Neurocirugía Neurocirugía 2009 20: 31-38 2009; 20: entrapment neuropathy at the : decisional algorithm and surgical considerations

C. Mandelli and M. Baiguini

Department of . IRCCS San Raffaele. Milano. Italy.

Summary ulnar en el codo según parámetros concretos. Materiales y técnicas. Entre el 2005 y el 2007, 44 Introduction. We propose our surgical experience pacientes han sido sometidos a cirugía según nuestro and the decisional algorithm we use to select the sur- algoritmo basado en unos parámetros clínicos, clasifi- gical procedure for the at the cados a través de la escala de McGrowan, y otros bio- elbow according to defined parameters. lógicos ( morfología del nervio y cantidad de cicatriz en Materials and methods. Between 2005 and 2007, 44 torno al epicóndilo medial). Los pacientes fueron trata- patients were operated according to our algorithm that dos mediante la decompresión simple "modificada" in is based both on clinical parameters, classified through situ, la transposición subcutánea y submuscular. the McGowan scale, and on biological ones (the nervous Resultados. Después de un control durante 13.4 morphology and the amount of scar around the medial meses, el 70% recuperó la función en un grado, el 16% epicondyle). Patients were treated through "modified" en dos grados y no hubo cambios en el 14%. in situ simple decompression, subcutaneous and sub Además, el 84,8% de los pacientes operados muscular transpositions. mediante la técnica de decompresión modificada in situ Results. After an average follow-up of 13.4 months, presentó excelentes resultados. function improved by one grade in 70% of patients, Conclusión. Proponemos un algoritmo para tratar two grades in 16% and there was no change in 14%. uniformemente pacientes con síndrome del túnel Moreover 84,8% of patients operated through the cubital a través de puntos de vista clínicos y biológicos. modified in situ decompression technique reported an La decompresión modificada in situ es un tratamiento excellent outcome. seguro y eficaz en la mayor parte de pacientes redu- Conclusion. We suggest an algorithm for uniformly ciendo el riesgo de reintervención. treat the patients with syndrome through a clinical and biological point of view. The modified in PALABRAS CLAVE: Transposición anterior. Neurolisis situ decompression is a safe and effective treatment for simple. Nervio ulnar. Síndrome del túnel cubital. the majority of these patients reducing the risk of redo . Introduction

KEY WORDS: Anterior transposition. Simple neurolysis. Ulnar nerve entrapment at elbow is considered the Ulnar nerve. Cubital tunnel syndrome. second most common compression neuropathy of the upper limb after carpal tunnel syndrome4. Neuropatía por atrapamiento del nervio ulnar en el With the normal motion of the elbow, the ulnar nerve is codo: procedimiento decisivo y consideraciones qui- subjected to frictional injuries and compression can occur rúrgicas in 5 anatomic points4,6: the arcade of Struthers14, a second site just proximal to the medial epicondyle, the ulnar Resumen groove, the point between the humeral and ulnar heads of the flexor carpi ulnaris muscle and, finally, where the ulnar Introducción. Proponemos nuestra experiencia qui- nerve leaves the flexor carpi ulnaris. According to different rúrgica y el método decisivo que utilizamos para elegir studies, the ulnar nerve is much more vulnerable to com- la técnica quirúrgica en el atrapamiento del nervio pression through the previous third and fourth anatomic regions5. Recibido: 10-04-08. Aceptado: 20-05-08 The diagnosis of cubital tunnel syndrome is made

30 31 Neurocirugía Neurocirugía Mandelli and col 2009; 20:31-38 2009; 20:

