Patient-specific Guides Research Articles

Computer Assisted Guided Placement of IMF Screws in Craniomaxillofacial Trauma: An Evolving Technique

Intermaxillary fixation (IMF) screws have been introduced into maxillofacial trauma practice to reduce operation time and the complications associated with the placement of wire ligatures around teeth. Wires continue to be used to secure arch bars to teeth, form eyelets and long ligatures prior to putting a patient into maxillomandibular fixation (MMF). The application of wires to dental arches may result in sharp injuries to the operator, whereas injury to roots and nerves may arise from incorrect positioning of IMF screws in the jaws. The purpose of this technical note is to demonstrate how 3D patient specific (PS) surgical guides can be planned and fabricated to assist in the safe placement of IMF screws in the maxilla and mandible. It is proposed that PS IMF screw guides can be further developed to incorporate removable spoons and semi-circular access ports that not only facilitate safe screw placement but allow the guide to remain in position until all screw are secured. The potential benefits of PS IMF surgical guides include diminished risk of injury to facial structures and reduced operation time. The technique also lends itself to the placement of IMF screws via a robotic arm contributing to a safer operating environment for the maxillofacial surgery team.

Technique tip: 3D printing surgical guide for pes cavus midfoot osteotomy

BackgroundPes cavus can be defined as an abnormal elevation of the longitudinal arches, which is often secondary to a muscle imbalance. This deformity affects the foot’s three dimensions (3D) and our osteotomies are usually planned on a lateral (two-dimension) X-ray. Are we really considering all the spatial components of the deformity? The aim of this study is to present a technique tip to identify the apical plane of the pes cavus deformity and perform a midfoot dorsal-based wedge resection osteotomy by using customized 3D printed surgical guides. MethodsThree patients underwent the presented technique, all for the indication of symptomatic neuromuscular pes cavus with both anterior and posterior deformity. Results3D-printed patient-specific guides help the surgeon to minimize human error, improving intraoperative accuracy, while reducing surgical time and intraoperative X-ray exposure. ConclusionsClosing wedge midfoot osteotomy to correct anterior pes cavus may be an interesting indication to use customized 3D printed surgical guides.

Comparison of Clinical Outcomes After Transforaminal Interbody Fusion Using Cortical Bone Trajectory versus Percutaneous Pedicle Screw Fixation

The study aim was to compare clinical outcomes between patients undergoing transforaminal lumbar interbody fusion (TLIF) using percutaneous pedicle screw (PPS) and cortical bone trajectory (CBT) by a single surgeon. This was a retrospective matched-cohort study of 77 patients (mean age, 71.7 years; 56% female) who underwent TLIF using CBT or PPS. Thirty-nine consecutive patients in the CBT group and 38 patients in the PPS group were matched for age, sex, and fused levels. All CBT screws were inserted by using a three-dimensional patient-specific guide (MySpine MC, Medacta). Perioperative outcomes of operative time, estimated blood loss, numeric rating scale scores, and serum concentration of creatine kinase were compared between the 2 groups. At 1 year postoperatively, clinical outcomes and radiographic outcomes, including cage subsidence, screw loosening, and fusion rates, were compared between the 2 groups. The numeric rating scale scores on postoperative days 3 and 7 and serum creatine kinase levels on postoperative days 1 and 3 were significantly lower in the CBT group than in the PPS group (all P < 0.005). There were no significant intergroup differences in operation time and estimated blood loss. At postoperative 1 year, there were no significant differences in cage subsidence, screw loosening, and fusion rates between the CBT group and PPS group. Clinical outcomes were equivalent between the 2 groups. The CBT technique using three-dimensional patient-specific guides resulted in lower perioperative pain and quicker recovery after surgery, which suggests that CBT is a less invasive procedure than PPS.

