Intramedullary Nailing Operations Research Articles

System integration of a fluoroscopic image calibration using robot assisted surgical guidance for distal locking process in closed intramedullary nailing of femur

<span>Distal locking procedure is one of the most complex tasks in close intramedullary nailing operation which requires fluoroscopic image to interpret 2-D distal locking position on image related to 3-D distal locking position on the patient site. Hence the surgeon has to perform the distal locking process by using multiple fluoroscopic images which causes a lot of x-ray exposure to the patient and surgeon and is a time consuming task. This paper presents the system integration of a fluoroscopic image calibration using robot assisted surgical guidance. The system integration consists of three parts; distal locking recovery, fluoroscopic calibration and tracking, and robot assisted surgical guidance. The distal locking-hole recovery algorithm is based on characteristic information of the major and minor axes of distal locking hole. The fluoroscopic calibration and tracking is modeled as pin-hole projection model to estimate a projection equation based on optical tracking system. The robot-assisted surgical guidance is developed to overlay a trajectory path using a laser beam for reducing the problem of hand – eye coordination on most surgical navigation system. We integrate each part to complete a surgical navigation system for distal locking process. The experiment of system integration is conducted to validate the accuracy of distal locking axis position and orientation. The results of the system integration shows a mean angular error of 1.10 and mean Euclidean distance in X-Y plane error of 3.65 mm.</span>

Pre-planning of intramedullary nailing procedures: A methodology for predicting the position of the distal hole

Inserting the distal locking screws is a challenging step of the intramedullary nailing procedures due to the nail deformation that makes the proximally mounted targeting systems ineffective. A pre-planning methodology is proposed, based on an analytical model of the nail–bone construct, to predict the nail deformation during surgery using orthogonal preoperative radiographs. Each of the femoral shaft and the nail was modeled as a curved tubular Euler–Bernoulli beam. The unknown positions and forces of the nail–bone interaction were found using a systematic trial and error approach, which minimized the total strain energy of the system while satisfying the force and geometrical constraints. The predictions of the model for the nail deformation were compared with the experimental results of five cadaver specimens in 15 test conditions. Relatively large displacements (up to 13 mm) were found for the distal hole in sagittal plane only. The model predictions were in close agreement with the experimental results, with a root mean square error of 1.2 mm. It was concluded that the proposed pre-planning methodology is promising for practical clinical use in intramedullary nailing operations, in order to provide the compensatory information that is required for tuning of proximally mounted targeting systems.

PF8 Expandable intramedullary nailing: a new method in the treatment of femoral periprosthetic fractures

Introduction: High doses of ionizing radiation are used during surgeries such as interlocking intra-medullary nailing and minimally invasive plate osteosynthesis. So, excessive use of fluoroscopy is seen to be a feared procedure among orthopedic surgeons. DAP (Dose area product) values which shows the total radiation dose with the aid of preinstalled DAPmeters, can bemonitored on the recent fluoroscopic units in mGy·cm2 or mGy·m2. This value is a more reliable indicator than the fluoroscopy time. The aim of the study is to investigate the total fluoroscopic DAP values in interlocking intramedullary nailing operations and comparing the total values with other radiologic procedures. Materials and Methods: Between 2010 and 2012, nine patients underwent femoral locking intramedullary nailing operation in our institute. Total DAP values, fluoroscopy time and number of images were retrieved from the fluoroscopic unit’s HDD. We have also recorded the DAP values of postoperative direct roentgenograms which were taken with portable digital x-ray machine which has on-board DAP meter. While the mean operation time was 3.2 hours (2–4.2 hours), total fluoroscopy use was 1.6 minutes (0.8–3.1 minutes). Results: Total mean DAP value was resulted in 1720mGy·cm2 and total number of fluoroscopic images were 44 (16–82). The mean DAP for postoperative AP and lateral direct femur radiographs were 1790mGy·cm2 and 2100mGy·cm2 respectively. We have found the total fluoroscopic unit DAP values comparable with even AP or lateral direct radiograms. Conclusion: DAP value is more practical than the fluoroscopy time in monitoring the total radiation dose used in the orthopedic procedures. If properly adjusted preoperatively, fluoroscopic units are more reliable and safe than the direct radiographies. We recommend routineuse of fluoroscopy insteadof direct radiographies intraoperatively.

