Uncommon Anatomical Variation of the Facial Artery: A Cadaveric Case Report

The facial artery is a branch of the external carotid artery, one of the major arteries supplying blood to the head and neck. The normal route of the facial artery follows a well-defined path. It typically arises from the external carotid artery, above the superior border of the hyoid bone. During its route, the facial artery gives off branches in the neck, mandible, buccal region, and face. This case report explores a rare anatomical variation of the facial artery characterized by an unusual termination point above the upper lip as the superior labial artery, found during a routine cadaveric dissection. While variations in the course of the facial artery are documented, this particular deviation, with its termination anterior to the typical endpoint, presents a unique anatomical variation.

Adding sacral anchors through an S1 alar screw and multirod construct as a strategy for lumbosacral junction augmentation: an in vitro comparison to S1 pedicle screws alone with sacroiliac fixation

OBJECTIVE

Achieving solid fusion of the lumbosacral junction continues to be a challenge in long-segment instrumentation to the sacrum. The purpose of this study was to test the condition of adding sacral anchors through an S1 alar screw (S1AS) and multirod construct relative to using S1 pedicle screws (S1PSs) alone with sacroiliac fixation in lumbosacral junction augmentation.

METHODS

Seven fresh-frozen human lumbar-pelvic spine cadaveric specimens were tested under nondestructive moments (7.5 Nm). The ranges of motion (ROMs) in extension, flexion, left and right lateral bending (LB), and axial rotation (AR) of instrumented segments (L3-S1); the lumbosacral region (L5-S1); and the adjacent segment (L2-3) were measured, and the axial construct stiffness (ACS) was recorded. The testing conditions were 1) intact; 2) bilateral pedicle screw (BPS) fixation at L3-S1 (S1PS alone); 3) BPS and unilateral S2 alar iliac screw (U-S2AIS) fixation; 4) BPS and unilateral S1AS (U-S1AS) fixation; 5) BPS and bilateral S2AIS (B-S2AIS) fixation; and 6) BPS and bilateral S1AS (B-S1AS) fixation. Accessory rods were used in testing conditions 3-6.

RESULTS

In all directions, the ROMs of L5-S1 and L3-S1 were significantly reduced in B-S1AS and B-S2AIS conditions, compared with intact and S1PS alone. There was no significant difference in reduction of the ROMs of L5-S1 between B-S1ASs and B-S2AISs. Greater decreased ROMs of L3-S1 in extension and AR were detected with B-S2AISs than with B-S1ASs. Both B-S1ASs and B-S2AISs significantly increased the ACS compared with S1PSs alone. The ACS of B-S2AISs was significantly greater than that of B-S1ASs, but with greater increased ROMs of L2-3 in extension.

CONCLUSIONS

Adding sacral anchors through S1ASs and a multirod construct was as effective as sacropelvic fixation in lumbosacral junction augmentation. The ACS was less than the sacropelvic fixation but with lower ROMs of the adjacent segment. The biomechanical effects of using S1ASs in the control of long-instrumented segments were moderate (better than S1PSs alone but worse than sacropelvic fixation). This strategy is appropriate for patients requiring advanced lumbosacral fixation, and the risk of sacroiliac joint violation can be avoided.

Quantifying the Relationship Between the Medial Quadriceps Tendon-Femoral Ligament and Patellar Borders: A Pediatric Cadaveric Study

BACKGROUND

The medial patellofemoral complex (MPFC) is a structure composed of the medial quadriceps tendon-femoral ligament (MQTFL) superiorly and the medial patellofemoral ligament (MPFL) inferiorly. The pediatric MPFL anatomy has been well described, but the precise anatomy of the MQTFL has only recently been described and studied in skeletally immature patients.

PURPOSE

To describe the anatomic relationship between the MQTFL and its insertion on the quadriceps tendon and patella in pediatric specimens.

STUDY DESIGN

Descriptive laboratory study.

METHODS

A total of 22 pediatric cadaveric knee specimens were dissected to analyze attachment of the MQTFL to the quadriceps tendon and patella. Dissection was facilitated using lateral parapatellar arthrotomy followed by eversion of the extensor mechanism to evaluate MQTFL fibers from its undersurface.

RESULTS

The mean specimen age was 7.4 years. Specimens were divided based on age into a younger cohort (1-2 years), middle cohort (4-8 years), and older cohort (9-12 years). The quadriceps tendon attachment (QTA) of the MQTFL proximal to the patella extended a median of 5.0 mm in the younger cohort, 11.4 mm in the middle cohort, and 12.0 mm in the older cohort, with significant differences found between the younger and middle cohorts (P < .047) and the younger and older cohorts (P < .001). The QTA as a percentage of patellar articular height averaged 44.4% across all specimens. The vertical height of the patella measured a median of 14.0 mm, 22.3 mm, and 27.3 mm in the younger, middle, and older cohorts, respectively.

