Nerve entrapment as a cause of shoulder pain in the spinal cord injured patient

INTRODUCTION

Many people with chronic spinal cord injury (SCI) develop shoulder pain, which can adversely impact transfers and independence. Yet effective treatments remain elusive.

CASE PRESENTATION

This report presents two patients with tetraplegia who had long-standing shoulder pain. Our exam showed muscle weakness and point tenderness, suggestive of nerve entrapments of the radial and axillary nerves in the posterior shoulder. These nerves were surgically decompressed and post-operatively the patients' pain resolved.

DISCUSSION

Shoulder nerve entrapments are uncommon but SCI patients may be at more risk due to their unique upper extremity demands. SCI providers should consider proximal nerve entrapments as a possible cause of shoulder pain.

Diagnostic distribution of non-traumatic upper limb disorders: vibrotactile sense in the evaluation of structured examination for optimal diagnostic criteria

BACKGROUND

Upper limb disorders (ULDs) are common, and so are the difficulties in specific diagnoses of these disorders. Prior studies have shed light on the nerves in the diagnostic approach beside disorders related to muscles, tendons and joints (MCDs).

OBJECTIVE

The study aimed to compare the distribution of upper limb disorders, and the vibration perception threshold (VPT) in different diagnostic groups according to 1) A-criteria: the SALTSA consensus criteria, including MCDs and four peripheral neuropathies, and 2) B-criteria: including MCDs and 10 different neuropathy diagnoses--re-defined in an attempt to refine diagnostic criteria of peripheral neuropathy in respect of different MCDs; and further to discuss the impact of the presented criteria.

METHODS

161 patients--recruited from 21 general practitioners--were examined by the same examiner according to the two sets of diagnostic criteria. VPT measurements were conducted in all patients.

RESULTS

Three patients did not fulfill the criteria of any ULD diagnosis. A/B criteria were fulfilled for 181/183 upper limbs, respectively, out of which 29.3%/163.3% were neuropathy diagnoses alone, 23.8%/10.9% MCD alone, and 46.9%/25.7% were categorized as neuropathy in combination with MCD diagnoses. The overall agreement on presence of neuropathy was high (75%), but on focal level there was a large discrepancy. According to the A-criteria, patients with symptoms located at wrist and shoulder were primarily defined with wrist diagnoses, and only few had concomitant shoulder diagnoses. In contrast, the B-criteria primarily defined neuropathy located at the shoulder, often concomitantly with neuropathy of the radial and the median nerve at the elbow, but seldom at the wrist level. In MCDs defined by both sets of criteria--Rotator cuff syndrome and medial/lateral epicondylitis--the A-criteria defined more MCDs than the B-criteria, the B diagnoses typically constituted only a part of the A diagnoses and additionally defined neuropathy. The B-criteria showed more significant VPT findings than the A-criteria concerning the discrimination between limbs with and contralateral limbs without diagnoses as well as between diagnostic groups with and without neuropathy.

CONCLUSIONS

The VPT findings suggest the B-criteria to be superior to A-criteria for differentiating between patients with and without neuropathy. This study shows that neuropathy is extensive in ULDs when specific diagnostic criteria are used. Additionally it suggests the importance of a critical revision of the current diagnostic criteria of upper limb neuropathy, and the differential diagnoses concerning the MCDs. Management and prevention is highly dependent on correct diagnoses.

Diagnostic accuracy of the neurological upper limb examination I: inter-rater reproducibility of selected findings and patterns

BACKGROUND

We have previously assessed the reproducibility of manual testing of the strength in 14 individual upper limb muscles in patients with or without upper limb complaints. This investigation aimed at additionally studying sensory disturbances, the mechanosensitivity of nerve trunks, and the occurrence of physical findings in patterns which may potentially reflect a peripheral neuropathy. The reproducibility of this part of the neurological examination has never been reported.

METHODS

Two blinded examiners performed a semi-quantitative assessment of 82 upper limbs (strength in 14 individual muscles, sensibility in 7 homonymous territories, and mechanosensitivity of nerves at 10 locations). Based on the topography of nerves and their muscular and cutaneous innervation we defined 10 neurological patterns each suggesting a focal neuropathy. The individual findings and patterns identified by the two examiners were compared.

