Active nerve management for above the knee amputation: A comparison of through the wound versus posterior approach.

Targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI) are used to prevent or treat neuromas in amputees. TMR for above-the-knee amputation (AKA) is most commonly performed through a posterior incision rather than the stump wound because recipient motor nerves are primarily located in the proximal third of the thigh. When preventative TMR is performed with concurrent AKA, a posterior approach requires intraoperative repositioning and an additional incision. The purpose of this study was to evaluate feasibility of TMR and operative times for nerve management performed through the wound compared to a posterior approach in AKA patients to guide surgical decision-making. Patients who underwent AKA with TMR between 2018-2023 were reviewed. Patients were divided into two groups: TMR performed through the wound (Group I) and TMR performed through a posterior approach (Group II). If a nerve was unable to undergo coaptation for TMR due to the lack of suitable donor motor nerves, RPNI was performed. Eighteen patients underwent AKA with nerve management were included from Group I (8 patients) and Group II (10 patients). TMR coaptations performed on distinct nerves was 1.5 ± 0.5 in Group I compared to 2.6 ± 0.5 in Group II (p = 0.001). Operative time for Group I was 200.7 ± 33.4 min compared to 326.5 ± 37.1 min in Group II (p = 0.001). TMR performed through the wound following AKA requires less operative time than a posterior approach. However, since recipient motor nerves are not consistently found near the stump, RPNI may be required with TMR whereas the posterior approach allows for more TMR coaptations.

Botox in below knee amputation for the management of post-operative contracture: a systematic review.

During the 1970s, scientists first used botulinum toxin to treat strabismus. While testing on monkeys, they noticed that the toxin could also reduce wrinkles in the glabella area. This led to its widespread use in both medical and cosmetic fields. The objective of the study was to evaluate the potential use of Botox in managing post-operative contracture after below-knee amputation. We conducted a systematic review In Pubmed, Cochrane Library, Embase, and Google Scholar using the MESH terms Botox, botulinum toxin, post-operative contracture, amputation, and below knee amputation. Our goal was to evaluate the potential use of Botox to manage post-operative contracture in patients who have undergone below-knee amputation. Our findings show evidence in the literature that Botox can effectively manage stump hyperhidrosis, phantom pain, and jumping stump, but no clinical trial has been found that discusses the use of Botox for post-operative contracture. Botox has been used in different ways to manage spasticity. Further studies and clinical trials are needed to support the use of Botox to manage this complication.

[Bionic Surgery Meets Bionic Reconstruction - First In-human use of Robotic Microsurgery in Targeted Muscle Reinnervation]. / Bionische Chirurgie trifft Bionische Rekonstruktion ­ erstes in-human Projekt von robotischer Mikrochirurgie zur Targeted Muscle Reinnervation.

Robotic microsurgery is an emerging field in reconstructive surgery, which provides benefits such as improved precision, optimal ergonomics, and reduced tremors. However, only a few robotic platforms are available for performing microsurgical procedures, and successful nerve coaptation is still a challenge. Targeted muscle reinnervation (TMR) is an innovative reconstructive procedure that rewires multiple nerves to remnant stump muscles, thereby reducing neuroma and phantom limb pain and improving the control of bionic prostheses. The precision of surgical techniques is critical in reducing axonal sprouting around the coaptation site to minimise the potential for neuroma formation. This study reports the first use of a microsurgical robotic platform for multiple nerve transfers in a patient undergoing TMR for bionic extremity reconstruction. The Symani robotic platform, combined with external microscope magnification, was successfully used, and precise handling of nerve tissue and coaptation was easily feasible even in anatomically challenging environments. While the precision and stability offered by robotic assistance may be especially useful for nerve surgery, the high economic costs of robotic microsurgery remain a major challenge for current healthcare systems. In conclusion, this study demonstrated the feasibility of using a robotic microsurgical platform for nerve surgery and transfers, where precise handling of tissue is crucial and limited space is available. Future studies will explore the full potential of robotic microsurgery in the future.

[Prosthetic Fitting Concepts after Major Amputation in the Upper Limb - an Overview of Current Possibilities]. / Prothetische Versorgungskonzepte nach Majoramputation der oberen Extremität ­ eine Übersicht gegenwärtiger Möglichkeiten.