Custom-made 3D printed patient specific guides (PSG) improves component axial alignment in total knee arthroplasty (TKA)

BackgroundUsage of Patient Specific Instrumentation (PSI) or Patient Specific Guides (PSG) in TKA has evolved rapidly in the past decade. Restoration of Mechanical axis in TKA is vital to achieve good functional outcome and long term implant survival. We carried out a comparative study to assess the efficacy of PSG in achieving neutral axial alignment and its impact on early functional outcomes compared to Conventional Instrumentation (CI). MethodsPatients eligible as per study design (n = 100) undergoing TKA were randomized and divided in two equal groups which were matched in baseline demographics and clinical profile. All the patients in the PSG group (n = 50) and conventional instrumentation (CI) group (n = 50) underwent TKA with same implant. Pre-operative CT scans done as per specified protocol to acquire image data for 3D printing PSG. Duration of surgery and post-operative Hip-Knee-Ankle (HKA) angles achieved in the two groups was compared. Post-operative functional outcomes were assessed using WOMAC scores. ResultsThere was statistically significant difference in the mean post-operative axial alignment achieved between the two groups (p = 0.041). Outliers (180 ± 3 deg) of HKA angle were more in the CI Group (p = 0.007). There was no difference in functional outcomes between the two groups at one year. Duration of surgery was significantly less in PSG Group (p < 0.001). Conclusion3D printed PSG are superior in achieving neutral HKA axis as compared to CI in TKA. Better axial alignment of TKA components does not correlate with better patient reported functional outcomes. PSG use significantly reduces surgical time.

Comparison between Novice and Experienced Surgeons Performing Corrective Osteotomy with Patient-Specific Guides in Dogs Based on Resulting Position Accuracy.

Corrective osteotomy has been applied to realign and stabilize the bones of dogs with lameness. However, corrective osteotomy for angular deformities requires substantial surgical experience for planning and performing accurate osteotomy. Three-dimensional printed patient-specific guides (3D-PSGs) were developed to overcome perioperative difficulties. In addition, novices can easily use these guides for performing accurate corrective osteotomy. We compared the postoperative results of corrective osteotomy accuracy when using 3D-PSGs in dogs between novice and experienced surgeons. We included eight dogs who underwent corrective osteotomy: three angular deformities of the radius and ulna, three distal femoral osteotomies, one center of rotational angle-based leveling osteotomy, and one corrective osteotomy with stifle arthrodesis. All processes, including 3D bone modeling, production of PSGs, and rehearsal surgery were carried out with computer-aided design software and a 3D-printed bone model. Pre- and postoperative positions following 3D reconstruction were evaluated by radiographs using the 2D/3D registration technique. All patients showed clinical improvement with satisfactory alignment and position. Postoperative accuracy evaluation revealed no significant difference between novice and experienced surgeons. PSGs are thought to be useful for novice surgeons to accurately perform corrective osteotomy in dogs without complications.

Patient-specific plate for navigation and fixation of the distal radius: a case series

PurposeCorrective osteotomy of a malunited distal radius conventionally relies on 2D imaging techniques for alignment planning and evaluation. However, this approach results in suboptimal bone repositioning, which is associated with poor patient outcomes. In this case series, we evaluate the use of novel patient-specific plates (PSPs), which feature navigation and fixation of bone segments as preoperatively planned in 3D.MethodsTen participants with distal radius malunion underwent CT scans for preoperative alignment planning. Patient-specific guides and plates were designed, 3D-printed, and sterilized for use in corrective surgery of the distal radius. Pre- and postoperative results were compared in regard to clinical, functional, and radiographic outcomes.ResultsThe application of a PSP was successful in 7 of the 10 cases. After treatment, the residual alignment error was reduced by approximately 50% compared with conventional treatment. The use of PSPs reduced pain significantly. Pre- and postoperative results were pooled and demonstrated significant correlations between: (1) pain and malpositioning, (2) the range of pro- and supination motion, the MHOQ score, the EQ-5D-5L score and dorsovolar angulation, and (3) MHOQ score and proximodistal translation.ConclusionThe correlation between malalignment and MHOQ score, EQ-5D-5L score, pain, and range of motion shows that alignment should be restored as well as possible. Compared to the conventional approach, which relies on 2D imaging techniques, corrective osteotomy based on 3D preoperative planning and intraoperative fixation with a PSP has been shown to improve bone alignment and reduce pain.Level of evidenceIV.

