- Email: [email protected]
Objective sensory and functional outcomes at the donor site following endoscopic-assisted sural nerve harvest
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Journal of Plastic, Reconstructive & Aesthetic Surgery (2017) xx, 1e7
Objective sensory and functional outcomes at the donor site following endoscopic-assisted sural nerve harvest Daniel P. Butler*, Kavan S. Johal, Catherine E. Wicks, Adriaan O. Grobbelaar Department of Plastic and Reconstructive Surgery, The Royal Free Hospital, Pond Street, London NW3 2QG, UK Received 21 November 2016; accepted 17 February 2017
KEYWORDS Sural nerve; Nerve graft; Donor site; Outcome
Summary Background: The sural nerve is a common choice for a nerve graft. Understanding the potential morbidity associated with its harvest is important. In this study, we describe the objective sensory and functional outcomes associated with endoscopic sural nerve harvest from a combined paediatric and adult population. Methods: Data were collected prospectively from patients attending for follow-up between August 2015 and January 2016, who had previously undergone an endoscopic sural nerve graft harvest. Sensory loss was evaluated using a 5.07 Semmes-Weinstein monofilament. The lower extremity functional scale was used to evaluate the patients’ lower limb function. Statistical comparison was made using the Student’s t-test. Results: The outcomes from 46 sural nerve grafts were evaluated. The mean age of the patients was 18.1 years (range 4e45 years old). The mean time since surgery was 4.3 years. Those aged 18 years had a significantly smaller area of sensory loss (p Z 0.003), which was not related to a difference in foot size. Those who had undergone surgery >6 months previously had a significantly smaller area of sensory loss than those who had undergone surgery <6 months ago (p Z 0.0002). The mean lower extremity functional scale score was 78.7/80. Conclusion: We demonstrated a significantly reduced post-harvest sensory deficit among a paediatric population compared to that seen in adults. Furthermore, sensory loss reduces with time. Despite the sensory loss resulting from sural nerve graft harvest, there is minimal loss of function. As such, the sural nerve continues to be an excellent donor for a nerve graft procedure. Crown Copyright ª 2017 Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons. All rights reserved.
* Corresponding author. Department of Plastic and Reconstructive Surgery, The Royal Free Hospital, Pond Street, London NW3 2QG, UK. E-mail address: [email protected] (D.P. Butler). http://dx.doi.org/10.1016/j.bjps.2017.02.022 1748-6815/Crown Copyright ª 2017 Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons. All rights reserved. Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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Introduction Nerve grafts serve a number of reconstructive purposes ranging from post-traumatic defects to serve as adjuncts in facial reanimation surgery. A common donor nerve is the sural nerve in the lower leg as it provides a long graft length and ease of harvest.1 A further suggested benefit is the minimal donor site morbidity experienced by the patient.2e11 The sural nerve is most commonly formed from the medial sural cutaneous nerve arising from the tibial nerve and a peroneal communicating branch that can arise from the lateral sural cutaneous nerve or the common peroneal nerve directly.12 However, in 27% of cadaveric dissections, the anatomy differed, and five separate variants have been described.12 The function of the sural nerve is purely sensory, supplying a territory over the posterolateral lower limb and lateral aspect of the foot. Given the frequency with which the sural nerve is utilised as a donor nerve, a detailed understanding of the morbidity associated with its harvest is important. The existing literature has demonstrated that sensory loss reduces with time and that morbidity associated with pain, cold intolerance and hypersensitivity are minimal.3e9,13 Many, however, have made this evaluation using nonvalidated patient questionnaires.3,5,7,8 Furthermore, a comparison between outcomes in a paediatric and an adult population has not been made. Finally, an assessment of the outcomes associated with endoscopic sural nerve harvest has not been reported. In this study, we describe the objective sensory, morbidity and functional outcomes associated with endoscopic-assisted sural nerve harvest from a combined paediatric and adult population.
Materials and methods Data were collected prospectively from consecutive patients attending for follow-up between August 2015 and January 2016 who had undergone a sural nerve graft as part of a twostage facial reanimation procedure. For inclusion in the study, patients must have undergone sural nerve harvest using a minimally invasive technique introduced in the department in 2006. Patients were excluded if nerve graft harvest had been <6 months previously, if there had been any other previous surgery to the leg or if they had a systemic disease that could affect the neurological function. Data in five key domains were collected during routine follow-up outpatient clinical appointments, comprising both clinician- and patient-reported outcomes.
Patient and surgical features The first section gathered information on patient demographics, assessment date, surgical site (right or left) and date of nerve harvest.
Sensory loss The loss of sensation was established using a SemmesWeinstein monofilament examination.14 A 5.07/10 g
D.P. Butler et al. Semmes-Weinstein monofilament was chosen, as adult studies have demonstrated that inability to sense touch at this calibre suggests a loss of protective sensation in the foot.15,16 However, no existing studies demonstrate the appropriate Semmes-Weinstein monofilament to evaluate protective sensation in a paediatric population. Lapid et al.9 demonstrated in a control paediatric population that 100% of the volunteers could sense a 3.61 Semmes-Weinstein monofilament or less. Therefore, it was believed that using a 5.07 Semmes-Weinstein in the paediatric patients included in this study was appropriate, given this calibre produces more load on the skin and, in the instance of normal foot sensation, should be felt by the child. After removing the patient’s shoes and socks and ensuring the lower leg was exposed, the patient was asked to respond positively (‘yes’) when they felt the monofilament press against their skin. A demonstration was performed on the patient’s arm prior to commencing the sensory examination of the leg. All patients were instructed to keep their eyes closed throughout the examination. The tip of the monofilament was pressed against the skin until the filament buckled and was then held there for 1 s. An area of sensory loss was mapped out along the lateral aspect of the foot and lower leg. The length and height of this identified area were used to calculate the total area of sensory loss. In children, intermittent testing of the medial aspect of the foot was confirmed so that they were continuing to produce reliable results during the sensory examination.
