Junior surgeon learning curve for performing digital planning of a first-line uncemented total hip prothesis.

PURPOSE: Preoperative digital planning of total hip arthroplasty (THA) anticipates difficulties while increasing implant survival. The objective was to establish the learning curve to produce a reliable and reproducible preoperative planning for THA. We hypothesize that a learning curve exists for planning, and we want to determine the number of procedures required to accomplish it. METHODS: This prospective study included patients for THA from 02/11/2019 to 01/11/2022. Ten junior (Juniors) and senior surgeons (Seniors) had received dedicated training in the use of the software. Modeling was done blindly by Juniors and Senior before surgery on a standardized front pelvis X-ray (mediCAD 2D Classic Hospital software). Statistical analyses to establish the learning curve were done to compare the Juniors and Seniors. RESULTS: 60% of the Juniors achieved competence after 31.5 ± 12.9 [14-54] planning sessions for the acetabular implant, and 80% after 30.3 ± 8.3 [17-40] planning sessions for the femoral implant. Femoral neck size was achieved by all ten Juniors after 23.1 ± 6.8 [17-38] planning. The offset was correctly restored on the plan by 30% of the Juniors after 33.5 ± 11.6 [18-46] planning. CONCLUSION: There is a learning curve for 2D planning of uncemented THA. The different planning items seem to have different learning curves. Compared to Seniors, the completion of 75 planning sessions is not sufficient in totality. The competence of the Juniors for the acetabular implant, the length of the neck and the size of the femoral stem are mostly acquired before 75 sessions. LEVEL OF EVIDENCE: Prospective study-Level II.

Quantitative and individualized assessment of the learning curve in preoperative planning of the acetabular cup size in primary total hip arthroplasty.

INTRODUCTION: The aim of the present study was to investigate the learning curves of 2 trainees with different experience levels to reach proficiency in preoperative planning of the cup size based on learning curve cumulative summation (LC-CUSUM) statistics and a cumulative summation (CUSUM) test. MATERIALS AND METHODS: One-hundred-twenty patients who had undergone primary total hip arthroplasty with a cementless cup were selected. Preoperative planning was performed by an experienced orthopedic surgeon. Trainee 1 (student) and trainee 2 (resident) planned the cup size. The trainees were blinded to the preoperative plan and the definitive cup size. Only after a cup size was chosen, the trainees were unblinded to the preoperative plan of the surgeon. LC-CUSUM was applied to both trainees to determine when proficiency in determining the appropriate cup size was reached. A CUSUM test was applied to ensure retention of proficiency. RESULTS: With reference to the preoperative plan of the surgeon, LC-CUSUM indicated proficiency after 94 planning attempts for trainee 1 and proficiency after 66 attempts for trainee 2, respectively. Trainee 1 and 2 maintained proficiency thereafter. With reference to the definitive cup size, LC-CUSUM did not signal competency within the first 120 planning attempts for trainee 1. Trainee 2 was declared competent after 103 attempts and retained competency thereafter. CONCLUSIONS: LC-CUSUM/CUSUM allow for an individualized, quantitative and continuous assessment of planning quality. Based on LC-CUSUM statistics, the two trainees of this study gain proficiency in planning of the acetabular cup size after 50-100 attempts when an immediate feedback is provided. Previous experience positively influences the performance. The study serves as basis for the medical education of students and residents in joint replacement procedures.

Neuropathy of the elderly.

There is an aging of the peripheral nervous system characterized by a decrease in sensory and motor nerve conduction, amplitudes of motor and above all sensory potentials, an abolition of the ankle jerk reflexes and an alteration of proprioceptive sensitivity in almost two-thirds of individuals over 65 years old. These anomalies tend to increase beyond 80 years. However, these signs of aging do not affect the quality of life of the subjects. The causes of peripheral neuropathies in the elderly differ little from those observed before age 65. Of course, hereditary causes are much less frequent, except cases with a late onset, now easily detectable, such as familial amyloidosis. In our climates and in the most developed countries, diabetes remains the most common cause, the prevalence of neuropathy increasing with age. The so-called idiopathic causes are also frequent and despite extensive investigations, nearly 20% of cases remain without etiological diagnosis, but this type of neuropathy is generally mild and not very progressive. The presence of peripheral neuropathy in the elderly can cause real problems in daily life, including the frequency of falls that can be responsible for deleterious bone damage.

