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.

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.

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.

[Microneurosurgical Treatment for Refractory Entrapment Neuropathy of Suprascapular Nerve:A Case Report].

Suprascapular nerve entrapment is rarely treated by neurosurgeons in Japan. However, it is often observed in post-stroke patients and in cases of accessory nerve injury as a complication of posterior fossa craniotomy. We report a case of suprascapular nerve entrapment due to superior transverse scapular ligament, which was successfully diagnosed and surgically treated. The patient was a 66-year-old female who used be a janitor. She complained of dysesthesia around the shoulder. The diagnosis was made based on the characteristic neurological findings including pain around the scapula, supraspinatus muscle weakness, and favorable but temporary response to suprascapular nerve block. After undergoing conservative management for one and a half year, she decided to undergo the nerve decompression surgery. The surgical treatment was performed under microscope with neuromonitoring. Following surgery, the painful area was dramatically reduced. We believe that suprascapular nerve disorders can be treated with careful neurological evaluation by neurosurgeons.

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.

[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.

Do characteristics of dissection differ between the posterior inferior cerebellar artery and the vertebral artery?

OBJECTIVE: The purpose of this study was to clarify the features of posterior inferior cerebellar artery (PICA) dissection. MATERIALS AND METHODS: We prospectively registered 93 consecutive patients and 108 arteries with confirmed diagnoses of dissection in the vertebral artery (VA) or PICA between February 2007 and January 2014. Patients were diagnosed with arterial dissection when they had both acute symptoms and radiological characteristics in magnetic resonance imaging or digital subtraction angiography. Patients were divided into 2 groups depending on whether the site of dissection was VA (VA group) or PICA (PICA group). We compared the clinical and radiological characteristics and clinical outcomes of PICA versus VA dissection. RESULTS: Of the 93 patients included in this study, 83 were in the VA group, and 10 had arterial dissection in the PICA. Patients with PICA dissection more frequently suffered from SAH (P < .001), whereas nonstroke symptom was often the initial symptom in the VA group. Pearl sign was seen most frequently at the dissection site of PICA. Surgical or endovascular treatment was performed in 9 of 10 PICA dissections, whereas more than half of the VA dissections were treated conservatively (P < .001). SAH was significantly more severe in the patients with PICA dissection compared with those in the VA group (P = .049). CONCLUSION: Patients with PICA dissection suffered from subarachnoid hemorrhage more frequently than those with VA dissection. PICA dissection was treated with surgical intervention, whereas VA dissection was treated conservatively.

Paralumbar Spine Disease as a Cause of Low Back Pain in Older Adults.

Introduction Low back pain (LBP) is a major contributor to decreases in the ability to perform activities of daily living (ADL) in older adults. Paralumbar spine disease (PLSD) is a common cause of LBP. We aimed to investigate the causes of LBP, including PLSD, among older adults. Methods Among 744 consecutive patients with LBP, 75 patients (10.1%) aged >80 years (25 males and 50 females) were included. The average patient age was 83.9 years. All patients were evaluated using lumbar magnetic resonance imaging (MRI) and radiography to diagnose the causes of LBP. PLSD was diagnosed based on clinical symptoms, palpation, and the effects of the block. Results Eleven patients (11/75, 14.7%) had acute osteoporotic vertebral fractures. Twenty-eight of the remaining 64 patients exhibited decreased LBP with oral medication, and six (6/75, 8.0%) exhibited lumbar spinal canal stenosis on MRI. PLSD was suspected in 19 of the remaining 30 cases based on clinical symptoms and palpation. Blocks were effective in 16 patients with PLSD, which involved superior cluneal nerve entrapment (SCN-E) in eight patients (10.7%), middle cluneal nerve entrapment (MCN-E) in nine patients (12.0%), sacroiliac joint (SIJ) pain in five patients (6.7%), and gluteus medius muscle (GMeM) pain in three patients (4.0%). The average numerical rating scale (NRS) scores for pain changed from 7.5 ± 1.5 before treatment to 1.3 ± 0.9 at discharge (p < 0.05). Conclusion Osteoporotic acute vertebral fracture (14.7%) was identified as the cause of LBP in older adults. Block therapy for PLSD may aid in the diagnosis and treatment of non-specific LBP.

[A patient with vertebral artery dissection who initially suffered from pharyngeal pain].

