Clinical utilization and complications of sural nerve biopsy

Nervo alógeno conservado em glicerol: estudo experimental em ratos

A utilização de aloenxerto de nervo conservado em glicerol é uma alternativa a auto-enxertia em casos de lesões de nervos periféricos com perda de substância que diminui a morbidade cirúrgica e provem material suficiente para a reparação neural. O objetivo deste trabalho foi comparar o grau de reparação nervosa, utilizando análises histológica e funcional, através da interposição de enxerto autógeno (grupo A), de tubo de veia conservada em glicerol (grupo B) e de interposição de nervo alógeno conservado em glicerol (grupo C) em defeitos de 5 mm no nervo fibular de ratos Wistar. A análise histológica foi feita após o sacrifício dos animais( 6 semanas) , usando o corante azul de toluidina a 1%. No grupo A (auto-enxerto) verificou-se reação tecidual perineural e escape de fibras axonais mielinizadas para fora dos limites do epineuro que foi maior se comparada ao verificado no Grupo B (Veia autógena + glicerol) e Grupo C (aloenxerto de nervo).A avaliação funcional foi feita através da análise dos padrões das pegadas das patas posteriores dos ratos ("Walking Track Analysis"), nos períodos: pré-operatório, pós-operatório imediato, na terceira e sexta semanas. Na recuperação funcional, não houve diferença estatisticamente significativa entre os três grupos em nenhum dos períodos avaliados.

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.

Medial sural cutaneous nerve biopsy

This paper describes indications, preoperative preparation, operative technique, and postoperative care for an adaptation of a commonly performed, outpatient neurology procedure, the sural nerve biopsy. We performed a chart review on 12 patients, with follow-ups ranging from 6 to 26 months, treated by the PI (J.F.T.) over 3 years, and only 1 noted complication (delayed wound healing in a steroid-dependent person). All procedures were performed in an operating room setting under local anesthetic with standby intravenous sedation. We provide a stepwise procedure description of this technique that can be performed with very low morbidity in an outpatient, minor procedure setting.

Surgical relief of causalgia with an artificial nerve guide tube: Successful surgical treatment of causalgia (Complex Regional Pain Syndrome Type II) by in situ tissue engineering with a polyglycolic acid-collagen tube

Two patients with causalgia associated with allodynia and finger contracture were treated surgically with a bioresorbable nerve guide tube made from polygycolic acid and collagen: the injured segment of the digital nerve was resected and the resulting gap (25 and 36mm) was bridged with the tube. In both cases, a neuroma was found on the injured nerve and many sprouting branches were. After reconstruction, the causalgia and allodynia disappeared and movement of the fingers recovered during the following 6 months. Functional recovery was objectively identified for 1 year and 9 months. Both patients regained full use of their finger and were free of discomfort for up to 24 and 18 months, respectively. Since the first description of causalgia in 1864, there has been no definitive treatment for this intractable burning pain. Our experience shows that at least some types of causalgia can be resolved successfully by surgery.

Nerve conduits

The evolution of peripheral nerve repair is reviewed with respect to the development of the nerve conduit. The rationale and available scientific evidence to support the use of nerve conduits is presented. Therapy evaluation and treatment protocols for patients with peripheral nerve repairs with nerve conduits are detailed. The authors present clinical experience to date with 73 cases of peripheral nerves repaired with the NeuraGenR collagen nerve conduit.

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.

Drug therapy for chronic idiopathic axonal polyneuropathy

BACKGROUND

Chronic idiopathic axonal polyneuropathy is an insidiously progressive sensory or sensorimotor polyneuropathy that affects elderly people. Although severe disability or handicap does not occur, it reduces quality of life.

OBJECTIVES

To assess whether drug therapy for chronic idiopathic axonal polyneuropathy reduces disability, ameliorates neurological symptoms and associated impairments, and whether treatment is safe.

SEARCH STRATEGY

We searched Cochrane Library (Cochrane Neuromuscular Disease Review Group Register, Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effectiveness, and the Cochrane Central Register of Controlled Trials), MEDLINE, EMBASE, ISI, and ACP Journal Club's Best Evidence, from 1981 until December 2002. We also hand searched the reference lists of relevant articles, reviews and textbooks identified electronically, and contacted authors and other experts in the field to identify additional studies.

