Superior Cluneal Nerve Research Articles

Surgical treatment of superior cluneal nerve entrapment neuropathy

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. 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. 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). 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.

Anatomic Considerations for Posterior Iliac Crest Bone Procurement

The aim of this study was to identify the relative anatomic locations of relevant vital structures at risk for injury during posterior iliac crest bone graft procurement. Twenty-one cadavers yielded 39 intact posterior ilia for dissection. The posterior superior iliac spine (PSIS) was used as the primary reference landmark. Measurements were made to the medial branch of the superior cluneal nerves, the superior branch of the middle cluneal nerves, the sciatic notch, and the superior gluteal vessels. Distances from the spinal midline to the superior cluneal nerves were recorded. The average distances from the PSIS to the superior and middle cluneal nerves, greater sciatic notch, and superior gluteal vessels were 5.7 cm (standard deviation, 1.22 cm), 6.55 cm (standard deviation, 1.53 cm), 5.3 cm (standard deviation, 0.71 cm), and 5.4 cm (standard deviation, 0.95 cm), respectively. The most medial superior cluneal nerve was identified at 3.0 to 4.9 cm from the PSIS in 23% of cases, at 5.0 to 6.9 cm from the PSIS in 61.5% of cases, and farther than 7.0 cm from the PSIS in 15.4% of cases. This study illustrates that the most medial superior cluneal nerve is often closer to the PSIS than previously described and the same holds true for the greater sciatic notch and superior gluteal vessels. Knowledge of the anatomic locations of these important structures should allow the surgeon to avoid or decrease the complication rate of bone procurement from the posterior ilium.

Reconstruction of the sacral region using the lumbo-gluteal sensory flap

Local skin flaps are used for reconstruction of sacral decubitus ulcers because of their structural endurance against the patient's weight. However, a major concern is associated with decubitus recurrence after repair. Sensory flaps are one choice to prevent recurrence. Thus, we reconstructed sacral decubitus ulcers using Nakajima's lumbo-gluteal flap as a sensory flap. Two patients with unstable sacral scars caused by decubitus ulcers were treated operatively. Neither had spinal cord injury, and buttock sensation thus remained. The flap's proximal end was designed on the posterior iliac crest and included the lateral dorsal cutaneous branch of the fourth lumbar artery as examined preoperatively with a Doppler stethoscope. The distal end was beyond the gluteal fold in case 1, but not in case 2. We subcutaneously dissected the vascular pedicle and the superior cluneal nerve located at the proximal portion of the flap after resection of the unstable scar. We then elevated the flap beneath the fascia of the gluteus maximus of the right buttock, preserving the nerve, artery and subcutaneous tissue as one pedicle, and transferred the flap to the defect. In case 1, 2cm of the distal end of the flap was lost. The sensation of the proximal two-thirds of the flap was identical to that of the contralateral buttock. However, the distal one-third of the flap, which was elevated from the area caudal to the gluteal fold, had insufficient sensation. Case 2 had complete flap survival and sufficient sensation in all areas of the flap. Decubitus recurrence has not occurred in 7 years in case 1 and in 9 months in case 2. This flap is useful for reconstruction of sacral decubitus ulcers if sensory function of the buttock remains and may be best designed as not extending beyond the gluteal fold.

Medial superior cluneal nerve entrapment neuropathy in military personnel; diagnosis and etiologic factors

