Microvascular decompression for hemifacial spasm

858

CURRENT LITERATURE

vascular supply to the scalp is provided principally by four paired vessels of the supraorbital, superficial temporal, posterior auricular, and occipital arteries. Small scalp lesions ( < 3.0 cm) can be closed primarily, usually after some undermining. If pericranium remains, a skin graft can be placed to be excised in the future after tissue expansion. Local scalp flaps are effective in covering full thickness scalp defects. The pectorals major, latissimus dorsi and trapezius flaps are the three distant flaps most frequently described for scalp repair. Free tissue transfer of fasciocutaneous flaps from the radial forearm have also been described. Calvarial reconstruction is usually accomplished with alloplastic materials (including acrylic [methylmethacrylate], and various metal sheets) or autogenous grafts of rib, calvarium, or ilium. Postextirpative, postradiation wounds can result from minor trauma and become infected or necrotic. In these cases only large rotation flaps or free tissue transfers are effective.-R.H. HAUG

staged advanced (stage III of IV) squamous cell carcinoma of the head and neck region were entered in a prospective study (protocol-RIH/841). The study was a regimen consisting of an induction phase of 4,500 cGy and two cycles of cisplatin followed by an eradicative phase of either radical surgery (group A, 27 patients) or radical radiotherapy (group B, 41 patients). Cisplatin and radiation therapy have been found to be synergistic and additive. Concomitant use of high-dose cisplatin (100/mg/m 2 every 3 weeks) showed superior complete responses. This study showed 83% response (complete response, 26%; partial response, 57%) to induction chemoradiotherapy using cisplatin. Although the overall survival was 32% (no improvement compared with historic controls), the subgroup with pathologic complete tumor clearance had improved survival of 5 8 % . - - W . G . BAST

Reprint requests to Dr Luce: Division of Plastic Surgery, Kentucky Clinic, Suite K454, 740 South Limestone, Lexington, Kentucky 40536-0284.

The Medical Management of Masseteric Hypertrophy With Botulinum Toxin Type A. Moore AP, Wood GD. Br J Oral Maxillofac Surg 32, 1994

Normal Transcutaneous Oxygen Pressure in Skin After Radiation Therapy for Cancer. Rudolph, Tripuranemi P, Koziol JA, et al. Cancer 74:3063, 1994

Hypertrophy of the masseter muscle may be due to congenital malformations or a host of nonorganic causes such as clenching. Prior treatment modalities for esthetic correction of this deformity included intraoral or extraoral debulking of the muscle. Botulinum toxin type A (BtA) is a protein produced by the bacterium Clostridium botulinum. Its exact mechanism of action is unknown. However, it is known to block release of acetylcholine to cause presynaptic neuromuscular blockade. Muscles become weak typically within 2 to 20 days and recover within 2 to 4 months. The technique used in this study was to inject 100 mouse units into the most bulky aspect of the muscle. A 200-unit dose was injected 2 weeks later. Results showed significant clinical reduction in muscle bulk which satisfied the study patient. Results have lasted greater than 6 months. Possible risks include dysphagia or build-up of antitoxin antibodies so that repeated injections are rendered less effective.--G.T. LYNAM

Changes in skin after radiation treatment for cancer have been reported for years. These changes, including atrophy, scarring, ulcers, and a decreased ability to heal have been linked to progressive worsening ischemia including both a decreased blood supply and a decreased amount of oxygen delivered to the local tissues. This study evaluated the transcutaneous oxygen pressure (TCPO2), which accurately effects skin oxygenation, in 100 patients with a history of previous radiation therapy for cancer. Measurements were made at control sites and compared with the site of previous radiation, in addition, measurements were made with the patients breathing ambient air and with oxygen via face mask at 6 L/min for 10 minutes. Measurements by sex, grade, age, and time since irradiation were compared. Study results showed that control TCPO2 measurements were significantly higher than irradiated sites with and without supplemental oxygen in men, and only with supplemental oxygen in women. Medium and severe grades of radiation damaged skin did not differ greatly from normal skin regarding tissue oxygenation with ambient air or with supplemental inspired oxygen. Another interesting finding was that TCPOz values in the cheek, temple, and especially mandible regions in normal nonirradiated patients were lower than corresponding values for extremities. These normal levels could be lower than 30 mm Hg. Although some groups had significantly lower values in the irradiated groups, overall in 88% of irradiated patients, TCPO2 was within the accepted normal range and responded appropriately to supplemental oxygenation, even with increasing time since irradiation.--E.D. CHAFrrz

Reprint requests to Dr Chougule: Department of Radiation Therapy, Rhode Island Hospital, Providence, RI 02903.