Pain Patients were asked to use a visual analogue scale of 0 (no pain) to 10 (severe pain) to ascertain pain related to the nerve donor site at the time of review.
Scar The patient’s Fitzpatrick skin type and length of both proximal and distal scars were recorded. The quality of the scarring was assessed using the Patient and Observer Scar Assessment scale.17
Function Lower limb function was assessed using the lower extremity functional scale.18 This score contains 20 patient-reported questions that assess the patient’s ability to perform everyday activities involving the lower limbs. A maximum score of 80 is possible, with a lower score demonstrating a reduced level of function. This score was chosen considering the excellent testeretest reliability and the responsiveness previously demonstrated.19
Surgical technique All nerve graft harvests were performed by the senior surgeon (A.O.G.). A minimally invasive sural nerve graft harvest technique was used,20 and all harvested nerves were used as a cross-facial nerve graft during a first-stage facial
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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Outcomes following sural nerve harvest reanimation procedure. This technique has been standard practice in our department since 2006. Graft harvest was performed with the patient in the supine position under tourniquet control. Access to the sural nerve is made through a vertical incision posterior to the lateral malleolus (Figure 1). The distal nerve is isolated from the surrounding subcutaneous tissue and dissected distally under direct vision as far as possible and then transected. Gentle traction is placed on the distal end of the nerve graft, and proximal dissection is then performed under direct vision. Once proximal dissection can proceed no further, a separate horizontal posterior calf incision is planned at the junction of the proximal and middle third of the calf. The horizontal incision is planned by identifying the point where distal traction on the nerve can be palpated through the skin. After making the skin incision, blunt dissection is used to identify the sural nerve, which is usually deep to the investing fascia of the lower leg and lying between the two bellies of gastrocnemius. Again, proximal and distal dissection of the nerve under is performed direct vision. At this stage, an endoscopic nerve hook is carefully passed along the length of the nerve to identify any points of fixation or additional branches. If gentle traction on the sural nerve through the proximal wound is unable to deliver the nerve graft, then the VascuClear endoscopic vessel harvesting scope (Sorin, USA) is introduced into the distal wound, and any fascial adhesions or nerve branches are divided under direct vision using Endoshears(Covidien, USA). The nerve is then delivered into the proximal wound and transected as far proximal as possible under direct external vision. A graft of 20e30 cm is typically obtained depending on the size of the patient (Figure 2). The proximal stump is buried between the gastrocnemius muscle bellies. Wound closure is performed using interrupted 3-0 Monocryl(Ethicon, USA) deep dermal sutures and a continuous 3-0 Prolene(Ethicon, USA) sub-cuticular suture, which is removed 12e14 days post-operatively.
Statistical analysis Statistical comparison between groups was made using a Student’s t-test, with a p-value of <0.05 considered to be a statistically significant result. Where descriptive data presentation is used, the mean, standard deviation (SD) and
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Figure 2 An intra-operative photograph demonstrating a 20cm section of the nerve harvested from a paediatric patient.
standard error of the mean (SEM) are shown. Statistical data were processed using the 2016 GraphPad Prism Software (GraphPad Software, Inc., California, USA).
Results A total of 40 patients were identified during the study period, incorporating 46 sural nerve grafts harvested for cross facial nerve grafting procedures. Of those, 19 patients were male and 21 were female. The mean age of patients at surgery was 18.1 years with a range of 4e45 years. A total of 28 nerve grafts were harvested from the left leg and 18 from the right leg. The mean time since surgery was 4.3 years (range 0.5e9 years).
Sensory loss
Figure 1 An intra-operative photograph demonstrating the two incisions used to access the sural nerve during endoscopic harvest.
Among the entire study population, the mean area of sensory loss measured using the 5.07 Semmes-Weinstein monofilament was 45.4 cm2 (SD Z 50.4 cm2, SEM Z 7.4 cm2). Five patients had no demonstrable sensory loss. Patients were initially grouped into those aged 18 years (n Z 30) and those aged >18 years (n Z 16). Those aged 18 years had a significantly smaller area of sensory loss (p Z 0.003, Figure 3). A similar trend was found when
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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grouping patients into those aged 10 (n Z 23) and >10 years (n Z 23), although this did not reach statistical significance (p Z 0.06, Figure 3). To determine whether the significant difference in the area of sensory loss between those aged 18 and >18 years is due in part to a smaller foot size in the younger of these two patient groups, a separate comparison of those aged 0e8 years (n Z 16) with those aged 9e18 years (n Z 14) was made. No significant difference was found in the area of sensory loss (p Z 0.43, Figure 3). When evaluating the effect of time since surgery on the area of sensory loss, it was shown that those who had undergone surgery 6 months previously (n Z 8) had a significantly larger area of sensory loss than those who had undergone surgery >6 months ago (n Z 38) (p Z 0.0002, Figure 4).
Pain Pain scores were found to be very low with a mean average visual analogue pain score of 0.2 among the study population (SD Z 0.6, SEM Z 0.08). The maximum pain score given from any patient in the study group was 3 out of 10.
Scarring The mean average scar length was 2.8 cm (SD Z 0.9, SEM Z 0.1) for the proximal wound and 4.1 cm (SD Z 1.0, SEM Z 0.2) for the distal wound. The mean average patient-rated scar score was 9.1/60 (SD Z 6.7, SEM Z 1.0) and 9.8/50 (SD Z 5.8, SEM Z 0.9) for the observer-rated scar score. A score of six and five were considered to represent normal skin for the patient and observer-rated scar score, respectively.
Function According to the lower extremity functional scale, minimal effect on function was found with a group mean average score of 78.74 out of a maximum of 80 (SD Z 4.13, 80
SEM Z 0.61). No significant differences in function were observed when comparing patients according to age at the time of surgery and time since surgery (Figure 5).
