Radiostereometric analysis of early implant migration – a valuable tool to ensure proper introduction of new implants

1 reviewed 24 patients after decompression for peroneal entrapment neuropathy; in 3 cases the lesion was bilateral. There were 15 males and 9 females; mean age 44 (12–72) years. The etiology was an operation around the knee in 12, a tibial fracture in 2, a slight compression in 1, an ankle sprain in 2, excessive climbing in 2, sitting in a cross-legged position in 4, and in 4 cases no reason was found. There was foot drop in 15 and ankle instability in 12 cases. The nerve was decompressed after an average period of 17 months (4 days–8 years). Immediate relief of symptoms was achieved in 14 cases, slower relief in 10, and in 3 cases there was no recovery, In peroneal neuropathy, decompression should be considered after 2 months without recovery and after 4 months when recovery is slow.     

Decompression for peroneal nerve entrapment

I reviewed 24 patients after decompression for peroneal entrapment neuropathy; in 3 cases the lesion was bilateral. There were 15 males and 9 females; mean age 44 (12-72) years. The etiology was an operation around the knee in 12, a tibial fracture in 2, a slight compression in 1, an ankle sprain in 2, excessive climbing in 2, sitting in a cross-legged position in 4, and in 4 cases no reason was found. There was foot drop in 15 and ankle instability in 12 cases. The nerve was decompressed after an average period of 17 months (4 days-8 years). Immediate relief of symptoms was achieved in 14 cases, slower relief in 10, and in 3 cases there was no recovery. In peroneal neuropathy, decompression should be considered after 2 months without recovery and after 4 months when recovery is slow.     

Loss of small fibers in entrapment neuropathy and their regeneration after surgical decompression in a rat model

The study was carried out to investigate the loss of small fibers during entrapment neuropathy and their regeneration after surgical decompression. Entrapment neuropathy was mimicked in a rat model by wrapping the right sciatic nerve of Sprague-Dawley rats with a silastic tube of 1.3 mm inner diameter. A sham operation was performed on the left side. Additional naive rats were used as controls. In the subgroup of rats that received surgical decompression, removal of the tube was performed six months later. Intra-epidermal nerve fiber density (IENFD) was quantified by measuring protein gene product 9.5-immunoreactive epidermal nerve fibers in bilateral hindpaws. The results showed progressive reduction of IENFD after 1, 3, and 6 months of nerve entrapment (e1m, e3m and e6m): naive rats, 20.04+/-2.26 (e1m), 19.39+/-2.38 (e3m), 20.45+/-2.40 (e6m); right side with entrapment, 12.12+/-2.12 (e1m), 6.27+/-1.02 (e3m), 1.83+/-0.48 (e6m); left side after sham procedure, 13.72+/-2.20 (e1m), 8.59+/-1.37 (e3m), 4.56+/-1.07 (e6m) fibers/mm. Small fiber deficit was present both on the side with the entrapment and the contralateral side that had undergone the sham procedure. Increased IENFD was found at 1 and 3 months post-decompression (d1m and d3m), but failed to return to that of the naive rats: naive rats, 20.38+/-2.24 (d1m), 18.94+/-2.24 (d3m); entrapment, 7.00+/-1.14 (d1m), 6.97+/-1.40 (d3m); sham, 6.41+/-1.16 (d1m), 9.92+/-1.64 (d3m) fibers/mm. These findings demonstrate progressive degeneration of small fibers during entrapment neuropathy and partial restoration of innervation after decompression. The results also imply that, in addition to the contralateral side, naive controls are mandatory in the study of small fiber loss in entrapment neuropathy.     

Blood flow in a chronic entrapment neuropathy model in the rabbit sciatic nerve

A model of chronic entrapment neuropathy in the rabbit sciatic nerve was developed to try to elucidate the pathogenesis of chronic nerve entrapment. A non-compressive Silastic cuff was wrapped around the nerve at the mid-thigh level in eight rabbits. A sham operation that only elevated the sciatic nerve was performed in seven control rabbits. Six months later, the blood flow in the cuffed and the control sciatic nerves was determined with intra-arterially injected microspheres. Blood flow was significantly reduced in the entrapped nerve, compared to control nerves, but only in the segment proximal to the cuff. After surgical release of the cuff, the blood flow significantly increased in the proximal segment. This suggested that decreased blood flow may occur, but not necessarily at the site of nerve entrapment. Nerve conduction velocity changes were also consistent with an entrapment neuropathy. However, there were no significant quantitative morphometric changes at the nerve entrapment site, that is, in myelin thickness/nerve diameter ratio, distribution of axon sizes, and mean nerve fiber diameter. This indicates that only a mild entrapment was created.     

