Evaluating Lumbar Intervertebral Disc Degeneration on a Compositional Level Using Chemical Exchange Saturation Transfer: Preliminary Results in Patients with Adolescent Idiopathic Scoliosis.

Lumbar intervertebral disc (IVD) degeneration is characterized by structural and compositional changes. This study aimed to assess the glycosaminoglycan (GAG) content of IVDs of patients with adolescent idiopathic scoliosis (AIS) and healthy controls using GAG chemical exchange saturation transfer (gagCEST) imaging. Ten AIS patients (mean age 18.3 ± 8.2 years) and 16 healthy controls (mean age 25.5 ± 1.7 years) were included. Clinical standard morphologic MR images (T1w-, T2w-, and STIR-sequences), to rule out further spinal disorders and assess IVD degeneration using the Pfirrmann score, and compositional gagCEST sequences were acquired on a 3T MRI. In AIS patients, the most distal scoliotic curve was determined on whole-spine conventional radiographs and morphological MRI and IVDs were divided as to whether they were affected by scoliotic deformity, i.e., proximal (affected, aIVDs) or distal (unaffected, uaIVDs) to the stable vertebra of the most distal scoliotic curve. Linear mixed models were used to compare mean gagCEST-values. Over all segments, AIS-patients' IVDs exhibited significantly lower gagCEST-values than the controls: 2.76 [2.32, 3.20]% (AIS), 3.51 [3.16, 3.86]% (Control); p = 0.005. Meanwhile, no significant differences were found for gagCEST values comparing aIVDs with uaIVDs. In conclusion, as a powerful diagnostic adjunct, gagCEST imaging may be prospectively applied to detect early compositional degenerative changes in patients suffering from AIS.

Non-Specific Low Back Pain and Lumbar Radiculopathy: Comparison of Morphologic and Compositional MRI as Assessed by gagCEST Imaging at 3T.

Using glycosaminoglycan Chemical Exchange Saturation Transfer (gagCEST) magnetic resonance imaging (MRI), this study comparatively evaluated the GAG contents of lumbar intervertebral disks (IVDs) of patients with non-specific low back pain (nsLBP), radiculopathy, and asymptomatic volunteers to elucidate the association of clinical manifestation and compositional correlate. A total of 18 patients (mean age 57.5 ± 22.5 years) with radiculopathy, 16 age-matched patients with chronic nsLBP and 20 age-matched volunteers underwent standard morphologic and compositional gagCEST MRI on a 3T scanner. In all cohorts, GAG contents of lumbar IVDs were determined using gagCEST MRI. An assessment of morphologic IVD degeneration based on the Pfirrmann classification and T2-weighted sequences served as a reference. A linear mixed model adjusted for multiple confounders was used for statistical evaluation. IVDs of patients with nsLBP showed lower gagCEST values than those of volunteers (nsLBP: 1.3% [99% confidence intervals (CI): 1.0; 1.6] vs. volunteers: 1.9% [99% CI: 1.6; 2.2]). Yet, IVDs of patients with radiculopathy (1.8% [99% CI: 1.4; 2.1]) were not different from patients with nsLBP or volunteers. In patients with radiculopathy, IVDs directly adjacent to IVD extrusions demonstrated lower gagCEST values than distant IVDs (adjacent: 0.9% [99% CI: 0.3; 1.5], distant: 2.1% [99% CI: 1.7; 2.5]). Advanced GAG depletion in nsLBP and directly adjacent to IVD extrusions in radiculopathy indicates close interrelatedness of clinical pathology and compositional degeneration.

Adjacent segment degeneration and topping off. Never stop at the apex!

We investigated if applying the Transition system (Globus Medical Inc., Audubon, PA, USA) as topping off can prevent Adjacent Segment Degeneration (ASD) and if rate of ASD is increased if instrumentation stopped at the apex of the Lumbar Lordosis (LL). We enrolled 99 consecutive patients in a retrospective study who have been operated by instrumented fusion of the lumbar spine. Thirty patients were treated by topping of (Group 1), 69 patients received the standard procedure (Group 2). 18 patients of group 1 (60%) and 38 patients of group 2 (55%) developed ASD. The difference was not significant (P>0.05). In 17 patients (17%) instrumentation stopped at apex of LL. 14/17 patients (82%) developed an ASD. This influence was significant (P<0.05). Instrumented fusion of the lumbar spine should not stop at the apex of the lumbar curve. Topping off by hybrid dynamic fixation does not reduce the rate of ASD.

