1.Ganglioneuroma Arising from the Distal Pudendal Nerve
The Nerve 2026;12(1):51-55
Pudendal neuralgia is a painful neuropathy of the pudendal nerve, which contains sensory and motor fibers that innervate the anal, perineal, and genital regions. Secondary pudendal neuralgia may occur after injuries sustained during gynecological or urological surgery; however, cases caused by tumors involving the pudendal nerve are extremely rare. Although schwannomas involving the pudendal nerve have been reported, ganglioneuromas (GN) have not. GN are uncommon tumors composed of mature ganglion cells within a Schwannian stroma and typically arise along the sympathetic plexus or in the adrenal medulla. We present the case of a 41-year-old female patient with perineal neuralgic pain caused by a GN involving the perineal branch of the pudendal nerve for 8 years. The tumor was initially diagnosed as a GN on excisional biopsy but was not completely resected and subsequently recurred. Because of its location below the inferior pubic ramus, complete resection was performed using an anterior approach. Given the potential for recurrence and the risk of malignant transformation to neuroblastoma, complete resection is essential.
3.Pudendal Neuropathy Caused by Deep-Layer Penetration of the Sacrotuberous Ligament with Associated Venous Engorgement: A Surgical Case Report
The Nerve 2026;12(1):32-35
In this report, we describe a rare case of pudendal neuropathy caused by deep-layer penetration of the sacrotuberous ligament (STL), accompanied by perineural venous engorgement, and emphasize its diagnostic and surgical implications. The patient was a 65-year-old man who presented with a 15-year history of left-sided perineal and testicular pain that was markedly exacerbated by sitting and partially relieved by standing or lying down. Pelvic magnetic resonance imaging (MRI) demonstrated asymmetry of the left pudendal nerve, with prominent perineural venous engorgement adjacent to the STL. Conservative treatment failed to provide adequate symptom relief; therefore, transgluteal pudendal nerve decompression was performed. Intraoperatively, the pudendal nerve was found to penetrate the deep layer of the STL and was tightly constricted at the penetration site, with marked venous engorgement. Layer-by-layer release of the deep STL achieved complete neural decompression, followed by gradual collapse of the engorged veins. Postoperatively, the patient experienced immediate and sustained pain relief, with improved tolerance for sitting. Follow-up MRI demonstrated resolution of the venous engorgement and normalization of the perineural soft-tissue signal. In summary, deep-layer penetration of the pudendal nerve through the STL, with associated venous congestion, is rare but clinically significant in pudendal neuropathy. Recognition of this anatomical variant and careful assessment of perineural venous engorgement on MRI may improve diagnostic accuracy and inform layer-by-layer surgical decompression in patients with refractory pudendal neuralgia.
4.Cervical Foraminal Lipoma-Induced Radiculopathy: A Case Report with Surgical Outcomes
Suhyeon KIM ; Byeong Ho OH ; Hyoung Soo BYOUN ; Hong Rye KIM ; Kyung Soo MIN ; Mou Seop LEE ; Joo Yong LEE ; Hyeon Tae KIM ; Jong Beom LEE
The Nerve 2026;12(1):25-31
Cervical foraminal lipoma is a rare cause of cervical radiculopathy. We report the case of a 47-year-old woman who presented with a 1-year history of right arm pain and paresthesia that was refractory to conservative treatment. Magnetic resonance imaging demonstrated a well-defined mass within the right C5-6 neural foramen, causing compression of the exiting C6 nerve root. The patient underwent microsurgical excision via posterior cervical laminoforaminotomy. Intraoperatively, a lipomatous mass compressing the nerve root was identified and completely removed. Histopathological examination confirmed a benign lipoma. Postoperatively, the patient experienced marked symptomatic improvement, with no recurrence of symptoms at a 6-month follow-up. Although it is uncommon, cervical foraminal lipoma should be considered in patients with persistent radiculopathy and atypical imaging findings, and surgical excision can provide favorable clinical outcomes.
5.External Neurolysis for Posterior Interosseous Nerve Syndrome with Refractory Motor Weakness: Clinical Outcomes in a Seven-Patient Case Series
Kihyuk YUN ; Jinseo YANG ; Yong-Jun CHO ; Gwang Yoon CHOI ; Mu Seung PARK
The Nerve 2026;12(1):19-24
Objective:
Posterior interosseous nerve (PIN) syndrome (PINS) is a compressive neuropathy of the deep branch of the radial nerve that primarily presents with motor weakness of finger and thumb extension. Although some patients respond to conservative management, others develop persistent motor deficits requiring surgical decompression. This study aimed to evaluate the clinical outcomes of external neurolysis in patients with PINS presenting with refractory motor weakness.
