Patient-specific Drill Guides Research Articles

Clinical outcomes of 20 brachycephalic dogs with thoracolumbar spinal deformities causing neurological signs treated with spinal stabilization using 3D-printed patient-specific drill guides.

To describe the clinical outcomes for pugs and French bulldogs with congenital vertebral malformations, undergoing thoracolumbar spinal stabilization surgery using 3D-printed patient-specific drill guides. To evaluate the accuracy of pedicle screw placement in this group of dogs. Retrospective descriptive study. Twenty dogs (12 pugs and eight French bulldogs). Medical records searched between August 2018 and March 2021 for pugs and French bulldogs diagnosed with congenital vertebral abnormalities via magnetic resonance imaging (MRI) scan and computed tomography (CT) scan causing T3-L3 myelopathy signs that underwent spinal stabilization surgery using 3D-printed patient-specific drill guides followed by a postoperative CT scan. The short-term outcome was based on the neurological grade (modified Frankel score-MFS) on the day after surgery, day of discharge, and at the follow-up examination at 4 to 6 weeks after surgery. The mid-term outcome was obtained via an online questionnaire (or direct examination in one case). Twenty dogs met the inclusion criteria (19/20 grade 2 MFS, 1/20 grade 4 MFS). No complications were reported in the immediate postoperative period and optimal pedicle screw placement was obtained in 169/201 of screws. Twenty-four hours after surgery 16/20 dogs displayed an unchanged neurological grade. Short-term outcomes revealed a static (17/20) or improved (2/20) neurological grade. Ten owners participated in the online questionnaire. All patients were reported to be ambulatory; however, 7/10 dogs displayed abnormal gait. Neurological signs had remained static (6/10) or improved (3/10) in comparison with the dogs' preoperative status at a median of 883.5 days from the surgery. Dogs in this study had a favorable short-term outcome and mid-term outcome evaluation revealed a static/improved neurological status. Thoracolumbar spinal stabilization surgery using 3D-printed patient-specific drill guides showed a favorable outcome in brachycephalic breeds affected by vertebral deformities.

Accuracy of pin placement in the canine thoracolumbar spine using a free-hand probing technique versus 3D-printed patient-specific drill guides: An ex-vivo study.

To compare pin placement accuracy, intraoperative technique deviations, and duration of pin placement for pins placed by free-hand probing (FHP) or 3D-printed drill guide (3DPG) technique. Four greyhound cadavers. Computed tomography (CT) examinations from T6-sacrum were obtained for determination of optimal pin placement and 3DPG creation. Two 3.2/2.4-mm positive profile pins were inserted per vertebra, one left and one right from T7-L7 (FHP [n = 56]; 3DPG [n = 56]) by one surgeon and removed for repeat CT. Duration of pin placement and intraoperative deviations (unanticipated deviations from planned technique) were recorded. Pin tracts were graded by two blinded observers using modified Zdichavsky classification. Descriptive statistics were used. A total of 54/56 pins placed with 3DPGs were assigned grade I (optimal placement) compared with 49/56 pins using the FHP technique. A total of 2/56 pins placed with 3DPGs and 3/56 pins using the FHP technique were assigned grade IIa (partial medial violation). A total of 4/56 pins placed using the FHP technique were assigned grade IIIa (partial lateral violation). No pins were assigned grade IIb (full medial violation). Intraoperative technique deviations occurred with 6/56 pins placed using the FHP technique and no pins with 3DPGs. Overall, pins were placed faster (mean ± SD 2.6 [1.3] vs. 4.5 [1.8] min) with 3DPGs. Both techniques were accurate for placement of spinal fixation pins. The 3DPG technique may decrease intraoperative deviations and duration of pin placement. Both techniques allow accurate pin placement in the canine thoracolumbar spine. The FHP technique requires specific training and has learning curve, whereas 3DPG technique requires specific software and 3D printers.

Thoracolumbar Spinal Stabilization with Three Dimensional-Printed Drill Guides and Pre-Contoured Polyaxial Bone Plates.

