1-s2.0-s0363502309004493.pdf

SCIENTIFIC ARTICLE

Patient-Rated Outcome of Ulnar Nerve Decompression: A Comparison of Endoscopic and Open In Situ Decompression Adam C. Watts, MBBS, Gregory I. Bain, MD, PhD

Purpose To report patient-rated outcomes after ulnar nerve decompression at the elbow and to compare the outcome after open in situ decompression with that after endoscopic in situ decompression. Methods Patients having ulnar nerve decompression were evaluated using patient-rated outcome measures. Fifty-five patients were recruited; 3 were lost to follow-up, and 18 were excluded because they had anterior transposition. Of the thirty-four patients followed up for 12 months, 19 had endoscopic decompression and 15 had open in situ decompression. Patient demographics, presenting symptoms, range of elbow movement, grip and pinch strength, and sensation were recorded preoperatively and at 12 months by an independent observer. Postoperative patient satisfaction, pain, and ongoing paresthesia were recorded using visual analog scales. Subgroup analysis was performed to compare the outcome of open in situ decompression with that of endoscopic in situ decompression. Results At 12 months after surgery, the proportion of patients satisfied with the outcome was 9 of 15 (60%) for open in situ surgery and 15 of 19 (79%) for endoscopic in situ surgery. The postoperative complication rate was significantly higher after open in situ decompression than that after endoscopic in situ decompression surgery (10%). Preoperative function scores were predictive of patient-rated satisfaction and were related to McGowan grade. Conclusions The patient-reported outcome of surgical treatment of cubital tunnel syndrome is good but is affected by preoperative symptom severity. Outcomes after open and endoscopic in situ decompression, including the proportion of patients reporting satisfaction and functional improvement, are equivalent, but more patients reported complications after open decompression. (J Hand Surg 2009;34A:1492–1498. © 2009 Published by Elsevier Inc. on behalf of the American Society for Surgery of the Hand.) Type of study/level of evidence Therapeutic III. Key words Cubital tunnel syndrome, decompression, endoscopic, outcome, ulnar nerve. is the second most common neuropathy affecting the upper limb, after carpal tunnel syndrome. The annual agestandardized incidence in the United Kingdom for men

C

UBITAL TUNNEL SYNDROME

From Modbury Public Hospital, North Adelaide, SA, Australia; University of Adelaide, Adelaide, SA, Australia; Royal Adelaide Hospital, Adelaide, SA, Australia; and the Department of Orthopaedic Surgery, University of Edinburgh, Edinburgh, United Kingdom. The authors would like to acknowledge the important contribution made to this study by Ron Heptinstall, Enid Buckton, and Rob Maurmo. Received for publication December 21, 2008; accepted in revised form May 19, 2009.

and women is reported to be 235 and 170 per 100,000, respectively.1 The syndrome has been stratified by McGowan into three grades2: grade I, sensory alteration only; grade II, muscle weakness; grade III, muscle No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Gregory I. Bain, MD, PhD, 196 Melbourne Street, North Adelaide, SA 5006, Australia; e-mail: [email protected]. 0363-5023/09/34A08-0017$36.00/0 doi:10.1016/j.jhsa.2009.05.014

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OUTCOME OF ULNAR NERVE DECOMPRESSION

