Minimally invasive facet restoration implant for chronic lumbar zygapophysial pain: 1-year outcomes.

BACKGROUND: The zygapophysial (facet) joint is the primary pain generator in one third of chronic low back pain cases. Current treatment options include temporarily palliative nonsurgical approaches, facet injections, radiofrequency denervation, and, rarely, lumbar arthrodesis. The purpose of this study was to assess the safety and effectiveness of a minimally invasive implant intended to restore facet joint function in patients with chronic lumbar facetogenic pain. METHODS: This prospective, multi-center feasibility study enrolled patients with confirmed lumbar facetogenic joint pain at 1 or 2 levels who underwent at least 6 months of unsuccessful nonoperative care. Patients received a minimally invasive implant (Glyder® Facet Restoration Device, Zyga Technology, Inc., Minnetonka, MN) intended to restore facet joint function while preserving the native anatomy. Main outcomes included back pain severity using a visual analogue scale, back-specific disability using the Oswestry Disability Index (ODI), and adverse events adjudicated by an independent Clinical Events Committee. RESULTS: Of 40 enrolled patients, 37 patients received the facet restoration implant and 34 patients had complete 1-year follow-up data available. Over the 1-year follow-up period, back pain severity decreased 41% and ODI decreased 34%, on average. Freedom from a device- or procedure-related serious adverse event through 1 year was 84%. Implant migration was observed in 3 patients and implant expulsion from the facet joint occurred in 3 patients. In total, 2 (5.4%) patients underwent implant removal through 1 year post-treatment. CONCLUSIONS: A minimally invasive facet restoration implant is a promising treatment option in select patients with chronic lumbar zygapophysial pain who have exhausted nonsurgical treatments, with therapeutic benefit persisting at 1 year follow-up.

How to prevent small stature in Rett syndrome-associated collapsing spine syndrome.

Severe scoliosis in Rett syndrome is an important orthopedic, neurologic, and pediatric problem. The curve in Rett syndrome is of a neurologic type, has its highest incidence during early childhood, and shows rapid progression. In this study, the authors report the results of a 4-year follow-up of a 10-year-old Rett syndrome female patient with early onset and severe rapid progressive thoracolumbar scoliosis. The first signs of spinal deformity were documented at age 3 years. During adolescence, the patient developed a 115-degree thoracolumbal scoliosis with reduced respiratory volume due to a collapsing spine syndrome. To stop this life-threatening progression of the curve, the patient was treated by a 2-stage surgical procedure. The combination of an anterior release, halo traction, and posterior instrumented fusion from Th3 to L5 using a computer-assisted technique was performed. An excellent reduction of the deformity was achieved (postoperative 24-degree Cobb angle). After 4 years, the authors found a radiologically solid spinal fusion and no progression of the deformity. Operative treatment regimes and etiology of severe spinal deformities in Rett syndrome were discussed. The high perioperative risks in Rett syndrome patients who underwent spinal surgery may be reduced by an early cooperation between orthopedic and pediatric specialists. When considering recent data from literature, it can be concluded that an early correction of spine deformities in Rett syndrome patients may prevent a life-threatening collapsing spine syndrome.

Remodeling of the spine in spondylodiscitis of children at the age of 3 years or younger.

