Pedicle screw fixation is a commonly utilized adjunct for lumbar interbody fusion, yet risks include screw malposition, pullout, loosening, neurovascular injury, and stress transfers leading to ...adjacent segment degeneration. This report describes the preclinical and initial clinical results of a minimally invasive, metal-free cortico-pedicular fixation device used for supplemental posterior fixation in lumbar interbody fusion.
Safety of arcuate tunnel creation was evaluated in cadaveric lumbar (L1–S1) specimens. A finite element analysis study evaluated clinical stability of the device to pedicular screw-rod fixation at L4–L5. Preliminary clinical results were assessed by analysis of Manufacturer and User Facility Device Experience database complications, and 6-month outcomes in 13 patients treated with the device.
Among 35 curved drill holes in 5 lumbar specimens, no breaches of the anterior cortex were identified. The mean minimum distance from the anterior surface of the hole to the spinal canal ranged from 5.1 mm at L1–L2 to 9.8 mm at L5–S1. In the finite element analysis study, the polyetheretherketone strap provided comparable clinical stability and reduced anterior stress shielding compared to the conventional screw-rod construct. The Manufacturer and User Facility Device Experience database identified 1 device fracture with no clinical sequelae among 227 procedures. Initial clinical experience showed a 53% decrease in pain severity (P = 0.009), a 50% decrease in Oswestry Disability Index (P < 0.001), and no device-related complications.
Cortico-pedicular fixation is a safe and reproducible procedure that may address limitations of pedicle screw fixation. Longer term clinical data in large clinical studies are recommended to confirm these promising early results.
Abstract
Background
Pedicle screw loosening and breakage are common causes of revision surgery after lumbar fusion. Thus, there remains a continued need for supplemental fixation options that offer ...immediate stability without the associated failure modes. This finite element analysis compared the biomechanical properties of a novel cortico-pedicular posterior fixation (CPPF) device with those of a conventional pedicle screw system (PSS).
Methods
The CPPF device is a polyetheretherketone strap providing circumferential cortical fixation for lumbar fusion procedures via an arcuate tunnel. Using a validated finite element model, we compared the stability and load transfer characteristics of CPPF to intact conditions under a 415 N follower load and PSS conditions under a 222 N preload. Depending on the instrumented levels, two different interbody devices were used: a lateral lumbar interbody device at L4–5 or an anterior lumbar interbody device at L5-S1. Primary outcomes included range of motion of the functional spinal units and anterior load transfer, defined as the total load through the disk and interbody device after functional motion and follower load application.
Results
Across all combinations of interbody devices and lumbar levels evaluated, CPPF consistently demonstrated significant reductions in flexion (ranging from 90 to 98%), extension (ranging from 88 to 94%), lateral bending (ranging from 75 to 80%), and torsion (ranging from 77 to 86%) compared to the intact spine. Stability provided by the CPPF device was comparable to PSS in all simulations (range of motion within 0.5 degrees for flexion–extension, 0.6 degrees for lateral bending, and 0.5 degrees for torsion). The total anterior load transfer was higher with CPPF versus PSS, with differences across all tested conditions ranging from 128 to 258 N during flexion, 89–323 N during extension, 135–377 N during lateral bending, 95–258 N during torsion, and 82–250 N during standing.
Conclusion
Under the modeled conditions, cortico-pedicular fixation for supplementing anterior or lateral interbody devices between L4 and S1 resulted in comparable stability based on range of motion measures and less anterior column stress shielding based on total anterior load transfer measures compared to PSS. Clinical studies are needed to confirm these finite element analysis findings.
Three noncontiguous spinal implant sites in 1 rabbit were challenged with Staphylococcus aureus and local antibiotic prophylaxis was given with gentamicin in controlled-release microspheres ...(poly(lactic-coglycolic-acid) PLGA). Postoperative biomaterial-centered infection on and around the titanium rods was assessed using standard bacterial quantification essays.
To assess surgical site and biomaterial-centered infection reduction with controlled release gentamicin from microspheres against S. aureus.
A postoperative biomaterial-centered infection can be devastating after successful thoracolumbar spinal surgery and puts a high burden on patients, families, surgeons, and hospitals, endangering both our healthcare budget and our ability to perform challenging cases in patients with increasing numbers of comorbidities. Systemic antibiotics often do not reach "dead-space" hematomas where bacteria harbor after surgery, whereas local, controlled release gentamicin prophylaxis through PLGA microspheres showed favorable pharmacokinetics data to achieve local bactericidal concentrations for up to 7 days after surgery.