RESULTS

Strength, sensibility to touch, pain and vibration, and mechanosensitivity were predominantly assessed with moderate to very good reproducibility (median kappa-values 0.54, 0.69, 0.48, 0.58, and 0.53, respectively). The reproducibility of the defined patterns was fair to excellent (median correlation coefficient = 0.75) and the overall identification of limbs with/without pattern(s) was good (kappa = 0.75).

CONCLUSION

This first part of a study on diagnostic accuracy of a selective neurological examination has demonstrated a promising inter-rater reproducibility of individual neurological items and patterns. Generalization and clinical feasibility require further documentation: 1) Reproducibility in cohorts of other composition, 2) validity with comparison to currently applied standards, and 3) potential benefits that can be attained by the examination.

Pronator syndrome: a retrospective study of median nerve entrapment at the elbow in female machine milkers

Pronator syndrome (median nerve entrapment at the elbow) is a rare condition, but it is more common among women than men. A long-term retrospective follow-up study evaluating the outcome of surgical release of the median nerve for female machine milkers has never been carried out before, nor has a long-term study of non-treated female milkers with pronator syndrome. In the present study, two groups of machine milkers (surgical and non-surgical) were compared. The clinical examination focused on two parameters: focal tenderness and individual muscle strength. The results showed that the surgical group had no focal tenderness on palpation over the median nerve at the elbow and no selective weakness in the muscles examined, as compared to what was found before surgery. In the non-surgical group, focal tenderness was found in 12 out of 14, and 10 out of 14 showed the same weakness as in an earlier examination. While this study has limitations in sample size, surgical release of the median nerve at the elbow level, in cases of pronator syndrome, appears to provide an immediate as well as long-term return to normal strength of FPL and FDP II, along with a significant improvement in subjective status. In the non-surgical group, spontaneous improvement of the strength of FPL and FDP II was found in only four out of the 14 cases.

Upper extremity nerve involvement in Swedish female machine milkers

Entrapment of the median nerve in the proximal forearm, the so-called pronator syndrome, is considered a rather rare condition but it is four times more common in women than in men. In this study, 23 of 30 female machine milkers with symptoms in the forearm and hand were clinically diagnosed as having the pronator syndrome. The diagnosis of median nerve involvement was based on the clinical history and on physical examination by a hand surgeon. All 23 milkers complained of aching in the volar part of the forearm and had a sensation of numbness, tingling, and decreased muscle strength in their hands, mostly in the hands which usually were statically loaded with heavy equipment. Objectively, all had an experience of tenderness over the pronator teres muscle. Furthermore, they showed reduced muscle strength, especially in the following muscles: pronator teres (PT), flexor carpi radialis (FCR), flexor pollicis longus (FPL), and flexor digitorum profundus II (FDP II). To validate the manual muscle testing, Mannerfeldt's intrinsicmeter was used to quantify the clinically observed weakness. Eight of the 23 milkers with pronator syndrome were surgically released from neuropathy and were almost symptom-free at follow-up after six months. One patient had a slight sensation of numbness and had to be given surgical carpal tunnel release later on. The external exposure of the arm during the application of the milking cluster probably causes muscle and fascial tensions that induce compression of the nerve. Further studies are needed to establish the level of the internal exposure.

Experimental osteonecrosis of the lunate. Revascularization may cause collapse

Is lunate collapse in Kienböck's disease a consequence of spontaneous revascularization, leading to focal osteolysis? A literature review of osteonecrosis in other locations such as the femoral head and bone allografts showed clearly that the loss of mechanical integrity is due to cellular processes which follow the spontaneous restoration of blood supply. We found no evidence in the literature that the lunate has been shown to be avascular at the time of collapse. On the contrary, increased osteoclastic activity has been reported. We excised and reimplanted the lunate in two monkeys, and found spontaneous revascularization, leading to increased osteoblastic activity. Other parts of the bone were destroyed by osteoclasts, leading to collapse. This histological example suggests that it may be possible to make an analogy with osteonecrosis in other locations. Thus, changes on plain radiography may indicate that the bone is revascularized spontaneously. Before performing operative revascularization of the lunate, one should consider that revascularization is a probable cause for collapse.

