The gracilis muscle and its use in clinical reconstruction: An anatomical, embryological, and radiological study

Body Mass Index Is Associated With Myocutaneous Free Flap Reliability: Overcoming the Obesity Obstacle With a Proposed Clinical Algorithm to Identify and Manage High-Risk Patients Undergoing Gracilis Free Flap With Skin Paddle Harvest

INTRODUCTION

The purpose of this study was to evaluate the role of body mass index (BMI) in predicting postoperative complications following myocutaneous free flap transfer. In addition, we sought to identify certain body composition variables that may be used to stratify patients into low- versus high-risk for gracilis myocutaneous free flap with skin paddle failure.

METHODS

Using the National Surgical Quality Improvement Program database, we collected data for all patients who underwent myocutaneous free flap transfer from 2015 to 2021. Demographic data, medical history, surgical characteristics, and postoperative outcomes, including complications, reoperations, and readmissions, were collected. Body mass index was correlated with outcome measures to determine its role in predicting myocutaneous free flap reliability. Subsequently, we retrospectively obtained measurements of perigracilis anatomy in patients who underwent computed tomography angiography bilateral lower extremity scans with intravenous contrast at our institution. We compared body composition data with mathematical equations calculating the potential area along the skin of the thigh within which the gracilis perforator may be found.

RESULTS

Across the United States, 1549 patients underwent myocutaneous free flap transfer over the 7-year study period. Being in obesity class III (BMI ≥40 kg/m2) was associated with a 4-times greater risk of flap complications necessitating a return to the operating room compared with being within the normal BMI range. In our computed tomography angiography analysis, average perigracilis adipose thickness was 18.3 ± 8.0 mm. Adipose thickness had a strong, positive exponential relationship with the area of skin within which the perforator may be found.

CONCLUSIONS

In our study, higher BMI was associated with decreased myocutaneous free flap reliability. Specifically, inner thigh adipose thickness can be used to estimate the area along the skin within which the gracilis perforator may be found. This variable, along with BMI, can be used to identify patients who are considered high-risk for flap failure and who may benefit from additional postoperative monitoring, such as the use of a color flow Doppler probe and more frequent and prolonged skin paddle monitoring.

An assessment of the variation of the intramuscular innervation of the gracilis muscle, with the aim of determining its neuromuscular compartments

Some muscles present neuromuscular compartments, one of which is the gracilis muscle. The aim of the present study is to determine the number of compartments present within the gracilis muscle based on its intramuscular innervation patterns; such knowledge could be of value in free functional muscle transfer. The study comprised 72 gracilis muscles (38 women, 34 men), fixed in 10% formalin solution. The muscles were removed and then stained using Sihler's method. When sufficient transparency was achieved, some measurements were made. Three different types of intramuscular innervation were distinguished. Type I (70.8%) was featured by at least one direct proximal nerve branch. Type II (23.6%) presented at least one indirect proximal nerve branch. Type III (5.6%) did not possess any proximal nerve branch. The median of descended nerve branches was five. Considerable anatomical variation is possible within the intramuscular innervation of the gracilis muscle. The muscle presents neuromuscular compartments, but the exact number depends on the type of its intramuscular innervation and the number of the main descendent nerve branches. All three types seem to be appropriate for free functional muscle transfer. Our findings may be of great value for surgeons carrying out complex reconstructions with the use of the gracilis muscle.

[Increasing Safety in Microsurgical Breast Reconstruction - Technique and Technology]

Microsurgical reconstruction has established itself as a standard procedure in breast reconstruction as it permits creation of a natural and aesthetically appealing breast mound, even after modified radical mastectomy and radiation. In the past few decades numerous new free flap donor-sites have been described that permit an individualized approach to reconstruction, thus, resulting in a high level of patient satisfaction. Paralleling these technical innovations, the focus of microsurgical breast reconstruction has shifted from mere "flap success" to "aesthetic outcome", while also taking into account the respective donor-site morbidity. Here, the authors discuss contemporary developments in the field with a particular focus on surgical techniques and technologies that contribute to increasing the safety of microsurgical breast reconstruction.

Preoperative imaging assessment of the paralytic upper limb

Imaging has become an essential tool in the study of the posttraumatic paralytic upper limb, in addition to the clinical examination and electroneuromyography. Upper extremity surgeons must be aware of how these different techniques contribute to the initial and preoperative assessment of nervous injuries. We review the appearance of traumatic nerve damage and muscle denervation during the initial injury assessment, focusing on the main aspects of brachial plexus injuries, paralysis after shoulder dislocation and traumatic damage to the radial nerve. Finally, we discuss the role of imaging for preoperative assessment of musculotendinous and osteoarticular palliative surgeries.