Discussion This present study has shown that endoscopic-assisted sural nerve grafting is associated with minimal pain and good scarring outcomes. In addition, patients of all ages in our study had excellent post-operative function, according to the lower extremity functional scale. Our results also add to the body of evidence that the area of sensory loss following sural nerve graft harvest reduces with time. This is in keeping with other studies published on this subject (Table 1). Aszmann et al. suggested that this was as a result of sprouting from adjacent nerves.13 They also found that sensory recovery began as early as 3 weeks post-operatively and that upon performing an anaesthetic block of the adjacent named sensory nerves, the area of sensory loss returned to that seen postoperatively. Given that patients who underwent surgery before the age of 18 showed significantly reduced areas of sensory loss, there must be additional factors that contribute to the improved sensation demonstrated during prolonged follow-up. It may be that cortical re-mapping and cerebral plasticity in the paediatric brain account for this finding.4,21 Despite the occasionally large areas of sensory loss demonstrated in this study, the associated functional limitations are minimal. This is in keeping with studies that have demonstrated that loss of sural nerve function has little effect on postural stability and joint proprioception during activities that would be classified as activities of normal daily living.22,23 Mazzella and McMillan, however, demonstrated a considerable reduction in postural stability when standing on the non-dominant leg following a sural nerve block,22 and others have found a discernible change in patient gait following graft harvest.24 This could, therefore, have implications for athletes and those with pre-existing impairment of the contralateral leg. Currently
74.8
AREA OF SENSORY LOSS (CM²)
70 59
60 50 40 30
29.6
31.7
34.7 23.9
20 10 0 ≤18 years old >18 years old ≤10 years old >10 years old ≤8 years old 9-18 years old AGE GROUP
Figure 3
A graph to demonstrate the area of sensory loss according to grouped age.
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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Outcomes following sural nerve harvest
5
120 101.6
AREA OF SENSORY LOSS (CM²)
100 80 60 40
33.6
20 0 6 months ago
>6 months ago TIME SINCE SURGERY
Figure 4
A graph to demonstrate the effect of time since surgery on the area of measurable sensory loss.
LOWER EXTREMITY FUNCTIONAL SCALE SCORE (MAX=80)
90 80
79.4
77.4
79.3
78.3
≤2 years since surgery
>2 years since surgery
70 60 50 40 30 20 10 0 ≤18 years old
Figure 5
>18 years old
A graph to demonstrate the effect of age at surgery and time since surgery on post-operative function.
available lower limb functional scores, such as that used in this study, are unlikely to be sensitive enough to detect such a limitation. As such, careful consultation should be had with each individual patient to identify the future demands required of each potential donor limb. Comparing the area of sensory loss associated with different sural nerve harvest techniques is not possible because of the different measurement methods used. It is unlikely, however, that altering the harvest technique will alter the associated sensory loss as all techniques have the ultimate aim of removing the sural nerve. The effect of incision length and direction associated with different harvesting techniques on sensory loss is unclear and cannot be established from this study. In addition to the minimal functional limitation occurring after sural nerve harvest, our patient population showed very low post-operative pain scores. Similarly low
levels have been observed in previous studies, which have also noted that cold intolerance and hypersensitivity are uncommon after the removal of the sural nerve.2e6,8 The combination of low post-operative pain and minimal functional deficit supports the ongoing use of the sural nerve as a common source for a nerve graft. Harvesting the nerve through an endoscopic-assisted approach serves to minimise the scars associated with harvest, and our study has shown excellent patient- and observer-rated scar scores. Other minimally invasive techniques exist for harvesting the sural nerve, such as using a tendon or nerve stripper passed from the distal to the proximal wound.8,25 We believe that the benefit of directly visualising the dissection of the nerve in areas of adhesion under endoscopic vision aids to minimise the risk of iatrogenic injury to the nerve,25,26 which in the context of a cross-facial nerve graft procedure would necessitate harvest of the
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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Overview of sensory changes reported in previous studies on sural nerve graft harvest.
Study
Population
Indication for graft
Length of graft
Harvest technique
Data collection
Donor sensory loss?
Sensory recovery with time?
This study
Mixed (n Z 46)
Cross facial nerve graft
20e30 cm
Endoscopic
Yes
Yes
Aszmann 199613
Adults (n Z 3)
Not specified
Not specified
Not specified
Yes
Yes
Not specified Peripheral nerve defect repair
Not specified “Whole length”
Sensory evaluation in clinic e SemmesWeinstein Sensory evaluation in clinic e Pressure Specifying Sensory Device Telephone questionnaire Postal questionnaire
Not specified 54% e multiple stab incisions 15% e single longitudinal incision 31% e not specified Not specified Postal questionnaire
Yes Yes
Yes Yes
Yes
Yes
18e20 cm
Minimal access using tendon stripper
Not reported Not reported
Not specified
Not specified
Ehretsman 19994 Mixed (n Z 16) Hallgren 20132 Mixed (n Z 41)
Adults (n Z 29)
Lapid 20079
Peripheral nerve defect repair Adults (n Z 12) Radical prostatectomy nerve defect reconstruction Children (n Z 14) Brachial plexus surgery
Martins 20127
Mixed (n Z 40)
Miloro 20053 Ng 20066
Kim 20018
Not specified
Varied according to requirement
Single longitudinal incision
Adults (n Z 26)
Brachial plexus surgery and peripheral nerve defects Trigeminal nerve repair
2.5e4 cm
Adults (n Z 20)
Not specified
Not specified
Single longitudinal incision Single longitudinal incision
Patient reported outcome in clinic e McGill pain questionnaire Sensory evaluation in clinic e SemmesWeinstein Sensory evaluation in clinic e light brush sensation Telephone questionnaire Sensory evaluation in clinic e pin prick
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Ijpma 20065
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Yes
Not tested
Yes
Yes
Yes
Yes
Yes
Yes
D.P. Butler et al.
