal, Canada; 2001.