Distal radius fracture and the distal radioulnar joint--anatomical considerations

The ulna represents the non-rotating, stable and weightbearing part of the forearm around which the radius rotates in pronation and supination. The distal radioulnar joint is the distal half of an articulation, the proximal half of which is the proximal radioulnar joint. In spite of the distance between the two, the distal and proximal radioulnar joints together form a bi-condylar joint, the "forearm joint", with the axis of rotation running from the centre of the radial head out distally into the interosseous space towards the centre of the ulnar head. The end of the radius together with the hand and what is held in the hand will rest against the stable, immobile ulnar head, which acts as the keystone of the wrist. Mobility and stability of the distal radioulnar joint is accomplished by the combined action between fully congruent articulating surfaces and intact radioulnar ligaments. Following a distal radius fracture, the semilunar notch of the radius will no longer be congruent to the ulnar head due to the displacement of the distal fracture fragment of the radius into either dorsal angulation, radial angulation, or both. The stabilizing ligaments will tear. Any posttraumatic disabling dysfunction of the distal radioulnar joint should accordingly be treated by a corrective osteotomy of the radius at the fracture site in order to achieve full congruity between the semilunar notch and the ulnar head. Resection of the ulnar head deprives the wrist its keystone and should therefore be avoided.

The distal radioulnar joint in relation to the whole forearm

The functional anatomy of the distal radioulnar joint was studied in relation to the whole forearm, using three fresh-frozen, above-elbow amputation specimens. The specimens demonstrate how the proximal and distal radioulnar joints together form a bicondylar joint of special character. The proximal "condyle," the radial head, rotates axially, whereas the distal "condyle," the ulnar head, is fixed with respect to rotation. The ordinary articulation of a bicondylar joint (pure axial rotation) is thereby changed into pronation-supination. Axial rotation is preserved proximally, while distally the radius swings around the ulnar head. The mobile radius is distally attached to the stable ulnar head by the dorsal and volar radioulnar ligaments, the dorsal ligament being tight for stabilization in supination and the volar ligament being tight in pronation. The ulnar head also serves as a keystone, carrying the load of the radius. Removal of the ulnar head allows the radius to "fall in" towards the ulna, with narrowing of the interosseous space.

Hyperpressure in the trapezius muscle associated with fibrosis

The intramuscular pressure at rest and during load in 25 symptomatic trapezius muscles was found to be higher than in 32 asymptomatic muscles. Operative findings in 4 patients revealed dense fibrosis around the muscle, including the accessory nerve, which might explain the increased intramuscular pressure. Fibrotic tissue release resulted in the relief of symptoms and normalized pressure both at rest and during load. We believe trapezius fibrosis may be a new entity to include in the neck-shoulder syndrome.

The correlation between work environment and the occurrence of cervicobrachial symptoms

The correlation between symptoms from the neck and upper extremities and some individual and work-related factors was analyzed in 2814 industrial workers. Physical stress by type of job was the factor most strongly correlated with ongoing cervicobrachial symptoms. Symptoms from the neck and upper extremities were twice as common in workers who used vibrating hand tools. Mental stress at the onset of the symptoms was associated with an increased prevalence of trapezius myalgia and with lateral humeral epicondylitis and "radial tunnel syndrome" in the dominant arm. Women had about double the rate of cervicobrachial symptoms as did men. Short stature increased the rate of symptoms from the neck, shoulders, and hands as did overweight. Playing of racquet sports decreased the risk of symptoms from the neck and hands.

Sickness absenteeism in an engineering industry--an analysis with special reference to absence for neck and upper extremity symptoms

Neck and upper extremity symptoms (NES) are reported to increase among industrial workers. In order to quantify sickness absenteeism and relate it to some factors a questionnaire study was performed among 2,814 workers occupied at a Swedish engineering industry. Questions pertaining to age, sex, worker category, work with vibrating handtools, type of job and smoking habits were analyzed and correlated to sickness absenteeism for the previous year (1983). We found that the average days lost for personal illness was 17.2 days; 16.2 for men and 23.5 days for women. Ninety-four persons, 77 men and 17 women comprising 3.0% of all employees were sicklisted for NES corresponding to 3.3% of total sickness time lost. Blue-collar workers were sicklisted for NES five times more often than white collar workers and women in type 3 jobs (high NE stress), twice that of men occupied in the same type of job. Smokers had significantly higher absenteeism than non-smokers for any reason studied including NES. The study indicated a high prevalence of present NES problems (23%) but also that NES as a cause of leave of absence was relatively rare (3%).

