The piriformis syndrome

Piriformis syndrome is an often misdiagnosed cause of sciatica, leg, or buttock pain, and disability. The sciatic nerve may be compressed within the buttock by the piriformis muscle, with pain increased by muscular contraction, palpation, or prolonged sitting. A thorough medical history and physical examination are essential to proper diagnosis. Diagnostic testing may be used to differentiate piriformis syndrome from other causes of sciatica, lower extremity weakness, and pain. This article reviews the pathophysiology and management of piriformis syndrome.     

Can Rinne''s test quantify hearing loss?

Several years after undergoing surgery for a malignant melanoma on his left lower back, a 51 year old man developed intermittently severe pain in his left posterior thigh. Plain X-rays showed no abnormality, but computerized tomography and magnetic resonance imaging scans demonstrated an abnormal soft tissue mass in the left sciatic notch. Although a metastasis from the original melanoma was suspected, exploration of the suspicious area revealed only hypertrophy of the left piriformis muscle. This was due to regular gymnasium exercises designed to selectively build up the musculature of the left lower limb, which the patient had undertaken in the firm belief that it would help to prevent a recurrence of his left-sided melanoma. Complete relief of the unilateral piriformis syndrome was achieved by division of the hypertrophied piriformis muscle, thereby relieving the pressure on the left sciatic nerve as it passed through the greater sciatic foramen.     

Usefulness of hepatitis C virus RNA counts by second generation HCV bDNA-probe in chronic hepatitis C based on the HCV genotype

BACKGROUND AND OBJECTIVES: Piriformis syndrome causing sciatica is sometimes refractory to conventional treatments including physical therapy, piriformis injections, and even caudal epidural steroid injections. Surgical release of the piriformis muscle has been described for difficult cases of piriformis syndrome, but is occasionally accompanied by morbidity. Another approach to treating piriformis syndrome is presented. METHODS: A perisciatic injection of steroid using simple landmarks and utilizing a nerve stimulator to locate and inject near the sciatic nerve and into the piriformis muscle is described. RESULTS: Six patients that did not respond to conventional treatments, but did respond to perisciatic steroid injections are presented. CT scan, in one of the patients, confirmed correct needle placement when this technique and landmarks were used. CONCLUSION: Patients with piriformis syndrome who were refractory to conventional treatments but responded to perisciatic injections of steroid are presented.     

The sensory innervation of the hip joint--an anatomical study

Typically obturator nerve blockade is used to relieve hip pain. It sometimes only has a minor effect in resolving symptoms. This clinical observation led us to examine comprehensively the sensory nerve innervation of formalin-fixed hip joint capsules. Following macroscopic preparation, the area of the hip joint capsule was inspected with the aid of an operating microscope. We discovered a separation between the anterior and posterior sensory innervation of the hip joint capsule. The anteromedial innervation was determined by the articular branches of the obturator n. Additionally, the anterior hip joint capsule was innervated by sensory articular branches from the femoral n. In the posterior part we found articular branches from the sciatic n., which in addition to the articular branches from the nerves to the quadratus femoris m., innervate the postero-medial section of the hip joint capsule. Moreover, articular branches of the superior gluteal n. were found, which innervate the posterolateral section of the hip joint capsule. This anatomical study demonstrates that the obturator n. block is insufficient for the treatment of hip pain. Further investigations will determine if these nn. can be reached percutaneously. Effective neural blockade of the hip joint must include the femoral n., the sciatic n. and the superior gluteal n.     

Typing of methicillin-resistant Staphylococcus aureus isolates from Düsseldorf by six genotypic methods

This in vivo double-blind study evaluated the effect of recombinant human glial growth factor 2 (rhGGF2), a Schwann cell mitogen, on the recovery of motor function of rat sciatic nerve following crush injury. Seventy three rats were divided into three groups. Group I (n=5), sham operated; Groups II (n=34) and III (n=34) received a 100 g crush load for 2 h over a 5 mm segment of the sciatic nerve. Group III was treated with 1 mg/kg rhGGF2, via subcutaneous injection one day before nerve crush and daily for the following four days. Group II received an equivalent volume of saline as a control. Motor functional recovery was assessed by calculating the sciatic functional index (SFI) and the recovery rate of tetanic contractile force of the extensor digitorum longus (EDL) muscle. Recovery of nerve function was evident at day 11 after crush in the rhGGF2-treated animals, whereas the nerves in controls were still paralyzed. The rhGGF2-treated animals showed a significant improvement of the SFI between days 11-21 postoperatively when compared to controls. The isometric tetanic contractile force was stronger in the rhGGF2-treated group than in controls, with a significant difference at 40 to 70 Hz stimulus frequencies on day 4. Correlation analysis showed that tetanic contractile force had a linear correlation with the SFI. Histologic assessment indicated that the rhGGF2-treated animals showed less severe degeneration and earlier robust remyelination of axons than controls. The results suggest that treatment with rhGGF2 is effective in promoting nerve regeneration as seen in measurements of functional recovery and qualitative assessment of nerve morphology. The mechanism of GGF's protective effect may be related to its direct action on Schwann cells, stimulating their mitosis as well as inducing neurotrophic factors essential to neuronal maintenance and repair.     