paresis and wasting. Current treatment for patients with notable persistent symptoms of paresthesia or pain in the ulnar nerve distribution or weakness with wasting of the small muscles of the hand due to ulnar nerve entrapment at the elbow is surgical decompression.3 There is controversy in the literature regarding the best surgical treatment. The options include in situ decompression, subcutaneous or submuscular anterior transposition, and medial epicondylectomy. Current evidence suggests that the results of in situ decompression are equivalent to nerve transposition.4,5 More recently, techniques for endoscopic in situ decompression have been described.6 –10 The aims of this study were to evaluate the outcome after surgery for cubital tunnel syndrome using patientreported measures. The secondary aims were to compare the outcomes for open in situ decompression and endoscopic in situ decompression. MATERIALS AND METHODS With local ethics committee approval, data were collected on all consenting patients having ulnar nerve surgery either as an endoscopic or open procedure under the care of a single surgeon between May 1997 and March 2006. The diagnosis of ulnar nerve entrapment at the elbow was made based on a history including paresthesia or numbness in the ulnar nerve distribution, weakness or wasting of the small muscles of the hand, and a positive elbow flexion provocation test. Nerve conduction studies were performed on all patients preoperatively. A slowed motor conduction velocity in the ulnar nerve across the elbow to below 50 m/s supported the clinical diagnosis. Patients were excluded from the study if nerve conduction studies were normal. Endoscopic group The senior author has developed a technique using the Agee device to perform endoscopic in situ ulnar nerve decompression. After a study demonstrating the safety and efficacy of this technique in a cadaveric model,6 patients were offered endoscopic ulnar nerve decompression as an alternative to open surgery. Patients consenting to endoscopic ulnar nerve decompression were included in this group. Patients with previous surgery at the elbow, with an unstable nerve on examination, or who declined endoscopic surgery had an open decompression procedure with transposition if the nerve was unstable and were allocated to the open group. The nerve was determined to be unstable if it was felt to subluxate over the medial epicondyle on passive elbow flexion.

FIGURE 1: Patient flow.

Open in situ group The open group consisted of consenting patients having surgery prior to the development of the endoscopic technique, patients who met the exclusion criteria for endoscopic decompression (unstable ulnar nerve or previous surgery), and patients who declined endoscopic surgery. Open in situ decompression was performed unless the nerve was unstable at the time of surgery, assessed by passively flexing the elbow and observing the position of the nerve relative to the medial epicondyle. For the unstable nerve, an anterior transposition was performed using either subcutaneous or submuscular techniques. Patients having subcutaneous and submuscular transposition were excluded from study. No patients had medial epicondylectomy. Baseline data Fifty-five patients were recruited to the study. Three were lost to follow-up: 2 from the endoscopic group and 1 from the open in situ group (Fig. 1). Eighteen patients had anterior transposition and were excluded from the study. The mean age of the 34 patients followed up for 12 months was 46 years (range, 21–74 years). The rest of the baseline data were presented in Table 1. Preoperatively, at the time of consent to inclusion in the study, data on presenting symptoms were recorded. Function was measured using the American Shoulder and Elbow Society Function Score (Table 2), with a maximum score of 100 for normal function. An independent observer measured range of elbow movement with a goniometer, grip strength using a Jamar dynamometer (Preston, Jackson, MI), pinch strength using a Pinch Gauge (North Coast Medical, San Jose, CA), and sensation using Semmes-Weinstein monofilaments (North Coast Medical).

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TABLE 1.

Demographics of Subjects by Surgical Group Endoscopic n ⫽ 19

Open In Situ Decompression n ⫽ 15

Total N ⫽ 34

p Value

Median age in years (range)

49 (22–70)

36 (21–74)

46 (21–74)

.158

Number of men (percentage of total)

13 (68)

6 (40)

19 (55)

.097

7 (37)

6 (40)

13 (38)

.851 .311

Group

Number with dominant arm involved (%) McGowan grade (%) Grade I

10 (53)

4 (27)

14 (41)

Grade II

5 (26)

6 (40)

11 (32)

Grade III

4 (21)

5 (33)

9 (27)

TABLE 2.

proportion of patients with a positive test between treatment groups (p ⫽ .406).

