Osteotomy Templates Research Articles

Three-dimensional printing-based personalized limb salvage and reconstruction treatment of pelvic tumors.

The treatment of pelvic tumors is widely recognized to be challenging. The purpose of this study was to evaluate the efficacy of personalized three-dimensional (3D) printing-based limb salvage and reconstruction treatment for pelvic tumors. Twenty-eight pelvic tumor patients were enrolled. 3D printing lesion models and osteotomy templates were prepared for surgery planning, prosthesis design, and osteotomy assistance during surgery. 3D printing-based personalized pelvic prostheses were manufactured and used in all 28 patients. Follow-up of postoperative survival, prosthesis survival, imaging examinations, and Musculoskeletal Tumor Society (MSTS) lower limb functional scores were carried out. The mean follow-up period was 32.2 months, during which 16 patients had disease-free survival, 3 survived with the disease, and 9 died. The prostheses were stable, and the mean offset of the center of rotation was 5.48 mm. The prosthesis-bone interface showed good integration. For the 19 surviving patients, the mean MSTS lower limb functional score was 23.2. Postoperative complications included superficial infection in six patients and hip dislocation in three patients. Personalized 3D printing-based limb salvage and reconstruction was an effective treatment for pelvic tumors. Our patients achieved good early postoperative efficacy and functional recovery.

3D camera-based markerless navigation system for robotic osteotomies

Abstract A markerless system for the registration of a bone’s pose is presented which reduces the setup time and the damage to the bone to a minimum. For the registration, a particle filter is implemented which is able to estimate a bone’s pose using depth images. In a phantom study, the pose of 3D-printed bones has been estimated at a rate of 90 Hz and with a precision of a few millimeters. The particle filter is stable under partial occlusions and only diverges when the bone is fully occluded. During a cadaver study, the preoperatively planned cutting edges have been projected as augmented reality (AR) templates onto the hip bones of five cadavers. By cutting manually along the AR templates, surgeons were able to extract ten transplants in the same time as with conventional osteotomy templates. Using the presented navigation system can save hours spent on the construction and production of conventional templates. In conclusion, this work represents one step towards a broader acceptance of robotic osteotomies.

Digital planning workflow for partial maxillectomy using an osteotomy template and immediate rehabilitation of maxillary Brown II defects with prosthesis.

There is increasing evidence of benefits for the rehabilitation of Brown II defects with prosthesis in surgery. However, the current literature is sparse for maxillary tumour resection using osteotomy templates. To assess the accuracy of maxillectomy using a custom fabricated osteotomy template and to evaluate the prosthesis for surgical accuracy, appearance and functioning (speech, swallowing and occlusal force). Ten patients with Brown II defects caused by tumour resection were treated with precise partial maxillectomy using an osteotomy template. The immediate rehabilitation of the Brown II defect was completed with a prefabricated prosthesis. The post-operative three-dimensional images and the pre-operative virtual images were superimposed, and average deviation and maximum deviation were calculated. Speech intelligibility, swallowing, appearance and University of Washington Quality of Life Questionnaire (UW-QoL) were examined at 1, 3 and 6months after surgery. Occlusal force was examined post-operatively at 6months. The maximum deviation between the actual and virtual surgery was 5.12±0.44mm, with an average of 1.02±0.17mm. Speech intelligibility, swallowing and UW-QoL improved significantly (P<.05) after wearing the prosthesis. The recovery index of the occlusal force on the affected side was 20.19%-32.28%. The skewed degree of the mouth corner, the difference in the height of the left and right lips, the maximum deviation distance and the change area volume decreased significantly (P<.05). The precise rehabilitation of maxillary Brown II defects can be achieved using a prosthesis fabricated with an osteotomy template. The prosthesis restored appearance and functional capabilities (such as speech and occlusal force).

Computer-aided modification of Reverdin osteotomy template for hallux valgus

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. Key words: Imaging, three-dimensional; Rapid prototyping; Clubfoot; Anatomy

Surgical treatment for shepherd's crook deformity in fibrous dysplasia: THERE IS NO BEST, ONLY BETTER.