The aim of this study was to report new preoperative and intraoperative techniques performed for canine thoracic or lumbar spine kyphosis stabilization using three-dimensional-printed patient-specific drill guides, polyaxial titanium bone plates and drill stops, and to determine the accuracy of screw placement using these techniques. Retrospective study, five client-owned dogs. Three-dimensional-printed patient-specific drill guides and drill stops allowed safe drilling and screw placement in all of the cases, with (i) 84% of the screws graded as I (ideal placement) and 16% as IIa, IIIa or IIIb according to the modified Zdichavsky classification (partial penetration of medial pedicle wall, partial penetration of lateral pedicle wall and full penetration of lateral pedicle wall respectively), (ii) mean mediolateral deviation of ± 4.06 degrees (standard deviation: 8.21 degrees) compared to planned trajectories and (iii) variation in screw depth of ± 2.29mm (standard deviation: 3.07mm) compared to planned depth. We believe that the techniques presented here for thoracic spinal stabilization in dogs show promise; they allowed safe placement of screws along planned trajectories and depth; they also removed the need to use polymethylmethacrylate, while the use of titanium offers the possibility to repeat magnetic resonance imaging in these cases with chronic spinal conditions.

Accuracy of a patient-specific 3D-printed drill guide for placement of bicortical screws in atlantoaxial ventral stabilization in dogs.

Atlantoaxial instability (AAI) in dogs refers to abnormal motion at the C1–C2 articulation due to congenital or developmental anomalies. Surgical treatment options for AAI include dorsal and ventral stabilization techniques. Ventral stabilization techniques commonly utilize transarticular and vertebral body screws or pins. However, accurate screw insertion into the vertebrae of C1 and C2 is difficult because of the narrow safety corridors. This study included 10 mixed dogs, 1 Pomeranian, and 1 Shih-Tzu cadaver. All dogs weighed <10 kg. Each specimen was scanned using computed tomography (CT) from the head to the 7th cervical vertebrae. This study used 12 bone models and 6 patient-specific drill guides. Bone models were made using CT images and drill guides were created through a CAD (computer-aided design) program. A total of six cortical screws were used for each specimen. Two screws were placed at each of the C1, C2 cranial, and C2 caudal positions. Postoperative CT images of the cervical region were obtained. The degree of cortex breaching and angle and bicortical status of each screw was evaluated. The number of screws that did not penetrate the vertebral canal was higher in the guided group (33/36, 92%) than in the control group (20/36, 56%) (P = 0.003). The screw angles were more similar to the reference angle compared to the control group. The number of bicortically applied screws in the control group was 28/36 (78%) compared to 34/36 (94%) in the guided group. Differences between the preoperative plan and the length of the applied screw at the C1 and C2 caudal positions were determined by comparing the screw lengths in the guide group. The study results demonstrated that the use of a patient-specific 3D-printed drill guide for AAI ventral stabilization can improve the accuracy of the surgery. The use of rehearsal using bone models and a drilling guide may improve screw insertion accuracy.

The Feasibility of Creating Image-Based Patient-Specific Drill Guides for the Atlantoaxial Instabilities Using Open-Source CAD Software and Desktop 3D Printers

C1/2 cervical pedicle screw fixation is a well-known procedure for treating severely damaged and unstable C1/2 fractures. On the other hand, C1/C2 screw fixation is not safe and can lead to potentially disastrous consequences. The importance of personalized 3-dimensional (3D) printed navigational guides in avoiding these consequences cannot be overstated. We retrospectively reviewed the neuroimaging data of 16 patients who had undergone fixation for treatment of C1/2 diseases. We created patient-specific C1/2 models and drill guide models using open-source 3D editing software and a desktop 3D printer. The drill guides were then placed over the respective vertebrae models and fixated with 3.5-mm screws. Following fixation, the parts were scanned with a thin-slice (01mm) computed tomography scan, and the screw trajectories in the transverse and sagittal planes were measured at each level. Of the total of 62 screws, 58 were type I (93.54%), 4 were type II (6.45%), and no screws were type III. The results showed that there was no significant deviation in the screw trajectories and the accuracy of the drill guides was 93.54%. In our study, type I and type II screws were deemed acceptable, and the acceptable rates of C1/2 screw fixation were 100%. In this preclinical study, we demonstrated that it is possible to create patient-specific pedicle drill guides using open-source editing software and a commercially available desktop polylactic acid printer, resulting in high accuracy rates in pedicle screw placement in C1/2 patient models.

