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Biomedical subjects

R M Pearl

Publications and source records attributed to R M Pearl.

At least 19 recordsLinked to original sources
PubMed1995

Improved technique for fascial sling reconstruction of severe congenital ptosis.

Fascial sling surgery for severe congenital ptosis yields superior results when the operative result is dynamic rather than merely suspensory. The sling itself is attached as in a tendon transfer solely to the frontalis muscle, minimizing adherence to the underlying periosteum and the overlying dermis. The sling is passed behind a pulley created by the superior transverse ligament so as to produce a more normal vector of pull. The dermis of the skin is attached to the sling to create a dynamic supratarsal crease. Postoperative retraining allows the patient to achieve more than one centimeter of levator function. These operative modifications make this procedure more closely parallel the normal eyelid dynamics and yield consistently good results for this difficult problem.

Adult↗
PubMed1994

Multiagent pharmacotherapy to enhance skin flap survival: lack of additive effect of nitroglycerin and allopurinol.

Pathological vasospasm and free radical production contribute to skin flap necrosis. This study was undertaken to determine if postoperative combination therapy with the vasodilator nitroglycerin and the anti-free radical agent allopurinol would result in an additive enhancement of skin flap survival in the rat model. Thirty-one Sprague-Dawley rats were randomized into four groups and two cranially based dorsal skin flaps were raised on each rat. Both surgeon and data collector were blinded to treatments and all agents were given postoperatively. Control rats demonstrated 51 +/- 7.4% skin flap survival. Mean flap survival was significantly increased in groups receiving single agent therapy with either transdermal nitroglycerin (63 +/- 12% survival, mean +/- 2 SEM, p < 0.05) or intravenous allopurinol (62 +/- 10% survival, p < 0.01). No additional survival was seen in rats receiving both agents, which displayed 61 +/- 13% survival (p < 0.05, compared with controls). This study provides the first well-controlled demonstration that postoperatively applied transdermal nitroglycerin significantly enhances skin flap survival and includes a discussion of reasons for lack of additive effect of these agents.

Administration, Cutaneous↗
PubMed1993

Extensor digiti minimi tendon transfer to prevent recurrent ulnar drift.

Thirty percent of patients with rheumatoid arthritis develop ulnar drift. Although numerous operations have been described, recurrence of the deformity is frequent. We recommend use of the extensor digiti minimi tendon transfer to prevent recurrent ulnar deviation. The tendon insertion is moved from a dorsal location to a dorsal-radial position. In this new location, the tendon produces both extension and radial deviation. Moreover, this transfer is maximally effective in extension when ulnar drift is greatest. We have used this transfer 28 times during the past 6 years. In evaluating patients more than 1 year after surgery, metacarpal phalangeal joint extension averaged 52 degrees and there was no evidence of recurrent ulnar drift of the little finger. The only problem was slight hyperextension of less than 5 degrees in approximately half of the patients. However, in no patient was this functionally a problem. We recommend the use of this tendon transfer in all patients with ulnar drift undergoing metacarpal phalangeal joint replacement for rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1992

Treatment of enophthalmos.

This article has focused on the prevention and treatment of enophthalmos. It has stressed that enophthalmos is both a common complication of orbital fracture and a complication that can be difficult to treat. The cause of these failures of primary and secondary treatment is failure to recognize that orbital fractures have two distinct patterns and that neither is secondary to the anterior orbital floor defect. The zygoma fracture is the more common fracture and the most frequent cause of late enophthalmos. When this bone fractures, it does so at its sutural attachments. It is essential to reposition it at a minimum of three locations to achieve correction in three dimensions. The key to adequate reduction is not only to identify the frontozygomatic and zygomaticomaxillary suture at the infraorbital rim, but also to examine the zygomaticomaxillary suture in the region of the anterior maxillary buttress. Frequently, reduction at the first two sutural areas still leaves persistent lateral rotation of the zygoma and marked intraorbital volumetric expansion behind the axis of the globe. Complete reduction at three points will prevent late enophthalmos. Reosteotomy with repositioning of the zygoma and bone grafting to restore proper orbital volume can correct secondary enophthalmos once it develops. True blow-out fractures do occur, but the cause of the enophthalmos is most commonly the concomitant medial wall fracture and the occasional posterior expansion. The key to treatment is proper diagnosis, which is dependent upon CT scanning. Following definition of the exact fracture spots, restoration of intraorbital volume and sealing of the defects are satisfactory to avoid enophthalmos.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomechanical Phenomena↗
PubMed1991

Treatment of exophthalmos.

Current procedures for Graves' exophthalmos fail to achieve complete correction. The standard orbital decompressions were therefore modified to maximize the degree of volumetric increase behind the axis of the globe. In 15 orbits, the preoperative exophthalmos averaged 9.5 mm, whereas the postoperative exophthalmos was 4.1 mm. Postoperative CT study demonstrated that the remaining posterior orbital wall, combined with the persistently increased intraocular muscle volume, blocked retrodisplacement of the globe, despite adequate total volumetric increase. The increased muscle volume varied from 2 to 5 cc. Despite this residual exophthalmos, the modified four-wall expansion provides excellent aesthetic results with visual improvement and resolution of chemosis and exposure keratitis.