Pain caused by medial superior cluneal nerve entrapment (MSCNE) is an infrequent cause of unilateral low back pain. There is limited information about this neuropathy in the literature. In this study, the etiologic factors leading to this clinical entity were evaluated and also the clinical and imaging findings were examined. The study was conducted in 3 groups. The study group included 25 patients with MSCNE, the hernia group included 25 patients with herniated nucleosus pulposus and the control group included 25 healthy subjects. The initial evaluation included lumbar computerized tomography (CT) and magnetic resonance imaging (MRI) in the study and the hernia groups. The comparisons between these two groups were made by using clinical assessment questionnaires (SF-36 mental and physical health scores and Oswestry scale). Additionally, all three groups were compared by lumbosacral radiographies and low back superficial ultrasonographies. As treatment, 1 ml of prilocaine combined with 1 ml of steroid injection was used in the study group. In the study group, there was no disc herniation, facet joint problems, spinal stenosis or spondylolisthesis detected by CT or MRI. The SF-36 mental health score before treatment was lower in the study group than in the hernia group. The ultrasonographic examination detected a paravertebral hypoechogenic globular-shaped muscle disorganization associated with lipomatous degeneration exclusively localized to the trigger point in the study group. Both the mean soft tissue and the periiliac band thickness were significantly higher in the study group than in the other two groups. The lumbosacral radiographies did not show any significant difference in either the degree of lumbar spinal lordosis or the intercristal line levels among the three groups. This prospective study depicts the etiologic factors, ultrasonographic features and treatment protocol of MSCNE which is usually an underestimated cause of the low-back pain. Diagnostic study, Level I-1 (prospective study).

Entrapment of the Medial Branch of the Superior Cluneal Nerve – a Previously Unrecognized Cause of Lower Back Pain in Cricket Fast Bowlers

Cricket fast bowlers have a high incidence of injury and are prone to back problems that can become debilitating and foreshorten their careers. We present a case of superior cluneal nerve (SCN) entrapment neuropathy as a previously unrecognized etiology of lower back pain in a professional cricket fast bowler, often misdiagnosed as a lumbar spine disorder. We believe that the SCN may be susceptible to compression related to repetitive contraction of the back musculature, in particular the Thoraco-lumbar erector spinae (TLES) and Latissimus dorsi which contribute to a fibro-osseous tunnel through which the SCN runs. The problem can be readily treated with surgical decompression and patients can expect a return to near full function. Clinicians should be aware of this diagnosis when investigating athletes for chronic lower back pain. J Med Cases. 2011;2(3):101-103 doi: https://doi.org/10.4021/jmc167w

Anatomy and landmarks for the superior and middle cluneal nerves: application to posterior iliac crest harvest and entrapment syndromes

To date, only scant descriptions of the cluneal nerves are available. As these nerves, and especially the superior group, may be encountered and injured during posterior iliac crest harvest for spinal arthrodesis procedures, the present study was performed to better elucidate their anatomy and to provide anatomical landmarks for their localization. The superior and middle cluneal nerves were dissected from their origin to termination in 20 cadaveric sides. The distance between the posterior superior iliac spine (PSIS) and superior cluneal nerves at the iliac crest and the distance between this bony prominence and the origin of the middle cluneals were measured. The specific course of each nerve was documented, and the diameter and length of all cluneal nerves were measured. Superior and middle cluneal nerves were found on all sides. An intermediate superior cluneal nerve and lateral superior cluneal nerve were not identified on 4 and 5 sides, respectively. The superior cluneal nerves always passed through the psoas major and paraspinal muscles and traveled posterior to the quadratus lumborum. The mean diameters of the superior and middle cluneal nerves were 1.1 and 0.8 mm, respectively. From the PSIS, the superior cluneal branches passed at means of 5, 6.5, and 7.3 cm laterally on the iliac crest. At their origin, the middle cluneal nerves had mean distances of 2 cm superior to the PSIS, 0 cm from the PSIS, and 1.5 cm inferior to the PSIS. In their course, the middle cluneal nerves traversed the paraspinal muscles attaching onto the dorsal sacrum. Knowledge of the cutaneous nerves that cross the posterior aspect of the iliac crest may assist in avoiding their injury during bone harvest. Additionally, an understanding of the anatomical pathway that these nerves take may be useful in decompressive procedures for entrapment syndromes involving the cluneal nerves.

