A clinicopathological study of low back pain due to middle cluneal nerve entrapment: case series.

PURPOSE: The middle cluneal nerve (MCN) is a pure sensory nerve around the middle buttock. Its entrapment between the iliac crest and the long posterior sacroiliac ligament elicits low back pain (LBP) that can be treated by MCN neurolysis or neurectomy. Because few studies examined the pathology of MCN entrapment (MCN-E) we subjected 7 neurectomized specimens from 6 LBP patients to pathologic study. METHODS: We present 6 consecutive patients (7 sides) with intractable LBP who underwent successful MCN neurectomy. Their symptom duration ranged from 6 to 96 months (average 47.3 months); the follow-up period ranged from 6 to 17 months (average 11.7 months). The surgical outcomes were evaluated using the numerical rating scale (NRS) for LBP and the Roland-Morris Disability Questionnaire (RDQ) score. The resected MCNs underwent neuropathological analysis. RESULTS: Postoperatively, all 6 patients reported immediate LBP amelioration; their NRS and RDQ scores were improved significantly. Pathological study of the 7 resected nerves showed that the myelinated fiber density was decreased in 6 nerves; we observed marked enlargement (n = 5), perineurial thickening and disruption (n = 6), intrafascicular fibrous changes (n = 5), myelinated fibers separated by fibrous cells under the perineurium (n = 4), and Renaut bodies (n = 3). The 7th nerve appeared normal with respect to the density and size of the myelinated fibers, however, the perineurium was slightly thickened. CONCLUSION: We present pathological evidence at the MCN compression site of 7 nerves from 6 patients whose LBP was alleviated by MCN neurectomy, indicating that MCN entrapment can elicit LBP.

Patient satisfaction with cluneal nerve entrapment surgery.

INTRODUCTION: Low back pain (LBP) from superior or middle cluneal nerve entrapment has been addressed surgically. We recorded patient satisfaction with this treatment. METHODS: We included 22 consecutive patients who had undergone surgery for unilateral cluneal nerve entrapment (superior: n = 17, middle: n = 5). The numerical rating scale (NRS) for LBP, the Oswestry Disability Index (ODI) score, and the EuroQOL 5-dimension, 5-level (EQ-5D-5L) scale before and 6 months after the operation were compared. Using these scores, the treatment outcome was compared with the patients' preoperative expectations. RESULTS: LBP was ameliorated in all 22 patients; their NRS, ODI, and EQ-5D-5L were significantly improved after surgery. Surgical satisfaction based on the postoperative NRS scores was recorded as 8.8 ± 1.1 (range 7-10). While the postoperative was significantly better than the expected NRS, the postoperative ODI was significantly higher than expected by the patients (both: p < 0.05). There was a moderate correlation between the postoperative NRS and ODI and postoperative patient satisfaction. CONCLUSION: Patient satisfaction with the surgical result was rated as acceptable.

High-frequency thermal coagulation to treat middle cluneal nerve entrapment neuropathy.

OBJECTIVE: Middle cluneal nerve entrapment (MCN-E) around the sacroiliac joint can elicit low back pain (LBP). Pain control can be obtained with anesthetic nerve blocks; however, when their effectiveness is transient, surgical release may be necessary. We investigated the efficacy of radiofrequency thermocoagulation (RFTC) in patients with MCN-E. METHODS: Between December 2018 and August 2019, 11 consecutive patients (4 men, 7 women; mean age 76.4 years) with intractable medial buttock pain due to MCN-E underwent MCN RFTC. The mean symptom duration was 49.5 months; pre-RFTC local MCN blocks provided pain relief for a mean of 7.7 days. The severity of pain in the medial buttock due to MCN-E was recorded before and 2, 6, 12, and 24 weeks after RFTC on the numerical rating scale (NRS) and the Roland-Morris Disability Questionnaire (RDQ). RESULTS: All patients reported pain alleviation; there were no complications. While there was a significant difference in the pre- and post-RFTC treatment NRS (p < 0.05), the RDQ scores were significantly lower only after 12 weeks. The duration of pain relief was significantly prolonged by RFTC (p < 0.05). Two patients suffered pain relapse 10 weeks post-RFTC; pain alleviation was obtained by re-RFTC performed 2 weeks after pain recurrence. Two other patients relapsed 20 and 21 weeks post-RFTC; their symptoms also disappeared by MCN block administered 24 weeks after they had undergone RFTC. CONCLUSION: RFTC may safely control intractable LBP due to MCN-E.

