Prevention of spinal cord injury after transient aortic clamping with tissue factor pathway inhibitor.

BACKGROUND: Lower limb paralysis that occurs in 11% of patients after treatment of thoracic and thoracoabdominal aortic aneurysms is unpredictable and at present not preventable. The proposed cause for the neurologic changes is believed to be spinal cord ischemia combined with ischemia/reperfusion injury. Recombinant tissue factor pathway inhibitor (rTFPI), a multivalent Kunitz-type inhibitor that binds to tissue factor-VIIa complex, was evaluated. METHODS: The effectiveness of rTFPI as an agent to limit spinal cord ischemia/reperfusion injury was studied in a rabbit spinal cord made ischemic for 20 minutes. rTFPI or phosphate-buffered saline solution (control) was given in randomized blinded fashion at the onset and conclusion of ischemia. Animals underwent neurologic evaluation at 24 hours in a blinded fashion with a modified Tarlov Scale to rate the lower limb paralysis (score of 4 = normal function, score of 0 = complete paralysis). RESULTS: Seventy-five percent of the TFPI-treated animals had Tarlov scores of 3 to 4, whereas only 29% of the animals treated with phosphate-buffered saline solution had such scores (p < 0.0014). Spinal cord histologic findings correlated with the neurologic findings. CONCLUSIONS: We believe that TFPI has unique inhibitory properties that make it an effective agent in limiting postoperative paraplegia associated with spinal ischemia.

Radiographic features of hand and wrist arthroplasties.

The normal and abnormal radiographic appearances of various arthroplasties of the hand and wrist have been presented. It is hoped that increased familiarity with these procedures and their radiographic features will lead to more meaningful radiographic interpretations by consulting radiologists.

Radiographic features of hand and wrist surgery excluding arthroplasties.

The normal and abnormal radiographic appearances of various hand and wrist surgical procedures have been presented. It is hoped that increased familiarity with these procedures and their radiographic features will lead to more meaningful radiographic interpretations by consulting radiologists.

Plasma lidocaine levels during augmentation mammaplasty and suction-assisted lipectomy.

Many plastic surgical procedures are dependent on or aided by the use of local anesthetics. Drug toxicity, although uncommon, is the most feared complication of this technique. There are multiple factors that lead to varying drug levels. These include drug concentration, speed of injection, rate of degradation, total dosage, site of injection or application, rate of administration, and the adjunctive use of vasoconstrictors. This study evaluates the use of subcutaneously injected lidocaine in patients undergoing suction-assisted lipectomy and augmentation mammaplasty. Lidocaine in the concentration of 0.5% containing either 1:100,000 or 1:200,000 epinephrine was used in doses up to 500 mg. Serial lidocaine levels were then obtained up to 1 1/2 hours after injection utilizing two different assay techniques. Our findings demonstrate consistently nondectable serum lidocaine levels despite the use of doses in excess of recommended "safe" amounts. This suggests that under specific circumstances and with certain operative procedures, lidocaine dosing can be liberalized.

The relationship of retrobulbar hematomas to vision in cynomolgus monkeys.

An experimental model has been developed to measure the effect of retrobulbar hematomas on functional vision in cynomolgus monkeys. In this model, functional vision was quantitated using flashed evoked visual potentials in five monkeys following creation of retrobulbar hematomas. In one monkey used as a control, functional vision remained impaired for 180 minutes following induction of retinal ischemia by increased intraorbital pressure. In two monkeys in which increased intraorbital pressure was relieved by anterior chamber paracentesis following 15 minutes of retinal ischemia, flashed evoked visual potential promptly returned to baseline level. In two additional monkeys in which increased intraorbital pressure was relieved following 30 minutes of retinal ischemia, flashed evoked visual potentials improved but never returned to baseline levels. This study demonstrates the usefulness of flashed evoked visual potentials in measuring functional vision in cynomolgus monkeys. This experimental model should prove useful in evaluating the effects of increased intraorbital pressure on functional vision and the effect of intervention on impaired vision due to retrobulbar hematomas. Further studies with larger numbers of animals are needed to clarify these preliminary studies and document longer-term effects of retinal ischemia secondary to retrobulbar hematomas.

Heterotopic renal transplantation in the rat: an advanced microsurgical training exercise.