Gluteal-Sparing Approach for Posterior Iliac Crest Bone Graft

Retrospective clinical series. Description of alternative technique for the harvesting of posterior iliac crest bone graft (ICBG) and assessment of associated morbidity. Although posterior ICBG operations are common, they are often reported to result in significant morbidity. A recent emphasis on the morbidity of ICBG has helped to fuel the costly growth in clinical use of alternatives, such as bone morphogenetic protein-2. Many studies have reported a variety of complications related to iliac crest donor sites, but the most common reported morbidity is pain and/or decreased sensation over the ICBG site. This study is a retrospective review of all patients in the practice of the senior author (T.F.A.) during the study period who received a lumbar fusion with autogenous bone harvested from the posterior iliac crest and accessed by the surgical approach described. Outcomes were assessed by a pain questionnaire determining the site of pain and its magnitude on visual analog scale. Pain on the harvested side was compared with that on the contralateral side, and overall procedure satisfaction was assessed. Statistical analysis was performed using analysis of variance, the Pearson chi2 test, and the Student t test. Any value of P < 0.05 was considered significant. Of 120 patients eligible for the study, 92 patients (77%) were available for follow-up. The patients were interviewed on an average of 24 months (+/-14 months) after their operation. The vast majority of patients (88%, n = 81) had no significant difference in pain or had less pain over the ICBG site than the contralateral side. Eleven patients (12%) experienced significantly greater pain at the ICBG site than over the contralateral side (visual analog scale difference >1). There were 7 patients (8%) in the series with significantly greater pain over the contralateral iliac crest than at the ICBG site. The likelihood of significant pain over the harvested ICBG site was not statistically greater than the likelihood of contralateral iliac crest pain (P = 0.23). One patient (1%) had sensory loss in the superior cluneal nerve distribution. There was 1 patient with an infection that involved the ICBG site and required irrigation and debridement and intravenous antibiotics. Seventy-two patients (78%) stated that they were very satisfied with the operation, 13 (14%) were somewhat satisfied, and 7 (8%) were not satisfied. Although it is difficult to directly compare our results to those reported in other studies, we conclude that the rate of significant chronic sequelae related to this method of harvesting bone from the posterior iliac crest is low. Our findings may be due to the avoidance in this technique of disruption of the gluteal musculature and preservation of the lateral wall of the ilium. The methods used in other studies to estimate the prevalence of chronic pain related to posterior iliac crest bone grafting after lumbar spinal surgery may grossly overestimate this prevalence.

Superior Cluneal Nerve Block for Treatment of Buttock Abscesses in the Emergency Department

The buttock is a common location for cutaneous abscesses among patients presenting for emergency department care. Procedural pain management sufficient to permit adequate incision and drainage often requires moderate sedation or general anesthesia. We describe a patient with a buttock abscess who successfully underwent incision and drainage with a regional superior cluneal nerve blockade instead of moderate sedation. Our experience suggests that superior cluneal nerve blockade may reduce the need for procedural sedation, expedite care, and reduce costs for some patients presenting with buttock abscesses.

Validity of Cross-friction Algometry Procedure in Referred Muscle Pain Syndromes

Deep cross-friction pressure with a finger or an elbow in the proximal gluteal region causes a sciaticlike pain along the side of the thigh and the leg as a clinical presence of referred pain (RP) in patients with nonspecific low back pain (LBP). This study investigated the reliability and discriminative ability of experimentally provoked RP as a result of deep cross-friction with the aid of a Fischer algometer. The new clinical examination method measures the provoked RP threshold resulting in an outcome, expressed in kg/cm2. Forty two patients with subacute LBP (3 to 12 wk) participated in a prospective clinical trial. The outcome was assessed by means of the standard (perpendicular) pressure pain thresholds (PPT) measured with the aid of a Fischer algometer on both sides of the gluteus medius, the provoked RP pain thresholds (PPT-RP) at the location of the medial superior cluneal nerve, the Oswestry Disability Index , and the McGill Pain Questionnaire. The diagnostic criteria for the clinical presence of RP were determined by the patient on the pain chart drawings of the McGill Pain Questionnaire. The criteria for provoked RP were determined by means of PPT-RP with the aid of a Fischer algometer until the patient pointed out the RP zone in the thigh and/or the leg. The interobserver reliability was sufficient for both sides with and without RP (intraclass correlation coefficient>0.97). The test-retest performed independently of the observers ranking, showed a perfect reliability of the PPT-RP measurements (intraclass correlation coefficient>0.98). The PPT-RP at the level of the medial superior cluneal nerve in the subgroup with a clinical presence of RP (N=20) was significantly higher (3.5 kg/cm2) than in the subgroup patients without RP (N=22). The correlation between the factor RP and the PPT-RP was high (R=0.91, P<0.001). The clinically important difference between provoked and clinical presence of RP was found to be higher or lower than 5.6 kg/cm2. The standard PPT measurement of the gluteus medius revealed no significant differences between the subgroups with and without RP. This clinical study support the reliability and discriminative ability of a new method of experimentally provoked RP, using deep cross-friction pressure with the aid of a Fischer algometer in patients with LBP. The experimentally "provoked referred pain threshold" (PPT-RP) values lower than 6 kg/cm correspond clinically with the presence of a referred muscle pain area in the thigh and/or the leg. Further studies of a similar kind are nevertheless needed to confirm those conclusions and to assess the responsiveness of the provoked RP measurements in different treatment follow-up periods.