Accuracy of Patient-Specific Drill Guide Template for Bilateral C1-C2 Laminar Screw Placement: A Cadaveric Study

We sought to evaluate the accuracy of using patient-specific drill guides to place bilateral laminar screws in C1 and C2. Nine cervical specimens (8 males; mean age: 66.6 [56-73]) with the occiput attached (C0-C3) were used in this study. Preoperative computed tomography (CT) scans were used to create digital anatomic models for templating and guide creation. A total of 36 screws were placed with the aid of 3-dimensional printed, patient-specific guides (2 screws at C1 and C2). Postoperative CT scans were performed following screw insertion. The planned and actual trajectories were compared using preoperative and postoperative imaging based on the angular and entry point deviation. After screw placement and postoperative imaging, each specimen was dissected and performed a visual inspection for breaches. No breaches or violations were observed on postprocedural CT and visual inspection. The average variation of the entry point in the X, Y, and Z axes was 0.3 ± 0.28, 0.41 ± 0.38, and 0.29 ± 0.24, respectively. No statistically significant difference (P > 0.05) was observed between the planned and obtained entry points. There was no significant difference (P > 0.05) in the deviation analysis between the planned and obtained angles in the axial and coronal planes. The study demonstrates that patient-specific drill guides allow for accurate C1 and C2 bilateral laminar screw placement, with a low risk of cortical breach.

A calibration-free workflow for image-based mixed reality navigation of total shoulder arthroplasty

ABSTRACT Accurate pin placement to guide renaming of the glenoid surface in total shoulder arthroplasty (TSA) is a critical step to restore range of motion in the glenohumeral joint. Achieving proper pin position with free-hand is complicated due to inadequate intra-operative availability of pre-operative planning data. Mixed reality provides a new modality of surgical navigation for arthroplasty without distracting surgeon from the patient anatomy. However, achieving accurate alignment between the pre-operative plan and the intra-operative anatomy is challenging, especially if workflow-compliant solutions are desired. In this paper, we present a calibration-free mixed reality navigation workflow for glenoid pin placement in TSA that contributes to solving some open challenges. We use a visible light stereo camera on a surgical support arm combined with a transformer-based disparity estimation algorithm to accurately reconstruct the 3D anatomy despite surgical lighting. Besides, we introduce a slide-on marker calibrated by design to overcome perceptual difficulties that arise when trying to align real to virtual objects. In a user study on a semi-anthropomorphic phantom, we assess the end-to-end pin placement accuracy using both our system and a clinical reference standard solution that relies on patient-specific drill guides. Averaging over 15 drilled trajectories, our mixed reality system achieved a pin placement accuracy of ( mm, ).

2021 Canadian Spine Society Abstracts.

# Abstract 45. Determining clinically important improvement following surgery for degenerative conditions of the spine: analysis of the Canadian Spine Outcomes and Research Network (CSORN) Registry {#article-title-2} There is significant variability in clinically important improvement (CII)

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.

Accuracy of Placement of Pedicle Screws in the Lumbosacral Region of Dogs Using 3D-Printed Patient-Specific Drill Guides.