Microsurgical training programs have instructed trainees from many surgical specialties with the expansion of these techniques into all areas of clinical surgery and experimental research. Most programs employ the rat femoral vessel model in microsurgical training. A more complex and less frequently used model, the rat renal transplantation procedure, can be used for advanced training in microsurgical and microurological techniques and offers several advantages over other microsurgical models. In the heterotopic renal transplant model, the left kidney from a donor rat is transferred to the inguinofemoral region of a syngeneic recipient. The method of revascularization can be varied from end-to-end repairs of vessels of equal diameter to those of unequal diameter. In addition to the variety of possible vascular repairs, an advantage of this model over others is that the kidney graft can be harvested by a technician, thus reducing the time commitments of the trainee. This model is ideal for microsurgeons, immunologists, and urologists, since it affords the opportunity for developing technical skills while preparing an experimental model that can be used for further research. We describe the model, the operative techniques, and the variations one can employ in performing the vascular repairs.

Dermatofibrosarcoma protuberans of the toe.

Dermatofibrosarcoma protuberans is an unusual soft-tissue tumor with a propensity for local recurrence and occasional metastatic spread. Given its indolent course, it may be mistaken for atypical scarring or a keloid growth. Most lesions are trunkal or on the proximal extremities with digital lesions being extremely rare. There is only one previous reference of the tumor arising on a toe. Early diagnosis and prompt wide local resection of this entity are required to prevent a local recurrence, which would necessitate a wider, more debilitating resection. The management of a patient with a dermatofibrosarcoma protuberans of the second toe is presented along with a review of the literature.

Use of small-caliber polytetrafluoroethylene (Gore-Tex) grafts in microsurgical training.

We present the use of polytetrafluoroethylene (PTFE) graft material as a microsurgical training model that better simulates live vessel repairs. PTFE grafts have mechanical advantages over polyethylene or silicone tubing in that they better mimic the "feel" of an arterial vessel wall, thus allowing the student to perfect counterpressor maneuvers before attempting live vessel repairs. Saving the PTFE "repairs" for later comparison and study provides the student with positive feedback that is not possible with living models. This cost-effective model has helped to shorten our directed teaching program and has reduced the use of laboratory animals.

Complete ear replantation without venous anastomosis.

Traumatic amputation of the entire auricle is a rare occurrence. Management ideally consists of microvascular reconstruction of auricular arterial, venous, and nerve continuity. However, appropriately sized veins are often not available and venous drainage must be accomplished with leech therapy. In occasional cases where leeches are unavailable or cannot be made to attach, mechanical drainage and anticoagulation can give satisfactory drainage. The authors present a case of mechanical wick venous drainage of a complete ear replantation, resulting in virtually normal appearance and function of the ear. In addition, the ear regained normal touch and two-point sensibility, although the great auricular nerve had not been repaired.

Angled side wall microarteriotomy scissors: a new end-to-side microvascular anastomosis instrument.

Creation of a smooth side wall arteriotomy for an end-to-side microsurgical anastomosis can at times be difficult and time consuming. To facilitate this maneuver, a new end-to-side microarteriotomy scissor was designed for creation of recipient vessel openings from 0.5-2 mm in size. These new scissors and their recommended use are described.

Stenosing flexor tenosynovitis.

A review of 253 consecutive digits with stenosing flexor tenosynovitis was done to clarify the respective role of steroid injection and surgical release in the management of stenosing flexor tenosynovitis. Treatment selection was based on the patient's age and severity of presenting complaints. In patients aged 10 years or more, analysis showed no statistically significant difference between results with steroid injection and surgical release. Surgical treatment was associated with higher cost and more complications. Based on this review, we recommend up to three injections of 20 mg of triamcinolone into the digital flexor sheath as the initial management of nonlocking, stenosing flexor tenosynovitis in adults. Initial management by surgical release is reserved for children and patients with digits locked in flexion.

Presence of growth factors in palmar and plantar fibromatoses.

Palmar and plantar fibromatoses are disease processes in which the presence of certain growth factors has not been defined. Monoclonal antibodies against transforming growth factor-beta, epidermal growth factor, procollagen type 1, fibronectin, phosphotyrosine residues, and CD41 platelet antigen were used in standard immunoperoxidase staining to study 36 nodules and 24 cords obtained from patients with fibromatoses. The specimens were studied via light microscopy, and staining intensity was quantitated using a computer-enhanced video system. Transforming growth factor-beta staining paralleled procollagen I, fibronectin, and phosphotyrosine staining within the nodule (early stages) but not the cord (late stages) tissue. These factors showed significant increased staining in the early stage of fibromatosis when compared to the late stage. This study is a preliminary demonstration of the presence of transforming growth factor-beta in palmar and plantar fibromatoses.

Characteristics and management of flexor tendon graft disruption.

