Sequelae of sural nerve biopsies

Diagnostic yield of nerve biopsy in the evaluation of peripheral neuropathies

BACKGROUND

With progress made in neurogenetics and neuroinflammation, the indications and value of nerve biopsies in the diagnostic evaluation of peripheral neuropathies are less clear. In this study, we aimed to evaluate the diagnostic yield of nerve biopsies in patients with peripheral neuropathies.

METHODS

We performed a retrospective review of nerve biopsy reports from April 1998 to June 2021 of patients with peripheral neuropathies presenting to the Department of Pathology, University of Malaya Medical Centre, Kuala Lumpur, Malaysia. The diagnostic value of the biopsies was determined based on the criteria by Midroni and Bilbao as follows: contributive (essential and helpful), non-contributive and inadequate.

RESULTS

A total of 107 nerve biopsies were analysed. Sixty-four (60 %) were males and the mean age was 52 years, ranging from 13 to 86 years. Ninety-four (88 %) were sural nerve biopsies; and only one patient (1 %) each had superficial peroneal and superficial radial nerve biopsy. The indications for the procedure were vasculitis (34 %), peripheral neuropathy of unknown aetiology (34 %), amyloidosis (14 %) and chronic inflammatory demyelinating polyneuropathy (10 %). In 68 (63 %) biopsies, the diagnostic value was contributive. Of these, 28 (26 %) were essential and 40 (37 %) were helpful. In contrast, 35 (33 %) biopsies were non-contributive and 4 (4 %) were inadequate. In 66 % (71/107) of cases, the nerve biopsy did not reveal a definite pathological diagnosis. However, in the remainder, a diagnosis of vasculitis (18 %, 19/107), followed by amyloidosis (10 %, 11/107) could be determined. For 32/71 biopsies with undetermined pathological diagnosis, neuropathy remained cryptogenic in 22 % (7/32) upon follow up.

CONCLUSIONS

With the exception of vasculitis and amyloidosis, there is limited value in performing nerve biopsies in the evaluation of patients with peripheral neuropathy. However, this should be interpreted with caution as the number of patients with a clinical diagnosis of vasculitis and amyloidosis were relatively larger than patients with other diagnosis. Refinement and careful selection of cases are required to increase the diagnostic yield of nerve biopsy.

Diagnostic Value of Sural Nerve Biopsy: Retrospective Analysis of Clinical Cases From 1981 to 2017

Nerve biopsy represents the conclusive step in the diagnostic work-up of peripheral neuropathies, and its diagnostic yield is still debated. The aim of this study is to consider the impact of nerve biopsy on reaching a useful diagnosis in different peripheral neuropathies and its changing over time. We retrospectively analyzed 1,179 sural nerve biopsies performed in the period 1981–2017 at Neurological Clinic of Policlinico San Martino (Genoa). We relied on medical records and collected both clinical and pathological data in a database. Biopsy provided univocal diagnoses in 53% of cases (with an increase over time), multiple diagnostic options in 14%, while diagnosis was undetermined in 33% (undetermined reports decreased during the years). In 57% of patients, the pre-biopsy suspicion was confirmed, while in 43% sural biopsy modified the clinical diagnosis. The highest yield was in axonal neuropathies (29% undetermined reports vs. 40% in demyelinating and 48% in mixed neuropathies). In 68% of patients with vasculitic neuropathy, this etiology was already suspected, whereas in 32% nerve biopsy modified the clinical diagnosis. During the years, the number of annually performed biopsies decreased significantly (p = 0.007), with an increase in the mean age of patients (p < 0.0001). The percentage of hereditary neuropathies had a significant decrease (p = 0.016), while the rate of vasculitic and chronic inflammatory neuropathies increased (p < 0.0001). This is the largest Italian study addressing the yield of sural nerve biopsy. During the years, we observed a progressive refinement of the indication of this procedure, which confirms its utility for interstitial neuropathies, particularly if non-systemic vasculitic neuropathy is suspected.