BACKGROUND: The upper extremity and particularly the hands are crucial for patients in interacting with their environment, therefore amputations or severe damage with loss of hand function significantly impact their quality of life. In cases where biological reconstruction is not feasible or does not lead to sufficient success, bionic reconstruction plays a key role in patient care. Classical myoelectric prostheses are controlled using two signals derived from surface electrodes in the area of the stump muscles. Prosthesis control, especially in high amputations, is then limited and cumbersome. The surgical technique of Targeted Muscle Reinnervation (TMR) offers an innovative solution: The major arm nerves that have lost their target organs due to amputation are rerouted to muscles in the stump area. This enables the establishment of cognitive control signals that allow significantly improved prosthesis control. PATIENTS/MATERIALS AND METHODS: A selective literature review on TMR and bionic reconstruction was conducted, incorporating relevant articles and discussing them considering the clinical experience of our research group. Additionally, a clinical case is presented. RESULTS: Bionic reconstruction combined with Targeted Muscle Reinnervation enables intuitive prosthetic control with simultaneous movement of various prosthetic degrees of freedom and the treatment of neuroma and phantom limb pain. Long-term success requires a high level of patient compliance and intensive signal training during the prosthetic rehabilitation phase. Despite technological advances, challenges persist, especially in enhancing signal transmission and integrating natural sensory feedback into bionic prostheses. CONCLUSION: TMR surgery represents a significant advancement in the bionic care of amputees. Employing selective nerve transfers for signal multiplication and amplification, opens up possibilities for improving myoelectric prosthesis function and thus enhancing patient care. Advances in the area of external prosthetic components, improvements in the skeletal connection due to osseointegration and more fluid signal transmission using wireless, fully implanted electrode systems will lead to significant progress in bionic reconstruction, both in terms of precision of movement and embodiment.

Targeted Muscle Reinnervation at the Time of Amputation Decreases Recurrent Symptomatic Neuroma Formation.

BACKGROUND: Targeted muscle reinnervation (TMR) is an effective technique for the prevention and management of phantom limb pain (PLP) and residual limb pain (RLP) among amputees. The purpose of this study was to evaluate symptomatic neuroma recurrence and neuropathic pain outcomes between cohorts undergoing TMR at the time of amputation (ie, acute) versus TMR following symptomatic neuroma formation (ie, delayed). METHODS: A cross-sectional, retrospective chart review was conducted using patients undergoing TMR between 2015 and 2020. Symptomatic neuroma recurrence and surgical complications were collected. A subanalysis was conducted for patients who completed Patient-Reported Outcome Measurement Information System (PROMIS) pain intensity, interference, and behavior scales and an 11-point numeric rating scale (NRS) form. RESULTS: A total of 105 limbs from 103 patients were identified, with 73 acute TMR limbs and 32 delayed TMR limbs. Nineteen percent of the delayed TMR group had symptomatic neuromas recur in the distribution of original TMR compared with 1% of the acute TMR group ( P < 0.05). Pain surveys were completed at final follow-up by 85% of patients in the acute TMR group and 69% of patients in the delayed TMR group. Of this subanalysis, acute TMR patients reported significantly lower PLP PROMIS pain interference ( P < 0.05), RLP PROMIS pain intensity ( P < 0.05), and RLP PROMIS pain interference ( P < 0.05) scores in comparison to the delayed group. CONCLUSIONS: Patients who underwent acute TMR reported improved pain scores and a decreased rate of neuroma formation compared with TMR performed in a delayed fashion. These results highlight the promising role of TMR in the prevention of neuropathic pain and neuroma formation at the time of amputation. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Internal Iliac Artery Patency as a Predictor of Above-Knee Amputation Stump Healing.

