Sai S. Ramasastry

The Critical Relationship Between Free Radicals and Degrees of Ischemia: Evidence for Tissue Intolerance of Marginal Perfusion

UNLABELLED Skin-flap ischemia has been associated with the presence of free radicals. In this study, two enzyme systems involved in free-radical metabolism were used to compare a distal skin flap to a skin graft. Forty-two rats were divided into several test groups. A 10 X 3 cm dorsal rat flap was used, and tissue biopsies for xanthine oxidase and malonyldialdehyde (MDA) were obtained 2.5, 5.5, and 8.5 cm from the base of the flap at the hours given. In group I (control), the flap was outlined but not elevated, and biopsies were obtained. In group II, the flap was elevated, and biopsies were obtained at 6 hours. In group III, the flap was elevated, the distal 4 X 3 cm was amputated and replaced as a full-thickness skin graft, and biopsies were obtained at 6 hours. In group IV, the flap was elevated, and biopsies were obtained at 12 hours. In group V, the flap was treated as in group III, and biopsies were obtained at 12 hours. In group VI, the flap was elevated, and biopsies were obtained at 24 hours. In group VII, the flap was treated as in group III, and biopsies were obtained at 24 hours. RESULTS Xanthine oxidase was significantly higher in all distal biopsies compared to proximal biopsies. Xanthine oxidase also increased with time. Malonyldialdehyde increased over time as well as with distance from the flap base. Distal flap biopsies at 24 hours had greatly increased levels of malonyldialdehyde compared to skin grafts (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Extensive and complex defects of the scalp, middle third of the face, and palate: the role of microsurgical reconstruction.

Twenty-one patients with gigantic defects of the scalp and middle third of the face and palate following excision of neglected or recurrent tumors, burns, and infections have undergone microsurgical reconstruction. Wide resection of the middle third of the face, orbit, and palate requires “complex” three-dimensional volume reconstruction, whereas extensive defects of the scalp and skull (exceeding 80 cm2) require coverage of the large surface area soft-tissue defect and the exposed brain and dura. The latissimus dorsi free-muscle flap and split-thickness skin graft have become our methods of choice for extensive scalp and skull defects. The latissimus dorsi musculocutaneous free flap is preferable for reconstruction of complex palatal and external skin and orbital defects of the middle third of the face. Microsurgical free-tissue transfer reliably frees the oncologic surgeon from the constraints imposed by conventional reconstructive techniques and may therefore allow improved curative or at least palliative resection of these extensive tumors.

Free radicals: basic concepts concerning their chemistry, pathophysiology, and relevance to plastic surgery

This paper is an attempt to present important concerns in the rapidly expanding field of free radicals to a plastic surgical audience. Mechanisms and a systematic approach to free-radical pathology are presented, with several illustrative areas discussed more deeply.

Deferoxamine increases skin flap survival: additional evidence of free radical involvement in ischaemic flap surgery

This study presents further evidence of free radical involvement in skin flap necrosis in a dorsal rat flap model. Rats receiving deferoxamine, a free radical scavenger and iron chelator had significantly less necrosis (p less than 0.001) than saline treated rats. In a separate experiment, tissue determinations for malonyldialdehyde (MDA) were consistent with the survival results in showing a significant decrease in MDA in all biopsy sites (p less than 0.05 or less), indicative of reduced lipoperoxidation in the deferoxamine treated rats.

Cranial base surgery. Results in 183 patients

ObjectiveTo learn about the effects of cranial base surgery.DesignCohort study with a mean follow-up of 30 months.SettingPopulation-based.PatientsA consecutive sample of 183 patients who underwent cranial base surgery; 118 patients had malignant skull base tumors, majority were previously treated; 50 had benign tumors, 9 patients had congenital malformations of the skull base; 3 patients had inflammatory lesions, and 3 had traumatic defects of the skull base.Main outcome measuresDisease-free interval and overall survival as well as rate of complications and functional statusInterventionCranial base surgery was followed by radiotherapy (in previously untreated patients).ResultsAfter completion of follow-up (30 months, mean), 30 (25.4%) patients had died of their malignant tumors and 8 (6.8%) had died of other causes. One patient (0.84%) was lost to follow-up. The overall cancer survival without regard to histologic type was 67% (63% with no evidence of disease). Among the patients who were treated for benign neoplasm 72% were NED at a mean 39 months of follow-up. The group of patients with congenital malformations, inflammatory, and traumatic lesions demonstrated successful correction of their pre-surgical problem with skull base surgery. One patient (invasive aspergillosis) died of disease. The overall surgical/medical mortality was 2%, complication rate was 33% and Karnofsky performance scale was improved or unchanged postoperatively in 83% of patients. The average duration of surgery, number of blood transfusions used and the length of the hospital stay was 10 hours, 3 units, and 15 days respectively.ConclusionsCranial base surgery is a valid surgical technique for cranial base afflictions. In this study it was found to be beneficial in controlling benign as well as malignant disease and be the treatment of choice in selected congenital malformations, trauma, and inflammatory lesions.

