Anatomic and high-resolution computed tomographic angiography study of the lateral femoral condyle flap: Implications for surgical dissection

The Vascular Anatomy and Harvesting of the Lateral Femoral Condyle Flap in Pigs

BACKGROUND

 Clinically, there has been increasing employment of the lateral femoral condyle flap. The objective of this study was to explore the vascular anatomy of the lateral femoral condyle in pigs and to explore the feasibility of using pigs as an animal model of the lateral femoral condyle flap.

METHODS

 A total of 20 fresh cadaveric hindlimbs of 4-week-old hybrid pigs were used in this study. The origination, course, and branches of the nourishing vessels of the lateral femoral condyle were observed in 15 specimens. The primary parameters included the variability in the anatomy of the vessels and the length and outer diameter of the vessels. Surgical procedures for the lateral femoral condyle flap were conducted on five specimens.

RESULTS

 The primary nourishing arteries of the lateral femoral condyle in pigs were the first superolateral geniculate artery, which was observed in all 15 specimens and had a diameter and length of 1.99 ± 0.44 mm and 2.27 ± 0.46 cm, respectively, as measured at their origination. The operation was performed in the lateral position. A 10-cm skin incision was made from the lower edge of the patella to the posterior lateral side of the distal femur. After blunt dissection of the intermuscular septum between the biceps femoris and vastus lateralis, the whole course of the first superolateral geniculate artery was exposed.

CONCLUSION

 The vascular anatomy of the lateral femoral condyle in pigs and that of humans exhibited great similarities. The harvesting of the lateral femoral condyle flap in pigs was as easy as that in humans. Pigs could serve as a suitable animal model for the lateral femoral condyle flap.

The Chimeric LFC and DCIA Flap in Combined Mandibular and Condylar Head and Neck Reconstruction-A Case Series

Background: Defects of the ascending ramus of the mandible, including the condylar head and neck or the whole temporomandibular joint (TMJ), are difficult to reconstruct. Reconstruction is mainly based on the use of alloplastic joint prosthesis, costochondral grafting, distraction osteogenesis of the dorsal part of the mandibular ramus, or osseous microvascular flaps of various origin. With the objective of developing a method that overcomes the restrictions of these methods, we recently introduced a sequential chimeric flap consisting of a lateral femoral condyle flap (LFC) and deep circumflex iliac artery flap (DCIA) for reconstruction of up to half of the mandible and the condylar head and neck. Methods: The chimeric flap was used in four patients with the following diagnoses: therapy-refractory osteomyelitis, extended recurrent odontogenic keratozyst, Goldenhar syndrome, and adenocarcinoma of the parotid gland. After a diagnostic workup, LFC and DCIA flaps were harvested in all patients and used in a sequential chimeric design for the reconstruction of the mandibular body and condylar head and neck. Results: Follow-up from at least 24 months up to 70 month after surgery showed a successful reconstruction in all four patients. The LFC provided a cartilaginous joint surface, allowing for a satisfactory masticatory function with a stable occlusion and unrestricted mouth opening and preserved or regained lateral and medial excursions in all patients. The DCIA allowed for a bony reconstruction anatomically resembling a non-atrophied mandibular body. No flap-related complications were observed. Conclusions: The sequential chimeric LFC and DCIA flap is an appropriate method for reconstructing up to half of the mandible and the condylar head and neck. It is suitable in cases where alloplastic joint replacement cannot be used or where other methods have failed. Due to the necessity of harvesting two flaps, the burden of care is increased, and a careful indication is required. The technique is reserved for maxillofacial surgeons who have already gained significant experience in the field of microsurgery.

Lateral Femoral Trochlea Osteochondral Flap Reconstruction of Proximal Pole Scaphoid Nonunions

PURPOSE

The medial femoral trochlea flap has been described as a method of scaphoid proximal pole nonunion reconstruction when the proximal pole is deemed nonsalvageable. The lateral femoral trochlea (LFT) is an alternative donor site providing a comparable vascularized convex osteochondral flap. We describe the technique and outcomes of our first 17 cases of LFT flap reconstruction of the proximal scaphoid pole with a minimum follow-up of 14 months.

METHODS

Seventeen of the first 24 patients who underwent LFT scaphoid reconstruction at 3 institutions were able to be contacted for clinical follow-up and chart reviews. We recorded patient age and sex, duration of nonunion, number of previous surgical procedures, details of surgical technique, achievement of osseous union, complications, additional postoperative procedures, preoperative and postoperative pain, and range of motion. Preoperative and postoperative scapholunate and radiolunate angles were analyzed on x-rays and achievement of osseous union on computerized tomography scans.