Table 1 Decisional surgical algorithm

MG: McGowan Scale A. Nervous morphology: no anomalous curvature, no or mild calliper variation, no or mild colour anomalies. B. Nervous morphology: anomalous curvature, evident calliper variation, colour anomalies. S. Tissues around the medial epicondyle: presence of a large amount of scar. N. Tissues around the medial epicondyle: no or mild presence of scar. Note: sub-muscular transposition is avoided in patients with cicatrization problems or severe vasculopathy (diabetics....) by a combination of patient symptoms, history, physical The patients were clinically divided into three groups examination and electrodiagnostic studies. Clinical and according to the McGowan scale4,10. Group 1 includes those electromyographic findings provide critical pre-operative patients with irritative manifestations in the ulnar nerve information. distribution without muscle weakness. Group 2 refers to Initial treatment of the syndrome is conservative6. If cases with muscle atrophy on , a this is unsuccessful or neurologic deficits are present the decrease of intrinsic muscle function and abnormal 2-point surgical option is considered. The following techniques of discrimination. Group 3 implies severe paralysis of the decompression are reported in literature1,4,8,11-13,15: simple intrinsic muscles, profound sensory changes and possible decompression (neurolysis), subcutaneous/intramuscular/ claw-. sub-muscular transpositions, subtotal medial epicondylec- All the patients underwent an electromyographic exa- tomy. mination to support the previous clinical findings. We have not found in literature a unanimous consensus The radiographic examination of the elbow was perfor- that could help the surgeon in the choice of the appropriate med only in posttraumatic patients. The patients in Group surgical procedure according to defined parameters. The 1 were treated conservatively for three months and, if no aim of our article is to propose our surgical experience and improvement of the symptoms was observed, referred to the algorithm we use to select a surgical option or the other surgery. The surgical procedure proposed to these patients one. was the decompression in situ as recommended in the lite- A new surgical technique of simple in situ decompres- rature11-13 considering that the ulnar nerve is more vulnera- sion at the elbow is also reported. ble to compression at the groove and between the humeral and ulnar heads of the flexor carpi ulnaris. Materials and methods Our surgical technique implies an external neurolysis and the dissection of the subcutaneous fat that is placed Between 2005 and 2007, 44 consecutive patients with under the nerve (Fig. 1). were operated on in our Neurosurgical The details of the modified in situ decompression are Department by C.M. according to a specific decisional reported: algorithm (table 1). The patient is positioned supine with the arm abducted Thirty four patients were males and 10 were females, and externally rotated and the elbow flexed to about 60°. ranging in age from 20 to 81 (mean, 47 years). Local anaesthesia with Lydocaine is injected.

32 33 Neurocirugía Neurocirugía 2009; 20: Ulnar nerve entrapment neuropathy at the elbow: decisional algorithm and surgical considerations 2009; 20: 31-38

Figure 1. Drawings representing the modi- fied in situ decompression technique. The elbow is flexed to about 60°. A: a fatty flap with its blood supply is partially elevated dissecting the subcutaneous tissue. B: the fat is transposed under the nerve. C: the fat is anchored to the periosteum overlying the medial epicondyle using absorbable stitches.

In our practice we do not use plexic anaesthesia and branches are preserved and retracted whenever possible. tourniquet control. The muscular fascia is exposed and incised along the The nerve is palpated just medially to the humeral course of the nerve. epicondyle and a 6-8 cm curvilinear incision is extended The nerve is identified in its groove and distally follo- around the epicondyle tip. wed widening of its entrance to the cubital tunnel and divi- The skin flap is mobilized and the cutaneous nervous ding the Osborne ligament. The external neurolysis is also

Figure 2. Intraoperative morphology of a right ulnar nerve that is trans- posed in a subcutaneous location (black arrow). No scar tissue is present around the medial epicon- dyle (white arrow).

32 33 Neurocirugía Neurocirugía Mandelli and col 2009; 20: 31-38 2009; 20:

Figure 3. Intraoperative view of a right ulnar nerve that will be trans- posed under the muscle. Note the altered nervous morphology and the high amount of scar around the medial epicondyle (black arrow)

Figure 4. Drawings representing the transpositional techniques and the tissutal parameters. The elbow is extended. A: the ulnar nerve with a preserved elasticity (no anomalous curvature, no or mild calliper variation, no or mild colour anomalies) is transposed in a subcutaneous location. There is no or mild scar tissue around the medial epicondyle. B: The ulnar nerve with an altered morphology is placed under the pronator teres muscle. proximally completed in order to reach a final mobilization We take care that the fatty section attached to the sub- of the nerve. cutaneous tissue doesn't produce a cutaneous fold after the An accurate haemostasis is acquired through bipolar previous procedure because of its stretching. cautery avoiding whenever possible damages to the ner- The aim of this technique is to create a soft "bed" under vous vascular bundle11. the nerve. A fatty flap with its blood supply is partially elevated A final checking ensures that there is no tension or kin- dissecting the subcutaneous tissue. The fat is transposed king of the nerve during the flexion and extension of the under the nerve and anchored to the periosteum overlying arm. the medial epicondyle using 4-0 absorbable stitches. The entire course of the ulnar nerve exposed is inspec-