The Development of Novel 2-in-1 Patient-Specific, 3D-Printed Laminectomy Guides with Integrated Pedicle Screw Drill Guides

To determine if 2-in-1 patient-specific laminectomy and drill guides can be safely used to perform laminectomy and pedicle screw insertion. This was a cadaveric study designed to test novel 2-in-1 patient-specific laminectomy guides, with modular removable pedicle screw drill guides. Three-dimensional (3D) printing has not been applied to laminectomy. This cadaveric study tests novel 2-in-1 patient-specific laminectomy guides, with modular removable pedicle screw drill guides. Computed tomography (CT) scans of 3 lumbar spines were imported into 3D Slicer. Spinal models and patient-specific guides were created and 3D printed. The bones were cleaned to visualize and record the under surface of the lamina during laminectomy. Pedicle screws and laminectomies were performed with the aid of patient-specific guides. CT scans were performed to compare planned and actual screw and laminectomy positions. Thirty screws were inserted in 15 lumbar vertebrae by using the integrated 2-in-1 patient-specific drill guides. There were no cortical breaches on direct examination, or on postoperative CT. Digital video analysis revealed the burr tip did not pass deep to the inner table margin of the lamina in any of the 30 laminectomy cuts. Average surgical time was 4 minutes and 46 seconds (standard deviation, 1 min 38 sec). This study has explored the development of novel 2-in-1 patient-specific, 3D-printed laminectomy guides with integrated pedicle screw drill guides, which are accurate and safe in the laboratory setting. These instruments have the potential to simplify complex surgical steps, and improve accuracy, time, and cost.

Application of Virtual Planning for Three-Dimensional Guided Maxillofacial Reconstruction of Pruzansky-Kaban III Hemifacial Microsomia Using Custom Made Fixation Plate.

Pruzansky-Kaban III hemifacial microsomia (HFM) is a rare congenital facial deformity, and it is challenging to reconstruct the facial appearance. The aim of the present study was to describe a technique of application of virtual planning for three-dimensional (3D) guided maxillofacial reconstruction of Pruzansky-Kaban III HFM using custom made fixation plate. With the help of 3D models, a preoperative virtual planning and surgical simulation were performed. Computer-aided design/computer-aided manufacture (CAD/CAM) patient customized guides and custom fixation plates were designed to reconstruct the maxillofacial skull intraoperatively. Assessment was achieved through evaluation of the postoperative effects, such as imaging, facial appearance recovery and operation time. Five patients with Pruzansky-Kaban III HFM were enrolled into this study. The results showed an exceptional accuracy between the preoperative virtual planning and the outcomes actually achieved postoperatively. Intraoperative measurements were no longer needed and the different surgical steps became more simple and easier. The total time was distributed as: 160 minutes for the surgical time, 40 minutes for preoperative virtual plan, and 80 minutes for designing the patient specific cutting guides and custom fixation plates. The operating time and tissue damage were reduced. All cases underwent uneventful healing without any complications. The technique of patient specific guides and custom fixation plates is a reliable method of conveying the virtual plan to the operative field with higher efficiency in patients with Pruzansky-Kaban III HFM.

Current concepts in anterior glenohumeral instability: diagnosis and treatment.