We have encountered a case of a patient with bilateral vertebral artery (VA) dissection who suffered from severe pharyngeal pain. A 61-year-old man, who initially visited a nearby hospital for investigation of mild headache, was pointed out to have a left VA aneurysm. The next morning, severe pharyngeal pain on the right side suddenly occurred. The cause was unknown even when consultation was made to an otolaryngology and oral and maxillofacial surgeon. Sore throat improved in two days. On the 12th day after pharyngeal pain, the patient entered our hospital with a diagnosis of VA dissection. Imaging studies indicated severe stenosis of the right VA and an aneurysm of the left VA which confirmed the diagnosis of bilateral VA dissection. After severe stenosis of the right VA improved a little, the trapping of the left VA aneurysm was performed with bypass surgery of the occipital artery to the posterior inferior cerebellar artery. Although there have been reports of glossopharyngeal neuralgia due to compression of dissective aneurysms of VA, no report exists in terms of a sore throat due to VA dissection without glossopharyngeal neuralgia. This symptom was considered to be involved in the referred pain.

Middle cluneal nerve entrapment neuropathy attributable to lumbar disc herniation.

BACKGROUND: Middle cluneal nerve entrapment neuropathy (MCN-EN) is a known cause of low back pain (LBP). Here, we succeeded in treating a patient with a lumbar disc herniation who actually had MCN-EN with a nerve block and neurolysis. CASE DESCRIPTION: A 52-year-old female presented with severe left lower back and lateral thigh pain making it difficult to walk. The lumbar MRI revealed a disc herniation on the left at the L5/S1 level. On palpation, we identified a trigger point on the buttock where the MCN penetrates the long posterior sacroiliac ligament between the posterior superior and inferior iliac spine. Two left-sided MCN blocks, followed by the left MCN neurolysis procedure, were performed under local anesthesia. At the last follow-up, 10 months after surgery, the LBP has not recurred, and she requires no medications for pain control. CONCLUSION: Here, a patient with a left-sided L5S1 disc herniation and low back/leg pain was successfully treated for MCN-EN with nerve block followed by neurolysis.

Treatment of Coexisting Paralumbar Spine Diseases in Patients with Lumbar Disc Herniation.

Lumbar disc herniation (LDH) elicits low back pain (LBP) and lower-limb symptoms. Paralumbar spine disease (PLSD), for example, superior cluneal nerve/middle cluneal nerve entrapment (SCN-EN, MCN-EN) and sacroiliac joint pain (SIJ), may be attributable to LDH whose treatment may not ameliorate their symptoms. We treated LDH patients and addressed their coexisting PLSDs. We retrospectively analyzed the effects of targeted block therapy for PLSD in 47 patients with LDH. They were 23 men and 24 women ranging in age from 21 to 79 years. They were seen between August 2014 and October 2018, within 3 weeks of LDH onset. PLSD was diagnosed based on the symptoms of patients whose pain was not controlled by oral medications. The treatment outcome was assessed by comparing the numerical rating scale (NRS) and the Roland-Morris Disability Questionnaire (RDQ) score recorded before and 2 weeks after last block treatment. Of the 47 patients with LDH, 2 suffered no LBP and 30 reported tenderness in the low back. We performed block therapy in 13 patients; 9 (19.1%) had concurrent PLSD and experienced pain relief. Their NRS improved from 8.1 ± 1.8 before- to 1.3 ± 0.9 after treatment; their RDQ score fell from 11.2 ± 6.0 to 0.9 ± 1.2 (both, p < 0.01). In an LDH patient with MCN-EN alone, MCN neurolysis was performed 2 weeks after a single MCN block proved to be only transiently effective. Paralumbar diseases may coexist in patients with LDH; treatment of the former may alleviate their LBP.

Artery Transposition Using Indocyanine Green for Tarsal Tunnel Decompression.

BACKGROUND: Surgery for idiopathic tarsal tunnel syndrome (TTS) is of limited effectiveness or ineffective. Using indocyanine green video angiography (ICG-VA), we treated idiopathic TTS by posterior tibial artery (PTA) decompression from the posterior tibial nerve (PTN) and evaluated postoperative patency of the PTA. METHODS: We treated 12 patients (12 feet) with idiopathic TTS by PTA decompression from the PTN and transposed its location. Age range of patients was 70-87 years (mean 77.9 years); all patients were operated on under local anesthesia. After a 2-cm skin incision, the flexor retinaculum was resected, and the PTA was decompressed from the PTN. It was then sutured to the flexor retinaculum for decompression and to prevent compression recurrence. ICG-VA was used to confirm the absence of PTA flow disturbance and to inspect the vasa nervorum of the PTN. RESULTS: We encountered no intraoperative or postoperative complications. Postoperatively, ICG-VA confirmed blood flow in the PTA and intactness of the vasa nervorum in all cases. One patient required adjustment of PTA position. All patients reported symptom improvement. CONCLUSIONS: Our surgical method of treating idiopathic TTS under ICG-VA monitoring is simple, safe, and effective.

