Expert’s comment concerning Grand Rounds case entitled “Management of cervical myelopathy due to ossification of posterior longitudinal ligament in a patient with Alström syndrome” (by Bronek M. Boszczyk, Rishi Mugesh Kanna and Daniela Gradil)

Abstract

The authors present an extremely rare case of Alström Syndrome who developed an extensive and serious ossification of spinal ligament [1]. Extensive ossification of both anterior and posterior longitudinal ligaments from C1 to T1 was observed with an occupying ratio more than 50 %, and combined with large osteophytes in front of vertebral bodies and ossification of ligament flavum from T1-3. Combined morbidity included sight and hearing loss, hepatic and renal dysfunction, hypertension, diabetes mellitus and polyarthritis. Progressive numbness in the finger tips was the chief complaint and further examination discovered weak hand grip and sensory loss below C5 dermatome, and positive myelopathic signs related to the spinal cord lesion. Posterior laminectomy from C3-6 without instrumentation was performed by the authors.Improved hand function and gait were observed after operation. Postoperative MRI demonstrated an excellent decompression of spinal cord.Severe OPLL is hard to deal with. The communication problem in this case provided extra difficulty to the operation, so did multiple combined morbidities. The authors should be praised for their great efforts in this case. I admired the final decision of a simple yet effective way with laminectomy alone. I would do the same for the patient.Matsunaga et al.[2] found 71 % patients of OPLL without original myelopathy lived myelopathy-free during a 30-years follow-up, and advocated that preventive surgery was not necessary for non-myelopathic patients. We observed some cases of OPLL without symptoms of myelopathy (or not diagnosed myelopathy) who were rendered quadriplegic and/or presented with dyspnea after minor trauma like slipping from a chair in sitting position or cycling on macadam. To prevent the catastrophic outcome, we have now accumulated more cases and look for risk factors that may indicate precautionary surgical treatment in non-myelopathic patients.For the surgical strategy of OPLL, controversies continue. Anterior corpectomy has the advantage of thorough decompression with removal of the ossified mass, which promises a better long-term result [3]. The major shortcoming of anterior approach (AA) is that it is not appropriate for very extensive lesion and that the fusion rate drops in that condition. An anterior approach is always considered as technically demanding. Posterior approach (PA) is preferred by some surgeons for safety and ease, but it could not provide adequate decompression of spinal cord in patients with preoperative kyphosis, and the results were not as good as AA, especially in massive ossification and in long follow-up. Mean improvement rate after operation