The glenohumeral joint is the most dislocated articulation, accounting for more than 50% of all joint dislocations. The reason behind shoulder instability should be investigated in detail for successful management, and the treatment plan should be individualized for all patients. Several classification systems have been proposed for glenohumeral instability. A physical exam is mandatory no matter what classification system is used. When treating patients with anterior shoulder instability, surgeons need to be aware of the critical size of the bone loss, which is commonly seen. The glenoid track concept was clinically adopted, and the measurement of the glenoid track for surgical decision-making is recommended. Detailed assessment of existing soft tissue injury to the labrum, capsule, glenohumeral ligaments, and rotator cuff is also mandatory as their presence influences the surgical outcome. Rehabilitation, arthroscopic repair techniques, open Bankart procedure, capsular plication, remplissage, Latarjet technique, iliac crest, and other bone grafts offer the surgeon different treatment options according to the type of patient and the lesions to be treated. Three-dimensional (3D) technologies can help to evaluate glenoid and humeral defects. Patient-specific guides are low-cost surgical instruments and can be used in shoulder instability surgery. 3D printing will undoubtedly become an essential tool to achieve the best results in glenohumeral instability surgery.

Orbitofrontal Reconstruction With a Three-Dimensional Titanium Patient-Specific Implant After Intraosseous Haemangioma Resection

Intraosseous hemangiomas are rare benign tumors that can develop in the skull. Orbitofrontal localization is uncommon. The complexity of orbitofrontal anatomy results in difficult reconstruction following trauma or tumoral resection. A 50-year-old woman with a right orbitofrontal intraosseous hemangioma was referred to our department. The authors decided to perform tumoral bone resection and orbitofrontal reconstruction using virtual surgical planning in collaboration with Materialize engineers (Materialise, Leuven, Belgium). Three cutting guides and a patient-specific 3-dimensional (3D) titanium implant were designed and manufactured in 3 weeks. Surgery was performed with a double surgical team composed of maxillofacial surgeons and neurosurgeons. No perioperative or post-operative complications occurred. Post-operatively, the patient was completely asymptomatic and clinical examination showed symmetrical and satisfactory facial morphology. Virtual surgical planning, design of patient-specific guides and manufacturing of implants make surgery easier and increase surgical precision. This technique is recommended for wide use in cases of oncological or complex trauma craniomaxillofacial reconstruction.

Patient Specific Guides in Total Knee Arthroplasty-Are They Accurate in Restoring Mechanical Alignment? A Prospective Clinical Series of 175 Cases

Background: Our study looked to see if patient specific guides in TKA restored mechanical alignment in patients with osteoarthritis. Materials and Methods: This prospective study measured the coronal alignment using long leg radiographs in 175 TKAs performed using patient specific cutting blocks. All patients underwent a posterior stabilizing TKA (Smith & Nephew GENESIS II) by the senior surgeon (WB) using Visionaire cutting blocks (based on pre-operative MRI studies). Results: The mechanical axis of the knee joint was measured using long leg radiographs taken six weeks post-operatively. There were no adverse intraoperative events. The coronal axis was restored to within 3° of neutral in 144 of 168 knees (85.7%). Conclusion: We conclude that patient specific instrumentation is accurate in restoring mechanical alignment in patients undergoing TKA.

Accuracy and Early Clinical Outcome After 3-Dimensional Correction of Distal Radius Intra-Articular Malunions Using Patient-Specific Instruments

To investigate the residual articular incongruity on computed tomography image data and the early clinical outcome of 3-dimensional planned and navigated intra-articular osteotomies of the distal radius. We conducted a retrospective analysis of intra-articular osteotomies executed between 2008 and 2016. We identified 37 patients (aged 26-73 years) and performed a combined intra-articular and extra-articular osteotomy on 20 patients. A preoperative 3-dimensional plan with the superimposed bone of the contralateral healthy side was performed in each case to analyze and execute the osteotomy by intraoperative navigation. The residual articular incongruity was assessed by quantification of the maximal stepoff in the coronal or sagittal computed tomography scans. Clinical outcome, including range of motion, grip strength, and return to work, was assessed after a minimum follow-up of 12 months and compared with preoperative measurements. On average, the preoperative intra-articular stepoff was 2.5 mm (±0.6 mm; range, 1.4-4.2 mm) and was significantly reduced to 0.8 mm (±0.2 mm) after surgery. After surgery, 30 patients had a stepoff less than 1 mm; in 7, a stepoff of 1.1 to 1.4 mm was measured. After 1 year, 22 had no pain, 9 had slight pain during heavy work, and 5 had moderate pain with no improvement compared with their preoperative status, although wrist strength and range of motion improved in all 37 patients. One patient underwent a secondary radioscapholunate arthrodeses owing to persistent pain despite a congruent joint with a small residual intra-articular stepoff (0.6 mm). Intra-articular osteotomies of the distal radius treated by 3-dimensional preoperative planning and patient-specific guides are an accurate technique to reduce articular incongruity to an average stepoff of 0.8 mm (range, 0.3-1.4 mm). The early clinical outcomes demonstrated overall reduction in pain and improvement of range of motion and grip strength in 36 of 37 patients. Therapeutic IV.