Clinical and biometrical 12-month follow-up in patients after reconstruction of the sural nerve biopsy defect by the collagen-based nerve guide Neuromaix

Many new strategies for the reconstruction of peripheral nerve injuries have been explored for their effectiveness in supporting nerve regeneration. However only a few of these materials were actually clinically evaluated and approved for human use. This open, mono-center, non-randomized clinical study summarizes the 12-month follow-up of patients receiving reconstruction of the sural nerve biopsy defect by the collagen-based nerve guide Neuromaix. Neuromaix was implanted as a micro-structured, two-component scaffold bridging 20–40 mm nerve defects after sural nerve biopsy in twenty patients (eighteen evaluated, two lost in follow-up). Safety of the material was evaluated by clinical examination of wound healing. Performance was assessed by sensory testing of modalities, pain assessment, and palpation for the Hoffmann–Tinel’s sign as well as demarcating the asensitive area at each follow-up visit. Every patient demonstrated uneventful wound healing during the complete 12-month time course of the study. Two patients reported complete return of sensation, whereas eleven out of eighteen patients reported a positive Hoffmann–Tinel’s sign at the lower leg with simultaneous reduction of the asensitive area by 12 months. Our data show that Neuromaix can be implanted safely in humans to bridge sural nerve gaps. No procedure-related, adverse events, or severe adverse events were reported. These first clinical data on Neuromaix provide promising perspectives for the bridging of larger nerve gaps in combined nerves, which should be investigated more through extensive, multi-center clinical trials in the near future.

The proximal medial sural nerve biopsy model: a standardised and reproducible baseline clinical model for the translational evaluation of bioengineered nerve guides

Autologous nerve transplantation (ANT) is the clinical gold standard for the reconstruction of peripheral nerve defects. A large number of bioengineered nerve guides have been tested under laboratory conditions as an alternative to the ANT. The step from experimental studies to the implementation of the device in the clinical setting is often substantial and the outcome is unpredictable. This is mainly linked to the heterogeneity of clinical peripheral nerve injuries, which is very different from standardized animal studies. In search of a reproducible human model for the implantation of bioengineered nerve guides, we propose the reconstruction of sural nerve defects after routine nerve biopsy as a first or baseline study. Our concept uses the medial sural nerve of patients undergoing diagnostic nerve biopsy (≥ 2 cm). The biopsy-induced nerve gap was immediately reconstructed by implantation of the novel microstructured nerve guide, Neuromaix, as part of an ongoing first-in-human study. Here we present (i) a detailed list of inclusion and exclusion criteria, (ii) a detailed description of the surgical procedure, and (iii) a follow-up concept with multimodal sensory evaluation techniques. The proximal medial sural nerve biopsy model can serve as a preliminary nature of the injuries or baseline nerve lesion model. In a subsequent step, newly developed nerve guides could be tested in more unpredictable and challenging clinical peripheral nerve lesions (e.g., following trauma) which have reduced comparability due to the different nature of the injuries (e.g., site of injury and length of nerve gap).

Morbidity following sural nerve harvesting: a prospective study

OBJECTIVE

To evaluate donor site morbidity following sural nerve harvesting, with special attention to the recovery of sensory loss.

METHODS

We prospectively followed 38 subjects who underwent sural nerve harvest, including two with bilateral nerve excision. Symptoms related to sural nerve excision were evaluated and demarcation of the area with reduced touch sensation was quantified. Assessments were performed periodically up to 1 year after surgery and the results of different sensory evaluations were compared.

RESULTS

A significant reduction of sensory deficit was identified between consecutive evaluations (p<0.05). Decreases of 26.85%, 20.69% and 24.29% were observed 3, 6 and 12 months after surgery, respectively. Shock-like pain (7.5%), stabbing pain (7.5%), and numbness (5%) were the most frequently reported symptoms. All symptoms were brief and resolved spontaneously 3-6 months after surgery.