Quality of life effects of pain from para-lumbar- and lower extremity entrapment syndrome and carpal tunnel syndrome and comparison of the effectiveness of surgery.

INTRODUCTION: We compared the preoperative quality of life (QOL) of patients with carpal tunnel syndrome, lower extremity-, and para-lumbar entrapment syndrome, and the effect of surgery on their QOL. PATIENTS AND METHODS: We prospectively enrolled 66 consecutive patients who underwent surgery for carpal tunnel syndrome (group 1, n = 23), lower extremity entrapment syndrome (group 2, n = 22), and para-lumbar entrapment syndrome (group 3, n = 21). Their pre- and postoperative overall health status was assessed on the Medical Outcomes Study Short-Form 36 Health Survey, v2 (SF-36). RESULTS: Except for the mental component summary, the preoperative score for items rated on the SF-36 was significantly lower in group 3 than in groups 1 and 2 (p < 0.05). In all 66 patients, the scores for bodily pain (BP) and the physical component summary (PCS) were significantly lower (p < 0.05) than the national standard, as was the score for physical functioning (PF) in groups 2 and 3. After surgery, PF of group 2 and PF, BP, and PCS of group 3 improved significantly (p < 0.05). CONCLUSION: The detrimental QOL effects are stronger in patients with para-lumbar- or lower extremity entrapment syndrome than in patients with carpal tunnel syndrome.

[A Case of Guyon's Canal Syndrome Associated with Cubital Tunnel Syndrome].

A 51-year-old man had a 1-year history of numbness on the ulnar side of the 4th finger, the 5th finger, and the ulnar side of the forearm, and weakness of the right hand. The Spurling sign was negative, and cervical radiography and magnetic resonance imaging revealed no abnormality. The Tinel-like signs at the Guyon's canal and cubital tunnel were positive. The diagnosis upon electrophysiological examination was cubital tunnel syndrome and Guyon's canal syndrome, but the possibility of Guyon's canal syndrome was high. Based on the presence of numbness in the forearm, the Tinel-like sign at the cubital tunnel, and the high incidence rate of cubital tunnel syndrome, an operation for cubital tunnel syndrome was performed. After the first operation, the numbness in the forearm was improved, but numbness in the 4th and 5th fingers, and weakness of the right hand remained, and the Tinel-like sign at the Guyon's canal also remained positive. The second operation for Guyon's canal syndrome was performed a month after the first operation for cubital tunnel syndrome. After the second operation, the residual symptoms improved gradually. Guyon's canal syndrome is a rare condition, but it may be considered a causative factor in patients with ulnar neuropathy.

The association between sacroiliac joint-related pain following lumbar spine surgery and spinopelvic parameters: a prospective multicenter study.

PURPOSE: To prospectively calculate the incidence of postoperative sacroiliac joint-related pain (SIJP) and investigate the association between spinopelvic parameters and postoperative SIJP after lumbar spine surgery. METHODS: We prospectively enrolled consecutive patients who underwent lumbar spine surgery. We defined postoperative SIJP as unilateral buttock pain according to fulfillment of the following criteria within 3 months of the surgery: a sacroiliac joint (SIJ) score higher than 4/9 postoperatively; positive response to analgesic periarticular SIJ injection with fluoroscopy; no other complications related to the surgery. The patients were divided into the SIJP group and non-SIJP group. We compared the background information and analyzed the differences in spinopelvic parameters in both groups. Additionally, receiver-operating characteristic curve analyses were performed to evaluate the cutoff values of spinopelvic parameters. RESULTS: Of the 281 patients enrolled, 265 were included and eight developed postoperative SIJP (3.0%). There were no significant differences in the background information between groups. Preoperative and postoperative radiological evaluations revealed that the pelvic incidence (PI) in the SIJP group was significantly higher than that in the non-SIJP group, and there were no significant differences in lumbar lordosis (LL), pelvic tilt, sacral slope, and PI minus LL. For preoperative PI, the area under the curve, cutoff value, sensitivity, and specificity were 0.73739, 59, 62.5%, and 81.9%, respectively. CONCLUSIONS: The incidence of postoperative SIJP after lumbar spine surgery was 3.0%. Higher PI values were associated with a higher risk of postoperative SIJP. These slides can be retrieved under Electronic Supplementary Material.