Methods:
Seven patients with clinically diagnosed PINS who exhibited persistent motor weakness despite conservative treatment and subsequently underwent surgical decompression were retrospectively reviewed. Clinical characteristics, magnetic resonance imaging (MRI) findings, intraoperative compression sites, and postoperative motor recovery were analyzed. Motor strength was evaluated using the Medical Research Council grading system. Preoperative and postoperative motor strength grades were compared using the Wilcoxon signed-rank test.
Results:
The patients presented with progressive weakness of finger extension, resulting in impaired hand opening. MRI demonstrated denervation-related signal changes and atrophy in the affected muscles innervated by the PIN. Surgical exploration revealed compressive structures within the radial tunnel, most commonly at the arcade of Frohse. Significant improvement in motor strength was observed within 2 months postoperatively (thumb extension, p = 0.018; second digit extension, p = 0.011; third to fifth digit extension, p = 0.009). One patient experienced symptom recurrence approximately 6 months after the initial surgery and subsequently underwent revision decompression.
Conclusion
External neurolysis provides meaningful recovery of finger extension in patients with PINS presenting with refractory motor weakness. MRI may support the diagnosis by demonstrating denervation-related morphological changes in the affected muscles. Recurrence of PINS may occur even after initial recovery, highlighting the importance of careful postoperative follow-up.
6.Unknown-Origin Thoracic Spondylitis with Progressive Neurological Deficit Managed by Vertebral Column Resection and Empirical Anti-Tuberculous Therapy: A Case Report
Hyung Joo KIM ; Byeong Ho OH ; Jong Beom LEE
The Nerve 2026;12(1):61-66
Spinal tuberculosis (TB) can be difficult to confirm microbiologically, and delayed treatment may result in irreversible neurological injury. We report the case of a 57-year-old Cambodian man who presented with a 2-month history of upper back pain and right-leg radiculopathy. Thoracic magnetic resonance imaging (MRI) demonstrated destructive spondylitis at T8–9 with epidural and paravertebral abscesses. Despite treatment with broad-spectrum antibiotics and decompression with biopsy at another hospital, serial MRI showed progression of the abscesses and worsening spinal cord compression, followed by bilateral lower-extremity weakness. Repeated acid-fast bacillus staining, mycobacterial culture, TB polymerase chain reaction, and histopathological examination all yielded negative results. A positive QuantiFERON-TB Gold result was considered supportive but not diagnostic evidence because interferon-γ release assays cannot distinguish latent from active TB. Nevertheless, the epidemiological background, MRI findings, chronic inflammatory pathology, and lack of response to non-specific antibiotics supported a clinicoradiological diagnosis of tuberculous spondylitis. Given the patient’s progressive neurological decline, marked destruction of T8 and T9, and overt instability, vertebral column resection was performed at T8–9, followed by anterior reconstruction with a titanium mesh cage and posterior fusion from T5 to T12. Empirical antituberculous chemotherapy was initiated on postoperative day 10. Motor strength improved, inflammatory marker levels decreased, and computed tomography and MRI obtained approximately 3 weeks postoperatively demonstrated stable reconstruction without a drainable fluid collection. This case illustrates that culture-negative spinal TB may require a clinicoradiological diagnosis, early empirical antituberculous therapy, and definitive anterior column reconstruction when progressive instability and neurological compromise are present.
7.Cervical Spinal Melanocytoma: A Case Report and Literature Review
Chan Joo PARK ; Soo Hyun LEE ; Do Heum YOON ; Seong Bae AN ; Inbo HAN ; Seung Hun SHEEN ; Sun-Yoon CHUNG ; Jinhyung HEO ; Hye Jeong CHOI ; Seil SOHN
The Nerve 2026;12(1):56-60
Spinal melanocytoma (SMC) is a rare, slow-growing tumor arising from melanocytes in the spinal cord. We report a patient with a cervical intra- and extradural spinal tumor causing progressive weakness and numbness. On magnetic resonance imaging (MRI), the lesion showed intense homogeneous enhancement, similar to that seen in common neurogenic spinal tumors. After complete resection, pathological examination confirmed melanocytoma. A review of previously reported cases identified 26 reports of this tumor in the cervical spine, most of which were treated with complete surgical resection. Gross total resection is the preferred treatment, although radiation therapy may be considered when residual tumor remains. We report a 25-year-old male patient who presented with progressive weakness and numbness in both the upper and lower extremities for 3 months. MRI showed homogeneous enhancement. The mass compressed the spinal cord at C6–7 and extended through the neural foramen. Based on the MRI findings, spinal schwannoma was suspected preoperatively. Surgical resection was performed with laminectomy, durotomy, and right facetectomy. A dark-colored mass with well-demarcated margins was exposed and removed. Postoperative MRI confirmed complete removal of the mass. The patient recovered well, and his preoperative myelopathic symptoms gradually improved. SMC is a rare benign tumor that may be mistaken for schwannoma. The treatment of choice is gross total resection.