The distal radioulnar joint

Reconstructive surgery of the distal radioulnar joint should be considered for those in the age range of 20 to 50 years, particularly in those patients having sustained a high-energy injury and in cases where there is a great demand on the wrist joint for heavy work and sports activities. Meticulous preoperative planning in terms of correct clinical and radiologic evaluation and strict adherence to restoration of the joint congruency and restoration of ligament function are most important in obtaining reliable, long-term results in the vast majority of patients.

Radiologic examination and measurement of the wrist and distal radio-ulnar joint. New aspects

Following fractures of the distal radius, a relatively high incidence of complications is caused by malalignment in the distal radio-ulnar (DRU) joint; recent anatomic and clinical investigations have shown congruity of that joint to be of significant importance for restoring the function of the wrist. The radius forms a moderately arched bone, which moves around the ulna in pronation and supination. Biomechanically, the ulna may be regarded as the pillar around which the radius moves. In an anatomic investigation of 5 arm specimens, we have shown that the maximum cartilage contact in the DRU joint between the ulnar head and the distal radius occurs in the neutral rotation position. A proposed routine examination method of the wrist and forearm includes a true antero-posterior and a lateral projection of the radius and the ulna, performed with the forearm and wrist in a neutral rotation, a neutral wrist deviation and with the elbow angled 90 degrees. Such an examination implies a standardized and reproducible method. In a radioanatomic investigation, a series of 50 healthy wrists and forearms were examined. A simple measuring technique is presented, applicable to the DRU joint and wrist favouring the ulna as the bone through which a reproducible long axis of the forearm/wrist may be drawn. It is suggested that the length of the radius should be judged relative to the ulna. Ulnar head inclination and radio-ulnar angle are new concepts, being major characteristics of the DRU joint. These angles of the right and left wrist were equal and no difference was found between the sexes. Minor alterations of the distal radius may be revealed when estimating these angles.

Metacarpophalangeal joint replacement with osseointegrated endoprostheses

A new type of endoprosthesis for reconstruction of the metacarpophalangeal (MCP) joint has been tested. The novel arthroplasty consists of a joint mechanism with two screw-shaped fixtures for bone anchorage. These fixtures, of commercially pure titanium, are gently screwed into the anchoring bone on each side of the diseased joint, the aim being to achieve osseointegration, i.e. a direct contact between implant and bone without interposed soft tissue layers. The hand was immobilized in a dorsal splint for 8-10 days post-operatively after which a carefully controlled mobilization program was initiated. In principle, the titanium fixtures, the surgical technique and the primary immobilization represent an approach similar to that previously used in various reconstruction procedures of the jaw. This paper describes 5 case histories of reconstructions required because of osteoarthrosis in a single MCP joint. Prior to the operation, all patients suffered from severe problems resulting from their arthrotic joints and they had not been able to work for several months. After surgery they were evaluated by a clinical assessment program and X-rays were taken at various times of follow-up. As well as visual inspection all radiograms were subjected to densitometry by means of a computer-based image-analysis system in order to provide information on the development of bone density in the bone-to implant interface region. From a functional point of view the treatment with osseointegrated prostheses must be regarded as being successful. All patients were able to go back to their original work and their hands had a satisfactory range of movement and grip strength with no signs of impaired function on longer follow-up time. Clinical problems were one re-operation, one case of implant fracture and one case requiring exchange of the joint mechanism. The computer-assisted evaluation of the radiograms revealed the presence of calcified tissue in many sections where the naked eye was not capable of differentiating any bone. In conclusion, it seems possible to establish osseointegration of MCP-endoprostheses in the arthrotic human joint in complicated cases which were regarded as contraindicated for any other joint arthroplasty.

The distal radio ulnar joint. The influence of geometry and ligament on simulated Colles' fracture. An experimental study

In five fresh frozen arm specimens Colles' fracture was simulated by a dorsal wedge osteotomy of the distal radius. A spring load was applied to the cortex of the distal radius fragment exerting a constant traction force in proximal direction. The distal radius fragment showed minimal dorsal angulation as the forearm was positioned in neutral or pronation, assuming the distal radio ulnar joint including its radio ulnar ligament was kept intact. As the forearm was moved into supination the distal fragment angulated dorsally to close the dorsal open gap in spite of the ligament being intact. When the radio ulnar ligament was detached the stability was however lost in any forearm position. The result supports the concept of immobilizing a satisfactorily reduced Colles' fracture in neutral position, possibly in slight pronation but never in supination.

