Surgical Management of Panfacial Fractures.

The evaluation and management of a patient with panfacial fractures are multifaceted. Herein, we describe basic facial skeletal anatomy, considerations for airway securing, and common concurrent injuries. Finally, we discuss primary and secondary reconstructions of facial trauma including sequencing of repair, available landmarks, and the utility of intraoperative computed tomography imaging and virtual surgical planning with custom implants.

The Role of External Fixation in Trauma and Reconstruction of the Mandible in the Age of Rigid Fixation.

Internal rigid fixation is the gold-standard treatment for facial fractures, but there are some specific cases that are more amenable to external fixation (ex-fix) application. Herein, we discuss advantages and disadvantages to ex-fix in the modern treatment of comminuted mandible fractures, infected mandible fractures, fractures of the condylar region, oncologic mandibular resection, pediatric mandible fractures, and fractures in the edentulous patient.

Management of Complications and Secondary Deformity After Fractures of the Midface, Orbit, and Upper Third of the Maxillofacial Skeleton.

Craniomaxillofacial trauma is a challenging entity to manage effectively and often necessitates serial evaluation and treatment. A multidisciplinary team is best served to evaluate and treat these complex injury patterns with the use of necessary adjuncts, such as neuronavigation, intraoperative imaging, custom implant use, and virtual surgical planning. Complications of facial trauma can present at a spectrum of time points and manifest in a variety of manners and as such patients should be observed closely and longitudinally. Although not all complications and secondary deformities can be avoided, this article highlights some common pitfalls and our unique management strategies.

Injectate volumes needed to reach specific landmarks in s1 transforaminal epidural injections.

OBJECTIVES: We identify the contrast volumes needed to reach specific landmarks during S1 transforaminal epidural injections (S1-TFEIs). DESIGN: Prospective, nonrandomized, observational human study. Setting. Academic/private pain management practice. Subjects. Forty-two patients undergoing S1-TFEIs were investigated. Thirty-seven patients were included in this study. Interventions. S1-TFEIs were performed using contrast-enhanced fluoroscopic visualization. MAIN OUTCOME MEASUREMENTS: After confirming appropriate spinal needle position, up to 5 mL of nonionic contrast was slowly injected. Under biplanar fluoroscopic guidance, contrast volumes were recorded as flow reached specific anatomic landmarks: the ipsilateral S1 pedicle, the superior aspect of the L5-S1 disc space, and across the midline of the spinous process. RESULTS: After injecting 2 mL of contrast, 100% of S1-TFEIs spread to the medial aspect of the ipsilateral superior pedicle of S1. After injecting 3.0 mL of contrast, 92% of S1-TFEIs spread to the superior aspect of the L5-S1 intervertebral disc. After injecting 4 mL of contrast, 27% of S1-TFEIs spread beyond the midline of the spinous process, but by only a few millimeters. CONCLUSIONS: This study demonstrates injectate volumes needed to reach specific anatomic landmarks in S1-TFEIs. A volume of 3.0 mL of contrast reaches the superior aspect of the L5-S1 intervertebral disc 92% of the time.

Osteoradionecrosis of the Midface and Mandible: Pathogenesis and Management.

Radiation therapy is an important and commonly used treatment modality for head and neck cancers. Osteoradionecrosis (ORN) is a potential debilitating complication of treatment, which most commonly affects the mandible. Management strategies are tailored to the severity of disease. Medical management including oral rinses, irrigations, antibiotics, and pharmacological treatments is viable for mild-to-moderate ORN. More severe disease is best addressed with a combination of medical management and surgical intervention aimed at aggressively removing devitalized tissue until bleeding bone is encountered and reconstructing the soft tissue and bone defect. Reconstruction with either regional vascularized flaps or vascularized osteocutaneous free flaps in case of larger full-thickness bone defects (greater than 6 cm) or anterior mandible (medial to mental foramen) is most appropriate. Maxillary ORN complications can present with a wide range of functional problems and facial disfigurement. Life-threatening and time-sensitive problems should be treated first, such as skull base bone coverage or correction of severe ectropion, to avoid blindness from exposure keratopathy. Then, less time-sensitive issues can be addressed next, such as nasal obstruction, velopharyngeal insufficiency, and chronic tearing. It may require a combination of specialists from different disciplines to address various issues that can arise from maxillary ORN.

