Long-term surgical outcome of median nerve injuries

Mohammadreza Emamhadi; Hamid Behzadnia; Sasan Andalib

doi:10.4103/fjs.fjs_31_18

ORIGINAL ARTICLE

Year : 2019 | Volume : 52 | Issue : 3 | Page : 71-75

Long-term surgical outcome of median nerve injuries

Mohammadreza Emamhadi¹, Hamid Behzadnia², Sasan Andalib³
¹ Brachial Plexus and Peripheral Nerve Injury Center, Guilan University of Medical Sciences, Rasht, Iran
² Department of Neurosurgery, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran
³ Neuroscience Research Center, Department of Neurosurgery, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences; Road Trauma Research Center, Poursina Hospital, Guilan University of Medical Sciences, Rasht, Iran; Department of Nuclear Medicine, Odense University Hospital; Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark, Iran

Date of Submission	19-Mar-2018
Date of Decision	05-Nov-2018
Date of Acceptance	21-Dec-2018
Date of Web Publication	17-Jun-2019

Correspondence Address:
Dr. Hamid Behzadnia
Department of Neurosurgery, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht
Iran
Dr. Sasan Andalib
Neuroscience Research Center, Department of Neurosurgery, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht
Iran

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/fjs.fjs_31_18

Abstract

Background: Median nerve integrity is a prerequisite of normal hand function. The median nerve is a frequently injured nerve, and recent evidence indicates that nerve surgery may produce acceptable outcomes. The present study provides a framework of long-term surgical outcomes of median nerve injuries and specifies independent predictors of motor and sensory recovery.
Materials and Methods: In the retrospective study, patients with median nerve injuries undergoing the nerve surgery were reviewed. Mechanism of injury, level of injury (arm, elbow/forearm, and wrist), type of injury and lesion, type of surgical repair, and the time interval from injury to surgery were assessed. The long-term follow-up of motor recovery, sensory recovery, and quality of life was done.
Results: A total of 106 cases with median nerve injuries undergoing nerve surgery were included in this study. Most injuries were at wrist level with a higher frequency of sharp and not in continuity lesions. There was a significant association between the three outcomes (motor recovery, sensory recovery, and quality of life) and smoking, addiction, type of injury, type of lesion, and type of nerve repair. There was a significant correlation between quality of life and muscle force recovery and between quality of life and sensory recovery. Muscle force recovery was significantly correlated with sensory recovery.
Conclusions: The findings of the present study suggest that male and young subjects, lesions in continuity, and injuries treated without grafting may show better surgical outcomes.

Keywords: Median nerve, motor recovery, nerve surgery, outcome, quality of life, sensory recovery

How to cite this article:
Emamhadi M, Behzadnia H, Andalib S. Long-term surgical outcome of median nerve injuries. Formos J Surg 2019;52:71-5

How to cite this URL:
Emamhadi M, Behzadnia H, Andalib S. Long-term surgical outcome of median nerve injuries. Formos J Surg [serial online] 2019 [cited 2021 Jan 24];52:71-5. Available from: https://www.e-fjs.org/text.asp?2019/52/3/71/260439

Introduction

A good hand function is essential for normal daily life. It is even more important than walking, bowel and bladder control, and sexual function in patients with tetraplegia.^[1] A majority of peripheral nerve injuries have been demonstrated to occur on upper extremities.^[2],[3] Such injuries may lead to irreversible disabilities and in turn, impair the function of upper extremities and quality of life.^[3] Median nerve, whose integrity is essential for a normal hand function, is frequently injured. Some of the branches of median nerve can be used for nerve transfer.^[4],[5] In the forearm, the flexor pronator muscles are innervated by the median nerve ^[6] except flexor carpi ulnaris. The median nerve is variable in that musculocutaneous nerve may give a communicating branch to it, or it takes one branch from posterior cord of brachial plexus.^[7] Such muscles pronate the forearm, flex the wrist and the hand digits. Median nerve injury symptomatically results in palsy in the supplied muscles, numbness of the thumb, second and third fingers, and radial side of the ring finger.^[8],[9],[10] Thus, disability in pinching and grasping may be its consequences. Surgical exploration and repair of the median nerve may be required in cases with clinical or electrophysiological evidence of median nerve injuries.^[9],[10]