BACKGROUND: The primary aim of this study was to assess the role of internal iliac patency in predicting outcomes of above-knee amputation (AKA) stump healing. The secondary objectives were to assess the accuracy of Wound, Ischemia, and Foot Infection (WIfI) classification system in predicting AKA stump healing and its association with delayed mortality. METHODS: This is a retrospective study performed in a vascular surgery unit in a tertiary hospital on patients who underwent AKAs over 1 year, from July 2021 until June 2022. Patient demographic data, WIfI scoring, outcome of AKAs, and patency of profunda femoris and internal iliac artery (IIA) were collected. To minimize confounding, a single vascular surgeon performed all computed tomography imaging reviews and arterial measurements. Approval for this study was obtained from the National Research Registry, NMRR ID-23-01865-KQ4 (investigator initiated research). RESULTS: Ninety patients underwent AKA over 1 year, from July 2021 until June 2022. Occluded IIA in the presence of patent profunda femoris did not affect the wound healing of the AKA stump. There was significant association between WIfI scoring and mortality. Patients with a WIfI scoring of 3 to 4 were observed to have a higher mortality rate compared with patients with normal healing: 47 (72.0%) vs. 4 (80.0%); P = 0.021. CONCLUSIONS: In this study, the IIA patency shows no statistically significant effect on AKA stump healing; however, the small number of patients is a drawback of the study. This study also demonstrates that the WIfI score can be a prognostic factor for mortality in patients undergoing AKA.

[The surgical treatment of peripheral neuromas]. / De chirurgische behandeling van perifere neuromen.

Peripheral neuromas are a prevalent problem following nerve injury or certain surgical interventions like limb amputation. It is important to consider a peripheral neuroma when a patient experiences pain in the innervation area of a peripheral sensory or mixed nerve (branch), especially following trauma or amputation. Adequate recognition of a painful neuroma is crucial to treat patients satisfactorily for their invalidating and chronic symptoms. We want to emphasize that surgical intervention can be an effective and permanent treatment for symptomatic neuromas. The standard surgical treatment is neuroma excision and burying of the nerve stump in adjacent muscle. However, there is a shift towards new and active techniques like Targeted Muscle Reinnervation, of which future comparative research will have to demonstrate whether it is more effective in treating peripheral neuroma pain than conventional surgery.

[The surgical treatment of peripheral neuromas]. / De chirurgische behandeling van perifere neuromen.

Peripheral neuromas are a prevalent problem following nerve injury or certain surgical interventions like limb amputation. It is important to consider a peripheral neuroma when a patient experiences pain in the innervation area of a peripheral sensory or mixed nerve (branch), especially following trauma or amputation. Adequate recognition of a painful neuroma is crucial to treat patients satisfactorily for their invalidating and chronic symptoms. We want to emphasize that surgical intervention can be an effective and permanent treatment for symptomatic neuromas. The standard surgical treatment is neuroma excision and burying of the nerve stump in adjacent muscle. However, there is a shift towards new and active techniques like Targeted Muscle Reinnervation, of which future comparative research will have to demonstrate whether it is more effective in treating peripheral neuroma pain than conventional surgery.

Update on Upper Limb Neuroma Management.

Painful terminal neuromas in the upper limb due to nerve injury are common. Neuroma symptoms include a sharp and burning sensation, cold intolerance, dysesthesia, pain, numbness, and paresthesia. These symptoms could have a negative impact on the functional ability of the patient and quality of life. In addition, Prostheses use might be abandoned by amputees due to neuroma-induced pain. Many clinicians face challenges while managing neuromas. Contemporary "active" methods like regenerative peripheral nerve interface (RPNI), targeted muscle reinnervation (TMR), and processed nerve allograft repair (PNA) are replacing the conventional "passive" approaches such as excision, transposition, and implantation techniques. RPNI involves inducing axonal sprouting by transplanting the free end of a peripheral nerve into a free muscle graft. TMR includes reassigning the role of the peripheral nerve by the transfer of the distal end of a pure sensory or a mixed peripheral nerve to a motor nerve of a nearby muscle segment. To give the peripheral nerve a pathway to re-innervate its target tissue, PNA entails implanting a sterile extracellular matrix prepared from decellularized and regenerated human nerve tissue with preserved epineurium and fascicles. Of these, RPNI and TMR appear to hold a promising treatment for nerve-ending neuromas and prevent their relapse. In contrast, PNA may reduce neuroma pain and allow meaningful nerve repair. The aim of this article is to provide an overview of the newer approaches of TMR, RPNI, and PNA and discuss their implications, surgical techniques, and reported consequences.

Treatment of Lymphorrhea Associated with an Amputation Stump with Lymphaticovenular Anastomosis.