Phenotypic spectrum of Charcot-Marie-Tooth disease due to LITAF/SIMPLE mutations: a study of 18 patients.

BACKGROUND AND PURPOSE: Charcot-Marie-Tooth (CMT) 1C due to mutations in LITAF/SIMPLE is a rare subtype amongst the autosomal dominant demyelinating forms of CMT. Our objective was to report the clinical and electrophysiological characteristics of 18 CMT1C patients and compare them to 20 patients with PMP22 mutations: 10 CMT1A patients and 10 patients with hereditary neuropathy with liability to pressure palsies (HNPP). METHODS: Charcot-Marie-Tooth 1C patients were followed-up in referral centres for neuromuscular diseases or were identified by familial survey. All CMT1A and HNPP patients were recruited at the referral centre for neuromuscular diseases of Pitié-Salpêtrière Hospital. RESULTS: Two phenotypes were identified amongst 18 CMT1C patients: the classical CMT form ('CMT-like', 11 cases) and a predominantly sensory form ('sensory form', seven cases). The mean CMT neuropathy score was 4.45 in CMT1C patients. Motor nerve conduction velocities in the upper limbs were significantly more reduced in CMT1A than in CMT1C patients. On the other hand, the motor nerve conduction velocity of the median nerve was significantly lower in CMT1C compared to the HNPP group. Distal motor latency was significantly more prolonged in CMT1A patients compared to the CMT1C and HNPP groups, the latter two groups having similar distal motor latency values. Molecular analysis revealed five new LITAF/SIMPLE mutations (Ala111Thr, Gly112Ala, Trp116Arg, Pro135Leu, Arg160Cys). CONCLUSIONS: Our study delineates CMT1C as mostly a mild form of neuropathy, and gives clinical and electrophysiological clues differentiating CMT1C from CMT1A and HNPP. Delineating phenotypes in CMT subtypes is important to orient molecular diagnosis and to help to interpret complex molecular findings.

Conventional versus fibrin-glue-augmented arterial microanastomosis: An experimental study.

The purpose of this experimental study was to develop an alternative technique of arterial microanastomosis using only 2 stay-sutures augmented with fibrin glue, and to compare it to the conventional technique in arteries of varying diameters mimicking hand arteries. Eight anastomoses were performed in 7 male rats, including 1 anastomosis each on the 2 femoral, iliac, and carotid arteries, and 2 on the subrenal aorta. The conventional technique was used on one side and on the first aorta anastomosis, while augmented anastomoses were performed on the other side and on the second aorta. Patency was tested 10 min after unclamping; clamping time, blood loss, anastomosis quality score (out of 15 points) and artery diameter were recorded. In arteries of diameter 0.5-2.2 mm, augmented anastomoses were on average 10.7 ± 3.2 min faster to perform (p < 0.0001), with an average of 1.3 ± 0.9 g less blood loss (p < 0.0001) and an average of 2.6 ± 2.5 points higher quality score (p < 0.0001). There were no significant differences between the two techniques in terms of patency rate, regardless of artery size. However, 3 of the 7 augmented anastomoses were non-permeable in the femoral subgroup (i.e., submillimetric arteries). This straightforward technique appears to be time-saving and reliable, provided that the repaired artery is of sufficient size. Subject to clinical validation, this technique might help surgeons treating extensive hand wounds with multiple severed neurovascular bundles.

Non-anti-MAG DADS neuropathy as a variant of CIDP: clinical, electrophysiological, laboratory features and response to treatment in 10 cases.

