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Year : 2015  |  Volume : 28  |  Issue : 1  |  Page : 80-86

Comparative study between primary versus delayed peripheral nerve repair after various types of injury

1 Department of General Surgery, Faculty of Medicine, Menoufia University, Menoufia, Egypt
2 Department of Neurosurgery, Ministry of Health, Egypt

Date of Submission25-Sep-2013
Date of Acceptance24-Nov-2013
Date of Web Publication28-Apr-2015

Correspondence Address:
Abdel Azim Labib Elhoseny
El Mhalla, El Kobra, Gharbiya
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1110-2098.155949

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The present work was designed to compare primary and delayed peripheral nerve repair after various types of injury.
Peripheral nerve injures are common and involve the upper and lower extremities. These injuries may cause significant deficits and impaired functional recovery. Median and ulnar nerve injuries are examples of such lesions, occurring as isolated or combined injury of both nerves. In contrast to the central nervous system, peripheral nerves have the ability of regenerating. This ability has been utilized for a long time in the treatment of injuries of peripheral nerves.
Patients and methods
We studied 30 patients aged 6-60 years (average 28 ± 14 years) presenting to the Emergency Department and Neurosurgery Outpatient Clinic of Shebien El Kom Teaching Hospital with peripheral nerve injury from February 2012 and May 2013. The patients were followed up until July 2013.
Sixteen (53.3%) patients underwent primary repair, and 14 (46.7%) were treated with a delayed method. The highest number of nerve injuries was at the wrist level (43.3%); the elbow was injured in 23.3% of patients and the least frequent nerve injuries were in the thigh (6.7%).
Success was seen in 14 of 16 patients who underwent primary repair and in seven of 14 patients who underwent delayed repair. Excellent results were common in younger patients.
Recovery following primary repair was faster than in other methods. For reaching excellent results in repairing peripheral nerves, it is important to follow all rules needed for repairing cut peripheral nerves, as well as accurate evaluation and correct repair of injured surrounding soft tissue such as tendons and their synovium and injured vessels.

Keywords: Delayed nerve repair, peripheral nerves, primary repair

How to cite this article:
Zeineldin AA, Mohammed MA, Elhoseny AA. Comparative study between primary versus delayed peripheral nerve repair after various types of injury. Menoufia Med J 2015;28:80-6

How to cite this URL:
Zeineldin AA, Mohammed MA, Elhoseny AA. Comparative study between primary versus delayed peripheral nerve repair after various types of injury. Menoufia Med J [serial online] 2015 [cited 2023 Oct 3];28:80-6. Available from: http://www.mmj.eg.net/text.asp?2015/28/1/80/155949

  Introduction Top

Injuries to the peripheral nervous system can result in substantial functional loss and decreased quality of life because of permanently impaired sensory and motor functions and secondary problems such as neuropathic pain; these can have major social consequences in terms of healthcare and long periods of sick leave [1].

Peripheral nerve injury (PNI) is estimated to occur in 2-5% of multitrauma victims, and managing patients with PNIs in the trauma setting is particularly challenging. Concomitant central nervous system, orthopedic, and vascular injuries easily confound the evaluation of limb function [2].

The traditional treatment for PNIs is repair using microsurgical techniques, either by primary nerve suture, secondary (delayed) repair, or nerve graft, but research to find more successful methods that could improve recovery is ongoing. Their treatment sometimes leads to functional recovery but is mostly incomplete or unpredictable, despite the regular use of sophisticated repair techniques, and the clinician must clearly understand the peripheral nervous system's responses to injury, which reveal surprising degenerating and spontaneous regenerating abilities [3].

The surgical treatment of PNIs is still a challenging and highly demanding procedure. The results have been improved upon by different advances in microsurgical techniques. Nevertheless, the results are not always satisfying, making secondary procedures necessary. Thus, these secondary procedures such as tendon transfers and arthrodesis of different joints must be taken into account during reconstructive planning [4].

This study reviews the results of current surgical repair techniques for inducing neurological recovery following traumatic PNIs.