Posterior Bone Block Distraction Arthrodesis of the Subtalar Joint: A Review of 22 Cases

Twenty-two patients underwent a posterior bone block distraction arthrodesis of the subtalar joint between 1999 and 2006. The indication for surgery was loss of heel height, subtalar joint arthrosis, decreased talar declination with associated tibiotalar impingement, insufficient Achilles tendon function, malalignment of the rear foot, and pain with ambulation. There were 11 male and 11 female patients with a mean age of 46.7 years (range 20 to 71). The mean follow-up period was 27.3 months (range 12 to 63.9 months). Radiographic analysis revealed a mean increase in heel height of 6.09 mm (P= .0001), 5.83 degrees (P= .12) of lateral talocalcaneal angle, 5.5 degrees (P= .06) of talar declination, and 5.23 degrees (P= .07) of calcaneal inclination. The talo-first metatarsal angle increased an average of 4.5 degrees (P= .18). There was a 95.5% union rate. Postoperative complications included nonunion in 1 patient, subsidence of graft (collapse) in 1 patient, wound dehiscence in 3 patients, painful hardware in 7 patients, sural neuritis in 1 patient, superior cluneal nerve dysfunction in 1 patient and one mild varus malunion. Posterior bone block distraction arthrodesis can be successfully used to restore heel height, realign the foot, and decrease the morbidity associated with late complications of calcaneal fractures, as well as, nonunion and/or malunion following subtalar joint arthrodesis, Charcot neuroarthropathy, and avascular necrosis of the talus. 4.

Superior Cluneal Nerve Entrapment Eight Years after Decubitus Surgery

Superior cluneal nerve (SCN) entrapment is one of the infrequent etiologies of low back pain (LBP), which is rarely diagnosed. Few clinical reports have been published in the literature. We present a case of severe LBP radiating to the ipsilateral buttock after decubitus surgery. A 62-year-old man weighing 85 kg presented to the algology department, suffering from severe LBP of 6 months duration. The pain was in the right iliac crest region with radiation to the ipsilateral buttock. After admission, his history was taken, physical examination was performed, and further evaluations were made. He was suspected of having facet and right sacroiliac joint pain. Two tender points were found 6.5 and 7.5 cm to the right of the midline over the iliac crest. Local anesthetic with corticosteroid was injected at the tender points over the right iliac crest. Five minutes after the injection, the pain dissipated. SCN entrapment should be considered in patients who suffer from LBP radiating to the iliac crest and buttock after other causes of LBP have been excluded.

