Biomedical subjects
Publications and source records attributed to P C Dell.
Systemic disease and metabolic imbalance may be associated with peripheral nerve focal compressive neuropathies. The nerve may be primarily involved, or symptoms may result from chronic tenosynovitis or synovitis. We review the more commonly occurring compressive neuropathies associated with underlying systemic disorders.
Trauma can lead to isolated or associated distal radioulnar joint disorders. Instability or incongruity of the joint frequently leads to pain, weakness, and limited forearm rotation. A knowledge of the anatomy and biomechanics is helpful to understand the pathology and to formulate a treatment protocol. This article reviews the surgical options that have been proposed to correct derangements of the distal radioulnar joint resulting from trauma.
Aseptic necrosis of the metacarpal head is extremely rare and has been described in association with systemic lupus erythematosus, steroid use, trauma, and other sites of bone infarction. The long metacarpal is the most commonly involved. The extrinsic and intrinsic vascular anatomy of the metacarpal is described in fifty metacarpal specimens. No definite conclusions can be drawn about anatomic variations in blood supply between the different metacarpals. However, in 35% of the specimens, a main arteriole in the distal epiphysis was absent, making these metacarpal heads solely dependent on small circumferential pericapsular arterioles. This group of metacarpals, when associated with other risk factors, such as trauma, systemic lupus erythematosus, or steroid use, may be at increased risk for the development of aseptic necrosis.
Eleven patients had elbow manipulation under general anesthesia to improve a dysfunctional range of motion. Six (55%) patients improved their motion, three (27%) patients had no significant change, and two (18%) patients lost motion. Type of injury, extremity dominance, previous surgical procedures, delay to manipulation, or use of postoperative steroid injections and continuous passive motion did not correlate with successful results. Two transient sensory ulnar neuropathies were the only complications and no heterotopic bone formation or exacerbation was observed. Manipulation under anesthesia should be considered in patients with a dysfunctional elbow range of motion after failure of well-supervised rehabilitation.
The collagen arrangement of the triangular fibrocartilage complex was studied in 20 fresh cadaver wrists by means of standard and polarized light microscopy and scanning electron microscopy. The collagen fibres in the articular disk are arranged in undulating sheets oriented at oblique angles to each other. The fibers of the radioulnar ligaments are oriented longitudinally from the radial origin to the ulnar insertion. The origin of the articular disk from the radius is characterized by thick fibers 1 to 2 mm in length radiating from the radius into the articular disk. Five specimens were also injected with india ink. The radioulnar ligaments and the peripheral 15% to 20% of the articular disk are well vascularized, whereas the central 80% of the articular disk is avascular.
Over the last 15 years, vascularized bone grafts have proved to be a valuable method of reconstructing skeletal defects in the extremities. Successful skeletal reconstruction has been reported following tumor resection, select traumatic skeletal defects, congenital pseudarthrosis, and both infected and uninfected skeletal nonunions unresponsive to conventional methodology. Incorporation of the graft into the recipient is not as dependent on an uninfected well-vascularized host as a conventional avascular autogenous graft is. Vascularized autografts are also capable of achieving union across large skeletal defects with fewer stress fractures than when avascular autografts are used to span a defect greater than 6 cm. With patency of the vascular anastomoses and union at both ends of the graft, hypertrophy of the segmental graft is not unusual. The overall success rate of ultimate bony union is approximately 80% and is mostly dependent on the recipient location. As discussed in this article, vascularized autografts are a salvage procedure to be used in reconstructing extremities in which conventional reconstructive techniques have failed or are not applicable.
Numerous fixation techniques have been described to obtain successful proximal interphalangeal (PIP) joint arthrodesis. By use of the Herbert screw for compression, 50 (98%) out of 51 PIP joints were fused within 6 weeks. Biomechanically, PIP joint arthrodeses using the Herbert screw in cadaver joints were comparable to tension band arthrodeses evaluated by three-point bending. Herbert screw arthrodesis of the PIP joint achieves a high fusion rate with minimal external protection provided certain technical details are followed.
Fractures of the hook of the hamate frequently fail to unite. In symptomatic nonunion, surgical excision of the hook has provided relief of pain in the few reported cases. In a survey of surgeons, 133 cases of excision of the hook to treat nonunion were reviewed retrospectively. The complication rate associated with excision is three percent. These complications, such as injury to the ulnar nerve or the superficial palmar arch and median nerve paresthesias secondary to retraction are due more to the surgical exposure than the actual excision.