Patient Self-Evaluation: Function

Circle the number that indicates your ability to do the following activities. 0 ⫽ unable to do; 1 ⫽ very difficult to do; 2 ⫽ somewhat difficult; 3 ⫽ not difficult. ACTIVITY

SCORE

1. Do Up Top Button on Shirt

0

1

2

3

2. Manage Toileting

0

1

2

3

3. Comb Hair

0

1

2

3

4. Tie Shoes

0

1

2

3

5. Eat with Utensils

0

1

2

3

6. Carry a Heavy Object

0

1

2

3

7. Rise from Chair Pushing with Arms

0

1

2

3

8. Do Heavy Household Chores

0

1

2

3

9. Turn a Key

0

1

2

3

10. Throw a Ball

0

1

2

3

Note: Scores averaged and multiplied by 33 to give a score out of 100. Reprinted with permission from Elsevier. King GJ, Richards RR, Zuckerman JD, Blasier R, Dillman C, Friedman RJ, et al. A standardized method for assessment of elbow function. J Shoulder Elbow Surg 1999;8:351–354. Copyright 1999.

Nerve conduction studies The preoperative nerve conduction studies supported the diagnosis of ulnar nerve entrapment at the elbow in all cases included in the study. In the endoscopic group, the mean motor conduction velocity (MCV) across the elbow was 39.1 m/s (range, 33.3– 48.0 m/s), and in the open in situ group it was 34 m/s (range, 30.0 – 40.0 m/s). This difference was not statistically significant (p ⫽ .127). No patient had an MCV greater than 50 m/s. Provocative test results Preoperatively, 21 of 34 patients had a positive elbow flexion test. There was no statistical significance in the

Semmes-Weinstein monofilament test Preoperatively, 5 of 34 patients had normal sensation on monofilament testing of the little finger of the affected limb, 21 had diminished light touch, and 8 had diminished protective sensation. There were no statistical differences between the groups in the monofilament test results. Subjective outcome assessment At 12-month follow-up, the patients were asked to complete a questionnaire administered by an independent observer. The primary outcome of this study was patientrated satisfaction, which was recorded using yes/no answers and was scored by the patient using a 100-mm visual analog scale (VAS). Patient-reported persistent pain, weakness, or numbness in the ulnar nerve distribution were recorded using yes/no answers and were rated by the patient using a 100-mm VAS. Functional scores were repeated using the American Shoulder and Elbow Society Questionnaire (Table 2). Changes in work and recreational sport status were also recorded. Objective outcome assessment The patients were reviewed at 12 months after surgery by an independent observer. Repeat measures were performed of range of movement of the elbow, strength of grip and pinch, and sensation using the same methods as at recruitment. Complications Patients were invited to report any ongoing complications of surgery. Patients were specifically asked to record the presence of pain or numbness at the elbow to identify possible cutaneous nerve injury secondary to the surgical procedure. Complications

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TABLE 3.

Subjective Outcomes by Surgical Group Group

Endoscopic n ⫽ 19

Number of patients satisfied (%)

15 (79)

Median VAS score/100, % (interquartile range)

90 (69–100)

of surgery and any subsequent surgical intervention were recorded prospectively. Statistical analysis Statistical analysis was performed using SPSS Package for Windows (version 14; SPSS Inc, Chicago, IL). Data comparisons were made between the endoscopic group and the in situ decompression group. All patient data were analyzed on an intent-to-treat basis, so patients remained in their initial groups even if the surgery was altered. Comparison of categorical data was performed with the chi-square test. Comparisons of continuous variables with normal distribution of data were performed with Student’s t-test with the average expressed as means and standard deviation. Continuous data that were not normally distributed were compared using the Mann-Whitney U test, with averages expressed as medians and interquartile range. Comparison of normally distributed continuous data recorded before and after surgery was performed using paired Student’s t-test or Wilcoxon signed ranks test if not normally distributed. Linear regression analysis was performed to examine for factors predictive of patient-rated satisfaction. Differences were considered statistically significant if the p value was less than .05. RESULTS Results of subjective assessment A greater proportion of patients in the endoscopic group (15 of 19; 79%) reported that they were satisfied with the outcome of the procedure at 12 months than that in the open in situ decompression group (9 of 15; 60%) but the difference was not statistically significant (p ⫽ .229) (Table 3). The degree of self-reported patient satisfaction measured on a VAS was a median of 90 for the endoscopic decompression group and 60 for the open in situ group. The difference between the scores for the endoscopic and open in situ groups was statistically significant (p ⫽ .022). There were no statistically significant differences in outcome using patient self-reported measures of ongoing symptoms in the hand (numbness, p ⫽ .096;