Gluteus medius muscle decompression for buttock pain: a case-series analysis.

BACKGROUND: The causes of low back and buttock pain are variable. Elsewhere, we presented a surgical technical note addressing the gluteus medius muscle (GMeM) pain that elicited buttock pain treatable by surgical decompression. Here, we report minimum 2-year surgical outcomes of GMeM decompression for intractable buttock pain. METHODS: Between January 2014 and December 2015, we surgically treated 55 consecutive patients with a GMeM pain. Of these, 39 were followed for at least 2 years; they were included in this study. Their average age was 69.2 years; 17 were men and 22 were women. The affected side was unilateral in 24 patients and bilateral in the other 15 (total 54 sites). The mean follow-up period was 40.0 months (range 25-50 months). The severity of pre- and post-treatment pain was recorded on the numerical rating scale (NRS) and the Roland-Morris Disability Questionnaire (RDQ). RESULTS: Of the 39 patients, 35 also presented with leg symptoms. They were exacerbated by walking in all 39 patients and by prolonged sitting in 33 patients; 19 had a past history of lumbar surgery and 4 manifested failed back surgery syndrome. Repeat surgery for wider decompression was performed in 5 patients due to pain recurrence 15.8 months after the first operation. At the last follow-up, the symptoms were significantly improved; the average NRS fell from 7.4 to 2.1 and the RDQ score from 10.5 to 3.3 (p < 0.05). CONCLUSIONS: When diagnostic criteria are met, GMeM decompression under local anesthesia is a useful treatment for intractable buttock pain.

Low back pain due to superior cluneal nerve entrapment: A clinicopathologic study.

INTRODUCTION: We studied the clinical and nerve pathologic features in 6 patients whose low back pain (LBP) was relieved by superior cluneal nerve (SCN) neurectomy to determine whether nerve compression was the mechanism underlying this type of LBP. METHODS: All 6 patients (7 nerves) underwent SCN neurectomy for intractable LBP. Their clinical outcomes and the pathologic features of 7 nerves were reviewed. RESULTS: All patients reported LBP relief immediately after SCN neurectomy. Pathologic study of the 7 resected nerves showed marked enlargement, decreased myelinated fiber density, an increase in thinly myelinated fibers (n = 2), perineurial thickening (n = 5), subperineurial edema (n = 4), and Renaut bodies (n = 4). At the distal end of 1 enlarged nerve, we observed a moderate reduction in the density and marked reduction in the number of large myelinated fibers. DISCUSSION: The pathologic findings and effectiveness of neurectomy suggest that, in our patients, SCN neuropathy likely elicited LBP via nerve compression. Muscle Nerve 57: 777-783, 2018.

[Chronic Low Back Pain Associated with Gluteus Medius Muscle:A Case Report].