Forensic Implications of Anatomical Education and Surgical Training With Cadavers

Anatomical education and surgical training with cadavers are usually considered an appropriate method of teaching, above all for all surgeons at various levels. Indeed, in such a way they put into practice and exercise a procedure before performing it live, reducing the learning curve in a safe environment and the risks for the patients. Really, up to now it is not clear if the nonuse of the cadavers for anatomical education and surgical training can have also forensic implications. A substantial literature research was used for this review, based on PubMed and Web of Science database. From this review, it is clear that the cadaveric training could be considered mandatory, both for surgeons and for medical students, leading to a series of questions with forensic implications. Indeed, there are many evidences that a cadaver lab can improve the learning curve of a surgeon, above all in the first part of the curve, in which frequent and severe complications are possible. Consequently, a medical responsibility for residents and surgeons which perform a procedure without adequate training could be advised, but also for hospital, that has to guarantee a sufficient training for its surgeons and other specialists through cadaver labs. Surely, this type of training could help to improve the practical skills of surgeons working in small hospitals, where some procedures are rare. Cadaver studies can permit a better evaluation of safety and efficacy of new surgical devices by surgeons, avoiding using patients as ≪guinea pigs≫. Indeed, a legal responsibility for a surgeon and other specialists could exist in the use of a new device without an apparent regulatory oversight. For a good medical practice, the surgeons should communicate to the patient the unsure procedural risks, making sure the patients' full understanding about the novelty of the procedure and that they have used this technique on few, if any, patients before. Cadaver training could represent a shortcut in the standard training process, increasing both the surgeon learning curve and patient confidence. Forensic clinical anatomy can supervise and support all these aspects of the formation and of the use of cadaver training.

Free gracilis muscle transfer with ulnar nerve neurotization for elbow flexion restoration

PURPOSE

In upper and chronic brachial plexus injuries for which neurological surgery is not a good treatment option, one possibility for gaining elbow flexion is free functional muscle transfer. The primary aim of our study was to evaluate the elbow flexion gain achieved by free gracilis muscle transfer with partial ulnar nerve neurotization.

METHODS

This surgery was performed in 21 patients with upper and chronic (> 12 months) brachial plexus injuries. The level of injury, patient age, the time between trauma and surgery, the affected side, and the aetiology of the lesion were recorded. The primary outcome evaluated was elbow flexion muscle strength, which was measured using the British Medical Research Council (BMRC) scale, in patients with a minimum follow-up period of 12 months. The criterion used to classify elbow flexion as good was a grade of M4 or higher.

RESULTS

An M4 elbow flexion strength gain was observed in 61.9% of the patients. A gain of M2 or higher was observed in 95.2% of the patients. The mean range of active motion was 77° (range 10 minimum-110 maximum).

CONCLUSION

In patients with upper and chronic brachial plexus injuries, free gracilis muscle transfer with ulnar nerve neurotization yields a satisfactory gain in elbow flexion strength and is therefore a good treatment option.

Selecting a free flap for soft tissue coverage in lower extremity reconstruction

BACKGROUND

Goals of lower extremity microvascular reconstruction (LEMR) include the restoration of function, prevention of infection, and optimal cosmesis. Indications for LEMR include large defects that are not amenable to pedicled options, a large zone of injury, and large complex defects. The novice microsurgeon should first master a handful of free flaps to develop an armamentarium of options for addressing such defects. The scope of this review is to provide free flap options for LEMR in any of the thirds of the lower leg. After reading this article, the reader will understand variations, advantages, disadvantages, indications, and tips for raising each of these flaps.

METHODS

Six most commonly used free flaps for LEMR are described in this paper, including the anterolateral thigh flap (ALT) and its variations, the radial forearm flap (RFFF), the lateral arm flap (LAF), the gracilis muscle flap, the rectus abdominis flap (RAF) and the latissimus dorsi flap and its variations. Indications, advantages, disadvantages and technique tips are discussed for each flap. Moreover, selection of the recipient vessels, preoperative management along with an algorithm are also provided.

