The outcome of decompression for long-standing symptoms of nerve entrapments in the proximal forearm was investigated in a retrospective study of 205 patients using a self-assessment questionnaire, 45 months after the operation. The questionnaire consisted of visual analogue scale recordings of pre- and postoperative pain during rest and activity, questions about remaining symptoms and appreciation of the result and the Disabilities of Arm, Shoulder and Hand form (DASH). Altogether, 59% of the patients were satisfied, 58% considered themselves improved, and 3% as being entirely relieved of all symptoms. Pain decreased significantly (
Entrapment neuropathies are common conditions in the upper extremity. The most common is the carpal tunnel syndrome (CTS) for which diagnosis and treatment usually are uncontroversial.
There are, however, other nerve affections around the elbow that may be more difficult to diagnose. The most frequently involved nerves are believed to be the median and ulnar nerves [
Most nerve entrapments are hypothesized to be caused by external compression. Anatomic structures incriminated include fibro-osseous or fibromuscular tunnels or a muscle which the nerve courses through. In some cases, repetitive stress from overuse may induce muscular changes causing further narrowing which in turn may lead to nerve compression [
The initial treatment is usually conservative, including avoidance of provocative activities, immobilization in a splint, physical therapy, and patient education. When this fails, operation is often called for [
The most frequently applied surgical method is decompression [
In the absence of an established consensus on measuring the outcome of treatment, the efficacy of operation often has to be evaluated based on reduction of subjective symptoms.
The aim of this study was to assess subjective outcome of decompression surgery in a patient cohort with long-standing symptoms where conservative treatment had been insufficient.
From January 2000 to April 2006, 217 consecutive adult patients with clinical signs of entrapment neuropathy in the proximal forearm were operated upon. All patients had long- standing pain over the alleged compression sites, both at rest and during activity, which had not been sufficiently controlled by physiotherapy and pharmacological treatment. Symptoms reported also included paraesthesia and/or numbness along the nerve distributions and disturbed sleep due to pain or numbness in the affected arm. At clinical examination all patients had tenderness at palpation over the suspected compression sites and occasionally weakness in the muscles innervated by the affected nerve. There were no signs of cervical radiculopathy or pathology in the elbow joint.
Two hundred and five patients (94%), 97 men and 108 women, were available for followup at an average of 45 months (range 9–87) after operation. Average age at operation was 46 years (range 18–77). Preoperatively, the mean symptom duration was 33 months (range 3–300). The dominant arm was involved in 137 of the cases. The diagnoses were distributed as follows: 76 patients with affection of the median nerve (pronator syndrome, PS), 33 patients with affection of the radial nerve (radial tunnel syndrome, RTS), 72 patients with affection of the ulnar nerve (cubital tunnel syndrome, CuTS), 20 patients with unilateral involvement of both the median and ulnar nerves, three patients with unilateral median and radial nerve symptoms, and one patient with unilateral ulnar and radial nerve involvement.
The followup consisted of a self-administered questionnaire and the Disabilities of Arm, Shoulder and Hand form (DASH) [
The questionnaire was designed by an independent investigator (BS) and included questions regarding current symptoms, such as paraesthesia and/or numbness, disturbed sleep, and pain at rest and during activity. The intensity of pain, both preoperative and current, was assessed by using two (rest and activity pain) visual analogue scales (VAS) (100 mm; 0, no pain, through 100, most pain imaginable) [
The results of the two pain ratings, VAS recordings (at rest and during activity), both before operation and at the long-term followup, were added, and the means of the total pain scores (TPSs) were used for further calculations.
A reviewer who was not involved in the operation carried out the study, which was approved by the regional ethical review board.
Senior hand surgeons performed the operations. All operations were performed with the patient under general anaesthesia. After exsanguinations a tourniquet inflated to 60–70 mmHg above systolic blood pressure was used. In connection with operation at the proximal elbow, 78 (38%) simultaneous carpal tunnel releases (CTRs) were performed. Of these, 72 (92%) were in patients operated for pronator syndrome and six (3%) for cubital tunnel syndrome. No complications were recorded during the operations.