SELECTION CRITERIA

We sought all randomised or quasi-randomised (alternate or other systematic treatment allocation), unconfounded trials that examined the effects of any drug therapy in patients with chronic idiopathic axonal polyneuropathy at least one year after the onset of treatment. Patients with chronic idiopathic axonal polyneuropathy had to fulfil the following criteria: age 40 years or older, distal sensory or sensorimotor polyneuropathy, absence of systemic or other neurological disease, chronic clinical course not reaching a nadir in less than two months, exclusion of any recognised cause of the polyneuropathy by medical history taking, clinical or laboratory investigations, electrophysiological studies in agreement with axonal polyneuropathy without evidence of demyelinating features. The primary outcome was the proportion of patients with a significant improvement in disability. Secondary outcomes were change in the mean disability score, change in the proportion of patients who make use of walking aids, change in the mean Medical Research Council sum score, degree of pain relief and/or reduction of other positive sensory symptoms, change in the proportion of patients with pain or other positive sensory symptoms, and frequency of adverse effects.

DATA COLLECTION AND ANALYSIS

Two reviewers independently reviewed and extracted details of trial methodology and outcome data of all potentially relevant trials.

MAIN RESULTS

Eighteen studies were identified and assessed for possible inclusion in the review, but all were excluded because of insufficient quality or lack of relevance.

REVIEWERS' CONCLUSIONS

Even though chronic idiopathic axonal polyneuropathy has been clearly described and delineated, no adequate randomised or quasi-randomised controlled clinical treatment trials have been performed. In their absence there is no proven efficacious drug therapy.

Comparison of functional results of nerve graft, vein graft, and vein filled with muscle graft in end-to-side neurorrhaphy

End-to-side neurorrhaphy is an alternative method in the situation where the proximal part of the nerve cannot be found. When the intact nerve is not close enough to perform end-to-side neurorrhaphy, it will be necessary to use a graft for transporting the regenerating axons. In this study, we tried to find out whether it is possible to use a graft in an end-to-side neurorrhaphy, and compared the nerve graft with possible alternative grafts, i.e., vein and muscle-filled vein grafts. Thirty male Sprague Dawley rats were used, with an average weight of 293 g (range, 250-350 g). All experiments were done on the right side. A 2-cm nerve graft, beginning 1 cm distal to the branching level, was sectioned from the peroneal nerve. A 1-mm epineural window was opened in the tibial nerve. In the first group, the proximal side of this graft was sutured to the tibial nerve side in an end-to-side fashion, and the distal side was sutured to the distal peroneal nerve stump in an end-to-end fashion. In the second group, the right 2-cm jugular vein was harvested, and was used to bridge the defect instead of the nerve graft used in the first group. In the third group, a 2-cm jugular vein filled with fresh skeletal muscle was used to bridge the defect. At 2, 4, 8, 12, 20, and 28 weeks, functional assessment of nerve regeneration was performed, using walking-track analysis. The numbers of myelinated fibers and fiber diameters were measured, and an electron microscopic evaluation was carried out. Based on walking-track analysis and fiber diameters, the differences of all three groups were statistically significant (P < 0.05). While the differences of myelinated fibers between the first and second groups were not significant, the differences between the rest (group 1-group 3 and group 2-group 3) were significant (P < 0.05). Our study showed that, in end-to-side neurorrhaphy, the use of a nerve graft is possible, and a vein graft is also a good alternative, but a muscle-filled vein graft is not.

Utility of subcutaneous fat aspiration for diagnosing amyloidosis in patients with isolated peripheral neuropathy

OBJECTIVE

To determine the value of subcutaneous fat aspiration in patients with sensorimotor peripheral neuropathy.

PATIENTS AND METHODS

We retrospectively reviewed the medical records of all patients undergoing subcutaneous fat aspiration for suspected amyloidosis from January 1, 1994, through December 31,1999. We classified patients undergoing subcutaneous fat aspiration due to peripheral neuropathy into 2 groups: (A) those with isolated peripheral neuropathy and (B) those with any family history and laboratory or clinical findings typically associated with systemic amyloidosis.