BACKGROUND AND PURPOSE: Some patients within the spectrum of chronic inflammatory demyelinating polyradiculoneuropathies (CIDP) have distal acquired demyelinating symmetric (DADS) neuropathy, usually associated with anti-myelin-associated-glycoprotein (MAG) IgM monoclonal gammopathy. The aim of this retrospective study was to investigate patients with DADS neuropathy without anti-MAG antibodies, and study their response to immunotherapy. METHODS: Patients were selected on the basis of (i) 'Definite CIDP' according to the EFNS/PNS Guideline criteria, (ii) The presence of disproportionately prolonged motor latencies resulting in a terminal latency index (TLI) ≤ 0.25 in at least two motor nerves and (iii) The absence of anti-MAG antibodies on ELISA. Response to immunotherapy was defined as persistent improvement by at least one point on the INCAT disability score. RESULTS: Data from 146 CIDP patients were analysed, and 10 patients were included. Six had clinically pure sensory neuropathy, and four had sensorimotor neuropathy. Ataxia was present in nine patients, generalized areflexia in seven and postural tremor in two. Five of the 10 patients had abnormal sensory potentials only in the upper limbs. An associated condition was found in nine patients: two chronic lymphocytic leukaemias, four IgG monoclonal gammopathies (one associated with non-Hodgkin's lymphoma) and two IgM monoclonal gammopathies of unknown significance. Patients were mostly improved with intravenous immunoglobulin (IVIg), corticosteroids, plasma exchanges, or a combination thereof. CONCLUSION: DADS neuropathy without anti-MAG antibodies is more likely to be considered a variant of CIDP. In addition, such patients should be systematically investigated for an associated haematological or immunological condition.

European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of chronic inflammatory demyelinating polyradiculoneuropathy: report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society - first revision.

BACKGROUND: Consensus guidelines on the definition, investigation, and treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) have been previously published in European Journal of Neurology and Journal of the Peripheral Nervous System. OBJECTIVES: To revise these guidelines. METHODS: Disease experts, including a representative of patients, considered references retrieved from MEDLINE and Cochrane Systematic Reviews published between August 2004 and July 2009 and prepared statements that were agreed in an iterative fashion. RECOMMENDATIONS: The Task Force agreed on Good Practice Points to define clinical and electrophysiological diagnostic criteria for CIDP with or without concomitant diseases and investigations to be considered. The principal treatment recommendations were: (i) intravenous immunoglobulin (IVIg) (Recommendation Level A) or corticosteroids (Recommendation Level C) should be considered in sensory and motor CIDP; (ii) IVIg should be considered as the initial treatment in pure motor CIDP (Good Practice Point); (iii) if IVIg and corticosteroids are ineffective, plasma exchange (PE) should be considered (Recommendation Level A); (iv) if the response is inadequate or the maintenance doses of the initial treatment are high, combination treatments or adding an immunosuppressant or immunomodulatory drug should be considered (Good Practice Point); (v) symptomatic treatment and multidisciplinary management should be considered (Good Practice Point).

[Cryoglobulinemic peripheral neuropathy in hepatitis C virus infection: clinical and anatomical correlations of 22 cases]. / Corrélations anatomocliniques des neuropathies périphériques cryoglobulinémiques secondaires à l'hépatite C. Série consécutive de 22 cas.

INTRODUCTION: Cryoglobulinemic neuropathies caused by hepatitis C virus are frequent and may have severe clinical outcomes. The aim of this study was to clarify the clinical and anatomical correlations of these neuropathies. METHODS: Between 1992 and 2007, 22 consecutive patients with cryoglobulinemic neuropathies caused by hepatitis C virus were retrospectively included. Patients were evaluated clinically, electrophysiologically and underwent a neuromuscular biopsy. The group of patients with vasculitis on nerve biopsy was compared with the group without vasculitis. RESULTS: All the neuropathies were axonal with 11 polyneuropathies and 11 mononeuropathies multiplex. The seven patients with medium-sized vasculitis on the nerve biopsy presented an acute sensorimotor mononeuropathy multiplex in six cases (85%), with ischemic conduction block in three cases (42%) and wallerian degeneration in four cases (57%). Among the four patients with small-sized vasculitis, two had a mononeuropathy multiplex (50%) without conduction block (0%) and with wallerian degeneration in one case (25%). The 11 patients without vasculitis (nine lymphocytic perivascular infiltrates and two non inflammatory biopsies) had a polyneuropathy in eight cases (72%) without conduction block and wallerian degeneration (0%). The type of neuropathy was different in the group of patients with vasculitis compared with the group without vasculitis. The neuropathies with vasculitis were significantly different with more frequent mononeuropathies multiplex (p<0.05), acute early stage (p<0.01), disability (p<0.05) and wallerian degeneration (p=0.01). CONCLUSION: Among hepatitis C patients with cryoglobulinemia, neuropathies with small-sized vasculitis show a pattern between severe mononeuropathies multiplex with medium-sized vasculitis and moderate polyneuropathies with lymphocytic perivascular infiltrates. In cryoglobulinemic vasculitis with hepatitis C, the severity of the neuropathy depends on the nature of the cellular inflammation and the size of the vessel involvement.