Spondylitis/spondylodiscitis is still an uncommon diagnosis often with a delay in diagnosis and treatment due to the uncharacteristic symptoms. The aim of this study is to increase the awareness and outline a pattern of investigation and treatment. We present six children with an average age of 23 months (19-33 months) at time of diagnosis, conservative treated and with a mean follow-up of 31 months (12-65 months). The evaluation included past medical history, clinical symptoms, X-rays, MRI-investigations and laboratory studies [CRP, erythrocytes sedimentation rate (ESR), white blood count (WBC) and blood cultures] during the course of treatment and follow-up. The predominate clinical findings were: limp, refusal to walk and/or back pain. The mean duration of symptoms until presentation at our clinic was 24 days (4-42 days), the final diagnosis was set after an average of 12 days (7-14 days). Laboratory findings were unspecific but ESR best correlated with the clinical symptoms during the therapy. Five patients were treated by parenteral antibiotics for a minimum of 3 weeks, followed by oral antibiotics adapted to the clinical and laboratory findings. One child received a combined antituberculous chemotherapy after positive skin test for tbc. All six children were immobilized with a body-plaster-cast for an average time of 15 weeks (5-26 weeks). Four patients additionally were treated by further corset therapy for an average of 10 months (3-18 months). Radiological findings on plane X-rays (a.p. and lateral views) at time of diagnosis were decreased height of the disk space and erosions of adjacent vertebral endplates and residues of these radiological changes with signs of bony healing (sclerotic vertebral endplates or partial fusion) were seen at the latest follow-up. There was no case of instability or deformity like scoliosis or kyphosis. The MRI showed the earliest detectable typical vertebral bone involvements and confirmed the diagnosis in combination with laboratory findings and clinical symptoms. Spondylitis/spondylodiscitis should be considered as diagnosis in children with refusal to walk or gait disturbances especially in combination with elevated ESR. MRI is the tool of choice to set the diagnosis early. With an adequate and early therapy of bracing (body-plaster-cast), antibiotics and clinical monitoring good long-term result without spine instability or deformity can be achieved.

Pullout strength of anterior spinal instrumentation: a product comparison of seven screws in calf vertebral bodies.

A lot of new implant devices for spine surgery are coming onto the market, in which vertebral screws play a fundamental role. The new screws developed for surgery of spine deformities have to be compared to established systems. A biomechanical in vitro study was designed to assess the bone-screw interface fixation strength of seven different screws used for correction of scoliosis in spine surgery. The objectives of the current study were twofold: (1) to evaluate the initial strength at the bone-screw interface of newly developed vertebral screws (Universal Spine System II) compared to established systems (product comparison) and (2) to evaluate the influence of screw design, screw diameter, screw length and bone mineral density on pullout strength. Fifty-six calf vertebral bodies were instrumented with seven different screws (USS II anterior 8.0 mm, USS II posterior 6.2 mm, KASS 6.25 mm, USS II anterior 6.2 mm, USS II posterior 5.2 mm, USS 6.0 mm, USS 5.0 mm). Bone mineral density (BMD) was determined by quantitative computed tomography (QCT). Failure in axial pullout was tested using a displacement-controlled universal test machine. USS II anterior 8.0 mm showed higher pullout strength than all other screws. The difference constituted a tendency (P = 0.108) when compared to USS II posterior 6.2 mm (+19%) and was significant in comparison to the other screws (+30 to +55%, P < 0.002). USS II posterior 6.2 mm showed significantly higher pullout strength than USS 5.0 mm (+30%, P = 0.014). The other screws did not differ significantly in pullout strength. Pullout strength correlated significantly with BMD (P = 0.0015) and vertebral body width/screw length (P < 0.001). The newly developed screws for spine surgery (USS II) show higher pullout strength when compared to established systems. Screw design had no significant influence on pullout force in vertebral body screws, but outer diameter of the screw, screw length and BMD are good predictors of pullout resistance.

Radiological evaluation of unstable (acute) slipped capital femoral epiphysis treated by pinning with Kirschner wires.

Treatment of slipped capital femoral epiphysis is still controversial with regard to the implants used for stabilization and the need for prophylactic treatment of the contralateral, unaffected, side. The objective of this study was to ascertain whether prophylactic transfixation of the epiphysis with Kirschner wires in patients with unstable slipped capital femoral epiphysis resulted in significant disturbance of the growth plate and impairment of further growth of the femoral neck and head. Between 1990 and 1999, 29 patients with unstable slipped capital femoral epiphysis were simultaneously treated with internal fixation of the epiphysis and metaphysis with 3-4 Kirschner wires on the affected and the not (yet) affected side. After a mean follow-up of 3.5 years, we evaluated the hip joints radiologically, analysing different roentgenological parameters (CCD angle, femoral head diameter, length of the femoral neck and sphericity of the femoral head). CCD angle, femoral head diameter and length of the femoral neck showed statistically significant (P<0.001, Student's t-test) differences between the affected and unaffected, but prophylactically pinned, sides. Asphericity of the femoral head was found in six cases only on the affected side, whereas all hips, which were operated prophylactically, showed spherical femoral heads at follow-up (P<0.02, Pearson's chi test). These results indicate that the slip itself may cause impairment of the femoral growth plate in patients with unstable slipped capital femoral epiphysis and not stabilization with Kirschner wires. Compared with other series from the literature using different implants (screws, nails), prophylactic transfixation of the epiphysis and metaphysis with Kirschner wires is less compromising to the growth plate on the not (yet) affected side.