In Situ Decompression n ⫽ 15 9 (60) 60 (50–73)

Total N ⫽ 34

p Value

24 (70)

.229

78 (52–99)

.022

TABLE 4. Median VAS Scores for Ongoing Hand Symptoms Preoperatively and Postoperatively by Surgical Group

Group

In Situ Endoscopic Decompression n ⫽ 19 n ⫽ 15

Total N ⫽ 34

Pain (interquartile range) Preoperative

40 (0–70)

60 (20–73)

Postoperative

0 (0–10)

20 (0–50)*

56 (0–70) 0 (0–43)‡

Preoperative

70 (60–70)

74 (71–95)

70 (60–80)

Postoperative

10 (0–78)

40 (10–70)

29 (0–74)§

Preoperative

50 (50–60)

43 (29–59)

50 (30–60)

Postoperative

0 (0–50)

25 (0–50)†

10 (0–50)

Numbness (interquartile range)

Weakness (interquartile range)

Significant reduction in median score from preoperatively on VAS ( *p ⫽ .018, †p ⫽ .028, ‡p ⫽ .007, §p ⫽ .047).

pain, p ⫽ .982; weakness, p ⫽ .154). Ongoing numbness in the hand was reported by 12 of 15 patients after open in situ decompression and 10 of 19 patients in the endoscopic in situ decompression group. Four of 15 patients in the open in situ decompression group had ongoing pain in the ulnar nerve distribution compared with 5 of 19 patients in the endoscopic in situ group. Ten of 15 patients reported ongoing weakness in the hand after in situ decompression, compared with 8 of 19 patients after endoscopic in situ decompression. Based on self-reported VAS, there was a significant improvement in pain scores (p ⫽ .018) and weakness scores (p ⫽ .028) from preoperative to 12-month postoperative assessments for the open in situ decompression group only (Table 4). Improvements were seen in the endoscopic in situ group but did not reach statistical significance (pain, p ⫽ .141; weakness, p ⫽ .496).

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Given the sample size of 19 patients and the change in the means, the study had 84% power to detect a difference in the pain scores and 9% power for the weakness scores. Function scores improved overall from 79 of 100 (interquartile range, 63–92) up to 93 of 100 (interquartile range, 78 –100), but this did not reach statistical significance (p ⫽ .053). The improvements in the endoscopic (92 of 100 to 97 of 100, p ⫽ .462) and open in situ (69 of 100 to 83 of 100, p ⫽ .065) groups were not statistically significant. Results of objective outcome assessment For the endoscopic group, grip strength improved from 86% of the contralateral unaffected side (interquartile range, 57% to 107%) to 91% (interquartile range, 84% to 100%). In the open in situ group, grip strength improved from 76% (interquartile range, 42% to 90%) to 91% (interquartile range, 47% to 102%). These improvements were not statistically significant (endoscopic, p ⫽ .176; open, p ⫽ .735). Pinch strength did not change significantly for any group: endoscopic 90% (interquartile range, 66% to 113) to 91% (interquartile range, 64% to 100%; p ⫽ .753); open in situ 94% (interquartile range, 50% to 105%) to 93% (interquartile range, 52% to 106%; p ⫽ .249). The monofilament test scores in the little finger of the affected hand improved by 1 level for 8 of 34 patients. One patient’s score changed from diminished light touch to diminished protective sensation, and 1 patient’s score changed from diminished protective sensation to loss of protective sensation. No significant changes in range of elbow movement as a percentage of the contralateral side were observed in any group before and after surgery (endoscopic, p ⫽ .655; open, p ⫽ .500). Employment and recreation status At 12-month follow-up, 15 of 34 patients were still employed in their original employment, 5 of 34 patients had changed their jobs, and 13 of 34 patients were not working. Data were not available for 1 patient. Sixteen of 34 patients were participating in their usual sport or recreation, 9 of 34 patients were participating at a lower level, 1 patient was unable to play his usual sports, 6 of 34 patients were not participating in any sport, and data were not available for 2 patients. There were no significant differences between treatment groups (work, p ⫽ .680; sport, p ⫽ .569). Complications of surgery There was 1 patient in the endoscopic group who was converted to open in situ decompression because peri-