  Patients and methods Top

This is a prospective study that included 30 patients with PNI who were treated between February 2012 and May 2013 and were followed up until July 2013. They were divided into two groups: the primary repair group, including 16 patients, and the delayed repair group, including 14 patients.

Inclusion criteria were as follows:

  1. Patients of all ages, sexes, and occupations.
  2. All patients who presented to the emergency department and neurosurgery outpatient clinic with PNI.

All patients were subjected to the following:

(1) Complete history:

  1. Personal history.
  2. Complaints.
  3. Present history.
  4. Past history.

(2) Complete examination:

  1. General examination.
  2. Neurological evaluation, which was divided into:

    1. Sensory examination (superficial sensation and deep sensation).
    2. Motor examination for muscle state, tone, power and deep tendon reflexes.

(3) Other investigations (before treatment):

  1. Routine laboratory investigations.
  2. Blood grouping and cross-matching.
  3. Plain radiography for the affected area to exclude any associated fracture.
  4. Electroconductive study in patients with closed nerve injuries when there was delayed recovery of nerve injury (axonotmesis or neurotmesis).

Preoperative evaluation of injuries

  1. PNIs were classified into open and closed injuries.
  2. In open injuries, primary repair was the first choice and was suitable in cases of acute sharp lacerating injuries (glass, knife, and razor blades).
  3. In nerve injuries where the nerve ends were found to be contused and the extent of neural injury could not be accurately determined, delayed primary repair was the choice.
  4. Both neurapraxic and axonotmetic grades of traumatic injury did not require surgical intervention. Patients with such injuries were followed up for 3-4 months to allow any element of neurapraxia to resolve and to permit axonal regeneration to occur beyond the point of injury. If there is no clinical or electrodiagnostic evidence of nerve regeneration and muscle reinnervation, a surgical exploration was performed.

Surgical techniques

  1. External neurolysis involved freeing nerves circumferentially from the surrounding tissues. External neurolysis was almost always performed to isolate nerves whenever the injured nerve was found to be entrapped within tethering fibrous tissue while retaining its continuity.
  2. Surgical resection of tethering and/or compressive extra neural scar may therefore promote the recovery of nerve function. Epineurial repairs were carried out when the nerve had been completely severed. The two ends of the nerve were sutured after adequate preparation. Fine monofilament or multifilament sutures (i.e. 4-0 to 6-0), placed within the external epineurium, were used to approximate either single or groups of fascicles.
  3. The nerve ends were resected back to healthy fascicles, and every attempt was made to maintain the original orientation of the two nerve ends.

Postoperative management after peripheral nerve surgery

  1. Parenteral antibiotics were continued for 5-7 days postoperatively according to the condition of the wounds, followed by oral antibiotics.
  2. Immobilization of the adjacent joint using a cast was followed for 3 weeks.
  3. Postoperative physiotherapy after removal of the splint was allowed.


  1. By serial clinical examinations, as a general rule, all patients were seen postoperatively at 4 weeks for 3 months, and then at 3-month intervals for 1 year.
  2. Range of movement, as well as recovery of strength and sensation, were tested and documented on each visit. Follow-up electrodiagnostic studies carried out every 3 months were useful in detecting early signs of muscle reinnervation.

Methods of assessment of the results

The results at the end of follow-up were analyzed according to the scaling system followed by the Medical Research Council (MRC) nerve injury center developed in 1954.

(1) MRC method of grading muscle power:

  1. M0: complete paralysis.
  2. Ml: flickers of contraction, return of perceptible contraction in the proximal muscles.
  3. M2: contractions with movement of joint when gravity is eliminated.
  4. M3: contractions against gravity only; return of perceptible contraction in the proximal and distal muscles of such a degree that all important muscles are sufficiently powerful to act against resistance.
  5. M4: contractions against gravity and some resistance; return of function as in M3 with the possibility of all synergetic and independent movements.
  6. M5: contractions against powerful resistance; normal muscles; complete recovery.

