Journal of Limb Lengthening & Reconstruction

ORIGINAL ARTICLE
Year
: 2020  |  Volume : 6  |  Issue : 2  |  Page : 142--146

Infected regenerate in ilizarov surgery


Barakat Sayed El-Alfy1, Mohamed Fahmy Abdelaziz2, Abdallah Ibrahim Elazanki1,  
1 Department of Orthopedic Surgery, Faculty of Medicine, Mansoura University, Mansoura, Egypt
2 Department of Orthopedic Surgery, Talkha Central Hospital, Talkha, Egypt

Correspondence Address:
Prof. Barakat Sayed El-Alfy
Department of Orthopedic Surgery, Faculty of Medicine, Mansoura University, Elgomhorya Street, Mansoura, P.O. 35516
Egypt

Abstract

Background: The regenerate is the newborn of the distraction process, and it passes by many changes during its growth and maturation. Many complications can take place at the regenerate site. The aim of this study is to highlight infection as a possible complication that may affect the regenerate during bone lengthening. Patients and Methods: In this study, we present three cases who were complicated by infection of the regenerate. The diagnosis and management were described in details. Results: The predisposing factors for this complication may be patient-related or technically related factors. The isolated organisms were Escherichia coli, Staphylococcus epidermidis, and Staphylococcus aureus. Infection was controlled in all cases. The desired length was achieved in two cases, and one case was left with residual shortening of 2 cm. Conclusion: Infection of the regenerate is a rare but serious complication. A high index of suspicion is required for its diagnosis, and few options are available for its management.



How to cite this article:
El-Alfy BS, Abdelaziz MF, Elazanki AI. Infected regenerate in ilizarov surgery.J Limb Lengthen Reconstr 2020;6:142-146


How to cite this URL:
El-Alfy BS, Abdelaziz MF, Elazanki AI. Infected regenerate in ilizarov surgery. J Limb Lengthen Reconstr [serial online] 2020 [cited 2021 Mar 6 ];6:142-146
Available from: https://www.jlimblengthrecon.org/text.asp?2020/6/2/142/306107


Full Text



 Introduction



Distraction osteogenesis is the mechanical induction of new bone formation between two bony surfaces when they are gradually pulled apart. The regenerate is the newborn of the distraction process, and it passes through many changes during its growth and maturation. Many complications can take place at the regenerate site, which include premature consolidation, delayed consolidation, and refracture after frame removal.[1],[2],[3],[4]

Theoretically, the regenerate should be resistant to infection due to its huge blood supply. In an experimental study, Aronson[5] found that there is a massive increase in the local and distant blood flow to the lengthened limb. It reaches a higher peak of about ten times the control group 2 weeks after the operation; then, it decreases to four to five times for the remainder of the distraction period. During the consolidation period, the increased blood flow persisted at a level of two to three times the control group. Ilizarov[6] hypothesized that this massive increase in blood flow may wash out infection from the relatively hypovascular bone. He used this concept to heal osteomyelitis, claiming that the infection is burnt in the fire of regeneration.

The aim of this study is to highlight infection as a possible complication that may affect the regenerate during bone lengthening.

 Patients and Methods



Between May 2011 and November 2018, three cases with infected regenerate were identified among a total of 1400 cases who were managed by Ilizarov methods in our institution during this period. All patients gave their informed consent prior to surgery and the study was approved by the institutional research board.

The first case

This is a 23-year-old male patient with an open segmental fracture of his left tibia due to a road traffic accident. He was managed by intramedullary nail, but he was complicated by severe infection and sequestration of the intercalary segment. He underwent radical debridement of the infected bone and soft tissues. The Ilizarov frame was applied in the same session of debridement, and bone transport started from a proximal corticotomy. In the postoperative period, the patient continued to complain of pain at the corticotomy site. The scar of the corticotomy incision was inflamed, and it responded partially to the systemic antibiotics. The limb was swollen, and the regenerate was severely hypotrophic on radiographic examination [Figure 1]a. About 2 months after distraction, a sinus opened over the area of the regenerate and started to discharge pus. Gradual compression of the regenerate was done by the frame to squeeze the infection out, but the infection was severe and did not respond to this step. Drainage of the area of the regenerate was done to control infection. Under spinal anesthesia, the area of the regenerate was opened longitudinally and the infection was drained. The drained material was combination of pus and whitish jelly-like material. Culture and sensitivity were done, and an antibiotic was given accordingly. The infection subsided, and distraction was restarted in a slower rate than before. The regenerate was formed, but it remained hypotrophic and its consolidation was delayed. Platelet-rich plasma (PRP) was injected in the area of the week regenerate twice with an interval of 6 weeks to stimulate its consolidation.[7] This led to progressive improvement of the week regenerate until it became fully consolidated [Figure 1]b, [Figure 1]c. Shortening of 2 cm was accepted in this patient. The distraction gap was about 9 cm in length, and the external fixation time was 14 months. The external fixator index in this patient was 1.6 months/cm.{Figure 1}

