An in-vitro three-dimensional surgical simulation technique to predict tibial tunnel length in transtibial posterior cruciate ligament reconstruction.

BACKGROUND: During the transtibial posterior cruciate ligament (PCL) reconstruction, drilling depth excessively longer than the tibial tunnel length (TTL) is an important reason to cause popliteal neurovascular bundle injury when preparing the tibial tunnel. This study aims to develop an in-vitro three-dimensional surgical simulation technique to determine the TTL in anteromedial (AM) and anterolateral (AL) approaches. METHODS: A total of 63 knees' 3-dimensional (3D) computed tomography models were included in this study. The SuperImage system was used to reconstruct the 3D knee model and locate the tibial PCL site. The established 3D knee model and the coordinates of the tibial PCL site were imported into Rhinoceros 3D modeling software to simulate AM and AL tibial tunnel approaches with different tibial tunnel angles (TTA). The TTL and the tibial tunnel height (TTH) were measured in this study. RESULTS: In AM and AL tibial tunnel approaches, the TTL showed a strong correlation with the TTA (for AM: r = 0.758, p < 0.001; for AL: r = 0.727, p < 0.001). The best fit equation to calculate the TTL based on the TTA was Y = 1.04X + 14.96 for males in AM approach, Y = 0.93X + 17.76 for males in AL approach, Y = 0.92X + 14.4 for females in AM approach, and Y = 0.94X + 10.5 for females in AL approach. CONCLUSION: Marking the TTL on the guide pin or reamer could help to avoid the drill bit over-penetrated into the popliteal space to damage the neurovascular structure.

Anatomical Structures at Risk in Percutaneous Preparation Talonavicular Fusion.

BACKGROUND: The stability of the hindfoot greatly relies on the integrity of the talonavicular joint. Pathologies affecting this joint often necessitate fusion. Our study explores the risks posed to neurovascular and tendon structures during simulated percutaneous talonavicular joint preparation for fusion. METHODS: In 9 fresh cadaver specimens, the talonavicular joint was accessed through two portals. A 2-mm Shannon burr was employed for joint surface preparation with distraction provided by a pin-based distractor. Dissections were performed to assess potential damage to critical structures, including the dorsalis pedis artery, superficial and deep peroneal nerves, extensor hallucis longus (EHL), and tibialis anterior (TA) tendons. RESULTS: The dorsal portal site was found to be significantly closer to important structures compared to the medial portal site. The Shannon burr made contact with various structures, with a single transection identified for both deep and superficial peroneal nerve branches. During the dorsal portal site approach, potential injury to the EHL tendon was identified as concern. CONCLUSION: This study sheds light on the potential risks associated with percutaneous dorsal and medial joint preparation approaches using a Shannon burr.Level of Evidence:Level V, mechanism-based reasoning..

Medially and distally inserted tuberosity screw fixation of the osteotomized tubercle is safe and effective in retro-tubercular bi-planar opening-wedge high tibial osteotomy.

PURPOSE: The purpose of this study was to develop a safe and effective method of inserting one tuberosity screw and to determine whether retro-tubercular (RT)-Open-wedge high tibial osteotomy (OWHTO) with tuberosity screw fixation can be conducted to overcome the problem of osteotomized tubercle and produce favorable outcomes compared to RT-OWHTO without tuberosity screw fixation. METHODS: From 2018 to 2020, patients who underwent bi-planar RT-OWHTO were allocated as two groups (RT-OWHTO without tuberosity screw fixation as group I and with screw fixation as group II). Computed tomography (CT) was used to analyze osteotomy configurations such as RT gap and tip distance, and union of the main and second plane osteotomy sites. The RT gap distance was measured as the length of the osteotomy gap. The RT tip distance was measured as the length of the gap at the tip of the tibial tubercle. Post-operative complications were analyzed also. To evaluate the neurovascular (NV) approximity of screw fixation group, the pre-operative magnetic resonance imaging (MRI) images were referenced on the post-operative CT for the assessment of the safe zone. RESULTS: In total, 44 knees in group I and 46 knees in group II were enrolled. The RT gap distance (2.58 ± 0.69 mm vs. 0.57 ± 0.57 mm; p < .001) and RT tip distance (4.31 ± 1.60 mm vs. 1.48 ± 1.42 mm; p < .001) were significantly larger in group I than in group II. The sum of union grade in the second plane osteotomy site (17.93 ± 2.18 points vs. 22.24 ± 2.57 points; p < .001) was statistically different between two groups at three months post operatively. Post-operative tuberosity prominence occurred in five knees only in group I (p = 0.025), although tibial tuberosity fracture developed in seven cases in group II compared with two cases in group I with no statistical significance. NV was safe when the screw was inserted medially. CONCLUSION: RT-OWTHO with one-screw fixation for the tuberosity was effective in terms of tuberosity prominence and the union of the second plane osteotomy site. However, it also produced another problem, such as tuberosity fracture. In addition, a tuberosity screw was safe when it was inserted in the medial-distal direction. LEVEL OF EVIDENCE: Cohort study; level III.

A Study of Anatomical Variations of Sphenoid Sinus on CT PNS: Our Experience.

