Abstract
Background The complex ranges from mild epispadias to devastating cloacalexstrophy. Affected babies require multidisciplinary care. The orthopaedic surgeon may assist either directly, in releasing the midline by pelvic osteotomies or indirectly, by advice and treatment of musculoskeletal symptoms related to disturbed mechanics or deformity in the spine, pelvis and lower limbs.
Traditional osteotomies are posterior or horizontal. A technique of an oblique osteotomy from the sciatic notch to the iliac crest has been developed at Great Ormond Street since 1996, along with a system of external fixation. It is undertaken concurrently with urological reconstruction. The system of external fixation is relatively simple compared with other published work.
Methods We reviewed the results of 45 oblique osteotomies performed in conjunction with genito-urinary repair of classical and cloacal bladder exstrophy. Average follow-up was 37 months. Clinical outcome measures were pain, function, continence and normal gait. All radiographs were reviewed and the pubic intersym-physeal diastasis was recorded pre-operatively and on the latest post-operative x-ray. Children were grouped according to the age at the time of osteotomy.
Also children with classical exstrophy were divided into 4 groups on the basis of continence.
The mean post-operative percent reduction in the amount of the original diastasis was determined for all age groups. Comparison of pubic approximation was made between the two types of post-operative immobilisation
Results The majority of patients (42) reported no pain or functional disability. Six cases had a waddling gait pattern and 2 had residual external rotation. All the wounds healed and every osteotomy united.
The average improvement in pubic approximation was 37% for the whole series. Chidren who were older at the time of surgery (18–60 months) were found to maintain better correction over time (76%).
Children immobilised with an external fixator maintained better closure of the pelvis than those treated with plaster cast alone. (51% and 12.2% respectively). Maintenance of pubic approximation was associated with a higher level of bladder continence.
Complications included 3 cases of infection and loosening of the external fixator requiring early removal. There were no neurovascular complications.
Conclusion Oblique pelvic osteotomy is an effective part of the reconstruction bladder exstrophy and compares well with other types of osteotomy.
It is a reliable operation and the technique is applicable to all age groups.
Technique of Oblique Pelvic Osteotomy Oblique pelvic osteotomy is performed by first placing the patient in the supine position, preparing and draping the lower part of the body from the costal margin to the mid-thigh. Intravenous antibiotic prophylaxis is administered and continued for a 24-hour period.
Initially the Urologist will make an infra-umbilical incision then identify and mobilise the anatomical structures intended for their subsequent reconstruction and repair. This wound is then temporarily closed.
The Orthopaedic surgeon will then approach the ilial crest through bilateral oblique incisions made inferior to the anterior superior ilial spine as described for the Salter osteotomy
The interval is developed distal to the anterior superior ilial spine after identification and protection of the lateral femoral cutaneous nerve which is taken medially. After the interval between sartorious and tensa fascia lata are identified the iliac apophysis is split and reflected off the inner and outer ilial crests. The exposure may be improved by also developing the interval between rectus femorus and gluteus medius. Each side of the pelvis is exposed sub-periosteally from the iliac crest extending into the sciatic notch.
A Gigli saw is then passed through the sciatic notch. The line of the osteotomy is from the posterior part of the sciatic notch extending anteriorly and superiorly to exit the iliac crest 2cm posterior to the anterior superior iliac spine (figure 2). The most anterior 1.5cm of iliac crest from the distal pelvic fragment is trimmed to allow closure of the iliac apophysis after rotation.
The size of the half pin utilised is determined by the age of the patient. A baby under 18 months old will have a 3.5mm pin from the AO wrist external fixator frame and an older child over 2 years, a 4.5mm half pin. One half pin is inserted on each side of the pelvis. The half pin is placed in the distal fragment from anterior and lateral to posterior and medial with the tip of the screw just exiting the cortical bone of the medial aspect of the sciatic notch (figure 3a). Consideration of pin placement must take into account rotation of the distal fragment and preventive skin pressure areas. The iliac apophysis is repaired and the skin wounds are closed.
The Urologist completes the reconstruction procedure planned via their infra-umbilical approach.
The final stage involves the medial and superior rotation of both distal pelvic fragments and subsequent closure of the symphyseal diastasis. This position is maintained with the application of an anterior A-shaped frame from the wrist, AO fixation set in the younger infant or the AO pelvic fixator in the older child (figure 3b).
Symphyseal approximation is confirmed intra operatively by palpatation. Bilateral above knee front slabs casts are applied to prevent kicking the hips or knees.
The post-operative management involves pin site care on alternate days. The front slab casts are removed at 3 weeks and the anterior A-frame is removed at 6 weeks after union is confirmed on a pelvic radiograph. Depending on the social situation the children may go home during the post-operative period.
The abstracts were prepared by Mr Jerzy Sikorski. Correspondence should be addressed to him at the Australian Orthopaedic Association, Ground Floor, William Bland Centre, 229 Macquarie Street, Sydney NSW 2000, Australia.