Entrapment radiculopathy: Hypothesis that explains spinal nerve root disorders after spontaneous resorption of lumbar disc herniation

This paper presents ten cases of lumbar spinal nerve root disorder differing from ordinary lumbar disc herniation (LDH) in pathology. The lumbar spinal nerve roots of the ten patients were entrapped or anchored to the posterior longitudinal ligament (PLL), as in entrapment peripheral neuropathy, causing symptoms of radiculopathy similar to LDH. Regression or complete resorption of LDH has been frequently reported. The pathology of perineural conditions after spontaneous resorption, however, has not been expensively studied. We compared disc degeneration in these patients with degeneration in patients with ordinary LDH, based on magnetic resonance imaging (MRI). We also compared the clinical courses in the two groups. The affected discs of 106 patients with low back pain and sciatica, treated operatively for LDH from July 1989 to October 1994 were studied and graded by MRI to assess disc degeneration. Of these 106 patients, 10 exhibited lumbar spinal nerve adhesion to the PLL (entrapment radiculopathy) without herniation mass on myelogram, computed tomography (CT)-myelogram, and MRI. The disc degeneration in the 10 patients showing nerve root entrapment corresponded to that in the 96 patients with LDH. All ten patients had a similar clinical history of recurrent sciatica and low back pain after remission of the first onset, and good results were obtained after neurolysis with free fat grafting, performed to protect against perineural scar formation or adhesions. One patient was follow-up from onset to recurrence by MRI. The pathology “entrapment radiculopathy” may be present in some patients with LDH after spontaneous resorption. Careful follow-up is necessary, even when spontaneous resorption of LDH is recognized by MRI or CT.     

Peripheral neuropathy in burn patients

Neuropathy in burn patients is frequently overlooked. This study aimed at looking for neuropathies among burn patients. It included 55 burn patients, whether symptomatic or asymptomatic, with variable depths of burn at different stages. Their ages ranged from 8 to 55 years with a mean age of 23.6 ± 11.1 years. All patients were submitted to clinical examination, electromyographic and motor conduction velocities of burned and unburned limbs. Serum electrolyte, blood urea and creatinine were measured for all patients. Sixteen patients (29 per cent) had peripheral neuropathy. Only six had symptoms and signs of peripheral neuropathy. The most frequently diagnosed neuropathy in this study was mononeuritis multiplex in nine patients (56 per cent), then generalized distal axonal neuropathy in five patients (31 per cent) and entrapment neuropathy in two patients (13 per cent). In patients with mononcuritis, 29 nerves were affected, 24 nerves related to the site of the burn and five nerves were away from the site of the burn. All the entrapment neuropathy developed after wound healing. Age above 20 years, electric burns, burns involving full thickness of the skin and a surface area of more than 20 per cent were associated with a significantly higher prevalence of neuropathy. Other parameters were not found to be significant in the development of neuropathy.     

Endovascular repair of thoracic aortic lesions with the Zenith TX1 and TX2 thoracic grafts: intermediate-term results