Sphenoid sinus anatomical variations are very common, its prior knowledge is very essential while doing skull base surgery to avoid catastrophic complications which might be due to damage of surrounding neurovascular structures. This retrospective observational study was done to examine the different anatomical variations of sphenoid sinus on CT PNS which was conducted in KMCH, Katihar from May 2019 to April 2020 involving 60 cases above 15 years of age who had undergone CT PNS. Sellar type of pneumatization was seen in 66.7%, pterygoid process pneumatization was seen in 25%. Single septation was present in 43.3%, septum attached to optic nerve was seen in 33.3%, onodi cell was seen in 36.7%, anterior clinoid process pneumatization was seen in 13.3% of cases. By this study we came to a conclusion that preoperative assessment of sphenoid sinus anatomy and its variations is mandatory to avoid surrounding neurovascular structure damage and CSF leak.

The injection site in the tarsal tunnel to minimize neurovascular injury for heel pain: an anatomical study.

INTRODUCTION: The aim of this study was to investigate the location and distribution patterns of neurovascular structures and determine the effective injection point in the tarsal tunnel for heel pain. METHODS: Fifteen adult non-embalmed cadavers with a mean age of 71.5 years were studied. The most inferior point of the medial malleolus of the tibia (MM) and the tuberosity of the calcaneus (TC) were identified before dissection. A line connecting the MM and TC was used as a reference line. The reference point was expressed in absolute distance along the reference line using the MM as the starting point. For measurements using MRI, the depth from the skin was measured to inferior at an interval of 1 cm from the MM. RESULTS: The posterior tibial artery, lateral plantar nerve, and medial plantar nerve were located from 29.0 to 37.3% of the reference line from the MM. The distribution frequencies of the medial calcaneal nerve on the reference line from the MM were 0%, 8.60%, 37.15%, 37.15%, and 17.10%, respectively. The mean depth of the neurovascular structures was 0.3 cm. DISCUSSION: This study recommended an effective injection site from 45.0 to 80.0% of the reference line.

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.

Pregnane X Receptor Deletion Modifies Recognition Memory and Electroencephalographic Activity.

Nuclear receptors (NR) are emerging as key players in the central nervous system (CNS) with reported implications in physiological and pathophysiological conditions. While a number of NR has been studied, it is unknown whether invalidation of the pregnane xenobiotic receptor (PXR, NR1I2) corresponds to neurological modifications in the adult brain. PXR-/- C57BL/6J and wild-type mice were used to investigate: (i) recognition memory, motor coordination, and anxiety-like behaviors; (ii) longitudinal video-electroencephalographic (EEG) recordings and frequency wave analysis; (iii) neurovascular structures by histological evaluation and expression of the cerebrovascular tight junctions ZO1 and CLDN5. Absence of PXR was associated with anxiety-like behavior and recognition memory impairment in adult mice. The latter was simultaneous to an EEG signature of lower theta frequency during sleep and abnormal delta waves. Neurophysiological changes did not correspond to significant structural changes in the adult brain, expect for a localized and minor increase in the fronto-parietal neurovascular density and reduced ZO1, but not CLDN5, expression in isolated brain capillaries. Our results converge with existing evidence supporting a link between NR expression and brain physiology. Although the exact modalities remain to be elucidated, the possibility that extra-physiological modulation of PXR may constitute a pathophysiological entry point or a molecular target for brain diseases is proposed.

The neurovascular structures in the triangular space of the upper limb: an anatomical study / Las estructuras neurovasculares en el espacio triangular del miembro superior: un estudio anatómico

The aim of this study was to investigate the neuromuscular distribution after passing through the triangular space of the shoulder. Thirty-five specimens from 18 adult Korean cadavers (12 males and 6 females, age ranging from 42-102 years) were used in the study. This study analyzed the order in which the artery entered the muscle from that point the artery passed through the triangular space. The incidence of the first branch of the circumflex scapular artery was 11.4 % for infraspinatus, 5.7 % for teres major, 25.7 % for teres minor, 20.1 % for long head of biceps brachii, 25.7 % for subscapularis, and 11.4 % for subcutaneous tissue. This study investigated the incidence of lack of blood supply from the artery in the triangular space. This incidence was 27.8 % for infraspinatus, 13.0 % for teres major, 5.6 % for teres minor, 38.8 % for long head of triceps brachii, and 14.8 % for subscapularis. Four specimens showed arterial distribution in all surrounding muscles. One specimen identified the nerve branch to innervate teres minor of triangular space of shoulder. The results of this study will be helpful in clinical practice.

El objetivo de este estudio fue investigar la distribución neuromuscular después de pasar a través del espacio triangular del hombro. Para el estudio fueron utilizados treinta y cinco especímenes de 18 cadáveres adultos coreanos (12 varones y 6 mujeres, con una edad de 42-102 años). Se analizó el orden en que la arteria penetra en el músculo y continúa a través del espacio triangular. La incidencia de la primera rama de la arteria circunfleja escapular fue: 11,4 % en el músculo infraspinoso, 5,7 % en el músculo redondo mayor, 25,7 % en el músculo redondo menor, 20,1% en la cabeza larga del músculo bíceps braquial, 25,7 % en el músculo subescapular y 11,4 % en el tejido subcutáneo. Este estudio investigó la incidencia de la falta de suministro de sangre de la arteria en el espacio triangular. Se observó incidencia de 27,8 % para el músculo infraespinoso, 13,0 % para el músculo redondo mayor, 5,6 % para el músculo redondo menor, 38,8 %, para la cabeza larga del músculo tríceps braquial y 14,8 % para el músculo subescapular. Cuatro especímenes mostraron distribución arterial en todos los músculos circundantes. En un caso se identificó la rama nerviosa para el músculo redondo menor en espacio triangular del hombro. Los resultados de este estudio serán útiles en anatomía clínica.