Corrective osteotomy of malunited fractures of the distal end of the radius

Thirty-nine patients with painful impaired forearm rotation and reduced grip strength after malunited fracture of the distal radius were treated with corrective osteotomy of the distal radius, bone grafting and internal fixation and followed for an average of 1.5 years. All patients stated that they were improved by the procedure. At follow-up 36 patients were graded as excellent or good, implying no pain, moderate limitation of motion and grip strength not less than 70% of the uninjured hand. Two patients were graded as fair and one as poor. It is concluded that surgical correction of the deformity is a good procedure when treating disabilities in the distal radio ulnar joint following malunited fractures of the distal end of the radius.

Anatomical studies on the geometry and stability of the distal radio ulnar joint

In fresh-frozen amputated- and cadaver arm specimens the anatomy and stability of the distal radio ulnar joint were investigated. The articulating surface of the sigmoid notch of the radius and the corresponding surface of the ulnar head facing the sigmoid notch were studied in transverse cryo sections. In each specimen the radius of the curvature of the sigmoid notch was 4-7 mm larger than that of the ulnar head and consequently pronation and supination are combined rotation-sliding movement in the distal radio ulnar joint. The radio ulnar ligament consists of a dorsal and a volar fibrous part, broadly attached to the distal rim of the sigmoid notch and converging towards the fovea of the ulnar head. The cartilaginous disc is centrally located between these fibrous strands. In neutral position the articulating surface of the sigmoid notch is optimally covering the articulating surface of the ulnar head. This contact area is gradually diminished during pronation-supination until only a marginal contact remains at the end of each movement. The distal radius is kept stable in pronation by the volar part and in supination by the dorsal part of the radio ulnar ligament.

Metacarpophalangeal joint implants. III. Roentgenographic study of the in vivo function

With tomographic examination of the metacarpophalangeal joint in the straight lateral projection with maximum active extension and flexion, performed after the implantation of 42 Swanson and 41 Niebauer finger joint implants, it was possible to study the in vivo function of these implants. A method was devised to determine the position of the proximal phalanx in relation to the metacarpal bone in the plane of flexion. This was correlated to the ideal position of the proximal phalanx as determined for each of the implants in experimental studies and defined only by the implant axis of rotation. A displacement of the phalanx in the proximal and volar direction was found. Usually, this was more pronounced with fracture of the implant, and could be about 7-8 mm in each direction. The hinge of the Niebauer implant was found to bend significantly less than expected, indicating movements taking place in other parts of the implant. The two blocks of the midsection were found to move in relation to the adjacent bones. Indicating an insufficient intramedullary fixation of the stems, these findings explained why cortical erosions appeared at the sites where the stems were in close contact with the bone: dorsally in the metacarpal bone and volarly in the proximal phalanx.

Metacarpophalangeal joint implants. I. Roentgenographic study on the silastic finger joint implant, swanson design

A roentgenographic study was carried out on 104 Silastic Finger Joint Implants, Swanson design. Sixty-two of the implants were examined in the anterio-posterior-projection (AP) from 4 months to 5 1/2 years postoperatively, a total of 116 examinations. Forty-two implants were examined in the AP-projection and in the lateral projection by tomography in maximum active extension and flexion from 9 days to 42 months postoperatively, a total of 110 examinations. Stem fractures were found in 11/104 implants: two of these preceded by a laceration of the implant surface visualized by tomography. Fragmentation of the midsection was found in 14/104 implants. Cortical erosion was seen radially in the phalanx and the metacarpal bone in some joints showing ulnar deviation, predominantly MCP joints II and III. On the tomograms a cortical erosion dorsally in the metacarpal bone could be demonstrated. Particularly around the distal stem was found an intramedullary bone lamella, varying in distance from the stem as well as in density and regularity. Bone resorption was found at the site where the midsection bore on the metacarpal bone and the proximal phalanx, resulting in a migration of the implant in a proximal and/or distal direction. The migration of the implant was evaluated on the tomograms with maximum active extension and classified into 4 Grades. Concomitant with the migration in the proximal direction a bony spur developed volarly at the resected end of the metacarpal bone, also seen in the AP-projection. The degree of maximum joint flexion was measured on the tomograms by drawing a line along the dorsal contour of each bone. In some cases flexion was found to decrease as a consequence of implant migration in the distal direction or the development of a bony spur. In several cases the range of flexion was maintained by gliding of the stems, particularly the distal one.