Opioid sparing multimodal analgesia treats pain after head and neck microvascular reconstruction.

OBJECTIVE: To compare pain control (opioid consumption and postsurgical pain scores) in head and neck (H&N) free flap reconstruction patients who undergo traditional means of postoperative analgesia including use of opioids versus a novel protocol that includes ketamine and gabapentin. METHODS: Single-institution retrospective cohort study. RESULTS: Eighty-six patients who underwent H&N free flap reconstruction from 2015 to 2018 were included. Forty-three patients were in the control cohort treated with opioids only, and 43 patients were in the treatment group. There was a statistically significant decrease in opioid consumption in each of the first 5 postoperative days ranging from 80% to 83% in the treatment group. The daily pain scores were significantly lower in the treatment group in the first 2 postoperative days. At the 1-month postoperative visit, there was no significant difference in pain scores between the groups; however, by the 2-month visit, the treatment group reported significantly lower pain scores than the control group (P = 0.001). No adverse outcomes of ketamine or gabapentin were experienced. CONCLUSION: Ketamine and gabapentin are safe and effective analgesics in H&N free flap surgery that significantly decrease opioid use in the acute postoperative setting and may improve pain control. LEVEL OF EVIDENCE: 3a Laryngoscope, 130:1686-1691, 2020.

Botulinum toxin a in the treatment of chronic tension-type headache with cervical myofascial trigger points: a randomized, double-blind, placebo-controlled pilot study.

OBJECTIVE: To evaluate the efficacy of botulinum toxin A (BT-A) as a prophylactic treatment for chronic tension-type headache (CTTH) with myofascial trigger points (MTPs) producing referred head pain. BACKGROUND: Although BT-A has received mixed support for the treatment of TTH, deliberate injection directly into the cervical MTPs very often found in this population has not been formally evaluated. METHODS: Patients with CTTH and specific MTPs producing referred head pain were assigned randomly to receive intramuscular injections of BT-A or isotonic saline (placebo) in a double-blind design. Daily headache diaries, pill counts, trigger point pressure algometry, range of motion assessment, and responses to standardized pain and psychological questionnaires were used as outcome measures; patients returned for follow-up assessment at 2 weeks, 1 month, 2 months, and 3 months post injection. After 3 months, all patients were offered participation in an open-label extension of the study. Effect sizes were calculated to index treatment effects among the intent-to-treat population; individual time series models were computed for average pain intensity. RESULTS: The 23 participants reported experiencing headache on a near-daily basis (average of 27 days/month). Compared with placebo, patients in the BT-A group reported greater reductions in headache frequency during the first part of the study (P = .013), but these effects dissipated by week 12. Reductions in headache intensity over time did not differ significantly between groups (P = .80; maximum d = 0.13), although a larger proportion of BT-A patients showed evidence of statistically significant improvements in headache intensity in the time series analyses (62.5% for BT-A vs 30% for placebo). There were no differences between the groups on any of the secondary outcome measures. CONCLUSIONS: The evidence for BT-A in headache is mixed, and even more so in CTTH. However, the putative technique of injecting BT-A directly into the ubiquitous MTPs in CTTH is partially supported in this pilot study. Definitive trials with larger samples are needed to test this hypothesis further.

Free-Flap Reconstruction of the Tongue.

The tongue is paramount to natural speech and swallowing, and good tongue function is important in the overall quality of life. Autologous free-flap reconstruction of the tongue after glossectomy allows for adequate speech, swallow, and quality-of-life outcomes in a majority of patients. Herein, the authors review autologous free-flap reconstruction of the tongue with a focus on different flap options, speech and swallow outcomes, quality-of-life outcomes, and factors that affect how patients perform after tongue reconstruction.

Impact of Middle Turbinectomy on Airflow to the Olfactory Cleft: A Computational Fluid Dynamics Study.

