Robert M. Szabo

Endoscopic release of the carpal tunnel: A randomized prospective multicenter study

A 10-center randomized prospective multicenter study of endoscopic release of the carpal tunnel was carried out. Surgery was performed with a new device for transecting the transverse carpal ligament while control hands were treated with conventional open surgery. There were 122 patients in the study; 25 had carpal tunnel surgery on both hands and 97 had surgery on one hand. Of the surgical procedures, 65 were in the control group and 82 were in the device group. The endoscopic device was coupled to a fiberoptic light and a video camera. A trigger-activated blade was used to incise the transverse carpal ligament. After surgery, the best predictors of return to work and to activities of daily living were strength and tenderness variables. For patients in the device group with one affected hand, the median time for return to work was 21 1/2 days less than that for the control group. Two patients treated with the endoscopic device required reoperation by open surgical decompression; only one of these had incomplete release with the device. Two patients in the device group experienced transient ulnar neurapraxia.

Increasing Incidence of Shoulder Arthroplasty in the United States

BACKGROUND The number of total shoulder arthroplasties performed in the United States increased slightly between 1990 and 2000. However, the incidence of shoulder arthroplasty in recent years has not been well described. The purpose of the present study was to examine recent trends in shoulder hemiarthroplasty and total shoulder arthroplasty along with the common reasons for these surgical procedures in the United States. METHODS We modeled the incidence of shoulder arthroplasty from 1993 to 2008 with use of the Nationwide Inpatient Sample. On the basis of hemiarthroplasty and total shoulder arthroplasty cases that were identified with use of surgical procedure codes, we conducted a design-based analysis to calculate national estimates. RESULTS While the annual number of hemiarthroplasties grew steadily, the number of total shoulder arthroplasties showed a discontinuous jump (p < 0.01) in 2004 and increased with a steeper linear slope (p < 0.01) since then. As a result, more total shoulder arthroplasties than hemiarthroplasties have been performed annually since 2006. Approximately 27,000 total shoulder arthroplasties and 20,000 hemiarthroplasties were performed in 2008. More than two-thirds of total shoulder arthroplasties were performed in adults with an age of sixty-five years or more. Osteoarthritis was the primary diagnosis for 43% of hemiarthroplasties and 77% of total shoulder arthroplasties in 2008, with fracture of the humerus as the next most common primary diagnosis leading to hemiarthroplasty. CONCLUSIONS The number of shoulder arthroplasties, particularly total shoulder arthroplasties, is growing faster than ever. The use of reverse total arthroplasty, which was approved by the United States Food and Drug Administration in November 2003, may be part of the reason for the greater increase in the number of total shoulder arthroplasties. A long-term follow-up study is warranted to evaluate total shoulder arthroplasty in terms of patient outcomes, safety, and implant longevity.

Sensibility testing in peripheral-nerve compression syndromes. An experimental study in humans.

Sensibility testing in peripheral-nerve compression syndromes was investigated in an experimental study in humans. Twelve volunteer subjects had controlled external compression of the median nerve at the carpal tunnel at a level of forty, fifty, sixty, and seventy millimeters of mercury. The subjects were then monitored for thirty to 240 minutes with four sensory tests: two-point discrimination, moving two-point discrimination, Semmes-Weinstein pressure monofilaments, and vibration. Sensory and motor conduction, subjective sensations, and motor strength were also continuously tested. The threshold tests (vibration and Semmes-Weinstein monofilaments testing) consistently reflected gradual decreases in nerve function in both subjective sensation and electrical testing, while the innervation density tests (two-point discrimination and moving two-point discrimination) remained normal until nearly all sensory conduction had ceased. Decreased muscle strength occurred late, and not until changes had already occurred in each of the sensory tests. Threshold tests of sensibility correlated accurately with symptoms of nerve compression and electrodiagnostic studies, and are being evaluated for clinical use in a variety of peripheral-nerve compression syndromes.

Severely comminuted distal radial fracture as an unsolved problem: Complications associated with external fixation and pins and plaster techniques

Seventy-six patients with severely comminuted distal radial fractures were treated at two institutions, of which the overwhelming majority were Frykman class VIII. Fifteen fractures were open. Thirty patients were seen at the University Hospital; 17 had pins and plaster and 13 had external fixation. Forty-six patients were seen at Kaiser Hospital; all had pins and plaster treatment. The complication rate for those with pins and plaster at the University Hospital was 53%; the complication for external fixation rate was 62%. The affiliated-hospital complication rate was 52%. All patients with ipsilateral forearm shaft and carpal fractures developed a nonunion of the carpal fracture. Few patients maintained anatomic reduction, and many had significant intra-articular malalignment. External fixation with threaded half pins did not obviate pin problems in our series. These methods may help manage severely comminuted distal radial fractures, but complications should be anticipated and alternative treatment considered, especially when ipsilateral carpal or forearm shaft fractures are present.

