|Year : 2019 | Volume
| Issue : 2 | Page : 100-104
Use of cable bone transport as a method of soft tissue preservation
Fadi Foad Aboud, Pavel Alexander Nudelman, Haim Shtarker
Department of Orthopedic Surgery, Galilee Medical Center, Nahariya, Israel
|Date of Submission||25-Aug-2019|
|Date of Decision||22-Sep-2019|
|Date of Acceptance||12-Nov-2019|
|Date of Web Publication||31-Dec-2019|
Dr. Fadi Foad Aboud
Department of Orthopedics A, Galillee Medical Center, 89 Nahariya-Cabri, Nahariya
Source of Support: None, Conflict of Interest: None
Context: Ilizarov method of bone transport is a well-recognized method in treating bone loss; however, soft tissue complications and potential flap compromise associated with the transport process are a major drawback. Aim: We propose the use of a central transport system of cables and pulleys, as introduced by Weber in 1998 to help preserve soft tissue cover, retain flap integrity, and decrease patient discomfort. Design: This was a retrospective study. Patients and Methods: Consecutive series of patients treated for severe bone loss and fragile soft tissue cover, between 2013 and 2018, according to the Weber method of bone transport, were included in the study. In total, six cases were identified. Inclusion criteria were any patient who underwent bone transport using the Weber method due to bone loss caused by trauma or infection. Exclusion criteria were any patient who did not complete the bone distraction process or had a follow-up of <1 month after bone transport apparatus installation. Results: Five out of six patients completed the bone transport process; one case was excluded from the results since the patient was lost to follow-up before bone distraction was begun. The average follow-up was 13.2 months; no patient had soft tissue complications, the transport process was painless, and the flap integrity was maintained. Bone regenerate was good in all except one case since the patient was lost to follow-up a month after transport was initiated. Conclusion: The Weber method is a reliable technique generating good-quality bone, while maintaining the integrity of the soft tissue envelope, minimizing soft tissue complications associated with the classical method of bone transport. The Weber technique is especially valuable when bone transport is performed in a flap covered area, where the excursion of half pins and K-wires can compromise flap survival.
Keywords: Bone loss, bone transport, distraction osteogenesis, flap preservation, soft tissue preservation
|How to cite this article:|
Aboud FF, Nudelman PA, Shtarker H. Use of cable bone transport as a method of soft tissue preservation. J Limb Lengthen Reconstr 2019;5:100-4
| Introduction|| |
The management of traumatic limb injuries with major bone loss and soft tissue compromise remains a clinical challenge that requires reconstructive surgery to retain limb functionality.,,,,,, In the 1950s, Ilizarov introduced the method of distraction osteogenesis, revolutionizing the management of large bone defects. His method combines the advantages of circular external fixation of deformity correction, length control, early weight-bearing,, and the production of excellent bone regenerate while minimizing the risk of infection.,,,,, However, the method relies on externally fixed K-wires or half pins that lie perpendicular to the neurovascular structures.,,, They cause longitudinal scaring along the tract, posing a significant challenge when transporting a segment to an area with poor overlying skin or with a flap cover.,,
Previous studies have shown that scarring caused by the excursion of K-wires and half pins involved in the transport process can hamper the vascularity of the transported segment and increase the probability of treatment failure., In addition to soft tissue injury, the classical transport process is often painful and is complicated by pin-tract infections ,, and soft tissue invagination,,, making an already prolonged external fixation time more onerous for the patient.,,,
In 1998, Weber , proposed a bone transport technique that utilizes circular external fixation in combination with a central cable and pulley system to perform distraction osteogenesis., This technique allows parallel transport of a bone segment without excursion of transport elements through the skin or the soft tissue cover,, minimizing soft tissue compromise, patient discomfort, and potential pin-tract infection associated with the classical method.,, Since the method utilizes circular external fixation, it maintains the advantages of early weight-bearing and stable dynamic fixation.,
The purpose of this study was to describe our experience in using the Weber technique of cable bone transport in patients with severe bone loss and soft tissue injury, in an effort to preserve soft tissue cover and minimize soft tissue complications associated with classical Ilizarov bone transport. We emphasize the advantages of this method when transporting a bone segment to an area covered by a flap or a severely compromised soft tissue cover.
| Patients and Methods|| |
This is a retrospective study of a consecutive series of patients received between 2013 and 2018, during the years in which our hospital received >2000 injured Syrian civilians, five of whom had severe traumatic injuries requiring reconstructive surgery to salvage their limbs.
In total, six cases (five Syrians and one local) were treated with cable bone transport.
- Any patient who underwent bone transport using the Weber method due to bone loss caused by trauma or infection.
- Any patient who did not complete the bone distraction process or had a follow-up of <1 month after bone transport apparatus installation.