PURPOSE: This prospective study was designed to assess the technical success and outcome after patients with thoracic aortic pathology at high risk for conventional therapy were treated with the Zenith TX1 and TX2 endovascular graft. METHODS: Between 2001 and 2004, patients at high risk for conventional surgical therapy presenting with chronic aortic dissections, thoracic aneurysms, or aortobronchial or aortoesophageal fistulas were treated with a single- or multiple-piece endovascular grafts. Surgical modification of proximal or distal fixation sites was performed when necessary to establish adequate regions for device landing zones. Follow-up studies included radiographic evaluation before discharge and at 1, 6, 12, and 24 months. Aortic morphologic characteristics were determined by using three-dimensional imaging studies and centerline of flow measurements. Statistical analyses were performed with Kaplan Meier analysis to assess survival, factors predictive of poor outcome, and morphologic changes, including sac shrinkage. RESULTS: A total of 100 patients (42% women) were treated, including 81 aneurysms, 15 aortic dissections (with aneurysms), 2 patients with fistulous connections (1 aortobronchial and 1 aortoesophageal), 1 subclavian artery aneurysm, and 1 aortic rupture. Mean follow-up and aneurysm size were 14 months and 62 mm, respectively. Most patients (55%) had undergone prior aortic aneurysm repair. Surgical modifications were required to create adequate implantation sites in 29% patients, including 14 elephant trunk/arch reconstructions, 18 carotid-subclavian bypasses, and 4 visceral vessel bypasses. Iliac conduits were required in 19 patients. Overall mortality was 17%, and aneurysm-related mortality was 14% at 1 year. Sac regression (>5 mm maximum diameter decrease) was observed in 52% and 56% at 12 and 24 months. Growth was noted in one patient (1.6%) at 12 months. Endoleaks were detected in eight patients (8.5%) at 30 days and three patients (6%) at 12 months. Secondary interventions were required in 15 patients. Migration (>10 mm) of the proximal or distal stent was noted in three patients (6%) (two proximal and one distal), none of which required treatment or resulted in an adverse event. CONCLUSIONS: Acceptable intermediate-term outcomes have been achieved in the treatment of high-risk patients in the setting of both favorable and challenging anatomic situations with these devices. The complexity of the patient population, in contrast to endovascular infrarenal repair, attests to the differences in the pathophysiology aortic disease in the anatomic beds.     

Double compression of the ulnar nerve at the elbow and at the wrist (double-crush syndrome). Case report and review of the literature

Double compression of a peripheral nerve is not rare in medical practice. This article describes an ulnar neuropathy along the elbow and the wrist segments with electro-diagnostic examination (EDX). The proximal compression was an ulnar entrapment at the olecranon-epitrochlear semi-canal; the distal one was after the canal of Guyon, due to an arthro-synovial cyst arising from the pisohamatum joint. There aren't analogous clinical reports in the literature.     

上肢神经非创伤性神经束扭转

目的讨论上肢神经非创伤性神经束扭转的发病机理、诊断和治疗结果。方法对5例上肢神经非创伤性神经束扭转进行神经松解术1例,神经切断直接缝合4例。分析其病史并对该病的发病、病程、检查发现及术中发现进行探讨。结果5例上肢神经非创伤性神经束扭转患者与上肢神经非创伤性神经卡压患者在临床表现、诊断上均有差异,手术治疗有效率为80%。结论上肢神经非创伤性神经束扭转是区别于上肢神经非创伤性神经卡压的另一类疾病。     

A case of extension loss of great toe due to peroneal nerve compression by an osteochondroma of the proximal fibula

The authors present a case of extension loss of great toe caused by entrapment neuropathy of a peroneal nerve due to an osteochondroma of the proximal fibula. Plain radiographs revealed no bony abnormality around the foot or ankle, but a sessile exophytic bony growth at the proximal fibula. A positive Tinel sign in this area led us to a suspicion of compressive neuropathy of the peroneal nerve, and a subsequent electrophysiologic study confirmed the entrapment neuropathy. The peroneal nerve was decompressed by excisional biopsy. At 3 months postoperatively, normal full extension of the great toe was completely restored. The current case deserves attention in that the only clinical manifestation of peroneal nerve entrapment neuropathy by the osteochondroma at the fibular neck was extension loss of great toe.     

Extracorporeal tubing in the roller pump raceway: physical changes and particulate generation

Plasticized polyvinyl chloride tubing is used as the blood conduit in the heart lung bypass circuit. The section in the roller pump undergoes rigorous compression. Fatigue leads to material changes in weight and length of the bulk material. Particles are released during normal pump operation. This study evaluates the time course of particle loss. Three segments of 1/2" ID tubing run in the raceway for 30-minute, 1-hour, or 2-hour. The fluid path of each segment includes an oxygenator; a castor oil blend was used for the prime. The 5 mL sample was acquired at 10 minute intervals. Raceway tubing segments were measured for a change in weight and length. The same procedure repeated with 1/4" ID and 3/8" ID tubing. All tubing increased at least 5 mm by the 2-hour trial. There were no remarkable changes in weight. Particles were measured for size and percent volume. Tubing with 1/2" ID performed most consistently for particle release during all trials. Particles were observed as small as 1 nm. Particles as large as 3 micron could be confirmed. For all tubing there was particle release by 30 minutes. Perfusionists must consider tubing inner diameter and wall thickness in choosing the pPVC for the raceway in order to minimize particulate emboli. This research suggests that 3/8" ID tubing produces spalls inconsistently compared to 2" ID tubing. Thinner wall thickness tubing also has the potential to limit spall formation.     