CONCLUSION

Sural nerve harvest can be performed with acceptable morbidity. When present, symptoms resolve between the third and sixth month after surgery and a significant reduction of sensory loss in the area innervated by the sural nerve was observed during the first year of follow-up.

The use of autogenous veins for microsurgical repair of the sural nerve after nerve biopsy

OBJECTIVES

This study evaluates the results of an alternative technique developed to minimize the risk of complications associated with sural nerve biopsy for histopathological analysis.

METHODS

Twelve subjects underwent sural nerve biopsy and the defect created in the nerve was bridged by a 50-mm-length segment of the saphenous vein; the control group enrolled 23 patients in whom the entire length of the nerve was harvested to be used as autograft for reconstruction of nerves in the upper limb. Sensory reinnervation was quantified by use of the monofilament test and the static 2-point discrimination test, after a follow-up period of 18 months.

RESULTS

The mean time for recovery of protective sensation was 8.7 months in patients submitted to nerve repair, and 10.3 months in the control group (P > .05). The monofilament test and static 2-point discrimination testing demonstrated a mean value of 3.22 and 8 mm (S3), respectively, in the group who underwent sural nerve repair; and 4.17 and 13 mm (S2), respectively, for the control group (P <.05).

CONCLUSION

The use of vein as conduits for the repair of the sural nerve did not shorten the time for sensory recovery at the autonomous zone of the nerve; however, the quality of the reinnervation was considered better than the control group. This study suggests that empty veins could be used as conduits to bridge gaps with a length up to 50 mm in cases of injuries of the sural nerve and, possibly, for injuries of other pure sensory nerves as well.

Sequelae following sural nerve biopsy in type 1 diabetic subjects

OBJECTIVES

To detect post-operative sequelae of sural nerve biopsy.

MATERIALS AND METHODS

A questionnaire mailed to type 1 diabetic patients (n = 24; male/female 23/1; reply n = 23) 2 years after biopsy.

RESULTS

Type 1 diabetic patients (age 56 [11]; median [interquartile range]) had a long duration of diabetes (DM; 20 [19] years) and all had neuropathy. Three out of 24 patients developed infection (two superficial and one deep) and one had a post-operative bleeding. Less frequent pain among the patients were reported from one centre. About one-third or more of the patients still complained of pain, mostly mild, in the biopsy area and paraesthesia in the foot 2 years after surgery. More than two-thirds of the patients were reluctant for further biopsy; a crucial information in drug trial planning.

CONCLUSIONS

Sequelae of a sural nerve biopsy occur in type 1 DM. The risk for wound infections should be considered.

Complications following sural and peroneal nerve biopsies

Nerve biopsy is used as part of the investigation of patients with peripheral neuropathy and is particularly useful in confirming the diagnosis of peripheral nerve vasculitis. Previous studies have suggested that sampling the peroneal nerve, in combination with peroneus brevis, is more sensitive than the sural nerve for this diagnosis but there are no published data on the complication rate of peroneal nerve biopsies. We have assessed the complications in 50 patients undergoing nerve biopsy, and have shown that although biopsy of the peroneal nerve may result in a larger area of sensory loss in some patients, other complications are not increased when compared with sural nerve biopsy.

Evaluation and treatment of hip dysplasia in Charcot-Marie-Tooth disease

The hip dysplasia seen in Charcot-Marie-Tooth disease is neuromuscular in nature. It usually presents in the second or third decade of life and is initially asymptomatic but may later present with pain and gait abnormalities. Treatment should be aimed at addressing the acetabular and femoral components of the dysplasia. Early recognition is essential to avoid serious morbidity associated with the condition.

