Percutaneous Antibiotic Delivery Technique into the Calcaneus
Percutaneous Antibiotic Delivery Technique into the Cuboid
Percutaneous Antibiotic Delivery Technique
The PAD-T was developed in 2009 by Dr. Karr and used extensively as a safe, extremely effective means utilizing a bone void filler consisting of calcium sulfate and phosphate to deliver antibiotics into an area of bone infection. The PAD-T involves a small percutaneous skin incision followed by a small bone cortex incision into the infected bone. Irrigation and spongiosum bone cultures can be done through the bone cortex incision. Through this small bone cortex incision, while in the liquid state, a bone void filler mixed with usually tobramycin and vancomycin is delivered under fluoroscopy into the area of bone infection. The procedure is done in the operating room and the patient can generally weight bear afterwards. This technique avoids a more invasive bone surgery, thus this minimizes time away from work, and generally requires no change in weight bearing status. The bone void filler used is Cerament but any bone void filler can be utilized.
TECHNIQUE
Thorough pre-operative imaging review and familiarization of the three-dimensional anatomy of the area of osteomyelitis is paramount to successful percutaneous antibiotic delivery. The set up for this procedure is fairly simple and is illustrated in figure 1. Preferably the patient should be off antibiotics for one week before this procedure in an attempt to obtain meaningful bone cultures. A tourniquet should be utilized to minimize medullary bleeding.
On the back table 1.2 grams of tobramycin and 1 gram of vancomycin is placed separately in small cups. A simple percutaneous skin incision is completed superficial to the area of osteomyelitis. Under intra-operative fluoroscopy a bone cortex incision in the near bone cortex is then completed with a smooth steinman 9/64-inch pin into the area of osteomyelitis. The steinman pin is then advanced to the far bone cortex without far bone cortex violation. Usually a single plane pass of the steinman is sufficient. More than one pass of the steinman pin is usually not necessary as long as a sufficient volume of the bone void filler is delivered to the area of osteomyelitis. Multiple passes of the steinman pin in long bones can unnecessary increase the risk of stress risers and should be avoided. At this point bone biopsies for bacteria can be completed with a curved curette and irrigation can be completed. The bone void filler is mixed per protocol and then added too the two antibiotics that were already placed into a basin and mixed with the spatula. The back stopper is removed from a twenty cc syringe and this completed mixture is placed into the syringe and the back stopper replaced. This loaded syringe is then connected to the number three kyphon bone biopsy device. Under intra-operative fluoroscopy the kyphon device is then advanced through the guide hole at the near bone cortex incision into the spongiosum bone and advanced to the far cortex. The kyphon device is then slowly withdrawn under intra-operative fluoroscopy while depressing the plunger delivering the bone void filler and selected antibiotics. There should be a nice filling effect seen under intra-operative fluoroscopy as the bone void filler and selected antibiotics fill the damaged spongiosum bone. There is excellent radio opacity of the selected bone void filler. In the situation where a two plane delivery is planned, after the first pass of the bone void filler and selected antibiotics the percutaneous soft tissue incision should be closed by standard technique before the second pass is initiated. This is done so there is no leaking from the first percutaneous soft tissue incision when the second pass is delivering this combination into the bone.
DISCUSSION
The effectiveness and success of the PAD-T is based in the interaction of the bone void filler carrier vehicle with the selected antibiotic(s) and the infected bone. The process of osteomyelitis is one of bone destruction, osseous vascular destruction and congestion, and biofilm generation. Once the process of osteomyelitis initiates, bone is destroyed leaving a path of least resistance throughout the effected bone. In chronic osteomyelitis the devitalized and compromised bone harbors biofilm containing pathogens that are resilient and serve as nidus for continued infection. Even in the acute osteomyelitis patient that is managed with bone debridement and irrigation removing the free-swimming pathogens the sessile, adherent pathogens with the biofilm remain. The successful treatment of this biofilm is further diminished by the micro-vascular destruction and congestion within the infected bone, thus interfering with the body’s ability to deliver antibiotics to the area of bone infection. The PAD-T bone void filler carrier vehicle is utilized in the liquid phase before hardening occurs. This allows the bone void filler to move along the path of least resistance created by the bone infection. Once successfully delivered, the bone void filler is now in contact with all bone surfaces and biofilm within the area of osteomyelitis. The selected antibiotic(s) within the bone void filler are now in contact with all infected bone surfaces and biofilm independent of the locally compromised circulation. An in vitro study of zones of inhibition created by Cerament as the bone void filler mixed with either a single or combination of different antibiotics vs. methicillin resistant staphylococcus aureus or pseudomonas aerginosum was done in comparison to the clinical laboratory standards institute’s (CLSI) criteria for minimal inhibitory concentration (MIC). The results demonstrated consistent zones of inhibition for all antibiotics tested well beyond the MIC for susceptibility for all antibiotics tested.
