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.

Middle cluneal nerve entrapment sites in the surgical field.

INTRODUCTION: Middle cluneal nerve (MCN) entrapment around the sacroiliac joint elicits low back pain (LBP). For surgical decompression to be successful, the course of the MCN must be known. We retrospectively studied the MCN course in 15 patients who had undergone MCN neurolysis. METHODS: Enrolled in this retrospective study were 15 patients (18 sides). We inspected their surgical records and videos to determine the course of the entrapped MCN. The area between the posterior superior- and the posterior inferior iliac spine was divided into areas A-D from the rostral side. The MCN transit points were identified at the midline and the lateral edge connecting the posterior superior- and posterior inferior iliac spine. Before and 6 months after surgery, the patients recorded the degree of LBP on the numerical rating scale and the Roland-Morris Disability Questionnaire. RESULTS: We decompressed 24 MCNs. The mean number was 1.3 nerves per patient (range 1-2). The MCN course was oblique in the cranio-caudal direction; the nerve tended to be observed in areas C and D. In six patients (40%), we detected two MCN branches, they were in the same area and adjacent. Postoperatively, LBP was improved significantly in all patients. CONCLUSION: Between the posterior superior- and the posterior inferior iliac spine, the MCN ran obliquely in the cranio-caudal direction; it was prominent in areas on the caudal side. In six (40%) patients, we decompressed two adjacent MCNs. Our findings are useful for MCN decompression surgery.

Identification and decompression of superior cluneal nerve implicated in low back pain.

INTRODUCTION: Low back pain (LBP) can be attributable to entrapment of the superior cluneal nerve (SCN) around the iliac crest. Surgical decompression is a useful treatment; however, finding all entrapped SCNs involved in patients with LBP can be difficult. We performed a retrospective study to help identify entrapped SCNs in the narrow surgical field. METHODS: We enrolled 20 LBP patient (22 sides) with SCN entrapment. They were 9 males and 11 females; their mean age was 72.5 years. We developed a 3-step procedure for successful SCN decompression surgery. In step 1, the thoracolumbar fascia is exposed and the SCN penetrating the fascia is released. In step 2, the fascia is opened and the SCN is released. In step 3, the fascia above the iliac crest is opened and the SCN is released. RESULTS: We successfully released 66 nerves; the average was 3.0 ± 0.8 (1-4) per patient. Step 1 detected 18 nerves (27.3%), step 2 identified 35 (53.0%), and in step 3, 13 (19.7%) were recognized. By tracing the thin nerves branching off the SCN, we found 7 nerves (10.6%). We performed 22 operations; step 1 identified 16 SCNs (72.7%), step 2 identified 21 (95.5%), and step 3 found 12 nerves (54.5%). CONCLUSIONS: The SCN is most readily identified upon opening of the thoracolumbar fascia. To identify as many SCN branches as possible, our 3-step method may be useful.

Long-term outcome after surgery for middle cluneal nerve entrapment neuropathy.

PURPOSE: Entrapment of the middle cluneal nerve (MCN-E) can elicit low back pain (LBP). Patients whose LBP responds only transiently to the analgesic effects of MCN blockage may be candidates for surgery. This study addresses its long-term efficacy. METHODS: We initially subjected 34 MCN-E patients (48 sides) to surgical release. Of these, 4 were excluded from this study because their follow-up was shorter than 24 months. The mean age of the 30 included patients was 71.5 years; the mean postoperative follow-up period was 40.4 months. Clinical outcomes were assessed on the Numerical Rating Scale (NRS) for LBP and the Roland Morris Disability Questionnaire (RDQ) before surgery and at the latest follow-up visit. RESULTS: The 30 patients (44 sides) reported severe LBP, leg symptoms were elicited by 32 sides. A mean of 1.4 MCN branches were surgically released, 32 sides were addressed by neurolysis, 7 by neurectomy, and 5 underwent both procedures due to the presence of 2 nerve branches. There were no complications. In the course of a mean follow-up of 26.3 months, MCN-E elicited recurrent symptoms on 6 sides; all had undergone neurolysis or neurectomy and a second operation improved the symptoms. All patients showed significant improvement at the last follow-up visit. Postoperatively both their NRS for LBP and their RDQ scores were improved (pre- vs. postoperative scores, p < 0.05). CONCLUSIONS: While surgical release of MCN-E is expected to yield long-term symptom relief, on 6 of 32 sides (18.8%) treated by neurolysis the patients reported pain recurrence. Whether neurectomy effectively prevents the recurrence of MCN-E in the long term requires further study.