Computer-guided gap arthroplasty: a new approach to the execution of preplanned osteotomies for the treatment of bony ankylosis of the temporomandibular joint.

The purpose of this study was to assess the efficacy of 3-dimensional, printed, patient-specific guides to direct virtual gap arthroplasties that were designed for five patients with advanced unilateral ankylosis of the temporomandibular joint. The guides were used to mimic the intraoperative creation of five preplanned osteotomies, as well as simulating the width and depth of the bone cleavage. The accuracy of the devices in guiding the surgical simulation was assessed by superimposing the preoperative and postoperative computed tomographic scans. The devices were easily put in place with smooth uniform surgical bone cleavage, and favourable postoperative outcomes. The statistical analysis between the planned and surgical gaps, showed that the difference in dimensions was not significant (p=0.1018). The patient-specific gap arthroplasty was neither too near the skull base nor did it jeopardise the height of the mandibular ramus.

Computer navigation leads to more accurate glenoid targeting during total shoulder arthroplasty compared with 3-dimensional preoperative planning alone

Commercially available preoperative planning software is now widely available for shoulder arthroplasty. However, without the use of patient-specific guides or intraoperative visual guidance, surgeons have little in vivo feedback to ensure proper execution of the preoperative plan. The purpose of this study was to assess surgeons' ability to implement a preoperative plan in vivo during shoulder arthroplasty. Fifty primary shoulder arthroplasties from a single institution were retrospectively reviewed. All surgical procedures were planned using a commercially available software package with both multiplanar 2-dimensional computed tomography and a 3-dimensional implant overlay. Following registration of intraoperative visual navigation trackers, the surgeons (1 attending and 1 fellow) were blinded to the computer navigation screen and attempted to implement the plan by simulating placement of a central-axis guide pin. Malposition was assessed (>4 mm of displacement or >10° error in version or inclination). Data were then blinded, measured, and evaluated. Mean displacement from the planned starting point was 3.2± 2.0 mm. The mean error in version was 6.4° ± 5.6°, and the mean error in inclination was 6.6° ± 4.9°. Malposition was observed in 48% of cases after preoperative planning. Malposition errors were more commonly made by fellow trainees vs. attending surgeons (58% vs. 38%, P = .047). Despite preoperative planning, surgeons of various training levels were unable to reproducibly replicate the planned component position consistently. Following completion of fellowship training, significantly less malposition resulted. Even in expert hands, the orientation of the glenoid component would have been malpositioned in 38% of cases. This study further supports the benefit of guided surgery for accurate placement of glenoid components, regardless of fellowship training.

Accuracy and safety of cortical bone trajectory screw placement by an inexperienced surgeon using 3D patient-specific guides for transforaminal lumbar interbody fusion