Chronic nerve compression--an experimental model in the rat

This study reports a rat model of chronic nerve compression. The sciatic nerves of adult male Sprague Dawley rats were bonded with 1-cm lengths of tubing with varying internal diameters. Histological and electrical studies as well as studies to assess the blood-nerve barrier function were carried out at one through six months. With marked compression of the sciatic nerve, profound electrical changes were noted as early as one month, and histological findings were those of degeneration and regeneration. In the rats with minimal compression, nerve conduction studies remained normal. The earliest findings were alterations in the blood-nerve barrier, followed by histological changes in the large myelinated fibers at the periphery of the fascicles and changes about the nodes of Ranvier. This model appears to be a valid one with which to study other aspects of both the pathophysiology and treatment of chronic nerve compression.     

Endoscopic approach to cubital tunnel syndrome

The cubital tunnel syndrome is one of the most common entrapment neuropathy of the upper limb. The ulnar nerve can be compressed in the oteofibrous tunnel by the bone structures, the Osborne's ligament, the fascia of the ulnar flexor muscle of the carpus or of the aponeurosis of the deep flexor of the fingers. Pressure values in the cubital tunnel >50 mm Hg induce blocking of intraneural circulation with electrodiagnostic modifications, clinical signs and histological changes including demyelinazion of the nerve proximal to the cubital tunnel. Surgery becomes essential in case of failure of conservative and physical therapy. Various surgical techniques have been described in the literature for the treatment of the ulnar neuropathy at the elbow. In this paper the authors report a new endoscopic technique for the treatment of ulnar nerve entrapment at the elbow which requires respect of specific electrodiagnostic and clinical criteria of inclusion. The restored joint active motion following elbow arthroscopy in osteoarthritis can induce or get worse a ulnar nerve neuropathy; endoscopy neurolysis is essential to remove perineural adherences and reduces the nerve stress. Immediate well-being of the patient, lesser invasiveness and minimum vascular complications are clear advantages of the endoscopic approach, while the treatment of the pathologies proximal and distal to the Struther's arcade is a limit of the technique.     

The incidence and natural history of thrombus in the portal vein following distal splenorenal shunt.

The incidence of thrombus formation in the portal vein following distal splenorenal shunt was 4% occlusive and 14% nonocclusive from 1974 to 1977, and 6% occlusive and 22% nonocclusive in 1980. The increased incidence was probably due to more aggressive ligation of collaterals on the portal vein. Ten patients with this complication were evaluated prospectively with clinical and biochemical parameters, angiography, and nutrient hepatic perfusion. In this group, one thrombus was occlusive immediately after operation, and nine were nonocclusive: eight of the latter resolved by six months, but one progressed to total thrombosis. There were no demonstrable adverse clinical or biochemical sequelae. Angiography showed continuing portal perfusion in the face of nonocclusive thrombus, but at six months there was increased collateral formation and significant (p less than 0.05) reduction in portal vein diameter, from 20 +/- 4 mm to 14 +/- 5 mm. Nutrient hepatic perfusion at six months, 896 +/- 257 ml/min, was not significantly different from that seen prior to operation, 848 +/- 92 ml/min. It is concluded that the natural history of nonocclusive portal vein thrombus after distal splenorenal shunt is resolution, and management should be expectant.     

Follow-up of intracranial aneurysms in autosomal-dominant polycystic kidney disease

BACKGROUND: Approximately 8% of autosomal-dominant polycystic kidney disease (ADPKD) patients have intracranial aneurysms. The risk of growth and rupture of those discovered by presymptomatic screening is key to the feasibility and success of a screening program. This study was initiated to ascertain this risk. METHODS: ADPKD patients were offered screening with magnetic resonance (MR) imaging that included three-dimensional time-of-flight MR angiographic and three-dimensional phase-contrast sequences. Patients with aneurysms were recommended periodic surveillance, initially at 6 months and yearly, and less frequently after demonstration of their stability. RESULTS: Twenty-two saccular and one fusiform aneurysms were detected at the initial screening in 21 patients from 19 families (seven men and 14 women, 47.9 +/- 10.6 years old). All the saccular aneurysms were small (mean diameter 3.5 mm, range 2.0 to 6.5 mm) and the majority (77%) in the anterior circulation. Two patients died from unrelated causes without further follow-up. One patient was lost to follow-up. A new 2 mm middle cerebral artery aneurysm developed in one patient. One aneurysm increased from a size of 4 mm to 5 mm after a follow-up of 105 months. No aneurysmal development or growth occurred in the remaining 16 patients. No aneurysmal rupture occurred during a mean imaging follow-up of 81 months and a mean clinical follow-up of 92 months. During the period of the study, two additional ADPKD patients, with three intracranial aneurysms detected elsewhere by presymptomatic MR angiographic screening, were referred for surgical treatment. The larger size of these aneurysms (10, 8, and 8 mm) probably reflects referral bias. CONCLUSION: Most intracranial aneurysms detected by presymptomatic screening in ADPKD patients are small and in the anterior circulation. The follow-up results do not suggest an increased risk for growth and rupture, compared to those of intracranial aneurysms in the general population. These data do not support widespread screening for intracranial aneurysms in the ADPKD population.     