RESULTS

The study population consisted of 450 patients with peripheral neuropathy in whom fat aspiration was performed for suspected amyloidosis. This constituted 56% of all fat aspirations performed during the study period. Group A had 143 patients, and group B had 307 patients. None of the patients in group A had a positive subcutaneous fat aspirate, whereas 17 patients (6%) in group B had a positive subcutaneous fat aspirate (P=.002, Fisher exact test). The subcutaneous fat aspirate was most commonly positive in patients with a monoclonal protein or other clinical findings associated with amyloidosis.

CONCLUSIONS

The yield of a subcutaneous fat aspirate in patients with isolated peripheral neuropathy and no other associated family history, signs, or symptoms of amyloidosis is low. Subcutaneous fat aspiration should be reserved for evaluating patients with peripheral neuropathy who also have findings associated with systemic amyloidosis.

Minimally invasive technique for sural nerve harvesting: technical description and follow-up

OBJECTIVES

To provide instruction and the results of a minimally invasive technique for sural nerve harvesting in preparation for interposition nerve grafting during radical retropubic prostatectomy.

METHODS

Twelve men underwent nerve harvesting performed using a tendon stripper. The short-form McGill Pain Questionnaire was completed preoperatively and at 6 months postoperatively.

RESULTS

No significant morbidity from the leg resulted as a result of the sural nerve harvest. The results of the short-form McGill Pain Questionnaire demonstrated no significant sensory or affective changes in the leg. The average operative time for the entire harvesting procedure, including skin closure, was 15 minutes. The estimated blood loss was less than 5 mL (range 2 to 10). No wound infection or skin erythema was observed. The discharge to home was not delayed compared with the usual length of stay after radical retropubic prostatectomy.

CONCLUSIONS

This minimally invasive sural nerve harvesting technique is easy to perform and has minimal morbidity.

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.

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.

Diagnostic value of sural nerve biopsy in chronic inflammatory demyelinating polyneuropathy

OBJECTIVE

To investigate the additional diagnostic value of sural nerve biopsy of 64 patients in whom chronic inflammatory demyelinating polyneuropathy (CIDP) was considered, as sural nerve biopsy is recommended in the research criteria of an ad hoc subcommittee to diagnose CIDP.

METHODS

Firstly, the additional diagnostic value of sural nerve biopsy was analysed with multivariate logistic regression. Six clinical features (remitting course, symmetric sensorimotor neuropathy in arms and legs, areflexia, raised CSF protein concentration, nerve conduction studies consistent with demyelination, and absence of comorbidity or relevant laboratory abnormalities) were entered into a logistic model. Afterwards, all significant features identified from this model, as well as the results of sural nerve biopsy were forced into a second logistic model. Secondly, the diagnostic performance of a neurologist experienced in diagnosis of peripheral nerve disorders was studied by receiver operating characteristics (ROC) curve analysis.

RESULTS

The results of the first logistic analysis showed that CSF protein concentration >1 g/l (odds ratio (OR)=38.5) and neurophysiological studies consistent with demyelination (OR=51.7) were strong predictors of CIDP. When forcing the significant features and the sural nerve biopsy data into the model, an independent predictive value of sural nerve biopsy could not be found. The neurologist was able to discriminate patients with and without CIDP (area under the curve (AUC)=0.95). His diagnostic performance did not improve significantly by offering him the results of sural nerve biopsy.

CONCLUSION

Any additional diagnostic value of sural nerve biopsy in the diagnosis of CIDP could not be shown.

Skeletal muscle lymphocytic vasculitis in systemic lupus erythematosus: relation to disease activity

Lymphocytic vasculitis (LV) characterises systemic lupus erythematosus (SLE) and this potentially reversible lesion, which may be subclinical, may imply overt systemic disease activity. Needle quadriceps muscle biopsy was performed in 26 unselected patients with SLE and the presence of LV in these muscle specimens was compared with SLE disease activity scored using the British Isles Lupus Assessment Group Index (BILAG). Ten of the 22 patients with active disease showed evidence of LV compared with none of the four patients with inactive disease. In the patient group with LV, significantly higher ESR and urine neopterin values were found with P = 0.002 and P = 0.02, respectively compared with patients without LV. Features of vasculitis (as defined by BILAG) were also significantly more common in these patients (P = 0.005). None of the other parameters, including creatine kinase, were significantly different between the two patient subgroups. Thus, LV in needle quadriceps muscle biopsy specimens is a further valuable marker of disease activity in patients with SLE and might provide histological evidence of a systemic vasculitic process in a group of patients with diverse clinical manifestations.