RESULTS

The average age of patients included was 35 years (range, 16-55 years). Follow-up data were recorded at an average of 33 months (range, 14-62 months). Ten patients had previous procedures (average, 1; range, 0-2). Median duration from trauma to LFT was 3.4 years (range, 8 months-12 years) among patients who had a recognized date of injury. Osseous healing was achieved in 16 of 17 patients and confirmed by computerized tomograpy scan. Twelve patients reported complete pain relief, while 5 reported partial pain relief. Final postoperative range of motion was 59°extension (range, 30°-85°) and 50° flexion (range, 10°-80°), which was comparable to preoperative values. Preoperative (59°) and postoperative (55°) scapholunate angles were similar to normal wrists.

CONCLUSION

Vascularized LFT flaps provide an alternative donor site for vascularized osteochondral reconstruction of proximal pole scaphoid nonunion. Rate of union, range of motion, and pain relief are similar to reported results with medial femoral trochlea flap reconstruction.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Genicular Artery Embolization: A Review of Essential Anatomic Considerations

Genicular artery embolization is increasingly recognized as a safe and effective treatment option for symptomatic knee osteoarthritis and recurrent hemarthrosis after total knee arthroplasty. Genicular arteries are an essential contributor to vascular supply for the knee joint and demonstrate considerable variability. Familiarity with the anatomy and common variations is critical for preprocedural planning, accurate target selection, and minimizing adverse events in transarterial embolization procedures. This review aimed to provide a detailed discussion of the genicular artery anatomy that is relevant to interventional radiologists performing genicular artery embolization.

Lateral Femoral Trochlea Flap Reconstruction of the Proximal Capitate: An Assessment of Congruity and Description of Technique

PURPOSE

We examined morphologic similarities of the medial lateral femoral trochlea (MFT) and lateral femoral trochlea (LFT) osteochondral flaps for reconstruction of the proximal capitate.

METHODS

Magnetic resonance imaging scans of the wrists and ipsilateral knees of 10 young healthy volunteers were obtained. Three morphologic parameters were investigated, comparing the MFT and LFT harvest sites to the capitate proximal pole. The correspondingly relevant surgical planes were compared. The coronal plane radius of curvature (ROC) of the capitate was compared with the sagittal planes of the MFT and LFT. The sagittal plane ROC of the capitate was compared to the axial planes of the MFT and LFT. The angular relationship between the dorsal cortical surface of the capitate and the proximal pole cartilage (proximal dorsal capitate pitch) was compared to the corresponding angles between the cortical bone and convex cartilage on the LFT and MFT.

RESULTS

The average ratios of ROC for the coronal planes of the capitate to the MFT (0.61) and LFT (0.58) were similar. The average ratios of ROC for the sagittal planes of the capitate to the MFT (0.57) and LFT (0.86) were also similar. The proximal dorsal capitate pitch demonstrated greater similarity to the corresponding shape of the LFT (angular ratio, 1.01) than to that of the MFT (angular ratio, 0.74).

CONCLUSIONS

The LFT and MFT demonstrate similar congruity to the proximal capitate in the sagittal and coronal planes of the wrist. The LFT dorsal pitch closely approximates the relationship of the proximal capitate pole to its dorsal cortical surface.

CLINICAL RELEVANCE

In capitate fracture, fracture nonunion, or avascular necrosis, both the MFT and LFT demonstrate similarity to the proximal convex capitate morphology. The relationship between the cortical and chondral surfaces of the LFT is morphologically very similar to that of the proximal capitate.

Limitations of Computed Tomography Angiography in Preoperative Planning of Peroneus Brevis Rotational Flap

The distally based peroneus brevis (PB) rotational flap has been shown to be a reliable method of coverage of distal third tibial wounds. The flap is perfused via retrograde flow from distal PB perforators located within 8 cm of the lateral malleolus. The ability to assess patency of these vessels preoperatively facilitates surgical planning, and computed tomography angiography (CTA) has been used for perforator assessment of other lower extremity flaps. The purpose of the present study is to establish the potential utility of standard CTA for locating distal PB perforators by examining uninjured lower extremities.

Methods

Twenty-five patients who underwent bilateral lower extremity CTAs using standard lower extremity protocol were retrospectively identified. Axial two-dimensional images were scanned craniocaudally using our institution's standard CT image viewing software, Merge Radsuite (Merge Healthcare, Hartland, Wis.).

Results

The average location of distal-most PB perforators identified on CT angiogram was 13.1 ± 5.1 cm proximal to the distal fibula, or 34.5% ± 13.5% of total fibular length. Standard CTA was only able to locate a pedicle within 8 cm of the lateral malleolus (20.9% of fibular length) in three of 25 patients (12%).

