Randip R. Bindra

Changes in Interstitial Pressure and Cross-Sectional Area of the Cubital Tunnel and of the Ulnar Nerve with Flexion of the Elbow. An Experimental Study in Human Cadavera*

The purpose of this study was to determine the relationship between the ulnar nerve and the cubital tunnel during flexion of the elbow with use of magnetic resonance imaging and measurements of intraneural and extraneural interstitial pressure. Twenty specimens from human cadavera were studied with the elbow in positions of incremental flexion. With use of magnetic resonance imaging, cross-sectional images were made at each of three anatomical regions of the cubital tunnel: the medial epicondyle, deep to the cubital tunnel aponeurosis, and deep to the flexor carpi ulnaris muscle. The cross-sectional areas of the cubital tunnel and the ulnar nerve were calculated and compared for different positions of elbow flexion. Interstitial pressures were measured with use of ultrasonographic imaging to allow a minimally invasive method of placement of the pressure catheter, both within the cubital tunnel and four centimeters proximal to it, at 10-degree increments from 0 to 130 degrees of elbow flexion. As the elbow was moved from full extension to 135 degrees of flexion, the mean cross-sectional area of the three regions of the cubital tunnel decreased by 30, 39, and 41 per cent and the mean area of the ulnar nerve decreased by 33, 50, and 34 per cent. These changes were significant in all three regions of the cubital tunnel (p < 0.05). The greatest changes occurred in the region beneath the aponeurosis of the cubital tunnel with the elbow at 135 degrees of flexion. The mean intraneural pressure within the cubital tunnel was significantly higher than the mean extraneural pressure when the elbow was flexed 90, 100, 110, and 130 degrees (p < 0.05). With the elbow flexed 130 degrees, the mean intraneural pressure was 45 per cent higher than the mean extraneural pressure (p < 0.001). Similarly, with the elbow flexed 120 degrees or more, the mean intraneural pressure four centimeters proximal to the cubital tunnel was significantly higher than the mean extraneural pressure (p < 0.01). Relative to their lowest values, intraneural pressure increased at smaller angles of flexion than did extraneural pressure, both within the cubital tunnel and proximal to it. With the numbers available, we could not detect any significant difference in intraneural pressure measured, either at the level of the cubital tunnel or four centimeters proximal to it, after release of the aponeurotic roof of the cubital tunnel. CLINICAL RELEVANCE: These findings demonstrate that the cubital tunnel is a dynamic region morphologically. Both the cubital tunnel and the ulnar nerve change in area by as much as 50 per cent as the normal elbow is flexed and extended, with substantial flattening of the ulnar nerve but no evidence of direct, focal compression. These morphological findings corresponded well with measurements of interstitial pressure, which demonstrated an initial increase in intraneural pressure without a corresponding increase in extraneural pressure. This indicates that traction on the ulnar nerve is a major cause of increased intraneural pressure in association with flexion of the elbow.

Radiographic evaluation of osseous displacement following intra-articular fractures of the distal radius: Reliability of plain radiography versus computed tomography

This study evaluated the reliability of plain radiography versus computed tomography (CT) for the measurement of small (< 5 mm) intra-articular displacements of distal radius fracture fragments. The plain radiographs and CT scans of 19 acute intra-articular distal radius fractures were used by 5 independent observers, using 2 standardized techniques, to quantify incongruity of the articular surface in a blinded and randomized fashion. Repeat measurements were performed by the same observers 2-4 weeks later, allowing determination of intraclass correlation coefficients (ICC) as a measure of intraobserver and interobserver agreement. The average maximum gap displacement on plain radiographs was 2.1 mm (range, 0.0-15.0 mm, lateral view) and on CT images was 4.9 mm (range, 0.7-17.3 mm, axial view). The average maximum step displacement on plain radiographs was 0.9 mm (range, 0.0-6.4 mm, lateral view) and on CT images was 1.2 mm (range, 0.0-6.0 mm, sagittal view). More reproducible values determining step and gap displacement were obtained when the arc method of measurement was used on CT scans (ICC values, .69-.97) as compared to the longitudinal axis method for plain radiographs (ICC values, .30-.50). For measured displacements of 2 mm or more, our data demonstrated poor correlation between measurements made on CT images and those made on plain radiographs (gap or step displacement > 2 mm, K = 0.21; step displacement > 2 mm, K = 0.21). Thirty percent of measurements from plain radiographs significantly underestimated or overestimated displacement compared to CT scan measurements. From these data, we conclude that CT scanning data, using the arc method of measurement, are more reliable for quantifying articular surface incongruities of the distal radius than are plain radiography measurements.

