الفهرس 
Acknowledgements
Experimental Epiphyseal Plate TransfersOnly 14 pages are availabe for public view
 |  | from | 196 |  |  |
| | | from | 196 | | |
Abstract
Vascularized epiphyseal transfer is a procedure that is employed to reconstruct complex bony defects in skeletally immature subjects preserving longitudinal growth and provides a reliable articular surface for effective joint function. The most commonly used donor site is the proximal fibula although the second metatarsal and second metatarsophalangeal joint have also been reported.
Although this procedure has been carried out for over three decades, the optimal pedicle has been aa matter of debate. To the best of our knowledge, no published study exists in the literature that describes the detailed vascular anatomy of the proximal fibula, their source arteries for pedicle selection, and the relationship of motor nerves from the deep peroneal nerve to these vessels.
The purpose of this work was to provide an accurate description of the detailed vascular anatomy of the proximal fibula, and relationship of the vessels to the motor branches of the deep peroneal nerve, to facilitate the choice of the optimal pedicle for the transfer.
The purpose of the second part of the study was to review the literature on the epiphyseal transfer topic and to compare our results to those previously published.
A vascular anatomical study was conducted at the anatomy lab in Mayo Clinic, Rochester, Minnesota, USA, where 28 fresh cadaveric lower extremities were injected with latex or a mixture of latex and barium sulfate. The specimens injected with the mixture were scanned with a high-resolution CT scanner, and the images were reconstructed and studied. Then all the specimens were dissected to describe the vascular anatomy of the proximal fibula. The relationship of the motor nerves was studied in the last seven specimens.
The clinical case series was conducted by collecting all the skeletally immature patients that have undergone vascularized epiphyseal transfer both at Assiut University hospital and at Mayo Clinic. General demographic and preoperative data was collected as well as intraoperative data and data on outcome variables at follow-up. Descriptive statistics as well as logistic regression analysis was done to correlate dependent and independent variables.
A rich anastomotic vascular network was identified surrounding and supplying the fibular head in all specimens. This was formed superiorly by branches of the inferior lateral genicular artery, and inferiorly by branches of the anterior tibial artery, most important of which were the first and second recurrent epiphyseal artery. One or more deep peroneal nerve branches passed deep to the first recurrent epiphyseal artery in all specimens examined. In five specimens all the branches were superficial to the second recurrent epiphyseal artery, while two had branches deep to it.
As for the clinical case series, 23 patients were identified who underwent vascularized proximal fibular epiphyseal transfer. Eleven patients were females and 12 were males. Average age of the patients was 5 years and 11 months. The recipient site was the distal radius in 2 patients, the hip in 18 patients, the lateral condyle of the distal femur in 2 patients, and the proximal humerus in 1 patient. Ischemia time for the graft averaged 101 minutes. In 4 out of the 23 cases, motor branches to the tibialis anterior muscle were transected and sutured, and 6 out of the 23 cases had a temporary post-operative foot DROP that resolved spontaneously within 3-6 months. Average time to final follow-up was 31 months. Average total growth from the physis at final follow-up was 13.5 mm. The rate of growth from the physis was 6.6 mm/year. As a means of measuring remodeling of the transferred head of the fibula, increase in the width of the physis was calculated averaging 6.5 mm, and then the rate of increase in width was reported which averaged 3.1 mm/year. Multiple logistic regression analysis for the rate of growth of the physis was done. The result of this model showed that only age had a statistically significant relationship to the rate of growth from the physis (p-value 0.03).
One case of free vascularized second metatarsal head transfer was present in our series. The patient was a two-year-old female that suffered from late sequelae of infantile septic arthritis of the hip type 4A, with absent head and most of the neck of the left femur. The second metatarsal head was transferred to the hip. At final follow up 7 years later, length of the transferred bone was 47.8 mm with epiphyseal width of 26.3 mm, showing a yearly rate of linear growth of 3.6 mm per year.
Five patients with radial longitudinal deficiency who underwent vascularized second metatarsophalangeal joint transfer for recurrent radial club were identified. Three were males and two were females. The average age at operation was 5 years and 9 months. Three patients had type III radial longitudinal deficiency according to the Bayne and Klug Classification, and two patients had type IV radial longitudinal deficiency. Final follow-up averaged 39 months, 3 patients had an open physis, and one had a closed physis. Average rate of growth from the physis was 2.2 mm/year.
Although previous vascular anatomical studies have stressed on the importance of preserving the “artery of the neck”, authors description of this vessel varied greatly, and according to our study, this artery has inconsistency in its vessel of origin, making it not the ideal vessel to base the proximal fibular transfer on. Innocenti et al published on their successful experience with epiphyseal transfer using the reversed flow anterior tibial vessels. They based their flap on a preserved “recurrent epiphyseal artery”, which they demonstrated in preoperative angiograms of their patients. In our study, we identified two arteries that ran in a retrograde direction towards the fibular head in all specimens, and we named them the first and second recurrent epiphyseal arteries (FREA and SREA). We believe that one of these arteries is to be preserved when basing the transfer on the anterior tibial artery. The FREA had at least one major nerve branch running deep to it while the SREA had one or two branches running deep to it in only two of seven specimens, making the SREA more favorable to preserve than the FREA during epiphyseal harvest. Yang et al published on successful transfer of the proximal fibula based on the lateral inferior genicular artery, which was proved by our study due to the consistency of the vessel, although employing the ILGA may be advantageous in its easier dissection and avoidance of the extensive manipulation of the deep peroneal nerve branches, the obvious disadvantages of the short pedicle and the relatively small diameter as compared to the reversed flow ATA are to be taken into consideration. The ATA would also be a safer option when attempting to harvest a long portion of the diaphysis together with the epiphysis.
The average rate of longitudinal growth in our cohort of proximal fibular epiphyseal transfer was 6.6 mm/year, which is comparable to that described by other authors. We found out that this varied according to the child’s age at surgery, being most after 10 years of age, followed by below 5 years, and the least was between 5 and 10. We believe that this is because the older age group made use of the pubertal growth spurt, which is the major growth phase, and the younger age group made use of the toddler growth spurt.
In this cohort, a considerably large number of transfers were done to reconstruct the head and neck of the femur. Of the 16 successful patients, 13 (81%) had satisfactory results, and 3 (19%) had unsatisfactory results. we believe that this presents a very promising treatment for a population of patients without optimum management, especially those with types III and IV severe sequelae of infantile septic arthritis of the hip according to Choi classification.
We have also demonstrated the successful use of the second metatarsophalangeal joint to reconstruct the distal radius in children with recurrence of the deformity following centralization procedures, which is termed the “Vilkki procedure”. This procedure is a unique management of recurrence following centralization, providing a good functional and cosmetic wrist position with retained range of motion and growth potential.