Validity of diagnostic criteria for chronic inflammatory demyelinating polyneuropathy: a multicentre European study.

BACKGROUND: Diagnostic criteria for chronic inflammatory demyelinating polyneuropathy (CIDP) have variable sensitivity and specificity. Newly published criteria by Koski et al combine clinical and electrophysiological components, either of which suffices to establish the diagnosis. European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) criteria require mandatory electrophysiology, as do other sets of criteria. METHODS: The value of the two above-mentioned sets of criteria, on 151 patients with CIDP, and 162 controls with axonal neuropathy, from four European centres was assessed. Results were compared with Van den Bergh and Piéret's criteria and those of the American Academy of Neurology (AAN). The utility of more extensive nerve-conduction studies was ascertained. RESULTS: Koski et al's criteria had a sensitivity of 63% and specificity of 99.3%. With unilateral, right-sided, forearm/foreleg, four-nerve studies, EFNS/PNS criteria offered a sensitivity of 81.3% and specificity of 96.2% for "definite/probable" CIDP. Van den Bergh and Piéret's criteria had a sensitivity of 79.5% and specificity of 96.9%. AAN criteria were poorly sensitive (45.7%) but highly specific (100%). "Possible" electrophysiological CIDP as per EFNS/PNS criteria were poorly specific (69.2%). More extensive studies increased the diagnostic sensitivity of EFNS/PNS criteria (96.7%) but reduced the specificity (79.3%). CONCLUSIONS: In our patient populations, the EFNS/PNS criteria were the most sensitive and allowed identification of a highly significantly greater number of patients than Koski et al's criteria. The latter were comparable in specificity with the "definite/probable" EFNS/PNS electrodiagnostic subcategories. More extensive nerve-conduction studies improved diagnostic yield but resulted in loss of specificity.

[Multifocal motor neuropathy: a retrospective study of sensory nerve conduction velocities in long-term follow-up of 21 patients]. / Neuropathie motrice multifocale: existe-t-il une altération de la conduction sensitive au long cours? Une étude rétrospective chez 21 patients.

INTRODUCTION: Multifocal motor neuropathy is a well described condition characterized by slowly progressive, predominantly distal, asymmetric limb weakness and wasting, predominantly in the arms within an anatomical distribution of individual motor nerves, with minimal or no sensory involvement. METHOD: The aim of this retrospective study was to look for a significant reduction of the amplitude of sensory potentials in a cohort of 21 patients with defined multifocal motor neuropathy according to the Workshop Report criteria [Workshop Report, 2001. 79th ENMC International Workshop. Multifocal motor neuropathy 14-15 April 2000, Hilversum. The Netherlands. Muscle Nerve 11, 309-314], within a follow-up of at least 3 years. RESULT: Thirteen patients (62%) (Group 1) had a reduction of the amplitude of at least one sensory potential, of whom four patients had abnormalities of two or more sensory potentials, while eight patients (Group 2) had no abnormality. No significant differences were found for gender, age at onset, number of involved motor nerves, CSF protein count, presence/absence of anti-GM1 serum antibodies and response to IgIV between the two groups. CONCLUSION: This study underlines the difficulty in defining criteria for multifocal motor neuropathies capable of distinguishing them from other chronic acquired demyelinating polyneuropathies, and mainly from multifocal acquired demyelinating sensory and motor (MADSAM) neuropathy, also called Lewis-Sumner's syndrome.

Intravenous immunoglobulin as short- and long-term therapy of multifocal motor neuropathy: a retrospective study of response to IVIg and of its predictive criteria in 40 patients.