The clinical features and etiology of low back pain(LBP)and buttock pain(BuP)has been poorly understood. We report a case of long-term BuP that was successfully treated with gluteus medius muscle(GMeM)decompression under local anesthesia. A 71-year-old man was referred to our hospital because of long-term BuP and claudication. Left BuP that radiated to the left thigh was observed. The pain was mostly triggered by palpation at the middle of the iliac crest and greater trochanter. Lumbar and pelvic radiograms showed no significant lesions. Lumbar magnetic resonance imaging revealed a mild lumbar spinal canal stenosis at the L4/L5 segment. Based on the evidence of a trigger point and pain relieved after GMeM block injection, we made a diagnosis of GMeM pain. Although several GMeM block injections relieved his pain, the analgesic effect was transient and the claudication remained. Then, we decided to perform GMeM decompression. We made a 5-cm-long skin incision across the trigger point on the buttock. After confirming a wide exposure of the gluteal aponeurosis over the GMeM, we cut and opened it for sufficient GMeM decompression, and the GMeM expansion was confirmed. After surgery, his symptoms immediately improved. No evidence of recurrence was observed 6 months after his treatment. For the treatment of LBP and BuP, GMeM pain would be considered a causative factor. We report that it can be treated with a less invasive surgical technique, which would contribute to good clinical outcome.

[Magnetic Resonance Imaging Conditions for Imaging of the Tarsal Tunnel].

BACKGROUND: Tarsal tunnel syndrome(TTS)is an entrapment neuropathy of the posterior tibial nerve within the tarsal tunnel below the medial malleolus. An accurate diagnosis is difficult, and TTS is usually diagnosed from clinical symptoms due to the lack of accurate diagnostic tools. We aimed to standardize the diagnosis of TTS using MRI, and report the MRI conditions for clear visualization of the tarsal tunnel. METHODS: We investigated which sequences and MRI conditions would be appropriate for the imaging of the tarsal tunnel in a healthy volunteer. As in routine brain MRI, the imaging time was within 15 minutes. We also performed an MRI study of the tarsal tunnel in two patients with TTS. RESULTS: Axial images obtained by fat-suppression 3-dimensional T2*-weighted imaging(3D-T2*WI)are the most useful for visualization of the tarsal tunnel. The axial images obtained by T2-weighted imaging(T2WI)and T1-weighted imaging(T1WI)were also useful for visualization of the area around the flexor retinaculum. The appropriate slice thickness was determined to be 1.5 mm, based on the resolution and photographic time. The flip angle, necessary for tissue resolution, was set at 15° because it provided the clearest image and highest contrast between different tissues. The total photographic time was within 14 minutes, and it is acceptable for routine MRI studies of TTS. In the two cases of TTS included in this study, the tarsal tunnel was clearly visible. CONCLUSIONS: For diagnosis of TTS using MRI, axial images obtained by fat-suppression 3D-T2*WI, 2-dimensional(2D)-T2WI, and 2D-T1WI are recommended. A coronal image obtained by reconstruction of fat-suppression 3D-T2*WI might be useful for anatomical understanding. In future studies, we plan to evaluate patients with TTS using the above protocol.

[Treatment Results of Low Back and Leg Pain Considering Para-Lumbar Spine Disease and Peripheral Nerve Neuropathy].

INTRODUCTION: Here we report our treatment results of low back and leg pain(LBLP)considering para-lumbar spine disease(PLSD)and peripheral nerve neuropathy(PNN). MATERIALS AND METHODS: We enrolled 103 patients who were admitted to our institute for LBLP treatment between January and December in 2014. For the treatment, we preferentially performed intensive block therapy for PLSD. RESULT: Among 103 patients, 89 patients had PLSD. In 85 patients, we performed intensive block therapy and 82 patients experienced short-term improvement of symptoms. In 35 of these 82 patients, lumbar spine and/or PNN surgical treatment was required as the effect of block therapy was transient. Intensive block therapy was effective in 47 of 103 patients(45.6%), and the remaining patients required surgical treatment(PLSD and/or PNN:31 cases, lumbar spine:13 cases, both:8 cases). CONCLUSION: Among 103 patients with LBLP, intensive block therapy for PLSD and PNN was useful for short-term symptom improvement in 82 patients(79.6%), and for long-term symptom improvement in 47 patients(45.6%)as evaluated at the final follow-up. Surgical treatment of PLSD and/or PNN was required in 39 patients(37.9%). These results suggested that treatment of PLSD and PNN might yield good results for patients with LBLP.