In order to define the proper management of patients with disruption of a flexor tendon graft, 220 consecutive flexor tendon grafts were reviewed. Patients were divided into two groups--those who did not require a silastic rod prior to tendon grafting (89 grafts) and those who did require a silastic rod prior to tendon grafting (131 grafts). The incidence of tendon graft disruption for these two groups was 1.1% and 7.6%, respectively. Based on an analysis of these 11 graft disruptions, a method of management was devised. The literature is reviewed regarding the incidence and method of management of disrupted flexor tendon grafts.

Management of scaphoid fractures: a review and update.

The scaphoid is the most commonly injured carpal bone. Almost half of all bony wrist injuries involve the scaphoid. Treatment is controversial and, when inadequate, can result in a painful nonunion or degenerative radiocarpal arthritis. Fracture of the scaphoid occurs most often in young adult men, with a peak incidence between the ages of 15 and 30 years. The scaphoid is less susceptible to fracture during the phase when it is mostly cartilaginous, thus making scaphoid fracture rare in childhood. In this article, we review current treatment of fracture of the scaphoid and examine controversial topics in its management.

Use of leeches in plastic and reconstructive surgery: a review.

Leeches possess properties that make them uniquely able to assist with venous compromised tissue. Their saliva contains an anticoagulant and a histamine-like vasodilator that promote local bleeding, a local anesthetic, and hyaluronidase that promotes the local spread of the other leech salivary secretions into the wound/bite. In addition, active pharyngeal peristalsis further promotes the egress of venous blood. Resurgence in the use of leeches has been stimulated by Upton in the United States and Mahaffey in Europe. Currently, leeches are used at many microsurgical centers to provide critical venous outflow for compromised tissue replantations and transfers that might otherwise be unsalvageable. As the use of leeches becomes more widespread, knowledge of leech biology and physiology is important. This review reports on Hirudo medicinalis, the species used most often medically in Europe and the United States.

Fluctuation in grip and pinch strength among normal subjects.

Grip and pinch strength testing are commonly used to evaluate hand strength for disability ratings and to assess responses to various forms of therapy. This study determined the variations in grip and pinch strength in normal individuals. Ninety-five healthy subjects--61 women and 34 men--were examined prospectively by use of a Jamar dynamometer and a Preston pinch gauge. Grip and pinch were measured in the morning and afternoon twice a week for 3 weeks, giving a total of 12 testing periods. Mean grip strength fluctuated between 5.1 and 8.4 kg, or between 19.2% and 23.7%. Mean lateral pinch strength fluctuated between 2.6 and 3.8 pounds, or between 13.8% and 17.6%. There were no differences between the morning and afternoon values. Grip and pinch strength fluctuate over time. Repeat testing is necessary to accurately assess hand strength. Grip and pinch strength do not vary from morning to afternoon.

Tissue factor pathway inhibitor protects the ischemic spinal cord.

Tissue factor pathway inhibitor (TFPI) is a novel agent that binds to tissue factor/VIIa complex and factor-Xa, thereby reducing the effect of tissue factor (TF) on inflammation and the extrinsic pathway of coagulation. We hypothesize that systemic treatment with TFPI may limit ischemia-reperfusion (IR) injury. Our experiment was designed to evaluate the effects of TFPI on IR in the spinal cord. Twenty-three adult New Zealand white rabbits had snare occlusion devices placed circumferentially around the aorta and tunneled to a subcutaneous position. Forty-eight hours later, in the fully awake state, the animals were treated with either TFPI (1 mg/kg bolus followed by a 1-hr infusion of 20 microgram/kg/min), or heparin (100 U/kg bolus) followed by a 1-hr infusion of 10 ml/kg/hr of PBS while controls received phosphate buffered saline (20 ml followed by a 1-hr infusion of 10 ml/kg/hr). The infrarenal aorta was occluded for 21 min in all groups via the snare device. Animals were observed for 3 days and neurologic recovery was graded by the Tarlov criteria. Results were evaluated as percent of animals with hindlimb recovery (Tarlov 3 and 4). At 24 hr postocclusion, 88% of the TFPI-treated animals had recovered neurologic function versus only 20% of heparin-treated animals and 10% of the phosphate buffered saline group (P=0.031 and 0.009, respectively). At 72 hr, 63% of the TFPI animals retained neurologic function versus 20% of heparin-treated animals and 10% of phosphate buffered saline-treated animals (P=0.032, TFPI versus phosphate buffered saline). The mechanism of action of TFPI is not completely understood, yet this drug may hold promise in the prevention of IR injury of the spinal cord.