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
Table 1
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Outcomes following sural nerve harvest contralateral sural nerve and result in additional scarring. Our technique is similar to that described by Capek in 1996.20 Where required, the length of the nerve harvested can be extended by the addition of a third transverse incision in the popliteal fossa.27 Other authors have modified the technique to simply perform a stab incision to divide the nerve proximally28 or to harvest the nerve through one distal incision at the lateral malleolus alone.29,30 In our experience, the time to harvest the sural nerve using the endoscopic-assisted technique is equivalent to the multi-incision open approach. A standard endoscopy stack can be used in combination with the single-use Vascuclear and Endoshear equipment. The excellent scar outcomes shown in this study support the use of a minimally invasive approach despite the additional cost of the disposable endoscopic equipment. Our study is the first to report the objective sensory and functional outcomes associated with endoscopic-assisted sural nerve graft harvest. Furthermore, we have demonstrated a significantly reduced post-harvest sensory deficit among a paediatric population compared to that seen in adults. Despite the sensory loss resulting from sural nerve graft harvest, there is minimal loss of function. As such, the sural nerve continues to be an excellent donor for a nerve graft procedure.
Conflicts of interest statement No conflicts of interest to declare.
Financial disclosure statement No funding given towards this study.
References 1. Sunderland S, Ray LJ. The selection and use of autografts for bridging gaps in injured nerves. Brain 1947;70(1):75e92. 2. Hallgren A, Bjo ¨rkman A, Chemnitz A, Dahlin LB. Subjective outcome related to donor site morbidity after sural nerve graft harvesting: a survey in 41 patients. BMC Surg 2013 Sep 24;13: 39. 3. Miloro M, Stoner JA. Subjective outcomes following sural nerve harvest. J Oral Maxillofac Surg 2005 Aug;63(8):1150e4. 4. Ehretsman RL, Novak CB, Mackinnon SE. Subjective recovery of nerve graft donor site. Ann Plast Surg 1999 Dec;43(6):606e12. 5. IJpma FF, Nicolai JP, Meek MF. Sural nerve donor-site morbidity: thirty-four years of follow-up. Ann Plast Surg 2006 Oct;57(4):391e5. 6. Ng SS, Kwan MK, Ahmad TS. Quantitative and qualitative evaluation of sural nerve graft donor site. Med J Malays 2006 Dec;61:13e7. 7. Martins RS, Barbosa RA, Siqueira MG, et al. Morbidity following sural nerve harvesting: a prospective study. Clin Neurol Neurosurg 2012 Oct;114(8):1149e52. 8. Kim ED, Seo JT. Minimally invasive technique for sural nerve harvesting: technical description and follow-up. Urology 2001 May;57(5):921e4.
7 9. Lapid O, Ho ES, Goia C, Clarke HM. Evaluation of the sensory deficit after sural nerve harvesting in pediatric patients. Plast Reconstr Surg 2007 Feb;119(2):670e4. 10. Kumar S, Jacob J. Variability in the extent of sensory deficit after sural nerve biopsy. Neurol India 2004 Dec;52(4):436e8. 11. Poburski R, Malin JP, Stark E. Sequelae of sural nerve biopsies. Clin Neurol Neurosurg 1985;87(3):193e8. 12. Riedl O, Frey M. Anatomy of the sural nerve: cadaver study and literature review. Plast Reconstr Surg 2013 Apr;131(4): 802e10. 13. Aszmann OC, Muse V, Dellon AL. Evidence in support of collateral sprouting after sensory nerve resection. Ann Plast Surg 1996;37:520e5. 14. Weinstein S. Fifty years of somatosensory research: from the semmes-Weinstein monofilaments to the Weinstein enhanced sensory test. J Hand Ther 1993;6:11e22. 15. Feng Y, Schlosser FJ, Sumpio BE. The Semmes Weinstein monofilament examination as a screening tool for diabetic peripheral neuropathy. J Vasc Surg 2009;50(3):675e82. 16. Jeng C, Michelson J, Mizel M. Sensory thresholds of normal human feet. Foot Ankle Int 2000;21:501e4. 17. Draaijers LJ, Tempelman FR, Botman YA, et al. The patient and observer scar assessment scale: a reliable and feasible tool for scar evaluation. Plast Reconstr Surg 2004 Jun;113(7):1960e5. 18. Binkley JM, Stratford PW, Lott SA, Riddle DL. The lower extremity functional scale (LEFS): scale development, measurement properties, and clinical application. North American orthopaedic rehabilitation research network. Phys Ther 1999 Apr;79(4):371e83. 19. Mehta SP, Fulton A, Quach C, Thistle M, Toledo C, Evans NA. Measurement properties of the lower extremity functional scale: a systematic review. J Orthop Sports Phys Ther 2016 Jan 26:1e39 [Epub ahead of print]. 20. Capek L, Clarke HM, Zuker RM. Endoscopic sural nerve harvest in the pediatric patient. Plast Reconstr Surg 1996 Oct;98(5): 884e8. 21. Johnston MV. Brain plasticity in paediatric neurology. Eur J Paediatr Neurol 2003;7(3):105e13. 22. Mazzella NL, McMillan AM. Contribution of the sural nerve to postural stability and cutaneous sensation of the lower limb. Foot Ankle Int 2015 Apr;36(4):450e6. 23. Rein S, Fabian T, Krishnan K, et al. Evaluation of the proprioceptive influence of the cutaneous afferents to the ankle in patients after sural nerve harvesting. Neurosurgery 2009 Mar; 64(3):519e25. 24. Yavuzer R, Yavuzer G, Ergin S, Latifoglu O. Gait analysis: a new perspective on sural nerve graft donor site morbidity assessment. Ann Plast Surg 2002;48(4):449e50. 25. Hassanpour E, Yavari M, Karbalaeikhani A, Saremi H. Nerve stripper-assisted sural nerve harvest. J Neurol Surg A Cent Eur Neurosurg 2014;75(2):161e4. 26. Jaroszynski G, Johnston GH. Harvesting of the sural nerve with a tendon stripper. Microsurgery 1996;17(4):217e20. 27. Capek L, Clarke HM. Endoscopically assisted sural nerve harvest in infants. Semin Plast Surg 2008;22(1):25e8. 28. Spinks TJ, Adelson PD. Pediatric sural nerve harvest: a fully endoscopic technique. Neurosurgery 2009 May;64:360e3. 29. Park SB, Cheshier S, Michaels D, Murovic JA, Kim DH. Endoscopic harvesting of the sural nerve graft: technical note. Neurosurgery 2006;58(Suppl. 1). ONS-E180. 30. Hadlock TA, Cheney ML. Single-incision endoscopic sural nerve harvest for cross face nerve grafting. J Reconstr Microsurg 2008;24(7):519e23.
