Results of posterior spinal fusion after failed anterior vertebral body tethering.

PURPOSE: In patients with adolescent idiopathic scoliosis (AIS) undergoing anterior vertebral tethering (AVBT), some will subsequently require posterior spinal fusion (PSF). Limited data exist on clinical and radiographic outcomes of fusion after tether failure. METHODS: 490 patients who underwent AVBT were retrospectively analyzed. Twenty patients (4.1%) subsequently underwent conversion to PSF. A control group of patients with primary PSF (no previous AVBT) was matched for comparison. Data were compared using paired t-tests and Fisher Exact Tests. RESULTS: There was a significant increase in estimated blood loss (EBL) (p = 0.002), percent estimated blood volume (%EBV) (p = 0.013), operative time (p = 0.002), and increased amount of fluoroscopy (mGy) (p = 0.04) as well as number of levels fused (p = 0.02) in the AVBT conversion group compared to primary fusion. However, no difference was found in implant density (p = 0.37), blood transfusions (p = 0.11), or intraoperative neuromonitoring events (p > 0.99). Both groups attained similar thoracic and lumbar percent correction (major coronal curve angle) from pre-op to the latest follow-up (thoracic p = 0.507, lumbar p = 0.952). CONCLUSION: A subset of patients with AVBT will require conversion to PSF. Although technically more challenging, revision surgery can be safely performed with similar clinical and radiographic outcomes to primary PSF.

Pain After Anterior Vertebral Body Tethering: Incidence, Risk Factors, and Timing.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To examine the incidence and risk factors for postoperative pain following anterior vertebral body tethering (AVBT) for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Up to 78% of patients with AIS report preoperative pain; it is the greatest patient concern surrounding surgery. Pain significantly decreases following posterior spinal fusion, but pain following AVBT is poorly understood. MATERIALS AND METHODS: We retrospectively reviewed 279 patients with a two-year follow-up after AVBT for AIS. We collected demographic, radiographic, and clinical data pertinent to postoperative pain at each time interval of preoperative and postoperative visits (6 wk, 6 mo, 1 y, and annually thereafter). RESULTS: Within our cohort, 68.1% of patients reported preoperative pain. Older age ( P =0.014) and greater proximal thoracic ( P =0.013) and main thoracic ( P =0.002) coronal curve magnitudes were associated with preoperative pain. Pain at any time point > 6 weeks postoperatively was reported in 41.6% of patients; it was associated with the female sex ( P =0.032), need for revision surgery ( P =0.019), and greater lateral displacement of the apical lumbar vertebrae ( P =0.028). The association between preoperative and postoperative pain trended toward significance ( P =0.07). At 6 months postoperatively, 91.8% had pain resolution; the same number remained pain-free at the time of last follow-up. The presence of a postoperative complication was associated with new-onset postoperative pain that resolved ( P =0.009). Only 8.2% had persistent pain, although no risk factors were found to be associated with persistent pain. CONCLUSION: In our cohort of 279 patients with a minimum 2-year follow-up after AVBT, 68.1% reported preoperative pain. Nearly 42% reported postoperative pain at any time point, but only 8.2% had persistent pain. Postoperative pain after AVBT was associated with female sex, revision surgery, and Lenke lumbar modifier. AVBT is associated with a significant reduction in pain, and few patients report long-term postoperative pain.

What Happens After a Vertebral Body Tether Break? Incidence, Location, and Progression With Five-year Follow-up.

STUDY DESIGN: Retrospective review. OBJECTIVE: To study risk factors for anterior vertebral body tether (VBT) breakage. SUMMARY OF BACKGROUND DATA: VBT is used to treat adolescent idiopathic scoliosis in skeletally immature patients. However, tethers break in up to 48% of cases. MATERIALS AND METHODS: We reviewed 63 patients who underwent thoracic and/or lumbar VBT with a minimum five-year follow-up. We radiographically characterized suspected tether breaks as a change in interscrew angle >5°. Demographic, radiographic, and clinical risk factors for presumed VBT breaks were evaluated. RESULTS: In confirmed VBT breaks, the average interscrew angle change was 8.1°, and segmental coronal curve change was 13.6°, with a high correlation ( r =0.82). Our presumed VBT break cohort constituted 50 thoracic tethers, four lumbar tethers, and nine combined thoracic/lumbar tethers; the average age was 12.1±1.2 years and the mean follow-up was 73.1±11.7 months. Of 59 patients with thoracic VBTs, 12 patients (20.3%) had a total of 18 breaks. Eleven thoracic breaks (61.1%) occurred between two and five years postoperatively, and 15 (83.3%) occurred below the curve apex ( P <0.05). The timing of thoracic VBT breakage moderately correlated with more distal breaks ( r =0.35). Of 13 patients who underwent lumbar VBT, eight patients (61.5%) had a total of 12 presumed breaks. Six lumbar breaks (50%) occurred between one and two years postoperatively, and seven (58.3%) occurred at or distal to the apex. Age, sex, body mass index, Risser score, and curve flexibility were not associated with VBT breaks, but the association between percent curve correction and thoracic VBT breakage trended toward significance ( P =0.054). Lumbar VBTs were more likely to break than thoracic VBTs ( P =0.016). Seven of the patients with presumed VBT breaks (35%) underwent revision surgery. CONCLUSIONS: Lumbar VBTs broke with greater frequency than thoracic VBTs, and VBT breaks typically occurred at levels distal to the curve apex. Only 15% of all patients required revision. LEVEL OF EVIDENCE: 3.

