Daijiro Morimoto

Surgical treatment of superior cluneal nerve entrapment neuropathy

OBJECT Superior cluneal nerve (SCN) entrapment neuropathy is a poorly understood clinical entity that can produce low-back pain. The authors report a less-invasive surgical treatment for SCN entrapment neuropathy that can be performed with local anesthesia. METHODS From November 2010 through November 2011, the authors performed surgery in 34 patients (age range 18-83 years; mean 64 years) with SCN entrapment neuropathy. The entrapment was unilateral in 13 patients and bilateral in 21. The mean postoperative follow-up period was 10 months (range 6-18 months). After the site was blocked with local anesthesia, the thoracolumbar fascia of the orifice was dissected with microscissors in a distal-to-rostral direction along the SCN to release the entrapped nerve. RESULTS were evaluated according to Japanese Orthopaedic Association (JOA) and Roland-Morris Disability Questionnaire (RMDQ) scores. Results In all 34 patients, the SCN penetrated the orifice of the thoracolumbar fascia and could be released by dissection of the fascia. There were no intraoperative surgery-related complications. For all patients, surgery was effective; JOA and RMDQ scores indicated significant improvement (p < 0.05). CONCLUSIONS For patients with low-back pain, SCN entrapment neuropathy must be considered as a causative factor. Treatment by less-invasive surgery, with local anesthesia, yielded excellent clinical outcomes.

The usefulness of ICG video angiography in the surgical treatment of superior cluneal nerve entrapment neuropathy

Superior cluneal nerve (SCN) entrapment neuropathy is a known cause of low back pain. Although surgical release at the entrapment point of the osteofibrous orifice is effective, intraoperative identification of the thin SCN in thick fat tissue and confirmation of sufficient decompression are difficult. Intraoperative indocyanine green video angiography (ICG-VA) is simple, clearly demonstrates the vascular flow dynamics, and provides real-time information on vascular patency and flow. The peripheral nerve is supplied from epineurial vessels around the nerve (vasa nervorum), and the authors now present the first ICG-VA documentation of the technique and usefulness of peripheral nerve neurolysis surgery to treat SCN entrapment neuropathy in 16 locally anesthetized patients. Clinical outcomes were assessed with the Roland-Morris Disability Questionnaire before surgery and at the latest follow-up after surgery. Indocyanine green video angiography was useful for identifying the SCN in fat tissue. It showed that the SCN penetrated and was entrapped by the thoracolumbar fascia through the orifice just before crossing over the iliac crest in all patients. The SCN was decompressed by dissection of the fascia from the orifice. Indocyanine green video angiography visualized the SCN and its termination at the entrapment point. After sufficient decompression, the SCN was clearly visualized on ICG-VA images. Low back pain improved significantly, from a preoperative Roland-Morris Questionnaire score of 13.8 to a postoperative score of 1.3 at the last follow-up visit (p < 0.05). The authors suggest that ICG-VA is useful for the inspection of peripheral nerves such as the SCN and helps to identify the SCN and to confirm sufficient decompression at surgery for SCN entrapment.

Ketamine for acute neuropathic pain in patients with spinal cord injury

Ketamine, an N-methyl-d-aspartic acid (NMDA) receptor antagonist, may be useful for treating neuropathic pain, which is often difficult to control. We report a prospective study of 13 patients with acute neuropathic pain due to spinal cord injury (SCI) treated with ketamine. All underwent a test challenge with 5mg ketamine. Patients with satisfactory responses were then treated intravenously and subsequently perorally with ketamine. Pre- and post-treatment pain was recorded on a visual analogue scale. All 13 patients responded positively to the ketamine test challenge and underwent continued ketamine administration. At the cessation of treatment and alter at final follow up, pain was decreased by 74.7% and 96.8%, respectively. The average administration period was 17.2 days; it was longer (59 days) in one patient treated in the subacute phase. All patients suffered allodynia-type pain and experienced 30% or less of their original pain intensity upon test challenge. Side effects were noted in five patients, although their severity did not require treatment cessation. In patients with SCI, ketamine reduced allodynia. Particularly good results were obtained in patients treated in the acute phase and these patients did not experience post-treatment symptom recurrence. Our results suggest that in patients with SCI, ketamine is useful for treating neuropathic pain in the acute phase.