CONCLUSIONS

The ALT flap is a workhorse in covering defects of the leg, foot, and ankle. It's the flap of choice at our institution, especially given the number of traumatic wounds seen as a result of motor vehicles, all-terrain vehicles (ATV), lawnmowers, and gunshot wounds (GSW). At times, the lower extremity zone of injury requires a distant donor site. The RAF can also provide coverage for large soft tissue defects but donor-site morbidity remains its main drawback. The LAF and RFFF provide two pliable options, one that provides pliable soft tissue with minimal donor site morbidity and another that provides a long pedicle. The free gracilis flap is an excellent choice for crossing the ankle joint. Lastly, the free latissimus dorsi is indicated for large defects of the lower extremity independently of the location.

Quantitative and Neurovascular Anatomy of the Growing Gracilis Muscle in the Human Fetuses

This study is intended to obtain the algebraic growth dynamics of the gracilis in fetuses and determine the variations of neurovascular pedicle(s) of the gracilis, to aid infant surgeries. Forty fetuses (19 males and 21 females) were included in the study. Gestational mean age of the fetuses was 22.40 ± 2.67 (range, 18-28) weeks. Numerical values were obtained using a digital caliper and a digital image analysis software. Linear functions for the surface area, width, anterior, and posterior margin lengths of the gracilis were calculated, respectively, as: y = -289.307 + 20.501 × age (weeks), y = -7.113 + 0.622 × age (weeks), y = -24.421 + 3.434 × age (weeks), and y = -24.397 + 3.314 × age (weeks). In addition, length and width of the gracilis tendon were calculated as y = -6.676 + 0.934 × age (weeks) and y = -0.732 + 0.074 × age (weeks), respectively. Parameters of the gracilis had no statistically significant difference regarding side and sex (P > 0.05). In all the specimens, the gracilis was innervated by the anterior branch of the obturator nerve. Blood supply of the gracilis was identified to be derived from 1 single artery in 38 sides of total 80 (47.5%), from 2 arteries in 36 (45%) and from 3 arteries in 6 (7.5%). In 74 sides (92.5%), the nerve was superficial to the main artery, whereas in 6 sides (7.5%), it was deeper. The data of the present study could be beneficial for surgeons in infant surgeries to treat conditions such as obstetrical brachial plexus paralysis, facial palsy, or anal incontinence. Linear functions can be utilized to better evaluate the growth course of the gracilis in fetuses and to predict the dimensions thereof. Additionally, comprehending the structure and recognizing the variations of the gracilis nerves and arteries can help to protect the neurovascular pedicle(s) of the gracilis during the operations.

Radiological anatomy of the perforators of the gluteal region: The "radiosome" based anatomy

BACKGROUND

The superior (SGA) and the inferior gluteal artery (IGA) perforator flaps are widely used in pressure-sore repair and in breast reconstruction. The aim was to exhaustively depict the topographical anatomy of the whole system of perforators in the buttock.

METHODS

Eighty lower-extremity computed tomographic angiography (CTA) of patients (20 males/20 females, mean age 61-years old, range 38-81) were considered. The source artery, location, type, and caliber of gluteal perforators were analyzed. The location of perforators was reproduced using a standardized two-dimensional grid on the coronal plane, centered onto defined bone landmarks. We defined "radiosome" the cutaneous vascular territory of a source artery inferred through the representation of its whole perforator system at the exit point through the deep fascia.

RESULTS

A mean number of 25.6 ± 5.7 perforators in the gluteal region was observed, distributed as follows: 11.6 ± 4.8(45.2%) from SGA; 7.9 ± 4.5(30.8%) from IGA; 1.5 ± 0.8(5.8%) from fifth lumbar artery; 1.2 ± 0.8(4.7%) from internal pudendal artery; 1.2 ± 1(4.8%) from lateral circumflex femoral artery; 0.3 ± 0.7(1.2%) from circumflex iliac superficial artery. At least one large (internal diameter > 1 mm) SGA septocutaneous perforator was present in 77.5% of patients.

CONCLUSIONS

The gluteal region is vascularized by perforators of multiple source arteries. Septocutaneous perforators of SGA and IGA were planned along a curve drawn from the posterior-superior border of the iliac crest to the greater trochanter. The lumbar artery perforators are clustered over the apex of the iliac crest; the internal pudendal artery perforators are clustered medially to the ischiatic tuberosity. Contributions can also come from the sacral and superficial circumflex iliac arteries.