TABLE 5. Complications by Surgical Group

Group

Endoscopic n ⫽ 19

In Situ Decompression n ⫽ 15

Total N ⫽ 34

New elbow pain

1

1

2

Scar tenderness

0

2

2

Numbness at elbow

0

3

3

Hematoma requiring decompression

1

0

1

Infection

0

0

0

Total (%)

2 (11)*

6 (40)

8 (24)

*Significantly lower overall postoperative complication rate when compared with open in situ decompression (p ⫽ .044).

neural adhesions prevented safe endoscopic decompression. This patient had a good outcome with 100% satisfaction and no complications and remained in the endoscopic group for data analysis. Postoperative complications included pain or scar tenderness at the elbow that had not been reported preoperatively (4 patients), numbness around the elbow (3 patients), and need for further surgery (1 patient; this patient in the endoscopic group had open in situ decompression performed 4 weeks postoperatively because of an exacerbation of symptoms thought to be due to hematoma). There were significantly fewer postoperative complications in the endoscopic group compared with the in situ decompression group (Table 5, p ⫽ .044). There were no infections and no ulnar nerve injuries. Analysis of potential confounding variables No considerable differences in outcome criteria were identified between genders. The differences in McGowan grade severity between the groups were not statistically significant (p ⫽ .311). Linear regression analysis was performed to examine which factors influenced the primary outcome of patient-reported satisfaction. The single factor that predicted the reported satisfaction was the preoperative function score (R ⫽ .637, p ⫽ .19). There was significant correlation between functional scores preoperatively (p ⫽ .015) and postoperatively (p ⫽ .050) and McGowan grade of cubital tunnel syndrome. Both preoperative and postoperative median function scores decreased with increasing McGowan grade, but the amount of improvement in functional score at 1 year after surgery was similar for all grades (Fig. 2).

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OUTCOME OF ULNAR NERVE DECOMPRESSION

FIGURE 2: Preoperative and 12-month median functional scores by McGowan grade. Error bars indicate 75th percentile.

DISCUSSION The optimal treatment for cubital tunnel syndrome is widely debated. Some authors argue that the primary problem is nerve compression by overlying structures11 and that the syndrome is best treated by decompression of the nerve without removing it from its bed, therefore causing minimal disruption to the vascular supply. Others argue in favor of ulnar nerve transposition or medial epicondylectomy,12–14 citing evidence that the nerve is under tension with elbow flexion15 that can only be relieved by placing the nerve anterior to the medial epicondyle. If transposition is performed, the surgeon must decide whether to leave the nerve in a subcutaneous plane16,17 where it may be prone to repeated trauma or to bury it beneath muscle, which is a more technically demanding procedure. 18 –20 Recent metaanalyses of available evidence suggest that in situ decompression has outcomes comparable with anterior transposition but is associated with a lower risk of complication.4,5 This is supported by a detailed decision analysis model that favors in situ decompression.21 With the acceptance of in situ decompression as an effective treatment for cubital tunnel syndrome, methods for minimally invasive22 and endoscopic-assisted ulnar nerve decompression have been investigated. A technique for endoscopic in situ decompression was first described by Tsai et al.9 Subsequently, alternative techniques have been described,7,8,10,23 with supporting anatomic studies.6 The outcome of endoscopic decompression has been shown to be good in cohort studies7,8,22 and appears equivalent to the reported outcome with open techniques.24,25 The advantage of endoscopic release is a smaller skin incision, approximately 3 cm, and minimal soft