After receiving approval from our Institutional Ethics Committee, patients' records and imaging examinations were reviewed to determine the patient demographics, mechanism of and location of injury, type of fracture, amount of bone loss, cotrauma and associated injuries, number of surgeries, visual analog scale (VAS) scores, complications, osteotomy site, rate of distraction, quality of bone regenerate, infections, and treatment stages.
VAS scores were recorded from daily patient nursing reports, during the initial period of Ilizarov fixation and during the bone distraction process. Statistical analysis of VAS records was performed using the Wilcoxon signed-rank test.
After staged debridement and flap maturation, previous external fixation was removed, and surgical exposure was performed along previous incision lines or in collaboration with plastic surgeons when a flap covered the defect site. A antibiotic beads, if any were removed Debridement of necrotic tissue until punctate bleeding was seen and followed by irrigation of the wound. Cable is fixed proximal to fracture site [Figure 1] and passed percutaneously under the soft tissue or flap using a drainage tube with a guidewire. First, a drainage tube with a guide wire is passed beneath the skin distally from the fracture and osteotomy site. When the guidewire has reached the desired position and the tube is in place, the guidewire is removed, and the cable is inserted through the drainage tube and fixed to the distractor apparatus. This is done to the both ends of the cable, [Figure 2]f; note that the cables are attached parallel to the bone axis on a standard circular external fixator. This enables gradual and smooth distraction.
|Figure 1: Intraoperative image demonstrating cable insertion. Crossed drilled holes (interrupted lines) should not meet at the crossing. The cable was inserted through the medial hole then passed on the ventral surface of the bone creating a loop to be inserted into the second drilled hole (arrows)|
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|Figure 2: (a) X-ray of left ankle with total articulation loss, (b) Comminuted fracture of right ankle joint, and (c) compression fracture of Lumbar vertebrae L2-L4. (d) External fixation of left ankle joint. (e) Intraoperative X-ray of peroneal artery aneurism embolization. (f) Bone transport of left tibia according to Weber's method. (g) Circular external fixation of right ankle combined with open reduction and internal fixation using screws. (h and i) Bilateral X-ray of left (L) and right ankle (R) after circular external fixation removal, and left ankle arthrodesis|
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Coricotomy was performed on the transported bone segment. After the bone segment reached the docking site, a bone graft was applied, and the cable system was retained to perform compression.
| Results|| |
Between 2013 and 2018, six patients underwent bone reconstruction using the cable bone transport technique.
One case was excluded from the results since the patient discounted treatment before distraction was initiated; thus, the results are based on five cases.
The mean follow-up was 13.2 months (range: 1–33 months), the mean patient age was 24.8 years (range: 14–32 years), and there were four males and one female. The mechanism of injury was injury by blast explosions in four patients and a fall from height in one patient. The bones involved were three tibias, one femur, and one humerus. Two patients required soft tissue coverage; one was performed with a cross leg flap and the other with a latissimus dorsi flap. Two of the patients presented with total articulation loss (see case presentation).
Two cases arrived with a severe cotrauma. Two cases were treated elsewhere before referral to our institution; one arrived with an infected nonunion with a sinus tract and one with a pin-tract infection.
Two patients presented with a vascular injury, one with a combined injury involving popliteal and peroneal arteries with early signs of ischemic foot, which were managed by emergent reconstruction and embolization, respectively. The second case had a laceration of the peroneal artery that was embolized and closed.
Four out of five cases were war injuries and had an active infection upon arrival; all managed by radical debridement and intravenous antibiotics according to specific sensitivity.
The average defect size was 7.8 cm (range: 5–13 cm). The average number of procedures before osteotomy and cable placement was 4.4 (range 3–6).
All cases completed the bone distraction process with an average distraction index of 1.35 month/cm, bone regenerate was good in all cases, except in one case who was lost to follow-up a month after initiation of the distraction process.
Transport of bone segment caused no compromise to the soft tissue or flap cover. No infections or soft tissue complications were observed at the cable exist site. Flaps that were applied in two of the cases matured adequately and were not injured during the bone transport process.
VAS records during hospitalization were available for four patients; the average VAS was 5.24, with median of 5.12 during the period of external fixation before the process of bone transport. During bone transport, the mean and median VAS scores were 5.0 and 4.64, respectively. Statistical analysis of the data showed no statically significant difference between the results. All patients were able to ambulate with crutches a week after installation of the cable pulley system. Patients learned how to perform distraction at a set rate at home.
Due to geopolitical circumstances, four Syrian patients left treatment before docking healed. Two cases who remained in follow-up completed treatment having a mean external fixation time of 1.73 month/cm; external fixation time ranged from 15 to 18 months.
Complications were one case of pin-tract infection resolved by pin removal and antibiotic coverage and one case with shoulder spanning circular fixation with limited elbow movement, resolved with removal of apparatus and physiotherapy. One patient had re-fracture at the docking site.