Morbidity of harvesting of bone grafts from the iliac crest for preprosthetic augmentation procedures: A prospective study

It has been the aim of the present prospective clinical study to assess the morbidity following the harvest of bone from the anterior and posterior ilium in elective preprosthetic augmentations. Fifty consecutive healthy patients (30 female, 20 male, mean age 52.5±9.3 years, range 31 years to 65 years) underwent augmentations of implant sites by iliac crest bone grafts. The bone harvest was carried out in 25 cases from the anterior and in 25 cases from the posterior ilium. The superficial sensory function of the skin was determined quantitatively preoperatively, 7 and 30 days after surgery with the ‘Pain and Thermal Sensitivity’ Test (PATH Test). On the same occasions subjective pain on a visual analogue scale (VAS) and gait disturbances were documented. In the PATH Test, for the innervation areas of the lateral femoral cutaneous nerve (LFCN) and the superior and middle cluneal nerves (SMCN) a significant impairment of the superficial sensory function could be found after 1 week and a significant tendency towards recovery after 1 month (warm stimulusLFCNpreop: 37.9±3.0°C, warm stimulusLFCNday7: 38.6±3.2°C, warm stimulusLFCNday30: 37.9±2.9°C, PLFCNwarmpreop/day7=0.023,PLFCNwarmpreop/day30 =0.886, warm stimulusSMCNpreop: 36.1±2.4°C, warm stimulusSMCNday7: 36.6±2.3°C, warm stimulusSMCNday30: 36.3±4.0°C,PSMCNwarmpreop/day7 <0.0005,PSMCNwarmpreop/day30 =0.086). Gait disturbances were seen in seven patients after anterior and in three patients after posterior bone harvest 7 days after surgery (Pgaitdisturbanceanterior/posterior=0.123). After 1 month none of the patients of both groups showed gait disturbances any longer. The maximum subjective pain level was found on the second postoperative day in both groups. It was significantly higher for the anterior approach (VASanteriorday2 7.0±1.5, VASposteriorday2 5.5±1.8,PVASanterior/posteriorday2 =0.004). At day 7 and at day 30, the pain levels did no longer differ significantly (VASanteriorday7 3.7±1.4, VASposteriorday7 3.2±1.6,PVASanterior/posteriorday7 =0.165, VASanteriorday30 1.4±0.7, VASposteriorday30 1.4±0.8,PVASanterior/posteriorday30 =0.724). Because of the lower morbidity of bone harvest from the posterior ilium in the early postoperative phase compared to the anterior approach it seems that it should be preferred in elective augmentation procedures.

Bone-graft harvesting from iliac and fibular donor sites: techniques and complications.

The ilium and the fibula are the most common sites for bone-graft harvesting. The different methods for harvesting iliac bone graft include curettage, trapdoor or splitting techniques for cancellous bone, and the subcrestal-window technique for bicortical graft. A tricortical graft from the anterior ilium should be taken at least 3 cm posterior to the anterior superior iliac spine (ASIS). Iliac donor-site complications include pain, neurovascular injury, avulsion fractures of the ASIS, hematoma, infection, herniation of abdominal contents, gait disturbance, cosmetic deformity, violation of the sacroiliac joint, and ureteral injury. The neurovascular structures at risk for injury during iliac bone-graft harvesting include the lateral femoral cutaneous, iliohypogastric, and ilioinguinal nerves anteriorly and the superior cluneal nerves and superior gluteal neurovascular bundle posteriorly. Violation of the sacroiliac joint can be avoided by limiting the harvested area to 4 cm from the posterior superior iliac spine (PSIS) and by not penetrating the inner cortex. The caudal limit for bone harvesting should be the inferior margin of the roughened area anterior to the PSIS on the outer table to keep from injuring the superior gluteal artery. Potential complications of fibular graft harvesting include neurovascular injury, compartment syndrome, extensor hallucis longus weakness, and ankle instability. The neurovascular structures at risk for injury during fibular bone-graft harvesting include the peroneal nerves and their muscular branches in the proximal third of the fibular shaft and the peroneal vessels in the middle third.