Dynamic factors involved in common peroneal nerve entrapment neuropathy.

BACKGROUND: Common peroneal nerve (CPN) entrapment neuropathy (CPNEN) is the most common peripheral neuropathy of the lower extremities. The pathological mechanisms underlying CPNEN remain unclear. We sought to identify dynamic factors involved in CPNEN by directly measuring the CPN pressure during stepwise CPNEN surgery. METHODS: We enrolled seven patients whose CPNEN improved significantly after CPN neurolysis. All suffered intermittent claudication, and the repetitive plantar flexion test, used as a CPNEN provocation test, was positive. During decompression surgery we directly measured the CPN pressure during several decompression steps. RESULTS: Before CPN decompression, plantar flexion elicited a statistically significant increase in the CPN pressure (from 1.8 to 37.3, p < 0.05), as did plantar extension (from 1.8 to 23.1, p < 0.05). The CPN pressure gradually decreased during step-by-step surgery; it was lowest after resection of the peroneus longus muscle (PLM) fascia. CONCLUSIONS: Dynamic factors affect idiopathic CPNEN. The CPN pressure decreased at each surgical decompression step, and removal of the PLM fascia resulted in adequate decompression of the CPN. Our findings shed light on the etiology of idiopathic CPNEN and recommend adequate CPNEN decompression procedures.

[A Case of Meralgia Paresthetica Treated with Neurolysis].

A 60-year-old woman presented with a 1-year history of pain and numbness in the left anterolateral thigh. The symptoms aggravated on walking and standing. Her visual analogue scale(VAS)score was 7.1/10. Tinel's like sign was positive over the lateral femoral cutaneous nerve(LFCN), in the inguinal ligament region. LFCN block at the trigger point, in the inguinal ligament, resulted in relief of the symptoms and we diagnosed meralgia paresthetica(MP), which is the entrapment neuropathy of the LFCN. Initially, we performed observation therapy with oral medication and LFCN blocks. However, these treatments failed to relieve the symptoms. Therefore, we performed neurolysis with a microscope under local anesthesia. The symptoms improved immediately after surgery and her VAS score of thigh symptom improved from 7.1 to 1.9 after 3 months. Conservative and surgical treatment for MP generally yield good outcome and we should pay attention to the MP as a differential diagnosis for thigh numbness and pain.

Decompression of the gluteus medius muscle as a new treatment for buttock pain: technical note.

PURPOSE: The clinical features and etiology of low back pain and buttock pain remain poorly understood. We report ten patients with buttock pain who underwent gluteus medius muscle (GMeM) decompression under local anesthesia. METHODS: Between December 2012 and November 2013 we surgically treated ten patients (four men, six women; mean age 65.1 years) for buttock pain. The affected side was unilateral in seven and bilateral in three patients (total sites, n = 13). The interval from symptom onset to treatment averaged 174 months; the mean postoperative follow-up period was 24 months. Decompression of the tight gluteal aponeurosis over the GMeM was performed under local anesthesia. Assessment of the clinical outcomes was on the numeric rating scale (NRS) for low back pain (LBP), the Japanese Orthopedic Association (JOA) score, and the Roland-Morris Disability Questionnaire (RDQ) score before and at the latest follow-up after treatment. RESULTS: There were no intraoperative surgery-related complications. The buttock pain of all patients was improved after surgery; their NRS decreased from 7.0 to 0.8 and JOA and RMDQ scores indicated significant improvement (p < 0.05). CONCLUSION: In patients with buttock pain, pain around the GMeM should be considered as a causative factor. Less invasive surgery with cutting and opening of the tight gluteal aponeurosis over the GMeM under local anesthesia yielded excellent clinical outcomes.

Surgical treatment for posttraumatic hemorrhage inside a filum terminale myxopapillary ependymoma: a case report and literature review.