A Case of Salivary Duct Carcinoma Intracranial Invasion due to Perineural Invasion Through the Facial Nerve.

BACKGROUND: Salivary duct carcinoma (SDC) is a rare parotid tumor that often develops as a rapidly growing mass with a poor prognosis. It has a high rate of distant metastases, sometimes with infiltration along nerves. We describe a case of SDC that originated outside the cranium and extended into the cranium along the path of the facial nerve. CASE DESCRIPTION: A 74-year-old man underwent magnetic resonance imaging at a local hospital, which revealed a tumor in the left internal acoustic canal; the patient was referred to our department. A left facial schwannoma was suspected, and magnetic resonance imaging was performed again 6 months later. Rapid tumor growth was confirmed, and the tumor was resected. The tumor displayed atypical epithelial cells with comedo necrosis and cribriform structure and was diagnosed as SDC. All residual intracranial tumors were removed using the middle fossa approach. The tumor, which was considered to be a primary tumor, was found near the stylomastoid foramen, and it was removed with the parotid gland. Five months after the initial surgery, metastasis to the trigeminal nerve was observed, and this was removed using a retrosigmoid approach, followed by radiation therapy. CONCLUSIONS: All 4 surgical specimens of this case were presented, and the path of tumor progression was examined in detail. Although the primary lesion was small, intracranial invasion along the facial nerve occurred. SDC should be considered as a tumor that can extend into the cranium, even with a small primary lesion.

Characteristics of Low Back Pain due to Superior Cluneal Nerve Entrapment Neuropathy.

Study Design: Retrospective analysis. Purpose: The present study aimed to investigate the features of low back pain (LBP) due to superior cluneal nerve (SCN) entrapment neuropathy (SCN-EN) using the Roland Morris Disability Questionnaire (RMDQ), and to analyze the differences between LBP due to SCN-EN and lumbar spinal canal stenosis (LSS). Overview of Literature: The SCN is derived from the cutaneous branches of the dorsal rami of T11-L5 and passes through the thoracolumbar fascia. LBP due to SCN-EN is exacerbated by various types of lumbar movement, and its features remain to be fully elucidated, often resulting in the misdiagnosis of lumbar spine disorder. Methods: The present study included 35 consecutive patients with SCN-EN treated via nerve blocks or surgical release between April 2016 and August 2017 (SCN-EN group; 16 men, 19 women; mean age, 65.5±17.0 years; age range, 19-89 years). During the same period, 33 patients were surgically treated with LSS (LSS group; 19 men, 14 women; mean age, 65.3±12.0 years; age range, 35-84 years). The characteristics of LBP were then compared between patients with SCN-EN and those with LSS using the RMDQ. Results: The duration of disease was significantly longer in the SCN-EN group than in the LSS group (26.0 vs. 16.0 months, p =0.012). Median RMDQ scores were significantly higher in the SCN-EN group (13 points; interquartile range, 8-15 points) than in the LSS group (7 points; interquartile range, 4-9 points; p <0.001). For seven items (question number 1, 8, 11, and 20-23), the ratio of positive responses was higher in the SCN-EN group than in the LSS group. Conclusions: Patients with SCN-EN exhibit significantly higher RMDQ scores and greater levels of disability due to LBP than patients with LSS. The findings further demonstrate that SCN-EN may affect physical and psychological function.

Clinical Features and Surgical Treatment of Superficial Peroneal Nerve Entrapment Neuropathy.

Superficial peroneal nerve (S-PN) entrapment neuropathy (S-PNEN) is comparatively rare and may be an elusive clinical entity. There is yet no established surgical procedure to treat idiopathic S-PNEN. We report our surgical treatment and clinical outcomes. We surgically treated 5 patients (6 sites) with S-PNEN. The 2 men and 3 women ranged in age from 67 to 91 years; one patient presented with bilateral leg involvement. Mean post-operative follow-up was 25.3 months. We recorded their symptoms before- and at the latest follow-up visit after surgery using a Numerical Rating Scale and the Japan Orthopedic Association score to evaluate the affected area. We microsurgically decompressed the affected S-PN under local anesthesia without a proximal tourniquet. We made a linear skin incision along the S-PN and performed wide S-PN decompression from its insertion point at the peroneal tunnel to the peroneus longus muscle (PLM) to the point where the S-PN penetrated the deep fascia. One patient who had undergone decompression in the area of a Tinel-like sign at the initial surgery suffered symptom recurrence and required re-operation 4 months later. We performed additional extensive decompression to address several sites with a Tinel-like sign. All 5 operated patients reported symptom improvement. In patients with idiopathic S-PNEN, neurolysis under local anesthesia may be curative. Decompression involving only the Tinel area may not be sufficient and it may be necessary to include the area from the PLM to the peroneal nerve exit point along the S-PN.