CONCLUSION

This study expands on the recently described anatomy of the pediatric MPFC to quantify the anatomic relationship between the MQTFL attachment to the quadriceps tendon and patella in a more clinically relevant cohort of donor specimens.

CLINICAL RELEVANCE

As access to pediatric cadaveric tissue is extremely limited, a better understanding of MPFC and MQTFL anatomy will support surgeons in preoperative planning and intraoperative considerations for their approach to MQTFL and MPFL reconstruction. This may facilitate improved anatomic surgical stabilization of the patellofemoral joint in pediatric patients.

Anatomic Study of Anterior and Posterior Ankle Portal Sites for Ankle Arthroscopy in Plantarflexion and Dorsiflexion: A Cadaveric Study in the Japanese Population

Arthroscopy is an important and minimally invasive diagnostic and therapeutic tool. However, the risk of injury to the neurovascular structures around the portals exists during arthroscopy of the ankle. In the present study, we measured the distance between each portal and the adjacent neurovascular structures with the foot in plantarflexion and dorsiflexion in the Japanese population. Standard anterolateral (AL), anteromedial, posterolateral (PL), and posteromedial portal positions were identified in 6 fresh adult cadaveric feet. The skin was dissected from the underlying tissue to visualize the adjacent neurovascular structures as noninvasively as possible. The superficial peroneal nerve was the structure closest to an anterior (i.e., AL) portal (3.2 ± 4.2 and 8.3 ± 3.9 mm in plantarflexion and 5.2 ± 4.3 and 10.8 ± 4.1 mm in dorsiflexion), followed by the saphenous nerve and great saphenous vein (SpV). The distance from the superficial peroneal nerve to the AL portal and from the saphenous nerve and great SpV to the anteromedial portal increased significantly with dorsiflexion and decreased significantly with plantarflexion. The sural nerve was the structure closest to the posterior (i.e., PL) portal (10.4 ± 4.8 mm in plantarflexion and 8.5 ± 3.9 mm in dorsiflexion), followed by the lesser SpV. The distance from the sural nerve, saphenous nerve, and lesser SpV to the PL portal and from flexor hallucis longus, posterior tibial artery, and tibial nerve to the posteromedial portal increased significantly in plantarflexion and decreased significantly in dorsiflexion. These findings could help to prevent damage to the neurovascular structures during ankle arthroscopy.

Technique for Latex Injection and Reuse of Human Heads Preserved in Formaldehyde

Background  Understanding the anatomy of the skull base is paramount for every skull base surgeon, particularly in light of the expanded endoscopic endonasal approaches, and of the refined surgical technique used in both medial and lateral approaches. A comprehensive knowledge of anatomy is the cornerstone for a safe surgery, maximizing resection and minimizing complications. The best study method is the careful dissection of fresh human cadaveric heads in a well-equipped anatomy laboratory. In this study, we describe our protocol for preparing cadaveric specimens without vascular injection, which had been preserved in a formaldehyde solution after treating them with a dimethyldioctadecylammonium chloride/distearyl dimethyl ammonium chloride solution (commercial fabric softener) and injecting the vascular system with latex. Method  Six cadaveric specimens underwent our treatment and subsequent injection of the vascular system and dissection. Results  All specimens showed a good penetration of the latex and a clear improvement of the malleability of the tissues was noticed. The authors agree that this technique improved the quality of the head and facilitated studying. Conclusion  We consider this an effective treatment with latex, reaching small caliber vessels, and a greater malleability and flexibility of tissues, allowing better dissections, and greater anatomical exposure, making them suitable for skull base training, study, and research.

Variation in the Medial Patellofemoral Ligament Origin in the Skeletally Immature Knee: An Anatomic Study

BACKGROUND

The medial patellofemoral ligament (MPFL) is frequently reconstructed to treat recurrent patellar instability. The femoral origin of the MPFL is well described in adults but not in the skeletally immature knee.

PURPOSE

To identify a radiographic landmark for the femoral MPFL attachment in the skeletally immature knee and study its relationship to the distal femoral physis.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Thirty-six cadaveric specimens between 2 and 11 years old were dissected and examined (29 male and 7 female). Metallic markers were placed at the proximal and distal borders of the MPFL femoral origin footprint. Computed tomography scans with 0.625-mm slices in the axial, coronal, and sagittal planes were used to measure the maximum ossified height and ossified depth. The measurements were used to describe the position of the midpoint MPFL attachment with respect to the posterior-anterior and distal-proximal dimensions of the femoral condyle on the sagittal view and to describe the distance from the physis to the femoral origin of the MPFL.

