Samuel Buonocore

Bridging tendon defects using autologous tenocyte engineered tendon in a hen model.

Tendon defects remain a major concern in plastic surgery because of the limited availability of tendon autografts. Whereas immune rejection prohibits the use of tendon allografts, most prosthetic replacements also fail to achieve a satisfactory long-term result of tendon repair. The tissue engineering technique, however, can generate different tissues using autologous cells and thus may provide an optimal approach to address this concern. The purpose of this study was to test the feasibility of engineering tendon tissues with autologous tenocytes to bridge a tendon defect in either a tendon sheath open model or a partial open model in the hen. In a total of 40 Leghorn hens, flexor tendons were harvested from the left feet and were digested with 0.25% type II collagenase. The isolated tenocytes were expanded in vitro and mixed with unwoven polyglycolic acid fibers to form a cell-scaffold construct in the shape of a tendon. The constructs were wrapped with intestinal submucosa and then cultured in Dulbeccos Modified Eagle Medium plus 10% fetal bovine serum for 1 week before in vivo transplantation. On the feet, a defect of 3 to 4 cm was created at the second flexor digitorum profundus tendon by resecting a tendon fragment. The defects were bridged either with a cell-scaffold construct in the experimental group ( n= 20) or with scaffold material alone in the control group ( n= 20). Specimens were harvested at 8, 12, and 14 weeks postrepair for gross and histologic examination and for biomechanical analysis. In the experimental group, a cordlike tissue bridging the tendon defect was formed at 8 weeks postrepair. At 14 weeks, the engineered tendons resembled the natural tendons grossly in both color and texture. Histologic examination at 8 weeks showed that the neo-tendon contained abundant tenocytes and collagen; most collagen bundles were randomly arranged. The undegraded polyglycolic acid fibers surrounded by inflammatory cells were also observed. At 12 weeks, tenocytes and collagen fibers became longitudinally aligned, with good interface healing to normal tendon. At 14 weeks, the engineered tendons displayed a typical tendon structure hardly distinguishable from that of normal tendons. Biomechanical analysis demonstrated increased breaking strength of the engineered tendons with time, which reached 83 percent of normal tendon strength at 14 weeks. In the control group, polyglycolic acid constructs were mostly degraded at 8 weeks and disappeared at 14 weeks. However, the breaking strength of the scaffold materials accounted for only 9 percent of normal tendon strength. The results of this study indicated that tendon tissue could be engineered in vivo to bridge a tendon defect. The engineered tendons resembled natural tendons not only in gross appearance and histologic structure but also in biomechanical properties.

A proposal for the timing of management of patients with melanoma presenting during pregnancy

The treatment of melanoma during and immediately after pregnancy poses a significant challenge to surgeons, oncologists, and patients alike. With the overall increase in incidence of melanoma in the United States and worldwide, it is likely that more surgeons will be faced with management decisions regarding pregnant patients with melanoma. We report on five patients who presented to the Yale Melanoma Unit with melanoma during their pregnancy. We propose the management option of resection of the primary tumor under local anesthesia, and postponing of the sentinel lymph node biopsy until after the birth of the child. The completion lymphadenectomy can be performed if these nodes are found to be harboring metastases. We further discuss treatment options and propose an algorithm for management of patients diagnosed with melanoma while pregnant. J. Surg. Oncol. 2012; 106:36–40.

Nasal aesthetics: a cross-cultural analysis.

Background: Plastic surgeons often approach nasal aesthetic evaluation with the aid of seemingly objective measurements. However, ideal measurements of an attractive nose, as suggested in the literature, might not apply on a cross-cultural basis. Given these controversies, this study aimed to investigate the cultural and ethnic impact on nasal shape preferences. Methods: Computerized images of a models nose were generated in which the nasal width, root, tip, dorsum, and projection of the lips and chin could be altered. A survey containing these images was sent to over 13,000 plastic surgeons and lay people in 50 different countries, with a total response rate of 9.6 percent. Demographic information about the interviewees was obtained. Results: Preferred dimensions of the nose were broken down according to geographic, ethnic, occupational, and sex variables. Interregional comparison revealed that plastic surgeons from Latin America and the Caribbean overall prefer smaller and narrower noses, with more projecting tips, lips, and chins. Similar trends hold true when analyzing results from the general public. Significant differences were found comparing preferences between plastic surgeons and the general public. Plastic surgeons preferred wider nasal roots and tips and, in combination, more projected nasal dorsi, tips, lips, and chins. Conclusions: No universal parameter can define ideal aesthetics of the nose across cultures and ethnic backgrounds. As demonstrated, geographic, ethnic, and cultural factors influence aesthetic perceptions of patients and surgeons.

The effects of A1 pulley release after flexor tendon repair in a cadaveric model.

Background: Decreasing rupture rates after flexor tendon repair is accomplished by increasing the strength of the repair and by decreasing the forces across tendons during rehabilitation. The authors sought to determine whether A1 pulley release affects work of flexion after a zone 2 flexor tendon repair. Methods: Four fresh-frozen cadaveric hands were thawed to room temperature. The flexor digitorum profundus and flexor pollicis longus tendons were tested in a tensile testing machine. In hands 1 and 2, work of flexion of uninjured tendons was evaluated through the sequential division of the A1 pulley, starting with either the proximal 50 percent or the distal 50 percent of the pulley. In hands 3 and 4, zone 2 flexor digitorum profundus lacerations were created and repaired using a modified Kessler technique; then, sequential division of the A1 pulley was performed. Force-excursion curves were generated and used to calculate work of flexion. Analysis of variance was performed for multigroup comparisons, and t tests were performed for pairwise comparisons. Values of p < 0.05 were considered statistically significant. Results: In uninjured tendons, work of flexion decreased with sequential division of the A1 pulley. After tendon repair, work of flexion increased significantly from baseline in all digits. A1 pulley release after flexor tendon repair produced significant decreases in work of flexion in all digits. Conclusions: A1 pulley release effectively decreases work of flexion after flexor tendon repair. Release performed at the time of tendon repair may decrease the forces across tendons in the postoperative period.