The aim of this study was to report the accuracy of pedicle screw placement using three-dimensional (3D)-printed, patient-specific drill guides in the lumbosacral region of dogs. This was a retrospective study. Thirty-two pedicle screws were placed in five dogs. Medical records were reviewed between November 2015 and November 2018 for dogs showing clinical signs associated with cauda equina syndrome. Inclusion criteria included preoperative magnetic resonance imaging, pre- and postoperative computed tomography (CT) and dorsal stabilization, with pedicle screws placed using 3D-printed, patient-specific drill guides and polymethylmethacrylate. Screw placement was evaluated for medial or lateral breaching on postoperative CT. Five dogs met the inclusion criteria. Four had degenerative lumbosacral stenosis and one had discospondylitis. All dogs had failed medical management prior to surgery. Of 32 bicortical pedicle screws placed, 30 were fully contained inside the pedicle and 2 were partially breaching the vertebral canal (less than one-third of the screw diameter). Postoperative CT revealed good alignment of L7-S1 in all planes. This technique enabled an accurate and safe placement of pedicle screws in the lumbosacral region of dogs with lumbosacral disease. Three-dimensional, printed patient-specific drill guides are a safe and effective method of placing pedicle screws in dogs with lumbosacral disease.

Three-dimensional Printed Drill Guides Versus Fluoroscopic-guided Freehand Technique for Pedicle Screw Placement: A Systematic Review and Meta-analysis of Radiographic, Operative, and Clinical Outcomes.

A systematic review and meta-analysis. The objective of this study was to compare surgical, clinical, and radiographic outcomes of 3-dimensional printed (3DP) drill guides to the fluoroscopic-guided, freehand placement of pedicle screws in the spine. 3DP is a budding technology in spine surgery and has recently been applied to patient-specific drill guides for pedicle screw placement. Several authors have reported the benefits of these drill guides, but no clear consensus exists on their utility. A comprehensive search of the literature was conducted and independent reviewers assessed eligibility for included studies. Outcomes analyzed included: total operation time, estimated blood loss, screw accuracy, pain score, Japanese Orthopedic Association score, and postoperative complications. Weighted mean differences (WMD) and weighted risk differences were calculated using a random-effects model. Six studies with a total of 205 patients were included. There were significantly lower operation times [WMD=-32.32 min, 95% confidence interval (CI)=-53.19 to -11.45] and estimated blood loss (WMD=-51.42 mL, 95% CI=-81.12 to -21.72) in procedures performed with 3DP drill guides as compared with freehand technique. The probability of "excellent" screw placement was significantly higher in 3DP guides versus freehand (weighted risk difference=-0.12, 95% CI=-0.17 to 0.07); however, no differences were observed in "poor" or "good" screw placement. There were no significant differences between groups in pain scores or Japanese Orthopedic Association scores. No difference in the rate of surgical complications was noted between the groups. Pedicle screws placed with 3DP drill guides may result in shorter operative time, less blood loss, and a greater probability of excellent screw placement as compared with those placed with freehand techniques. We conclude that 3DP guides may potentially develop into an efficient and accurate option for pedicle screw placement. However, more prospective, randomized controlled trials are needed to strengthen the confidence of these conclusions. Level III.

Accuracy of three-dimensional printed patient-specific drill guides for treatment of canine humeral intracondylar fissure.

To determine the accuracy of three-dimensional printed patient-specific drill guides (3D-PDG) as treatment of humeral intracondylar fissures (HIF) in dogs. Retrospective consecutive case series. Client-owned dogs with HIF treated with a 5-mm transcondylar screw (TCS) placed from medial to lateral with a 3D-PDG. The proposed TCS entry point and trajectory were planned using computed tomography (CT) data and computer-aided design software (CAD), and a 3D-PDG was produced. During surgery the 3D-PDG was used to drill the pilot hole from medial to lateral; the guide was then removed, the pilot hole was overdrilled, and a 5-mm TCS was placed. Postoperative CT data were imported into CAD software, and the entry points, exit points, and trajectories were compared between the planned and actual screw locations. Sixteen elbows from 11 dogs were included. Mean (SD) entry point translation was 1.3 mm (0.64), with all screws entering cranial to the proposed location. Mean maximum screw angulation was 5.2° (2.10°), with most screws directed caudodistal to the desired trajectory. Mean (SD) exit point translation was 1.8 mm (0.89) from the planned location. There was no intra-articular screw placement. Use of a 3D-PDG permitted accurate placement of a mediolateral 5-mm locking TCS within the humeral condyle. Three-dimensional printed patient-specific drill guides should be considered as accurate and consistent for placing TCS for treatment of HIF in dogs.

