Transiliac Endoscopic-Assisted L5S1 Intraforaminal Lumbar Interbody Fusion: Technical Considerations and Potential Complications.

OBJECTIVE: We sought to determine the clinical outcomes, complications, and fusion rates in transiliac endoscopic-assisted L5S1 intraforaminal lumbar interbody fusion (iLIF). METHODS: Between September 2020 and September 2021, patients with L5S1 degenerative disk disease were enrolled in a prospective study on transiliac L5S1 iLIF and followed for a minimum of 12 months. Conflict of the preoperative planned approach with the ilium was mandatory. The primary outcome measures were the Oswestry Disability Index, the visual analog scale (VAS) score for low back pain (VAS back) and leg pain (VAS leg), and the modified MacNab criteria. The secondary outcomes were complications and fusion rates. RESULTS: Five consecutive patients were enrolled: 2 males and 3 females with a mean age of 50 ± 12.9. All had 12 months' follow-up. The mean improvement in the Oswestry Disability Index, VAS back, and VAS leg (44 ± 11.75, 6.6 ± 1.7, and 4.7 ± 4.2, respectively) was more than 3 times the minimum clinically important difference. The modified MacNab criteria were good or excellent in 80% of cases at all endpoints. Three patients had ipsilateral lower limb dysesthesia. One patient had revision surgery for foraminal bone fragment removal. All patients achieved fusion. CONCLUSIONS: The transiliac iLIF is a feasible but demanding surgical technique that allows overcoming cases in which the ilium prevents endoscopic transforaminal access to L5S1. Our preliminary results had good clinical outcomes and high fusion rates. The main complication was late-onset dysesthesia of the ipsilateral lower limb, 10 to 14 days after surgery. Special care must be taken to prevent L5 dorsal root ganglion injury.

Transforaminal Endoscopic Approach to L5S1: Imaging Characterization of the Lower Lumbar Spine and Pelvis for Surgical Planning.

OBJECTIVE: To determine and compare pelvic and lumbosacral reference parameters with computed tomography in patients with low back pain (LBP) and a control group of asymptomatic patients to provide quantification data and morphological correlations for L5S1 transforaminal endoscopic approach (L5S1TEA). METHODS: We prospectively evaluated 100 patients with LBP and a control group of 100 individuals, with spinopelvic computed tomography. We measured lumbopelvic and L5S1 transforaminal approach parameters: maximum approach angle (maxAA) and minimum approach angle (minAA) and skin incision (maxSI and minSI), iliac crest (IC) projection at intersection point (ICPi), distance between the projected intersection of maxAA with the ilium (ICi) and the posterior limit of the IC (ΔICi-ICpost), and distance between ICi and spinous process (ΔICi-SP). RESULTS: Females and ICPi were increased in the LBP group: maxAA: 48.38° ± 5.09°; minAA:32.5° ± 3.90°; maxSI: 11.39 ± 1.86 cm; and minSI: 8.30 ± 1.48 cm. Ilium intersection was increased in males; IC projection at the highest point (ICPh) was higher than ICPi; maxAA intersected the ilium in 28% and minAA in 1.5% of cases; ICi was positively correlated with facet angle, ICPh, and ICPi and negatively with ΔICi-SP. CONCLUSIONS: Our results set preliminary reference values for L5S1TEA surgical planning. Besides higher ICPi, there were no differences between groups in measured parameters. Traditional IC height (ICPh) does not correspond to the point of intersection of the approach and is significantly higher than ICPi. ICi correlated to higher facet angle values, ICPh and ICPi grades, and lower ΔICi-SP. Potential conflict with the ilium is increased in the male population. IC is not impeditive of L5S1TEA in most cases.

Transiliac endoscopic assisted ilif: a cadaveric study / Ilif assistida por endoscopia por via transilíaca: estudo em cadáver / Ilif asistida por endoscopia transilíaca: estudio en cadáver

