Modified Z-Plasty for Cervical Spine Myelopathy: A Not-So-Obsolete Method of Laminoplasty

Author(s): Truc Tam Vu, Hanh The Nguyen, Riet Ngoc Do, Thanh Dang Le, Vien Chi Tieu, Tram Thi Bao Nguyen, Khai Dang Tran, Lan Hoang Bui, Tuan Duc Ha, Long Thanh Ngo, Phuc Nghia Diep, Tin Trong Nguyen

Introduction: It is generally accepted that laminoplasty is a safe and reliable surgical treatment for cervical spine myelopathy (CSM) due to spinal canal stenosis. There are multiple techniques of laminoplasty for spinal cord decompression and most of them require expensive instruments to stabilize the laminae. From 2005 to 2015, we applied the modified Z-plasty (Sakou's technique) for CSM patients in an attempt to reduce the cost of treatment.

Materials and methods: This is a retrospective study. CSM patients treated by modified Z-plasty technique were selected. We applied the Sakou’s technique, according to which the laminae will be opened in different directions alternatively. We use the JOA score and recovery rate of Hirabayashi to assess the neurological recovery and the Neck Disability Index (NDI) for the cervical functional outcome.

Results: There were 42 patients with the mean follow-up duration of 10 years (5-15 years), male: female ratio of 3:1 and mean age of 61. The mean operating time and blood loss per lamina were 40 minutes and 45ml, respectively. The canal expanding index was 4.2mm (3-5 mm). The mean pre- and postoperative JOA score were 11.1 and 14.7, respectively (p<0.05). For the axial pain, the mean NDI was 18 point with 88% of cases having as good and very good cervical function. For complications, there were 3 cases of C5 palsy with full recovery after one year.

Conclusion: Being considered as an old-fashioned surgery, the modified Z-plasty can still provide good clinical and radiological outcomes to cervical myelopathic patients. The absence of hardware such as titanium plates or hydroxyapatite spacers reduces the risk of infection and the cost of treatment. Considering the risk-benefit and cost-benefit ratio, this operation is suitable for low-income patients in developing countries.