Conclusions

Previous studies have described a reliable pedicle within 8 cm of the distal fibular tip upon which to design a distally based PB rotational flap. The absence of such perforators in the CT angiogram suggests that standard CT angiogram is not a reliable technique for identifying the patency of such perforators when evaluating the utility of a distally based PB flap.

The condylar capping for microvascular temporomandibular joint reconstruction: A preliminary study

BACKGROUND

Defects of the temporomandibular joint (TMJ) are often difficult to be reconstructed in the correct dimensions and function. This preliminary study aims to describe a novel technique of condylar reconstruction with a microvascular flap in case of deforming arthrosis of the TMJ: condylar capping.

PATIENTS AND METHODS

Four patients between 22 and 62 years old-three females and one male-with severe unilateral arthrosis of the TMJ underwent condylar capping. All patients had already had a failed conservative treatment, followed by arthroscopy with lysis and lavage and later open surgery with total or subtotal diskectomy combined with a condylar arthroplasty. Nevertheless, their pain was still at level six or more on a visual analogue scale. Moreover, they could eat only soft food. At this stage, they underwent condylar capping using an osteochondral lateral femoral condyle (LFC) flap. The surgical technique and the postoperative management are described in detail. Crucially the attachment of the lateral pterygoid muscle to the condylar neck was preserved in all cases. The patients were followed up clinically and by CT scan preoperatively, 6, and 12 months postoperatively.

RESULTS

The mean height of the reconstructed neo-condyle was 6.0 mm, the mean width 16.2 mm, and the mean sagittal length 9.8 mm. The follow-up period ranged from 14 to 64 months. The procedures were uneventful for all patients, and the donor site morbidity was negligible. Twelve months later, the patients were all pain-free and able to have a regular diet. The TMJ and the knee had a normal range of movement and power. Postoperative imaging demonstrated bone healing and stable and anatomically correct condyle reconstruction.

CONCLUSIONS

Based on the author's experience, the condylar capping with the LFC appears promising for reconstructing the condylar head in cases of severe osteoarthritis. Preserving the attachment of the lateral pterygoid muscle allows a complete restoration of the physiologic range of movement, including protrusion and laterotrusion of the mandible.

Vascularized Bone Flaps for the Treatment of Kienböck Disease

Of the many treatments for Kienböck disease, only lunate revascularization procedures provide a direct mechanism for reversing the process of osteonecrosis. Owing to the redundant blood supply of the distal radius and carpus, pedicled flaps are versatile solutions for patients with bone loss but intact cartilage. With the advent of free vascularized flaps, the indications for lunate revascularization procedures are expanding. These flaps can be used when the articular cartilage has been compromised and are suitable options to restore native anatomy in patients previously thought to have unreconstructible disease.

Computed tomography angiography-aided individualized anterolateral thigh flap design in the reconstruction of oral and maxillofacial soft tissue defects

PURPOSE

To evaluate a novel method and computed tomography angiography (CTA) for locating anterolateral thigh flap (ALTF) perforators to design individualized ALTFs to reconstruct maxillofacial soft tissue defects.

STUDY DESIGN

This study comprised a group of 36 patients (CTA group) with malignant oral and maxillofacial tumors who underwent CTA and who received individualized ALTFs and a group of 28 patients (control group) with the same condition but without preoperative CTA examination and with nonindividualized ALTFs. ALTFs in the CTA group were designed and harvested using the locating device and CTA, whereas ALTFs in the control group were designed and harvested according to each surgeon's experience.

RESULTS

Fifty perforators were located and 36 ALTFs harvested in the CTA group. In the control group, 34 perforators were located and 28 ALTFs harvested. Less time was required to locate the perforators in the CTA group. Moreover, the CTA group had a higher flap survival rate and better patient satisfaction regarding the postoperative aesthetics and phonetic and swallowing functions.

CONCLUSIONS

The results suggest that CTA and the locating device can be used to accurately locate ALTF perforators and that this method aids in the design and harvesting of individualized ALTFs to achieve good functional and aesthetic outcomes.

Multimodal Microvascular Mapping for Head and Neck, Skull Base Research and Education: An Anatomical Donor Study

Objective This study was aimed to develop a method combining computed tomography (CT) and fluorescence imaging, allowing identification of microvasculature in anatomical donors and facilitating translational research and education.