Techniques and Complications of Bone Graft Harvesting

Autogenous bone grafts are frequently harvested for the purposes of bone union and stability. Ilium is the most common site for bone-graft harvesting. Although some donor site complications may be unavoidable, awareness of the anatomy and complications may aid in planning the approach and minimizing the risks. A tricortical graft from the anterior ilium should be taken at least 2 cm posterior to the anterior superior iliac spine(ASIS). Iliac donor-site complications include pain, neurovascular injury, avulsion fractures of the ASIS, hematoma, infection, herniation of abdominal contents, gait disturbance, cosmetic deformity, violation of the sacroiliac joint, and ureteral injury. The neurovascular structures at risk for injury during iliac bone-graft harvesting include the lateral femoral cutaneous, iliohypogastric, and ilioinguinal nerves anteriorly and the superior cluneal nerves and superior gluteal neurovascular bundle posteriorly. Violation of the sacroiliac joint can be avoided by not penetrating the inner cortex. The caudal limit for bone harvesting should be the inferior margin of the roughened area anterior to the PSIS on the outer table to keep from injuring the superior gluteal artery. Strict observation of relevant anatomic considerations will help in avoiding these complications.

Superior cluneal nerve entrapment

Background and Objectives: Pain due to superior cluneal nerve entrapment is an infrequent cause of unilateral low back pain. Here we present a case of acute unilateral low back pain treated by superior cluneal nerve (SCN) block. Case Report: A 55-year-old woman presented to the outpatient clinic suffering from unilateral low back pain localized to right iliac crest and radiating to the right buttock. Her history was taken, physical examination was performed, and a thorough radiologic evaluation was performed to minimize radiculopathy and facet syndromes as causative. After transient pain relief with a diagnostic trigger point injection, entrapment of SCN was diagnosed and therapeutic nerve block with local anesthetic and steroid combination was performed. Conclusion: SCN is prone to entrapment where it passes through the fascia near the posterior iliac crest. Unilateral low back pain and deep tenderness radiating to the ipsilateral buttock are the clinical findings accompanying SCN entrapment. The case presented emphasizes the relief of possible SCN after limiting other etiologic causes of low back pain. Reg Anesth Pain Med 2000;25:648-650.

Identification of a New Therapeutic Approach for Iliac Crest Donor Site Chronic Pain: A Case Report

Identification of a New Therapeutic Approach for Iliac Crest Donor Site Chronic Pain: A Case Report

Letters to the Editor

Dear Sir: We are writing regarding the study by Lu et al.2 The authors of that study described the relationship of the nerve with the iliac crest in 15 dissections and note the presence of an entrapped nerve in two cases. They claim that "The regional anatomy of the superior cluneal nerve has not been well documented in the literature" and that "The actual lesion [of an entrapment neuropathy of this nerve] has not been identified." We think that the available literature has not been researched sufficiently. Garvey et al1 did not describe the clinical basis of superior cluneal nerve entrapment. They merely compared modalities of treating iliac crest trigger points, without going into the origins of, or mechanisms underlying, these trigger points. We were the first to describe the actual entrapment. In our paper which is quoted by the authors,5 and another article published in 1989,4 we presented a comprehensive study of the anatomy of the superior cluneal nerve, showing its distribution and iliac crest crossing patterns. To the best of our knowledge. we were the first to describe, and present photographic evidence of a superior cluneal nerve entrapment syndrome. The only difference between the study by Lu et al and ours is that we dissected 37 cadavers, whereas Lu et al2 examined 15 cadavers. Our broad based study allowed us to describe three different distribution patterns. Furthermore, we recently have published the results of surgical neurolysis in 19 patients with unilateral low back pain related to this entrapment neuropathy.3 Our findings provided evidence of the existence of this neuropathy in vivo. Therefore, the conclusions drawn by Lu et al are correct, but their article lacks originality. The study on which it is based is less extensive than the one performed by us in 1991. Because studies on this subject are few, it would not have affected the value of the paper by Lu et al if the authors had cited our work, to confirm our findings or criticize our statements, as they saw fit. We would be much obliged if you could correct the distorted impression that may have resulted from the publication of the paper by Lu et al. Jean-Yves Maigne, MD Levon Doursounian, MD Paris, France

Anatomic Considerations of Superior Cluneal Nerve at Posterior Iliac Crest Region