Surgical treatment of middle cluneal nerve entrapment neuropathy: technical note.

OBJECTIVE The etiology of low-back pain (LBP) is heterogeneous and is unknown in some patients with chronic pain. Superior cluneal nerve entrapment has been proposed as a causative factor, and some patients suffer severe symptoms. The middle cluneal nerve (MCN) is also implicated in the elicitation of LBP, and its clinical course and etiology remain unclear. The authors report the preliminary outcomes of a less invasive microsurgical release procedure to address MCN entrapment (MCN-E). METHODS The authors enrolled 11 patients (13 sites) with intractable LBP judged to be due to MCN-E. The group included 3 men and 8 women ranging in age from 52 to 86 years. Microscopic MCN neurolysis was performed under local anesthesia with the patient in the prone position. Postoperatively, all patients were allowed to walk freely with no restrictions. The mean follow-up period was 10.5 months. LBP severity was evaluated on the numerical rating scale (NRS) and by the Japanese Orthopaedic Association (JOA) and the Roland-Morris Disability Questionnaire (RDQ) scores. RESULTS All patients suffered buttock pain, and 9 also had leg symptoms. The symptoms were aggravated by standing, lumbar flexion, rolling over, prolonged sitting, and especially by walking. The numbers of nerve branches addressed during MCN neurolysis were 1 in 9 patients, 2 in 1 patient, and 3 in 1 patient. One patient required reoperation due to insufficient decompression originally. There were no local or systemic complications during or after surgery. Postoperatively, the symptoms of all patients improved statistically significantly; the mean NRS score fell from 7.0 to 1.4, the mean RDQ from 10.8 to 1.4, and the mean JOA score rose from 13.7 to 23.6. CONCLUSIONS Less invasive MCN neurolysis performed under local anesthesia is useful for LBP caused by MCN-E. In patients with intractable LBP, MCN-E should be considered.

Utility of cone-beam computed tomography angiography for the assessment of vertebral artery dissection.

Vertebral artery dissection (VAD) has been recognized as a cause of headache and stroke. Accurate evaluation of dissection using several modalities such as catheter-based angiography, CT angiography (CTA), and magnetic resonance imaging (MRI) is essential for subsequent management. The aim of this retrospective study is to compare cone-beam computed tomography angiography (CBCT-A) with other image modalities for the evaluation of the detailed structures of VAD. Twenty-five consecutive cases identified as having VAD were included. They underwent catheter-based angiography (2D-digital subtraction angiography [DSA], 3D-DSA, and CBCT-A), CTA, and MRI for the diagnosis of VAD. CBCT-A was performed following conventional angiography. Dissecting lesions were evaluated for the presence of intimal flap/double lumen, wall thickening, and enhancement of outer wall. This study results showed that CBCT-A was the most superior modality to detect intimal flap/double lumen (found in 56% of the cases) due to its high spatial resolution. MRI was superior for the assessment of wall thickening as an intramural hematoma in 76% of the cases. However, wall thickening was detected in 44% of cases using CBCT-A. In 5 cases, enhancement of outer wall was identified only in CBCT-A. In conclusion, CBCT-A provides detailed luminal and wall morphology of VADs. CBCT-A is useful for the accurate diagnosis of VADs.

Undiagnosed Peripheral Nerve Disease in Patients with Failed Lumbar Disc Surgery.

STUDY DESIGN: Retrospective study (level of evidence=3). PURPOSE: We examine the relationship between residual symptoms after discectomy for lumbar disc herniation and peripheral nerve (PN) neuropathy. OVERVIEW OF LITERATURE: Patients may report persistent or recurrent symptoms after lumbar disc herniation surgery; others fail to respond to a variety of treatments. Some PN neuropathies elicit symptoms similar to those of lumbar spine disease. METHODS: We retrospectively analyzed data for 13 patients treated for persistent (n=2) or recurrent (n=11) low back pain (LBP) and/or leg pain after primary lumbar discectomy. RESULTS: Lumbar re-operation was required for four patients (three with recurrent lumbar disc herniation and one with lumbar canal stenosis). Superior cluneal nerve (SCN) entrapment neuropathy (EN) was noted in 12 patients; SCN block improved the symptoms for eight of these patients. In total, nine patients underwent PN surgery (SCN-EN, n=4; peroneal nerve EN, n=3; tarsal tunnel syndrome, n=1). Their symptoms improved significantly. CONCLUSIONS: Concomitant PN disease should be considered for patients with failed back surgery syndrome manifesting as persistent or recurrent LBP.