Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Limb Lengthening (Ilizarov Method)

Basics
Description
  • The process of forming new bone by slow, gentle stretching is called distraction osteogenesis.
  • 1 method of lengthening was developed in Kurgan, Russia, by G. I. Ilizarov as a means of slowly and completely correcting many congenital and acquired abnormalities.
    • The Ilizarov method uses a versatile external fixator to produce gradual changes in the length and alignment of an extremity.
      • The fixator consists of circular rings attached to bone with wires.
      • These rings are distracted (spread apart) by threaded rods.
      • Each fixator is custom assembled for the given patient and indication.
  • Fixators other than the Ilizarov (versatile but tend to be bulky) may be used:
    • Monolateral fixators and spatial frames
    • If complex rotation and angular correction are not needed, fixators with PINS in a straight line may be used (many different models are available).
  • Nevertheless, the principles described here are general and apply not to the device but, rather, to the concept and procedure.
  • The Ilizarov method is applicable to all extremities, but it is used most commonly in the lower extremities where alignment is more critical than in the upper extremities.
  • The ideal age for performing the Ilizarov method is in the preteen and teen years.
    • At this time, the skeleton is almost finished growing, so its final shape can be determined, yet the potential for healing and remodeling is that of a child.
    • In addition, the patient has the maturity to undergo an arduous treatment process.
    • Bone healing, however, is slower with advancing age.
  • For certain indications, this procedure can be performed in younger patients (with severe congenital abnormalities) or in adults (with nonunions and acquired deformities).
  • Classification for types of procedures performed using with Ilizarov method:
    • Extremity lengthening
    • Angular correction
    • Repair of nonunion
    • Restoration of lost bone
    • Correction of contracture
    • Fracture treatment
  • Synonyms: Limb lengthening; Callotasis
Diagnosis
Signs and Symptoms
History
In deciding whether this treatment method is appropriate for a given individual, the physician should determine the degree of functional impairment, degree of patient adaptation, and degree of patient understanding and motivation to undergo a treatment that lasts for many months.
 
Physical Exam
The patient should be checked for pin-tract problems, nerve function, and joint ROM at each visit.
 
Treatment
Special Therapy
Physical Therapy
  • Patients may benefit from:
    • Instruction on appropriate weightbearing and transfers
    • Maintaining joint ROM
    • Strengthening
    • Monitoring the correction process daily
Medication
First Line
NSAIDs should not be taken for a long period because they may suppress bone healing.
 
Surgery
  • Surgery (to create the osteotomy and attach the fixator) is performed with the patient under general anesthesia (bone elongation usually is performed later).
  • The external fixator frame is assembled on the patient’s limb according to its shape and the goal of treatment.
    • Several PINS or rings are needed above and below the site of bone correction.
    • Threaded distraction rods are positioned to provide the needed correction over time.
  • The osteotomy is performed once the bone is stabilized.
    • Use a small incision.
    • Try to limit as much as possible the disruption of the blood supply.
    • Often, the fixator is extended to an adjacent bone for stability.
  • If the needed correction is minor, it can be performed while the patient is under anesthesia, but usually no distraction or lengthening is performed at the time of the surgery.
  • Distraction:
    • Started 7-10 days postsurgery (approximately the time the healing callus is 1st seen radiographically)
    • Continued at a rate of 1 mm per day:
      • Usually divided into at least 4 segments so the tissues are not stretched too suddenly
      • In this way, the callus is stretched slowly (distraction osteogenesis).
  • Once the desired length is achieved, the new bone is allowed to strengthen, which occurs with time and weightbearing.
  • The fixator is removed when the bone appears strong enough.
  • The total time spent in the fixator can be estimated by the lengthening index:
    • Time (per centimeter of length gained) needed for the process of lengthening and consolidation
    • Averages 1-1.6 months/cm
Follow-up
Prognosis
  • The results usually are good, although problems and complications may require additional procedures before completion.
  • An 80-90% success rate may be expected, although the healing time often is prolonged.
Complications
  • Nonunion
  • Joint stiffness or subluxation
  • Fracture
  • Nerve injury
Patient Monitoring
  • Patients must be seen periodically during the procedure to monitor the correction process and to check on the status of the pin sites.
  • Radiographs usually are necessary.
Miscellaneous
Patient Teaching
  • Patients should be told of the duration of treatment (usually many months).
  • They should be helped to make arrangements for school or work and for care after the procedure.
    • Admission to a rehabilitation hospital sometimes is indicated.
  • Patients should be assessed to determine whether they have the level of maturity needed for the treatment.
  • Patients may be allowed to bear weight and to swim with the device, if the surgeon allows.
FAQ
Q: Can young children undergo this process?
A: Yes, if the deformity or discrepancy is severe and is limiting them.
 
Q: How do I decide whether to undergo limb lengthening versus shortening of the other side?
A: The decision depends on the patient’s expected stature at adulthood and on the condition of the joints and muscles in each limb.
 
Q: Can the Ilizarov procedure be used to make me taller?
A: In certain circumstances, yes. However, the treatment time is long and must be applied to both limbs.

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