PURPOSE: Symptoms of cauda equina syndrome due to ependymoma in the conus medullaris or filum terminale develop slowly. However, hemorrhagic change inside spinal tumors can induce acute neurologic decline. Here, we report a case of posttraumatic hemorrhage inside a filum terminale myxopapillary ependymoma presenting as acute neurologic decline, which had a positive prognosis after surgical resection. METHODS: A 28-year-old man presented with buttock pain, sensory disturbance, and motor weakness of bilateral lower extremities after falling on ice during smelt fishing. Magnetic resonance imaging demonstrated a mixed-intensity hemorrhagic intradural mass extending from L1 to L2. RESULTS: The patient underwent emergent surgical decompression and resection. Pathologic examination revealed a myxopapillary ependymoma with intratumoral hemorrhage. After surgery, the patient demonstrated gradual improvement in neurologic deficits and no tumor recurrence. CONCLUSIONS: This is the first case of a filum terminale myxopapillary ependymoma with an acute neurologic decline after injury. Early diagnosis and treatment are associated with favorable outcomes.

[Prospective Study of the Causes of Limb Numbness in Patients with Diabetes].

PURPOSE: Many patients with diabetes mellitus (DM) experience numbness in the extremities. This DM neuropathy may be complicated by peripheral entrapment neuropathy. We prospectively investigated the cause(s) of limb numbness in DM patients. MATERIALS AND METHODS: We enrolled 23 patients with uni- or bilateral limb numbness who were treated in our DM clinic. They were 10 men and 13 women; their average age was 63 years. The average duration of their neurological symptoms was 28.3 months. RESULTS: Numbness was located in the upper limb in 7 patients, the lower limb in 11, and both the upper and lower limbs in 5. Among the 12 patients with upper-limb numbness, 9 manifested carpal tunnel syndrome and one each cervical OPLL or cervical spondylosis. Of the 16 cases of lower limb numbness, 10 were attributable to tarsal tunnel syndrome, 7 to lumbar spinal disease, 3 to restless leg syndrome, 2 to piriformis syndrome, and 1 to peroneal nerve entrapment neuropathy. CONCLUSIONS: In 21 of the 23 patients with uni- or bilateral limb numbness, the cause was attributable to several kinds of etiology such as entrapment neuropathy. Consequently, other treatable peripheral nerve disorders, e.g. tarsal tunnel syndrome, must be considered when diagnosing DM patients with limb numbness. Our findings suggest that therapeutic intervention to address such diseases will affect the quality of life of DM patients with limb numbness.

[Non-Specific Back Pain due to Superior Cluneal Nerve Entrapment Neuropathy Treated with Neurolysis: A Case Report].

A 43-year-old man with a 10-year history of low back pain (LBP) had been conservatively treated elsewhere with medications for non-specific back pain. He presented to our institute with LBP and difficulty in standing up, sitting down, and sitting for prolonged periods. His Numerical Rating Scale score, due to LBP, was 8 out of 10. He had numbness on the lateral aspect of his left thigh. A lumbar radiography and magnetic resonance imaging studies revealed mild degenerative changes and mild canal stenosis in the lumbar spine. Palpation over the left posterior superior iliac crest, 8 cm from the midline over the iliac crest, revealed severe tenderness. A superior cluneal nerve(SCN)block performed at the trigger point in both the buttocks resulted in complete pain abatement and disappearance of the radiating pain. Therefore, we diagnosed SCN entrapment neuropathy(SCNE). However, the pain reappeared a few days later and subsequent treatments failed to relieve it; therefore, we decided to perform surgery. The SCN penetrates the thoracolumbar fascia through an orifice just before crossing over the iliac crest. We opened the orifice with microscissors in a distal to rostral direction along the SCN and released the entrapped nerve. After surgery, the symptoms were relieved and the patient experienced no recurrence in the last 4 years after the treatment. SCNE should be considered as a causative factor of LBP, and its treatment using minimally invasive surgery yields excellent clinical outcome.

[Clinical feathers and treatment of peroneal nerve entrapment neuropathy].