Isolated superior gluteal nerve injury: two case reports

Isolated superior gluteal nerve injury has been infrequently described in the literature, mainly from injections or hip surgery. Its course through the greater sciatic foramen renders it at risk in pelvic or hip trauma. We report 2 cases of electromyographically documented isolated superior gluteal nerve injury following pelvic trauma. These cases illustrate that weakness in hip abduction following pelvic trauma may indicate the presence of a superior gluteal nerve injury, warranting further clinical and electrodiagnostic evaluation.     

Piriformis syndrome: assessment of current practice and literature review

Although piriformis syndrome was initially described in 1928, it has remained a nebulous and controversial diagnosis. A literature review reveals that there is no consensus on the diagnosis or treatment of piriformis syndrome. In addition, a survey of 75 physiatrists revealed that whether the diagnosis of piriformis syndrome even exists is controversial. This survey and literature review examines the diagnosis and treatment of piriformis syndrome. The fact that it remains controversial is likely due to a lack of objective clinical trials.     

Transposition of vertical recti for residual tropias

Transposition of vertical muscles for residual tropia was performed: nasal displacement for exotropia and temporal displacement for esotropia. Five millimeter equal displacement of superior and inferior recti corrected 10 to 14 prism diopter while equal displacement of 7 to 8 mm resulted in correction of 25 prism diopter. Special indications of this procedure may be: (1) residual tropia in cases with severe intractable ambylopia or pathology in one eye where patient and surgeon may be reluctant to operate on the sound eye, or (2) residual tropias of the alternating type in patients who underwent operations in all horizontal muscles of both eyes.     

Further study of hepatitis C virus RNA detection in formalin-fixed, paraffin-embedded liver tissues by ligation-dependent polymerase chain reaction

AIM: Refractive cataract surgery using corneal incisions is aiming at neutralization of preoperative astigmatism. PATIENTS AND METHODS: 61 patients with preoperative astigmatism of 2.25 +/- 0.98 were included in the treatment. A self-sealing corneal tunnel incision measuring 4.0 to 4.1 mm in external diameter and 6.5 to 7.0 mm in internal diameter (stretch incision) was performed on the steeper axis. After capsulorhexis and phacoemulsification a 5 mm PMMA lens was implanted without suturing. Keratometry and corneal topography were performed preoperatively, 3 days and 1 year respectively following surgery. The statistical analysis was based on the Wilcoxon signed ranks test. RESULTS: Surgical induced astigmatism (IA) following superior incisions in cases of astigmatism with the rule (n = 29) amounted to 1.93 +/- 0.97, while lateral incisions in cases of astigmatism against the rule (n = 29) led to an IA of 1.35 +/- 0.73. Axial shifts by more than 30 degrees were 23% following superior incisions and 17%, after lateral incisions. We observed. astigmatic reduction of 1.3 D after superior incisions and 0.7 D following lateral incisions. CONCLUSION: By 4 mm corneal cataract incisions on the steeper axis a high preoperative astigmatism can be reduced significantly without additional keratotomies.     

Radiological anatomy of the vein of Labbé

The development and radiology of the vein of Labbé (VL) were investigated using the brains of 19 aborted human fetuses and 6 normal adults injected at autopsy with radiopaque material through the venous system. Carotid angiograms taken in stereoscopic pairs (110 cases, 167 hemispheres) were also analyzed in detail. Developmental alterations of the cerebral structures, particularly those of the opercula and cerebral sulci, are reflected in our classification of the pial veins of the lateral cerebral convexity into the superior, middle and inferior groups. The anastomotic veins of Trolard and Labbé were already recognizable at the fetal age of 6 to 7 months, as development of the opercula and resultant depression of the insula became advanced. In our series, superficial draining veins opening into the VL were 14 to 20 mm (average 16.8 mm) in length. Anastomoses among the superior, middle and inferior groups were analyzed angiographically: single anastomosis was found in 23 percent of cases, while double and triple anastomoses were found in 32 and 45 percent, respectively. A majority of the veins at the sites of anastomosis were found to have calibers of less than 1 mm. The VL, therefore, should be considered in most cases as an independent major superficial draining venous channel of the cerebral convexity with insignificant connections with the superior and middle groups.     