The second case

This is a 36-year-old male patient, heavy smoker, with nonunited supracondylar fracture femur fixed by a long intramedullary nail bypassing the knee joint. The limb was shorter than the other side by about 5 cm [Figure 2]a.{Figure 2}

Autogenous bone graft was done at the nonunion site in the supracondylar region, and Ilizarov frame was applied to do lengthening over the preexisting nail to restore the limb length. As the knee joint was already fused by the long intramedullary nail, we preferred to do lengthening from the proximal tibia rather than the proximal femur to restore the limb length. After finishing of distraction, the area of the regenerate became hot, swollen, and tender. The patient was toxic, and his temperature was elevated (39°). The regenerate was severely hypotrophic on radiographic examination [Figure 2]b. Aspiration of the regenerate revealed pus, and it was sent for culture and sensitivity. Intravenous fluid and broad-spectrum antibiotics were given until the result of culture and sensitivity becomes available. The isolated organism was staph epidermidis, and an antibiotic was given according to the culture and sensitivity for 2 weeks. The swelling and warmth partially improved, but the collection recurred again after cessation of the antibiotic. The area of distraction was aspirated again, and 2 g of vancomycin was injected locally in the area of the regenerate. This was repeated after 2 days. The infection was controlled, and the regenerate improved on serial radiographs [Figure 2]c and [Figure 2]d. The gained length in this patient was 5 cm. The external fixation time was 7 months, and the external fixation index was 1.4 months/cm.

The third case

This is a 42-year-old male patient, diabetic on insulin. He was involved in a road traffic accident and sustained fracture of the distal third of the tibia and fibula. He underwent internal fixation by plate and screws, but he was complicated by infection and nonunion. Radical debridement and Ilizarov bone transport from a proximal tibial corticotomy were done in the same session. After reaching the docking site, the area of the regenerate became hot and tender. It was weak on radiographic examination. A small sinus opened in the skin over the regenerate and discharged pus. Culture and sensitivity were done, and the isolated organism was staph aureus. It was found to be sensitive to some antibiotics including vancomycin. One gram of vancomycin was injected locally in the area of the regenerate every other day for 10 days. The local signs of infection disappeared, and the sinus closed by the 4th injection. The regenerate improved on the follow-up radiographs, and the frame was removed [Figure 3]. The distraction gap in this patient was 6 cm, and the external fixation index was 1.7 months/cm.{Figure 3}

 Results



The isolated organisms were Escherichia coli in one case, Staphylococcus epidermidis in the second case, and Staphylococcus aureus in the third case. Infection was controlled in the three cases without recurrence during or after the course of treatment. Delayed consolidation was observed in the three cases. One of them required PRP injection to enhance its consolidation. The external fixation time was prolonged, and the external fixation index was high (1.6, 1.4, and 1.7 months/cm, respectively). The desired length was achieved in two cases, and one case was left with residual shortening of 2 cm. According to the Paly[8] evaluation system, the bone results were excellent in two cases and good in one case, while the functional results were excellent in one and good in two cases.

 Discussion



Infection of the regenerate is a rare but serious complication. There is a rarity of reports about this complication among the English literature. Eralp et al.[9] reviewed the problems, obstacles, and sequelae encountered during femoral lengthening in 111 patients. The complications related to the regenerate were premature consolidation in 4% delayed consolidation in 8% and plastic deformation of the regenerate in 4% of the patients. Infection of the regenerate was not reported in this study. In the meta-analysis done by Yin et al.[10] about Ilizarov methods in the treatment of infected nonunion of the tibia and femur, 24 studies including 590 patients were analyzed. Pin-tract infection was the most common complication; its rate ranged from 10% to 100% among the included studies. Other complications included knee stiffness, refracture, reactivation of infection, limb edema, amputation, and peroneal nerve palsy. Again, infection of the regenerate was not reported as a complication in these studies. In his article about the complications of limb lengthening by Ilizarov method, Paley[4] stated that the complications that may take place in the lengthening area are premature consolidation, delayed consolidation, axial deviation, and refracture after frame removal. He did not mention the infection of the regenerate as a possible complication.

Only El-Sayed et al.[11] reported on four cases of regenerate infection in an article about the complications of the regenerate during lengthening. These cases were treated by compression of the regenerate till the end to squeeze the pus out, and the compression was kept for 1 week, then distraction was restarted for 2 weeks, then compression was done again and kept for 1 week more, and then distraction was regained in the usual manner. This compression distraction maneuver was done with the frame and without debridement. The infection was completely eradicated, and the regenerate developed in a normal way in three of them. In the fourth case, the regenerate failed to develop and he was treated by resection of the regenerate and another corticotomy was done in a healthy site.

