Expedium Verse System

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Expedium Verse System

Philip Horsting, Jean Ouellet

The Expedium Verse pedicle screw system (Fig 1 below) combines the attributes of multiple screw types (side-loading, monoaxial, polyaxial, uniplanar, and reduction screws) while offering intraoperative flexibility allowing surgical staff to address unplanned circumstances with one versatile implant. This ultimately results in the delivery of a more predictable intraoperative experience for the treatment of both adult and paediatric spine deformity.

The Expedium Verse implant incorporates technology that allows for converting the polyaxial screw into a monoaxial screw while allowing for translation along the rod. The correction key is used as a locking mechanism that provides independent locking of polyaxial head and rod.

Details
Instruments
Clinical Cases
Videos
Disclaimer

The "hypermobility" or increased angulation (Table 1) of the polyaxial head in combination with the reduction tabs simplify rod capture while providing a powerful threaded reduction mechanism that accommodates controlled approximation of the spine to the rod. The pedicle screws serve as a powerful instrument in the facilitation of correction maneuvers.

The result is a great reduction in the number of instruments required for fusion procedures, potentially simplifying the surgical instrument table and reducing the costs associated with the sterilization process. The Expedium Verse pedicle screw can be converted into a monoaxial implant while allowing the screw to articulate around the rod. Tighten the poly lock of the correction key with the torque limiting handle while applying counter torque to lock the polyaxial head (Fig 2).

Fig 1 Expedium Verse polyaxial pedicle screw with system features.

Table 1 Screw angular range of motion.

Fig 2 Instruments. Correction key (a), unitized set screw (b), torque limiting handle (c).

Instrument design and set configuration

Through the redesign and feature enhancement on both the instruments and implants, it was possible to significantly reduce the number of instruments when compared to a traditional system such as the Expedium 5.5, enabling a shift away from instrument based correction methods to a more implant based procedure.

The polyaxial screwdriver modular design also allows for intraoperative assembly and includes tissue protection sleeves (Fig 3).

The Expedium Verse system provides a flex clip reducer (Fig 4) known from the Expedium 5.5 system for surgeons in case a reduction tab is accidentally or intentionally removed prior to reducing the rod into the screw head.

A tab remover has been provided for removal of the Expedium Verse screw reduction tabs at the completion of the procedure (Fig 5).

Please refer to Expedium Verse IFU for complete listing of warnings, contraindications and precautions.

Fig 3 Polyaxial screw driver.

Fig 4 Flex clip reducer.

Fig 5 Tab breaker.

Cases provided by Philip Horsting, Nijmegen, Netherlands

Case 1: Teenage boy with intellectual disability

Twelve months prior to his first visit to our clinic, the father of this 17-year-old intellectually disabled boy found a scoliosis, later confirmed by his therapist.
The patient was physically grown comparable to his age but mentally functioned at a 2-year-old level. No syndromic diagnosis was made after visits to a pediatrician. He had been diagnosed with severe autism. Behavioural changes might be suggestive of pain. The patient was unable to specifically indicate pain or (progressive) limitations.

On physical examination a cooperative boy was seen, normal build and height, normal to high paraspinal muscle tone. Standing upright he was off balance to the right. Neurological examination showed absent abdominal skin reflexes bilaterally. The curve was classified as neuromuscular type scoliosis (Fig 6). Due to the curve magnitude, being off balance, and with (severely) limited nonoperative options (Fig 7), surgical treatment was discussed with the family.

He was scheduled for a posterior deformity correction from T4L3. Under general anesthesia, with IONM (TC-MEP) the deformity was corrected. Intraoperatively, an epidural catheter was placed with the tip at T7 for postoperative analgesia.

Mobilisation started the day after surgery. He was discharged the fourth day after surgery. He returned for scheduled follow-up after 7 weeks (Fig 8). He seemed less agitated compared to the period before surgery. He did not seem to have specific limitations.

Fig 6ab Preoperative clinical pictures, posterior upright (a) and forward bending (b).

Fig 7a-c Preoperative radiographs: FS AP, FS lateral, and sidebending (noncompliant due to his mental abilities).

Fig8a-b Postoperative radiographs: FS AP, FS lateral (sitting).

Case 2: 17-year-old female patient

The patient was known and under orthopedic control for a Lenke 5C-type AIS since 2009. Initial treatment with a Boston Brace failed to halt progressive growth, and curve progression became apparent beyond surgical treatment threshold (Fig 9). Bending FS showed TL correction 58 -> 30 (plm 50%). MT correction 43 -> 16 (plm 35%) (Fig 10). The patient was referred to our hospitalfor logistics regarding surgical planning.

After her visit to our clinic, she was planned for surgical correction of the deformity from T5L4 (Fig 11). Surgical procedure with IONM (TC-MEP) postoperative epidural analgesia with the catheter tip at T8. She was mobilised the first postoperative day (Fig 12) and discharged the fourth day after surgery. The patient returned for her 6-month follow-up without any complaints. Limitations are in line with our advice (no sports for 6 months postoperatively). She has no pain and uses no medication.

Fig 9ab Preoperative conventional imaging: posterior view upright and forward bending.

Fig 10a-b Preoperative imaging: FS AP and FS lateral.

Fig 12a-b Postoperative images: FS AP and FS lateral.

Fig 11a-h Intraoperative imaging. Modular screw driver with ratchet. Multifunctional screw head extension tube with locking mechanism and anti-torque T-handle (one instrument for innie insertion, vertebral body derotation, and final tightening innie torque tightening).

A novel implant-based solution to spinal deformity correction

Presentation delivered by Jean Ouellet (Canada) providing an overview of the core principles of spinal deformity correction.

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