(2) MRC method of grading sensory power:

  1. S0: absence of any sensory recovery in the autonomous area.
  2. S1: recovery of deep cutaneous pain sensibility within the autonomous area of the nerve.
  3. S2: return of some superficial pain and tactile sensibility within the autonomous area of the nerve.
  4. S3: recovery of pain and tactile sensibility within the autonomous area of the nerve but with disappearance of over-reaction.
  5. S4: return of sensibility as in S3 with recovery of two point discrimination.

(3) The results were classified into:

(a) Satisfactory:

  1. Motor nerve recovery of M4 or better.
  2. Sensory nerve recovery of S3 or better.

(b) Unsatisfactory:

  1. Motor nerve recovery of M3 or less.
  2. Sensory nerve recovery of S2 or less.

Statistical analysis

The t-test was used to assess the statistical significance of difference between two means. From the t-test values and the degree of freedom, the P value is calculated from special tables, and the significance of the results was determined from the 't' distribution tables.

A P value of more than 0.05 was considered insignificant difference; P value less than 0.05 was considered significant; P value less than 0.01 was considered highly significant; and P value less than 0.001 was considered very highly significant.

  Results Top

In this study we found that 73.3% of patients sustained injuries from a sharp object, whereas 20% sustained trauma in road traffic accidents and 6.7% from gunshots. Twenty-four (80.0%) patients sustained trauma resulting in open injury, and six (20.0%) patients had closed injury.

The ulnar nerve was the most injured nerve (40%). The median nerve was injured in 20% of patients. The least frequent nerve injury was that of the common peroneal nerve (3.3%).

The highest frequency of nerve injuries was at the wrist level (43.3%). The elbow was injured in 23.3% of patients, and the least frequent area of nerve injury was the thigh (6.7%).

[Figure 1] and [Table 1] show the results of comparison between primary and delayed repair with respect to sex.
Figure 1: Relation between primary and delayed repair with respect to sex.

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Table 1: Comparison between primary and delayed repair with respect to sex

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More number of male patients were operated upon with delayed repair than with primary repair, with the difference being statistically significant (P < 0.05).

[Figure 2] and [Table 2] show the results of comparison between primary and delayed repair with regard to level of injury: delayed nerve repair at the level of the elbow showed statistically significant difference (P < 0.05) from primary repair.
Figure 2: Relation between primary and delayed repair with respect to level of injury.

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Table 2: Comparison between primary and delayed repair with respect to level of injury

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[Figure 3] and [Table 3] show the results of the comparison between primary and delayed repair with respect to the injured nerve: delayed repair of the ulnar nerve showed a highly significant statistical difference from primary repair (P < 0.01).
Figure 3: Relation between primary and delayed repair with respect to the injured nerve.

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Table 3: Comparison between primary and delayed repair with respect to the injured nerve

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[Figure 4] and [Table 4] show the comparison between primary and delayed repair regarding grade of recovery: patients operated upon with primary repair show a highly significant difference in satisfactory recovery (P < 0.001) compared with those operated upon with delayed repair.
Figure 4: Relation between primary and delayed repair with respect to grade of recovery.

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Table 4: Comparison between primary and delayed repair with respect to grade of recovery

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[Figure 5] and [Table 5] illustrate the comparison between satisfactory and unsatisfactory recovery regarding level of injury: at the level of the elbow unsatisfactory recovery showed significant statistical difference (P < 0.05) compared with satisfactory recovery.
Figure 5: Relation between satisfactory and unsatisfactory recovery with respect to level of injury.

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Table 5: Comparison between satisfactory and unsatisfactory recovery with respect to level of injury

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  Discussion Top

The present work aimed to study the comparison between primary and delayed nerve repair after various types of nerve injuries in both the upper and lower limbs and the factors that affect the results.

Many authors have discussed nerve injuries, methods of repair and factors affecting the results, and most of them have agreed on the same findings.

The functional result of nerve repair in children is better than that in adults. Hidalgo and Shaw [5] support the findings of the study.

Their study was conducted on 20 patients of an average age of 8.9 years. The follow-up time ranged between 29 and 173 months. The results were slightly worse in patients older than 10 years at the time of the reconstructive procedure compared with younger patients. This fact has been attributed to better adaptability of the brain in children to a new afferent impulse pattern presented by misdirected axons as well as to the generally shorter distance that the axons have to grow. In our study, younger patients showed better sensory and motor recovery, although the difference was statistically insignificant.