Anatomo-radiological patterns of pancreatic vascularization, with surgical implications: Clinical and anatomical study

The pancreas receives multiple arterial sources that should be considered in patients undergoing pancreatic surgery. The aim of this study is to describe pancreatic vascularization and to explore the anatomical basis of postoperative complications. Ten specimens from unembalmed cadavers, including the retroperitoneal vessels and organs and spleen, were injected with acrylic resins to obtain vascular casts. Thirty computed tomography angiographies (CTA) of subjects with no pancreatic pathology (mean age 70.9 years) were also analyzed. A paucivascular area at the neck of the pancreas was apparent in all vascular casts. At CTA: (1) the transverse pancreatic artery, the only artery running from the cervicocephalic to the somatocaudal segment, was visible in 76.9% of cases; (2) the splenic artery was suprapancreatic in 66.7% and intrapancreatic with a tortuous course in 33.3%; (3) the posterior superior pancreaticoduodenal artery was visible in 100% of cases, the anterior superior pancreatico-duodenal artery in 92.6%, the anterior inferior pancreaticoduodenal artery in 73.1%, the posterior inferior pancreaticoduodenal artery in 86.4%, the dorsal pancreatic artery in 65.4%, the great pancreatic artery in 73.1%, and the pancreatic arteries to the body and caudal pancreatic arteries in 96.2%. Our study demonstrated great individual variability of the pancreatic vasculature, which can be explored by CTA and could be relevant to surgical procedures. Clin. Anat. 30:614-624, 2017. © 2017 Wiley Periodicals, Inc.

The triangles of Grynfeltt and Petit and the lumbar tunnel: an anatomo-radiologic study

PURPOSE

Lumbar hernias are protrusions of intra-abdominal contents classically through the superior (Grynfeltt) and inferior (Petit) lumbar triangles. The anatomy of the triangles is variable and quantitative data are few. No radiological data on the anatomy of the triangles are available.

METHODS

Fifty computed tomography angiography of the upper abdomen (M25, F25, mean age 72.5-year-old) were analyzed. The dimensions and the contents of the lumbar triangles were analyzed. The characteristics of the space between the two triangles were also documented.

RESULTS

The superior lumbar triangle showed a mean surface area of 5.10 ± 2.6 cm². In the area of the triangle, the 12th intercostal pedicle and the 1st lumbar branches of the iliolumbar vessels were found in 42 and 46 %, respectively. The inferior lumbar triangle had a mean surface of area 18.7 ± 8.4 cm². In this area, the 2nd, 3rd, and 4th lumbar branches were found in 9, 67, and 8 %, respectively. On oblique coronal images, a direct tunnel between the superior and the inferior lumbar triangles was found, showing an oblique course, with a postero-anterior direction (mean length 36.5 ± 5.8 mm, mean caliber 7.4 ± 3.1 mm).

CONCLUSIONS

Among the anatomical factors of weakening of the abdominal wall, the course of branches of the lumbar vessels was documented not only in the superior but also in the inferior lumbar triangle. A real musculoaponeurotic tunnel between the superior and the inferior lumbar triangles located in the oblique coronal plane was found, that could play a role in the development of incarceration or strangulation of lumbar hernias.

Flow-through anastomosis using a T-shaped vascular pedicle for gracilis functioning free muscle transplantation in brachial plexus injury

OBJECTIVE

In gracilis functioning free muscle transplantation, the limited caliber of the dominant vascular pedicle increases the complexity of the anastomosis and the risk of vascular compromise. The purpose of this study was to characterize the results of using a T-shaped vascular pedicle for flow-through anastomosis in gracilis functioning free muscle transplantation for brachial plexus injury.

METHODS

The outcomes of patients with brachial plexus injury who received gracilis functioning free muscle transplantation with either conventional end-to-end anastomosis or flow-through anastomosis from 2005 to 2013 were retrospectively compared. In the flow-through group, the pedicle comprised a segment of the profunda femoris and the nutrient artery of the gracilis. The recipient artery was interposed by the T-shaped pedicle.

RESULTS

A total of 46 patients received flow-through anastomosis, and 25 patients received conventional end-to-end anastomosis. The surgical time was similar between the groups. The diameter of the arterial anastomosis in the flow-through group was significantly larger than that in the end-to-end group (3.87 mm vs. 2.06 mm, respectively, p<0.001), and there were significantly fewer cases of vascular compromise in the flow-through group (2 [4.35%] vs. 6 [24%], respectively, p=0.019). All flaps in the flow-through group survived, whereas 2 in the end-to-end group failed. Minimal donor-site morbidity was noted in both groups.

CONCLUSIONS

Flow-through anastomosis in gracilis functioning free muscle transplantation for brachial plexus injury can decrease the complexity of anastomosis, reduce the risk of flap loss, and allow for more variation in muscle placement.