Ultrasound-guided botulinum toxin injection technique for the iliopsoas muscle.

Intramuscular botulinum toxin A injections are beneficial for the treatment of functional shortening of the iliopsoas muscle, but it is difficult to achieve precise needle positioning and injection. As a solution to this we present an ultrasound-guided injection technique for the iliopsoas muscle using an anterior approach from the groin. The procedure was performed 26 times in 13 patients (seven males, six females; mean age 11 years, SD 9 years 8 months; age range 4 to 31 years), 10 times bilaterally. Indications were functional iliopsoas shortening due to cerebral palsy (17 hips), hereditary spastic paraplegia (four hips), and Perthes disease (five hips). In all cases the iliopsoas muscle was identified easily by ultrasound; the placement of the injection needle and injection into the site of interest were observed during real time. No complications were encountered. Botulinum toxin A (BTX-A) injections have become established as a standard procedure for the treatment of functional shortening of different muscles in persons with spasticity or dystonia (Kessler et al. 1999, Bakheit et al. 2001, Kirschner et al. 2001). Optimal needle placement is essential to avoid severe side effects and to assess lack of response to the drug or incorrect region of injection. While injection into superficial, very palpable muscles is quite easy, the approach to other muscles such as the iliopsoas muscle may be more difficult and the placement of the needle for an optimal injection site is harder to control. As a solution to this, we present an ultrasound-guided injection technique. The main indications for BTX-A injections in the iliopsoas muscle are dynamic hip flexion deformities mostly due to spastic conditions which may compromise walking (increased anterior pelvic tilt during the whole gait cycle, decreased hip extension at terminal stance, increased peak hip flexion during swing; Molenaers et al. 1999. Another indication might be decentration of the femoral head (as part of an injection programme which also includes other muscles like the adductors and the medial hamstrings) for pain relief, reducing care difficulties and, possibly, prevention of further decentration (Porta 2000, Foster et al. 2001, Deleplanque et al. 2002, Lubik et al. 2002). In Perthes disease, BTX-A injections in the iliopsoas muscle and the adductors may prevent a fixed deformity, which is a negative prognostic factor.

Clinical outcome in monosegmental fusion of degenerative lumbar instabilities:instrumented versus non-instrumented.

BACKGROUND: Degenerative lumbar instabilities are one of the major reasons for low back pain, especially in elderly people. There is still controversy in the literature about the clinical outcome of instrumented monosegmental fusions compared to noninstrumented posterolateral fusions. MATERIAL/METHODS: In this study we described the postoperative outcome of 33 patients who underwent posterolateral monosegmental spinal fusion:instrumented (17 patients)or noninstrumented (16 patients).All patients received the same instrumentation system. Medical history (considering daily activities,sports,social contacts and quality of life),clinical examination and radiological analysis served as evaluation parameters. Data were collected by a questionnaire based on the Oswestry Disability Score for low back pain. RESULTS: 86.6%of all subjects showed an improvement of postoperative health status. Although patients with fusion without internal fixation needed a reduced dose of postoperative analgesics compared to the monosegmental non-instrumented group,there were no statistical differences in patient-reported,clinical and radiographical outcome between the two groups. CONCLUSIONS: The results do not indicate a benefit in outcome from added instrumentation in elective lumbar fusions. This should be considered in each single case when a spinal fusion in the treatment of degenerative lumbar instability is indicated.