The optimal strategy for shepherd's crook deformity correction remains technically challenging. In particular, it is difficult to performan accurate osteotomy based on the pre-operative correction plan. Moreover, the choice of ideal hardware remains unclear. In addition, when combined with the deformity of knee joint, the sequence of deformity correction is another overlooked factor when making a correction strategy. From February 2012 to March 2014, we retrospectively examined a cases series in our department involving the creation of three-dimensional (3D) printing osteotomy templates and inner fixation for shepherd's crook deformity in fibrous dysplasia. A total of ten patients of shepherd's crook deformity were enrolled in this study. The neck shaft angle was corrected from a mean value of 88.1° (range, 73-105°) pre-operatively to a mean value of 128.5° (range, 120-135°) post-operatively; no marked loss in the value was observed (mean, 123.7°; range, 115-130°) at the final follow-up. In addition, compared with patients using dynamic hip screw (DHS), longer operation time and additional blood loss were recorded in patients using intramedullary nail (IN). Moreover, after correction of shepherd's crook deformity, two patients were observed more predominant on their pre-existing valgus knee deformity. 3D printing osteotomy templates facilitate the correction of shepherd's crook deformity. Dynamic hip screw (DHS), combined with polymethylmethacrylate (PMMA) augmentation, yields excellent outcomes and ensures easy placement and non-intramedullary manipulation, lower bleeding volume, and reduced operation time. Prior to the correction of shepherd's crook deformity, the mechanical axis of the lower limb should be carefully examined, and any evidence of valgus knee deformity should be addressed in advance.

Three-Dimensional Planning and Use of Individualized Osteotomy-Guiding Templates for Surgical Correction of Kyphoscoliosis: A Technical Case Report

We have described the use of 3-dimensional (3D) virtual planning and 3D printed patient-specific osteotomy templates in the surgical correction of a complex spinal deformity. Pedicle subtraction osteotomies (PSOs) for the correction of severe spinal deformities are technically demanding procedures with a risk of major complications. In particular, operations of the severely deformed spine call for new, more precise, methods of surgical planning. The new 3D technology could result in new possibilities for the surgical planning of spinal deformities. We present the case of severe congenital kyphoscoliosis in a young girl with skeletal dysplasia. A closing wedge-extended PSO was 3D virtual planned using medical computer design software. After the optimal 3D-wedge procedure was planned, individualized osteotomy-guiding templates were designed for translation of the planned PSO to the surgical procedure. During surgery, the PSO was performed using the osteotomy templates. Successful correction of the kyphoscoliosis was realized. The kyphosis was successfully reduced using a wedge-shaped extended PSO using preoperative 3D virtual planning, assisted by 3D-printed individualized osteotomy-guiding templates. In addition to direct translation of the planned PSO for surgery, the 3D planning also facilitated a detailed preoperative evaluation, greater insight into the case-specific anatomy, and accurate planning of the required correction.

Locally Affine Diffeomorphic Surface Registration and Its Application to Surgical Planning of Fronto-Orbital Advancement.

Metopic craniosynostosis is a condition caused by the premature fusion of the metopic cranial suture. If untreated, it can result into brain growth restriction, increased intra-cranial pressure, visual impairment, and cognitive delay. Fronto-orbital advancement is the widely accepted surgical approach to correct cranial shape abnormalities in patients with metopic craniosynostosis, but the outcome of the surgery remains very dependent on the expertise of the surgeon because of the lack of objective and personalized cranial shape metrics to target during the intervention. We propose in this paper a locally affine diffeomorphic surface registration framework to create an optimal interventional plan personalized to each patient. Our method calculates the optimal surgical plan by minimizing cranial shape abnormalities, which are quantified using objective metrics based on a normative model of cranial shapes built from 198 healthy cases. It is guided by clinical osteotomy templates for fronto-orbital advancement, and it automatically calculates how much and in which direction each bone piece needs to be translated, rotated, and/or bent. Our locally affine framework models separately the transformation of each bone piece while ensuring the consistency of the global transformation. We used our method to calculate the optimal surgical plan for 23 patients, obtaining a significant reduction of malformations (p < 0.001) between 40.38% and 50.85% in the simulated outcome of the surgery using different osteotomy templates. In addition, malformation values were within healthy ranges (p > 0.01).

Application of the digital osteotomy template in the mandibular angle osteotomy

To investigate the application of the digital osteotomy template in the mandibular angle osteotomy,so as to increase the precision and symmetry of the osteotomy. 8 cases were included in our study (female,average age 25.5).The CT data (DICOM format) were reformatted into 3D images using 3D imaging software (ProPlan).The osteotomy lines were designed on digital 3D theoretical model with ProPlan.Then the statistics of the ostectomy were imported into GeoMagic in the form of STL file to design the 3D osteotomy template.The osteotomy template was fabricated with FDA certificated PLA through RP machine. During operation,the template was inserted into operation area to guide the osteotomy.A line was drawn along the edge of ostectomy plate with a grinding ball and osteotomy was done along the curvilinear line using a goose saw. The removed bone proved to be highly matched with the template.All the post-operative results were satisfactory.There were no complications such as fracture,life-threatening hemorrhage and infection.The post-operative measurement showed good symmetry. With the guidance of osteotomy templates,the surgeon can perform the osteotomy in an accurate way.The precision and symmetry of the osteotomy are greatly improved.