Reprint requests to Dr Moore: The Walton Centre for Neurology and Neurosurgery, Walton Hospital, Rice Lane, Liverpool; Wirral Hospitals Trust, Arrowe Park Hospital, Wirral.

Lingual Abscess. Redleaf MI. Ann Otol Rhinol Laryngol 103:986, 1994 Tongue abscesses are rare, but lingual cellulitis without pus formation is seen in immunocomprimised patients. A case of lingual abscess in a 48-year-old diabetic edentulous man was CT scanned to distinguish it from lingual cellulitis. A clinical distinction of the two conditions in edematous tongues is not easily made. CT scans of cellulitis is seen as attenuation of the affected areas' signal, while abscess is seen as a rim-enhancing lesion with a low density cavity. The treatment regimens differ.--G.H. SPERBER

Reprint requests to Dr Rudolph: Scripps Clinic and Research Foundation, MS115, 10666 North Torrey Pines Rd, La Jolla, CA 92037.

Reprint requests to Dr Redleaf: Department Otolaryngology--Head and Neck Surgery, University of Chicago Medical Center, 5841 S Maryland Ave MC 1035, Chicago, IL 60637.

Cisplatin as a Radiation Sensitizer in the Treatment of Advanced Head and Neck Cancers. Chougule PB, Suk S, et al, Cancer 74:1927, 1994

Microvascular Decompression for Hemifacial Spasm. Barker FG, Jannetta PJ, Bissonette DJ, et al. J Neurosurg 82:201, 1995

Between 1984 and 1990, a total of 68 patients with previously untreated, histologically confirmed, and clinically

Hemifacial spasm, although painless, is distressing to patients because the involuntary spasms are exacerbated by

CURRENT LITERATURE stress or anxiety. Since the 1960s there has been increasing concensus that hemifacial spasm is best relieved by repositioning arteries in contact with the facial nerve in its course through the posterior fossa. This study reports the results of 782 microvascular decompression procedures for hemifacial spasm in 703 patients, who were observed for up to 20 years (1972 to 1992). Within that group, 648 had not undergone prior intracranial procedures. The mean patient age was 52 years, 60% had spasms on the left side, 65% were female, and the mean duration of symptoms preoperatively was 7 years. The onset of symptoms was typical in 92% and atypical in 8%. An additional 57 patients who had undergone decompression elsewhere were analyzed as a separate group. Among patients who had not undergone previous decompression, 86% had excellent initial results from microvascular decompression, 5% were graded partial successes, and 9% were rated failures. At 10 years postoperatively, 84% of the patients had excellent results, and 9% were operative failures. If the initial operation failed to provide relief from spasm in the first week, immediate reoperation was recommended. Of 12 such patients, 11 underwent reoperation, and 10 had long-term excellent results. One patient remained a failure. Complications included one operative death, two brainstem infarctions, facial weakness (mostly in reoperations of previously operated cases), hearing loss, and CSF leaks. Of 195 patients observed for 10 to 20 years, only three had recurrence of spasm during the second postoperative decade. The use of drugs in treating the condition is largely based on small cases studies and appears to be universally useless. Preoperatively, 3 1% of these patients had been unsuccessfully treated with carbamazepine and 21% with phenytoin. Patients rarely noted any improvement of symptoms or relief from spasms with medications. Thirty-three patients had had injections of botulinum toxin and 19 had had alcohol injections intended to relieve the spasms, without success. The authors believe that this substantiates that microvascular decompression should remain the treatment of choice for most hemifacial spasm patients and has a reasonable operative morbidity rate of 0.4%.--R.E. ALEXANDER Reprint requests to Dr Jannetta: Presbyterian-University Hospital, Room B-400, 230 Lothrop St, Pittsburgh, PA 15213.

