1. Aetna considers the Ilizarov method for distraction osteosynthesis medically necessary for members who meet both of the following selection criteria:
   1. Member has one of the following indications for the Ilizarov procedure:
      1. Limb length discrepancies with or without an associated deformity; or
      2. Bone defects with or without an associated deformity; or
      3. Angular/rotational deformities of the long bones; and

   2. Any of the following selection criteria is met:
      1. Member has a leg length discrepancy of more than 6 cm; or
      2. Member has an arm length discrepancy of more than 5 cm; or
      3. Member has a fracture of a long bone that has not healed in 6 or more months, and has tried and failed electrical stimulation (see CPB 343 - Bone Growth Stimulators) and bone grafting (see CPB 411 - Bone and Tendon Graft Substitutes and Adjuncts); or
      4. Member has an angular/rotational deformity of the long bones resulting in functional impairment, and has failed other treatments.

2. Aetna considers the use of the Ilizarov method to correct short stature as cosmetic.

3. Aetna considers the Ilizarov method experimental and investigational for all other indications.

Notes: Insertion of wires and subsequent osteotomy of the affected limb are performed in the hospital. Removal of the device can be performed in the office/clinic; thus, hospitalization to remove the device is not necessary.

See also CPB 549 - Distraction Osteogenesis for Craniofacial Defects.

Distraction osteosynthesis refers to a technique in which a limb is gradually lengthened at a controlled rate across the osteotomy site.  The original limb lengthening procedure was first described in the English orthopedic literature by Codvilla (1905).  In the 1960s, the Wagner method (limb lengthening with cancellous bone grafting and plating of the distraction gap) was introduced into North America, and became the mainstay of limb lengthening in the United States for many years.  In this technique, an open mid-diaphyseal osteotomy is carried out across the periosteum, endosteum, and cortex resulting in a 0.5 to 1 cm diastasis.  This is followed by the placement of an external fixation system secured by screws in both the proximal and distal metaphyses.  Distraction commences immediately following placement of the fixator.  The distraction rate is traditionally set at 1.5 to 2 mm per day.  Following attainment of the desired distraction length, iliac crest cancellous bone is grafted into the diastasis in a second operation.  The affected bone is plated, and the external distractor is removed.  The operated limb does not bear weight for an extended period of time to allow for incorporation of the graft.  In a third operation, the plate is removed, and the subject is put on protective weight bearing (Wagner, 1978; Hood and Riseborough, 1981).

A less invasive technique for distraction osteosynthesis was developed by a Russian orthopedist Gavriil Abramovich Ilizarov in the 1950s.  His work was introduced to Italy in the 1980s as a result of the former Soviet Union's policy of glasnost, and later to the United States (Frankel et al, 1988).  According to Ilizarov's principle of "tension stress", bone and soft tissue will heal and regenerate in a predictable fashion under tension.  The Ilizarov procedure comprises 4 phases: (i) corticotomy (a special type of percutaneous osteotomy) and placement of an external fixation system, (ii) latency period, (iii) distraction, and (iv) consolidation.  This method has been employed to treat a wide variety of bone defects including limb lengthening while correcting concurrent associated angular and rotational malalignments, transporting bone segments to fill fracture gaps, and healing non-union fractures.  Compared to other alternatives such as the Wagner technique, the Ilizarov method requires only one surgical procedure and appears to have fewer complications.  Additionally, the Ilizarov procedure allows for simultaneous correction of multiple deformities, early movement of adjacent joints, as well as early weight bearing (Do and Sadove, 1992; Simard et al, 1992).

Cattaneo et al (1993) described the use of the Ilizarov procedure to 97 humeri on 75 patients, with 68 lengthening in 46 patients (27 males and 19 females, average age of 16.5 years) and 29 treatments for non-union in 29 patients (17 males and 12 females, average age of 46 years).  For patients who underwent humeral lengthening, results were considered excellent if the projected lengthening was attained, or in the cases of length discrepancy, less than a 3-cm length discrepancy remained, or if axial alignment was acceptable (less than 10 degrees angulation), and scars were minimal.  Furthermore, pre-operative function had to be maintained.  Outcomes were deemed good if there was only minimal functional loss, and poor if there was a limb discrepancy of greater than 5 cm, angulation of more than 10 degrees and significant loss of function, or a permanent neurological injury.  For patients who had treatments for humeral nonunion, consolidation was considered an excellent result, whereas persistence or recurrence of nonunion was considered a poor result.  Duration of treatment ranged from 5 to 14 months.  Forty-two (91.3 %) of the 46 patients who had undergone humeral lengthening had excellent results, 3 (6.5 %) had good results, and the remaining 1 (2.2 %) had a poor result as a consequence of reduced shoulder motion.  There were no major complications associated with this procedure.  For patients who underwent treatments for humeral nonunion, 25 (86.2 %) of 29 humeri healed, and 4 (13.8 %) remained ununited.  Of these, there were 3 patients aged 55, 70, and 79 years, and 1 patient with irradiated bone.  Results of this study indicated that the Ilizarov procedure is effective in humeral lengthening as well as in the treatment of humeral non-union.

Cierny and Zorn (1994) compared conventional methods with the Ilizarov procedure in the treatment of 44 patients with segmental tibial defects.  Patients were divided into 2 groups: (i) 21 long bone defects (segmental defects averaged 6.5 cm) were reconstituted by means of transport (part of the Ilizarov procedure that entails sliding a bone fragment internally, producing distraction osteogenesis behind the defect until it is bridged) or distraction methodologies according to the Ilizarov technique, and (ii) 23 subjects (segmental defects averaged 8.5 cm) underwent conventional treatment of reconstruction using tissue transfers and transpositions, massive cancellous grafts, and combinations of internal and external fixation.  Total wound consolidation and infection arrest occurred after the first treatment in 71 % of the Ilizarov wounds, and 74 % of the conventionally treated wounds.  The major complication rate for the Ilizarov group was 33 %, while that for the conventionally treated group was 60 %.  The overall success rate (95 %) were the same for both groups.  However, the Ilizarov group averaged 9 fewer hours in the operating room, 23 fewer days in the hospital, 5 fewer months of disability times, and a saving of nearly $30,000 per application.  These findings indicated that the Ilizarov procedure is faster, safer, and less expensive approach than conventional methods for the treatment of segmental tibial defects.