Accuracy of placement of pedicle screws in the thoracolumbar spine of dogs with spinal deformities with three-dimensionally printed patient-specific drill guides.

To determine the accuracy of pedicle screw placement in the thoracic spine of dogs with spinal deformities with three-dimensionally (3D) printed patient-specific drill guides. Retrospective study. Six dogs in which sixty pedicle screws were placed in the thoracolumbar spine. Medical records were searched between June 2017 and June 2018 for dogs with clinical signs associated with a thoracolumbar vertebral malformation. Inclusion criteria included MRI and computed tomography (CT) data that were used to create 3D printed patient-specific drill guides. All dogs were stabilized dorsally with guided bicortical pedicle screws and polymethylmethacrylate. Accuracy of screw placement was assessed by immediately postoperative CT according to a modified Zdichavsky classification. Five pugs and one French bulldog met the inclusion criteria. Sixty bicortical pedicle screws were placed; 96.7% were graded as I (optimal placement), and 3.3% were classified as IIa (partial penetration of the medial pedicle wall) according to a modified Zdichavsky classification. Three-dimensionally printed patient-specific drill guides allowed safe and accurate placement of pedicle screws in the thoracolumbar spine in dogs with vertebral malformation. Three-dimensionally printed patient-specific drill guides are a safe and effective method of placing pedicle screws in dogs with thoracolumbar vertebral malformations.

Three-Dimensional Planning and Patient-Specific Drill Guides for Repair of Spondylolysis/L5 Pars Defect

Incomplete ossification of the pars interarticularis will result in a pars defect, a common cause of low back pain in youth and strongly associated with participation in high-impact sports. If left untreated, it can result in spondylolisthesis, causing dynamic canal stenosis, low back pain, and radiculopathy. The treatment of pars defect was first described by Bucks in 1970, who used screws in the lamina placed through an upward and outward direction. However, because of the multiple inclusion and exclusion criteria and narrow margin of error, the Bucks pars repair technique is not commonly performed. A 28-year-old woman had with low back pain that she had been experiencing since mid-adolescence. Computed tomography revealed a bilateral L5 pars defect without spondylolisthesis. Her L5 vertebra was reconstructed virtually. The screw trajectories, a 3-dimensional (3D) model of the vertebra, and a patient-specific drill guide (PSDG) were designed and printed using positioning guide software (MySpine MC Guides [Medacta International SA, Castel San Petro, Switzerland]). A modified Bucks procedure using cannulated compression screws and the PSDG was performed. Follow-up computed tomography revealed accurate placement of the compression screws, mirroring the planned trajectory. The patient was pain free at 3 months postoperatively, and early union across the defect was visualized on the 5-month radiographic imaging study. Using 3D planning software, complex surgical procedures can be planned using the patient's anatomy and computed tomography. With the aid of 3D-printed PSDGs, screw placement in narrow corridors, such as was shown in our case, is safe, efficient, and achievable.

Accuracy Assessment of Pedicle and Lateral Mass Screw Insertion Assisted by Customized 3D-Printed Drill Guides: A Human Cadaver Study.

Accurate cervical screw insertion is of paramount importance considering the risk of damage to adjacent vital structures. Recent research in 3-dimensional (3D) technology describes the advantage of patient-specific drill guides for accurate screw positioning, but consensus about the optimal guide design and the accuracy is lacking. To find the optimal design and to evaluate the accuracy of individualized 3D-printed drill guides for lateral mass and pedicle screw placement in the cervical and upper thoracic spine. Five Thiel-embalmed human cadavers were used for individualized drill-guide planning of 86 screw trajectories in the cervical and upper thoracic spine. Using 3D bone models reconstructed from acquired computed tomography scans, the drill guides were produced for both pedicle and lateral mass screw trajectories. During the study, the initial minimalistic design was refined, resulting in the advanced guide design. Screw trajectories were drilled and the realized trajectories were compared to the planned trajectories using 3D deviation analysis. The overall entry point and 3D angular accuracy were 0.76±0.52 mm and 3.22±2.34°, respectively. Average measurements for the minimalistic guides were 1.20 mm for entry points, 5.61° for the 3D angulation, 2.38° for the 2D axial angulation, and 4.80° for the 2D sagittal angulation. For the advanced guides, the respective measurements were 0.66 mm, 2.72°, 1.26°, and 2.12°, respectively. The study ultimately resulted in an advanced guide design including caudally positioned hooks, crosslink support structure, and metal inlays. The novel advanced drill guide design yields excellent drilling accuracy.