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.

Clinical features of middle cluneal nerve entrapment neuropathy.

BACKGROUND: Entrapment of the middle cluneal nerve (MCN), a peripheral nerve in the buttock, can elicit low back pain (LBP). We examined the epidemiology, clinical course, and treatment of MCN entrapment (MCN-EN). METHODS: Among 383 LBP patients who visited our institute, 105 were admitted for intractable LBP. They were 42 men and 63 women; their average age was 64 years. Based on clinical symptoms, palpation, and the effects of MCN block, we suspected MCN-EN in these 105 patients, 50 of whom are our study subjects. Their treatment outcomes were assessed at the time of discharge and at follow-up visits. RESULTS: MCN-EN was diagnosed in 50 of the 383 patients (13.1%) and they were hospitalized. In 43 (11.2%), MCN-EN was associated with other diseases (superior cluneal nerve entrapment, n = 21, sacroiliac joint pain, n = 9, other, n = 13). At the time of discharge, the symptoms of patients with LBP due to MCN-EN were significantly improved by repeat MCN blocks. In 7 of the 383 patients (1.8%), LBP was improved by only MCN blocks; 5 of them had reported leg symptoms in the dorsal part of the thigh. After discharge, 22 of the 50 hospitalized patients required no additional treatments after 2-5 blocks; 19 required only conservative treatment, and 9 underwent microsurgical release of the MCN. CONCLUSIONS: We confirmed MCN-EN in 50 of 105 patients admitted for intractable LBP. Repeat MCN blocks were effective in 22 patients; 19 required additional conservative treatment, and 9 underwent surgery. Buttock pain radiating to the posterior thigh was an MCN-EN symptom that has been diagnosed as pseudo-sciatica. Before subjecting patients with intractable LBP to surgery, the presence of MCN-EN must be ruled out.

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.

Middle cluneal nerve entrapment mimics sacroiliac joint pain.

BACKGROUND: Sacroiliac joint (SIJ)-related pain is associated with low back- and buttock pain and the SIJ score is diagnostically useful because it helps to differentiate between SIJ-related pain and pain due to other factors such as lumbar disc herniation and lumbar spinal canal stenosis. Middle cluneal nerve (MCN) entrapment (MCN-E) can produce pain involving the lower back and buttocks. Therefore, the origin of the pain must be identified. We successfully treated patients with a high SIJ score whose pain was attributable to MCN-E. METHODS: Between August 2016 and June 2017, we treated 40 patients with non-specific low back pain. Among them, 18 (45%) presented with a positive SIJ score. Although SIJ treatment was unsuccessful in 4 of these patients, they responded to MCN-E treatment. RESULTS: All 4 patients reported tenderness at the site of the sacrotuberous ligament (STL); 3 were positive for the one-finger test and experienced pain while sitting in a chair. The effect of SIJ block was inadequate in the 4 patients. As they reported severe pain at the trigger point in the area of the MCN, we performed MCN blockage. It resulted in pain control. However, in 1 patient, the effect of MCN block was transient and required MCN neurolysis. At the last visit, our patients' symptoms were significantly improved; their average numerical rating scale score fell from 8.3 to 1.0, their Roland-Morris Disability Questionnaire score fell from 12.8 to 0.3, and their average Japanese Orthopaedic Association score rose from 12.5 to 19.5. CONCLUSIONS: In patients with suspected SIJ-related pain, the presence of MCN-E must be considered when the effect of SIJ block is unsatisfactory.

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.

A Case of Juvenile Stroke due to Carotid Artery Dissection from an Elongated Styloid Process-Revisiting Conservative Management.