RESULTS

In 23 of 36 specimens, the femoral origin of the MPFL was distal to the physis. Thirteen of the 36 specimens had an MPFL origin at or proximal to the physis, with a more proximal MPFL origin consistently seen in older specimens. The distance of the MPFL origin to the physis ranged from 15.1 mm distal to the physis to 8.3 mm proximal to the physis. The mean midpoint of the MPFL femoral origin was located 3.0 ± 5.5 mm distal to the physis for all specimens. For specimens aged <7 years, the mean MPFL origin was 4.7 mm distal to the physis, and for specimens aged ≥7 years, the mean MPFL origin was 0.8 mm proximal to the femoral physis. The MPFL origin was more proximal and anterior for those aged ≥7 years and more distal and posterior for those aged <7 years.

CONCLUSION

Surgical reconstruction of the MPFL is a common treatment to restore patellar stability. There appears to be significant variability in the origin of the MPFL in skeletally immature specimens. This study demonstrated that the MPFL origin was more proximal and anterior with respect to the physis in the older age group. The MPFL origin footprint may be customized for different age groups.

CLINICAL RELEVANCE

This information shows anatomic variation of the MPFL origin with age, with older specimens having a footprint that was more proximal and anterior than younger specimens. Customization of the surgical technique might be considered based on patient age.

The Effect of Hamstring Tendon Autograft Harvest on the Restoration of Knee Stability in the Setting of Concurrent Anterior Cruciate Ligament and Medial Collateral Ligament Injuries

BACKGROUND

A hamstring autograft is commonly used in anterior cruciate ligament (ACL) reconstruction (ACLR); however, there is evidence to suggest that the tendons harvested may contribute to medial knee instability.

HYPOTHESIS

We tested the hypothesis that the gracilis (G) and semitendinosus (ST) tendons significantly contribute to sagittal, coronal, and/or rotational knee stability in the setting of ACLR with a concurrent partial medial collateral ligament (MCL) injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve human cadaveric knees were subject to static forces applied to the tibia including an anterior-directed force as well as varus, valgus, and internal and external rotation moments to quantify laxity at 0°, 30°, 60°, and 90° of flexion. The following ligament conditions were tested on each specimen: (1) ACL intact/MCL intact, (2) ACL deficient/MCL intact, (3) ACL deficient/partial MCL injury, and (4) ACLR/partial MCL injury. To quantify the effect of muscle loads, the quadriceps, semimembranosus, biceps femoris, sartorius (SR), ST, and G muscles were subjected to static loads. The loads on the G, ST, and SR could be added or removed during various test conditions. For each ligament condition, the responses to loading and unloading the G/ST and SR were determined. Three-dimensional positional data of the tibia relative to the femur were recorded to determine tibiofemoral rotations and translations.

RESULTS

ACLR restored anterior stability regardless of whether static muscle loads were applied. There was no significant increase in valgus motion after ACL transection. However, when a partial MCL tear was added to the ACL injury, there was a 30% increase in valgus rotation ( P < .05). ACLR restored valgus stability toward that of the intact state when the G/ST muscles were loaded. A load on the SR muscle without a load on the G/ST muscles restored 19% of valgus rotation; however, it was still significantly less stable than the intact state.

CONCLUSION

After ACLR in knees with a concurrent partial MCL injury, the absence of loading on the G/ST did not significantly alter anterior stability. Simulated G/ST harvest did lead to increased valgus motion. These results may have important clinical implications and warrant further investigation to better outline the role of the medial hamstrings, particularly among patients with a concomitant ACL and MCL injury.

CLINICAL RELEVANCE

A concurrent ACL and MCL injury is a commonly encountered clinical problem. Knowledge regarding the implications of hamstring autograft harvest techniques on joint kinematics may help guide management decisions.

Ultrasound Accuracy of Liver Length Measurement with Cadaveric Specimens

The liver is one of the principal organs of our body involved in over 500 physiological functions related to metabolism, digestion, immunity, and storage of nutrients, which makes it an essential organ to preserve life. Given that there are a number of approaches to measure liver length through diagnostic 2D sonography, this work aims to determine the most accurate measurement of this organ. Cadaveric specimens (n = 21) were employed to assess measurements in midclavicular line (MCL) and midaxillary line (MAL). Each measurement was calculated in anteroposterior (AP) and craniocaudal (CC) planes. In addition, in situ measurements were obtained by accessing the organ through the anterior thoracoabdominal wall. Statistical differences were detected between MCL and MAL measurements (p < 0.05), a positive correlation between MAL CC and in situ anterior measurements were noted (r = 0.97). Liver size, as assessed through in situ measurements, varied as a funtion of BMI and waist circumference (p < 0.05). It is concluded that CC measurement of the RLL in MAL from the uppermost right hemi-diaphragm to the inferior tip of the right lobe through a horizontal line parallel to the anterior liver wall is the most accurate measurement of the organ by sonography.