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tissue dissection, which decreases the vascular insult to the nerve and improves the cosmetic appearance of the scar. Open decompression techniques are routinely performed through a longitudinal incision centered on and posterior to the medial epicondyle. Anatomic studies have demonstrated the proximity of the medial antebrachial cutaneous nerve,26 particularly the posterior branch, to the dissection, and these nerves may be inadvertently injured during surgical dissection. Persistent elbow pain, numbness around the elbow, and scar tenderness are recognized complications of the open techniques and may be related to injury to these cutaneous nerves. Three of the 8 patients reporting complications at 12 months in this study were complaining of symptoms directly attributable to cutaneous nerve injury, and a further 4 patients had scar tenderness or persistent elbow pain. All but one of these complications were reported in patients who had an open technique. A potential drawback of the endoscopic technique is the management of the unstable ulnar nerve after decompression. No cases of instability were observed in this study, but preoperative assessment was performed, and patients with an unstable nerve were excluded from endoscopic decompression. The literature reports an 80% to 90% success rate for open cubital tunnel surgery.3 The rates of satisfaction reported here appear relatively low, especially for open decompression; however, it is important to emphasize that the outcomes in this study are patient-rated and not based on the surgeon’s perspective. Previous studies have recorded patient self-reported satisfaction of 83% after medial epicondylectomy,27 and 19 of 20 young, healthy military personnel were satisfied with the outcome after submuscular transposition.28 The number of patients reporting ongoing symptoms of numbness is high, but this is in keeping with reviews of previously published literature.29 This figure of up to 80% may be higher than many surgeons appreciate and certainly needs further attention. The weaknesses of this project include a relatively small study sample, nonrandom allocation of patients to the 2 treatment arms of the study, and differences in preoperative symptom severity between groups. Although the McGowan grades were not significantly different on statistical analysis (p ⫽ .311), these differences may have affected the results because functional scores, which were predictive of patient satisfaction, were related to McGowan grade. Taking account of these drawbacks, the results of this study indicate that the outcome of open in situ decompression and endoscopic in situ ulnar nerve decompression are equivalent 1 year after surgery. The proportion of patients experi-

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encing persistent complications was significantly lower in the endoscopic group (p ⫽ .044), indicating a possible advantage of this method. The patient reports of ongoing symptoms and functional deficit appear to be related to preoperative syndrome severity. This should encourage prompt intervention and preoperative counseling of patients with more advanced stages not to expect full return of function, but rather some persistent symptoms at 12 months. REFERENCES 1. Latinovic R, Gulliford MC, Hughes RA. Incidence of common compressive neuropathies in primary care. J Neurol Neurosurg Psychiatry 2006;77:263–265. 2. McGowan AJ. The results of transposition of the ulnar nerve for traumatic ulnar neuritis. J Bone Joint Surg 1950;32B:293–301. 3. Elhassan B, Steinmann SP. Entrapment neuropathy of the ulnar nerve. J Am Acad Orthop Surg 2007;15:672– 681. 4. Zlowodzki M, Chan S, Bhandari M, Kalliainen L, Schubert W. Anterior transposition compared with simple decompression for treatment of cubital tunnel syndrome. A meta-analysis of randomized, controlled trials. J Bone Joint Surg 2007;89A:2591–2598. 5. Macadam SA, Gandhi R, Bezuhly M, Lefaivre KA. Simple decompression versus anterior subcutaneous and submuscular transposition of the ulnar nerve for cubital tunnel syndrome: a meta-analysis. J Hand Surg 2008;33A:1314.e1–1314.e12. 6. Bain GI, Bajhau A. Endoscopic release of the ulnar nerve at the elbow using the Agee device: a cadaveric study. Arthroscopy 2005; 21:691– 695. 7. Ahcan U, Zorman P. Endoscopic decompression of the ulnar nerve at the elbow. J Hand Surg 2007;32A:1171–1176. 8. Hoffmann R, Siemionow M. The endoscopic management of cubital tunnel syndrome. J Hand Surg 2006;31B:23–29. 9. Tsai TM, Bonczar M, Tsuruta T, Syed SA. A new operative technique: cubital tunnel decompression with endoscopic assistance. Hand Clin 1995;11:71– 80. 10. Nakao Y, Takayama S, Toyama Y. Cubital tunnel release with lift-type endoscopic surgery. Hand Surg 2001;6:199 –203. 11. Iba K, Wada T, Aoki M, Oda T, Ozasa Y, Yamashita T. The relationship between the pressure adjacent to the ulnar nerve and the disease causing cubital tunnel syndrome. J Shoulder Elbow Surg 2008;17:585–588. 12. Popa M, Dubert T. Treatment of cubital tunnel syndrome by frontal partial medial epicondylectomy. A retrospective series of 55 cases. J Hand Surg 2004;29B:563–567. 13. Osterman AL, Spiess AM. Medial epicondylectomy. Hand Clin 2007;23:329 –337, vi.