Methods We investigated homogeneity and radiopacity of 30 different mixtures including radiopaque substances povidone–iodine (Betadine), barium sulfate (BaSO4), and bismuth subsalicylate (Pepto-Bismol) varying in suspension and dilution with agar, latex, or gelatin. Three candidate mixtures were selected for testing the extent of perfusion in renal vasculature to establish methodology. From these candidate mixtures, two were selected for mixture with fluorescein and infusion into cadavers based on their ability to perfuse renal vasculature. The extent to which these two candidate mixtures combined with fluorescein were able to perfuse vasculature in a cadaver head was used to determine which mixture was superior.

Results BaSO4 and bismuth subsalicylate–based mixtures demonstrated superior opacity in vials. In terms of solidifying agents, gelatin-based mixtures demonstrated increased friability and lower melting points compared with the other agents, so only latex and agar-based mixtures were used moving forward past the vial stage. Combinations of BaSO4 and latex and BaSO4 and 3% agar were found to perfuse kidneys superiorly to the mixture containing bismuth subsalicylate. Finally, in cadaver heads, the mixture containing BaSO4, agar, and fluorescein was found to perfuse the smallest vasculature.

Conclusion A final combination of BaSO4, 3% agar, and fluorescein proves to be a powerful and novel combination enabling CT imaging, fluorescence imaging, and dissection of vasculature. This paves the way for future translational research and education.

[Clinical application of superior lateral genicular artery perforator propeller flap in repair of soft-tissue defects around knee joint]

Objective

To explore the feasibility and effectiveness of using the superior lateral genicular artery (SLGA) perforator propeller flap to reconstruct soft-tissue defects around the knee joint.

Methods

Between October 2013 and May 2019, 10 patients underwent repairing of soft-tissue defects around the knee joint using the SLGA perforator propeller flap. There were 6 males and 4 males, with a median age of 34.5 years (range, 6-66 years). Etiologies included radical tumor resection in 4 cases, post-burn scar contracture in 3 cases, post-burn hypertrophic scar in 2 cases, and prothesis exposure after knee arthroplasty in 1 case. Defects located on the lateral knee in 6 cases, proximal lateral leg in 2 cases, popliteal fossa in 1 cases, and infrapatellar region in 1 case. The size of soft-tissue defects was from 6 cm×4 cm to 14 cm×8 cm. The extraction range of the flap was from 10.0 cm×5.5 cm to 23.0 cm×7.0 cm; the length of the perforator pedicle was 2.5-5.0 cm, with an average of 3.65 cm; the flaps were rotated 180°, the large paddle of the propeller flap was used to repair the defect, and the small paddle was used to assist the closure of donor site.

Results

Blister was observed in the distal 3-cm of one flap and the flap survived after conservative management. All the flaps survived, and the wounds in the donor and recipient areas healed by first intention. There was no vascular crisis, incision dehiscence, infection, or other complications. All 10 patients were followed up 4 to 48 months, with an average of 12.6 months. The color and texture of the flap were similar to those of the recipient area, and there was no need for secondary operation for degreasing and thinning. Scar contracture was corrected; no tumor recurrence was found in tumor patients; the artificial knee joint was preserved, the knee joint flexion and extension activities were good, and all the patient and family members were satisfied with the appearance and function of the lower limbs after operation.

Conclusion

The SLGA perforator propeller flap surgery is relatively simple without the need of microvascular anastomosis, has the minimal donor-site morbidities, and can provide a compound flap for the repairing of a complex wound. The SLGA perforator propeller flap is one of the optional methods to repair soft-tissue defects around the knee joint.

The free vascularized lateral femoral trochlea osteochondral graft: a reliable alternative for Stage III Kienböck's disease

Lunate reconstruction using a lateral femoral trochlea osteochondral graft was carried out in 27 patients with Stage III Kienböck's disease from 2012 to 2019. Twenty-three of these patients could be followed-up in this retrospective study. Ten were women and 13 men. Nine were Lichtman Stage IIIA, seven Stage IIIB and seven Stage IIIC. The mean follow-up was 39 months (range 12-86). Bony consolidation was found in 18 of the 23 patients, with no graft loss. The mean Disabilities of the Arm, Shoulder and Hand score (DASH score) was 11 and the Modified Mayo Wrist Score was 83. There were only two radiological deteriorations, with the same or improved Lichtman classifications in the other patients and a significant reduction in pain. Postoperative extension of the wrist (52°) and flexion (48°) were comparable with preoperative values and, respectively, 81% and 72% of the contralateral side. Grip strength and pinch grip were 32 kg and 12 kg, 88% and 94% of the other hand, respectively, and an insignificant increase compared with the preoperative values. The vascularized lateral femoral trochlea osteochondral graft yields good short- and mid-term results in Grade III Kienböck's disease.Level of evidence: IV.