34 35 Neurocirugía Neurocirugía 2009; 20: Ulnar nerve entrapment neuropathy at the elbow: decisional algorithm and surgical considerations 2009; 20: 31-38

ted to exclude any residual compression. muscular transposition. The wound is closed using 3-0 interrupted Vicryl suture Clinical follow-up examination was performed in all for the subcutaneous layer and subcuticular 4-0 absorbable the patients 4 to 21 months postoperatively with a mean of suture for the skin. 13.4 months and reclassified according to the McGowan Patients in Groups 2 and 3 are referred to surgery which scale. implies subcutaneous or sub-muscular nerve transposition. No operative complications occurred. Besides we did The appropriate procedure is selected considering the not experience postoperative problems linked to the sur- following tissutal parameters that are detected during sur- gical wounds or soft tissues after each of the considered gery: the nervous elasticity and the amount of scar in the techniques. surrounding tissues around the medial epicondyle. Postoperatively 63,6% patients presented an excellent The nervous elasticity is classified according to the ner- outcome with both sensory and motor restitution (nearly vous aspect and morphology: normal situation with sporadic ). On the other A: no anomalous curvature, no or mild calliper varia- hand 27,4% of patients was graded as McGowan 1, 5,5% tion, no or mild colour anomalies. as McGowan 2 and 4,5% as McGowan 3. B: anomalous curvature, evident calliper variation, Results based on a more detailed evaluation showed colour anomalies. that the 84,8% patients operated on through the modified The amount of scar in the surrounding tissues around in situ decompression technique experienced the excellent the medial epicondyle is also classified into two catego- outcome and 15,2% remained in McGowan 1. These results ries: were not linked to the possible presence of subluxation of S: tissues with presence of a large amount of scar. the ulnar nerve over the medial epicondyle. N: tissues with no or mild presence of scar. Among the patients that performed the subcutaneous Patients in McGowan Groups 2 and 3 with a nervous transposition, 33,3% had an excellent outcome, 66.7% aspect classified as A (Fig. 2). are referred to subcuta- were in McGowan 1 and 0% in McGowan 2. Among these neous transposition. On the other hand nerves with a B patients, two were previously operated on through our aspect (Fig. 3) are placed under the pronator teres muscle modified in situ decompression technique. (Fig. 4). Finally, after the sub muscular transposition, 7.6% In all the situations (A and B), if it is present a large reached the excellent outcome, 61.5% improved to amount of scar around the medial epicondyle (S), the McGowan 1, 15.3% to McGowan 2 and 15.6% presented a nerve is placed under the muscle. If no or mild scar tissue McGowan 3. is evident (N), the nerve is placed in the subcutaneous or Results are summarized in Tables 2A and 2B. sub-muscular location according to A or B category (Table Preoperative factors like age or concomitant diseases 1 and Fig.1-4). did not influenced significantly the overall outcome or Besides we prefer to perform a sub muscular transposi- the decision making toward one technique or the other. tion in cases of important neuropathic pain independently Anyway we do not usually perform the sub-muscular trans- by the nerve morphology and surrounding tissue aspect. position in patients with potential cicatrisation problems or On the other hand we usually avoid the sub muscular severe vasculopathy. transposition in patients with cicatrisation problems or severe vasculopathy (diabetics...). Discussion

Results Various surgical procedures have been described for the treatment of cubital tunnel syndrome. Many studies focus Forty-four patients with ulnar nerve entrapment at the on the evolution of surgically treated patients but we have elbow were evaluated. Symptoms were present more than observed that there is not a unanimous consensus regarding 3 months. According to McGowan scale, 28 patients were the choice of the appropriate surgical procedure according in Grade 1, 7 in Grade 2 and 9 in Grade 3. to defined parameters. At operation 32 (72.2 %) patients were noted to have an In other words, from the Literature, we know the results ulnar nerve morphology classified as A and 12 (27,8 %) as of the different surgical techniques and what we can expect B. from a surgical but we do not know the objective The amount of scar was in Class S for 11 (25 %) patients indications of each single procedure. and in Class N for 33 (75 %) patients. In spite of these limitations we have proposed a decisio- According to our decisional algorithm, 63.6% of nal algorithm that could help the surgeon in the choice of patients underwent the modified in situ decompression, the appropriate technique. The algorithm is based both on 6.8% the subcutaneous transposition and 29.5% the sub clinical parameters classified through the McGowan scale,