Metacarpophalangeal joint implants. II. Roentgenographic study of the Niebauer--Cutter Metacarpophalangeal Joint Prosthesis

A roentgenographic study was carried out on 41 Niebauer -- Cutter Metacarpophalangeal Joint Prosthesis from 1 to 36 months postoperatively, a total of 105 examinations. The examinations were performed in the AP-projection and in the lateral projection by tomography in maximum active extension and flexion. The tomographic examinations revealed implant damage of three kinds: cracking within the midsection; fragmentation of the midsection; fracture of the hinge. Cracking within the midsection was found in 8 implants between 6 and 12 months postoperatively and in 1 implant later than 12 months. Later examinations revealed fragmentation of the midsection in 2 implants previously showing cracks. Hinge fracture was observed in 22 implants. Implant damage was found in a total frequency of 26/41. Bone reaction was found on the tomograms in all the operated joints, and could not be evaluated on the AP-projections. A bony spur was found to develop on the metacarpal bone volarly at the site of the osteotomy in 35 joints. In 2 of these the bony spur reached the base of the proximal phalanx, causing anchylosis. Bone resorption was found in 23 joints, constantly dorsally in the metacarpal bone and volarly in the proximal phalanx. The mechanism of the implant damage is discussed with respect to the shearing forces in the joint and the two materials of differing elasticity constituting the implant. The bone reaction is discussed with respect to the intended fixation of the intramedullary stems.

Implants designed for finger joints. A roentgenorgraphic study and a study of implant wear and tear

Two types of flexible finger implants (one intramedullary movable, the Silastic Finger Joint Implant, Swanson design, and the other presumable intramedullary fixed, the Niebauer T-M Cutter Metacarpophalangeal Joint Prosthesis) were subjected to animal trials. Forty-four Swanson implants and 33 Niebauer implants were implanted in the knee joint of rabbits. Roentgenographic examinations were carried out immediately after surgery and then at monthly intervals. The joint was examined in the lateral projection in a flexed and in an extended position to obtain better information about the behaviour of the implant. The Swanson implant was assessed as being intramedullary movable. The Niebauer implant was found to bend within other parts than just the thin central part of the midsection as it is supposed to do. Intramedullary bone formation was seen along the distal stem of the Swanson implant. It developed in a very typical manner considered to be related to the motion of the stem. A similar phenomenon was seen along the distal stem of some of the Niebauer implants and was considered a sign of insufficient fixation of the stem. Cortical erosion and periosteal callus formation were found in the femur at the site at which the proximal stem of the Swanson implant was in direct contact with the bone. The implants were examined at autopsy both in situ and after removal. The Swanson implants showed consistently a wearing of the surface and a permanent deformation. Isolated cracks were seen in 8/44 implants, while fractures, either isolated or in combination with cracks and/or fragmentation, were seen in 22/44 implants. It was not possible to evaluate deformation of the Niebauer implants. Slight wearing was seen in 4/32 implants. Cracks, fragmentations and fractures were seen either isolated (except for the fragmentations) or in different combinations with no specific pattern in 25/32 implants. The combination of inelastic dacron fibres and elastic silicone rubber in one functional unit as in the Niebauer implant was considered the main cause of the damage.

Roentgenographic examination of the metacarpophalangeal joint

Roentgenographic examination of the metacarpophalangeal joints of the index, long, ring and the little fingers is carried out routinely in antero-posterior (AP) and oblique lateral projections, while pictures in the straight lateral projection of each joint are hard to evaluate because of overprojection of the other metacarpal bones and proximal phalanges. A technique was devised to examine each joint separately in the straingt lateral projection by means of tomography. This is presented together with the technique for examination of the joint in the AP-projection. The tomograms in the lateral projection were found to be more valuable when carried out in active maximal extension as well as flexion. The great advantage of this method, particularly in examinations for scientific evaluation, has been demonstrated in repeated postoperative studies of 98 metacarpophalangeal joints.