Operating Technique – Diametros Med

Operating System

Patient positioning:

The Lobster® device is intended to stop the segmental extension and to distract the interspinous space between the lumbar spine vertebrae (L1-L5), maintaining the foraminal height, opening up the area of the spinal canal, reducing stress on the facet joints and relieving pressure on the posterior annulus of the intervertebral disc.

Lobster® is implanted through a minimally invasive surgical technique with a specific and dedicated instruments set.
The device consists of a fusiform body with a central saddle, and 4 “wings” that open and close, located at the end of the central body.
The central saddle is designed to be inserted between the two vertebral spinous processes, object of distraction, while long “wings”, opened after the implant placement, prevent ventral and lateral migration of the device.

Percutaneous lateral surgical approach. Stabilizing anatomical structures are preserved:

Supraspinous ligament is left intact.
Interspinous ligament in only pierced to the size of the implant.
No bone needs to be trimmed to facilitate the insertion of the implant.

Guide wire introduction:

Under lateral fluoroscopy, carefully advance the guide wire between the spinous processes, keeping it parallel to the coronal plane and centered between the two spinous processes until it reaches the interspinous ligament, which gives a slightly increased resistance.

Interspinous ligament perforation:

Insert the instrument just assembled on the guide wire to reach and pierce the interspinous ligament.

Remove the dilatation tube 01 (LOB-0201) and the dilatation tube 02 (LOB-0202).

Then remove the guide wire and the handle.

Dilatation tubes insertion:

Insert on the dilatation tube 01 (LOB-0201) the dilatation tube 02 (LOB-0202) and the dilatation tube 03 (LOB-0203), then proceed removing the first two ones to implant Lobster size 8/10/12. Do the same procedure with the dilatation tubes 04 (LOB-0204) to implant Lobster size 14. To implant the size 16, also use the dilatation tube 05 (LOB-0205).

Make sure that the “insert” mark on the dilatation tube 03 is facing upwards.

Then remove the guide wire and the handle.

To insert the tines of the dilatation tube 3 through the spinous processes, it is possible to hammer with the batting support (LOB-0108).

Remove the dilatation tube 01 (LOB-0201) and the dilatation tube 02 (LOB-0202).

Implant size selection:

Choose the implant size with the probes starting from the smallest size (LOB-0308 – yellow handle) and insert it into the dilatation tube 03, gently pushing the trial implant through the ligament between the two spinous processes.

If the size of the first trial implant is not suited, remove the trial implant and insert into the dilatation tube the size of the next trial, repeating the process until reaching the most suitable for the patient. Once the implant measurement is selected, remove the probe.

Open the packaging:

After establishing the correct size, open the sterile implant package chosen, selecting it among the 2 available versions :
Lobster – Titanium / LBT
Lobster – Titanium-Peek / LBS

Holder and Implant assembly:

1. Place the sterile implant on the holder (LOB-0101).

2. Insert the opening tube for implant holder (LOB-0102) into the implant holder (LOB-0101), firmly holding the implant with a hand. This handle, turning counterclockwise, opens the fins of the Lobster; vice versa, turning it clockwise, it closes the fins.

3. Insert the shaft for fixing implant holder (LOB-0103) into the Lobster opening tube; doing this the thread on the rod is in contact with the implant cochlea. Screw the rod for attachment clockwise, while firmly holding the implant, until reaching the complete fixing of the Lobster to the support.

4. Before implanting the device, do a preliminary check by opening and closing it.

Implant introduction:

Insert the device through the dilatation tube, making sure that the marker “insert” on the holder is facing upwards.

Check with the fluoroscope that the implant saddle reaches the spinous processes, then rotates the whole Holder system 90 degrees (left or right is the same). If the “open” mark on the holder is facing up, the device is in the correct position to open.

Once the implant is correctly positioned in the center between the spinous processes:

Retract the dilatation tube 3 and begin the process of gradual and simultaneous opening of the fins, to fix the device. Rotate counter-clockwise the opening tube (LOB-0102) to open the device, until the device opens completely. The fins lock automatically when they reach their maximum opening, not going over. Do not force them further.

Implant release and end of the intervention:

Before removing the instruments, control under fluoroscopy that the device is correctly opened in the selected position.
Turn counterclockwise the fixing shaft (LOB-0103) to remove the thread on the rod from the device; retract of 3 cm.
Retract the tube opening for implant holder (LOB-0102) of 3 cm taking care not to rotate it, and then retract the implant holder (LOB-0101).
Extract the dilation tube and suture the entrance hole.

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