34 35 Neurocirugía Neurocirugía Mandelli and col 2009; 20: 31-38 2009; 20:

Table 2 A Grades of McGowan improvement for each surgical technique

Surgical technique

Grades of improvement in Modified in situ Subcutaneous Sub-muscular Total the MG scale decompression transposition transposition

-2 0% 67% 38% 16% -1 86% 33% 46% 70% 0 14% 0% 15% 14% MG: McGowan

Table 2 B Grades oimprovement i the McGowan scale following the decisional algorithm

and on biological ones that are represented by the nervous after nervous neurolysis. The simple decompression allows morphology, mirroring the degree of its fibrous invasion, patients to avoid elbow instability and assess good decom- and the amount of scar that reflects the condition of the pression of the nerve using a simple and less invasive tech- surrounding tissues. nique12. It is possible that patients with an irritative history may We have modified the standard technique of in situ have less intraneural fibrosis and would thus be more likely decompression in order to create a peduncolated soft bed to respond to surgery. These patients are usually operated for the decompressed nerve excluding its contact with on through a simple decompression at the elbow according the bony structures. In fact it is our opinion that, despite to the points of major ulnar nerve compression at this level. decompression, an ulnar nerve that remains in strict contact In these cases the nerve usually preserves its elasticity and with the groove after surgery, continues to move inside it the surrounding tissues remains favourable to regeneration after flexion of the elbow compromising its intraneural

36 37 Neurocirugía Neurocirugía 2009; 20: Ulnar nerve entrapment neuropathy at the elbow: decisional algorithm and surgical considerations 2009; 20: 31-38