Morphologic changes in the ulnar nerve at the elbow with flexion and extension: A magnetic resonance imaging study with 3-dimensional reconstruction****

We evaluated the morphology of the ulnar nerve and cubital tunnel with noninvasive magnetic resonance imaging (MRI). We used fresh human cadavers with the elbow in full extension, 90 degrees of flexion, and full flexion. For each elbow, 1-mm slices were imaged interpolated, and reconstructed into 3-dimensional data volumes, and then manually segmented before they were examined with sequential transverse sections, curved sections, and 3-dimensional images. The ulnar nerve follows a tortuous course in full extension, becomes progressively linear with incremental elbow flexion, shifts anteriorly in the cubital tunnel, and flattens against the medial epicondyle. The proximal and midportions of the cubital tunnel also change with flexion from round to elliptical. In addition, successive increases occur in the cross-sectional diameter of the mediolateral plane. The nerve is surrounded by fat throughout the cubital tunnel except adjacent to the medial epicondyle. These observations suggest that the ulnar nerve progressively stretch over the medial epicondyle occurs when the normal elbow is flexed. Direct compression areas of the ulnar nerve were not seen in our study of normal human elbows.

The use of routine wrist radiography in the evaluation of patients with carpal tunnel syndrome

The objective of this study was to evaluate the use of routine wrist radiography in the evaluation of patients with carpal tunnel syndrome (CTS). In the setting of a community-based hand surgery practice, we performed a retrospective review of charts and radiographs for 300 consecutive patients (447 wrists) meeting clinical and electrophysiologic criteria for CTS. Data on all patients included information obtained by the use of medical history questionnaires, physical examinations, nerve conduction studies, and radiographs of the wrist. Abnormalities were noted in 146 of 447 wrist radiographs (33%). Eighty-three (18.6%) had abnormalities that might have been implicated in the development of CTS, although these findings would not alter management. For only 2 of 447 wrists (0.4% of wrists; 0.6% of patients) were there radiographic findings of therapeutic significance. Radiographic charges were calculated to be

Epiphyseal Bar Resection and Fat Interposition for Clinodactyly

5,869 to

Management of nail-bed fracture-lacerations using a tension-band suture

20,115 for each finding of therapeutic significance. We conclude that wrist radiographs should not be performed routinely in patients with CTS, owing to the low yield of useful information.

Metacarpal Osteotomy for Correction of Acquired Phalangeal Rotational Deformity

Clinodactyly, the angulation of a digit in the anteroposterior plane, is often due to a longitudinal epiphyseal bracket on the radial side of the middle phalanx of the little finger. Treatment options include observation, osteotomy, and epiphyseal bar resection. Epiphyseal bar resection is a simple surgery that requires neither postoperative pin fixation nor immobilization. The most appropriate indications are in children 3 to 6 years old with radial deviation of at least 25 degrees. The procedure reliably diminishes the extent of deformity.

Late Reconstruction of Ulnar Nerve Palsy

Nail-bed lacerations are frequently encountered in the emergency room and, along with other fingertip injuries, constitute the most common type of hand injury. 1 Among the various mechanisms of injury, trapping the finger in a closing door is the most common, 2 accounting for 25% of these injuries. 3,4 The rigid nail plate itself remains intact but gets separated from the underlying proximal nail bed to a variable extent and may come to lie on the dorsum of the proximal nail fold. In approximately 50% of cases, the underlying distal phalanx is fractured, 5 resulting in a transverse laceration of the nail bed, which is displaced with the osseous fragments. In extreme instances, the fingertip is partially amputated, remaining attached by only a narrow bridge of palmar soft tissues. Adequate primary treatment is necessary to minimize subsequent nail deformity. 6 The recommended management of these injuries is reduction of the fracture followed by repair of the nail bed. The nail plate is replaced and the fracture is stabilized with Kirschner wires (K-wires). 7,8 I describe here a technique for obtaining stability of the fracture in such injuries without the use of K-wire fixation, using a dorsal tension-band suture.

Chondroblastoma-like chondroma of the hand: case report.

Symptomatic phalangeal rotation deformities require corrective osteotomy. Surgery at the phalangeal level is technically demanding and has a higher complication rate. We describe the surgical technique of metacarpal base osteotomy for rotation correction of the digit. This technique is simple, allows early rehabilitation, and has a lower complication rate.

Volar wedge grafting for scaphoid nonunion with collapse.

Ulnar nerve palsy results in significant loss of sensation and profound weakness, leading to a dysfunctional hand. Typical clinical findings include loss of key pinch, clawing, loss of normal flexion sequence of the digits, loss of the metacarpal arch, and abduction of the small finger. Further deficits in hand/wrist function are seen in high-level ulnar nerve palsy, including loss of ring- and small-finger distal interphalangeal flexion, decreased wrist flexion, and loss of dorsal sensory innervation. This article reviews the clinical findings seen in low and high ulnar nerve palsies, and reviews surgical options for correcting certain motor and sensory deficits.