During our experience with Ilizarov methods, we came across three cases complicated by infection of the regenerate.

Intramedullary fixation is a possible risk factor for this complication. Two of our cases had intramedullary fixation. One of them had an infected intramedullary nail. Although the nail was removed during the definitive surgery, infection of the regenerate had occurred. This may be due to contamination of the medulla from the previous infection. In the second case, lengthening over nail was done. The isolated organism in that case was staph epidermidis. Probably, it spread along the nail from a nearby pin-tract infection.

The other risk factors may be patient related such as diabetes mellitus or smoking and technically related factors such as contamination of the medulla, contamination of the corticotomy site, and presence of an infected pin near the corticotomy site. Doing the corticotomy in the same session of debridement may lead to contamination of the osteotomy site and infection of the regenerate.

Diagnosis may be straight forward through the pain, swelling, redness, hotness, tenderness, and discharge from the area of the regenerate. Hypotrophic regenerate on radiographic examination was a constant finding in our cases and in the cases reported by El-Sayed et al.[11] In some cases, the diagnosis may be quite difficult and it may be misdiagnosed as deep venous thrombosis (DVT) due to the associated limb swelling and edema. A high index of suspicion is required for diagnosis in such cases. The triad of limb swelling, week regenerate, and tenderness over the area of the regenerate should raise the suspicion. Doppler ultrasound could be done to exclude DVT. Aspiration of pus from the area of the regenerate will confirm the diagnosis. The causative organism may be Streptococcus pyogenes, S. aureus, or Pseudomonas infection.[11] In the present study, the isolated organisms were E coli, S. epidermidis, and S. aureus. Laboratory investigations in the form of white blood cell count, erythrocyte sedimentation rate, and C-reactive protein are elevated, but the condition may be confusing, especially if the patient is being treated for infected nonunion or osteomyelitis. It will be difficult to attribute their elevation to the previous infection or the recent one at the corticotomy site, but persistent elevation may be an indicator of recent infection.

The following precautions could help to avoid infection of the regenerate:

Through debridement of the medulla in case of infection due to intramedullary nailingAvoid contamination of the corticotomy site during surgeryIn case of heavy infection, it would be wise to delay the corticotomy to another sessionThe pins and wires must be inserted at a suitable distance from the planned corticotomy siteAvoid pin-tract infection by following the proper technique for pin placement and proper car of the pins by daily dressing.[3]

Pin-tract infection is the most common complication after external fixators. In most of the cases, the infection is mild and responds to simple measures, but in some cases, it may be so severe that it could threaten the limb or patient life.[4],[8],[10],[12] Jauregui et al.[13] reported on eight cases with life and limb-threatening infection after external fixation. Four of them were due to toxic shock syndrome and four due to necrotizing fasciitis. Early diagnosis and aggressive treatment were required to save the patients' life. They further modified the classifications of pin-tract infection to accommodate these severe infections. Infection of the regenerate was associated with systemic manifestations and it was limb threatening in our cases. It fits to Class 6 of the modified Dahl et al.[14] classification.

Treatment is achieved by systemic antibiotics according to the results of culture and sensitivity. Together with the systemic antibiotics, one or more of the following options could be used.

Compression distraction

Compression will squeeze the pus out, and distraction will stimulate bone formation again. This can be repeated many times to control the infection.[11] This approach was not successful in our hands, and we adopted another protocol for management.

Debridement of the infected regenerate

Drainage and debridement of the infected regenerate are indicated if the infection is severe and did not respond to compression distraction. It is done under anesthesia through a longitudinal incision. All the infected and devitalized tissues are excised. It is an effective method, but it may end up with weak regenerate that requires biological stimulation.

Intralesional injection of antibiotics

Being soft and highly vascular, the area of regenerate could be injected with the antibiotic to achieve the highest concentration at the site of infection. Vancomycin was used for this purpose as it is known by its local effect. Vancomycin powder was proved by many authors to decrease surgical site infection after spine surgery.[15],[16],[17] Heller et al.[16] stated that direct application of 0.5–2 g of vancomycin powder to the wound just before closure decreases staphylococcal infections after posterior spinal fusion. Local injection of dissolved vancomycin was effective in treatment of two of our cases who were complicated by infection of the regenerate. Further studies may be required to adjust the dose and duration of this treatment modality.

The limitation of this study is the small number of cases and the rarity of this complication. Hence, we cannot compare our results to other studies.

 Conclusion



Infection of the regenerate is a rare but serious complication that may lead to failure of the distraction process. Intramedullary fixation and contamination of the medulla are possible risk factors. Treatment is done by systemic antibiotics together with debridement or local injection of antibiotics.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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