Measurement of rotational deformity: using a smartphone application is more accurate than conventional methods

We assessed the accuracy of three different methods measuring the angle between two fixed Kirschner wires for the potential purpose of determining correction during rotational osteotomy of long bones. Thirty-one orthopaedic consultants and registrars were prospectively asked to measure the angle between two fixed Kirschner wires in four saw bones models using three different techniques: visual estimation (VE), osteotomy templates (OT), and a contemporary smartphone (iPhone4; SP) with its gyroscopic function. These three methods were compared with the value obtained by computed tomography (CTV), which we considered the preferred value. For the pooled data for all four bone models, the mean difference of the VE compared with the CTV was 5.4° ± 5.3°; the mean difference of the OT compared with the CTV was 2.9 ± 3.8°; and the mean difference of the SP compared with the CTV was 0.8 ± 0.9°. Using the pooled data, the difference between using each of these methods was highly significant, as demonstrated by the one-way analysis of variance across groups (P ≤ 0.001). In addition, for the pooled data the independent t-test between each pair of the three methods (VE and OT, VE and SP, and OT and SP) also demonstrated these differences were highly significant (P ≤ 0.001) for all three comparisons. In this study, the number of years of orthopaedic experience did not significantly influence the ability of individual test subjects. Measurement of a rotational deformity using a SP app was significantly more accurate and consistent than both VE and OT. We believe the currently available SP technology provides orthopaedic surgeons with a significantly better alternative method of determining the magnitude of rotational deformity when performing corrective osteotomies.

Beckenteilresektion (innere Hemipelvektomie) und endoprothetischer Ersatz bei hüftgelenksnahen Tumoren

Treatment of tumors of the pelvic girdle by resection of part or all of the innominate bone with preservation of the extremity. Implantation and stable fixation using a custom-made megaprosthesis to restore painless joint function and loading capacity. The surgical goal is to obtain a wide surgical margin and local tumor control. Primary bone and soft tissue sarcomas, benign or semi-malignant aggressive lesions, metastatic disease (radiation resistance and/or good prognosis). Limited life expectancy and poor physical status, extensive metastatic disease, persistent deep infection or recalcitrant osteomyelitis, poor therapeutic compliance, local recurrence following a previous limb-sparing resection, extensive infiltration of the neurovascular structures and the intra- and extrapelvic soft tissues. Levels of osteotomy are defined preoperatively by a CT-controlled manufactured three-dimensional 1:1 model of the pelvis. Using these data, the custom-made prosthesis and osteotomy templates are then constructed by the manufacturer. The anterior (internal, retroperitoneal) and posterior (extrapelvic, retrogluteal) aspects of the pelvis are exposed using the utilitarian incision surgical approach. The external iliac and femoral vessels are mobilized as they cross the superior pubic ramus. The adductor muscles, the rectus femoris and sartorius muscle are released from their insertions on the pelvis and the obturator vessels and nerve are transected. If the tumor extends to the hip joint, the femur is transected at a level distal to the intertrochanteric line to ensure hip joint integrity and to prevent tumor contamination. A large myocutaneous flap with the gluteus maximus muscle is retracted posteriorly. The pelvitrochanteric and small gluteal muscles are divided near their insertion in the upper border of the femur. To release the hamstrings and the attachment of the sacrotuberous ligament, the ischial tuberosity is exposed. After osteotomy using the prefabricated templates, the pelvis is released and the specimen is removed en bloc. The custom made prosthesis can either be fixed to the remaining iliac bone or to the massa lateralis of the sacrum. The released muscles are refixated on the remaining bone or the implant. Time of mobilization and degree of weight-bearing depends on the extent of muscle resection. Usually partial loading of the operated limb with 10kg for a period of 6-12weeks, then increased loading with 10kg per week. Thrombosis prophylaxis until full weight bearing. Physiotherapy and gait training. At follow-up, patients are monitored for local recurrence and metastases using history, physical examination, and radiographic studies. Between 1994 and 2008, 38consecutive patients with periacetabular tumors were treated by resection and reconstruction with a custom-made pelvic megaprosthesis. The overall survival of the patients was 58% at 5years and 30% at 10years. One or more operative revisions were performed in 52.6% of the patients. The rate of local recurrence was 15.8%. Deep infection (21%) was the most common reason for revision. In two of these cases (5.3%), a secondary external hemipelvectomy had to be performed. There were four cases of aseptic loosening (10.5%) in which the prosthesis had to be revised. Six patients had recurrent hip dislocation (15.8%). In four of them a modification of the inserted inlay and an implantation of a trevira tube had to be performed respectively. Peroneal palsy occurred in 6patients (15.8%) with recovery in only two. There were 4operative interventions because of postoperative bleeding (10.5%). The mean MSTS score for 12 of the 18living patients was 43.7%. In particular, gait was classified as poor and almost all patients were reliant on walking aids. However, most patients showed good emotional acceptance.