The mechanism of injury has an important effect on the results of the repair.

The best results in this study were achieved in patients injured by sharp objects compared with other types of injuries. This is probably due to the extent of neural injury. This is in agreement with the results of Omer [6], who evaluated 917 cases with upper limb nerve injuries with particular emphasis on the mechanism of injury. He obtained 44% good recovery in sharp injuries, 31% good recovery in low velocity missile wounds and 21% good recovery in high velocity missile wounds.

Lundborg [7] demonstrated better sensory and motor recovery in sharp lacerations than in crushing or avulsion injuries.

Kline and Hudson [8] reported that nerve repair in high-energy war wounds is significantly inferior to nerve repair in civilian wounds, because the extent of soft tissue damage may affect the results because of physical and chemical factors at the repair site or indirectly by damage to the end organs to be innervated, and may also compromise the blood supply to the nerve.

Extensive soft tissue damage may result in a scarred environment, which increases mechanical stresses at the suture line, decreases diffusion of nutrients and interferes with axoplasmic flow.

In our study, the results were consistent with the above results: sharp laceration injuries showed better results than crush injuries; however, the small number of patients was statistically insignificant.

Primary repair shows itself to be the best strategy for injuries suitable for it. Our results found a statistically significant difference between primary repair and secondary repair.

This matches with the results of Birch and Raji [9], which favor primary repair whenever possible. They reviewed the results of repair of 108 median and ulnar nerves after clean transection injury between the elbow and wrist in 95 patients ranging in age from 15 to 55 years. Of these, 48 nerves had primary suture, 25 had delayed suture, and 35 were grafted. Assessment was based on the methods and grading described by Seddon [10]. Thirteen of 60 secondary repairs or grafts failed, but no primary repair failed completely. There were few excellent results, and they were found only after primary distal repair in younger patients. However, as mentioned above, most bluntly divided nerves should be repaired secondarily. Several weeks after injury, the amount of trimming necessary to reach healthy tissue is obvious. Healthy neural tissue can be reached proximally, whereas degenerated fascicles with minimal interfascicular epineurium can be attained distally.

However, the value of secondary repair in selected cases cannot be ignored, as in cases of blunt injuries, which should be repaired with secondary repair.

The level of injury was a very important factor.

Omer [6] reported good and fair recovery in 59% of distal injuries compared with 30% in proximal injuries in his study on median nerve injuries, as well as good and fair recovery in 44% of distal lesions of ulnar nerve in comparison with 24% good and fair results in proximal ulnar nerve injuries.

Jabaley [11] and Sunderland [12] reported that fascicles in the proximal nerves contain a greater mixture of motor and sensory fibers arranged in plexi that make fascicular alignment more difficult.

In addition, Omer [6] and Tupper [13] reported that the chance of fascicular misalignment at proximal levels is more than at distal levels.

In correlation with the above findings, we were able to show statistical difference in the results of proximal and distal repairs in our study.

Closed injuries were associated with poor outcome when compared with open injuries.

This is probably due to factors related to the extent of neuronal injury and the consequent effect on the surgical repair. The proper exposure of the actual extent of the injury, choice of either primary or secondary repair, and the proper choice of the surgical technique are all easier in cases of open rather than closed injuries. For example, some fractures may be associated with a localized bruise or contusion in the nearby nerve, whereas others are characterized by a significant degree of stretch. Also, Puckett et al. [14] showed that the nerve explodes away from a missile as it approaches but implodes back as the missile passes by. This may result not only in an area of severe focal contusion but also in internal disruption of both axons and their connective tissue framework. Furthermore, this intraneural disruption affects important intraneural vasculature over a varying length of the nerve. This mechanism is surprisingly frequent in gunshot wounds, as many fragments responsible for paralysis do not strike the nerve itself.

However, in our study the small number of patients was statistically insignificant.

  1. In our study, we performed epineurial repair in all cases.
  2. None of our cases required a nerve graft. However, most authors agreed that primary nerve repair without tension is superior to nerve grafts.

