Craniovertebral junction instability in Larsen syndrome: An institutional series and review of literature

Abstract

Objective: Larsen syndrome (LS) is characterized by osteo-chondrodysplasia, multiple joint dislocations, and craniofacial abnormalities. Symptomatic myelopathy is attributed to C1-C2 instability and sub-axial cervical kyphosis. In this article, we have analyzed the surgical outcome after posterior fixation in LS with craniovertebral junction instability.

Methods: Ten symptomatic pediatric patients, operated between 2011 and 2019, were included, and the clinical outcome was assessed by Nurick grade, neurological improvement, and complications. The requirement of anti-spasticity drugs, the degree of bony fusion, and restriction of neck movement were also noted. At last follow-up, patient satisfaction score (PSS) and back to school status were studied. We also reviewed the literature and categorized two types of presentation of reported LS patients and discussed the pattern of disease progression among both.

Results: Ten patients, age range 1.5-16 years, underwent 12 surgeries (6 C1-C2 fixation, 4 long-segment posterior cervical fixation, and 2 trans-oral decompressions as the second stage); the mean follow-up was 23 (range, 6-86 months). All the ten patients in our study had the characteristic "dish-" like face and nine patients had acral anomalies. The median Nurick grade improved from preoperative (median = 4) to follow-up (median = 3). The requirement of anti-spasticity drugs decreased in seven patients and the neck-pain improved in nine patients. The median satisfaction at follow-up was good (median PSS = 2); five patients were going back to school.

Conclusion: Craniovertebral junction instability in LS is rare and surgically challenging. Early posterior fixation showed a promising outcome with a halt in the disease progression.

Keywords: Cervical kyphosis; Larsen syndrome; cranio-vertebral junction anomalies; long segment fusion; sub-axial compression; syndromic atlantoaxial dislocation.

Figure 1

A patient of Larsen syndrome (a) with computed tomography sagittal view showing bullet-shaped subaxial vertebral bodies (b)

Figure 2

Magnetic resonance imaging sagittal T2-weigted imaging (a) of a patient with “dish facies (b); the sagittal computed tomography showing os odontoidium and bullet shaped subaxial vertebral bodies (c). The three-dimensional computed tomography show facetal dislocation and bifid posterior arch of axis (d). Postoperative three-dimensional computed tomography scan showing long long-segment fixation (e)

Figure 3

A patient of Larsen syndrome with “dish-like” facial features (a); three-dimensional computed tomography sagittal view (b) and preoperative magnetic resonance imaging sagittal view (b) showing os-odontoidium with subaxial (C-6) vertebral body collapse with compression at craniovertebral junction; three-dimensional computed tomography reflected vertebral artery anomaly (right side vertebral artery hypoplasia with black arrow) (d); the postoperative CT scan showing long-segment cervical fixation with correction of cervical kyphosis and widened canal diameter at C6 level (e and f), and intra-operative photograph (g) showing long-segment fixation. The picture-in-picture shows X-ray immediately after surgery showing straightening of cervical spine