A curved or S-shaped incision was made at the volar, medial aspect of the forearm, starting at the elbow flexor crease and running distally 6-7 cm. The median nerve was followed distally under or through the pronator teres muscle, depending on the anatomic variations. The nerve was followed with perineural dissection until the superficial flexor arch, which was sharply divided, confirming that the nerve was free from any kind of direct external pressure. The anterior interosseous nerve branch was identified.
In the majority of cases, the radial nerve was approached from the dorsal aspect using a straight 8 cm incision. The brachioradialis and the extensor carpi radialis longus muscles were separated, the medial fascial edge of the extensor carpi radialis brevis was divided as necessary, and the arcade of Frohse was identified. The superficial branch, the muscular branches, and the deep branch—the posterior interosseous nerve (PIN)—were identified. The PIN was then followed to the proximal aponeurotic edge of the supinator muscle, which was sharply incised 2-3 cm, until the PIN was released from any tendinous or fibrotic structures. Some surgeons preferred a volar approach and used a curved incision on the volar, radial aspect of the forearm, extending from the flexor crease and 8 cm distal. The incision in the supinator muscle was similar regardless of the approach. In no case was the distal part of the supinator muscle incised.
The skin incision extended from the medial epicondyle 5 cm distally and 6 cm proximally. One or two sensory nerves were frequently found under the subcutaneous fat immediately distal to the epicondyle and were protected. The fascia was then incised directly over the ulnar nerve distally to the cubital tunnel and the muscle fibres separated. The distal part of the ligament over the cubital tunnel and both the outer and deep fascia of flexor carpi ulnaris were divided distally a few centimetres. Proximal to the medial epicondyle the ulnar nerve was followed 7-8 cm to ascertain no compression from Struthers’ arcade. A portion of the roof of the cubital tunnel, proximal to the epicondyle, was left intact to avoid subluxation of the nerve. A thorough examination was done to ensure that there was enough space for the nerve in the rest of the cubital tunnel. No transpositions were made.
All wounds were covered in soft dressings, and the patients were instructed to use the operated extremity in normal everyday activities immediately after operation. Heavy work or lifting was not allowed for six weeks. In the postoperative rehabilitation program, all patients were followed according to our structured care plan, meaning that a surgeon saw them at least once after the operation or, if needed, until they were back at work or back to their normal activities. All patients were seen by a physiotherapist and instructed in nerve gliding exercises, scar management, and to monitor possible pain and mobility, as well as by an occupational therapist, if necessary, for oedema reduction and/or treatment of scar hyperaesthesia if present.
Data were analysed using STATISTICA v 9.1 StatSoft, Inc. (
Logistic regression was used to test any relationship between the reported outcome and neurophysiologic reading, as well as simultaneous CTR, and time to followup.
The different nerve decompression groups were similar with respect to demographic data except for gender, where the ulnar nerve group had a male predominance while in all other groups there were more women (
Demographics. Study group. Figures represent mean, SD, and absolute numbers.
Median + ulnar | Median | Radial | Ulnar | |
Gender M/F | 6/14 | 34/42 | 11/22 | 45/27 |
Age (years) | 43 (11.0) | 48 (11.0) | 46 (8.9) | 45 (13.7) |
Dominant arm | 17 | 51 | 23 | 43 |
Duration (months) | 49.7 (56.3) | 43.1 (53.4) | 34.5 (27.5) | 31.9 (29.6) |
Follow-up time (months) | 37 (22.5) | 45 (59.4) | 43 (55.2) | 49 (23.0) |
Nerve conduction studies were performed in 131 (65%) of the patients, in whom the suspected clinical diagnosis was confirmed in 96 (73%). There was a significant difference between the groups in the outcome of the neurophysiologic examination where pathological readings were more common in the ulnar nerve group (
Neurophysiological findings of the examined patients
Median + ulnar | Median | Radial | Ulnar | |
Pathologic | 10 | 38 | 3 | 45 |
Normal | 7 | 22 | 2 | 4 |
The reported subjective outcome after the operation showed that 21 patients (11%) considered themselves completely recovered, 91 patients (47%) improved, 57 patients (30%) unchanged, and 23 (12%) worse. There was no significant difference in perceived improvement between the different nerve groups (Figure
Patient self-reported outcome.