BACKGROUND: The impact of middle turbinate resection (MTR) on olfaction remains a point of debate in the current literature. Few studies have objectively evaluated olfactory cleft airflow following MTR; thus, the mechanism by which MTR may impact olfaction is poorly understood. It is not known whether the postsurgical changes in airway volume, flow, and resistance increase odorant transport or disrupt the patterns of normal airflow. Computational fluid dynamics can be used to study the nasal airway and predict responses to surgical intervention. OBJECTIVE: To evaluate the functional impact of MTR on nasal airflow, resistance, and olfaction. METHODS: Five maxillofacial computed tomography scans of patients without signs of significant sinusitis or nasal polyposis were used. Control models for each patient were compared to their corresponding model after virtual total MTR. For each model, nasal airway volume, nasal resistance, and air flow rate were determined. Odorant transport of 3 different odorants in the nasal cavity was simulated based on the computed steady airflow field. RESULTS: Total airflow significantly increased following bilateral MTR in all patient models ( P < .05). Consistent with our airflow results, we found a decrease in nasal resistance following MTR. MTR significantly increased area averaged flux to the olfactory cleft when compared to controls for phenylethyl alcohol (high-sorptive odorant). Results for carvone (medium sorptive) were similarly elevated. MTR impact on limonene, a low flux odorant, was equivocal. CONCLUSION: MTR increases nasal airflow while decreasing the nasal resistance. Overall, olfactory flux increased for high sorptive (phenylethyl alcohol) and medium sorpitve (l-carvone) odorants. However, the significant variation observed in one of our models suggests that the effects of MTR on the nasal airflow and the resultant olfaction can vary between individuals based on individual anatomic differences.

Esophageal Perforation due to Anterior Cervical Spine Hardware Placement: Case Series.

Context. This case series discusses surgical management of esophageal perforations that occurred following cervical spine hardware placement. Purpose. (1) Determine presenting symptoms of esophageal perforation after anterior cervical spine hardware placement. (2) Discuss surgical management of these resulting esophageal perforation complications. Design/Setting. Case series of six patients at a tertiary-care, academic medical center. Patient Sample. Six patients with pharyngoesophageal perforations following anterior cervical spine surgery (ACSS). Outcome Measures. Date of ACSS, indication for ACSS, level of hardware, location of esophageal or pharyngeal injury, symptoms at presentation, surgical intervention, type of reconstruction flap, wound culture flora, and antibiotic choice. Methods. A retrospective review of patients with an esophageal or hypopharyngeal injury in the setting of prior ACSS managed by the otolaryngology service at a tertiary, academic center between January 2015 and January 2019. Results. Six patients who experienced pharyngoesophageal perforation following ACSS are included in this study. Range of presentation was two weeks to eight years following initial hardware placement. Five patients presented with an abscess and all had evidence of perforation on initial CT or esophagram. All patients underwent repair with a sternocleidomastoid flap with two patients eventually requiring an additional pectoralis myofascial flap for a persistent esophageal leak. Five patients eventually attained ability to tolerate oral nutrition. An algorithm detailing surgical reconstructive management is proposed. Conclusions. Esophageal perforations in the setting of prior ACSS are challenging clinical problems faced by otolaryngologists. Consideration should be given to early drainage of abscesses and spine surgery evaluation. Spinal hardware removal is recommended whenever possible. Utilization of a pedicled muscle flap reinforces primary closure and allows coverage of the vertebral bony defect. Nutrition, thyroid repletion, and culture-directed IV antibiotics are necessary to optimize esophageal perforation repair.

Higher Complication Rates in Self-Inflicted Gunshot Wounds After Microvascular Free Tissue Transfer.