Cortical bone trajectory (CBT) is an alternative method for pedicle screw insertion. However, identification of the optimal entry point and the direction of the CBT can be challenging for less-experienced surgeons. The purpose of this study was to evaluate the accuracy of the CBT screw placement by an inexperienced surgeon using a three-dimensional (3D) patient-specific guide for transforaminal lumbar interbody fusion (TLIF). Retrospective analysis of the data pertaining to 30 patients (128 screws) who underwent TLIF with CBT by an inexperienced surgeon using a 3D patient-specific guide (MySpine MC, Medacta) at a single center was performed. The accuracy of the CBT screw was graded into four groups (no perforation; Grade A, 0–2 mm; Grade B, 2–4 mm; and Grade C, > 4 mm). The accuracy of the CBT screw placement was 91% (116/128). Out of the 12 misplaced screws, Grade A was observed in 7 screws (5%), Grade B was observed in 3 screws (2%), and Grade C was observed in 2 screws (2%). There were no cases of medial pedicle wall perforation. The mean screw size was 5.95 ± 0.34 mm in diameter and 40.15 ± 2.83 mm in length. Note that, the accuracy of the CBT screws increased to 97% (83/86) over the first10 cases. Preoperative planning and 3D patient-specific guide enabled the use of longer and thicker screws and an optimal entry point. These results suggest the possibility of efficacy and safety in using 3D patient-specific guides for CBT screw placement by an inexperienced surgeon.

Porous metal wedge augments to address glenoid retroversion in anatomic shoulder arthroplasty: midterm update

Wedge-shaped porous metal augments were used to address bone deficiency in shoulder arthroplasty as part of a hybrid combination of high-density polyethylene, polymethyl methacrylatebone cement, and porous metal implant. This article presents an ongoing review of the use of the generically designed augments in the shoulder to address glenoid retroversion as part of anatomic total shoulder arthroplasty (aTSA). Seventy-five shoulders in 66 patients (23 women and 43 men, aged 42-85 years) with Walch grade B2 or C glenoids underwent porous metal glenoid augment (PMGA) insertion as part of aTSA. Patients underwent preoperative 3-dimensional (3D) templating; based on that planning, patients received either a 15° or 30° PMGA wedge (secured by screws to the native glenoid) to correct excessive glenoid retroversion before a standard glenoid component was implanted using bone cement. Neither patient-specific guides nor navigation were used. Intraoperative glenoid alignment was assessed using a reusable guide that referenced the anterior scapular neck. Patients were prospectively assessed using shoulder functional assessments (Oxford Shoulder Score [OSS], American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES], visual analogscale [VAS] pain scores, and forward elevation [FE]) preoperatively; at 3, 6, and 12 months postoperation; and yearly thereafter, with similar radiologic surveillance. Of the total consecutive series, 49 shoulders had a follow-up of greater than 24 months, with a median follow-up of 48 months (range: 24-87 months). For this cohort, median outcome scores improved for OSS (21 to 44), ASES (24 to 92), VAS (7 to 0), and FE (90° to 140°) from preoperative outcomes to the most recent review, respectively. Four patients died, but no others were lost to follow-up. Apart from 1 infection at 18 months postoperatively and 1 minor peg perforation, there were no complications, hardware failures, implant displacements, significant lucency, or posterior resubluxations. Radiographs showed good incorporation of the wedge augment, with correction of glenoid retroversion from median 22° (13° to 46°) to 4° (17° to anteversion 16°). All but 4 glenoids were corrected to within the target range (less than 10° retroversion), and only 2 glenoid components were implanted outside 15° of neutral glenoid version. The porous metal wedge-shaped augments effectively addressed posterior glenoid deficiency as part of aTSA for rotator cuff intact osteoarthritis, producing satisfactory clinical outcomes with no signs of impending future failure.

Preoperative three-dimensional computer planning for reverse total shoulder arthroplasty and bone grafting for severe glenoid deformity.