For the entire cohort, the categories “completely recovered,” “improved,” “unchanged,” and “worse” corresponded to a postoperative mean DASH score of eight, 31, 45, and 60, respectively. There was a significant correlation between the patient-reported outcome and postoperative DASH in the whole material and in three of the groups (
Relationship between total pain score (VAS) and DASH, and factors related. All correlation coefficients
Median + ulnar | Median | Radial | Ulnar | |
---|---|---|---|---|
DASH | ||||
VAS (total score after operation) | 0.86 | 0.74 | 0.76 | 0.56 |
Satisfaction | NS | 0.49 | 0.58 | 0.28 |
Subjective outcome | NS | 0.65 | 0.67 | 0.35 |
VAS (total score after operation) | ||||
Satisfaction | NS | 0.60 | 0.65 | 0.45 |
Subjective outcome | 0.58 | 0.58 | 0.80 | 0.59 |
Recordings of patient satisfaction showed that 40 patients (21%) were very satisfied, 73 patients (38%) were satisfied, 54 patients (28%) were dissatisfied, and 25 patients (13%) were very dissatisfied with the result of the operation. There was no significant difference between the nerve groups (
Patient-rated satisfaction.
There was a significant relationship between satisfaction and post-operative TPS in the entire cohort and in three of the groups (
A significant relationship was also found between satisfaction and DASH in the entire cohort as well as in three of the groups (
There was a significant relationship between the postoperative TPS and DASH in all the different nerve groups as well as in the whole cohort (
There was a statistically significant association between duration of symptoms and worse outcome as assessed by post-operative TPS in the whole cohort (
One hundred and thirty-four patients (68%) answered that they would consider undergoing the operation again, 36 patients (18%) were indecisive, and 26 (13%) answered negatively. There was no difference between the nerve groups.
Regarding current symptoms, five (3%) of the subjects considered themselves to be completely relieved of all their preoperative symptoms, 11% of their previous paraesthesia or numbness, and 24% were completely relieved of any sleep disturbance. There was no significant difference between the nerve groups.
The results from the two VAS pain ratings, rest pain and activity pain, and the TPS showed a significant decrease after operation
The results from the pain VAS recordings (mm). Mean values, SD, and
Median + ulnar | Median | Radial | Ulnar | |
Pain at rest | ||||
(0 months) | 48.88 (22.79) | 43.92 (27.93) | 44.32 (23.56) | 41.07 (20.58) |
(45 months) | 31.06 (24.86) | 22.42 (25.08) | 29.61 (22.87) | 24.21 (20.20) |
Activity pain | ||||
(0 months) | 60.94 (18.17) | 54.39 (24.13) | 58.07 (21.99) | 55.51 (18.81) |
(45 months) | 50.00 (25.05) | 30.89 (26.89) | 40.42 (23.78) | 37.73 (24.37) |
N.S. | ||||
Total pain score | ||||
(0 months) | 54.90 (16.88) | 49.16 (24.60) | 51.20 (20.87) | 48.29 (17.85) |
(45 months) | 40.53 (23.76) | 26.66 (25.24) | 35.02 (22.59) | 30.97 (21.46) |
There were no significant differences in TPS between the groups neither before nor after the operation.
The mean postoperative DASH score was 35.29 (24.04) points for the whole patient population, for the median plus ulnar group 49.35 (27.44) points, for the median group 33.63 (24.77) points, for the radial group 26.31 (19.60) points, and for the ulnar group 36.95 (22.14) points.
