Evaluation of poly-L-lactic acid and polyglycolic acid resorbable stents for repair of tracheomalacia in a porcine model.

Poly-L-lactic acid and polyglycolic acid (PLPG) resorbable stents may offer a potential solution to the problem of tracheomalacia. Advantages of this material include its strength, its versatile shaping characteristics, and its resorbability, which would preclude surgical removal and allow for airway growth. The purpose of this pilot study was to examine the usefulness of PLPG stents for temporary external airway stenting of tracheomalacia in a porcine model. A severe tracheomalacia was created in 6 pigs by submucosal resection of segments of tracheal cartilage from 6 consecutive rings. The PLPG stent was then shaped to recreate the tracheal contour and sutured to the underlying airway. Endoscopic photodocumentation during spontaneous ventilation was obtained before and after reconstruction. After creation of the malacic tracheal segment, all animals developed stridor, retractions, and cyanosis during spontaneous ventilation. After repair, all animals were extubated without complication. All animals survived the follow-up period of 9 to 12 weeks without evidence of respiratory distress and with rapid weight gain. Repeat bronchoscopy showed no evidence of airway collapse during spontaneous ventilation. Tracheal measurements revealed growth of the stented segment with a mild narrowing within the repaired region. Histologic examination showed preservation of respiratory epithelium. These preliminary findings suggest that PLPG stents may serve a useful role in the surgical management of tracheomalacia.

Use of titanium mesh for reconstruction of large anterior cranial base defects.

The authors evaluated the role of titanium mesh used in combination with vascularized pericranium to provide rigid support during reconstruction of anterior skull base defects. Thirteen patients with large anterior skull base defects caused by tumor invasion or traumatic injury involving the cribriform plate, orbital roof, and planum sphenoidale were included in the study. The reconstruction technique involved placement of titanium mesh between two layers of continuous vascularized pericranium. Surgical glue and routine lumbar cerebrospinal fluid (CSF) drainage were not used in any patient. At a mean postoperative follow-up time of 22 months (range 8-39 months), none of the patients had developed infection or meningocele. Postoperative CSF rhinorrhea occurred in two patients with extensive dural defects, which resolved with temporary lumbar drainage. Use of titanium mesh and a two-layer vascularized pericranial graft is a safe, reproducible, and feasible method for reconstructing the anterior skull base. Patients with large dural defects may need temporary CSF diversion to avoid postoperative fistula formation.

Planned postradiotherapy neck dissection in patients with advanced head and neck cancer.

BACKGROUND: Metastatic neck nodes in patients with squamous cell carcinoma of the head and neck are most commonly managed by surgery, radiotherapy, or combined-modality therapy. For combined-modality cases, the sequencing of surgery and radiotherapy is generally guided by which modality is considered preferable for treatment of the primary tumor. A postradiotherapy neck dissection is often considered for those patients with > N1 disease in which the primary is treated with radiotherapy alone. METHODS: Between February 1991 and October 1995, 25 patients with node-positive squamous cell carcinoma of the head and neck were treated with planned unilateral (n = 22) or bilateral (n = 3) neck dissection following high-dose radiotherapy. The primary tumor sites included: tongue base (n = 11), tonsil (n = 6), nasopharynx (n = 3), pyriform sinus (n = 2), supraglottic larynx, (n = 1), soft palate (n = 1), and unknown head and neck primary (n = 1). The specific nodal stage breakdown of the 28 individual neck dissections (25 patients) was N1 (n = 1), N2A (n = 5), N2B (n = 15), N3 (n = 7). RESULTS: Nineteen of the 28 neck dissections (68%) demonstrated no evidence of residual carcinoma. Of the nine positive neck dissections, six revealed malignant cells in a single nodal echelon. The 1- and 2-year rate of neck control in all 25 patients was 100% and 93%, respectively. The 1- and 2-year disease-specific survival for all 25 patients was 83% and 60%, respectively. With a minimum follow-up of 2 years, 64% of the 25 patients remain alive with no evidence of disease or dead of non-cancer causes. CONCLUSION: In this series of postradiotherapy neck dissections, two thirds of the dissections demonstrated no evidence of residual tumor (19/28, or 68%). However, there was not a direct correlation between pretreatment nodal size (neck staging), radiation dose delivered, and the likelihood of achieving a cancer-free neck dissection. Only one of 28 postradiotherapy neck dissections identified tumor outside of nodal stations II-IV. The predictable pattern of residual disease in pathologically positive cases suggests that a selective neck dissection encompassing levels II-IV may be appropriate in a majority of patients.

Chondrogenesis by free and vascularized rabbit auricular perichondrium.

Many qualitative studies examining the chondrogenic potential of perichondrium have suggested that it may be useful for airway reconstruction. This study was performed to quantitatively evaluate cartilage formation by free and vascularized rabbit perichondrium placed in sterile and contaminated (airway) environments for 8 weeks. The mean cartilage thickness for free sterile perichondrium was 0.09 mm, for free contaminated perichondrium was 0.13 mm, for vascularized sterile perichondrium was 0.16 mm, and for vascularized contaminated perichondrium was 0.44 mm. Contaminated vascularized grafts produced significantly more cartilage when compared to both sterile vascularized grafts (p = .001) and contaminated free grafts (p < .001). No differences in cartilage formation were seen between sterile and contaminated free grafts (p = .198), or between free and vascularized grafts that were sterile (p = .170). These findings support further investigation of airway reconstruction with vascularized perichondrial grafts.

Comparison of the chondrogenic potential of free and vascularized perichondrium in the airway.

Revascularized perichondrium or periosteum may be the ideal graft to repair severe laryngotracheal stenosis because of its pliability, potential for bone or cartilage formation, resistance to infection, and rapid mucosalization. To begin our evaluation of these grafts in airway reconstruction, this study was designed to quantify the chondrogenic capacity of free and vascularized perichondrium placed in the airway. In a rabbit model, free auricular perichondrium (N = 16) produced a mean cartilage thickness of 0.15 mm, whereas vascularized auricular perichondrium (N = 18) produced a mean of 0.45 mm at 8 weeks (p < .0001). In a third group of rabbits (N = 4) vascularized auricular perichondrial grafts were subjected to a 2-hour intraoperative ischemic insult in order to simulate the ischemia of revascularization. The mean cartilage thickness at 8 weeks was 0.50 mm. We conclude that in the rabbit model, vascularized perichondrium provides significantly more cartilage than free perichondrial grafts.

Giant suprastomal granuloma as a laryngeal mass.

The presence of suprastomal granulomas after tracheotomy is a common occurrence. Under most circumstances, this never becomes clinically relevant. However, in the pediatric population, granulomas can on occasion cause partial or complete airway obstruction after decannulation. This report describes 2 cases of giant suprastomal granulomas that presented as laryngeal masses. These cases stress the indications for routine endoscopic evaluation in patients with long-term tracheotomies. Also, the treatment of extensive suprastomal granulomas requires open excision, which differs from the endoscopic approach recommended for smaller granulomas.