Diagnostic and therapeutic value due to suspected diagnosis, long-term complications, and indication for sural nerve biopsy

In order to elicit the usefulness of sural nerve biopsy we retrospectively evaluated the courses of disease of every patient, who underwent this procedure in our department between January 1995 and March 2000. Sixty seven patients with the suspected diagnosis of peripheral neuropathy could be included. From these chart reviews and patient questionings were done. Inflammatory-demyelinating neuropathies were suspected in 14 patients (20.9%), specific histological findings confirmed diagnosis in 50% of these patients and resulted in therapy. In cases of polyneuropathy of unknown etiology (46 patients, 68.6%) diagnosis was made in 11 patients (23.9%), and lead to therapy in 9 patients (19.6%), merely. In all, diagnostic consequences arouse in 32.8%, therapeutic consequences in 26.9%. The follow-up of 47 patients (mean 24.4 months) found chronic pain in the distribution of the sural nerve in 14 patients (29.8%), dysesthesia in 22 patients (46.8%), and persistent sensory loss in 34 patients (72.3%). Only 24 patients (51.1%) would submit to biopsy again. Because of high complication rates and poor results we conclude that sural nerve biopsy should be done only in carefully selected cases after thorough clinical work-up, and should be limited to cases of suspected inflammatory neuropathies, collagenoses and immunologic neuropathies, and hereditary neuropathies.

Regeneration of Peripheral Nerve Gaps with a Polyglycolic Acid-Collagen Tube

OBJECTIVE:

The aim of this study was to report by means of objective methods on the effectiveness of a nerve reconstruction procedure using a bioresorbable tube in two patients. Our previous successes in regenerating canine peripheral nerves across long distances (80-mm gaps) using a bioabsorbable tube have led us to investigate the value of such a tube for the treatment of human patients with chronic nerve injuries.

METHODS:

The device was made from a cylindrically woven polyglycolic acid tube filled with a collagen sponge. It was designed to be resorbed after nerve regeneration. Peripheral sensory nerve defects in two patients with neuroma and pain were reconstructed using this tube. Patient 1 (a 62-year-old man) had a 20-mm defect of the proper digital nerve, and Patient 2 (a 56-year-old woman) had a 65-mm defect of the superficial peroneal nerve.

RESULTS:

After surgery, both patients recovered from the unpleasant sensations and intolerable pain. In Patient 1, functional recovery was objectively identified at 2 months, and conduction velocity of the nerve recovered to 49.1 m/s. In Patient 2, conduction velocity of the nerve was determined to be 16.9 m/s at 5 months. Current perception threshold testing indicated that sensory nerve function had been recovered by 65 days after surgery.

CONCLUSION:

This work represents the first precise clinical evaluation, performed under objective evaluation criteria, of sensory recovery achieved using a nerve tube, suggesting that the use of a polyglycolic acid-collagen tube has the potential to become a viable alternative to conventional autografting for the repair of peripheral nerve defects.

Microsurgical Repair of the Sural Nerve after Nerve Biopsy to Avoid Associated Sensory Morbidity: A Preliminary Report

OBJECTIVE

The purpose of this article is to report our preliminary results regarding microsurgical repair of the sural nerve after nerve biopsy, in an attempt to reduce the well-described sensory morbidity and neuroma formation.

METHODS

Three patients with a suspected diagnosis of peripheral neuropathy underwent sural nerve biopsies to establish definitive diagnoses. A 10-mm segment of the sural nerve was resected with local anesthesia. After harvesting of the specimen, the proximal and distal nerve stumps were carefully mobilized and united with epineural suture techniques, under a surgical microscope. Sensory evaluations (assessing the presence of hypesthesia/dysesthesia or pain) of the lateral aspect of the foot, in regions designated Areas 1, 2, and 3, were performed before and 6 and 12 months after the biopsies. A visual analog scale was used for pain estimation.

RESULTS

The biopsy material was sufficient for histopathological examinations in all cases, leading to conclusive diagnoses (vasculitis in two cases and amyloidosis in one case). The early post-biopsy hypesthesia, which was present for 4 to 8 weeks, improved to preoperative levels as early as 6 months after the nerve repair. Sensory evaluations performed at 6- and 12-month follow-up times demonstrated that none of the patients complained of pain at the biopsy site or distally in the area innervated by the sural nerve. Ultrasonography performed at the 12-month follow-up examination revealed normal sural nerve morphological features, with no neuroma formation, comparable to findings for the contralateral site.