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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Journal of Plastic, Reconstructive & Aesthetic Surgery (2017) xx, 1e7
Objective sensory and functional outcomes at the donor site following endoscopic-assisted sural nerve harvest Daniel P. Butler*, Kavan S. Johal, Catherine E. Wicks, Adriaan O. Grobbelaar Department of Plastic and Reconstructive Surgery, The Royal Free Hospital, Pond Street, London NW3 2QG, UK Received 21 November 2016; accepted 17 February 2017
KEYWORDS Sural nerve; Nerve graft; Donor site; Outcome
Summary Background: The sural nerve is a common choice for a nerve graft. Understanding the potential morbidity associated with its harvest is important. In this study, we describe the objective sensory and functional outcomes associated with endoscopic sural nerve harvest from a combined paediatric and adult population. Methods: Data were collected prospectively from patients attending for follow-up between August 2015 and January 2016, who had previously undergone an endoscopic sural nerve graft harvest. Sensory loss was evaluated using a 5.07 Semmes-Weinstein monofilament. The lower extremity functional scale was used to evaluate the patients’ lower limb function. Statistical comparison was made using the Student’s t-test. Results: The outcomes from 46 sural nerve grafts were evaluated. The mean age of the patients was 18.1 years (range 4e45 years old). The mean time since surgery was 4.3 years. Those aged 18 years had a significantly smaller area of sensory loss (p Z 0.003), which was not related to a difference in foot size. Those who had undergone surgery >6 months previously had a significantly smaller area of sensory loss than those who had undergone surgery <6 months ago (p Z 0.0002). The mean lower extremity functional scale score was 78.7/80. Conclusion: We demonstrated a significantly reduced post-harvest sensory deficit among a paediatric population compared to that seen in adults. Furthermore, sensory loss reduces with time. Despite the sensory loss resulting from sural nerve graft harvest, there is minimal loss of function. As such, the sural nerve continues to be an excellent donor for a nerve graft procedure. Crown Copyright ª 2017 Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons. All rights reserved.
* Corresponding author. Department of Plastic and Reconstructive Surgery, The Royal Free Hospital, Pond Street, London NW3 2QG, UK. E-mail address: [email protected] (D.P. Butler). http://dx.doi.org/10.1016/j.bjps.2017.02.022 1748-6815/Crown Copyright ª 2017 Published by Elsevier Ltd on behalf of British Association of Plastic, Reconstructive and Aesthetic Surgeons. All rights reserved. Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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Introduction Nerve grafts serve a number of reconstructive purposes ranging from post-traumatic defects to serve as adjuncts in facial reanimation surgery. A common donor nerve is the sural nerve in the lower leg as it provides a long graft length and ease of harvest.1 A further suggested benefit is the minimal donor site morbidity experienced by the patient.2e11 The sural nerve is most commonly formed from the medial sural cutaneous nerve arising from the tibial nerve and a peroneal communicating branch that can arise from the lateral sural cutaneous nerve or the common peroneal nerve directly.12 However, in 27% of cadaveric dissections, the anatomy differed, and five separate variants have been described.12 The function of the sural nerve is purely sensory, supplying a territory over the posterolateral lower limb and lateral aspect of the foot. Given the frequency with which the sural nerve is utilised as a donor nerve, a detailed understanding of the morbidity associated with its harvest is important. The existing literature has demonstrated that sensory loss reduces with time and that morbidity associated with pain, cold intolerance and hypersensitivity are minimal.3e9,13 Many, however, have made this evaluation using nonvalidated patient questionnaires.3,5,7,8 Furthermore, a comparison between outcomes in a paediatric and an adult population has not been made. Finally, an assessment of the outcomes associated with endoscopic sural nerve harvest has not been reported. In this study, we describe the objective sensory, morbidity and functional outcomes associated with endoscopic-assisted sural nerve harvest from a combined paediatric and adult population.
Materials and methods Data were collected prospectively from consecutive patients attending for follow-up between August 2015 and January 2016 who had undergone a sural nerve graft as part of a twostage facial reanimation procedure. For inclusion in the study, patients must have undergone sural nerve harvest using a minimally invasive technique introduced in the department in 2006. Patients were excluded if nerve graft harvest had been <6 months previously, if there had been any other previous surgery to the leg or if they had a systemic disease that could affect the neurological function. Data in five key domains were collected during routine follow-up outpatient clinical appointments, comprising both clinician- and patient-reported outcomes.
Patient and surgical features The first section gathered information on patient demographics, assessment date, surgical site (right or left) and date of nerve harvest.
Sensory loss The loss of sensation was established using a SemmesWeinstein monofilament examination.14 A 5.07/10 g
D.P. Butler et al. Semmes-Weinstein monofilament was chosen, as adult studies have demonstrated that inability to sense touch at this calibre suggests a loss of protective sensation in the foot.15,16 However, no existing studies demonstrate the appropriate Semmes-Weinstein monofilament to evaluate protective sensation in a paediatric population. Lapid et al.9 demonstrated in a control paediatric population that 100% of the volunteers could sense a 3.61 Semmes-Weinstein monofilament or less. Therefore, it was believed that using a 5.07 Semmes-Weinstein in the paediatric patients included in this study was appropriate, given this calibre produces more load on the skin and, in the instance of normal foot sensation, should be felt by the child. After removing the patient’s shoes and socks and ensuring the lower leg was exposed, the patient was asked to respond positively (‘yes’) when they felt the monofilament press against their skin. A demonstration was performed on the patient’s arm prior to commencing the sensory examination of the leg. All patients were instructed to keep their eyes closed throughout the examination. The tip of the monofilament was pressed against the skin until the filament buckled and was then held there for 1 s. An area of sensory loss was mapped out along the lateral aspect of the foot and lower leg. The length and height of this identified area were used to calculate the total area of sensory loss. In children, intermittent testing of the medial aspect of the foot was confirmed so that they were continuing to produce reliable results during the sensory examination.