Hypertrophic pyloric stenosis in infancy. An analysis of treatment outcome

The anatomy of the double or bifid zygomaticus major muscle is investigated in a series of 50 hemifacial cadaver dissections. The double zygomaticus major muscle represents an anatomical variation of this muscle of facial expression. This bifid muscle originates as a single structure from the zygomatic bone. As it travels anteriorly, it then divides at the sub-zygomatic hollow into superior and inferior muscle bundles. The superior bundle inserts at the usual position above the comer of the mouth. The inferior bundle inserts into the modiolus below the corner of the mouth. The incidence of the double zygomaticus major muscle was 34% in the present study, as it was found to be present in 17 of 50 cadaver dissections. This study shows that variation in the individual morphology of the mimetic muscles can be a common finding. Clinically, the double or bifid zygomaticus major muscle may explain the formation of cheek "dimples." The inferior bundle was observed in several specimens to have a dermal attachment along its mid-portion, which tethers the overlying skin. When an individual with this anatomy smiles, traction on the skin may create a dimple due to this dermal tethering effect.     

Systemic venous collateral development after the bidirectional cavopulmonary anastomosis. Prevalence and predictors

OBJECTIVES: To determine the prevalence of systemic venous collaterals after the bidirectional cavopulmonary anastomosis and the factors associated with their development. BACKGROUND: Systemic venous collaterals have been found after cavopulmonary anastomosis. Methods. Cardiac catheterization was performed in 103 patients before and after a bidirectional cavopulmonary anastomosis. RESULTS: After surgery, 51 venous collaterals were identified in 32 patients (31%). Collateral development was associated with an abnormal superior vena caval connection (56% incidence vs. 26% with a single right superior vena cava, p = 0.01) and postoperative factors including pulmonary artery distortion (53% incidence vs. 22% without distortion, p = 0.002); increased superior vena caval mean pressure (14 +/- 5 mm Hg versus 11 +/- 4 mm Hg with no collaterals, p = 0.0002); increased pulmonary artery mean pressure (13 +/- 4 mm Hg vs. 11 +/- 4 mm Hg with no collaterals, p = 0.02); lower right atrial mean pressure (5 +/- 2 mm Hg vs. 6 +/- 3 mm Hg with no collaterals, p = 0.04); and increased mean gradient between superior vena cava and right atrium (8 +/- 3 mm Hg vs. 5 +/- 4 mm Hg with no collaterals, p = 0.0002). Using multiple logistic regression, only this last factor was independently associated with collateral development with an odds ratio per 1 mm Hg of 1.33 (95% CI 1.12-1.58, p = 0.001) for their presence. CONCLUSIONS: Systemic venous collaterals occur frequently after a bidirectional cavopulmonary anastomosis and are found postoperatively when a significant pressure gradient occurs between cava and right atrium.     

Chemotherapy in stage IV (metastatic) non-small-cell lung cancer. Provincial Lung Disease Site Group

After sciatic transection a strong decrease in immunoreactivity occurred, starting at 2 days. After 6, 10, 14, and 20 days survival only 5% of the sciatic motoneurons were strongly labeled for GluR2/3 against 80% in the control situation. From Day 20, GluR2/3 labeling started to increase again, reaching near normal levels at Day 80 after sciatic transection. In contrast, after sciatic crush, the decrease in GluR2/3 labeling in motoneurons was less pronounced and returned to normal in 30 days. In all animals, the GluR1 and GluR4 labeling of motoneurons remained unchanged after sciatic transection or crush. It is concluded that sciatic nerve injury leads to a strong, time-dependent decrease in the expression of GluR2 and 3 subunits in the corresponding motoneurons. As a consequence, AMPA receptors with a different subunit composition may be assembled, leading to a change in the functional properties of these receptors. Moreover, if they lack the GluR2 subunit, they may become calcium permeable.     

Synthesis and characterization of new psoralen derivatives with superior photoreactivity with DNA and RNA

The synthesis of five new psoralen derivatives is described. Three of these, 4'-hydroxymethyl-4,5',8-trimethylpsoralen, 4'-methoxymethyl-4,5',8-trimethylpsoralen, and 4'-aminomethyl-4,5',8-trimethylpsoralen hydrochloride, and characterized with respect to their photoreactivity with DNA and RNA. They are found to be greatly superior to 4,5',8-trimethylpsoralen and 8-methoxypsoralen, the two commonly used psoralens, in their abilities to saturate the photoreactive sites on DNA and RNA without repeated addition of reagent. A simplified mechanism for the photoreaction of psoralens with nucleic acids is presented and provides a basis for understanding the superior properties of these compounds. The compounds have superior reactivity not only with isolated DNA and RNA but also in viruses and in cells. Psoralens are shown for the first time to cross-link RNA double helices.     