CONCLUSION

Microsurgical repair of the sural nerve after biopsy can eliminate or reduce sensory disturbances such as paraesthesia, hypesthesia, and dysesthesia distal to the biopsy site, in the distribution of the sensory innervation of the sural nerve, and can prevent painful neuroma formation. To our knowledge, this article is the first in the literature to report on microsurgical repair of the sural nerve after nerve biopsy. Decreased side effects suggest that this technique can become a standard procedure after sural nerve biopsy, which is commonly required to establish the diagnosis of various diseases, such as peripheral nerve pathological conditions, vasculitis, and amyloidosis. More cases should be analyzed, however, to explore the usefulness of the technique and the reliability of sural nerve biopsy samples in attempts to obtain conclusive diagnoses.

Neuroma sintomático do nervo sural uma complicação rara após a retirada do nervo: relato de caso

A retirada do nervo sural para utilização como enxerto autólogo em cirurgias de nervos em geral produz sintomas de repercussão clínica pouco intensa e de duração fugaz. Raramente este procedimento leva a formação de neuroma sintomático no coto proximal. Os sintomas deste tipo de complicação frequentemente cessam após o tratamento clínico e o tratamento cirúrgico é reservado para os raros casos nos quais houve falha terapêutica. Neste estudo, apresentamos o caso de um paciente que foi submetido a tratamento cirúrgico desta patologia, com a utilização de uma variação da anastomose centro-central, descrita para o tratamento de neuromas de cotos de amputação. A utilização deste tratamento resultou na remissão da sintomatologia dolorosa. São discutidas as diversas opções de tratamento cirúrgico para essa rara entidade.

A randomized prospective study of polyglycolic acid conduits for digital nerve reconstruction in humans

This article reports the first randomized prospective multicenter evaluation of a bioabsorbable conduit for nerve repair. The study enrolled 98 subjects with 136 nerve transections in the hand and prospectively randomized the repair to two groups: standard repair, either end-to-end or with a nerve graft, or repair using a polyglycolic acid conduit. Two-point discrimination was measured by a blinded observer at 3, 6, 9, and 12 months after repair. There were 56 nerves repaired in the control group and 46 nerves repaired with a conduit available for follow-up. Three patients had a partial conduit extrusion as a result of loss of the initially crushed skin flap. The overall results showed no significant difference between the two groups as a whole. In the control group, excellent results were obtained in 43 percent of repairs, good results in 43 percent, and poor results in 14 percent. In those nerves repaired with a conduit, excellent results were obtained in 44 percent, good results in 30 percent, and poor results in 26 percent (p = 0.46). When the sensory recovery was examined with regard to length of nerve gap, however, nerves with gaps of 4 mm or less had better sensation when repaired with a conduit; the mean moving two-point discrimination was 3.7 +/- 1.4 mm for polyglycolic acid tube repair and 6.1 +/- 3.3 mm for end-to-end repairs (p = 0.03). All injured nerves with deficits of 8 mm or greater were reconstructed with either a nerve graft or a conduit. This subgroup also demonstrated a significant difference in favor of the polyglycolic acid tube. The mean moving two-point discrimination for the conduit was 6.8 +/- 3.8 mm, with excellent results obtained in 7 of 17 nerves, whereas the mean moving two-point discrimination for the graft repair was 12.9 +/- 2.4 mm, with excellent results obtained in none of the eight nerves (p < 0.001 and p = 0.06, respectively). This investigation demonstrates improved sensation when a conduit repair is used for nerve gaps of 4 mm or less, compared with end-to-end repair of digital nerves. Polyglycolic acid conduit repair also produces results superior to those of a nerve graft for larger nerve gaps and eliminates the donor-site morbidity associated with nerve-graft harvesting.

Prospective study of the usefulness of sural nerve biopsy

OBJECTIVE

This study aimed to determine the usefulness of sural nerve biopsy in neurological practice.