Lower limb lymphorrhea is a condition with a considerable impact on the quality of life. It is usually associated with inguinal lymph node dissection and vascular procedures with femoral exposure. In this case report, we describe a patient who underwent a below-knee amputation and two years later developed lymphorrhea from the stump, preventing adaptation to the prosthesis. Lymphoscintigraphy showed a delayed lymphatic progression. After failure of conservative treatment, she underwent lymphaticovenular anastomosis with a successful outcome. Drainage cessation suggests that lymphaticovenular anastomosis may be an effective treatment for patients with lymphorrhea from and amputation stump, although further studies are required to determine long-term efficacy.

A linforreia do membro inferior é uma patologia com grande impacto na qualidade de vida. Está geralmente associada a esvaziamentos ganglionares inguinais e a procedimentos vasculares com exposição dos vasos femorais. Apresentamos o caso de uma doente que sofreu uma amputação abaixo do joelho e dois anos depois desenvolveu linforreia a partir do coto de amputação, impedindo a adaptação à prótese. A linfocintigrafia revelou um atraso na progressão linfática. Após falência do tratamento conservador, foi submetida a anastomoses linfático-venosas, com resolução da linforreia. A cessação da drenagem sugere que a realização de anastomoses linfático-venosas poderá ser um tratamento eficaz em doentes com inforreia a partir de um coto de amputação, embora sejam necessários mais estudos para determinar a sua eficácia a longo prazo.

Feasibility of Magnetic Resonance-Guided High-Intensity-Focused Ultrasound (MRgHIFU) Ablation of Stump Neuromas for the Relief of Chronic Postamputation Neuropathic Pain.

Up to 70% of limb amputees develop chronic postamputation neuropathic pain (CPANP) which includes phantom pain and residual limb neuropathic pain due to neuroma formation. CPANP often requires invasive procedures aimed at neuroma ablation. Five amputees received 6 noninvasive magnetic resonance-guided high-intensity-focused ultrasound MRgHIFU treatments ExAblate®, Insightec, Tirat-Carmel, Israel). Although ablative temperature (>65°C) at the neuroma was reached in only 1 patient, pain intensity dropped from 5.7 at baseline to 4.3 and back to 5.6 at 3 and 6 month follow-up. Post-treatment bone necrosis was demonstrated in 1 patient. Although no firm conclusion about the effectiveness of MRgHIFU for CPANP could be drawn, further studies are warranted.

Estimating the Impact of Postamputation Pain.

BACKGROUND: Neuromas, neuralgia, and phantom limb pain commonly occur after lower-extremity amputations; however, incidence of these issues is poorly reported and understood. Present literature is limited to small cohort studies of amputees, and the reported incidence of chronic pain after amputation ranges as widely as 0% to 80%. We sought to objectively investigate the incidence of postamputation pain and nerve-related complications after lower-extremity amputation. METHODS: Patients who underwent lower-extremity amputation between 2007 and 2017 were identified using a national insurance-based claims database. Incidence of reporting of postoperative neuroma, neuralgia, and phantom limb pain were identified. Patient demographics and comorbidities were assessed. Average costs of treatment were determined in the year after lower-extremity amputation. Logistic regression analyses and resulting odds ratios were calculated to determine statistically significant increases in incidence of postamputation nerve-related pain complications in the setting of demographic factors and comorbidities. RESULTS: There were 29,507 lower amputations identified. Postoperative neuralgia occurred in 4.4% of all amputations, neuromas in 0.4%, and phantom limb pain in 10.9%. Nerve-related pain complications were most common in through knee amputations (20.3%) and below knee amputations (16.7%). Male sex, Charlson Comorbidity Index > 3, diabetes mellitus, diabetic neuropathy, diabetic angiopathy, diabetic retinopathy, obesity, peripheral vascular disease, and tobacco abuse were associated with statistically significant increases in incidence of 1-year nerve-related pain or phantom limb pain. CONCLUSIONS: Given the incidence of these complications after operative extremity amputations and associated increased treatment costs, future research regarding their pathophysiology, treatment, and prevention would be beneficial to both patients and providers.

[Amputations of fingers and the hand]. / Amputationen an den Fingern und der Hand.

