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.

Larsen Syndrome and Associated Spinal Deformities

“…Patients affected by Larsen syndrome frequently exhibit spine abnormalities that stem from various underlying deformities, such as hypoplasia of the vertebral bodies, hemivertebrae, or segmentation anomalies of the vertebrae [ 5 ]. A particular concern is the presence of deformities in the cervical spine, as it poses a significant risk for cord compression and can result in life-threatening complications [ 4 , 8 , 13 ]. One of the most severe indications of Larsen syndrome is the development of cervical kyphosis, a condition characterized by abnormal neck curvature, potentially resulting in the impingement of the spinal cord [ 7 , 16 ].…”

“…One of the most severe indications of Larsen syndrome is the development of cervical kyphosis, a condition characterized by abnormal neck curvature, potentially resulting in the impingement of the spinal cord [ 7 , 16 ]. This condition is associated with progressive instability, cervical cord myelopathy, distal muscle weakness/atrophy, and quadriplegia, making it a critical aspect in assessing and managing patients with Larsen syndrome [ 4 , 9 , 13 ]. It is essential to highlight that in certain cases, cord compression may not transpire at the level of the kyphotic deformity but rather at its adjacent levels, both cranial and caudal [ 22 ].…”

“…This gradient may result from the possible fusion of the kyphotic vertebrae, further complicating the case [ 22 ]. Research indicates that the occurrence of cervical kyphosis in those with Larsen syndrome is roughly 12% [ 4 , 9 ], and the likelihood of myelopathy is almost 15% [ 13 ]. Therefore, obtaining cervical spine radiographs immediately after diagnosing Larsen syndrome is pivotal, as early detection of cervical kyphosis and subluxation is imperative to prevent fatalities in these individuals [ 3 ].…”

“…The most appropriate course of action will depend on numerous factors, including the syndrome's specific presentation, the severity of the disease, and the age of the patient [ 8 , 10 ]. Posterior spinal fusion is only suggested for those presenting with mild and flexible cervical kyphosis [ 4 , 10 , 13 , 23 , 27 , 28 ]. For patients with severe or rigid kyphotic deformity who frequently develop myelopathy, anterior decompression and circumferential arthrodesis are the preferred option [ 4 , 10 , 13 , 23 , 27 , 28 ].…”

“…The onset of symptoms usually begins in early childhood or adolescence [ 2 ]. This condition is classified as osteochondrodysplasia [ 3 , 4 ].…”