Background:Paralabral cysts at the spinoglenoid notch are rare disorders that can potentially lead to compressive suprascapular neuropathy. Given their infrequency, a standard treatment protocol has not yet been established.Hypothesis/Purpose:This study aimed to assess changes in the infraspinatus muscle using magnetic resonance imaging (MRI) and to compare the outcomes of 2 different surgical methods. It was hypothesized that surgical intervention could alleviate compressive neuropathy, with comparable outcomes between the 2 surgical approaches.Study Design:Cohort study; Level of evidence, 3.Methods:This retrospective review encompassed 43 patients undergoing arthroscopic labral repair for a paralabral cyst at the spinoglenoid notch, with cyst decompression (27 patients; labral repair with cyst decompression [LRCD] group) or without cyst decompression (16 patients; labral repair only [LRO] group). Preoperative MRI focused on evaluating the condition of the infraspinatus and teres minor muscles. Electromyography (EMG) was conducted on 36 patients (21 in LRCD and 15 in LRO) to assess suprascapular nerve function. Postoperative evaluations were performed in 35 patients at postoperative 1 year, excluding those lost to follow-up. Postoperative MRI findings (24 patients in LRCD and 11 patients in LRO) and functional outcome scores including recovery of external rotation power were compared with preoperative status in both groups.Results:Preoperative MRI revealed denervation changes or atrophy of the infraspinatus in 26 of the 43 patients (60.4%). Among the 36 patients who underwent preoperative EMG, 21 patients (58.3%; 13 patients in LRCD and 8 patients in LRO) showed evidence of suprascapular neuropathy. A discrepancy between EMG and MRI findings was noted in 10 patients, with 5 patients showing suprascapular neuropathy according to EMG despite normal muscle status on MRI scans, and the remaining 5 vice versa. Notable atrophy of the infraspinatus was seen in 6 patients and teres minor hypertrophy in 5 patients, all of whom exhibited concurrent infraspinatus atrophy. Postoperatively, cyst disappearance was observed in all cases in both LRCD (24 patients) and LRO (11 patients) groups. Denervation changes in the infraspinatus were resolved in all patients. In patients with infraspinatus atrophy, some improvement was noted. Teres minor hypertrophy persisted in 2 of 4 patients. Improvements were similar in both groups (all P > .05). External rotation power improved postoperatively in both groups (from 39.1 ± 18.6 to 50.6 ± 17.7 N in LRCD, P < .001; from 45.1 ± 16.0 to 54.2 ± 10.7 N in LRO, P = .025).Conclusion:Both LRCD and LRO surgical approaches appear to be effective for paralabral cysts at the spinoglenoid notch. Suprascapular neuropathy can be successfully addressed by both methods. However, conditions with severe infraspinatus atrophy and teres minor hypertrophy warrant further investigation in larger series.

中文翻译：

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盂唇旁囊肿手术治疗后冈下肌去神经支配变化的逆转：一项基于 MRI 的研究


背景： 棘状结肠切迹处的盂旁囊肿是罕见的疾病，可能导致压迫性肩胛上神经病变。鉴于它们的频率较低，尚未建立标准治疗方案。假设/目的： 本研究旨在使用磁共振成像 （MRI） 评估冈下肌的变化，并比较 2 种不同手术方法的结果。据推测，手术干预可以缓解压迫性神经病变，两种手术方法之间的结果相当。研究设计： 队列研究;证据水平， 3.方法： 本回顾性综述包括 43 例因棘状关节盂切迹盂旁囊肿接受关节镜盂唇修复术的患者，囊肿减压 （27 例患者;囊肿减压盂唇修复 [LRCD] 组） 或不进行囊肿减压 （16 例患者;仅盂唇修复 [LRO] 组）。术前 MRI 侧重于评估冈下肌和圆肌小肌的状况。对 36 例患者 （LRCD 21 例，LRO 15 例） 进行肌电图 （EMG） 以评估肩胛上神经功能。对 35 例患者术后 1 年进行术后评估，不包括失访患者。将两组术后 MRI 结果 （LRCD 24 例患者和 LRO 11 例患者） 和功能结局评分（包括外旋力恢复）与术前状态进行比较。结果： 术前 MRI 显示 43 例患者中有 26 例 （60.4%） 出现冈下神经支配改变或萎缩。在 36 例术前接受肌电图检查的患者中，21 例患者 （58.3%;LRCD 13 例，LRO 8 例） 显示肩胛上神经病变的证据。 10 例患者的 EMG 和 MRI 结果之间存在差异，其中 5 例患者尽管 MRI 扫描的肌肉状态正常，但根据 EMG 显示肩胛上神经病变，其余 5 例患者反之亦然。6 例患者出现冈下肌明显萎缩，5 例患者出现圆肌轻度肥大，所有患者均表现出并发冈下肌萎缩。术后，LRCD （24 例患者） 和 LRO （11 例） 组均观察到囊肿消失。所有患者冈下肌的去神经支配变化均得到解决。在冈下肌萎缩患者中，观察到一些改善。4 例患者中有 2 例持续存在圆肌轻度肥大。两组改善相似 （均 P > .05）。两组术后外旋力均有所改善 （LRCD 从 39.1 ± 18.6 ± 50.6 N 至 17.7 N，P < .001;LRO 从 45.1 ± 16.0 至 54.2 ± 10.7 N，P = .025）。结论： LRCD 和 LRO 手术方法似乎对棘状结肠切迹处的盂旁囊肿有效。两种方法都可以成功解决肩胛上神经病变。然而，严重冈下肌萎缩和圆肌轻微肥大的情况需要在更大的系列研究中进行进一步研究。