Anterior corpectomy via the mini-open, extreme lateral, transpsoas approach combined with short-segment posterior fixation for single-level traumatic lumbar burst fractures: analysis of health-related quality of life outcomes and patient satisfaction.

OBJECTIVE: The authors present clinical outcome data and satisfaction of patients who underwent minimally invasive vertebral body corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach and posterior short-segment instrumentation for lumbar burst fractures. METHODS: Patients with unstable lumbar burst fractures who underwent corpectomy and anterior column reconstruction via a mini-open, extreme lateral, transpsoas approach with short-segment posterior fixation were reviewed retrospectively. Demographic information, operative parameters, perioperative radiographic measurements, and complications were analyzed. Patient-reported outcome instruments (Oswestry Disability Index [ODI], 12-Item Short Form Health Survey [SF-12]) and an anterior scar-specific patient satisfaction questionnaire were recorded at the latest follow-up. RESULTS: Twelve patients (7 men, 5 women, average age 42 years, range 22-68 years) met the inclusion criteria. Lumbar corpectomies with anterior column support were performed (L-1, n = 8; L-2, n = 2; L-3, n = 2) and supplemented with short-segment posterior instrumentation (4 open, 8 percutaneous). Four patients had preoperative neurological deficits, all of which improved after surgery. No new neurological complications were noted. The anterior incision on average was 6.4 cm (range 5-8 cm) in length, caused mild pain and disability, and was aesthetically acceptable to the large majority of patients. Three patients required chest tube placement for pleural violation, and 1 patient required reoperation for cage subsidence/hardware failure. Average clinical follow-up was 38 months (range 16-68 months), and average radiographic follow-up was 37 months (range 6-68 months). Preoperative lumbar lordosis and focal lordosis were significantly improved/maintained after surgery. Patients were satisfied with their outcomes, had minimal/moderate disability (average ODI score 20, range 0-52), and had good physical (SF-12 physical component score 41.7% ± 10.4%) and mental health outcomes (SF-12 mental component score 50.2% ± 11.6%) after surgery. CONCLUSIONS: Anterior corpectomy and cage placement via a mini-open, extreme lateral, transpsoas approach supplemented by short-segment posterior instrumentation is a safe, effective alternative to conventional approaches in the treatment of single-level unstable burst fractures and is associated with excellent functional outcomes and patient satisfaction.

Can a novel rectangular footplate provide higher resistance to subsidence than circular footplates? An ex vivo biomechanical study.

STUDY DESIGN: Ex vivo biomechanical evaluation using cadaveric vertebral bodies. OBJECTIVE: To compare the subsidence characteristics of a novel rectangular footplate design with a conventional circular footplate design. SUMMARY OF BACKGROUND DATA: Cage subsidence is a postoperative complication after reconstruction of corpectomy defects in the thoracolumbar spine and depends on factors, such as bone quality, adjunctive fixation, and the relationship between the footplate on the cage and the vertebral body endplate. METHODS: Twenty-four cadaveric vertebrae (T12-L5) were disarticulated, potted in a commercial resin, loaded with either a circular or a rectangular footplate, and tested in a servo hydraulic testing machine. Twelve vertebral bodies were loaded with a circular footplate, and after subsidence the same vertebral bodies were loaded with a rectangular footplate. The second set of 12 vertebral bodies was loaded with a rectangular footplate only. Force-displacement curves were developed for the 3 groups, and the ultimate load to failure and stiffness values were calculated. RESULTS: The ultimate load to failure with the circular footplate was 1310 N (SD, 482). The ultimate load to failure with a rectangular footplate with a central defect and without a central defect was 1636 N (SD, 513) and 2481 N (SD, 1191), respectively. The stiffness of the constructs with circular footplate was 473 N/mm (SD, 205). The stiffness of the constructs with a rectangular footplate with a central defect and without a central defect was 754 N/mm (SD, 217) and 1054 N/mm (SD, 329), respectively. CONCLUSION: A rectangular footplate design is more resistant to subsidence than a circular footplate design in an ex vivo biomechanical model. The new design had higher load to failure even in the presence of a central defect. These findings suggest that rectangular footplates may provide better subsidence resistance when used to reconstruct defects after thoracolumbar corpectomy.

Biomechanical evaluation of pediatric anterior cruciate ligament reconstruction techniques.

BACKGROUND: Anterior cruciate ligament (ACL) reconstruction rates in skeletally immature patients have risen recently because of increased injury frequency combined with growing awareness of the importance of treating them in an acute setting. Concerns over potential growth disturbances caused by traditional tunnel placement have prompted the description of several partial and complete physeal-sparing techniques. HYPOTHESIS: Native knee kinematics will most closely be restored by the all-epiphyseal technique because it best re-creates the intra-articular ACL anatomy. STUDY DESIGN: Controlled laboratory study. METHODS: Six cadaveric knees were subjected to static anteroposterior, varus, and internal rotation forces at 0°,15°, 30°, 45°, 60°, and 90° of flexion. Displacement and rotation of the tibia with respect to the femur were measured in the intact knee, after ACL disruption, and again after ACL reconstruction using all-epiphyseal, transtibial over-the-top, and iliotibial band physeal-sparing techniques. RESULTS: Peak anteroposterior translation in the ACL intact and deficient states was 2.8 ± 1.4 mm and 7.2 ± 2.7 mm, respectively, at 30°. The all-epiphyseal reconstruction had a peak translation of 5.1 ± 2.3 mm at 30°, and the transtibial over-the-top reconstruction had a peak of 4.8 ± 1.8 mm at 30°, both significantly greater than the ACL intact state. The iliotibial band technique had a peak anteroposterior translation of 1.7 ± 1.1 mm at 45°, which was significantly less than the ACL-deficient state. Internal rotation was significantly increased in the all-epiphyseal reconstruction compared with the ACL intact state and significantly decreased at all flexion angles except 0° in the iliotibial band reconstruction. The only technique to affect varus rotation was the iliotibial band reconstruction, which significantly decreased varus rotation from the ACL-deficient state at flexion angles greater than 30°. CONCLUSION: All physeal-sparing reconstruction techniques restored some stability to the knee. The iliotibial band reconstruction best restored anteroposterior stability and rotational control, although it appeared to overconstrain the knee to rotational forces at some flexion angles. CLINICAL RELEVANCE: This study provides orthopaedic surgeons with objective knee kinematic data to help guide them in making more informed decisions on the optimal technique for ACL reconstruction in skeletally immature patients.