Adjuvant Therapy of Soft-Tissue Sarcomas. McGrath PC, Sloan DA, Kenady DE. Clin Plast Surg 22:21, 1995 Combination surgery and radiation therapy are currently the standard of care for the primary treatment of soft tissue carcinomas. Radiation my be used alone to palliate local, advanced, inoperable, recurrent, or metastatic disease. The use of preoperative radiation has the advantages of requiring smaller portholes than postoperative radiation, it decreases the risk of tumor implantation during surgery, and it allows for a more conservative resection. The disadvantages include a delay in definitive surgery and a risk of compromised healing. Postoperative radiation possesses the advantages of normal wound healing, more accurate pathologic staging and the psychological benefit of knowing that the tumor has been removed completely. The disadvantages include larger portholes, recurrence, and tumor regrowth during the period of waiting between surgery and radiation. Intraoperative brachytherapy provides immediate treatment rather than the 5- to 7-week course required for surgery and external beam radiation. For recurrences, additional radiation appears more effective if delivered before, rather than after the excision. Adjuvant chemotherapy should be directed toward those patients with the highest likehood of suffering distant relapse.

859 Adjuvant chemotherapy is still in the investigational phase, with the identification of new agents helping to better define the role of this therapy.--R.H. HAUG Reprint request to Dr McGrath: Department of Surgery, University of Kentucky Chandler Medical Center, 800 Rose St, Lexington, KY 40536-0084.

Oncologic Considerations in Nonmelanotic Skin Cancer. Luce EA. Clin Plast Surg 22:39, 1995 A thorough cognitive grasp of the available information on the behavior of nonmelanotic skin and lip cancer is crucial to the formation of the management plan for these patients. The most common predisposing factor is chronic actinic damage sustained by a light-complected patient. Xeroderma pigmentosa and basal cell nevus syndrome are genetic examples of predisposing factors. Immunosuppression, especially for organ transplantation has been associated with a higher incidence of squamous cell carcinoma and keratoacanthoma. Chronic irritation, ulceration and contracture in burn patients have been associated with the development squamous cell carcinoma, as has the development of sinus tracts in chronic osteomyelitis. Size, differentiation, and anatomic location are predictors of recurrence. The three modalities available for management of skin cancer are surgical excision, radiotherapy, and Moh's therapy. Comparison of the relative efficiency of thege three treatment methods is difficult because of the lack of randomization or controls in reports of the respective approaches. Intuitive reasoning indicates that surgical excision and reconstruction is more convenient, cost effective, and recurrence free.--R.H. HAUG Reprint request to Dr Luce: Division of Plastic Surgery, Kentucky Clinic, Suite K454, 740 South Limestone, Lexington, KY 405360284.

Reconstruction of t]he Cranial Base Defect. Neligan PC, Boyd JB. Clin Plast Surg 22:71, 1995 Cranial base resection and reconstruction is the newest frontier in head and neck cancer surgery. Advances in surgical, anesthetic, and imaging technology has enabled the treatment of these lesions. The classification of the base of the skull for tumor reconLstruction has improved over the years from simple anatomic locations to a system based on both anatqrnic boundaries and tumor growth patterns. Region I includes the anterior cranial fossa, with extension down to the clivus and foramen magnum. Region II tumors arise laterally, and primarily involve the infratemporal and pterygopalatine fossae with extension into the middle cranial fossa through various forar~fina. Region III lesions arise posteriorly within or around the temporal bone and extend intracranially into the middle or posterior cranial fossae. Reconstruction of region I defects are dictated by the size and position of the defect. Free tissue transfer is best for large defects, whereas regional flaps are effective for small or moderate voids. Several important vascular and neurologic structures including the internal carotid artery, the branches of the trigeminal nerve, the facial nerve and the anriculotemporal nerve pass through region II. Reconstruction is again based on the size and location of the defect. Scalp rotation; temporalis, pectoralis major, trapezius and free abdominous rectus flaps are effective. Region III defects are effectively treated by local, regional, or free flaps. The principles of management of reconstruction in this area include a tight dural seal, obliteration of the dead space, suspension and support of the neural