METHODS

The first prospective study of sural nerve biopsy in 50 consecutive patients was undertaken. The investigating neurologist declared the prebiopsy diagnosis and management plan and after 3 months an independent neurologist evaluated the contribution of the biopsy to diagnosis and management. An independent audit officer sought information from the patient about the adverse effects and value of the biopsy after 6 weeks and 6 months.

RESULTS

In seven cases the nerve biopsy changed the diagnosis, in 35 cases the biopsy confirmed the suspected diagnosis, and in eight cases the biopsy was non-contributory. The biopsy either changed or was helpful in guiding patient management in 60%, especially those with demyelinating neuropathy and multiple mononeuropathy. Seven patients reported having had infection and 10 reported increased pain at the biopsy site 6 months later.

CONCLUSION

In a consecutive series of 50 cases, sural nerve biopsy altered the diagnosis in 14%, affected management in 60%, and caused persistent increased pain at the biopsy site in 33%.

Clinical and neuropathological parameters affecting the diagnostic yield of nerve biopsy

The value of nerve biopsy in the investigation of peripheral neuropathies is an important and controversial issue, partially obscured by the large variations in the diagnostic yield routinely reported for this procedure. The aim of this study was to evaluate the clinical and neuropathological parameters affecting the yield of nerve biopsy. We compared the experience of two independent neuropathology laboratories with different patient recruitment and neuropathological methods over 11 years (01/1987-12/1997). Clinicopathological correlations were studied retrospectively in 355 patients. Using the same criteria of evaluation, contributive biopsies accounted for 35.5% in one laboratory, and 47.3% in the other. Clinical parameters affecting the yield of nerve biopsy were: (a) the presumptive diagnosis at time of referral for biopsy; (b) the distribution of symptoms; and (c) the interval between disease onset and biopsy. Greater yield was associated with clinically suspected vasculitis, inflammatory demyelinating neuropathy or hereditary sensorimotor neuropathies. Contributive findings were more often reported with multifocal or asymmetrical presentations, and onset-to-biopsy interval of less than 6 months. The contribution of nerve biopsy varied according to neuropathological techniques: (a) serial sections on frozen. paraffin-embedded and resin-embedded material improved sensitivity for interstitial pathology: (b) combined muscle biopsy increased sensitivity in the detection of vasculitis; and (c) teasing of nerve fibers added critical information to other classical techniques in only 4/102 cases.

Complications of sural nerve biopsy in diabetic versus non-diabetic patients

We compare complications from 66 sural nerve biopsies in 41 patients with diabetic peripheral neuropathy to 40 patients with neuropathy from other causes, using a retrospective telephone survey. Diabetic patients were followed for a mean of 6.8 years and non-diabetics for 5.6 years. Mild long-term pain was described by 18.9% of patients overall with no difference between groups. Mild persistent sensory symptoms, insufficient to interfere with daily activity or warrant medical therapy, were reported by 63.6% of diabetic and 27.5% of non-diabetic patients (p < 0.006). Wound infection and severe pain were uncommon in both groups and no different in diabetics. Significant complications of sural nerve biopsy occurred no more frequently in diabetic than in non-diabetic patients. While sural nerve biopsy plays no role in the routine evaluation of diabetic peripheral neuropathy, it may be performed without increased risk when indicated in these patients to exclude other causes of neuropathy and in the context of research trials.

Discomfort after fascicular sural nerve biopsy

Sural nerve biopsy may, in selected cases, give valuable information in the investigation of patients with polyneuropathy. The prevalence and severity of patient discomfort after fascicular nerve biopsy was investigated in 67 patients by a mailed questionnaire. A lasting (greater than 6 months) significant discomfort was found in 6 patients (11%), in 3 of these the symptoms were graded as severe. Thus, sural nerve biopsy should be limited to cases in which important information may be expected and the patients should be carefully informed of the risks of long-lasting discomfort.