Hyperbaric oxygen therapy and free radical production: an experimental study in doxorubicin (Adriamycin) extravasation injuries

The role of hyperbaric oxygen (HBO) therapy in free radical-mediated tissue injury is not clear. HBO has been shown to enhance the antioxidative defense mechanisms in some animal studies, but HBO has also been reported to increase the production of oxygen free radicals. To investigate this controversy, we studied the effect of HBO in a doxorubicin (Adriamycin) extravasation model, because the cytotoxic activity of doxorubicin is partly related to its quinone structure, which leads to the formation of cytotoxic oxygen intermediates. Fifty-four Sprague-Dawley rats underwent injection of 0.3 ml doxorubicin solution (2 mg per milliliter) intradermally on both flanks as described by Rudolph and colleagues. Group I (N = 28) received HBO treatment (2 hours at 2 ATA) for 3 days prior to injection and 7 days postinjection. Group II (N = 26) received no HBO treatment. At 2, 3, and 5 weeks, the size of the ulcers and the surrounding area of alopecia in group I (+HBO) were significantly larger than in group II (-HBO): 112.2 mm2 vs. 42.8 mm2 (p < 0.01) and 1,132.2 mm2 vs. 364.8 mm2 (p < 0.005). Biochemical analysis of the biopsied skin ulcers, to measure the parameters of oxygen free radical production, indicated (similar) low levels of xanthine oxidase for both groups. However, significantly elevated levels of malonyldialdehyde (MDA), indirect evidence of free radical production, was observed in group I (+HBO) in comparison with group II (-HBO): 36.58 vs. 5.84 ng per minute per milligram protein (p ≤ 0.001), which might indicate free radical-induced cellular injury. It is concluded that in this animal study the cytotoxicity of doxorubicin is potentiated by HBO therapy. The elevated levels of MDA suggest a direct additive cytotoxic effect by increased membrane lipid peroxidation. HBO therapy, therefore, might be deleterious in the early (preulcer) stage of doxorubicin extravasation.

Free latissimus dorsi muscle transfer using an endoscopic technique

Endoscopic techniques in plastic surgery have involved aesthetic procedures such as facelift, breast augmentation, abdominoplasty, and placement of tissue expanders. Recently, endoscopic harvest of the donor tissue for free flap transfer has included the omentum, jejunum, latissimus dorsi muscle, and rectus abdominis muscle. Ten patients with a soft-tissue defect in the lower extremity were successfully reconstructed from December 1994 to October 1995 with a free muscle transfer after endoscopic harvest of the latissimus dorsi muscle. Nine patients were male and 1 patient was female. A 5− to 6-cm incision was initially made along the posterior axillary line, allowing direct identification of the thoracodorsal vascular pedicle. The latissimus dorsi muscle was dissected posteriorly until the limits of open dissection were reached, and then the dissection was continued under endoscopic visualization. The largest harvested muscle was 15 × 25 cm in size. Follow-up ranged from 6 to 15 months. We believe that plastic surgeons can take advantage of endoscopic techniques to obtain reliable and safe results, with smaller scars and reduced postoperative donor site morbidity such as pain and wound-healing problems. This technique may prove particularly applicable to women, children, and patients who are prone to hypertrophic scars.

Hyperbaric oxygen therapy: effect on middle ear and eustachian tube function.

Hyperbaric oxygen therapy (HBO) involves intermittent inhalation of 100% oxygen under a pressure greater than 1 atm. It is an important mode of adjuvant therapy for disease processes such as decompression sickness, osteomyelitis, carbon monoxide poisoning, and poorly healing wounds. Patients undergoing this therapy often complain of ear pain and/or fullness which can be transient or long standing. This prospective study objectively measured the changes in eustachian tube function before and after HBO treatment in 33 adult patients by the 9‐step inflation‐deflation test described by Bluestone. The results show 15 of the 33 patients (45%) had evidence of eustachian tube dysfunction after treatment was initiated. Of these, 15 (100%) developed the sensation of fullness, 13 (87%) developed serous otitis media, and 7 (47%) required tympanostomy tubes.

Microsurgery for macrodefects: Microvascular free-tissue transfer for massive defects of the head and neck

Despite defect location and the fear of creating complex massive defects, coverage of large areas of soft tissue loss, with or without exposed calvaria, dura, and brain, can be reconstructed reliably with microvascular free tissue transfer. This technique permits separation of the oronasopharynyx from the intracranial contents, coverage of dural grafts, restoration of composite tissue loss, and achievement of superior aesthetic results in a single stage. When choosing vascular anastomotic sites, free-flap transfer permits a greater latitude in flap orientation, tailoring, and inset than is possible when using fixed pedicled rotation flaps. When confronted with a deeply invasive or gigantic malignancy, a multidisciplinary team approach is optimal. The risk associated with sophisticated ablative and reconstructive operative procedures is justified when dealing with potentially curable lesions. The success of these extensive procedures is related not only to the functional result and the aesthetic appearance, but most importantly to the resultant quality of life they allow.

Postoperative abdominal wall defects with enterocutaneous fistulae.

BACKGROUND Abdominal wall dehiscence with an associated enterocutaneous fistula is a surgical complication with high morbidity and mortality. Management of the abdominal wall defect is complicated by the continued emergence of liquid bowel contents. PATIENTS AND METHODS Large abdominal wall wounds of 10 patients with postoperative abdominal wall dehiscence and active enterocutaneous fistulae were managed with early skin grafting directly onto the granulated abdominal viscera. RESULTS Skin graft take averaged 93 +/- 12%, and there were no perioperative complications related to the skin grafting procedure. Overall mortality was 1 out of 10 patients. Enterocutaneous fistula output did not prove overly injurious to the skin grafts. Wound care was simplified in all but 1 patient with fitting of an ostomy appliance. CONCLUSION Temporary abdominal wall wound closure with skin grafts improved patient comfort and simplified wound care in a staged reconstructive approach to this surgical complication.