Surgery – Instruments – Blunt dissectors
Reexamination Certificate
1997-03-18
2002-03-26
Dawson, Glenn K. (Department: 3761)
Surgery
Instruments
Blunt dissectors
C600S207000, C604S103140
Reexamination Certificate
active
06361543
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to the field of inflatable tissue separation devices and methods of using such devices. The apparatus and methods of the present invention may be used in any procedure requiring dissection and/or retraction of tissue planes throughout the body including inguinal hernia repair, pelvic lymphadenectomy and bladder neck suspension in the preperitoneal space; renal, adrenal, aortic and anterior spinal access in the retroperitoneal space; penile prosthetic reservoir placement in the anterior abdominal wall; and augmentation mammaplasty prosthetic placement. By way of example only, use of such devices and methods for hernia repair will be described.
A hernia is the protrusion of part of a body part or structure through a defect in the wall of a surrounding structure. Most commonly, a hernia is the protrusion of part of abdominal contents, including bowel, through a tear or weakness in the abdominal wall, or through the inguinal canal into the scrotum.
An abdominal hernia is repaired by suturing or stapling a mesh patch over the site of the tear or weakness. The mesh patch has a rough surface that can irritate the bowel and cause adhesions. It is therefore preferred to install the patch properitoneally. It is intended that the terms properitoneal and preperitoneal be synonymous. The mesh patch is preferably attached to the properitoneal fascia of the abdominal wall, and covered by the peritoneum. To attach the mesh patch to the properitoneal fascia, the peritoneum must be dissected from the properitoneal fascia. This is a difficult process which involves the risk of puncturing the peritoneum. Moreover, strands of properitoneal fat interconnecting the peritoneum and the properitoneal fascia make it difficult to see the site of the hernia.
The use of laparoscopic techniques to perform hernia repair is becoming increasingly common. In the conventional procedure for carrying out a hernia repair laparoscopically, an endoscope and instruments are introduced into the belly through one or more incisions in the abdominal wall, and are advanced through the belly to the site of the hernia. Then, working from inside the belly, a long incision is made in the peritoneum covering the site of the hernia. Part of the peritoneum is dissected from the properitoneal fat layer to provide access to the fat layer. This is conventionally done by blunt dissection, such as by sweeping a rigid probe under the peritoneum. In this procedure, it is difficult to dissect the peritoneum cleanly since patchy layers of properitoneal fat tend to adhere to the peritoneum.
In an alternative known laparoscopic hernia repair procedure, the belly is insufflated. An incision is made in the abdominal wall close to the site of the hernia. The incision is made through the abdominal wall as far as the properitoneal fat layer. The peritoneum is then blunt dissected from the properitoneal fat layer by passing a finger or a rigid probe through the incision and sweeping the finger or rigid probe under the peritoneum. After the peritoneum is dissected from the properitoneal fat layer, the space between the peritoneum and the properitoneal fat layer is insufflated to provide a working space in which to apply the mesh patch to the properitoneal fascia.
During the blunt dissection process, it is easy to puncture through the peritoneum, which is quite thin. Additionally, after initial dissection of the properitoneal space, known surgical procedures require introduction of various instruments in the space to conduct the surgery. These instruments can cause inadvertent puncture of the peritoneum wall after the initial dissection. A puncture destroys the ability of the space between the peritoneum and the fascia to hold gas insufflation; pressurized gas can travel through a puncture in the peritoneum to allow the fluid to migrate to the abdominal cavity and degrade the pressure differential maintaining the properitoneal cavity. Also, it is difficult to dissect the peritoneum cleanly since patchy layers of properitoneal fat tend to adhere to the peritoneum. Clearing difficult adhesions can sometimes result in a breach of the peritoneum itself.
U.S. Pat. No. 5,309,896, of which this application is a Continuation-in-Part, discloses a laparoscopic hernia repair technique that enables a mesh patch to be attached to the properitoneal fascia without breaching the peritoneum. An incision is made through the abdominal wall as far as the properitoneal fat layer. A multi-chambered inflatable retraction device is pushed through the incision into contact with the peritoneum, and is used to separate the peritoneum from the underlying layers. The main end chamber of the inflatable retraction device is then inflated to elongate the inflatable retraction device towards the site of the hernia. As it inflates, the inflatable retraction device gently separates the peritoneum from the underlying layers. Once the main chamber of the inflatable retraction device is fully inflated, a second inflatable chamber is inflated. The second inflatable chamber enables the inflatable retraction device to continue to separate the peritoneum from the underlying layers after the main inflatable chamber has been deflated.
One or more apertures are then cut in the envelope of the main inflatable chamber to provide access to the site of the hernia for instruments passed into the main chamber. With such an arrangement, instruments pass through the main chamber situated between the peritoneum and the underlying layers. In this way, a patch can be attached to the properitoneal fascia without breaching the peritoneum.
Another device for separating tissue layers is disclosed in U.S. patent application Ser. No. 07/911,714, of which this application is a continuation-in-part. The apparatus includes a main envelope that defines a main inflatable chamber. The apparatus also includes an introducing device for introducing the main envelope in a collapsed state between the first layer of tissue and the second layer of tissue. The introducing device inflates the main envelope into an expanded state to separate the first layer of tissue from the second layer of tissue, and to create a working space between the first layer of tissue and the second layer of tissue. Finally, the apparatus includes an insufflating device for introducing insufflation gas into the working space between the first layer of tissue and the second layer of tissue.
In a method according to U.S. patent application Ser. No. 07/911,714 of separating a first layer of tissue from a second layer of tissue, a main envelope and insufflation gas are provided. The main envelope defines a main inflatable chamber. The main envelope is introduced in a collapsed state between the first layer of tissue and the second layer of tissue. The main envelope is inflated into an expanded state to separate the first layer of tissue from the second layer of tissue, and to create a working space between the first layer of tissue and the second layer of tissue. Finally, insufflation gas is introduced into the working space between the first layer of tissue and the second layer of tissue.
In a first practical embodiment of an apparatus according to U.S. patent application Ser. No. 07/911,714, the main envelope and the introducing device constitute a first component that separates the first layer of tissue from the second layer of tissue to create the working space. The insufflation device constitutes a second component, which insufflates the working space to maintain the separation of the first layer of tissue from the second. The insufflation device is tubular, has an anchor flange slidably mounted on it, and has a toroidal inflatable chamber at its distal end. The anchor flange and toroidal inflatable chamber together form a gas-tight seal with the second layer of tissue.
In a method according to U.S. patent application Ser. No. 07/911,714 of using the two-component apparatus, the introducing device is used to push the main envelope in a collapsed state through an incision through the secon
Chin Albert K.
Lunsford John P.
Moll Frederic H.
Smith Jeffrey A.
Dawson Glenn K.
Sherwood Services AG
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