No previous studies describe the anatomic relationship of the superior cluneal nerve to the posterior iliac crest and thoracolumbar fascia. In the current study, 15 cadavers were dissected to determine the relationship of the superior cluneal nerve to the posterior iliac crest and thoracolumbar fascia. The distances from the medial branch of the superior cluneal nerve to the posterior superior iliac crest and the midline were 64.7 +/- 5.3 mm and 81.0 +/- 9.2 mm, respectively. The distances between the level of the iliac crest and perforating points of the superior cluneal nerve on the thoracolumbar fascia were 5.8 +/- 1.8 mm inferiorly for the medial branch, 2.2 +/- 1.8 mm superiorly for the intermediate branch, and 12.0 +/- 4.4 mm superiorly for the lateral branch, respectively. The proximal dissection above the perforating point of the nerve showed that the medial branch of the superior cluneal nerve is confined within a tunnel consisting of the thoracolumbar fascia and the superior rim of the iliac crest as it passes over the iliac crest. The intermediate and lateral branches of the superior cluneal nerve either pierce the thoracolumbar fascia or pass through an orifice or fissure in the thoracolumbar fascia. In two specimens, the medial branches of the superior cluneal nerve were constricted within the osteofibrous tunnel. The nerve was entrapped between the rigid fibers of the thoracolumbar fascia and the iliac crest.

Entrapment neuropathy of the medial superior cluneal nerve. Nineteen cases surgically treated, with a minimum of 2 years' follow-up.

In this study, the authors analyzed the results of the release of the medial superior cluneal nerve in a prospective series of 19 patients with suspected entrapment. To ascertain, in selected patients with low back pain, medial superior cluneal nerve entrapment compromise at the posterior iliac crest crossing site, and to evaluate the results of nerve release. A cadaveric study had shown that the medial superior cluneal nerve may be compressed at its transit site through an osseofibrous orifice at the posterior iliac crest. Nineteen patients suffering from unilateral low back pain projecting in the territory of the medial superior cluneal nerve, with a trigger point at the posterior iliac crest and with a positive block test at this level, underwent surgery. Results were excellent in 13 cases (7 of which had suffered from severe compression), and unsatisfactory in 6 cases (including 4 cases in whom no compression could be demonstrated). Entrapment neuropathy of the medial superior cluneal nerve is a rare and easily treatable cause of unilateral low back pain.

Anatomic Considerations for Posterior Iliac Bone Harvesting

This study analyzed bony features of the posterior ilium and relevant vital structures using cadavers and dry ilium specimens. To determine quantitatively the safely zone of the posterior ilium and relevant vital structures with regard to bone graft harvesting. The most frequently used site for bone graft harvesting is the posterior ilium. However, complications related to posterior iliac bone harvesting, such as donor site pain, neurovascular injury, instability of the sacroiliac joint, and herniation of abdominal contents, are still major concerns. Very little research with regard to the quantitative study of the posterior ilium has been reported. Six cadavers (four male, two female) were used for the first part of this study. The posterior superior iliac spine was determined as a reference landmark. The distances from the posterior superior iliac spine to the superior cluneal nerves, the gluteal line, and the superior gluteal vessels were measured. The second part of the study involved 30 adult, dry iliac bony specimens. The posterior iliac region (extra-articular portion) was divided into three zones, and the corresponding dimensions of these zones were measured. The average distances from the posterior superior iliac spine to the superior cluneal nerves, gluteal line, and superior gluteal vessels were 68.8, 26.6, and 62.4 mm, respectively. The average width, height, and maximum thickness for Zone 1 were 34, 27.8, and 17.1 mm, respectively; the measurements for Zone 2 were 16.5, 31.8, and 14.2 mm, respectively. The average height for Zone 3 was 20.4 mm, and the average maximum thickness was 16.8mm. The ideal area of the posterior ilium for bone graft harvesting was found in Zone 1. Zones 2 or 3 may be considered it a greater quantity of cancellous bone graft is required; however, the risk of injury to the sacroiliac joint and superior gluteal vessels in these zones is increased.