Hybrid lateral mass screw sublaminar wire construct: A salvage technique for posterior cervical fixation in pediatric spine surgery

Postoperative Spinal CT: What the Radiologist Needs to Know

During the past 2 decades, the number of spinal surgeries performed annually has been steadily increasing, and these procedures are being accompanied by a growing number of postoperative imaging studies to interpret. CT is accurate for identifying the location and integrity of implants, assessing the success of decompression and intervertebral arthrodesis procedures, and detecting and characterizing related complications. Although postoperative spinal CT is often limited owing to artifacts caused by metallic implants, parameter optimization and advanced metal artifact reduction techniques, including iterative reconstruction and monoenergetic extrapolation methods, can be used to reduce metal artifact severity and improve image quality substantially. Commonly used and recently available spinal implants and prostheses include screws and wires, static and extendable rods, bone grafts and biologic materials, interbody cages, and intervertebral disk prostheses. CT assessment and the spectrum of complications that can occur after spinal surgery and intervertebral arthroplasty include those related to the position and integrity of implants and prostheses, adjacent segment degeneration, collections, fistulas, pseudomeningoceles, cerebrospinal fluid leaks, and surgical site infections. Knowledge of the numerous spinal surgery techniques and devices aids in differentiating expected postoperative findings from complications. The various types of spinal surgery instrumentation and commonly used spinal implants are reviewed. The authors also describe and illustrate normal postoperative spine findings, signs of successful surgery, and the broad spectrum of postoperative complications that can aid radiologists in generating reports that address issues that the surgeon needs to know for optimal patient management.^©RSNA, 2019.

Nonmetallic posterior monosegmental cervical fusion of a dislocated C6/7 fracture in a 4-year-old girl : A case report

PURPOSE

Pediatric cervical spine injuries constitute approximately 1-2% of all pediatric trauma cases. Usually pediatric vertebral injuries appear as stable A type fractures, whereas B and C type injuries are relatively uncommon. In contrast to adults, the appropriate treatment strategy in children is still controversial and places spine surgeons in complex situations. This article reports the case of a 4-year-old girl with an unstable B type injury at the C6/7 level (AOSpine C6-7: B2 [F4 BL, C7:A1]) with bilateral locked fractures of the facet joints after falling down a flight of stairs.

PATIENT AND METHODS

Magnetic resonance imaging (MRI) and computed tomography (CT) were initially performed. The 4‑year-old girl was treated under intraoperative neurophysiological monitoring via open reduction after partial resection of both C7 upper articular processes and nonmetallic monosegmental posterior interlaminar fusion (FiberWire®) at the C6/7 level with temporary immobilization in a halo brace.

RESULTS

Clinical and radiological follow-up was carried out after 9 months. The patient suffered no pain or neurological deficits. Plain radiographs revealed a correct cervical alignment with anatomical correction of the initial dislocation.

CONCLUSION

The treatment of highly unstable pediatric B type injuries of the lower cervical spine via open reduction and nonmetallic monosegmental posterior interlaminar fusion results in good clinical and radiological outcomes. A temporary immobilization in a halo brace provides stability until osseous fusion occurs.

Treatment of chronic bilateral facet dislocation in a 6-year-old: A case report

Objectives:

Spine injuries seldom affect the subaxial spine in children less than 9 years of age. We describe the management of a chronic paediatric bilateral facet dislocation.

Methods:

Case report and literature review. A 6-year-old boy presented 10 weeks after a motor vehicle collision with bilateral C4–C5 malunited facet dislocation. He had an incomplete spinal cord injury; right brown sequard hemiplegia, Frankel grade D.

Results:

Surgical management was through posterior–anterior–posterior approach without preoperative skull traction. Two years postoperatively, the child was asymptomatic, ambulating and functioning well. The injury had healed in radiographs.

Conclusion:

A combined approach for chronic bilateral facet dislocation applies to the paediatric age group to realign the spine.

Spinal instrumentation in infants, children, and adolescents: a review

OBJECTIVEThe evolution of pediatric spinal instrumentation has progressed in the last 70 years since the popularization of the Harrington rod showing the feasibility of placing spinal instrumentation into the pediatric spine. Although lacking in pediatric-specific spinal instrumentation, when possible, adult instrumentation techniques and tools have been adapted for the pediatric spine. A new generation of pediatric neurosurgeons with interest in complex spine disorder has pushed the field forward, while keeping the special nuances of the growing immature spine in mind. The authors sought to review their own experience with various types of spinal instrumentation in the pediatric spine and document the state of the art for pediatric spine surgery.METHODSThe authors retrospectively reviewed patients in their practice who underwent complex spine surgery. Patient demographics, operative data, and perioperative complications were recorded. At the same time, the authors surveyed the literature for spinal instrumentation techniques that have been utilized in the pediatric spine. The authors chronicle the past and present of pediatric spinal instrumentation, and speculate about its future.RESULTSThe medical records of the first 361 patients who underwent 384 procedures involving spinal instrumentation from July 1, 2007, to May 31, 2018, were analyzed. The mean age at surgery was 12 years and 6 months (range 3 months to 21 years and 4 months). The types of spinal instrumentation utilized included occipital screws (94 cases); C1 lateral mass screws (115 cases); C2 pars/translaminar screws (143 cases); subaxial cervical lateral mass screws (95 cases); thoracic and lumbar spine traditional-trajectory and cortical-trajectory pedicle screws (234 cases); thoracic and lumbar sublaminar, subtransverse, and subcostal polyester bands (65 cases); S1 pedicle screws (103 cases); and S2 alar-iliac/iliac screws (56 cases). Complications related to spinal instrumentation included hardware-related skin breakdown (1.8%), infection (1.8%), proximal junctional kyphosis (1.0%), pseudarthroses (1.0%), screw malpositioning (0.5%), CSF leak (0.5%), hardware failure (0.5%), graft migration (0.3%), nerve root injury (0.3%), and vertebral artery injury (0.3%).CONCLUSIONSPediatric neurosurgeons with an interest in complex spine disorders in children should develop a comprehensive armamentarium of safe techniques for placing rigid and nonrigid spinal instrumentation even in the smallest of children, with low complication rates. The authors' review provides some benchmarks and outcomes for comparison, and furnishes a historical perspective of the past and future of pediatric spine surgery.

C1-2 Fixation Approach for Patients With Vascular Irregularities: A Case Report

In posterior spinal fusion (PSF), the vertebral artery is most vulnerable to injury at C1-2. C2 pedicle screws are often placed into the dorsomedial isthmus of C2. Alternative techniques include C2 laminar screws and wiring techniques. A 67-year-old male underwent PSF for persistent severe intractable neck pain and degeneration at C1-2. The patient had an enlarged left vertebral artery with midline migration into the C2 body. This pattern was within one standard deviation of normal; however, it rendered typical placement of a C2 pedicle screw unsafe. As a salvage, a C2 laminar screw was placed on the left to avoid risk of vertebral artery injury. The operation and recovery were without complication. C2 laminar screws can be viable alternatives to C2 pedicle screws in cases of midline vertebral artery migration or other vascular anomalies preventing normal safe placement of C2 pedicle screws.