OBJECTIVES/HYPOTHESIS: Microvascular free tissue transfer is often employed to reconstruct significant facial defects from ballistic injuries. Herein, we present our comparison of complications between self-inflicted and non-self-inflicted gunshot wounds after microvascular free tissue transfer. STUDY DESIGN: Retrospective case review. METHODS: Approval was obtained from the JPS institutional review board. We performed a retrospective review of cases of ballistic facial injuries between October 1997 and September 2017 that underwent vascularized free tissue transfer for reconstruction. Comparisons were made between self-inflicted and non-self-inflicted gunshot wounds after microvascular free tissue transfer. The χ2 test was used for all comparisons. P value and 95% confidence interval (CI) were reported. RESULTS: There were 73 patients requiring free flap reconstruction after gunshot wounds to the face during the study period. There was a statistically significant difference in the rates of nonunion between self-inflicted and non-self-inflicted wounds (P = .02, 95% CI: 0.9 to 35.8) There were also no significant differences in flap failure (P = .10, 95% CI: -2.8 to 24.2), plate exposure (P = .28, 95% CI: -6.7 to 33.0), wound infection (P = .40, 95% CI: -8.9 to 31.2), scar contracture (P = .60, 95% CI: -8.1 to 25.1), and fistula formation (P = .13, 95% CI: -2.8 to 28.8) between patients with self-inflicted and those with non-self-inflicted wounds. Overall, complication rates were significantly higher in the self-inflicted group compared to the non-self-inflicted group (P < .0001, 95% CI: 32.6 to 68.6). CONCLUSIONS: Patients with self-inflicted injuries had more complications postoperatively than those with non-self-inflicted injuries. This is likely helpful in surgical planning and patient counseling. LEVEL OF EVIDENCE: 4 Laryngoscope, 129:837-840, 2019.

Contrast flow selectivity during transforaminal lumbosacral epidural steroid injections.

BACKGROUND: Lumbosacral transforaminal epidural steroid injections (LS-TFESIs) are an accepted procedure used in the comprehensive, conservative care for lumbar disc pathology and/or spinal stenosis induced low back pain with a radicular component. Historically, the terminology used to describe the transforaminal technique of instilling medications into the epidural space and/or exiting structures has varied. These procedures have also been referred to as either diagnostic or therapeutic selective nerve root blocks (SNRBs). Although this procedure is typically used to "selectively" treat isolated pathology, the "SNRB" terminology suggests that one can selectively diagnose or treat a specific nerve root as a pain generator by anesthetizing or blocking it. It has been recently demonstrated that L4 and L5 SNRBs are often non-"selective" by investigating the extent of epidural contrast flow patterns after injecting 1.0 mL of contrast. Our study attempts to identify the minimum injectate volume at which LS-TFESIs may still be considered "selective" with no injectate extending to either the adjacent (superior and/or inferior) levels or to the contralateral side. OBJECTIVE: Quantitatively evaluate contrast flow level selectivity noted during fluoroscopically guided lumbosacral transforaminal epidural steroid injections (LS-TFESIs). STUDY DESIGN: Prospective, nonrandomized, observational human study. METHODS: Thirty patients (female = 10, male = 20) undergoing LS-TFESIs were investigated. After confirming appropriate spinal needle position with biplanar imaging, 4.0 mL of nonionic contrast was slowly injected. Fluoroscopic images were recorded at 0.5 mL increments. These biplanar contrast flow images were evaluated to determine which 0.5 mL volume increment was no longer specific for the injected level. In particular, we documented when contrast extended either to a superior or inferior spinal segment or crossed the midline spine to the contralateral side. RESULTS: After injecting 0.5 mL of contrast, 30% of LS-TFESIs performed in this study were no longer "selective" for the specified root level. After injecting 1.0 mL of contrast, 67% of LS-TFESIs performed in this study were no longer "selective" for the specified root level. After injecting 1.5 mL of contrast, 87% of LS-TFESIs performed in this study were no longer "selective" for the specified root level. After injecting 2.5 mL of contrast, 90% of LS-TFESIs performed in this study were no longer "selective" for the specified root level. CONCLUSIONS: Diagnostic LS-TFESI or SNRB blocks limiting injectate to a single, ipsilateral segmental level cannot reliably be considered diagnostically selective with volumes exceeding 0.5mL. Injectate volumes greater than 0.5mL are consistently non-selective and cannot be used reliably for diagnostic block procedures in the epidural space.

Computational Fluid Dynamics to Evaluate the Effectiveness of Inferior Turbinate Reduction Techniques to Improve Nasal Airflow.