A well published rabbit spinal implant model with systemic cephalosporin prophylaxis was challenged to create a baseline infection of approximately 70% in control sites. We then challenged 3 noncontiguous titanium rods inside the laminectomy defect with 10e6 colony forming units S. aureus and randomly treated 2 sites with gentamicin PLGA microspheres and 1 site with PLGA carrier only (control). Standard quantification techniques were used to assess biomaterial centered and soft tissue bacterial growth after 7 days.
After establishing reliable infection rates in control sites, the therapeutic arm of the study was started. Surgical site infections were found in 75% of control sites, whereas gentamicin microspheres reduced the incidence down to 38% in the same rabbits. Biomaterial-centered infection was reduced from 58% to 23% only in all sites challenged with 10e6 S. aureus.
Postoperative, biomaterial-centered infection was reduced at least 50% with intraoperative gentamicin microspheres in the face of systemic cephalosporin prophylaxis and high dose S. aureus in a laminectomy defect in rabbits. The data are statistically and clinically significant, and further animal testing is planned to confirm these results.
The increasing adoption of minimally invasive techniques for spine surgery in recent years has led to significant advancements in instrumentation for lumbar interbody fusion. Percutaneous pedicle ...screw fixation is now a mature technology, but the role of expandable cages is still evolving. The capability to deliver a multiexpandable interbody cage with a large footprint through a narrow surgical cannula represents a significant advancement in spinal surgery technology. The purpose of this report is to describe a multiexpandable lumbar interbody fusion cage, including implant characteristics, intended use, surgical technique, preclinical testing, and early clinical experience. Results to date suggest that the multiexpandable cage allows a less invasive approach to posterior/transforaminal lumbar interbody fusion surgery by minimizing iatrogenic risks associated with static or vertically expanding interbody prostheses while providing immediate vertebral height restoration, restoration of anatomic alignment, and excellent early-term clinical results.
Central Cord Syndrome Nowak, Douglas D; Lee, Joseph K; Gelb, Daniel E ...
Journal of the American Academy of Orthopaedic Surgeons,
12/2009, Letnik:
17, Številka:
12
Journal Article
Recenzirano
Central cord syndrome is the most common type of incomplete spinal cord injury. This syndrome most often occurs in older persons with underlying cervical spondylosis caused by a hyperextension ...mechanism. It also occurs in younger persons who sustain trauma to the cervical spine and, less commonly, as a result of nontraumatic causes. The upper extremities are more affected than the lower extremities, with motor function more severely impaired than sensory function. Central cord syndrome presents a spectrum, from weakness limited to the hands and forearms with sensory preservation, to compete quadriparesis with sacral sparing as the only evidence of incomplete spinal cord injury. Historically, treatment has been nonsurgical, but recovery is often incomplete. Early surgical treatment of central cord syndrome remains controversial. However, recent studies have shown benefits, particularly of early surgery to decompress the spinal cord in patients with pathologic conditions revealed by radiography or MRI.
Minimally invasive posterior fixation Wang, Michael Y; Anderson, D Greg; Poelstra, Kornelis A ...
Neurosurgery
63, Številka:
3 Suppl
Journal Article
Recenzirano
Significant advances have been made in the contemporary management of thoracolumbar spinal deformities, including improved segmental bony fixation, techniques for osteotomy, and mechanically powerful ...reduction maneuvers, which now allow the spinal surgeon to correct severe, complex, and rigid spinal deformities. However, one of the major limitations of surgical intervention has been the high complication rates associated with these surgical endeavors. Much of the morbidity associated with posterior deformity surgery relates to the extensive soft tissue destruction necessary to gain access to multiple segments of the axial skeleton. The open exposures for long-segment fixation result in additional blood loss, increased rates of infection, and prolonged immobilization caused by postoperative pain. Minimally invasive techniques attempt to overcome these drawbacks of the open exposures, and this report reviews preliminary experience in treating spinal deformities with long-segment minimally invasive internal fixation.
We describe a new arthroscopic technique for repair of meniscal ossicles in support of the theory that meniscal ossicles are traumatic in nature. Using a standard inferolateral portal, the ...arthroscope is passed under the posterior cruciate ligament to permit visualization of the “root” of the medial meniscus with a matching donor lesion on the tibia. A limited debridement should be performed of the donor site as well as the posterior horn of the meniscus if it has healed over with fibrocartilage to allow bone-to-bone healing. A posteromedial working portal is made at an angle amenable to the repair and a 6-mm cannula is placed. A Beath passing pin commonly used for anterior cruciate ligament reconstruction is used to pass suture for the outside-inside-out repair. The pin is passed through the cannula in the posterior medial portal. The root of the medial meniscus and the avulsed ossicle are pierced with the Beath pin and tensioned, after which the pin is drilled into the matching donor site and out through the tibia. Two passes are used to create a mattress suture through the ossicle, and the suture is tied over a bone bridge on the anterolateral tibia.
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