The Effects of Edema and Self-adherent Wrap on the Work of Flexion in a Cadaveric Hand

PURPOSE Early motion protocols after flexor tendon repair often require hand therapy in edematous digits. Self-adherent wraps are used in the postoperative period to reduce edema. The purpose of this study was to determine whether the presence of a self-adherent wrap affected the work of flexion during early motion protocols. METHODS In an unpreserved cadaveric hand, the flexor digitorum profundus and flexor pollicis longus tendons were identified and attached to a tensile testing machine to measure work of flexion (WoF). We simulated subcutaneous edema by injecting normal saline into the digits. Moderate and severe edema was simulated by 10% and 20% increases in circumference of the digits, respectively. We evaluated 2 commonly used products: 2.5-cm Coban self-adherent wrap (3M, St. Paul, MN) and 2.5-cm Co-Wrap cohesive bandage (Hartmann, Rock Hill, SC). Statistical analyses include analysis of variance, 95% confidence intervals for average responses, and graphical display of both data and model predictions. RESULTS In digits without edema or wraps, WoF ranged from 0.0114 J (small finger) to 0.0710 J (thumb). Without wraps, simulated moderate and severe edema was predicted to increase WoF by an average of 23% and 71%, respectively. Application of self-adherent wrap increased WoF values significantly in all digits. In the majority of conditions tested, application of self-adherent wrap increased WoF more significantly than moderate edema did. The effects of edema and self-adherent wrap were additive, producing WoF values 4 times the baseline values. CONCLUSIONS Edema and self-adherent wrap increased WoF in this model. Therapists and surgeons should be aware of increased stress placed on tendons when early motion protocols are initiated in the presence of edema and self-adherent wrap. CLINICAL RELEVANCE We recommend removal of self-adherent wrap before starting a therapy session.

Cadaveric allograft for wound closure after resection of squamous cell carcinoma in patients with recessive dystrophic epidermolysis bullosa: a report of 32 resections and repairs in 2 patients.

This is a review of the management of squamous cell carcinoma in 2 adult patients with recessive dystrophic epidermolysis bullosa. The 2 have undergone 32 excisions of squamous cell carcinoma of the skin and soft tissue with subsequent reconstruction. Multiple strategies for wound closure have been described in this population. We highlight the usefulness of full thickness cadaveric allograft alone, to close wounds in situations when primary closure or donor site availability of autograft is limited or suboptimal.

The Hand Surgeon Consultation Improves Patient Knowledge in a Hand Surgery Mission to Honduras

BACKGROUND The purpose of this study was to assess impact of the surgeon consultation and informed consent process on patient education in an international hand surgery mission compared with a US academic hand surgery practice. These two groups were selected to evaluate communication difficulties in a surgical mission setting compared with standard of care in a high-income country. METHODS A multi-part survey was administered to patients presenting to a hand surgery mission during March 2012 and new patients of a university hand center in a 3-month period during 2011. Surveys were administered prior to and following surgeon consultation with one fellowship-trained hand surgeon. The survey assessed knowledge of basic hand anatomy, physiology, disease, individual diagnosis, and surgical risks. RESULTS 71 patients participated in the study (university n=36, mission n=35). Pre-consultation quiz score averaged 58% in the university group versus 27% in the mission group. Post-consultation quiz scores averaged 62% in the university group versus 40% in the mission group. Only the mission groups quiz score increase was statistically significant. 93% of the university group reported learning about their condition and diagnosis, but only 40% demonstrated correct insight into their diagnosis. In the mission group, 73% reported learning about their condition and diagnosis while 53% demonstrated correct insight into their diagnosis. Although all consultations involved discussion of surgical risks, only 62% of the university group and 52% of the mission group recalled discussing surgical risks. CONCLUSIONS The hand surgeon consultation was more effective in improving hand knowledge in the surgery mission group compared to in a university hand practice. This suggests that the surgeon consultation should be pursued despite communication barriers in surgical missions. However, the discrepancy between patient perception of knowledge gains and correct insight into diagnosis, and the deficit of patient retention of surgical risks need to be improved.

Tunnelled tensor fascia lata flap for complex abdominal wall reconstruction.

This study describes the treatment of two patients with recurrent, infected abdominal wall defects using bilateral delayed and tunnelled pedicled tensor fascia lata (TFL) myofascial flaps. TFL flaps were elevated and delayed for 4 weeks in both cases. In the second case, Parietex Composite mesh was positioned underneath the TFL flap and allowed to incorporate. After a delay of 4 weeks, the flaps were harvested and tunnelled subcutaneously to repair the abdominal wall defect. Both patients have stable repairs but had donor site seromas requiring drainage. Cadaver dissection was also performed to identify structures related to TFL flap harvest. We identified a variant of lateral femoral cutaneous nerve that traversed the TFL flap, necessitating meticulous dissection during surgery. In summary, we describe a new technique of incorporating mesh into the TFL prior to flap harvest for reconstruction of complex abdominal wall.