The Three Dimensional Evolution of Scoliotic Curvature During Instrumentation without Fusion in Immature Patients

Emre Acaroglu,
Ahmet Alanay,
Muharrem Yazici,
Adil Surat Sihhiye,
Ankara, Turkey

PURPOSE:
To evaluate the evolution of scoliotic curves until definitive fusion in immature patients that had undergone single rod distraction instrumentation without fusion (SCR).

PATIENTS AND METHODS:
Twelve patients who had been followed till definitive fusion were retrospectively evaluated. Patients were evaluated for any changes in the magnitude of their deformities in frontal, sagittal and transverse planes. Average patient age was 5.8±2.4 years at the time of SCR, and 11.3±1.6 years at definitive surgery. Average follow–up was 5.5±1.9 (2–8,5) years.

RESULTS:
It was seen that average number of lengthening operations per patient was 4.6±1.8 (2–7), number of all operations per patient was 7.1±2.6 (4–13). Average number of complications per patient was 1.9±2.2 (0–6). Average time spent in hospital was 104±69 (30–262) days. A summary of results can be seen on Table 1.

Ave±SD (range)(0)	Pre–SCR	Pre–def.surg	% change during SCR	Post–def.surg
Fro. Cobb	58.7±12.2 (40–90)	59.6±12.1 (45–78)	7.4±18.8 (–27 – 35)	34±7.7 (22–45)
Apical rot.	20.2±7.3 (10–35)	33.2±5.2 (25–42)	42.6±18.3 (0–67)
Th. Kyph.	30.1±10.7 (10–48)	40.9±9.8 (20–52)		41.8±10.9 (25–55)
Lum. Lord.	39.7±11.6 (24–65)	47.8±16.3 (18–80)		50.3±7.1 (40–60)

Average curve flexibility index was 46.7±10 at the time of SCR. At definitive surgery an average of 3.3±2.7 posterior osteotomies were required so as to obtain any flexibility, because of facet ankylosis.

DISCUSSION:
Our findings demonstrate that, the curves were essentially unchanged in the frontal plane during the period of lengthenings. The sagittal curves remained mostly within the limits of normal, but there was an alarming increase in rotation. Curves could be corrected to the level obtained at first SCR operation at the time of definitive surgery. Definitive surgery following SCR is very complex and requires facet osteotomies at multiple levels, yielding only 41.4% correction. It was concluded that, SCR with a single distraction rod was effective in preserving the frontal deformity for an average of 5.5 years, but was ineffective in controlling any increases in transverse plane deformity.