MIS posterior short segment fixation with Schanz pins

B1 injuries indicate monosegmental pure osseous failure of the posterior tension band. They are also called "Chance" fractures. The vertebral body and the posterior tension band have failed in flexion distraction mode through the bony structures.

MIS reduces the surgical trauma for the patient, potentially resulting in a quicker recovery while providing similar clinical mid to long term results.

More details on repair of dural laceration can be found here.

Percutaneous posterior approach for pedicle screw placement is used together with the appropriate patient preparation.

Primary reduction is performed by positioning of the patient onto a frame to create lordosis.

Due to the fact that bilateral instrumentation is necessary in all cases, all steps described below are repeated on the opposite side, unless described otherwise.

In the thoracic spine, multisegmental stabilization is necessary in general.

If this is the case, pedicle screws have to be used instead of Schanz pins.

Rarely, in patients with significant kyphosis, PSSF-SS can be used to achieve better fracture reduction and lordosis.

Schanz pins are inserted into the vertebrae cephalad and caudal to the fracture level on both sides, using the starting point and trajectory as described in pedicle screws. ( Schanz pin insertion)

The fracture clamps are placed on the proximal and distal Schanz pins.

The rod is inserted through both the clamps and the whole construct is pushed towards the spine.

The distance between the two Schanz pins is secured by tightening the rod to the fracture clamps.

The kyphosis is corrected using the Schanz pins restoring the normal lordosis.

The lordotic correction may be applied immediately when there is no posterior wall fragment.

The angle of the Schanz pins is fixed by tightening the Schanz pins to the fracture clamps.

The distance between the two Schanz pins is secured by tightening the rod to the fracture clamps.

When reduction is achieved, the Schanz pins are cut.

The final construct is shown from a lateral view.

Although fusion was routinely performed for all spinal fractures, its indications are now being restricted to fractures that are highly unstable.

Nonfusion fixations can be performed for A3, A4, and B1 type injuries.
Fusion is routinely performed for A2, B2, B3, and all C injuries as they are unstable injuries with extensive soft tissue and ligamentous disruption.

For nonfusion surgeries, the facet joint capsule is preserved during the entire procedure.

The screws can be removed after 9 months once the fracture has healed.

Prior to wound closure, intraoperative imaging is performed to check the adequacy of reduction, position, and length of pins and the overall coronal and sagittal spinal alignment.

Patients are made to sit up in the bed on the first day after surgery. Bracing is optional. Patients with intact neurological status are made to stand and walk on the second day after surgery. Patients can be discharged when medically stable or sent to a rehabilitation center if further care is necessary. This depends on the comfort levels and presence of other associated injuries.

Patients are generally followed with periodical x-rays at 6 weeks, 3 months, 6 months, and 1 year. Normally, 5-10 degrees of loss of kyphosis can be observed within the first 6 months, which does not affect the functional outcomes. For nonfusion surgeries, the implants can be removed once fusion is confirmed.