IMPORTANCE: Inferior turbinate reduction (ITR) is a commonly performed procedure for the treatment of nasal obstruction. Which portion of the inferior turbinates should be surgically addressed to improve nasal airflow has yet to be determined. OBJECTIVE: To use computational fluid dynamics (CFD) analysis to evaluate the airflow changes after reduction along different portions of the inferior turbinate. DESIGN, SETTING, AND PARTICIPANTS: Computed tomographic scans of 5 patients were selected. Seven CFD models were created for each patient: 1 unaltered and 6 various ITRs, including 3 one-third ITRs (anterior, middle, and posterior one-third); 2 two-thirds ITRs (anterior and posterior two-thirds); and 1 full-length ITR model. Total airflow rate and nasal resistance was obtained through CFD analysis, and regression analysis was performed on the increased nasal volume, locations, and nasal resistance for all 5 patients. MAIN OUTCOMES AND MEASURES: Total airflow rate and nasal resistance was obtained through CFD analysis, and regression analysis was performed on the increased nasal volume, locations, and nasal resistance for all 5 patients. RESULTS: Full ITR over the whole length was consistently most effective to improve nasal airflow and resistance for all 5 patients (2 men and 3 women), adjusted for the volume. Regression analysis showed a strong linear (R2≥0.79) relationship between nasal volume changes and nasal airflow. However, the most effective location of partial turbinate reduction was not consistent among patients. Surprisingly, for some patients, posterior ITRs were more effective than anterior ITRs. The site of most effective partial ITR differed from 1 side to the other even in the same individual. CONCLUSIONS AND RELEVANCE: The effectiveness of partial ITR and target location likely depends on individual patient anatomy. The fact that full ITRs were consistently most effective and the linear regression between flow and nasal volume changes may indicate that the entire length of the IT has a functional impact on nasal airflow and resistance. LEVEL OF EVIDENCE: NA.

Cerebral embolic stroke and arm ischemia in a teenager with arterial thoracic outlet syndrome: a case report.

A rare presentation of arterial thoracic outlet syndrome (TOS) is described in a young woman. Arterial TOS caused by a cervical rib produced acute upper extremity ischemia due to subclavian artery aneurysm formation. Clinical presentation also included left hemiparesis caused by right subclavian artery thrombosis and retrograde embolization of thrombus via the common carotid artery to the right middle cerebral artery distribution. Surgical repair of the subclavian artery was performed, but permanent neurologic deficit remained. Acute thrombosis of the right subclavian artery can produce cerebrovascular complication. The assessment of such risk in patients with arterial TOS is warranted and the arterial lesion corrected surgically.

Alopecia Following Bicoronal Incisions.