Pain Patients were asked to use a visual analogue scale of 0 (no pain) to 10 (severe pain) to ascertain pain related to the nerve donor site at the time of review.
Scar The patient’s Fitzpatrick skin type and length of both proximal and distal scars were recorded. The quality of the scarring was assessed using the Patient and Observer Scar Assessment scale.17
Function Lower limb function was assessed using the lower extremity functional scale.18 This score contains 20 patient-reported questions that assess the patient’s ability to perform everyday activities involving the lower limbs. A maximum score of 80 is possible, with a lower score demonstrating a reduced level of function. This score was chosen considering the excellent testeretest reliability and the responsiveness previously demonstrated.19
Surgical technique All nerve graft harvests were performed by the senior surgeon (A.O.G.). A minimally invasive sural nerve graft harvest technique was used,20 and all harvested nerves were used as a cross-facial nerve graft during a first-stage facial
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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Outcomes following sural nerve harvest reanimation procedure. This technique has been standard practice in our department since 2006. Graft harvest was performed with the patient in the supine position under tourniquet control. Access to the sural nerve is made through a vertical incision posterior to the lateral malleolus (Figure 1). The distal nerve is isolated from the surrounding subcutaneous tissue and dissected distally under direct vision as far as possible and then transected. Gentle traction is placed on the distal end of the nerve graft, and proximal dissection is then performed under direct vision. Once proximal dissection can proceed no further, a separate horizontal posterior calf incision is planned at the junction of the proximal and middle third of the calf. The horizontal incision is planned by identifying the point where distal traction on the nerve can be palpated through the skin. After making the skin incision, blunt dissection is used to identify the sural nerve, which is usually deep to the investing fascia of the lower leg and lying between the two bellies of gastrocnemius. Again, proximal and distal dissection of the nerve under is performed direct vision. At this stage, an endoscopic nerve hook is carefully passed along the length of the nerve to identify any points of fixation or additional branches. If gentle traction on the sural nerve through the proximal wound is unable to deliver the nerve graft, then the VascuClear endoscopic vessel harvesting scope (Sorin, USA) is introduced into the distal wound, and any fascial adhesions or nerve branches are divided under direct vision using Endoshears(Covidien, USA). The nerve is then delivered into the proximal wound and transected as far proximal as possible under direct external vision. A graft of 20e30 cm is typically obtained depending on the size of the patient (Figure 2). The proximal stump is buried between the gastrocnemius muscle bellies. Wound closure is performed using interrupted 3-0 Monocryl(Ethicon, USA) deep dermal sutures and a continuous 3-0 Prolene(Ethicon, USA) sub-cuticular suture, which is removed 12e14 days post-operatively.
Statistical analysis Statistical comparison between groups was made using a Student’s t-test, with a p-value of <0.05 considered to be a statistically significant result. Where descriptive data presentation is used, the mean, standard deviation (SD) and
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Figure 2 An intra-operative photograph demonstrating a 20cm section of the nerve harvested from a paediatric patient.
standard error of the mean (SEM) are shown. Statistical data were processed using the 2016 GraphPad Prism Software (GraphPad Software, Inc., California, USA).
Results A total of 40 patients were identified during the study period, incorporating 46 sural nerve grafts harvested for cross facial nerve grafting procedures. Of those, 19 patients were male and 21 were female. The mean age of patients at surgery was 18.1 years with a range of 4e45 years. A total of 28 nerve grafts were harvested from the left leg and 18 from the right leg. The mean time since surgery was 4.3 years (range 0.5e9 years).
Sensory loss
Figure 1 An intra-operative photograph demonstrating the two incisions used to access the sural nerve during endoscopic harvest.
Among the entire study population, the mean area of sensory loss measured using the 5.07 Semmes-Weinstein monofilament was 45.4 cm2 (SD Z 50.4 cm2, SEM Z 7.4 cm2). Five patients had no demonstrable sensory loss. Patients were initially grouped into those aged 18 years (n Z 30) and those aged >18 years (n Z 16). Those aged 18 years had a significantly smaller area of sensory loss (p Z 0.003, Figure 3). A similar trend was found when
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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D.P. Butler et al.
grouping patients into those aged 10 (n Z 23) and >10 years (n Z 23), although this did not reach statistical significance (p Z 0.06, Figure 3). To determine whether the significant difference in the area of sensory loss between those aged 18 and >18 years is due in part to a smaller foot size in the younger of these two patient groups, a separate comparison of those aged 0e8 years (n Z 16) with those aged 9e18 years (n Z 14) was made. No significant difference was found in the area of sensory loss (p Z 0.43, Figure 3). When evaluating the effect of time since surgery on the area of sensory loss, it was shown that those who had undergone surgery 6 months previously (n Z 8) had a significantly larger area of sensory loss than those who had undergone surgery >6 months ago (n Z 38) (p Z 0.0002, Figure 4).
Pain Pain scores were found to be very low with a mean average visual analogue pain score of 0.2 among the study population (SD Z 0.6, SEM Z 0.08). The maximum pain score given from any patient in the study group was 3 out of 10.
Scarring The mean average scar length was 2.8 cm (SD Z 0.9, SEM Z 0.1) for the proximal wound and 4.1 cm (SD Z 1.0, SEM Z 0.2) for the distal wound. The mean average patient-rated scar score was 9.1/60 (SD Z 6.7, SEM Z 1.0) and 9.8/50 (SD Z 5.8, SEM Z 0.9) for the observer-rated scar score. A score of six and five were considered to represent normal skin for the patient and observer-rated scar score, respectively.