8.Radiological Cut-Off Values for Patient Selection in Intravertebral Cage Augmentation for Osteoporotic Vertebral Fractures: A Preliminary Study
The Nerve 2026;12(1):9-18
Objective:
Transpedicular intravertebral cage augmentation is a less invasive alternative to corpectomy for osteoporotic vertebral fractures (OVFs) with neurological deficits. However, because the intravertebral cage depends on the residual vertebral shell for support, objective criteria for patient selection remain undefined. This study aimed to identify preoperative cutoff values predictive of mechanical failure.
Methods:
Twenty-four patients who underwent transpedicular intravertebral cage insertion with posterior instrumentation for OVFs or Kümmell disease were divided into a mechanical complication (MC) group (n = 9) and a non-MC group (n = 15). Receiver operating characteristic curve analysis was performed to determine preoperative cutoff values.
Results:
The MC group had a lower preoperative index height (13.9 ± 4.2 mm vs. 16.5 ± 2.9 mm; p = 0.043) and a greater pelvic incidence (PI)–lumbar lordosis (LL) mismatch (33.1 ± 17.3° vs. 19.0 ± 11.7°; p = 0.026) than the non-MC group. A preoperative index height of ≤12.7 mm (area under the curve [AUC]= 0.756, specificity = 1.000, p = 0.003) and a PI–LL mismatch of ≥22.9° (AUC = 0.756, odds ratio, 12.0, p = 0.033) were significant predictors of mechanical failure. All patients with an index height of ≤12.7 mm experienced failure. The MC group achieved a greater height restoration ratio (47.4% vs. 22.7%; p = 0.017) but reached a similar postoperative height (~20 mm, p = 0.811), with a strong inverse correlation between preoperative height and restoration ratio (r = −0.804, p < 0.001). Only the MC group showed a significant loss of correction during follow-up (p = 0.020).
Conclusion
A preoperative index height of ≤12.7 mm and a PI–LL mismatch of ≥22.9° may serve as preliminary thresholds indicating the biomechanical limits of intravertebral cage augmentation. In severely collapsed vertebrae, the degree of correction required may exceed what the intravertebral cage can sustain, and these patients may therefore benefit from corpectomy.
9.Endoscopic Fenestration of Suprasellar Arachnoid Cyst: Preoperative Aqueductal Peak Flow Change without Hydrocephalus
Kyoung Chan KIM ; Jun Kyu HWANG
The Nerve 2026;12(1):47-50
An 8-year-old patient presented with mild headaches and was diagnosed with a suprasellar arachnoid cyst (SAC). Patency of the cerebral aqueduct was confirmed using cine magnetic resonance imaging (MRI), and the patient was initially managed with outpatient observation without surgical intervention. However, with worsening headaches and the new onset of bitemporal hemianopsia, a sudden increase in aqueductal peak flow was detected on follow-up cine MRI. Notably, no change in cyst volume or evidence of hydrocephalus was observed on the second MRI. Endoscopic surgery was subsequently performed via the right Kocher’s point, and both the rostral and caudal membranes of the SAC were fenestrated. Following the procedure, the patient’s symptoms improved, and normalization of aqueductal peak flow was confirmed on postoperative cine MRI.
10.A Rare Presentation of Amyloid Angiopathy Involving the Spinal Cord: A Case Report
The Nerve 2026;12(1):41-46
Cerebral amyloid angiopathy (CAA) is a central nervous system disorder characterized by the deposition of amyloid-β peptides within vascular walls, resulting in disruption of normal neural structures. Although CAA may remain asymptomatic, it can also present with a wide spectrum of clinical manifestations, ranging from headache to severe complications such as intracranial hemorrhage or dementia. We report a patient with an intramedullary lesion at the C6-T1 level of the spinal cord that mimicked an intramedullary tumor or inflammatory lesion and presented with arm weakness and pain. An open surgical biopsy followed by histological examination confirmed the diagnosis of spinal cord amyloid angiopathy (SCAA). Postoperative evaluation revealed no evidence of systemic amyloidosis or a familial form of the disease. We describe an exceedingly rare case of SCAA. Solitary SCAA should be considered in the differential diagnosis of progressive intramedullary lesions that resemble spinal cord tumors.

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