Navigation Versus Fluoroscopy in Multilevel MIS Pedicle Screw Insertion: Separate Analysis of Exposure to Radiation of the Surgeon and of the Patients.

STUDY DESIGN: This study was a retrospective radiographic analysis of consecutive patients. OBJECTIVES: To analyze exposure to radiation of the surgeon and-separately-of patients in minimally invasive surgery (MIS) of multilevel posterior stabilization by percutaneous pedicle screw insertion guided by navigation (PIN) versus percutaneous pedicle screw insertion guided by fluoroscopy (PIF). SUMMARY OF BACKGROUND DATA: Spine surgeons are exposed to a 12-fold higher dose of radiation than other nonspinal musculoskeletal surgeons and PIF in MIS leads to a 2-fold higher dose of radiation than in open surgery. PIN might reduce the dose of radiation for the surgeon and the patient, especially in multilevel MIS surgery. To the best of our knowledge, there are only rare data of short-segment fusions that do not focus on exposure to radiation of surgeons. METHODS: After power analysis, we included 205 consecutive screws (22 patients). We monitored dose of radiation (recorded separately for patient and surgeon), accuracy of screw placement, time of operation, and approach-related complications. RESULTS: In PIN, only 58.7% of dose area product (cGy×cm) per screw of PIF was determined for patients (P<0.01). The surgeon was only exposed to 19.9% of radiation per screw in PIN compared with dosage in PIF (P<0.01). Four of 205 screws (2.0%) were classified as being incorrectly positioned: 2 of 87 screws (2.3%) in PIF and 2 of 118 screws (1.7%) in PIN (P>0.05). We did not observe any wound infections. CONCLUSIONS: PIN in MIS is a safe procedure and does, compared with PIF, lead to significant reduction of radiation dose for patients and-even more-for spine surgeons.

Early versus late surgery of thoracic spine fractures in multiple injured patients: is early stabilization always recommendable?

BACKGROUND CONTEXT: Many institutions' retrospective studies investigated the effect of the timing of surgery on outcomes of polytraumatized patients with severe lesions of the thoracic spine and mainly found a better outcome for patients who were operated on less than 72 hours posttrauma. PURPOSE: We conducted a prospective study in a Level I trauma center to validate the retrospective data and to investigate other variables, in addition to the timing of surgery that may influence patient outcomes. STUDY DESIGN: Prospective observational clinical study. PATIENT SAMPLE: Within this prospective study at a Level I trauma center, we enrolled 38 multiple injured patients with unstable fractures of vertebral column from Level Th1 to L1. Further inclusion criteria consisted of an injury severity score of 16 or more and an intensive care unit (ICU) stay of more than 7 days. The age of included patients was limited from 16 or more to 75 or less years. OUTCOME MEASURES: Hospital stay, stay on ICU, and mortality. METHODS: Twenty-two patients were operated on less than or equal to 72 hours posttrauma, and 16 received late surgery greater than or equal to 72 hours posttrauma. RESULTS: Patients who received early surgery had a significantly higher mortality rate (p<.01) than those who received late surgery. Sixty-seven percent of our patients who had an initial hemoglobin (Hb) less than 10 mg/dL died. Seventy-five percent of those patients who had an Hb less than 10 mg/dL and received a thoracic drain died. CONCLUSIONS: Although some reports indicate advantages for early surgery for thoracic spine trauma in the polytraumatized patient, careful patient selection should be used. Based on the results of this prospective study, early surgery for thoracic spine trauma in patients with concomitant severe thoracic trauma and low initial Hb levels may pose a risk for poor clinical outcomes.

Treatment of Dens Fractures with Anterior Screw Fixation.