ABSTRACT Objective: Demonstrate the feasibility of endoscopic assisted L5S1 intraforaminal lumbar interbody fusion (iLIF) through a transiliac approach. Methods: Ten transiliac iLIF and ten supra iliac iLIF were performed bilaterally at L5S1 in five randomly selected fresh-frozen human cadavers. The following measurements were recorded: distances from the transiliac track to the iliac crest, posterior superior iliac spine, and superior gluteal neurovascular bundle; pelvic parameters; approach angles; cage's lateral and AP center point ratio (CPR); percentage of the cage crossing the midline in the AP and lateral views. Endplate integrity was assessed through endoscopic visualization. In addition, the facet joint, sacroiliac joint, iliolumbar ligament, and exiting and traversing nerve roots were checked for integrity through anatomic dissection. Results: In the transiliac technique, the axial and coronal approach angles were significantly decreased by 13.5º (95% CI -15.5; -11.5; p value<0.001) and 13.2º (95% CI -15.3; -11.1; p value<0.001), respectively, the sagittal approach angle was significantly increased by 5.4º (95% CI 1.8,8.9; p-value = 0.008), and the AP CPR was significantly higher (MD 0.16; 95% CI 0.12,0.20; p value<0.001). The percentage of the cage crossing the AP view's midline was increased by 31.6% (95% CI 19.8,43.4; p value<0.001). The integrity of endplates, facet joints, sacroiliac joints, iliolumbar ligament, and exiting and traversing nerve roots was maintained. Conclusion: L5S1 transiliac iLIF is a feasible surgical technique. It allows a more centrally placed interbody cage in the coronal plane without compromising the anterior position in the lateral plane. The integrity of the major anatomic structures at risk was preserved. Evidence Level III: A case-control study.

Resumo: Objetivo: Demonstrar a viabilidade da fusão intersomática lombar assistida por endoscopia (iLIF) em L5S1 através de abordagem transilíaca. Métodos: Dez iLIF por via transilíaca e dez iLIF por via suprailíaca foram realizados bilateralmente em L5S1 em cinco cadáveres selecionados aleatoriamente. Foram registadas as seguintes medidas: Distâncias da via transilíaca até a crista ilíaca, crista ilíaca póstero-superior e feixe neurovascular do glúteo superior; parâmetros pélvicos; ângulos da abordagem; relação do ponto central lateral e AP do cage (CPR); percentagem do cage cruzando a linha média nas incidências AP e perfil. A integridade das placas vertebrais foi avaliada através de visualização endoscópica. Foi verificada através de dissecção anatómica a integridade das articulações facetárias, sacroilíacas, ligamento iliolombar e raízes de L5 e S1. Resultados: Na técnica transilíaca, os ângulos de abordagem axial e coronal foram significativamente menores em 13,5º (CI 95% -15,5;-11,5; p<0,001) e 13,2º (CI 95% -15,3;-11,1; p<0,001 ), respectivamente, o ângulo de abordagem sagital aumentou significativamente em 5,4º (CI 95% 1,8,8,9; p = 0,008), e o AP CPR foi significativamente maior (MD 0,16; CI 95% 0,12,0,20; p <0,001). A percentagem do cage cruzando a linha média em AP foi superior em 31,6% (CI 95% 19,8,43,4; valor p<0,001). A integridade das placas vertebrais, articulações facetadas, articulações sacroilíacas, ligamento iliolombar e raízes de L5 e S1 foi mantida. Conclusão: A realização de iLIF L5S1 por via transilíaca é uma técnica cirúrgica viável. Permite que o cage seja colocado mais centrado no plano coronal sem comprometer a posição anterior no plano sagital. A integridade das principais estruturas anatómicas em risco foi preservada. Nível de Evidencia III: Estudo caso-controle.

Resumen: Objetivo: Demostrar la viabilidad de la fusión intersomática lumbar asistida por endoscopia (iLIF) en L5S1 con un abordaje transilíaco. Métodos: Se registraron las siguientes mediciones: distancias del abordaje transilíaco a la cresta ilíaca, la cresta ilíaca posterosuperior y el haz neurovascular glúteo superior; parámetros pélvicos; ángulos de abordaje; relación del punto medio lateral y AP del cage (CPR); porcentaje del cage que cruza la línea media en las incidencias AP y perfil. Se evaluó la integridad de las placas vertebrales por visualización endoscópica. Se comprobó la integridad de las articulaciones facetarias, las articulaciones sacroilíacas, el ligamento iliolumbar y las raíces de L5 y S1 mediante disección anatómica. Resultados: En la técnica transilíaca, los ángulos de abordaje axial y coronal fueron significativamente menores en 13,5° (IC 95% -15,5;-11,5; p<0,001) y 13,2º (IC 95% -15,3;-11,1); p<0,001 ), respectivamente, el ángulo de aproximación sagital aumentó significativamente en 5,4º (IC 95% 1,8,8,9; p = 0,008), y el AP CPR fue significativamente mayor (MD 0,16; IC 95% 0,12,0,20; p <0,001). El porcentaje del cage que cruzaba la línea media en AP era mayor en un 31,6% (IC 95% 19,8,43,4; valor p <0,001). Se mantuvo la integridad de las placas vertebrales, las articulaciones facetarias, las articulaciones sacroilíacas, el ligamento iliolumbar y las raíces de L5 y S1. Conclusión: La iLIF transilíaca L5S1 es una técnica quirúrgica viable. Permite colocar el cage más centrado en el plano coronal sin comprometer la posición anterior en el plano sagital. Se preservó la integridad de las principales estructuras anatómicas en riesgo. Nivel de evidencia III: Estudio de casos y controles.