Anterior vertebral artery decompression with an ultrasonic bone curette to treat bow hunter’s syndrome

SummaryWe report a patient with bow hunter’s syndrome who was treated by anterior decompression of the vertebral artery (VA) using an ultrasonic bone curette (SONOPET). This 60-year-old man reported almost losing consciousness upon head rotation. Although the right VA appeared normal at the natural head position, upon left head rotation it became completely occluded at the transverse foramen of C2. We performed anterior decompression of the right VA at the axis using a high-speed drill and SONOPET. For anterior decompression of the VA in a deep and narrow operative field, we recommend use of SONOPET, which permits safe, easy bone dissection.

Treatment of low back pain in patients with vertebral compression fractures and superior cluneal nerve entrapment neuropathies

Background: Superior cluneal nerve entrapment neuropathy (SCN-EN) may contribute to low back pain (LBP). However, it is often misdiagnosed as lumbar spine disorder and poorly understood. Methods: Between April 2012 and September 2013, we treated 27 patients (3 men, 24 women; mean age 75.0 years) with LBP due to SCN-EN elicited by vertebral compression fractures. Symptoms were unilateral in 4 patients and bilateral in 23 patients. The interval between symptom onset and treatment averaged 10.8 months; the mean postoperative follow-up period was 19.0 months. The clinical outcomes were assessed utilizing the numeric rating scale (NRS) for LBP, the Japanese Orthopedic Association (JOA) score, and the Roland–Morris Disability Questionnaire (RDQ) before and after treatment (e.g., until the latest follow-up). Results: LBP in 17 patients was immediately improved by SCN block only. The remaining 10 patients required surgery (involving 18 sites) as SCN blocks were only transiently effective. Operative intervention resulted in the immediate and continued improvement of their LBP. Notably, their NRS decreased from 7.4 to 1.5, their RDQ scores from 19.6 to 7.0, and their JOA scores increased from 10.7 to 20.3. Conclusions: In this series, 27 patients with LBP due to SCN-EN responded either to SCN blocks (17 patients) or surgical release of SCN entrapment (10 patients at 18 sites).

Microsurgical Decompression for Peroneal Nerve Entrapment Neuropathy.

Peroneal nerve entrapment neuropathy (PNEN) is one cause of numbness and pain in the lateral lower thigh and instep, and of motor weakness of the extensors of the toes and ankle. We report a less invasive surgical procedure performed under local anesthesia to treat PNEN and our preliminary outcomes. We treated 22 patients (33 legs), 7 men and 15 women, whose average age was 66 years. The mean postoperative follow-up period was 40 months. All patients complained of pain or paresthesia of the lateral aspect of affected lower thigh and instep; all manifested a Tinel-like sign at the entrapment point. As all had undergone unsuccessful conservative treatment, we performed microsurgical decompression under local anesthesia. Of 19 patients who had undergone lumbar spinal surgery (LSS), 9 suffered residual symptoms attributable to PNEN. While complete symptom abatement was obtained in the other 10 they later developed PNEN-induced new symptoms. Motor weakness of the extensors of the toes and ankle [manual muscle testing (MMT) 4/5] was observed preoperatively in 8 patients; it was relieved by microsurgical decompression. Based on self-assessments, all 22 patients were satisfied with the results of surgery. PNEN should be considered as a possible differential diagnosis in patients with L5 neuropathy due to lumbar degenerative disease, and as a causative factor of residual symptoms after LSS. PNEN can be successfully addressed by less-invasive surgery performed under local anesthesia.

Low Back Pain Caused by Superior Cluneal Nerve Entrapment Neuropathy in Patients with Parkinson Disease

n patients with Parkinson disease (PD), postural abnormalities and increased muscle tonus lead to musculoskeletal I problems. The incidence of such problems was significantly higher in patients with PD than in an age-matched control group comprising patients with stroke and brain tumor. Low back pain (LBP) in particular was reported more frequently by patients with PD; in approximately 50%, it negatively affected their quality of life and activities of daily living (ADL). It is difficult to treat LBP in patients with PD, and the results of surgery to address their spinal diseases are unsatisfactory.

