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Predictive factors of Postoperative Neurological Deficit in the Surgical Management of Upper Extremity Schwannomas
Tsai Shih Chen, MD
1; Jung-Hsien Hsieh, MD, PHD
2(1)National Taiwan University Hospital, Taipei, 10002, Taiwan, (2)Plastic surgery, National Taiwan University Hospital and College of Medicine, Taipei, Taiwan
Introduction:Schwannomas are the most common benign peripheral nerve tumors, typically well-encapsulated. However, the incidence of postoperative neurological complications varies, and predictive factors remain unclear. While enucleation is the standard treatment
(Fig 1.), no consensus exists on the factors predicting adverse neurological outcomes, particularly in the upper extremities. The objective of this study is to identify and clarify the predictive factors associated with postoperative neurological deficits after surgical treatment of schwannomas affecting the upper limb nerves.
Materials and Methods:This is a single-center, retrospective study of patients treated between 2012 and 2022. All procedures were performed by a single surgeon specializing in upper limb nerve surgery. A total of 47 patients with schwannomas involving the major nerves of the upper extremities were included in the analysis. Schwannomas originating from terminal branches within the muscle or skin were excluded. Data on preoperative clinical features and postoperative neurological complications were collected, and predictive factors for neurological complications were assessed through statistical analysis.
Mixed nerves were defined as those containing motor fascicles, including the brachial plexus, trunks of the median, ulnar, radial, and musculocutaneous nerves, as well as the posterior interosseous nerves.
Sensory nerves were defined as those composed exclusively of sensory fascicles, such as digital nerves, the medial brachial cutaneous nerve, and the superficial branch of the radial nerve.
Results:Postoperative neurological deficits were observed in 20 lesions (42.3%), including 16 cases (34.0%) of sensory disturbance and 9 cases (19.1%) of motor weakness. Preoperatively, sensory deficits were present in 19 patients (40.4%) and motor deficits in 3 patients (6.4%). McNemar's test
(Table 1.) demonstrated significant postoperative improvement in pain (p = 0.0016) and tenderness (p < 0.001), while the motor deficits increased significantly (p = 0.0339). Logistic regression analysis indicated that involvement of mixed nerve was associated with an increased risk of total neurological deficits (
Table 2. OR: 58.57, p = 0.030), and fascicular resection was associated with a higher risk of postoperative motor deficits (
Table 3. OR: 9.0, p = 0.030).
Conclusions:In upper extremity schwannomas, tumors involving mixed nerves are associated with a significantly increased risk of postoperative neurological deficits. Intraoperative fascicular resection is a key risk factor for postoperative motor weakness. These findings highlight the importance of preoperative risk stratification and careful intraoperative decision-making. Surgeons should exercise caution when planning excision of tumors arising from motor-dominant nerves and consider nerve-sparing techniques whenever feasible to minimize functional morbidity.
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