Function According to the lower extremity functional scale, minimal effect on function was found with a group mean average score of 78.74 out of a maximum of 80 (SD Z 4.13, 80
SEM Z 0.61). No significant differences in function were observed when comparing patients according to age at the time of surgery and time since surgery (Figure 5).
Discussion This present study has shown that endoscopic-assisted sural nerve grafting is associated with minimal pain and good scarring outcomes. In addition, patients of all ages in our study had excellent post-operative function, according to the lower extremity functional scale. Our results also add to the body of evidence that the area of sensory loss following sural nerve graft harvest reduces with time. This is in keeping with other studies published on this subject (Table 1). Aszmann et al. suggested that this was as a result of sprouting from adjacent nerves.13 They also found that sensory recovery began as early as 3 weeks post-operatively and that upon performing an anaesthetic block of the adjacent named sensory nerves, the area of sensory loss returned to that seen postoperatively. Given that patients who underwent surgery before the age of 18 showed significantly reduced areas of sensory loss, there must be additional factors that contribute to the improved sensation demonstrated during prolonged follow-up. It may be that cortical re-mapping and cerebral plasticity in the paediatric brain account for this finding.4,21 Despite the occasionally large areas of sensory loss demonstrated in this study, the associated functional limitations are minimal. This is in keeping with studies that have demonstrated that loss of sural nerve function has little effect on postural stability and joint proprioception during activities that would be classified as activities of normal daily living.22,23 Mazzella and McMillan, however, demonstrated a considerable reduction in postural stability when standing on the non-dominant leg following a sural nerve block,22 and others have found a discernible change in patient gait following graft harvest.24 This could, therefore, have implications for athletes and those with pre-existing impairment of the contralateral leg. Currently
74.8
AREA OF SENSORY LOSS (CM²)
70 59
60 50 40 30
29.6
31.7
34.7 23.9
20 10 0 ≤18 years old >18 years old ≤10 years old >10 years old ≤8 years old 9-18 years old AGE GROUP
Figure 3
A graph to demonstrate the area of sensory loss according to grouped age.
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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Outcomes following sural nerve harvest
5
120 101.6
AREA OF SENSORY LOSS (CM²)
100 80 60 40
33.6
20 0 6 months ago
>6 months ago TIME SINCE SURGERY
Figure 4
A graph to demonstrate the effect of time since surgery on the area of measurable sensory loss.
LOWER EXTREMITY FUNCTIONAL SCALE SCORE (MAX=80)
90 80
79.4
77.4
79.3
78.3
≤2 years since surgery
>2 years since surgery
70 60 50 40 30 20 10 0 ≤18 years old
Figure 5
>18 years old
A graph to demonstrate the effect of age at surgery and time since surgery on post-operative function.
available lower limb functional scores, such as that used in this study, are unlikely to be sensitive enough to detect such a limitation. As such, careful consultation should be had with each individual patient to identify the future demands required of each potential donor limb. Comparing the area of sensory loss associated with different sural nerve harvest techniques is not possible because of the different measurement methods used. It is unlikely, however, that altering the harvest technique will alter the associated sensory loss as all techniques have the ultimate aim of removing the sural nerve. The effect of incision length and direction associated with different harvesting techniques on sensory loss is unclear and cannot be established from this study. In addition to the minimal functional limitation occurring after sural nerve harvest, our patient population showed very low post-operative pain scores. Similarly low
levels have been observed in previous studies, which have also noted that cold intolerance and hypersensitivity are uncommon after the removal of the sural nerve.2e6,8 The combination of low post-operative pain and minimal functional deficit supports the ongoing use of the sural nerve as a common source for a nerve graft. Harvesting the nerve through an endoscopic-assisted approach serves to minimise the scars associated with harvest, and our study has shown excellent patient- and observer-rated scar scores. Other minimally invasive techniques exist for harvesting the sural nerve, such as using a tendon or nerve stripper passed from the distal to the proximal wound.8,25 We believe that the benefit of directly visualising the dissection of the nerve in areas of adhesion under endoscopic vision aids to minimise the risk of iatrogenic injury to the nerve,25,26 which in the context of a cross-facial nerve graft procedure would necessitate harvest of the
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
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Overview of sensory changes reported in previous studies on sural nerve graft harvest.
Study
Population
Indication for graft
Length of graft
Harvest technique
Data collection
Donor sensory loss?
Sensory recovery with time?
This study
Mixed (n Z 46)
Cross facial nerve graft
20e30 cm
Endoscopic
Yes
Yes
Aszmann 199613
Adults (n Z 3)
Not specified
Not specified
Not specified
Yes
Yes
Not specified Peripheral nerve defect repair
Not specified “Whole length”
Sensory evaluation in clinic e SemmesWeinstein Sensory evaluation in clinic e Pressure Specifying Sensory Device Telephone questionnaire Postal questionnaire
Not specified 54% e multiple stab incisions 15% e single longitudinal incision 31% e not specified Not specified Postal questionnaire
Yes Yes
Yes Yes
Yes
Yes
18e20 cm
Minimal access using tendon stripper
Not reported Not reported
Not specified
Not specified
Ehretsman 19994 Mixed (n Z 16) Hallgren 20132 Mixed (n Z 41)
Adults (n Z 29)
Lapid 20079
Peripheral nerve defect repair Adults (n Z 12) Radical prostatectomy nerve defect reconstruction Children (n Z 14) Brachial plexus surgery
Martins 20127
Mixed (n Z 40)
Miloro 20053 Ng 20066
Kim 20018
Not specified
Varied according to requirement
Single longitudinal incision
Adults (n Z 26)
Brachial plexus surgery and peripheral nerve defects Trigeminal nerve repair
2.5e4 cm
Adults (n Z 20)
Not specified
Not specified
Single longitudinal incision Single longitudinal incision
Patient reported outcome in clinic e McGill pain questionnaire Sensory evaluation in clinic e SemmesWeinstein Sensory evaluation in clinic e light brush sensation Telephone questionnaire Sensory evaluation in clinic e pin prick
MODEL
Ijpma 20065
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Yes
Not tested
Yes
Yes
Yes
Yes
Yes
Yes
D.P. Butler et al.
