gms | German Medical Science

Objective: Besides the shift to less invasive surgical approaches in the management of CM1/1.5 the notion persists that decompression with shrinking of the tonsils and duroplasty is more effective compared to pure bony removal. We review our experience with both surgical approaches for treating CM1/1.5 in children.

Methods: Patients (≤18 y) who received cranio-cervical junction decompression with and without dural opening (suboccipital craniectomy, C1-laminectomy, +/- duroplasty and tonsil-shrinking) for CM1/1.5 (1/2015–7/2018) were reviewed. Records were analyzed for clinical symptomatology, neurological status, polysomnography (PSG), and electrophysiology. Pre- and post-surgical MRI was reviewed for cerebellar tonsil herniation, syringomyelia, width of the foramen magnum (FM). Surgery was performed in standard manner. Decompression was evaluated via intraoperative ultrasound.

Results: 28 patients were included (bony only (A): 16; dural opening: 12 (B)). Mean age was 11y+5 (8 m, 8 f) in (A); 10 y±4,7 (6 m, 6 f) in (B). Pre-operative mean tonsillar herniation at presentation was 17,75±6,94 mm (range 7 to 28 mm) (A) and 15,9±5,1 mm (8 to 25 mm) (B). Symptoms in both groups included the whole spectrum of CM1/CM1.5 i.a. suboccipital headaches, syrinx, central sleep apnea, sensorimotor deficits. No patient exhibited papilledema or cervical instability. In all but 2 patients of group A surgery resulted in improvement or resolution of symptoms, incl. nuchalgia, central apnea syndrome and others. In all cases who presented with pre-operative scoliosis there was arrest or improvement of angulation. In (A) tonsils ascended in 7/16 cases (mean herniation post-op 14±7,6); after dural opening and tonsil shrinkage herniation improved in all but one cases (mean 7.5±5.5 mm). There was no difference between the treatment groups regarding bony FM decompression (mean difference pre/post-surgery: 14.20+4.13 and 14+4.5 mm; sagittal MRI images). Improvement in syringomyelia was seen in 2 (A) vs. 7 (B) cases. In both groups no postoperative complications occurred. Repeat surgery was performed in 2 group A patients due to persistent complaints.

Conclusion: Albeit imaging-wise dural-opening and tonsillar shrinkage resulted in more obvious improvements, regarding clinical features bony-only decompression can be viewed a save fist-line option for treating symptomatic CM1/1.5.