Total knee arthroplasty. Patient-specific instruments and implants

This article describes the concept and surgical technique of patient-specific total knee arthroplasty. Patient-specific implants and instruments are designed and fabricated based on computed tomography (CT) data of the leg. The disposable patient-specific drill guides and cutting-jigs are manufactured taking into consideration the anatomical and biomechanical axes of the knee joint and mediating the efficient pre-navigation of the osseous saw-cuts, without the need for additional navigation or balancing aids. The surgical plan is made on the basis of the CT data. The implantation technique comprises the following steps: distal femoral resection, tibial resection, balancing and femur preparation, tibia preparation, optional patellar resurfacing, trialling of the test components, and implantation of the final components. By using this patient-specific implant system, which includes not only personalized, single-use instruments, but also individualized implants, the surgeon is able to provide endoprosthetic treatment that broadly restores the patient's own knee anatomy and knee kinematics. Preliminary studies have proven the concept and data on this technology are promising so far; however, like a new implant, they are usually limited. In particular, comparative long-term clinical data are still to come.

Individualized total knee arthroplasty

This article describes the rationale and the surgical technique of patient-specific uni-, bi-, or three-compartmental knee arthroplasty using the second generation (G2) of ConforMIS™ technology. The patient-individual implants and instruments are designed and fabricated based on data from a preoperative computed tomography of the lower limb. The disposable patient-specific drill guides and cutting-jigs are manufactured under consideration of the anatomical and biomechanical axes of the knee joint and mediate efficient pre-navigation of the saw-cuts on the femoral and tibial bone without the need for an additional navigation or balancing device. The surgical technique for all types of knee resurfacement comprises the steps of cartilage removal, knee balancing in extension and flexion, sparing bony cuts, final preparation of femur and tibia, trialling, cementing of components and final choice of tibial insert. The use of individualized three-dimensional image-derived resurfacing implants, as well as personalized single-use instrumentation, facilitates the surgeon to perform an almost anatomical knee resurfacement that has the potential to restore almost normal knee kinematics. The limited data on this novel technology is promising, however long-term clinical data is needed for final evaluation of this technology.

Three-Dimensional Correction of Distal Radius Intra-Articular Malunions Using Patient-Specific Drill Guides

To analyze the feasibility of combining computer-assisted 3-dimensional planning with patient-specific drill guides and to evaluate this technology's surgical outcomes for distal radius intra-articular malunions. Six symptomatic patients with intra-articular malunions of the distal radius with a stepoff of more than 2 mm were treated with an outside-in corrective osteotomy. The described cases consist of 2 malunited volar Barton fractures, 2 radial styloid fractures, 1 AO-type C1 fracture, and 1 die-punch fracture. The osteotomies were guided by 3-dimensionally generated aiming guides that allowed precise cutting and the reduction of up to 2 fragments. All 6 patients were examined clinically and radiologically after 1 year. The surgical outcomes were quantitatively analyzed by comparing the preoperative and postoperative computed tomographic data. In all 6 cases, the osteotomies were consolidated 8 weeks postoperatively. After 1 year, 4 patients were pain-free, 1 had mild pain, and 1 experienced moderate pain during heavy work. Wrist motion and grip strength were improved in all patients. The postoperative radiographs showed no articular stepoff or degenerative changes. Patient-specific aiming guides provided a reliable method to correct intra-articular malunions of the distal radius. This technique allows the surgeon to safely perform difficult intra-articular osteotomies and may help limit the need for salvage procedures such as partial or complete wrist arthrodesis. Therapeutic IV.