OBJECTIVE: To document short-term and long-term responses to a single type of intravenous immunoglobulin (IVIg) in a large cohort of patients with multifocal motor neuropathy (MMN). METHODS: A retrospective study was conducted in 40 patients with MMN included on ENMC Workshop criteria, and treated with periodic IVIg infusions between 1995 and 2003. The short-term response was defined as improvement of at least 1 point on the MRC score in at least two affected muscles at 6 months. The population comprised 22 treatment-naïve patients (who had never received IVIg before inclusion), and 18 previously treated patients. For the long-term evaluation (>6 months), the patients were classified into three groups according to the dependency or not on periodic IVIg. In addition, changes in conduction block (CB) and predictive criteria for response to IVIg were explored. RESULTS: The MRC score significantly improved (p<0.0001) in 14 (70%; 95% CI 0.46 to 0.88) of the 20 treatment-naïve patients (missing data for 2 patients). None of the predictive criteria studied were found to be significant. At the end of follow-up (mean of 2.2+/-2.0 years), only 8 of the 40 patients (22%) had significant remission, whereas 25 patients (68%) were dependent on periodic IVIg infusions. The number of CBs decreased or remained unchanged in 12 treatment-naïve patients and increased in 2 such patients. CONCLUSIONS: This study confirmed a significantly high short-term response to IVIg of patients with MMN, but showed contrasted results in long-term follow-up. No predictive factors for response to IVIg were found.

Neuropathy in lymphoma: a relationship between the pattern of neuropathy, type of lymphoma and prognosis?

BACKGROUND: Neuropathies associated with lymphoma (NAL) are rare and present a great clinical heterogeneity, making them difficult to diagnose and worsening their prognosis. OBJECTIVES: (1) To report the different patterns of NAL and discuss the mechanisms encountered; (2) to determine the relationship between a given type of lymphoma and a specific type of neuropathy; and (3) to assess the prognosis of NAL. METHODS: Among 150 patients with lymphoma and neuropathy, we selected 26 in whom the neuropathy was not related to drug induced or IgM-antimyelin associated glycoprotein neuropathies. The pattern of neuropathy was defined in terms of its clinical and electrophysiological features. Neurological improvement, haematological remission and occurrence of death were taken into account to determine the prognosis. RESULTS: 13 patients (50%) had a demyelinating polyneuropathy (PNP), seven (27%) had a radiculopathy linked to proximal root tumoral infiltration and six (23%) had an axonal multiple mononeuropathy (MM) related to distal lymphomatous infiltration or to paraneoplastic microvasculitis. Hodgkin's lymphoma was only associated with demyelinating PNP. High grade B cell lymphoma was strongly associated with radiculopathy. Neurological improvement was observed in 69% of patients with demyelinating PNP, 29% with radiculopathy and 50% with MM. Haematological remission was observed in 46% of patients with demyelinating PNP, 29% with radiculopathy and 83% with MM. CONCLUSIONS: Demyelinating PNP, the most frequently observed neuropathy in this study, had the best neurological prognosis. Chemotherapy combined with immune mediated treatment was the most effective treatment in this group. Identifying the type and mechanism of NAL is crucial in order to define the therapeutic strategy and improve the prognosis.

[Entrapment neuropathies involving the ulnar nerve at the wrist (and into the hand) and the peroneal nerve]. / Neuropathies compressives du nerf ulnaire au poignet (et dans la main) et du nerf fibulaire commun. Données récentes.

We report our experience with patients who underwent surgery for entrapment neuropathies involving the ulnar nerve at the wrist and into the hand and the peroneal nerve. For the ulnar nerve, the cause of the lesion was identified in all patients, generally a cyst which had developed in the Guyon canal. The patients usually recovered completely. For the peroneal nerve, there was a wide variety of causes, with mucoid cysts frequently involved. Recovery was often incomplete, because of the very marked initial axonal damage. We emphasized the need for rapid diagnosis and surgical treatment.

European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of multifocal motor neuropathy.

Several diagnostic criteria for multifocal motor neuropathy have been proposed in recent years and a beneficial effect of intravenous immunoglobulin (IVIg) and various other immunomodulatory drugs has been suggested in several trials and uncontrolled studies. The objectives were to prepare consensus guidelines on the definition, investigation and treatment of multifocal motor neuropathy. Disease experts and a patient representative considered references retrieved from MEDLINE and the Cochrane Library in July 2004 and prepared statements which were agreed in an iterative fashion. The Task Force agreed good practice points to define clinical and electrophysiological diagnostic criteria for multifocal motor neuropathy and investigations to be considered. The principal recommendations and good practice points were: (i) IVIg (2 g/kg given over 2-5 days) should be considered as the first line treatment (level A recommendation) when disability is sufficiently severe to warrant treatment. (ii) Corticosteroids are not recommended (good practice point). (iii) If initial treatment with IVIg is effective, repeated IVIg treatment should be considered (level C recommendation). The frequency of IVIg maintenance therapy should be guided by the individual response (good practice point). Typical treatment regimens are 1 g/kg every 2-4 weeks or 2 g/kg every 4-8 weeks (good practice point). (iv) If IVIg is not or not sufficiently effective then immunosuppressive treatment may be considered. Cyclophosphamide, ciclosporin, azathioprine, interferon beta1a, or rituximab are possible agents (good practice point). (v) Toxicity makes cyclophosphamide a less desirable option (good practice point).