Accuracy of Intraoral Vertical Ramus Osteotomy With a Stereolithographic Template

Various modifications have been described to improve the accuracy in intraoral vertical ramus osteotomy (IVRO), but there was not a measurable facility to determine the osteotomy line. The purpose of this study was to evaluate the accuracy of the computer tomography (CT)-based osteotomy template on cadaver mandibles and to assess the outcome after IVRO correcting mandibular prognathism. Four human wet cadaver heads were subjected to a high-resolution multislice spiral CT scan. After the virtual osteotomies in the planning program, the individual osteotomy templates were produced by stereolithography. A stable and secure fit of the stereolithographic templates was achieved via the individual CT-based osteotomy template. The osteotomy lines were performed exactly as planned in the virtual osteotomies planning program. Similar sound outcome was also observed in the clinic. Use of the CT-based osteotomy templates is a safe method for osteotomy. It is rather convenient for vertical osteotomy in IVRO increasing the intraoperative accuracy and efficiency.

Application of computer-aided design osteotomy template for treatment of cubitus varus deformity in teenagers: A pilot study

Treatment of cubitus varus deformity from a malunited fracture is a challenge. Anatomically accurate correction is the key to obtaining good functional outcomes after corrective osteotomy. The aim of this study was to attempt to increase the accuracy of treatment by use of 3-dimensional (3D) computer-aided design. We describe a novel method for ensuring an accurate osteotomy method in the treatment of cubitus varus deformity in teenagers by means of 3D reconstruction and reverse engineering. Between January 2006 and May 2008, 12 male and 6 female patients with cubitus varus deformities underwent scanning with spiral computed tomography (CT) preoperatively. The mean age was 15.7 years, ranging from 13 to 19 years. Three-dimensional CT image data of the affected and contralateral normal bones of cubitus were transferred to a computer workstation. Three-dimensional models of cubitus were reconstructed by use of MIMICS software. The 3D models were then processed by Imageware software. An osteotomy template that best fitted the angle and range of osteotomy was "reversely" built from the 3D model. These templates were manufactured by a rapid prototyping machine. The osteotomy templates guide the osteotomy of cubitus. An accurate angle of osteotomy was confirmed by postoperative radiography. After 12 to 24 months' follow-up, the mean postoperative carrying angle in 18 patients with cubitus varus deformity was 7.3° (range, 5° to 11°), with a mean correction of 21.9° (range, 12° to 41°). The patient-specific template technique is easy to use, can simplify the surgical act, and generates highly accurate osteotomy in cubitus varus deformity in teenagers.

A New Arthroscopic Technique to Determine Anterior-Inferior Glenoid Bone Loss: Validation of the Secant Chord Theory in a Cadaveric Model

The accuracy of a previously described method using the glenoid bare spot (GBS) as a reference point was compared with a new method using the secant chord theory (SCT), which relies on the circular geometry of the inferior glenoid to calculate bone loss. In 7 embalmed cadaveric shoulders a digital image of the glenoid face was used to calculate the area of the best-fit circle of the inferior glenoid. Osteotomy templates from the 3-o'clock to 6-o'clock position were created to make a simulated anterior-inferior bone defect of 12.5% and 25% of the area of the circle. Measurements were taken with an arthroscopic probe from 2 simulated posterior portal positions (9 and 10 o'clock) by use of 2 techniques-SCT and GBS-in the intact, 12.5% loss, and 25% loss states. In the intact state, measurements showed a mean SCT loss of 4.1% and GBS loss of 4.4%. In the 12.5% loss state, mean percent bone loss with GBS was 23.1% compared with 14.8% with SCT (P = .0001) at the 10-o'clock portal and 22.2% compared with 15.9% (P = .006) at the 9-o'clock portal. In the 25% loss state, mean percent bone loss with GBS was 31.5% compared with 26.6% with SCT (P = .002) at the 10-o'clock portal and 30.4% compared with 28.9% (P = .48) at the 9-o'clock portal. The SCT is shown to be a more accurate method of determining glenoid bone loss in an arthroscopic model; however, additional mathematic calculations are necessary. As shown in the intact state, there is an inherent small error of approximately 4% when arthroscopically determining bone loss. The technique may aid the clinician in quantifying glenoid bone loss and help determine when bone augmentation may be advisable.