In our relatively large patient population, with long-standing symptoms of nerve entrapment in the proximal forearm, refractory to conservative treatment, we found that a total of 58% of the patients considered themselves to be completely recovered or improved by nerve decompression, although only five (3%) considered themselves to be completely relieved of all their preoperative symptoms. According to the results from the self-reported pain VAS recordings, there were significant decreases of pain in about 70% of the patients at the followup, which appears to be the main benefit of the operation.
Townshend and collaborators [
Fifty-nine percent of the patients were very satisfied or satisfied with the result of the operation.
Numerous factors may contribute to an unfavourable outcome and according to Ruchelsman and coworkers [
The reason why a substantial proportion of the patients in our study did not experience a satisfactory improvement may relate to the severity and duration of symptoms, as we found a significant relationship between total pain score after the operation and the duration of symptoms before the procedure. The importance of symptom duration as a prognostic factor that may significantly influence the result of surgery was highlighted in a recent study of treatment of proximal forearm neuropathy [
Previous studies using patient satisfaction as the primary outcome measurement are few and based on small study samples. In a study by Bolster and Bakker [
We found only one other study in the literature that used subjective improvement as an outcome measurement after ulnar nerve transposition, by Novak and colleagues [
The results presented in these reports are superior to the findings in our study and could possibly be explained by the dissimilarities in group sizes, variations of surgical methods, follow-up times, and patient selection. Another explanation might be that in the present study the surgeons were not involved in the assessments.
Novak et al. [
Accordingly, it appears that patients with ulnar nerve entrapment deserve special attention when surgical treatment is considered. The difficulties in the treatment of ulnar entrapment have been recognised by others, and some authors advocate transposition of the ulnar nerve as the primary treatment [
Some patients in the radial nerve group were dissatisfied with the outcome, and one reason could be the coexistence of a tendinopathy at the lateral epicondyle, which was not resolved by the decompression. It has previously been recognised that it is not infrequent that patients with RTS may have concomitant lateral epicondylitis [
Sixty-eight percent of the patients in our study would definitely consider operative treatment again. This figure is lower than reported in other studies using the same question. In a study on cubital tunnel decompression Nathan and coworkers [
The ability of electrodiagnostic examination to confirm a compressive neuropathy in the forearm is unclear. This uncertainty was the reason why a substantial proportion of the patients in this study were not subjected to this test. According to Mackinnon and Novak [
We were not able to establish any relationship between preoperative pathologic neurophysiologic findings and patient self-reported outcome in any of the nerve groups. LeRoux and associates [
We realize that, since the DASH score was recorded only at followup, it is not useful in evaluating improvement. DASH, in this case, was introduced to illustrate the patient-reported function in relation to the other applied instruments, the subjective outcome score, the total pain score
The strengths of this study are that the patients were consecutively included, the high participation rate (94%), and that an independent researcher designed and conducted the followup. Furthermore, the surgical procedures were performed by a handful of surgeons working in the same setting and using the same protocol. This large sample of patient-reported post-operative results offers valuable insight concerning patient subjective status four years after nerve decompression in the proximal forearm.
Limitations of the present study comprise the absence of a control group, retrospective recall of preoperative pain, and the use of a nonvalidated subjective self-reported questionnaire. Another limitation is that the patient may have difficulties differentiating between symptoms that are strictly associated with the nerve in question and other disorders present during the follow-up period.
In conclusion, in a group of patients with long-standing entrapment neuropathy of the forearm, refractory to conservative treatment, a significant pain reduction was found in approximately 70%. Nearly 60% were satisfied with the results, and 68% would consider operation again. This can be looked upon as a treatment that provides help to a majority of patients where other options have failed; on the other hand, for a large proportion of patients in this study, the operation may be regarded as unnecessary. This underlines the need for improved diagnostic accuracy, and algorithms for patient selection are obvious, and there is a lack of high-quality studies with prospective design.