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022
Table 1
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Outcomes following sural nerve harvest contralateral sural nerve and result in additional scarring. Our technique is similar to that described by Capek in 1996.20 Where required, the length of the nerve harvested can be extended by the addition of a third transverse incision in the popliteal fossa.27 Other authors have modified the technique to simply perform a stab incision to divide the nerve proximally28 or to harvest the nerve through one distal incision at the lateral malleolus alone.29,30 In our experience, the time to harvest the sural nerve using the endoscopic-assisted technique is equivalent to the multi-incision open approach. A standard endoscopy stack can be used in combination with the single-use Vascuclear and Endoshear equipment. The excellent scar outcomes shown in this study support the use of a minimally invasive approach despite the additional cost of the disposable endoscopic equipment. Our study is the first to report the objective sensory and functional outcomes associated with endoscopic-assisted sural nerve graft harvest. Furthermore, we have demonstrated a significantly reduced post-harvest sensory deficit among a paediatric population compared to that seen in adults. Despite the sensory loss resulting from sural nerve graft harvest, there is minimal loss of function. As such, the sural nerve continues to be an excellent donor for a nerve graft procedure.
Conflicts of interest statement No conflicts of interest to declare.
Financial disclosure statement No funding given towards this study.
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7 9. Lapid O, Ho ES, Goia C, Clarke HM. Evaluation of the sensory deficit after sural nerve harvesting in pediatric patients. Plast Reconstr Surg 2007 Feb;119(2):670e4. 10. Kumar S, Jacob J. Variability in the extent of sensory deficit after sural nerve biopsy. Neurol India 2004 Dec;52(4):436e8. 11. Poburski R, Malin JP, Stark E. Sequelae of sural nerve biopsies. Clin Neurol Neurosurg 1985;87(3):193e8. 12. Riedl O, Frey M. Anatomy of the sural nerve: cadaver study and literature review. Plast Reconstr Surg 2013 Apr;131(4): 802e10. 13. Aszmann OC, Muse V, Dellon AL. Evidence in support of collateral sprouting after sensory nerve resection. Ann Plast Surg 1996;37:520e5. 14. Weinstein S. Fifty years of somatosensory research: from the semmes-Weinstein monofilaments to the Weinstein enhanced sensory test. J Hand Ther 1993;6:11e22. 15. Feng Y, Schlosser FJ, Sumpio BE. The Semmes Weinstein monofilament examination as a screening tool for diabetic peripheral neuropathy. J Vasc Surg 2009;50(3):675e82. 16. Jeng C, Michelson J, Mizel M. Sensory thresholds of normal human feet. Foot Ankle Int 2000;21:501e4. 17. Draaijers LJ, Tempelman FR, Botman YA, et al. The patient and observer scar assessment scale: a reliable and feasible tool for scar evaluation. Plast Reconstr Surg 2004 Jun;113(7):1960e5. 18. Binkley JM, Stratford PW, Lott SA, Riddle DL. The lower extremity functional scale (LEFS): scale development, measurement properties, and clinical application. North American orthopaedic rehabilitation research network. Phys Ther 1999 Apr;79(4):371e83. 19. Mehta SP, Fulton A, Quach C, Thistle M, Toledo C, Evans NA. Measurement properties of the lower extremity functional scale: a systematic review. J Orthop Sports Phys Ther 2016 Jan 26:1e39 [Epub ahead of print]. 20. Capek L, Clarke HM, Zuker RM. Endoscopic sural nerve harvest in the pediatric patient. Plast Reconstr Surg 1996 Oct;98(5): 884e8. 21. Johnston MV. Brain plasticity in paediatric neurology. Eur J Paediatr Neurol 2003;7(3):105e13. 22. Mazzella NL, McMillan AM. Contribution of the sural nerve to postural stability and cutaneous sensation of the lower limb. Foot Ankle Int 2015 Apr;36(4):450e6. 23. Rein S, Fabian T, Krishnan K, et al. Evaluation of the proprioceptive influence of the cutaneous afferents to the ankle in patients after sural nerve harvesting. Neurosurgery 2009 Mar; 64(3):519e25. 24. Yavuzer R, Yavuzer G, Ergin S, Latifoglu O. Gait analysis: a new perspective on sural nerve graft donor site morbidity assessment. Ann Plast Surg 2002;48(4):449e50. 25. Hassanpour E, Yavari M, Karbalaeikhani A, Saremi H. Nerve stripper-assisted sural nerve harvest. J Neurol Surg A Cent Eur Neurosurg 2014;75(2):161e4. 26. Jaroszynski G, Johnston GH. Harvesting of the sural nerve with a tendon stripper. Microsurgery 1996;17(4):217e20. 27. Capek L, Clarke HM. Endoscopically assisted sural nerve harvest in infants. Semin Plast Surg 2008;22(1):25e8. 28. Spinks TJ, Adelson PD. Pediatric sural nerve harvest: a fully endoscopic technique. Neurosurgery 2009 May;64:360e3. 29. Park SB, Cheshier S, Michaels D, Murovic JA, Kim DH. Endoscopic harvesting of the sural nerve graft: technical note. Neurosurgery 2006;58(Suppl. 1). ONS-E180. 30. Hadlock TA, Cheney ML. Single-incision endoscopic sural nerve harvest for cross face nerve grafting. J Reconstr Microsurg 2008;24(7):519e23.
Please cite this article in press as: Butler DP, et al., Objective sensory and functional outcomes at the donor site following endoscopicassisted sural nerve harvest, Journal of Plastic, Reconstructive & Aesthetic Surgery (2017), http://dx.doi.org/10.1016/j.bjps.2017.02.022