A 20 years old female admitted after a fall from a height and suffered combined trauma to both legs and vertebral column. Injuries consisted of a burst fracture of L2-L4 without neurological compromise [Figure 2]c, an open fracture of the distal tibia and fibula of the left leg [Figure 2]a, with 5 cm bone loss, and a laceration of the peroneal artery, graded as Gustillo IIIB. The right leg suffered a closed comminuted fracture of the tibial pilon [Figure 2]b. Open fracture of the left leg was managed initially with debridement and external fixation [Figure 2]d. A day later, vertebral fixation was performed followed by peroneal artery embolization [Figure 2]e. A week after initial injury, circular external fixation was installed on the left leg with a cable system to transport the tibia [Figure 2]f. On the same day, the right tibial pilon underwent open reduction and internal fixation with screws and Ilizarov system fixation [Figure 2]g. Bone transport was completed with consolidation at the docking site after 10 months. A month after consolidation, the patient returned due to re-fracture at the docking site. Circular external fixation was reapplied, combined with bone graft, and arthrodesis using lag screws [Figure 2]h and [Figure 2]i.
A 32 year old male admitted after blast injury to the right shoulder area causing severe skin, muscle, and bone loss [Figure 3]a, [Figure 3]b, [Figure 3]c. Bone loss included humeral head and upper third of the shaft for a total of 13 cm bone loss. Neurovascular status was intact distally. Following staged debridement and external fixation, combined surgery of a latissimus dorsi flap and bone transport pulley system application were performed [Figure 3]d, [Figure 3]e, [Figure 3]f. The patient had pin-tract infection at a distal pin insertion site that was removed and treated with antibiotics until infection resolved. Treatment was completed after 18 months with glenohumeral arthrodesis using a plate [Figure 3]g. The patient had limited elbow movement initially which was managed by extensive physiotherapy and returned to full range upon discharge.
|Figure 3: Blast injury causing large skin and muscle defect (a and b). (c) Computed tomography three-dimensional reconstruction, demonstrating total proximal humerus loss. (d-f): Images after pulley-cable system application combined with flap. (g) Plate arthrodesis of glenohumeral joint|
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| Discussion|| |
Weber technique in our experience proved to be effective in producing excellent bone regenerate with minimal injury to surrounding soft tissue. Moreover, we found it a valuable tool in treating complex injuries with fragile or large soft tissue defect, especially with a flap in situ. This is reflected in the absence of soft tissue complications during the bone transport process, including minimal residual scaring, no increase in patient discomfort during transport and, most prominently, no flap-related complications. Bone regenerate was good in all despite the fact that two cases had vascular compromise upon arrival.
The preservation of soft tissue cover is paramount since it is critical for bone healing., It acts as a barrier to infections  and as a means to deliver antibiotics to the defect area. The classic method described by Ilizarov of bone transport can hamper the vascularity of the soft tissue cover or flap and hence the vascularity of the transported bone segment.,
Studies combining single-step Ilizarov system application with free vascular flap transfer encountered flap failure due to thrombosis. A study by Hollenbeck  that combined flap transfer with Ilizarov bone transport had a high flap survival; however 13% of cases required re-exploration to salvage the flaps. despite that, the author did not conclude that Ilizarov external fixation and subsequent distraction increased the risk of flap failure. Nonetheless, the authors recommended careful planning and cooperation between plastic and orthopedic surgeons.
The average external fixation time of 1.73 month/cm is commensurate with rates seen in the classic Ilizarov method  or modification of the transport system.,
The application of Weber bone transport system requires only stainless steel pulley rings and standard cables, 2 mm in diameter. The application of those rings should not be difficult for surgeons familiar with the Ilizarov system.
Since the bone segment is attached to cables bilaterally, it is prevented from wobbling, and with regular radiological follow-up, mal-alignment can be corrected with the alternation of cable pull. The method enables almost immediate weight-bearing, unlike the monolateral external fixator combined with cables as described by Baumgart  and Kucukkaya  further decreasing patient disability and discomfort.
The limitation of our study was a limited number of cases and that only two cases remained to complete the whole bone reconstruction process; in addition, the retrospective nature of the study and a lack of a comparison control group treated with the classic Ilizarov method might be subject to information bias. However, previously published articles using Weber method transport had less than two cases.,, A modification of the technique published by Demir  had nine cases. None of those studies combined the technique of Weber with flap coverage.
The aim of our study was to re-introduce techniques that can be applied in patients with fragile soft tissue cover and still be able to deliver excellent bone regenerate with no compromise to the surrounding soft tissue. We were able to apply the method to various clinical situations with no complications caused by the transport apparatus, despite being the soft tissue cover fragile after several repeated operations.
| Conclusion|| |
The Weber method is a reliable technique generating good-quality bone, while maintaining the integrity of soft tissue envelope, minimizing soft tissue complications associated with the classical method of bone transport. The Weber technique is especially valuable when bone transport is performed in a flap-covered area, where the excursion of half pins and K-wires can compromise flap survival.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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