Revision amputation, ray amputation and narrowing of the hand can be indicated for pathological alterations of fingers and thumbs due to traumatic, inflammatory or vascular causes but also for functional deficits regarding mobility, sensibility, perfusion, and/or pain. Surgical amputation is considered if reconstructive options are no longer possible, not desired and are no longer meaningful with respect to effort and risks. Patients need to be informed about the expected deficits in function and esthetic appearance due to the amputation in advance. On the other hand, surgical amputations represent a good treatment option, for which the duration of treatment and scope are well estimated. Therefore, they are good options for patients with comorbidities, with concerns about extensive reconstructive surgery and with limited compliance. It is essential to respect anatomical and functional aspects to guarantee favorable surgical results and avoid complications, which might compromise the function of the hand beyond that which is unavoidable. The most frequent complications after creating a stump or ray resection are persistent pain, unstable skin and soft tissue conditions, mobility disorders, disturbing stumps without function, uncontrolled growth of nail remnants and recurrent inflammation.

[Functional rehabilitation after transfemoral amputation : Shaft prosthesis or endo-exo prosthesis?] / Funktionelle Rehabilitation nach Oberschenkelamputation : Schaftprothese oder Endo-Exo-Prothese?

BACKGROUND: After transfemoral amputation a prosthesis is required to restore autonomous standing and bipedal locomotion. Attachment of the prosthesis can be achieved either classically via socket suspension with a shaft in the stump or directly via implantation of an intramedullary transcutaneous femoral prosthesis (osseointegrated prosthesis). AIM: A fully instrumented gait analysis should enable objectification of the anticipated advantages of the EEP with respect to the gait pattern and individual mobility. MATERIAL AND METHODS: In two patients with a unilateral transfemoral amputation a comprehensive gait analysis was carried out prior to and 6 months (patient 1) or 11 and 20 months (patient 2) after switching from a socket prosthesis to an EEP. This was carried out in the Gait Realtime Analysis Interactive Lab (GRAIL), a fully instrumented gait laboratory with virtual reality and enables assessment close to the conditions of daily life. RESULTS: In both cases the gait analysis confirmed the advantages associated with an EEP for the transmission of force to the prosthesis and the accompanying improvement in gait symmetry.

Impact of N-Acetyl-Cysteine on Ischemic Stumps Following Major Lower Extremity Amputation: A Pilot Randomized Clinical Trial.

OBJECTIVE: To evaluate the impact of N-acetyl-cysteine (NAC) on amputation stump perfusion and healing in patients with critical limb-threatening ischemia (CLTI). BACKGROUND: Patients with CLTI are at increased risk of poor amputation site healing leading to increased procedure-associated morbidity. METHODS: In a pilot, double-blind, placebo-controlled, randomized controlled trial, patients with CLTI undergoing major elective lower extremity amputation were randomized 1:1 to intravenous NAC (1200 mg twice-daily) or placebo for up to 5 days postoperatively. Primary outcomes were change in stump perfusion at postoperative day 3 (POD3) and POD5, and healing at POD30. Stumps were serially evaluated for wound healing, and tissue perfusion was evaluated using noninvasive laser-assisted fluorescent angiography. RESULTS: Thirty-three patients were randomized to NAC (n = 16) or placebo (n = 17). Thirty-one patients were eligible for intent-to-treat analysis (NAC14; placebo17). Twenty patients (NAC7; placebo13) had amputation stump perfusion defects at POD0 and were considered high-risk for poor healing. Intent-to-treat analysis revealed no significant differences between treatment groups. Subgroup analysis of high-risk patients revealed differences in stump perfusion defect size (NAC-0.53-fold, placebo +0.71-fold; 95% confidence interval -2.11 to-0.35; P < 0.05) and healing (NAC [100%], placebo [46%]; P < 0.01) between study treatments. CONCLUSIONS: Postoperative NAC administration may improve amputation stump perfusion and healing in patients with CLTI and tissue perfusion defects at the time of amputation. Intraoperative laser-assisted fluorescent angiogra-phy may help surgeons identify high-risk patients with stump perfusion defects and provide early adjunctive interventions. Future studies can further explore the therapeutic benefits of NAC in the healing and perfusion of other surgical operative sites in high-risk individuals. TRIAL REGISTRATION: clinicaltrials.gov, Identifier: NCT03253328.

[Targeted muscle reinnervation and targeted sensory reinnervation : Role of complex neurotization after amputation]. / "Targeted muscle reinnervation" und "targeted sensory reinnervation" : Rolle komplexer Neurotisationen nach Amputation.