This new PAD-T presented for the adjunctive management of osteomyelitis allows easy, direct placement of either concentrated antibiotic or antifungal medication into the area of osteomyelitis. There is no restriction to either antibiotic or antifungal medication to be added to the bone void filler. Because of the simple skin and bone cortex incision there is no required change in weight bearing in the post-operative period. The extent or even the presence of osteomyelitis can sometimes be evaluated by the amount of resistance encountered when delivering the bone void filler with antibiotic into the bone. This can have value in evaluating a patient with known osteomyelitis in one bone with suspected osteomyelitis in other bones. When viewing the delivering the bone void filler ron intra-operative fluoroscopy the amount of bone filling will increase as the extent of osteomyelitis increases within the bone. Thus, if there is significant resistance to the delivery of the bone void filler in a bone there is an increased likelihood osteomyelitis is not present.
TECHNIQUE
Thorough pre-operative imaging review and familiarization of the three-dimensional anatomy of the area of osteomyelitis is paramount to successful percutaneous antibiotic delivery. The set up for this procedure is fairly simple and is illustrated in figure 1. Preferably the patient should be off antibiotics for one week before this procedure in an attempt to obtain meaningful bone cultures. A tourniquet should be utilized to minimize medullary bleeding.
On the back table 1.2 grams of tobramycin and 1 gram of vancomycin is placed separately in small cups. A simple percutaneous skin incision is completed superficial to the area of osteomyelitis. Under intra-operative fluoroscopy a bone cortex incision in the near bone cortex is then completed with a smooth steinman 9/64-inch pin into the area of osteomyelitis. The steinman pin is then advanced to the far bone cortex without far bone cortex violation. Usually a single plane pass of the steinman is sufficient. More than one pass of the steinman pin is usually not necessary as long as a sufficient volume of the bone void filler is delivered to the area of osteomyelitis. Multiple passes of the steinman pin in long bones can unnecessary increase the risk of stress risers and should be avoided. At this point bone biopsies for bacteria can be completed with a curved curette and irrigation can be completed. The bone void filler is mixed per protocol and then added too the two antibiotics that were already placed into a basin and mixed with the spatula. The back stopper is removed from a twenty cc syringe and this completed mixture is placed into the syringe and the back stopper replaced. This loaded syringe is then connected to the number three kyphon bone biopsy device. Under intra-operative fluoroscopy the kyphon device is then advanced through the guide hole at the near bone cortex incision into the spongiosum bone and advanced to the far cortex. The kyphon device is then slowly withdrawn under intra-operative fluoroscopy while depressing the plunger delivering the bone void filler and selected antibiotics. There should be a nice filling effect seen under intra-operative fluoroscopy as the bone void filler and selected antibiotics fill the damaged spongiosum bone. There is excellent radio opacity of the selected bone void filler. In the situation where a two plane delivery is planned, after the first pass of the bone void filler and selected antibiotics the percutaneous soft tissue incision should be closed by standard technique before the second pass is initiated. This is done so there is no leaking from the first percutaneous soft tissue incision when the second pass is delivering this combination into the bone.
DISCUSSION
The effectiveness and success of the PAD-T is based in the interaction of the bone void filler carrier vehicle with the selected antibiotic(s) and the infected bone. The process of osteomyelitis is one of bone destruction, osseous vascular destruction and congestion, and biofilm generation. Once the process of osteomyelitis initiates, bone is destroyed leaving a path of least resistance throughout the effected bone. In chronic osteomyelitis the devitalized and compromised bone harbors biofilm containing pathogens that are resilient and serve as nidus for continued infection. Even in the acute osteomyelitis patient that is managed with bone debridement and irrigation removing the free-swimming pathogens the sessile, adherent pathogens with the biofilm remain. The successful treatment of this biofilm is further diminished by the micro-vascular destruction and congestion within the infected bone, thus interfering with the body’s ability to deliver antibiotics to the area of bone infection. The PAD-T bone void filler carrier vehicle is utilized in the liquid phase before hardening occurs. This allows the bone void filler to move along the path of least resistance created by the bone infection. Once successfully delivered, the bone void filler is now in contact with all bone surfaces and biofilm within the area of osteomyelitis. The selected antibiotic(s) within the bone void filler are now in contact with all infected bone surfaces and biofilm independent of the locally compromised circulation. An in vitro study of zones of inhibition created by Cerament as the bone void filler mixed with either a single or combination of different antibiotics vs. methicillin resistant staphylococcus aureus or pseudomonas aerginosum was done in comparison to the clinical laboratory standards institute’s (CLSI) criteria for minimal inhibitory concentration (MIC). The results demonstrated consistent zones of inhibition for all antibiotics tested well beyond the MIC for susceptibility for all antibiotics tested.
This new PAD-T presented for the adjunctive management of osteomyelitis allows easy, direct placement of either concentrated antibiotic or antifungal medication into the area of osteomyelitis. There is no restriction to either antibiotic or antifungal medication to be added to the bone void filler. Because of the simple skin and bone cortex incision there is no required change in weight bearing in the post-operative period. The extent or even the presence of osteomyelitis can sometimes be evaluated by the amount of resistance encountered when delivering the bone void filler with antibiotic into the bone. This can have value in evaluating a patient with known osteomyelitis in one bone with suspected osteomyelitis in other bones. When viewing the delivering the bone void filler ron intra-operative fluoroscopy the amount of bone filling will increase as the extent of osteomyelitis increases within the bone. Thus, if there is significant resistance to the delivery of the bone void filler in a bone there is an increased likelihood osteomyelitis is not present.