  Conclusion Top

To sum, it can be concluded that:

  1. Recovery after primary repair is faster than other methods. For excellent results in the repair of peripheral nerves, it is important to consider all rules in repairing cut peripheral nerves, as well as accurate evaluation and correct repair of injured surrounding soft tissue such as tendons and their synovium and injured vessels. Also, excellent postoperative care and timely physiotherapy and good patient cooperation may affect treatment results.
  2. The timing of nerve repair depends highly on available facilities as well as the experience of the surgeon, but in general, if there is an open injury with a clean sharp nerve transection, immediate repair can be done. But if there is an open injury with a blunt nerve transection then delayed nerve exploration is indicated after repair and/or healing of other wounded tissues. In contrast, if there is a closed injury follow-up by clinical assessment and electrophysiological studies are indicated at 3 months and if there is failure of recovery then surgical exploration is indicated.
  3. Meticulous microsurgical repair of peripheral nerves improves the ultimate functional recovery.

  Acknowledgements Top

Conflicts of interest

There are no conflicts of interest.

  References Top

Jaquet JB, Luijsterburg AJ, Kalmijn S, Kuypers PD, Hofman A, Hovius SE. Median, ulnar, and combined median-ulnar nerve injuries: functional outcome and return to productivity. J Trauma 2001; 51 :687-692.  Back to cited text no. 1
Midha R, Guba A, Geniilif, Kline DG, Hudson AR. Peripheral nerve injection injury. In: Omer GE Spinner M, Venbeek AL, editors. Management of peripheral nerve problems. Philadelphia, PA: W.B. Saunders 2008; 406-413.  Back to cited text no. 2
Rosberg HE, Carlsson KS, Dahlin LB. Prospective study of patients with injuries to the hand and forearm: costs, function, and general health. Scand J Plast Reconstr Surg Hand Surg 2005; 39 :360-369.  Back to cited text no. 3
Hudson TW, Evans GR, Schmidt CE. Engineering strategies for peripheral nerve repair. Orthop Clin North Am 2000; 31 :485-498.  Back to cited text no. 4
Hidalgo DA, Shaw WW. General consideration in the management of nerve injuries [chapter 10]. In: Shaw, WW, Hidalgo, DA, editors. Microsurgery in trauma. Moun Kisco/New York: Futura Publishing Company 1987; 119.  Back to cited text no. 5
Omer GE. Muscle-tendon transfers for traumatic nerve injuries. In: Slutsky D, Hentz VR, editors. Peripheral nerve surgery: practical applications in the upper extremity. Philadelphia: Churchill Livingstone, Elsevier 1974; 205-217.  Back to cited text no. 6
Lundborg G. Nerve repair: clinical aspects [chapter 6]. Nerve injury and repair. Edinburgh, London, Melbourne, and New York: Churchill Livingstone 1988; 196-214.  Back to cited text no. 7
Kline DG, Hudson AR. Selected recent advances in peripheral nerve injury research. Surg Neurol 1985; 24 :371-376.  Back to cited text no. 8
Birch R, Raji AR. Repair of median and ulnar nerves. Primary suture is best. J Bone Joint Surg Br 1991; 73 :154-157.  Back to cited text no. 9
Seddon H. Surgical disorders of the peripheral nerves. Baltimore: Williams & Wilkins 2004; 65 :991-1101.  Back to cited text no. 10
Jabaley ME. Electrical nerve stimulation in the awake patient. Bull Hosp Jt Dis Orthop Inst 1984; 44 :248-259.  Back to cited text no. 11
Sunderland S. Nerve and nerve injuries. 2nd ed. Edinburgh: Churchill Livingstone 1991; 32.  Back to cited text no. 12
Tupper JW. Fascicular repair. In: Gelberman RH, editor. Operative nerve repair and reconstruction. Philadelphia, PA: Lippincott 1991; 295-303.  Back to cited text no. 13
Puckett WO, Grundfest H Damage to peripheral nerves by high velocity missiles without a direct hit. J Neurosurg 1946; 3 :294-305.  Back to cited text no. 14


  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]

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