Female↗
PubMed1991

Pathophysiology of cleft lip muscles following the initial surgical repair.

Muscle biopsy specimens taken from the upper lip and perialar area during the time of secondary lip revision and studied by histochemical techniques demonstrate persistent connective-tissue and muscle abnormalities even at a distance from the cleft margins. Some of these changes are consistent with surgically induced denervation-reinnervation of muscle groups in the surgical field. Increased amounts of connective tissue also were found, most likely secondary to the original deformity and the subsequent surgical procedures. Both these changes may be important factors in subsequent abnormal growth and development of the underlying midfacial structures. This study also demonstrated the resolution of previously noted mitochondrial abnormalities found in the primary cleft lip patient.

Adolescent↗
PubMed1990

The iliac crest cartilaginous cap.

Bone and cartilage grafts can be procured from the ilium either separately or as composite chondroosseous grafts when sufficient cartilage is present. The thickness and anatomy of this iliac cartilaginous cap was analyzed in relationship to age in 50 individuals. Histology was that of normal hyaline cartilage. The cartilage alone was more pliable with little memory when compared with auricular or septal cartilage. The cartilage/bone junction was very strong. Cartilage thickness ran from close to 1 cm at age 5 to a diminished zero at age 25.

Bone Transplantation↗
PubMed1989

Dermal thymus. A light microscopic and immunohistochemical study.

Two rare cases of distinctive thymic remnants occurring in the skin are described. The lesions were present at birth, and involved the side of the neck. One child had a complete cleft lip and palate. The other had multiple congenital anomalies consistent with a rare syndrome entitled branchio-oculo-facial syndrome. Microscopically, lobular foci were present in the dermis and consistent with both prethymic and thymic remnants. Immunohistochemical studies using antibodies to T cells and B cells showed a distribution similar to that seen in normal thymus. Dermal thymus appears to be a distinct entity and may be associated with other faciobranchial defects.

Abnormalities, Multiple↗
PubMed1989

A comparative analysis of the ability of five classes of pharmacological agents to augment skin flap survival in various models and species: an attempt to standardize skin flap research.

There is a myriad of research in the pharmacological manipulation of skin flap survival. However, skepticism exists as to whether any of these drugs is clinically useful. We evaluated the efficacy of five categories of agents in improving skin flap survival in five different rat flap models. Diltiazem, isoxsuprine hydrochloride, nitroglycerin, prazosin hydrochloride (two doses), and methyldopa were compared in a double-blind, randomized fashion. Their benefits were assessed in a musculocutaneous flap, axial flap, and three types of random flaps. The "best" drug was determined to be nitroglycerin. Its efficacy was verified in a primate model.

Animals↗
PubMed1989

Pathophysiology of cleft lip muscle.

Although attention has been focused for decades on the correction of cleft lip deformities, our knowledge about the etiology of such deformities has remained presumptive. Sixty-six muscle biopsy specimens from cleft lip infants were obtained at the time of primary closure. Histochemical stains, histographic analysis, and electron microscopy were performed. A nonneurogenic muscle atrophy was seen that varied in severity, with muscle fibers near the cleft being the most atrophic and disorganized. Muscle fibers stained with the modified Gomori trichrome technique also demonstrated "ragged red" fibers typical of a mitochondrial myopathy. Electron microscopy confirmed large accumulations of mitochondria distorting the fibrils. These mitochondria also were increased in size and densely packed with cristae. This study thus demonstrates that the muscles in cleft lip deformities are not normal. Instead, they reflect either myopathy in the facial mesenchymal mitochondrion or at least a delay in maturation. We hypothesize that some of the morphologic deformities associated with cleft lip may cause a failure of mesenchymal reinforcement of the facial processes at a critical time in development.

Cleft Lip↗
PubMed1989

A congenital orbital defect with periorbital-dural tissue adhesion.

This case demonstrates a previously unreported congenital orbital deformity. The patient was born with a unilateral exophthalmos. The etiology of the defect was demonstrated by CT scan as a convex bowing of the right superomedial orbital wall behind the axis of the eye. At surgery, this convexity was revealed to be a small bony defect through which the periorbital tissue and dura mater adhered. This sort of orbital deformity, although subtle, must be considered in the differential diagnosis of congenital unilateral exophthalmos.

Exophthalmos↗
PubMed1988

An approach to mandibular reconstruction.

Mandibular reconstruction requires the restitution of both form and function. Proper preoperative planning, vascularized bone grafts, rigid fixation, flexibility of donor site choices, and restoration of labial, buccal, and lingual sulci lead to optimal reconstruction. We have used this approach in 38 patients; bony survival resulted in 37 and primary union in 35. A main limiting factor exists with individuals who have lost extensive amounts of soft tissue and muscle at the time of tumor resection or trauma. Only by attention to details in the preoperative, intraoperative, and postoperative phases can the best functional and aesthetic results be achieved.

Adult↗