In association with major amputations of the upper and lower extremities, surgical procedures with nerve transfer are increasingly being introduced. In order to examine the value of these procedures the currently available data were analyzed and related to the corresponding insights from conventional amputation surgery as well as confirmed aspects of microsurgery of peripheral nerves. Mainly retrospective observations of low case numbers and sometimes individually different surgical approaches can be found. Risk analysis and sufficient long-term follow-up periods are lacking as well as comparisons with appropriate control groups. The published results on operative procedures with selected nerve transfers after or during amputation do not currently allow any conclusions about the advantages. Systematic influences in the assessment of the results are probable. Implementation of these treatment options outside controlled clinical trials cannot be recommended.

Techniques to prevent symptomatic neuroma in digital amputations.

The occurrence of a symptomatic neuroma on a digital amputation stump, whether traumatic or not, is a frequent complication that affects the patient's quality of life. The objective of this study was to analyze the complications inherent to the various techniques used to manage the nerves when performing digital amputation. We compared different surgical nerve management techniques to determine if one technique is more effective than another in preventing neuroma occurrence. We reviewed 105 patients over a 5-year period. A DN4 score greater than 4 and the modified Tinel test (percussion) showing a trigger zone allowed us to clinically diagnose symptomatic neuroma-related pain. We found 23 symptomatic neuromas out of 131 digital amputations. Twelve neuromas were found when the nerves had been neglected (12/33), eight were found in nerves treated by stripping (8/60), three when nerves were treated by stripping and thermal ablation (3/18). No neuroma was found in the five cases of centrocentral union of the two proper palmar digital nerves, in the 5 nerves buried in the bone or in the 9 nerves subjected to thermal ablation only. Management of the nerve is essential for the prevention of neuromas in digital amputations. New techniques such as bone burial and centrocentral union of the two stumps appear to be particularly effective.

Challenges and Potential in Targeted Muscle Reinnervation in Pediatric Amputees.

Targeted muscle reinnervation (TMR) is a powerful new tool in preventing and treating residual limb and phantom limb pain. In the adult population, TMR is rapidly becoming standard of care; however, there is a paucity of literature regarding indications and outcomes of TMR in the pediatric population. We present 2 cases of pediatric patients who sustained amputations and the relevant challenges associated with TMR in their cases. One is a 7-year-old patient who developed severe phantom and residual limb pain after a posttraumatic above-knee amputation. He failed pharmacologic measures and underwent TMR. He obtained complete relief of his symptoms and is continuing to do well 1.5 years postoperatively. The other is a 2-year-old boy with bilateral wrist and below-knee amputations as sequelae of sepsis. TMR was not performed because the patient never demonstrated evidence of phantom limb pain or symptomatic neuroma formation. We use these 2 cases to explore the challenges particular to pediatric patients when considering treatment with TMR, including capacity to report pain, risks of anesthesia, and cortical plasticity. These issues will be critical in determining how TMR will be applied to pediatric patients.

Utilization of Techniques for Upper Extremity Amputation Neuroma Treatment and Prevention.

This study aimed to understand the current utilization of surgical approaches for nerve ending management in upper extremity amputation to prevent and treat nerve-related pain. We administered a survey to 190 of 1270 surgeons contacted by email (15% response rate) and analyzed their demographics, practice patterns, and perceptions regarding techniques for nerve ending management in upper extremity amputees. Although many surgical techniques were employed, most surgeons (54%) performed traction neurectomy during amputation and, alternatively, bury nerve into muscle if a neuroma subsequently develops (52%). Surgeons in practice less than 10 years were more likely to perform targeted muscle reinnervation (TMR) and regenerative peripheral nerve interfaces (RPNI) than surgeons in practice greater than 10 years (p<0.001). TMR and RPNI were performed more frequently for proximal amputations than distal amputations, but there is no consensus regarding the optimal timing to utilize these techniques. Surgeons commonly cited improved prosthetic control, pain, and phantom limb symptoms as reasons for performing TMR and RPNI. Increased physician compensation as a consideration was more commonly cited among TMR non-adopter than adopters (31% vs 14%, p=0.008). There is no consensus regarding techniques for the prevention or treatment of nerve ending pain in upper extremity amputees. TMR and RPNI are being utilized with increasing frequency and both patient and surgeon factors affect implementation in clinical practice.