Complete paraplegia 36 h after attempted posterior spinal fusion for severe adolescent idiopathic scoliosis: a case report.

INTRODUCTION: The incidence of neurologic complications with spinal surgery for adolescent idiopathic scoliosis (AIS) has been reported to be 0.69%. This rare complication typically occurs during surgery or immediately postoperatively. We report the occurrence of a delayed neurologic deficit that presented 36 h after the initial surgery of a staged posterior spinal fusion for severe AIS. CASE PRESENTATION: A 12-year-old girl with severe thoracolumbar AIS of 125° underwent attempted posterior spinal fusion from T2-L4. The case was complicated by a transient loss of transcutaneous motor evoked potentials (TcMEP) that resolved with an increase in the mean arterial pressure (MAP) and relaxation of curve correction with rod removal. The patient awoke with normal neurologic function. She had a transient decrease in MAP 36 h post-op and awoke on postoperative day #2 with nearly complete lower extremity paraplegia (American Spinal Injury Association [ASIA] Impairment Scale B). Emergent exploration and removal of the concave apical pedicles resulted in improvement of TcMEPs and return of function. DISCUSSION: Delayed postoperative neurologic deficit is a very rare phenomenon, with only a few case reports in the literature to date. The delayed neurologic decline of our patient was likely secondary to a transient episode of postoperative hypotension combined with spinal cord compression by the apical concave pedicles. Close monitoring and support of spinal cord perfusion as well as emergent decompression are imperative in the setting of a delayed neurologic deficit. Further multicenter study on this rare occurrence is underway to identify potential causes and improve treatment.

Evolución clínica de pacientes sometidos a bloqueo facetario y radiculares selectivos atendidos en el servicio de neurocirugía del ISSS entre junio-diciembre 2015 / Clinical evolution of patients undergoing selective facet and root block treated at the neurosurgery service of the ISSS between June-December 2015

En el servicio de neurocirugía el principal motivo de consulta está relacionada con la columna vertebral, siendo el dolor la queja más común en todos los casos. Lo que se mostrara en este trabajo es la evolución clínica de estos pacientes, atendidos en el servicio de neurocirugía del ISSS por cuadro de dolor lumbar o lumbociatico debido a hernia lumbar, canal estrecho lumbar de múltiples etiologías, que ameritan tratamiento quirúrgico, en el periodo de tiempo comprendido entre junio a diciembre del 2015, esta medida se evalúa para poderla implementar en todos los pacientes que necesiten procedimiento quirúrgico y por motivos meramente administrativos, como: el número de pacientes quirúrgicos que tenga su cirujano a cargo o por la espera de cupo quirúrgico en sala de operaciones electivas, el tiempo de espera para el procedimiento quirúrgico es largo; gracias al bloqueo facetario y radiculares selectivos se alivia de esta manera los síntomas de forma momentánea, más sin embargo no se pretende hacer creer a los pacientes que esta será una medida terapéutica definitiva solamente será una medida para palear los síntomas en pacientes con patología lumbar demostrada (canal lumbar estrecho multifactorial, hernia lumbar). Realizamos un estudio longitudinal retrospectivo a partir de los pacientes evaluados en el servicio de neurocirugía, pacientes con cuadro que ameritase cirugía ya sea por hernia discal, hipertrofia facetaria o ambas y cuyo ingreso hubiese sido por dolor. En total se evaluó la evolución clínica de 66 pacientes, 43 hombres y 23 mujeres, de los cuales 25 tenian hernias discales lumbares, 26 hipertrofias facetarias y 15 ambos padecimientos. Se les realizo a los 66 pacientes una evaluación previa al procedimiento para deternimar la escala visual análoga inicial. Se realizó procedimiento de bloqueo facetario y nervioso selectivo utilizando bupivacaina y triamcinolona en los 66 pacientes, en todos se realizaron ambos bloqueos. Posteriormente se realizó nueva evaluación en el tercer mes post intervención y se reevaluó escala visual análoga del dolor. Todos los datos fueron recogidos de expediente clínico, se realizó tabla matriz en Excel 2016 para MAC y se utilizó método estadístico de T de student para muestras emparejadas. Se tuvo a bien dividir el grupo en tres: hernias, hipertrofia facetaria y ambos padecimientos, en los tres la diferencia de EVA pre y post tuvo significancia estadística, por lo que se logró concluir que el procedimiento de bloqueo radicular selectivo y facetario disminuye el cuadro de dolor en más del 50%