Long term follow-up results of dorsal root entry zone lesions for intractable pain after brachial plexus avulsion injuries

Acta Neurochir Suppl (2006) 99: 73–75

# Springer-Verlag 2006 Printed in Austria

Long term follow-up results of dorsal root entry zone lesions for intractable pain after brachial plexus avulsion injuries

H. J. Chen and Y. K. Tu

Department of Neurosurgery and Orthopedics, E-Da Hospital and I-Shou University, Kaohsiung Hsien, Taiwan

Summary

Brachial plexus avulsion injury is one of the major complications after traffic, especially motorcycle accidents and machine injuries. Intractable pain and paralysis of the affected limbs are the major neurological deficits. During the past 18 years, we have encountered and treated more than 500 cases with brachial plexus avulsion injuries. Dorsal root entry zone lesions (DREZ) made by thermocoagulation were performed for intractable pain in 60 cases. Forty cases were under regular follow-up for 5–18 years. In early postoperative stage, the pain relief rate was excel- lent or good in 32 cases (80%). The pain relief rate dropped to 60% in 5 year follow-up period and only 9 cases (50%) had excellent or good result in 10 year follow-up. Reconstructive procedures were performed in almost all patients in the last 10 years. Dorsal root entry zone lesion is an effective procedure for pain control after brachial plexus avulsion injuries.

Keywords: Brachial plexus avulsion injury; dorsal root entry zone;

neural reconstruction.

Introduction

Brachial plexus avulsion injury is one of the major complications after traffic, especially motorcycle acci- dents and machine injuries [2–5]. Motorcycles are the main transportation vehicle in many developing coun- tries. Intractable pain after root avulsion and paralysis in the affected limbs are the consequences of brachial plexus injury. Since the majority of patients are young and middle aged people, the disability due to pain and paralysis does usually result in limitation of social activ- ities and employment [3–5, 9].

Pain occurs frequently after injury, starting usually within weeks of the event and then, becomes chronic.

The pain is almost unresponsive to medication, includ- ing narcotics and anticonvulsants [2, 6, 7]. Surgical treat- ment including dorsal root entry zone lesion (DREZ) has been used for control of pain [6–9]. For brachial plexus

avulsion injury, neurosurgeons, plastic surgeons, and orthopedic doctors cooperate in trying to relieve the pain and restore the function of the affected limbs [1, 4, 5]. In the past 18 years, we have encountered more than 500 patients with brachial plexus injury. Dorsal root entry zone lesions were used for pain control.

Material and method

Since 1987, we have treated more than 500 cases with brachial plexus injuries. The main complaints were intractable pain and paralysis of the affected limbs. Injuries were evaluated by physical examination, electro- diagnostic studies and imaging studies including myelography in early years, thereafter magnetic resonance imaging in the last 15 years (Fig. 1) [1, 4, 5, 9].

Sixty patients underwent DREZ lesions with radiofrequency thermo- coagulation for pain control. Among these 60 cases, 40 cases had 5–18 year follow-up [9, 10]. There were 36 male and 4 female patients. Age distribution was from 25 to 71 years with a mean age of 49.5 years. The intervals between injury and surgery varied from 0.5 to 25 years with a mean of 8.5 years. Seventeen cases had injuries on the right. Thirty-two cases suffered from complete brachial plexus avulsion injuries; 5 cases with upper brachial plexus injuries and 3 with lower brachial plexus injuries. All patients were found to have poor response to medical treat- ment and underwent DREZ lesions. DREZ surgery might be performed before or after nerve reconstruction. The surgical principles were per- formed following Nashold method [8] with some modification. Hemila- minectomy regions depended on the avulsed roots. For a complete brachial plexus avulsion injury, hemilaminectomy from C4 to T1 was performed to expose the whole lesion site. The electrode had an internal thermistor to measure the temperature of lesion site and was introduced into the cord along the posterior lateral sulcus into the dorsal horn of the cord. Each lesion was made at a temperature of 75

C for 15 to 20 (in the C5–6 cord) seconds (Fig. 2). The interval between two lesions was about 1–2 mm.

Most patients in the last 10 years underwent different kinds of recon- structive procedures for brachial plexus injuries. The procedures were performed depending on the condition of injuries and might be before or after DREZ surgery for pain control [4, 5].

Almost all patients were under regular follow-up for adjuvant proce-

dures or adjustment of medication. These could help patients for a better

quality of life.

Results

In the initial stage, thirty-two patients (80%) had excel- lent-good pain control after DREZ surgery. Five patients had only fair results and three complained of no improve-

ment. After 3 years’ follow-up, the excellent-good pain control group dropped to 75% (30 cases). There were 38 patients with 5 year follow-up and 23 patients (60%) still had excellent-good results. The patients needed narcotics for pain control and five patients complained of return of original pain despite medication. After a 10 year follow- up, 9 cases (50%) had at least good result and 5 cases needed narcotic pain control (Table 1).

Two patients underwent stereotactic thalamotomy 2 and 3 years after DREZ surgery due to recurrence of pain. One showed good postoperative result.

Discussion

The clinical manifestations after brachial plexus avul- sion injury are mainly intractable pain and paralysis of the affected limb. The goal of treatment is early return to social activities or even work [4, 5, 10]. The deafferen- tation pain after root avulsion is very incapacitating.

There were five patients in our series that committed suicide and half of patients had thought about suicide [4]. In our experience, pain may happen in about one third of patients. Good pain control is treatment priority.

For pain control, our experience suggests that DREZ can be performed as early as possible. There were no major postoperative complications encountered in our 60 cases. Temporary ataxic gait might be found in about 15 cases (25%). This symptom usually improved gradu- ally to near normal gait within 3 months [4]. Although opinions differ regarding the timing of DREZ surgery, most authors recommended surgery within 3 to 6 months of injury. Most patients in our series underwent explora- tion later than this period. This is due to patients’ hesita- tion or inadequate information. Five patients underwent above elbow amputation before DREZ surgery. Unfortu- nately, phantom limb pain developed. We do not recom- mend this surgical procedure in those patients.

Though pain relief rate after DREZ surgery decreased year by year, it is still a treatment choice for intractable pain after brachial plexus avulsion injury. Good pain control definitely gives patients much benefit in social activities and employment.

References

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Fig. 1. A case suffered from right brachial plexus avulsion injury and complete paralysis in the right upper limb. MRI showed traumatic meningoceles in cervical and upper thoracic spine

Fig. 2. All dorsal roots were torn (arrow)

Table 1. Long term follow-up of pain relief rate after DREZ surgery Follow-up

Result

Early stage

3 year follow-up

5 year follow-up

10 year follow-up Excellent–good 32 (80%) 30 (75%) 23 (60%) 9 (50%)

Fair 5 (12.5%) 5 (12.5%) 10 (27%) 5 (28%)

No improvement 3 (7.5%) 5 (12.5%) 5 (13%) 4 (22%) Excellent Nearly no medication for pain, good analgesics were needed sometimes, Fair narcotics were needed, no improvement original pain persisted.

74 H. J. Chen and Y. K. Tu

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Correspondence: Han-Jung Chen, M.D., Ph.D., Department of Neurosurgery, E-Da Hospital, No. 1, E-Da Road, Yanchao Hsiang, Kaohsiung Hsien 824, Taiwan. e-mail: [email protected]

Long term follow-up results of dorsal root 75