Minimally Invasive Surgery for Neuromuscular Scoliosis

Results and Complications at a Minimal Follow-up of 5 Years

Mathilde Gaume, MD; Claudio Vergari, MD; Nejib Khouri, MD; Wafa Skalli, MD, PhD; Christophe Glorion, MD, PhD; Lotfi Miladi, MD

Disclosures

Spine. 2021;46(24):1696-1704. 

In This Article

Results

Demography

Of the first 100 patients, six were lost of follow-up and 11 died of independent causes from spinal surgery. As such, 83 patients (83% of the initial number of patients) were included (40 females, 43 males). All patients were Risser stage 0 at initial surgery with a mean age of 11.5 years (5.2–15.4). The diagnoses were cerebral palsy (n = 45), spinal muscular atrophy (n = 21), muscular dystrophy (n = 10), and other neuromuscular disorders (n = 7). Mean follow-up was 6.5 years (5.3–9.0). Thirteen patients were ambulatory. Mean body weight was 24.4 ± 6 kg preoperatively and 37.3 ± 7 kg at latest follow-up. (Table 1)

The average operative time for the initial surgery was 2 hours 26 minutes (from 1 hour 33 minutes to 3 hours 39 minutes; the average operative time for rod lengthening was 44 minutes (from 26 minutes to 1 hour 10 minutes.

Twenty-four percent of patients required one to two blood transfusions at initial surgery, none after rod lengthening.

Radiological Outcomes

Table 2 and Table 3 report the changes in these radiological parameters.

Seventeen patients did not require rod lengthening thanks to a stable and satisfying correction after initial surgery. The other patients underwent one rod lengthening (30), two rod lengthening (24), three rod lengthening (11), or maximum four rod lengthening (1) to achieve progressive correction of spinal deformity and/or pelvic obliquity.

Screw loosening was visible radiographically in 17 patients (seven ambulatory and 10 nonambulatory) (Figure 1) No clinical or mechanical consequences of osteolysis were seen in any patients, and no revision was needed.

Figure 1.

Screw loosening around iliosacral screw.

At last follow-up, skeletal maturity (Risser stage 4) was reached in 42 of 83patients (50.6%) with a mean of 2.9 ± 1.4 years after initial surgery. Mean Cobb angle was 34.5° (min 6.4° to max 51.7°) and mean pelvic obliquity was 7.4° (min 0° to max 20.3°). At last follow-up, none of these patients has required PSF with a mean interval of 3.7 ± 1 year after skeletal maturity.

Complications

Twenty-seven complications (12 mechanical and 15 infections) occurred in 26 of 83 patients corresponding to a global rate of 31%. Table 4 details the 12 mechanical complications and 15 infections requiring unplanned surgery.

Mechanical Complications

Mechanical complications included three cases of proximal hook migration, four cases related to the malposition of iliosacral screw, and five cases of rod breakages.

Rod breakages occurred in a mean interval of 4.0 ± 1 year after initial surgery and were located at lumbar area. Of these patients, pattern curves were thoracolumbar left (three), thoracolumbar right (one), and double major (one) with no significant difference compared with the rest of the cohort (P > 0.05). All patients suffered from cerebral palsy with severe dystonia or hyperactivity. Mean body weight of these five patients was 43.3 ± 6 kg (P = 0.04) and one of them was a walking patient.

Infectious Complications

Of the 15 wound infections, three occurred within the first 3 months of the initial surgery and 12 after rod lengthening procedures. Eleven were successfully treated by irrigation and debridement, with appropriate antibiotic therapy. Four patients required implant removal because of chronic infection: two of them necessitated a new instrumentation 1 year later because of a deformity worsening; the two others did not need new implantation thanks to a stable correction of the deformity. There was significant difference related to mean body weight and age at initial surgery compared with the other patients of the cohort. Most of patients (11/15) suffered from cerebral palsy with a significant difference (P = 0.039).

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