Carpal tunnel syndrome: current concepts

Carpal tunnel syndrome (CTS) is a clinical syndrome manifested by characteristic signs and symptoms resulting from an entrapment neuropathy of the median nerve at the wrist. It is the most common compression neuropathy in the upper extremity. In this paper, the etiology and pathophysiology of CTS are reviewed, as well as the clinical examination and other tests that may be useful in establishing its diagnosis. A variety of surgical techniques have been espoused for treating CTS refractory to non-operative treatment and the proposed advantages and disadvantages of the new procedures are discussed. If the diagnosis is correct, then surgical results are reliably good.     

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.     

DEVELOPMENT OF SMALL DIAMETER INTRAMEDULLARY NAILS MADE FROM ISO 5832–9 STAINLESS STEEL

Background : In order to improve strength in small diameter intramedullary nails, a system was designed in which the implants were manufactured from 30% coldworked ISO 5832–9 stainless steel. Methods : Nail diameters were 9 and 10 mm for the femur, and 8 and 9 mm for the tibia. The nails were solid rods and the screws were partially threaded. Pre‐clinical bending yield tests established that the 8‐, 9‐ and 10‐mm diameter rods had strengths comparable, respectively, with 10‐, 12‐ and 14‐mm diameter Grosse–Kempf nails. Forty‐eight femoral and 98 tibial shaft acute fractures were treated with this system. Postoperatively, patients were allowed to gently bear weight as tolerated. Results : There was one broken nail, occurring 10 months after femoral nailing. There were six broken screws, occurring between 3 and 6 months postoperatively in two patients and after more than 6 months in four patients. The broken screws had no adverse clinical effect. Five patients required late bone grafting or exchange nailing, and 15 patients required dynamization. Conclusion : This design of small diameter locked intramedullary nails was strong enough to allow early weightbearing.     

Effect of the extent of spondylodesis on the status of the lumbar vertebrae after surgical treatment of idiopathic scoliosis

Fifty-five patients with primary thoracic dextral idiopathic scoliosis treated by the Harrington method were studied. Posterior spondylodesis involved 8-14 vertebrae. Immobilization by a plaster-of-Paris jacket after operation was employed for 7-11 months. The mean follow-up was 14 years and 8 months. The studies were based on the clinical, radiological, and photogramometric evaluation of patients before operation, at one year after operation, and at least 5 years after operation. Two groups of patients were considered: with spondylodesis involving 8-10 vertebrae (25 patients) and 11-13 vertebrae (29 patients). In the analyzed material, better compensated posture occurred in the patients with posterior spondylodesis of 8-10 vertebrae and in whom the lower distractor hook rested on the L1-L2 vertebral arches, and when biological maturity of the spine was medium or advanced, and the age at operation ranged from 14 to 18 years and 4 months.     

Late sciatic nerve entrapment following pelvic plate reconstruction in total hip arthroplasty

Delayed sciatic neuropathy due to pelvic reconstruction plate loosening following complex acetabular reconstruction in total hip arthroplasty seems not be have been previously reported. We identified a 79-year-old woman who developed progressive neurologic signs of entrapment 6 months following reconstruction of a pelvic discontinuity due to fracture nonunion caused by radiation necrosis. Magnetic resonance imaging of the lumbar spine was unrevealing and electromyography demonstrated a peripheral neurogenic process involving the sciatic nerve. Sciatic nerve exploration was done at 12 months after surgery finding a loose screw in the pelvic plate impinging the nerve. Substantial improvement in clinical symptoms resulted from removal and nerve release.