European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of paraproteinaemic demyelinating neuropathies: report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society.

BACKGROUND: Paraprotein-associated neuropathies have heterogeneous clinical, neurophysiological, neuropathological and haematological features. Objectives. To prepare evidence-based and consensus guidelines on the clinical management of patients with both a demyelinating neuropathy and a paraprotein (paraproteinaemic demyelinating neuropathy, PDN). METHODS: Search of MEDLINE and the Cochrane library, review of evidence and consensus agreement of an expert panel. RECOMMENDATIONS: In the absence of adequate data, evidence based recommendations were not possible but the panel agreed the following good practice points: (1) Patients with PDN should be investigated for a malignant plasma cell dyscrasia. (2) The paraprotein is more likely to be causing the neuropathy if the paraprotein is immunoglobulin (Ig)M, antibodies are present in serum or on biopsy, or the clinical phenotype is chronic distal sensory neuropathy. (3) Patients with IgM PDN usually have predominantly distal and sensory impairment, with prolonged distal motor latencies, and often anti-myelin associated glycoprotein antibodies. (4) IgM PDN sometimes responds to immune therapies. Their potential benefit should be balanced against their possible side-effects and the usually slow disease progression. (5) IgG and IgA PDN may be indistinguishable from chronic inflammatory demyelinating polyradiculoneuropathy, clinically, electrophysiologically, and in response to treatment. (6) For POEMS syndrome, local irradiation or resection of an isolated plasmacytoma, or melphalan with or without corticosteroids, should be considered, with haemato-oncology advice.

Follow-up study and response to treatment in 23 patients with Lewis-Sumner syndrome.

Lewis-Sumner syndrome (LSS) is a dysimmune peripheral nerve disorder, characterized by a predominantly distal, asymmetric weakness mostly affecting the upper limbs with sensory impairment, and by the presence of multifocal persistent conduction blocks. The nosological position of this neuropathy in relation to multifocal motor neuropathy (MMN) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is still debated. We report the clinical, biological and electrophysiological features, the course and the response to treatment in 23 LSS patients. The initial symptoms started in the distal part of an upper limb in 70% of patients. They were sensorimotor in 65% and purely sensory in 35% of patients. A cranial nerve involvement was observed in 26% of patients and a distal limb amyotrophy in 52%. The CSF protein level was normal in 67% of patients and mildly elevated in the remainder. None had serum anti-GM1 antibodies. There were multiple motor conduction blocks (average of 2.87/patient), predominantly located in the forearm, whereas demyelinating features outside the blocked nerves were rare. Abnormal distal sensory potentials were found in 87% of patients. The electrophysiological pattern suggests a very focal motor fibre demyelination sparing the nerve endings, whereas sensory fibre involvement was widespread. The course was chronic progressive in 71% of patients and relapsing-remitting in the others. During the follow-up study (median duration of 4 years), half of the patients progressed with a multifocal pattern and the distribution of the motor deficit remained similar to the initial presentation. The other patients showed a progression to the other limbs, suggesting a more diffuse process. Fifty-four percent of the patients treated with intravenous immunoglobulin showed an improvement, compared with 33% of the patients treated with oral steroids. Overall, 73% of patients had a positive response to immune-mediated therapy. LSS may be distinguished from MMN by the presence of sensory involvement, the absence of serum anti-GM1 antibodies and, in some cases, a positive response to steroids. In some of the patients in our study, LSS evolved into a more diffuse neuropathy sharing similarities with CIDP. Others had a clinical course characterized by a striking multifocal neuropathy, which suggests underlying mechanisms different from CIDP. Overall, whatever the clinical course, LSS responded to immune-mediated treatment in a manner similar to CIDP.