IMPORTANCE: Multiple techniques may be used to perform bicoronal incisions, and alopecia is a known postoperative complication of this procedure. To date, no large studies exist comparing alopecia outcomes among bicoronal incision techniques with and without the use of Raney clips. OBJECTIVE: To determine (1) whether postoperative alopecia is more common when bicoronal incisions are performed with monopolar cautery, Colorado microdissection tip cautery, or traditional cold steel and (2) whether this outcome is affected by the use of Raney clips. DESIGN, SETTING, AND PARTICIPANTS: This retrospective study of postoperative alopecia included 505 patients undergoing bicoronal incisions in a single head and neck surgery practice from 1997 to 2015 with a minimum follow-up of 1 year. Patients with preexisting baldness as well as patients not following up for the minimum period were excluded. All data analysis took place between 1997 and 2015. MAIN OUTCOMES AND MEASURES: Maximum alopecia width was measured in the postoperative period and compared among the technique groups both with and without Raney clip use. Raney clip duration as a product of surgery length was also compared. RESULTS: A total of 505 patients (301 male, 204 female) ranging in age from 3 to 97 years were included in the study (median age, 53.9 years). Of these, 236 underwent bicoronal incisions to approach the skull base, 78 to treat chronic frontal sinusitis unresponsive to endoscopic management or frontal sinus mucocele, 143 for trauma, and 48 for craniofacial surgery. For 173 patients, the cold steel technique was used for both skin and subcutaneous incision, 102 of whom needed Raney clips. For 161 patients, cold steel technique was used for skin incisions and monopolar cautery for subcutaneous incision; 81 of these patients required Raney clips. For 171 patients, Colorado tip microdissection cautery was used for both skin and subcutaneous incision, with Raney clips used in 66 of these patients. Incisions made with cold steel for both skin and subcutaneous tissue, regardless of Raney clip use, had lower postoperative alopecia than those made with cautery: for scalpel use for both skin and subcutaneous tissue, average alopecia width was 2.8 mm without Raney clip and 3.5 mm with Raney clip. For scalpel use with skin and monopolar cautery for subcutaneous tissue, average alopecia width was 3.8 mm without Raney clip and 4.3 mm with Raney clip. Colorado tip microdissection cautery used for skin and subcutaneous tissue was associated with the greatest alopecia width: Colorado tip for skin and subcutaneous tissue, average alopecia width, 4.9 mm; with Raney clip, 5.9 mm. Duration of Raney clip use was significantly associated with increased alopecia width: less than 3 hours, 4.1 mm; 3 hours or more, 5.2 mm (P < .001). CONCLUSIONS AND RELEVANCE: When performing bicoronal incisions, postoperative alopecia can be minimized by preferentially using a cold steel scalpel for skin and subcutaneous incisions. Raney clip use should be avoided when possible or used for only a short time during the procedure. LEVEL OF EVIDENCE: 3.

Fluoroscopic axial imaging in percutaneous lumbosacral procedures: An underutilized technique.

BACKGROUND: The L4-5 and L5-S1 intervertebral disc spaces are the most frequent sites of discal spinal pathology, hence, diagnostic and therapeutic interventions are commonly performed at these levels. While performing fluoroscopically guided spinal procedures such as discography or intradiscal electrothermal anuloplasty (IDEA), antero-posterior (AP), lateral, and oblique views are utilized. However axial projection is not typically possible without three-dimensional imaging such as computerized tomography (CT). Intraprocedural CT is not commonly available. Instead, post-discography CT axial views are used to grade the degree of disruption. However, post-procedural CT is not always immediately available, and it increases costs and may increase patient discomfort, inconvenience, and radiation exposure. Intra-procedure fluoroscopic axial (F-axial) views offer the benefit of dynamic information by helping confirm needle, introducer, or intradiscal catheter position. OBJECTIVE: To describe an alternative approach to axial imaging of the L5-S1 intradiscal space. SETTING: Spine Speciality Center. TECHNIQUE: We describe a simple technique for visualizing L5-S1 axial images intra-procedurally using F-axial views. Taking advantage of the patient's lordosis, the C-arm image intensifier is rotated cadally so F-axial images are obtained. We also demonstrate other uses of intra-procedural F-axials, including confirmation of discography needle placement and IDEA introducer and catheter positioning. CONCLUSION: The L4-5 and L5-S1 intervertebral disc spaces are frequent sites of discal spinal pathology. Multiple diagnostic and therapeutic procedures are performed at these levels. This report describes an adjunctive technique for visualizing the L5-S1 axial images intra-procedurally using a fluoroscopic axial (F-axial) view.

Facial nerve trauma: evaluation and considerations in management.

The management of facial paralysis continues to evolve. Understanding the facial nerve anatomy and the different methods of evaluating the degree of facial nerve injury are crucial for successful management. When the facial nerve is transected, direct coaptation leads to the best outcome, followed by interpositional nerve grafting. In cases where motor end plates are still intact but a primary repair or graft is not feasible, a nerve transfer should be employed. When complete muscle atrophy has occurred, regional muscle transfer or free flap reconstruction is an option. When dynamic reanimation cannot be undertaken, static procedures offer some benefit. Adjunctive tools such as botulinum toxin injection and biofeedback can be helpful. Several new treatment modalities lie on the horizon which hold potential to alter the current treatment algorithm.

Highly specific V3 peptide enzyme immunoassay for serotyping HIV-1 specimens from Thailand.