Surgical outcomes are presumed to depend upon several environmental and biological factors such as regeneration of axons, misdirection of axons, neuronal survival, injury and nerve type, injury mechanism and location, time and method of repair, surgical technique, length of the defect, and age.^[11] It is fundamental to assess the likelihood of recovery of the nerve with patients' demographic and intervention elements to provide realistic expectations and suitable recovery.^[12] Surgical outcomes to be assessed include re-innervations, integrated sensory and motor function, pain, and patient-reported outcomes.^{[12],[13],[14]}

To date, there has been no surgical technique warranting recovery of the hand function following median nerve injuries ^[14] and further work seems essential to improve functional outcomes before and after peripheral nerve repair. In the present study, the aim was to assess long-term surgical outcomes of median nerve injuries and specify independent predictors of motor and sensory recovery.

Materials and Methods

In this retrospective study, traumatic median nerve patients during a 10-year period (from 2001 to 2011) of experience of a single surgeon were reviewed. The inclusion criteria were median nerve surgery due to traumatic nerve injuries between the shoulder and wrist crease. Cases with co-injuries in other peripheral nerves of the upper extremity, amputations of hand and fingers, known neuromuscular disorders or psychological disease, carpal tunnel syndrome, and those under the age of 12 years were excluded from the study. Ultimately, 106 cases (71 males and 35 females) with a mean age of 32.95 ± 14.45 were included.

In cases of transected nerves, the end-to-end epineural repair was carried out. If median nerve injury involved a lesion in continuity with negative intraoperative nerve action potentials, resection and repair with or without graft of the injured nerve would be done. In-continuity lesions with positive nerve action potentials during intraoperative testing underwent external neurolysis with or without internal neurolysis. The repair was performed using microscope with 6-0 or 7-0 nonabsorbable stitches.

Demographic [Table 1] and clinical data regarding gender, age, smoking, addiction, the mechanism of injury [Figure 1], level of injury (arm, forearm and elbow, and wrist), type of injury (sharp or crush), type of lesion (in continuity or not in continuity), type of surgical repair (external or internal neurolysis, primary or secondary suture repair, and graft repair), and the time interval between injury and surgery were collected. The follow-up was categorized into three periods of shorter than 2 years, 2–5 years, and longer than 5 years.

Table 1: Demographic features of the subjects with median nerve injuries

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Figure 1: Different mechanism of median nerve injury (a) suicide attempt (b) dog bite

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Motor recovery was assessed using Medical Research Council grading [Table 2]^[15] (the palmar abduction of digit 1 with grading “0” for no contraction to “5” for normal power). Semmes-Weinstein monofilament test ^[16] were applied to assess sensory recovery, that is, perception of cutaneous pressure threshold, reflecting re-innervations of peripheral targets [Table 3].

Table 2: Muscle force of patients according to medical research council grading

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Table 3: Innervation of the cases according to Semmes-Weinstein monofilament test

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Short form-36 (SF-36)^[17] was used to evaluate the patients' health and quality of life. It is composed of 8 different scaled scores ranging 0–100.

The present study was approved by Institutional Ethics Committee. Data management and analysis was done using SPSS software (version 21, SPSS Inc., Chicago, IL, USA). Percentage and frequency were reported for the qualitative data and mean ± standard deviation were reported for the quantitative data. Association and correlation of demographic and clinical data with motor and sensory recoveries and quality of life were assessed. P < 0.05 was considered statistically significant. Written informed consent was obtained from the participants. The present study was approved by a Local Ethics Committee.

Results

Of the 106 cases investigated in the present study, 35 cases were female (33%) and 71 cases were male (67%). The mean±standard deviation age of the subjects was 32.95 ± 14.45 years. The mean±standard deviation time interval from injury to surgery was 10.5 ± 6.5 weeks (1 day–29 weeks). Most of the injuries were found at wrist level (48.1%) with a higher frequency of sharp (56.6%) and not in continuity (56.6%) injuries.

Active movement against gravity was achieved in 35.8% of the cases [Table 2]. Older age (P = 0.056), smoking (P = 0.013), addiction (P = 0.019), sharp injury (P = 0.003), lesion not in continuity (P = 0.0001), and longer time interval between injury and surgery (P = 0.044) significantly hampered muscle force recovery. Type of surgical repair also significantly influenced muscle force recovery (P = 0.0001).

Most of the patients showed a diminished normal superficial sensation (24.5%) and protective sensation lost and intact deep pressure sensation (24.5%) [Table 3]. Smoking (P = 0.011), addiction (P = 0.038), and lesion not in continuity (P = 0.0001) significantly hampered sensory recovery [Table 3]. The type of surgical repair significantly affected sensory recovery (P = 0.001).