Computer assisted planning without patient specific instrumentation may be utilized to guide reverse total shoulder arthroplasty baseplate placement. The purpose of this study was to determine the difference between planned and achieved inclination and retroversion correction with three-dimensional preoperative computer assisted planning in reverse total shoulder arthroplasty without patient specific instrumentation with bone grafting for severe glenoid erosion. Preoperative three-dimensional computer assisted planning without patient specific instrumentation was performed on 15 patients undergoing primary reverse total shoulder arthroplasty with glenoid bone grafting for severe glenoid erosion. On preoperative and immediate postoperative computed tomography slices, two-dimensional retroversion and inclination were measured. Preoperative three-dimensional baseline retroversion and inclination and planned postoperative three-dimensional retroversion and inclination were measured. Planned and achieved version and inclination changes were compared. The planned and achieved retroversion corrections were 18° and 12°, respectively (p < 0.001). The planned and achieved inclination corrections were 11° and 11°, respectively (p = 0.803). Three-dimensional computer assisted planning without patient specific instrumentation in the setting of reverse total shoulder arthroplasty with severe glenoid erosion requiring bone grafting can accurately guide baseplate placement. All cases in which failure to correct retroversion or inclination within 10° of planning occurred in patients with severe erosion (B3 or E3 glenoids), therefore patient specific guides may be warranted in these cases to improve accuracy of implantation. Level IV, retrospective case series.

Application of Three-Dimensional Printed Vascular Modeling as a Perioperative Guide to Perforator Mapping and Pedicle Dissection during Abdominal Flap Harvest for Breast Reconstruction.

Advancements in three-dimensional (3D) printing have enabled production of patient-specific guides to aid perforator mapping and pedicle dissection during abdominal flap harvest. We present our early experience using this tool to navigate deep inferior epigastric artery (DIEA) topography and evaluate its impact on operative efficiency and clinical outcomes. Between January 2013 and December 2018, a total of 50 women underwent computed tomographic angiography (CTA)-guided perforator mapping prior to abdominal flap breast reconstruction, with (n = 9) and without (n = 41) 3D-printed vascular modeling (3DVM). Models were assessed for their accuracy in identifying perforator location and source-vessel anatomy, as determined by operative findings from 18 hemi-abdomens. The margin of error (MOE) for perforator localization using 3DVM was calculated and compared with CTA-derived measurements for the same patients. Flap harvest times, outcomes, and complications for patients who were preoperatively mapped using 3DVM versus CTA alone were analyzed. Overall, complete concordance was observed between 3DVM and operative findings with regards to perforator number, source-vessel origin, and DIEA branching pattern. By comparison, CTA interpretation of these parameters inaccurately identified branching pattern and perforator source-vessel origin in 28 and 33% of hemi-abdomens, respectively (p = 0.045 and p = 0.02). Compared with operative measurements, the average MOE for perforator localization using 3DVM was significantly lower than that obtained from CTA alone (0.81 vs. 8.71 mm, p < 0.0001). Reference of 3D-printed models, intraoperatively, was associated with a mean reduction in flap harvest time by 21 minutes (60.7 vs. 81.7 minutes, p < 0.001). Although not statistically significant, rates of perforator-level injury, microvascular insufficiency, and fat necrosis were lower among patients mapped using 3DVM. The results of this study support the accuracy of 3DVM for identifying DIEA topography and perforator location. Application of this technology may translate to enhanced operative efficiency and fewer perfusion-related complications for patients undergoing abdominal free flap breast reconstruction.

Patient Specific Guides in Total Knee Arthroplasty-Are They Accurate in Restoring Mechanical Alignment? A Prospective Clinical Series of 175 Cases

Background: Our study looked to see if patient specific guides in TKA restored mechanical alignment in patients with osteoarthritis. Materials and Methods: This prospective study measured the coronal alignment using long leg radiographs in 175 TKAs performed using patient specific cutting blocks. All patients underwent a posterior stabilizing TKA (Smith &amp; Nephew GENESIS II) by the senior surgeon (WB) using Visionaire cutting blocks (based on pre-operative MRI studies). Results: The mechanical axis of the knee joint was measured using long leg radiographs taken six weeks post-operatively. There were no adverse intraoperative events. The coronal axis was restored to within 3° of neutral in 144 of 168 knees (85.7%). Conclusion: We conclude that patient specific instrumentation is accurate in restoring mechanical alignment in patients undergoing TKA.

Corrective Four-fold Osteotomy of The Forearm Performed with 3D-Planning and Patient-Specific Guides

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