OBJECTIVE: To develop and evaluate a simple V3 peptide-based enzyme immunoassay (EIA) for large-scale serotyping of HIV-1 specimens from Thailand. DESIGN: Serologic reactivities with synthetic peptides derived from the V3 loop of gp120 were used for typing HIV-1 specimens. METHODS: Synthetic peptides PND-A and PND-B, derived from the consensus amino-acid sequences of the V3 loop of gp120 from two major genomic variants of HIV-1 in Thailand (A and B), were evaluated in an EIA on 61 Thai HIV-1 sera for which genotypes had been determined by polymerase chain reaction. The peptide EIA was then applied to sera from 188 HIV-1-infected patients, selected in non-random, convenience samples of known risk groups from four geographic regions of Thailand. RESULTS: The sensitivities and specificities of PND-A and PND-B were 86% (30 out of 35) and 96% (25 out of 26) and 92% (24 out of 26) and 94% (33 out of 35), respectively, with 100% predictive values of a monoreactive positive test for both peptides. The assay classified 101 specimens as serotype A, 39 as serotype B, eight as serotype AB (dually reactive), and 40 as untypable (non-reactive). Excluding dual reactors and non-reactors, 92% (77 out of 84) of specimens from patients probably infected by sexual contact were serotype A; conversely, 76% (28 out of 37) of injecting drug users were serotype B. CONCLUSION: The serologic results corroborated previous findings, in a smaller subset of samples, of an apparent segregation of viral subtypes by mode of transmission, suggesting two separate HIV-1 epidemics in Thailand. This peptide EIA could be a valuable epidemiologic tool in determining the dynamics of the rapid spread of HIV-1 in Thailand.

PIP: A simple synthetic enzyme immunoassay (EIA) for serotyping HIV-1 specimens from Thailand, based on gp120 V3 loop peptide, was developed and tested on 188 sera from 4 regions of the country. There are 2 major known gene variants of HIV-1 in Thailand designated genotype A and B. The peptide EIA was tested on 61 sera that had been characterized by polymerase chain reaction and DNA sequencing. The EIA was then tested on 188 sera from high risk groups collected in the northern, northeastern, central and southern regions in mid-1991. The PND-A assay was 86% sensitive and 96% specific; the PND-B assay was 96% sensitive and 92% specific. The EIAs showed 100% predictive values when sera known to be reactive to only HIV A or B were tested. In the series there were also 8 sera reactive to both A and B and 40 not reactive to either variant. Excluding dual and non-reactors, 92% of patients with sexual high risk factors had HIV-1 type A and 76% of those with IV drug use history had type B. The results suggest that 2 HIV-1 epidemics have occurred in Thailand, an initial wave in 1988 among IV drug users and a later wave centered among prostitutes and their clients.

Risk factors for HIV-2 infection in Guinea-Bissau.

To define the epidemiology of HIV-2 infection, we conducted a case-control study among hospitalized patients at an acute care hospital in Bissau, Guinea-Bissau, a country with endemic HIV-2 infection. Among 128 patients with various diagnoses, 23 (18%) were positive for HIV-2 by ELISA and Western blot. One of these patients was serologically reactive for HIV-1 also, but PCR and viral culture revealed the presence of HIV-2 only. To study risk factors, behaviors, and AIDS knowledge related to the acquisition of HIV infection, 22 HIV-2-seropositive and 21 seronegative hospitalized patients were given a physical examination and administered a questionnaire. Among women, transfusion was associated with HIV-2 infection (OR = 14.4, p = 0.02); among men, sex with a prostitute was the principal risk factor (OR = undefined, p = 0.02). Although 79% of HIV-infected patients and controls had heard of AIDS, only 17% of all study participants and 50% of males reporting sex with prostitutes had used condoms in the previous year. These data suggest that the risk factors for HIV-2 infection are similar to those for HIV-1 and support previous studies showing that HIV-2 is the predominant HIV in Guinea-Bissau. Efforts to decrease transmission of HIV-2 should include screening for HIV-2 in blood for transfusion in endemic areas (now done in Bissau) and education about the risk of sexual transmission.