Evaluation of nerve capture using classical landmarks for genicular nerve radiofrequency ablation: 3D cadaveric study

Background and objectives

Radiofrequency (RF) denervation of the superolateral genicular nerve (SLGN), superomedial genicular nerve (SMGN) and inferomedial genicular nerve (IMGN) is commonly used to manage chronic knee joint pain. However, knowledge of articular branches captured, using classical landmarking techniques, remains unclear. In order to enhance and propose new RF procedures that conceivably capture a greater number of articular branches, more detailed cadaveric investigation is required. The objectives were to (1) determine which articular branches are captured or spared using classical landmarking techniques, and (2) evaluate the anatomical feasibility of classical landmarking techniques using three-dimensional (3D) modeling technology.

Methods

Ultrasound-guided classical superolateral/superomedial/inferomedial landmarking techniques were used to position RF cannulae in five specimens. The articular branches, bony and soft tissue landmarks, and cannula tip position, were meticulously dissected, digitized and modeled in 3D. Simulated lesions were positioned at the cannula tip, on the 3D models, to determine which articular branches were captured or spared. Capture rates of articular branches were compared.

Results

In all specimens, classical superolateral/superomedial techniques captured the transverse deep branches of SLGN and SMGN, and articular branches of lateral and medial nerve to vastus intermedius, while sparing distal branches of SLGN/SMGN. The inferomedial technique captured anterior branches of IMGN while sparing the posterior and inferior branches.

Conclusions

This study provides anatomical evidence supporting the effectiveness of classical landmarking for genicular nerve ablation; however, each technique resulted in sparing of articular branches. The extensive innervation of the knee joint suggests the use of supplementary landmarks to improve capture rates and potentially patient outcomes.

The Superficial Face Dissection as an Example for Integrating Clinical Approaches, Authentic Learning, and Changing Perspectives in Anatomy Dissection

Hands-on dissection-based learning of anatomy offers an unique and valued experience for medical students. Too often however, the inexperienced student's focus is to avoid damage to unfamiliar structures instead of understanding spatial relationships between structures. This results in unfortunate surrender of a critical learning experience. Additionally, approaches to dissection and anatomic exposure share little alignment to clinical approaches, making it less powerful in clinical applicability. The goal of this viewpoint commentary is based on the experience of the two authors and aims to demonstrate opportunity to introduce clinical approaches for dissection while incorporating relevant anatomical concepts in medical school curriculum that aligns with authentic healthcare practice. Using the dissections of the superficial face as a relevant and current topic of clinical interest, we point out that applying the currently performed dissection approach (medial-to-lateral) falls short of providing sufficient knowledge and understanding of the layered arrangement of facial structures. The lateral-to-medial approach, as performed in surgical face lifting procedures would offer a better understanding of the layers of the face and especially the superficial musculoaponeurotic system (SMAS) accounting for the difficulties of facial dissections on embalmed cadavers. This commentary could offer a potential change in paradigm for students and course facilitators for how to maximize the knowledge transfer during facial dissections. It potentially opens a door to rethink dissection-based learning of anatomy toward techniques and approaches that are aligned to surgical access pathways and thus considered more clinically relevant.

Vascular coverage of the anterior knee region - an anatomical study

Descriptions of vessel angiosomes or perforasomes throughout the human body are quite frequent, and led to the development of flaps nowadays commonly used to surgically cover skin and soft tissue defects. In these procedures, the surgeon requires a profound anatomical knowledge of the respective blood vessels and the extent of the perfused area to define the size of the graft. In the region of the knee joint, descriptions of flaps based on the superior lateral genicular artery and descending genicular artery are quite frequent. In contrast, information regarding other popliteal branches is scarce or non‐existent. The aim of this study was to provide a concise and complete overview on the extent and variability of the perforator angiosomes of the femoral and popliteal arteries in the anterior knee region. Twenty lower extremities were dissected, the respective perforators identified and perfused with dye. All resulting angiosomes were marked and documented. A total of 84 angiosomes were identified in all specimens, with an average of 4.2 (3–6) angiosomes per specimen. The average size of the angiosomes was 97.04 ± 72.30 cm² (8.61–360.41 cm²), their source vessels had an average diameter of 1.42 ± 0.54 mm (0.60–3.25 mm). The complex and highly variable distribution of perforator angiosomes of the anterior knee region and especially of its less frequently investigated distal part was demonstrated. Based on these results, the planning of existing perforator flaps in this region and the development of flaps including the inferior medial or inferior lateral genicular arteries may be facilitated.