14. Craven PR Jr, Green DP. Cubital tunnel syndrome. Treatment by medial epicondylectomy. J Bone Joint Surg 1980;62A:986 –989. 15. Gelberman RH, Yamaguchi K, Hollstien SB, Winn SS, Heidenreich FP Jr, Bindra RR, et al. Changes in interstitial pressure and crosssectional area of the cubital tunnel and of the ulnar nerve with flexion of the elbow. An experimental study in human cadavera. J Bone Joint Surg 1998;80A:492–501. 16. Lascar T, Laulan J. Cubital tunnel syndrome: a retrospective review of 53 anterior subcutaneous transpositions. J Hand Surg 2000;25B: 453– 456. 17. Messina A, Messina JC. Transposition of the ulnar nerve and its vascular bundle for the entrapment syndrome at the elbow. J Hand Surg 1995;20B:638 – 648. 18. Leone J, Bhandari M, Thoma A. Anterior intramuscular transposition with ulnar nerve decompression at the elbow. Clin Orthop Relat Res 2001;387:132–139. 19. Pasque CB, Rayan GM. Anterior submuscular transposition of the ulnar nerve for cubital tunnel syndrome. J Hand Surg 1995;20B: 447– 453. 20. Glowacki KA, Weiss AP. Anterior intramuscular transposition of the ulnar nerve for cubital tunnel syndrome. J Shoulder Elbow Surg 1997;6:89 –96. 21. Brauer CA, Graham B. The surgical treatment of cubital tunnel syndrome: a decision analysis. J Hand Surg 2007;32E:654 – 662. 22. Taniguchi Y, Takami M, Takami T, Yoshida M. Simple decompression with small skin incision for cubital tunnel syndrome. J Hand Surg 2002;27B:559 –562. 23. Krishnan KG, Pinzer T, Schackert G. A novel endoscopic technique in treating single nerve entrapment syndromes with special attention to ulnar nerve transposition and tarsal tunnel release: clinical application. Neurosurgery 2006;59(1 Suppl 1):ONS89 –100; discussion ONS89 –100. 24. Nathan PA, Keniston RC, Meadows KD. Outcome study of ulnar nerve compression at the elbow treated with simple decompression and an early programme of physical therapy. J Hand Surg 1995;20B: 628 – 637. 25. Dellon AL, Coert JH. Results of the musculofascial lengthening technique for submuscular transposition of the ulnar nerve at the elbow. J Bone Joint Surg 2004;86A(Suppl 1 Pt 2):169 –179. 26. Lowe JB III, Maggi SP, Mackinnon SE. The position of crossing branches of the medial antebrachial cutaneous nerve during cubital tunnel surgery in humans. Plast Reconstr Surg 2004;114:692– 696. 27. Muermans S, De Smet L. Partial medial epicondylectomy for cubital tunnel syndrome: outcome and complications. J Shoulder Elbow Surg 2002;11:248 –252. 28. Fitzgerald BT, Dao KD, Shin AY. Functional outcomes in young, active duty, military personnel after submuscular ulnar nerve transposition. J Hand Surg 2004;29A:619 – 624. 29. Dellon AL. Review of treatment results for ulnar nerve entrapment at the elbow. J Hand Surg 1989;14A:688 –700.

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