INTRODUCTION: Direct anterior screw fixation of the dens preserves C1-C2 rotation, and the reported fusion rates range from 88% to 100%. STEP 1 POSITIONING OF THE PATIENT: Exact positioning of the patient and use of image intensifiers are mandatory to obtain perfect anteroposterior and lateral views of the axis. STEP 2 SURGICAL APPROACH: The surgical approach is standardized, and the pretracheal layer can be exposed without violating any essential anatomic structures. STEP 3 ENTRY POINT OF THE SCREW: The perfect entry point is directly anterior-inferior at the base of C2; therefore, the anterior rim of the C2-C3 intervertebral disc must be penetrated. STEP 4 SCREW INSERTION: We use a single cannulated screw in most cases: insert the screw in the center of the dens with its tip perforating the cranial, cortical bone of the dens just posterior to the apex. STEP 5 WOUND CLOSURE: Precise and anatomic closure of the platysma determines the quality of the scar that will be visible after the operation. STEP 6 FOLLOW-UP: The patient wears a rigid collar for six weeks, removing it for body care; radiographic evaluations should be performed regularly. RESULTS: In a study of sixty-nine patients with a fracture of the dens, three of the thirteen patients who underwent direct anterior screw fixation had persistent instability and nonunion of the dens four months after surgery. Indications Contraindications Pitfalls & Challenges.

Treatment of Dens Fractures with Posterior Transarticular Fixation.

INTRODUCTION: Treatment of unstable dens fractures with posterior transarticular C1-C2 arthrodesis provides a biomechanically stable construct, even when poor bone quality is present, and a low rate of complications even in elderly patients; however, when this method of fixation is performed, cervical spine rotation is substantially reduced as compared with that associated with alternative fixation techniques. STEP 1 POSITIONING: Exact positioning of the patient and use of image intensifiers are mandatory to obtain appropriate anteroposterior and lateral views of C1 and C2. STEP 2 SURGICAL APPROACH: Use the modified technique of Magerl and Seemann, as it allows a less extensive approach to C1 and C2, and the drill can enter through two incisions at the level of T1. STEP 3 INSERTION OF SCREWS: Use smooth 2.0-mm Kirschner wires to prepare the canal for the screws, and subsequently replace them with 3.0-mm self-tapping screws. STEP 4 GALLIE FUSION: Perform a modified Gallie fusion, in addition to the transarticular screw fixation, to increase stability and osseous fusion between C1 and C2. STEP 5 WOUND CLOSURE: Perform meticulous closure of the wound to avoid wound-healing complications. RESULTS: In our original study, we treated twenty-five patients with posterior transarticular fixation.IndicationsContraindicationsPitfalls & Challenges.

Treatment algorithm for dens fractures: non-halo immobilization, anterior screw fixation, or posterior transarticular C1-C2 fixation.

BACKGROUND: The appropriate treatment of dens fractures is unclear. We established a staged treatment protocol for dens fractures and conducted a prospective study to evaluate the outcome of treatment based on this protocol. METHODS: We prospectively evaluated sixty-nine consecutive patients who presented to our institution with a dens fracture. The mean duration of follow-up was 9.7 months (range, six to fifty-eight months). Fractures were categorized as stable or unstable. Stable fractures were treated by immobilization in a rigid collar. Patients seventy-five years or older with unstable fractures, patients with a neurological deficit, and patients with Anderson and D'Alonzo type-III fractures underwent posterior transarticular C1-C2 stabilization. Unstable fractures in patients younger than seventy-five years were stabilized with direct anterior screw fixation. Thirty-one patients were treated with a Philadelphia collar, twenty-five with posterior transarticular fixation, and thirteen with direct anterior screw fixation. RESULTS: Fracture-healing or solid fusion of C1-C2 was documented in sixty-eight of sixty-nine treated patients at final follow-up. The remaining patient had a stable nonunion of the dens. Secondary procedures were performed in five patients. CONCLUSIONS: Our treatment algorithm based on dens fracture type, fracture stability, and patient age was associated with a high success rate. Evaluating fracture stability is crucial when considering nonoperative treatment. External stabilization with a rigid cervical collar was adequate for stable fractures of the dens and was associated with a high healing rate. Posterior transarticular screw fixation of C1-C2 was associated with a high success rate, including in elderly patients. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.