Saving grace: distally pedicled gracilis muscular flap in lower limb salvage

During the 1970s, the incidence of limb amputation following surgery for sarcoma excision was as high as 50%. Two important developments have led to modern day limb salvage, namely chemotherapy and precision imaging techniques. We present a case of limb salvage in a patient with osteosarcoma plagued with recurrent infection after prosthetic revision. We discuss the use of the distally based pedicled gracilis muscular flap, which has little mention as a reconstructive option for defects around the knee.

Local and regional flaps for hand coverage

Hand surgeons are frequently challenged by the unique requirements of soft tissue coverage of the hand. Whereas many smaller soft tissue defects without involvement of deep structures are amenable to healing by secondary intention or skin grafting, larger lesions and those with exposed tendon, bone, or joint often require vascularized coverage that allows rapid healing without wound contraction. The purpose of this review was to present an overview of local and regional flaps commonly used for soft tissue reconstruction within the hand.

The gracilis myocutaneous free flap: a quantitative analysis of the fasciocutaneous blood supply and implications for autologous breast reconstruction

Background

Mastectomies are one of the most common surgical procedures in women of the developed world. The gracilis myocutaneous flap is favoured by many reconstructive surgeons due to the donor site profile and speed of dissection. The distal component of the longitudinal skin paddle of the gracilis myocutaneous flap is unreliable. This study quantifies the fasciocutaneous vascular territories of the gracilis flap and offers the potential to reconstruct breasts of all sizes.

Methods

Twenty-seven human cadaver dissections were performed and injected using lead oxide into the gracilis vascular pedicles, followed by radiographic studies to identify the muscular and fasciocutaneous perforator patterns. The vascular territories and choke zones were characterized quantitatively using the ‘Lymphatic Vessel Analysis Protocol’ (LVAP) plug-in for Image J® software.

Results

We found a step-wise decrease in the average vessel density from the upper to middle and lower thirds of both the gracilis muscle and the overlying skin paddle with a significantly higher average vessel density in the skin compared to the muscle. The average vessel width was greater in the muscle. Distal to the main pedicle, there were either one (7/27 cases), two (14/27 cases) or three (6/27 cases) minor pedicles. The gracilis angiosome was T-shaped and the maximum cutaneous vascular territory for the main and first minor pedicle was 35×19 cm and 34×10 cm, respectively.

Conclusion

Our findings support the concept that small volume breast reconstructions can be performed on suitable patients, based on septocutaneous perforators from the minor pedicle without the need to harvest any muscle, further reducing donor site morbidity. For large reconstructions, if a ‘T’ or tri-lobed flap with an extended vertical component is needed, it is important to establish if three territories are present. Flap reliability and size may be optimized following computed tomographic angiography and surgical delay.

Effects of additional gracilis tendon harvest on muscle torque, motor coordination, and knee laxity in ACL reconstruction

PURPOSE

To evaluate muscle torque, lower extremity coordination, and knee laxity after ACL reconstruction comparing patients operated on with semitendinosus graft (ST) and patients with combined semitendinosus and gracilis (STGR) grafts.

METHODS

Forty-six subjects who underwent ST (n = 23) or STGR harvest (n = 23) ACL reconstruction participated in this study. Quadriceps and hamstring torque were recorded using an isokinetic dynamometer. The anterior tibial translation was measured using the Kneelax 3 Arthrometer. The eccentric and concentric motor coordination was tested by multi-joint lower-limb tracking-trajectory test. All measurements were taken 12 months after surgery. Side-to-side differences were determined for all subjects.

RESULTS

Side-to-side differences in extensor peak torque at 180°/s and 60°/s did not differ between semitendinosus (ST) and semitendinosus + gracilis (STGR) groups (n.s.). However, side-to-side differences in flexor peak torque were significantly higher at 60°/s for the STGR group than the ST group (P = 0.002). Side-to-side differences in eccentric and concentric parts of tracking-trajectory test and anterior tibial translation did not differ between the STGR and the ST groups (n.s.).

CONCLUSION

The outcomes of this study suggested that additional harvest of gracilis did not influence lower extremity motor control, quadriceps muscle torque, and anterior tibial translation; however, it affected knee flexion isokinetic torque negatively at low angular velocity. This finding could be important for functional activity or sports with high demands on hamstring muscle strength. It is recommended that gracilis muscle should be preserved as possible during ACL reconstruction.

