Surgery – Specula – Retractor
Reexamination Certificate
1998-10-28
2001-05-08
Mancene, Gene (Department: 3732)
Surgery
Specula
Retractor
C600S207000, C600S153000, C604S164030, C606S185000, C606S198000
Reexamination Certificate
active
06228022
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to methods and instruments for performing spinal surgery. Specifically, the invention concerns laparoscopic techniques and instruments to prepare a disc space for a vertebral implant.
The use of surgical techniques to correct the causes of low back pain, such as spinal injuries and deformities, has steadily increased over the last several years. One common procedure for relieving pain from the above-described problems is a discectomy, or surgical removal of a portion or all of an intervertebral disc, followed by implantation of a device between the adjacent vertebrae, such as a vertebral implant or fusion device. Typically, implantation of such a device is intended to promote bony fusion between the adjacent vertebral bodies.
Various surgical methods have been devised for implantation of devices into a subject disc space. For example, PCT International Publication No. WO 97/30666 to Zdeblick et al. discloses laparoscopic surgical techniques and instruments for preparing a disc space for implantation of fusion devices or implants. The laparoscopic instrumentation provides a sealed working channel to the disc space through which the disc space is distracted, the vertebral endplates and surrounding discs are reamed, and the vertebral implant inserted, all under direct vision through a laparoscopic port engaged to the end of the sleeve. In this technique, a single sleeve is alternately placed at bilateral locations on the disc space through a single incision in the skin for insertion of a pair of fusion devices or vertebral implants at each location. A switching sleeve extends through the outer sleeve of the laparoscope to protect the tissue at the surgical site as the outer sleeve of the laparoscope is moved between bilateral locations. In order to move the outer sleeve, the switching sleeve is inserted and then the distractor fingers of the outer sleeve are withdrawn from the disc space at the first bilateral location. T he outer sleeve and the switching sleeve are then manipulated through the skin to the second bilateral location. The techniques and instruments of the '666 publication suffer from the disadvantage of requiring multiple manipulations of vessels and tissue adjacent the vertebral bodies to perform the procedure. Multiple manipulation of the vessels and tissues may increase the overall time of the procedure and increase the risk of damage to the vessels.
While the above described technique represents a significant advance over prior surgical procedures for preparation and insertion of a fusion devices or other implants in the disc space, a need for improvement remains. In particular, procedures and instruments are required that minimize trauma to tissue surrounding the surgical site while allowing bilateral implantation of fusion devices in the disc space. The present invention is directed to these needs, among others, in the field.
SUMMARY OF THE INVENTION
An apparatus for distracting a disc space is provided in accordance with one aspect of the invention. The apparatus includes a switching sleeve having a first end and an opposite second end. The sleeve defines a pair of distractor channels and a locking channel between said pair of distractor channels extending between the first and second ends. Preferably, a pair of distractors are rotatably received within a corresponding one of the distractor channels. Each of the distractors have a head extending from the first end, an engagement portion proximate the second end, and a stem extending between the head and the engagement portion. The locking channel is configured to receive a locking mechanism to lock the heads in an insertion position for insertion into the dilated disc space. The locking mechanism is movable after the heads are inserted into the disc space to release the heads for rotation to a second position to distract the disc space. Preferably, an outer sleeve is disposed about the switching sleeve and is selectively locked thereto.
In accordance with another aspect of the invention, an apparatus for use in preparing a disc space for insertion of a vertebral implant is provided. The apparatus includes an outer sleeve with a first end having a pair of opposite fingers extending therefrom and an opposite second end having a coupling mechanism. The outer sleeve defines a passage extending between the first end and the second end. A switching sleeve is removably disposed within the passage. Preferably, the switching sleeve has a pair of distractors at a first end. More preferably, each of the distractors is rotatable from an insertion position to a distraction position. Optionally, the switching sleeve may be configured with a slot at a second end configured to releasably receive the coupling mechanism and couple the outer sleeve to the switching sleeve. In one embodiment, the apparatus includes a locking mechanism disposed between the pair of distractors to maintain the distractors in their insertion position. In another embodiment, the passage of the apparatus is configured to allow bilateral implantation of a pair of spinal implants into the disc space. In one form, the passage of the outer sleeve includes a first portion and a second portion, the first portion defining a first center and the second portion defining a second center, the first center spaced a distance d from the second center. In another form, the first portion defines a first circular area having a radius R
1
and the second portion defines a second circular area having a radius R
2
. In still a further form, the first circular portion overlaps the second circular portion.
In yet another aspect of the present invention, an apparatus for distracting a disc space and allowing insertion of spinal implants therethrough is provided. The apparatus includes a sleeve having a first end and an opposite second end and a pair of opposite fingers extending from the first end. The sleeve defines a single channel therethrough. The channel includes a first portion and an adjacent second portion each configured to receive a spinal implant for bilateral insertion into the disc space. A sealing member sealingly engages the sleeve at the second end and has at least one bore for sealingly receiving surgical instruments therethrough. The at least one bore is substantially aligned with a corresponding one of the implant insertion portions.
In another aspect of the present invention, a method for preparing a disc space of a patient for implantation of a device between adjacent vertebrae is provided. The method includes the steps of gaining access to the disc space; providing a sleeve assembly including an outer sleeve having a first end and an opposite second end, the outer sleeve defining a passage between the first end and the second end, a switching sleeve disposed within the passage and coupled to the outer sleeve at a second end, the switching sleeve having a locking channel between a pair of opposite distractors extending through the switching sleeve. The sleeve assembly is advanced into the patient until the first end of the sleeve assembly is positioned adjacent the disc space. The sleeve assembly is impacted to insert the distractors into the disc space. Preferably, the distractors are rotatable and are rotated to further distract the disc space. In one more aspect of the method, a guide member is disposed in the disc space and the sleeve assembly is advanced over the guide member to the disc space.
One object of the present invention is to provide surgical techniques and instruments that permit preparation of a disc space for bilateral insertion of a fusion device or vertebral implant with minimal disruption of tissue surrounding the surgical site. A further object of the invention is to enhance the use of laparoscopic techniques with bilateral insertion of vertebral implants.
Other objects and benefits can be discerned from the following written description and the accompanying figures.
REFERENCES:
patent: 3750667 (1973-08-01), Pshenichny et al.
patent: 4545374 (1985-10-01),
Friesem Tai
Josse Loic
Liu Mingyan
Mancene Gene
Philogene Pedro
SDGI Holdings Inc.
Woodard Emhardt Naughton Moriarty & McNett
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