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THE SCREWLESS PROCEDURE


Chronic back pain is something many people live with each day. It affects both men and women equally and is the leading cause of disability in people under 45 years old. It can make simpler routines seem like impossible feats and have a substantial impact on everyday life. Twenty-eight percent of adults with lower back pain report limited activity due to a chronic condition.

 

Pedicle screw fixation has been the most widely used method of stabilization, however there has been an increase in the use of ISP devices as a less invasive alternative. ISP devices are positioned between the spinous processes versus pedicle screws which are drilled into the pedicles of the vertebrae in order to act as anchor points for connection of additional rods and other hardware.  Minimally invasive ISP devices have been shown to preserve normal anatomy and have resulted in shorter surgery times, less pain and faster healing times when compared to pedicle screw procedures.


The ZIP device is the strongest interspinous fusion device I have seen in my career”... “The articulating spikes adapt nicely to the anatomy and the one-step locking mechanism makes the fixation very easy. It’s a true screwless procedure.
— Dr. Steffen Haug, Head of the Spine Department of the German Orthopedic Hospital in Bahrain

 

A study on 32 patients (21 ISP and 11 bilateral PS) from Wang et al. found that the ISP plate is not only easy to implant but is also associated with minimal operative risk.[1] Compared with bilateral PS/rod constructs, the ISP plate fixation lead to less EBL and shorter operative time, without an increase in the rate of pseudarthrosis. Hospital length of stay (LOS) was also shorter, which aligned well with the goals of minimal access spinal technologies.[1]

Clinical outcome in the interspinous fusion device group and pedicle screw group after surgery for EBL, OP time and LOS. EBL: estimated blood loss, OP time: duration of the operation, LOS: length of hospital stay.

Clinical outcome in the interspinous fusion device group and pedicle screw group after surgery for EBL, OP time and LOS.

EBL: estimated blood loss, OP time: duration of the operation, LOS: length of hospital stay.

Fusion success outcome: ISP-Grade 1 indicates small islands of bone; Grade 2 shows larger islands of coalescence with bringing to the surrounding anatomy; Grade 3 indicates some solid incorporation and obvious stability and maturity; Classification of interbody fusion success was based on the BSF scale by Brantigan, Steffee, and Fraser (SPINE 1993;18:2106-7)

Fusion success outcome: ISP-Grade 1 indicates small islands of bone; Grade 2 shows larger islands of coalescence with bringing to the surrounding anatomy; Grade 3 indicates some solid incorporation and obvious stability and maturity; Classification of interbody fusion success was based on the BSF scale by Brantigan, Steffee, and Fraser (SPINE 1993;18:2106-7)

 

Vokshoor et al. observed that 91% (41 of 45) of levels treated with lumbar interbody fusion supplemented by an interspinous fixation device demonstrated solid bridging bone on 2 year post-operative CT imaging.[2] Similarly, Kim et al. showed comparable fusion rates between the patient in the ISP (92.5%) and PS group (91.6%).[3]

 

ISP and pedicle screw groups had comparable improvement in Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) score outcome scores at 1 year after surgery. However, ISP patients had immediately after ISP procedure more improved VAS score (4.6+/-3.7) than the pedicle screw group (7.0+/-3.5) with the difference being statistically significant (p<0.05).[2,3]

Clinical outcome in the interspinous fusion device group and pedicle screw group on year after surgery (p<0.05) for VAS and KDI.  Preop: preoperation, Postop: postoperation, ISP: interspinous fusion device.

Clinical outcome in the interspinous fusion device group and pedicle screw group on year after surgery (p<0.05) for VAS and KDI. 

Preop: preoperation, Postop: postoperation, ISP: interspinous fusion device.


 
 

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