LEVEL OF EVIDENCE

Prospective comparative study, Level II.

Knee Region Coverage with Reversed Gracilis Pedicle Flap (GReSP Flap)

Introduction

To treat severe soft-tissue complications of total knee arthroplasty, we used an extended reversed gracilis flap based on secondary pedicles (the GReSP flap).

Step 1 Prepare Wound Bed

Locate the gracilis and pedicles, then debride the wound bed.

Step 2 Expose Gracilis Muscle

Expose the superficial aspect of the muscle, while protecting the saphenous vein and nerve.

Step 3 Check Muscle Perfusion

Temporarily clamp the main vascular pedicle to ensure blood supply when perfused only by the secondary pedicles.

Step 4 Mobilize Muscle Flap

Transect the proximal tendon of the gracilis muscle to provide maximal length for the muscle flap and ligate the main vascular and nerve pedicles.

Step 5 Cover with Skin Graft

Suture the flap in place and cover with skin graft.

Step 6 Postoperative Care

Immobilize the knee for two weeks; follow with rehabilitation to restore range of motion.

Results & Preop/Postop Images

We treated three patients who had an infection at the site of a total knee arthroplasty and exposure of the implant.

What to Watch For

IndicationsContraindicationsPitfalls & Challenges.

Body parts removed during surgery: a useful training source

Current undergraduate medical curricula provides relatively little time for cadaver dissection. The Department of Human Anatomy and Physiology at the University of Padova has organized a pilot project with the University Hospital for the donation of body parts that are surgically removed for therapeutic purposes and destined under Italian law for destruction. The aim of the project is to improve residents' practical training skills. A survey over the last two years has shown that about 60 body parts were available each year. These included 13 upper limbs or their parts (i.e., forearm with hand, hand, and fingers) and 47 lower limbs or their parts (i.e., legs with feet, feet, or toes). The residents explained the aim of the project to potential donors, and, if patients were willing to donate, their informed consent was obtained. The residents were present in the operating theater during the surgical procedure. In the post-operative phase, the same residents performed dissections on the body part(s), following a teaching schedule prepared by a clinical anatomist, who also assisted residents during their studies. Residents also acted as tutors for undergraduate medical students who attended these dissections. The underlying pathology for which the body part was removed was examined, and surgical procedures were practiced on the body part itself. Our project provided an opportunity for a close relationship between anatomists and surgeons, reinforcing core knowledge of anatomy by appreciation of its clinical importance. The active involvement of residents as learners and as teachers in the various steps of this project improved their knowledge of surgical techniques and helped to establish a sense of ethical responsibility and respect for the human body. This approach involves study of anatomical structures from new perspectives and leads to improved surgical practice.

The transversely split gracilis twin free flaps

The gracilis muscle is a Class II muscle that is often used in free tissue transfer. The muscle has multiple secondary pedicles, of which the first one is the most consistent in terms of position and calibre. Each pedicle can support a segment of the muscle thus yielding multiple small flaps from a single, long muscle. Although it has often been split longitudinally along the fascicles of its nerve for functional transfer, it has rarely been split transversely to yield multiple muscle flaps that can be used to cover multiple wounds in one patient without subjecting him/her to the morbidity of multiple donor areas.

Autobionics: a new paradigm in regenerative medicine and surgery

The concept of bionics was developed 50 years ago and represented the development of engineering and technology based on natural biological systems. Traditional applications of bionics in healthcare include artificial bionic organs that apply engineering principles to replace or augment physiological functions by integrating electronic, mechanical or electromechanical components to inherent body tissues/organs (we term this as 'exobionics'). Recently, there has been a new wave of bio-inspired treatments that act through the reorganization of the existing biological organs in an individual to enhance physiology. Here, the technology does not replace biological tissue, but rather applies engineering principles to replace or augment physiological functions by the rearrangement and manipulation of inherent tissue/organs; we term this autobionics. Examples include: dynamic cardiomyoplasty (artificial heart pump using skeletal muscle), the Ross procedure (pulmonary autograft), dynamic graciloplasty (artificial sphincter) and metabolic gastric bypass (rearranging the gastrointestinal tract to modify gut- and pancreatic-hormone release). Autobionic therapies can be classified into dynamic, static and metabolic procedures. This results in tissue redesignation (one tissue used in place of another), tissue replacement and systems reorganization (rearranging inherent organ/tissue anatomy). In some cases autobionic procedures can enhance physiological function beyond normality and represents a new era in bio-inspired versatility.