Radiological study of the sandwich method in cervical anterior fusion using autologous vertebral bone grafts

Autologous bone grafts from cervical vertebral bodies (Williams-Isu method) are used for anterior fusion of the cervical spine. When adequate amounts of bone cannot be harvested from the vertebral body, hydroxyapatite (a ceramic) is placed between the bone grafts (the sandwich method). We conducted a radiological study to examine the efficacy of the sandwich method by comparing the alignment of the whole spine and the fused segment between patients who had received a sandwich graft (n=20) and a control group (n=20). Although there was no difference between the two groups with respect to the alignment of the whole spine, the alignment and height of the fused segment was significantly better in the patients in the sandwich graft group. In both groups the position of the anterior edge of the graft and the loss in the angle of the fused segment were significantly correlated (p<0.05). We found that the sandwich method not only reinforced the graft, but also yielded better results with respect to the angle and height of the fused segment.

Long-term Outcome of Surgical Treatment for Superior Cluneal Nerve Entrapment Neuropathy

Study Design. Prospective observational cohort study. Objective. The objective of this study was to present the long-term surgical outcomes of operative treatment for superior cluneal nerve (SCN) entrapment neuropathy (SCNEN) and to analyze the causes of poor results and further treatment required. Summary of Background Data. There are a few reports of the outcomes of surgical treatment for SCNEN, and most studies describe results for operations conducted under general anesthesia with short follow-up periods. Methods. Surgery was performed for SCNEN in 52 consecutive patients on 79 sides, excluding patients who had undergone previous surgery on the lumbar spine. Entrapment was unilateral in 25 patients and bilateral in 27. The mean postoperative follow-up period was 41.3 months (range, 29–58 months). All patients had received conservative treatment without improvements, and operations were performed under local anesthesia. Results. Twenty-three cases (44%) involved only low-back pain (LBP), and 31 cases (60%) involved LBP associated with leg numbness or pain. The mean number of SCN branches decompressed in the operative field at the first operation was 1.4 (range, 1–4 branches). There were no local or systemic complications during or after the operation. All patients reported symptom improvement, but LBP caused by SCNEN recurrence was reported for 10 sides (13%) in seven patients who subsequently underwent repeat surgery. In the second surgery, the number of additionally treated SCN branches was 2.0 (range, 1–5). Additional surgeries were performed in two cases for lumbar disorders. All patients showed significant improvement at the last follow-up visit (P < 0.05), including those who developed recurrence. Conclusion. Long-term outcomes of surgical treatment for SCNEN were satisfactory. For prevention of recurrence, as many SCN branches as possible should be decompressed in the operation field during the first operation. Level of Evidence: 4

Neurovascular bundle decompression without excessive dissection for tarsal tunnel syndrome.

Tarsal tunnel syndrome (TTS) is an entrapment neuropathy of the posterior tibial nerve and its branches in the tarsal tunnel. We present our less invasive surgical treatment of TTS in 69 patients (116 feet) and their clinical outcomes. The mean follow-up period was 64.6 months. With the patient under local anesthesia we use a microscope to perform sharp dissection of the flexor retinaculum and remove the connective tissues surrounding the posterior tibial nerve and vessels. To prevent postoperative adhesion and delayed neuropathy, decompression is performed to achieve symptom improvement without excessive dissection. Decompression is considered complete when the patient reports intraoperative symptom abatement and arterial pulsation is sufficient. The sensation of numbness and/or pain and of foreign substance adhesion was reduced in 92% and 95% of our patients, respectively. In self-assessments, 47 patients (68%) reported the treatment outcome as satisfactory, 15 (22%) as acceptable, and 7 (10%) were dissatisfied. Of 116 feet, 4 (3%) required re-operation, initial decompression was insufficient in 2 feet and further decompression was performed; in the other 2 feet improvement was achieved by decompression of the distal tarsal tunnel. Our surgical method involves neurovascular bundle decompression to obtain sufficient arterial pulsation. As we use local anesthesia, we can confirm symptom improvement intraoperatively, thereby avoiding unnecessary excessive dissection. Our method is simple, safe, and without detailed nerve dissection and it prevents postoperative adhesion.