Six patients who injured their wrists had radiographs documenting a dorsal, 5- to 10-mm oblong fragment of bone immediately proximal to the base of the fourth and/or fifth metacarpal bones. The fragment was seen on the pronation oblique and/or lateral projections, but not on the posteroanterior projection. The radiographic appearance of the fragment was remarkably similar in all cases. In the one patient in which it was performed, pluridirectional tomography demonstrated that the fragment originated from the dorsal surface of the hamate. Five of the six patients also had associated posterior dislocation of the fourth and/or fifth metacarpals. We conclude that this fragment represents a coronal fracture through the body of the hamate resulting from posterior dislocation or subluxation of the fourth and/or fifth metacarpal.
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An experimental method of approximating severed flexor tendons in zone II that allows immediate postoperative mobilization is described. The repair uses a nonabsorbable suture anchored into the severed tendon in zone III. This experimental repair was performed on one foot in each of 18 adult, white Leghorn chickens. The control side used the modified Kessler technique to repair the zone II laceration. The animals were prevented from weight-bearing activities but were allowed active motion of the foot for 5 to 6 weeks postoperatively. The results demonstrated a marked diminution in flexor tendon adhesions, with intrinsic tendon collagen formation serving to reconstitute tendon continuity on the experimental side. The breaking strengths of the two repair methods were equivalent. These results suggest that this method may allow primary repair of tendon injuries in zone II, with minimal formation of adhesions.
Forequarter amputation combined with chest wall resection may present a difficult closure problem. In a recent case, the defect was satisfactorily closed with a free flap from the amputated extremity, employing the entire soft tissue of the forearm.
We performed high-resolution CT scans on 30 wrists in 27 patients with either previous surgical intercarpal fusion or known or suspected scaphoid abnormalities. Most examinations used the same protocol: contiguous 1.5-mm axial sections parallel to the long axis of the body of the scaphoid, small reconstruction circle, and bone reconstruction algorithm. Fifteen patients were evaluated for union of previous surgical carpal fusions; eight patients were evaluated for healing of scaphoid fractures; and the other four patients had miscellaneous disorders, including a midcarpal dislocation with a scaphoid fracture. High-resolution CT clearly showed whether the carpal fusions were united. In addition, metallic fixation devices were easy to locate and did not significantly degrade image quality. Osseous union of healing scaphoid fractures was reliably assessed. We conclude that high-resolution CT of the wrist is a useful method for evaluating surgical carpal fusions and various disorders of the scaphoid.
Dislocations of the DRUJ, when diagnosed promptly, may be successfully treated by closed reduction and immobilization. Symptomatic tears of the TFCC may be decompressed by ulnar shortening with or without debridement of the tear. Several operations are available for the treatment of derangements of the DRUJ. The Lauenstein procedure maintains TFCC function and restores stable painful forearm rotation.
Resection arthroplasty of the trapezium with either Gelfoam (Upjohn Co., Kalamazoo, Michigan) or tendon interposition was performed in 28 thumbs. Postoperatively, all thumbs were stable and all patients noted diminished pain and improvement in strength. Adduction contracture and metacarpophalangeal joint hyperextension must be corrected at the time of surgery. Interposition arthroplasty of the trapeziometacarpal joint accomplishes the surgical objectives and obviates the need for an implant. Subsequently, the rare complication of silicone synovitis following implant surgery is avoided.
Palmar dislocation of the lunate is believed to be associated with either disruption of the scapholunate ligament or a fracture through the scaphoid--the two being mutually exclusive. A case of trans-scaphoid palmar lunate dislocation with associated complete disruption of the scapholunate ligament is reported.
A case of an elbow ganglion cyst with compression of the radial sensory nerve is presented. The mass was noted on the anterior-radial aspect of the elbow after exertional trauma. Symptoms resolved following surgical excision. There has been no recurrence at one year.
Unreduced lunate, perilunate, and transscaphoid perilunate dislocations present a difficult and challenging surgical problem. The authors feel that all efforts should be made to obtain a reduction of the old dislocation. They support a combined dorsal and palmar approach, open reduction, and internal fixation of scaphoid with a Herbert screw to obtain midcarpal stability. A carpal tunnel decompression should be performed if symptoms suggest median nerve entrapment. When the dislocation is unable to be reduced, the authors favor limited wrist arthrodesis or a proximal row carpectomy in the absence of significant arthritis.