The Treatment of Thoracic Insufficiency Syndrome Associated with Fused Ribs and Scoliosis

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RM Campbell, Jr., MD*;
MD Smith, MD*;
TE Mayes, MD*;
JA Mangos, MD*;
DB Willey–Courand, MD*;
Ricardo Pinero, MD*;
Marden Alder, DDS*;
N Kose, MD†;
Hoa L. Duong, MD‡;
JL Surber, BS*
(a – National Organization of Rare Diseases, Office of Orphan Development of the FDA. C– Synthes Spine Company)
*San Antonio, TX, USA,
†Eskisehir, Turkey
‡Boston, MA, USA

Thoracic Insufficiency Syndrome (TIS) is the inability of the thorax to support normal respiration or lung growth. We have treated 34 patients with progressive congenital scoliosis associated with fused ribs of the concave hemithorax with an expansion thoracoplasty by an opening wedge thoracostomy of the concave hemi–thorax with lengthening by a chest wall distractor known as a titanium rib prosthesis with further secondary lengthening at 4 month intervals.

RESULTS:
16 patients with an average follow–up of 3.8 years (range 2 – 6yr) were studied. The average age at surgery was 2.3 yrs. One patient preop was on continuous CPAP with tracheostomy; at follow–up he had been weaned to room air. The remaining patients preop were on room air and remained so at follow–up. The average respiratory rate of all patients went from 36 br/min preop to 22 br/min postop. Average forced vital capacity (n = 7) was 54 % predicted normal. All patients had progressive scoliosis; average progression was 19 degrees. Average scoliosis preop was 73 degrees (35– 128); avg. improvement was 20 degrees (p<0.0001). Avg. thoracic kyphosis was 17 degrees preop with increase to 33 degrees postop. The treated curve was divided into 3 segments: a proximal flexible thoracic segment (F1), a central rigid thoracic curve (R) which did not change on bending films, and a distal flexible thoracolumbar curve (F2). Postop the F1 curve increased an avg. of 8 degrees, the avg. R curve decreased from 60 to 50 degrees and the distal F2 curve was unchanged. The arc of flexibility of the rigid curve changed from an avg. of 0 degrees preop to 10 degrees postop. Correction of the lateral shift of the spine was assessed by the ratio of the distance from the lateral pedicle at the apex of the curve to the theoretical normal pedicle location over the theoretical corrected interpedicular distance (NL equals one or less ). The avg. ratio improved from 2.5 to 1.9 (p<0.03) The avg. thoracic spinal height increase was 0.8 cm/yr. The avg. height increase of the operative hemi–thorax was 0.8 cm/yr; the unop. hemithorax ht increase was 0.6 cm/yr.(p<0.05).

COMPLICATIONS:
No complications in 17/34 patients. Four out of 34 patients had slow device cut–out through the rib, one spinal hook dislodgment, three transient UE neuropraxias, one spinal cord injury, two ARDS, two skin sloughs, one device infection, one transient postop pulmonary hypertension, and one post–operative death.

CONCLUSIONS:
Expansion thoracoplasty using a chest wall distractor directly treats segmental hemithorax hypoplasia from fused ribs, addressing thoracic insufficiency syndrome by lengthening and expanding the constricted hemithorax, indirectly correcting scoliosis in the young child primarily through the rigid segment of the curve without the need for spine fusion, with probable benefit for the underlying lung

* . · If noted, the author indicates something of value received. The codes are identified as: a–research or institutional support, b–miscellaneous funding, c–royalties, d–stock options, e–consultant or employee.