Metaphyseal sleeves in revision total knee arthroplasties: Computational analysis of bone remodeling.

BACKGROUND: Metaphyseal sleeves help maintain long term stability and reduce revision rate for aseptic loosening in total knee arthroplasty (TKA) revision. However, their performance regarding bone remodeling is still poorly known for the long term. This study aimed to investigate the impact of metaphyseal sleeves on the bone remodeling of the tibia. METHODS: Five finite element models of a female tibia with different implant configurations (regarding stem length and metaphyseal sleeve application) were developed. Loading conditions included joint reaction force, muscle, and tibia-fibula loads from 6 instances of the gait cycle. The bone remodeling model applied was adapted to the subject under analysis by selecting the bone remodeling parameters that best replicated the bone density distribution of the tibia estimated from the CT data. Changes in bone density after TKA were evaluated in 8 regions of interest. RESULTS: Global bone loss ranged from -31.16%, in 115 mm stemmed configurations, to -20.93%, in 75 mm stemmed configurations. Apart from the lateral and posterior regions in the proximal tibia, whose bone loss reduced and increased, respectively, due to the incorporation of a metaphyseal sleeve, changes in bone density were similar with and without a metaphyseal sleeve for each stem length. CONCLUSION: The results suggest that bone remodeling of the tibia is not critically affected by the incorporation of metaphyseal sleeves. Considering that sleeves are believed to present a favorable clinical outcome in stability and osseointegration, reducing the revision rate for aseptic loosening, their advantages seem to outweigh their disadvantages regarding bone remodeling.

Treatment options for the symptomatic post-meniscectomy knee.

PURPOSE: To provide a current review on the evidence for management of the symptomatic meniscus-deficient knee. METHODS: A literature review was performed detailing the natural history and origin of symptoms in a meniscus-deficient knee, in addition to strategies for non-surgical management, meniscus scaffolds, meniscus allograft transplantation (MAT), isolated cartilage repair, unloading osteotomies, meniscus prosthesis, and joint replacements which were revealed as treatment possibilities. RESULTS: Meniscus deficiency was recognized to lead to an early onset knee osteoarthritis (OA). A subset of patients develop post-meniscectomy syndrome: dull and nagging pain after a short pain-free interval subsequently to meniscectomy, which can be accompanied by transient effusions. Evidence for non-surgical management of post-meniscectomy knee pain is lacking. Two available meniscus scaffolds, indicated for symptomatic segmental meniscus deficiency, show pain relief at mid-term follow-up, and effect on joint preservation is unclear. MAT represents a durable solution for sub/total meniscus deficiency (80% survival at 10 years), but it is still considered a temporary solution for post-meniscectomy pain. MAT may also reduce the progression of OA. Isolated cartilage repair without a meniscus reconstruction is commonly performed, but better results were reported with preserved or reconstructed menisci. Osteotomies are used in the combination of misaligned knee and meniscus reconstruction or as pain solution for irreversible unilateral knee structural changes following a meniscectomy. Polycarbonate-urethane medial meniscus prosthesis is currently undergoing clinical trial. Joint replacements should be limited to later stages of post-meniscectomy OA. CONCLUSIONS: Post-meniscectomy pain syndrome and post-meniscectomy knee OA are common findings after meniscus resection. Short-term pain relief is provided by non-surgical management, mid-term pain relief by meniscus scaffolds, and long-term relief by MAT, though each has differing indications. In later stages, osteotomies and joint replacements are indicated. LEVEL OF EVIDENCE: IV.

