Cole Tyler S, Almefty Kaith K, Godzik Jakub, Muma Amy H, Hlubek Randall J, Martinez-Del-Campo Eduardo, Theodore Nicholas, Kakarla U Kumar, Turner Jay D
J Neurosurg Spine. 2020 Feb 7;32(6):907-913. doi: 10.3171/2019.10.SPINE19685. Print 2020 Jun 1.
Cervical spondylotic myelopathy (CSM) is the primary cause of adult spinal cord dysfunction. Diminished hand strength and reduced dexterity associated with CSM contribute to disability. Here, the authors investigated the impact of CSM severity on hand function using quantitative testing and evaluated the response to surgical intervention.
Thirty-three patients undergoing surgical treatment of CSM were prospectively enrolled in the study. An occupational therapist conducted 3 functional hand tests: 1) palmar dynamometry to measure grip strength, 2) hydraulic pinch gauge test to measure pinch strength, and 3) 9-hole peg test (9-HPT) to evaluate upper extremity dexterity. Tests were performed preoperatively and 6-8 weeks postoperatively. Test results were expressed as 1) a percentile relative to age- and sex-stratified norms and 2) achievement of a minimum clinically important (MCI) difference. Patients were stratified into groups (mild, moderate, and severe myelopathy) based on their modified Japanese Orthopaedic Association (mJOA) score. The severity of stenosis on preoperative MRI was graded by three independent physicians using the Kang classification.
The primary presenting symptoms were neck pain (33%), numbness (21%), imbalance (12%), and upper extremity weakness (12%). Among the 33 patients, 61% (20) underwent anterior approach decompression, with a mean (SD) of 2.9 (1.5) levels treated. At baseline, patients with moderate and low mJOA scores (indicating more severe myelopathy) had lower preoperative pinch (p < 0.001) and grip (p = 0.01) strength than those with high mJOA scores/mild myelopathy. Postoperative improvement was observed in all hand function domains except pinch strength in the nondominant hand, with MCI differences at 6 weeks ranging from 33% of patients in dominant-hand strength tests to 73% of patients in nondominant-hand dexterity tests. Patients with moderate baseline mJOA scores were more likely to have MCI improvement in dominant grip strength (58.3%) than those with low mJOA scores/severe myelopathy (30%) and high mJOA scores/mild myelopathy (9%, p = 0.04). Dexterity in the dominant hand as measured by the 9-HPT ranged from < 1 in patients with cord signal change to 15.9 in patients with subarachnoid effacement only (p = 0.03).
Patients with CSM achieved significant improvement in strength and dexterity postoperatively. Baseline strength measures correlated best with the preoperative mJOA score; baseline dexterity correlated best with the severity of stenosis on MRI. The majority of patients experienced MCI improvements in dexterity. Baseline pinch strength correlated with postoperative mJOA MCI improvement, and patients with moderate baseline mJOA scores were the most likely to have improvement in dominant grip strength postoperatively.
脊髓型颈椎病（CSM）是成人脊髓功能障碍的主要原因。与CSM相关的手部力量减弱和灵活性降低会导致残疾。在此，作者使用定量测试研究了CSM严重程度对手部功能的影响，并评估了手术干预的效果。
33例接受CSM手术治疗的患者被前瞻性纳入研究。一名职业治疗师进行了3项手部功能测试：1）手掌测力计测量握力，2）液压捏力计测试测量捏力，3）9孔插钉测试（9-HPT）评估上肢灵活性。测试在术前和术后6-8周进行。测试结果表示为：1）相对于年龄和性别分层规范的百分位数，以及2）达到最小临床重要差异（MCI）。根据改良日本骨科协会（mJOA）评分将患者分为轻度、中度和重度脊髓病组。术前MRI上狭窄的严重程度由三名独立医生使用Kang分类法进行分级。
主要症状为颈部疼痛（33%）、麻木（21%）、失衡（12%）和上肢无力（12%）。在33例患者中，61%（20例）接受了前路减压，平均治疗节段数为2.9（1.5）个。基线时，mJOA评分中等和较低（表明脊髓病更严重）的患者术前捏力（p<0.001）和握力（p=0.01）低于mJOA评分高/轻度脊髓病的患者。除非优势手捏力外，所有手部功能领域术后均有改善，6周时MCI差异在优势手握力测试中为33%的患者，在非优势手灵活性测试中为73%的患者。基线mJOA评分为中等的患者比mJOA评分低/重度脊髓病（30%）和mJOA评分高/轻度脊髓病（9%，p=0.04）的患者更有可能在优势手握力方面有MCI改善。9-HPT测量的优势手灵活性在脊髓信号改变的患者中<1，在仅蛛网膜下腔受压的患者中为15.9（p=0.03）。
CSM患者术后力量和灵活性有显著改善。基线力量测量与术前mJOA评分相关性最佳；基线灵活性与MRI上狭窄的严重程度相关性最佳。大多数患者在灵活性方面有MCI改善。基线捏力与术后mJOA MCI改善相关，基线mJOA评分为中等的患者术后最有可能在优势手握力方面有改善。