Sensibility testing in patients with carpal tunnel syndrome.

We evaluated the sensibility of the hand preoperatively and at intervals postoperatively in twenty-three hands of twenty patients with idiopathic carpal-tunnel syndrome who underwent carpal tunnel release. Tests of sensibility included the threshold tests (vibrometry, 256-cycles-per-second vibration, and Semmes-Weinstein monofilaments) and one innervation-density test (two-point discrimination). In addition the wrist-flexion test, nerve-percussion test, and tourniquet test were performed preoperatively. Only five of the twenty-three hands had abnormal two-point discrimination and each of these also had markedly abnormal threshold-test values. Nineteen of twenty-three hands preoperatively had decreased sensibility detected by both Semmes-Weinstein monofilament testing and vibrometry. Six weeks after carpal tunnel release, all of the hands demonstrated improvement on threshold testing, and 65 per cent had normal values.

Tissue pressure threshold for peripheral nerve viability

To investigate the pressure threshold for peripheral nerve dysfunction in compression syndromes (carpal tunnel and compartment syndromes), carpal canal pressure was elevated to 40, 50, 60, and 70 mm Hg in normal volunteers. Motor and sensory latencies and amplitudes of the median nerve were evaluated before compression, after 30-240 minutes of compression, and during the postcompression recovery phase. Although some functional loss occurred at 40 mm Hg, motor and sensory responses were completely blocked at a threshold tissue fluid pressure of 50 mm Hg, measured by the wick catheter. In one subject in whom diastolic blood pressure was significantly higher than in other subjects, the threshold pressure was raised slightly. The Semmes-Weinstein monofilament test and the 256-cycle vibratory test were more sensitive than two-point discrimination tests for evaluating peripheral nerve function in this compression model. These results indicate that between 40 mm Hg and 50 mm Hg there exists a critical pressure threshold at which peripheral nerve is acutely jeopardized. Compartment decompression may not be indicated when interstitial pressures are below this level.

Epidemiology of humerus fractures in the United States: nationwide emergency department sample, 2008

To evaluate the occurrence of emergency department (ED) visits due to humerus fractures in the US.

Displaced fractures of the scaphoid.

The scaphoid is the most commonly fractured carpal bone. The displaced fracture poses a particular surgical problem. While scaphoid fractures as a group show a 90%-95% union rate, those fractures with greater than 1 mm of displacement are associated with a 55% incidence of nonunion and a 50% rate of avascular necrosis. Displaced fractures that unite spontaneously do so only after prolonged immobilization and are associated with a greater incidence of painful malunion. Displaced scaphoid fractures that result in malunion or nonunion are more prone to develop late carpal osteoarthritis. The higher incidence of complications with the displaced scaphoid fracture suggests that an anatomic reduction is essential. If closed manipulation is unsuccessful, open reduction and internal fixation are indicated.

Imaging strategies in the evaluation of soft-tissue hemangiomas of the extremities: correlation of the findings of plain radiography, angiography, CT, MRI, and ultrasonography in 12 histologically proven cases

Twelve patients with the histologic diagnosis of soft-tissue hemangioma of the extremities (nine intramuscular, two subcutaneous, and one synovial) were evaluated in a retrospective study using plain film radiography (n = 12), angiography (n = 8), computed tomography (CT; n = 4), magnetic resonance imaging (MRI; n = 3), and ultrasonography (US; n = 2). In eight of nine intramuscular lesions, the plain film demonstration of phleboliths suggested the diagnosis, while the plain radiographs were normal in three. Angiograms showed the pathognomonic features of soft-tissue hemangioma in six patients. MRI was characteristic in all three patients: The lesion demonstrated intermediate signal intensity on T1-weighted spin echo images and extremely bright signal on T2-weighting. US showed a hypoechoic soft-tissue mass in one case and a mixed echo pattern in the other. In one case, a central echogenic focus with acoustic shadowing consistent with a calcified phlebolith was identified, and one lesion exhibited increased color flow and low resistance arterial Doppler signal. CT showed a nonspecific mass in one of four cases and a mass with phleboliths in three. If a deep hemangioma is suspected, we recommend initial imaging with plain radiography followed by MRI. US may be useful in confirming the presence of a mass in doubtful cases or if MRI is unavailable. CT offers no distinct advantage over the combined use of plain radiography and MRI. Although angiography demonstrated the pathognomonic features in all six deeply situated lesions, because of its invasiveness it should be reserved chiefly for those patients undergoing surgical resection.

Distal radioulnar joint instability.

The distal radioulnar joint is inherently unstable. Pathologic instability can be acute or chronic; it can be dorsal, palmar, or multidirectional; and it can result primarily from soft-tissue injury or osseous malunion. Recognition of the type and cause of instability is fundamental to provide effective treatment.