Automated femoral landmark extraction for optimal prosthesis placement in total hip arthroplasty.

The automated extraction of anatomical reference landmarks in the femoral volume may improve speed, precision, and accuracy of surgical procedures, such as total hip arthroplasty. These landmarks are often hard to achieve, even via surgical incision. In addition, it provides a presurgical guidance for prosthesis sizing and placement. This study presents an automated workflow for femoral orientation and landmark extraction from a 3D surface mesh. The extraction of parameters such as the femoral neck axis, the femoral middle diaphysis axis, both trochanters and the center of the femoral head will allow the surgeon to establish the correct position of bony cuts to restore leg length and femoral offset. The definition of the medullary canal endosteal wall is used to position the prosthesis' stem. Furthermore, prosthesis alignment and sizing methods were implemented to provide the surgeon with presurgical information about performance of each of the patient-specific femur-implant couplings. The workflow considers different commercially available hip stems and has the potential to help the preoperative planning of a total hip arthroplasty in an accurate, repeatable, and reliable way. The positional and orientation errors are significantly reduced, and therefore, the risk of implant failure and subsequent revision surgery are also reduced.

Biomechanical analysis of the tibial tray design in TKA: comparison between modular and offset tibial trays.

PURPOSE: The aim of this work was to develop a computational biomechanical study to compare the performance of tibial trays with different offsets for a total knee arthroplasty. The goal was to investigate whether the offset tibial tray shifts the bone stress distribution, influencing the clinical outcome. METHODS: Three geometric models were developed for the intact tibia bone: one considering a standard tibia case and the other two reproducing tibias with a medial or a lateral offset of the metaphysis. Appropriate prosthetic components were assembled in the bone for the aforementioned cases. The finite element method was used to obtain the mechanical stress distribution for the models, and the stress shielding effect due to the prosthesis was analysed. RESULTS: The obtained results revealed that the offset cases are subjected to higher stresses than the standard case. These values can be two times superior to the ones verified in a standard case. The stress shielding effect was confirmed along all the analysed paths, except near the stem's end in some areas. CONCLUSION: The higher stresses registered can originate lower clinical outcomes in the offset cases. These findings can be an important beginning to understand whether better bone stress distribution could be achieved in deformity correction with associated osteotomies instead of offsetting.

Tratamiento quirúrgico de la seudoartrosis diafisaria de húmero: resultados de un estudio multicéntrico

Se realizó un estudio multicéntrico retrospectivo sobre 69 pacientes que habían desarrollado seudoartrosis aséptica de húmero, y se analizaron los resultados del tratamiento quirúrgico. Los pacientes fueron evaluados entre los años 1971 y 1995. La edad media era de 48 años, 36 eran mujeres y 33 hombres. El tipo más frecuente de fractura fue A3 de la clasificación AO. Diez pacientes tenían fracturas expuestas, 17 presentaban lesiones nerviosas asociadas y 15 teníanotras fracturas asociadas. El tratamiento inicial de la fractura fue conservador en 34 pacientes y quirúrgico en 35. El tiempo medio de latencia entre el trauma inicial y el tratamiento quirúrgico de la fractura fue de 7,2 días. El tipo de callo formado fue atrófico en 52 seudoartosis e hipertrófico en 17. El tratamiento quirúrgico inicial de la seudoartrosis consistió en: placa y tornillos en 36 pacientes, enclavado endomedular en 15, fijación externa en 11, haz de Hackethal en 6 y sólo tornillos en 1. Se utilizó autoinjerto de esponjosa en 36 pacientes, injerto vascularizado de peroné en 1 y aloinjerto en 4. Se logró consolidación de la seudoartrosis en 64 de los 69 pacientes. El número medio de tratamientos quirúrgicos efectuados para lograr la consolidación fue de 1,5 por paciente con un rango de 1 a 4. Cuando utilizamos placa y tornillos se logró consolidación después del primer procedimiento en el 80 por ciento de los casos contra el 63 por ciento de los tratados con clavos endomedulares. No encontramos diferencia significativa en el tiempo medio de consolidación entre la seudoartosis atrófica e hipertrófica. La media de tiempo transcurrido entre el último procedimiento quirúrgico y la consolidación radiológica fue de 4,1 meses. Como conclusión creemos que el tratamiento óptimo de la seudoartrosis de la diáfisis del húmero es la fijación interna con placa a compresión más aporte de injerto óseo