The pelvic osteotomy of Chiari: an anatomical study of the hazards and misleading radiographic appearances

The medial displacement osteotomy of Chiari has an established place in the management of older children and adults with severe hip dysplasia. The results claimed for the operation are, however, variable. There have also been reports of sciatic nerve lesions. In this study ten cadavers were operated upon. Chiari osteotomy was performed upon five, and five acted as controls. The hemipelvis was removed from each cadaver; each specimen was deep-frozen and sectioned transversely. The distance of the sciatic nerve from the nearest bony point was measured in each section and the results were recorded graphically. A further radiographic and photographic study was performed to determine whether apparent displacement at the osteotomy might be misleading. The conclusion was drawn that the sciatic nerve is angulated at the osteotomy and further endangered by the risk of bone splintering at the sciatic notch. The radiographic study suggested that some poor clinical results may be explained by a radiological artefact, because there is a tendency for the osteotomy to hinge posteriorly at the sciatic notch opening anteriorly like a book. Radiographs may suggest excellent medial displacement whereas in fact the femoral head is very poorly covered.     

Anemia and malaria in a Yanomami Amerindian population from the southern Venezuelan Amazon

OBJECTIVE: To review experience with 20 women treated for sciatic hernia between 1993 and 1997. METHODS: Patients with chronic pelvic pain and sciatic hernias, identified retrospectively from chart review, were seen during a 46-month period that covered the surgical experience at our institution and included approximately 1100 cases. The median length of follow-up was 13 months (range 3-36). RESULTS: Sciatic hernia was diagnosed in 20 white women with chronic pelvic pain and was treated using laparoscopy. In 14 cases the hernias were right sided, in five they were left sided, and in one they were bilateral. All sciatic hernias contained the ipsilateral ovary alone or with its fallopian tube. All 20 patients reported symptomatic relief at follow-up. CONCLUSION: Sciatic hernia is a cause of chronic pelvic pain and should be considered in the differential diagnosis.     

The efficacy of combination immunotherapy in experimental Pseudomonas sepsis

Immunotherapy has been shown to be an effective adjuvant in the management of septic shock. A neutropenic rat model of septic shock induced by infection with Pseudomonas aeruginosa 12.4.4 (Fisher immunotype 6) was used to determine the relative efficacy of single, double, and triple combination immunotherapy. A Pseudomonas O serotype-specific, opsonophagocytic monoclonal antibody (MAb), polyclonal J5 antiserum, and a MAb directed against tumor necrosis factor-alpha (TNF) were studied as single therapy and in combination. The combination of all three immunotherapeutic agents resulted in a 77% survival rate (33/43 animals). This level of protection was superior to that achieved with any combination of two antibody treatments (50%-60% survival; P = .029) or single antibody therapy (25%-43% survival; P < .001) or compared with a control group (0/25 survivors; P < .0001). Immunotherapy directed against multiple steps of the septic process is more active than single or double antibody regimens and may offer an improved approach to the adjunctive treatment of septic shock.     

Double patch closure of ventricular septal defect with increased pulmonary vascular resistance

BACKGROUND: Closure of a large ventricular septal defect (VSD) in children with elevated pulmonary vascular resistance is associated with significant morbidity and mortality. Pulmonary hypertensive episodes continue to be a major cause of postoperative morbidity and mortality. We designed a fenestrated flap valve double VSD patch in an effort to decrease the morbidity and mortality associated with the closure of a large VSD with elevated pulmonary vascular resistance. METHODS: Eighteen children (mean age, 5.7 years) with a large VSD and elevated pulmonary vascular resistance (mean, 11.4 Wood units) underwent double patch VSD closure using moderately hypothermic cardiopulmonary bypass and cardioplegic arrest. The routine VSD patch was fenestrated (4 to 6 mm) and on the left ventricular side of the patch, a second, smaller patch was attached to the fenestration along its superior margin before closure of the VSD. RESULTS: All children survived operation and were weaned from inotropic and ventilator support within 48 hours postoperatively. Postoperative pulmonary artery pressures were significantly lower than preoperative values. One child died 9 months postoperatively. CONCLUSIONS: Closure of a large VSD in children with elevated pulmonary vascular resistance can be performed with low morbidity and mortality when a flap valve double VSD patch is used.     

A 13CO2 breath test to assess the metabolism of triglyceride-rich lipoprotein remnants in mice

Five Eimeria species were reported from domestic rabbits (Oryctolagus cuniculus domesticus L.) caught from Jeddah, Saudi Arabia. According to their prevalences, they were: Eimeria perfarans (65%), E. magna (45%), E. stiedae (25%), E. exigua (20%) and E. piriformis (10%). 90% of the examined rabbits were positive and mixed infection with two or three Eimeria species was most frequent. E. stiedae, E. piriformis and E. exigua were identified and recorded for the first time from rabbits in Saudi Arabia and are considered as new locality or geographical distribution.