OBJECTIVE: Peroneal nerve entrapment neuropathy (PEN) is generally known as a drop foot with sensory disturbance. However, some patients experience numbness and pain in the affected area without severe paresis due to PEN. We report the clinical features and our surgical results of PEN cases. METHODS: We encountered 17 cases of PEN. The patients were 7 females and 10 males and their ages ranged from 30 to 78 years(average 56.1 years). In these cases, conservative therapy was unsuccessful;therefore, we performed surgical treatment for PEN. RESULTS: Among the 17 cases, 4 were of bilateral and 13 were of unilateral PEN. There was no severe paresis, as in drop foot;however, mild paresis (4/5, manual muscle test, MMT) was noted in 15 cases. In all cases, intermittent claudication presented, which ranged from 10 to 800 m (average 150 m). In 13 cases, radiological abnormality of the lumbar region was noted and 8 cases had a history of lumbar surgery (they had failed back surgery syndrome). In all the cases, we performed neurolysis of the peroneal nerve under local anesthesia;there was no surgical complication. After the surgery, symptoms improved, and the numerical rating of the lower limb improved from 8.6/10 to 0.8/10. Intermittent claudication also improved in all of the cases. CONCLUSIONS: We successfully treated 17 cases of PEN, which had lower limb pain without severe paresis, as in drop foot. Our results indicate that PEN should be recognized as a cause of intermittent claudication. Neurolysis for PEN under local anesthesia is less invasive and is useful for the treatment of lower limb pain.

Ganglia-Induced Tarsal Tunnel Syndrome.

BACKGROUND: Tarsal tunnel syndrome (TTS) is a common entrapment neuropathy that is sometimes elicited by ganglia in the tarsal tunnel. METHODS: Between August 2020 and July 2022, we operated on 117 sides with TTS. This retrospective study examined data from 8 consecutive patients (8 sides: 5 men, 3 women; average age 67.8 years) with an extraneural ganglion in the tarsal tunnel. We investigated the clinical characteristics and surgical outcomes for these patients. RESULTS: The mass was palpable through the skin in 1 patient, detected intraoperatively in 1 patient, and visualized on MRI scanning in the other 6 patients. Symptoms involved the medial plantar nerve area (n = 5), lateral plantar nerve area (n = 1), and medial and lateral plantar nerve areas (n = 2). The interval between symptom onset and surgery ranged from 4 to 168 months. Adhesion between large (≥20 mm) ganglia and surrounding tissue and nerves was observed intraoperatively in 4 patients. Of the 8 patients, 7 underwent total ganglion resection. There were no surgery-related complications. On their last postoperative visit, 3 patients with a duration of symptoms not exceeding 10 months reported favorable outcomes. CONCLUSIONS: Because ganglia eliciting TTS are often undetectable by skin palpation, imaging studies may be necessary. Early surgical intervention appears to yield favorable outcomes.

Paralysis Immediately after Surgical Decompression for Common Peroneal Nerve Entrapment.

OBJECTIVE: Common peroneal nerve (C-PN) entrapment neuropathy is the most common peripheral nerve neuropathy of the legs. C-PN decompression surgery is less invasive but may result in neurological complications. We report a rare case of nerve paralysis immediately after C-PN decompression surgery. CASE REPORT: An 85-year-old man presented with leg numbness and pain. An electrophysical study revealed C-PN entrapment in the affected area and he underwent surgical decompression. Immediately after the procedure he complained of slight paralysis without pain (manual muscle test: 3/5), which gradually worsened and was complete at 60 min after surgery. We re-opened the skin incision 3 hours after the first operation and found that a subcutaneous suture had been applied to the connective tissue near the C-PN, resulting in marked compression of the nerve. After release of the suture his paralysis improved immediately. We confirmed that there was no other nerve compression and finished the operation. His paralysis disappeared completely. CONCLUSION: Peripheral nerve surgery, including C-PN decompression surgery, is less invasive, and the risk of complications is low. However, because the C-PN is located in the shallow layer under the skin, an excessively deep suture in the subcutaneous layer may compress the nerve and elicit nerve palsy. Therefore, careful postoperative follow-up is necessary because early decompression leads to good surgical results.