Mid-term clinical outcomes of anterior cervical internal fixation and fusion for Hirayama disease / 中华骨科杂志

ABSTRACT

Objective　To assess the mid-term clinical and radiological outcomes of anterior cervical internal fixation and fusion for the treatment of Hirayama disease and to evaluate the clinical significance and value of this procedure.Methods　All of 31 patients underwent anterior cervical internal fixation and fusion were retrospectively analyzed with a minimum of 5 years follow-up in our hospital between May 2008 and May 2011,whose disease progressively deteriorated after six-month's conservative therapy(neck collar)preoperatively.There were 30 males and 1 female with an average age of 19.0±2.7 years which ranged from 16 to 27.The clinical outcomes included forearm and hand muscle atrophy and strength.The radiological outcomes included range of motion(ROM)of the whole cervical spine and unstable segments,as well as venous flow empty phenomena and "snake eyes" sign on MRI in the flexed position.All were recorded at 3 month,1 year,3 year and 5-6 years follow-up time points after surgery.The preoperative and postoperative quantitative variables were analyzed by paired t test,and a P<0.05 was used to indicate statistical significance.Results　All the patients showed no further progression of symptoms of muscular weakness or atrophy.At the end of 5-6 years follow-up,24 of the 31 patients(77.4%)showed improved muscle strength and 16 of the 31 patients(51.6%)showed improved atrophy.Thirty-one patients had a forearm muscle strength of 4 to 5 at the last follow-up,with an average of 4.9±0.3,which was superior to preoperative 0 to 5(3.6±1.0);grip strength was 3 to 5 kg,with an average of 3.9±0.7 kg,significanthigher than 1 to 3.8 kg(2.5±0.8 kg)before surgery.Score of muscle strength of the 31 patients at the end of 5-6 years' follow-up was 4.9±0.3(4 to 5),which was significantly higher than preoperative.Postoperative X-rays at the end of 5-6 years' follow-up revealed that all the cases' internal fixation was at the proper position,and no losing or broken of the internal fixation were identified.Dynamic X-rays of cervical spine showed the range of motion(ROM)of the whole cervical spine was significantly decreased after the operation.The ROM of preoperation was 77.8o±12.70 and that of 5—6 years postoperation was 27.90±7.60.The unstable segments of cervical spine became stable postoperatively.The flexible position MRI of cervical spine showed the spinal cord was completely relieved,without new compression.Venous flow empty phenomena disappeared and no "snake eyes" sign was identified.Conclusion　Anterior cervical internal fixation and fusion is an effective surgical treatment for Hirayama disease and may provide preferable mid-term clinical and radiological outcomes.This procedure has clinical significance and value in terms of control of the progression and outcome of this disease.