ABSTRACT
Objective To provide a method to modify accurately the Reverdin osteotomy template for hallux valgus using 3D reconstruction and printing.Methods From June 2015 to June 2016,11 patients (16 feet) with hallux valgus at our departments underwent weight-bearing X-ray examination and continuous spiral CT scanning of the feet.The outer turning angle of hallux averaged 33.50° ± 6.80°,the first intermetatarsal angle 12.20°± 2.90° and the distal metatarsal articular angle 15.20°± 2.60°.Their imaging Dicom data were imported into Materialise Mimics Innovation Suite v16.0 software for generation of 3D models of the pelvis which were then stored in stereolithography format and imported into Imageware 12 software.After optimal templates were reversely rebuilt to have the best angles and range for Reverdin osteotomy in the 3D models,they were manufactured by a rapid prototyping machine.The osteotomy templates were used in surgery to guide the osteotomy of hallux valgus.Correction of hallux valgus,bone union at the osteotomy sites and weight-bearing walk were observed postoperatively.Results Accurate angles of osteotomy were confirmed by postoperative radiography in all the 16 feet.Follow-ups for 6 to 12 months showed in the 16 feet a mean outer turning angle of hallux of 7.31 °±0.33° (from 5° to 11 °) and a mean correction of 21.92°± 4.8° (from 13° to 24°).Bone union was fine at the osteotomy sites and no pain was reported during weight-bearing walk.Conclusion 3D reconstruction and printing can produce a patient-specific template for accurate Reverdin osteotomy for hallux valgus,leading to increased contact area and fine union of the osteotomy ends.
ABSTRACT
Objective To explore the safe bone channels for transverse placement of sacroiliac screws via the second sacral vertebra in the fixation of longitudinal fracture of the sacrum by digital analysis and clinical observation.Methods Firstly,abdomen CT scanning was performed in 50 healthy adult volunteers.They were 30 males and 20 females,aged from 18 to 56 years (mean,34.6 years).After their CT images were transformed by software Materialise Mimics Innovation Suite 15.0,three-dimensional (3D) models of the pelvis were generated,stored in stereolithography format,and transferred into software Imageware 12.0.In the standard antero-posterior position,the sacrum was segmented and the points of 2D image coordinate geometric boundary were extracted to generate an optimal channel for transverse placement of sacroiliac screws via the second sacral vertebra.Secondly,we admitted 10 patients with longitudinal fracture of the sacrum.They were 7 men and 3 women,aged from 20 to 51 years (average,38.3 years).By Tile classification,4 cases were type B2 and 6 type C1.All the fractures were Denis region Ⅱ ones.Pubic ramus fracture was complicated in 3 cases.After traction reduction of the tibial tubercle was conducted for patients with obvious displacement,the optimal channel was calculated on the basis of the CT data.On the lateral images of the sacrum acquired before operation by C-arm fluoroscopy,the optimal channel for transverse placement of sacroiliac screws via the second sacral vertebra was located.After the skin was marked,2.5 mm Kirschner wire was drilled and the 6.0 mm hollow screws were fixated along the Kirschner wire.Postoperative CT scanning images and 3D reconstructed models were analyzed to validate the accuracy of screw placement.Results The projection of safety bone channel on the sagittal fluoroscopy of S2 vertebral body displayed an irregular water drop shape;the projection area in males (213.9 ± 52.4 mm2) was significantly larger than that in the females (171.6 ±49.6 mm2) (P ＜ 0.05).The average length of the channel in men (135.2 ± 12.9 mm) was significantly longer than that in women (121.1 ± 10.1 mm);the average diameter of the screw in men (10.2 ± 0.9 mm) was also significantly larger than that in women (9.1 ±0.8 mm) (P ＜ 0.05).The postoperative X-ray and CT scanning images showed satisfactory positions and lengths of the screws.The screw lengths averaged 98.2 mm;the operation time averaged 25.6 min.No nerve or vascular injury,loosening or breakage of the sacroiliac screws occurred in the patients.Follow-ups for 12 to 24 months revealed no other complications.Conclusion The safety channel for transverse placement of sacroiliac screws via the second sacral vertebra can be determined using the lateral 3D reconstruction images of the sacrum in preoperative planning,which facilitates the percutaneous transverse fixation of longitudinal fracture of the sacrum.
ABSTRACT
Objective To observe the clinical efficacy of minimally invasive percutaneous K-wire crossover fixation treating scaphoid fractures under C-arm.Methods From March 2011 to May 2014,20 patients with fresh scaphoid fractures had postoperative regular outpatient follow-up.Evaluation indicators included Cooney wrist scoring system,X-ray assessment of fracture healing,questionnaire survey of patient's subjective satisfaction at the final follow-up.Results All patients were followed up for 4 to 18 months,the mean follow-up time being 10 months.Postoperative X-ray showed all cases achieved bony union within 8 to 12 weeks,an average of 9.2 weeks.The questionaire resuits of patient's subjective satisfaction showed that general feeling of treatment in 2 cases,relatively satisfied in 2 cases,greatly satisfied in remaining 16 patients at the final follow-up.According to the postoperative Cooney wrist score,excellent in 8 cases,good in 10 cases,fair in 2 cases,the overall satisfactory rate was 90.2％.There were not pin tract infection,nonunion,malunion,avascular necrosis of scaphoid and other complications.2 cases showed that wrist pain during weight-bearing activities and weather getting cold,minor limitations of wrist function and degree of activity,grip strength slightly worse than the contralateral.Conclusions Minimally invasive percutaneous K-wire crossover fixation under C-arm combined with postoperative plaster external fixation properly can attain good clinical results in the treating of scaphoid fractures and worthy of further promotion.