The mean score of SF-36 showing quality of life among all cases reached 66.51 ± 17.30 (30.00–100.00). Smoking (P = 0.0001), addiction (P = 0.0001), co-injury at the same upper extremity (P = 0.016), injury not in continuity (P = 0.017), and sharp lesion (P = 0.031) lowered quality of life of the patients. The type of surgical repair (P = 0.045) also significantly affected quality of life of the patients. Using multivariate logistic regression analysis, addiction, and the type of lesion were found to be predictors of quality of life. This indicates that nonaddicted cases achieved a better quality of life (P = 0.005; odds ratio [OR] = 21.4, 95% confidence interval [CI] = 2.6–177.6) and the nerve lesions in continuity provided higher levels of satisfaction for patients (P = 0.024; OR = 2.7, 95% CI = 1.14–6.4).

Using Spearman coefficient, a significant positive correlation was seen between quality of life and muscle force recovery (P < 0.0001, Spearman r = 0.486) and between quality of life and sensory recovery (P = 0.0001, Spearman r = 0.548). Motor recovery was significantly correlated to sensory recovery (P < 0.0001, Spearman r = 0.802).

Discussion

Despite improvements in surgical techniques, recovery after repair of peripheral nerve injuries is often disappointing and unpredictable,^[18] and independent predictors of a good prognosis are contentious.^[19] Thus, we set out the present study to assess surgical outcomes of the median nerve and its association with patients' demographic features. In the present study, a higher frequency of median nerve injuries among men was observed. It was also shown that smoking, addiction, type of lesion, and type of surgical repair were strong predictors for functional outcome of the median nerve surgery. Jaquet et al.^[20] assessed motor recovery, sensory recovery, and type of injury and found a significant association between the appearance of sensory and motor recoveries (P = 0.01, 95% CI = 0.01–0.04). No association was also found between return to work and injury type (P = 0.47). Work type (OR = 3.1; P = 0.002), injury level (OR = 2.6; P = 0.01), hand therapy (OR = 0.24; P = 0.001), and number of complications (P < 0.001) exerted an impact on return to work.

Hundepool et al.^[19] showed that age, gender, and co-injuries are strong predictors of better surgical outcomes. The duration of recovery was shorter among male and young subjects in the present study. Roganovic ^[21] showed that 68.7%, 33.3%, and 10% of distal, intermediate, and proximal median nerve repairs achieved a successful outcome. In addition, level of repair, time interval from injury to surgery, and length of nerve defect were significantly associated with clinical outcome. Yet, only repair level and time interval from injury to surgery were reported to be an independent predictor of successful outcome. In line with findings of Allan ^[22] we found no significant association between muscle force recovery and age or gender. The type of lesion was also a strong predictor of higher scores. We found no significant association between the surgical outcomes and the follow-up duration. al-Ghazal et al.^[23] showed that healing after nerve surgery was adversely affected by smoking. Similarly, we reached the same conclusion that smoking exerts negative impacts on surgical outcomes of the median nerve. The effect of tobacco smoke on nerve healing was reported.^[24] Ruijs et al.^[25] suggested that age, site, injured nerve, and delay affected prognosis following median and ulnar nerve injury repair significantly. The authors performed a meta-analysis and reported that there was an association between motor and sensory recoveries (Spearman r = 0.62, P < 0.001). Site (OR = 0.46; 95% CI = 0.20–1.10), age (OR = 4.3; 95% CI = 1.6–11.2), and delay (OR = 0.94; 95% CI = 0.90–0.98) were shown to predict motor recovery. The chance of motor recovery of the ulnar nerve was 71% lower than that of the median nerve (95% CI = 0.15–0.55; OR = 0.29). Delay (OR = 0.92; 95% CI = 0.87–0.98) and age (OR = 27.0; 95% CI = 9.4–77.6) were seen to predict sensory recovery. We found that the time interval between injury and surgery is an important predictor of motor recovery after median nerve surgery. In fact, longer time interval between injury to surgery brings a smaller chance of a favorable outcome.

Conclusions

The evidence from the present study indicates that male and young subjects, lesions in continuity and injuries treated with simple interventions bring about better surgical outcomes and smoking or addiction are associated with a poor prognosis for median nerve recovery.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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