circulation and with the result of fibroblastic invasion and a specific decisional algorithm does not allow us to draw possible persistence or recurrence of the symptomathology9. general conclusions, we think our report make a contri- Besides our technique is valuable also in cases of ner- bution suggesting a decisional scheme that could help the vous subluxation around the medial epicondyle because surgeon to uniformly treat the patients with cubital tunnel the nerve moves over a flat and soft surface. It is important syndrome through a clinical and biological point of view. that the fatty thickness placed under the nerve should not The modifiedin situ decompression technique is a safe and create a lever effect after elbow flexion. This is the reason effective treatment for the majority of patients affected by to carefully inspect the nervous movements and decom- cubital tunnel syndrome reducing the risk of redo surgery. pression during elbow flexion performed while operating the patient. Another technical point linked to this technique References is the surgical incision. We perform a curvilinear incision that implies a subcutaneous dissection to reach the ulnar 1. Adson, A.W.: The surgical treatment of progressive groove. During this dissection it is mandatory the cuta- ulnar paralysis. Minn Med 1918; 1: 455-460. neous branches sparing in order to avoid postoperative 2. Broudy, A.S., Leffert, R.D., Smith, R.J.: Technical pro- neuronal and local pain. blems with ulnar nerve transposition at the elbow: findings and Patients with McGowan 2 and 3 were referred to trans- results of reoperation. J. Hand Surg. 1978; 3: 85-89. position surgery. In these cases we also considered the bio- 3. Dagregorio, G., Saint-Cast, Y.: Simple neurolysis for logical factors in the decision making: nervous morphology failed anterior submuscolar transposition of the ulnar nerve at and scar. Kleinman demonstrated that anterior transposition the elbow. Intern Orthop (SICOT) 2004; 28: 342-346. is a logical approach to complete nerve decompression7. 4. Dinh, P.T., Gupta, R.: Subtotal medial epicondylectomy The presence of fibrosis and adhesions adversely affects as a surgical option for treatment of cubital tunnel syndrome. the outcome3 and this is the reason we usually place under Tech Hand Up Extrem Surg. 2005; 9: 52-59. the muscle the ulnar nerve in cases of large amount of scar 5. Feindel, W., Stratford, J.: The role of the cubital tunnel extending around the medial epicondyle. The transposed in tardy ulnar palsy. Can. J. Surg. 1958; 1: 287-300. ulnar nerve in a stable environment represents a good solu- 6. Kim, D.H., Han, K., Tiel, R.L., Murovic, J.A., Kline, tion to protect the nerve itself also in cases, defined as B, of D.G.: Surgical outcomes of 654 ulnar nerve lesions. J. Neuro- neural fibrous invasion (assonotmetic damages). We there- surg. 2003; 98: 993-1004. fore exclude the internal neurolysis as suggested by Broudy2 7. Kleinman, W.B.: Cubital tunnel syndrome: anterior and perform the external neurolysis releasing all sites of transposition as a logical approach to complete nerve decom- compression distally and proximally placing the nerve in an pression. J. Hand Surg. [Am] 1999; 24: 886-897. appropriate biological area for regeneration. The sub-muscu- 8. Kline, D.G., Hudson, A.R., Kim, D.H.: Ulnar nerve. lar transposition has also the advantages to place the nerve Atlas of peripheral nerve surgery. Saunders Company (ed). over an anatomic plane that is at the same level of the ulnar 2001: pp. 77-83. nerve branches entering into the flexor carpi ulnaris. This 9. LeRoux, P.D., Ensign, T.D., Burchiel, K.J.: Surgical condition avoids in hypo elastic nerves additional nervous decompression without transposition for ulnar neuropathy: kinking linked to the altered trajectory through different ana- factors determining outcome. Neurosurgery 1990; 27: 709- tomic planes as in the subcutaneous transposition. 714 Following our decisional algorithm, after an average 10. McGowan, A.J.: The results of transposition of the follow-up of 26.4 months (range, 4 to 41 months), func- ulnar nerve for traumatic ulnar . J. Bone Jt. Surg. 1950; tion improved by one grade in 70% of patients, two grades 32B: 293-301. in 16% and there was no change in 14%. A more specific 11. Messina, A., Messina, J.C.: Transposition of the ulnar analysis showed that 84,8% patients operated on through nerve and its vascular bundle for the entrapment syndrome at the modified in situ decompression technique reported an the elbow. J. Hand Surg. 1995; 20B: 5: 638-648. excellent outcome. 12. Nathan, P.A., Keniston, R.C., Meadows, K.D.: Out- According to our follow-up, the duration of symptoms come study of ulnar nerve compression at the elbow treated appears to correlate with outcome moreover in patients with simple decompression and an early programme of physi- classified as McGowan 1. In fact it is our feeling that they cal therapy. J. Hand Surg. [British and European ] 1995; 20B: should be operated on as soon as possible after three months 5: 628-637. of clinical observation if persistent symptoms are present. 13. Nathan, P.A., Istvan, J.A., Meadows, K.D.: Interme- diate and long-term outcomes following simple decompres- Conclusion sion of the ulnar nerve at the elbow. Chir de la Main 2005; 24: 29-34. Although our small number of patients treated through 14. Nathan, P., Myers, L.D., Keniston, R.C., Meadows,

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K.D.: Simple decompression of the ulnar nerve: an alternative to of the upper extremity. Clin Orthop 1974; 104: 46-47. anterior transposition. J. Hand Surg.[Br] 1992; 17B: 251-254. 15. Richmond, J.C., Southmayd, W.: Superficial anterior Mandelli, C.; Baiguini, M.: Ulnar nerve entrapment neu- transposition of the ulnar nerve at the elbow for ulnar neuritis. ropathy at the elbow: decisional algorithm and surgical Clin Orthop Related Res 1982; 164: 42-44. considerations. Neurocirugía 2009; 20: 31-38. 16. Spinner, M., Kaplan, E.B.: The relationship of the ulnar nerve to the medial intermuscular septum in the arm and Corresponding author: Carlo Mandelli MD Divisione di Neuro- its clinical significance. Hand 1976; 16: 239-242. chirurgia IRCCS San Raffaele. Via Olgettina 60. 20132 Milano. 17. Spinner, M., Spencer, P.S.: Nerve compression lesions Italy.

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