Carotid artery dissection is a significant etiology of juvenile stroke. Blunt trauma from an elongated styloid process can rarely cause carotid artery dissection, which is one of well-known clinical presentations of Eagle's syndrome as known as stylocarotid syndrome. Growing number of publications contributed improved awareness and diagnostic modalities for this clinical entity, thus the carotid artery dissection from an elongated styloid process is often diagnosed appropriately. The management of carotid artery dissection in stylocarotid syndrome tends to be nonconservative (ie, removal of the process or carotid stenting) presumably due to a publication bias prone to surgical intervention. However, the compression of elongated styloid process to carotid artery is usually difficult or even dangerous to directly prove. Furthermore, stent fracture with subsequent stent and carotid artery occlusion has been reported as a complication of the treatment. Here, we report a male presenting with acute embolic stroke due to carotid artery dissection with the ipsilateral elongated styloid process who has been managed conservatively for more than 1.5 years without any sequelae. We will discuss the management strategy and emphasize the importance of patient education of daily life, since the surgical intervention seems not always necessary in this clinical setting.

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.

Low back pain due to middle cluneal nerve entrapment neuropathy.

PURPOSE: The etiology of low back pain (LBP) is complicated and the diagnosis can be difficult. Superior cluneal nerve entrapment neuropathy (SCN-EN) is a known cause of LBP, although the middle cluneal nerve (MCN) can be implicated in the elicitation of LBP. METHODS: A 76-year-old woman with a 4-year history of severe LBP was admitted to our department in a wheelchair. She complained of bilateral LBP that was exacerbated by lumbar movement. Her pain was severe on the right side and she also suffered right leg pain and numbness. Based on palpation and nerve blocking findings we diagnosed SCN-EN and MCN entrapment neuropathy (MCN-EN). RESULTS: Her symptoms improved with repeated SCN and MCN blocking; the MCN block was the more effective and her symptoms improved. As her right-side pain around the MCN -EN with severe trigger pain recurred we performed microscopic right MCN neurolysis under local anesthesia. This led to dramatic improvement of her LBP and leg pain and the numbness improved. At the last follow-up, 7 months after surgery, she did not require pain medication. CONCLUSIONS: The MCN consists of sensory branches from the dorsal rami of S1-S4. It sandwiches the sacral ligament between the posterior superior and inferior iliac spine as it courses over the iliac crest. Its entrapment at this hard orifice can lead to severe LBP with leg symptoms. An MCN block effect is diagnostically useful. Less invasive MCN neurolysis under local anesthesia is effective in patients who fail to respond to observation therapy.

[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.

[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.

[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.

A Diagnostic Scoring System for Sacroiliac Joint Pain Originating from the Posterior Ligament.

Objective: Sacroiliac joint (SIJ) pain originating from the posterior ligament manifests in not only the buttocks but also the groin and lower extremities and thus may be difficult to discern from pain secondary to other lumbar disorders. We aimed to develop a simple clinical diagnostic tool to help physicians distinguish between patients with SIJ pain originating from the posterior ligament and those with lumbar disc herniation (LDH) or lumbar spinal canal stenosis (LSS). Design: Prospective case-control study. Patients and Methods: We evaluated 62 patients with SIJ pain originating from the posterior ligament and 59 patients with LDH and LSS. Pain areas, pain increasing positions, provocation test, and tenderness points were investigated. A scoring system based on multivariate logistic regression equations using the investigated items was developed. Results: Two pain areas (the posterosuperior iliac spine (PSIS) detected by the one-finger test and groin), pain while sitting on a chair, provocation test, and two tenderness points (PSIS and the sacrotuberous ligament) had high odds ratios (range, 25.87­1.40) and were used as factors in the scoring system. An integer score derived from the regression coefficient and clinical experience was assigned to each identified risk factor. The sum of the risk score for each patient ranged from 0­9. This scoring system had a sensitivity of 90.3% and a specificity of 86.4% for a positivity cutoff point of 4. Conclusion: The scoring system can help distinguish between patients with SIJ pain originating from the posterior ligament and those with LDH and LSS.

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.