PF7 Monitoring the radiation dose delivered by the fluoroscopic units with DAP (dose area product) values in locking intra-medullary nailing operations

PF7 Monitoring the radiation dose delivered by the fluoroscopic units with DAP (dose area product) values in locking intra-medullary nailing operations

A biplanar robot navigation system for the distal locking of intramedullary nails

Distal locking is the key procedure of the intramedullary nailing operation. It is difficult to precisely locate the locking path, and intraoperative radiation exposure is also a serious problem. The advantages and disadvantages of different approaches applied in this operation are summarized. A biplanar robot navigation system for the distal locking of intramedullary nails is presented. The novel mechanical structure and the surgical process are introduced. Then the positioning accuracy of the robot is experimented and validated. The positioning precision of the biplanar robot is tested, and the average error is 0.24 mm. The tibia sawbone is used for distal locking to test the accuracy of the robot navigation system. The maximal deviation between the drilling centre and the nail hole centre is 0.44 mm. The biplanar robot has the advantages of high positioning accuracy, operational stability and safety. It can be used not only for the distal locking of intramedullary nails but also for other orthopaedic surgeries that demand precise positioning.

Reducing radiation exposure in intra-medullary nailing procedures: Intra-medullary endo-transilluminating (iMET)

The purpose of the study was to reduce the level of radiation exposure during intra-medullary nailing procedures. A visible light source was inserted into the medullary bone cavity in order to detect the distal interlocking screw holes. The light penetrates out of the bone surface, revealing the position of the screw hole, and this allows the subsequent drilling and placing of the interlocking screw to be free of fluoroscopy. Among the 19 consecutive tibia-fracture patients recruited for this study, no repetition of the drilling procedure or insertion of a transverse interlocking screw was needed. The average time to finish the insertion of one distal interlocking screw was 4.1 ± 1.8 min. It was extrapolated that 13–41% of previous radiation exposure levels could be saved. The non-fluoroscopic approach thus decreases the health hazards that the patients are experiencing as well as those of the surgical team who need to perform such intra-medullary nailing operations on a routine basis.

Radiation exposure to patients in lower limb trauma surgery

Fluoroscopy equipments have enabled us to perform operations that otherwise would be impossible but only at the expense of exposing the patients and theatre staff to radiation. The aim of this study was to determine the average radiation exposure to the patients in dynamic hip screw (DHS) fixation, cannulated hip screw (CHS) fixation, intra-medullary nailing (IMN) of femur and tibia operations. The records of all patients undergoing the above operations between May 2000 and August 2003 were retrospectively reviewed. A total of 670 patients were included. 389 had DHS, 85 had CHS, 125 had IMN of femur and 71 had IMN of tibia operations. The average radiation time was 0.7, 1.1, 2.5 and 2.1 min and the average radiation dose (in dose area product-DAP) was 196, 356, 548 and 125 cGy cm2 for DHS, CHS, IMN of femur and IMN of tibia, respectively. Compared to the registrars, radiation time and dose were higher with the consultants in DHS fixation (P = 0.02, 0.02). The radiation dose was higher with the senior house officers compared to the registrars in CHS fixation (P = 0.03). There were no significant differences between the consultants and the registrars in IM nailing operations. The study concludes that radiation exposure to the patients in DHS and CHS operations depends on the experience of the surgeon but not in IMN operations. The IMN of femur involved more than four times higher radiation than IMN of tibia and the CHS fixation involved double the radiation than the DHS fixation. The radiation time was poor comparative metric to estimate radiation dose.